Prognosis in patients with an abnormal exercise radionuclide angiogram in the absence of significant coronary artery disease

Twelve-year outcome of patients with an abnormal exercise radionuclide left ventricular angiogram and angiographically insignificant coronary artery disease

This study examines the long-term prognosis of patients with an abnormal exercise radionuclide angiogram in the absence of significant angiographic coronary artery disease (CAD). In general, patients without significant CAD have an excellent prognosis, but the long-term outcome for the subset of patients with an "ischemic" exercise test is not known. In this study, 161 patients with normal coronary arteries or insignificant CAD (< 50% left main and < 70% left anterior descending, left circumflex, or right), resting left ventricular (LV) ejection fraction > or = 0.50, and an abnormal exercise radionuclide angiogram (LV ejection fraction that decreased with exercise or peak exercise LV ejection fraction < 0.60) were followed for a median duration of 11.3 years. The mean delta LV ejection fraction was -0.07, 98 patients (61%) had a decrease in LV ejection fraction of > or = 5 units, and 40 patients (25%) had peak exercise LV ejection fraction < 0.50. During follow-up there were 19 deaths (only 1 of which was cardiac), 7 nonfatal myocardial infarctions, and 9 revascularization procedures. At 12 years, overall survival was 88%, better than the expected survival for the age- and sex-matched general population. Survival free of cardiac death or myocardial infarction was 94% and survival free of any cardiac event including revascularization was 88%. Thus, patients with an abnormal exercise radionuclide angiogram but without significant CAD have an excellent long-term prognosis.

Prognostic value of exercise radionuclide angiography in a population-based cohort of patients with known or suspected coronary artery disease

Five hundred thirty-six residents of Olmsted County, Minnesota, who underwent supine rest and exercise radionuclide angiography because of known or suspected coronary artery disease, were followed for a median of 46 months to determine the prognostic value of exercise radionuclide angiography in a community population who generally did not undergo coronary angiography. There were 71 persons who experienced a new cardiac event (the initial events were cardiac death and nonfatal myocardial infarction in 26 and 45 persons, respectively). A proportional-hazards model identified 4 independent predictors of cardiac events: exercise ejection fraction (p < 0.001), exercise heart rate (p < 0.001), and age (p = 0.04). Four-year infarct-free survival was 98% for the 152 patients with a peak exercise heart rate at or above the median (122 beats/min) and an exercise ejection fraction at or above the median (0.58). In the 150 patients with a peak exercise heart rate < 122 beats/min and an exercise ejection fraction < 0.58, 4-year infarct-free survival was 68%. When this population-based cohort was compared with a referral case series previously reported from our institution, these population-based patients were significantly more likely to be men, to have typical angina, to have higher exercise heart rates and exercise ejection fractions, and were less likely to be receiving beta-receptor antagonist therapy. At each level of exercise ejection fraction, the population-based patients had a slightly but insignificantly greater risk than referral patients for subsequent cardiac events. These population-based data provide strong evidence of the prognostic value of exercise radionuclide angiography in community practice.

Interpreting results of exercise studies after acute myocardial infarction altered by thrombolytic therapy, coronary angioplasty or bypass

Numerous studies have assessed the ability of exercise modalities to predict patient outcome after acute myocardial infarction (AMI). Implicit in the use of these prior data to assess the prognosis of patients currently undergoing exercise studies is the assumption that patients selected for exercise assessment are similar over time and that the data generated in the past are therefore applicable to the current patient populations. This study retrospectively assessed the clinical, exercise, and rest and exercise radionuclide angiographic data in 791 consecutive patients referred for exercise radionuclide angiography within 1 month after AMI during a 5-year period to determine if the clinical and exercise characteristics of patients referred for exercise evaluation after infarction have changed significantly over time. Most parameters examined demonstrated significant increasing trends, including thrombolytic therapy at the time of AMI, revascularization procedure between AMI and exercise assessment, age, beta-blocker usage, Q-wave AMI, inferior infarction, exercise double product, exercise capacity, significant ST-segment depression with exercise, peak ejection fraction, and change in ejection fraction with exercise. These data indicate that the characteristics of patients selected to undergo exercise after AMI in a large referral center have changed significantly over time. If these data are applicable to other referral centers and to other exercise testing modalities, previously published results regarding exercise assessment after AMI will need to be reconfirmed in patients currently selected for testing, since these results may no longer be applicable in this current era of aggressive medical and interventional management.

Prognostic value of radionuclide angiography in medically treated patients with coronary artery disease. A comparison with clinical and catheterization variables

To evaluate the usefulness of multiple measures from rest and exercise radionuclide angiography (RNA) in predicting cardiovascular death and cardiovascular events (death or nonfatal myocardial infarction) and to assess the prognostic usefulness of the RNA relative to clinical and catheterization data, we studied 571 stable patients with symptomatic coronary artery disease who had upright rest/exercise first-pass RNA within 3 months of catheterization and were medically treated. With a median follow-up of 5.4 years, 90 patients have died from cardiovascular causes, and 147 patients have either died or suffered a nonfatal myocardial infarction. Using the Cox regression model and a preselected group of RNA variables, the most important RNA predictor of mortality was exercise ejection fraction (chi 2 = 81, p less than 0.00001). Neither rest ejection fraction nor the change in ejection fraction from rest to exercise contributed additional predictive information. Two other RNA study variables, the change in heart rate from rest to exercise and rest end-diastolic volume index, did contribute additional prognostic information to the exercise ejection fraction (chi 2 = 23, p less than 0.0001). Compared with noninvasive clinical data (history, physical examination, electrocardiogram, and chest radiograph), RNA variables were considerably more predictive of mortality (chi 2 = 71 [clinical variables] versus chi 2 = 104 [RNA]). Remarkably, the strength of the relation of RNA variables with mortality was equivalent to that of the set of catheterization variables previously demonstrated in our large angiographic population to be prognostically important (chi 2 = 104 [RNA] versus chi 2 = 102 [catheterization variables]). The RNA contained 84% of the information provided by clinical and catheterization descriptors combined. Furthermore, the RNA contributed significant additional prognostic information to the clinical and catheterization data (chi 2 = 13.6, p = 0.0035). For cardiovascular events, the relative prognostic usefulness of the RNA was similar, although relations with this outcome were generally weaker. Descriptors from the rest/exercise RNA exhibit a powerful relation with long-term outcomes and can be useful in defining risk, even when clinical and catheterization data are available.

Long-term variability of angina pectoris and electrocardiographic signs of ischemia in syndrome X

The long-term course of angina and the electrocardiographic signs of ischemia were assessed in 13 patients (10 women and 3 men, mean age 49 +/- 6 years) with typical angina pectoris, positive exercise tests, no evidence of coronary spasm and angiographically normal coronary arteries (syndrome X). Clinical and electrocardiographic parameters as well as results of exercise testing and 24-hour electrocardiographic monitoring were assessed at presentation and after a mean follow-up of 6.3 years (range 3 to 9). Mean number of anginal episodes and nitroglycerin consumption per week were similar at presentation and at the last follow-up. Furthermore, no significant difference was noted in heart rate-systolic blood pressure product at 0.1 mV of ST-segment depression (20,363 +/- 5,747 vs 21,649 +/- 5,687 beats/min x mm Hg), at angina (19,223 +/- 5,680 vs 20,126 +/- 6,023 beats/min x mm Hg) and at peak exercise (22,057 +/- 5,669 vs 22,868 +/- 6,122 beats/min x mm Hg). Time to 0.1 mV of ST-segment depression, to angina and to peak exercise was also similar (595 +/- 163 vs 631 +/- 184 s, 524 +/- 156 vs 571 +/- 168 s and 671 +/- 168 vs 718 +/- 186 s, respectively). The number of episodes of ST-segment depression greater than or equal to 0.1 mV during electrocardiographic monitoring was similar at presentation and follow-up (31 vs 25) as was the proportion of painful episodes (39 vs 36%). None of the patients developed major coronary events or cardiomyopathy during follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)