Ulrich P. Jorde

Results of the Post-U.S. Food and Drug Administration-Approval Study With a Continuous Flow Left Ventricular Assist Device as a Bridge to Heart Transplantation: A Prospective Study Using the INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support)

OBJECTIVES The aim of this study was to determine whether results with the HeartMate (HM) II left ventricular assist device (LVAD) (Thoratec Corporation, Pleasanton, California) in a commercial setting are comparable to other available devices for the same indication. BACKGROUND After a multicenter pivotal clinical trial conducted from 2005 to 2008, the U.S. Food and Drug Administration approved the HM II LVAD for bridge to transplantation (BTT). A post-approval study was required by the U.S. Food and Drug Administration to determine whether results with the device in a commercial setting are comparable to other available devices for the same indication. METHODS The study was a prospective evaluation of the first 169 consecutive HM II patients enrolled in the national INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) who were listed for transplant or likely to be listed. Patients were enrolled from April through August 2008 at 77 U.S. centers and followed for at least 1 year after implant. A comparison group (COMP) included all patients (n = 169 at 27 centers) enrolled in the INTERMACS registry with other types of LVADs (79% HeartMate XVE, 21% Implantable Ventricular Assist Device [Thoratec Corporation]) for the same BTT indication in the same time period. Survival rates, adverse events, and quality of life with the EuroQol EQ-5D visual analog scale were obtained in the INTERMACS registry. RESULTS Baseline characteristics were similar, but creatinine and blood urea nitrogen were lower in the HM II versus COMP groups, and there were fewer patients in the highest-risk INTERMACS patient profile Number 1 (24% for HM II vs. 39% for COMP). Adverse event rates were similar or lower for HM II versus COMP for all events. Bleeding was the most frequent adverse event for both groups (1.44 vs. 1.79 events/patient-year). Operative 30-day mortality for HM II was 4% versus 11% for COMP. The percentage of patients reaching transplant, cardiac recovery, or ongoing LVAD support by 6 months was 91% for HM II and 80% for COMP, and the Kaplan-Meier survival for patients remaining on support at 1 year was 85% for HM II versus 70% for COMP. Quality of life was significantly improved at 3 months of support and sustained through 12 months in both groups compared with baseline. CONCLUSIONS The results in a post-market approval, actual patient care setting BTT population support the original findings from the pivotal clinical trial regarding the efficacy and risk profile of the HM II LVAD. These data suggest that dissemination of this technology after approval has been associated with continued excellent results.

Acquired von Willebrand Syndrome After Continuous-Flow Mechanical Device Support Contributes to a High Prevalence of Bleeding During Long-Term Support and at the Time of Transplantation

OBJECTIVES The objective of the study was to determine the prevalence of bleeding during continuous-flow left ventricular assist device support and to identify potential mechanisms for those bleeding events. BACKGROUND Bleeding is frequently reported with continuous-flow left ventricular assist devices and may result from anticoagulation coupled with bleeding diathesis such as acquired von Willebrand syndrome. Accordingly, the prevalence of coagulation abnormalities including laboratory assessment for von Willebrand syndrome, bleeding events during device support, and at heart transplantation were evaluated. METHODS A retrospective study in all HeartMate II (HM II) (Thoratec Corp., Pleasanton, California) patients who underwent implantation between April 1, 2004, and August 1, 2009, was performed. Bleeding was defined as the need for transfusion >7 days after device insertion of 1 U of packed red blood cells. Transfusion at heart transplantation was compared with that in HeartMate XVE patients. RESULTS Seventy-nine HM II devices were implanted. Anticoagulation included warfarin in 68.3%, aspirin in 55.7%, and dipyridamole in 58.2% of the patients. Of the patients, 44.3% had bleeding episodes at 112 ± 183 days after left ventricular assist device implantation, with 50% experiencing an event within 2 months. Gastrointestinal bleeding was the most frequent event. At the index event, the international normalized ratio averaged 1.67 ± 0.53, and the platelet count was 237 ± 119 × 10(9)/l. Comparison of the transfusion requirements at heart transplantation of 35 HM II patients with 62 HeartMate XVE patients demonstrated twice the transfusion requirements in HM II patients (packed red blood cells, 6.3 ± 0.8 U vs. 3.8 ± 0.5 U; platelets, 12.5 ± 5.4 U vs. 8.6 ± 6.4 U; fresh frozen plasma, 9.6 ± 4.9 U vs. 4.9 ± 3.6 U; and cryoprecipitate, 4.3 ± 3.6 U vs. 2.2 ± 3.5 U; p < 0.05 for all). High molecular weight von Willebrand factor multimers were measured in 31 HM II patients and were reduced in all patients; 18 of these 31 (58%) patients had bleeding. CONCLUSIONS Patients with the HM II had a high incidence of bleeding events during device support and at heart transplantation. All HM II patients had reduced high molecular weight von Willebrand factor multimers. The role of these abnormalities in the high incidence of bleeding deserves further investigation. Furthermore, alterations in anticoagulation should be considered during device support and before surgery in patients supported with the HM II.

Development of a Novel Echocardiography Ramp Test for Speed Optimization and Diagnosis of Device Thrombosis in Continuous-Flow Left Ventricular Assist Devices: The Columbia Ramp Study

OBJECTIVES This study sought to develop a novel approach to optimizing continuous-flow left ventricular assist device (CF-LVAD) function and diagnosing device malfunctions. BACKGROUND In CF-LVAD patients, the dynamic interaction of device speed, left and right ventricular decompression, and valve function can be assessed during an echocardiography-monitored speed ramp test. METHODS We devised a unique ramp test protocol to be routinely used at the time of discharge for speed optimization and/or if device malfunction was suspected. The patients left ventricular end-diastolic dimension, frequency of aortic valve opening, valvular insufficiency, blood pressure, and CF-LVAD parameters were recorded in increments of 400 rpm from 8,000 rpm to 12,000 rpm. The results of the speed designations were plotted, and linear function slopes for left ventricular end-diastolic dimension, pulsatility index, and power were calculated. RESULTS Fifty-two ramp tests for 39 patients were prospectively collected and analyzed. Twenty-eight ramp tests were performed for speed optimization, and speed was changed in 17 (61%) with a mean absolute value adjustment of 424 ± 211 rpm. Seventeen patients had ramp tests performed for suspected device thrombosis, and 10 tests were suspicious for device thrombosis; these patients were then treated with intensified anticoagulation and/or device exchange/emergent transplantation. Device thrombosis was confirmed in 8 of 10 cases at the time of emergent device exchange or transplantation. All patients with device thrombosis, but none of the remaining patients had a left ventricular end-diastolic dimension slope >-0.16. CONCLUSIONS Ramp tests facilitate optimal speed changes and device malfunction detection and may be used to monitor the effects of therapeutic interventions and need for surgical intervention in CF-LVAD patients.

Maximally Recommended Doses of Angiotensin-Converting Enzyme (ACE) Inhibitors Do Not Completely Prevent ACE-Mediated Formation of Angiotensin II in Chronic Heart Failure

BACKGROUND The added benefits of angiotensin II type I receptor (AT(1)) blockers (ARBs) to ACE inhibition suggests that recommended doses of ACE inhibitors provide only partial inhibition of ACE in chronic heart failure (CHF). Accordingly, the level of ACE inhibition was assessed by the pressor response to angiotensin (Ang) I in patients who had been treated with recommended doses of ACE inhibitors. METHODS AND RESULTS Forty-two patients with CHF receiving 40 mg/d of a long-acting ACE inhibitor or 150 mg of captopril were studied. Radial artery systolic pressure (RASP, mm Hg) was monitored noninvasively. The pressor response to ascending doses of Ang I was evaluated in all patients before and after administration of the ARB valsartan. The pressor response to Ang I before and after valsartan was also reevaluated in 11 patients after the dose of ACE inhibitor was doubled for 1 week. RASP increased linearly with significantly ascending doses of Ang I despite treatment with ACE inhibitors. The pressor response to Ang I was blunted significantly by valsartan. Ang I-induced increase in RASP did not correlate with duration of ACE inhibitor therapy. After the dose of ACE inhibitors was doubled, the pressor response to Ang I was no longer different from that noted after valsartan. CONCLUSIONS Recommended doses of ACE inhibitors do not fully inhibit ACE in CHF. The level of ACE inhibition achieved is not related to duration of ACE inhibitor therapy. Greater ACE inhibition is also achieved at twice the recommended doses of ACE inhibitors.

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.)

Prevalence of de novo aortic insufficiency during long-term support with left ventricular assist devices

BACKGROUND Left ventricular assist devices (LVADs) are increasingly used as long-term therapy for end-stage heart failure patients. We compared the prevalence of aortic insufficiency (AI) after HeartMate II (HMII) vs HeartMate XVE (HMI) support and assessed the role of aortic root diameter and aortic valve opening in the development of AI. METHOD Pre-operative and post-operative echocardiograms of 93 HMI and 73 HMII patients who received implants at our center between January 2004 and September 2009 were retrospectively reviewed. After excluding patients with prior or concurrent surgical manipulation of the aortic valve, with baseline AI, or without baseline echoes, 67 HMI and 63 HMII patients were studied. AI was deemed significant if mild to moderate or greater. Pathology reports were reviewed for 77 patients who underwent heart transplant. RESULTS AI developed in 4 of 67 HMI (6.0%) and in 9 of 63 HMII patients (14.3%). The median times to AI development were 48 days for HMI patients and 90 days for HMII patients. For patients who remained on device support at 6 and 12 months, freedom from AI was 94.5% and 88.9% in HMI patients and 83.6% and 75.2% in HMII patients (log rank p = 0.194). Aortic root diameters, as determined by echocardiography for the patients with AI, trended to be larger at baseline (3.43 ± 0.43 vs 3.15 ± 0.40; p = 0.067) and follow-up (3.58 ± 0.54 vs 3.29 ± 0.50; p = 0.130) compared with those who did not have AI. Aortic root circumferences were assessed directly by a pathologist in those patients who underwent transplant and were significantly larger in HMII patients who had developed AI compared with those patients who did not (8.44 ± 0.89 vs 7.36 ± 1.02 cm; p = 0.034). Lastly, AI was more common in patients whose aortic valve did not open (11 of 26 vs 1 of 14; p = 0.03). CONCLUSION Aortic insufficiency occurs frequently in patients who receive continuous-flow support with a HMII LVAD, and may be associated with aortic root diameter enlargement and aortic valve opening. These findings warrant a more thorough preoperative patient evaluation and additional studies to investigate the factors, that may be associated with AI development.

Ventricular Assist Device Implantation Corrects Myocardial Lipotoxicity, Reverses Insulin Resistance, and Normalizes Cardiac Metabolism in Patients With Advanced Heart Failure

Background— Heart failure is associated with impaired myocardial metabolism with a shift from fatty acids to glucose use for ATP generation. We hypothesized that cardiac accumulation of toxic lipid intermediates inhibits insulin signaling in advanced heart failure and that mechanical unloading of the failing myocardium corrects impaired cardiac metabolism. Methods and Results— We analyzed the myocardium and serum of 61 patients with heart failure (body mass index, 26.5±5.1 kg/m2; age, 51±12 years) obtained during left ventricular assist device implantation and at explantation (mean duration, 185±156 days) and from 9 control subjects. Systemic insulin resistance in heart failure was accompanied by decreased myocardial triglyceride and overall fatty acid content but increased toxic lipid intermediates, diacylglycerol, and ceramide. Increased membrane localization of protein kinase C isoforms, inhibitors of insulin signaling, and decreased activity of insulin signaling molecules Akt and Foxo were detectable in heart failure compared with control subjects. Left ventricular assist device implantation improved whole-body insulin resistance (homeostatic model of analysis–insulin resistance, 4.5±0.6–3.2±0.5; P<0.05) and decreased myocardial levels of diacylglycerol and ceramide, whereas triglyceride and fatty acid content remained unchanged. Improved activation of the insulin/phosphatidylinositol-3 kinase/Akt signaling cascade after left ventricular assist device implantation was confirmed by increased phosphorylation of Akt and Foxo, which was accompanied by decreased membrane localization of protein kinase C isoforms after left ventricular assist device implantation. Conclusions— Mechanical unloading after left ventricular assist device implantation corrects systemic and local metabolic derangements in advanced heart failure, leading to reduced myocardial levels of toxic lipid intermediates and improved cardiac insulin signaling.

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.

Endothelial Cell Activation in Patients With Decompensated Heart Failure

Background—Vascular endothelial functions, other than nitric oxide (NO)–mediated control of vasomotor tone, are poorly characterized in patients with chronic heart failure (CHF). Veins and arteries are exposed to the same circulating proinflammatory mediators in patients with CHF. The present study tested whether endothelial cell activation occurs in veins of patients with decompensated CHF and whether activation, if present, subsides with return to a clinically compensated state. Methods and Results—Fifteen patients with decompensated CHF requiring transient inotropic support and 6 age-matched, healthy controls were studied. Endothelial cells and blood were collected from a forearm vein, and brachial artery flow–mediated dilation (FMD) was measured before and 24 hours after discontinuation of short-term inotropic therapy, when patients had returned to a steady compensated state. Nitrotyrosine immunoreactivity (an intracellular marker of oxidative stress), cyclooxygenase-2 (COX-2), and inducible NO synthase (iNOS) expression were significantly higher in venous endothelial cells of patients in clinical decompensation when compared with healthy subjects. Return to a compensated state resulted in a significant reduction in nitrotyrosine immunoreactivity, COX-2, and iNOS expression. Concomitantly, a significant increase in FMD and a decline in plasma total 8-isoprostane and bicycloprostaglandin E2 levels were observed. Venous endothelial NOS expression was unaffected by clinical decompensation. Conclusions—Clinical decompensation in CHF is associated with activation of the venous endothelium. Return to a compensated state after short-term inotropic therapy results in a significant reduction in endothelial nitrotyrosine formation, COX-2, and iNOS expression.