Peripheral venous congestion causes time- and dose-dependent release of endothelin-1 in humans.

Endothelin-1 (ET-1) is a pivotal mediator of vasoconstriction and inflammation in congestive states such as heart failure (HF) and chronic kidney disease (CKD). Whether peripheral venous congestion (VC) increases plasma ET-1 at pressures commonly seen in HF and CKD patients is unknown. We seek to characterize whether peripheral VC promotes time- and dose-dependent increases in plasma ET-1 and whether these changes are sustained after decongestion. We used a randomized, cross-over design in 20 healthy subjects (age 30 ± 7 years). To experimentally model VC, venous pressure was increased to either 15 or 30 mmHg (randomized at first visit) above baseline by inflating a cuff around the subject's dominant arm; the nondominant arm served as a noncongested control. We measured plasma ET-1 at baseline, after 20, 60 and 120 min of VC, and finally at 180 min (60 min after cuff release and decongestion). Plasma ET-1 progressively and significantly increased over 120 min in the congested arm relative to the control arm and to baseline values. This effect was dose-dependent: ET-1 increased by 45% and 100% at VC doses of 15 and 30 mmHg, respectively (P < 0.05), and declined after 60 min of decongestion though remaining significantly elevated compared to baseline. In summary, peripheral VC causes time- and dose-dependent increases in plasma ET-1. Of note, the lower dose of 15 mmHg (more clinically relevant to HF and CKD patients) was sufficient to raise ET-1. These findings support the potentially contributory, not merely consequential, role of VC in the pathophysiology of HF and CKD.

Hypertension: an unstudied potential risk factor for adverse outcomes during continuous flow ventricular assist device support.

In end-stage heart failure, left ventricular assist devices (LVADs) represent an exciting new frontier in which post-device implantation survival approaches that of heart transplant. However, expansion of this technology is still limited by complications that impact morbidity and mortality. Thus, it is essential to identify and optimize modifiable predictors of poor outcomes. One such predictor may be hypertension (HTN). Not only may chronic HTN as a traditional cardiovascular risk factor be present during long-term LVAD support, but HTN may also contribute to device malfunction or device-associated complications. Although current guidelines identify blood pressure (BP) control as important to outpatient continuous flow (CF) LVAD management, there is no evidence base to support these guidelines. Indeed, our comprehensive literature search did not identify any studies that evaluated post-device implantation HTN as a potential predictor of adverse CF-LVAD outcomes. HTN among CF-LVAD patients is likely a relatively unstudied factor because of difficulties using standard noninvasive techniques to measure BP in the setting of reduced pulsatile flow. Fortunately, recent research has elucidated the meaning of Doppler BP measurements and validated a slow-cuff deflation system for BP measurements in the setting of CF-LVAD support. Therefore, CF-LVAD researchers and clinicians may (1) consider potential mechanisms relating HTN to poor outcomes, (2) realize that HTN management is a stated goal despite scarce evidence, and (3) utilize the new reliable and valid methods for outpatient BP measurement that make research and management possible. It is critical and now feasible that research on HTN in the CF-LVAD patient population move forward.