Rejection Surveillance After Heart Transplantation: Is Paired Noninvasive Testing the New Gold Standard?

Rejection surveillance after heart transplantation has traditionally relied on numerous endomyocardial biopsies, most of which occur during the first posttransplant year. With the introduction of gene expression profiling and, more recently, donor-derived cell-free DNA, a great proportion of surveillance is being performed noninvasively with both tests. Although patients have welcomed the use of paired testing because of the decreased risk and inconvenience, interpretation of both tests can sometimes be challenging, particularly when the test results are discordant. Growing evidence from both single-center experiences and large national databases has given insights that have allowed the field to operationalize dual testing and provide physicians with algorithms to approach paired testing. The increased use of noninvasive testing has also begun to challenge the role of biopsy as the gold standard for graft monitoring, not only for rejection but over the life of the heart transplant. In a growing number of circumstances, cell-free DNA not only may be a better means of assessing rejection but could also redefine how clinicians approach the diagnosis and even treatment of graft injury. As the heart transplant community garners more experience and generates more data, the current paradigms of heart transplant surveillance will continue to be challenged.

Cloud-Based Machine Learning Platform to Predict Clinical Outcomes at Home for Patients With Cardiovascular Conditions Discharged From Hospital: Clinical Trial.

BACKGROUND: Hospitalizations account for almost one-third of the US $4.1 trillion health care cost in the United States. A substantial portion of these hospitalizations are attributed to readmissions, which led to the establishment of the Hospital Readmissions Reduction Program (HRRP) in 2012. The HRRP reduces payments to hospitals with excess readmissions. In 2018, >US $700 million was withheld; this is expected to exceed US $1 billion by 2022. More importantly, there is nothing more physically and emotionally taxing for readmitted patients and demoralizing for hospital physicians, nurses, and administrators. Given this high uncertainty of proper home recovery, intelligent monitoring is needed to predict the outcome of discharged patients to reduce readmissions. Physical activity (PA) is one of the major determinants for overall clinical outcomes in diabetes, hypertension, hyperlipidemia, heart failure, cancer, and mental health issues. These are the exact comorbidities that increase readmission rates, underlining the importance of PA in assessing the recovery of patients by quantitative measurement beyond the questionnaire and survey methods. OBJECTIVE: This study aims to develop a remote, low-cost, and cloud-based machine learning (ML) platform to enable the precision health monitoring of PA, which may fundamentally alter the delivery of home health care. To validate this technology, we conducted a clinical trial to test the ability of our platform to predict clinical outcomes in discharged patients. METHODS: Our platform consists of a wearable device, which includes an accelerometer and a Bluetooth sensor, and an iPhone connected to our cloud-based ML interface to analyze PA remotely and predict clinical outcomes. This system was deployed at a skilled nursing facility where we collected >17,000 person-day data points over 2 years, generating a solid training database. We used these data to train our extreme gradient boosting (XGBoost)-based ML environment to conduct a clinical trial, Activity Assessment of Patients Discharged from Hospital-I, to test the hypothesis that a comprehensive profile of PA would predict clinical outcome. We developed an advanced data-driven analytic platform that predicts the clinical outcome based on accurate measurements of PA. Artificial intelligence or an ML algorithm was used to analyze the data to predict short-term health outcome. RESULTS: We enrolled 52 patients discharged from Stanford Hospital. Our data demonstrated a robust predictive system to forecast health outcome in the enrolled patients based on their PA data. We achieved precise prediction of the patients' clinical outcomes with a sensitivity of 87%, a specificity of 79%, and an accuracy of 85%. CONCLUSIONS: To date, there are no reliable clinical data, using a wearable device, regarding monitoring discharged patients to predict their recovery. We conducted a clinical trial to assess outcome data rigorously to be used reliably for remote home care by patients, health care professionals, and caretakers.

Changing Strategy Between Bridge to Transplant and Destination LVAD Therapy After the First 3 Months: Analysis of the STS-INTERMACS Database.

BACKGROUND: Left ventricular assist devices (LVADs) have been implanted as bridge to transplantation (BTT), bridge to candidacy (BTC) or destination therapy (DT) on the basis of relative and absolute contraindications to transplantation. Multiple factors may lead to changes in the strategy of support after LVAD implantation. METHODS: Based on INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) 2012-2020 data, 11,262 patients survived to 3 months on continuous-flow LVADs with intent of BTT or DT. Preimplant characteristics and early events post-LVAD were analyzed in relation to changes in BTT or DT strategy during the next 12 months. RESULTS: Among 3216 BTT patients at 3 months, later transplant delisting or death without transplant occurred in 536 (16.7%) and was more common with age, profiles 1-2, renal dysfunction, and independently for prior cardiac surgery (HR 1.25, 95% CI 1.04-1.51; P = 0.02). Post-LVAD events of infections, gastrointestinal bleeding, stroke, and right heart failure as defined by inotropic therapy, predicted delisting and death, as did in-hospital location at 3 months (HR 1.67, 95% CI 1.20-2.33; P = 0.0024). Of 8046 patients surviving to 3 months with the intent of destination therapy, 750 (9.3%) subsequently underwent listing or transplantation, often with initial histories of acute HF (HR 1.70, 95% CI 1.27-2.27; P = 0.0012) or malnutrition-cachexia (1.73, 95% CI 1.14-2.63; P = 0.0099). Multiple gastrointestinal bleeding events (≥ 4) with LVAD increased transition from BTT to DT (HR 4.22, 95% CI 1.46-12.275; P = 0.0078) but also from DT to BTT (HR 5.17, 95% CI 1.92-13.9; P = 0.0011). CONCLUSIONS: Implant strategies change over time in relation to preimplant characteristics and adverse events post implant. Preimplant recognition of factors predicting later change in implant strategy will refine initial triage, whereas further reduction of post-LVAD complications will expand options, including eventual consideration of heart transplantation.

Concordance of Treatment Effect: An Analysis of The Society of Thoracic Surgeons Intermacs Database.

BACKGROUND: The Society of Thoracic Surgeons (STS) Intermacs Registry represents a real-world data source of durable, left ventricular assist devices that can address knowledge gaps not informed through randomized clinical trials. We sought to compare survival with contemporary left ventricular assist device technologies using multiple analytic approaches to assess concordance of treatment effects and to validate prior STS Intermacs observations. METHODS: Patients (≥19 years of age) enrolled into STS Intermacs between August 2017 and June 2019 were stratified by device type (continuous flow, centrifugal left ventricular assist device with hybrid levitation [CF-HL] or full magnetic levitation [CF-FML]). The primary outcome was 1-year survival assessed by 3 statistical methodologies (multivariable regression, propensity score matching, and instrumental variable analysis). RESULTS: Of 4448 patients, 2012 (45.2%) received the CF-HL and 2436 (54.8%) received the CF-FML. One-year survival for the CF-FML was 88% vs 79% for the CF-HL (overall P < .001), with a hazard ratio for mortality of 3.18 for the CF-HL (P < .0001) after risk adjustment. With propensity score matching (n = 1400 each cohort), 1-year survival was 87% for the CF-FML vs 80% for the CF-HL, with a hazard ratio of 3.20 for mortality with the CF-HL (P < .0001) after risk adjustment. With an instrumental variable analysis, the probability of receiving the CF-HL was associated with a hazard ratio of 3.11 (P < .0001). CONCLUSIONS: Statistical methodology using propensity score matching and instrumental variable analysis increased the robustness of observations derived from real-world data and demonstrates the feasibility of performing comparative effectiveness research using STS Intermacs. These analyses provide additional evidence supporting a survival benefit of the CF-FML vs CF-HL.

The Society of Thoracic Surgeons Intermacs 2019 Annual Report: The Changing Landscape of Devices and Indications.

BACKGROUND: The field of mechanical circulatory support has been impacted by the approval of new continuous-flow left ventricular assist devices (LVADs) and changes to the United States heart allocation system. METHODS: Primary isolated continuous-flow LVAD implants in The Society of Thoracic Surgeons Intermacs registry from January 2014 through September 2019 were evaluated. Survival and freedom from major adverse events were compared between axial-flow, centrifugal-flow with hybrid levitation (CF-HL), and centrifugal-flow with full magnetic levitation (CF-FML) devices. RESULTS: Of 2603 devices implanted in 2014, 1824 (70.1%) were axial flow and 1213 (46.6%) were destination therapy (DT); through September 2019, 1752 devices were implanted, but only 37 (2.1%) were axial flow and 1230 (70.2%) were DT. Implants were performed in 13,016 patients between 2014 and 2018. Patients receiving implants in 2017-2018 compared with 2014-2016 were more likely to be at Intermacs profile 1 (17.1% vs 14.3%, P < .001) and to have preimplant temporary mechanical circulatory support (34.8% vs 29.3%, P < .001). Overall survival and freedom from major adverse events were higher with CF-FML devices. In multivariable analysis of survival between CF-HL and CF-FML, device type was not a significant early hazard, but the use of CF-HL devices had a late hazard ratio for death of 3.01 (P < .001). CONCLUSIONS: Over the past 5 years, centrifugal-flow LVADs have become the dominant technology and DT the most common implant strategy. While outcomes with CF-FML devices are promising, comparisons with other devices from nonrandomized registry studies should be made with caution.

Survival Outcomes After Heart Transplantation: Does Recipient Sex Matter?

BACKGROUND: Currently, women represent <25% of heart transplant recipients. Reasons for this female underrepresentation have been attributed to selection and referral bias and potentially poorer outcomes in female recipients. The aim of this study was to compare long-term posttransplant survival between men and women, when matched for recipient and donor characteristics. METHODS AND RESULTS: Using the International Society for Heart and Lung Transplantation Registry, we performed descriptive analyses and estimated overall freedom from posttransplant death stratified by sex using Kaplan-Meier survival methods. Male and female recipients were matched according to the Index for Mortality Prediction After Cardiac Transplantation and Donor Risk Index score using 1:1 propensity score matching. The study cohort comprised 34 198 heart transplant recipients (76.3% men, 23.7% women) between 2004 and 2014. Compared with men, women were more likely younger (51 [39-59] versus 55 [46-61] years; P<0.001) and had a different distribution of heart failure etiology (P<0.001). In general, the prevalence of comorbidities was lower in women than in men. Women were less likely to have diabetes mellitus (19.1% versus 26.2%; P<0.001), hypertension (40.7% versus 47.9%; P<0.001), peripheral vascular disease (2.4% versus 3.3%; P=0.002), tobacco use (36.5% versus 52.3%; P<0.001), and prior cardiovascular surgery (38.6% versus 50.7%; P<0.001). Women were more likely to have a history of malignancy (10.5% versus 5.3%; P<0.001), require intravenous inotropes (41.4% versus 37.2%; P<0.001), and were less likely supported by an intra-aortic balloon pump (3.3% versus 3.8%; P=0.03) or durable ventricular assist device (22% versus 31.5%; P<0.001). Transplanted male recipients had a higher Index for Mortality Prediction After Cardiac Transplantation score (5 [2-7] versus 4 [1-6]; P<0.001). When male and female heart transplant recipients were matched for recipient and donor characteristics, there was no significant survival difference (P=0.57). CONCLUSIONS: Overall survival does not differ between men and women after cardiac transplantation. Women who survive to heart transplantation appear to have lower risk features than male recipients but receive hearts from higher risk donors.

Outcomes in patients undergoing cardiac retransplantation: A propensity matched cohort analysis of the UNOS Registry.

BACKGROUND: Cardiac retransplantation accounts for approximately 3% of cardiac transplantation and is considered a risk factor for increased mortality. However, factors inherent to retransplantation including previous sternotomy, sensitization, and renal dysfunction may account for the increased mortality. We assessed whether retransplantation was associated with all-cause mortality after adjusting for such patient risk factors. METHODS: We conducted a retrospective cohort study of adult and pediatric patients enrolled in the United Network for Organ Sharing database. We identified patients undergoing cardiac retransplantation based on transplant listing diagnosis and history of previous transplant. We used propensity-score matching to identify a matched cohort undergoing initial heart transplantation. RESULTS: In total, 62,112 heart transplant recipients were identified, with a mean age 46.6 ± 19.1 years. Of these, 2,202 (3.4%) underwent late cardiac retransplantation (>1 year after initial transplant and not for acute rejection). Compared with a matched group of patients undergoing initial heart transplantation, patients undergoing late retransplantation had comparable rates of all-cause mortality at 1 year (13.6% vs 13.8%, p = 0.733). In addition, overall mortality was not significantly different after matching (unadjusted hazard ratio [HR] 1.08, p = 0.084). In contrast, patients undergoing retransplantation within 1 year of initial transplant or for acute rejection remained at increased risk of mortality post-transplant after similar matching (unadjusted HR 1.79, p < 0.001). CONCLUSIONS: After matching for comorbidities, late retransplantation in the adult population was not associated with an increase in all-cause mortality. Our findings highlight the importance of assessing indication acuity and comorbid conditions when considering retransplant candidacy.

A novel therapy for an unusual problem: IL-1 receptor antagonist for recurrent post-transplant pericarditis.

Heart transplant (HTx) recipients are at increased risk of pericardial disease. Idiopathic recurrent pericarditis has not been previously described following HTx. We describe a 35-year-old male who was admitted with pericarditis and moderate pericardial effusion 10 months after HTx. Two weeks before his admission, his prednisone had been tapered off. A thorough infectious workup and endomyocardial biopsy was unrevealing. He was started on colchicine with the addition of tapering prednisone regimen of 40 mg daily due to unresolved pain. Over the next several years, he had three recurrent episodes of pericarditis requiring re-initiation of prednisone with extensive investigations negative for rejection, autoimmune, and infectious causes. Cardiac MRI confirmed pericardial inflammation. Due to his recurrent course and inability to wean off prednisone, anakinra, an IL-1 receptor antagonist, was started at 100 mg sc daily. This allowed successful discontinuation of prednisone. He is now 34 months post-transplant without recurrence on anakinra and colchicine maintenance. Due to the overlap between idiopathic recurrent pericarditis and auto-inflammatory diseases, there is growing evidence for utilizing IL-1 receptor antagonists in this condition. While pericarditis is common in the HTx population, this is the first report of successful use of an IL-1 receptor blocker for pericarditis in this population.

The Society of Thoracic Surgeons Intermacs Database Annual Report: Evolving Indications, Outcomes, and Scientific Partnerships.

BACKGROUND: The Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs), a joint effort among the National Heart, Lung, and Blood Institute, the Food and Drug Administration, the Centers for Medicare and Medicaid Services, and others, was established in 2005 at the University of Alabama at Birmingham. The registry examined clinical outcomes and quality-of-life metrics of patients who received an Food and Drug Administration-approved durable mechanical circulatory support (MCS) device to treat advanced heart failure. On January 1, 2018, the Intermacs Database became part of The Society of Thoracic Surgeons National Database, providing additional resources for quality assessment and improvement and scientific advancement. METHODS: The Intermacs Database Annual Report summarizes outcomes in patients (≥19 years of age) who underwent durable MCS implant between June 23, 2006, and December 31, 2017. Outcomes are presented for patients who underwent isolated continuous flow left ventricular assist device (CF LVAD) support, CF LVAD support with concomitant right ventricular assist device (RVAD) implant, or total artificial heart implant. Analyses of patients with CF LVADs are stratified by axial flow and centrifugal flow configurations. Because of the association of era with outcomes, the survival analyses are restricted to isolated CF LVADs implanted in the 2012 to 2016 era. RESULTS: There were 25,145 adult patients with MCS reported to Intermacs, of whom 18,539 (74%) received CF LVADs, 667 (2.6%) had an RVAD with CF LVAD, 339 received a total artificial heart (1.3%), and 20 (0.07%) received an isolated RVAD. Of the CF LVADs, mean age was 57 ± 1 years, 26% were listed for transplantation, and 51% were in cardiogenic shock (profile 1 to 2) preoperatively. CF LVADs included 14,527 axial flow (78%) and 4,012 centrifugal flow (22%) devices. Intermacs patient phenotype has evolved over time to include more patients with profile 3 (26% in 2006 to 2011 versus 35% in 2012 to 2016) and fewer patients with profile 2 (40% versus 35%), patients with better markers of preoperative renal and hepatic function, and more patients who received implants for destination therapy (29% versus 48%) indication. In 2017, centrifugal flow implants (51%) approximated that of axial flow devices (49%). Mean CF LVAD support duration was 20 months (31,563 patient-years). One-year survival for isolated CF LVADs was 83% and 5-year survival was 46%. One-year survivals for centrifugal versus axial flow devices were 85% and 84%, respectively. Patients who required concomitant RVAD support had 1- and 5-year survivals of 58% and 28%, respectively. Freedom from all-cause readmission was 70% at 1 month and 20% at 1 year. At 1 year, stroke occurred in 20% of patients on centrifugal flow and 13% of patients on axial flow support (p < 0.001), gastrointestinal bleeding affected 20% of patients with centrifugal flow devices and 25% of patients with axial flow devices (p < 0.001), and pump-related infection occurred in 28% of patients with centrifugal flow devices versus 25% of patients with axial flow devices (p = 0.01). Neurologic dysfunction (19% of deaths) and multisystem organ dysfunction (15%) were the most common causes of death. CONCLUSIONS: With the evolution of MCS, patient phenotype and outcomes are also changing over time. CF LVAD support is increasingly being used in the less ill patient phenotype and more patients are supported for destination therapy. Mean survival is now approaching 5 years, but adverse events, especially neurologic events, continue to have a detrimental impact on the success of CF LVAD support.

The Society of Thoracic Surgeons Intermacs database annual report: Evolving indications, outcomes, and scientific partnerships.

BACKGROUND: The Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs), a joint effort among the National Heart, Lung, and Blood Institute, the Food and Drug Administration, the Centers for Medicare and Medicaid Services, and others, was established in 2005 at the University of Alabama at Birmingham. The registry examined clinical outcomes and quality-of-life metrics of patients who received an Food and Drug Administration-approved durable mechanical circulatory support (MCS) device to treat advanced heart failure. On January 1, 2018, the Intermacs Database became part of The Society of Thoracic Surgeons National Database, providing additional resources for quality assessment and improvement and scientific advancement. METHODS: The Intermacs Database Annual Report summarizes outcomes in patients (≥19 years of age) who underwent durable MCS implant between June 23, 2006, and December 31, 2017. Outcomes are presented for patients who underwent isolated continuous flow left ventricular assist device (CF LVAD) support, CF LVAD support with concomitant right ventricular assist device (RVAD) implant, or total artificial heart implant. Analyses of patients with CF LVADs are stratified by axial flow and centrifugal flow configurations. Because of the association of era with outcomes, the survival analyses are restricted to isolated CF LVADs implanted in the 2012 to 2016 era. RESULTS: There were 25,145 adult patients with MCS reported to Intermacs, of whom 18,539 (74%) received CF LVADs, 667 (2.6%) had an RVAD with CF LVAD, 339 received a total artificial heart (1.3%), and 20 (0.07%) received an isolated RVAD. Of the CF LVADs, mean age was 57 ± 1 years, 26% were listed for transplantation, and 51% were in cardiogenic shock (profile 1 to 2) preoperatively. CF LVADs included 14,527 axial flow (78%) and 4,012 centrifugal flow (22%) devices. Intermacs patient phenotype has evolved over time to include more patients with profile 3 (26% in 2006 to 2011 versus 35% in 2012 to 2016) and fewer patients with profile 2 (40% versus 35%), patients with better markers of preoperative renal and hepatic function, and more patients who received implants for destination therapy (29% versus 48%) indication. In 2017, centrifugal flow implants (51%) approximated that of axial flow devices (49%). Mean CF LVAD support duration was 20 months (31,563 patient-years). One-year survival for isolated CF LVADs was 83% and 5-year survival was 46%. One-year survivals for centrifugal versus axial flow devices were 85% and 84%, respectively. Patients who required concomitant RVAD support had 1- and 5-year survivals of 58% and 28%, respectively. Freedom from all-cause readmission was 70% at 1 month and 20% at 1 year. At 1 year, stroke occurred in 20% of patients on centrifugal flow and 13% of patients on axial flow support (p < 0.001), gastrointestinal bleeding affected 20% of patients with centrifugal flow devices and 25% of patients with axial flow devices (p < 0.001), and pump-related infection occurred in 28% of patients with centrifugal flow devices versus 25% of patients with axial flow devices (p = 0.01). Neurologic dysfunction (19% of deaths) and multisystem organ dysfunction (15%) were the most common causes of death. CONCLUSIONS: With the evolution of MCS, patient phenotype and outcomes are also changing over time. CF LVAD support is increasingly being used in the less ill patient phenotype and more patients are supported for destination therapy. Mean survival is now approaching 5 years, but adverse events, especially neurologic events, continue to have a detrimental impact on the success of CF LVAD support.

Risk evaluation using gene expression screening to monitor for acute cellular rejection in heart transplant recipients.

BACKGROUND: Gene expression profiling (GEP) was developed for non-invasive surveillance of acute cellular rejection. Despite its widespread use, there has been a paucity in outcome data for patients managed with GEP outside of clinical trials. METHODS: The Outcomes AlloMap Registry (OAR) is an observational, prospective, multicenter study including patients aged ≥ 15 years and ≥ 55 days post-cardiac transplant. Primary outcome was death and a composite outcome of hemodynamically significant rejection, graft dysfunction, retransplantation, or death. Secondary outcomes included readmission rates and development of coronary allograft vasculopathy and malignancies. RESULTS: The study included 1,504 patients, who were predominantly Caucasian (69%), male (74%), and aged 54.1 ± 12.9 years. The prevalence of moderate to severe acute cellular rejection (≥2R) was 2.0% from 2 to 6 months and 2.2% after 6 months. In the OAR there was no association between higher GEP scores and coronary allograft vasculopathy (p = 0.25), cancer (p = 0.16), or non-cytomegalovirus infection (p = 0.10). Survival at 1, 2, and 5 years post-transplant was 99%, 98%, and 94%, respectively. The composite outcome occurred in 103 patients during the follow-up period. GEP scores in dual-organ recipients (heart-kidney and heart-liver) were comparable to heart-alone recipients. CONCLUSIONS: This registry comprises the largest contemporary cohort of patients undergoing GEP for surveillance. Among patients selected for GEP surveillance, survival is excellent, and rates of acute rejection, graft dysfunction, readmission, and death are low.

Planned Concomitant Left and Right Ventricular Assist Device Insertion to Avoid Long-term Biventricular Mechanical Support: Bridge to Right Ventricular Recovery.

INTRODUCTION: The planned use of a temporary right ventricular assist device (RVAD) at the time of left ventricular assist device (LVAD) implantation may prevent the need for a permanent biventricular assist device (BiVAD). Herein we describe our RVAD weaning protocol that was effectively employed in 4 patients to prevent the need for permanent BiVAD. METHODS: Four patients in refractory cardiogenic shock underwent planned RVAD insertion during LVAD implantation due to severely depressed right ventricular function with dilation preoperatively. A standardized RVAD weaning protocol was employed in these 4 patients in preparation for decannulation. RESULTS: Temporary RVADs were successfully placed in all 4 patients at the time of LVAD implantation. All patients survived to RVAD decannulation and discharge and were alive at the time of most recent follow-up (range, 528-742 days post-RVAD decannulation). CONCLUSION: Planned implantation of a temporary RVAD in high risk patients may avoid the need for biventricular mechanical support in the future.

A Bayesian Model to Predict Survival After Left Ventricular Assist Device Implantation.

OBJECTIVES: This study investigates the use of a Bayesian statistical models to predict survival at various time points in patients undergoing left ventricular assist device (LVAD) implantation. BACKGROUND: LVADs are being increasingly used in patients with end-stage heart failure. Appropriate patient selection continues to be key in optimizing post-LVAD outcomes. METHODS: Data used for this study were derived from 10,277 adult patients from the INTERMACS (Inter-Agency Registry for Mechanically Assisted Circulatory Support) who had a primary LVAD implanted between January 2012 and December 2015. Risk for mortality was calculated retrospectively for various time points (1, 3, and 12 months) after LVAD implantation, using multiple pre-implantation variables. For each of these endpoints, a separate tree-augmented naïve Bayes model was constructed using the most predictive variables. RESULTS: A set of 29, 26, and 31 pre-LVAD variables were found to be predictive at 1, 3, and 12 months, respectively. Predictors of 1-month mortality included low Inter-Agency Registry for Mechanically Assisted Circulatory Support profile, number of acute events in the 48 h before surgery, temporary mechanical circulatory support, and renal and hepatic dysfunction. Variables predicting 12-month mortality included advanced age, frailty, device strategy, and chronic renal disease. The accuracy of all Bayesian models was between 76% and 87%, with an area under the receiver operative characteristics curve of between 0.70 and 0.71. CONCLUSIONS: A Bayesian prognostic model for predicting survival based on the comprehensive INTERMACS registry provided highly accurate predictions of mortality based on pre-operative variables. These models may facilitate clinical decision-making while screening candidates for LVAD therapy.

Clinical experience with temporary right ventricular mechanical circulatory support.

OBJECTIVES: This study sought to determine if indication for support affects the outcomes after temporary right ventricular mechanical circulatory support after postcardiotomy cardiogenic shock, cardiac transplant, or left ventricular assist device placement. METHODS: A retrospective review was performed on 80 patients receiving a right ventricular assist device. Data were collected from a prospectively maintained database. Kaplan-Meier survival analysis was performed to compare survival between groups. Multivariate regression analysis was performed to identify risk factors for failure to wean from support. RESULTS: The indication for support was postcardiotomy cardiogenic shock in 13 patients (16%), cardiac transplant in 25 patients (31%), and left ventricular assist device in 42 patients (53%). Median support time was 6 days. Device was successfully weaned in 6 postcardiotomy cardiogenic shock cases (46%), 21 cardiac transplant cases (84%), and 35 left ventricular assist device cases (83%). Survival was worse for patients with postcardiotomy cardiogenic shock compared with patients with a left ventricular assist device. Survival up to 3 months was better for patients who received immediate (n = 43) versus delayed (n = 37) support (79% vs 46%, P = .003). Weaning and survival remained static across implant era. Risk factor analysis identified postcardiotomy cardiogenic shock indication (odds ratio, 0.161; P = .007; confidence interval, 0.043-0.600) as an independent negative predictor of weaning from mechanical support. CONCLUSIONS: Temporary right ventricular mechanical support remains an effective treatment strategy after left ventricular assist device placement with immediate support resulting in superior short-term survival. Caution should be applied in postcardiotomy cardiogenic shock when weaning and survival are poor. Overall survival outcomes have remained relatively static over time.

Early Right Ventricular Assist Device Use in Patients Undergoing Continuous-Flow Left Ventricular Assist Device Implantation: Incidence and Risk Factors From the Interagency Registry for Mechanically Assisted Circulatory Support.

BACKGROUND: To investigate preimplant risk factors associated with early right ventricular assist device (RVAD) use in patients undergoing continuous-flow left ventricular assist device (LVAD) surgery. METHODS AND RESULTS: Patients in the Interagency Registry for Mechanically Assisted Circulatory Support who underwent primary continuous-flow-LVAD surgery were examined for concurrent or subsequent RVAD implantation within 14 days of LVAD. Risk factors for RVAD implantation and the combined end point of RVAD or death within 14 days of LVAD were assessed with stepwise logistic regression. We compared survival between patients with and without RVAD using Kaplan-Meier method and Cox proportional hazards modeling. Of 9976 patients undergoing continuous-flow-LVAD implantation, 386 patients (3.9%) required an RVAD within 14 days of LVAD surgery. Preimplant characteristics associated with RVAD use included interagency registry for mechanically assisted circulatory support patient profiles 1 and 2, the need for preoperative extracorporeal membrane oxygenation or renal replacement therapy, severe preimplant tricuspid regurgitation, history of cardiac surgery, and concomitant procedures other than tricuspid valve repair at the time of LVAD. Hemodynamic determinants included elevated right atrial pressure, reduced pulmonary artery pulse pressure, and reduced stroke volume. The final model demonstrated good performance for both RVAD implant (area under the curve, 0.78) and the combined end point of RVAD or death within 14 days (area under the curve, 0.73). Compared with patients receiving an isolated LVAD, patients requiring RVAD had decreased 1- and 6-month survival: 78.1% versus 95.8% and 63.6% versus 87.9%, respectively (P<0.0001 for both). CONCLUSIONS: The need for RVAD implantation after LVAD is associated with indices of global illness severity, markers of end-organ dysfunction, and profiles of hemodynamic instability.

Left Ventricular Assist Devices for Lifelong Support.

Continuous-flow left ventricular assist devices (LVADs) have revolutionized advanced heart failure care. These compact, fully implantable heart pumps are capable of providing meaningful increases in survival, functional capacity, and quality of life. Implantation volumes continue to grow, but several challenges remain to be overcome before LVADs will be considered as the therapy of choice for all patients with advanced heart failure. They must be able to consistently extend survival for the long term (7 to 10 years), rather than the midterm (3 to 5 years) more typical of contemporary devices; they must incorporate design elements that reduce shear stress and avoid stasis to reduce the frequent adverse events of bleeding, stroke, and pump thrombosis; and they must become more cost-effective. The advancements in engineering, implantation technique, and medical management detailed in this review will highlight the progress made toward achieving lifelong LVAD support and the challenges that remain.

Preoperative liver dysfunction influences blood product administration and alterations in circulating haemostatic markers following ventricular assist device implantation.

OBJECTIVES: Preoperative liver dysfunction may influence haemostasis following ventricular assist device (VAD) implantation. The Model for End-stage Liver Disease (MELD) score was assessed as a predictor of bleeding and levels of haemostatic markers in patients with currently utilized VADs. METHODS: Sixty-three patients (31 HeartMate II, 15 HeartWare, 17 Thoratec paracorporeal ventricular assist device) implanted 2001-11 were analysed for preoperative liver dysfunction (MELD) and blood product administration. Of these patients, 21 had additional blood drawn to measure haemostatic marker levels. Cohorts were defined based on high (≥18.0, n = 7) and low (<18.0, n = 14) preoperative MELD scores. RESULTS: MELD score was positively correlated with postoperative administration of red blood cell (RBC), platelet, plasma and total blood product units (TBPU) , as well as chest tube drainage and cardiopulmonary bypass time. Age and MELD were preoperative predictors of TBPU by multivariate analysis. The high-MELD cohort had higher administration of TBPU, RBC and platelet units and chest tube drainage postimplant. Similarly, patients who experienced at least one bleeding adverse event were more likely to have had a high preoperative MELD. The high-MELD group exhibited different temporal trends in F1 + 2 levels and platelet counts to postoperative day (POD) 55. D-dimer levels in high-MELD patients became elevated versus those for low-MELD patients on POD 55. CONCLUSIONS: Preoperative MELD score predicts postoperative bleeding in contemporary VADs. Preoperative liver dysfunction may also alter postoperative subclinical haemostasis through different temporal trends of thrombin generation and platelet counts, as well as protracted fibrinolysis.

Cost-effectiveness of routine surveillance endomyocardial biopsy after 12 months post-heart transplantation.

BACKGROUND: Despite low risk of late rejection after heart transplant (HT), surveillance endomyocardial biopsies (EMBs) are often continued for years. We assessed the cost-effectiveness of routine EMB after 12 months post-HT. METHODS AND RESULTS: Markov model compared the following surveillance EMB strategies to baseline strategy of stopping EMB 12 months post-HT: (1) every 4 months during year 2 post-HT, (2) every 6 months during year 2, (3) every 4 months for years 2 to 3, and (4) every 6 months for years 2 to 3. Patients entered the model 12 months post-HT and were followed until 36 months. In all strategies, patients had EMB with symptoms; in biopsy strategies after 12 months, EMB was also performed as scheduled regardless of symptoms. One-way and Monte Carlo sensitivity analyses were performed. Stopping EMB at 12 months was dominant (more effective, less costly), saving $2884 per patient compared with the next best strategy (every 6 months for year 2) and gaining 0.0011 quality-adjusted life-years. Increasing the annual risk of asymptomatic rejection in years 2 to 3 from previously reported 2.5% to 8.5% resulted in the biopsy every 6 months for year 2 strategy gaining 0.0006 quality-adjusted life-years, but cost $4 913 599 per quality-adjusted life-year gained. EMB for 12 months was also no longer dominant when mortality risk from untreated asymptomatic rejection approached 11%; competing strategies still cost >$200 000 per quality-adjusted life-year as that risk approached 99%. CONCLUSIONS: Surveillance EMB for 12 months post-HT is more effective and less costly than EMB performed after 12 months, unless risks of asymptomatic cellular rejection and its mortality are strikingly higher than previously observed.

Utility of gene expression profiling score variability to predict clinical events in heart transplant recipients.

BACKGROUND: Gene expression profiling test scores have primarily been used to identify heart transplant recipients who have a low probability of rejection at the time of surveillance testing. We hypothesized that the variability of gene expression profiling test scores within a patient may predict risk of future events of allograft dysfunction or death. METHOD: Patients from the IMAGE study with rejection surveillance gene expression profiling tests performed at 1- to 6-month intervals were selected for this cohort study. Gene expression profiling score variability was defined as the standard deviation of an individual's cumulative test scores. Gene expression profiling ordinal score (range, 0-39), threshold score (binary value=1 if ordinal score ≥ 34), and score variability were studied in multivariate Cox regression models to predict future clinical events. RESULTS: Race, age at time of transplantation, and time posttransplantation were significantly associated with future events in the univariate analysis. In the multivariate analyses, gene expression profiling score variability, but not ordinal scores or scores over threshold, was independently associated with future clinical events. The regression coefficient P values were <0.001, 0.46, and 0.773, for gene expression profiling variability, ordinal, and threshold scores, respectively. The hazard ratio for a 1 unit increase in variability was 1.76 (95% CI, 1.4-2.3). DISCUSSION: The variability of a heart recipient's gene expression profiling test scores over time may provide prognostic utility. This information is independent of the probability of acute cellular rejection at the time of testing that is rendered from a single ordinal gene-expression profiling test score.