Amplitude and timing of central aortic pressure wave reflections in heart transplant recipients

BACKGROUND: Hypertension (HTN) assessed by sphygmomanometer is a common finding in heart transplant recipients (HTR); however, little is known about the contribution of arterial wave reflection to central aortic pressure in these patients. The aim of this study was to measure the central aortic pressure wave in HTR on antihypertensive therapy and determine the effects of amplitude and timing of wave reflection on the various components of the wave. METHODS: A total of 53 stable adult HTR on antihypertensive medication underwent brachial artery blood pressure ([BP]; by sphygmomanometry) and central aortic pressure (by noninvasive radial artery applanation tonometry and use of a generalized transfer function) measurements at rest. Central aortic augmentation index (Ala), an indicator of arterial stiffness, was calculated from the aortic pressure waveform. Patients were divided into three groups (A, B, and C) based on the amplitude of AIa. RESULTS: Mean brachial BP was 136 +/- 15/84 +/- 9.4 mm Hg. Group A patients (n = 25) had a higher AIa (average 21% +/- 7.6%) than group B (n = 18, AIa = 6.5% +/- 3.0%, P < .001) or group C (n = 10, AIa = -8.7% +/- 8.1%, P < .001) patients. The amplitude of AIa was inversely related to the travel time (delta(t)p/2) of the reflected pressure wave from the periphery to the heart (r = -0.78, P < .001). Despite this clear stratification of patients by aortic pulse wave analysis, standard cuff pressure was similar among the groups. CONCLUSIONS: Noninvasive analysis of the central aortic PRESSURE wave identified a subgroup of hypertensive HTR with increased arterial stiffness, increased propagation of the reflected wave, and augmented aortic systolic and pulse pressure not identified with the sphygmomanometer.