CAPD PATIENTS EXHIBIT A NOCTURNAL FALL IN BLOOD-PRESSURE - A SINGLE-CENTER STUDY

Background: In 29 CAPD (continuous ambulatory peritoneal dialysis) pat ients the height and diurnal variation of the blood pressure (BP) and heart-rate (HR) were analyzed by means of 24-hour ambulatory blood pre ssure monitoring (ABPM).Methods: Normal diurnal variation was defined as a fall of 10% or more during nighttime (NT) compared with daytime ( DT) BP or HR (DT = 10.00 a.m.-9.00 p.m., NT = midnight-06.00 a.m.). To evaluate high BP in the course of time we used the concept of ''whole -day BP load'', defined as the percentage of BP readings above 140/90 mmHg during a 24-h period. A ''hypertensive BP load'' was defined as a systolic BP (SEP) load of more than 50% and/or a diastolic BP (DBP) l oad in excess of 40%. In addition to analysis of the circadian rhythm of BP and HR and the prevalence of a hypertensive BP load in CAPD pati ents, the influence of various factors such as gender, creatinine clea rance, recombinant human erythropoietin, antihypertensive medication, haematocrit, whole-day BP load, and the nightly dialysis glucose conce ntration on the diurnal variation of BP and HR were studied. Results: Based on the 95% confidence intervals for the proportional nocturnal d ecrease, normal diurnal variation of BP and HR was present in most CAP D patients. No correlation could be demonstrated between a blunted cir cadian rhythm and the variables mentioned above. However, when other t ime-period definitions (DT = 6.00 a.m.-11.00 p.m., NT = 11.00-6.00 and DT = 8.00 a.m.-8.00 p.m., NT = 8.00 p.m.-8.00 a.m.) were applied to t he data, considerably fewer patients displayed normal diurnal variatio n. Whereas all patients showed normal home BP readings, ABPM of 21 out of 29 patients displayed a hypertensive BP load. Conclusion: The majo rity of our CAPD patients exhibited normal diurnal variation of SEP an d DBP depending, however, on the definitions of DT and NT used. The ab sence of a normal circadian rhythm could not be explained by any of th e variables analyzed. Surprisingly, uncontrolled hypertension, as defi ned by a hypertensive BP load, was found in 72% of the patients.