Primary coronary angioplasty was attempted in 288 patients (206 men and 82 women) who presented with stable (50%) or unstable (50%) angina pectoris. The success rates of angioplasty and the subsequent revascularization requirements in these two angina categories were compared during a one year prospective follow‐up. The site and distribution of coronary artery stenoses did not differ between the categories. Three hundred and five dilatations were attempted (149 in 144 patients with unstable angina and 156 in 144 patients with stable angina). Of these procedures, 265 (87%) were technically successful — 133 (89%) in 128 patients with unstable angina and 132 (85%) in 120 patients with stable angina. Lower success rates were achieved in 29 attempted dilatations of vessels with chronic total occlusion (19 successful [66%], P = 0.002) and in 19 patients who presented with unstable angina after recent (within two weeks) infarction (10 patients with successful angioplasty, [53%], P < 0.0001). Subsequent revascularization requirements after an initially successful angioplasty in 57 patients were greater in unstable (36 patients) than in stable angina (21 patients; P= 0.05) and reflected the greater frequency of repeat angioplasty in patients with unstable angina (22 patients) compared with those with stable angina (10 patients; P = 0.04) among patients with recurrent symptoms. At one year, 245 patients (85%) — 121 treated for unstable angina and 124 treated for stable angina — experienced no angina during normal daily activities. We conclude that a primary angioplasty success rate of 89% can be achieved in patients with unstable angina pectoris but this rate is significantly lower in patients presenting after recent infarction. Repeat angioplasty for recurrent symptoms after a successful primary procedure is required more frequently in patients presenting with unstable angina.

A multivariate predictive model for early (six-month) survival based on Cox's proportional-hazards regression model was developed using data collected prospectively from 317 consecutive patients admitted with acute myocardial infarction to a coronary care unit (CCU). Of these, 63 (19.8%) died within the follow-up period. Patients with cardiogenic shock were excluded from the study. Variables associated with survival were sought from clinical, historical, electrocardiographic and radiographic variables recorded at the time of admission. On multivariate analysis, a stepwise selection procedure identified four variables which described the probability of survival for the six-month follow-up. These were: age, upper lung crepitations, marginal and also definite radiographic cardiomegaly on an anteroposterior radiograph. With this combination of clinical variables alone, using a survival probability partition value of 80%, the model had a sensitivity of 67% and a specificity of 75%. However, the model's predictive accuracy for death was 40%, compared to a predictive accuracy for survival of 90%. This clinical model is most useful for early discrimination of those patients at low risk of death within six months of CCU admission. Other predictive tests for premature death would need to exceed these discriminatory criteria to justify their cost and risks.