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Using a prospectively collected database of patients undergoing cardiac catheterization, we sought to compare the outcomes of procedures performed by supervised physician assistants (PAs) with those performed by supervised cardiology fellows-in-training. Outcome measures included procedural length, fluoroscopy use, volume of contrast media, and complications including myocardial infarction, stroke, arrhythmia requiring defibrillation or pacemaker placement, pulmonary edema requiring intubation, and vascular complications. Class 3 and 4 congestive heart failure was more common in patients who underwent procedures by fellows compared with those undergoing procedures by PAs (P = 0.001). PA cases tended to be slightly faster (P = 0.05) with less fluoroscopic time (P < 0.001). The incidence of major complications within 24 hr of the procedure was similar between the two groups (0.54% in PA cases and 0.58% in fellow cases). Under the supervision of experienced attending cardiologists, trained PAs can perform diagnostic cardiac catheterization, including coronary angiography, with complication rates similar to those of cardiology fellows-in-training., (Copyright 2003 Wiley-Liss, Inc.)

Background: Endothelin is a potent vasoconstrictor that has been implicated in the pathogenesis of radiocontrast nephrotoxicity. Endothelin antagonists may reduce the renal hemodynamic abnormalities following radiocontrast administration., Methods: One hundred fifty-eight patients with chronic renal insufficiency [mean serum creatinine +/- SD = 2.7 +/- 1.0 mg/dL (242. 3 to +/- 92.8 micromol/L)] and undergoing cardiac angiography were randomized to receive either a mixed endothelin A and B receptor antagonist, SB 290670, or placebo. All patients received intravenous hydration with 0.45% saline before and after radiocontrast administration. Serum creatinine concentrations were measured at baseline, 24 hours, 48 hours, and 3 to 5 days after radiocontrast administration. The primary end point was the mean change in serum creatinine concentration from baseline at 48 hours; the secondary end point was the incidence of radiocontrast nephrotoxicity, defined as an increase in serum creatinine of > or =0.5 mg/dL (44 micromol/L) or > or = 25% from baseline within 48 hours of radiocontrast administration., Results: The mean increase in serum creatinine 48 hours after angiography was higher in the SB 209670 group [0.7 +/- 0. 7 mg/dL (63.5 +/- 58.6 micromol/L)] than in the placebo group [0.4 +/- 0.6 mg/dL (33.6 +/- 55.1 micromol/L), P = 0.002]. The incidence of radiocontrast nephrotoxicity was also higher in the SB 209670 group (56%) compared with placebo (29%, P = 0.002). This negative effect of SB 209670 was apparent in both diabetic and nondiabetic patients. Adverse effects, especially hypotension or decreased blood pressure, were more common in the SB 209670 group., Conclusions: In patients with chronic renal insufficiency who were undergoing cardiac angiography, endothelin receptor antagonism with SB 209670 and intravenous hydration exacerbate radiocontrast nephrotoxicity compared with hydration alone.

Objectives: This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features. Background Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography., Methods: At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined., Results: Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80%P=0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, P<0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1., Conclusions: With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1., (Copyright 2000 The European Society of Cardiology.)

Objectives: This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features., Background: Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography., Methods: At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined., Results: Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80% p = 0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, p < 0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1., Conclusions: With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1.

Background: Evidence from numerous studies of coronary angiography show differences between observers' assessments of 15% to 45%. The implication of this variation is serious: If readings are erroneous, some patients will undergo revascularization procedures unnecessarily and others will be denied an essential treatment. We evaluated the variation in interpretation of angiograms and its potential effect on appropriateness of use of revascularization procedures., Methods and Results: Angiograms of 308 randomly selected patients previously studied for appropriateness of angiography, coronary artery bypass grafting (CABG), and percutaneous transluminal coronary angioplasty (PTCA) were interpreted by a blinded panel of 3 experienced angiographers and compared with the original interpretations. The potential effect on differences on the appropriateness of revascularization was assessed by use of the RAND criteria. Technical deficiencies were found in 52% of cases. Panel readings tended to show less significant disease (none in 16% of vessels previously read as showing significant disease), less severity of stenosis (43% lower, 6% higher), and lower extent of disease (23% less, 6% more). The classification of CABG changed from necessary/appropriate to uncertain/inappropriate for 17% to 33% of cases when individual ratings were replaced by panel readings., Conclusions: The general level of technical quality of coronary angiography is unsatisfactory. Variation in the interpretation of angiograms was substantial in all measures and tended to be higher in individual than in panel readings. The effect was to lead to a potential overestimation of appropriateness of use of CABG by 17% and of PTCA by 10%. These findings indicate the need for increased attention to the technical quality of studies and an independent second reading for angiograms before recommending revascularization.

We present a novel technique employing biplane cineangiography with simultaneous left coronary and pulmonary angiography to define the anomalous course of the left main coronary artery when it originates from the right sinus of Valsalva. These biplane cinearterlograms clearly define the relationship of the left main coronary artery to the great vessels, allowing confident delineation of the interarterial variant from the other, benign variants. We illustrate the advantages of this technique with two cases in which the course of the anomalous left main coronary artery was incorrectly diagnosed using standard coronary arteriography and magnetic resonance imaging.

Background: Development of the "all-digital" cardiac catheterization laboratory has been slowed by substantial computer archival and transfer requirements. Lossy data compression reduces this burden but creates irreversible changes in images, potentially impairing detection of clinically important angiographic features., Methods and Results: Fifty image sequences from 31 interventional procedures were viewed both in the original (uncompressed) state and after 15:1 lossy Joint Photographic Expert's Group (JPEG) compression. Experienced angiographers identified dissections, suspected thrombi, and coronary stents, and their results were compared with those from a consensus panel that served as a "gold standard." The panel and the individual observers reviewed the same image sequences 4 months after the first session to determine intraobserver variability. Intraobserver agreement for original images was not significantly different from that for compressed images (89.8% versus 89.5% for 600 pairs of observations in each group). Agreement of individual observers with the consensus panel was not significantly different for original images from that for compressed images (87.6% versus 87.3%; CIs for the difference, -4.0%, 4.0%). Subgroup analysis for each observer and for each detection task (dissection, suspected thrombus, and stent) revealed no significant difference in agreement., Conclusions: The identification of dissections, thrombi, and coronary stents is not substantially impaired by the application of 15:1 lossy JPEG compression to digital coronary angiograms. These data suggest that digital angiographic images compressed in this manner are acceptable for clinical decision-making.

Digital coronary angiographic techniques are now widely used in many cardiac catheterization laboratories. However, the full potential of digital imaging technology remains to be achieved because of its enormous storage and exchange requirements. Compression of digital imaging data allows a reduction in the volume of data so that storage and transmission are more efficient and cost-effective. Three angiographers reviewed the original and compressed formats of 96 coronary angiographic sequences in a blinded fashion to assess coronary lesion severity. Compression was achieved using the Joint Photographic Experts Group (JPEG) standard, which resulted in a compression ratio of approximately 15:1. The original format was reviewed in a blinded fashion a second time to assess for intraobserver variability of similar formats. Lesion severity was graded in quartiles. Coronary stenosis >50% was considered "significant." In parallel, the reproducibility of quantitative coronary angiographic (QCA) measurements of coronary artery dimensions was also evaluated. For the visual assessment of lesion severity in the compressed versus original formats, kappa=0.52, suggesting moderate agreement. When lesions were assessed as significant versus "insignificant," however, kappa=0.88, suggesting excellent agreement. In the 2 separate readings of the original data formats, kappa=0.44 for assessment of lesion severity by quartiles and kappa=0.72 for lesions assessed as significant versus insignificant. Analysis of the compressed versus original data sets using QCA resulted in an excellent correlation for the measurement of lesion severity (r=0.99). The correlation was equally strong when the original format was analyzed sequentially (r=0.98). Lossy JPEG (15:1) compression is a valid means for reducing storage and exchange requirements of coronary angiographic data. The variability in assessing lesion severity between the original and compressed formats is comparable to the reported variability in visual assessment of lesion severity in sequential analysis of cine film.

The accuracy and precision of a fully automated quantitative coronary angiography (QCA) algorithm for use in a cineless environment were determined in phantom studies and in an in vivo canine preparation. Imaging studies of 118 coronary segments in six anesthetized dogs were compared with measurements of the diameters of casts of the canine coronary arteries produced in physiologic conditions. Regression analysis of phantom vessel diameters against QCA measurements revealed slopes of 0.94 to 0.96 and r values > 0.99. The results of the in vivo studies showed good correlation with the coronary cast diameter measurements, with a slope of 0.969 and an r value of 0.987 for the sets of measurements. The high degree of accuracy obtained in a model representative of the clinical situation demonstrates that QCA methods can be applied reliably in the clinical arena with current digital imaging technology and without cinefilm.

Coronary angiography continues to be the pivotal study in the diagnosis and treatment of ischemic cardiac disease. Although angiographic equipment and imaging techniques have advanced over the past three decades, the analysis of coronary angiograms, by visual estimated percent diameter stenosis, has remained unchanged in most clinical catheterization laboratories. Rapid, computerized angiographic analysis systems are now available that remedy the inherent imprecision and inaccuracies plaguing visual coronary analysis. Despite its advantages, successful QCA is quite dependent on meticulous attention to radiographic and angiographic technique, even more so than with visual analysis. Although the available QCA systems can reproducibly and accurately define the site and degree of coronary stenosis, they cannot routinely determine whether an obstruction is flow limiting. Several methods, some based on extrapolations of quantitative measures alone, and others based on digital subtraction angiography, have been developed to determine the physiologic impact of a given coronary lesion. Recent observations have demonstrated, however, that even if the physiologic consequences of an obstruction are known, the prognosis of the lesion over time cannot be predicted. The qualitative, morphologic characteristics of a lesion are as, or more, important than the quantitative lesion attributes in determining an atheroma's behavior and stability, and hence, qualitative descriptors should be incorporated into QCA analyses. Although not currently available, future QCA systems will provide, by automated analysis, reproducible and accurate measures of absolute obstruction, physiologic data describing the flow limiting characteristics of a lesion, and qualitative, morphologic lesion descriptors. Implementation of these systems should provide more consistent and accurate prognostic and pathophysiologic information, thereby helping to refine and more effectively direct therapeutic interventions in coronary artery disease.

Using catheter outer diameter as a scaling device, quantitative coronary arteriography allows the precise and objective measurement of change in absolute dimensions of coronary arteries after mechanical or pharmacologic intervention. Because of variable density in the wall of the catheter, automated systems might vary in the determination of the outer catheter diameter. To examine this premise, catheters in a variety of French sizes from 6 manufacturers were injected with radiographic contrast and used as scaling devices for arterial phantoms of known geometric dimension. Radiographic diameters of the catheters were determined by applying the quantitative coronary arteriographic algorithm to the catheters using a calibration grid in the same field of view. The varying composition of the catheters resulted in differing x-ray attenuation and, subsequently, automated edge-detection algorithms varied widely in determining the actual catheter diameter to be used as a scaling factor. For instance, a Lucite "artery" with a minimal luminal diameter of 1.50 mm (image calibrated using the micrometer-determined outside diameter of a Baxter 8Fr guiding catheter) resulted in a quantitative angiographic diameter of 2.03 mm (overestimation by 35%). If the diameter of a similar size Shiley catheter was used to calibrate the image, a luminal diameter of 1.60 mm was determined: a difference of 0.43 mm based solely on differences in scaling catheter attenuation. These data suggest that a specific "fingerprint" for each catheter material and catheter French size exists, rendering generalizations about catheter size questionable. These observations are important for quantitative angiography where many brands and sizes of angiographic catheters are being used clinically.(ABSTRACT TRUNCATED AT 250 WORDS)

The accuracy of coronary artery diameter determination by digital angiography was assessed by imaging 39 coronary segments of excised dog and human hearts and comparing these segments with pathologic sections 0.76 to 3.31 mm in luminal diameter. Digital images were obtained postmortem both during contrast injection using a fixed-pressure coronary perfusion system and after fixation when the coronary size was maintained by injection of a barium-gelatin casting mixture. Digital data were analyzed with commercially available, automated edge-detection software using a coronary catheter as the calibration standard. Coronary diameter measured during contrast injection was not significantly different from that measured after casting and fixation. Digital data from both methods correlated well with diameters from pathologic sections (injected, r = 0.85; fixed, r = 0.91). Linear regression parameters comparing pathologic diameters with the contrast injection method were slope = 0.82, intercept = 0.42 mm, and standard error of the estimate = 0.27 mm. Parameters for the comparison of pathology with casted coronary data were slope = 0.95, intercept = 0.16 mm, and standard error of the estimate = 0.23 mm. Intra- and interobserver variability were 3% (0.05 mm) and 4% (0.07 mm), respectively. These data indicate that when a coronary catheter as a calibration standard is used, coronary artery dimensions can be accurately measured by automated digital angiography techniques.

The internal mammary artery has become the coronary bypass graft of choice in recent years because of enhanced long-term patency. Along with this trend, sequential, bilateral, and free mammary grafts have been employed more frequently in an effort to maximize the number of distal internal mammary anastomoses. This approach of maximally using the internal mammary artery (complex mammary grafting) seems logical, but at present little information about patency of the newer types of internal mammary artery grafts is available to justify the more complicated procedures. Over a 15 month period, 207 patients underwent bypass graft angiography from 1 to 32 weeks after operation. This is an 85% restudy rate for a consecutive series of coronary bypass procedures. Patency was defined as complete filling of the graft and distal vessel bypassed. A total of 841 distal vessels were grafted, or 4.1 per patient. The overall patency rate was 91% for 503 distal vein graft anastomoses and 99% for 338 internal mammary artery grafts. Individual patency rates of distal anastomoses, expressed as number patent/total (percent patent), were as follows: simple vein grafts, 262/285 (92%); sequential vein grafts, 196/218 (90%); left internal mammary artery to left anterior descending coronary artery, 109/110 (99%); left internal mammary to circumflex marginal artery, 14/14 (100%); right internal mammary to right coronary artery, 19/20 (95%); right internal mammary to left anterior descending coronary artery, 10/10 (100%); right internal mammary to circumflex marginal artery via transverse sinus, 18/20 (90%); sequential left internal mammary artery to left anterior descending system, 133/134 (99%); sequential left internal mammary to circumflex marginal system, 15/15 (100%); free internal mammary artery, 9/9 (100%); free sequential internal mammary artery, 6/6 (100%). Of the 18 patent transverse sinus right internal mammary grafts to the circumflex marginal artery, three exhibited very slow flow and probably were not functional. The hospital mortality associated with internal mammary revascularizations was 0.4% for nonemergency cases and 3.1% for emergency procedures. On the basis of clinical and postoperative graft patency data, expanded use of more complicated types of mammary grafts seems justified. Function of the right internal mammary graft to the circumflex marginal artery was suboptimal, and this method has been discontinued. All other complex mammary techniques had excellent patency rates as compared to vein grafts, and these differences may become even more significant in the late postoperative period.(ABSTRACT TRUNCATED AT 400 WORDS)