Left Ventricular Assist Device Outflow Graft Obstruction: A Case Series

Abstract

Dysfunction of different components within continuous-flow (CF) left ventricular assist device (LVAD) systems may cause adverse cardiovascular and end-organ sequelae. Outflow graft obstruction is a recognized type of LVAD component dysfunction. Ten patients were admitted and treated for LVAD outflow graft obstruction. Two of these patients subsequently developed recurrent outflow graft obstruction requiring reintervention; however, each reoccurrence was at a different site than the original obstruction. Thus, a total of 12 cases of obstruction were analyzed. The most common reasons for hospital admission were low flow LVAD alarms or decompensated heart failure. Presentation with outflow graft obstruction occurred an average of 3.0 years after LVAD implantation. Patients underwent echocardiographic evaluation at the time of admission. Left ventricular assist device component dysfunction was suspected based on echocardiographic findings, and follow-up contrast studies were used to establish the specific diagnosis of outflow graft stenosis. The majority of stenotic lesions (10/12) were treated percutaneously with balloon angioplasty and stenting with balloon-expandable endovascular prostheses. Postintervention, all patients had significant improvement in LVAD flow rates.

Percutaneous treatment of left ventricular assist device outflow graft obstruction

“…Outflow graft obstruction is a rare complication which has been reported in <1% of LVAD recipients 7 . Outflow graft obstruction has been reported in all the continuous flow LVADs including Heartmate II, Heartware 6 and Heatmate III 8 .…”

“…The etiology of LVAD outflow graft obstruction could be due to multiple mechanical reasons 6 . Obstruction may be due to kinking of the outflow graft, 8 stenosis at the aortic anastomosis site from neointimal hyperplasia 7 and compression from accumulation of extra luminal thrombus 16 or gelatinous protein material between the outflow graft and its outer sleeve 17 . There are no known patient or surgical implantation factors that can lead to the increase risk of outflow graft obstruction.…”

“…Although optimal treatment is unknown, available treatment strategies for outflow graft obstruction include percutaneous stenting 7,18 with appropriate carotid artery protection, 19,20 LVAD exchange, or surgical revision 8 . Prior to any treatment approach, it is imperative to rule out the presence of thrombus in the pump or outflow graft, to avoid thrombus embolization and potential stroke.…”

“…Outflow graft obstruction is a rare complication which has been reported in <1% of LVAD recipients. 7 Outflow graft obstruction has been reported in all the continuous flow LVADs including Heartmate II, Heartware 6 and Heatmate III. 8 These patients can develop clinically significant adverse sequelae of pump failure due to incomplete After ruling out pump thrombosis and other causes of pump failure, a speed titration ramp study should be performed with RHC or TTE.…”

Pump thrombosis and dynamic outflow graft compression: complications in left ventricular assist device therapy

“…Alarms and symptoms of progressive heart failure are the most common presentation (in 92% of patients) leading to hospital admission in these cases. 9 After exclusion of hypovolaemia, arrhythmias, or hypertension, posture dependency of the low-flow alarm pointed towards an outflow graft obstruction, and the diagnosis was confirmed using CTA. 3 In our increasingly symptomatic patient, a steady decline in LVAD flow (Figure 3) without an increase in VAD power and accompanying progressive left ventricular dilatation hinted towards progressive outflow graft obstruction.…”