NORMAL CORONARY FLOW RESERVE IN PATIENTS WITH MITRAL-VALVE PROLAPSE, A POSITIVE EXERCISE TEST AND NORMAL CORONARY-ARTERIES

We studied 12 patients (eight females and four males), ages 30-46 year s, with echocardiographically documented mitral valve prolapse and cli nical suspicion of coronary artery disease, based on a history of ches t pain (five patients), angina-like pain (three patients), a positive exercise stress electrocardiogram (12 patients) and a focally positive thallium-201 stress perfusion scan (three patients), who were referre d for cardiac catheterization and found to have normal coronary arteri es. Ten patients without evidence of heart disease served as controls. In all mitral valve prolapse patients, coronary flow velocity reserve was determined successively in the left anterior descending, left cir cumflex and right coronary arteries as the ratio of the maximum (after intracoronary papaverine) to the resting mean coronary flow velocity. Coronary flow reserve valued were fairly similar in the mitral valve prolapse and control patients; all 12 mitral valve prolapse patients h ad normal coronary flow reserve (greater than or equal to 3.5) in all three coronary arteries with no significant differences among the arte ries tested. Mean values +/- 1 standard deviation of the coronary flow reserve (mitral valve prolapse vs control patients) were 4.7 +/- 0.5 vs 4.6 +/- 0.6 for the left anterior descending, 4.6 +/- 0.4 vs 4.6 +/ - 0.3 for the left circumflex and 4.5 +/- 0.4 vs 4.4 +/- 0.5 for the r ight coronary artery (all P = non-significant). The subsets of mitral valve prolapse patients with different clinical 'ischaemic' manifestat ions were similar in terms of the calculated coronary flow reserve in all three major epicardial coronary arteries. In conclusion, this stud y demonstrated that an inadequate regional coronary flow reserve does not account for the clinical manifestations of myocardial ischaemia an d positive exercise tests in patients with mitral valve prolapse and n ormal coronary arteries.