Minimally Invasive Left Ventricular Assist Device Insertion Facilitates Subsequent Heart Transplant.

OBJECTIVE: We have observed that minimally invasive left ventricular assist device (LVAD) insertion leads to more facile re-entry and easier cardiac transplantation. We hypothesize minimally invasive LVAD implantation results in improved outcomes at the time of subsequent heart transplant. METHODS: All adults undergoing cardiac transplantation between October 2015 and March 2019 at our institution were retrospectively reviewed. Those bridged to transplantation with a HeartWare HVAD were identified and divided into 2 cohorts based upon the surgical approach: those who underwent HVAD placement by conventional sternotomy versus minimally invasive insertion via lateral thoracotomy and hemisternotomy (LTHS). Patient demographics, as well as perioperative transplant outcomes, including survival, length of stay (LOS), blood utilization, ischemic time, bypass time, and postoperative extracorporeal membrane oxygenation (ECMO) were compared between cohorts. RESULTS: Forty-two patients were bridged to heart transplant with a HVAD implanted via either sternotomy (n = 22) or LTHS technique (n = 20). Demographics were similar between groups. There was 1 predischarge death in the sternotomy group and none in the LTHS group. Body surface area, cardiopulmonary bypass time, ischemic time, ECMO utilization, and reoperation for bleeding were similar. Red blood cell units transfused were significantly lower in the LTHS cohort (3.0 [1.0-5.0] vs 6.0 [2.5-10.0] P = 0.046). The LTHS cohort had a significantly shorter hospital LOS (12.0 [11.0-28.0] vs 22.5 [15.7-41.7] P = 0.022) with a trend toward shorter intensive care unit LOS (6.0 [5.0-10.5] vs 11.0 [6.0-21.5] days P = 0.057). CONCLUSIONS: Minimally invasive HVAD implantation improves outcomes at subsequent heart transplantation, resulting in shorter LOS and less red cell transfusion. Larger multi-institutional studies are necessary to validate these findings.

Outcomes with temporary mechanical circulatory support before minimally invasive centrifugal left ventricular assist device.

BACKGROUND: Despite improved survival and morbidity after durable left ventricular assist device (dLVAD), outcomes for cardiogenic shock patients are suboptimal. Temporary mechanical circulatory support (tMCS) can permit optimization before dLVAD. Excellent outcomes have been observed using minimally-invasive dLVAD implantation. However, some feel tMCS contraindicates this approach. To evaluate whether left thoracotomy/hemisternotomy (LTHS) dLVAD placement is safe in this setting, we compared patients who did and did not require tMCS. METHODS: Outcomes for patients receiving dLVADs via LTHS were compared among those bridged with extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump (IABP), or no tMCS. We evaluated demographics, comorbidities, laboratory and hemodynamic data, and intraoperative and postoperative outcomes. RESULTS: Eighty-three patients underwent LTHS dLVAD placement. Fifty did not require tMCS, while 22 (26%) required IABP, and 11 (13%) ECMO. Non-tMCS patients were primarily Intermacs 3 (56%), while IABP recipients were mainly Intermacs 2 (45%). All patients with ECMO were Intermacs 1. Patients with tMCS had worse end-organ function. Operative outcomes were similar except more concomitant procedures and red-cell transfusions in patients with ECMO. Intensive care unit and hospital length of stay and inotrope duration were also similar. There were no differences in bleeding, stroke, and infection rates. Three- and 12-month survival were: no tMCS: 94%, 86%; IABP: 100%, 88%; and ECMO: 81%, 81% (P = .45). CONCLUSIONS: Patients with cardiogenic shock can safely undergo LTHS dLVAD implantation after stabilization with ECMO or IABP. Outcomes and complications in these patients were comparable to a less severely ill cohort without tMCS.

Outcomes of obese patients undergoing less invasive LVAD implantation.

BACKGROUND: Obesity and heart failure rates continue to rise, confronting heart failure centers with challenging left ventricular assist device (LVAD) implantations. Although less invasive approaches to implantation have been successfully implemented by many centers, this surgical approach has not yet been well evaluated in the obese population. Therefore, we sought to describe our experience with less invasive device implantation in this patient cohort. METHODS: All implants of centrifugal ventricular assist devices were retrospectively reviewed. Patients implanted with a less invasive approach via a left thoracotomy and upper hemisternotomy were included. Patients were stratified by body mass index (<30 vs ≥30 kg/m2 ). Perioperative and short-term outcomes were evaluated. RESULTS: Forty-two patients implanted with the less invasive approach (BMI <30: 27 vs. BMI ≥30 kg/m2 : 15) were identified. The obese cohort was significantly younger (58.5 vs 46.1 years, P = .022), while other preoperative demographics were similar. Postoperative mechanical ventilator time was longer in the obese cohort (22.9 vs 46.1 hour, P = .045). However, other perioperative and short-term outcomes were comparable. Wound dehiscence occurred in one obese patient. Six-month survival was also comparable between cohorts (96.3% vs 86.7%, P = .264). CONCLUSIONS: In this limited patient series, outcomes appear to be comparable in nonobese and obese patients undergoing less invasive LVAD implantation. Therefore, obesity should perhaps not be viewed as a lone contraindication to the application of this surgical approach.

Individualized Antithrombotic Therapy in Heartware HVAD Recipients.

There are no evidence-based guidelines for antithrombotic therapy in left ventricular assist device patients. We evaluated the efficacy of a multi-agent, test-guided protocol, which remained consistent throughout our use of the Heartware HVAD. Thrombelastography and platelet function analyzer (PFA)-100 guide antiplatelet titration. Goals are normal kaolin thrombelastography maximum amplitude and prolonged PFA-100. We analyzed incidence and rates of nonprocedural bleeding, stroke, and pump thrombosis for all 81 primary Heartware left ventricular assist devices implanted since 2011. For each event, we examined whether each test was within goal range. We also compared medication burden and dosage between patients with and without events. Pump thrombosis and hemorrhagic stroke each occurred in two patients (2.5%; 0.03 events/patient-year [EPPY]), and ischemic stroke in six (7.4%; 0.10 EPPY). Nonprocedural bleeding occurred 75 times in 34 patients (42%; 1.24 EPPY), primarily gastrointestinal (28%; 0.66 EPPY). Subtherapeutic international normalized ratio (INR) was the most common at thrombotic events; supratherapeutic partial thromboplastin time, international normalized ratio (INR), and PFA-adenosine diphosphate (ADP) were common at bleeding events. Medication burden and dosage were lower in patients with events than in stable patients. Protocol-guided antithrombotic therapy resulted in low rates of pump thrombosis and hemorrhagic stroke. Ischemic stroke and gastrointestinal bleeding rates were higher than in a comparable HVAD population. Optimization of our protocol to decrease its complexity and to reduce bleeding is underway.

Minimally Invasive Left Ventricular Assist Device Implantation: Implementation Early in a Surgical Career.

OBJECTIVE: Several centers have presented minimally invasive surgical approaches to centrifugal left ventricular assist device implantation. Although minimally invasive implantation has been successfully performed by experienced surgeons, at large implanting centers, it is unknown whether these techniques are widely adoptable. We evaluated the experience of a surgeon early in his career with conventional and minimally invasive approaches to device implantation. METHODS: All consecutive left ventricular assist device implantations by a single surgeon in the first year of practice (2015-2016) were retrospectively reviewed. Patients were stratified by standard approach, conventional full sternotomy versus a minimally invasive approach, left anterior thoracotomy and upper hemisternotomy. Demographics, perioperative variables, and short-term outcomes were compared using Wilcoxon rank-sum test. RESULTS: Thirteen patients were identified: six performed via the standard approach and seven performed via the minimally invasive approach. Preoperative demographics were comparable in both groups. However, there was significantly more preoperative right ventricle dysfunction in the minimally invasive group (P = 0.01). Although operative time was significantly longer in the minimally invasive cohort, there was a trend toward decreased cardiopulmonary bypass time. Six-month survival in both groups was 100%. CONCLUSIONS: Compared with conventional sternotomy, minimally invasive ventricular assist device implantation, performed by a surgeon in his first year of practice, had similar perioperative outcomes and excellent survival. Based on these data, minimally invasive implantation may be a feasible strategy for device implantation even early in a surgeon's career.

Quantitative Assessment of Inflow Malposition in Two Continuous-Flow Left Ventricular Assist Devices.

BACKGROUND: We previously investigated preoperative variables associated with qualitative inflow cannula malposition in the HeartMate II (Thoratec-Abbott, Abbott Park, IL) continuous-flow left ventricular assist device. In this report, we assess inflow cannula malposition quantitatively in recipients of both the HeartMate II and the HeartWare (Medtronic-HeartWare, Minneapolis, MN) and examine its association with device thrombosis. METHODS: Malposition was quantified based on angular deviation from a hypothetic ideal inflow cannula position in two orthogonal computed tomography imaging planes. Ideal position lies on a line from the apex to the center of the mitral valve. Positive anterior plane angulation indicates deviation toward the superior free wall; negative, toward the inferior wall. Positive lateral plane angulation indicates deviation toward the septum; negative, toward the lateral wall. Device thrombosis was assessed based on clinical criteria. RESULTS: Fifty-four HeartMate II patients and 68 HeartWare patients were analyzed. Inflow cannula deviation was significantly higher for HeartMate II than for HeartWare (anterior plane angle 36.7 ± 16.8 versus -18.7 ± 11.6 degrees, p < 0.001; lateral plane angle 23.7 ± 20.1 versus 0.2 ± 15.0 degrees, p < 0.001. Pump thrombosis occurred in 31% of HeartMate II patients and 2.9% of HeartWare patients (p < 0.001). In a multivariate model, HeartMate II and increasing inflow cannula deviation toward the septum were associated with higher thrombosis risk (odds ratio 1.35 per 10-degree increase). CONCLUSIONS: We found distinct device-dependent differences in inflow cannula positioning and thrombosis, with HeartWare showing both less malposition and less thrombosis. Malposition toward the ventricular septum may contribute to pump thrombosis through a vicious cycle of suction events, low flow, and speed reduction.

Systemic Inflammatory Response Syndrome in End-Stage Heart Failure Patients Following Continuous-Flow Left Ventricular Assist Device Implantation: Differences in Plasma Redox Status and Leukocyte Activation.

The role of oxidative stress and leukocyte activation has not been elucidated in developing systemic inflammatory response syndrome (SIRS) in heart failure (HF) patients after continuous-flow left ventricular assist device (CF-LVAD) implantation. The objective of this study was to investigate the change of plasma redox status and leukocyte activation in CF-LVAD implanted HF patients with or without SIRS. We recruited 31 CF-LVAD implanted HF patients (16 SIRS and 15 non-SIRS) and 11 healthy volunteers as the control. Pre- and postimplant blood samples were collected from the HF patients. Plasma levels of oxidized low-density lipoprotein (oxLDL), malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD) in erythrocyte, myeloperoxidase (MPO), and polymorphonuclear elastase (PMN-elastase) were measured. The HF patients had a preexisting condition of oxidative stress than healthy controls as evident from the higher oxLDL and MDA levels as well as depleted SOD and TAC. Leukocyte activation in terms of higher plasma MPO and PMN-elastase was also prominent in HF patients than controls. Persistent oxidative stress and reduced antioxidant status were found to be more belligerent in HF patients with SIRS after the implantation of CF-LVAD when compared with non-SIRS patients. Similar to oxidative stress, the activation of blood leukocyte was significantly highlighted in SIRS patients after implantation compared with non-SIRS. We identified that the plasma redox status and leukocyte activation became more prominent in CF-LVAD implanted HF patients who developed SIRS. Our findings suggest that plasma biomarkers of oxidative stress and leukocyte activation may be associated with the development of SIRS after CF-LVAD implant surgery.

Systemic Inflammatory Response Syndrome After Contentious-Flow Left Ventricular Assist Device Implantation and Change in Platelet Mitochondrial Membrane Potential.

BACKGROUND: The objective of this study was to investigate the change of platelet function and platelet mitochondrial membrane potential in contentious-flow left ventricular assist device (CF-LVAD)-implanted heart failure (HF) patients with or without systemic inflammatory response syndrome (SIRS). METHODS AND RESULTS: We recruited 31 CF-LVAD patients (16 SIRS and 15 non-SIRS) and 11 healthy volunteers as control. Pre- and post-implantation blood samples were collected. We used PFA-100 to test platelet functionality. Mitochondrial potential-sensitive dye was used to detect platelet dysfunction (mitochondrial membrane potential; ΔΨm) via flow cytometry. The percentage of depolarized-ΔΨm platelets was found to be a preexisting condition in all HF patients before CF-LVAD implantation compared with control subjects (10.3 ± 6.3% vs 2.8 ± 2.2%; P < .001). As evident from the PFA-100 test, the HF patients who developed SIRS after CF-LVAD implantation had significantly more qualitative platelet defects and thrombocytopathies compared with baseline. After implantation, the depolarized platelets in the SIRS patients increased by 2-fold compared with baseline (18.2 ± 8.4% vs 9.0 ± 6.6%; P < .01); whereas no change was noticed in the non-SIRS patients (10.9 ± 6.2% vs 11.7 ± 5.8%; P = .75). CONCLUSIONS: We identified that platelet function and mitochondrial damage were enhanced in CF-LVAD patients with SIRS. Our findings suggest that depolarization of mitochondrial membrane potential is associated with SIRS after CF-LVAD implantation surgery.

University of Maryland surgical experience with the Jarvik 2000 axial flow ventricular assist device.

BACKGROUND: The Jarvik 2000, an axial flow ventricular assist device (VAD), is currently under investigation for bridge to transplant (BTT) indications. The principal advantage of the Jarvik device is intraventricular pump placement. This eliminates the inflow cannula and pump pocket and allows for uncomplicated left ventricular implantation without sternotomy. Here we describe the evolution of our surgical implantation and explantation technique. METHODS: Data for all patients undergoing implantation of a left VAD (LVAD) (n=35) at the University of Maryland between September 2002 and September 2010 were retrospectively reviewed. Preoperative patient demographics and clinical status and operative technique and outcomes were reviewed. RESULTS: A simple technique for enclosing the pump and outflow graft greatly simplifies the explantation procedure and reduces the risk of lung adhesions and injury. Off-pump implantation reduces operative time and intraoperative red cell transfusions but carries a risk of incomplete ventricular coring, which may precipitate pump thrombosis. The benefits of the left thoracotomy approach were seen in the reduced need for intraoperative red cell transfusion and reduced total intensive care unit (ICU) stay for patients who had undergone previous sternotomy. CONCLUSIONS: The Jarvik 2000 has several distinctive features that simplify surgical management and permit flexible application in an expanded range of candidates for LVAD implantation, particularly in patients who have undergone previous sternotomy.

Clinical outcomes are similar in pulsatile and nonpulsatile left ventricular assist device recipients.

BACKGROUND: Despite concerns about the adequacy of support provided by continuous-flow left ventricular assist devices (LVADs), direct comparisons of patient characteristics and outcomes between first-generation pulsatile and second-generation nonpulsatile LVADs are absent. We hypothesized that a nonpulsatile Jarvik 2000 LVAD (Jarvik Heart, Inc, New York, NY) would result in comparable outcomes to those of similarly ill patients implanted with a pulsatile LVAD (Novacor, WorldHeart Inc, Oakland, CA; and HeartMate XVE, Thoratec, Pleasanton, CA). METHODS: We retrospectively compared common pre-LVAD clinical characteristics and indicators of heart failure severity between 13 pulsatile and 14 nonpulsatile LVAD recipients. The outcomes analyzed were either heart transplantation, if the LVAD was intended as a bridge to transplantation, or hospital discharge if the intention was destination therapy. RESULTS: There was no significant difference between groups in pre-LVAD disease severity indicators. Nonpulsatile LVAD recipients had a significantly smaller body surface area (1.9 +/- 0.2 m2 versus 2.1 +/- 0.2 m2, p = 0.04) and cardiopulmonary bypass time was also significantly shorter (61 +/- 34 minutes versus 110 +/- 49 minutes, p = 0.01). Aside from duration of initial intensive care unit stay (nonpulsatile, 10 +/- 16 days; pulsatile, 14 +/- 11 days; p = 0.02), there was no difference in post-LVAD outcomes: 10 of 14 nonpulsatile and 8 of 13 pulsatile LVAD patients achieved the combined end point (p = 0.69). CONCLUSIONS: Similarly ill congestive heart failure patients benefited equally well from either a nonpulsatile or a pulsatile LVAD. This may support an expanded role for nonpulsatile LVADs in the treatment of severe heart failure.