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Objectives: The primary objective of this study was to determine whether intracoronary administration of the adenoviral gene for fibroblast growth factor (Ad5FGF-4) can improve myocardial perfusion compared with placebo.Background: Animal studies and observational clinical studies have shown improvement in perfusion of the ischemic myocardium using genes encoding angiogenic growth factors; however, randomized, double-blind data in humans are lacking.Methods: We performed a randomized, double-blind, placebo-controlled trial of intracoronary injection of 10(10) adenoviral particles containing a gene encoding fibroblast growth factor (Ad5FGF-4) to determine the effect on myocardial perfusion. Fifty-two patients with stable angina and reversible ischemia comprising >9% of the left ventricle on adenosine single-photon emission computed tomography (SPECT) imaging were randomized to gene therapy (n = 35) or placebo (n = 17). Clinical follow-up was performed, and 51 (98%) patients underwent a second adenosine SPECT scan after 8 weeks.Results: Overall (n = 52), the mean total perfusion defect size at baseline was 32.4% of the left ventricle, with 20% reversible ischemia and 12.5% scar. At eight weeks, Ad5FGF-4 injection resulted in a significant reduction of ischemic defect size (4.2% absolute, 21% relative; p < 0.001) and placebo-treated patients had no improvement (p = 0.32). Although the change in reversible perfusion defect size between Ad5FGF-4 and placebo was not significant (4.2% vs. 1.6%, p = 0.14), when a single outlier was excluded a significant difference was observed (4.2% vs. 0.8%, p < 0.05). Ad5FGF-4 was well tolerated and did not result in any permanent adverse sequelae.Conclusions: Intracoronary injection of Ad5FGF-4 showed an encouraging trend for improved myocardial perfusion; however, further studies of therapeutic angiogenesis with Ad5FGF-4 will be necessary. [ABSTRACT FROM AUTHOR]

Background: The utility of polymer-permanent, polymer-absorbable, and polymer-free drug-eluting stents (DES) in the context of different eluting drugs in patients undergoing percutaneous coronary intervention (PCI) remains controversial., Objectives: The purpose of this study was to compare the efficacy of different DES strategies in post-PCI patients., Methods: Digital databases were searched to select all randomized control trials. Different combinations of DES were directly compared with permanent-polymer sirolimus-eluting stents. The primary outcome was major adverse cardiovascular events; a composite of cardiovascular mortality, myocardial infarction (MI), and target vessel revascularization. A network meta-analysis was performed to determine the net relative risk (RR) and its 95% CI., Results: A total of 314 randomized control trials comprising 345,749 patients with coronary artery disease undergoing PCI were included. Compared with polymer-permanent sirolimus-eluting stent, polymer-free titanium-nitride-oxide (RR: 0.68; 95% CI: 0.53-0.87), polymer-permanent everolimus (RR: 0.89; 95% CI: 0.82-0.96), and zotarolimus stents (RR: 0.89; 95% CI: 0.79-0.99) had a lower risk of major adverse cardiovascular events at 5 years. Polymer-free titanium-nitride-oxide stents also had a significantly lower incidence of stent thrombosis (RR: 0.28; 95% CI: 0.13-0.59) and MI (RR: 0.41; 95% CI: 0.27-0.62) at 1 year. Bare metal stents had a significantly higher 1-year risk of MI (RR: 1.52; 95% CI: 1.25-1.86), and need for target vessel revascularization (RR: 2.26; 95% CI: 1.93-2.64)., Conclusions: In comparison with polymer-permanent sirolimus, the newer stents including polymer-free titanium-nitride-oxide, polymer-permanent everolimus, and zotarolimus stents significantly reduce the risk of long-term ischemic events., Competing Interests: Funding support and author disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Systemic thromboxane A2 generation, assessed by quantifying the concentration of stable thromboxane B2 metabolites (TXB2-M) in the urine adjusted for urinary creatinine, is strongly associated with mortality risk. We sought to define optimal TXB2-M cutpoints for aspirin users and nonusers and determine if adjusting TXB2-M for estimated glomerular filtration rate (eGFR) in addition to urinary creatinine improved mortality risk assessment., Methods: Urinary TXB2-M were measured by competitive ELISA in 1363 aspirin users and 1681 nonusers participating in the Framingham Heart Study. Cutpoints were determined for TXB2-M and TXB2-M/eGFR using log-rank statistics and used to assess mortality risk by Cox proportional hazard modeling and restricted mean survival time. Multivariable models were compared using the Akaike Information Criterion (AIC). A cohort of 105 aspirin users with heart failure was used for external validation., Results: Optimized cutpoints of TXB2-M were 1291 and 5609 pg/mg creatinine and of TXB2-M/eGFR were 16.6 and 62.1 filtered prostanoid units (defined as pg·min/creatinine·mL·1.73 m2), for aspirin users and nonusers, respectively. TXB2-M/eGFR cutpoints provided more robust all-cause mortality risk discrimination than TXB2-M cutpoints, with a larger unadjusted hazard ratio (2.88 vs 2.16, AIC P < 0.0001) and greater differences in restricted mean survival time between exposure groups (1.46 vs 1.10 years), findings that were confirmed in the external validation cohort of aspirin users. TXB2-M/eGFR cutpoints also provided better cardiovascular/stroke mortality risk discrimination than TXB2-M cutpoints (unadjusted hazard ratio 3.31 vs 2.13, AIC P < 0.0001)., Conclusion: Adjustment for eGFR strengthens the association of urinary TXB2-M with long-term mortality risk irrespective of aspirin use., (© Association for Diagnostics & Laboratory Medicine 2024. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Persistent systemic thromboxane generation, predominantly from nonplatelet sources, in aspirin (ASA) users with cardiovascular disease (CVD) is a mortality risk factor., Objectives: This study sought to determine the mortality risk associated with systemic thromboxane generation in an unselected population irrespective of ASA use., Methods: Stable thromboxane B 2 metabolites (TXB 2 -M) were measured by enzyme-linked immunosorbent assay in banked urine from 3,044 participants (mean age 66 ± 9 years, 53.8% women) in the Framingham Heart Study. The association of TXB 2 -M to survival over a median observation period of 11.9 years (IQR: 10.6-12.7 years) was determined by multivariable modeling., Results: In 1,363 (44.8%) participants taking ASA at the index examination, median TXB 2 -M were lower than in ASA nonusers (1,147 pg/mg creatinine vs 4,179 pg/mg creatinine; P < 0.0001). TXB 2 -M were significantly associated with all-cause and cardiovascular mortality irrespective of ASA use (HR: 1.96 and 2.41, respectively; P < 0.0001 for both) for TXB 2 -M in the highest quartile based on ASA use compared with lower quartiles, and remained significant after adjustment for mortality risk factors for similarly aged individuals (HR: 1.49 and 1.82, respectively; P ≤ 0.005 for both). In 2,353 participants without CVD, TXB 2 -M were associated with cardiovascular mortality in ASA nonusers (adjusted HR: 3.04; 95% CI: 1.29-7.16) but not in ASA users, while ASA use was associated with all-cause mortality in those with low (adjusted HR: 1.46; 95% CI: 1.14-1.87) but not elevated TXB 2 -M., Conclusions: Systemic thromboxane generation is an independent risk factor for all-cause and cardiovascular mortality irrespective of ASA use, and its measurement may be useful for therapy modification, particularly in those without CVD., Competing Interests: Funding Support and Author Disclosures This study was supported by a grant from American Heart Association (17GRNT3360007 to Dr Rade). The parent Framingham Heart Study was supported by contracts NO1-HC-25195, HHSN268201500001I, and 75N92019D00031 from the National Heart, Lung, and Blood Institute. Dr Vasan is supported in part by the Evans Medical Foundation and the Jay and Louis Coffman Endowment from the Department of Medicine, Boston University School of Medicine. The authors had sole control of the design of the study, collection, analyses, and dissemination of the data. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Nonplatelet thromboxane generation, stimulated largely by oxidative stress, is a novel mortality risk factor in individuals with coronary artery disease. Though inversely associated with left ventricular ejection fraction (LVEF), a potential role in the pathobiology of heart failure (HF) remains poorly defined. Nonplatelet thromboxane generation and oxidative stress were assessed by measuring urine thromboxane-B 2 metabolites (TXB 2 -M) and 8-isoPGF 2α by ELISA in 105 subjects taking aspirin and undergoing right heart catheterization for evaluation of HF, valve disease, or after transplantation. Multivariable logistic regression and survival analyses were used to define associations of TXB 2 -M to invasive measures of cardiovascular performance and 4-year clinical outcomes. TXB 2 -M was elevated (>1,500 pg/mg creatinine) in 46% of subjects and correlated with HF severity by New York Heart Association (NYHA) functional class and brain natriuretic peptide level, modestly with LVEF, but not with HF etiology. There was no association of oxidative stress to HF type or etiology but a trend with NYHA functional class. Multiple invasive hemodynamic parameters independently associated with TXB 2 -M after adjustment for oxidative stress, age, sex, and race with pulmonary effective arterial elastance ( E a pulmonary ), reflective of right ventricular afterload, being the most robust on hierarchical analysis. Similar to E a pulmonary , elevated urinary TXB 2 -M is associated with increased risk of death (adjusted HR = 2.15, P = 0.037) and a combination of death, transplant, or mechanical support initiation (adjusted HR = 2.0, P = 0.042). Nonplatelet TXA 2 thromboxane generation is independently associated with HF severity reflected by invasive measures of cardiovascular performance, particularly right ventricular afterload, and independently predicted long-term mortality risk. NEW & NOTEWORTHY Nonplatelet thromboxane generation in heart failure is independently associated with risk of death, transplant, or need for mechanical support. Measurement of urine thromboxane metabolites using a clinically available assay may be a useful surrogate for invasive measurement of cardiovascular hemodynamics and performance that could provide prognostic information and facilitate tailoring of therapy in patients with heart failure. Inhibiting thromboxane generation or its biological effects is a potential strategy for improving cardiovascular performance and outcomes in heart failure.

Objective: To evaluate the impact of COVID-19 pandemic migitation measures on of ST-elevation myocardial infarction (STEMI) care., Background: We previously reported a 38% decline in cardiac catheterization activations during the early phase of the COVID-19 pandemic mitigation measures. This study extends our early observations using a larger sample of STEMI programs representative of different US regions with the inclusion of more contemporary data., Methods: Data from 18 hospitals or healthcare systems in the US from January 2019 to April 2020 were collecting including number activations for STEMI, the number of activations leading to angiography and primary percutaneous coronary intervention (PPCI), and average door to balloon (D2B) times. Two periods, January 2019-February 2020 and March-April 2020, were defined to represent periods before (BC) and after (AC) initiation of pandemic mitigation measures, respectively. A generalized estimating equations approach was used to estimate the change in response variables at AC from BC., Results: Compared to BC, the AC period was characterized by a marked reduction in the number of activations for STEMI (29%, 95% CI:18-38, p < .001), number of activations leading to angiography (34%, 95% CI: 12-50, p = .005) and number of activations leading to PPCI (20%, 95% CI: 11-27, p < .001). A decline in STEMI activations drove the reductions in angiography and PPCI volumes. Relative to BC, the D2B times in the AC period increased on average by 20%, 95%CI (-0.2 to 44, p = .05)., Conclusions: The COVID-19 Pandemic has adversely affected many aspects of STEMI care, including timely access to the cardiac catheterization laboratory for PPCI., (© 2020 Wiley Periodicals LLC.)

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Whether very young patients (≤35-year-old) differ in the prevalence, presentation and prognosis of ACS is not well known. Of 43,446 patients who were referred to a tertiary care cardiac catheterization laboratory between January 1, 2006 and June 30, 2017, 26,545 patients were ACS (defined as ST Elevation MI, Non-ST Elevation MI or unstable angina pectoris). Detailed chart review was performed and characteristics at baseline were compared for ages ≤35 years, ages 36 to 54 years and ages ≥55 years. A total of 291 (1.1%) were ≤35-year-old, 7,649 (28.8) were 36 to 54-year-old and 18,605 (70.1%) were ≥55-year-old. ACS patients aged ≤35-year-old, were more likely to be men, Caucasian white, smoker, obese, and have family history of coronary artery disease and less likely to have comorbidities such as hypertension, diabetes mellitus, and hyperlipidemia compared with older patients. They were also more likely to present with elevated troponin levels than other groups. They also tended to present with late ST elevation myocardial infarction and were more likely to receive bare metal stents than older patients. The prevalence of 2- and 3-vessel disease was lower compared with older patients. They also had higher prevalence of cardiogenic shock. Compared with 36 to 54-year-old patients, ≤35-year-old were at significant higher risk of 30-day mortality in a multivariable adjusted regression model (Odds ratio 5.65, 95% confidence interval 2.49 to 12.82, p <0.001). Very young patients comprised ∼1% of all ACS cases but had much more prevalence of modifiable risk factors and significantly worse mortality. Modifying these risk factors may mitigate the risk in these patients and should be studied in the future., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: Arterial thrombosis leading to ischemic injury worsens the prognosis of many patients with cardiovascular disease. PZ-128 is a first-in-class pepducin that reversibly inhibits PAR1 (protease-activated receptor 1) on platelets and other vascular cells by targeting the intracellular surface of the receptor. The TRIP-PCI (Thrombin Receptor Inhibitory Pepducin in Percutaneous Coronary Intervention) trial was conducted to assess the safety and efficacy of PZ-128 in patients undergoing cardiac catheterization with intent to perform percutaneous coronary intervention. Approach and Results: In this randomized, double-blind, placebo-controlled, phase 2 trial, 100 patients were randomly assigned (2:1) to receive PZ-128 (0.3 or 0.5 mg/kg), or placebo in a 2-hour infusion initiated just before the start of cardiac catheterization, on top of standard oral antiplatelet therapy. Rates of the primary end point of bleeding were not different between the combined PZ-128 doses (1.6%, 1/62) and placebo group (0%, 0/35). The secondary end points of major adverse coronary events at 30 and 90 days did not significantly differ but were numerically lower in the PZ-128 groups (0% and 2% in the PZ-128 groups, 6% and 6% with placebo, p=0.13, p=0.29, respectively). In the subgroup of patients with elevated baseline cardiac troponin I, the exploratory end point of 30-day major adverse coronary events + myocardial injury showed 83% events in the placebo group versus 31% events in the combined PZ-128 drug groups, an adjusted relative risk of 0.14 (95% CI, 0.02-0.75); P =0.02., Conclusions: In this first-in-patient experience, PZ-128 added to standard antiplatelet therapy appeared to be safe, well tolerated, and potentially reduced periprocedural myonecrosis, thus providing the basis for further clinical trials. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02561000.

Background: Recent studies suggest that primary percutaneous coronary intervention (PCI) and targeted temperature management (TTM) improve outcome in ST-segment elevation myocardial infarction (STEMI) complicated by out-of-hospital cardiac arrest (OHCA). The objective of this study was to evaluate a contemporary series of patients with STEMI and OHCA to characterize treatment approaches and predictors of neurologic outcome., Methods: From January 2009 through November 2012, a total of 239 patients who underwent emergent coronary angiography at 10 medical centers across the United States were enrolled. All patients suffered OHCA with STEMI on either the prehospital or post-resuscitation electrocardiogram. Neurologic outcome was assessed using the cerebral performance category (CPC) score. Predictors of neurologic outcome were determined using multivariate logistic regression analysis. The primary endpoint was in-hospital survival with good neurologic function (CPC score 1 or 2)., Results: Mean age was 60 ± 13 years, 72% were male, and the majority of patients had a history of cardiovascular event. Initial rhythm was ventricular fibrillation in 72%. At hospital presentation, 76% of patients were intubated, 37% were in cardiogenic shock, and 33% were receiving vasopressors. Primary PCI was performed in 74%, with an average door-to-balloon time of 95 ± 77 minutes, and TTM was used in 51%. Forty-four percent of patients had full neurologic recovery (CPC score 1) and 55% had good neurologic function. Overall in-hospital survival rate was 66%. Independent predictors of in-hospital survival with good neurologic function were: receiving bystander cardiopulmonary resuscitation, location of arrest, receiving drug-eluting stents, and not experiencing a recurrent cardiac arrest., Conclusions: Short-term survival for patients with STEMI and OHCA undergoing emergent coronary angiography and revascularization with TTM in this contemporary, multicenter registry was high and neurologic outcome was good in more than half of patients.

Objective: Protease-activated receptor-1 (PAR1) is classically activated by thrombin and is critical in controlling the balance of hemostasis and thrombosis. More recently, it has been shown that noncanonical activation of PAR1 by matrix metalloprotease-1 (MMP1) contributes to arterial thrombosis. However, the role of PAR1 in long-term development of atherosclerosis is unknown, regardless of the protease agonist., Approach and Results: We found that plasma MMP1 was significantly correlated ( R =0.33; P =0.0015) with coronary atherosclerotic burden as determined by angiography in 91 patients with coronary artery disease and acute coronary syndrome undergoing cardiac catheterization or percutaneous coronary intervention. A cell-penetrating PAR1 pepducin, PZ-128, currently being tested as an antithrombotic agent in the acute setting in the TRIP-PCI study (Thrombin Receptor Inhibitory Pepducin-Percutaneous Coronary Intervention), caused a significant decrease in total atherosclerotic burden by 58% to 70% ( P <0.05) and reduced plaque macrophage content by 54% ( P <0.05) in apolipoprotein E-deficient mice. An MMP1 inhibitor gave similar beneficial effects, in contrast to the thrombin inhibitor bivalirudin that gave no improvement on atherosclerosis end points. Mechanistic studies revealed that inflammatory signaling mediated by MMP1-PAR1 plays a critical role in amplifying tumor necrosis factor α signaling in endothelial cells., Conclusions: These data suggest that targeting the MMP1-PAR1 system may be effective in tamping down chronic inflammatory signaling in plaques and halting the progression of atherosclerosis., (© 2018 American Heart Association, Inc.)

Background: Systemic thromboxane generation, not suppressible by standard aspirin therapy and likely arising from nonplatelet sources, increases the risk of atherothrombosis and death in patients with cardiovascular disease. In the RIGOR (Reduction in Graft Occlusion Rates) study, greater nonplatelet thromboxane generation occurred early compared with late after coronary artery bypass graft surgery, although only the latter correlated with graft failure. We hypothesize that a similar differential association exists between nonplatelet thromboxane generation and long-term clinical outcome., Methods and Results: Five-year outcome data were analyzed for 290 RIGOR subjects taking aspirin with suppressed platelet thromboxane generation. Multivariable modeling was performed to define the relative predictive value of the urine thromboxane metabolite, 11-dehydrothromboxane B 2 (11-dhTXB 2 ), measured 3 days versus 6 months after surgery on the composite end point of death, myocardial infarction, revascularization or stroke, and death alone. 11-dhTXB 2 measured 3 days after surgery did not independently predict outcome, whereas 11-dhTXB 2 >450 pg/mg creatinine measured 6 months after surgery predicted the composite end point (adjusted hazard ratio, 1.79; P =0.02) and death (adjusted hazard ratio, 2.90; P =0.01) at 5 years compared with lower values. Additional modeling revealed 11-dhTXB 2 measured early after surgery associated with several markers of inflammation, in contrast to 11-dhTXB 2 measured 6 months later, which highly associated with oxidative stress., Conclusions: Long-term nonplatelet thromboxane generation after coronary artery bypass graft surgery is a novel risk factor for 5-year adverse outcome, including death. In contrast, nonplatelet thromboxane generation in the early postoperative period appears to be driven predominantly by inflammation and did not independently predict long-term clinical outcome., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Background: Persistent thromboxane (TX) generation while receiving aspirin therapy is associated with an increased risk of cardiovascular events. The Reduction in Graft Occlusion Rates (RIGOR) study found that aspirin-insensitive TXA2 generation, indicated by elevated urine 11-dehydro-TXB2 (UTXB2) 6 months after coronary artery bypass graft surgery, was a potent risk factor for vein graft thrombosis and originated predominantly from nonplatelet sources. Our goal was to identify risks factors for nonplatelet TXA2 generation., Methods and Results: Multivariable modeling was performed by using clinical and laboratory variables obtained from 260 RIGOR subjects with verified aspirin-mediated inhibition of platelet TXA2 generation. The strongest variable associated with UTXB2 6 months after surgery, accounting for 47.2% of the modeled effect, was urine 8-iso-prostaglandin (PG)F2α, an arachidonic acid metabolite generated nonenzymatically by oxidative stress (standardized coefficient 0.442, P<0.001). Age, sex, race, lipid therapy, creatinine, left ventricular ejection fraction, and aspirin dose were also significantly associated with UTXB2 (P<0.03), although they accounted for only 4.8% to 10.2% of the modeled effect. Urine 8-iso-PGF2α correlated with risk of vein graft occlusion (odds ratio 1.67, P=0.001) but was not independent of UTXB2. In vitro studies revealed that endothelial cells generate TXA2 in response to oxidative stress and direct exposure to 8-iso-PGF2α., Conclusions: Oxidative stress-induced formation of 8-iso-PGF2α is strongly associated with nonplatelet thromboxane formation and early vein graft thrombosis after coronary artery bypass graft surgery. The endothelium is potentially an important source of oxidative stress-induced thromboxane generation. These findings suggest therapies that reduce oxidative stress could be useful in reducing cardiovascular risks associated with aspirin-insensitive thromboxane generation., (© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Optimal medical therapy unarguably forms the cornerstone of management for patients with stable coronary artery disease. There is, however, a significant body of evidence suggesting that reduction of ischemia can be achieved more effectively with revascularization than medical therapy and can confer significant symptomatic and prognostic advantages. Nonetheless, owing to limitations of coronary angiography and conventional non-invasive functional testing for myocardial ischemia, targeting of hemodynamically significant coronary stenoses for revascularization is often difficult. We discuss the role of invasive fractional-flow reserve evaluation in guiding percutaneous revascularization procedures for patients with stable coronary artery disease and its potential impact on outcomes for these patients.

Background: Transradial (TR) access for primary percutaneous coronary intervention (PCI) is becoming accepted as the preferred approach but has not gained widespread adoption due to technical challenges that may limit procedural success and delay time to revascularization, particularly among patients treated by inexperienced operators. We report our experience over the first 2 years of our TR primary PCI program and determined the impact of TR access on clinical and procedural outcomes., Methods: Clinical characteristics and procedural outcomes were collected prospectively from 488 patients presenting with ST-segment elevation myocardial infarction and compared according to whether patients underwent primary PCI via the TR or transfemoral (TF) approach., Results: Hospital mortality was very low in both groups (1.1% [TR] vs 2.6% [TF]; P=.23). Access-site intended procedural success for primary PCI was equivalent (98.4% for TR vs 98.6% for TF; P=.85). Catheterization room-to-balloon (RTB) times were significantly lower among patients undergoing TR primary PCI as compared with those in the TF group (20:33 ± 06:41 [TR] vs 25:11 ± 08:22 [TF]; P<.001). TR patients treated by operators who had performed >50 TR PCIs had lower RTB times (20:03 ± 06:12 vs 24:26 ± 10:01; P<.06) and lower doses of radiation exposure (1812 ± 1007 mGy vs 2827 ± 954 mGy; P<.01) than patients treated by less experienced operators. Dual-purpose guide catheter usage was also associated with lower RTB times (18:38 ± 5:42 vs 25:15 ± 8:20; P<.001) and radiation exposure (1824 ± 6205 mGy vs 2407 ± 1389 mGy; P<.01)., Conclusions: TR primary PCI may be performed rapidly and successfully despite only modest operator and institutional experience.

Background: The VerifyNow P2Y12 assay assesses the adequacy of clopidogrel therapy by measuring ADP-induced platelet activation in whole blood. Low hematocrit is associated with high clopidogrel on-treatment platelet reactivity (HTPR) defined by this assay., Objectives: To characterize the effect of hematocrit on VerifyNow values and determine if it is due to hematocrit-dependent changes in intrinsic platelet reactivity or an in vitro assay phenomenon., Patients/methods: Adenosine diphosphate-induced platelet activation was measured using the VerifyNow P2Y12 assay, whole blood impedance and light transmission platelet aggregometry (LTA) before and after clopidogrel loading in 113 patients undergoing elective cardiac catheterization. Iso-TRAP-induced platelet activation was additionally measured using the VerifyNow device. Multivariate modeling employing clinical and laboratory variables was used to investigate the association between hematocrit and VerifyNow values., Results: VerifyNow P2Y12 reaction units (PRU) and iso-TRAP Base units before and after clopidogrel loading, but not their relative change, exhibited strong negative correlation with hematocrit (P ≤ 0.0005 for both). While hematocrit remained a strong predictor of post-clopidogrel PRU (P = 0.001) in multivariate modeling, it was independent of post-clopidogrel ADP-induced platelet reactivity as measured by LTA (P = 0.001). Correcting for the effects of hematocrit resulted in a 15-39% reduction in the prevalence of HTPR defined by thresholds of 208-236 PRU., Conclusions: The effect of hematocrit on VerifyNow PRU values is an in vitro phenomenon that is independent of intrinsic change in ADP-induced platelet reactivity and clopidogrel responsiveness. Correcting for hematocrit when using this assay may more accurately identify patients with HTPR that may benefit from alternative antiplatelet therapy., (© 2013 International Society on Thrombosis and Haemostasis.)

Thromboxane and its receptor have emerged as key players in modulating vascular thrombotic events. Thus, a dysfunctional hTP genetic variant may protect against (hypoactivity) or promote (hyperactivity) vascular events, based upon its activity on platelets. After extensive in silico analysis, six hTP-α variants were selected (C(68)S, V(80)E, E(94)V, A(160)T, V(176)E, and V(217)I) for detailed biochemical studies based on structural proximity to key regions involved in receptor function and in silico predictions. Variant biochemical profiles ranged from severe instability (C(68)S) to normal (V(217)I), with most variants demonstrating functional alteration in binding, expression or activation (V(80)E, E(94)V, A(160)T, and V(176)E). In the absence of patient platelet samples, we developed and validated a novel megakaryocyte based system to evaluate human platelet function in the presence of detected dysfunctional genetic variants. Interestingly, variant V80E exhibited reduced platelet activation whereas A160T demonstrated platelet hyperactivity. This report provides the most comprehensive in silico, in vitro and "in platelet" evaluation of hTP variants to date and highlightscurrent inherent problems in evaluating genetic variants, with possible solutions. The study additionally provides clinical relevance to characterized dysfunctional hTP variants.

Background: Aspirin's therapeutic action is via inhibition of platelet cyclooxygenase 1 (COX-1) thromboxane A2 (TxA2) production. The aim of this study was to evaluate TxA2 production, in the absence of platelet COX-1 activity, in coronary atherosclerotic heart disease patients with and without atherothrombotic myocardial infarction (MI)., Methods and Results: TxA2 production, in the absence of platelet COX-1 activity, was evaluated in 44 patients taking aspirin on 3 commercially available assays that detect metabolites of TxA2 in the urine. Two assays measure urine 11-dehydro-thromboxane B2 (TxB2) alone and 1 measures urine 11-dehydro-TxB2 plus 11-dehydro-2,3-dinor-TxB2. Platelet COX-1 inhibition was confirmed on <10% platelet aggregation in response to ≥1 mmol/L arachidonic acid. Median urine 11-dehydro-TxB2 was no different in those with and without a diagnosis of atherothrombotic MI (325 vs. 311 pg/mg creatinine, P=0.59 via polyclonal ELISA) and (312 vs. 244 pg/mg creatinine, P=0.11 via LC-MS/MS). Median urine 11-dehydro-TxB2 plus 11-dehydro-2,3-dinor-TxB2, however, was higher in those with vs. those without a diagnosis of atherothrombotic MI (1,035 vs. 606 pg/mg creatinine, P=0.03 via monoclonal ELISA)., Conclusions: Differences in TxA2 production, in the absence of platelet COX-1 activity, between those with vs. without atherothrombotic MI were not observed when TxA2 generation was assessed on 11-dehydro-TxB2 production alone (polyclonal ELISA or LC-MS/MS), but differences were observed when TxA2 generation was assessed using 11-dehydro-TxB2 plus 11-dehydro-2,3-dinor-TxB2 (monoclonal ELISA). These findings highlight important differences between different commercially available assays for TxA2 generation and suggest that 11-dehydro-2,3-dinor-TxB2 may be critical to the biology of atherothrombosis.

Background: Elevated urine 11-dehydro TXB(2), an indicator of persistent thromboxane generation in aspirin-treated patients, correlates with adverse cardiovascular outcome and has recently been identified as an independent risk factor for vein graft thrombosis after cardiac bypass surgery in the Reduction in Graft Occlusion Rates (RIGOR) study. The polyclonal antibody-based ELISA used to measure 11-dehydro TXB(2) in these previous studies is no longer clinically available and has been supplanted by a Food and Drug Administration (FDA)-cleared second-generation monoclonal antibody-based ELISA., Objectives: To compare the laboratory and clinical performance of the first- and second-generation assays in a well-defined study population., Methods: 11-dehydro TXB(2) was quantified in 451 urine samples from 229 Reduction in Graft Occlusion Rates (RIGOR) subjects using both ELISA. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and spiking studies were used to investigate discordant assay results. The association of 11-dehydro TXB(2) to clinical outcome was assessed for each assay using multivariate modeling., Results: Median 11-dehydro TXB(2) levels were higher by monoclonal antibody- compared with polyclonal antibody-based ELISA (856 vs. 399 pg mg(-1) creatinine, P < 0.000001), with the latter providing values similar to UPLC-MS/MS. This discrepancy was predominantly as a result of cross-reactivity of the monoclonal antibody with 11-dehydro-2,3-dinor TXB(2), a thromboxane metabolite present in a similar concentration but with a poor direct correlation with 11-dehydro TXB(2). In contrast to the first-generation ELISA, 11-dehydro TXB(2) measured by the monoclonal antibody-based ELISA failed to associate with the risk of vein graft occlusion., Conclusion: Quantification of urine 11-dehydro TXB(2) by monoclonal antibody-based ELISA was confounded by interference from 11-dehydro-2,3-dinor TXB(2) which reduced the accuracy and clinical utility of this second-generation assay., (© 2012 International Society on Thrombosis and Haemostasis.)

Aim: The aim of the present study was to investigate the relative importance of a wide array of patient demographic, procedural, anatomic and perioperative variables as potential risk factors for early saphenous vein graft (SVG) thrombosis after coronary artery bypass graft (CABG) surgery., Methods: The patency of 611 SVGs in 291 patients operated on at four different hospitals enrolled in the Reduction in Graft Occlusion Rates (RIGOR) study was assessed six months after CABG surgery by multidetector computed tomography coronary angiography or clinically-indicated coronary angiography. The odds of graft occlusion versus patency were analyzed using multilevel multivariate logistic regression with clustering on patient., Results: SVG failure within six months of CABG surgery was predominantly an all-or-none phenomenon with 126 (20.1%) SVGs totally occluded, 485 (77.3%) widely patent and only 16 (2.5%) containing high-grade stenoses. Target vessel diameter ≤ 1.5 mm (adjusted OR 2.37, P=0.003) and female gender (adjusted OR 2.46, P=0.01) were strongly associated with early SVG occlusion. In a subgroup analysis of 354 SVGs in which intraoperative graft blood flow was measured, lower mean flow was also significantly associated with SVG occlusion when analyzed as a continuous variable (adjusted OR 0.984, P=0.006) though not when analyzed dichotomously, <40 mL/min versus ≥ 40 mL/min (adjusted OR 1.86, P=0.08)., Conclusion: Small target vessel diameter, female gender and low mean graft blood flow are significant risk factors for SVG thrombosis within six months of CABG surgery in patients on postoperative aspirin therapy. This information may be useful in guiding revascularization strategies in selected patients.

Background: Thrombosis is a major cause of the early failure of vein grafts (VGs) implanted during peripheral and coronary arterial bypass surgeries. Endothelial expression of thrombomodulin (TM), a key constituent of the protein C anticoagulant pathway, is markedly suppressed in VGs after implantation and contributes to local thrombus formation. While stretch-induced paracrine release of transforming growth factor-β (TGF-β) is known to negatively regulate TM expression in heart tissue, its role in regulating TM expression in VGs remains unknown., Methods: Changes in relative mRNA expression of major TGF-β isoforms were measured by quantitative polymerase chain reaction (qPCR) in cultured human saphenous vein smooth muscle cells (HSVSMCs) subjected to cyclic stretch. To determine the effects of paracrine release of TGF-β on endothelial TM mRNA expression, human saphenous vein endothelial cells (HSVECs) were co-cultured with stretched HSVSMCs in the presence of 1D11, a pan-neutralizing TGF-β antibody, or 13C4, an isotype-control antibody. Groups of rabbits were then administered 1D11 or 13C4 and underwent interpositional grafting of jugular vein segments into the carotid circulation. The effect of TGF-β inhibition on TM gene expression was measured by qPCR; protein C activating capacity and local thrombus formation were measured by in situ chromogenic substrate assays; and VG remodeling was assessed by digital morphometry., Results: Cyclic stretch induced TGF-β(1) expression in HSVSMCs by 1.9 ± 0.2-fold (P < .001) without significant change in the expressions of TGF-β(2) and TGF-β(3). Paracrine release of TGF-β(1) by stretched HSVSMCs inhibited TM expression in stationary HSVECs placed in co-culture by 57 ± 12% (P = .03), an effect that was abolished in the presence of 1D11. Similarly, TGF-β(1) was the predominant isoform induced in rabbit VGs 7 days after implantation (3.5 ± 0.4-fold induction; P < .001). TGF-β(1) protein expression localized predominantly to the developing neointima and coincided with marked suppression of endothelial TM expression (16% ± 2% of vein controls; P < .03), a reduction in situ activated protein C (APC)-generating capacity (53% ± 9% of vein controls; P = .001) and increased local thrombus formation (3.7 ± 0.8-fold increase over vein controls; P < .01). External stenting of VGs to limit vessel distension significantly reduced TGF-β(1) induction and TM downregulation. Systemic administration of 1D11 also effectively prevented TM downregulation, preserved APC-generating capacity, and reduced local thrombus in rabbit VGs without observable effect on neointima formation and other morphometric parameters 6 weeks after implantation., Conclusion: TM downregulation in VGs is mediated by paracrine release of TGF-β(1) caused by pressure-induced vessel stretch. Systemic administration of an anti-TGF-β antibody effectively prevented TM downregulation and preserved local thromboresistance without negative effect on VG remodeling., (Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Gefitinib is an epidermal growth factor tyrosine kinase inhibitor used as a targeted chemotherapeutic agent in the treatment of lung cancer and other solid malignancies. Unlike other tyrosine kinase inhibitors, gefitinib is not recognized as having significant cardiotoxicity though it has been reported to be capable of potentiating ADP-induced activation and thromboxane A(2) generation in platelets which could promote thrombosis. We report a case of recurrent myocardial infarction with angiographically documented vulnerable plaque rupture in a patient receiving chronic gefitinib therapy for metastatic carcinoid tumor. Platelet function studies revealed marked ADP-induced platelet activation that was only suppressed by high-dose clopidogrel. Measurement of urine 11-dehydro-thromboxane B(2) also indicated persistent thromboxane A(2) generation despite aspirin therapy, an emerging risk factor for adverse cardiovascular events.

This report describes a case of an acute anterior myocardial infarction secondary to subacute stent thrombosis of a drug-eluting stent within the proximal segment of the left anterior descending artery (LAD) 5 days after percutaneous transluminal coronary angioplasty and stenting (PCI). The patient was initially managed with conventional dual-antiplatelet therapy (aspirin and clopidogrel) and was subsequently found to have complete absence of adenosine diphosphate (ADP) receptor P2Y12 receptor inhibition. Following additional PCI of the LAD and substitution of clopidogrel for the thienopyridine prasugrel, therapeutic platelet inhibition was achieved without recurrence of stent thrombosis.

Patients with acute coronary syndromes who require emergency cardiac surgery present complex management challenges. The early administration of antiplatelet and antithrombotic drugs has improved overall survival for patients with acute myocardial infarction, but to achieve maximal benefit, these drugs are given before coronary anatomy is known and before the decision to perform percutaneous coronary interventions or surgical revascularization has been made. A major bleeding event secondary to these drugs is associated with a high rate of death in medically treated patients with acute coronary syndrome possibly because of subsequent withholding of antiplatelet and antithrombotic therapies that otherwise reduce the rate of death, stroke, or recurrent myocardial infarction. Whether the added risk of bleeding and blood transfusion in cardiac surgical patients receiving such potent antiplatelet or antithrombotic therapy before surgery specifically for acute coronary syndromes affects long-term mortality has not been clearly established. For patients who do proceed to surgery, strategies to minimize bleeding include stopping the anticoagulation therapy and considering platelet and/or coagulation factor transfusion and possibly recombinant-activated factor VIIa administration for refractory bleeding. Mechanical hemodynamic support has emerged as an important option for patients with acute coronary syndromes in cardiogenic shock. For these patients, perioperative considerations include maintaining appropriate anticoagulation, ensuring suitable device flow, and periodically verifying correct device placement. Data supporting the use of these devices are derived from small trials that did not address long-term postoperative outcomes. Future directions of research will seek to optimize the balance between reducing myocardial ischemic risk with antiplatelet and antithrombotics versus the higher rate perioperative bleeding by better risk stratifying surgical candidates and by assessing the effectiveness of newer reversible drugs. The effects of mechanical hemodynamic support on long-term patient outcomes need more stringent analysis.

Objectives: The purpose of this study was to determine if an incomplete response to or inadequate antiplatelet effect of aspirin, or both, contribute to saphenous vein graft (SVG) occlusion after coronary artery bypass graft (CABG) surgery., Background: Thrombosis is the predominant cause of early SVG occlusion. Aspirin, which inhibits cyclooxygenase-1 activity and thromboxane generation in platelets, reduces early SVG occlusion by one-half., Methods: Aspirin responsiveness and platelet reactivity were characterized 3 days and 6 months after coronary artery bypass graft surgery in 229 subjects receiving aspirin monotherapy by platelet aggregation to arachidonic acid, adenosine diphosphate, collagen and epinephrine, Platelet Function Analyzer-100 (Siemens Healthcare Diagnostics, Newark, Delaware) closure time (CT) using collagen/epinephrine agonist cartridge and collagen/adenosine diphosphate (CADP) agonist cartridge, VerifyNow Aspirin assay (Accumetrics, Inc., San Diego, California), and urine levels of 11-dehydro-thromboxane B(2) (UTXB(2)). SVG patency was determined 6 months after surgery by computed tomography coronary angiography., Results: Inhibited arachidonic acid-induced platelet aggregation, indicative of aspirin-mediated cyclooxygenase-1 suppression, occurred in 95% and >99% of subjects 3 days and 6 months after surgery, respectively. Despite this, 73% and 31% of subjects at these times had elevated UTXB(2). Among tested parameters, only UTXB(2) and CADP CT measured 6 months after surgery correlated with outcome. By multivariate analysis, CADP CT of ≤88 s (odds ratio: 2.85, p = 0.006), target vessel diameter of ≤1.5 mm (odds ratio: 2.38, p = 0.01), and UTXB(2) of ≥450 pg/mg creatinine (odds ratio: 2.59, p = 0.015) correlated with SVG occlusion. CADP CT and UTXB(2) in combination further identified subjects at particularly high and low risk for SVG occlusion., Conclusions: Aspirin-insensitive thromboxane generation measured by UTXB(2) and shear-dependent platelet hyper-reactivity measured by Platelet Function Analyzer-100 CADP CT are novel independent risk factors for early SVG thrombosis after coronary artery bypass graft surgery., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Patients with diabetes mellitus have an increased prevalence of vascular disease. Pathologic thrombosis associated with atherosclerotic plaque rupture is a major cause of morbidity and mortality. Platelets are intimately involved in the initiation and propagation of thrombosis. Evidence suggests that platelets from patients with type 2 diabetes have increased reactivity and baseline activation compared to healthy controls. We review the pathophysiology of platelet hyperreactivity in DM patients and its implications in clinical practice, with particular focus on acute coronary syndromes, percutaneous coronary intervention, and novel antiplatelet agents.

Vascular endothelial cells respond to biomechanical forces, such as cyclic stretch and shear stress, by altering gene expression. Since endothelial-derived prostanoids, such as prostacyclin and thromboxane A(2), are key mediators of endothelial function, we investigated the effects of cyclic stretch on the expression of genes in human umbilical vein endothelial cells controlling prostanoid synthesis: cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), prostacyclin synthase (PGIS) and thromboxane A(2) synthase (TXAS). COX-2 and TXAS mRNAs were upregulated by cyclic stretch for 24h. In contrast, PGIS mRNA was decreased and stretch had no effect on COX-1 mRNA expression. We further show that stretch-induced upregulation of COX-2 is mediated by activation of the NF-kappabeta signaling pathway.

Objective: Impairment of the thrombomodulin-protein C anticoagulant pathway has been implicated in pathological thrombosis associated with malignancy. Patients who receive proteasome inhibitors as part of their chemotherapeutic regimen appear to be at decreased risk for thromboembolic events. We investigated the effects of proteasome inhibitors on endothelial thrombomodulin expression and function., Methods and Results: Proteasome inhibitors as a class markedly induced the expression of thrombomodulin and enhanced the protein C activating capacity of endothelial cells. Thrombomodulin upregulation was independent of NF-kappaB signaling, a principal target of proteasome inhibitors, but was instead a direct consequence of increased expression of the Krüppel-like transcription factors, KLF2 and KLF4. These effects were confirmed in vivo, where systemic administration of a proteasome inhibitor enhanced thrombomodulin expression that was paralleled by changes in the expression of KLF2 and KLF4., Conclusions: These findings identify a novel mechanism of action of proteasome inhibitors that may help to explain their clinically observed thromboprotective effects.

Background: Antibodies to complexes of heparin and platelet factor 4 (PF4) are capable of causing heparin-induced thrombocytopenia (HIT). Recent evidence suggests that anti-PF4/heparin antibodies may be prothrombogenic even in the absence of thrombocytopenia and clinically-recognized HIT., Objectives: To determine if induction of anti-PF4/heparin antibodies is an independent risk factor for early saphenous vein graft (SVG) occlusion or adverse clinical outcome after coronary artery bypass graft (CABG) surgery., Patients/methods: Anti-PF4/heparin antibody titers were measured in 368 patients prior to and then 4 days, 6 weeks and 6 months after CABG surgery. Serotonin release assay (SRA) and antibody isotype analysis were also performed on 6-week samples. SVG patency was determined in 297 patients 6 months after surgery by multidetector computed tomography coronary angiography., Results: Six weeks after surgery, 52% of patients were anti-PF4/heparin seropositive and 9% were SRA positive. Six months after surgery, neither the percentage of occluded SVG (19% vs. 20%, P = NS), the percentage of patients with an occluded SVG (33% vs. 33%, P = NS) nor the incidence of adverse clinical events (21% vs. 24%, P = NS) differed between seropositive and seronegative groups. Neither IgG isotype nor SRA positivity was additionally predictive of SVG occlusion or adverse clinical outcome., Conclusion: Induction of anti-PF4/heparin antibodies, even those capable of heparin-dependent platelet activation, is not independently associated with early SVG occlusion or adverse clinical outcomes after CABG surgery.

Therapeutic myocardial angiogenesis and arteriogenesis represent a novel treatment strategy for patients with angina refractory to traditional medical and surgical therapies. The fibroblast growth factors are a family of proteins that are known mediators of angio-/arteriogenesis. Based on promising preclinical animal data, a series of four randomized placebo-controlled clinical trials have been conducted to determine the safety and efficacy of local delivery of fibroblast growth factor 4 with the use of adenovirus-vector-mediated gene transfer to induce myocardial angio-/arteriogenesis in patients with stable angina. This review describes the scientific rationale underlying these clinical trials, provides an overview of their results, and discusses the implications for future studies.

Inflammation and thrombosis are increasingly recognized as interrelated biologic processes. Endothelial cell expression of thrombomodulin (TM), a key component of the anticoagulant protein C pathway, is potently inhibited by inflammatory cytokines. Because the mechanism underlying this effect is largely unknown, we investigated a potential role for the inflammatory transcription factor nuclear factor-kappa B (NF-kappaB). Blocking NF-kappaB activation effectively prevented cytokine-induced down-regulation of TM, both in vitro and in a mouse model of tumor necrosis factor-alpha (TNF-alpha)-mediated lung injury. Although the TM promoter lacks a classic NF-kappaB consensus site, it does contain tandem Ets transcription factor binding sites previously shown to be important for both constitutive TM gene expression and cytokine-induced repression. Using electrophoretic mobility shift assay and chromatin immunoprecipitation, we found that multiple Ets species bind to the TNF-alpha response element within the TM promoter. Although cytokine exposure did not alter Ets factor binding, it did reduce binding of p300, a coactivator required by Ets for full transcriptional activity. Overexpression of p300 also prevented TM repression by cytokines. We conclude that NF-kappaB is a critical mediator of TM repression by cytokines. Further evidence suggests a mechanism involving competition by NF-kappaB for limited pools of the transcriptional coactivator p300 necessary for TM gene expression.

The incidence of antiplatelet factor-4/heparin antibody formation in patients who receive contemporary doses of unfractionated heparin in the setting of percutaneous coronary revascularization is unknown. Also unknown is the ability of these antibodies to activate platelets or adversely affect clinical outcome in the absence of clinically recognized heparin-induced thrombocytopenia. To address these questions, we serially measured antiplatelet factor-4/heparin antibody levels and performed serotonin release assays in patients who underwent percutaneous coronary intervention. Correlations were then made across antibody induction, heparin exposure, and clinical outcome at 6 months.

Background: The need for new treatment strategies for cardiac arrhythmias has motivated our continuing development of gene therapeutic options. Previously, we reported a decreased heart rate in an acute model of atrial fibrillation after atrioventricular nodal gene transfer. Here, we expand those observations to persistent atrial fibrillation and severe heart failure., Methods and Results: After 3 weeks of atrial fibrillation, domestic swine received atrioventricular nodal gene transfer with adenoviruses encoding beta-galactosidase (beta-gal), wild-type Galpha(i2) (wtGi), or constitutively active mutant (cGi). Heart rates in awake, alert animals were not altered by beta-gal or wtGi. cGi caused a sustained 15% to 25% decrease in heart rate. The wtGi effect became evident with sedation. A tachycardia-induced cardiomyopathy was present before gene transfer. In the beta-gal group, cardiomyopathy worsened over time. In the wtGi group, the condition improved slightly, and in the cGi group, ejection fraction was near normal at the end of the study. TUNEL staining results corroborated this finding., Conclusions: cGi overexpression in the porcine atrioventricular node causes physiologically relevant heart rate control in persistent atrial fibrillation. These data advance the development of gene therapy as a potential treatment for common cardiac arrhythmias.

Thrombomodulin (TM), a component of the protein C anticoagulant pathway, is critical for the maintenance of vascular thromboresistance. To facilitate the study of in vivo TM regulation, we cloned and sequenced the cDNA encoding full-length rabbit TM. Translation of the open reading frame predicts a 580 amino acid protein that contains a 19 amino acid signal peptide, one lectin-like and six EGF-like extracellular domains, a 23 amino acid transmembrane domain and a 36 amino acid cytoplasmic domain. In addition, there are three potential N-linked and six O-linked glycosylation sites. Comparison of the predicted rabbit TM protein with those of human, mouse and rat reveals 67-72% primary sequence conservation with identical domain homology. TM gene expression was quantified in rabbit cardiovascular tissue by real-time PCR using primers and probe based on the derived cDNA sequence and found to correlate with protein expression as determined by Western blot analysis.

Nitric oxide (NO) is an antiviral effector of the innate immune system, but few of the viral targets of NO have been identified. We now show that NO inhibits adenovirus replication by targeting the adenovirus proteinase (AVP). NO generated from diethylamine NONOate (DEA-NONOate) or spermine NONOate (Sp-NONOate) inhibited the AVP. Inhibition was reversible with dithiothreitol. The equilibrium dissociation constant for reversible binding to the AVP by Sp-NONOate, or Ki, was 0.47 mM, and the first-order rate constant for irreversible inhibition of the AVP by Sp-NONOate, or ki, was 0.0036 s(-1). Two hallmarks of a successful adenovirus infection were abolished by the NO donors: the appearance of E1A protein and the cleavage of cytokeratin 18 by AVP. Treatment of infectious virus by DEA-NONOate dramatically decreased viral infectivity. These data suggest that NO may be a useful antiviral agent against viruses encoding a cysteine proteinase and in particular may be an antiadenovirus agent.

Thrombomodulin (TM), a key component of the anticoagulant protein C pathway, is a major contributor to vascular thromboresistance. We previously found that TM protein expression is dramatically reduced in autologous vein grafts during the first two weeks after implantation, coincident to a local inflammatory response, and remains suppressed for at least 6 weeks. To determine the proximate cause of TM loss, in vivo gene expression was quantified by real-time PCR. TM gene expression in vein grafts declined >85% during the first postoperative week and remained suppressed >55% at 6 weeks, accounting for the observed changes in protein expression. The effects of vein graft inflammation were evaluated in animals rendered leukopenic with vinblastine before graft implantation. Abrogating the local inflammatory response affected neither TM protein nor gene expression. To determine how hemodynamic forces might modulate TM expression, the surgical protocol was modified to alter blood flow and pressure-induced vessel distension. TM protein and gene expression did not correlate to changes in shear stress but highly correlated to changes in wall tension, both acutely and over time. We conclude that the primary stimulus for altered TM expression in vein grafts is the exposure to arterial pressure. Furthermore, these data identify strain as a novel and important pathway for in vivo TM gene regulation.

Background: The angiogenic response to myocardial ischemia can be augmented in animal models by gene transfer with the use of a replication defective adenovirus (Ad) containing a human fibroblast growth factor (FGF) gene., Methods and Results: The objectives of the Angiogenic GENe Therapy (AGENT) trial were to evaluate the safety and anti-ischemic effects of 5 ascending doses of Ad5-FGF4 in patients with angina and to select potentially safe and effective doses for subsequent study. Seventy-nine patients with chronic stable angina Canadian Cardiovascular Society class 2 or 3 underwent double-blind randomization (1:3) to placebo (n=19) or Ad5-FGF4 (n=60). Safety evaluations were performed at each visit and exercise treadmill testing (ETT) at baseline and at 4 and 12 weeks. Single intracoronary administration of Ad5-FGF4 seemed to be safe and well tolerated with no immediate adverse events. Fever of <1-day duration occurred in 3 patients in the highest-dose group. Transient, asymptomatic elevations in liver enzymes occurred in 2 patients in lower-dose groups. Serious adverse events during follow-up (mean, 311 days) were not different between placebo and Ad5-FGF4. Overall, patients who received Ad5-FGF4 tended to have greater improvements in exercise time at 4 weeks (1.3 versus 0.7 minutes, P=NS, n=79). A protocol-specified, subgroup analysis showed the greatest improvement in patients with baseline ETT < or =10 minutes (1.6 versus 0.6 minutes, P=0.01, n=50)., Conclusions: Results show evidence of favorable anti-ischemic effects with Ad5-FGF4 compared with placebo, and it appears to be safe. Angiogenic gene transfer with Ad5-FGF4 shows promise as a new therapeutic approach to the treatment of angina pectoris.