James W. Long

Advanced Heart Failure Treated with Continuous-Flow Left Ventricular Assist Device

BACKGROUND Patients with advanced heart failure have improved survival rates and quality of life when treated with implanted pulsatile-flow left ventricular assist devices as compared with medical therapy. New continuous-flow devices are smaller and may be more durable than the pulsatile-flow devices. METHODS In this randomized trial, we enrolled patients with advanced heart failure who were ineligible for transplantation, in a 2:1 ratio, to undergo implantation of a continuous-flow device (134 patients) or the currently approved pulsatile-flow device (66 patients). The primary composite end point was, at 2 years, survival free from disabling stroke and reoperation to repair or replace the device. Secondary end points included survival, frequency of adverse events, the quality of life, and functional capacity. RESULTS Preoperative characteristics were similar in the two treatment groups, with a median age of 64 years (range, 26 to 81), a mean left ventricular ejection fraction of 17%, and nearly 80% of patients receiving intravenous inotropic agents. The primary composite end point was achieved in more patients with continuous-flow devices than with pulsatile-flow devices (62 of 134 [46%] vs. 7 of 66 [11%]; P<0.001; hazard ratio, 0.38; 95% confidence interval, 0.27 to 0.54; P<0.001), and patients with continuous-flow devices had superior actuarial survival rates at 2 years (58% vs. 24%, P=0.008). Adverse events and device replacements were less frequent in patients with the continuous-flow device. The quality of life and functional capacity improved significantly in both groups. CONCLUSIONS Treatment with a continuous-flow left ventricular assist device in patients with advanced heart failure significantly improved the probability of survival free from stroke and device failure at 2 years as compared with a pulsatile device. Both devices significantly improved the quality of life and functional capacity. (ClinicalTrials.gov number, NCT00121485.)

Outcomes of Left Ventricular Assist Device Implantation as Destination Therapy in the Post-REMATCH Era Implications for Patient Selection

Background— The landmark Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial first demonstrated that implantation of left ventricular assist devices (LVADs) as destination therapy (DT) can provide survival superior to any known medical treatment in patients with end-stage heart failure who are ineligible for transplantation. In the present study, we describe outcomes of DT in the post-REMATCH era in the United States. Methods and Results— The present study included 280 patients who underwent HeartMate XVE LVAD implantation between November 2001 and December 2005. A preoperative risk score for in-hospital mortality after LVAD implantation was established in 222 patients with complete data. All patients were followed up until death or December 2006. The 1-year survival after LVAD implantation was 56%. The in-hospital mortality after LVAD surgery was 27%. The main causes of death included sepsis, right heart failure, and multiorgan failure. The most important determinants of in-hospital mortality were poor nutrition, hematological abnormalities, markers of end-organ or right ventricular dysfunction, and lack of inotropic support. Stratification of DT candidates into low (n=65), medium (n=111), high (n=28), and very high (n=18) risk on the basis of the risk score calculated from these predictors corresponded with 1-year survival rates of 81%, 62%, 28%, and 11%, respectively. Conclusions— Appropriate selection of candidates and timing of LVAD implantation are critical for improved outcomes of DT. Patients with advanced heart failure who are referred for DT before major complications of heart failure develop have the best chance of achieving an excellent 1-year survival with LVAD therapy.

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.)

Results of the Destination Therapy Post-Food and Drug Administration Approval Study With a Continuous Flow Left Ventricular Assist Device: A Prospective Study Using the INTERMACS Registry (Interagency Registry for Mechanically Assisted Circulatory Support)

OBJECTIVES A post-approval (PA) study for destination therapy (DT) was required by the Food and Drug Administration (FDA) to determine whether results with the HeartMate (HM) II (Thoratec, Pleasanton, California) left ventricular assist device (LVAD) in a commercial setting were comparable to results during the DT multicenter pivotal clinical trial. BACKGROUND New device technology developed in the clinical research setting requires validation in a real-world setting. METHODS The PA study was a prospective evaluation of the first 247 HM II patients identified pre-operatively as eligible for DT in the national INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) registry. Patients were enrolled from January to September 2010 at 61 U.S. centers and followed for 2 years. A historical comparison group included patients (n = 133 at 34 centers) enrolled in the primary data cohort in the DT pivotal trial (TR). Survival rates and adverse events for the PA group were obtained from the INTERMACS registry. RESULTS Baseline characteristics were similar for PA versus TR. Forty-five percent of PA patients were in INTERMACS profiles 1 to 2 and 28% were in profile 3. Adverse events in the PA group were similar or lower than those in the TR group, including improvements in device-related infection (0.22 vs. 0.47) and post-operative bleeding requiring surgery (0.09 vs. 0.23) events per patient-year. Kaplan-Meier survival at 2 years was 62% (PA group) versus 58% (TR group). PA group survival at 1 and 2 years was 82 ± 5% and 69 ± 6% for INTERMACS profiles 4 to 7 (n = 63) versus 72 ± 3% and 60 ± 4% for profiles 1 to 3 (n = 184). The median length of stay after surgery was reduced by 6 days in the PA group versus the TR group. CONCLUSIONS Results in a commercial patient care setting for the DT population supported the original pivotal clinical trial findings regarding the efficacy and risk profile of the HM II LVAD. Survival was best in patients who were not inotrope-dependent (INTERMACS profiles 4 to 7).

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.

Outcomes of a multicenter trial of the Levitronix CentriMag ventricular assist system for short-term circulatory support

OBJECTIVE The Levitronix CentriMag (Levitronix LLC, Waltham, Mass) ventricular assist system is designed for temporary left, right, or biventricular support. Advantages include ease of use, excellent reliability, and low thrombosis risk,. which may allow wider application of short-term support and improved outcomes in patients with cardiogenic shock. This multi-institutional study evaluated safety, effectiveness, and outcomes of the CentriMag in patients with cardiogenic shock. METHODS Thirty-eight patients were supported at 7 centers. Patients included 12 after cardiotomy, 14 after myocardial infarction, and 12 with right ventricular failure after implantable left ventricular assist device placement. Devices were implanted in left (n = 8), right (n = 12), or biventricular (n = 18) configuration. Support was continued until recovery, transplantation, or implantation of long-term ventricular assist device. RESULTS Mean support duration for the entire cohort (n = 38) was 13 days (1-60 days), with 47% of patients (18/38) surviving 30 days after device removal. Mean CentriMag biventricular support (n = 18) duration was 15 days (1-60 days), with 44% (8/18) surviving at 30 days. Mean CentriMag right ventricular support with a commercially available left ventricular assist device (n = 12) duration was 14 days (1-29 days), with 58% (7/12) surviving at 30 days. Complications included bleeding (21%), infection (5%), respiratory failure (3%), hemolysis (5%), and neurologic dysfunction (11%). There were no CentriMag or pump failures. CONCLUSIONS In this preliminary study, the CentriMag provided short-term support for patients with cardiogenic shock with a low incidence of device-related complications and no device failures.

Improving outcomes with long-term “destination” therapy using left ventricular assist devices

OBJECTIVE Destination therapy experience using long-term left ventricular assist devices was analyzed relative to the benchmark Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure trial to evaluate the potential for improving outcomes with this groundbreaking therapy for advanced heart failure. METHODS The largest single-center experience with destination therapy in the United States (Utah Artificial Heart Program, LDS Hospital, Salt Lake City, UT) was retrospectively analyzed. All destination therapy recipients (n = 23) presented with chronic, advanced heart failure, meeting indications for destination therapy adopted from the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure trial. All received HeartMate left ventricular assist devices (Thoratec Corp, Pleasanton, Calif), with 87% receiving an improved XVE model. Advanced practice guidelines were implemented using a multidisciplinary approach. Survivals (Kaplan-Meier, log-rank analyses) and adverse events (Poisson regression) were compared with those of the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure left ventricular assist device group (n = 68). RESULTS Survival in the destination therapy group was significantly increased (P = .007), with an overall reduction in mortality of 66%. The 2-year survival was 77% for destination therapy compared with 29% for the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure left ventricular assist device group (P < .0001). The 1-year survival was 77% for destination therapy compared with the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure left ventricular assist device rate of 52% (P = .036). Adverse events decreased by 38% (3.90 per patient-year in the destination therapy group compared with the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure left ventricular assist device rate of 6.32). Factors related to severity of illness met Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure-like criteria for both groups. CONCLUSIONS This analysis provides evidence that long-term destination therapy can be improved well beyond the pioneering experience of the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure trial. With continued evolution of devices, management, and patient selection, outcomes approaching those of heart transplantation may be possible.

Implantable centrifugal blood pump with hybrid magnetic bearings

Test methods and results of in vitro assessment of a centrifugal pump with a magnetically suspended impeller are provided. In vitro blood tests have been completed with a resulting normalized milligram index of hemolysis (NmIH) of 12.4 +/- 4.1, indicating that hemolysis is not a problem. Hydraulic characterization of the system with water has shown that a nominal pumping condition of 6 L/min at 100 mmHg was met at 2,200 rpm. Maximum clinically usable cardiac output is predicted be 10 L/min. The magnetic bearing supported impeller did not contact the housing and was shown to be stable under a variety of pumping conditions. The driving motor efficiency is 75% at the nominal condition. Finally, a description of the clinical version of the pump under development is provided.

Impact of Center Volume on Outcomes of Left Ventricular Assist Device Implantation as Destination Therapy Analysis of the Thoratec HeartMate Registry, 1998 to 2005

Background—More than 400 patients with end-stage heart failure underwent left ventricular assist device (LVAD) implantation of LVAD as destination therapy (DT) after the US Food and Drug Administration approval of DT in 2002. Because most of these patients had surgeries at hospitals that were newly accredited, we sought to examine the impact of LVAD center volume on the outcomes of DT. Methods and Results—From July 1998 through December 2005, a total of 377 patients underwent implantation of HeartMate I LVAD as DT at 68 centers in the United States. Using data from the Thoratec DT Registry, we examined the association between LVAD center volume at the time of surgery and 1-year survival with DT. Of the studied 377 DT recipients, 53% underwent device implantation at centers that performed ≤4 DT implants at the time of surgery. Center experience with DT seemed to significantly correlate with the 1-year survival (47.8% versus 67.4% in recipients of ≤4th DT versus >9th DT implant; P=0.009). However, the DT center volume was not an independent predictor of 1-year survival with DT when adjusted for the preoperative DT Risk Score, suggesting that other factors, such as improved candidate selection, may have accounted for the institutional learning curve. Conclusions—The institutional experience with DT may have a significant impact on outcomes of this therapy. Better selection of candidates, systemic approach to surgical and postoperative care, as well as the long-term medical management most likely all contribute to these improvements.

The CardioWest total artificial heart bridge to transplantation: 1993 to 1996 National Trial

BACKGROUND We performed a controlled study of a total artificial heart in bridge to transplantation. We hypothesized that the CardioWest total artificial heart used in a selected population of decompensating cardiac transplantation candidates would result in improved survival compared with matched controls. METHODS The CardioWest trial started in 1993 in six United States institutions under an investigational device exemption from the Food and Drug Administration. Four centers contributed 27 implant and 18 matched retrospective control patients. RESULTS Of the implant patients, 25 (93%) received a transplant, 24 (89% of the total, 96% of those transplanted) were discharged and are currently surviving. In the control group, 10 patients died awaiting transplantation, 8 received a transplant, and 7 were discharged with 6 surviving (p = 0.00001). All adverse events were documented with respect to time. Thirteen serious adverse events occurred, 11 of which occurred in the 2 patients that died during implant. CONCLUSIONS In a selected group of patients with endstage heart disease, use of the CardioWest total artificial heart is lifesaving. When compared with the series of matched retrospective controls, a significant improvement in survival was found in the CardioWest implant group.