Impaired Myocardial Vasodilation During Hyperemic Stress With Dipyridamole in Hypertriglyceridemi

Objectives. This study sought to investigate the specific role of hypertriglyceridemi 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 hypertriglyceridemi 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 significant relation between plasm triglyceride concentration and MDR (r = −0.466, asymptotic SE 0.157, p = 0.0125); however, no such significant relation was seen between total plasm 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.