Decreased coronary reserve in primary scleroderma myocardial disease

Abstract
We assessed coronary reserve, by measuring the increase in coronary sinus blood flow (CSBF) after intravenous administration of dipyridamole (0.14 mg/kg/minute for 4 minutes), in 7 patients with primary scleroderma myocardial disease (PSMD) and in 7 control subjects. Coronary reserve was greatly impaired in PSMD: before administration of dipyridamole, CSBF was similar in patients with PSMD (89 ± 32 ml/minute/100 gm, mean ± SD) and in controls (100 ± 15 ml/minute/100 gm); after dipyridamole infusion, CSBF was significantly lower in patients with PSMD (191 ± 45 ml/minute/100 gm) than in controls (399 ± 58 ml/minute/100 gm) (P < 0.01). Six of the 7 patients with PSMD had angiographically normal epicardial coronary arteries and normal left ventricular function. Decreased coronary reserve may be an important contributor to the pathogenesis of primary scleroderma myocardial disease.