Bend Relief Research Articles

Heartmate 3 Left Ventricular Assist Device Bend Relief Disconnection Causing Laceration of the Outflow Graft.

As technology in mechanical circulatory support continues to advance, so does the utilization of durable left ventricular assist devices (LVADs). We present the first reported case of HeartMate 3 (HM3) LVAD bend relief disconnection causing laceration of the outflow graft. Our patient is a 34 year old male with end-stage heart failure status post-HM3 implantation with recent debridement of a driveline infection who presented with weakness and sanguineous drainage 5 days after an episode of heavy lifting associated with a palpable substernal pop. During the initial evaluation, he experienced sudden massive decompression of a left chest hematoma through a thoracotomy incision with exsanguinating hemorrhage and an abrupt drop in LVAD flow. An emergent anterolateral thoracotomy was performed where it was discovered that the bend relief was disconnected and had lacerated the outflow graft. The graft was repaired and the ring was removed using a diamond blade rotary saw. He was discharged home and made a full recovery. Mechanical device malfunction has been documented in several prior versions of durable LVADS. Although there have been reported cases in the Heartmate 2, this is the first reported case of a HM3 bend relief disconnection and resultant laceration of the outflow graft.

Case Report of a Heartmate II Outflow Graft Obstruction by Extrinsic Compression

Left ventricular assist devices take an important place in the armamentarium of end-stage heart failure therapy. Outflow graft obstruction by extrinsic compression is a rare but possibly life-threatening complication of these types of devices. Pathophysiology is not completely elucidated but seems to be related to the common design of these devices, because of a porous Dacron graft surrounded within an impervious Teflon bend relief. In the absence of pump thrombosis, the pump replacement is not necessarily indicated, and only removal of the obstruction may be sufficient. Both surgical and interventional procedures are described. We reported a case successfully treated by angioplasty-stenting. We discussed the diagnosis, the pathophysiology, and the treatment of this specific complication of left ventricular assist devices. Finally, we open the discussion to the prevention of this complication.

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

BackgroundThe 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. MethodsA 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. ResultsOf 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%). ConclusionsAlthough 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.

Successful Outflow Graft Stent Placement for a Malfunctioning Left Ventricular Assist Device

A 79-year-old man presented with hypertension and a 24-hour history of low flow alarms (flow <2.5 L/min) from his left ventricular assist device (LVAD, HeartMate II; Abbott Cardiovascular, Chicago, Illinois). At a 90-mm Hg pressure gradient, 90% stenosis of the 14-mm outflow graft tract was noted upon left heart catheterization, between the bend relief and aortic anastomosis. No standardized management has been established for graft stenosis because of technique-related challenges, including proximity of the LVAD motor to the wire, possible stent migration or slippage, and the risk of cerebral embolism.

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

OBJECTIVESPatients 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).METHODSSince 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.RESULTSDemographic 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.CONCLUSIONSOur 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.

Cases of Surgical Intervention for Outflow Graft Obstruction Due to Accumulation of Biodebris Following HeartMate 3 Implantation

<h3>Introduction</h3> Outflow graft obstruction due to accumulation of biodebris between the outflow graft and bend relief has been reported following implantation of the HeartMate 3 (HM3) LVAD. In some instances, this can result in significant hemodynamic compromise, warranting operative intervention. We present three cases in which outflow graft obstruction was successfully relieved with operative excision of the HM3 bend relief and evacuation of biodebris. <h3>Case Report</h3> (1) 43 yr-old male with NICM s/p HM3 as bridge to transplantation presented with persistent low flow alarms at 26 months post-LVAD. CTA demonstrated outflow graft occlusion. Via subcostal incision, the patient underwent evacuation of biodebris with resolution of flow obstruction. The patient was subsequently discharged to home on postoperative day 7. (2) 38 y/o female with NICM s/p HM3 developed low flow alarms acutely during admission for GI symptoms 17 months post LVAD. CTA interpreted as "filling defect in midportion of outflow graft." The patient underwent urgent exploration via subxiphoid approach. With excision of the bed relief and evacuation of biodebris, the patient had immediate improvement in her pump flow. The patient was discharged to home on postoperative day 11. (3) 77 y/o male with NICM who underwent HM3 implantation as destination therapy. The patient presented with episodic low flow alarms 25 months post LVAD implantation. CTA demonstrated accumulation of biodebris within the course of the bend relief. The patient underwent excision and evacuation via subxiphoid approach. The patient was discharged to home on postoperative day 6. Images from CTA of the outflow graft (arrows) both pre and postoperatively are shown in Figure 1. <h3>Summary</h3> When intervention is deemed necessary, outflow graft occlusion due to accumulation of biodebris in HM3 patients can be treated surgically, with minimal morbidity. Biodebris evacuation can be effectively achieved through either a subxiphoid or subcostal approach.

LVAD Outflow Graft Stenosis

Introduction Left Ventricular Assist Device (LVAD) outflow graft obstruction is a known long-term complication, etiologies for obstruction include thrombosis, kinking as well as external compression. Here we present a clinical case presenting with low LVAD flows due to external compression of the outflow graft with marked improvement after surgical intervention. Case Report A 60-year-old woman with chronic systolic heart failure secondary to non-ischemic cardiomyopathy with a HeartWare LVAD implanted 2018 presented with one month of low flows prior to admission. She was in atrial fibrillation (AF) with rapid ventricular response and volume overloaded. Despite AF rhythm control and volume optimization, flows never returned to prior baseline (Figure A). Gated cardiac CT demonstrated narrowing within the bend relief down to 3.7mm. During an echo guided ramp study aortic valve opening frequency decreased only minimally with speed up titration with slight improvement in flows. Ventriculography was significant for narrowing of the proximal outflow graft with most contrast exiting through LVOT, however, a kink in the outflow tract vs external compression could not be distinguished (Figure B). Percutaneous stenting was deemed to be too high-risk due to the proximity to the rotor blade. In the OR, fibrinous tissue between the outflow graft and the externally reinforced goretex graft covering the strain relief was identified. Via a limited left subcostal incision, the goretex graft was sharply opened from distal end to proximal end resulting in immediate LVAD flow normalization (Figures C and D). The patient discharged home on post-operative day 5. Summary Mechanical LVAD outflow graft obstructions can be catastrophic and addressing its causes requires a multidisciplinary approach. Here we present a case where a symptomatic, mechanical outflow graft obstruction was identified via multimodal imaging. The mechanical obstruction was ultimately amendable to a minimally invasive surgical approach and avoided pump exchange or even cardiac transplant. Left Ventricular Assist Device (LVAD) outflow graft obstruction is a known long-term complication, etiologies for obstruction include thrombosis, kinking as well as external compression. Here we present a clinical case presenting with low LVAD flows due to external compression of the outflow graft with marked improvement after surgical intervention. A 60-year-old woman with chronic systolic heart failure secondary to non-ischemic cardiomyopathy with a HeartWare LVAD implanted 2018 presented with one month of low flows prior to admission. She was in atrial fibrillation (AF) with rapid ventricular response and volume overloaded. Despite AF rhythm control and volume optimization, flows never returned to prior baseline (Figure A). Gated cardiac CT demonstrated narrowing within the bend relief down to 3.7mm. During an echo guided ramp study aortic valve opening frequency decreased only minimally with speed up titration with slight improvement in flows. Ventriculography was significant for narrowing of the proximal outflow graft with most contrast exiting through LVOT, however, a kink in the outflow tract vs external compression could not be distinguished (Figure B). Percutaneous stenting was deemed to be too high-risk due to the proximity to the rotor blade. In the OR, fibrinous tissue between the outflow graft and the externally reinforced goretex graft covering the strain relief was identified. Via a limited left subcostal incision, the goretex graft was sharply opened from distal end to proximal end resulting in immediate LVAD flow normalization (Figures C and D). The patient discharged home on post-operative day 5. Mechanical LVAD outflow graft obstructions can be catastrophic and addressing its causes requires a multidisciplinary approach. Here we present a case where a symptomatic, mechanical outflow graft obstruction was identified via multimodal imaging. The mechanical obstruction was ultimately amendable to a minimally invasive surgical approach and avoided pump exchange or even cardiac transplant.

LVAD Outflow Graft Compression Presenting as Pump Thrombosis

<h3>Introduction</h3> Pump thrombosis is a serious adverse event in patients with left ventricular assist devices (LVAD). Pump thrombosis is a complication of LVAD implantation, affecting approximately five percent of patients. It often presents with clinically significant hemolysis, device alarms and can progress to heart failure and cardiogenic shock. We present a case of a patient with a Heartmate II LVAD who presented with a rising LDH that led to investigation to diagnose a potential pump thrombosis. <h3>Case Report</h3> The patient is a 73 year old male who was implanted with a HeartMate II LVAD as destination therapy (DT) for ischemic cardiomyopathy (ICM). Approximately 3 years after implant, the patient was noted to have a markedly elevated LDH on routine lab work. After 8 months of event-free observation, the patients LDH trended up again and the plasma free hemoglobin level was also elevated. An ECHO with limited ramp study was performed. The power and flow responded appropriately however LVEDD showed no applicable change. To further investigate a potential thrombosis, a CT angiogram was obtained. The CT demonstrated a significant obstruction to the outflow graft within the bend relief. The initial intervention was a balloon angioplasty of the outflow graft. The angioplasty was technically successful, and the balloon fully expanded. A repeat CT 2 weeks later showed the obstruction was still present. Interestingly, the patient remained asymptomatic and his LDH normalized. The decision was made to continue observation. Six months later, his LDH was noted to be increasing. A repeat CT showed that the outflow obstruction was worsening. The outflow graft appeared to be at least 90% obstructed. Again, the patient was taken to the OR for an intervention. Balloon angioplasty was repeated to predilate the lesion. Three endovascular stents were placed in the outflow graft within the bend relief. Completion angiogram confirmed the stents to be fully expanded with no residual obstruction. There were no complications from the procedure. The patient remains event-free 8 months later. <h3>Summary</h3> In conclusion, the patient demonstrated signs of pump thrombosis mediated by an extrinsic compression of the outflow graft. In this case, the problem was treated with angioplasty with excellent result. The patient remains under surveillance but has been event-free for one year.

A Multi-Center Evaluation of Outflow Graft Obstruction with a Fully Magnetically Levitated Left Ventricular Assist Device

<h3>Purpose</h3> The HeartMate3 (HM3) left ventricular assist device (LVAD) has markedly improved hemocompatibility related adverse outcomes. In sporadic cases, external compression of the outflow graft causing obstruction (eOGO) can result from gelatinous substance accumulation between outflow graft and its bend relief covering. We sought to evaluate the prevalence, temporal course and clinical implications of eOGO with the HM3 LVAD in a global cohort study. <h3>Methods</h3> A Multi-center retrospective analysis was conducted among 2014 HM3 LVAD patients across 16 cardiac centers in 8 countries (between 11/2014 and 4/2021). Presence of eOGO was defined as >25% of cross-sectional area identified by established imaging (percutaneous angiography, computed tomography or intravascular ultrasound). The prevalence and annual incidence were calculated. Serious adverse events and outcome (death, transplant or device exchange) at the end of the study were analyzed for those eOGO cases that required therapy versus those who were observed. <h3>Endpoints</h3> Among 2014 patients, 61 patients were diagnosed with eOGO at a median LVAD support duration of 1024 [IQR: 636-1409] days. The overall prevalence of eOGO was at 3.0 %. The incidence at 1, 2, 3, 4, and 5 years on support was 0.6, 2.8, 4.1, 4.6 and 9.8 %. Of 52 patients, who required a therapeutic intervention, 26 underwent surgical revision, 16 patients were treated by percutaneous stent implantation, 8 underwent urgent heart transplantation and 2 died before intervention. In 9 patients a watchful waiting strategy without treatment was chosen. The mortality among those requiring therapeutic intervention was 9 of 52 (17.3%). This global multicenter cohort study suggests that while rare, HM3 LVAD supported patients may develop eOGO with an increasing incidence after 1 year on support. While targeted engineering efforts to alleviate this complication are underway by addressing early detection as well as outflow graft and bend relief design, clinicians must remain vigilant to this complication, especially in long-term survivors supported with the HM3 LVAD.

Single-Center Analysis of Patients with HeartMate 3 LVAD External Outflow Graft Obstruction

<h3>Purpose</h3> There is limited published data regarding external outflow graft obstruction (EOGO) of the Heartmate 3 (HM3) left ventricular assist device (LVAD) (Abbott Labs, Chicago, IL) and its clinical consequences despite the suspicion that it is a commonly observed complication in practice. <h3>Methods</h3> The cohort included adults with HM3 LVADs at a single center. Chart review was completed to assess baseline characteristics, serial right heart catheterization and echocardiographic data while on support, as well as if there was suspicion or confirmation of EOGO including symptoms, CT of the LVAD, and pathology of the explanted device. Hospital readmissions for obstruction concerns and upgrade of status on the heart transplant list while on support were recorded. <h3>Results</h3> The cohort consisted of 24 patients with a mean age of 55 +/- 13, 25% were classified as destination therapy, and 75% had nonischemic cardiomyopathy. 12/24 patients had suspected and/or confirmed EOGO, of which 7/12 were symptomatic. The other 5/12 were discovered at the time of transplant (Table). 3/12 patients were readmitted for concerns of EOGO and 5/12 required status upgrade on the transplant waitlist. CT findings and pathology of the explanted LVADs showed compressive material between the outflow graft and the bend relief (Figure). <h3>Conclusion</h3> Although EOGO of HM3 LVADs is commonly seen in clinical practice, it has been under reported in the literature. Our study shows it is a common finding with potential of serious complications. A large multicenter study of EOGO is needed to completely understand the full scope of EOGO, and its clinical impact on patient care.

The Effect of Multiple Outflow Graft Stenting on Hemodynamics in the Treatment of Left Ventricular Assist Device Outflow Graft Stenosis

<h3>Introduction</h3> Outflow graft stenosis is a potential complication of durable left ventricular assist device implantation. It presents with reduced LVAD flow, increased power requirement and decompensated left heart failure. Percutaneous intervention for OFG stenosis with single OFG stenting has been described. We present a case of decompensated heart failure due to LVAD OFG stenosis successfully managed with multiple OFG stenting. <h3>Case Report</h3> A 31 year old male with nonischemic cardiomyopathy underwent LVAD implantation 6 years ago with 20cm PTFE graft covering the OFG. He presented with acute decompensated left heart failure due to decreased LVAD flow on prior settings. Contrast CT showed OFG stenosis. Cardiac catheterization demonstrated 130mmHg pressure gradient. OFG angiography revealed 80% stenosis inside the PTFE graft. Four overlapping OFG stents were placed reducing gradient to 10mmHg. There was significant hemodynamic improvement with return of LVAD flow to baseline. <h3>Summary</h3> LVAD OFG stenosis may be caused by exudate overlying OFG covered by PTFE graft or the original bend relief. Successful surgical and percutaneous intervention for this complication has been reported. We observed the hemodynamic impact of multiple OFG stenting on OFG stenosis with return of LVAD flow to baseline. Multiple stents may be needed for long OFG covering since the exudate outside the OFG may worsen stenosis next to the stent. Our case of LVAD dysfunction due to OFG stenosis successfully managed with multiple OFG stenting affirms the essential role of this percutaneous intervention in managing this complication.

Insights Into the Low Rate of In-Pump Thrombosis With the HeartMate 3: Does the Artificial Pulse Improve Washout?

While earlier studies reported no relevant effect of the HeartMate 3 (HM3) artificial pulse (AP) on bulk pump washout, its effect on regions with prolonged residence times remains unexplored. Using numerical simulations, we compared pump washout in the HM3 with and without AP with a focus on the clearance of the last 5% of the pump volume. Results were examined in terms of flush-volume (Vf, number of times the pump was flushed with new blood) to probe the effect of the AP independent of changing flow rate. Irrespective of the flow condition, the HM3 washout scaled linearly with flush volume up to 70% washout and slowed down for the last 30%. Flush volumes needed to washout 95% of the pump were comparable with and without the AP (1.3–1.4 Vf), while 99% washout required 2.1–2.2 Vf with the AP vs. 2.5 Vf without the AP. The AP enhanced washout of the bend relief and near-wall regions. It also transiently shifted or eliminated stagnation regions and led to rapid wall shear stress fluctuations below the rotor and in the secondary flow path. Our results suggest potential benefits of the AP for clearance of fluid regions that might elicit in-pump thrombosis and provide possible mechanistic rationale behind clinical data showing very low rate of in-pump thrombosis with the HM3. Further optimization of the AP sequence is warranted to balance washout efficacy while limiting blood damage.

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

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. 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. 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. 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.

A Pseudotwist Pattern of LVAD Outflow Graft Stenosis - A Cautionary Tale

Introduction Left ventricular assist devices (LVADs) play a fundamental role in treating end-stage heart failure. Outflow graft stenosis (OGS) represents a serious complication that can occur at a variable time point after the implantation, although typically of the order of months to years. Different types of OGS, both intrinsic and external, were described. Notwithstanding the etiology, this clinical scenario poses a life and health-threatening complication requiring timely and precise diagnosis followed by appropriate intervention. Case Report We present a case of a 72-years-old woman on LVAD HeartMate II (HM II) support. Three years after the index implantation, she presented with clinical symptoms of outflow graft stenosis. The patient was admitted to the hospital due to”low-flow“ alarms of HMII. The CT scan revealed distal outflow graft stenosis suggestive of kinking of the graft. Subsequent percutaneous transluminal stenting of the graft was performed. However, after the intervention, signs of hemodynamic compromise persisted. Both angiography and repeated CT scans verified peculiar pattern of the proximal shift of the stenotic segment relative to the implanted stent. Given this specific feature, a diagnosis was reclassified as a previously reported pattern of the outflow graft twist scenario, and surgical subxiphoid approach reexploration was indicated. On inspection, after disconnecting the bend relief from the pump body massive”gelly mass“ plasma transudate located in the interspace between the graft and the bend relief was observed. Immediately after removing compressing gelly mass, hemodynamic and pump parameters promptly resolved, and the bend relief was re-attached. Further patient follow-up remains uneventful to the date. Summary Our observation suggests that the diagnostic assessment of the outflow graft stenosis may be confusing and challenging. As plasma transudate likely develops over an extended period of time once a distal orifice of the bend relief already gets entrapped within the adjacent adhesion, the outflow graft may become contained within incompressible interspace while limited by tight connection to the pump body. That said, the graft constriction migration upon stenting can easily get misdiagnosed as a pattern suggestive of the intrinsic twist instead of correct”pseudotwist“ diagnosis associated with the external contained compartment compression.

Case of Outflow Graft Obstruction from Extrinsic Compression in HM III LVAD

<h3>Introduction</h3> Pump thrombosis is an important adverse outcome to be aware of in patients with left ventricular assist devices (LVADs). While Heart Mate III (HMIII) has significantly lower rates of pump thrombosis, outflow graft obstruction remains a possibility. We present a case of outflow graft obstruction secondary to extrinsic compression at the site of the bend relief in a HMIII. <h3>Case Report</h3> A 36-year-old male with a history of non-ischemic cardiomyopathy status post HMIII as a bridge to transplant, with history of two LVAD pump exchanges due to pump thrombosis, presented with dyspnea and low flow alarms. Computed tomography (CT) of the chest demonstrated luminal narrowing with near obstruction of the outflow graft, concerning for thrombus. Urgent right heart catheterization demonstrated cardiogenic shock with elevated biventricular filling pressures. He was placed on Veno-Arterial Extracorporeal Membrane Oxygenation support and his listing status was upgraded to Status 1 for heart transplant. He was started on intravenous heparin for suspected pump thrombosis, and ultimately went on to transplant. With removal of the LVAD intra-operatively, proteinaceous material was noted between the bend relief collar and the outflow graft, leading to extrinsic compression of the graft, with no evidence of thrombus. <h3>Summary</h3> When evaluating patients with suspected outflow graft obstruction, it is important to consider not only pump thrombosis, but also the possibility of extrinsic compression of the outflow graft leading to obstruction. Distinguishing these etiologies is important as management may greatly vary.

Driveline Fractures in the Heartmate II Left Ventricular Assist Device - A Single Center Experience in Asia

Purpose The incidence of driveline fractures among patients on HeartMate II Left Ventricular Assist Device (LVAD) support is reviewed Methods This is a single-center, retrospective review of all the patients on HeartMate II LVAD support who presented with driveline fractures. Patients’ presentation, interventions, and outcome following corrective treatment were examined. Results Between May 2009 and October 2018, 60 HeartMate II LVAD were implanted. Over a cumulative support period of 81 patient-years (maximum, 8.5 years), 15 patients (25%) had driveline fractures (age 14-70, 2 female), 5 of them were destination therapy (> 65 years old). Mean duration from the time of implant to driveline fractures was 44.5 ± 15.5 months. 12 patients had significant weight gain following LVAD implant, ranging from 5.2 to 32.3kg (median 17.4kg). While tethered on to power module, 8 patients (53.3%) encountered intermittent pump stoppage, 5 (33.3%) had transient low pump speed, 1 (6.7%) had recurrent driveline fault and 1 more (6.7%) presented with hemoserous discharge leaking from broken insulation in the external driveline with multiple recurrent low voltage advisory. Ungrounded cable was issued to 13 patients as a temporary measure with mean duration of its usage of 259 days (range 26-980 days), before corrective treatment. There were 2 patients with ongoing use of the ungrounded cable (mean 1 year). 8 patients (53.3%) underwent pump replacement, 2 with significant external driveline fractures successfully underwent external driveline replacement and 1 underwent heart transplant. Of the 9 pumps returned for analysis, 7 (78%) were found to have damaged internalized part of the driveline while 2 (22%) had circumferential fractures at the edge of the pump housing extending across the diameter of the bend relief. There were 3 mortality (20%), 1 due to recurrent pump pocket infection and pump thrombosis following the initial pump replacement for driveline fractures, 1 died of subdural haemorrhage before elective pump exchange and 1 died 3 weeks after pump stoppage. Conclusion The incidence of HeartMate II internal driveline fractures seemed to be higher in our Asian experience as opposed to what have been reported in literature. An ungrounded cable served as a temporary measure for short to shield and a timely pump exchange maybe lifesaving when driveline damage progressed into phase to phase.

Three-Field LVAD Implantation Completely Avoids Dissection of the Heart in Patients with Previous Sternotomy

<h3>Introduction</h3> Less invasive techniques to implant a left ventricular assist device (LVAD) reduce perioperative complications, length of stay, right heart failure, and perhaps even mortality. In this case series we describe a novel three-field implant technique (3FIT) for LVAD for patients with previous sternotomies. This technique employs a left thoracotomy, a subxiphoid incision, and a right thoracotomy or upper ministernotomy. The outflow graft is tunneled from the left thoracotomy to the subxiphoid area and then subsequently to the aorta through the right pleural space. To avoid any possible compression of the outflow graft in the subxiphoid area, an additional bend relief is easily spliced with the original one (Figure). <h3>Case Report</h3> Five patients (4 with previous CABG and one with 3 prior sternotomies) underwent LVAD implantation via the 3FIT. The mean age was 55.4 ± 16.2 years and Heartmate II Risk Score (HMRS) was2.51 + 0.5 (high risk HMRS is > 2.48). Mean pre-operative eGFR was 46+ 14 mL/min. Mean right atrial pressure was 11 + 5 mmHg and pulmonary artery pulsatility index was 3.3+ 2.8. Mean cardiopulmonary bypass time was 142 + 38 minutes. Post-operatively, the mean time to extubation was 10.4 ± 7.5 hours, mean ICU length of stay was 8.6 ± 5.7 days, and mean length of stay was 20.8 ± 4.7 days. No patients had severe or severe-acute right heart failure (RHF) by INTERMACS criteria, and no patients required long term renal replacement therapy. One patient died 16 months post-operatively of chronic heart failure. <h3>Summary</h3> The 3FIT completely avoids dissection and mobilization of either ventricle in patients with prior sternotomies. This is particularly important in patients with poor RV function and patent coronary grafts. Coronary angiography to assess bypass grafts preoperatively is not necessary, especially if renal function is compromised. None of our patients had significant RHF or required long-term dialysis in this high risk group of patients with prior sternotomies.

Cardiac Tamponade from Biodebris Accumulation in Long Term HVAD Support

<h3>Introduction</h3> As patients live longer on mechanical circulatory support (MCS), it is crucial to recognize long term device complications. We present a case of an unusual late complication after an HVAD implantation. <h3>Case Report</h3> A 51 year old female implanted with HVAD 6.5 years ago as a bridge to transplant presented with hypotension and UTI. She received IV fluids and antibiotics, and antihypertensive medications were held with clinical improvement. Surveillance RHC showed high filling pressures (RA 25 mmHg, Wedge 38 mmHg) and low cardiac index (1.8 mL/kg/m2). After diuresis, she developed acute hypotension, low flows and a pulsatility waveform consistent with suction for which device speed was decreased. Despite volume resuscitation she had PEA arrest requiring CPR and inotrope support. An echocardiogram showed near complete compression of the RA and RV by a fluid collection adjacent to the outflow tract. An emergent CT showed a 5.2 × 8.4 × 9.7 cm fluid collection around the outflow graft, extending from the proximal conduit to the aortic anastomosis. There was mass effect causing effacement of the IVC-RA junction and compression of SVC consistent with tamponade. The outflow graft was patent without signs of compression. Due to concern for bleeding from the graft, the patient was taken to surgery. Intraoperatively, there was a large amount of gelatinous material within the Gore-Tex wrapping of the conduit and no bleeding. The biodebris was evacuated with immediate relief of cardiac compression. Gore-Tex membranes were removed, and the chest was closed. The patient recovered and is doing well. <h3>Summary</h3> We present the first case of biodebris within Gore-Tex outflow graft wrapping causing cardiac tamponade. Gore-Tex wrapping of MCS devices is used to facilitate future explanting but may cause accumulation of biodebris over time. The phenomenon was previously described with HeartMate devices owing to the design of the bend relief resulting in outflow graft compression, but is unusual for HVAD devices, and has not been reported to cause tamponade.

Outflow Graft Narrowing of the Heartmate 3 Left Ventricular Assist Device: Incidence, Imaging Findings, and Outcomes

<h3>Purpose</h3> Outflow graft narrowing or occlusion has been reported in patients with the HeartMate 3 (HM3) left ventricular assist device (LVAD) due to accumulation of biodebris external to the graft. This study assesses the impact of HM3 LVAD outflow graft narrowing on clinical outcomes and left ventricular unloading. <h3>Methods</h3> A single-center retrospective cohort study was performed among patients who received a HM3 LVAD between November, 2014 and August, 2019. All patients with a Computed Tomography Angiography (CTA) or Computed Tomography (CT) with IV contrast sufficient to evaluate the outflow graft lumen were included in this analysis. A significant narrowing was defined as a hypodensity of 4mm or greater. <h3>Results</h3> Of 165 patients who received a HM3 LVAD, 46 (28%) had qualifying imaging. Fourteen patients (30%) had any hypodensity in the outflow graft, and 10 (22%) had a significant narrowing. Median (interquartile range) hypodensity was 4.5mm (3.25 to 5.75). 12 patients had asymmetric hypodensity (example shown in Figure), 2 had circumferential hypodensity, and 1 had complete obstruction. Median distance from the pump exit to the start of narrowing was 5mm (0 to 12mm), length of narrowing was 29mm (22 to 49mm), and diameter of the outflow bend relief at most narrow area of lumen was 14mm (14 to 15mm). 41 (89%) patients had a transthoracic echocardiogram (TTE) done within 35 days of imaging, with the majority (37) having a TTE within two weeks of CT imaging. Death at one year post LVAD occurred in 0 patients with narrowing vs 2 (6%) in those without narrowing (p=0.48). Mean decrease in left ventricular end diastolic diameter compared to pre-LVAD TTE was 12% in patients with narrowing vs 19% in those without narrowing (p=0.34). <h3>Conclusion</h3> HM3 patients with outflow graft narrowing due to external compression by biodebris have similar outcomes and no difference in left ventricular unloading compared to patients without outflow graft narrowing. Additional analysis with a larger population is warranted.

Left ventricular assist device outflow graft obstruction development in the original bend relief.

Left ventricular assist device outflow graft obstruction development in the original bend relief.