Outflow graft obstruction after left ventricular assist device implantation: a retrospective, single‐centre case series

Abstract

Aims Outflow graft obstruction is a poorly described complication following left ventricular assist device (LVAD) surgery. We sought to define the incidence of LVAD outflow graft obstruction and assess clinical outcomes with a percutaneous treatment strategy. Methods and results From January 2012 to October 2020, 322 patients with LVAD were managed at our institution. Patients with LVAD outflow graft obstruction were identified by cardiac computed tomography with angiography and invasive haemodynamic assessment and were subsequently treated with percutaneous intervention. Poisson regression was used to analyse time-dependent differences in the incidence of LVAD outflow graft obstruction. Kaplan-Meier analysis was used to estimate survival. Twenty patients (6.2%) developed haemodynamically significant LVAD outflow graft obstruction at a rate of 0.03 events per patient-year. Outflow graft obstruction presented a median of 33 (26-49) months after surgery. Patients presented with low estimated LVAD pump flow (95%), heart failure (90%), or both (85%), and 59% developed cardiogenic shock prior to intervention. The most common aetiology identified by cardiac computed tomography with angiography was external compression of the outflow graft (78%). On presentation, the median peak gradient in the outflow graft was 78 (64-100) mmHg. Outflow graft stenting was 100% successful with no in-hospital mortality, and it reduced the peak outflow graft gradient to 10 (2-17) mmHg (P < 0.001). Outflow graft stenting was durable with two patients (10%) requiring a repeat procedure over a median follow-up of 13 (7-20) months and did not impact survival. Conclusions Left ventricular assist device outflow graft obstruction is a relatively common and underappreciated cause of recurrent heart failure and LVAD dysfunction. Outflow graft stenting can be achieved with low morbidity and provides a long-term solution to this complication.

Cerebral protection during percutaneous intervention for left ventricular assist device outflow graft obstruction

“…Unfortunately, the rate of periprocedural stroke during outflow graft stenting remains unknow. However, in a previous case series of LVAD patients who underwent outflow graft stenting without cerebral protection, the rate of periprocedural embolic stroke was 5% 14 …”

Recurrent Heart Failure after Left Ventricular Assist Device Placement

“…Abnormal inflow cannula position is associated with increased left heart filling pressures and a > 2-fold increased risk of recurrent HF [82]. By contrast, outflow cannula obstruction is more common and likely underappreciated; dozens of case reports and case series exist, with an event rate of 0.03 EPPY in the largest study [83]. The commonest pathology seems to be external compression from buildup of an acellular fibrinous material between the outflow graft and the protective GoreTex wrap that is frequently placed around the graft at implant.…”

“…The commonest pathology seems to be external compression from buildup of an acellular fibrinous material between the outflow graft and the protective GoreTex wrap that is frequently placed around the graft at implant. Notably, ~80% of patients with clinically significant outflow cannula obstruction will have recurrent HF [83].…”

“…Although rare, malalignment of the inflow cannula may require surgical correction. Outflow cannula obstruction is predominantly caused by external compression of the outflow graft or stenosis of the aortic anastomosis [83]. While surgical correction is an option, the safety and long-term durability of outflow graft stenting has recently been confirmed and can be performed with very low morbidity [83].…”

Durable Left Ventricular Assist Device Outflow Graft Obstructions: Clinical Characteristics and Outcomes

“…While the rate of pump thromboses decreased, cases of outflow graft obstructions due to a specific twisting of the graft prompted an FDA recall [ 4 ]. In regard to outflow graft pathology, other kinks, intramural outflow graft thromboses, and external compressions have been reported in case reports and small case series [ 3 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Although the prevalence of this entity is likely higher than described, given the small number of published cases, there are limited recommendations on approaches to diagnosis and treatment.…”