Phasic Coronary Flow Characteristics in Patients With Constrictive Pericarditis

BACKGROUND: Phasic coronary flow characteristics have been reported in patients with aortic valve disease and hypertrophic cardiomyopathy. The purpose of this study was to assess the differences in coronary flow characteristics between patients with constrictive pericarditis and those with restrictive cardiomyopathy. METHODS AND RESULTS: The study populations consisted of 7 case patients with constrictive pericarditis, 8 with restrictive cardiomyopathy, and 11 control subjects with chest pain and normal coronary arteries. Five minutes after injection of 3 mg of isosorbide dinitrate, phasic coronary flow velocity patterns were analyzed in the proximal segment of the angiographically normal left anterior descending coronary artery at rest using a 0.014-in, 15-MHz Doppler guidewire. Coronary flow reserve was obtained from the ratio of adenosine-induced (0.14 mg x kg(-1) x min(-1) I.V.) hyperemic/baseline time-averaged peak velocity. Although in case patients with constrictive pericarditis and restrictive cardiomyopathy maximal hyperemic time-averaged peak velocity (21+/-8 and 31+/-17 versus 60+/-19 cm/s, respectively; P<.001) and coronary flow reserve (1.3+/-0.4 and 1.6+/-0.6 versus 3.6+/-0.4, respectively, P<.001) were significantly lower than in control subjects, there were no significant differences in these indexes between the two groups of case patients. Velocity half-time of diastolic flow velocity corrected by square root(RR), which indicates deceleration of diastolic flow, in the groups of case patients with constrictive pericarditis and restrictive cardiomyopathy was significantly less than that in control subjects (6.2+/-2.6 and 10.6+/-1.5 versus 16.9+/-2.7, respectively; P<.001); this was also significantly smaller in constrictive pericarditis than restrictive cardiomyopathy (P<.001). This index <9.5 could distinguish constrictive pericarditis from restrictive cardiomyopathy with a sensitivity of 86% and a specificity of 88%. Furthermore, time from the beginning of diastole to diastolic peak velocity corrected by square root(RR) indicating acceleration of diastolic flow velocity in constrictive pericarditis was significantly less than that in restrictive cardiomyopathy and control subjects (2.8+/-1.2 versus 4.8+/-0.8 and 4.4+/-0.6, respectively; P<.001). CONCLUSIONS: Although coronary flow reserve is limited in both constrictive pericarditis and restrictive cardiomyopathy because of restriction of hyperemic response, rapid acceleration and more rapid deceleration of diastolic flow velocity are more characteristic in constrictive pericarditis than in restrictive cardiomyopathy.