Relationships between left ventricular mass, left ventricular work and coronary artery size in aortic regurgitation--possible mechanism of myocardial ischemia

Clinical implications of exercise-induced regional wall motion abnormalities in significant aortic regurgitation

BACKGROUND

Significant aortic regurgitation (AR) is sometimes accompanied by regional wall motion abnormalities (RWMA) during exercise stress echocardiography. The aim of this study was to estimate the association between RWMA after exercise and in the presence of significant AR in patients with coronary artery disease (CAD) or volume overload and to predict the eventual need for aortic valve replacement (AVR).

METHODS AND RESULTS

We retrospectively reviewed 182 patients with significant AR who underwent exercise echocardiography. In addition, we investigated patients with AR who underwent coronary angiography (CAG) or coronary computed tomography angiography (CCTA) and were diagnosed with CAD. The presence of RWMA after exercise was defined as newly developed RWMA after exercise and included all changes in wall motion. Patients were divided into two groups according to the presence of RWMA after exercise: the RWMA group (n = 42) and non-RWMA group (n = 140). In the RWMA group, 31 patients (73.8%) underwent coronary artery evaluation by CAG or CCTA. Only two patients in the RWMA group were diagnosed with current CAD and underwent percutaneous coronary intervention. Patients with RWMA were older (61.6 ± 10.8 vs 52.0 ± 13.7 years, P < .001), had more severe AR (54.8% vs 32.9%), and underwent AVR more frequently (40.5% vs 14.3%, P = .001) than patients without RWMA. METs (odds ratio [OR], 0.796; P = .019), difference between rest and postexercise left ventricular end-diastolic volume (OR, 0.967; P = .001), and the difference between pre- and postexercise left ventricular end-systolic volume (OR, 1.113; P < .001) were identified as independent factors associated with RWMA after exercise according to multivariable logistic regression analysis. The majority of wall motion changes were seen in the lateral and inferior segments, and the locations of wall motion changes were relatively consistent with the direction of the AR jet. The relationship between RWMA after exercise and time to AVR was investigated by simple linear regression (hazard ratio [HR], 3.402; P < .001). After adjusting for baseline parameters of diastolic blood pressure, left ventricular end-systolic dimension (LVESD), aorta size, deceleration time, and METs, the presence of RWMA after exercise was not predictive of time to AVR (HR, 1.106; P = .81). On the other hand, without forcible entry of RWMA after exercise, LVESD (HR, 1.119; P < .001) and METs (HR, 0.828; P = .006) independently predicted the eventual need for AVR as an outcome.

CONCLUSION

The degree of change in wall motion from rest to exercise in those with significant AR was not correlated with CAD, but was correlated with the severity of volume overload and exercise-induced preload changes, as well as the direction of the AR jet. In addition, RWMA after exercise had no role in predicting the need for AVR.

Aortic regurgitation reduces the accuracy of exercise echocardiography for diagnosis of coronary artery disease

The association of aortic regurgitation with left ventricular size, hypertrophy, and abnormal coronary flow may influence the accuracy of stress testing techniques for the diagnosis of coronary disease. We examined the diagnostic accuracy of treadmill exercise echocardiography to predict coronary artery disease in 76 patients with moderate to severe aortic regurgitation. Rest and poststress images were interpreted by 2 experienced observers, and accuracy was defined by comparison with stenoses >/=50% diameter at coronary angiography. Results were compared with accuracy in a control group of previously published studies in patients without valvular heart disease. After 6 patients were excluded because of a submaximal heart rate response (<85% age-predicted maximal heart rate), 70 patients were included in the final analysis. Patients with aortic regurgitation were of comparable age to the control group and exercised to similar workload. In 16 (23%) patients with significant coronary artery disease and significant aortic regurgitation, the sensitivity of exercise echocardiography was 56% compared with 83% in the control group (P =.03). The specificity in 54 patients with aortic regurgitation but no significant coronary artery disease was 67% compared with 83% in the control group (P =.02). Accuracy was 64% in aortic regurgitation compared with 83% in the control group (P =.02). In patients with aortic regurgitation, accuracy in the left anterior descending artery territory (76%) marginally exceeded that in the posterior (right + circumflex coronary artery) circulation (70%). Thus the presence of significant aortic regurgitation affects the regional wall motion of the left ventricle during exercise and adversely affects the accuracy of exercise echocardiography for the diagnosis of coronary artery disease.