Patient selection for ventricular assist devices: a moving target

Hold or fold--proteins in advanced heart failure and myocardial recovery

Advanced heart failure (AHF) describes the subset of heart failure patients refractory to conventional medical therapy. For some AHF patients, the use of mechanical circulatory support (MCS) provides an intermediary "bridge" step for transplant-eligible patients or an alternative therapy for transplant-ineligible patients. Over the past 20 years, clinical observations have revealed that approximately 1% of patients with MCS undergo significant reverse remodeling to the point where the device can be explanted. Unfortunately, it is unclear why some patients experience durable, sustained myocardial remission, while others redevelop heart failure (i.e. which hearts "hold" and which hearts "fold"). In this review, we outline unmet clinical needs related to treating patients with MCS, provide an overview of protein dynamics in the reverse-remodeling process, and propose specific areas where we expect MS and proteomic analyses will have significant impact on our understanding of disease progression, molecular mechanisms of recovery, and provide new markers with prognostic value that can positively impact patient care. Complimentary perspectives are provided with the goal of making this important topic accessible and relevant to both a clinical and basic science audience, as the intersection of these disciplines is required to advance the field.

Clinical outcomes after continuous-flow left ventricular assist device: a systematic review

BACKGROUND

Conveying the complex trade-offs of continuous-flow left ventricular assist devices is challenging and made more difficult by absence of an evidence summary for the full range of possible outcomes. We aimed to summarize the current evidence on outcomes of continuous-flow left ventricular assist devices.

METHODS AND RESULTS

PubMed and Cochrane Library were searched from January 2007 to December 2013, supplemented with manual review. Three reviewers independently assessed each study for saliency on patient-centered outcomes. Data were summarized in tabular form. Overall study characteristics encouraged inclusion of all indications (destination therapy and bridge to transplant) and prevented meta-analysis. The electronic search identified 465 abstracts, of which 50 met inclusion criteria; manual review added 2 articles in press. The articles included 10 industry-funded trials and registries, 10 multicenter reports, and the remainder single-center observational experiences. Estimated actuarial survival after continuous-flow left ventricular assist devices ranged from 56% to 87% at 1 year, 43% to 84% at 2 years, and 47% at 4 years. Improvements in functional class and quality of life were reported, but missing data complicated interpretation. Adverse events were experienced by the majority of patients, but estimates for bleeding, stroke, infection, right heart failure, arrhythmias, and rehospitalizations varied greatly.

CONCLUSIONS

The totality of data for continuous-flow left ventricular assist devices show consistent improvements in survival and quality of life counterbalanced by a range of common complications. Although this summary should provide a practical resource for healthcare provider-led discussions with patients, it highlights the critical need for high-quality patient-centered data collected with standard definitions.

Clinical outcomes after continuous-flow left ventricular assist device: a systematic review

BACKGROUND

Conveying the complex trade-offs of continuous-flow left ventricular assist devices is challenging and made more difficult by absence of an evidence summary for the full range of possible outcomes. We aimed to summarize the current evidence on outcomes of continuous-flow left ventricular assist devices.

METHODS AND RESULTS

PubMed and Cochrane Library were searched from January 2007 to December 2013, supplemented with manual review. Three reviewers independently assessed each study for saliency on patient-centered outcomes. Data were summarized in tabular form. Overall study characteristics encouraged inclusion of all indications (destination therapy and bridge to transplant) and prevented meta-analysis. The electronic search identified 465 abstracts, of which 50 met inclusion criteria; manual review added 2 articles in press. The articles included 10 industry-funded trials and registries, 10 multicenter reports, and the remainder single-center observational experiences. Estimated actuarial survival after continuous-flow left ventricular assist devices ranged from 56% to 87% at 1 year, 43% to 84% at 2 years, and 47% at 4 years. Improvements in functional class and quality of life were reported, but missing data complicated interpretation. Adverse events were experienced by the majority of patients, but estimates for bleeding, stroke, infection, right heart failure, arrhythmias, and rehospitalizations varied greatly.

CONCLUSIONS

The totality of data for continuous-flow left ventricular assist devices show consistent improvements in survival and quality of life counterbalanced by a range of common complications. Although this summary should provide a practical resource for healthcare provider-led discussions with patients, it highlights the critical need for high-quality patient-centered data collected with standard definitions.

Ventricular assist devices in children

PURPOSE OF REVIEW

Ventricular assist devices (VADs) have revolutionized heart failure management in adults. Recently, VADs have similarly taken a prominent role in the management of end-stage heart failure in children. The purpose of this review is to describe the indications for VADs in children, types of devices available, current outcomes, and future directions of VAD therapy.

RECENT FINDINGS

There has been a dramatic increase in VAD utilization in children over the last decade. For small children, paracorporeal pneumatic pulsatile pumps (e.g., Berlin Heart EXCOR VAD, Berlin Heart GmbH, Berlin, Germany) are most commonly utilized for long-term support. In older children, intracorporeal continuous flow devices (e.g., HeartMate II Left Ventricular Assist System, Thoratec Corporation, Pleasanton, California, USA and HeartWare Ventricular Assist System, HeartWare Incorporated, Framingham, Massachusetts, USA) have been used and allow the possibility of destination therapy. Other devices, such as the total artificial heart, can be utilized for selected patients. Although overall outcomes of pediatric VADs are favorable, complication rates remain high. The utilization of VADs in complex circulations, such as single ventricle patients, remains infrequent and is associated with a high rate of adverse outcomes.

SUMMARY

VADs are well-established treatment for end-stage heart failure in children. Further investigation is needed to refine patient selection criteria, minimize complications, and develop additional pediatric-specific devices.

Durable mechanical circulatory support in advanced heart failure: a critical care cardiology perspective

Though cardiac transplantation for advanced heart disease patients remains definitive therapy for patients with advanced heart failure, it is challenged by inadequate donor supply, causing durable mechanical circulatory support (MCS) to slowly become a new primary standard. Selecting appropriate patients for MCS involves meeting a number of prespecifications as is required in evaluation for cardiac transplant candidacy. As technology evolves to bring forth more durable smaller devices, selection criteria for appropriate MCS recipients will likely expand to encompass a broader, less sick population. The "Holy Grail" for MCS will be a focus on clinical recovery and explantation of devices rather than the currently more narrowly defined indications of bridge to transplantation or lifetime device therapy.

Decision making for destination therapy left ventricular assist devices: "there was no choice" versus "I thought about it an awful lot"

BACKGROUND

Destination therapy left ventricular assist devices (DT LVADs) are one of the most invasive medical interventions for end-stage illness. How patients decide whether or not to proceed with device implantation is unknown. We aimed to understand the decision-making processes of patients who either accept or decline DT LVADs.

METHODS AND RESULTS

Between October 2012 and September 2013, we conducted semistructured, in-depth interviews to understand patients' decision-making experiences. Data were analyzed using a mixed inductive and deductive approach. Twenty-two eligible patients were interviewed, 15 with DT LVADs and 7 who declined. We found a strong dichotomy between decision processes with some patients (11 accepters) being automatic and others (3 accepters, 7 decliners) being reflective in their approach to decision making. The automatic group was characterized by a fear of dying and an over-riding desire to live as long as possible: "[LVAD] was the only option I had…that or push up daisies…so I automatically took this." By contrast, the reflective group went through a reasoned process of weighing risks, benefits, and burdens: "There are worse things than death." Irrespective of approach, most patients experienced the DT LVAD decision as a highly emotional process and many sought support from their families or spiritually.

CONCLUSIONS

Some patients offered a DT LVAD face the decision by reflecting on a process and reasoning through risks and benefits. For others, the desire to live supersedes such reflective processing. Acknowledging this difference is important when considering how to support patients who are faced with this complex decision.

Comparative Survival and Cost-Effectiveness of Advanced Therapies for End-Stage Heart Failure

Background—

Treatment options for end-stage heart failure include inotrope-dependent medical therapy, orthotopic heart transplantation (OHT), left ventricular assist device (LVAD) as destination therapy or bridge to transplant.

Methods and Results—

We developed a state-transition model to simulate 4 treatment options and associated morbidity and mortality. Transition probabilities, costs, and utilities were estimated from published sources. Calculated outcomes included survival, quality-adjusted life-years, and incremental cost-effectiveness. Sensitivity analyses were performed on model parameters to test robustness. Average life expectancy for OHT-eligible patients is estimated at 1.1 years, with 39% surviving to 1 year. OHT with a median wait time of 5.6 months is estimated to increase life expectancy to 8.5 years, and costs <$100 000/quality-adjusted life-year gained, relative to inotrope-dependent medical therapy. Bridge to transplant-LVAD followed by OHT further is estimated to increase life expectancy to 12.3 years, for $226 000/quality-adjusted life-year gained versus OHT. Among OHT-ineligible patients, mean life expectancy with inotrope-dependent medical therapy is estimated at 9.4 months, with 26% surviving to 1 year. Patients who instead received destination therapy-LVAD are estimated to live 4.4 years on average from extrapolation of recent constant hazard rates beyond the first year. This strategy costs $202 000/quality-adjusted life-year gained, relative to inotrope-dependent medical therapy. Patient’s age, time on wait list, and costs associated with care influence outcomes.

Conclusions—

Under most scenarios, OHT prolongs life and is cost effective in eligible patients. Bridge to transplant-LVAD is estimated to offer >3.8 additional life-years for patients waiting ≥6 months, but does not meet conventional cost-effectiveness thresholds. Destination therapy-LVAD significantly improves life expectancy in OHT-ineligible patients. However, further reductions in adverse events or improved quality of life are needed for destination therapy-LVAD to be cost effective.

Regional differences in recipient waitlist time and pre- and post-transplant mortality after the 2006 United Network for Organ Sharing policy changes in the donor heart allocation algorithm

OBJECTIVES

This study examined the impact of the United Network for Organ Sharing (UNOS) policy changes for regional differences in waitlist time and mortality before and after heart transplantation.

BACKGROUND

The 2006 UNOS thoracic organ allocation policy change was implemented to allow for greater regional sharing of organs for heart transplantation.

METHODS

We analyzed 36,789 patients who were listed for heart transplantation from January 1999 through April 2012. These patients were separated into 2 eras centered on the July 12, 2006 UNOS policy change. Pre- and post-transplantation characteristics were compared by UNOS regions.

RESULTS

Waitlist mortality decreased nationally (up to 180 days: 13.3% vs. 7.9% after the UNOS policy change, p < 0.001) and within each region. Similarly, 2-year post-transplant mortality decreased nationally (2-year mortality: 17.3% vs. 14.6%; p < 0.001) as well as regionally. Waitlist time for UNOS status 1A and 1B candidates increased nationally 17.8 days on average (p < 0.001) with variability between the regions. The greatest increases were in Region 9 (59.2-day increase, p < 0.001) and Region 4 (41.2-day increase, p < 0.001). Although the use of mechanical circulatory support increased nearly 2.3-fold nationally in Era 2, significant differences were present on a regional basis. In Regions 6, 7, and 10, nearly 40% of those transplanted required left ventricular assist device bridging, whereas only 19.6%, 22.3%, and 15.5% required a left ventricular assist device in regions 3, 4, and 5, respectively.

CONCLUSIONS

The 2006 UNOS policy change has resulted in significant regional heterogeneity with respect to waitlist time and reliance on mechanical circulatory support as a bridge to transplantation, although overall both waitlist mortality and post-transplant survival are improved.

Decompensated heart failure

Heart failure is a disease with high incidence and prevalence in the population. The costs with hospitalization for decompensated heart failure reach approximately 60% of the total cost with heart failure treatment, and mortality during hospitalization varies according to the studied population, and could achieve values of 10%. In patients with decompensated heart failure, history and physical examination are of great value for the diagnosis of the syndrome, and also can help the physician to identify the beginning of symptoms, and give information about etiology, causes and prognosis of the disease. The initial objective of decompensated heart failure treatment is the hemodynamic and symptomatic improvement preservation and/or improvement of renal function, prevention of myocardial damage, modulation of the neurohormonal and/or inflammatory activation and control of comorbidities that can cause or contribute to progression of the syndrome. According to the clinical-hemodynamic profile, it is possible to establish a rational for the treatment of decompensated heart failure, individualizing the proceedings to be held, leading to reduction in the period of hospitalization and consequently reducing overall mortality.

The ADHF/NT-proBNP risk score to predict 1-year mortality in hospitalized patients with advanced decompensated heart failure

BACKGROUND

The acute decompensated heart failure/N-terminal pro-B-type natriuretic peptide (ADHF/NT-proBNP) score is a validated risk scoring system that predicts mortality in hospitalized heart failure patients with a wide range of left ventricular ejection fractions (LVEFs). We sought to assess discrimination and calibration of the score when applied to patients with advanced decompensated heart failure (AHF).

METHODS

We studied 445 patients hospitalized for AHF, defined by the presence of severe symptoms of worsening HF at admission, severely depressed LVEF, and the need for intravenous diuretic and/or inotropic drugs. The primary outcome was cumulative (in-hospital and post-discharge) mortality and post-discharge 1-year mortality. Separate analyses were performed for patients aged ≤ 70 years. A Seattle Heart Failure Score (SHFS) was calculated for each patient discharged alive.

RESULTS

During follow-up, 144 patients (32.4%) died, and 69 (15.5%) underwent heart transplantation (HT) or ventricular assist device (VAD) implantation. After accounting for the competing events (VAD/HT), the ADHF/NT-proBNP score's C-statistic for cumulative mortality was 0.738 in the overall cohort and 0.771 in patients aged ≤ 70 years. The C-statistic for post-discharge mortality was 0.741 and 0.751, respectively. Adding prior (≤6 months) hospitalizations for HF to the score increased the C-statistic for post-discharge mortality to 0.759 in the overall cohort and to 0.774 in patients aged ≤ 70 years. Predicted and observed mortality rates by quartiles of score were highly correlated. The SHFS demonstrated adequate discrimination but underestimated the risk. The ADHF/NT-proBNP risk calculator is available at http://www.fsm.it/fsm/file/NTproBNPscore.zip.

CONCLUSIONS

Our data suggest that the ADHF/NT-proBNP score may efficiently predict mortality in patients hospitalized with AHF.

Pre-operative health status and outcomes after continuous-flow left ventricular assist device implantation

BACKGROUND

Health status predicts adverse outcomes in heart failure and cardiac surgery patients, but its prognostic value in left ventricular assist device (LVAD) placement is unknown.

METHODS

We examined the association of pre-operative health status, as measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ), with survival and hospitalization after LVAD using the KCCQ score as a continuous variable and stratified by KCCQ score quartile plus missing KCCQ in 1,125 clinical trial participants who received the HeartMate II (Thoratec Corp, Pleasanton, CA) as destination therapy (n = 635) or bridge to transplantation (n = 490).

RESULTS

The mean pre-operative KCCQ score was 29.4 ± 18.7 among survivors (n = 719), and 27.1 ± 18.3 (n = 406) in those who died. In time-to-event analysis for all available follow-up using health status as a continuous variable, the pre-operative KCCQ score did not correlate with overall mortality after LVAD implantation (p = 0.178). Small absolute differences were seen between the pre-operative KCCQ quartile and 30-day survival (Q4 95% vs. Q1 89% vs. missing 87%; p = 0.0009 for trend), 180-day survival (Q4 83% vs. Q1 76% vs missing 79%; p = 0.060 for trend), and days hospitalized at 180 days (Q4 29.8 ± 25.6 vs. Q1 34.1 ± 27.1 vs. missing 36.5 ± 29.9 days; p = 0.009 for trend).

CONCLUSION

Our findings suggest that pre-operative health status has limited association with outcomes after LVAD implantation. Although these data require further study in a diverse population, mechanical circulatory support may represent a relatively unique clinical situation, distinct from heart failure and other cardiac surgeries, in which heart failure-specific health status measures may be largely reversed.