The diagnosis of coronary artery disease in hypertensive patients with chest pain and complete left bundle branch block: utility of adenosine Tc-99m tetrofosmin SPECT.

Abstract

Hypertensive patients with complete left bundle branch block who experience chest pain present special problems in the radionuclide diagnosis of coronary artery disease (CAD). The aim of this study was to assess the utility of Tc-99m tetrofosmin SPECT for the diagnosis of CAD in 35 hypertensive patients with left bundle branch block hospitalized for chest pain. Images were analyzed semiquantitatively for the presence of both fixed or reversible perfusion defects (method A) or only reversible defects (method B) in the distribution of the left anterior descending artery (LAD) territory. Perfusion defects observed in the territory of any other coronary artery were always considered. Thirty-five patients without infarction underwent adenosine Tc-99m tetrofosmin SPECT, transthoracic echocardiography, and coronary angiography. The mean left ventricular ejection fraction was calculated as 39.9% +/- 11.6%, and the prevalence of CAD was 29%. The sensitivity of SPECT was identical for the two methods at 89%. The specificity increased 19% with method A and 54% with method B. The positive predictive value remained unsatisfactorily low with both methods (27% for method A and 40% for method B), and the negative predictive value improved from 83% with method A to 93% with method B. Only reversible perfusion defects in the LAD territory should be considered significant for CAD, and these patients should undergo coronary angiography. Reversible or fixed perfusion defects in the left circumflex and right coronary artery territories should be evaluated according to other clinical parameters (global left ventricular ejection fraction, extension of perfusion defects). The highly negative predictive value of adenosine SPECT could help in the exclusion of CAD.