Relation between Coronary Blood Flow and Left Ventricular Mass in Hypertension. Noninvasive Quantification of Coronary Blood Flow by Thallium-201 Myocardial Scintigraphy.

This study was conducted to quantify coronary blood flow (CBF) noninvasively according to the fractionation principle and to elucidate the relation between CBF and left ventricular hypertrophy. CBF/cardiac output (CO), estimated on the basis of the ratio of myocardial uptake/total injected dose of thallium-201 (% cardiac uptake), was determined in 14 control subjects and 40 patients with essential hypertension. CBF and CBF per 100 g of myocardium (unit CBF) were calculated according to the following formulas: CBF= % cardiac uptake x CO, and unit CBF = (CBF/LVM) X 100, where CO and left ventricular mass (LVM) are echocardiographically determined. There was good reproducibility of % cardiac uptake (r = 0.983, p < 0.0001). Percent cardiac uptake was greater in hypertensive patients (4.65+/-1.44%) than in control subjects (3.64+/-0.64%), and there was a positive correlation between % cardiac uptake and LVM. CBF (ml/min) was greater in hypertensive patients (240.7+/-80.5) than in control subjects (194.9+/-36.9), but unit CBF (ml/min/100 g) was less in hypertensive patients (102.2+/-26.7) than in control subjects (150.3+/-30.5). Multiple regression analyses showed that LVM was the most potent independent predictor of resting CBF in hypertension. Our results indicate that CBF, determined by thallium-201 myocardial scintigraphy, increases parallel to the increase in LVM, but unit CBF decreases even in the resting condition in patients with essential hypertension.