The Coronary Artery Surgery Study (CASS)
Objectives:
The Coronary Artery Surgery Study included two
components, a registry of patients undergoing angiography at participating
sites and a randomized trial component. The primary objective of the registry
was to provide information regarding the effects of coronary artery surgery on
patients with ischemic heart disease within the clinical course of treatment.
The randomized component sought to evaluate the short- and long-term effects of
surgical versus medical interventions in patients with a reduced ejection
fraction and significant coronary artery disease.
Background:
In 1972, the National Heart and Lung Advisory Council
identified the short- and long-term effects of coronary artery surgery and the
patient selection criteria for surgery as topics of high priority. An Ad Hoc
Policy Advisory Board on Coronary Artery Surgery was established to assist the
National Heart, Lung and Blood Institute in developing a program of research
activities. In August 1975, registry patients' entry and randomization began at
the 11 clinical centers and coordinating center. Five additional clinical
centers were added to the trial in 1976.
Subjects:
Patients less than 65 years of age with at least one
clinical manifestation of heart disease (angina pectoris or MI) were eligible
for the randomized trial if the left ventricular ejection fraction was greater
than 35%, had evidence of anatomically significant coronary artery disease, the
coronary artery to be bypassed supplied a viable myocardium, and at least three
weeks had passed since the last myocardial infarction. The CASS registry
consisted of 24,959 patients of which 2,099 were selected for potential
randomization. A total 780 patients were randomized into the two arms of the
trial and the remaining 1,319 patients that were medically eligible, yet
non-randomized were followed for assessment of endpoints along with the
randomized patients. Primary endpoints included death and myocardial
infarction, and secondary endpoints included evaluation of angina and quality
of life. The CASS Limited Access Dataset includes the 780 randomized and 1,319
medically eligible patients and approximately 17 years of follow-up for vital
status. The full registry is not included in the dataset.
Conclusions:
After 8 years of follow-up, survival curves were not
significantly different in the surgical and medical groups. Survival in the
surgical group was significantly better for patients with three vessel disease
and whose ejection fraction was between 35% and 50%. (Circulation, 1985; 72(6
pt 2):V102-9)
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Study Website |
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Study Documentation |
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Data Distribution Agreement |
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