Gastrointestinal Bleeding Following Left Ventricular Assist Device (LVAD) Implantation: Taking the Pulse of the Problem

Over the course of the last decade, implantation of left ventricular assist devices (LVADs) has become an increasingly popular treatment strategy for patients with advanced heart failure, both as a bridge to heart transplantation and as a ‘‘destination’’ therapy. The first generation of LVADs, based on a pulsatile mechanism, was plagued by poor reliability and high infection and thrombosis rates, leading to the development of smaller and more reliable continuous-flow (CF) LVADs. Following the introduction of CF-LVADs, postimplantation survival rates improved to as high as 50–75 % at 2 years [1]. Not surprisingly, CF-LVAD implantation rates have grown exponentially. With the rapidly expanding use of LVADs, it has become clear that long-term mechanical circulatory support is associated with gastrointestinal (GI) bleeding, now considered one of the more common and recalcitrant longterm complications following LVAD implantation, with a recent meta-analysis reporting the prevalence of GI bleeding near 30 % [2]. While the scope of the problem is well described, the pathogenesis of GI bleeding following LVAD implantation is still uncertain. Most studies report that GI bleeding was far more prevalent in patients supported by CF rather than pulsatile LVADs [3]. Continuous, non-pulsatile flow of blood through the vasculature differs from the normal physiologic state, with significant pathophysiologic implications. An important concept for CF-LVADs is the pulsatility index, a measure of the variation in pulse pressure representing the contribution of the native heart to the cardiac output. Interestingly, most prior studies have reported an inverse relationship between the pulsatility index and the risk of GI bleeding, patients with more pulsatile blood flow less likely to bleed [3, 4]. Although the pathophysiologic link between non-pulsatile flow and an increased propensity to bleed remains incompletely understood, recent investigation has uncovered several potential contributing factors such as the development of an acquired von Willebrand disorder in LVAD patients [5], apparently related to the continuous-flow pattern, similar to patients with aortic stenosis and Heyde’s syndrome [5]. In this issue of Digestive Diseases and Sciences, Jabbar et al. [6] report a single-center, retrospective cohort study describing the incidence and outcomes of GI bleeding in patients during long-term support with CF-LVADs, representing one of the largest published experiences to date. The authors reviewed the records of 112 patients who were followed for a median of 12 months after implantation of the Heart Mate II continuous-flow LVAD. Overall, GI bleeding was reported in 39 % of patients, with the first episode typically occurring within 2 months of implantation. As in most prior reports, GI bleeding was overt in a majority of cases (73 %), and the source of bleeding identified with upper endoscopy in 61 % of patients. Gastro-duodenal erosive disease (erosions or ulcers) was the most frequently observed bleeding lesions, accounting for 38 % of events, followed by angioectasia. Although endoscopic therapy was performed in 39 % of patients, endoscopic therapy did not influence the rate of recurrent GI bleeding. Multivariable analysis identified elevated right heart pressures and post-LVAD ejection fraction as risk factors for GI bleeding. Overall, the findings of this study are in line with comparable other recent reports. The most clinically relevant & Vladimir M. Kushnir vkushnir@wustl.edu