Mechanisms of hypertension after liver transplantation.

Hypertension is the most common cardiovascular complication after liver transplantation. Systemic vasoconstriction underlies transplant hypertension, but the mechanisms contributing to this remain unresolved. Plasma renin, aldosterone, and endothelin (ET)-1 together with augmentation index, a measure of arterial stiffness, were determined before and at intervals of 1, 3, and 6 months after transplant in 32 consecutive patients accepted for liver transplantation. At 3 months, 47% of patients were hypertensive, and at 6 months, 50% of patients were hypertensive. Plasma renin and aldosterone decreased after transplantation but were no different between hypertensive and normotensive patients. Plasma ET-1 levels were elevated pretransplant and decreased at 1 month, but at 6 months, levels were elevated in hypertensive patients but not in normotensive patients (P=0.019). Augmentation index increased after transplant and was greater in the hypertensive patients compared with the normotensive patients (P=0.031). During the first 6 months, the renin-aldosterone system does not play a significant role in posttransplant hypertension. Elevation in plasma ET-1 and increases in arterial stiffness are potential important mechanisms underlying the development of hypertension after liver transplant.