Hypertension after successful renal transplantation.

Thirty-three renal allograft recipients who had high blood pressure (mean arterial pressure more than 105 mm Hg) at least one year after their successful transplant operation were compared with 23 normotensive kidney transplant recipients (mean arterial pressure less than 105 mm Hg) at the General Clinical Research Center. The patients with higher blood pressure had markedly and significantly higher (96 percent) renal vascular resistance and significantly lower (41 percent) renal plasma flow. Responses to salt loading and restriction were suggestive of marked activity of the renin-angiotensin system as were plasma renin activity measurements. Subsequent follow-up has revealed chronic rejection or renal artery stenosis as a probable cause of hypertension for 11 of the 33 patients. The remaining 22 patients had increased renal vascular resistance and decreased renal plasma flow indistinguishable from that in the 11 patients in whom follow-up revealed a cause for their persistent hypertension; however, 21 of these 22 patients have their native kidneys in place.