Regional differences in use and outcomes of left ventricular assist devices: Insights from the Interagency Registry for Mechanically Assisted Circulatory Support Registry

The Long-Term Survival of LVAD Patients-A TriNetX Database Analysis

Background: Donor shortage limits the utilization of heart transplantation, making it available for only a fraction of the patients on the transplant waiting list. Therefore, continuous-flow left ventricular assist devices (CF-LVADs) have evolved as a standard of care for end-stage heart failure. It is imperative therefore to investigate long-term survival in this population. Methods: This study assesses the impact of demographics, infections, comorbidities, types of cardiomyopathies, arrhythmias, and end-organ dysfunction on the long-term survival of LVAD recipients. The TriNetX database comprises de-identified patient information across healthcare organizations. The log-rank test assessed post-implant survival effects, while Cox regression was used in the univariate analysis to obtain the Hazard Ratio (HR). All analyses were conducted using the Python programming language and the lifelines library. Results: This study identified CMV, hepatitis A exposure, atrial fibrillation, paroxysmal ventricular tachycardia, ischemic cardiomyopathy, renal dysfunction, diabetes, COPD, mitral valve disease, and essential hypertension as risk factors that impact long-term survival. Interestingly, hypokalemia seems to have a protective effect and gender does not affect survival significantly. Conclusions: This is the first report of a detailed long-term survival assessment of the LVAD population using a decoded database.

The impact of diabetes on short-, intermediate- and long-term mortality following left ventricular assist device implantation

OBJECTIVES

Type 2 diabetes mellitus (DM) is a frequent comorbidity among patients suffering from advanced heart failure necessitating a left ventricular assist device (LVAD) implant. The goal of this study was to evaluate the impact of type 2 DM on early and long-term outcomes of patients following an LVAD implant.

METHODS

We performed an observational cohort study in a large tertiary care centre in Israel. All data of patients who underwent a continuous flow LVAD implant between 2006 and 2020 were extracted from our departmental database. Patients were divided into 2 groups: group I (patients without diabetes) and group II (patients with diabetes). We compared short-term (30-day and 3-month) mortality, intermediate-term (1- and 3-year) mortality and long-term (5 year) mortality between the 2 groups.

RESULTS

The study population included 154 patients. Group I (patients without diabetes) comprised 88 patients and group II (patients with diabetes) comprised 66 patients. The mean follow-up duration was 38.2 ± 30.3 months. Short- and intermediate-term mortality (30 days, 1 year and 3 years) was higher in the group with DM compared with the group without DM but did not reach any statistically significant difference: 16.1% vs 9.8% (P = 0.312), 24.2% vs 17.3% (P = 0.399) and 30.6% vs 21.9% (P = 0.127) respectively. Long-term 5-year mortality was significantly higher in the group with DM compared to the group without: 38.7% vs 24.4% (P = 0.038). Furthermore, predictors of long-term mortality included diabetes (hazard ratio 2.09, confidence interval 1.34-2.84, P = 0.004), as demonstrated by regression analysis.

CONCLUSIONS

Patients with diabetes and those without diabetes have similar 30-day and short- and intermediate-term mortality rates. The mortality risk of diabetic patients begins to increase 3 years after an LVAD implant. Diabetes is an independent predictor of long-term, 5-year mortality after an LVAD implant.

CLINICAL TRIAL REGISTRATION

Ethical Committee of Sheba Medical Centre, Israel, on 2 December 2014, Protocol 4257.

Impact of Shared Care in Remote Areas for Patients With Left Ventricular Assist Devices

OBJECTIVES

The aim of this study was to evaluate the impact of a shared-care model on outcomes in patients with left ventricular assist devices (LVADs) living in remote locations.

BACKGROUND

Health care delivery through shared-care models has been shown to improve outcomes in patients with chronic diseases. However, the impact of shared-care models on outcomes in patients with LVAD is unknown.

METHODS

LVAD recipients in the authors' program (2007 to 2018) were classified based on the levels of care provided and training and resources used: level 1, was defined as outpatient primary care without LVAD-specific care; level 2 was level 1 services and outpatient LVAD-specific care; level 3 was level 2 services and inpatient LVAD-specific care and implantation center (IC). The Kaplan-Meier method was used to compare rates of survival, bleeding, pump thrombosis, infection, neurologic events, and readmissions among levels of care.

RESULTS

A total of 336 patients were included, with 255 patients (75.9%) cared for in shared-care facilities. Median follow-up was 810 (interquartile range: 321 to 1,096) days. In comparison to patients cared for by IC, patients at levels 2 and 3 shared-care centers had similar rates of death, bleeding, neurologic events, pump thromboses, and infections. However, the rates of death, pump thromboses, and infections were higher for level 1 patients than in IC patients.

CONCLUSIONS

Shared health care is an effective strategy to deliver care to patients with LVAD living in remote locations. However, patients in shared-care facilities unable to provide LVAD-specific care are at higher risk of unfavorable outcomes. Availability of LVAD-specific care should be strongly considered during patient selection and every effort made to ensure LVAD-specific training and resources are available at shared-care facilities.

Trends in utilization, mortality, and resource use after implantation of left ventricular assist devices in the United States

OBJECTIVES

Adoption of implantable left ventricular assist devices has dramatically improved survival and quality of life in suitable patients with end-stage heart failure. In the era of value-based healthcare delivery, assessment of clinical outcomes and resource use associated with left ventricular assist devices is warranted.

METHODS

Adult patients undergoing left ventricular assist device implantation from 2008 to 2016 were identified using the National Inpatient Sample. Hospitals were designated as low-volume, medium-volume, or high-volume institutions based on annual institutional left ventricular assist device case volume. Multivariable logistic regression was used to evaluate adjusted odds of mortality across left ventricular assist device volume tertiles.

RESULTS

Over the study period, an estimated 23,972 patients underwent left ventricular assist device implantation with an approximately 3-fold increase in the number of annual left ventricular assist device implantations performed (P for trend <.001). In-hospital mortality in patients with left ventricular assist devices decreased from 19.6% in 2008 to 8.1% in 2016 (P for trend <.001) and was higher at low-volume institutions compared with high-volume institutions (12.0% vs 9.2%, P < .001). Although the overall adjusted mortality was higher at low-volume compared with high-volume institutions (adjusted odds ratio, 1.66; 95% confidence interval, 1.28-2.15), this discrepancy was only significant for 2008 and 2009 (low-volume 2008 adjusted odds ratio, 5.5; 95% confidence interval, 1.9-15.8; low-volume 2009 adjusted odds ratio, 2.3; 95% confidence interval, 1.4-3.8).

CONCLUSIONS

Left ventricular assist device use has rapidly increased in the United States with a concomitant reduction in mortality and morbidity. With maturation of left ventricular assist device technology and increasing experience, volume-related variation in mortality and resource use has diminished. Whether the apparent uniformity in outcomes is related to patient selection or hospital quality deserves further investigation.

Association of Transplant Center With Survival Benefit Among Adults Undergoing Heart Transplant in the United States

IMPORTANCE

In the United States, the number of deceased donor hearts available for transplant is limited. As a proxy for medical urgency, the US heart allocation system ranks heart transplant candidates largely according to the supportive therapy prescribed by transplant centers.

OBJECTIVE

To determine if there is a significant association between transplant center and survival benefit in the US heart allocation system.

DESIGN, SETTING, AND PARTICIPANTS

Observational study of 29 199 adult candidates for heart transplant listed on the national transplant registry from January 2006 through December 2015 with follow-up complete through August 2018.

EXPOSURES

Transplant center.

MAIN OUTCOMES AND MEASURES

The survival benefit associated with heart transplant as defined by the difference between survival after heart transplant and waiting list survival without transplant at 5 years. Each transplant center's mean survival benefit was estimated using a mixed-effects proportional hazards model with transplant as a time-dependent covariate, adjusted for year of transplant, donor quality, ischemic time, and candidate status.

RESULTS

Of 29 199 candidates (mean age, 52 years; 26% women) on the transplant waiting list at 113 centers, 19 815 (68%) underwent heart transplant. Among heart transplant recipients, 5389 (27%) died or underwent another transplant operation during the study period. Of the 9384 candidates who did not undergo heart transplant, 5669 (60%) died (2644 while on the waiting list and 3025 after being delisted). Estimated 5-year survival was 77% (interquartile range [IQR], 74% to 80%) among transplant recipients and 33% (IQR, 17% to 51%) among those who did not undergo heart transplant, which is a survival benefit of 44% (IQR, 27% to 59%). Survival benefit ranged from 30% to 55% across centers and 31 centers (27%) had significantly higher survival benefit than the mean and 30 centers (27%) had significantly lower survival benefit than the mean. Compared with low survival benefit centers, high survival benefit centers performed heart transplant for patients with lower estimated expected waiting list survival without transplant (29% at high survival benefit centers vs 39% at low survival benefit centers; survival difference, -10% [95% CI, -12% to -8.1%]), although the adjusted 5-year survival after transplant was not significantly different between high and low survival benefit centers (77.6% vs 77.1%, respectively; survival difference, 0.5% [95% CI, -1.3% to 2.3%]). Overall, for every 10% decrease in estimated transplant candidate waiting list survival at a given center, there was an increase of 6.2% (95% CI, 5.2% to 7.3%) in the 5-year survival benefit associated with heart transplant.

CONCLUSIONS AND RELEVANCE

In this registry-based study of US heart transplant candidates, transplant center was associated with the survival benefit of transplant. Although the adjusted 5-year survival after transplant was not significantly different between high and low survival benefit centers, compared with centers with survival benefit significantly below the mean, centers with survival benefit significantly above the mean performed heart transplant for recipients who had significantly lower estimated expected 5-year waiting list survival without transplant.

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.

Retrospective Evaluation of Bayesian Risk Models of LVAD Mortality at a Single Implant Center

Use of a left ventricular assist device (LVAD) can benefit patients with end stage heart failure, but only with careful patient selection. In this study, previously derived Bayesian network models for predicting LVAD patient mortality at 1, 3, and 12 months post-implant were evaluated on retrospective data from a single implant center. The models performed well at all three time points, with a receiver operating characteristic area under the curve (ROC AUC) of 78, 76, and 75%, respectively. This evaluation of model performance verifies the utility of these models in "real life" scenarios at an individual institution.

Regional Variation in Mortality, Major Complications, and Cost After Left Ventricular Assist Device Implantation in the United States (2009 to 2014)

The objective of this analysis was to provide evidence on regional differences in outcomes, cost and disposition among patients who undergo continuous-flow LVAD implantation. Using data from the National Inpatient Sample and US Census Bureau, annual national estimates in utilization, in-hospital mortality, major complications, cost, length of stay (LOS), and disposition were estimated for years 2009 to 2014. Main outcomes and complications were identified using patient safety indicators and International Classification of Diseases-Ninth Revision, Clinical Modification codes. We analyzed a total of 3,572 (weighted = 17,552) patients with LVAD implants among the 4 Census regions of the United States. The patient population in the Southern region was younger with higher percentage of African-Americans. Overall, the comorbidity burden was higher in the Midwest. The risk-adjusted rate of in-hospital mortality did not differ significantly among the geographical regions (p = 0.8). With the exception of cardiac tamponade rates which were higher in the Northeast and West, all other post-operative complications did not differ between regions. LOS was higher in the Northeast (median 32 days) and lower in the South (median 27 days). The cost analysis suggested higher median cost in the West (median $246,292) and lowest in the Northeast region (median $192,604). Finally, higher percentages of patients were transferred to an extended care facility in the Northeast, whereas more patients were discharged to home in the Western region. We identified region disparities in LOS, cost and disposition but not in-hospital mortality and complications, among patients who underwent LVAD implantation between 2009 and 2014.

Ten thousand kilometre transfer of cardiogenic shock patients on venoarterial extracorporeal membrane oxygenation for emergency heart transplantation: Cooperation between Reunion Island and Metropolitan France

Background:

There is no heart transplantation centre on the French overseas territory of Reunion Island (distance of 10,000 km). The aim of this study was to describe the characteristics of cardiogenic shock adult patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO) who were transferred from Reunion Island to mainland France for emergency heart transplantation.

Methods:

This retrospective observational study was conducted between 2005 and 2015. The characteristics and outcome of cardiogenic shock patients on VA-ECMO were compared with those of cardiogenic shock patients not on VA-ECMO.

Results:

Thirty-three cardiogenic shock adult patients were transferred from Reunion Island to Paris for emergency heart transplantation. Among them, 19 (57.6%) needed mechanical circulatory support in the form of VA-ECMO. Median age was 51 (33–57) years and 46% of the patients had ischaemic heart disease. Patients on VA-ECMO presented higher Sequential Organ Failure Assessment score ( p = 0.03). No death occurred during the medical transfer by long flight, while severe complications occurred in 10 patients (30.3%). Incidence of thromboembolic events, severe infectious complications and major haemorrhages was higher in the group of patients on VA-ECMO than in the group of patients not on VA-ECMO ( p <0.01). Seven patients from the VA-ECMO group (36.8%) and six patients from the non-VA-ECMO group (42.9%, p=0.7) underwent heart transplantation after a median delay of 10 (4–29) days on the emergency waiting list. After heart transplantation, one-year survival rates were 85.7% for patients on VA-ECMO and 83.3% for patients not on VA-ECMO ( p=0.91).

Conclusions:

This study suggests the feasibility of very long-distance medical evacuation of cardiogenic shock patients on VA-ECMO for emergency heart transplantation, with acceptable long-term results.