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Udgivelsesdato: 2008-Feb BACKGROUND: Cardiac surgery is the standard treatment for unprotected left main disease (ULM). Drug-eluting stent (DES) implantation has been recently reported in patients with ULM but with unclear results. We systematically reviewed outcomes of percutaneous DES implantation in ULM. METHODS: Several databases were searched for clinical studies reporting on > or = 20 patients and > or = 6-month follow-up. The primary end point was major adverse cardiovascular events (MACEs; ie, death, myocardial infarction, or target vessel revascularization [TVR]) at the longest follow-up. Incidence and adjusted risk estimates were pooled with generic inverse variance random-effect methods (95% CIs). RESULTS: From 823 initial citations, 16 studies were included (1278 patients, median follow-up 10 months). Eight were uncontrolled registries, 5 nonrandomized comparisons between DES and bare-metal stents and 3 nonrandomized comparisons between DES and CABG, with no properly randomized trial. Meta-analysis for DES-based PCI showed, at the longest follow-up, rates of 16.5% (11.7%-21.3%) MACE, 5.5% (3.4%-7.7%) death, and 6.5% (3.7%-9.2%) TVR. Comparison of DES versus bare-metal stent disclosed adjusted odds ratios for MACE of 0.34 (0.16-0.71), and DES versus CABG showed adjusted odds ratios for MACE plus stroke of 0.46 (0.24-0.90). Meta-regression showed that disease location predicted MACE (P = .001) and TVR (P = .020), whereas high-risk features predicted death (P = .027). CONCLUSIONS: Clinical studies report apparently favorable early and midterm results in selected patients with ULM. However, given their limitations in validity and the inherent risk for DES thrombosis, results from randomized trials are still needed to definitely establish the role of DES implantation instead of the reference treatment, surgery.

Percutaneous coronary intervention (PCI) has played an integral role in the therapeutic management strategies for patients who present with either acute coronary syndromes or stable angina pectoris. The COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial enrolled patients with chronic stable angina and at least 1 significant (or =70%) angiographic coronary stenosis who were randomly assigned to an initial treatment of either PCI in conjunction with optimal medical therapy or optimal medical therapy alone. Although the initial management strategy of PCI did not reduce the risk of death, myocardial infarction, or other major cardiovascular events, improvement in angina-free status and a reduction in the requirement for subsequent revascularization was observed. An in-depth analysis of the COURAGE trial design and execution is provided.

In the PLATINUM randomized controlled trial, the PROMUS Element Everolimus Eluting Stent (PtCr-EES) was non-inferior to the cobalt chromium PROMUS/XIENCE V EES (CoCr-EES) for the primary endpoint of 12-month target lesion failure (TLF; the composite rate of target vessel-related cardiac death

Objective: The goal of this study was to determine whether three-dimensional (3D) reconstruction of traditional coronary angiography could optimize the choice of drug-eluting stent (DES) length and number during percutaneous coronary intervention (PCI). Background: Coronary angiography is subject to significant foreshortening artifact that limits the ability of the operator to accurately determine lesion length. Methods: The angiographic images of the target vessels of consecutive PCI procedures were postprocessed using a 3D reconstruction algorithm. The appropriate length and optimal number of DES to span each target lesion were calculated and compared with the number and length of DES actually chosen by the operator. Results: A total of 42 target vessels were analyzed, and 3D reconstruction was successful in 38/42 (90.5%) of cases. The results of 3D analysis would have changed operator decision making in six cases (16%): in four cases, the stent chosen by the operator was too short requiring an additional DES; in two cases, the chosen DES was too long and exchanged for a shorter one. In each of these six cases, 3D analysis would have determined the correct stent length prior to stent selection. The optimal stent number derived by 3D reconstruction was significantly less than the actual number of stents per lesion used by the operator (1.31 6 0.47 versus 1.54 6 0.68, P = 0.01), and the optimal stent length trended less than the actual stented length (27.5 6 12.8 mm versus 28.7 6 14.7 mm, P = 0.23). Conclusions: 3D reconstruction algorithm of standard coronary angiography is a promising technique to improve DES utilization during PCI. ' 2006 Wiley-Liss, Inc.

The optimal treatment for sirolimus-eluting stent (SES) restenosis is not known. This study evaluated the safety and clinical outcome of paclitaxel-eluting stent (PES) implantation for SES restenosis. From March 2004 to July 2005, PESs were implanted in 125 patients with 140 lesions with SES restenosis. Acute and 6-month clinical outcomes were determined through review of the medical record and/or telephone interview. In-hospital major adverse cardiac events (death, nonfatal myocardial infarction, or repeat revascularization) occurred in 14 patients (11.2%), driven entirely by postprocedure non-Q-wave myocardial infarction. At a mean clinical follow-up of 7.2 +/- 1.8 months, the incidence of target lesion revascularization (TLR) was 14.0%, and the rate of major adverse cardiac events was 17.2%. Subacute thrombosis occurred in 2 patients (1.6%). Length of PES implanted, postprocedure diameter stenosis, and total occlusion of the target lesion were independent predictors of TLR. In patients with de novo SES restenosis, TLR was only 8.7%. In conclusion, at medium-term follow-up, PES implantation for SES failure appears to be safe and effective, although efficacy is decreased in the setting of total occlusions, greater residual diameter stenosis, and longer PESs.

A randomized, controlled clinical trial demonstrated that intravenous (IV) fenoldopam did not prevent further deterioration in renal function after contrast administration in patients with chronic renal insufficiency. This lack of effect may have been a consequence of the inability to administer an effective renal dose of IV fenoldopam. This study sought to determine whether compared with IV administration, selective intrarenal (IR) fenoldopam would increase local concentration, leading to a higher glomerular filtration rate (GFR), and, because of first-pass renal elimination, result in lower systemic drug levels and less decrease in systemic blood pressure (BP). A randomized, controlled, open-label, partial crossover design trial was conducted in which 33 patients who underwent coronary angiography were randomized in a 1:2 ratio to control or fenoldopam (initially IV, then crossed over to IR through a bifurcated renal infusion catheter). Compared with IV fenoldopam, IR administration was associated with a significantly higher GFR (73.7 +/- 3.1 vs 62.6 +/- 2.5 ml/min, p = 0.0007) and renal plasma flow (537.2 +/- 34.0 vs 494.0 +/- 35.5 ml/min, p0.01), lower fenoldopam plasma levels (3.3 +/- 0.3 vs 4.8 +/- 0.3 ng/ml, p0.0001), and greater nadir systolic BP (125.5 +/- 3.6 vs 117.4 +/- 2.8 mm Hg, p0.0001). Two hours after drug discontinuation after contrast administration, GFRs in the patients who received IR fenoldopam remained higher than in controls (+15.0 ml/min [+25%] vs -8.0 ml/min [-14.0%], p0.05). In conclusion, this pilot trial demonstrates that the IR infusion of fenoldopam is safe and practical, producing greater renal effect and less reduction of BP than IV infusion. It would be appropriate to restudy this renal vasodilator for the prevention of contrast nephropathy, using selective IR delivery.

Objectives This study was performed to evaluate the clinical and serial angiographic outcomes of patients undergoing sirolimus-eluting stent (SES) implantation for unprotected left main coronary artery (LMCA) stenosis. Background The efficacy of SES has led to their expanded use for off-label indications, including LMCA disease. Methods Unprotected LMCA intervention with SES was attempted in 50 patients. Surveillance angiography was performed at three and nine months’ follow-up. Results The target lesion involved the distal LMCA in 47 patients (94%). In-lesion restenosis occurred in 21 patients (42%), was focal in 85% of cases, and in 82% involved the branch ostia, sparing the LMCA itself. Target lesion revascularization (TLR) occurred in 19 patients (38%) over a mean follow-up of 276 ± 57 days; TLR was ischemia-driven in 7 patients (14%). Late loss was significantly greater within the left circumflex (LCX) ostium compared to the parent vessel (PV) of the LMCA bifurcation (0.83 ± 0.89 mm vs. 0.49 ± 0.72 mm, p = 0.04). Late loss continued to increase between three- and nine-month follow-up. Final minimal luminal diameter and maximal balloon pressure were independent predictors of restenosis of the PV. Conclusions Restenosis is a frequent finding when serial angiographic follow-up is performed after SES implantation for unprotected distal LMCA lesions. Restenosis is usually focal, most often involves the LCX ostium, and often occurs without symptoms.

Objectives These studies were conducted to evaluate the feasibility of percutaneous left atrial appendage (LAA) occlusion using the PLAATO system (ev3 Inc., Plymouth, Minnesota). Background Patients with atrial fibrillation (AF) have a five-fold increased risk for stroke. Other studies have shown that more than 90% of atrial thrombi in patients with non-rheumatic AF originate in the LAA. Transvenous closure of the LAA is a new approach in preventing embolism in these patients. Methods Within two prospective, multi-center trials, LAA occlusion was attempted in 111 patients (age 71 ± 9 years). All patients had a contraindication for anticoagulation therapy and at least one additional risk factor for stroke. The primary end point was incidence of major adverse events (MAEs), a composite of stroke, cardiac or neurological death, myocardial infarction, and requirement for procedure-related cardiovascular surgery within the first month. Results Implantation was successful in 108 of 111 patients (97.3%, 95% confidence interval [CI] 92.3% to 99.4%) who underwent 113 procedures. One patient (0.9%, 95% CI 0.02% to 4.9%) experienced two MAEs within the first 30 days: need for cardiovascular surgery and in-hospital neurological death. Three other patients underwent in-hospital pericardiocentesis due to a hemopericardium. Average follow-up was 9.8 months. Two patients experienced stroke. No migration or mobile thrombus was noted on transesophageal echocardiogram at one and six months after device implantation. Conclusions Closing the LAA using the PLAATO system is feasible and can be performed at acceptable risk. It may become an alternative in patients with AF and a contraindication for lifelong anticoagulation treatment.

The purpose of this study was to evaluate the clinical outcome of patients undergoing sirolimus-eluting stent implantation for de novo lesions within saphenous vein grafts (SVGs). Although the incidence of restenosis following sirolimus-eluting stenting (SES) of native coronary arteries is low, the efficacy of SES to treat de novo lesions within SVGs has not been well studied. A total of 35 patients underwent SES implantation of 39 lesions during 36 procedures. All patients had a minimum follow-up of 6 months following the index procedure. The mean bypass graft age was 10.1 +/- 6.5 years (range, 0-23 years). In-hospital major adverse cardiac events [death, myocardial infarction, thrombosis, or target vessel revascularization (TVR)] occurred in four patients (11%). Clinical follow-up was obtained in 100% of patients (mean follow-up, 7.5 +/- 2.2 months). There was one cardiac death, presumed due to stent thrombosis. TVR occurred in only two patients (6%). Myocardial infarction (MI) occurred in four patients (11%), all attributable to a nontarget vessel. The combined endpoint of death, MI, or TVR occurred in seven patients (20%). Freedom from death, nonfatal MI, thrombosis, or any revascularization was 65%. Early experience indicates sirolimus-eluting stents for de novo saphenous vein graft lesions have a low (6%) rate of clinically driven target vessel revascularization. By 7-month follow-up, event-free survival is limited primarily by disease in nontarget vessels.

The Washington Radiation for In-Stent Restenosis Trial in Saphenous Vein Grafts (SVG WRIST) demonstrated safety and efficacy of intravascular radiation therapy (IRT) for the treatment of in-stent restenosis (ISR) in SVG at 12 months. In this study, we aimed to examine whether the safety and efficacy of IRT is durable up to 36 months. One hundred twenty patients with diffuse ISR in SVG underwent balloon angioplasty, laser or atherectomy ablation, and/or additional stenting. After successful intervention, patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium (Ir)-192 (n = 60) or nonradioactive seeds (n = 60). The prescribed dose at 2 mm from the source was either 14 or 15 Gy in vessels 2.5-4.0 mm or 18 Gy in vessels > 4.0 mm in diameter. At 36 months, target lesion revascularization (TLR; 43% vs. 66%; P = 0.02) and target lesion revascularization-major adverse cardiac event (TLR-MACE; 49% vs. 71%; P = 0.02) rates continued to be lower in the IRT group, but both target vessel revascularization (TVR; 59% vs. 71%; P = 0.17) and TVR-MACE (63% vs. 77%; P = 0.11) rates were not. In SVG WRIST, patients with ISR treated with IRT had a marked reduction in the need for repeat TLR at 36 months, with sustained clinical benefit at 3 years despite late recurrences, which were more pronounced in the radiation group.

In Part I of this article, the definitions, prevalence, and clinical presentation of chronic total occlusions (CTOs) were reviewed, the histopathology of CTOs was examined, efforts to replicate human CTOs with experimental models were appraised, and the clinical relevance and rationale for CTO revascularization were evaluated.1 In Part II, we summarize the technical approach to and outcomes after percutaneous coronary intervention (PCI) of occluded coronary arteries, describe the novel devices and drugs approved and undergoing investigation for CTO recanalization, and conclude with practical perspectives on managing the patient with 1 or more chronic coronary occlusions. ### Patient Selection and Revascularization Strategies PCI of CTOs constitutes as many as 20% of all angioplasty procedures at selected centers,2 although a rate of &10% is more typical,3–6 suggesting that CTO angioplasty is attempted in 50 000 to 100 000 patients per year in the United States. Many more CTOs are present for which PCI is never attempted, representing one of the most common causes for referral to bypass surgery rather than PCI.6–8 Furthermore, a large proportion of patients with CTOs are managed medically, the prognosis of whom may vary depending on the extent of viable myocardium and ischemia, concomitant atherosclerosis in other coronary and noncoronary vascular territories, and other comorbid conditions. The decision to attempt PCI of a CTO (versus continued medical therapy or surgical revascularization) requires an individualized risk/benefit analysis, encompassing clinical, angiographic, and technical considerations. Clinically, the patient’s age, symptom severity, associated comorbidities (eg, diabetes mellitus and chronic renal insufficiency), and overall functional status are major determinants of treatment strategy. Angiographically, the extent and complexity of coronary artery disease (eg, single-vessel versus multivessel disease, single versus multiple total occlusions, likelihood for complete revascularization), left ventricular function, and the presence and degree of valvular heart disease should be considered. The technical probability of achieving …

Background— Revascularization strategies often hinge on the presence and degree of left anterior descending coronary artery (LAD) stenosis. A decision for bypass surgery is often based on the durability of surgical LAD revascularization compared with percutaneous approaches. By decreasing restenosis, drug-eluting stents may have reduced the “reintervention gap” between surgery and percutaneous intervention, making the percutaneous route preferable. Methods and Results— Of the 1101 patients in the SIRIUS trial, 459 with an LAD stenosis were randomized to percutaneous intervention with either sirolimus-eluting or bare-metal stents. Baseline demographic, clinical, and angiographic data were obtained. Patients had 1-year clinical and 8-month angiographic follow-up. Baseline characteristics were similar in both groups. The majority of lesions were tubular type B lesions (69.7%) with a mean diameter of 2.73 mm and a mean length of 14.0 mm. The binary in-stent restenosis rate was 2% for the sirolimus stent group and 41.6% for the bare-metal arm (relative risk, 0.05; 95% CI, 0.02 to 0.1; P P P =NS). Conclusions— Sirolimus-eluting stents significantly decrease revascularization rates in LAD lesions. At 1 year, sirolimus-eluting stent revascularization rates are comparable to historic single vessel bypass surgery revascularization rates.

A 78-year-old man is admitted with episodes of severe angina associated with hypotension. Urgent angiography finds critical left main stenosis with well-preserved left ventricular function (Figure 1). While discussing the treatment plan with the physician, the patient suddenly manifests sustained ventricular fibrillation. Prompt electrocardioversion restores sinus rhythm, but there is electromechanical dissociation and no blood pressure. Chest compressions are initiated. A guiding catheter quickly inserted into the left coronary finds total occlusion of the left main (Figure 2). Between chest compressions, the left main is opened with balloon angioplasty (Figure 3), and a stent is implanted, restoring flow, contractility, and blood pressure. The patient is discharged 3 days later, sustaining only a small rise in cardiac enzymes. Figure 1. Urgent coronary angiography in a 78-year-old man with unstable angina finds critical left main stenosis (A). Figure 2. The left main occludes soon after the diagnostic angiogram, resulting in absent ventricular contraction. Figure 3. Emergency balloon angioplasty during cardiopulmonary resuscitation improves left main flow (note wrist watch on individual performing cardiopulmonary resuscitation at right upper corner of image). A DES is then implanted. See p 1942 and p 1948 Is this case unusual? Some might argue “no.” Stents and balloon angioplasty have been used for decades to rescue patients from disaster. However, in one way, this 78-year-old man underwent a revolutionary procedure. This patient’s left main coronary artery was treated with a drug-eluting stent (DES). Three months later, a follow-up angiogram found no evidence of restenosis (Figure 4). If further follow-up of this and other patients enrolled in left main DES trials prove favorable, the paradigm could shift, making DES the treatment of choice for obstructive left main coronary disease. Figure 4. Surveillance angiogram at 3 months documents excellent patency of the DES within the left main coronary artery. In the …

The management of diabetic patients with restenosis after percutaneous coronary intervention remains a significant challenge. Diabetic patients remain at significant risk of restenosis despite stent implantation. This retrospective analysis was performed to determine the extent to which vascular brachytherapy improves late clinical and angiographic outcomes in diabetic patients compared to conventional therapy and compared to patients' nondiabetic counterparts.Pooled data from two studies (START [Stents and Radiation Trial] and START-40 trials) of patients (204 diabetic, 477 nondiabetic) receiving vascular brachytherapy (VBT) with a (90)Sr/(90)Y source after conventional percutaneous coronary intervention for in-stent restenosis comprise the study population. The radiation delivery system used in both studies was the Beta-Cath system. The prescribed dose at 2 mm from the centerline of the source axis was 18.4 Gy or 23 Gy, depending on vessel diameter. The reference vessel diameter, minimal lumen diameter, and percent diameter stenosis were measured before the intervention, at the conclusion of the procedure, and at the 8-month follow-up examination. The Breslow-Day test was used to formally assess the similarity of treatment effect between diabetic and nondiabetic patients.Target lesion and target vessel revascularization rates and angiographic restenosis rates in diabetic and nondiabetic patients treated with beta radiation or placebo were analyzed. Diabetic patients were more likely to have longer and more complex coronary lesions. In-hospital outcomes in diabetic and nondiabetic patients were similar, irrespective of treatment status. At 8 months, patients treated with beta radiation exhibited less target lesion revascularization (diabetic: 10.9% vs. 22.7%, p = 0.02; nondiabetic: 12.8% vs. 22.3%, p = 0.007) and less target vessel revascularization (diabetic: 14.7% vs. 25.3%, p = 0.06; nondiabetic: 16.6% vs. 23.6%, p = 0.06) compared to placebo. In-stent binary angiographic restenosis was lower in irradiated patients (diabetic: 19.4% vs. 37.3% for placebo, p = 0.01; nondiabetic: 12.9% vs. 43% for placebo, p0.001). However, restenosis beyond the stent site reduced the impact of VBT, regardless of diabetic status. The magnitude of the treatment effect for target lesion and target vessel revascularization rates was similar between diabetic and nondiabetic patients.Previously published institutional experiences have suggested that diabetic patients benefit from the use of VBT in the management of in-stent restenosis. This analysis now provides direct evidence to support the role of beta radiation VBT in this patient population. Diabetic patients undergoing this therapy are just as likely to benefit from it as their nondiabetic counterparts.

Transplant vasculopathy significantly limits the survival of cardiac transplant patients and occurs in 50% of patients by 5 years posttransplant. We report our experience with six cardiac transplant patients who underwent intracoronary brachytherapy for in-stent restenosis. At four centers, six patients underwent intracoronary radiation for in-stent restenosis. All patients received extended antiplatelet therapy with clopidogrel and aspirin. Follow-up angiography was performed in all patients. Two of the six patients underwent subsequent target lesion revascularization. Patient 1 presented with total occlusion of her radiated lesion. She had a complex procedure requiring stenting for a dissection after the radiation dwell. Patient 2 had high-grade restenosis following brachytherapy. Patient 3 had a 50% restenotic lesion. Patients 4, 5, and 6 had follow-up angiography that showed no evidence of restenosis. There are few good options to treated accelerated transplant vasculopathy. Radiation therapy may be a viable option in this difficult patient population.

OBJECTIVES We analyzed the effects of vascular brachytherapy (VBT) on ostial in-stent restenosis (ISR). BACKGROUND In-stent restenosis has a high recurrence rate after percutaneous reintervention. The recurrence rate of ostial ISR lesions and the impact of VBT remain unknown. METHODS We evaluated 133 patients with native coronary ostial ISR from a pooled database of 990 patients enrolled in randomized VBT trials. Independent quantitative angiography was performed at baseline and follow-up in 45 gamma, 27 beta, and 61 placebo patients. RESULTS Binary restenosis was significantly higher in placebo than radiated patients (75.4% vs. 17.8% in gamma vs. 22.2% in beta, p < 0.0001). The treatment effect of both gamma (odds ratio [OR] 0.06; 95% confidence interval [CI] 0.02 to 0.17) and beta VBT (OR 0.10; 95% CI 0.03 to 0.31) was maintained after controlling for differences in baseline lesion length. Proximal and distal radiation edge restenosis rates were similar among the groups. Vascular brachytherapy of true aorto-ostial lesions (n = 34) was similarly beneficial: restenosis rates of placebo versus gamma or beta patients of 83.3% versus 6.7% versus 28.6%, p = 0.0002. CONCLUSIONS Conventional treatment of ostial ISR is associated with a recurrence rate of over 75%. Vascular brachytherapy with either gamma or beta sources results in significant and similar reductions in restenosis compared with placebo. Similar benefits after VBT prevail in true aorto-ostial lesions.

Background Therapy with either low-molecular-weight heparin (LMWH) or glycoprotein (GP) IIb/IIIa receptor antagonists is of benefit to patients with acute coronary syndromes (ACSs). However, algorithms that define how LMWH may be used in patients, proceeding from medical management to intervention and in conjunction with GP IIb/IIIa inhibitors, are lacking. The objectives of this task force were to formulate recommendations based on all available data for the use of LMWH, both with and without GP IIb/IIIa receptor antagonists, and to provide seamless integration of care during the transition from medical to interventional management. Methods and Results An international task force of 14 cardiologists with extensive experience in clinical trials was convened in New York in February 2001 to address issues related to the use of LMWH in patients with non-ST-elevation ACS. Evidence from randomized trials, observational studies, and other reports was discussed, and consensus recommendations were formulated. Conclusions Substantial evidence exists that patients receiving LMWH for an ACS can safely undergo cardiac catheterization and percutaneous coronary intervention. Concerns regarding the transition of these patients from the medical service to the cardiac catheterization laboratory should therefore not impede the upstream use of LMWH. Furthermore, LMWH and GP IIb/IIIa receptor antagonists can be used safely in combination, with no apparent increase in the risk of major bleeding. Consensus algorithms for therapy are presented. (Am Heart J 2002;144:615-24.)

Background — Recently, several randomized trials have demonstrated that intracoronary brachytherapy can reduce the rates of both angiographic and clinical restenosis in patients undergoing percutaneous coronary intervention (PCI) for in-stent restenosis. Whether this practice is cost-effective is unknown. Methods and Results — Between December 1997 and July 1998, 252 patients with in-stent restenosis were randomized to receive brachytherapy or placebo after successful PCI as part of the Gamma-1 trial. We collected detailed resource utilization and cost data for each patient’s initial hospitalization and for 1 year after randomization. Compared with conventional treatment, intracoronary brachytherapy increased procedure duration, physician services, and equipment costs. As a result, initial costs were increased by nearly $4100 per patient ($15 724 versus $11 675, P P =0.46). In a sensitivity analysis that incorporated recent technical modifications and the use of prolonged antiplatelet therapy to prevent late thrombotic occlusion, follow-up cost savings increased to $3600/patient, and 1-year costs were slightly lower with brachytherapy ($26 352 versus $26 729, P =0.87). Subgroup analysis demonstrated significant cost savings in patients with diabetes and patients who did not undergo repeat stenting. Conclusions — As performed in the Gamma-1 trial, coronary brachytherapy for in-stent restenosis improved clinical outcomes but increased 1-year costs compared with standard therapy. If late thrombosis can be eliminated, however, this technology has the potential to reduce overall medical care costs.

Background — Several clinical trials indicate that intracoronary radiation is safe and effective for treatment of restenotic coronary arteries. We previously reported 6-month and 3-year clinical and angiographic follow-up demonstrating significant decreases in target lesion revascularization (TLR) and angiographic restenosis after γ radiation of restenotic lesions. The objective of this study was to document the clinical outcome 5 years after treatment of restenotic coronary arteries with catheter-based iridium-192 ( 192 Ir). Methods and Results — A double-blind, randomized trail compared 192 Ir to placebo sources in patients with restenosis after coronary angioplasty. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192 Ir and 29 to placebo. At 5-year follow-up, TLR was significantly lower in the 192 Ir group (23.1% versus 48.3%; P =0.05). There were 2 TLRs between years 3 and 5 in patients in the 192 Ir group and none in patients in the placebo group. The 5-year event-free survival rate (freedom from death, myocardial infarction, or TLR) was greater in 192 Ir-treated patients (61.5% versus 34.5%; P =0.02). Conclusions — Despite apparent mitigation of efficacy over time, there remains a significant reduction in TLR at 5 years and an improvement in event-free survival in patients treated with intracoronary 192 Ir. The early clinical benefits after intracoronary γ radiation with 192 Ir seem durable at 5-year clinical follow-up.

OBJECTIVES We sought to evaluate the safety and efficacy of percutaneous transmyocardial revascularization (PTMR) in patients with refractory angina caused by one or more chronic total occlusions (CTOs) of a native coronary artery. BACKGROUND Previous unblinded, randomized trials of PTMR in patients with end-stage coronary artery disease and refractory angina have demonstrated significant relief of angina and increased exercise duration. Whether such benefits would be realized in blinded patients with less extensive coronary artery disease is unknown. METHODS A total of 141 consecutive patients with class III or IV angina caused by one or more chronically occluded native coronary arteries in which a percutaneous coronary intervention (PCI) had failed were prospectively randomized, at 17 medical centers, in the same procedure, to PTMR plus maximal medical therapy (MMT) (n = 71) or MMT only (n = 70). Blinding was achieved through heavy sedation, dark goggles and the concurrent performance of PCI in all patients. RESULTS Baseline characteristics were similar between the two groups. A median number of 20 laser channels were created in patients randomized to PTMR. At six months, the anginal class improved by two or more classes in 49% of patients assigned to PTMR and in 37% of those assigned to MMT (p = 0.33). The median increase in exercise duration from baseline to six months was 64 s with PTMR versus 52 s with MMT (p = 0.73). There were no differences in the six-month rates of death (8.6% vs. 8.8%), myocardial infarction (4.3% vs. 2.9%) or any revascularization (4.3% vs. 5.9%) in the PTMR and MMT groups, respectively (p = NS for all). CONCLUSIONS In patients with class III or IV angina caused by nonrecanalizable CTOs, the performance of PTMR does not result in a greater reduction in angina, improvement in exercise duration or survival free of adverse cardiac events, as compared with MMT only.

Intracoronary radiation therapy is effective in reducing the recurrence of in-stent stenosis in native coronary arteries. We examined the effects of intravascular gamma radiation in patients with in-stent restenosis of saphenous-vein bypass grafts.A total of 120 patients with in-stent restenosis in saphenous-vein grafts, the majority of whom had diffuse lesions, underwent balloon angioplasty, atherectomy, additional stenting, or a combination of these procedures. If the intervention was successful, the patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium-192 or nonradioactive seeds. The prescribed dose, delivered at a distance of 2 mm from the source, was 14 to 15 Gy in vessels that were 2.5 to 4.0 mm in diameter and 18 Gy in vessels with a diameter that exceeded 4.0 mm. The primary end points were death from cardiac causes, Q-wave myocardial infarction, revascularization of the target vessel, and a composite of these events at 12 months.Revascularization and radiation therapy were successfully accomplished in all patients. At six months, the restenosis rate was lower in the 60 patients assigned to the iridium-192 group than in the 60 assigned to the placebo group (21 percent vs. 44 percent, P=0.005). At 12 months, the rate of revascularization of the target lesion was 70 percent lower in the iridium-192 group than in the placebo group (17 percent vs. 57 percent, P0.001), and the rate of major cardiac events was 49 percent lower (32 percent vs. 63 percent, P0.001).The results of our study support the use of gamma-radiation therapy for the treatment of in-stent restenosis in patients with bypass grafts.

The Scripps Trial was a randomized study of intracoronary artery radiation therapy with iridium 192 used to treat restenotic vessels. We used the intravascular ultrasound data from the Scripps Trial to investigate whether a lumen-centered gamma or beta radiation source would reduce radiation dose heterogeneity compared with the noncentered source position used.Analysis included 28 patients with stent placement in 20 native vessels and 8 saphenous vein grafts enrolled in this trial. Radiation dosimetry for gamma radiation was calculated to deliver 800 cGy to the far field target, provided the maximum dose to the near field target did not exceed 3000 cGy. Prescribed dosimetry for beta radiation by use of yttrium 90 was 1600 cGy at 2 mm distance from the source.The calculated average minimum source to target distance by use of a lumen-centered source increased by 0.18 mm from 1.70 +/- 0.25 to 1.88 +/- 0.36 mm, whereas the maximum distance decreased by 0.17 mm from 3.64 +/- 0.60 to 3.47 +/- 0.43 mm (P.05). On the basis of these distances, the maximum radiation dose, as well as radiation dose heterogeneity (ratio of maximum to minimum), would have been reduced in 22 of 28 patients by use of a lumen-centered gamma or beta source (P.005). The reduction in dose heterogeneity was substantially greater with a beta source compared with a gamma source (48% vs 16% reduction).Centering of the intracoronary artery radiation therapy delivery catheter within the vessel lumen can significantly reduce radiation dose heterogeneity when compared with a noncentered source position. This dose reduction is substantially greater for a beta compared with a gamma source.

Long-term clinical outcomes after exposure to non-ionic iso-osmolar contrast medium (IOCM) or ionic low-osmolar CM (LOCM) in patients with chronic kidney disease (CKD) undergoing coronary angiography are unclear.The ICON trial was a prospective, double-blinded, multicentre study that randomly assigned 146 patients with CKD undergoing coronary angiography with or without percutaneous coronary intervention to the non-ionic IOCM Iodixanol or the ionic LOCM Ioxaglate. We report the 1-year clinical outcomes.After randomization, baseline and procedural characteristics were well-matched between the two groups. At 1 year, three deaths (4.1%) occurred in the ioxaglate and nine deaths in the iodixanol group (13.6%, P = 0.07). The cardiac death rate at 1 year was 2.7% in the ioxaglate group and 9.1% in the iodixanol group (P = 0.07). There were no significant differences in the rates of myocardial infarction (1.4% vs. 1.5%; P = 1.00) and repeated revascularization (6.8% vs. 9.1%; P = 0.75).The use of ionic LOCM ioxaglate was associated with a numerically lower mortality at 1 year as compared to iodixanol in patients who underwent cardiac catheterization. Future studies evaluating long-term safety following exposure to different types of CM are warranted.

This study sought to determine whether outcomes for transfemoral (TF) transcatheter aortic valve replacement (TAVR) differ between the randomized controlled trial (RCT) and the subsequent NRCA (Nonrandomized Continued Access) registry of the PARTNER (Placement of AoRTic TraNscathetER Valves) trial.The PARTNER RCT demonstrated that TAVR with the Edwards Sapien valve (Edwards Lifesciences, Irvine, California) is noninferior to surgery in high-risk patients and superior to standard therapy for inoperable patients.The inclusion and exclusion criteria, data collection, monitoring, and core laboratories were the same for the RCT and NRCA registry. Baseline characteristics, procedural results, and 1-year outcomes were compared between patients undergoing TF-TAVR as part of the RCT and as part of the NRCA registry.In the RCT, 415 patients underwent TF-TAVR, whereas in the NRCA, 1,023 patients did. At 30 days, death, cardiac death, stroke, and transient ischemic attacks were not different in the NRCA registry than in the RCT. Major vascular complications (8.0% vs. 15.7%, p 0.0001) and major bleeding (6.8% vs. 15.3%, p 0.0001) were significantly lower in the NRCA registry. At 1 year, death rates were significantly lower in the NRCA cohort (19.0% vs. 25.3%, p = 0.009) and cardiac death tended to be lower (8.4% vs. 11.1%, p = 0.12). Stroke or transient ischemic attack (6.2% vs. 8.7%, p = 0.10) and stroke alone (5.0% vs. 7.1%, p = 0.13) also tended to be lower.The large NRCA registry demonstrates further improvement in procedural and longer-term outcomes after TF-TAVR when compared with the favorable results from the PARTNER RCT. (THE PARTNER TRIAL: Placement of AoRTic TraNscathetER Valve Trial; NCT00530894).

To report 1- and 2-year clinical outcomes of patients receiving platinum chromium everolimus-eluting stents (PtCr-EES) in the prospective, single-arm PLATINUM small vessel (SV) and long lesion (LL) studies.Small vessel diameter and long lesion length are independently associated with increased risk of adverse cardiac events after drug-eluting stent implantation.The PLATINUM SV study enrolled 94 patients with coronary artery lesions in vessels ≥2.25 mm to2.50 mm in diameter and ≤28 mm in length. The PLATINUM LL study enrolled 102 patients with lesions24 to ≤34 mm long in vessels ≥2.50 to ≤4.25 mm in diameter. The primary endpoint for both studies was target lesion failure (TLF) at 1 year compared to a prespecified performance goal based on outcomes with the TAXUS Express paclitaxel-eluting stent in small vessels and long lesions.One-year TLF rates with the PtCr-EES were significantly (P0.001) lower than the predetermined performance goals: 2.4% versus 21.1% in the SV cohort and 3.2% versus 19.4% in the LL cohort. Cumulative rates of TLF to 2 years were 4.7% in the SV cohort and 8.8% in the LL cohort. No myocardial infarction or ARC definite/probable stent thromboses occurred in either cohort through 2-year follow-up.The clinical efficacy and safety outcomes observed in these small vessel and long lesion cohorts support the use of the PtCr-EES in the treatment of small diameter vessels and long lesions.

OBJECTIVESWe performed a multicenter, double-blind placebo-controlled trial to examine the efficacy and safety of enoxaparin in patients at high risk for stent thrombosis (ST).BACKGROUNDThe optimal antithrombotic regimen for such patients is unknown.METHODSWe randomized 1,102 patients with clinical, angiographic or ultrasonographic features associated with an increased risk of ST to receive either twice-daily injections of weight-adjusted enoxaparin or placebo for 14 days after stenting. All patients received aspirin and ticlopidine. The primary end point was a 30-day composite end point of death, myocardial infarction (MI) or urgent revascularization.RESULTSThe target enrollment for the study was 2,000 patients. However, the trial was terminated prematurely at 1,102 patients after interim analysis revealed an unexpectedly low event rate. The primary outcome occurred in 1.8% enoxaparin-treated patients versus 2.7% treated with placebo (odds ratio [OR] 0.66; 95% confidence interval [CI] 0.29 to 1.5, p = 0.30); for death or MI the rates were 0.9% vs. 2.2%, respectively (OR 0.41, 95% CI 0.14 to 1.2, p =0.13); and for MI, 0.4% vs. 1.6%, respectively (OR 0.22, 95% CI 0.05 to 0.99, p = 0.04). The groups had comparable rates of major bleeding (3.3% for enoxaparin, 1.6% for placebo, p =0.08), but minor nuisance bleeding was increased with enoxaparin (25% vs. 5.1%, p < 0.001).CONCLUSIONSThe clinical outcomes of patients at increased risk of ST are more favorable than previously reported, rendering routine oral antiplatelet therapy adequate for most. However, given its relative safety and potential to reduce the risk of subsequent infarction, a 14-day course of enoxaparin may be considered for carefully selected patients.

Background —The optimal level of platelet inhibition with a glycoprotein (GP) IIb/IIIa antagonist necessary to minimize thrombotic complications in patients undergoing a percutaneous coronary intervention (PCI) is currently unknown. Methods and Results —Five hundred patients undergoing a PCI with the planned use of a GP IIb/IIIa inhibitor had platelet inhibition measured at 10 minutes, 1 hour, 8 hours, and 24 hours after the initiation of therapy with the Ultegra Rapid Platelet Function Assay (Accumetrics). Major adverse cardiac events (MACEs: composite of death, myocardial infarction, and urgent target vessel revascularization) were prospectively monitored, and the incidence correlated with the measured level of platelet function inhibition at all time points. One quarter of all patients did not achieve ≥95% inhibition 10 minutes after the bolus and experienced a significantly higher incidence of MACEs (14.4% versus 6.4%, P =0.006). Patients whose platelet function was P =0.009). By multivariate analysis, platelet function inhibition ≥95% at 10 minutes after the start of therapy was associated with a significant decrease in the incidence of a MACE (odds ratio 0.46, 95% CI 0.22 to 0.96, P =0.04). Conclusions —Substantial variability in the level of platelet function inhibition is achieved with GP IIb/IIIa antagonist therapy among patients undergoing PCI. The level of platelet function inhibition as measured by a point-of-care assay is an independent predictor for the risk of MACEs after PCI.

OBJECTIVES We sought to investigate the in vivo mechanical properties of a new self-expanding coronary stent (RADIUS) and, particularly, the subsequent vessel response over time. BACKGROUND Preclinical studies have suggested that self-expanding stents may produce less vessel wall injury at initial deployment, leading to larger follow-up lumens than with balloon-expandable stents. However, the influence of the chronic stimulus from self-expanding stents on the vessel wall remains unknown. METHODS Sixty-two patients were randomly assigned to either the RADIUS self-expanding stent group (n = 32) or the Palmaz-Schatz balloon-expandable stent group (n = 30). Intravascular ultrasound was performed after stent deployment and at six-month follow-up. RESULTS At follow-up, the RADIUS stents had increased 23.6% in overall volume, while the Palmaz-Schatz stents had remained unchanged. Due to the greater mean neointimal area (3.0 ± 1.7 mm2vs. 1.9 ± 1.2 mm2, p = 0.02) in the RADIUS group, no significant difference in net late lumen loss was observed between the two groups. On the other hand, analysis at the peristent margins demonstrated that mean late loss was significantly smaller in the RADIUS group than it was in the Palmaz-Schatz group (0.1 ± 2.1 mm2vs. 1.9 ± 2.4 mm2, p = 0.02). CONCLUSIONS Serial volumetric IVUS revealed that the RADIUS stents continued to enlarge during the follow-up period. In this stent implantation protocol, this expansion was accompanied by a greater amount of neointima than the Palmaz-Schatz stents, resulting in similar late lumen loss in both configurations. In the peristent margins, however, late lumen loss was minimized with the RADIUS stents.

Angiographic restenosis occurs in 30% to 50% of patients after percutaneous transluminal coronary angioplasty (PTCA) with 20% to 30% target vessel revascularization at one year, and is associated with increased morbidity, mortality and health care costs. Intracoronary stents are the first line of therapy against restenosis after angioplasty. Depending on lesion morphology and location, stents can reduce restenosis and target lesion revascularization (TLR) by 20% to 30%. Obstructive coronary lesions in vessels with a diameter larger than 3.0 mm should be stented. The benefit of stenting in vessels smaller than 3.0 mm is controversial, with the BESMART (Bestent in Small Arteries) and ISAR-SMART (Intracoronary Stenting or Angioplasty for Restenosis Reduction in Small Arteries) studies demonstrating conflicting results. Chronically occluded and subtotal vessels should be stented after PTCA. Obstructive lesions in saphenous vein grafts should be stented. It is preferable to stent ostial lesions after PTCA. Restenosis can occur in 15% to 25% of patients within 6 months of stent placement. Initial approach to focal in-stent restenosis is to repeat PTCA. Patients with diffuse restenosis may require debulking prior to PTCA to improve acute results. "Stenting within-stent" has not proven beneficial unless there is diffuse in-stent restenosis, neointimal prolapse or vessel dissection during PTCA. There are no pharmacologic therapies approved by the Food and Drug Administration available to treat restenosis at present. Brachytherapy, gamma or beta, is an effective adjunctive therapy that can reduce recurrent in-stent restenosis by 40% to 70%. Patients at high risk for recurrent in-stent restenosis (proliferative or total occlusion pattern) can be considered for brachytherapy to treat the first episode of in-stent restenosis. Patients with focal in-stent restenosis should be treated with brachytherapy after multiple recurrences of in-stent restenosis. Emerging therapies for treatment of restenosis include antiproliferative-coated stents and photoangioplasty.

Although the frequency of restenosis after coronary angioplasty is reduced by stenting, when restenosis develops within a stent, the risk of subsequent restenosis is greater than 50 percent. We report on a multicenter, double-blind, randomized trial of intracoronary radiation therapy for the treatment of in-stent restenosis.Of 252 eligible patients in whom in-stent restenosis had developed, 131 were randomly assigned to receive an indwelling intracoronary ribbon containing a sealed source of iridium-192, and 121 were assigned to receive a similar-appearing nonradioactive ribbon (placebo).The primary end point, a composite of death, myocardial infarction, and the need for repeated revascularization of the target lesion during nine months of follow-up, occurred in 53 patients assigned to placebo (43.8 percent) and 37 patients assigned to iridium-192 (28.2 percent, P=0.02). However, the reduction in the incidence of major adverse cardiac events was determined solely by a diminished need for revascularization of the target lesion, not by reductions in the incidence of death or myocardial infarction. Late thrombosis occurred in 5.3 percent of the iridium-192 group, as compared with 0.8 percent of the placebo group (P=0.07), resulting in more late myocardial infarctions in the iridium-192 group (9.9 percent vs. 4.1 percent, P=0.09). Late thrombosis occurred in irradiated patients only after the discontinuation of oral antiplatelet therapy (with ticlopidine or clopidogrel) and only in patients who had received new stents at the time of radiation treatment.Intracoronary irradiation with iridium-192 resulted in lower rates of clinical and angiographic restenosis, although it was also associated with a higher rate of late thrombosis, resulting in an increased risk of myocardial infarction. If the problem of late thrombosis within the stent can be overcome, intracoronary irradiation with iridium-192 may become a useful approach to the treatment of in-stent restenosis.

We report treatment of a lesion with coronary stent underexpansion due to heavily calcified plaque. Conventional balloon angioplasty was attempted for in-stent restenosis, but the lesion was undilatable despite 25-atm inflation pressure. Intravascular ultrasound (IVUS) revealed stent underexpansion due to heavily calcified plaque. Rotational atherectomy was performed using a stepped burr approach, after which repeat IVUS revealed marked ablation of the stent-calcium complex. Adjunctive balloon angioplasty then easily resulted in full balloon and stent expansion, with an excellent angiographic and IVUS result. The patient's hospital course was uneventful.

Background —The aim of this study was to use serial volumetric intravascular ultrasound to evaluate the effect of γ-radiation on recurrent in-stent restenosis. Methods and Results —After successful reintervention, patients were randomized to receive either 192 Ir or placebo. Intravascular ultrasound studies with motorized pullback (0.5 mm/s) were performed immediately after irradiation and at 8-month follow-up in 70 patients. Paired volumetric analysis of the stented segment and of 5-mm proximal and distal reference segments was performed; this included measurements of the external elastic membrane, lumen, plaque and media (external elastic membrane minus lumen), stent, and intimal hyperplasia (stent minus lumen). Baseline proximal reference, stent, and distal reference measurements were similar in both groups. The changes in proximal and distal reference measurements of the external elastic membrane, plaque and media, and lumen areas were similar in both groups. However, the decrease in stented segment lumen volume was less in the 192 Ir patients than the placebo patients (–25±34 mm 3 versus –48±42 mm 3 ; P =0.0225), and the increase in the volume of intimal hyperplasia in the stented segment was less in the 192 Ir patients than in the placebo patients (28±37 mm 3 versus 50±40 mm 3 ; P =0.0352). When averaged over the length of the stented segment (32±13 mm versus 33±14 mm; P =0.9), the increase in mean area of intimal hyperplasia was 0.8±1.0 mm 2 in the 192 Ir group and 1.6±1.2 mm 2 in the control group ( P =0.0065). Late stent-vessel wall malapposition was noted in one placebo patient and no 192 Ir patients. Conclusions —γ-Radiation therapy can effectively prevent recurrent in-stent restenosis by inhibiting neointimal formation within the stent. At the stent edge, there were no significant differences between 192 Ir and placebo patients.

Purpose: In this study, the effect of barotrauma due to stent deployment is investigated for several commonly used commercial stents used in endovascular brachytherapy for restenosis prevention. Methods and Materials: Restenosis due to intimal hyperplasia can occur anywhere along the clinical target volume, which is defined as the length of vessel receiving intervention or injury. The injury may be due to angioplasty, atherectomy (tissue removing), stenting, and stent deployment. Manufacturer specifications for several commonly used stents were reviewed and the results were tabulated. Results: The barotrauma length of stents reviewed in this study ranges from 0.5 to 2.5 mm; the average was 1.7 mm. Conclusions: By considering specific barotrauma into the treatment length, one can provide adequate treatment margins to minimize edge failure or to avoid "geographic miss," which may improve the efficacy of endovascular brachytherapy.

Distal embolization is a common complication of percutaneous intervention in saphenous vein grafts. This may lead to the no reflow phenomenon and subsequent myocardial infarction. We describe a case in which we occluded the distal portion of a saphenous vein graft with a balloon to prevent distal embolization, performed percutaneous transluminal coronary angioplasty, and then successfully aspirated the particulate debris with a Dorros/Probing catheter.

The International Commission on Radiation Units and Measurement (IRCU) 50 has clearly defined treatment volumes in radiation therapy in the management of neoplasms. These concepts are applied to the field of endovascular brachytherapy (EVBT) for the prevention of postangioplasty restenosis. The following definitions are proposed: gross target length (GTL) is defined as the narrowed segment of the artery that requires intervention. Clinical target length (CTL) is defined as the intervened or injured length, which could be due to angioplasty, stent strut injury, stent deployment, or debulking procedures. Planning target length (PTL) is the CTL plus a margin to account for heart/catheter movement and uncertainty in target localization. The final treatment length (TL) is the PTL plus the effect of penumbra. The accurate specification of treatment length serves several important purposes. Based on an understanding of the different factors constituting the treatment length, adequate margins can be provided beyond the GTL; this will avoid geographic misses and minimize edge failures. These definitions of target length ensure treatment consistency and provide a standard terminology for communication among practitioners of EVBT, something of critical importance in the conduct of multi-institutional trials in this new and multidisciplinary therapy. Finally, since the efficacy of EVBT is critically dependent on the precision of radiation delivery, these guidelines ensure that the benefits of EVBT seen in prospective randomized trials can be translated into daily clinical practice at the community level.

The BARASTER registry was formed to evaluate the initial success and long-term results of rotational atherectomy in the management of in-stent restenosis. Rotational atherectomy was used in 197 cases of in-stent restenosis: 46 with stand-alone rotational atherectomy or at most 1 atmosphere of balloon inflation (Rota strategy), and 151 with rotational atherectomy and adjunctive balloon angioplasty

To identify luminal dimension changes occurring within the stent alone and within the stent + margin segment, we reviewed the quantitative angiographic results obtained from the Scripps Coronary Radiation to Inhibit Proliferation Post Stenting (SCRIPPS) trial, a prospective randomized trial assessing the effect of iridium-192 (Ir-192) on the prevention of stent restenosis. Fifty-five patients were randomly assigned to receive Ir-192 or placebo sources after successful intervention. Procedural and 6-month follow-up cineangiograms were quantitatively reviewed in 52 patients to identify changes within the stent and the stent + margin segment. The percent diameter stenosis was lower within the stent than within the stent + margin segment after the procedure (6 +/- 22% vs 21+/- 15%, p0.0001) and at follow-up (28 +/- 29% vs 42 +/- 21%, p0.0001). As a result, a lower restenosis rate was found within the stent than within the stent + margin (25% vs 37%, p0.0001); isolated stent margin restenosis occurred in 11.5% of lesions. Treatment with Ir-192 reduced restenosis within the stent (8% vs 39%; p = 0.010) and within the stent + margin segment (17% vs 54%; p = 0.010); the reduction in restenosis at the margin only (8.3% vs 14.3%, p = 0.503) was not significant. The lowest relative risk for restenosis resulting from Ir-192 occurred within the stent (0.21; 95% confidence interval [CI] 0.05 to 0.86) compared with the stent + margin segment (0.31; 95% CI 0.12 to 0.81) or the stent margin (0.58; 95% CI 0.12 to 2.91). In the SCRIPPS trial, 32% of restenosis occurred at the stent margins. Treatment with Ir-192 reduced restenosis primarily within the stent rather than the margin. Whether extending the treatment length to fully include the stent margins will further reduce restenosis requires further study.

Purpose. Several prospective randomized clinical trials utilizing endovascular brachytherapy after coronary angioplasty have shown promising preliminary results. Numerous clinical trials have been initiated to evaluate different delivery systems and source types. In this study, the dose-rate effect is investigated using a biophysical model derived from linear-quadratic formalism. Materials and Methods. The dose-rate effect is quantified using the Dale's formulation, which is based on a linear-quadratic model. This model converts the total absorbed dose into the biological equivalent dose (BED) based on the dose rate, total dose, treatment duration, biological endpoint (α/β ratio), and sublethal damage repair constant. The calculations are performed for two common source configurations used in current clinical trials (192Ir and 90Sr/Y). Results. At smaller radial distance, the dose rate is higher, hence BED increases due to the increase in the relative effectiveness per unit dose (RE) and absorbed dose for a given treatment duration. For 90Sr/Y source, a similar trend is observed; however, it is at a much greater magnitude. The RE for 192Ir is close to unity, which is equivalent to that of external beam irradiation. Conclusion. Although current clinical trials in endovascular brachytherapy report similar absorbed dose, the biological effects may be different due to the extremely high gradient of dose rate near the sources, a variety of isotopes and delivery systems, and different dose prescriptions. If the theoretical predictions in this study are validated in clinical trials, the proposed model can be useful to compare different protocols, design new delivery systems and isotopes, and optimize how radiation is delivered.

Percutaneous transluminal coronary angioplasty (PTCA) was introduced 22 years ago as a nonsurgical catheter-based treatment for obstructive coronary artery disease. Over the following 2 decades, major advances in equipment and techniques led to tremendous growth in the use of PTCA to treat coronary artery disease and angina. Restenosis persists as the limiting factor in the maintenance of vessel patency after PTCA, occurring in 30% to 50% of patients and accounting for significant morbidity and health care expenditures. Plaque persistence and vessel recoil, thrombus formation, constrictive remodeling, and neointimal proliferation are the primary contributors to the development of restenosis after PTCA. Early clinical trials in restenosis prevention using various revascularization devices, antiplatelet drugs, antithrombotic drugs, and antiinflammatory drugs were uniformly negative. Coronary stents are the only devices that have shown a reduction in the incidence of restenosis. Recently, novel therapies, such as intracoronary radiation, antioxidant drugs, and platelet-derived growth factor antagonists, have shown reductions in the incidence of restenosis in small randomized trials. This review focuses on the etiology and pathophysiology of restenosis and discusses current and future therapies that may reduce the incidence of restenosis.

Purpose. In this study, a theoretical assessment of late cardiac complication from endovascular brachytherapy is performed using the integrated logistic model. Materials and Methods. Calculation were performed for various lengths of Ir-192 sources using α / β = 3.2 for the endpoint of chronic ischemia, TD 50/5 = 7,000 cGy, and TD 5/5 = 5,000 cGy. The dose distribution over a standard heart was divided into volume elements with uniform dose (dose-volume histogram). Using linear-quadratic equation, the dose in each of the volume elements was converted into dose equivalent to standard fractionation external beam irradiation. The normal tissue complication probability (NTCP) for each volume element was calculated and combined together to arrive at the cumulative risk of late cardiac complication. The NTCP was plotted against the dose prescribed at 2-mm radial distance for four treatment lengths. Results. (1) The overall risk of late cardiac toxicity (chronic ischemia within 5 years) was estimated to be less than 1% for current clinical trials using Ir-192. (2) There is a volume effect with higher risk for larger irradiated volume, which can come from longer treatment time, the same dose prescribed at a greater radial distance, and a longer source train. (3) The NTCP vs. dose demonstrates a sigmoidal relationship. There is a threshold dose (about 500 cGy), below which the risk is minimal; the gradient of the curve is greater for longer treatment length. Conclusion. If the prediction from this model is validated with clinical data, it will contribute to guidelines for dose prescription, dose escalation, evaluation of new source design, and multivessel treatment.

A coaxial catheter system for containment of distal embolization is described. Utilizing a novel 0.014" hypotube with a distal elastomeric occlusion balloon, the PercuSurge GuardWire functions as a guidewire while trapping distal embolization resulting from more proximal intervention. The particulate debris is evacuated with a single operator exchange aspiration catheter (Export catheter) prior to deflation of the distal occlusion balloon. This animal study confirmed the feasibility of concept. The system was easily delivered through tortuous coronary anatomy. The GuardWire served as an adequate rail for delivery of dilatation balloons and a multitude of stents. There was no evidence of deep wall damage from low-pressure inflation and apposition of the distal occlusion balloon.

The Thrombolysis In Myocardial Infarction (TIMI) flow grade achieved in the infarct-related artery (IRA) during reperfusion therapy for acute myocardial infarction (AMI) is directly related to myocardial salvage. Recently, several series have demonstrated the safety of stenting in AMI and documented a larger postprocedure luminal diameter than that found at angioplasty, although no study has compared the effect of PTCA and stenting in AMI on flow characteristics of the IRA. The residual stenosis and the number of frames required to opacify standardized angiographic landmarks normalized for vessel length (corrected TIMI frame count) or compared with flow in a corresponding normal coronary artery (TIMI frame count index) were determined for the IRA of 39 patients who underwent angioplasty or stenting for AMI. Baseline characteristics were similar for the 20 patients who underwent stenting and the 19 patients who underwent percutaneous transluminal coronary angioplasty. After intervention, the luminal diameter was greater (3.24 vs 2.09 mm, p

The initial adoption of percutaneous coronary intervention (PCI) for unprotected left main coronary artery (LMCA) obstruction was tempered by poor acute outcomes after balloon angioplasty and the potential lethality of restenosis in the left main trunk suggested by bare-metal stent registries.1 The marked antirestenotic efficacy of drug-eluting stents (DES) ushered in a new wave of enthusiasm for unprotected LMCA intervention. However, the accumulation of robust data to guide and support clinical practice has been challenged by the relatively low prevalence of this lesion subset combined with its historical characterization as a “forbidden zone” for PCI. The DES left main database has grown from initial, small, single-center experiences2–4 to larger multicenter registries,5 prospective, risk-adjusted comparisons with coronary artery bypass grafting,6 and most recently to small randomized clinical trials and prespecified subgroups of larger clinical trials.7,8 Catalyzed by an ethos in interventional cardiology that embraces (1) investigation, (2) dissemination of new information through journals, conferences, and a tradition of live-case demonstration; and (3) rapid adaptation of new techniques, there has been a marked evolution and improvement of the technical approach to unprotected LMCA intervention in a remarkably short period of time. The study reported by Palmerini et al9 in this issue of the Circulation Cardiovascular Intervention provides further pressure on interventional cardiologists to follow a straightforward maxim: simpler is usually better. Article see p 185 The interpretation of the studies of left main PCI with DES has been complicated by heterogeneity within study populations related to both the disease location (ostial, shaft, or distal bifurcation) and the technical approach used (single stent, dedicated 2-stent technique, or provisional stenting of the left main with “bail-out” stenting of the branch vessel). The early, single-center observational studies of DES for the unprotected LMCA demonstrated the dependence of clinical outcome …

Background. Recent clinical studies indicate that intravascular brachytherapy (IVB) can reduce the rate of restenosis substantially after angioplasty procedures. However, no clinical guidelines exist for optimal therapy. Methods. The members of the IVB Subcommittee of the American Brachytherapy Society (ABS) identified the areas of consensus and controversies in IVB to issue the ABS perspective on IVB, based on analysis of published reports and the clinical experience of the members in brachytherapy. Results. IVB is still experimental. The long-term efficacy, toxicity, the target tissue, and dose required for IVB are not established. The ABS recommends that IVB procedures must be performed, with careful attention to radiation-related issues, in the context of controlled multidisciplinary clinical trials with the approval of the institutional review board, the Nuclear Regulatory Commission, the Food and Drug Administration, and under an Investigational Device Exemption. The therapeutic radiologist, with a qualified radiation physicist, is responsible for dose prescription and delivery and needs to be present during the IVB procedure as part of this multidisciplinary team. The long-term outcome from these studies should be reviewed critically and published in peer-reviewed journals. The ABS endorsed the dosimetric guidelines of the American Association of Physicists in Medicine Task Group 60 (AAPM TG-60) report. The ABS recommends that dose specification be defined clearly; to allow comparisons between studies, the dose should be prescribed at 2 mm from the source for intracoronary brachytherapy and at an average luminal radius of +2 mm for peripheral vascular brachytherapy. The prescription doses at the above point is generally in the 12–18 Gy range. Comprehensive procedures for quality assurance, radiation protection, and emergencies should be in place before initiating an IVB program. Higher energy beta sources, lower energy gamma sources, dose-volume histograms, and correlation of three-dimensional reconstructions of delivered dose with patterns of failure are areas for further research. Conclusion. The ABS perspective on IVB is presented to assist the interventional team in developing protocols for the use of IVB in the prevention of restenosis. Long-term outcome data with a standardized reporting system are needed to establish the role of brachytherapy in preventing vascular restenosis. Endovascular brachytherapy is a new and evolving modality, and these recommendations are subject to modifications as new data become available.

At our institution, elective coronary interventions are performed without formal surgical backup. Instead, a policy of "standby cardiopulmonary support" (CPS), and "next-available operating room" is used. Standby CPS requires a perfusionist dedicated to the catheterization laboratory with immediate access to CPS apparatus. Between January 1989 and June 1994 we performed 2,850 elective coronary interventions. Eleven patients (0.4%) required emergency CPS. None of these patients fell into a high-risk category for PTCA (i.e., sole circulation, ejection fraction