Faculty Bibliography

Ventricular arrhythmias are common after left ventricular assist device implantation. Malposition of the inflow cannula is one of the few etiologies with a mechanically correctable defect. We present a case of intractable ventricular tachycardia that resolved after surgical repositioning of a HeartMate II inflow cannula. The diagnosis and management of this case demonstrate the utility of imaging studies for detecting inflow cannula malposition and the efficacy of inflow cannula repositioning for treatment.

Cardiogenic shock is a life-threatening condition that occurs in response to reduced cardiac output in the presence of adequate intravascular volume and results in tissue hypoxia. Cardiogenic shock has several underlying aetiologies, with the most common being acute myocardial infarction (AMI). Refractory cardiogenic shock presents as persistent tissue hypoperfusion despite administration of adequate doses of two vasoactive medications and treatment of the underlying aetiology. Investigators of the SHOCK trial reported a long-term mortality benefit of emergency revascularization for shock complicating AMI. Since the publication of the SHOCK trial and subsequent guideline recommendations, the increase in community-based use of percutaneous coronary intervention for this condition has resulted in a significant decline in mortality. Despite these successes in the past 15 years, mortality still remains exceptionally high, particularly in patients with refractory cardiogenic shock. In this Review, we discuss the aetiology and pathophysiology of cardiogenic shock and summarize the data on the available therapeutics and their limitations. Although new mechanical circulatory support devices have been shown to improve haemodynamic variables in patients with shock complicating AMI, they did not improve clinical outcomes and are associated with high costs and complications.

Cardiac surgery with cardiopulmonary bypass may be necessary in patients with pre-existing, continuous-flow, left ventricular assist devices. Heart transplantation or exchange of a malfunctioning left ventricular assist device are the most common scenarios. However, reoperation may also be needed for acquired valvular disease or device malposition. In these cases, operative strategies that enable safe conduct of cardiopulmonary bypass and, if needed, cardioplegic arrest while the left ventricular assist device remains in situ, are essential. Such strategies would avoid unnecessary replacement of working components of the left ventricular assist device and, importantly, avoid damage to them during the period of cardiopulmonary bypass. Adequate anticoagulation, avoidance of regurgitant flow into the device, prevention of blood stagnation in the hardware and careful deairing after periods of pump stoppage are key principles. We present a stepwise algorithm for the management of the HeartMate II device during such cases.

Heart failure continues to be a leading cause of morbidity and mortality throughout the United States. The pathophysiology of heart failure involves activation of complex neurohormonal pathways, many of which mediate not only hypertrophy and fibrosis within ventricular myocardium and interstitium, but also activation of platelets and alteration of vascular endothelium. Platelet activation and vascular endothelial dysfunction may contribute to the observed increased risk of thromboembolic events in patients with chronic heart failure. However, current data from clinical trials do not support routine use of chronic antiplatelet or oral anticoagulation therapy for ambulatory heart failure patients without other indications (atrial fibrillation and/or coronary artery disease) as the risk of bleeding seems to outweigh the potential benefit related to reduction in thromboembolic events. In this review, we consider the potential clinical utility of targeting specific pathophysiological mechanisms of platelet and vascular endothelial activation to guide clinical decision making in heart failure patients.

Patients with continuous flow left ventricular assist devices (CF-LVADs) are at increased risk of bleeding. We reviewed our institutional experience with bleeding in the urinary tract following CF-LVAD implantation andquantified the impact on hospital resource utilization in comparison to bleeding in the gastrointestinal tract, the most commonly reportedmucosal site of bleeding following LVAD implantation. Records were retrospectively reviewed for patients undergoing CF-LVAD implantation at our institution between October 2011 and April 2015. Major adverse events of gross hematuria and gastrointestinal bleeding were identified, and patient demographics and hospital course were reviewed.