Large artery function in patients with chronic heart failure. Studies of brachial artery diameter and hemodynamics

Abstract

Background. Although progressive chronic congestive heart failure (CHF) is associated with elevated systemic vascular resistance and increased impedance to ventricular outflow, the contribution of changes in large artery function has not been well documented in humans. Methods and Results. We studied 45 patients with a broad range of clinical severity of CHF and compared noninvasive measurements of brachial artery diameter, flow, and pulse wave velocity with 22 normal controls of similar age. In CHF, mean arterial pressure was lower than in controls (85±1 versus 93±2 mm Hg, p<0.001), as were brachial artery diameter (4.07±0.10 versus 4.53±0.09 mm, p<0.001), flow (40.9±4.1 versus 70.9±11.5 ml·min-1, p<0.02), compliance (1.29±0.12 versus 2.00±0.18 cm4·dyne-1·10-7, p<0.002), and conductance (0.49±0.05 versus 0.76±0.13 units, p=0.06). Limb vascular resistance (40.2±5.0 versus 20.5±3.1 units, p<0.001) and pulse wave velocity (10.6±0.5 versus 9.2±0.4 m·sec-1, p<0.03) were higher than in controls. Brachial artery diameter was progressively lower than in controls as severity of CHF increased (New York Heart Association class II, 4.47±0.23 mm, p=NS; class III, 4.05±0.10 mm, p<0.05; class IV, 3.71±0.28 mm, p<0.05). Similar changes were observed for arterial compliance (class II, 1.76±0.32 cm4·dyne-1·10-7, p=NS; class III, 1.21±0.13 cm4·dyne-1·10-7, p<0.05; class IV, 0.95±0.10 cm4·dyne-1·10-7, p<0.05). While the lower arterial pressure and flow might be expected to passively reduce arterial diameter, this would be associated with a reduced pulse wave velocity and improved arterial compliance, yet the opposite was observed. Differences in large artery function were not likely caused by underlying atherosclerosis alone, because patients with dilated cardiomyopathy and patients with ischemic heart disease of the same sex, age, left ventricular ejection fraction, and exercise treadmill duration had similar changes in large artery function. Conclusions. We conclude that alterations in brachial artery function are present in patients with moderate and severe CHF. The observed reduction in arterial compliance, if present diffusely throughout the arterial tree, could increase left ventricular end-systolic stress directly and through increased velocity of reflected pressure waves from the periphery.