1674 Hypertension is a well recognized complication in heart transplant recipients (HTR) that persists indefinitely following transplantation. Arterial stiffness may play a crucial role in the prevalence (nearly 100%) of post-transplant hypertension. PURPOSE: To noninvasively measure central aortic augmentation index (AIa), an indicator of arterial stiffness, in patients before (PRETX) and after (POSTTX) heart transplantation. METHODS: Prior to and at 2 months after transplantation, a total of 8 HTR (59 yrs of age; n = 7 male; n = 1 female) underwent duplicate measurements of brachial cuff BP by oscillometric sphygmomanometry and radial artery pulse waveform using applanation tonometry. A central aortic BP waveform was synthesized from the measured radial artery pressure waveform using a generalized transfer function and the amplitude and timing of pulse wave reflections were calculated. The same measurements were performed on 8 age- and gender-matched healthy control subjects (CONTR). RESULTS: POSTTX brachial SBP (145 vs 94 mmHg), brachial DBP (90 vs 66 mmHg), and aortic SBP (126 vs 96 mmHg) were significantly greater than PRETX. POSTTX travel time of the aortic reflected pressure wave from the periphery (140 vs 150 msec) was significantly faster. POSTTX travel time of the reflected pressure wave (140 vs 153 msec) was significantly faster and central and peripheral BP and AIa (13 vs 5 %) were significantly greater in HTR compared to healthy CONTR. CONCLUSIONS: Arterial stiffness in patients at 2 months after heart transplantation is greater than in age-matched healthy subjects. Aortic systolic BP augmentation in HTR is due to early return of reflected pressure waves from the lower body and indicates an increase in left ventricular afterload.