Christopher T. Salerno

A Fully Magnetically Levitated Circulatory Pump for Advanced Heart Failure

Background Continuous‐flow left ventricular assist systems increase the rate of survival among patients with advanced heart failure but are associated with the development of pump thrombosis. We investigated the effects of a new magnetically levitated centrifugal continuous‐flow pump that was engineered to avert thrombosis. Methods We randomly assigned patients with advanced heart failure to receive either the new centrifugal continuous‐flow pump or a commercially available axial continuous‐flow pump. Patients could be enrolled irrespective of the intended goal of pump support (bridge to transplantation or destination therapy). The primary end point was a composite of survival free of disabling stroke (with disabling stroke indicated by a modified Rankin score >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove the device at 6 months after implantation. The trial was powered for noninferiority testing of the primary end point (noninferiority margin, ‐10 percentage points). Results Of 294 patients, 152 were assigned to the centrifugal‐flow pump group and 142 to the axial‐flow pump group. In the intention‐to‐treat population, the primary end point occurred in 131 patients (86.2%) in the centrifugal‐flow pump group and in 109 (76.8%) in the axial‐flow pump group (absolute difference, 9.4 percentage points; 95% lower confidence boundary, ‐2.1 [P<0.001 for noninferiority]; hazard ratio, 0.55; 95% confidence interval [CI], 0.32 to 0.95 [two‐tailed P=0.04 for superiority]). There were no significant between‐group differences in the rates of death or disabling stroke, but reoperation for pump malfunction was less frequent in the centrifugal‐flow pump group than in the axial‐flow pump group (1 [0.7%] vs. 11 [7.7%]; hazard ratio, 0.08; 95% CI, 0.01 to 0.60; P=0.002). Suspected or confirmed pump thrombosis occurred in no patients in the centrifugal‐flow pump group and in 14 patients (10.1%) in the axial‐flow pump group. Conclusions Among patients with advanced heart failure, implantation of a fully magnetically levitated centrifugal‐flow pump was associated with better outcomes at 6 months than was implantation of an axial‐flow pump, primarily because of the lower rate of reoperation for pump malfunction. (Funded by St. Jude Medical; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755.)

Algorithm for the diagnosis and management of suspected pump thrombus

Pump thrombosis is a dreaded complication of long-term implantable ventricular assist devices. No guidance exists regarding the diagnosis and management of this entity despite its significant morbidity. After considerable thought and deliberation, a group of leading investigators in the field of mechanical support propose an algorithm for the diagnosis and management of this vexing entity based on clinical symptoms and serologic and imaging studies.

Reversal of diabetes in non-immunosuppressed rhesus macaques by intraportal porcine islet xenografts precedes acute cellular rejection

Abstract:  Background:  The functional response and immunobiology of primarily non‐vascularized islet cell xenografts remain poorly defined in non‐human primates.

Surgical Therapy for Pulmonary Aspergillosis in Immunocompromised Patients

BACKGROUND Medical management for invasive pulmonary aspergillosis (IPA) is often unsatisfactory. Antifungal therapy may be unable to eradicate IPA in the immunocompromised or neutropenic patient. METHODS We retrospectively reviewed the surgical management of IPA in 13 immunocompromised patients at our institution. Twelve patients underwent perioperative bone marrow transplantation (4 autologous, 8 allogenic). All 13 patients received antifungal therapy. Eleven patients were neutropenic at the time of operation. RESULTS The mean interval from diagnosis of aspergillosis to operation was 42 days (range, 3 to 135 days). Eighteen operations were performed on the 13 patients. Seven patients had resections from multiple pulmonary sites, whereas 6 had a single lesion resected. The average lesion resected was 3.7 cm in greatest diameter (range, 1 to 9 cm). After a mean follow-up of 21 months (range, 0 to 9 years), 3 patients (23%) are alive with no evidence of aspergillosis, 6 patients (46%) died without evidence of aspergillosis, and 4 patients (31%) died secondary to aspergillus infection. All 4 patients who died of aspergillus infection received an allogenic bone marrow transplantation. Two patients with direct extrapulmonic extension of IPA at time of operation died of recurrent aspergillus infections. Three of 4 patients who died of aspergillus infection had an absolute neutrophil count less than 1,300 cells/microL at time of operation. The mean absolute neutrophil count of the patients who cleared the aspergillus infection was 5,538 cells/microL. The mean survival of allogenic bone marrow transplant recipients was 5.2 months, and for recipients of autografts was 51.4 months. CONCLUSIONS In this series, surgical resection of IPA cleared the aspergillus infection in 69% of the patients. Neutropenia, extrapulmonic extension of IPA, and allogenic bone marrow transplantation may predict a worse prognosis. Surgical resection of IPA in immunocompromised patients is an effective form of therapy in a properly selected patient population.

Adjuvant treatment of refractory lung transplant rejection with extracorporeal photopheresis

BACKGROUND Extracorporeal photopheresis is an immunomodulatory technique in which a patients leukocytes are exposed to ultraviolet-A light after pretreatment with 8-methoxypsoralen (methoxsalen). There have been few reports describing the use of extracorporeal photopheresis in lung transplant recipients. METHODS We reviewed our experience using extracorporeal photopheresis in 8 lung transplant recipients since 1992. All 8 patients had progressively decreasing graft function and 7 were in bronchiolitis obliterans syndrome grade 3 before the initiation of photopheresis. One patient had undergone a second transplant operation for obliterative bronchiolitis. Two patients had a pretransplantation diagnosis of chronic obstructive pulmonary disease, 1 alpha1-antitrypsin deficiency, 1 cystic fibrosis, 1 bronchiectasis, 1 idiopathic pulmonary fibrosis, and 2 primary pulmonary hypertension. Before refractory rejection developed, all patients had been treated with 3-drug immunosuppression and anti-T-cell therapy. The median time from transplantation to the start of extracorporeal photopheresis was 16.5 months and the median number of treatments was 6. RESULTS The condition of 5 of 8 patients subjectively improved after extracorporeal photopheresis therapy. In these 5 patients photopheresis was associated with stabilization of the forced expiratory volume in 1 second. In 2 patients there was histologic reversal of rejection after photopheresis. With a median follow-up of 36 months, 7 patients are alive and well. Three patients required retransplantation at a median of 21 months after completion of the treatments. Four patients have remained in stable condition after photopheresis. There were no complications related to extracorporeal photopheresis. CONCLUSION We believe that this treatment is a safe option for patients with refractory lung allograft rejection when increased immunosuppression is contraindicated or ineffective.

The HVAD Left Ventricular Assist Device: Risk Factors for Neurological Events and Risk Mitigation Strategies.

OBJECTIVES The purpose of this study was to determine the risk factors for ischemic in hemorrhage cerebrovascular events in patients supported by the HeartWare ventricular assist device (HVAD). BACKGROUND Patients supported with left ventricular assist devices are at risk for both ischemic and hemorrhagic cerebrovascular events. METHODS Patients undergoing implantation with a HVAD as part of the bridge-to-transplant trial and subsequent continued access protocol were included. Neurological events (ischemic cerebrovascular accidents [ICVAs] and hemorrhagic cerebrovascular accidents [HCVAs]) were assessed, and the risk factors for these events were evaluated in a multivariable model. RESULTS A total of 382 patients were included: 140 bridge-to-transplant patients from the ADVANCE (Evaluation of the HeartWare Left Ventricular Assist Device for the Treatment of Advanced Heart Failure) clinical trial and 242 patients from the continued access protocol. Patients had a mean age of 53.2 years; 71.2% were male, and 68.1% were white. Thirty-eight percent had ischemic heart disease, and the mean duration of support was 422.7 days. The overall prevalence of ICVA was 6.8% (26 of 382); for HCVA, it was 8.4% (32 of 382). Pump design modifications and a protocol-driven change in the antiplatelet therapy reduced the prevalence of ICVA from 6.3% (17 of 272) to 2.7% (3 of 110; p = 0.21) but had a negligible effect on the prevalence of HVCA (8.8% [24 of 272] vs. 6.4% [7 of 110]; p = 0.69). Multivariable predictors of ICVA were aspirin ≤81 mg and atrial fibrillation; predictors of HCVA were mean arterial pressure >90 mm Hg, aspirin ≤81 mg, and an international normalized ratio >3.0. Eight of the 30 participating sites had established improved blood pressure management (IBPM) protocols. Although the prevalence of ICVA for those with and without IBPM protocols was similar (5.3% [6 of 114] vs. 5.2% [14 of 268]; p = 0.99), those with IBPM protocols had a significantly lower prevalence of HCVA (1.8% [2 of 114] vs. 10.8% [29 of 268]; p = 0.0078). CONCLUSIONS Anticoagulation, antiplatelet therapy, and blood pressure management affected the prevalence of cerebrovascular events after implantation of the HVAD. Attention to these clinical parameters can have a substantial impact on the occurrence of serious neurological events. (Evaluation of the HeartWare Left Ventricular Assist Device for the Treatment of Advanced Heart Failure [ADVANCE]; NCT00751972).

Impact of concurrent surgical valve procedures in patients receiving continuous-flow devices

BACKGROUND Preexisting valve pathology is common in patients with end-stage heart failure undergoing left ventricular assist device (LVAD) placement. The indications and subsequent benefits of performing valvular procedures in these patients are unclear. The objective of this study was to determine the impact of performing concurrent surgical valve procedures in a large cohort of patients receiving LVADs. METHODS One thousand one hundred six patients received the HeartMate II (HMII) LVAD in the bridge to transplant (n = 470) and destination therapy (n = 636) clinical trials. Of these, 374 patients (34%) had concurrent cardiac surgery procedures as follows: 242 patients (21%) with 281 concurrent valve procedures (VP) (aortic 80, mitral 45, and tricuspid 156), and 641 patients had only HMII LVAD. The focus of this study was to determine the clinical outcomes of patients undergoing HMII + VP compared with those who received HMII alone. RESULTS Patients undergoing HMII + VP were significantly older, had higher blood urea nitrogen levels and central venous pressure, and decreased right ventricular stroke work index; intraoperatively, the median cardiopulmonary bypass times were also longer. The unadjusted 30-day mortality was significantly higher in patients undergoing HMII + VP (10.3% vs 4.8% for LVAD alone, P = .005). Subgroup analysis of individual VPs showed that higher mortality occurred in patients with HMII plus 2 or more VPs (13.5%, P = .04) followed by trends for increased mortality with HMII plus mitral alone (11.5%, P = NS), HMII plus aortic alone (10.9%, P = NS), and HMII plus tricuspid (8.9%, P = NS) procedures. Of these various groups, only patients undergoing HMII + isolated aortic VP (P = .001) and HMII + multiple VPs (P = .046) had significantly worse long-term survival compared with patients undergoing HMII alone. Right heart failure and right ventricular assist device use was increased in patients undergoing VPs, but there was no difference in the incidence of bleeding or stroke. CONCLUSIONS Patients frequently require concurrent VPs at the time of LVAD placement; these patients are sicker and have higher early mortality. Furthermore, right ventricular dysfunction is increased in these patients. Further studies to develop selection criteria for concurrent valve interventions are important to further improve clinical outcomes.

A recombinant soluble chimeric complement inhibitor composed of human CD46 and CD55 reduces acute cardiac tissue injury in models of pig-to-human heart transplantation

BACKGROUND Inasmuch as complement plays a critical role in many pathological processes and in xenograft rejection, efficient complement inhibitors are of great interest. Because the membrane-associated complement inhibitors are very effective, recombinant soluble molecules have been generated. METHODS We tested the efficacy of complement activation blocker-2 (CAB-2), a recombinant soluble chimeric protein derived from human decay accelerating factor (DAF, CD55) and membrane cofactor protein (MCP, CD46), in two models of pig-to-human xenotransplantation in which tissue injury is complement mediated. The in vitro model consisted of porcine aortic endothelial cells and human serum, and the ex vivo model consisted of a porcine heart perfused with human blood. RESULTS In vitro, addition of CAB-2 to serum inhibited cytotoxicity and the deposition of C4b and iC3b on the endothelial cells. Ex vivo, addition of CAB-2 to human blood prolonged organ survival from 17.3 +/- 6.4 min in controls to 108 +/- 55.6 min with 910 nM (100 microg/ml) CAB-2 and 219.8 +/- 62.7 min with 1820 nM (200 microg/ml) CAB-2. CAB-2 also retarded the onset of increased coronary vascular resistance. The complement activity of the perfusate was reduced by CAB-2, as was the generation of C3a and SC5b-9. The myocardial tissues had similar deposition of IgG, IgM, and Clq; however, CAB-2 reduced the deposition of C3, C4, and C9. Hearts surviving >240 min demonstrated trace to no deposition of C9 and normal histologic architecture. CONCLUSION These results indicate that CAB-2 can function as an inhibitor of complement activation and markedly reduce tissue injury in models of pig-to-human xenotransplantation and thus may represent a useful therapeutic agent for xenotransplantation and other complement-mediated conditions.

Two-Year Outcomes with a Magnetically Levitated Cardiac Pump in Heart Failure

Background In an early analysis of this trial, use of a magnetically levitated centrifugal continuous‐flow circulatory pump was found to improve clinical outcomes, as compared with a mechanical‐bearing axial continuous‐flow pump, at 6 months in patients with advanced heart failure. Methods In a randomized noninferiority and superiority trial, we compared the centrifugal‐flow pump with the axial‐flow pump in patients with advanced heart failure, irrespective of the intended goal of support (bridge to transplantation or destination therapy). The composite primary end point was survival at 2 years free of disabling stroke (with disabling stroke indicated by a modified Rankin score of >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove a malfunctioning device. The noninferiority margin for the risk difference (centrifugal‐flow pump group minus axial‐flow pump group) was ‐10 percentage points. Results Of 366 patients, 190 were assigned to the centrifugal‐flow pump group and 176 to the axial‐flow pump group. In the intention‐to‐treat population, the primary end point occurred in 151 patients (79.5%) in the centrifugal‐flow pump group, as compared with 106 (60.2%) in the axial‐flow pump group (absolute difference, 19.2 percentage points; 95% lower confidence boundary, 9.8 percentage points [P<0.001 for noninferiority]; hazard ratio, 0.46; 95% confidence interval [CI], 0.31 to 0.69 [P<0.001 for superiority]). Reoperation for pump malfunction was less frequent in the centrifugal‐flow pump group than in the axial‐flow pump group (3 patients [1.6%] vs. 30 patients [17.0%]; hazard ratio, 0.08; 95% CI, 0.03 to 0.27; P<0.001). The rates of death and disabling stroke were similar in the two groups, but the overall rate of stroke was lower in the centrifugal‐flow pump group than in the axial‐flow pump group (10.1% vs. 19.2%; hazard ratio, 0.47; 95% CI, 0.27 to 0.84, P=0.02). Conclusions In patients with advanced heart failure, a fully magnetically levitated centrifugal‐flow pump was superior to a mechanical‐bearing axial‐flow pump with regard to survival free of disabling stroke or reoperation to replace or remove a malfunctioning device. (Funded by Abbott; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755.)

Hemocompatibility-related Outcomes in the Momentum 3 Trial at 6 Months: A Randomized Controlled Study of a Fully Magnetically Levitated Pump in Advanced Heart Failure

Background: The HeartMate 3 (HM3) Left Ventricular Assist System (LVAS) (Abbott) is a centrifugal, fully magnetically levitated, continuous-flow blood pump engineered to enhance hemocompatibility and reduce shear stress on blood components. The MOMENTUM 3 trial (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3) compares the HM3 LVAS with the HeartMate II (HMII) LVAS (Abbott) in advanced heart failure refractory to medical management, irrespective of therapeutic intention (bridge to transplant versus destination therapy). This investigation reported its primary outcome in the short-term cohort (n=294; 6-month follow-up), demonstrating superiority of the HM3 for the trial primary end point (survival free of a disabling stroke or reoperation to replace the pump for malfunction), driven by a reduced need for reoperations. The aim of this analysis was to evaluate the aggregate of hemocompatibility-related clinical adverse events (HRAEs) between the 2 LVAS. Methods: We conducted a secondary end point evaluation of HRAE (survival free of any nonsurgical bleeding, thromboembolic event, pump thrombosis, or neurological event) in the short-term cohort (as-treated cohort n=289) at 6 months. The net burden of HRAE was also assessed by using a previously described hemocompatibility score, which uses 4 escalating tiers of hierarchal severity to derive a total score for events encountered during the entire follow-up experience for each patient. Results: In 289 patients in the as-treated group (151 the HM3 and 138 the HMII), survival free of any HRAE was achieved in 69% of the HM3 group and in 55% of the HMII group (hazard ratio, 0.62; confidence interval, 0.42–0.91; P=0.012). Using the hemocompatibility score, the HM3 group demonstrated less pump thrombosis requiring reoperation (0 versus 36 points, P<0.001) or medically managed pump thrombosis (0 versus 5 points, P=0.02), and fewer nondisabling strokes (6 versus 24 points, P=0.026) than the control HMII LVAS. The net hemocompatibility score in the HM3 in comparison with the HMII patients was 101 (0.67±1.50 points/patient) versus 137 (0.99±1.79 points/patient) (odds ratio, 0.64; confidence interval, 0.39–1.03; P=0.065). Conclusions: In this secondary analysis of the MOMENTUM 3 trial, the HM3 LVAS demonstrated greater freedom from HRAEs in comparison with the HMII LVAS at 6 months. Clinical Trial Registration: URL: http://clinicaltrials.gov. Unique identifier: NCT02224755.