Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease. Report of the Collaborative Study in Coronary Artery Surgery (CASS).

The 3 year cumulative survival rate of 1,492 patients with left main coronary artery disease (50 percent or greater stenosis of luminal diameter) enrolled in the Collaborative Study in Coronary Artery Surgery (CASS) was 91 percent for the surgical group and 69 percent for patients treated medically (p less than 0.0001). Mortality was significantly greater in patients with impaired left ventricular function. The difference between medical and surgical therapy was significant for patients who had normal, moderately abnormal and severely impaired left ventricular function and for patients with stenosis of the left main coronary artery of 50 to 59, 60 to 69, 70 to 79 and 80 percent or greater. Aortocoronary bypass surgery did not significantly improve survival in patient subgroups who had (1) a nonstenotic dominant right or balanced coronary circulation, (2) a stenotic dominant right coronary artery and normal left ventricular function, and (3) left main coronary stenosis of 50 to 59 percent and normal or mildly abnormal left ventricular function. The Cox proportional hazards model was used to select baseline variables that were independent predictors of long-time mortality. The model selected left ventricular score, age, congestive heart failure score, hypertension, percent left main coronary arterial stenosis and coronary arterial dominance as the baseline variables most predictive of long-term survival. A clinical and angiographic prognostic risk index developed from these six baseline variables showed significantly improved survival for the surgical cohort in each of four risk categories. In the best and worst risk category, the 3 year survival rate was 97 and 82 percent, respectively, for the surgical group and 85 and 34 percent, respectively, for the medical group (p less than or equal to 0.0002). The data from this observational study show that coronary bypass surgery prolongs life in most patients with left main coronary artery disease, particularly those who have severe narrowing of the left main coronary artery or impaired left ventricular function. The results permit a better understanding of the natural history of left main coronary artery disease and permit a more accurate estimate of long-term survival for individual patients through the use of a clinical-angiographic risk index.

Design of comparative clinical studies of percutaneous transluminal coronary angioplasty using estimates from the Coronary Artery Surgery Study.

The design of a prospective randomized trial of PTCA is discussed. It is suggested that patients with proximal subtotal occlusion of 1 or more vessels may be candidates for such a trial. Medical therapy as a control of 1-vessel CAD, medical or surgical therapy as a control for 2-vessel CAD (with 1 dilatable vessel) cases and surgical therapy as a control for 3-vessel CAD are most congruent with current practice. Possible criteria for comparison of PTCA with a control therapy include vital status, angina with daily activities, angina upon maximal exercise testing, MI, hospitalization, work status, cost, follow-up angiographic assessment, follow-up radionuclide ventriculography, measurement of immediate anatomic or hemodynamic change during initial treatment and quality-of-life indexes. These 10 measures are evaluated with respect to 9 desirable attributes for outcome criteria: the importance of the quantity measured, reproducibility, accuracy, low influence of investigator bias, low influence of subject bias, the measure is inexpensive and easy to obtain, sufficient occurrence to detect important differences, convenient to patients and measuring impairment due to disease. Examination of data from the Coronary Artery Surgery Study suggests that (1) a trial based on mortality alone is not feasible (because of a needed sample size in the thousands); (2) a trial using a combined death and/or MI end point would need approximately 1,000 cases even for patients with multivessel CAD; (3) approximately 950 patients would be needed in a trial to evaluate return to work (within 10%); (4) a trial based on pain relief (within 15% of the control group) would need 500 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Particulate myocardial perfusion scintigraphy: its clinical usefulness in evaluation of coronary artery disease.

The determination of myocardial viability is a crucial parameter in the evaluation of a patient with coronary artery disease. Particulate myocardial perfusion scintigraphy (PMPS) is one of several methods available for this determination. A brief comparison between PMPS and two other commonly used methods is described in this review. The technique and analysis are described and applied to 194 patients with 366 surgically bypassed regions. The patients are analyzed for postoperative regional wall function and for total ventricular function as expressed by ejection fraction. PMPS is a highly accurate and unique study for clinically predicting myocardial viability.

[Variability in the interpretation of coronary angiograms by different specialists based on data from the cooperative Coronary Artery Surgery Study]. / Variabel'nost' interpretatsii koronarnykh angiogramm raznymi spetsialistami po dannym Kooperativnogo izucheniia khirurgicheskogo lecheniia koronarnykh arterii.

Randomly selected cine arteriographic films of 30 diseased patients were read twice by each of three experienced observers. The intrareader variability was less than one-half of the interreader variability in reading the stenosis of segments of the coronary anatomy - a statistically significant difference (p less than 0.001). When extent of disease was evaluated by the number of diseased vessels, interreader variability was larger than intrareader variability (p less than 0.01). One reader read considerably less disease than the other two readers. The films were rated as to quality of the arteriographic films and the completeness of the study. In each case there was a greater interreader than intrareader variability (p less than 0.01). The films were rated good, acceptable, or poor. One of the three interpreters consistently gave worse ratings than the other two readers. It was particularly noteworthy that a larger amount of interreader variability was observed in both the left main coronary artery and the proximal left anterior descending artery.

[Comparison of the cumulative survival among patient groups with a left main coronary artery lesion after surgical and therapeutic treatment]. / Sravnenie sovokupnoi vyzhivaemosti sredi grupp patsientov s porazheniem glavnogo stvola levoi koronarnoi arterii posle operativnogo i terapevticheskogo lecheniia.

In order to evaluate survival patterns in patients with left main coronary artery (LMCA) disease, 1492 patients with LMCA disease admitted to the U. S. Collaborative Study on Coronary Artery Surgery (CASS) were followed up. Of the 1492 patients, 1183 (79%) underwent coronary artery bypass (CABG) with an operative mortality of 4.2% and an average of 2.7 grafts/patient inserted. Allocation to surgery was by patient and physician preference and not random. Surgical patients generally had more severe angina, a higher prevalence of beta blocker usage, worse ventricular function and more severe LMCA stenosis than medically treated patients. Overall (4 years) survival of the surgical group was 88% compared to 63% in the medical group (p less than 0.001). Other independent predictors of mortality included angiographic left ventricular (LV) dysfunction score, age, % LMCA stenosis, hypertension, dominance, and presence of significant right coronary artery (RCA) stenosis greater than or equal to 50%. CABG was not shown to significantly improve survival in women, in LMCA patients with left dominant circulation, in LMCA patients with non-diseases dominant or balanced RCA circulation or in LMCA patients with greater than or equal to 50% RCA stenosis but good LV function. These data indicate that CABG prolongs life in most patients with left main coronary artery disease, particularly those with severe LMCA narrowing or severe LV dysfunction, however, subgroups of LMCA patients are identifiable who may fare with medical treatment alone.

Guidelines for radiation protection in the cardiac catheterization laboratory.

Even though radiation levels in the catheterization laboratory are the highest encountered during any commonly performed diagnostic study, dose levels to laboratory personnel should not approach the maximum permissible. A certain minimum amount of radiation is necessary to produce optimal diagnostic images. Therefore, optimum use of radiation protection devices and measures is essential. The goal should be dose minimization, keeping personnel radiation dose as low as reasonably achievable. In the cardiac angiographic suite this goal can be assumed to have been accomplished if: (1) maximum use is made of suitable radiation protection devices, (2) film-and video-imaging chains are optimized, (3) good radiographic technique is employed, (4) strict ongoing quality control programs are maintained for radiographic equipment and cine processor, and (5) there is compliance with all federal, state and local regulations for the safe use of ionizing radiation.

Coronary bypass surgery in Prinzmetal angina.

A case of Prinzmetal angina, characterized by spontaneous attacks of chest pain associated with hypotension, inferior wall ST-segment elevation, and transient second degree A-V block, is presented in which coronary arteriography demonstrated spasm of the right coronary artery. Aortocoronary bypass surgery, a questionable approach in the treatment of this entity, afforded complete symptomatic relief. The multiple problems inherent in selecting patients and proper operative technique are discussed.

[Proceedings: Studies on myocardial perfusion by means of marked particles, injected selectively into the coronary system: an aid in preoperative evaluation of patients with coronary sclerosis]. / Studien der myokardialen Perfusion mittels markierter, selektiv ins Koronarsystem injizierter Partikel: eine Hilfe in der präoperativen Beurteilung von Patienten mit Koronarsklerose

Myocardial color scintigraphy using macroaggregates labeled with 99mTc and 131I were performed in patients with coronary heart disease. The particles were injected selectively into the coronary arteries. The scintigram was obtained using a color coded display system. The channel with the maximum counts was assigned the color red and each 10% change resulted in a different color. A count rate below 40% of the maximum was considered inadequate. 80 patients undergoing coronary surgery were evaluated postoperatively. Postoperative ventriculography documented improved contractions in 34 of 40 ventricular segments (85%) in which preoperatively an adequate perfusion was observed, whereas in only 13 out of 42 segments with preoperatively inadequate perfusion was an improvement in ventricular contractility observed.

Complications of coronary arteriography from the Collaborative Study of Coronary Artery Surgery (CASS).

Data were collected prospectively on 7553 consecutive patients undergoing coronary arteriography. The studies were performed at 13 clinics of the Collaborative Study of Coronary Artery Surgery (CASS) using brachial and femoral techniques. There were eight deaths 0--24 hours and seven deaths 24--48 hours after arteriography (2/1000). There were 15 non-fatal myocardial infarctions (MIs) 0--24 hours and four MIs 24--48 hours after arteriography (2.5/1000). Of 657 cases with left main stenosis greater than or equal to 50%, five died and three had MI. Left main disease increased risk of death by 6.8 times (p less than 0.001). Other factors increasing risk were unstable angina, congestive heart failure, multiple premature ventricular contractions, and hypertension. Of the 1187 patients studied from the brachial artery, six died (0.51%) and five had MIs (0.42%). In 6328 patients studied from the femoral artery, nine died (0.14%) and 14 had MIs (0.22%). The brachial artery technique increased the risk of death 3.6 times compared with the femoral approach (p less than 0.05). This result did not apply when analysis was restricted to laboratories with 80% or more brachial procedures. Risk was not altered by heparin. Thus, a prospective, multicenter analysis of complications reveals low risk of coronary arteriography but significant difference between two techniques.

Aneurysmal coronary artery disease.

To examine the clinical and historical features and the natural history of aneurysmal coronary disease, we reviewed the registry data of the Coronary Artery Surgery Study (CASS). Nine hundred seventy-eight patients, representing 4.9% of the total registry population, were identified as having aneurysmal disease. No significant differences were noted between aneurysmal and nonaneurysmal coronary disease patients when features such as hypertension, diabetes, lipid abnormalities, family history, cigarette consumption, incidence of documented myocardial infarction, presence and severity of angina, and presence of peripheral vascular disease were examined. In addition, no difference in 5-year medical survival was noted between these two groups. These findings suggest that aneurysmal coronary disease does not represent a distinct clinical entity but is, rather, a variant of coronary atherosclerosis.