Elevated 24-hour blood pressure in peritoneal dialysis patients with ultrafiltration failure

Many patients treated with peritoneal dialysis (PD) are overhydrated. We investigated whether hypertension in PD patients is related to ultrafiltration-failure-induced fluid retention. Twenty-four-hour blood pressure measurements were performed in 10 normotensive and 9 hypertensive PD patients, aged 20 to 77 years, and treated with PD for 2 to 125 months. Antihypertensive medication had been discontinued for 3 weeks. Twenty-four-hour blood pressure was monitored with a Spacelabs 90207. Mean 24-hour systolic, mean, and diastolic pressure were calculated, together with the nighttime (23:00-07:00)/daytime (07:00-23:00) ratio. Ultrafiltration was determined separately during a standardized 4-hour peritoneal permeability analysis (SPA) with 1.36% glucose. Based on the SPA, patients were divided into a group with negative net ultrafiltration (NUF) and a group with positive net ultrafiltration (PUF). In 8 patients with NUF, systolic, mean, and diastolic pressures were 142 +/- 16 mmHg, 110 +/- 14 mmHg, and 95 +/- 13 mmHg, compared to 135 +/- 22 (ns), 99 +/- 14 (ns), and 81 +/- 11 (P < 0.05) in 11 patients with PUF. Net ultrafiltration during the test dwell correlated negatively with diastolic blood pressure (r = -0.53, P < 0.05). Diurnal blood pressure variations were not related to ultrafiltration capacity. In conclusion, hypertension in PD patients may in part be explained by fluid retention caused by impaired ultrafiltration.