Out-patient versus in-hospital ambulatory 24-h blood pressure monitoring in heart transplant recipients

Objective: To study the effect of the environment-in-hospital vs out-patient situation-on blood pressure as measured by ambulatory blood pressure monitoring (ABPM). Patients and methods: Twenty-four hour ABPM was performed sequentially in-hospital and again 9 +/- 3 days later on an out-patient basis, in 30 consecutive heart transplant recipients (27 men, median age 56 years, median time post-transplant 3 years). The same equipment was used on both occasions, without any interim change in medical treatment. Results: Both systolic and diastolic blood pressure were higher in-hospital than as an out-patient: +7+/-7 and +6+/-5 mm Hg respectively for the 24-h average (P < 0.001). Daytime and night-time pressures were affected similarly. Depending on the specific cut-off values used, 37 to 87% of the individual patients were hypertensive in-hospital; 31 to 73% of these had an acceptable blood pressure as an out-patient. The converse was very rare (0 to 73% of the total group). Conclusions: In heart transplant patients blood pressure as assessed from 24-h ABPM is lower in the home environment than during a hospital stay. The post-transplant attenuation of the circadian variation in brood pressure is not influenced by the environment. Checking an unsatisfactory in-hospital ABPM with an outpatient recording may obviate the need for an (intensified) antihypertensive treatment in a substantial number of patients.