Abstract P336: Changes in Arterial Pulse Wave Velocity, Effective Arterial Elastance, and Contractility in Hypertension Induced Cardiovascular Disease in Rats: Independent Prognostic Values

Abstract

Hypertension is an established comorbidity in cardiovascular (CV) disease. Changes in aortic pulse-wave velocity (PWV) have been shown to predict the longitudinal development of hypertension, its underlying vascular alterations, and associated CV risks. However, as the heart and arterial tree are coupled, it has been shown that the successful monitoring of not only CV disease progression, but of its therapies, requires the evaluation of ventriculo-arterial uncoupling and its determinants. This study aimed to establish the relationships between PWV and changes in the estimated effective arterial elastance (Ea) and/or contractility over a wide-range of hypertension-induced CV pathologies in a controlled rodent model/environment. In a large series (n = 96) of anesthetized (pentobarbital) male Sprague-Dawley rats, PWV (carotid-to-femoral), systolic pressures, contractility (preload recruitable stroke work; PRSW), and Ea were evaluated using echocardiography, invasive hemodynamics, and left ventricular (LV) pressure-volume relationships. Data were collected in healthy animals (n = 37) and those with hypertension-induced chronic systolic/diastolic left-ventricular dysfunction (n = 59) (chronic beta-adrenergic stimulation and/or renoprival). A subset of each group, were also studied under common clinical cardio/vasoactive pharmacological interventions. Disease animals had significantly (P < 0.001) higher systolic pressures (141 ± 4 vs 116 ± 4 mmHg), faster PWV (9.0 ± 0.8 vs 5.1 ± 0.5 m/s), and depressed contractility (PRSW: 39 ± 1 vs. 49 ± 1 mmHg*). Both PWV (7.6 ± 0.7 to 4.3 ± 0.4 m/s) and Ea (95 ± 10 to 63 ± 8 mmHg/mL) decreased in response to vascular therapies in the diseased animals; only PWV was reduced in healthy rats. More interestingly, over all conditions, PWV was a poor predictor of both systolic pressures (R 2 =0.00009) and Ea (R 2 = 0.024). but yet was a moderate predictor of PRSW (R 2 =0.23, P < 0.001), suggesting a contractility-dependent velocity of propagation. Taken together, these data suggest that indices of ventriculo-arterial efficacy, cardiac afterload, and peripheral arterial stiffness while all are affected by CV disease, each cannot be used to predict one another, and all provide independent prognostic information in disease.