Abstract 4245: Cardiovascular Risk and Coronary Flow Reserve in Asymptomatic Individuals
Coronary flow reserve (CFR) may be reduced in patients with mild to moderate stenosis (capable of reducing flow reserve, but to sub-ischemic levels) and in those with microvascular disease (reduced flow reserve and normal epicardial coronary arteries). We determined CFR in 70 asymptomatic individuals as it relates to cardiovascular risk. 70 asymptomatic individuals (48 men and 22 women, age 53.2 (13.6) years) with a normal rest electrocardiogram were studied. All underwent transthoracic Doppler recording of the distal left anterior descending coronary artery flow, at rest as well after adenosine (Hewlett Packard Sonos 7500 device equipped with an S8 transducer). CFR was calculated as the hyperemic to resting coronary diastolic peak velocities ratio. Cardiovascular risk was evaluated with the Framingham Risk Score (FRS). The modified Kolmogorov-Smirnov test suggested that CFR data were approximately normally distributed (D=0.12, p≥0.15). Mean CFR was 2.67(0.73) (minimum= 1.45, maximum=5.19). CFR was poorly related to age (r=−0.20, p=0.11) and FRS (r=−0.18, p=0.13). The unpaired t-test disclosed that CFR was not significantly different between males (n=48) and females [2.67(0.64) vs. 2.66(0.91) respectively, p=0.97], smokers (n=34) and non-smokers [2.84(0.72) vs. 2.50(0.71), p=0.06)], and hyper-cholesterolemics (n=34) and non-hypercholesterolemics (2.53(0.64) vs. 2.80(0.79), p=0.13)]. However, CFR was marginally reduced in hypertensives (n=37) compared with normotensives [2.50(0.73) vs. 2.84(0.70), p=0.05] and significantly reduced in type 2 diabetics (n=13) compared with non-diabetics [(2.13(0.42) vs. 2.79(0.73), p=0.003)]. Multiple regression analysis (dependent variable CFR; independent variables: smoking, hypertension) disclosed that only diabetes was related to CFR (p=0.02). CFR is severely impaired in asymptomatic patients with type 2 diabetes mellitus compared with asymptomatic individuals with the other major conventional cardiovascular risk factors. These findings provide further evidence in support of the notion that although type 2 diabetes mellitus is a metabolic disease of carbohydrate metabolism, it should also be considered a vascular disease.