Douglas A. Horstmanshof

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.

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.)

Successful percutaneous management of acute left ventricular assist device stoppage.

The HeartMate II left ventricular assist device (LVAD) is a small axial-flow next-generation pump. Acute stoppage of this device is a potentially lethal complication. As these devices proliferate, many patients will be in areas remote to their implant center. Therefore, percutaneous stabilization of these patients before definitive surgical replacement could be potentially life saving. We present two cases of acute LVAD stoppage managed successfully using percutaneous means.

Factors Related to Pump Thrombosis With the Heartmate II Left Ventricular Assist Device.

Recent reports suggested that HeartMate II (HMII) thrombosis rates may be higher in implants after 2011. We characterize events at HMII centers (>100 HMII implants) whose device thrombosis rates are equivalent or lower than reported by INTERMACS.

Effects of gamma radiation on a ventricular assist device and its percutaneous lead components.

A patient supported by a left ventricular assist device (LVAD) presented with an abdominal tumor requiring consolidative radiation therapy. To assess the effects of radiation therapy on the operation of the ventricular assist device (VAD) system and assure that the treatment would be safe for the patient with regard to the operation of the VAD system, sample equipment was irradiated and then tested for functionality. Changes in the mechanical properties of components of the percutaneous lead were measured. After testing, it was concluded that radiation therapy would not impede the operation of the pump or produce deleterious alterations of mechanical properties of the various system components. The patient underwent radiation therapy with a total dose of 2,000 cGy without evident complications. There were no observed effects on the LVAD operation nor any indication of alarms or malfunctions. Subsequently, the patient recovered adequate cardiac function for explant of the LVAD and the recovered components were also analyzed confirming the absence of alterations in material properties that would endanger patient safety.

Postimplant left ventricular assist device fit analysis using three-dimensional reconstruction.

Left ventricular assist devices (LVADs) are blood pumps that augment the function of the failing heart to improve perfusion, resulting in improved survival. For LVADs to effectively unload the left ventricle, the inflow cannula (IC) should be unobstructed and ideally aligned with the heart’s mitral valve (MV). We examined IC orientation deviation from a hypothesized conventional angle (45° right-posterior) and the approximate angle for direct IC-MV alignment in many patients. Three-dimensional anatomic models were created from computed tomography scans for 24 LVAD-implanted patients, and angles were measured between the IC and the apical z-axis in both the coronal and the sagittal planes. Common surgical IC angulation was found to be 22 ± 15° rightward and 21 ± 12° posterior from the apical z-axis; 38% (n = 9) of patients fell in this range. Direct IC-MV angulation was found to be 34 ± 8° rightward and 15 ± 7° posterior; only 8% (n = 2) of patients fell in this range. Rightward deviation toward ventricular septal wall and anterior deviation toward LV anterior freewall are associated with mortalities more so than leftward and posterior deviation. In conclusion, anatomic reconstruction may be a useful preoperative tool to obtain general population and patient-specific alignment for optimal LVAD implantation.

Left ventricular assist devices versus medical management in ambulatory heart failure patients: An analysis of INTERMACS Profiles 4 and 5 to 7 from the ROADMAP study

BACKGROUND The ROADMAP study showed survival with improved functional status was better with left ventricular assist device (LVAD) therapy compared with optimal medical management (OMM) in ambulatory, non-inotrope-dependent (INTERMACS [IM] Profile 4 to 7) patients. To study more balanced cohorts and better define which patients may benefit from implantation of an LVAD, we re-evaluated the patients enrolled in ROADMAP when stratified by INTERMACS profile (Profile 4 and Profiles 5 to 7). METHODS The primary end-point (survival on original therapy with improvement in 6-minute walk distance ≥75 meters at 1 year), actuarial survival, adverse events (AEs) and health-related quality of life (HRQoL) were evaluated. RESULTS For INTERMACS Profile 4 (IM4), more LVAD patients met the primary end-point compared with OMM patients (40% vs 15%; odds ratio = 3.9 [1.2 to 12.7], p = 0.024), but there was no statistically significant difference for INTERMACS Profiles IM 5 to 7 (IM5-7). Event-free survival on original therapy at 2 years was greater for LVAD than for OMM patients in both IM4 (67% vs 28%; p < 0.001) and IM5-7 (76% vs 49%; p = 0.025) profile groups. Composite end-points of survival on original therapy with improved HRQoL or depression were better with LVAD than OMM in IM4, but not IM5-7. AEs trended higher in LVAD compared with OMM patients in both profile groups. Rehospitalization rates for LVAD vs OMM were similar between treatment arms in IM4 (82% vs 86%; p = 0.780), but were higher for LVAD in IM5-7 (93% vs 71%; p = 0.016). CONCLUSIONS LVAD patients in IM4, but not IM5-7, are more likely to meet the primary end-point and have improvements in HRQoL and depression compared with OMM, even with AEs generally being more frequent. LVAD therapy with current technology may be beneficial in select IM4 patients, but can be deferred for most IM5-7 patients, who should be followed closely due to the high frequency of treatment failures.

A Multisite Randomized Controlled Trial of a Patient-Centered Ventricular Assist Device Decision Aid (VADDA Trial)

BACKGROUND Studies indicate that decision making and informed consent among patients considering left ventricular assist device (LVAD) support for advanced heart failure could be improved. In the VADDA (Ventricular Assist Device Decision Aid) trial, we tested a patient-centered decision aid (DA) to enhance the quality of decision making about LVAD therapy. METHODS After an extensive user-centered design process, we conducted a multisite randomized trial of the DA compared with standard education (SE) among inpatients considering LVAD treatment for advanced heart failure The main outcome was LVAD knowledge at 1 week and 1 month after administration of the DA versus the SE, according to a validated scale. Secondary measures included prespecified quality decision making measures recommended by the International Patient Decision Aid Standards collaboration. RESULTS Of 105 eligible patients, 98 consented and were randomly assigned to the DA and SE arms. Patients receiving the VADDA exhibited significantly greater LVAD knowledge than the SE group at 1 week of follow-up (P = .01) but not at 1 month (P = .47). No differences were found between DA and SE patients in rates of acceptance versus decline of LVAD treatment (85% vs 78%; P = .74). Recipients in the DA arm reported greater satisfaction with life after implantation compared with nonrecipients (28 vs 23 out of 30; P = .008), although both arms reported high satisfaction. Patients rated the DA high in acceptability and usability. CONCLUSIONS The VADDA enhances LVAD knowledge, particularly in the short term (1 week) during the peak period of decision making. The DA does not encourage decision direction and reflects patient, caregiver, and physician preferences for content and format. CLINICAL TRIAL REGISTRATION https://clinicaltrials.gov/ct2/show/NCT02248974. The trial is registered with clinicaltrials.gov (NCT02248974).