Kathryn B. Davis

Survival of medically treated patients in the coronary artery surgery study (CASS) registry.

The objective of this study was to evaluate the impact on survival of the anatomic extent of obstructive coronary artery disease and of two measures of left ventricular (LV) performance. This study is based on 20,088 patients without previous coronary artery bypass graft surgery who were enrolled in the registry of the National Heart, Lung, and Blood Institute Coronary Artery Surgery Study from 1975 to 1979. The cumulative 4-year survival of medically managed patients was analyzed to determine the survival of specific subsets of patients with obstructive coronary disease. The vital status of 99.8% of the patients was known. The 4-year survival of medically treated patients with no significant obstructive disease was 97%, in contrast to 92%, 84% and 68% in patients with one-, two- and three-vessel disease, respectively. The presence of left main coronary artery disease decreased survival significantly. The 4-year survival decreased from 70% to 60% in patients with three-vessel disease when significant obstruction of the left main coronary artery was also present. Patients with significant coronary artery disease who had an ejection fraction of 50-100%o, 35-49%, and 0-34% had a 4-year survival of 92%, 83% and 58%, respectively. The systolic contraction pattern was assessed in five selected segments and given a score of 1-6, with a score of I for normal function, increasing to 6 if an aneurysm was present. In a patient with normal LV contraction in all five segments of the LV ventricular angiogram, the LV score would equal 5. Patients with an LV score of 5-11, 12-16 and 17-30 had 4-year survivals of 90%, 71% and 53%, respectively. Patients with good LV function (a score of 5-11) had a 4-year survival of 94%, 91% and 79% for one-, two- and three-vessel disease, respectively. Patients with poor left ventricular function (score of 17-30) had a 4-year survival rate of 67%, 61% and 42% in one-, two- and three-vessel disease, respectivelv. Thus, LV function is a more important predictor of survival than the number of diseased vessels.

Coronary Bypass Surgery with Internal-Thoracic-Artery Grafts — Effects on Survival over a 15-Year Period

BACKGROUND Aortocoronary bypass surgery has been performed most often with the patients saphenous vein as the conduit. The internal-thoracic-artery graft, which has superior patency rates, has been shown to have clinical advantages, but it is not known how long these advantages persist. METHODS We identified all the patients in the registry of the Coronary Artery Surgery Study who had undergone first-time coronary-artery bypass grafting. Those with internal-thoracic-artery bypass grafts (749 patients) were compared with those with saphenous-vein bypass grafts only (4888 patients) with respect to survival over a 15-year follow-up period. RESULTS In a multivariate analysis to account for differences between the two groups, the presence of an internal-thoracic-artery graft was an independent predictor of improved survival and was associated with a relative risk of dying of 0.73 (95 percent confidence interval, 0.64 to 0.83). This improved survival was also observed in subgroups including patients 65 years of age or older, both men and women, and patients with impaired ventricular function. The survival curves of the two groups showed further separation over the years of follow-up, with a more marked downsloping after eight years in the curve for the group with saphenous-vein grafts only than in that for the group with internal-thoracic-artery grafts. CONCLUSIONS As compared with saphenous-vein coronary bypass grafts, internal-thoracic-artery grafts conferred a survival advantage throughout a 15-year follow-up period. The survival advantage increased with time, suggesting that the initial selection of the conduit was a more important factor in survival than problems appearing long after surgery, such as the progression of coronary disease.

Western Washington Randomized Trial of Intracoronary Streptokinase in Acute Myocardial Infarction

Two hundred fifty patients were enrolled in a multicenter, community-based study of the efficacy of intracoronary streptokinase thrombolysis in acute myocardial infarction; 134 were randomly assigned to streptokinase therapy and 116 were controls. All patients underwent left ventricular angiography and coronary arteriography before the random assignment. The mean time from the onset of symptoms to hospitalization was 134 +/- 144 minutes (S.D), and the mean time to random assignment was 276 +/- 185 minutes. Coronary reperfusion was achieved in 68 per cent of the streptokinase-treated group. The overall 30-day mortality was 18 (7.2 per cent); there were five deaths in the streptokinase-treated group (3.7 per cent) and 13 in the control group (11.2 per cent, P less than 0.02). Fifteen of the 18 deaths occurred in patients with anterior infarction. Intracoronary streptokinase therapy resulted in a nearly threefold reduction in the 30-day mortality after hospitalization for acute myocardial infarction.

A randomized trial of coronary artery bypass surgery: survival of patients with a low ejection fraction

The Coronary Artery Surgery Study (CASS) was designed to compare medical and surgical treatment of selected patients with chronic, stable coronary artery disease. This report concerns a subset of patients with reduced ventricular function. Of 780 patients randomly assigned to medical or surgical treatment, 160 had ejection fractions above 0.34 but below 0.50 at base line and have been followed for an average of seven years. Eighty-two patients were assigned to medical therapy, and 78 to surgery; the two groups were comparable at base line with regard to prognostically important variables. At seven years, 84 per cent of patients in the surgical group were alive, as compared with 70 per cent of the medical group (P = 0.01). Nearly half the patients with impaired ventricular function had triple-vessel disease at entry; at seven years, observed survival in this group was 88 and 65 per cent for those assigned to surgical and medical treatment, respectively (P = 0.009). Survival of patients with single-vessel or double-vessel disease was similar in the two treatment groups. We conclude that patients with triple-vessel disease and ejection fractions higher than 0.34 but lower than 0.50 appear to have improved seven-year survival with elective bypass surgery.

Long-term survival of medically treated patients in the Coronary Artery Surgery Study (CASS) Registry.

BackgroundThis study describes the impact of clinical, angiographic, and demographic characteristics on the long-term survival of Coronary Artery Surgery Study (CASS) patients while they were under medical treatment. Revascularization rates for the population are also provided. Methods and ResultsAll CASS patients who had not received heart surgery before enrollment (23467 patients) were included in this survival analysis while they were under medical treatment or surveillance. Follow-up time ranged from 0 to 17 years (median, 12 years). Long-term vital status is known for 95.8% of these patients. Log-rank tests, Kaplan-Meier survival curves, and Cox proportional- hazards regression are used to describe and assess the impact of patient characteristics on survival. Characteristics that had a significant impact on survival, in order of observed explanatory power, are age, number of diseased vessels, congestive heart failure score, smoking history, ejection fraction, sex, presence of left main coronary artery disease, presence of diabetes, left ventricular wall motion score, presence of other illnesses, history of myocardial infarction, and presence of left main equivalent disease. Overall, 12-year survival for patients with zero-, one-, two- and three-vessel disease is 88%, 74%, 59%, and 40%, respectively. Twelve-year survival for patients with at least one diseased vessel and ejection fractions in the ranges of 50% to 100%, 35% to 49%, and 0% to 34% is 73%, 54%, and 21%, respectively. High myocardial jeopardy, high anginal class, and two or three proximal diseased vessels characterize the profile of patients most likely to have received surgical treatment during follow-up. ConclusionsThese results contribute to the understanding of the natural history of coronary artery disease and are also of historical interest. The poor survival of patients with three-vessel disease and low ejection fractions continues to emphasize the importance of considering revascularization for these patients.

Angiographic prevalence of high-risk coronary artery disease in patient subsets (CASS).

The prevalence of coronary artery stenoses 2 70% or left main stenosis > 50% was evaluated in 20,391 patients who underwent angiography in the Coronary Artery Surgery Study from 1975-1979. After the patients with unstable angina or myocardial infarction were excluded, the disease prevalence in the 8157 patients with definite angina, probable angina, and nonspecific chest pain was 93%, 66% and 14% in men and 72%, 36% and 6% in women (p < 0.001).The age and sex of the patients and character of chest pain were important determinants of disease prevalence and severity. Left main or three-vessel coronary disease occurred in more than 50% of middle-aged men and older women with definite angina and in more than 50% of men who had probable angina and were older than 60 years of age. In contrast, left main coronary disease occurred in less than 2% of 1282 men and less than 1% of 1397 women with nonspecific chest pain regardless of age. In this latter patient subset, less than 5% of men and less than 1% of women in each decade under 60 years had left main or three-vessel coronary artery disease.Thus, high-risk coronary disease is common in middle-aged patients with definite angina and older patients with probable angina, but is rare in patients with nonspecific chest pain. Indications and guidelines for diagnostic noninvasive tests and coronary angiography could be based on these results.

The Western Washington randomized trial of intracoronary streptokinase in acute myocardial infarction. A 12-month follow-up report

After cardiac catheterization and coronary arteriography, 134 patients who had had an acute myocardial infarction were randomly assigned to treatment with intracoronary streptokinase (4000 U per minute, begun approximately 4 1/2 hours after the onset of symptoms, for a total of 286,000 +/- 77,800 U over 72 +/- 24 minutes); 116 control patients received standard care after they returned to the coronary care unit, immediately after angiography. Preliminary results of this trial have been published in the Journal (1983; 309:1477-81). During the first 30 days, 5 deaths occurred in the streptokinase group and 13 occurred in the control group (3.7 vs 11.2 per cent, P = 0.02); during the first year, the corresponding figures were 11 and 17 deaths (8.2 vs. 14.7 per cent, P = 0.10). However, when a minor imbalance in the ejection fraction and infarct location between the two groups was adjusted by logistic regression, the difference in one-year mortality became significant (P = 0.03). In the streptokinase group, 2 of the 80 patients in whom perfusion was reestablished (2.5 per cent) had died by one year, whereas 3 of the 13 with partial reperfusion (23.1 per cent) and 6 of the 41 with no reperfusion (14.6 per cent) had died (P = 0.008). Mortality among patients with partial reperfusion was not significantly different from that among those without reperfusion (P greater than 0.90). No base-line clinical, angiographic, or hemodynamic variable was predictive of successful reperfusion, according to univariate and multivariate analyses. We conclude that intracoronary streptokinase reduces one-year mortality among patients with acute myocardial infarction, but this improvement occurs only among those in whom thrombolysis results in coronary artery reperfusion.

Comparison of Surgical and Medical Group Survival in Patients With Left Main Equivalent Coronary Artery Disease

BACKGROUND Observational and randomized studies designed to compare surgical and medical therapies in patients with left main coronary artery disease (LMCD) have shown that coronary artery bypass graft (CABG) surgery prolongs life in most patients with LMCD. The present report of 1484 patients with LMCD in the Coronary Artery Surgery Study (CASS) Registry extends the originally published 5-year surgical and medical group survival analysis to more than 16 years of follow-up and permits analysis of LMCD patient subgroups. METHODS AND RESULTS The CASS Registry contains 1484 patients with > or = 50% left main coronary artery stenosis initially treated with either surgical or nonsurgical therapy. The 15-year cumulative survival estimates were 37% for the 1153 patients in the surgical group compared with 27% for the 331 patients in the medical group. Median survival in the surgical group was 13.3 years (12.8 to 13.8 years, 95% confidence limits) compared with only 6.6 years (5.4 to 7.9 years) in the medical group (difference, 6.7 years; P < .0001). Median survival was also significantly longer in the surgical group stratified by age, sex, anginal class, left ventricular (LV) function, coronary anatomy, and the extent of LMCD. However, CABG surgery did not significantly prolong median survival in patient subgroups with (1) left main coronary stenosis of 50% to 59%; (2) normal LV systolic function; (3) normal or mildly abnormal LV systolic function and a right coronary artery stenosis > or = 70%; and (4) a nonstenotic (< or = 70%) right coronary artery. The 15-year cumulative survival for patients with normal LV systolic function in the surgical and medical groups was 42% and 51%, respectively. Median survival was 14.7 years in the surgical group and > 15 years in the medical group (P = NS). In patients with normal LV systolic function and a right coronary artery stenosis > or = 70%, the 15-year cumulative survival rates were also similar in the surgical and medical groups (40% and 48%, respectively). Median survival was 14.3 years in the surgical group and 14.2 years in the medical group (P = NS). The 15-year cumulative survival estimates for all subgroups were affected by convergence of the surgical and medical survival group curves owing to a disproportionate increase in the late surgical group mortality. Overall, 25% of patients in the medical group ultimately underwent CABG surgery. If all medical group patients had survived long enough, about 47% would be estimated to have had surgery by 15 years. CONCLUSIONS This report, which extends follow-up of more than 16 years in CASS Registry patients with LMCD, shows that CABG surgery prolongs life in most clinical and angiographic subgroups. However, median survival was not prolonged by CABG surgery in patients with normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present. These results extend our understanding of the natural history of LMCD and permit a more accurate estimate of long-term surgical and medical group survival.

Prognostic value of angiographic indices of coronary artery disease from the Coronary Artery Surgery Study (CASS).

The Coronary Artery Surgery Study, CASS, enrolled 24,959 patients between August 1975 and June 1979 who were studied angiographically for suspected coronary artery disease. This paper compares the prognostic value for survival without early elective surgery of eight different indices of the extent of coronary artery disease: the number of diseased vessels, two indices using the number of proximal arterial segments diseased, two empirically generated indices from the CASS data, and the published indices of Friesinger, Gensini, and the National Heart and Chest Hospital, London. All had considerable prognostic information. Typically 80% of the prognostic information in one index was also contained in another. Our analysis shows that good prediction from angiographic data results from a combination of left ventricular function and arteriographic extent of disease. Prognosis may reasonably be obtained from three simple indices: the number of vessels diseased, the number of proximal arterial segments diseased, and a left ventricular wall motion score. These three indices account for an estimated 84% of the prognostic information available. 6-yr survival varies between 93 and 16% depending upon the values of these three indices.

The Western Washington Intravenous Streptokinase in Acute Myocardial Infarction Randomized Trial.

Three hundred sixty-eight patients were randomly assigned to receive intravenous streptokinase (IVSK) (n = 191) or standard therapy (n = 177) to determine the efficacy of IVSK in the treatment of acute myocardial infarction. The mean time to treatment was 3.5 hr. At 14 days there were 12 deaths in the treatment group (6.3%) and 17 deaths in the control group (9.6%) (p = .23). Early mortality was related to infarct location. Fourteen day mortality for anterior infarctions was 10.4% for treatment with IVSK and 22.4% for control patients (p = .06) and was similar for IVSK-treated patients with inferior infarctions, 4.0% vs 1.8% (p = .32). For those randomized under 3 hr, 14 day mortality tends to be lower in treated patients, 5.2% vs 11.5% (p = .11). There was significant improvement in long-term survival for patients with anterior infarction; 2 year survival was 81% for IVSK-treated patients and 65% for control patients (p = .05). There was no improvement in survival for patients with inferior myocardial infarction (p = .27). We conclude that patients with anterior myocardial infarction have improved survival when treated within the first 6 hr of symptoms. Patients with inferior infarction do not appear to have improved survival with thrombolytic therapy. Some of this improvement in survival in patients with anterior infarction may be due to a higher frequency of revascularization procedures in the treatment group.