Evaluation of carotid artery and aortic intima-media thickness measurements for exclusion of significant coronary atherosclerosis in patients scheduled for heart valve surgery.

OBJECTIVES

We assessed the value of carotid intima-media thickness (CIMT) and thoracic aorta intima-media thickness (AoIMT) in ruling out significant coronary artery disease (CAD) in patients scheduled for heart valve surgery.

BACKGROUND

Evaluation of CAD is needed in most patients undergoing heart valve surgery because of the high surgical morbidity in patients with significant CAD, raising the need for sensitive tests to exclude CAD. Coronary angiography is the reference standard, but this invasive procedure is not cost-effective, because more than two-thirds of these patients do not have significant CAD.

METHODS

In a pilot study, CIMT and AoIMT cutoff values separating low- from high-risk groups were determined in 96 patients by using receiver-operating characteristic curves. Then, a prospective study was conducted in 152 patients to determine the statistical power of these cutoff values used alone or in combination. In both studies, carotid artery ultrasonography and transesophageal echocardiography were performed before coronary angiography and valve surgery.

RESULTS

In the pilot study, CIMT < 0.55 mm and AoIMT < 3 mm were excellent predictors of the absence of CAD. In the prospective study, CIMT and AoIMT criteria were independent predictors of significant CAD in these patients, as assessed by logistic regression analysis. Carotid IMT criterion had 100% sensitivity and 100% negative predictive value. For the AoIMT criterion, sensitivity was 98%, and negative predictive value 99%. Combining the two criteria did not change sensitivity and negative predictive value but increased specificity to 78%.

CONCLUSIONS

Measurements of CIMT and AoIMT may be useful in selecting patients who do not require coronary angiography before heart valve surgery.