Continuous-Flow Left Ventricular Assist Device Explantation After More Than 5 Years of Circulatory Support and Ventricular Reconditioning.

Continuous-flow left ventricular assist devices have proved to be effective, durable, life-saving tools in patients with end-stage heart failure. However, because of the risks associated with mechanical circulatory support (including stroke, infection, gastrointestinal bleeding, and device malfunction), the optimal goal of device therapy is myocardial recovery and device removal. Ventricular reconditioning and pump explantation after continuous-flow support have been reported; however, little is known about variables that govern the pace and degree of myocardial response in patients who experience such recovery. We describe our long-term pump-weaning strategy for a 25-year-old man who had a continuous-flow device implanted and then needed more than 5 years of support from it before developing cardiac reserve sufficient to enable pump explantation. To our knowledge, this is the longest period of uninterrupted continuous-flow device support to end in successful pump deactivation and a return to medical therapy. This case highlights the importance of actively and persistently pursuing a device-weaning strategy in all patients who need left ventricular assist device therapy.

Tissue Valve Degeneration and Mechanical Valve Failure.

PURPOSE OF REVIEW: The management of valvular heart disease has been dramatically influenced by recent evolutions in biomedical technology and surgical practice. With an aging population worldwide and accompanying increase in the prevalence of surgical valve disease, an understanding of prosthetic valve behavior and durability is essential for proper patient selection and management. This report offers an overview of the definitions, mechanisms, management, and clinical impact of structural valve degeneration and failure. RECENT FINDINGS: Published literature has employed variable definitions and outcome measures, complicating our understanding of bioprosthetic valve behavior and function. The pathophysiology leading to structural valve degeneration is multifactorial and involves mechanical, hematologic, and immunologic elements. Technological advancements have resulted in improved valve performance and new strategies to mitigate the risks of degeneration. While mechanical valves have demonstrated negligible durability concerns, the benefits of bioprosthetic valves must be weighed against their potential for structural degeneration and subsequent reintervention. Valve selection should involve patient-specific deliberation, and guidelines have been established to help guide risk reduction strategies. Surgical valve replacement remains the standard of care for prosthetic valve failure, but emerging technology offers the potential to slow the development of structural degeneration and transcatheter valve-in-valve options are being increasingly explored.

Long-Term Continuous-Flow Biventricular Support in a 63-Year-Old Woman.

We describe the successful use of long-term biventricular continuous-flow mechanical circulatory support as a bridge to transplantation in a small-framed 63-year-old woman with long-standing nonischemic cardiomyopathy. After placement of a left-sided HeartWare HVAD, persistent right-sided heart failure necessitated implantation of a second HeartWare device for long-term right ventricular support. After 262 days, the patient underwent successful orthotopic heart transplantation and was discharged from the hospital. This report indicates the feasibility of biventricular device support in older patients of relatively small stature, and our results may encourage others to consider this therapy in similar patient populations.

Tolerance of Sustained Ventricular Fibrillation During Continuous-Flow Left Ventricular Assist Device Support.

The widespread use of continuous-flow left ventricular assist devices for mechanical circulatory support has shown that long-term hemodynamic support is possible, even when a clinical "pulse" cannot be detected. We present the incidental discovery of ventricular fibrillation in 6 alert, hemodynamically stable patients supported only by a continuous-flow device (HeartMate II, n=5; Jarvik 2000, n=1). Ventricular fibrillation was found in 3 patients during routine outpatient follow-up visits and in 3 awaiting discharge from the hospital after device placement. Diagnosis was confirmed by electrocardiographic and echocardiographic studies. The average duration of mechanical circulatory support before ventricular fibrillation occurred was 221 ± 362 days (range, 5-864 d). All patients were conscious and ambulatory at the time of the arrhythmia. Three patients reported symptoms-primarily fatigue, nausea, and exertional dyspnea-that prompted evaluation. Serum chemistry analysis of blood drawn immediately after diagnosis showed no changes that suggested end-organ dysfunction. Three patients died of unrelated complications an average of 3.9 yr (range, 360-2,270 d) after the event. Two of the remaining 3 patients eventually underwent successful pump explantation, and one is on ongoing support. Our experience shows that it is possible for patients with continuous-flow left ventricular assist devices to remain hemodynamically stable while in ventricular fibrillation. Additional investigation is needed to determine whether defibrillator settings for these patients should be adjusted to limit delivery of shock therapy.

Impact of concomitant mitral valve repair for severe mitral regurgitation at the time of continuous-flow left ventricular assist device insertion.

OBJECTIVES: Mitral regurgitation (MR) is common in patients with end-stage heart failure. We assessed the effect of performing concomitant mitral valve repair during continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with severe preoperative MR. METHODS: We performed a single-centre, retrospective review of all patients who underwent CF-LVAD implantation between December 1999 and December 2013 (n = 469). Patients with severe preoperative MR (n = 78) were identified and then stratified according to whether they underwent concomitant valve repair. Univariate and survival analyses were performed, and multivariable regression was used to determine predictors of survival. RESULTS: Of the 78 patients with severe MR, 21 underwent valve repair at the time of CF-LVAD implantation (repair group) and 57 did not (non-repair group). A comparison of the 2 groups showed significant differences between groups: INTERMACS I 16.985 vs 9.52%, (P = 0.039), cardiopulmonary bypass time 82.09 vs 109.4 min (P = 0.0042) and the use of HeartMate II 63.16 vs 100% (P = 0.001). Survival analysis suggested trends towards improved survival and a lower incidence of heart failure-related readmissions in the repair group. Multivariable regression analysis showed no significant independent predictors of survival (mitral valve repair: odds ratio 0.4, 95% confidence interval 0.8-1.5; P = 0.2). CONCLUSIONS: Despite the lack of statistical significance, trends towards improved survival and a lower incidence of heart failure events suggest that mitral valve repair may be beneficial in patients undergoing CF-LVAD implantation. Given the known relationship between severe MR and mortality, further study is encouraged to confirm the value of mitral valve repair in these patients.

Nonidentical Continuous-Flow Devices For Biventricular Support.

Although biventricular heart failure has been successfully managed with dual continuous-flow ventricular assist devices, the long-term use of 2 mechanically dissimilar pumps has traditionally been discouraged. We present the case of a 52-year-old man whose treatment with a HeartMate II left ventricular assist device was complicated by right ventricular failure, necessitating the implantation of a long-term right ventricular assist device. A HeartWare left ventricular assist device was placed along the right ventricular base to avoid interference with the HeartMate II housing. The patient was discharged from the hospital after routine postoperative care and dual-device training. This case shows that, despite logistical complexities, nonidentical continuous-flow device pairings can successfully provide long-term biventricular support.

Through the Looking Glass: Real-Time Video Using 'Smart' Technology Provides Enhanced Intraoperative Logistics.

INTRODUCTION: In the setting of increasingly complex medical therapies and limited physician resources, the recent emergence of 'smart' technology offers tremendous potential for improved logistics, efficiency, and communication between medical team members. In an effort to harness these capabilities, we sought to evaluate the utility of this technology in surgical practice through the employment of a wearable camera device during cardiothoracic organ recovery. METHODS: A single procurement surgeon was trained for use of an Explorer Edition Google Glass (Google Inc., Mountain View, CA) during the recovery process. Live video feed of each procedure was securely broadcast to allow for members of the home transplant team to remotely participate in organ assessment. Primary outcomes involved demonstration of technological feasibility and validation of quality assurance through group assessment. RESULTS: The device was employed for the recovery of four organs: a right single lung, a left single lung, and two bilateral lung harvests. Live video of the visualization process was remotely accessed by the home transplant team, and supplemented final verification of organ quality. In each case, the organs were accepted for transplant without disruption of standard procurement protocols. Media files generated during the procedures were stored in a secure drive for future documentation, evaluation, and education purposes without preservation of patient identifiers. CONCLUSIONS: Live video streaming can improve quality assurance measures by allowing off-site members of the transplant team to participate in the final assessment of donor organ quality. While further studies are needed, this project suggests that the application of mobile 'smart' technology offers not just immediate value, but the potential to transform our approach to the practice of medicine.

Surgical approach to continuous-flow left ventricular assist device explantation: A comparison of outcomes.

OBJECTIVE: Ventricular reconditioning and device weaning in select patients with continuous-flow left ventricular assist devices (CF LVADs) has been shown to be feasible. However, little is known regarding the outcomes associated with different surgical methods of device removal. We examined the effect of surgical explantation approach on early and late outcomes. METHODS: We retrospectively reviewed data from all patients who underwent successful ventricular weaning and CF LVAD explantation at our center. Patients were stratified by surgical approach. Descriptive univariate statistics, multivariate regression, and survival analyses were performed. Patients were censored by transplant, device reimplantation, or end of follow-up. RESULTS: Twenty-seven patients were identified who underwent successful removal of a CF LVAD (25 HeartMate II, 2 HeartWare) after 532 ± 424 days of support (range, 42-1937 days). Four approaches were used that vary primarily in the degree of retained pump material: complete pump removal with plug ventriculotomy closure (n = 13; 48%), pump housing explant with ligation of the inflow and outflow grafts (n = 7; 26%), ligation of the outflow graft and driveline transection (n = 5; 19%), and driveline transection alone (n = 2; 7%). Mean overall postexplant survival was 1286 ± 947 days (range, 143-3072 days). Overall time-to-event and survival analyses showed no significant association between surgical approach and postoperative length of stay (P = .7), stroke (P = .12), reoperation (P = .4), or survival (P = .12). CONCLUSIONS: For patients who receive device therapy, pump deactivation and removal represents a favorable outcome. All methods are feasible and produce similar early and late survival and clinical outcomes.

Ventricular reconditioning and pump explantation in patients supported by continuous-flow left ventricular assist devices.

BACKGROUND: The potential for myocardial reconditioning and device explantation after long-term continuous-flow left ventricular assist device (LVAD) support presents an opportunity to delay or avoid transplantation in select patients. METHODS: Thirty of 657 patients with end-stage heart failure supported with continuous-flow LVADs were assessed for device explantation. Each patient underwent an individualized process of weaning focused on principles of ventricular unloading, gradual reconditioning, and transition to medical therapy. RESULTS: After varying reconditioning periods, 27 patients (16 men, 11 women; age, 39 ± 12 years) underwent LVAD explant, and 3 patients (2 men, 1 woman; age, 22 ± 6 years) were evaluated for explantation but could not be weaned. The duration of LVAD support was 533 ± 424 days (range, 42-1,937 days) for the explant cohort and 1,097 ± 424 days (range, 643-1,483) for the non-explant cohort. The LV end-diastolic dimension, LV ejection fraction, systolic pulmonary artery pressure, cardiac output, and cardiac index in the explant cohort were significantly improved at explantation (all, p < 0.05). Two late deaths occurred after LVAD explantation despite satisfactory native cardiac function, and 1 patient required resumption of LVAD support 2.7 years after device removal. The remaining explant patients remain in New York Heart Association classes I to II with medical management alone (mean survival post-explant, 1,172 ± 948 days). The 3 candidates who could not be weaned ultimately underwent transplantation. CONCLUSIONS: The potential for recovery of native LV function after long-term continuous-flow LVAD support should encourage a more aggressive approach to ventricular reconditioning with the goal of device explantation and a return to medical management, particularly in young patients with dilated cardiomyopathy.

Mice lacking the signaling molecule CalDAG-GEFI represent a model for leukocyte adhesion deficiency type III.

Single gene mutations in beta integrins can account for functional defects of individual cells of the hematopoietic system. In humans, mutations in beta(2) integrin lead to leukocyte adhesion deficiency (LAD) syndrome and mutations in beta(3) integrin cause the bleeding disorder Glanzmann thrombasthenia. However, multiple defects in blood cells involving various beta integrins (beta(1), beta(2), and beta(3)) occur simultaneously in patients with the recently described LAD type III (LAD-III). Here we show that the product of a single gene, Ca(2+) and diacylglycerol-regulated guanine nucleotide exchange factor I (CalDAG-GEFI), controlled the activation of all 3 integrins in the hematopoietic system. Neutrophils from CalDAG-GEFI(-/-) mice exhibited strong defects in Rap1 and beta(1) and beta(2) integrin activation while maintaining normal calcium flux, degranulation, and ROS generation. Neutrophils from CalDAG-GEFI-deficient mice failed to adhere firmly to stimulated venules and to migrate into sites of inflammation. Furthermore, CalDAG-GEFI regulated the activation of beta(1) and beta(3) integrins in platelets, and CalDAG-GEFI deficiency caused complete inhibition of arterial thrombus formation in mice. Thus, mice engineered to lack CalDAG-GEFI have a combination of defects in leukocyte and platelet functions similar to that of LAD-III patients.