Relation between exercise-induced left ventricular wall motion abnormalities and coronary artery disease in hypertensive patients: effects of blood pressure normalization

Advantages of exercise echocardiography in comparison to dobutamine echocardiography in the diagnosis of coronary artery disease in hypertensive subjects

OBJECTIVE

The aim of the study was to compare the efficacy and safety of two stress echocardiography methods, exercise and dobutamine, in the diagnosis of coronary artery disease in hypertensive patients with angina.

PATIENTS AND METHODS

A total of 197 treated hypertensive patients, age 53 +/- 9 years (65 women) with no history of myocardial infarction referred for coronary angiography were prospectively investigated with exercise electrocardiography (ECG), exercise and dobutamine echocardiography.

RESULTS

Sensitivity of the exercise ECG, exercise echocardiography and dobutamine echocardiography did not differ (77%, 82% and 75%). Negative predictive value of exercise ECG was significantly lower than exercise echocardiography (64% vs 79%, P < 0.01). Specificity and positive predictive value of exercise ECG were markedly lower than exercise and dobutamine echocardiography (57%, 96%, 98% and 72%, 97%, 98%, P < 0.0001 for both stress echocardiography vs ECG). Specificity and sensitivity of diagnostic methods were not influenced by the presence of echocardiographic left ventricular hypertrophy. Dobutamine infusion in comparison to exercise was more often associated with substantial arterial blood pressure rise or fall (7% vs 2%, P < 0.05) and with simple ventricular ectopy (15,7% vs 6,1%, P < 0.05).

CONCLUSIONS

In hypertensive patients with the symptoms of angina, both stress echo methods are significantly more specific than the exercise ECG test. Maximal exercise is associated with less frequent side effects than infusion of dobutamine, so exercise echocardiography may be preferred in the diagnosis of angina in hypertensive patients.

Exercise echocardiography versus exercise electrocardiography in the diagnosis of coronary artery disease in hypertension

In hypertension, coronary artery disease (CAD) can be overestimated by stress electrocardiography (ECG) and scintigraphy due to frequent false-positive results. Exercise tests are also limited by an excessive blood pressure increase, and pharmacologic pressure normalization decreases the accuracy of the test. The aim of this study was to assess the accuracy of exercise echocardiography as an alternative test for CAD detection in hypertension, both before and after adequate blood pressure control. We studied 59 hypertensive and 59 normotensive patients undergoing coronary angiography for chest pain. Upright bicycle exercise ECG and echocardiographic tests were performed in each group in the absence of therapy; in hypertensives, the tests were repeated a day apart after blood pressure normalization with sublingual nifedipine. Significant CAD (lumen narrowing >50%) was detected in 22 hypertensive and 41 normotensive patients. In the two groups, sensitivity, specificity, and diagnostic accuracy of exercise echocardiography performed before treatment were not statistically different (95%, 94%, 94% in hypertensives and 82%, 77%, 83% in normotensives, respectively), but were significantly higher than for the exercise ECG test (68%, 70%, and 69%, respectively). After blood pressure lowering, exercise echocardiography sensitivity slightly decreased (91%), whereas specificity (100%) and diagnostic accuracy (96%) did not vary; on the contrary, exercise ECG sensitivity decreased to 45%. Therefore, according to our data, exercise echocardiography can be an accurate test and more reliable than exercise ECG to detect CAD in normotensives as well as in hypertensives. Normalization of blood pressure with nifedipine does not affect its accuracy, but markedly reduces the sensitivity of exercise ECG.