Ventricular assist devices or inotropic agents in status 1A patients? Survival analysis of the United Network of Organ Sharing database

Mechanical Assist Device-Assisted Percutaneous Coronary Intervention: The Use of Impella Versus Extracorporeal Membrane Oxygenation as an Emerging Frontier in Revascularization in Cardiogenic Shock

The extracorporeal membrane oxygenation (ECMO) procedure aids in the provision of prolonged cardiopulmonary support, whereas the Impella device (Abiomed, Danvers, MA) is a ventricular assist device that maintains circulation by pumping blood into the aorta from the left ventricle. Blood is circulated in parallel with the heart by Impella. It draws blood straight into the aorta from the left ventricle, hence preserving the physiological flow. ECMO bypasses the left atrium and the left ventricle, and the end consequence is a non-physiological flow. In this article, we conducted a detailed analysis of various publications in the literature and examined various modalities pertaining to the use of ECMO and Impella for cardiogenic shocks, such as efficacy, clinical outcomes, cost-effectiveness, device-related complications, and limitations. The Impella completely unloads the left ventricle, thereby significantly reducing the effort of the heart. Comparatively, ECMO only stabilizes a patient with cardiogenic shock for a short stretch of time and does not lessen the efforts of the left ventricle ("unload" it). In the acute setting, both devices reduced left ventricular end-diastolic pressure and provided adequate hemodynamic support. By comparing patients on Impella to those receiving ECMO, it was found that patients on Impella were associated with better clinical results, quicker recovery, limited complications, and reduced healthcare costs; however, there is a lack of conclusive studies performed demonstrating the reduction in long-term mortality rates. Considering the effectiveness of given modalities and taking into account the various studies described in the literature, Impella has reported better clinical outcomes although more clinical trials are needed for establishing the effectiveness of these interventional approaches in revascularization in cardiogenic shock.

Intra-Aortic Balloon Pumping in Acute Decompensated Heart Failure With Hypoperfusion: From Pathophysiology to Clinical Practice

Trials on intra-aortic balloon pump (IABP) use in cardiogenic shock related to acute myocardial infarction have shown disappointing results. The role of IABP in cardiogenic shock treatment remains unclear, and new (potentially more potent) mechanical circulatory supports with arguably larger device profile are emerging. A reappraisal of the physiological premises of intra-aortic counterpulsation may underpin the rationale to maintain IABP as a valuable therapeutic option for patients with acute decompensated heart failure and tissue hypoperfusion. Several pathophysiological features differ between myocardial infarction- and acute decompensated heart failure-related hypoperfusion, encompassing cardiogenic shock severity, filling status, systemic vascular resistances rise, and adaptation to chronic (if preexisting) left ventricular dysfunction. IABP combines a more substantial effect on left ventricular afterload with a modest increase in cardiac output and would therefore be most suitable in clinical scenarios characterized by a disproportionate increase in afterload without profound hemodynamic compromise. The acute decompensated heart failure syndrome is characterized by exquisite afterload-sensitivity of cardiac output and may be an ideal setting for counterpulsation. Several hemodynamic variables have been shown to predict response to IABP within this scenario, potentially guiding appropriate patient selection. Finally, acute decompensated heart failure with hypoperfusion may frequently represent an end stage in the heart failure history: IABP may provide sufficient hemodynamic support and prompt end-organ function recovery in view of more definitive heart replacement therapies while preserving ambulation when used with a transaxillary approach.

Temporal trends and outcomes of patients waiting on left ventricular assist devices and inotropes for heart transplantation

We sought to evaluate the trends and outcomes of patients with left ventricular assist devices (LVADs) and inotropes at the time of listing for heart transplantation. Adults with an LVAD implanted and listed with 1A status were identified in the United Network for Organ Sharing (UNOS) registry between 2010 and 2017. Patients were grouped according to the presence or absence of inotropes at the time of listing and transplantation. A total of 2714 patients were included in the study including 664 patients on inotropes at the time of listing, 235 at the time of transplantation, and 118 on inotropes both at listing and at the time of transplantation. Patients on LVAD and inotropes at the time of listing were more frequently supported with a right ventricular assist device (RVAD) (P < .001), had higher risk of death in the waiting list (sub-hazard ratio [SHR] = 1.48, 95% CI 1.14-1.90, P = .002), and were less likely to be transplanted (SHR = 0.70, 95% CI 0.63-0.78, P < .001) compared with those not on inotropes, after adjusting for described confounders. Approximately 1 in 10 LVAD recipients listed as status 1A are on inotropic therapy at the time of heart transplantation. Patients on LVAD and inotropes have worse outcomes in terms of survival and lower rates of transplantation.

Mechanical Circulatory Support for Acute Heart Failure Complicated by Cardiogenic Shock

Acute heart failure is a potentially life-threatening condition that can lead to cardiogenic shock, which is associated with hypotension and organ failure. Although there have been many studies on the treatment for cardiogenic shock, early mortality remains high at 40–50%. No new medicines for cardiogenic shock have been developed. Recently, there has been a gradual decline in the use of the intra-aortic balloon pump mainly due to a lack of adequate hemodynamic support. Extracorporeal membrane oxygenation and the percutaneous ventricular assist device have become more widely used in recent years. A thorough understanding of the mechanisms of such mechanical support devices and their hemodynamic effects, components of the devices, implantation technique, management, criteria for indications or contraindications of use, and clinical outcomes as well as multidisciplinary decision making may improve the outcomes in patients experiencing cardiogenic shock.

Surgical Approaches in Heart Failure

Heart failure is a progressive condition that continues to increase in both incidence and prevalence despite pharmacologic treatment. The high rate of morbidity and mortality associated with advanced heart failure has led to exploration of additional treatments, which include surgical interventions to improve outcomes. Heart transplant remains the gold standard but, because of the persistent donor shortage and increasing number of patients with advanced heart failure, mechanical circulatory support is gaining acceptance and can be used as a bridge to heart transplant for those eligible or as destination therapy.

Comparison of Transplant Waitlist Outcomes for Pediatric Candidates Supported by Ventricular Assist Devices Versus Medical Therapy

OBJECTIVES

Ventricular assist devices have gained popularity in the management of refractory heart failure in children listed for heart transplantation. Our primary aim was to compare the composite endpoint of all-cause pretransplant mortality and loss of transplant eligibility in children who were treated with a ventricular assist device versus a medically managed cohort.

DESIGN

This was a retrospective cohort analysis.

SETTINGS

Data were obtained from the Scientific Registry of Transplant Recipients.

PATIENTS

The at-risk population (n = 1,380) was less than 18 years old, either on a ventricular assist device (605 cases) or an equivalent-severity, intensively medically treated group (referred to as MED, 775 cases).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The impact of ventricular assist devices was estimated via Cox proportional hazards regression (hazard ratio), dichotomizing 1-year outcomes to "poor" (22%: 193 deaths, 114 too sick) versus all others (940 successful transplants, 41 too healthy, 90 censored), while adjusting for conventional risk factors. Among children 0-12 months old, ventricular assist device was associated with a higher risk of poor outcomes (hazard ratio, 2.1; 95% CI, 1.5-3.0; p < 0.001). By contrast, ventricular assist device was associated with improved outcomes for ages 12-18 (hazard ratio, 0.3; 95% CI, 0.1-0.7; p = 0.003). For candidates 1-5 and 6-11 years old, there were no differences in outcomes between the ventricular assist device and MED groups (hazard ratio, 0.8 and 1.0, p = 0.43 and 0.9). The interaction between ventricular assist devices and age group was strongly significant (p < 0.001).

CONCLUSIONS

This is a comparative study of ventricular assist devices versus medical therapy in children. Age is a significant modulator of waitlist outcomes for children with end-stage heart failure supported by ventricular assist device, with the impact of ventricular assist devices being more beneficial in adolescents.

Ventricular assist devices as bridge to heart transplantation: impact on post-transplant infections

Background

Ventricular assist devices (VAD) are valuable options for patients with heart failure awaiting cardiac transplantation. We assessed the impact of pre-transplant VAD implantation on the incidence of post-transplant infections in a nationwide cohort of heart transplant recipients.

Methods

Heart transplant recipients included in the Swiss Transplant Cohort Study between May 2008 and December 2012 were analyzed. Cumulative incidence curves were used to calculate the incidence of bacterial or Candida infections (primary endpoint) and of other infections (secondary endpoint) after transplant. Cox regression models treating death as a competing risk were used to identify risk factors for the development of infection after transplant.

Results

Overall, 119 patients were included in the study, 35 with a VAD and 84 without VAD. Cumulative incidences of post-transplant bacterial or Candida infections were 37.7 % in VAD patients and 40.4 % in non-VAD patients. In multivariate analysis, the use of cotrimoxazole prophylaxis was the only variable associated with bacterial/Candida infections after transplant (HR 0.29 [95 % CI 0.15-0.57], p < 0.001), but presence of a VAD was not (HR 0.94, [95 % CI 0.38-2.32], p = 0.89, for continuous-flow devices, and HR 0.45 [0.15 – 1.34], p = 0.15, for other devices). Risk for post-transplant viral and all fungal infections was not increased in patients with VAD. One-year survival was 82.9 % (29/35) in the VAD group and 82.1 % (69/84) in the non-VAD group. All 6 patients in the VAD group that died after transplant had a history of pre-transplant VAD infection.

Conclusion

In this nationwide cohort of heart transplant recipients, the presence of VAD at the time of transplant had no influence on the development of post-transplant infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1658-0) contains supplementary material, which is available to authorized users.

Current Status of Left Ventricular Assist Device Therapy

Congestive heart failure (HF) remains a serious burden in the Western World. Despite advances in pharmacotherapy and resynchronization, many patients have progression to end-stage HF. These patients may be candidates for heart transplant or left ventricular assist device (LVAD) therapy. Heart transplants are limited by organ shortages and in some cases by patient comorbidities; therefore, LVAD therapy is emerging as a strategy of bridge to transplant or as a destination therapy in patients ineligible for transplant. Patients initially ineligible for a transplant may, in certain cases, become eligible for transplant after physiologic improvement with LVAD therapy, and a small number of patients with an LVAD may have sufficient recovery of myocardial function to allow device explantation. This clinically oriented review will describe (1) the most frequently used pump types and aspects of the continuous-flow physiology and (2) the clinical indications for and the shift toward the use of LVADs in less sick patients with HF. Additionally, we review complications of LVAD therapy and project future directions in this field. We referred to the Interagency Registry for Mechanically Assisted Circulatory Support, landmark trials, and results from recently published studies as major sources in obtaining recent outcomes, and we searched for related published literature via PubMed. This review focuses primarily on clinical practice for primary care physicians and non-HF cardiologists in the United States.

Influence of durable mechanical circulatory support and allosensitization on mortality after heart transplantation

BACKGROUND

Allosensitization has been shown to negatively affect post-heart transplant (HTx) survival even with a negative crossmatch. Whether allosensitization related to mechanical circulatory support (MCS) is associated with worse post-HTx survival remains controversial.

METHODS

Adult HTx recipients listed in the United Network for Organ Sharing database (July 2006-December 2012) were identified. Multivariate Cox regression assessed the effect of allosensitization on survival. Propensity matching was performed to compare patients who were and were not allosensitized. Kaplan-Meier survival analysis compared matched and unmatched patients in the MCS and medically managed cohorts.

RESULTS

We identified 11,840 HTx recipients, of whom 4,167 had MCS. MCS was associated with allosensitization in multivariate logistic regression. Each different MCS device was associated with worse post-HTx survival in multivariate Cox regression. Allosensitization did not predict post-HTx mortality in MCS patients (hazard ratio, 1.07; 95% confidence interval, 0.89-1.28; p = 0.48. Among patients without MCS, allosensitization was associated with post-HTx mortality (hazard ratio, 1.19; 95% confidence interval, 1.03-1.39; p = 0.02). Kaplan-Meier analysis revealed equivalent survival in unmatched and matched cohorts when MCS patients who were allosensitized were compared with non-allosensitized MCS patients. Among non-MCS patients, allosensitization was associated with worse survival in unmatched and matched analysis.

CONCLUSIONS

MCS was associated with allosensitization. For MCS patients, allosensitization did not independently predict worse post-HTx outcome. Among non-MCS patients, allosensitization was associated with worse post-HTx survival. Allosensitization appears to be a heterogeneous process influenced by presence of MCS.

Cardiac transplantation for older patients: Characteristics and outcomes in the septuagenarian population

BACKGROUND

With increasing age of patients with heart failure, it is important to understand the potential role for orthotopic heart transplant (OHT) in elderly patients. We examined recipient and donor characteristics and long-term outcomes of older recipients of OHT in the United States.

METHODS

Using the United Network for Organ Sharing database, we identified OHT recipients from the years 1987-2014 and stratified them by age 18-59 years old, 60-69 years old, and ≥70 years old. We compared baseline characteristics of recipients and donors and assessed outcomes across groups.

RESULTS

During this period, 50,432 patients underwent OHT; 71.8% (n = 36,190) were 18-59 years old, 26.8% (n = 13,527) were 60-69 years old, and 1.4% (n = 715) were ≥70 years old. Comparing the ≥70 years old group and 60-69 years old group, older patients had higher rates of ischemic etiology (53.6% vs 44.9%) and baseline renal dysfunction (61.4% vs 56.4%) and at the time of OHT were less likely to be currently hospitalized (45.0% vs 50.9%) or supported with left ventricular assist device therapy (21.0% vs 28.3%). Older recipients received organs from older donors (median age 36 years old vs 30 years old) who were more likely to have diabetes and substance use. After OHT, the median length of stay was similar between groups. At 1 year, of patients alive, patients ≥70 years old had fewer rejection episodes (17.8%) compared with patients 60-69 years old (29.5%). The 5-year mortality was 26.9% for recipients 18-59 years old, 29.3% for recipients 60-69 years old, and 30.8% for recipients ≥70 years old.

CONCLUSIONS

Despite advanced age and less ideal donors, OHT recipients in their 70s had similar outcomes to recipients in their 60s. Selected older patients should not routinely be excluded from consideration for OHT.

Adult heart transplant: indications and outcomes

Cardiac transplantation is the treatment of choice for many patients with end-stage heart failure (HF) who remain symptomatic despite optimal medical therapy. For carefully selected patients, heart transplantation offers markedly improved survival and quality of life. Risk stratification of the large group of patients with end-stage HF is essential for identifying patients who are most likely to benefit, particularly as the number of suitable donors is insufficient to meet demand. The indications for heart transplant and review components of the pre-transplant evaluation, including the role for exercise testing and risk scores such as the Heart Failure Survival Score (HFSS) and Seattle Heart Failure Model (SHFM) are summarized. Common contraindications are also discussed. Outcomes, including survival and common complications such as coronary allograft vasculopathy are reviewed.

Does renal dysfunction and method of bridging support influence heart transplant graft survival?

BACKGROUND

Renal insufficiency is common in status 1B patients supported with inotropes or a continuous flow left ventricular device (CF-LVAD) as a bridge to heart transplantation. We evaluated the association of renal function and inotrope versus CF-LVAD support on posttransplant graft survival in status 1B patients.

METHODS

The Scientific Registry for Transplant Recipients database was analyzed for posttransplant survival in status 1B patients bridged with inotropes or CF-LVAD who underwent transplantation between 2003 and 2012. Pretransplant renal function was measured by estimating glomerular filtration rate (GFR) and was stratified as less than 45 mL · min(-1) · 1.73 m(-2), 45 to 59, and 60 or greater. Univariate Kaplan-Meier and multivariate Cox regression models were used to evaluate the main effects of GFR strata and inotropes versus CF-LVAD, and the interaction effect of GFR strata by CF-LVAD, on graft survival.

RESULTS

This study included 4,158 status 1B patients (74% male, aged 53 ± 12 years). Of those, 659 patients had a CF-LVAD (HeartMate-II [Thoratec, Pleasanton, CA], n = 638; HVAD [HeartWare, Framingham, MA], n = 21), and 3,530 were receiving inotropes (31 CF-LVAD patients were also receiving inotropes). Kaplan-Meier analyses demonstrated reduced graft survival (p = 0.022) in patients with pretransplant GFR less than 45 versus GFR 45 to 59 (p = 0.062) and versus GFR 60 or greater (p = 0.007), and no effect of inotrope versus CF-LVAD support on graft survival (p = 0.402). Multivariate analysis demonstrated that, after adjusting for the main effects of GFR stratum, CF-LVAD, and inotropes, status 1B patients bridged with a CF-LVAD and GFR in the lowest stratum had reduced graft survival (interaction effect p = 0.040).

CONCLUSIONS

Pretransplant renal insufficiency was associated with reduced posttransplant graft survival in status 1B patients. This risk is increased for patients bridged with a CF-LVAD (versus inotropes) who have GFR in the lowest stratum.