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), ages30–46 years, with echocardiographically documented mitralvalve prolapse and clinical suspicion of coronary artery disease,based on a history of chest pain (five patients), angina-likepain (three patients), a positive exercise stress electrocardiogram(12 patients) and a focally positive thallium-201 stress perfusionscan (three patients), who were referred for cardiac catheterizationand found to have normal coronary arteries. Ten patients withoutevidence of heart disease served as controls. In all mitralvalve prolapse patients, coronary flow velocity reserve wasdetermined successively in the left anterior descending, leftcircumflex and right coronary arteries as the ratio of the maximun(after intracoronary papaverine) to the resting mean coronaryflow velocity. Coronary flow reserve values were fairly similarin the mitral valve prolapse and control patients; all 12 mitralvalve prolapse patients had normal coronary flow reserve (3.5)in all three coronary arteries with no significant differencesamong the arteries tested Mean values ± 1 standard deviationof the coronary flow reserve (mitral valve prolapse vs controlpatients) were 4.7 ± 0.5 vs 4.6 ± 0.6 for theleft anterior descending, 4.6 ± 0.4 vs 4.6 ± 0.3for the left circumflex and 4. ± 0.4 vs 4.4 ±0.5 for the right coronary artery (all P=non-significant). Thesubsets of mitral valve prolapse patients with different clinical‘ischaemic’ manifestations were similar in termsof the calculated coronary flow reserve in all three major epicardialcoronary arteries. In conclusion, this study demonstrated that an inadequate regionalcoronary flow reserve does not account for the clinical manifestationsof myocardial ischaemia and positive exercise tests in patientswith mitral valve prolapse and normal coronary arteries.