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 RESULTS: Thirteen published reports and one unpublished case comprising a total of 28 patients were included.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.

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

BACKGROUND: Left ventricular assist devices (LVAD) outflow graft obstruction is an uncommon complication but carries significant morbidity and mortality. Here we provide a case series of patients with LVAD intrinsic outflow graft obstruction who are deemed to be a high surgical risk for pump exchange and, therefore, underwent percutaneous intervention with the concomitant use of neuroprotective device-Sentinel cerebral protection system (CPS) (Boston Scientific) to prevent embolic stroke. METHODS: We retrospectively analyzed patients who underwent LVAD placement in our institution and developed LVAD outflow graft obstruction. The diagnosis of LVAD outflow graft obstruction was confirmed by utilizing various cardiac imaging modalities such as echocardiography and/or computed tomography angiography. All patients were treated with percutaneous intervention and a catheter-based CPS. RESULTS: From a total of 501 LVAD implants in our institute, 6 (1.2%) patients with LVAD outflow graft obstruction who underwent percutaneous treatment were included; 4 patients with HeartMate-III LVAD, 1 patient with HeartMate-II LVAD, and 1 patient with HeartWare (HVAD). The median age of patients was 56.5 years at the time of LVAD implantation. The median time from the LVAD implantation to the episode of LVAD outflow obstruction was 1343 days. Utilization of Sentinel CPS resulted in the capture and removal of thrombus/debris in all patients. CONCLUSIONS: Percutaneous intervention of LVAD outflow graft obstruction is less invasive than surgical pump exchange and an acceptable alternative in properly selected patients. In our experience, utilization of a catheter-based CPS can help in reducing the incidence of periprocedural embolic events.

Missing the blind spot in a HeartMate 3 LVAD outflow graft obstruction caused by fungal infection.

A patient was admitted in cardiogenic shock and a constant decrease of pump flow requiring combined inotropic support. To evaluate the cause, echocardiography and a ramp test were performed. The results suggested a LVAD related problem - particularly a suspected outflow graft obstruction. Wether CT scan nor angiography confirmed the assumption. However, a post-mortem LVAD examination revealed an outflow obstruction caused by a fungal thrombus formation invisible for standard imaging procedures.

An interventional approach to left ventricular assist device outflow graft obstruction.

BACKGROUND: LVADs provide life-sustaining treatment for patients with heart failure, but their complexity allows for complications. One complication, LVAD outflow graft obstruction, may be misdiagnosed as intraluminal thrombus, when more often it is extraluminal compression from biodebris accumulation. It can often be treated endovascularly with stenting. This case series describes diagnostic and procedural techniques for the treatment of left ventricular assist device (LVAD) outflow graft obstruction. METHODS: We present four patients with LVADs who developed LVAD outflow graft obstruction within the bend relief-covered segment. All were initially diagnosed with computed tomographic angiography (CTA). All underwent invasive evaluation with intravascular ultrasound (IVUS), then were treated with stenting. After misdiagnosing a twist, we developed the technique of balloon "graftoplasty" to ensure suitability for stent delivery in subsequent cases. RESULTS: All patients presented with low-flow alarms and symptoms of low output, and were diagnosed with outflow graft obstruction by CTA. In all four, IVUS confirmed an extraluminal etiology. Patient 1 was treated with stenting and had a good outcome. Patient 2's obstruction was from twisting, rather than biodebris accumulation, and had sub-optimal stent expansion and ultimately required surgery. Balloon "graftoplasty" was used in subsequent cases to ensure subsequent stent expansion. Patients 3 and 4 were successfully stented. All improved after treatment. CONCLUSIONS: In patients with LVAD outflow graft obstruction, IVUS can distinguish intraluminal thrombus from extraluminal compression. Balloon "graftoplasty" can ensure that the outflow graft will respond to stenting. Many cases of LVAD outflow graft obstruction should be amenable to endovascular treatment.

Percutaneous treatment of left ventricular assist device outflow graft obstruction.

Owing to the growing population with end stage heart failure, the use of left ventricular assist devices (LVADs) have become more widely accepted. Although survival has improved with newer generation LVADs, multiple complications including pump failure due to outflow graft obstruction have become more clinically relevant. Patients with this complication will present with heart failure symptoms due to inadequate unloading of the left ventricle by LVAD. This rare complication often requires open surgical repair in an already high-risk patient population. Alternative means to relieve the obstruction via percutaneous intervention has been described in rare cases. We present two unique cases of LVAD outflow graft obstruction which were percutaneously treated successfully. This article illustrates a potential treatment strategy for outflow graft obstruction with stenting as an alternative to open-heart surgery.

External compression due to seroma of ventricular assist device outflow graft.

A 45-year-old woman with repaired complex congenital heart disease, who underwent placement of Jarvik 2000, a ventricular assist device (VAD) for 4 years, experienced abdominal pain due to outflow graft compression caused by seroma formation between the outflow graft and ringed Gore-Tex graft. We exchanged the pump of Jarvik 2000 and punched several small holes in the new ringed Gore-Tex graft. Seroma formation between the two grafts should be considered as a cause of outflow graft obstruction in patients with the long-term support of VAD, and additional surgical interventions to the ringed Gore-Tex graft may prevent this complication.

Surgical treatment of outflow graft kinking complicated by external obstruction with a fibrin mass in a patient with LVAD.

BACKGROUND: Outflow graft (OG) obstruction is a dangerous complication that may occur for various reasons after left ventricular assist device (LVAD) implantation. CASE SUMMARY: We describe the case of a 51-year-old patient on LVAD support who developed significant OG kinking and external OG obstruction due to a fibrin mass causing severe stenosis. Both the OG kinking and external obstruction were eliminated via a left lateral thoracotomy.

Percutaneous Intervention for Left Ventricular Assist Device Outflow Obstruction.

Left ventricular assist devices (LVADs) are used to support patients with advanced systolic heart failure (HF). These patients might develop LVAD dysfunction and consequent HF symptoms. Occasionally, outflow graft obstruction is responsible for LVAD dysfunction. Here, we describe percutaneous techniques to repair the outflow graft and avoid re-sternotomy.

Percutaneous endovascular intervention for left ventricular assist device outflow graft obstruction: A single-center experience.

BACKGROUND: Outflow graft obstruction (OGO) is an uncommon yet life-threatening complication in patients with left ventricular assist devices (LVADs). In this retrospective, single-center case series, we identify the baseline demographics and presenting features of patients who develop LVAD OGO and the procedural details and outcomes surrounding percutaneous endovascular intervention (PEI). METHODS: We conducted a retrospective review of patients with LVADs at our institution between January 2010 and February 2023 who developed OGO and were treated with PEI. Details of the PEI including procedure time, fluoroscopy time, contrast use, stent size, number of stents, change in gradient, and change in flow after intervention were collected. RESULTS: A total of 12 patients who had 14 cases of OGO were identified from January 2010 to February 2023. The average age at presentation was 64.78 years. Nine of the 14 cases occurred in male patients. Eleven of the 14 cases occurred with Heartware devices (2 recurrences), 2 in Heartmate 2 and 1 in Heartmate 3. Notable procedural details include a mean procedure time of 90.86 min and mean contrast use of 162.5 mL. The initial gradient across the OGO was reduced by an average of 72 %, to a mean post-PEI of 11.57 mmHg. The average number of stents to achieve this gradient was around 2.08, with the most common stent diameter being 10 mm. Thirty-day mortality after PEI was 7 % (1/14) in this high-risk patient population. CONCLUSION: In our single-center experience, PEI can be a safe and effective treatment for LVAD OGO.

Extrinsic outflow graft obstruction of the HeartMate 3 LVAD: A state-of-the-art review.

While notable improvements in survival, the incidence of hemocompatibility-related adverse events, hospitalizations, and cost have been demonstrated with the only commercially available durable left ventricular assist device, a category of pump malfunctions characterized by outflow graft obstruction has been noted with broader use and clinical follow-up of recipients of this technology. Of particular concern is the accumulation of acellular biodebris between the outflow graft and bend relief covering the outflow graft at its origin with the pump (which we term extrinsic outflow graft obstruction at the bend relief). This process tends to be insidious, occurs late in the postoperative course, can be challenging to diagnose, and can result in significant morbidity and mortality. Herein, we provide a review of this complication and outline diagnostic, treatment, and preventive strategies.

A multicenter evaluation of external outflow graft obstruction with a fully magnetically levitated left ventricular assist device.

BACKGROUND: The HeartMate 3 (HM 3; Abbott) left ventricular assist device (LVAD) has improved hemocompatibility-related adverse outcomes. In sporadic cases, external compression of the outflow graft causing obstruction (eOGO) can result from substance accumulation between the outflow graft and its bend relief. We sought to evaluate the prevalence, course, and clinical implications of eOGO in an international study. METHODS: A multicenter retrospective analysis of HM 3 LVADs implanted between November 2014 and April 2021 (n = 2108) was conducted across 17 cardiac centers in 8 countries. We defined eOGO as obstruction >25% in the cross-sectional area in imaging (percutaneous angiography, computed tomography, or intravascular ultrasound). The prevalence and annual incidence were calculated. Serious adverse events and outcomes (death, transplantation, or device exchange) were analyzed for eOGO cases. RESULTS: Of 2108 patients, 62 were diagnosed with eOGO at a median LVAD support duration of 953 (interquartile range, 600-1267) days. The prevalence of eOGO was 3.0% and the incidence at 1, 2, 3, 4, and 5 years of support was 0.6%, 2.8%, 4.0%, 5.2%, and 9.1%, respectively. Of 62 patients, 9 were observed, 27 underwent surgical revision, 15 underwent percutaneous stent implantation, 8 received a heart transplant, and 2 died before intervention. One patient underwent surgical revision and later stent implantation. The mortality with therapeutic intervention was 9/53 (17.0%). CONCLUSIONS: Although uncommon, HM 3 LVAD-supported patients might develop eOGO with an increasing incidence after 1 year of support. Although engineering efforts to reduce this complication are under way, clinicians must maintain a focus on early detection and remain vigilant.

Bend relief fenestration might prevent outflow graft obstruction in patients with left ventricular assist device.

OBJECTIVES: Patients with left ventricular assist devices may experience external obstruction of the outflow graft through a gelatinous substance within the bend relief (BR; a stiff tube graft guiding the outflow graft). Preventative strategies have been missing. Having faced this problem, we decided to fenestrate the BR to avoid outflow graft obstruction (OGO). METHODS: Since December 2010, 167 patients underwent left ventricular assist device implantation using HeartMate II or 3. BR fenestration was introduced on July 2018 (108 patients before, 59 after the introduction of BR fenestration). Follow-up computed tomography scans were obtained from all patients and were screened for OGO by 3 independent investigators. Results were correlated with log file history, echocardiographic and clinical outcomes. RESULTS: Demographic data were comparable between groups, with mostly male patients. Patients with BR fenestration were older [63 (standard deviation (SD):10.6) vs 58 (SD: 10.7) years] and had shorter support duration [494 (SD: 383) vs 951 (SD: 875) days]. OGO was observed in 5 patients and occurred only in patients without fenestration. Importantly, it occurred late on postoperative Days 412, 462, 1043, 1184 and 1506. Three patients are still asymptomatic. Surgical revision was required in the other 2 patients for pump thrombosis or continuous low flow. One of them died 36 days after revision due to right heart failure. CONCLUSIONS: Our results suggest that fenestration of the BR may be a preventative strategy to avoid external OGO. OGO occurred late, which suggests a careful long-term follow-up.

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

Over the past decade, left ventricular assist device (VAD) therapy has become more prevalent and increasingly safe. Severe complications, such as VAD pump thrombosis and outflow graft obstruction, are rare, yet still associated with high morbidity and mortality. Clinical presentation, VAD alarm and log files, laboratory analysis, and non-invasive cardiac imaging are crucial for establishing the correct diagnosis and determining clinical management. Early intervention is critical to prevent adverse cardiac remodelling or VAD pump failure.

Extracorporeal membrane oxygenation-assisted emergency percutaneous treatment of left ventricular assist device graft occlusion.

End-stage heart failure is more often treated with Implantable left ventricular assist device (LVAD), even if the prolonged use may increase the risk of complications. In this case, a 51-year-old male patient presented to our emergency department showing acute heart failure signs and symptoms and a dramatic reduction of LVAD flow. Laboratory tests ruled out significant haemolysis, usually associated with pump thrombosis. The echocardiogram and the computed tomography were not able to clarify the correct diagnosis. We immediately placed a veno-arterial extracorporeal membrane oxygenation, followed by a selective retrograde angiography of the pump. The images showed stenosis of the LVAD-outflow graft, suggesting a twist. Through a hand-made J-tip guidewire, we performed multiple dilatations of the occlusion using peripheral balloons. Finally, we implanted an aortic coarctation covered-stent, re-establishing an adequate cardiac output to the patient. Our case indicates that catheter-based approach in extracorporeal membrane oxygenation assistance provides an important therapeutic alternative to treat outflow graft stenosis, especially in the case of acutely unstable patient.

Transaxillary Stenting of LVAD Outflow Graft Obstruction.

An 82-year-old man with a HeartMate II left ventricular assist device presented with low-flow alarms and cardiogenic shock secondary to left ventricular assist device outflow graft obstruction. Given high risk for redo sternotomy, the heart team decided on percutaneous intervention with peripheral stents, a procedure that is currently limited to case reports. (Level of Difficulty: Advanced.).

Successful off-pump surgical release for extrinsic compression of outflow graft obstruction of a left ventricular assist device.

A 36-year-old woman had received support with the Jarvik 2000 left ventricular assist device for 3 years. Cardiac computed tomography revealed outflow graft obstruction, which appeared as external compression of the outflow graft. The patient underwent surgical release of the obstruction after resternotomy. Yellow sediment had become encrusted in the enclosed space between the covering graft and outflow graft and appeared to have been derived from plasma contents. Successful release of the obstruction was achieved by cutting open the covering graft without cardiopulmonary bypass. Neither pump exchange nor outflow graft exchange was required. This off-pump surgery can be a beneficial procedure in terms of less invasiveness and good curability.

Percutaneous Management of Outflow Graft Obstruction in Patients With Continuous Flow Left Ventricular Assist Devices.

Outflow graft obstruction (OGO) has been reported as a cause of left ventricular assist device dysfunction. The incidence, diagnosis, and treatment of OGO remains poorly understood. We present our experience with the diagnosis and management of OGO in the cardiac catheterization laboratory. (Level of Difficulty: Advanced.).

Late-stage obstruction due to preventative wrapping of left ventricular assist device outflow graft.

Preventative polytetrafluoroethylene coverings are often used to protect the left ventricular assist device outflow graft during sternal re-entry. We herein describe 5 cases of late-onset, significant left ventricular assist device outflow graft obstruction due to external outflow graft compression. We present clinical presentations, therapies and outcomes.