Thrombotic and Hemorrhagic Complications Following Left Ventricular Assist Device Placement: An Emphasis on Gastrointestinal Bleeding, Stroke, and Pump Thrombosis

Abstract

The left ventricular assist device (LVAD) is a mechanical circulatory support device that supports the heart failure patient as a bridge to transplant (BTT) or as a destination therapy for those who have other medical comorbidities or complications that disqualify them from meeting transplant criteria. In patients with severe heart failure, LVAD use has extended survival and improved signs and symptoms of cardiac congestion and low cardiac output, such as dyspnea, fatigue, and exercise intolerance. However, these devices are associated with specific hematologic and thrombotic complications. In this manuscript, we review the common hematologic complications of LVADs.

Keywords: device-related thrombus (drt); gastrointestinal bleeding; heart failure; hemorrhagic complications; left ventricular assist device; stroke; thrombotic complications.

Figure 1. The pathophysiological mechanism of LVAD-associated GI bleeds.

This figure highlights the involvement of vWF, increased TNF-α, HFrEF, decreased pulsatile flow, increased aortic stiffness, and severe RV enlargement with TV regurgitation in the development of GI bleeds. Image credits: Joseph Phan and Alex M Parker. GI: gastrointestinal; LVAD: left ventricular assist device; AVM: arteriovenous malformation; TNF-α: tumor necrosis factor-alpha; TF: tissue factor; NT-proBNP: N-terminal-pro hormone brain natriuretic peptide; BUN: blood urea nitrogen; HIF-1a: hypoxia-inducible factor-1a; VEGF: vascular endothelial growth factor. *angiopoietin-2 causes LVAD-associated GI bleeds by disrupting vessel maturation, blocking intracellular connections increasing vascular permeability, and increasing sinusoidal vessel formation.

Figure 2. Diagnostics and medical management of LVAD-associated ischemic strokes.

Follow up with non-contrast CT of the head to rule out immediate hemorrhagic stroke. The following management includes endovascular mechanical thrombectomy as IV thrombolytics are often contraindicated in patients with LVAD as these patients are on anticoagulation and have a recent bleed. If the ischemic infarct is large, provide cerebral edema management by consulting neurosurgery for decompressive hemicraniectomy. Image credits: Joseph Phan and Alex M Parker. LVAD: left ventricular assist device; CT: computerized tomography; INR: international normalized ratio; aPTT: partial thromboplastin time; HTN: hypertension; IV: intravenous *IV thrombolytics are often contraindicated in patients with LVAD implants

Figure 3. Mechanism of action of various anticoagulants, antiplatelets, and thrombolytics used for prevention or treatment of LVAD pump thrombosis.

Anticoagulants include vitamin K antagonists, heparin, direct oral factor Xa inhibitors, and direct oral factor IIa inhibitors. Antiplatelet medications include aspirin, P2Y12 receptor antagonists, and glycoprotein IIb/IIIa inhibitors. Image credits: Joseph Phan and Alex M. Parker. FVII: factor VII; FVIIa: factor VIIa; FIX: factor IX; FIXa = factor IXa; FX: factor X; FXa: factor Xa; FII: factor II; FIIa: factor IIa; FI: factor I; FIa: factor Ia; t-PA: tissue plasminogen activator; vWF: von Willebrand factor; COX-1: cyclooxygenase-1; gp1b: glycoprotein 1b; Gp IIb/IIIa: glycoprotein IIb/IIIa