Reverse Remodeling With Left Ventricular Assist Devices.

This review provides a comprehensive overview of the past 25+ years of research into the development of left ventricular assist device (LVAD) to improve clinical outcomes in patients with severe end-stage heart failure and basic insights gained into the biology of heart failure gleaned from studies of hearts and myocardium of patients undergoing LVAD support. Clinical aspects of contemporary LVAD therapy, including evolving device technology, overall mortality, and complications, are reviewed. We explain the hemodynamic effects of LVAD support and how these lead to ventricular unloading. This includes a detailed review of the structural, cellular, and molecular aspects of LVAD-associated reverse remodeling. Synergisms between LVAD support and medical therapies for heart failure related to reverse remodeling, remission, and recovery are discussed within the context of both clinical outcomes and fundamental effects on myocardial biology. The incidence, clinical implications and factors most likely to be associated with improved ventricular function and remission of the heart failure are reviewed. Finally, we discuss recognized impediments to achieving myocardial recovery in the vast majority of LVAD-supported hearts and their implications for future research aimed at improving the overall rates of recovery.

First in man evaluation of a novel circulatory support device: Early experience with the Impella 5.5 after CE mark approval in Germany.

BACKGROUND: The Abiomed Impella 5.5 (Danvers, MA) is a newly developed axial flow transaortic cardiac support device mounted on a 9 Fr steering catheter with a 21 Fr pump cannula. Impella 5.5 is intended for longer use and was approved for 30 days in 2018. This study evaluated the first-in-man series at six high-volume mechanical circulatory support centers in Germany after CE approval. METHODS: The first 46 consecutive patients worldwide underwent implantation in six German centers between March 2018 and September 2019 for post-CE approval evaluation. The primary end-point was 30 days and 90 days all-cause mortality. RESULTS: The mean age of patients was 59.0 ± 11.5 years, and 43 (93.4%) were men. Half of the patients had acute on chronic heart failure. The main indication for Impella 5.5 implantation was ischemic cardiomyopathy and acute myocardial infarction (47.8%). The mean support time was 15.5 ± 24.2 days (range 0-164, median 10 days (IQR = 7-19)) with a total of 712 patient-days on support. The 30 days and 90 days survival rates were 73.9% (95% CI: 63.3-88.9%) and 71.7% (95% CI: 60.7-87.1%), respectively. Additionally, 16 patients (34.8%) were weaned from the device for native heart recovery, and 19 (41.3%) were bridged to a durable device. Fifteen patients (32.6%) were mobilized to a chair, and 15 (32.6%) were ambulatory. We only noted one stroke and found no other thromboembolic complications. No aortic valve damage was observed in the study cohort. Finally, seven patients (15.2 %) had pump thrombosis, and nine (19.6 %) underwent device exchange. Sixteen patients (34.8 %) suffered from bleeding requiring transfusions during the whole treatment course. In ten patients (21.7%), the inflow cannula dislocated into the aortic root. CONCLUSIONS: The first version of the Impella 5.5 presents promising early outcomes for patients with acute heart failure and expands the spectrum of available devices. The adverse event profile is favorable for short-term devices. Dislocations have been addressed by design changes. With increasing experience with this device, our study suggests that the indications for use will expand to other cardiac shock etiologies and may improve myocardial recovery and survival in patients with cardiogenic shock.

Using machine learning to improve risk prediction in durable left ventricular assist devices.

Risk models have historically displayed only moderate predictive performance in estimating mortality risk in left ventricular assist device therapy. This study evaluated whether machine learning can improve risk prediction for left ventricular assist devices. Primary durable left ventricular assist devices reported in the Interagency Registry for Mechanically Assisted Circulatory Support between March 1, 2006 and December 31, 2016 were included. The study cohort was randomly divided 3:1 into training and testing sets. Logistic regression and machine learning models (extreme gradient boosting) were created in the training set for 90-day and 1-year mortality and their performance was evaluated after bootstrapping with 1000 replications in the testing set. Differences in model performance were also evaluated in cases of concordance versus discordance in predicted risk between logistic regression and extreme gradient boosting as defined by equal size patient tertiles. A total of 16,120 patients were included. Calibration metrics were comparable between logistic regression and extreme gradient boosting. C-index was improved with extreme gradient boosting (90-day: 0.707 [0.683-0.730] versus 0.740 [0.717-0.762] and 1-year: 0.691 [0.673-0.710] versus 0.714 [0.695-0.734]; each p<0.001). Net reclassification index analysis similarly demonstrated an improvement of 48.8% and 36.9% for 90-day and 1-year mortality, respectively, with extreme gradient boosting (each p<0.001). Concordance in predicted risk between logistic regression and extreme gradient boosting resulted in substantially improved c-index for both logistic regression and extreme gradient boosting (90-day logistic regression 0.536 versus 0.752, 1-year logistic regression 0.555 versus 0.726, 90-day extreme gradient boosting 0.623 versus 0.772, 1-year extreme gradient boosting 0.613 versus 0.742, each p<0.001). These results demonstrate that machine learning can improve risk model performance for durable left ventricular assist devices, both independently and as an adjunct to logistic regression.

Managing Patients With Short-Term Mechanical Circulatory Support: JACC Review Topic of the Week.

The use of mechanical circulatory support for patients presenting with cardiogenic shock is rapidly increasing. Currently, there is only limited and conflicting evidence available regarding the role of the Impella (a microaxial, continuous-flow, short-term, left or right ventricular assist device) in cardiogenic shock; further randomized trials are needed. Patient selection, timing of implantation, and post-implantation management in the cardiac intensive care unit are crucial elements for success. Particular challenges at the bedside include the practical management of anticoagulation, evaluation of correct device position, and the approach to use in a patient with signs of insufficient hemodynamic support. Profound knowledge of these issues is required to enable the maximal potential of the device. This review provides a comprehensive overview of the short-term assist device and describes a practical approach to optimize care for patients supported with the device.

Use of Mechanical Circulatory Support Devices Among Patients With Acute Myocardial Infarction Complicated by Cardiogenic Shock.

Importance: Mechanical circulatory support (MCS) devices, including intravascular microaxial left ventricular assist devices (LVADs) and intra-aortic balloon pumps (IABPs), are used in patients who undergo percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) complicated by cardiogenic shock despite limited evidence of their clinical benefit. Objective: To examine trends in the use of MCS devices among patients who underwent PCI for AMI with cardiogenic shock, hospital-level use variation, and factors associated with use. Design, Setting, and Participants: This cross-sectional study used the CathPCI and Chest Pain-MI Registries of the American College of Cardiology National Cardiovascular Data Registry. Patients who underwent PCI for AMI complicated by cardiogenic shock between October 1, 2015, and December 31, 2017, were identified from both registries. Data were analyzed from October 2018 to August 2020. Exposures: Therapies to provide hemodynamic support were categorized as intravascular microaxial LVAD, IABP, TandemHeart, extracorporeal membrane oxygenation, LVAD, other devices, combined IABP and intravascular microaxial LVAD, combined IABP and other device (defined as TandemHeart, extracorporeal membrane oxygenation, LVAD, or another MCS device), or medical therapy only. Main Outcomes and Measures: Use of MCS devices overall and specific MCS devices, including intravascular microaxial LVAD, at both patient and hospital levels and variables associated with use. Results: Among the 28 304 patients included in the study, the mean (SD) age was 65.4 (12.6) years and 18 968 were men (67.0%). The overall MCS device use was constant from the fourth quarter of 2015 to the fourth quarter of 2017, although use of intravascular microaxial LVADs significantly increased (from 4.1% to 9.8%; P < .001), whereas use of IABPs significantly decreased (from 34.8% to 30.0%; P < .001). A significant hospital-level variation in MCS device use was found. The median (interquartile range [IQR]) proportion of patients who received MCS devices was 42% (30%-54%), and the median proportion of patients who received intravascular microaxial LVADs was 1% (0%-10%). In multivariable analyses, cardiac arrest at first medical contact or during hospitalization (odds ratio [OR], 1.82; 95% CI, 1.58-2.09) and severe left main and/or proximal left anterior descending coronary artery stenosis (OR, 1.36; 95% CI, 1.20-1.54) were patient characteristics that were associated with higher odds of receiving intravascular microaxial LVADs only compared with IABPs only. Conclusions and Relevance: This study found that, among patients who underwent PCI for AMI complicated by cardiogenic shock, overall use of MCS devices was constant, and a 2.5-fold increase in intravascular microaxial LVAD use was found along with a corresponding decrease in IABP use and a significant hospital-level variation in MCS device use. These trends were observed despite limited clinical trial evidence of improved outcomes associated with device use.

Waitlist and Post-Heart Transplant Outcomes for Children With Nondilated Cardiomyopathy.

BACKGROUND: Although outcomes for pediatric cardiomyopathy (CMP) patients have improved, an understanding of outcomes by CMP phenotype is essential. This study assessed changes in waitlist and post-transplant survival in nondilated cardiomyopathy (DCM) patients over 2 decades, explored ventricular assist device (VAD) utilization in this cohort, and identified risk factors for waitlist and posttransplant mortality in the current era. METHODS: Pediatric patients with a diagnosis of CMP listed for heart transplantation during three eras: Era 1: March 5, 1999 to December 31, 2004; Era 2: January 1, 2005 to December 15, 2011; and Era 3 (current era): December 16, 2011 to February 28, 2018 were included. Multivariable Cox proportional hazards regression was performed to assess waitlist and posttransplant survival. RESULTS: Compared with patients with DCM, those with hypertrophic and restrictive cardiomyopathy in the current era are less likely to be on VAD (23.4% vs 2.7% vs 4.5%); listed United Network for Organ Sharing Status 1A (75.6% vs 39.8% vs 34.8%), and more likely to have longer waitlist times (P < .01 for all). Only 3.3% hypertrophic and 2.4% restrictive cardiomyopathy patients had VAD implantation, although VAD use did not adversely impact waitlist survival in weighted non-DCM patients. Significant improvements have occurred in waitlist survival of hypertrophic and posttransplant survival of both types of non-DCM patients. CONCLUSIONS: Currently, waitlist and posttransplant survival is similar for all CMP phenotypes. VAD use is low in patients with non-DCM, although this did not increase waitlist mortality in adjusted analysis. Further studies in patients with non-DCM are needed to determine optimal timing and anatomic characteristics most likely to benefit from VAD implantation during the waitlist period.

Cardiogenic shock: incidence, survival and mechanical circulatory support usage 2007-2017-insights from a national registry.

BACKGROUND: A central element in the management of cardiogenic shock (CS) comprises mechanical circulatory support (MCS) systems to maintain cardiac output (CO). This study aims to quantify incidence, outcome and influence of MCS in CS over the last decade. METHODS: All patients hospitalized with CS in a tertiary university hospital in Germany between 2007 and 2017 were identified utilizing the international coding system ICD-10 with code R57.0. Application of MCS was identified via German procedure classification codes (OPS). RESULTS: 383,983 cases of cardiogenic shock were reported from 2007 to 2017. Patients had a mean age of 71 years and 38.5% were female. The incidence of CS rose by 65.6% from 26,828 cases in 2007 (33.1 per 100,000 person-years, hospital survival 39.2%) to 44,425 cases in 2017 (53.7 per 100,000 person-years, survival 41.2%). In 2007, 16.0% of patients with CS received MCS (4.6 per 100,000 person-years, survival 46.6%), dropping to 13.9% in 2017 (6.6 per 100,000 person-years, survival 38.6%). Type of MCS changed over the years, with decreasing use of the intra-aortic balloon pump (IABP), an increase in extracorporeal membrane oxygenation (VA-ECMO) and percutaneous ventricular assist device (pVAD) usage. Significant differences regarding in-hospital survival were observed between the devices (survival: overall: 40.2%; medical treatment = 39.5%; IABP = 49.5%; pVAD = 36.2%; VA-ECMO = 30.5%; p < 0.001). CONCLUSIONS: The incidence of CS is increasing, but hospital survival remains low. MCS was used in a minority of patients, and the percentage of MCS usage in CS has decreased. The use rates of the competing devices change over time.

Heart transplant outcomes in patients with mechanical circulatory support: cold storage versus normothermic perfusion organ preservation.

OBJECTIVES: Patients with mechanical circulatory support bridged to a heart transplant (HTx) are at higher risk of postoperative graft dysfunction. In this subset, a mode of graft preservation that shortens graft ischaemia should be beneficial. METHODS: The outcomes of 38 patients on mechanical circulatory support (extracorporeal life support, left ventricular assist device and biventricular assist device) who received a HTx between 2015 and 2020 were analysed according to the method of graft preservation: cold storage (CS) group, 24 (63%) or ex vivo perfusion (EVP) group, 14 (37%). RESULTS: The median age was 57 (range 30-73) vs 64 (35-75) years (P = 0.10); 88% were men (P = 0.28); extracorporeal life support was more frequent in the CS group (54% vs 36%; P = 0.27) versus left ventricular and biventricular assist devices in the EVP group (46% vs 64%; P = 0.27). Clamping time was shorter in the EVP group (P < 0.001) and ischaemic time >4 h was higher in the CS group (P = 0.01). Thirty-day mortality was 13% (0-27%) in the CS group and 0% (P = 0.28) in the EVP group. A significantly lower primary graft failure [7% (0-23%) vs 42% (20-63%); P = 0.03] was observed in the EVP group. Survival at 1 year was 79 ± 8% (63-95%) in the CS group and 84 ± 10% (64-104%) in the EVP group (P = 0.95). CONCLUSIONS: Our results support the use of ex vivo graft perfusion in patients on mechanical circulatory support as a bridge to a HTx. This technique, by shortening graft ischaemic time, seems to improve post-HTx outcomes.

Trends, Perioperative Adverse Events, and Survival of Patients With Left Ventricular Assist Devices Undergoing Noncardiac Surgery.

Importance: Information regarding the performance and outcomes of noncardiac surgery (NCS) in patients with left ventricular assist devices (LVADs) is scarce, with limited longitudinal follow-up data that are mostly limited to single-center reports. Objective: To examine the trends, patient characteristics, and outcomes associated with NCS among patients with LVAD. Design, Setting, and Participants: This cohort study examined patients enrolled in Medicare undergoing durable LVAD implantation from January 2012 to November 2017 with follow-up through December 2017. The study included all Medicare Provider and Analysis Review Part A files for the years 2012 to 2017. Patients identified by International Classification of Diseases, Ninth Revision Clinical Modification (ICD-9-CM) and International Classification of Diseases, Tenth Revision (ICD-10) procedure codes for new LVAD implantation were included. Data analysis was performed from November 2019 to February 2020. Exposures: NCS procedures were identified using the ICD-9-CM and ICD-10 procedural codes and divided into elective and urgent or emergent. Main Outcomes and Measures: The primary outcome was major adverse cardiovascular events (MACEs), defined as in-hospital or 30-day all-cause mortality, ischemic stroke, or intracerebral hemorrhage after NCS. Early (<60 days after NCS) and late (≥60 days after NCS) mortality after NCS were analyzed in both subgroups using time-varying covariate and landmark analysis using patients who did not undergo NCS as reference. Results: Of the 8118 patients with LVAD (mean [SD] age, 63.4 [10.8] years; 6484 men [79.9%]), 1326 (16.3%, or approximately 1 in 6) underwent NCS, of which 1000 procedures (75.4%) were emergent or urgent and 326 (24.6%) were elective. There was no difference in age between patients who underwent NCS and patients who did not (mean [SD] age, 63.6 [10.6] vs 63.4 [10.9] years). The number of NCS procedures among patients with LVAD increased from 64 in 2012 to 304 in 2017. The median (interquartile range) time from LVAD implantation to NCS was 309 (133-606) days. The most frequent type of NCS was general (613 abdominal, pelvic, and gastrointestinal procedures [46.2%]). Perioperative MACEs occurred in 169 patients (16.9%) undergoing emergent or urgent NCS and 23 patients (7.1%) undergoing elective NCS. Urgent or emergent NCS was associated with higher mortality early (adjusted hazard ratio [aHR], 8.78; 95% CI, 7.20-10.72; P < .001) and late (aHR, 1.71; 95% CI, 1.53-1.90; P < .001) after NCS compared with patients with LVAD who did not undergo NCS. Elective NCS was also associated with higher mortality early (aHR, 2.65; 95% CI, 1.74-4.03; P < .001) and late (aHR, 1.29; 95% CI, 1.07-1.56; P = .008) after NCS. Conclusions and Relevance: One of 6 patients with LVAD underwent NCS. Perioperative MACEs were frequent. Higher mortality risk transcended the early postoperative period in urgent or emergent and elective surgical procedures.

Prospective Multicenter Study of Myocardial Recovery Using Left Ventricular Assist Devices (RESTAGE-HF [Remission from Stage D Heart Failure]): Medium-Term and Primary End Point Results.

BACKGROUND: Left ventricular assist device (LVAD) unloading and hemodynamic support in patients with advanced chronic heart failure can result in significant improvement in cardiac function allowing LVAD removal; however, the rate of this is generally considered to be low. This prospective multicenter nonrandomized study (RESTAGE-HF [Remission from Stage D Heart Failure]) investigated whether a protocol of optimized LVAD mechanical unloading, combined with standardized specific pharmacological therapy to induce reverse remodeling and regular testing of underlying myocardial function, could produce a higher incidence of LVAD explantation. METHODS: Forty patients with chronic advanced heart failure from nonischemic cardiomyopathy receiving the Heartmate II LVAD were enrolled from 6 centers. LVAD speed was optimized with an aggressive pharmacological regimen, and regular echocardiograms were performed at reduced LVAD speed (6000 rpm, no net flow) to test underlying myocardial function. The primary end point was the proportion of patients with sufficient improvement of myocardial function to reach criteria for explantation within 18 months with sustained remission from heart failure (freedom from transplant/ventricular assist device/death) at 12 months. RESULTS: Before LVAD, age was 35.1±10.8 years, 67.5% were men, heart failure mean duration was 20.8±20.6 months, 95% required inotropic and 20% temporary mechanical support, left ventricular ejection fraction was 14.5±5.3%, end-diastolic diameter was 7.33±0.89 cm, end-systolic diameter was 6.74±0.88 cm, pulmonary artery saturations were 46.7±9.2%, and pulmonary capillary wedge pressure was 26.2±7.6 mm Hg. Four enrolled patients did not undergo the protocol because of medical complications unrelated to the study procedures. Overall, 40% of all enrolled (16/40) patients achieved the primary end point, P<0.0001, with 50% (18/36) of patients receiving the protocol being explanted within 18 months (pre-explant left ventricular ejection fraction, 57±8%; end-diastolic diameter, 4.81±0.58 cm; end-systolic diameter, 3.53±0.51 cm; pulmonary capillary wedge pressure, 8.1±3.1 mm Hg; pulmonary artery saturations 63.6±6.8% at 6000 rpm). Overall, 19 patients were explanted (19/36, 52.3% of those receiving the protocol). The 15 ongoing explanted patients are now 2.26±0.97 years after explant. After explantation survival free from LVAD or transplantation was 90% at 1-year and 77% at 2 and 3 years. CONCLUSIONS: In this multicenter prospective study, this strategy of LVAD support combined with a standardized pharmacological and cardiac function monitoring protocol resulted in a high rate of LVAD explantation and was feasible and reproducible with explants occurring in all 6 participating sites. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01774656.

Clinical Impact of Hematoma Expansion in Left Ventricular Assist Device Patients.

BACKGROUND: Hematoma expansion (HE) is associated with poor outcome in patients with intracerebral hemorrhage (ICH), but the impact on patients with an left ventricular assist device (LVAD) is unknown. We aimed to define the occurrence of HE in the LVAD population and to determine the association between HE and mortality. METHODS: We performed a retrospective cohort study of LVAD patients and intentionally matched anticoagulated controls without LVAD admitted to Columbia University Irving Medical Center with ICH between 2008 and 2019. We compared HE occurrence between patients with an LVAD and those without an LVAD using regression modeling, adjusting for factors known to influence HE. We evaluated pump thrombosis following anticoagulation reversal. We examined the association between HE and hospital mortality using Poisson regression modeling adjusting for factors associated with poor outcome. RESULTS: Among 605 patients with an LVAD, we identified 28 patients with ICH meeting the study's inclusion criteria. Our LVAD ICH cohort was predominantly male (71%), with a mean age of 56 ± 10 years. The median baseline hematoma size was 20.1 mL3 (interquartile range [IQR], 8.6-46.9 mL3), and the median ICH score was 1 (IQR, 1-2). There was no significant difference in occurrence of HE in LVAD patients and matched non-LVAD patients (adjusted odds ratio [OR], 1.3; 95% confidence interval [CI], 0.4-4.2). There was an association between HE and in-hospital mortality in LVAD patients (adjusted OR, 4.8; 95% CI, 1.4-6.2). CONCLUSIONS: HE occurrence appears to be similar in LVAD and non-LVAD patients. HE has a significant impact on LVAD ICH mortality, underscoring the importance of adequate coagulopathy reversal and blood pressure management in these patients.

Balloon Pump Counterpulsation Part II: Perioperative Hemodynamic Support and New Directions.

Intraaortic balloon pump (IABP) counterpulsation, introduced more than 50 years ago, remains the most commonly utilized mechanical circulatory support device for patients with cardiogenic shock and myocardial ischemia, despite lack of definitive proof regarding its outcome in these patients. Part I of this review focused on the history of counterpulsation, physiologic principles, technical considerations, and evidence for its use in cardiogenic shock; Part II will discuss periprocedural uses for IABP counterpulsation and review advances in technology, including the emergence of alternative mechanical circulatory support devices that have influenced IABP utilization.

Clinical presentation and outcomes in women and men with advanced heart failure.

OBJECTIVE: To examine clinical characteristics and outcomes in women and men referred for advanced heart failure (HF) therapies such as left ventricular assist device (LVAD) or heart transplantation (HTx). Design: A retrospective study of 429 (23% women) consecutive adult HF patients not on inotropic or mechanical circulatory support with left ventricular ejection fraction ≤45% referred for assessment of advanced HF therapies at a single tertiary institution between 2002 and 2016. Clinical characteristics and outcomes were compared in women and men, and all patients underwent right heart catheterization (RHC). Results: At evaluation, women were younger than men (48 ± 13 vs. 51 ± 12 years, p = .02), and less likely to have ischemic cardiomyopathy. There were no significant differences in NYHA class, contemporary HF therapy use, or physical examination findings, except for lower jugular vein distension and body surface area in women. On RHC, women had lower cardiac filling pressures, but similar pulmonary vascular resistance and cardiac index. Peak oxygen uptake from cardiopulmonary exercise testing was similar in both sexes. At total follow-up time, there were 164 deaths (21% vs. 44%, p < .0001), 46 LVADs (3% vs. 13%, p = .005), 110 HTxs (32% vs. 25%, p = .15), and 82 HTxs without requiring LVAD (29% vs. 16%, p = .03) in women and men. The time from RHC to HTx (±LVAD) was significantly shorter in women compared to men. Female sex was significantly associated with higher survival independent of time-trend, age, and comorbidities. Conclusion: At evaluation, hemodynamics were less deranged in women. A higher proportion of women received HTx, their waitlist time was shorter, and survival greater.