An interventional approach to left ventricular assist device outflow graft obstruction

Outcomes of outflow graft stenting in HeartMate 3 left ventricular assist devices: A systematic review and individual patient data meta-analysis

PURPOSE

LVAD outflow graft stenosis continues to remain prevalent with a high complication rate. We sought to pool the existing evidence on indications, utilization patterns, and outcomes of transcatheter interventions for outflow graft stenosis in the HeartMate 3 LVAD.

METHODS

An electronic search was performed to identify all studies in the English literature reporting on HeartMate 3 LVAD outflow graft stenting. Patient-level data were extracted for analysis.

RESULTS

Thirteen published reports and one unpublished case comprising a total of 28 patients were included. Median patient age was 68.5 years [Interquartile range: 58, 71] and 25.9% (7/27) were female. Dyspnea [60.7% (17/28)] was the most common presenting symptom. Low flow alarms were present in 60% (15/25) of patients. Findings included external compression [35.7% (10/28)], graft twist [21.4% (6/28)], graft twist and external compression [14.3% (4.28)], intraluminal thrombus [10.7% (3/28)], graft twist and intraluminal thrombus [3.6% (1/28)], and pseudoaneurysm of outflow graft [3.6% (1/28)]. Median time from LVAD implantation to stenting was 2.1 years [1.4, 3]. Immediate flow normalization after stenting was observed in 85.7% (24/28). The 30-day mortality was 12% (3/25). Overall mortality was 12% (3/25) at a median follow-up of 3.9 months [1, 17].

CONCLUSION

Outflow graft stenting in the HeartMate 3 LVAD appears to be a reasonable treatment option for outflow graft stenosis, with low overall rates of complications and mortality. Further refinement of indications and approaches may improve outcomes.

Percutaneous Intervention of LVAD Outflow Graft Obstruction and Thrombosis

Left ventricular assist devices serve as a salvage therapy for patients with advanced heart failure. Complications such as thrombosis and obstruction can lead to acute device malfunction, posing significant clinical risks. A multidisciplinary approach is crucial for management. Few cases in the literature have demonstrated the safety and efficacy of percutaneous intervention, which holds significant value due to its less invasive nature and minimal risk of morbidity, especially in high-risk surgical patients.

Percutaneous Stenting of a Stenotic Berlin Heart Outflow Cannula Graft in a 2 Year Old Child

Left ventricular assist device (LVAD) outflow obstruction is a rare complication of long-term LVAD support. We present the first case of successful percutaneous stent implantation in a pediatric patient with LVAD outflow obstruction.

Endovascular stenting of an HVAD™ outflow graft pseudoaneurysm that exerts compression and kinking stenosis on the soft portion of the prosthesis

Key Clinical Message

Complex presentations of MCS patients may necessitate a multidisciplinary approach involving HF cardiologists, CT surgeons, advanced cardiac imagers, and interventional cardiologists in order to define the optimal management strategy.

Abstract

Left ventricle assist devices (LVADs) provide life-sustaining treatment for patients with terminal heart failure, but their intricacy allows for complications. One complication is LVAD outflow graft obstruction due to the graft's intraluminal thrombus or extraluminal compression. It may be treated endovascularly with stenting. We report an endovascular stenting of an outflow tract in HVAD™ (HeartWare Inc.) due to a pseudoaneurysm causing compression and kinking stenosis.

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

PURPOSE

We report on the clinical course and management of patients supported with durable implantable LVADs who developed outflow graft obstructions at a large academic center.

METHODS

We performed a retrospective review of patients receiving LVAD support from 2012 through 2020. Patients who developed an outflow graft obstruction diagnosed by computed tomography angiography (CTA) or angiogram were identified, and patient characteristics and outcomes were reported.

RESULTS

Of the 324 patients supported by LVAD at our institution, 11 patients (3.4%) were diagnosed with outflow graft obstructions. The most common presentation was low flow alarms, which was present in 10/11 patients, and the remaining patient presented with lightheadedness. Patients had minimal LDH elevation with 8/11 presenting with less than 2-fold the upper limit of normal. Transthoracic echocardiograms were not diagnostic, but CTA enabled non-invasive diagnoses in 8/11 of the patients. Three patients with extrinsic compression of the outflow graft successfully underwent endovascular stent placement, and three patients with outflow cannula kinks received supportive care. Of the five patients diagnosed with intraluminal thromboses, one received a heart transplant, one underwent an outflow graft revision, and three received supportive care due to comorbidities.

CONCLUSION

Outflow graft obstructions remain a rare, but serious complication. The true prevalence of this entity is likely underestimated due to the non-specific clinical presentation. CTA is a pivotal non-invasive diagnostic step. Patients with external compression were successfully treated with endovascular stenting.

Outflow graft obstruction in patients with the HM 3 LVAD: A percutaneous approach

BACKGROUND

The use of the HeartMate 3 (HM3) left ventricular assist device (LVAD) is expanding. Despite being associated with lower rates of adverse events and increased survival, outflow graft obstruction (OGO) has been reported in patients with HM3. The incidence and best management of this serious complication remain unclear.

METHODS

We describe six cases of HM3 OGO occurring in five patients in our institutional HM3 cohort. Four cases underwent computed tomography angiography and in two percutaneous angiography was directly performed to confirm the diagnosis. In four cases, percutaneous repair of the OG was performed using common interventional cardiology (IC) techniques.

RESULTS

Our institutional incidence of OGO was 7% (event rate of 0.05 per patient year); much higher than the previously reported incidence of 1.6%. All cases occurred in the bend relief covered segment. Only two patients had apparent OG twisting, and in two, OGO occurred despite placement of an anti-twist clip at the time of implant. External compression seems to play a role in most cases. Balloon "graftoplasty" and stent deployment via the femoral artery alleviated the obstruction and normalized LVAD flow in all patients who underwent percutaneous repair. The use of self-expanding stents allowed for downsizing of the procedural access site to 10 Fr. No serious procedure-related complications occurred.

CONCLUSION

OGO is common in HM3 patients, external compression due to biomaterial accumulated surrounding the OG is a common etiology. Percutaneous repair using standard IC techniques is safe and feasible in cases of compression with or without partial twisting.