AMBULATORY BLOOD-PRESSURE IN CHRONIC RENA L-INSUFFICIENCY, ON HEMODIALYSIS AND AFTER RENAL-TRANSPLANTATION

Ambulatory blood pressure monitoring does not only provide more precis e blood pressure measurement because of avoiding >>white coat<< hypert ension, but it also informs about the circadian rhythm of blood pressu re. Patients with chronic renal insufficiency, on hemodialysis therapy and after renal transplantation have on average an abnormal below 10% decline of nocturnal arterial pressure in comparison to daytime value s. The loss of a nocturnal recovery phase with lower pressure burden c auses an increased risk of cardiovascular disease. In diabetic nephrop athy already with the occurrence of microalbuminuria a reduced night-t o-daytime-blood pressure variation can be shown, which is further redu ced with progressing nephropathy and in chronic renal insufficiency. A utonomic neuropathy also reduces the nocturnal decline of blood pressu re and in advanced cases causes an inverse diurnal rhythm with paradox ically increased blood pressure at night time above daytime values, co rresponding to a nocturnal preponderance of sympathetic over vagal ner vous activity. Such an inverse rhythm was found in 50% of type II diab etic patients with chronic renal insufficiency and on hemodialysis. Wi th hemodialysis therapy ambulatory blood pressure measurement over 48 hours shows on average a near-constant blood pressure during dialysis sessions and in the interdialytic interval, which is best estimated by postdialysis blood pressure measurement. A proportion of patients has volume-dependent hypertension with a postdialytic decline of blood pr essure and a renewed rise during the predialytic day. Using the normat ive criterion of a mean daytime-blood pressure value below 135/85 mmHg , about half of the dialysis population can be found to be hypertensiv e in recent studies. Complete lack of hypertension proven in ambulator y blood pressure measurement in a large cohort of dialysis patients in Tassin/France with a regime of three times 8-hour dialysis sessions p er week is impressive, because these patients under long dialysis sess ions show a superior survival above international rates. The majority of patients after renal transplantation is hypertensive, which could n ot be recognized by means of office blood pressure measurement in 45% of our hypertensive patients.