ALTERED MYOCARDIAL VASODILATATION IN PATIENTS WITH HYPERTRIGLYCERIDEMIA IN ANATOMICALLY NORMAL CORONARY-ARTERIES

Reduced myocardial vasodilatation (MVD) in hypercholesterolemics witho ut overt coronary stenosis has been reported. However, the status of M VD in hypertriglyceridemics has not yet been clarified. The aim of thi s study was to investigate whether MVD is impaired in patients with hy pertriglyceridemia without overt coronary stenosis, Twenty-three hyper triglyceridemics (10 normocholesterolemic hypertriglyceridemics [HTGs] and lj mixed combined hyperlipidemics [MCHLs]) and 13 age-matched con trols were studied. All patients were proven to have more than one nor mal coronary artery, as diagnosed by coronary angiography, and those s egments that were perfused by anatomically normal coronary arteries we re used in the study. Myocardial blood now (MBF) during dipyridamole D P) loading and baseline MBF were measured by using positron emission t omography and [N-13]]ammonia, after which MVD was calculated. Baseline MBF (mt min(-1) 100 g(-1)) was comparable among HTG (76.0+/-26.1), MC HL (77.0+/-26.1), and controls (80.3+/-38.5). However, MBF during DP l oading was significantly lower in MCHL (159+/-52.5) than in control su bjects (292+/-166, P<.01), while it was comparable in HTG (202+/-104) and controls. MVD was significantly reduced in both HTG (2.70+/-1.09, P<.05) and MCHL (2.07+/-.70, P<.01) compared with controls (3.73+/-1.1 4). MVD in MCHLs tended to be reduced compared with that in HTGs, but the difference was statistically insignificant (P=.08). There was a si gnificant relationship between MVD and both plasma triglycerides (r=-. 47, P<.01) and plasma total cholesterol (r=-.55 P<.01). When controls and HTGs were combined, the relationship between MVD and plasma total triglycerides became more prominent (r=-.55, PV.05), and the significa nt relationship between cholesterol level and MVD disappeared. Multiva riate regression analysis has revealed that the triglyceride level (F= 5.2, P<0.5) was independently related to MVD (r=.69, P<.05). In conclu sion, MVD was reduced in hypertriglyceridemics in anatomically normal coronary arteries. Hypertriglyceridemia is an independent factor for t his abnormality.