WHICH VARIABLE OF STENOSIS SEVERITY BEST DESCRIBES THE SIGNIFICANCE OF AN ISOLATED LEFT ANTERIOR DESCENDING CORONARY-ARTERY LESION - CORRELATION BETWEEN QUANTITATIVE CORONARY ANGIOGRAPHY, INTRACORONARY DOPPLERMEASUREMENTS AND HIGH-DOSE DIPYRIDAMOLE-ECHOCARDIOGRAPHY

Objectives. This study sought to investigate the angiographic or intra coronary Doppler variables of stenosis severity that best correlate wi th the results of dipyridamole echocardiography. Background. Quantitat ive coronary angiography and intracoronary Doppler flow velocity asses sments are the commonly used techniques for the objective identificati on of significant coronary artery stenosis. Methods. Thirty patients w ith an isolated lesion of the left anterior descending coronary artery (LAB) were studied by means of on-line quantitative coronary arteriog raphy, intracoronary Doppler flow velocity measurements and dipyridamo le echocardiography 6 months after percutaneous transluminal coronary angioplasty. The quantitative arteriographic analyses were performed o n-line; post-stenotic Doppler flow velocities were measured at baselin e and after adenosine infusion, Angiographic and Doppler measurements were compared with the corresponding dipyridamole echocardiographic da ta and analyzed by discriminant analysis. Results. The dipyridamole ec hocardiographic response was positive in 11 patients (37%). The best c utoff values for predicting are abnormal echocardiographic response we re 1) stenotic flow reserve of 2.8 (p = 0.0001); 2) 53% diameter steno sis (p = 0.0001); 3) minimal lumen diameter of 1.35 nnm ip = 0.001); 4 ) coronary flow reserve of 2.0 (p = 0.(0002); and 5) maximal peak velo city df 60 cm/s during hyperemia (p = 0.04). Multivariate analysis ide ntified stenotic flow reserve as the only independent predictor of isc hemia during dipyridamole echocardiography. Conclusions. Stenotic flow reserve is the variable that best describes the functional significan ce of an isolated LAD lesion, and a value of 2.8 is the best predictor of a positive dipyridamole echocardiographic response. Furthermore, a ngiographic variables of stenosis severity relate to echocardiographic test results better than intracoronary Doppler variables. (C) 1998 by the American College of Cardiology.