Preinfarctional (Unstable) Angina—A Prospective Study— Ten Year Follow-Up

One hundred and forty patients with preinfarctional (unstable) angina were followed for ten years for the purpose of determining the natural history and the prognostic significance of electrocardiographic findings. The cumulative survival rate for the 140 patients was as follows: 12 months: 82%; 24 months: 75%; 36 months: 69%; 60 months: 61%; and 120 months: 48%. Twentyone percent (29 of 140) of the patients developed an acute myocardial infarction within eight months of the onset of the diagnosis of preinfarctional angina with an associated mortality of 41.4% (12 of 29). A combination of high-risk factors in a patient, e.g., frequent angina in the hospital, prior stable angina, and ischemic ST change during pain, identified his as a high-risk case. The high-risk subgroup (54) had a cumulative survival rate as follows: 12 months: 57%; 24 months: 47%; 36 months: 37%; 60 months: 27%; and 120 months: 19%. Thirty-five percent (19 of 54 patients) of this subgroup developed a myocardial infarction within three months of the onset of preinfarctional angina with an associated mortality rate of 63% (12 of 19 patients). At the first year follow-up, 18% (25 of 140) of the patients died; 74% (104 of 140) had less angina; and 8% (11 of 140) did not show a change in their anginal pattern. These data can be used as a basis for a controlled trial of surgical treatment for preinfarctional angina.