Objectives: This study sought to investigate the specific role of hypertriglyceridemia in the myocardial hyperemic stress with dipyridamole/rest flow ratio (MDR).
Background: Reduced MDR has been reported in hypercholesterolemic patients without evidence of ischemia. However, the specific role of hypertriglyceridemia in MDR has not been studied.
Methods: Fifteen nondiabetic normocholesterolemic hypertriglyceridemic patients and 13 age-matched control subjects were studied. Myocardial blood flow (MBF) during dipyridamole administration and baseline MBF in hypertriglyceridemic patients and control subjects were measured using positron emission tomography and nitrogen-13 ammonia, after which the MDR was calculated.
Results: Baseline MBF (ml/min per 100 g heart weight) in hypertriglyceridemic patients (mean +/- SD 73.6 +/- 24.1) did not differ significantly from that in control subjects (81.6 +/- 37.2). MBF during dipyridamole loading in hypertriglyceridemic patients (198 +/- 106) was significantly reduced compared with that in control subjects (313 +/- 176, p < 0.05), as was the MDR (2.71 +/- 1.07 vs. 3.73 +/- 1.14, respectively, p < 0.05). Spearman rank-order correlation analysis showed a significant relation between plasma triglyceride concentration and MDR (r = -0.466, asymptotic SE 0.157, p = 0.0125); however, no such significant relation was seen between total plasma cholesterol concentration and MDR (r = -0.369, asymptotic SE 0.130, p = 0.059).
Conclusions: Impaired myocardial vasodilation was suggested in hypertriglyceridemic patients without symptoms and signs of ischemia.