Prognosis with chest pain and normal thallium-201 exercise scintigrams

Abstract

The goal of this study was to determine the prognostic value of a normal exercise thallium-201 (TI-201) scintigram by quantitative criteria in a consecutive series of 349 patients with chest pain. Follow-up was obtained in 345 patients (99%) from 8 to 45 months (mean 34 ± 7). Of these, 60% were men, 26% had typical angina, 21% had chest pain during exercise testing, 29% were unable to achieve 85% or more of maximal predicted heart rate, and in 9% ischemic ST depression (1.0 mm or greater) developed during exercise. At the time of exercise testing, 45% of patients were taking nitrates and 38% were receiving a β-blocking drug. During the follow-up period, there were 5 cardiac deaths (0.51%/year), of which 2 were sudden, 6 patients had a nonfatal myocardial infarction (MI) (0.61%/year). Two of the 5 patients who died and 1 who had MI had angiographically normal coronary arteries. The event rate was significantly higher (p < 0.01) in patients referred for early catheterization (5 of 53; 9%) compared with the rate for those not undergoing early angiography (6 of 298; 2%). However, the event rate was similar in those who underwent catheterization with angiographically normal coronary arteries and in those who had significant coronary artery disease. Patients with chest pain and normal TI-201 scintigrams who had a cardiac event were not predominantly of the mate sex, nor did they have a higher prevalence of typical angina, exercise-induced ST-segment depression or an inability to achieve 85% or more of maximal predicted heart rate normalized for age, compared to those who had no cardiac events. Four other patients (1.1%) subsequently underwent coronary bypass surgery. At follow-up, 34% of patients were taking nitrates, 29% were receiving a β-blocking drug and 54% had persistence of chest pain. In conclusion, patients with chest pain and normal TI-201 exercise scintigrams have a low cardiac death and nonfatal MI rate (1.1%/year), which is comparable to that reported for patients with chest pain and angiographically normal coronary arteries.