Gilles Hudon

A controlled clinical trial to assess the effect of a calcium channel blocker on the progression of coronary atherosclerosis.

To determine whether calcium channel blockers influence the progression of coronary atherosclerosis, 383 patients age 65 years or less with 5-75% stenoses in at least four coronary artery segments were selected at random within 1 month of coronary arteriography to participate in double-blind therapy with a placebo or nicardipine 30 mg three times daily. Coronary events (5 deaths, 22 myocardial infarctions, and 28 unstable anginas) occurred in 28 of 192 nicardipine patients and 23 of 191 placebo patients (p = NS). At 24 months coronary arteriography was repeated in 335 patients. Progression, defined as a 10% or more worsening in diameter stenosis, measured quantitatively, was found in 147 of 1,153 lesions (12.7%) in 168 nicardipine patients and in 170 of 1,170 lesions (14.5%) in 167 placebo patients (p = NS). Ninety-two nicardipine patients (55%) and 95 placebo patients (57%) had progression at one or more sites (p = NS). Regression, that is, an improvement by 10% or more in diameter stenosis, was seen in 140 of 2,323 lesions (6.0%) overall, with no significant intergroup difference. Among the 217 patients with 411 stenoses of 20% or less in the first study, such minimal lesions progressed in only 15 of 99 nicardipine patients compared with 32 of 118 placebo patients (15% versus 27%, p = 0.046). In this subgroup, 16 of 178 minimal lesions in nicardipine patients and 38 of 233 minimal lesions in placebo patients progressed (p = 0.038). By stepwise logistic-regression analysis, baseline systolic blood pressure (p = 0.04) and the change in systolic blood pressure between baseline and 6 months (p = 0.002) correlated with progression of minimal lesions. This suggested blood pressure reduction may account for the beneficial action of nicardipine. These results suggested nicardipine has no effect on advanced coronary atherosclerosis but may retard the progression of minimal lesions.

Definition and measurement of restenosis after successful coronary angioplasty : implications for clinical trials

Angiographic restenosis represents the most established measure of long-term outcome in most prospective clinical trials of coronary angioplasty (PTCA). The accuracy of assessing this endpoint is of utmost importance. The purpose of this article is to propose guidelines for the use of coronary angiography in this setting. First, the cineangiograms must be of high technical quality and performed in a high proportion of consecutive patients in follow-up under controlled study conditions that are reproducible. Second, computer-assisted quantitative coronary angiographic analysis is essential to minimize interobserver and intraobserver variability in stenosis measurement between successive studies. The following recommendations are presented for quantitative coronary angiographic analysis. Because biplane orthogonal views cannot always be performed both at baseline and at follow-up, stenosis measurement in the single-plane, most severe view often constitutes the most consistent and practical approach. The edge-detection method is still much more reproducible and accurate than densitometry and should be the preferred method of analysis. Measurement of reference diameter by the interpolated method is more objective than measurement by the user-defined approach and should be used whenever possible. Finally, measurements of absolute minimum diameter and percent diameter stenosis are both important in the assessment of outcome in clinical trials. Absolute minimum diameters are independent of variations in reference diameter, and the extent of reduction in minimum diameter between the immediate postangioplasty and follow-up angiograms, when expressed in dichotomous or continuous fashion, accurately defines the extent of vessel wall hyperplasia as an endpoint. On the other hand, vessel size corresponds in general to the size of myocardium subserved, and absolute changes do not take into account this physiologic fact. Therefore defining restenosis in terms of significant reduction in percent diameter stenosis is also a useful approach because of its clinical relevance. Thus clinical restenosis requires that a successfully dilated segment (< 50% diameter stenosis) show a > or = 50% diameter stenosis at follow-up angiography with, in addition, a meaningful degree of change, that is, exceeding 2 SDs of observer variability in quantitative measurements which, in our experience, translates into > or = 15% difference between early postangioplasty and follow-up angiography measurements.

Transluminal angioplasty of the subclavian artery in patients with internal mammary grafts.

From January 1987 to January 1992, 11 patients underwent percutaneous transluminal angioplasty (PTA) for the treatment of subclavian artery stenosis before or after coronary artery bypass grafting (CABG) using the internal mammary artery (IMA). There were 8 men and 3 women, with a mean age of 57 +/- 7 years. Four patients had PTA 1 to 4 months before undergoing CABG with IMA grafts, because of either asymptomatic supraclavicular murmurs or neurologic symptoms. Seven patients underwent PTA 2 to 37 months after CABG with IMA grafts, because of recurrent angina. Subclavian artery stenosis was on the left side in 9 patients, the right side in 1 patient, and bilateral in 1 patient. Ten PTA procedures were successful in 9 patients. All patients with post-CABG angina had reversal of the ischemia. There were three complications: one femoral artery thrombosis, one brachial plexus hematoma after an axillary approach, and one acute pulmonary edema after the procedure. Follow-up after PTA ranged from 1 to 60 months (mean, 38 +/- 17 months). Nine patients had no angina at follow-up and 2 had stable angina (class II) upon exertion. Upper-limb Doppler studies showed no evidence of restenosis in any of these patients at a mean follow-up of 38 months. Subclavian artery PTA is a useful alternative to IMA bypass grafting in patients with subclavian artery stenosis discovered preoperatively, and it is the treatment of choice for those presenting with post-CABG angina due to subclavian artery stenosis proximal to an IMA graft.

Early and long-term results of percutaneous transluminal angioplasty of the lower abdominal aorta

PURPOSE The purpose of this study was to determine the early and long-term results of percutaneous transluminal angioplasty (PTA) of atherosclerotic lower abdominal aorta stenosis. METHODS This study was performed as a retrospective study. From 1980 to 1997, 46 patients with chronic lower limb ischemia with moderate to severe claudication as the result of isolated infrarenal disease or aortoiliac disease underwent PTA. All patients underwent angiography before and after angioplasty and Doppler ultrasound scan examination with ankle-brachial index determination. No stents were used. RESULTS The technical success rate was 96% (44 of 46 cases). Thirty-eight patients (83%) immediately showed clinical, hemodynamic, and angiographic improvement. The initial success rate for patients with isolated infrarenal or bifurcation disease was 92%, whereas it was 71% for aortoiliac disease. Among the eight patients with no initial improvement, four had clinical deterioration and two required emergency surgical revascularization. There were no other complications. Fifty-six percent of the patient conditions (95% confidence interval [CI], 38% to 74%) remained clinically improved at the 5-year follow-up examination. Recurrence of symptoms was caused by femoropopliteal disease in most patients. The primary patency rate assumed with maintenance of hemodynamic improvements was 70% (95% CI, 52% to 88%) and 64% (95% CI, 44% to 84%) at 4 and 5 years of follow-up, respectively. The primary patency rate at 4 years for patients with isolated infrarenal or bifurcation disease was 83% (95% CI, 64% to 100%), whereas it was 55% for aortoiliac disease (95% CI, 30% to 80%; P =.06) The variables that were statistically predictive of patency failure were poor runoff (P =. 01) and presence of aortoiliac atherosclerotic disease (P =.04). CONCLUSION Our results suggest that PTA is an excellent treatment for chronic arterial insufficiency of the lower extremities as the result of isolated atherosclerotic lower abdominal aortic occlusive lesions because of good long-term patency. Aortic PTA for those patients with iliac involvement or with poor runoff gives acceptable results but carries lower patency and clinical success rates.

Comparison of ionic and nonionic low osmolar contrast media in relation to thrombotic complications of angioplasty in patients with unstable angina.

BACKGROUND Acute complications of percutaneous transluminal coronary angioplasty (PTCA) are more common in patients with unstable coronary syndromes. The objective of this study was to prospectively determine the differences between ionic and nonionic low osmolar contrast media (LOCM) on potential risk of acute complications, particularly abrupt vessel closure, in patients with unstable angina undergoing PTCA. METHODS A total of 210 patients with 278 lesions were randomized to receive either ionic or nonionic LOCM during PTCA. Quantitative coronary angiographic measurements and assessment of filling defects were made by experienced observers who were blinded to the type of contrast media used. RESULTS The baseline clinical and angiographic characteristics, the immediate postangioplasty results, and clinical outcome were similar in both groups. Subacute recoil, defined as the difference between minimal luminal diameter (in millimeters) at 0 and 15 minutes after angioplasty, was significantly greater in patients receiving nonionic LOCM (0.17 +/- 0.36 mm vs 0.07 +/- 0.18 mm, p = 0.004). A filling defect abnormality attributable to dissection, thrombus, or a combination of the two was noted in similar proportions of the two groups. Although nonsignificant, more thrombus was noted in the nonionic group (21 of 129 vs 15 of 141, p = NS). The abrupt vessel closure rate was similar in the two groups and was only 1.9% in the first 24 hours. However, 17 (8.3%) patients had a repeat PTCA at 15 minutes (9 ionic vs 8 nonionic). CONCLUSION In patients with unstable angina the choice of ionic or nonionic LOCM does not appear to significantly affect the clinical outcome of PTCA.

Mycotic aneurysm of the palmar arch after endocarditis

Mycotic pseudoaneurysms of upper extremities are an infrequent complication of endocarditis. We describe a case of mycotic pseudoaneurysm of the superficial palmar arch in a patient who had acute bacterial endocarditis. We discuss operative and pathologic findings and briefly review the literature on the subject.

Issues in the performance of quantitative coronary angiography in clinical research trials

Quantitative coronary analysis remains the classical and most commonly used tool to assess the results of coronary pharmacological or mechanical intervention. The authors review the methodology of this type of analysis, highlighting the pros and cons of previous recommendations. Special interest has been devoted to catheter calibration and the choice of angiographic views for optimal measurement and reliability. Significant additional information in terms of acute gain, late loss or restenosis rate is not gained by the use of averaged orthogonal measurements as compared to the more simple single view approach. Also calibration procedures can be simplified by using tables of mean measured values for various types of catheters instead of measuring each catheter with a precision micrometer and by doing calibration measurements on contrast filled instead of flushed catheters. Moreover, specific in vitro and in vivo criteria have been proposed and tested for acceptance of catheter type and size in QCA analyses. Based on these criteria only catheters of sufficient size (6F or greater) and approved for QCA are recommended.

Validation of coronary artery saphenous vein bypass graft diameter measurements using quantitative angiography

The accepted value for reproducibility (true change) is two standard deviations (SD) of the differences between repeat measurements. It has been well established for coronary artery measurements using several different quantitative coronary angiography (QCA) systems, but it has not been well documented for saphenous vein grafts (SVG). The purpose of this study was to assess, using the Cardiovascular Measurement System (CMS), the measurement reproducibility of 24 vein grafts from 24 patients who had symptom-directed control angiography. Three equal graft segments were studied separately. Focal narrowings expressed in percent stenosis varied from 5 to 80% (mean 20.8±15.9%). The average minimum lumen diameter (MLD) was 3.07±0.81 mm and the average interpolated reference diameter (Ref.D) was 3.87±0.58 mm. We assessed the reproducibility of measurements obtained from two separate imagings of the graft in the same view but at least 20 minutes apart, near the beginning and at the end of the angiographic procedure (simulating baseline and end-trial examinations). The SD for differences in measurements (variability) was 0.183 mm for the MLD, 0.193 mm for the Ref.D, 0.184 mm for the mean diameter (Mean D) and 3.72% for the percent diameter stenosis (PDS).A reasonable true change cut-off for SVG measurements in our laboratory is ≥ 0.4 mm for the minimum and mean lumen diameters, and ≥ 10% for the PDS, when QCA is obtained with the QCA-CMS analytical software package.

A new look at coronary angiograms: plaque morphology as a help to diagnosis and to evaluate outcome

Characterization of plaque morphology can provide useful information beyond those generally yielded by the more traditional methods of interpretation of coronary angiograms based on assessment of severity of stenoses and number of diseased vessels. Focus on the culprit coronary lesion in acute myocardial infarction and in unstable angina allows recognition of the complex plaque and of presence of endoluminal thrombi that are closely associated to the mechanisms of the disease. Response to treatment in these clinical situations, and the healing process can be assessed by repeated opacifications of the lesion. The presence of a residual thrombus is associated with a worse clinical outcome and also a higher risk of complication if coronary angioplasty is performed. The prognostic information derived from the morphologic analysis extends to the chronic phase of the disease. The extent score of disease, defined as the sum of coronary artery segments showing a narrowing of any severity marks more severe disease and predicts future progression. Severity of stenosis is also a predictor. More severe lesions will occlude more frequently but most often without clinical consequences. Occlusion of less severe stenosis, on the other hand, leads to acute myocardial infarction or to the other manifestations of acute coronary syndromes. Other morphologic features are also associated with a higher risk of myocardial infarction. These include a geometry favoring blood flow separation and turbulence such as acute inflow and outflow angles of the stenosis and presence of a division within its vicinity. This new look at coronary angiograms may help orient therapy. Patients with angina and a significant stenosis will profit from a corrective intervention. Others with a high extent score should receive a comprehensive program for control of risk factors. Patients with a lesion of borderline significance at risk of activation should be closely monitored, and when clinical symptoms evolve, receive more intensive antithrombotic therapy. Quantification of the morphologic characteristics of the plaque, coupled to new techniques for endovascular imaging should lead in the future to better diagnostic and better risk stratification.

Are qualitative features of coronary artery lesions useful in predicting progression

Morphologic characterization of coronary artery lesions can provide useful information on clinical stability, pathophysiologic mechanisms and prognosis, beyond that provided by the traditional interpretation of coronary angiography in terms of lesion severity and number of diseased arteries. Thus, more numerous lesions, defined by a higher extent score,’are associated with a more progressive disease and a worse prognosis. Lesions of only moderate severity, but with a geometry favoring flow separation carry a higher risk of thrombotic occlusion and myocardial infarction. More severe lesions occlude more, but often without symptoms. The acute process is characterized by a complex plaque with eccentricity, steep inflow angle, ulcerations and with filling defects by partially or completely occluding thrombi. Subsequent remodeling leads to lesion progression with edge irregularities. A residual thrombus is associated with a higher risk of recurrent coronary events and also of procedural complications during angioplasty.