Prognostic Implication of Stress Echocardiography in 6214 Hypertensive and 5328 Normotensive Patients
How does the prognostic value of stress echocardiography (SE) compare in patients with and without hypertension (htn+, htn-)?
SE was performed in 11,542 patients, of whom 6,214 were hypertensive and 5,328 were normotensive. Exercise echocardiography was performed in 686, dobutamine stress in 2,524, and dipyridamole stress in 8,332 patients for evaluation of known (n = 4,563) or suspected (n = 6,979) coronary artery disease (CAD). Patients were followed for a median of 25 months for endpoints of death or nonfatal myocardial infarction (MI). The 2,764 patients who underwent revascularization were sensored for analysis.
Htn+ patients were older (65 ± 10 years) compared to htn- (61 ± 12) patients. Prior MI was present in 35% of htn- and 31% of htn+ patients; diabetes was present in 24% of htn+ versus 14% in htn- patients; elevated cholesterol was seen in 51% of htn+ versus 40% of htn- patients, and 32% of htn+ versus 44% of htn- patients were active smokers (all comparisons, p < 0.0001). A resting wall motion abnormality (RWMA) was seen in 47% of htn- and 38% of htn+ patients. SE was normal in 50% of htn+ versus 42% of htn- patients; an ischemic abnormality was noted in 26% of htn+ versus 30% of htn- patients, and an infarct pattern in 24% of htn+ versus 28% of htn- patients (all p < 0.0001). On follow-up, there were a total of 1,587 events (14%) including 924 deaths and 663 MIs. In patients with known CAD, the annual event rate was 7.0% in htn+ and 5.7% in htn- patients (p = 0.02), with corresponding event rates of 3.7% and 2.4% in patients with suspected CAD (p < 0.0001). On multivariable analysis, age, male gender, diabetes, RWMA, and ischemia on SE were independent predictors of events in both hypertensive and normotensive patients. For the cohort of patients on antianginal therapy, annual event rates in htn+ and htn- patients were 10.6% and 9% for those with ischemia and RWMA, 7.7% and 6.5% in those with ischemia only; 4.6% and 5.9% in those with an infarct pattern and 3.6% and 3.1% for normal studies (all p = NS). For patients not on active antianginal therapy, event rates for htn+ and htn- were 11.4% and 6.4% for ischemia with RWMA and 9.0% and 4.3% for ischemia without RWMA; 5.4% and 4.7% for an infarct pattern and 2.0% and 1.5% for normal SE (p = NS for infarct, p ≤ 0.009 for other comparisons).
The authors concluded that SE provides valuable prognostic information in hypertensive and normotensive patients.
SE has been established as an accurate means of identifying obstructive CAD, and its prognostic utility has been clearly demonstrated in the general population as well as subsets such as diabetics, the elderly, females, and those undergoing major vascular procedures. This large study nicely demonstrates the equivalent prognostic information available in hypertensive and nonhypertensive patients. While providing prognostic information in both subsets, the value of a negative study was somewhat greater in the nonhypertensive population. This study also demonstrates a higher event rate in patients >65 years old, and a somewhat higher event rate in the hypertensive versus nonhypertensive population. Of note, the majority of patients in the study underwent SE using dipyridamole (72%), an agent not typically used for SE in the United States. The degree to which the choice of this particular agent impacts the results is purely conjectural, but will need to be taken into account when comparing these results to those of other studies using exercise or a stressor such as dobutamine.
Keywords: Coronary Artery Disease, Myocardial Infarction, Follow-Up Studies, Echocardiography, Stress, Hypercholesterolemia, Hypertension, Diabetes Mellitus, United States
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