196A AJH–APRIL 2000 –VOL. 13, NO. 4, PART 2 ASH XV ABSTRACTS multigate pulsed doppler device (echo-tracking) and the Complior system. SBP/DBP (mmH) FMD (%) NMD (%) carotid diameter (mm) carotid DC (1023/kPa) aortal PWV (m/s) SC CON 132 6 4/76 6 2 6.1 6 1.5* 20.0 6 3.0 6.4 6 1.5 16.4 6 1.9* 12.1 6 1.2* 128 6 3/76 6 3 17.0 6 3.8 21.0 6 2.5 5.9 6 1.2 20.1 6 2.0 10.2 6 0.5 Data are mean6SEM *p,0.01 vs. CON Key Words: Arterial distensibility; endothelial function; pulse wave velocity; systemic scleroderma B026 LOSS OF OSCILLATORY ARTERIAL COMPLIANCE IS DETECTABLE IN YOUNG PATIENTS BY RADIAL ARTERY PULSE CONTOUR ANALYSIS A. Zimmermann, M.D. VanAuker, A. Zakari, J.A. Strom*, and M.A. Weber*. Brookdale University Hospital and Medical Center, and S.U.N.Y. Health Science Center at Brooklyn, New York, USA Background: Arterial compliance (AC) is an index of the capacity of vessels to accommodate changes in blood pressure (BP). It has been postulated that the loss of AC may precede clinical manifestations of hypertension, and that AC may have prognostic value in early identification of patients (pts) at risk. A noninvasive method has been developed to determine large (capacitive) and small (oscillatory) AC from the radial artery (RA) pulse pressure contour by modified Windkessel analysis. In this study we evaluated the ability to detect changes in AC in young pts at risk for hypertension using this method. Methods: RA waveforms were obtained in 54 pts (age 33 6 8 years, range 22– 61) using a tonometric device combined with oscillometric BP measurements. Of these, 23 pts had a family history of hypertension (mean age 5 32 years), and 31 had no known family history (mean age 5 33 years), and 53 pts were normotensive (BP,140/90). Results: Values for large AC and small AC for the entire patient population ranged from 0.670 to 1.94 and 0.025 to 0.147 ml/mm Hg, respectively. Small (oscillatory AC) correlated negatively with age for the entire set (p50.011), and tended to be lower in the patients with family history of hypertension. Large artery compliance was constant with age in this young cohort. An inverse relationship between small AC and diastolic and mean BP was observed. Conclusions: This study suggests that the loss of small (oscillatory) AC may be the earliest detectable change in arterial properties, manifesting itself in people in their 20s Key Words: arterial compliance; Windkessel model; pulse pressure contour B027 A PROSPECTIVE, RANDOMIZED, OPEN-LABEL, BLINDED ENDPOINT, PARALLEL GROUP PILOT STUDY COMPARING THE EFFECTS OF QUINAPRIL AND LOSARTAN ON ARTERIAL STIFFNESS IN PATIENTS WITH MILD TO MODERATE HYPERTENSION (AC/DC) D.H.G. Smith*, J.M. Neutel*, and M.A. Weber*. Memorial Medical Research Clinic, Long Beach, California and the Orange County Research Center, Orange, California Background: Increasing arterial stiffness is an important factor in hypertension. Angiotensin II plays a critical role in hypertension through stimulation of the AT1 receptor and consequent proliferation and hypertrophy of vascular smooth muscle and collagen deposition. Angiotensin II may also contribute to endothelial dysfunction and facilitate lipid deposition in the media of blood vessels—important events in the development of atherosclerosis. Thus, blockade of the renin-angiotensin system (RAS) improves vascular compliance and may reverse atherosclerosis. The ACE inhibitor quinapril (Q) effectively reduces blood pressure (BP) over 24 hours with once-daily dosing. Because it is highly lipophilic, Q penetrates tissue with rapid and profound effects on the RAS. Q has been shown to significantly improve arterial structure and function. In addition to ACE inhibition, the RAS may be blocked at the receptor. Losartan (L) is an AT1 receptor blocker; however, the effects of AT1 receptor blockade on arterial stiffness are unknown. This study is being conducted to determine the effect size and variability of ACE inhibition versus AT1 receptor blockade on arterial stiffness, BP, left ventricular mass and ventricular compliance. Methods: Following a single-blind placebo run-in period, mild to moderately hypertensive adult patients who were not taking antihypertensive medication were randomized to Q (n550) or to L (n552). A forced-titration dosing regimen was begun as follows: Q 20 mg or L 50 mg (2 weeks), Q 40 mg or L 100 mg (2 weeks), Q 80 mg or L 100 mg (8 weeks). Doses were administered once each morning. With dosing complete, patients entered a 72-hour drug-free period. Arterial compliance and 24-hour ambulatory BP were measured following the placebo run-in period and at the end of the 12-week active treatment period. To compare residual drug effects, arterial compliance and 12-hour ambulatory BP were measured at the end of the 72-hour drug-free period. Left ventricular mass and ventricular compliance were evaluated by resting echocardiogram at the end of the placebo run-in period and at the end of the active treatment period. The last study participants have completed treatment and final results are pending analysis. Key Words: ACE inhibitors; hypertension; quinapril; arterial compliance Downloaded from https://academic.oup.com/ajh/article/13/S2/196A/182579 by guest on 06 February 2023 Flow-mediated vasodilation— but not nitroglycerin-induced dilation— of the brachial artery is impaired in patients with systemic scleroderma. Additionally, distensibility of the carotid artery and systemic compliance measured as pulse wave velocity are reduced. Endothelial dysfunction and reduced elastic vessel wall properties may contribute to the increased cardiovascular morbidity and mortality in systemic scleroderma. and 30s before development of elevated BP. Loss of small AC may be accelerated in patients with positive family history.