Effect of Body Mass Index on Outcomes in Left Ventricular Assist Device Recipients

Sleeve gastrectomy as a bridge to cardiac recovery - A retrospective comparative cohort study

Background

Obesity in patients with heart failure with reduced ejection fraction (HFrEF) increases morbidity and may preclude them from accessing advanced heart failure therapies. Bariatric surgery, specifically sleeve gastrectomy (SG), may improve eligibility for cardiac transplant; however, its impact on heart failure outcomes is not well defined.

Methods

We conducted a retrospective cohort study of patients with obesity (body mass index [BMI] ≥35 kg/m2) and (left ventricular ejection fraction [LVEF] ≤40%) who underwent SG at a tertiary heart transplant center. Outcomes were compared with controls matched for age, sex, LVEF, and BMI receiving standard care. We evaluated BMI, New York Heart Association (NYHA) functional class, medications, echocardiographic parameters, time to advanced heart failure therapies, and survival.

Results

Twenty patients (median BMI 42.8 kg/m², LVEF 25%) underwent SG compared to 40 matched patients. Both groups demonstrated reductions in BMI; however, weight loss was significantly greater in the treatment group (-9.9 [95% CI -12.2, -7.6] vs. -2.7 [-4.3, -1.1] kg/m², p < 0.05). Despite this, improvements in LVEF (+16.6% [10.2, 23.0] vs. +0.1% [-4.4, 4.7], p < 0.05) along with NYHA class (-0.8 [95% CI: -1.3, -0.3] vs. +0.4 [0.1, 0.7], p < 0.05) were only observed in those receiving SG. Overall survival was significantly higher in the treatment group [HR: 0.2 (0.07, 0.62), p < 0.01], which had no deaths compared to 35% in the comparison group.

Conclusion

In patients with HFrEF and obesity, SG is associated with significant improvements in cardiac function and survival compared to standard care, supporting its role as a safe and effective bridge to recovery or candidacy.

Determinants of Functional Capacity and Quality of Life After Implantation of a Durable Left Ventricular Assist Device

Continuous-flow left ventricular assist devices (LVAD) are increasingly used as destination therapy in patients with end-stage heart failure and, with recent improvements in pump design, adverse event rates are decreasing. Implanted patients experience improved survival, quality of life (QoL) and functional capacity (FC). However, improvement in FC and QoL after implantation is not unequivocal, and this has implications for patient selection and preimplantation discussions with patients and relatives. This article identifies preimplantation predictors of lack of improvement in FC and QoL after continuous-flow LVAD implantation and discusses potential mechanisms, allowing for the identification of potential factors that can be modified. In particular, the pathophysiology behind insufficient improvement in peak oxygen uptake is discussed. Data are included from 40 studies, resulting in analysis of >700 exercise tests. Mean peak oxygen uptake was 13.4 ml/kg/min (equivalent to 48% of predicted value; 259 days after implantation, range 31–1,017 days) and mean 6-minute walk test distance was 370 m (182 days after implantation, range 43–543 days). Finally, the interplay between improvement in FC and QoL is discussed.

Relation of Body Mass Index to Outcomes in Patients With Heart Failure Implanted With Left Ventricular Assist Devices

We aimed at characterizing the impact of low and high body mass index (BMI) on outcomes after left-ventricular assist device (LVAD) surgery and define the predictors of mortality in patients with abnormal BMI (low/high). This study was conducted in 19 centers from 2006 to 2016. Patients were divided based on their baseline BMI into 3 groups of BMI: low (BMI ≤18.5 kg/m²); normal (BMI = 18.5 to 24.99 kg/m²) and high (BMI ≥25 kg/m²) (including overweight (BMI = 25 to 29.99 kg/m²), and obesity (BMI ≥30 Kg/m²)). Among 652 patients, 29 (4.4%), 279 (42.8%) and 344 (52.8%) had a low-, normal-, and high BMI, respectively. Patients with high BMI were significantly more likely men, with more co-morbidities and more history of ventricular/supra-ventricular arrhythmias before LVAD implantation. Patients with abnormal BMI had significantly lower survival than those with normal BMI. Notably, those with low BMI experienced the worst survival whereas overweight or obese patients had similar survival. Four predictors of mortality for LVAD candidates with abnormal BMI were defined: total bilirubin ≥16 µmol/L before LVAD, hypertension, destination therapy, and cardiac surgery with LVAD. Depending on the number of predictor per patients, those with abnormal BMI may be divided in 3 groups of 1-year mortality risk, i.e., low (0 to 1 predictor: 29% and 31%), intermediate (2 to 3 predictors, 51% and 52%, respectively), and high (4 predictors: 83%). In conclusion, LVAD recipients with abnormal BMI experience lower survival, especially underweight patients. Four predictors of mortality have been identified for LVAD population with abnormal BMI, differentiating those a low-, intermediate-, and high risks of death.

The Impact of Left Ventricular Assist Device Infections on Postcardiac Transplant Outcomes: A Systematic Review and Meta-Analysis

Left ventricular assist devices (LVADs) are associated with numerous short- and long-term complications, including infection. The impact LVAD infections have on clinical outcomes after transplantation is not well established. We sought to determine whether the presence of infection while on LVAD support negatively influences outcomes after cardiac transplantation. We searched electronic databases and bibliographies for full text studies that identified LVAD infections during support and also reported on posttransplant outcomes. A meta-analysis of posttransplant survival was conducted using a random effects model. Of 2,373 records, 13 bridge to transplant (BTT) cohort studies were selected (n = 6,631, 82% male, mean age 50.7 ± 2.7 years). A total of 6,067 records (91.5%) received transplant. There were 3,718 (56.1%) continuous-flow LVADs (CF-LVADs), 1,752 (26.4%) pulsatile LVADs, and 1,161 (17.5%) unknown type records. A total of 2,586 records (39.0%) developed LVAD infections. Patients with LVAD infections were younger (50.5 ± 1.5 vs. 51.3 ± 1.5, p = 0.02), had higher body mass indeices (BMIs) (28.4 ± 0.7 vs. 26.8 ± 0.4, p < 0.01), and longer LVAD support times (347.0 ± 157.6 days vs. 180.2 ± 106.0 days, p < 0.01). Meta-analysis demonstrated increased posttransplant mortality in those patients who had an LVAD infection (hazard ratio [HR] 1.30, 95% CI: 1.16-1.46, p < 0.001). Subgroup meta-analyses by continuous-flow and pulsatile device type demonstrated significant increased risk of death for both types of devices (HR 1.47, 95% CI: 1.22-1.76, p < 0.001 and 1.71, 95% CI: 1.19-2.45, p = 0.004, respectively). Patients who develop LVAD infections are younger, have higher BMIs and longer LVAD support times. Our data suggests that LVAD-related infections result in a 30% increase in postcardiac transplantation mortality. Strategies to prevent LVAD infections should be implemented to improve posttransplant outcomes in this high-risk population.

Comparative analysis of regional outcomes and adverse events after continuous-flow left ventricular assist device implantation: An IMACS analysis

INTRODUCTION

Regional outcomes after implantation of continuous-flow left ventricular assist devices (LVADs) have not been described. We examined differences in patient selection, survival, and adverse events across 3 geographic regions of the world: the Americas, Asia-Pacific, and Europe.

METHODS

Using data from The International Society for Heart and Lung Transplantation Mechanically Assisted Circulatory Support registry, all adult patients implanted with a continuous-flow LVADs were included in this International Society for Heart and Lung Transplantation Mechanically Assisted Circulatory Support analysis (n = 15,560), of whom, 9,988 (64%) received axial-flow devices and 5,572 (36%) received centrifugal-flow devices.

RESULTS

There were significant interregional differences in the rate of implantation of patients aged >70 years (Americas: 14%, Asia-Pacific: 1%, Europe: 5%; p < 0.0001), morbidly obese (Americas: 5%, Asia-Pacific: 1%, Europe: 1%; p < 0.0001), male (Americas: 79%, Asia-Pacific: 77%, Europe: 85%; p < 0.0001), and implanted as destination therapy (Americas: 48%, Asia-Pacific: 4%, Europe: 22%; p < 0.0001). The rates of centrifugal pump usage varied by region (Americas: 30%, Asia-Pacific: 34%, Eu: 74%; p < 0.0001). Survival rates varied by region and the type of pump flow, with survival at 12 and 48 months (axial flow vs centrifugal flow) being 82% vs 82% and 52% vs 53 in Americas; 92% vs 86% and 83% vs 74% in Asia-Pacific; and 80% vs 75% and 69% vs 53% in Europe, respectively (regional survival p < 0.0001).

CONCLUSION

There are marked global differences in LVAD recipient characteristics, device utilization, and post-operative care. These heterogeneities along with differences in patient management and transplantation rates may impact long-term survival. Regional differences in adverse event incidence warrant further investigation.

Impact of Change in Body Mass Index on Outcomes After Left Ventricular Assist Device Implantation in Obese Patients

Obesity could be a risk factor portending a poor prognosis after left ventricular assist device (LVAD) implantation. We sought to determine the impact of change in body mass index (BMI) on outcomes in obese patients supported by LVAD. Fifty-nine patients, who received LVAD between January 2010 and June 2015, with BMI ≥30 kg/m at the time of LVAD implantation, were retrospectively analyzed. Patients were divided into two groups based upon whether BMI after 6 months of device support decreased when compared with before. Thirty-eight patients who experienced decrease in BMI (group D) were compared with 21 patients whose BMI increased (group I). Baseline characteristics were similar between the groups except for body weight and BMI, which were significantly higher in group D (BMI: 35.9 ± 4.0 kg/m vs. 33.4 ± 3.5 kg/m; p = 0.018). During mean follow-up of 560 ± 178 days, group I had significantly higher incidence of infection [events per patient-years (eppy): nondevice related: 0.18 vs. 0.35, p = 0.01; device related: 0.1 vs. 0.32, p < 0.01; sepsis: 0.1 vs. 0.32, p < 0.01], heart failure (eppy: 0.1 vs. 0.25, p < 0.01), and renal failure (eppy: 0.03 vs. 0.14, p < 0.01). Survival at 2 years was significantly lower in group I (84.8% vs. 57.1%, p = 0.025). Increase in BMI in obese patients on LVAD is associated with worse survival with a higher incidence of infection, heart failure, and renal failure. Weight control may be a modifiable factor to improve prognosis.

Impact of body mass index on adverse events after implantation of left ventricular assist devices: An IMACS registry analysis

BACKGROUND

Limited data exist describing impact of body mass index (BMI) on post‒left ventricular assist device (post-LVAD) outcomes. We sought to define the relationship between body mass index (BMI) and adverse events (AEs) after LVAD implantation by examining the ISHLT Mechanically Assisted Circulatory Support (IMACS) registry.

METHODS

Patients implanted with a contemporary continuous flow (CF)-LVAD were stratified into 4 groups using pre-operative BMI: underweight (UW; BMI ≤18.5 kg/m²); non-obese (NO; BMI >18.5 to <30 kg/m²); obese (OB; BMI ≥30 to <40 kg/m²); and morbidly obese (MO; BMI ≥40 kg/m²). Freedom from AEs was evaluated using the Kaplan-Meier method and risk factors for development of first AE were identified using multiphase parametric hazard modeling. AEs included infection, thromboembolic events, bleeding, device malfunction, and neurologic dysfunction.

RESULTS

Between 2013 and 2015, a total of 9,408 patients underwent implantation of a CF-LVAD, which consisted of 368 (4%) UW, 5,719 (61%) NO, 2,770 (29%) OB, and 444 (5%) MO patients. Survival among the 4 BMI cohorts was similar at 2years (70.8% to 75.8%, p = 0.24). MO patients were less likely to be free from a non‒VAD-related infection (p < 0.0001) or device-related infection (p = 0.0014) at 2years (50.3%, 70.7%) when compared with OB (58.3%, 78.7%), NO (65.2%, 81.4%), and UW (68.9%, 77.4%) patients. UW (81.5%) and NO (81.3%) patients were more likely to be free from device malfunction at 2years when compared with OB (78.3%) and MO (72.6%) (p = 0.0006). Thromboembolic events were rare and more common in the UW cohort (p = 0.026).

CONCLUSIONS

Although BMI was not correlated with 2-year mortality, an increased rate of infectious and device-related AEs was noted in OB and MO LVAD patients. In a group with few options for transplant, the event morbidity in obese patients can be expected to impact morbidity with longer support durations.

Elevated Body Mass Index Is Not a Risk Factor for Adverse Outcomes Following Ventricular Assist Device Implantation

BACKGROUND

Despite ventricular assist devices (VADs) becoming more common in heart failure (HF) treatment, it is still uncertain which patients are more prone to complications. One potential risk factor is increased body mass index (BMI), which is known to increase both all-cause mortality and mortality from ischemic heart disease; however, the role of the BMI in predicting morbidity and mortality following device implantation is unclear.

METHODS

The study population for this single-institution retrospective chart review consisted of 136 patients with HF, who underwent VAD implantation between 2004 and 2015. Patients were divided into 2 groups based on their BMI: a nonobese group (18.5 < BMI < 30.0; n = 82) or an obese group (BMI >30.0; n = 54). These groups were compared at baseline and after implantation for survival, hospital readmission, and adverse events.

RESULTS

No significant difference was found in initial hospital length of stay, number or length of readmissions, or readmission diagnosis. At 1 year, rates of ongoing device support, orthotopic heart transplant (OHT), and death were not significantly different between groups ( P = .89, P = .90, and P = .70, respectively). Multivariate analysis did not identify obesity as an independent predictor of mortality ( P = .90); only biventricular assist device implantation was associated with decreased survival (hazard ratio [HR] = 5.90, P = .002).

CONCLUSION

Obesity in itself should not preclude the use of VAD support in patients with HF, as carefully selected obese patients were shown to have similar rates of hospital readmission, 1-year outcomes, and survival following device implantation compared to nonobese patients.

Prevention and Treatment of Thrombotic and Hemorrhagic Complications in Patients Supported by Continuous-Flow Left Ventricular Assist Devices

PURPOSE OF REVIEW

The purpose of this review is to describe the current knowledge in prevention and treatment of thrombotic (pump thrombosis and ischemic stroke) and bleeding (gastrointestinal and hemorrhagic stroke) complications in patients supported by continuous-flow left ventricular assist devices (CF-LVAD).

RECENT FINDINGS

Left ventricular assist devices (LVADs) are now widely used for the management of end-stage heart failure. Unfortunately, in spite of the indisputable positive impact LVADs have on patients, the frequency and severity of complications are limitations of this therapy. Stroke, pump thrombosis, and gastrointestinal bleeding are among the most serious and frequent complications in these patients. The balance between hemorrhagic and thrombotic complications in patients supported with CF-LVAD is difficult as most patients do not necessarily fit a "bleeder" or a "clotter" profile but rather move from one side to the other of the thrombotic/bleeding spectrum. Further research is necessary to better understand the risk factors and mechanisms involved in the development of these complications.

Effect of obesity on outcomes in patients undergoing implantation of continuous-flow left ventricular assist devices

The purpose of this study was to analyze the effect of obesity on outcomes after continuous-flow left ventricular assist device (CF-LVAD) implantation. A single-center retrospective analysis was performed on 526 chronic heart failure patients who were implanted with the HeartMate II CF-LVAD (n = 403) or HeartWare HVAD (n = 123) between November 2003 and March 2016. Patients were stratified into 4 groups based on BMI: underweight (< 18.5 kg/m², n = 18, 3.4%), normal-weight (18.5-25 kg/m², n = 173, 32.9%), overweight (25-30 kg/m², n = 182, 30.2%), and obese (> 30 kg/m², n = 153, 33.5%). The underweight group was excluded because of its small sample size. Records were reviewed to determine the incidence of postoperative complications and survival. Survival at 1, 6, 12, and 24 months were similar among normal-weight (91.3, 84.4, 76.3, and 67.6%), overweight (90.4, 80.8, 76.5, and 69.6%), and obese patients (90.7, 74.7, 65.3, and 61.3%, p = 0.24). Additionally, obesity was not a significant predictor of mortality in Cox proportional hazard models (hazard ratio 0.98, 95% confidence interval 0.766-1.277, p = 0.13). These findings suggest that appropriately selected obese patients receive similar survival benefit from CF-LVADs compared to non-obese patients, and obesity should not serve as a contraindication to CF-LVAD implantation.

The inodilator levosimendan in repetitive doses in the treatment of advanced heart failure

Inotropes may be an appropriate response for some patients with advanced heart failure who remain highly symptomatic despite optimization of evidence-based therapy. These patients need to be supported waiting for a heart transplant or ventricular assist device, or may be candidates for inotropy as an intervention in its own right to maintain a patient in the best achievable circumstances. Objectives in such a situation include relieving symptoms, improving quality of life and reducing unplanned hospitalizations and the costs associated with such admissions. Levosimendan, a calcium sensitizer and potassium channel opener with inotrope and vasodilator actions, has emerged as a potentially valuable addition to the armamentarium in this context, used in repeated or intermittent cycles of therapy. Detailed proposals and guidance are offered for the identification of candidate patients with good prospects of a beneficial response to levosimendan, and for the safe and effective implementation of a course of therapy.

Higher Body Mass Index Increases Risk of HeartMate II Pump Thrombosis But Does Not Adversely Affect Long-Term Survival

BACKGROUND

Obesity has been correlated with various adverse events in patients who receive left ventricular assist devices (LVAD). In this study, we sought to further characterize the role of obesity in this patient population.

METHODS AND RESULTS

We performed a retrospective analysis of 164 patients implanted with a HeartMate II from August 2008 to December 2014. Patients were categorized into 2 BMI groups based on WHO guidelines: BMI 18.5-30 kg/m2(n=99) and BMI >30 kg/m2(n=65). Patient demographics, adverse outcome and long-term survival were compared between the 2 groups. For any outcome associated with BMI groups, we performed a Cox regression to identify confounding comorbidities. Preoperative demographics and comorbidities were similar. Patients with BMI >30 were younger (P=0.01) and had a higher incidence of type 2 diabetes (P=0.01). While rate of pump thrombosis was higher among patients with BMI >30 (P=0.02), overall survival at 2 years did not differ. The most common cause of death was hemorrhagic stroke in the obese group. On multivariable cox regression analysis, BMI was an independent risk factor of pump thrombosis.

CONCLUSIONS

Higher BMI does not reduce survival after VAD implantation but it does appear to increase the risk of pump thrombosis. Further studies to characterize the role of BMI in survival and thrombosis rates are warranted.