Feasibility of a Composite Measure of Pulmonary Vascular Impedance and Application to Patients with Chronic RV Failure Post LVAD Implant

Pulmonary vascular impedance (PVZ) describes RV afterload in the frequency domain and has not been studied extensively in LVAD patients. We sought to determine (1) feasibility of calculating a composite (c)PVZ using standard of care (SoC), asynchronous, pulmonary artery pressure (PAP) and flow (PAQ) waveforms; and (2) if chronic right ventricular failure (RVF) post-LVAD implant was associated with changes in perioperative cPVZ.PAP and PAQ were obtained via SoC procedures at three landmarks: T(1), Retrospectively, pre-operative with patient conscious; and T(2) and T(3), prospectively with patient anesthetized, and either pre-sternotomy or chest open with LVAD, respectively. Additional PAP's were taken at T(4), following chest closure; and T(5), 4-24 h post chest closure. Harmonics (z) were calculated by Fast Fourier Transform (FFT) with cPVZ(z) = FFT(PAP)/FFT(PAQ). Total pulmonary resistance Z(0); characteristic impedance Zc, mean of cPVZ(2-4); and vascular stiffness PVS, sum of cPVZ(1,2), were compared at T(1,2,3) between +/-RVF groups.Out of 51 patients, nine experienced RVF. Standard hemodynamics and changes in cPVZ-derived parameters were not significant between groups at any T.In conclusion, cPVZ calculated from SoC measures is possible. Although data that could be obtained were limited it suggests no difference in RV afterload for RVF patients post-implant. If confirmed in larger studies, focus should be placed on cardiac function in these subjects.

Hospitalization Patterns and Impact of a Magnetically-Levitated Left Ventricular Assist Device in the MOMENTUM 3 Trial

BACKGROUND

In the MOMENTUM 3 (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy with HeartMate 3) pivotal trial, the HeartMate 3 (HM3) fully magnetically levitated left ventricular assist device (LVAD) demonstrated superiority over the axial-flow HeartMate II (HMII) LVAD. The patterns and predictors of hospitalizations with the HM3 LVAD have not been characterized.

OBJECTIVES

This study sought to determine causes, predictors, and impact of hospitalizations during LVAD support.

METHODS

Patients discharged after LVAD implantation were analyzed. In the pivotal trial, 485 recipients of HM3 were compared with 471 recipients of HMII. The pivotal trial HM3 group was also compared to 949 recipients of HM3 in the postapproval phase within the trial portfolio. Predictors of cause-specific rehospitalization were analyzed.

RESULTS

The rates of rehospitalization were lower with HM3 LVAD than with HMII LVAD in the pivotal trial (225.7 vs 246.4 events per 100 patient-years; P < 0.05). Overall, rehospitalization rates and duration were similar in the HM3 postapproval phase and pivotal trial but prolonged hospitalizations (>7 days) were less frequent (rate ratio: 0.90 [95% CI: 0.80-0.98]; P < 0.05). In HM3 recipients, the most frequent causes of rehospitalization included infection, heart failure (HF)-related events, and bleeding. First rehospitalization caused by HF-related event versus other causes was associated with reduced survival (HR: 2.2 [95% CI: 1.3-3.9]; P = 0.0014). Male sex, non-White race, presence of cardiac resynchronization therapy/implantable cardioverter-defibrillator, obesity, higher right atrial pressure, smaller LV size, longer duration of index hospitalization, and lower estimated glomerular filtration rate at index discharge predicted HF hospitalizations.

CONCLUSIONS

Contemporary support with the HM3 fully magnetically levitated LVAD is associated with a lower hospitalization burden than with prior pumps; however, rehospitalizations for infection, HF, and bleeding remain important challenges for progress in the patient journey. (MOMENTUM 3 IDE Clinical Study, NCT02224755; MOMENTUM 3 Continued Access Protocol [MOMENTUM 3 CAP], NCT02892955).

Center Variability in Patient Outcomes Following HeartMate 3 Implantation: An Analysis of the MOMENTUM 3 Trial

BACKGROUND

As left ventricular assist device (LVAD) survival rates continue to improve, evaluating site-specific variability in outcomes can facilitate identifying targets for quality-improvement initiative opportunities in the field.

METHODS

Deidentified center-specific outcomes were analyzed for HeartMate 3 (HM3) patients enrolled in the MOMENTUM 3 pivotal and continued access protocol trials. Centers < 25th percentile for HM3 volumes were excluded. Variability in risk-adjusted center mortality was assessed at 90 days and 2 years (conditional upon 90-day survival). Adverse event (AE) rates were compared across centers.

RESULTS

In the 48 included centers (1958 patients), study-implant volumes ranged between 17 and 106 HM3s. Despite similar trial-inclusion criteria, patient demographics varied across sites, including age quartile ((Q)1-Q3:57-62 years), sex (73%-85% male), destination therapy intent (60%-84%), and INTERMACS profile 1-2 (16%-48%). Center mortality was highly variable, nadiring at ≤ 3.6% (≤ 25th percentile) and peaking at ≥ 10.4% (≥ 75th percentile) at 90 days and ≤ 10.2% and ≥ 18.7%, respectively, at 2 years. Centers with low mortality rates tended to have lower 2-year AE rates, but no center was a top performer for all AEs studied.

CONCLUSIONS

Mortality and AEs were highly variable across MOMENTUM 3 centers. Studies are needed to improve our understanding of the drivers of outcome variability and to ascertain best practices associated with high-performing centers across the continuum of intraoperative to chronic stages of LVAD support.

Outcomes With Phosphodiesterase-5 Inhibitor Use After Left Ventricular Assist Device: An STS-INTERMACS Analysis

BACKGROUND

Elevated right ventricular afterload following continuous-flow left ventricular assist device (CF-LVAD) may contribute to late right heart failure (LRHF). PDE5i (phosphodiesterase-5 inhibitors) are used to treat pulmonary hypertension and right heart dysfunction after CF-LVAD, but their impact on outcomes is uncertain.

METHODS

We queried Interagency Registry for Mechanically Assisted Circulatory Support from 2012 to 2017 for adults receiving a primary CF-LVAD and surviving ≥30 days from index discharge. Patients receiving early PDE5i (ePDE5i) at 1 month were propensity-matched 1:1 with controls. The primary outcome was the cumulative incidence of LRHF, defined using prevailing Interagency Registry for Mechanically Assisted Circulatory Support criteria; secondary outcomes included all-cause mortality and major bleeding.

RESULTS

Among 9627 CF-LVAD recipients analyzed, 2463 (25.6%) received ePDE5i and 1600 were propensity-matched 1:1 with controls. Before implant, ePDE5i patients had more severe RV dysfunction (13.1% versus 9.6%) and higher pulmonary vascular resistance (2.8±2.7 versus 2.2±2.4 WU), both P<0.001, but clinical factors were well-balanced after propensity-matching. In the unmatched cohort, ePDE5i patients had a higher 3-year cumulative incidence of LRHF, mortality, and major bleeding, but these differences were attenuated in the propensity-matched cohort: LRHF 40.8% versus 35.7% (hazard ratio, 1.14 [95% CI, 0.99-1.32]; P=0.07); mortality 38.6% versus 35.8% (hazard ratio, 0.99 [95% CI, 0.86-1.15]; P=0.93); major bleeding 51.2% versus 46.0% (hazard ratio, 1.12 [95% CI, 0.99-1.27]; P=0.06).

CONCLUSIONS

Compared with propensity-matched controls, adult CF-LVAD patients receiving ePDE5i had similar rates of LRHF, mortality, and major bleeding. While intrinsic patient risk factors likely account for more adverse outcomes with ePDE5i in the unmatched cohort, there is no obvious benefit of ePDE5i in the LVAD population.

Adipose-derived stem cell sheet under an elastic patch improves cardiac function in rats after myocardial infarction

OBJECTIVES

Although adipose-derived stem cells (ADSCs) have shown promise in cardiac regeneration, stable engraftment is still challenging. Acellular bioengineered cardiac patches have shown promise in positively altering ventricular remodeling in ischemic cardiomyopathy. We hypothesized that combining an ADSC sheet approach with a bioengineered patch would enhance ADSC engraftment and positively promote cardiac function compared with either therapy alone in a rat ischemic cardiomyopathy model.

METHODS

Cardiac patches were generated from poly(ester carbonate urethane) urea and porcine decellularized cardiac extracellular matrix. ADSCs constitutively expressing green fluorescent protein were established from F344 rats and transplanted as a cell sheet over the left ventricle 3 days after left anterior descending artery ligation with or without an overlying cardiac patch. Cardiac function was serially evaluated using echocardiography for 8 weeks, comparing groups with combined cells and patch (group C, n = 9), ADSCs alone (group A, n = 7), patch alone (group P, n = 6) or sham groups (n = 7).

RESULTS

Much greater numbers of ADSCs survived in the C versus A groups (P < .01). At 8 weeks posttransplant, the percentage fibrotic area was lower (P < .01) in groups C and P compared with the other groups and vasculature in the peri-infarct zone was greater in group C versus other groups (P < .01), and hepatocyte growth factor expression was higher in group C than in other groups (P < .05). Left ventricular ejection fraction was higher in group C versus other groups.

CONCLUSIONS

A biodegradable cardiac patch enhanced ADSC engraftment, which was associated with greater cardiac function and neovascularization in the peri-infarct zone following subacute myocardial infarction.

Primary Graft Dysfunction in Heart Transplant Recipients-Risk Factors and Longitudinal Outcomes

Before the 33rd Annual International Society for Heart and Lung Transplantation conference, there was significant intercenter variability in definitions of primary graft dysfunction (PGD). The incidence, risk factors, and outcomes of consensus-defined PGD warrant further investigation. We retrospectively examined 448 adult cardiac transplant recipients at our institution from 2005 to 2017. Patient and procedural characteristics were compared between PGD cases and controls. Multivariable logistic regression was used to model PGD and immediate postoperative high-inotrope requirement for hypothesized risk factors. Patients were followed for a mean 5.3 years to determine longitudinal mortality. The incidence of PGD was 16.5%. No significant differences were found with respect to age, sex, race, body mass index, predicted heart mass mismatch, pretransplant amiodarone therapy, or pretransplant mechanical circulatory support (MCS) between recipients with PGD versus no PGD. Each 10 minute increase in ischemic time was associated with 5% greater odds of PGD (OR = 1.05 [95% CI, 1.00-1.10]; p = 0.049). Pretransplant MCS, predicted heart mass mismatch ≥30%, and pretransplant amiodarone therapy were associated with high-immediate postoperative inotropic requirement. The 30 day, 1 year, and 5 year mortality for patients with PGD were 28.4%, 38.0%, and 45.8%, respectively, compared with 1.9%, 7.1%, and 21.5% for those without PGD (log-rank, p < 0.0001). PGD heralded high 30 day, 1 year, and 5 year mortality. Pretransplant MCS, predicted heart mass mismatch, and amiodarone exposure were associated with high-inotrope requirement, while prolonged ischemic time and multiple perioperative transfusions were associated with consensus-defined PGD, which may have important clinical implications under the revised United Network for Organ Sharing allocation system.

Graft Resistance Difference after HVAD to HeartMate 3 Left Ventricular Assist Device Exchange

BACKGROUND

A likely consequence of discontinued distribution and sale of the Medtronic HVAD™ System (HVAD) will be an increase in replacement with the Abbott HeartMate 3™ Left Ventricular Assist Device (HeartMate 3) when device exchange is necessary. If part or all if the HVAD 10 mm-diameter outflow graft is retained during replacement, the HeartMate 3 will have to run at a higher speed than it would with its 14 mm-diameter graft.

METHODS

A steady-state, in vitro study was run with 250 mm-long samples of HVAD, HeartMate 3, and half-HVAD/half-HeartMate 3 grafts and, additionally, 125 and 375 mm-long samples of HVAD graft. Flows of 3.0, 3.9, 4.3, 4.7, and 6.0 L/min were applied to encompass expected clinical conditions.

RESULTS

At typical and high flow rates of 4.3 and 6.0 L/min, HeartMate 3 rotor speeds with the full HVAD graft had to be increased relative to those with the HeartMate 3 graft from 5350 to 5700 and 6350 to 6900 rpm, respectively, with power consumption increases from 3.7 to 4.3 (16%) and 5.5 to 6.8 W (24%), respectively.

CONCLUSIONS

The study did not elucidate a severe consequence of utilizing remnant HVAD graft during pump exchange, but the incremental risks of a higher rotor speed, disadvantage to the patient in battery runtime, and the general benefit of complete conversion to the HeartMate 3 graft should be balanced against other procedural considerations. Complete graft replacement during HVAD-to-HeartMate 3 conversion remains the preferred approach from an engineering point of view.

Creation and Validation of a Novel Sex-Specific Mortality Risk Score in LVAD Recipients

Background

Prior studies have shown that women have worse 3‐month survival after receiving a left ventricular assist device compared with men. Currently used prognostic scores, including the Heartmate II Risk Score, do not account for the increased residual risk in women. We used the IMACS (International Society for Heart and Lung Transplantation Mechanically Assisted Circulatory Support) registry to create and validate a sex‐specific risk score for early mortality in left ventricular assist device recipients.

Methods and Results

Adult patients with a continuous‐flow LVAD from the IMACS registry were randomly divided into a derivation cohort (DC; n=9113; 21% female) and a validation cohort (VC; n=6074; 21% female). The IMACS Risk Score was developed in the DC to predict 3‐month mortality, from preoperative candidate predictors selected using the Akaike information criterion, or significant sex × variable interaction. In the DC, age, cardiogenic shock at implantation, body mass index, blood urea nitrogen, bilirubin, hemoglobin, albumin, platelet count, left ventricular end‐diastolic diameter, tricuspid regurgitation, dialysis, and major infection before implantation were retained as significant predictors of 3‐month mortality. There was significant ischemic heart failure × sex and platelet count × sex interaction. For each quartile increase in IMACS risk score, men (odds ratio [OR], 1.86; 95% CI, 1.74–2.00; P<0.0001), and women (OR, 1.93; 95% CI, 1.47–2.59; P<0.0001) had higher odds of 3‐month mortality. The IMACS risk score represented a significant improvement over Heartmate II Risk Score (IMACS risk score area under the receiver operating characteristic curve: men: DC, 0.71; 95% CI, 0.69–0.73; VC, 0.69; 95% CI, 0.66–0.72; women: DC, 0.73; 95% CI, 0.70–0.77; VC, 0.71 [95% CI, 0.66–0.76; P<0.01 for improvement in receiver operating characteristic) and provided excellent risk calibration in both sexes. Removal of sex‐specific interaction terms resulted in significant loss of model fit.

Conclusions

A sex‐specific risk score provides excellent risk prediction in LVAD recipients.

The Preimplantation Psychosocial Evaluation and Prediction of Clinical Outcomes During Mechanical Circulatory Support: What Information Is Most Prognostic?

BACKGROUND

Psychosocial evaluations are required for long-term mechanical circulatory support (MCS) candidates, no matter whether MCS will be destination therapy (DT) or a bridge to heart transplantation. Although guidelines specify psychosocial contraindications to MCS, there is no comprehensive examination of which psychosocial evaluation domains are most prognostic for clinical outcomes. We evaluated whether overall psychosocial risk, determined across all psychosocial domains, predicted outcomes, and which specific domains appeared responsible for any effects.

METHODS

A single-site retrospective analysis was performed for adults receiving MCS between April 2004 and December 2017. Using an established rating system, we coded psychosocial evaluations to identify patients at low, moderate, or high overall risk. We similarly determined risk within each of 10 individual psychosocial domains. Multivariable analyses evaluated whether psychosocial risk predicted clinical decisions about MCS use (DT versus bridge), and postimplantation mortality, transplantation, rehospitalization, MCS pump exchange, and standardly defined adverse medical events (AEs).

RESULTS

In 241 MCS recipients, greater overall psychosocial risk increased the likelihood of a DT decision (odds ratio, 1.76; P = 0.017); and postimplantation pump exchange and occurrence of AEs (hazard ratios [HRs] ≥ 1.25; P ≤ 0.042). The individual AEs most strongly predicted were cardiac arrhythmias and device malfunctions (HRs ≥ 1.39; P ≤ 0.032). The specific psychosocial domains predicting at least 1 study outcome were mental health problem severity, poorer medical adherence, and substance use (odds ratios and HRs ≥ 1.32; P ≤ 0.010).

CONCLUSIONS

The psychosocial evaluation predicts not only clinical decisions about MCS use (DT versus bridge) but important postimplantation outcomes. Strategies to address psychosocial risk factors before or soon after implantation may help to reduce postimplantation clinical risks.

Clinical outcomes and healthcare expenditures in the real world with left ventricular assist devices - The CLEAR-LVAD study

BACKGROUND

Several distinctly engineered left ventricular assist devices (LVADs) are in clinical use. However, contemporaneous real world comparisons have not been conducted, and clinical trials were not powered to evaluate differential survival outcomes across devices.

OBJECTIVES

Determine real world survival outcomes and healthcare expenditures for commercially available durable LVADs.

METHODS

Using a retrospective observational cohort design, Medicare claims files were linked to manufacturer device registration data to identify de-novo, durable LVAD implants performed between January 2014 and December 2018, with follow-up through December 2019. Survival outcomes were compared using a Cox proportional hazards model stratified by LVAD type and validated using propensity score matching. Healthcare resource utilization was analyzed across device types by using nonparametric bootstrap analysis methodology. Primary outcome was survival at 1-year and total Part A Medicare payments.

RESULTS

A total of 4,195 de-novo LVAD implants were identified in fee-for-service Medicare beneficiaries (821 HeartMate 3; 1,840 HeartMate II; and 1,534 Other-VADs). The adjusted hazard ratio for mortality at 1-year (confirmed in a propensity score matched analysis) for the HeartMate 3 vs HeartMate II was 0.64 (95% CI; 0.52-0.79, p< 0.001) and for the HeartMate 3 vs Other-VADs was 0.51 (95% CI; 0.42-0.63, p < 0.001). The HeartMate 3 cohort experienced fewer hospitalizations per patient-year vs Other-VADs (respectively, 2.8 vs 3.2 EPPY hospitalizations, p < 0.01) and 6.1 fewer hospital days on average (respectively, 25.2 vs 31.3 days, p < 0.01). The difference in Medicare expenditures, conditional on survival, for HeartMate 3 vs HeartMate II was -$10,722, p < 0.001 (17.4% reduction) and for HeartMate 3 vs Other-VADs was -$17,947, p < 0.001 (26.1% reduction).

CONCLUSIONS

In this analysis of a large, real world, United States. administrative dataset of durable LVADs, we observed that the HeartMate 3 had superior survival, reduced healthcare resource use, and lower healthcare expenditure compared to other contemporary commercially available LVADs.

Impact of Pre-Existing Mitral Regurgitation Following Left Ventricular Assist Device Implant

OBJECTIVES

Optimal management of significant mitral regurgitation (SMR) during left ventricular assist device (LVAD) placement remains uncertain. This study evaluates the effect of untreated preop SMR on outcomes following LVAD implant.

METHODS

Adults undergoing primary LVAD placement from April 2004 to May 2017 were included. Most recent preop transthoracic echocardiogram (TTE) was used to divide patients into an SMR group with moderate or greater regurgitation, and a group without SMR. Patients underwent LVAD implant without correction of SMR. Primary endpoint was 3-year postoperative survival, with secondary endpoints of length of stay (LOS), resolution of SMR following LVAD on postdischarge (30 day) TTE, and 1-year TTE.

RESULTS

LVAD placement was performed in 270 patients, 172 (63.7%) without SMR and 98 (36.3%) with SMR. There were no differences in comorbidities including diabetes, hypertension, and renal disease. Preop ejection fraction was similar, but a higher pulmonary vascular resistance was recorded in the SMR group (3.6 vs 3.0 Wood Units, P = 0.048). There was no difference in 3-year mortality between the 2 cohorts (log-rank P = 0.0.803). The SMR group had decreased LOS (median 19.5 vs 22 days, P = 0.009). Of the 98 SMR patients, 91 (92.9%) had resolution of SMR to less than moderate at 30 days. At 1 year, 15% of those with preoperative SMR had recurrent SMR.

CONCLUSIONS

Patients undergoing LVAD placement with preop SMR experience no differences in mortality, and a majority experience resolution of MR after implant. Longer-term SMR recurrence and need for mitral intervention with LVAD implant warrant further investigation.

A comparison of air-cell and gel surgical table pads and an evaluation of the influence of pressure distribution and other factors on pressure injury prevention

Guidelines for pressure injury prevention consider the use of pressure-redistributing pads to prevent tissue deformation. However, limited research exists to assess the pressure distribution provided by the operating tables and the effectiveness of pressure-redistributing pads in preventing pressure injuries. In this study, we compared the pressure distribution properties of two surgical table pads and identified parameters influencing pressure injury outcomes after a lengthy surgical procedure. Twenty-seven patients undergoing left ventricular assist device implantation surgery participated in the study. Participants were randomly assigned to use either an air cell-based pad or a gel pad. Interface pressure was recorded during the surgery. We analyzed the effect of surgical table pad type, interface pressure distribution and pressure injury outcomes and analyzed what characteristics of the patients and the interface pressure are most influential for the development of pressure injuries. Comparing the interface pressure parameters between the air-cell group and the gel group, only the peak pressure index x time was significantly different (p < 0.05). We used univariate logistic regression analysis to identify significant predictors for the pressure injury outcome. The support surface was not significant. And, among patient characteristics, only age and BMI were significant (p ≤ 0.05). Among the interface pressure parameters, pressure density maxima, peak pressure index x time, and coefficient of variation were significant for pressure injury outcome (p ≤ 0.05). Peak pressure index, average pressure, and the surgery length were not statistically significant for pressure injury outcomes.

Evaluation of a Health Care Performance Improvement Initiative to Facilitate Optimal Clinical Outcomes in Patients Receiving Ventricular Assist Device Support

BACKGROUND

Ventricular assist device (VAD) patients are at high risk for morbidities and mortality. One potentially beneficial component of the Joint Commission VAD Certification process is the requirement that individual VAD programs select 4 performance measures to improve and optimize patients' clinical outcomes.

PROBLEM STATEMENT

Review of patient data after our program's first certification visit in 2008 showed that, compared to national recommendations and published reports, our patients had suboptimal outcomes in 4 areas after device implantation: length of hospital stay, receipt of early (<48 hours) postsurgical physical therapy, driveline infection incidence, and adequacy of nutritional status (prealbumin ≥18 mg/dL).

METHODS

Plan-Do-Study-Act processes were implemented to shorten length of stay, increase patient receipt of early physical therapy, decrease driveline infection incidence, and improve nutritional status. With 2008 as our baseline, we deployed interventions for each outcome area across 2009 to 2017. Performance improvement activities included staff, patient, and family didactic, one-on-one, and hands-on education; procedural changes; and outcomes monitoring with feedback to staff on progress. Descriptive and inferential statistics were examined to document change in the outcomes.

OUTCOMES

Across the performance improvement period, length of stay decreased from 40 to 23 days; physical therapy consults increased from 87% to 100% of patients; 1-year driveline infection incidence went from 38% to 23.5%; and the percentage of patients with prealbumin within the normal range increased from 84% to 90%.

IMPLICATIONS

Performance improvement interventions may enhance ventricular assist device patient outcomes. Interventions' sustainability should be evaluated to ensure that gains are not lost over time.

Authorship Correction: Understanding and Addressing Variation in Health Care-Associated Infections After Durable Ventricular Assist Device Therapy: Protocol for a Mixed Methods Study

[This corrects the article DOI: 10.2196/14701.].

Understanding and Addressing Variation in Health Care-Associated Infections After Durable Ventricular Assist Device Therapy: Protocol for a Mixed Methods Study

BACKGROUND

Durable ventricular assist device (VAD) therapy is reserved for patients with advanced heart failure who have a poor estimated 1-year survival. However, despite highly protocolized management processes, patients are at a unique risk for developing a health care-associated infection (HAI). Few studies have examined optimal strategies for HAI prevention after durable VAD implantation, despite variability in rates across centers and their impact on short- and long-term outcomes.

OBJECTIVE

The objective of this study is to develop recommendations for preventing the most significant HAIs after durable VAD implantation. The study has 3 specific aims: (1) identify determinants of center-level variability in HAI rates, (2) develop comprehensive understanding of barriers and facilitators for achieving low center-level HAI rates, and (3) develop and disseminate a best practices toolkit for preventing HAIs that accommodates various center contexts.

METHODS

This is a sequential mixed methods study starting with a cross-sectional assessment of current practices. To address aim 1, we will conduct (1) a systematic review of HAI prevention studies and (2) in-depth quantitative analyses using administrative claims, in-depth clinical data, and organizational surveys of VAD centers. For aim 2, we will apply a mixed methods patient tracer assessment framework to conduct semistructured interviews, field observations, and document analysis informed by findings from aim 1 at 5 high-performing (ie, low HAIs) and 5 low-performing (ie, high HAI) centers, which will be examined using a mixed methods case series analysis. For aim 3, we will build upon the findings from the previous aims to develop and field test an HAI preventive toolkit, acquire stakeholder input at an annual cardiac surgical conference, disseminate the final version to VAD centers nationwide, and conduct follow-up surveys to assess the toolkit's adoption.

RESULTS

The project was funded by the Agency for Healthcare Research and Quality in 2018 and enrollment for the overall project is ongoing. Data analysis is currently under way and the first results are expected to be submitted for publication in 2019.

CONCLUSIONS

This mixed methods study seeks to quantitatively assess the determinants of HAIs across clinical centers and qualitatively identify the context-specific facilitators and barriers for attaining low HAI rates. The mixed data findings will be used to develop and disseminate a stakeholder-acceptable toolkit of evidence-based HAI prevention recommendations that will accommodate the specific contexts and needs of VAD centers.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/14701.

Challenges in the development and implementation of a healthcare system based extracorporeal cardiopulmonary resuscitation (ECPR) program for the treatment of out of hospital cardiac arrest

INTRODUCTION

Extracorporeal cardiopulmonary resuscitation (ECPR) can treat cardiac arrest refractory to conventional therapies. Many institutions are interested in developing their own ECPR program. However, there may be challenges in logistics and implementation.

AIMS

The aim of our protocol was to demonstrate that an ECPR team was feasible within our healthcare system and that the identification of UPMC Presbyterian as a receiving center allowed for successful treatment within 30 min from EMS dispatch.

METHODS

We developed out of hospital cardiac arrest (OHCA) ECPR protocols for Emergency Medical Services (EMS), EMS communications, and our in-hospital ECPR team. Inclusion criteria indentified patients with a potentially reversible arrest etiology and high probability of recoverable brain injury using a simple checklist: witnessed collapse, layperson CPR, initial shockable rhythm, and age 18-60 years. We trained local EMS crews to screen patients and reviewed the criteria with a Medic Command Physician prior to transport to our hospital.

RESULTS

From October 2015 to March 31st 2018, EMS treated 1165 EMS OHCA cases, transported 664 (57%) to a local hospital, and transported 120 (10%) to our institution. Of these, five (4.1%) patients underwent ECPR. Among excluded cases, 64 (53%) had nonshockable rhythms, 48 (40%) were unwitnessed arrests, 50 (42%) were over age 60 and the remaining 20 (17%) had no documented reasons for exclusion. For ECPR cases, median pre-hospital CPR duration was 26 [IQR 25-40] min. Four patients (80%) received mechanical CPR. Interval from arrest to arrival on scene was 5 [IQR 4-6] min and interval from radio call to activation of ECPR was 13 [IQR 7-21] min. Interval from EMS dispatch to departure from scene was 20 [IQR 19-21] min. Time from EMS dispatch to initiation of ECPR was 63 [IQR 59-69] min.

CONCLUSIONS

ECPR is an infrequent occurrence in EMS practice. Most apparently eligible patients did not get ECPR, highlighting the need for ongoing programmatic development, provider education, and qualitative work exploring barriers to implementation.

Sequential Pattern Mining of Longitudinal Adverse Events After Left Ventricular Assist Device Implant

Left ventricular assist devices (LVADs) are an increasingly common therapy for patients with advanced heart failure. However, implantation of the LVAD increases the risk of stroke, infection, bleeding, and other serious adverse events (AEs). Most post-LVAD AEs studies have focused on individual AEs in isolation, neglecting the possible interrelation, or causality between AEs. This study is the first to conduct an exploratory analysis to discover common sequential chains of AEs following LVAD implantation that are correlated with important clinical outcomes. This analysis was derived from 58,575 recorded AEs for 13,192 patients in International Registry for Mechanical Circulatory Support (INTERMACS) who received a continuous-flow LVAD between 2006 and 2015. The pattern mining procedure involved three main steps: (1) creating a bank of AE sequences by converting the AEs for each patient into a single, chronologically sequenced record, (2) grouping patients with similar AE sequences using hierarchical clustering, and (3) extracting temporal chains of AEs for each group of patients using Markov modeling. The mined results indicate the existence of seven groups of sequential chains of AEs, characterized by common types of AEs that occurred in a unique order. The groups were identified as: GRP1: Recurrent bleeding, GRP2: Trajectory of device malfunction & explant, GRP3: Infection, GRP4: Trajectories to transplant, GRP5: Cardiac arrhythmia, GRP6: Trajectory of neurological dysfunction & death, and GRP7: Trajectory of respiratory failure, renal dysfunction & death. These patterns of sequential post-LVAD AEs disclose potential interdependence between AEs and may aid prediction, and prevention, of subsequent AEs in future studies.

The impact of centre volume on outcomes of orthotopic heart transplant in older recipients

OBJECTIVES

The aim of this study was to evaluate the impact of overall and older-recipient-specific centre volumes on outcomes of orthotopic heart transplant (OHT) in older recipients.

METHODS

Patients aged ≥60 years undergoing OHT were identified in the United Network for Organ Sharing (UNOS) registry. The primary outcome was 1-year post-OHT mortality. Secondary outcomes included the incidence and impact on 1-year survival of postoperative complications including infection, renal failure requiring dialysis and stroke. Patients were divided into equal size tertiles based on overall and older-recipient-specific OHT centre volumes.

RESULTS

A total of 5373 older recipients were identified. Mean overall and older-recipient-specific volumes were 27.5 ± 19.5 and 9.4 ± 7.3 OHT/year, respectively. Although overall and older-recipient-specific low-volume centres were at higher risk of mortality in separate multivariable analysis, only older-recipient-specific volume contributed significantly to post-OHT mortality in the combined multivariable analysis (P < 0.05). In the receiver operating characteristic analysis, an older-recipient-specific volume of 8 OHTs/year was identified as the most discriminative volume threshold for mortality (area under the receiver operating characteristic curve = 0.68). Although low older-recipient-specific volume centres did not have significantly higher incidences of postoperative complications, they had significantly worse 1-year survival rates compared to higher volume centres in patients with postoperative infection or dialysis (each P < 0.01).

CONCLUSIONS

This large-cohort analysis demonstrates that older-recipient-specific centre volume contributes to post-OHT outcomes in the older recipients more significantly than overall volume. This may be a consequence of higher older-recipient-specific volume centres to better manage specific complications in this patient population.

Maturation of arteriovenous fistulas in patients with ventricular assist devices

OBJECTIVE

Postoperative renal dysfunction necessitating hemodialysis after implantation of ventricular assist devices presents a challenge with respect to establishment of hemodialysis access. Lack of pulsatile flow has led to concerns that arteriovenous fistulas will not mature. This study aims to evaluate arteriovenous fistula as a method of hemodialysis.

METHODS

Consecutive patients who underwent implantation of a ventricular assist device between 1988 and 2016 with a subsequent need for hemodialysis were identified. Retrospective data were collected for patients requiring hemodialysis through an arteriovenous fistula or arteriovenous graft. Access flow rates and duration of patency are reported.

RESULTS

Sixty-four patients were identified (10 required long-term hemodialysis, 5 via arteriovenous fistula, 1 via arteriovenous graft). All six patients receiving long-term hemodialysis access were on continuous-flow ventricular assist devices. Brachiocephalic arteriovenous fistulas were performed in all arteriovenous fistula patients, and the average preoperative vein diameter was 4.1 ± 0.9 mm. On 30-day follow-up, the average flow rate was 1262 ± 643 mL/min (880-2220). In arteriovenous fistula patients, one died at 30 days, one arteriovenous fistula required ligation for steal syndrome at 5 months, and one was abandoned after 10.7 months for low flow. Of remaining fistulas, one was converted to an arteriovenous graft at 1.7 years for malfunction (with 5.3 month patency), and one remains open at 4.0 years.

CONCLUSION

Arteriovenous fistulas should be considered in selected patients with ventricular assist devices as a means of long-term hemodialysis access to avoid use of catheters. Maturation and usage of primary arteriovenous fistulas is possible despite lack of pulsatile flow.

Preimplant Phosphodiesterase-5 Inhibitor Use Is Associated With Higher Rates of Severe Early Right Heart Failure After Left Ventricular Assist Device Implantation

Background Early right heart failure (RHF) occurs commonly in left ventricular assist device (LVAD) recipients, and increased right ventricular (RV) afterload may contribute. Selective pulmonary vasodilators, like phosphodiesterase-5 inhibitors (PDE5i), are used off-label to reduce RV afterload before LVAD implantation, but the association between preoperative PDE5i use and early RHF after LVAD is unknown. Methods and Results We analyzed adult patients from the INTERMACS registry (Interagency Registry for Mechanically Assisted Circulatory Support) who received a continuous flow LVAD after 2012. Patients on PDE5i were propensity-matched 1:1 to controls. The primary outcome was the incidence of severe early RHF, defined as the composite of death from RHF within 30 days, need for RV assist device support within 30 days, or use of inotropes beyond 14 days. Of 11 544 continuous flow LVAD recipients, 1199 (10.4%) received preoperative PDE5i. Compared to controls, patients on PDE5i had higher pulmonary artery systolic pressure (53.4 mm Hg versus 49.5 mm Hg) and pulmonary vascular resistance (2.6 WU versus 2.3 WU; P<0.001 for both). Before propensity matching, the incidence of severe early RHF was higher among patients on PDE5i than in controls (29.4% versus 23.1%; unadjusted odds ratio (OR), 1.32; 95% CI, 1.17-1.50). This association persisted after propensity matching (PDE5i, 28.9% versus control 23.7%; OR, 1.31; 95% CI, 1.09-1.57), driven by a higher incidence of prolonged inotropic support. Similar results were observed across a wide range of subgroups stratified by markers of pulmonary vascular disease and RV dysfunction. Conclusions Patients treated with preoperative PDE5i had markers of increased RV afterload and HF severity compared to unmatched controls. Even after propensity matching, patients receiving preimplant PDE5i therapy had higher rates of post-LVAD RHF.

A case report of extramedullary haematopoiesis within left ventricle myocardium and apical thrombus in acute heart failure: diagnosis, treatment, and long-term outcome

Background 

Extramedullary haematopoiesis (EMH) within myocardium is a rare phenomenon, and its occurrence in left ventricle myocardium or apical thrombus of a young female has never been reported.

Case summary 

A 23-year-old active female with progressive worsening of dyspnoea. A transthoracic echocardiogram demonstrated a left ventricular ejection fraction of 10–15% and apical thrombus. Bilateral upper extremity Doppler showed deep venous thrombus in the left arm and superficial vein thrombus in both arms. She had reduced activity of antithrombin III, deficiency of protein C and S. Computed tomography of the head showed right thalamic infarct. Having failed optimal medical therapy, rapidly worsening of symptoms (New York Heart Association Class IV and clinical Class C) and cardiogenic shock, she underwent HeartWare^® left ventricular assist device (LVAD) placement as a bridge to heart transplant. Intraoperative apical thrombus was carefully extracted while maintaining adequate anticoagulation with heparin infusion. Pathology report of the excised apical myocardium and thrombus demonstrated haematopoietic cells. Twenty-six months since LVAD implantation, she remains active and Status 7 on transplant list (due to body mass index) without any further episodes of thromboembolic events.

Discussion

We report an unprecedented case of an active young female with EMH within left ventricular myocardium and apical thrombus. Although redirected differentiation and embolic haematopoietic cells seem to explain this phenomenon, the exact pathophysiology remains unknown. Despite having pre-existing apical thrombus and acute deep vein thrombus, the key towards success was meticulous extraction of apical thrombus while preserving inherent trabecular architecture and adequate anticoagulation.

Center Variation in Medicare Spending for Durable Left Ventricular Assist Device Implant Hospitalizations

Importance

Hospitalizations for durable left ventricular assist device (LVAD) implants are expensive and increasingly common. Insights into center-level variation in Medicare spending for these hospitalizations are needed to inform value improvement efforts.

Objective

To examine center-level variation in Medicare spending for durable LVAD implant hospitalizations and its association with clinical outcomes.

Design, Setting, and Participants

Retrospective cohort study of linked Medicare administrative claims and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) clinical data comprising 106 centers in the United States providing durable LVAD implant. Centers were grouped into quartiles based on the mean price-standardized Medicare spending of their patients. The study included Medicare beneficiaries receiving primary durable LVAD implant between January 2008 and December 2014. Data were analyzed between November 2017 and October 2018.

Main Outcomes and Measures

Price-standardized Medicare payments and clinical outcomes. Overall and component (facility diagnosis-related group payments, outlier payments, physician services) payments and clinical outcomes (postimplant length of stay and adverse events) were compared across payment quartiles.

Results

The study sample included 4442 hospitalized patients, with mean (SD) age of 63.0 (10.8) years, 18.7% female, 27.2% nonwhite, and 6.1% Hispanic ethnicity. Among 4442 hospitalizations, the mean (SD) price-standardized Medicare payment was $176 825 ($60 286) and ranged from $122 953 to $271 472 across 106 centers. The difference in price-standardized payments between lowest and highest spending quartiles was $55 446 ($152 714 vs $208 160; 36%; P < .001), with outlier payments making up most of the difference ($42 742; 77%), followed by DRG ($6929; 13%) and physician services ($5774; 10%). After risk standardization, there was a modest decline in the difference in payments between quartiles ($53 221; 35%), with outlier payments accounting for a larger proportion of the difference (84%). After adjusting for patient characteristics, higher price-standardized payment quartiles were associated with longer postimplant length of stay but were not associated with any adverse events.

Conclusions and Relevance

Medicare payments for durable LVAD implant hospitalizations vary widely across centers; this was not well explained by prices or case mix. While associated with longer postimplant length of stay, increased spending was not associated with adverse events. As the supply and demand for durable LVAD therapy continues to rise, identifying opportunities to reduce variation in spending from both explained and unexplained sources will ensure high-value use.

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.

Eighth annual INTERMACS report: Special focus on framing the impact of adverse events

BACKGROUND

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database now includes >20,000 patients from >180 hospitals.

METHODS

The eighth annual report of INTERMACS updates the first decade of patient enrollment.

RESULTS

In the current era, >95% of implants are continuous flow devices. Overall survival continues to remain >80% at 1 year and 70% at 2 years. Review of major adverse events shows minimal advantage for patients with ambulatory heart failure pre-implant. Stroke, major infection, and continued inotrope requirement during the first 3 months have a major effect on subsequent survival.

CONCLUSIONS

Greater application of durable devices to patients with ambulatory heart failure will mandate more effective neutralization or prevention of major adverse events.

A roadmap for evaluating the use and value of durable ventricular assist device therapy

Heart failure is a disease characterized by profound human suffering with limitations in survival despite treatment with guideline-directed medical therapies. Patients with heart failure frequently progress to advanced stages and often require cardiac transplantation or implantation of left ventricular assist devices (LVADs) to extend survival and improve quality of life. As the number of suitable heart donors, number of experienced medical centers and patient comorbidities place restrictions on the feasibility of cardiac transplantation, implantation of LVADs has emerged as a more frequently applied treatment as either a bridge to transplantation or as permanent therapy. Considerable data have documented improvements in survival, functional status and quality of life offered by LVADs, however, few studies have focused on identifying: (1) determinants of LVAD use across medical centers, (2) the relationship between the determinants of LVAD use and value (defined as quality divided by cost), and (3) how determinants of LVAD use are influenced or impacted by vulnerable populations. We propose a conceptual model that integrates the main determinants of LVAD utilization, which include technology, insurance coverage, market-, provider- and patient-level factors. We propose this paradigm as a necessary prerequisite for understanding LVAD usage and value. This conceptual framework provides a broader view for future studies, which are needed to inform emerging healthcare policies that influence dissemination of this expensive but life-prolonging medical therapy.

Chemokine receptor patterns and right heart failure in mechanical circulatory support

BACKGROUND

Right ventricular failure (RVF) complicates 9% to 44% of left ventricular assist device (LVAD) implants post-operatively. Current prediction scores perform only modestly in validation studies, and do not include immune markers. Chemokines are inflammatory signaling molecules with a fundamental role in cardiac physiology and stress adaptation. In this study we investigated chemokine receptor regulation in LVAD recipients who develop RVF.

METHODS

Expression of chemokine receptor (CCR) genes 3 to 8 were examined in the peripheral blood of 111 LVAD patients, collected 24 hours before implant. RNA was isolated using a PAXgene protocol. Gene expression was assessed using a targeted microarray (RT2 Profiler PCR Array; Qiagen). Results were expressed as polymerase chain reaction (PCR) cycles to threshold and normalized to the average of 3 control genes, glyceraldehyde phosphate dehydrogenase (GAPDH), hypoxanthine phosphoribosyltransferase 1 (HPRT1) and β₂-microglobulin (B2M). Secondary outcomes studied were 1-year mortality and long-term RV failure (RVF-LT).

RESULTS

CCR3, CCR4, CCR6, CCR7 and CCR8 were downregulated in LVAD recipients with RVF. Within this cohort of patients, CCR4, CCR7 and CCR8 were further downregulated in those who required RV mechanical support. In addition, under-expression of CCR3 to CCR8 was independently associated with an increased risk of mortality at 1 year, even after adjusting for RVF. CCR expression did not predict RVF-LT in our patient cohort.

CONCLUSIONS

Pre-LVAD CCR downregulation is associated with RVF and increased mortality after implant. Inflammatory signatures may play a major role in prognostication in this patient population.

Avoidant Coping with Health Problems is Related to Poorer Quality of Life among Lung Transplant Candidates

Context

Lung transplant candidates face numerous health-related stressors. Although previous work has described the range of coping strategies candidates may use, whether those strategies are related to quality of life in physical functioning, emotional, and social domains has rarely been examined.

Methods

Adult lung transplant candidates (N=128) participated in semistructured interviews that included questions regarding global and domain-specific quality of life and a multidimensional assessment of coping with health-related problems. Demographic characteristics, health status, and other psychosocial variables were also assessed, and their effects were examined and controlled in multivariate analyses of the coping–quality-of-life relationship.

Results

Respondents were most likely to use active, acceptance, and support-seeking strategies to cope with health problems. Self-blame or avoidance were rarely used. Although used least often, avoidant coping was the most strongly and consistently related to quality of life. With demographic and psychosocial variables controlled, higher avoidant coping remained associated with significantly poorer global quality of life, bodily pain, difficulty with daily work or activities as a function of emotional problems, and depressive symptomatology. Avoidant coping accentuated the association of poor health status and lower quality of life. Among respondents with lower health status, using more avoidant coping was associated with greater difficulty functioning in daily activities as a result of emotional problems. Those with higher health status had less difficulty functioning in daily activities as a result of emotional problems.

Conclusions

Transplant team members are encouraged to be aware of and help patients refrain from using avoidant coping strategies.

Psychosocial Assessments and Outcomes in Organ Transplantation

A qualitative review was conducted to define the term psychosocial as applied to transplant patients and to summarize evidence regarding the role and impact of psychosocial assessments and outcomes across the transplant process. English-language case series and empirical studies from January 1970 through April 1990 that were abstracted in Medline and Psychological Abstracts or listed in publications' bibliographies were used as data sources. A qualitative analysis was performed to determine the depth of the case reports and whether the empirical reports obtained statistically reliable, clinically significant findings. The authors conclude that psychosocial assessments differ in content and application to candidate selection depending on the transplant program. Psychosocial status before transplant does not consistently affect medical outcomes after transplant. Psychosocial status generally improves with transplant, although difficulties are prevalent in psychological adjustment and in compliance with medical regimens. Psychiatric history can predict psychological outcomes after transplant but does not consistently predict compliance. Social supports and coping strategies strengthen psychosocial outcomes. Posttransplant psychosocial outcomes may predict physical morbidity and mortality.

The HVAD Left Ventricular Assist Device: Risk Factors for Neurological Events and Risk Mitigation Strategies

OBJECTIVES

The purpose of this study was to determine the risk factors for ischemic in hemorrhage cerebrovascular events in patients supported by the HeartWare ventricular assist device (HVAD).

BACKGROUND

Patients supported with left ventricular assist devices are at risk for both ischemic and hemorrhagic cerebrovascular events.

METHODS

Patients undergoing implantation with a HVAD as part of the bridge-to-transplant trial and subsequent continued access protocol were included. Neurological events (ischemic cerebrovascular accidents [ICVAs] and hemorrhagic cerebrovascular accidents [HCVAs]) were assessed, and the risk factors for these events were evaluated in a multivariable model.

RESULTS

A total of 382 patients were included: 140 bridge-to-transplant patients from the ADVANCE (Evaluation of the HeartWare Left Ventricular Assist Device for the Treatment of Advanced Heart Failure) clinical trial and 242 patients from the continued access protocol. Patients had a mean age of 53.2 years; 71.2% were male, and 68.1% were white. Thirty-eight percent had ischemic heart disease, and the mean duration of support was 422.7 days. The overall prevalence of ICVA was 6.8% (26 of 382); for HCVA, it was 8.4% (32 of 382). Pump design modifications and a protocol-driven change in the antiplatelet therapy reduced the prevalence of ICVA from 6.3% (17 of 272) to 2.7% (3 of 110; p = 0.21) but had a negligible effect on the prevalence of HVCA (8.8% [24 of 272] vs. 6.4% [7 of 110]; p = 0.69). Multivariable predictors of ICVA were aspirin ≤81 mg and atrial fibrillation; predictors of HCVA were mean arterial pressure >90 mm Hg, aspirin ≤81 mg, and an international normalized ratio >3.0. Eight of the 30 participating sites had established improved blood pressure management (IBPM) protocols. Although the prevalence of ICVA for those with and without IBPM protocols was similar (5.3% [6 of 114] vs. 5.2% [14 of 268]; p = 0.99), those with IBPM protocols had a significantly lower prevalence of HCVA (1.8% [2 of 114] vs. 10.8% [29 of 268]; p = 0.0078).

CONCLUSIONS

Anticoagulation, antiplatelet therapy, and blood pressure management affected the prevalence of cerebrovascular events after implantation of the HVAD. Attention to these clinical parameters can have a substantial impact on the occurrence of serious neurological events. (Evaluation of the HeartWare Left Ventricular Assist Device for the Treatment of Advanced Heart Failure [ADVANCE]; NCT00751972).

A Bayesian Model to Predict Right Ventricular Failure Following Left Ventricular Assist Device Therapy

OBJECTIVES

This study investigates the use of a Bayesian statistical model to address the limited predictive capacity of existing risk scores derived from multivariate analyses. This is based on the hypothesis that it is necessary to consider the interrelationships and conditional probabilities among independent variables to achieve sufficient statistical accuracy.

BACKGROUND

Right ventricular failure (RVF) continues to be a major adverse event following left ventricular assist device (LVAD) implantation.

METHODS

Data used for this study were derived from 10,909 adult patients from the Inter-Agency Registry for Mechanically Assisted Circulatory Support (INTERMACS) who had a primary LVAD implanted between December 2006 and March 2014. An initial set of 176 pre-implantation variables were considered. RVF post-implant was categorized as acute (<48 h), early (48 h to 14 daysays), and late (>14 days) in onset. For each of these endpoints, a separate tree-augmented naïve Bayes model was constructed using the most predictive variables employing an open source Bayesian inference engine.

RESULTS

The acute RVF model consisted of 33 variables including systolic pulmonary artery pressure (PAP), white blood cell count, left ventricular ejection fraction, cardiac index, sodium levels, and lymphocyte percentage. The early RVF model consisted of 34 variables, including systolic PAP, pre-albumin, lactate dehydrogenase level, INTERMACS profile, right ventricular ejection fraction, pro-B-type natriuretic peptide, age, heart rate, tricuspid regurgitation, and body mass index. The late RVF model included 33 variables and was predicted mostly by peripheral vascular resistance, model for end-stage liver disease score, albumin level, lymphocyte percentage, and mean and diastolic PAP. The accuracy of all Bayesian models was between 91% and 97%, with an area under the receiver operator characteristics curve between 0.83 and 0.90, sensitivity of 90%, and specificity between 98% and 99%, significantly outperforming previously published risk scores.

CONCLUSIONS

A Bayesian prognostic model of RVF based on the large, multicenter INTERMACS registry provided highly accurate predictions of acute, early, and late RVF on the basis of pre-operative variables. These models may facilitate clinical decision making while screening candidates for LVAD therapy.

Major advantages and critical challenge for the proposed United States heart allocation system

The proposed new United States allocation system incorporates extensive research into an elegant plan designed to reduce wait list mortality while preserving post-transplant outcomes. All architects are to be congratulated. However, the future cannot be reliably modeled from the past as listing practices will evolve in response to new criteria. The new system should provide a major advance if and only if it is combined with a commitment to limit the number of listed patients overall and within each high priority status to the number that could reasonably undergo timely transplantation.

Adverse events in children implanted with ventricular assist devices in the United States: Data from the Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS)

BACKGROUND

Ventricular assist devices (VADs) have been used in children on an increasing basis in recent years. One-year survival rates are now >80% in multiple reports. In this report we describe adverse events experienced by children with durable ventricular assist devices, using a national-level registry (PediMACS, a component of INTERMACS) METHODS: PediMACS is a national registry that contains clinical data on patients who are <19 years of age at the time of VAD implantation. Data collection concludes at the time of VAD explantation. All FDA-approved devices are included. PediMACS was launched on September 1, 2012, and this report includes all data from launch until August 2014. Adverse events were coded with a uniform, pre-specified set of definitions.

RESULTS

This report comprises data from 200 patients with a median age of 11 years (range 11 days to 18 years), and total follow-up of 783 patient-months. The diagnoses were cardiomyopathy (n = 146, 73%), myocarditis (n = 17, 9%), congenital heart disease (n = 35, 18%) and other (n = 2, 1%). Pulsatile-flow devices were used in 91 patients (45%) and continuous-flow devices in 109 patients (55%). Actuarial survival was 81% at 6 months. There were 418 adverse events reported. The most frequent events were device malfunction (n = 79), infection (n = 78), neurologic dysfunction (n = 52) and bleeding (n = 68). Together, these accounted for 277 events, 66% of the total. Although 38% of patients had no reported adverse event and 16% of patients had ≥5 adverse events. Adverse events occurred at all time-points after implantation, but were most likely to occur in the first 30 days. For continuous-flow devices, there were broad similarities in adverse event rates between this cohort and historic rates from the INTERMACS population.

CONCLUSIONS

In this study cohort, the overall rate of early adverse events (within 90 days of implantation) was 86.3 events per 100 patient-months, and of late adverse events it was 20.4 events per 100 patient-months. The most common adverse events in recipients of pulsatile VADs were device malfunction, neurologic dysfunction, bleeding and infection. For continuous-flow VADs, the most common adverse events were infection, bleeding, cardiac arrhythmia, neurologic dysfunction and respiratory failure. Compared with an adult INTERMACS cohort, the overall rate and distribution of adverse events appears similar.

Your Results, Explained: Clarity Provided by Row Percentages Versus Column Percentages

The overwhelming majority of clinical research papers begin their Results section with a series of tables summarizing the distribution of significant demographics, clinical characteristics, and potential outcome variables within their study cohort. However, the presentation of these tables often leaves the reader confused or wanting different information than what is presented. One particularly vexing decision in the presentation of categoric variables is choosing to present the "row percentage" in preference to the "column percentage." This report provides a guide for clinical scientists, some of whom may not have access to statistical support, to summarize their descriptive results in the manner that provides the most clarity for the reader.