Ambulatory blood pressure monitoring in renal transplant patients: should it be routinely performed?

Arterial hypertension is common among kidney transplant patients. It increases cardiovascular risk and is a factor for progression of renal failure. Our objective was to perform ambulatory blood pressure monitoring (ABPM) in renal transplant patients with office hypertension.

Patients were divided into 2 groups according to their mean ABPM blood pressures with treatment: well-controlled hypertension (blood pressure [BP] <130/85 mmHg), and poorly controlled hypertension (BP>130/85 mmHg). A "nondipper pattern" was defined as a decrease of <10% or an increase, and a "raiser pattern," in which mean blood pressure was greater during the nocturnal than the diurnal period. "White coat effect" was considered when the mean of 3 BP measurements in the clinic was >140/90 mmHg among well-controlled hypertensive patients as documented by ABPM.

ABPM was performed in 53 patients: 25 (47%) "well-controlled hypertensives" and 28 (53%) "poorly controlled hypertensives." Of the latter, 24 (85%) showed a nondipper or raiser pattern with only 4 revealing dipper patterns. We compared well-controlled with poorly controlled hypertensives. The latter cohort were older (54.4±9.3 vs 45.5±13.8 years; P=.009), received grafts from older donors (56.7±15.0 vs 45.8±17 years; P=.02); had worse renal function measured by serum creatinine (1.7±0.5 vs 1.4±0.4 mg/dL, P=.03) or the Modification of Diet in Renal Disease (MDRD)=4 formula (41.8±14.0 vs 55.4±20.5 mL/min/1.73 m2; P=.009), and displayed more proteinuria (0.30±0.33 vs 0.18±0.10 g/d, P=.08). Nondipper or raiser patients showed a higher mean body mass index (27.1 vs 21.7 kg/m2; P=.04). Among 25 well-controlled patients, 11 presented "white coat phenomenon."

We observed an important "white coat" effect, a large prevalence of uncontrolled nocturnal hypertension, and a small but important incident of "masked hypertension." Factors related to hypertension control were patient age, donor age, renal function, induction use, and proteinuria.