Outcomes of left ventricular assist device implantation as destination therapy in the post-REMATCH era: implications for patient selection. Circulation. 2007;116:497-505. [PMID: 17638928 DOI: 10.1161/circheartfailure.108.796128]

In search of similarity in adverse events journeys of patients with left ventricular assist devices

OBJECTIVE

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Event data set contains an expansive collection of longitudinal evidence of the course of adverse events (AEs) of >15,000 patients who have received a left ventricular assist device (LVAD). Buried in the huge Event data set is knowledge that can provide a deeper understanding of the patterns of the "AE journey" of patients with LVAD. Thus, the goal of this study was to examine the Event data set from a comprehensive perspective to identify unique relationships and patterns of AEs, alert potential challenges, and suggest future research directions.

METHODS

A sequential pattern mining algorithm called SPADE (ie, Sequential PAttern Discovery using Equivalence classes) was applied to 86,912 recorded AEs of 15,820 patients with a continuous-flow LVAD between 2008 and 2016, extracted from the publicly accessible INTERMACS registry. The patterns of AE journey were investigated by posing 5 descriptive research questions about most common types of AE, concomitant AEs, AE sequences, AE subsequences, and interesting relations between AEs.

RESULTS

The analysis revealed several characteristics of patterns of the AE journey of patients who received an LVAD that accounts for the types and temporal ordering of successive AEs, combinations of AEs, and their timing after surgery.

CONCLUSIONS

The high diversity and sparsity of the types and timing of AE occurrences make the AE journeys of patients dissimilar from each other, impeding the discovery of highly-patterned AE journeys among the patients. This study suggests 2 salient directions for future studies to tackle this issue using cluster analysis to cluster patients into more similar groups and translate these results into a practical clinical tool to forecast the next AE based on the history of previous AEs.

Sex-Associated Differences in the Clinical Outcomes of Left Ventricular Assist Device Recipients: Insights From Interagency Registry for Mechanically Assisted Circulatory Support

BACKGROUND

Sex-associated differences in clinical outcomes among left ventricular assist device recipients in the United States have been recognized. However, an investigation of the social and clinical determinants of sex-associated differences is lacking.

METHODS

Left ventricular assist device receiving patients enrolled in Interagency Registry for Mechanically Assisted Circulatory Support between 2005 and 2017 were included. The primary outcome was all-cause mortality. Secondary outcomes included heart transplantation and postimplantation adverse event rates. The cohort was stratified by the social subgroup of race and ethnicity (non-Hispanic White, non-Hispanic Black, non-Hispanic Asian, and Hispanic), and clinical subgroups of device strategy (destination therapy, bridge to transplant, and bridge to candidacy), and implantation center volume (low [≤20 implants/y], medium [21-30 implants/y], and high [>30 implants/y]). A multivariable-adjusted Cox proportional hazard model was used to assess the risk of death and heart transplantation with prespecified interaction testing. Poisson regression was used to estimate adverse events by sex across the various subgroups.

RESULTS

Among 18 525 patients, there were 3968 (21.4%) females. Compared with their male counterparts, Hispanic (adjusted hazard ratio [HRadj], 1.75 [1.23-2.47]) females had the highest risk of death followed by non-Hispanic White females (HRadj, 1.15 [1.07-1.25]; Pinteraction=0.02). Hispanic (HRadj, 0.60 [0.40-0.89]) females had the lowest cumulative incidence of heart transplantation followed by non-Hispanic Black females (HRadj, 0.76 [0.67-0.86]), and non-Hispanic White females (HRadj, 0.88 [0.80-0.96]) compared with their male counterparts (Pinteraction<0.001). Compared with their male counterparts, females on the bridge to candidacy strategy (HRadj, 1.32 [1.18-1.48]) had the highest risk of death (Pinteraction=0.01). The risk of death (Pinteraction=0.44) and cumulative incidence of heart transplantation (Pinteraction=0.40) did not vary by sex in the center volume subgroup. A higher incidence rate of adverse events after left ventricular assist device implantation was also seen in females compared with the males, overall, and across all subgroups.

CONCLUSIONS

Among left ventricular assist device recipients, the risk of death, the cumulative incidence of heart transplantation, and adverse events differ by sex across the social and clinical subgroups.

Left Ventricular Assist Devices: A Primer For the General Cardiologist

Durable implantable left ventricular assist devices (LVADs) have been shown to improve survival and quality of life for patients with stage D heart failure. Even though LVADs remain underused overall, the number of patients with heart failure supported with LVADs is steadily increasing. Therefore, general cardiologists will increasingly encounter these patients. In this review, we provide an overview of the field of durable LVADs. We discuss which patients should be referred for consideration of advanced heart failure therapies. We summarize the basic principles of LVAD care, including medical and surgical considerations. We also discuss the common complications associated with LVAD therapy, including bleeding, infections, thrombotic issues, and neurologic events. Our goal is to provide a primer for the general cardiologist in the recognition of patients who could benefit from LVADs and in the principles of managing patients with LVAD. Our hope is to "demystify" LVADs for the general cardiologist.

In a large-volume multidisciplinary setting individual surgeon volume does not impact LVAD outcomes

Background

In complex operations surgeon volume may impact outcomes. We sought to understand if individual surgeon volume affects left ventricular assist device (LVAD) outcomes.

Methods

We reviewed primary LVAD implants at an experienced ventricular assist devices (VAD)/transplant center between 2013 and 2019. Cases were dichotomized into a high‐volume group (surgeons averaging 11 or more LVAD cases per year), and a low‐volume group (10 or less per year). Propensity score matching was performed. Survival to discharge, 1‐year survival, and incidence of major adverse events were compared between the low‐ and high‐volume groups. Predictors of survival were identified with multivariate analysis.

Results

There were 315 patients who met inclusion criteria‐45 in the low‐volume group, 270 in the high‐volume group. There was no difference in survival to hospital discharge between the low (91.9%) and high (83.3%) volume matched groups (p = .22). Survival at 1‐year was also similar (85.4% vs. 80.6%, p = .55). There was no difference in the incidence of major adverse events between the groups. Predictors of mortality in the first year included: age (hazards ratio [HR]: 1.061, p < .001), prior sternotomy (HR: 1.991, p = .01), increasing international normalized ratio (HR: 4.748, p < .001), increasing AST (HR: 1.001, p < .001), increasing bilirubin (HR: 1.081, p = .01), and preoperative mechanical ventilation (HR: 2.662, p = .005). Individual surgeon volume was not an independent predictor of discharge or 1‐year survival.

Conclusion

There was no difference in survival or adverse events between high and low volume surgeons suggesting that, in an experienced multidisciplinary setting, low‐volume VAD surgeons can achieve similar outcomes to their high‐volume colleagues.

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.

5-year results of a newly implemented mechanical circulatory support program for terminal heart failure patients in a Swiss non-cardiac transplant university hospital

Background

In Switzerland, long-term circulatory support programs have been limited to heart transplant centers. In 2014, to improve the management of patients with end-stage heart failure not eligible for transplantation, we implemented a left ventricular assist device (LVAD) program for destination therapy at the University Hospital of Basel.

Methods

We described the program set-up with practical aspects. Patients aged 65 and above with therapy refractory end-stage heart failure without major contraindication for LVAD implantation were included. Younger patients with bridge-to-candidacy profile were also considered. Using the Kaplan-Meier estimate, we retrospectively analyzed the overall survival and freedom from major adverse events after LVAD implantation. We compared our results to internationally reported data.

Results

Between October 2014 and September 2019, 16 patients received an LVAD in our center. The mean age at implantation was 67.1 years. The mean EuroSCORE II was 24.4% and the median INTERMACS level was 4. Thirteen patients received an LVAD as destination therapy and three patients as bridge-to-candidacy. The overall survival was 87.5 and 70% at 1 and 2 years, respectively. Freedom from stroke was 81.3% at 1 and 2 years. Freedom from device infection was 67.7 and 58.7% at 1 and 2 years, respectively. Freedom from gastrointestinal bleeding was 75 and 56.3% at 1 and 2 years, respectively. Freedom from readmission was 50 and 31.3% and at 6 months and 1 year, respectively.

Conclusions

The Basel experience demonstrated the possible implementation of an LVAD program for destination therapy or bridge-to-candidacy in a non-transplant comprehensive heart-failure center with midterm survival results and freedom from major adverse events comparable to international registries. Patient selection remains crucial.

Trial registration

This study was registered on the ClinicalTrials.gov database (NCT04263012).

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.

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.

Reviewing the use of ventricular assist devices in the elderly: where do we stand today?

INTRODUCTION

Implantation of left ventricular assist devices (LVADS) in older patients appears to be an attractive option in the wake of donor shortage and increasing incidence and prevalence of end stage heart failure. Since the inception of the artificial heart program half a century ago tremendous progress in research and development has led to utilization of more sophisticated devices. VADs have therefore emerged as a successful therapy for extending life with meaningful quality. Areas covered: This review will address the use of LVADS as a bridge to transplantation, destination therapy and comparison of LVAD therapy with alternate list heart transplantation in the elderly population. Expert commentary: Age >70 years is an important aspect when assessing LVAD risk, but other characteristics appear to be better predictors of LVAD survival. Elevated pre-operative creatinine, bilirubin and ischemic etiology predispose to a higher risk of mortality. Creatinine has been shown to be a very powerful predictor in post LVAD survival. Based on the existing literature, the authors suggest an algorithm which could be useful when evaluating patients for LVAD implantation.

More than 20 years' experience of left ventricular assist device implantation at a non-transplant Centre

OBJECTIVES

Over recent decades implantable left ventricular assist devices (LVAD) have increased the possibility of improved survival in patients with advanced heart failure who also benefit from a better quality of life. The aim of this retrospective survey was to review the clinical results of LVAD implantation at a low-volume non-transplant centre (Linköping, Sweden) between 1993 and 2016. Our aim was also to assess the mortality and morbidity rates associated with implantation of three LVAD versions at our centre, and to compare our results with those from transplant centres.

DESIGN

A retrospective cohort study was performed examining the medical records of patients who had a HeartMate^® (HMI, HMII, HMIII) LVAD implanted as a bridge to heart transplantation (BTT) or as destination therapy (DT) at the University Hospital, Linköping.

RESULTS

Our main finding was a survival to heart transplantation rate of 82% among our BTT LVAD patients. The most common adverse event among our patients was infection. A higher frequency of temporary dialysis was seen in the HMII group compared to the HMI group, and the frequency of right ventricular failure was higher in our HMII material.

CONCLUSIONS

Our data suggests that patients requiring long-term LVAD support can safely have their device implanted and cared for at a non-transplant centre.

Influence of Transplant Center Procedural Volume on Survival Outcomes of Heart Transplantation for Children Bridged with Mechanical Circulatory Support

Transplant center expertise improves survival after heart transplant (HTx) but it is unknown whether center expertise ameliorates risk associated with mechanical circulatory support (MCS) bridge to transplantation. This study investigated whether center HTx volume reduced survival disparities among pediatric HTx patients bridged with extracorporeal membrane oxygenation (ECMO), left ventricular assist device (LVAD), or no MCS. Patients ≤18 years of age receiving first-time HTx between 2005 and 2015 were identified in the United Network of Organ Sharing registry. Center volume was the total number of HTx during the study period, classified into tertiles. The primary outcome was 1 year post-transplant survival, and MCS type was interacted with center volume in Cox proportional hazards regression. The study cohort included 4131 patients, of whom 719 were supported with LVAD and 230 with ECMO. In small centers (≤133 HTx over study period), patients bridged with ECMO had increased post-transplant mortality hazard compared to patients bridged with LVAD (HR 0.29, 95% CI 0.12, 0.71; p = 0.006) and patients with no MCS (HR 0.33, 95% CI 0.19, 0.57; p < 0.001). Interactions of MCS type with medium or large center volume were not statistically significant, and the same differences in survival by MCS type were observed in medium- or large-volume centers (136-208 or ≥214 HTx over the study period). Post-HTx survival disadvantage of pediatric patients bridged with ECMO persisted regardless of transplant program volume. The role of institutional ECMO expertise outside the transplant setting for improving outcomes of ECMO bridge to HTx should be explored.

Left ventricular assist device patient selection: do risk scores help?

Mechanical circulatory support (MCS) and left ventricular assist device (LVAD) implantation is becoming increasingly utilized in the advanced heart failure (HF) population. Until further developments are made in this continually evolving field, the need for appropriate patient selection is fueled by our knowledge that the less sick do better. Due to the evolution of MCS technology, and the importance of patient selection to outcomes, risk scores and classification schemes have been developed to provide a structure for medical decision making. As clinical experience grows, technology improves, and further favorable clinical characteristics are identified, it is incumbent upon the HF community to continually hone these instruments. The magnitude of such tools cannot be understated when it comes to aiding in the informed consent and shared-decision making process for patients, families, and the healthcare team. Many risk models that have attempted to address which groups of patients will be successful focus on short term mortality and not long term survival or quality of life. The benefits and pitfalls of these models and their potential implications for patient selection and MCS therapy will be reviewed here.

Short and long term outcomes of 200 patients supported by continuous-flow left ventricular assist devices

AIM: To study the institutional experience over 8 years with 200 continuous-flow (CF) - left ventricular assist devices (LVAD).

METHODS: We evaluated our institution’s LVAD database and analyzed all patients who received a CF LVAD as a bridge to transplant (BTT) or destination therapy from March 2006 until June 2014. We identified 200 patients, of which 179 were implanted with a HeartMate II device (Thoratec Corp., Pleasanton, CA) and 21 received a Heartware HVAD (HeartWare Inc., Framingham, MA).

RESULTS: The mean age of our LVAD recipients was 59.3 years (range 17-81), 76% (152/200) were males, and 49% were implanted for the indication of BTT. The survival rate for our LVAD patients at 30 d, 6 mo, 12 mo, 2 years, 3 years, and 4 years was 94%, 86%, 78%, 71%, 62% and 45% respectively. The mean duration of LVAD support was 581 d (range 2-2595 d). Gastrointestinal bleeding (was the most common adverse event (43/200, 21%), followed by right ventricular failure (38/200, 19%), stroke (31/200, 15%), re exploration for bleeding (31/200, 15%), ventilator dependent respiratory failure (19/200, 9%) and pneumonia (15/200, 7%). Our driveline infection rate was 7%. Pump thrombosis occurred in 6% of patients. Device exchanged was needed in 6% of patients. On multivariate analysis, preoperative liver dysfunction, ventilator dependent respiratory failure, tracheostomy and right ventricular failure requiring right ventricular assist device support were significant predictors of post LVAD survival.

CONCLUSION: Short and long term survival for patients on LVAD support are excellent, although outcomes still remain inferior compared to heart transplantation. The incidence of driveline infections, pump thrombosis and pump exchange have declined significantly in recent years.

Left Ventricular Assist Devices: The Adolescence of a Disruptive Technology

Clinical outcomes for patients with advanced heart failure receiving left ventricular assist devices are driven by appropriate patient selection, refined surgical technique, and coordinated medical care. Perhaps even more important is innovative pump design. The introduction and widespread adoption of continuous-flow ventricular assist devices has led to a paradigm shift within the field of mechanical circulatory support, making the promise of lifetime device therapy closer to reality. The disruption caused by this new technology, on the one hand, produced meaningful improvements in patient survival and quality of life, but also introduced new clinical challenges, such as bleeding, pump thrombosis, and acquired valvular heart disease. Further evolution within this field will require financial investment to sustain innovation leading to a fully implantable, durable, and cost-effective pump for a larger segment of patients with advanced heart failure.

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

BACKGROUND

We examined whether characteristics, implant strategy, and outcomes in patients who receive continuous-flow left ventricular assist devices (CF-LVAD) differ across geographic regions in the United States.

METHODS

A total of 7,404 CF-LVAD patients enrolled in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) from 134 participating institutions were analyzed from 4 distinct regions: Northeast, 2,605 (35%); Midwest, 2,210 (30%); West, 973 (13%); and South, 1,616 (22%).

RESULTS

At baseline, patients in the Northeast and South were more likely to have INTERMACS risk profiles 1 and 2. A bridge-to-transplant (BTT) strategy was more common in the Northeast (31.7%; West, 18.5%; South, 26.9%; Midwest, 25.5%; p < 0.0001). In contrast, destination therapy (DT) was more likely in the South (40.6%; Northeast, 32.3%; Midwest, 27.3%; West, 27.3%; p < 0.0001). Although all regions showed a high 1-year survival rate, some regional differences in long-term mortality were observed. Notably, survival beyond 1 year after LVAD implant was significantly lower in the South. However, when stratified by device strategy, no significant differences in survival for BTT or DT patients were found among the regions. Finally, with the exception of right ventricular failure, which was more common in the South, no other significant differences in causes of death were observed among the regions.

CONCLUSIONS

Regional differences in clinical profile and LVAD strategy exist in the United States. Despite an overall high survival rate at 1 year, differences in mortality among the regions were noted. The lower survival rate in the South may be attributed to patient characteristics and higher use of LVAD as DT.

End-of-life care in patients with heart failure

Stage D heart failure (HF) is associated with poor prognosis, yet little consensus exists on the care of patients with HF approaching the end of life. Treatment options for end-stage HF range from continuation of guideline-directed medical therapy to device interventions and cardiac transplantation. However, patients approaching the end of life may elect to forego therapies or procedures perceived as burdensome, or to deactivate devices that were implanted earlier in the disease course. Although discussing end-of-life issues such as advance directives, palliative care, or hospice can be difficult, such conversations are critical to understanding patient and family expectations and to developing mutually agreed-on goals of care. Because patients with HF are at risk for rapid clinical deterioration or sudden cardiac death, end-of-life issues should be discussed early in the course of management. As patients progress to advanced HF, the need for such discussions increases, especially among patients who have declined, failed, or been deemed to be ineligible for advanced HF therapies. Communication to define goals of care for the individual patient and then to design therapy concordant with these goals is fundamental to patient-centered care. The objectives of this white paper are to highlight key end-of-life considerations in patients with HF, to provide direction for clinicians on strategies for addressing end-of-life issues and providing optimal patient care, and to draw attention to the need for more research focusing on end-of-life care for the HF population.

Institutional volume of heart transplantation with left ventricular assist device explantation influences graft survival

BACKGROUND

There are increasing numbers of patients undergoing orthotopic heart transplantation (OHT) with left ventricular assist device (LVAD) explantation (LVAD explant-OHT). We hypothesized that LVAD explant-OHT is a more challenging surgical procedure compared to OHT without LVAD explantation and that institutional LVAD explant-OHT procedural volume would be associated with post-transplant graft survival. We sought to assess the impact of institutional volume of LVAD explant-OHT on post-transplant graft survival.

METHODS

This is a retrospective analysis of the Scientific Registry of Transplant Recipients for adult OHTs with long-term LVAD explantation. LVAD explant-OHT volume was characterized on the basis of the center's year-specific total OHT volume (OHTvol) and year-specific LVAD explant-OHT volume quartile (LVADvolQ). The effect of LVADvolQ on graft survival (death or re-transplantation) was analyzed.

RESULTS

From 2004 to 2011, 2,681 patients underwent OHT with LVAD explantation (740 with HeartMate XVE, 1,877 with HeartMate II and 64 with HeartWare devices). LVAD explant-OHT at centers falling in the lowest LVADvolQ was associated with reduced post-transplant graft survival (p = 0.022). After adjusting for annualized OHTvol (HR = 0.998, 95% CI 0.993 to 1.003, p = 0.515 and pulsatile XVE (HR = 0.842, 95% CI 0.688 to 1.032, p = 0.098), multivariate analysis confirmed a significantly (approximately 37%) increased risk of post-transplant graft failure among explant-OHT procedures occurring at centers in the lowest volume quartile (HR = 1.371, 95% CI 1.030 to 1.825, p = 0.030).

CONCLUSION

Graft survival is decreased when performed at centers falling in the lowest quartile of LVAD explant-OHT for a given year. This volume-survival relationship should be considered in the context of limited donor organ availability and the rapidly growing number of LVAD centers.

Trends in the use and outcomes of ventricular assist devices among medicare beneficiaries, 2006 through 2011

OBJECTIVES

This study sought to examine trends in mortality, readmission, and costs among Medicare beneficiaries receiving ventricular assist devices (VADs) and associations between hospital-level procedure volume and outcomes.

BACKGROUND

VADs are an option for patients with advanced heart failure, but temporal changes in outcomes and associations between facility-level volume and outcomes are poorly understood.

METHODS

This is a population-based, retrospective cohort study of all fee-for-service Medicare beneficiaries with heart failure who received an implantable VAD between 2006 and 2011. We used Cox proportional hazards models to examine temporal changes in mortality, readmission, and hospital-level procedure volume.

RESULTS

Among 2,507 patients who received a VAD at 103 centers during the study period, the in-hospital mortality decreased from 30% to 10% (p < 0.001), the 1-year mortality decreased from 42% to 26% (p < 0.001), and the all-cause readmission was frequent (82% and 81%; p = 0.70). After covariate adjustment, in-hospital and 1-year mortality decreased (p < 0.001 for both), but the all-cause readmission did not change (p = 0.82). Hospitals with a low procedure volume had higher risks of in-hospital mortality (risk ratio: 1.72; 95% confidence interval [CI]: 1.28 to 2.33) and 1-year mortality (risk ratio: 1.55; 95% CI: 1.24 to 1.93) than high-volume hospitals. Procedure volume was not associated with risk of readmission. The greatest cost was from the index hospitalization and remained unchanged ($204,020 in 2006 and $201,026 in 2011; p = 0.21).

CONCLUSIONS

Short- and long-term mortality after VAD implantation among Medicare beneficiaries improved, but readmission remained similar over time. A higher volume of VAD implants was associated with lower risk of mortality but not readmission. Costs to Medicare have not changed in recent years.

Survival in elderly patients supported with continuous flow left ventricular assist device as bridge to transplantation or destination therapy

BACKGROUND

Published data on mechanical circulatory support for elderly patients in continuous flow devices are sparse and suggest relatively poor survival. This study investigated whether LVADs can be implanted in selected patients over the age of 65 years with acceptable survival compared with published outcomes.

METHODS AND RESULTS

A single-center retrospective analysis was conducted in 64 consecutive patients ≥65 years of age implanted with a continuous-flow left ventricular assist device (CF-LVAD) as either bridge to transplantation or destination therapy from August 2005 to January 2012. Baseline laboratory and hemodynamic characteristics and follow-up data were obtained. Median survival was 1,090 days. Survival was 85%, 74%, 55%, and 45% at 6 months and 1, 2, and 3 years, respectively. Our cohort had a baseline mean Seattle Heart Failure Model (SHFM) score of 2.6 ± 0.9. Observed survival was significantly better than SHFM-predicted medical survival. Stratification by age subsets, renal function, SHFM, implantation intention, or etiology did not reveal significant differences in survival. The most common cause of death was sepsis and nonlethalcomplication was bleeding.

CONCLUSIONS

Our experience with patients over the age of 65 receiving CF-LVADs suggests that this group demonstrates excellent survival. Further research is needed to discern the specific criteria for risk stratification for LVAD support in the elderly.

Continuous flow left ventricular assist device implant significantly improves pulmonary hypertension, right ventricular contractility, and tricuspid valve competence

BACKGROUND

Continuous flow left ventricular assist devices (CF LVAD) are being implanted with increasing frequency for end-stage heart failure. At the time of LVAD implant, a large proportion of patients have pulmonary hypertension, right ventricular (RV) dysfunction, and tricuspid regurgitation (TR). RV dysfunction and TR can exacerbate renal dysfunction, hepatic dysfunction, coagulopathy, edema, and even prohibit isolated LVAD implant. Repairing TR mandates increased cardiopulmonary bypass time and bicaval cannulation, which should be reserved for the time of orthotopic heart transplantation. We hypothesized that CF LVAD implant would improve pulmonary artery pressures, enhance RV function, and minimize TR, obviating need for surgical tricuspid repair.

METHODS

One hundred fourteen continuous flow LVADs implanted from 2005 through 2011 at a single center, with medical management of functional TR, were retrospectively analyzed. Pulmonary artery pressures were measured immediately prior to and following LVAD implant. RV function and TR were graded according to standard echocardiographic criteria, prior to, immediately following, and long-term following LVAD.

RESULTS

There was a significant improvement in post-VAD mean pulmonary arterial pressures (26.6 ± 4.9 vs. 30.2 ± 7.4 mmHg, p = 0.008) with equivalent loading pressures (CVP = 12.0 ± 4.0 vs. 12.1 ± 5.1 p = NS). RV function significantly improved, as noted by right ventricular stroke work index (7.04 ± 2.60 vs. 6.05 ± 2.54, p = 0.02). There was an immediate improvement in TR grade and RV function following LVAD implant, which was sustained long term.

CONCLUSION

Continuous flow LVAD implant improves pulmonary hypertension, RV function, and tricuspid regurgitation. TR may be managed nonoperatively during CF LVAD implant.

Ethical dilemmas surrounding the use of ventricular assist devices in supporting patients with end-stage organ dysfunction

Successful practice of cardiovascular medicine requires familiarity with the complex ethical issues that accompany therapeutic innovation and diffusion. Even as technologies transition from experimental to standard care, challenges remain. Mechanical circulatory support devices, for instance, are increasingly conceptualized as conventional therapies. Despite this, or perhaps because of it, the ethical issues surrounding the use of these devices in patients with end-stage organ dysfunction are becoming increasingly apparent. In this paper, we provide an introduction to ethical considerations related to the use of ventricular assist devices (VADs) in end-stage organ failure, focusing on three stages or decision points: initiation, continued use, and deactivation. Our goal is not to exhaustively resolve these dilemmas but to illustrate how ethical considerations relate to decision making.

Predicting survival in patients receiving continuous flow left ventricular assist devices: the HeartMate II risk score

OBJECTIVES

The aim of this study was to derive and validate a model to predict survival in candidates for HeartMate II (HMII) (Thoratec, Pleasanton, California) left ventricular assist device (LVAD) support.

BACKGROUND

LVAD mortality risk prediction is important for candidate selection and communicating expectations to patients and clinicians. With the evolution of LVAD support, prior risk prediction models have become less valid.

METHODS

Patients enrolled into the HMII bridge to transplantation and destination therapy trials (N = 1,122) were randomly divided into derivation (DC) (n = 583) and validation cohorts (VC) (n = 539). Pre-operative candidate predictors of 90-day mortality were examined in the DC with logistic regression, from which the HMII Risk Score (HMRS) was derived. The HMRS was then applied to the VC.

RESULTS

There were 149 (13%) deaths within 90 days. In the DC, mortality (n = 80) was higher in older patients (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1 to 1.7 per 10 years), those with greater hypoalbuminemia (OR: 0.49, 95% CI: 0.31 to 0.76 per mg/dl of albumin), renal dysfunction (OR: 2.1, 95% CI: 1.4 to 3.2 per mg/dl creatinine), coagulopathy (OR: 3.1, 95% CI: 1.7 to 5.8 per international normalized ratio unit), and in those receiving LVAD support at less experienced centers (OR: 2.2, 95% CI: 1.2 to 4.4 for <15 trial patients). Mortality in the DC low, medium, and high HMRS groups was 4%, 16%, and 29%, respectively (p < 0.001). In the VC, corresponding mortality was 8%, 11%, and 25%, respectively (p < 0.001). HMRS discrimination was good (area under the receiver-operating characteristic curve: 0.71, 95% CI: 0.66 to 0.75).

CONCLUSIONS

The HMRS might be useful for mortality risk stratification in HMII candidates and may serve as an additional tool in the patient selection process.

Can long-term ventricular assist devices be safely implanted in low-volume, non-heart transplant centres?

BACKGROUND

Mechanical circulatory support (MCS) using long-term ventricular assist devices (VADs) is an established therapy in select patients with advanced heart failure. Studies have suggested that outcomes after VAD implantation may be dependent on institutional procedural volume, and outcome data from non-transplant centres are lacking. This study reviews the outcomes of patients who received a long-term VAD at our centre to determine if these devices can be safely implanted at tertiary care, low-volume, non-transplant centres.

METHODS

We conducted a single-centre retrospective cohort study, examining the clinical outcomes of consecutive patients who received a long-term VAD over a 42-month period.

RESULTS

During the study period 73 patients required MCS, of whom 16 received a long-term VAD. This select group had a mean Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile of 1.6 (0.9) and before implantation 94% required at least 1 inotropic medication, 69% had suffered a cardiac arrest, 63% required an intra-aortic balloon pump, 69% required mechanical ventilation, and 44% required short-term MCS. The primary outcome of survival to transplant or ongoing MCS at 1 year was achieved in 75% of patients. Operating room, intensive care unit, and hospital survival were 100%, 88%, and 81%, respectively.

CONCLUSIONS

Long-term VADs can be implanted at low-volume, nontransplant centres with survival rates comparable with contemporary clinical trials. Availability of a specialty trained multidisciplinary team with expertise in short-term and long-term MCS options facilitates appropriate patient selection and might be more important than institutional volume in determining outcomes after implantation.

Hospital costs fell as numbers of LVADs were increasing: experiences from Oslo University Hospital

Background

The current study was undertaken to examine total hospital costs per patient of a consecutive implantation series of two 3^rd generation Left Ventricle Assist Devices (LVAD). Further we analyzed if increased clinical experience would reduce total hospital costs and the gap between costs and the diagnosis related grouped (DRG)-reimbursement.

Method

Cost data of 20 LVAD implantations (VentrAssist™) from 2005-2009 (period 1) were analyzed together with costs from nine patients using another LVAD (HeartWare™) from 2009-June 2011 (period 2). For each patient, total costs were calculated for three phases - the pre-LVAD implantation phase, the LVAD implantation phase and the post LVAD implant phase. Patient specific costs were obtained prospectively from patient records and included personnel resources, medication, blood products, blood chemistry and microbiology, imaging and procedure costs including operating room costs. Overhead costs were registered retrospectively and allocated to the specific patient by predefined allocation keys. Finally, patient specific costs and overhead costs were aggregated into total hospital costs for each patient. All costs were calculated in 2011-prices. We used regression analyses to analyze cost variations over time and between the different devices.

Results

The average total hospital cost per patient for the pre-LVAD, LVAD and post-LVAD for period 1 was $ 585, 513 (range 132, 640- 1 247, 299), and the corresponding DRG- reimbursement (2009) was $ 143, 192 . The mean LOS was 54 days (range 12- 127). For period 2 the total hospital cost per patient was $ 413, 185 (range 314, 540- 622, 664) and the corresponding DRG- reimbursement (2010) was $ 136, 963. The mean LOS was 49 days (range 31- 93).

The estimates from the regression analysis showed that the total hospital costs, excluding device costs, per patient were falling as the number of treated patients increased. The estimate from the trend variable was -14, 096 US$ (CI -3, 842 to -24, 349, p < 0.01).

Conclusion

There were significant reductions in total hospital costs per patient as the numbers of patients were increasing. This can possibly be explained by a learning effect including better logistics, selection and management of patients.

In vitro testing of a novel blood pump designed for temporary extracorporeal support

Extracorporeal blood pumps are used as temporary ventricular assist devices or for extracorporeal membrane oxygenation. The ideal pump would be intrinsically self-regulating, carry no risk of cavitation or excessive inlet suction, be afterload insensitive, and valveless thus reducing thrombogenicity. Currently used technology, including roller, centrifugal, and pneumatic pulsatile pumps, does not meet these requirements. We studied a nonocclusive peristaltic pump (M-Pump) in two mock circulatory loops and compared the performance to a frequently used centrifugal pump and a modified prototype of the M-Pump (the BioVAD). The simple resistance loop consisted of the investigated pump, a fixed height reservoir at 150 mm Hg, and a variable inflow reservoir. The pulsatile circulation used a mock patient simulator with adjustable resistance elements connected to a pneumatic pulsatile pump. The M-Pump intrinsically regulated flow with changing preload, was afterload insensitive, and did not cavitate, unlike the centrifugal pump. The BioVAD also demonstrated these features and could augment output with the use of vacuum assistance. A nonocclusive peristaltic pump may be superior for short-term extracorporeal circulatory assist by mitigating risks of excessive inlet suction, afterload sensitivity, and thrombosis.

New era for therapeutic strategy for heart failure: destination therapy by left ventricular assist device

Until 2010, Japan had been using the Toyobo (Nipro, Osaka, Japan) extracorporeal left ventricular assist device (VAD) developed 30 years ago as a 2-3 year bridge to transplantation (BTT). In contrast, western nations started to use implantable VADs in the 1980s that allow in-home care as destination therapy (DT) as well as BTT. Designated in 2007 as "medical devices in high demand," the 5 major implantable mechanical hearts are smoothly undergoing clinical testing. The HeartMate XVE (Thoratec Corp., Pleasanton, CA, USA) gained approval from the Ministry of Health in November of 2009, the DuraHeart (TerumoHeart, Ann Arbor, MI, USA) and EVAHEART (Sun Medical, Nagano, Japan) in December 2010, and obtained formal insurance reimbursement in April 2011. The Jarvik 2000 (Jarvik Heart Inc., New York, NY, USA) and HeartMate II (Thoratec) VADs are pending approval. On the other hand, the organ transplantation law allowing explantation of donor organs from brain-dead patients finally passed in July 2009 and was realized in July 2010. This law paved the way to pediatric heart transplants as well as a dramatic increase in overall organ transplantation cases. Because many juvenile patients awaiting donor organs need a VAD as a long-term bridge, development and clinical introduction of pediatric VADs capable of implantation is an exigency. Although expectations for transplants are high, the donor numbers are low. Therefore, the demand for implantable VADs capable of long-term home treatment is extremely high in Japan.

Bridging cardiogenic shock patients with short-term ventricular support at a community hospital to long-term ventricular support at a tertiary hospital

BACKGROUND

Patients in cardiogenic shock require immediate circulatory support. Outcomes of patients who underwent short-term ventricular assist device (STVAD) implantation in a community hospital (CH) as a bridge to a long-term VAD (LTVAD) were compared with those who received both implants at the same tertiary hospital (TH).

METHODS

Data were retrospectively reviewed for patients with a STVAD who were bridged to a LTVAD in a TH from 1997 to 2010. We studied outcomes and survival censored for cardiac transplantation.

RESULTS

Thirty-seven patients (73% male) were identified. Mean age was 52 ± 16 years, 30% were diabetic, and 65% had intra-aortic balloon pump support. Reasons for STVAD implantation were an acute myocardial infarction, 38%; post-cardiotomy, 38%, decompensated chronic heart failure, 19%; and others, 5%. A STVAD was implanted in a CH in 20 patients (54%), and they had fewer cardiovascular risk factors than those whose STVAD was implanted at the TH. All patients at the CH were at Interagency Registry for Mechanically Assisted Circulatory Support 1 compared with 71% at the TH (p = 0.014). Patients from the CH tended to die sooner after LTVAD implant, although long-term survival was similar. At the 1-year follow-up, 65% from the CH were alive or had received a transplant vs 60% from the TH.

CONCLUSION

Patients with cardiogenic shock in whom a STVAD was implanted in a CH and then were bridged to a LTVAD in a TH had similar long-term survival as those bridged to LTVAD at the TH.

Effective ventricular unloading by left ventricular assist device varies with stage of heart failure: cardiac simulator study

Although the use of left ventricular assist devices (LVADs) as a bridge-to-recovery (BTR) has shown promise, clinical success has been limited due to the lack of understanding the timing of implantation, acute/chronic device setting, and explantation. This study investigated the effective ventricular unloading at different heart conditions by using a mock circulatory system (MCS) to provide a tool for pump parameter adjustments. We tested the hypothesis that effective unloading by LVAD at a given speed varies with the stage of heart failure. By using a MCS, systematic depression of cardiac performance was obtained. Five different stages of heart failure from control were achieved by adjusting the pneumatic systolic/diastolic pressure, filling pressure, and systemic resistance. The Heart Mate II® (Thoratec Corp., Pleasanton, CA) was used for volumetric and pressure unloading at different heart conditions over a given LVAD speed. The effective unloading at a given LVAD speed was greater in more depressed heart condition. The rate of unloading over LVAD speed was also greater in more depressed heart condition. In conclusion, to get continuous and optimal cardiac recovery, timely increase in LVAD speed over a period of support is needed while avoiding the akinesis of aortic valve.

Clinical strategies and outcomes in advanced heart failure patients older than 70 years of age receiving the HeartMate II left ventricular assist device: a community hospital experience

OBJECTIVES

The primary objective of this study was to determine outcomes in left ventricular assist device (LVAD) patients older than age 70 years.

BACKGROUND

Food and Drug Administration approval of the HeartMate II (Thoratec Corporation, Pleasanton, California) LVAD for destination therapy has provided an attractive option for older patients with advanced heart failure.

METHODS

Fifty-five patients received the HeartMate II LVAD between October 5, 2005, and January 1, 2010, as part of either the bridge to transplantation or destination therapy trials at a community hospital. Patients were divided into 2 age groups: ≥ 70 years of age (n = 30) and < 70 years of age (n = 25). Outcome measures including survival, length of hospital stay, adverse events, and quality of life were compared between the 2 groups.

RESULTS

Pre-operatively, all patients were in New York Heart Association functional class IV refractory to maximal medical therapy. Kaplan-Meier survival for patients ≥ 70 years of age (97% at 1 month, 75% at 1 year, and 70% at 2 years) was not statistically different from patients <7 0 years of age (96% 1 month, 72% at 1 year, and 65% at 2 years, p = 0.806). Average length of hospital stay for the ≥ 70-year age group was 24 ± 15 days, similar to that of the < 70-year age group (23 ± 14 days, p = 0.805). There were no differences in the incidence of adverse events between the 2 groups. Quality of life and functional status improved significantly in both groups.

CONCLUSIONS

The LVAD patients ≥ 70 years of age have good functional recovery, survival, and quality of life at 2 years. Advanced age should not be used as an independent contraindication when selecting a patient for LVAD therapy at experienced centers.

Positron emission tomography for the evaluation and treatment of cardiomyopathy

Congestive heart failure accounts for tremendous morbidity and mortality worldwide. There are numerous causes of cardiomyopathy, the most common of which is coronary artery disease. Positron emission tomography (PET) has an established and expanding role in the evaluation of patients with cardiomyopathy. The specific application of PET to hypertrophic cardiomyopathy, cardiac sarcoidosis, and diabetic cardiomyopathy has been studied extensively and promises to be a useful tool for managing these patients. Furthermore, evaluating the efficacy of standard treatments for congestive heart failure is important as health care costs continue to rise. Recently, there have been significant developments in the field of cardiovascular stem cell research. Familiarity with the mechanisms by which stem cells benefit patients with cardiovascular disease is the key to understanding these advances. Molecular imaging techniques including PET/CT imaging play an important role in monitoring stem cell therapy in both animals and humans. These noninvasive imaging techniques will be highlighted in this paper.

The next decade in mechanical assist: advances that will help the patient and the doctor

PURPOSE OF REVIEW

Significant technological advances have occurred in mechanical assist devices over the past decade. With improving hemodynamics and durability, ventricular assist devices (VADs) are being implanted with increasing frequency. Yet, several VAD-specific morbidities and technological challenges, which are reviewed, continue to limit the number of devices that are currently implanted.

RECENT FINDINGS

We are beginning to understand the pathophysiology of complications specific to continuous-flow VADs, including bleeding and aortic insufficiency. Improved outcomes and durability with currently available continuous-flow VADs are evident, as compared with first-generation devices. A focus on enhancing quality of life with a VAD will be critical to widespread application of mechanical circulatory support to the heart failure patient population.

SUMMARY

Advances in technology and surgical technique are continuing to minimize morbidity and mortality associated with mechanical assist devices. Continued technological advancements will allow increased utilization of mechanical circulatory support over the next decade.

Lifestyle adjustments of adults with long-term implantable left ventricular assist devices: a phenomenologic inquiry

OBJECTIVE

To explore and describe the lifestyle adjustments made by adult recipients of a long-term implantable left ventricular assist device (LVAD).

METHODS

A phenomenologic inquiry was used to uncover the lifestyle adjustments of 7 men and 2 women, ages 31 to 70 years, who had an LVAD for more than 3 months after hospital discharge.

RESULTS

An overarching theme, "adjustment takes time," represents the lifestyle adjustments of the study participants. Early adjustment was highlighted by participants' concerns with physical, psychologic, and environmental aspects, whereas late adjustment was highlighted by behaviors associated with acceptance of the LVAD as an integral component of their bodies and lives.

CONCLUSION

This study provides insight into the patient's perspective regarding the challenges faced in living with an LVAD. The findings inform health care providers in the acute and critical care settings in assisting patients to positively adjust with the lifestyle imposed by an LVAD.