Heart Transplantation in Patients Supported by ECMO: Is the APACHE IV Score a Predictor of Survival?

Prognostic Value of APACHE IV Score in Patients Bridged to Heart Transplantation on ECMO

BACKGROUND

Methods for risk stratification of candidates for heart transplantation (HTx) supported by extracorporeal membrane oxygenation (ECMO) are limited. We evaluated the reliability of the APACHE IV score to identify the risk of mortality in this patient subset in a multicenter study.

METHODS

Between January 2010 and December 2022, 167 consecutive ECMO patients were bridged to HTx; they were divided into two groups, according to a cutoff value of APACHE IV score, obtained by receiver operating characteristic curve analysis for 90-day mortality. Kaplan-Meier survival curves were plotted, and compared through the log-Rank test. Cox regression model was used to estimate which factors were associated with survival.

RESULTS

The 90-day mortality prediction of the APACHE IV score showed an area under the curve of 0.87 (95% CI: 0.80-0.94), with a cutoff value of 49 (specificity 91.7%-sensibility 69.6%). 125 patients (74.8%) showed an APACHE IV score value < 49 (Group A), and 42 (25.2%) ≥ 49 (Group B). 90-day mortality was 11.2% in Group A and 76.2% in Group B (p < 0.01). Survival at 1 and 5 years was 85.5%, 77% versus 23.4%, 23.4% (p < 0.01) in Groups A and B. Mortality correlated at univariable analysis with recipient age, body mass index, mechanical ventilation, APACHE IV score, and platelets number. At multivariable analysis only APACHE IV score (HR: 1.07 [1.05-1.09, 95% CI]) independently affected survival.

CONCLUSIONS

The APACHE IV score represents a powerful predictor of survival in patients bridged to HTx on ECMO support, and could guide candidacy of patients on ECMO.

Veno-arterial ECMO ventricular assistance as a direct bridge to heart transplant: A single center experience in a low-middle income country

INTRODUCTION

The use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) as a direct bridge to heart transplantation (BTT) is not common in adults worldwide. BTT with ECMO is associated with increased early/mid-term mortality compared with other interventions. In low- and middle-income countries (LMIC), where no other type of short-term mechanical circulatory support is available, its use is widespread and increasingly used as rescue therapy in patients with cardiogenic shock (CS) as a direct bridge to heart transplantation (HT).

OBJECTIVE

To assess the outcomes of adult patients using VA-ECMO as a direct BTT in an LMIC and compare them with international registries.

METHODS

We conducted a single-center study analyzing consecutive adult patients requiring VA-ECMO as BTT due to refractory CS or cardiac arrest (CA) in a cardiovascular center in Argentina between January 2014 and December 2022. Survival and adverse clinical events after VA-ECMO implantation were evaluated.

RESULTS

Of 86 VA-ECMO, 22 (25.5%) were implanted as initial BTT strategy, and 52.1% of them underwent HT. Mean age was 46 years (SD 12); 59% were male. ECMO was indicated in 81% for CS, and the most common underlying condition was coronary artery disease (31.8%). Overall, in-hospital mortality for VA-ECMO as BTT was 50%. Survival to discharge was 83% in those who underwent HT and 10% in those who did not, p < .001. In those who did not undergo HT, the main cause of death was hemorrhagic complications (44%), followed by thrombotic complications (33%). The median duration of VA-ECMO was 6 days (IQR 3-16). There were no differences in the number of days on ECMO between those who received a transplant and those who did not. In the Spanish registry, in-hospital survival after HT was 66.7%; the United Network of Organ Sharing registry estimated post-transplant survival at 73.1% ± 4.4%, and in the French national registry 1-year posttransplant survival was 70% in the VA-ECMO group.

CONCLUSIONS

In adult patients with cardiogenic shock, VA-ECMO as a direct BTT allowed successful HT in half of the patients. HT provided a survival benefit in listed patients on VA-ECMO. We present a single center experience with results comparable to those of international registries.

Comparison of Veno-arterial Extracorporeal Membrane Oxygenation Configurations for Patients Listed for Heart Transplantation

BACKGROUND AND OBJECTIVES

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) as a bridge to eventual heart transplantation (HT) is increasingly used worldwide. However, the effect of different VA-ECMO types on HT outcomes remains unclear.

METHODS

This was a retrospective observational study of 111 patients receiving VA-ECMO and awaiting HT. We assessed 3 ECMO configuration groups: peripheral (n=76), central (n=12), and peripheral to central ECMO conversion (n=23). Cox proportional hazards regression and landmark analysis were conducted to analyze the effect of the ECMO configuration on HT and in-hospital mortality rates. We also evaluated adverse events during ECMO support.

RESULTS

HT was performed in the peripheral (n=48, 63.2%), central (n=10, 83.3%), and conversion (n=11, 47.8%) ECMO groups (p=0.133) with a median interval of 10.5, 16, and 30 days, respectively (p<0.001). The cumulative incidence of HT was significantly lower in the conversion group (hazard ratio, 0.292, 95% confidence interval, 0.145-0.586, p=0.001). However, there was no difference in in-hospital mortality (log-rank p=0.433). In the landmark analysis, in-hospital mortality did not differ significantly among the 3 groups. Although we did note a trend toward lower HT in the conversion group, the difference was not statistically significant. Surgical site bleeding occurred mainly in the central, while limb ischemia occurred mainly in the peripheral groups.

CONCLUSIONS

We suggest that if patients are being stably supported with their initial ECMO configuration, whether it is central or peripheral, it should be maintained, and ECMO conversion should only be cautiously performed when necessary.

Veno-Arterial Extracorporeal Membrane Oxygenation as a Bridge to Heart Transplant-Change of Paradigm

Despite advances in medical therapy and mechanical circulatory support (MCS), heart transplant (HT) remains the gold standard therapy for end-stage heart failure. Patients in cardiogenic shock require prompt intervention to reverse hypoperfusion and end-organ damage. When medical therapy becomes insufficient, MCS should be considered. Historically, it has been reported that critically ill patients bridged with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) directly to HT have worse outcomes. However, when the heart allocation system gives the highest priority to patients on VA-ECMO support, those patients have a higher incidence of HT and a lower incidence of death or removal from the transplant list. Moreover, patients with a short waiting time on VA-ECMO have a similar hazard of mortality to non-ECMO patients. According to the reported data, bridging with VA-ECMO directly to HT may be a solution in the selection of critically ill patients when the anticipated waiting list time is short. However, when a prolonged waiting time is expected, more durable MCS should be considered. Regardless of the favorable results of the direct bridging to HT with ECMO in selected patients, the superiority of this strategy compared to the bridge-to-bridge strategy (ECMO to durable MCS) has not been established and further studies are mandatory in order to clarify this issue.

Extracorporeal membrane oxygenation as a bridge to durable mechanical circulatory support or heart transplantation

BACKGROUND

Patients with cardiogenic shock may require extracorporeal membrane oxygenation (ECMO) prior to durable mechanical circulatory support (dMCS) or heart transplantation (HTx).

METHODS

We investigated the clinical characteristics and outcomes of adult patients with ECMO support as bridge to dMCS or HTx between 1/1/13 and 12/31/20.

RESULTS

Of 57 patients who underwent bridging ECMO, 41 (72%) received dMCS (approximately half with biventricular support) and 16 (28%) underwent HTx, 13 (81%) after the 2018 UNOS allocation system change. ECMO → HTx patients had shorter ventilatory time (3.5 vs 7.5 days; p = 0.018), ICU stay (6 vs 18 days; p = 0.001), and less need for inpatient rehabilitation (18.8% vs 57.5%; p = 0.016). The 1-year survival post HTx was 81.3% in the ECMO → HTx group and 86.4% in the ECMO → dMCS group (p = 0.11). For those patients in the ECMO → dMCS group who did not undergo HTx, 1-year survival was significantly lower, 31.6% (p = 0.001).

CONCLUSION

Patients on ECMO who undergo HTx, with or without dMCS bridge, have acceptable post-HTx survival. These findings suggest that HTx from ECMO is a viable option for carefully selected patients deemed acceptable to proceed with definitive advanced therapies, especially in the era of the new UNOS allocation system.

Association between the Predicted Value of APACHE IV Scores and Intensive Care Unit Mortality: A Secondary Analysis Based on EICU Dataset

Objective

The evidence regarding the relationship between Acute Physiological and Chronic Health Assessment (APACHE) IV scores and emergency intensive care unit (EICU) mortality in patients following organ transplantation remains controversial. The purpose of this study was to investigate the relationship between APACHE IV score and EICU mortality.

Methods

Data from 391 American men and women admitted to the EICU after undergoing organ transplants including heart, bone marrow, liver, kidney, lung, and pancreas in the United States. We used this data to analyze the relationship between APACHE IV scores and in-hospital mortality in the postoperative EICU. The primary endpoint was ICU hospitalization mortality after organ transplantation. The entire study data was extracted from the EICU database and uploaded to the DataDryad website.

Results

Interaction tests indicate age, respiratory failure, and hormone use can modify the association between APACHE IV and EICU mortality. A stronger association of APACHE and mortality can be observed at <60 years old, no respiratory failure, and no use of hormones. In contrast, there was no association between respiratory failure, hormone use, APACHE, and ICU mortality in patients over 60 years of age.

Conclusion

When using the APACHE score for risk stratification of critically ill patients after transplantation, the patient's age, respiratory failure, and use of hormones should be taken into account.

Contemporary contribution of cardiac surgery for the treatment of cardiomyopathies and pericardial diseases

Cardiomyopathy refers to a spectrum of heterogeneous myocardial disorders characterized by morphological and structural alterations leading eventually to heart failure, by affecting cardiac filling and/or the cardiac systolic function. Heart transplantation is currently the gold standard surgical treatment for patients with heart failure, with a median survival in adults of 12 years according to international registries. However, the limited available donor pool does not allow its extensive employment. For this reason, mechanical circulatory supports are increasingly used, and in the short term are becoming as possible alternatives to heart transplantation, owing to improved technologies and increased biocompatibility. However, long-term outcomes of mechanical assist devices are still burdened with a high rate of adverse events. Conventional surgical treatments could be still considered as alternatives to heart replacement treatment when tailored both on patient clinical conditions and etiology of cardiac diseases. In particular, among patients affected by ischemic cardiomyopathy, coronary artery bypass grafting has proven to improve survival when associated to optimal medical treatment, and surgical ventricular restoration might be considered as a valid treatment in particular cases. Correction of functional mitral valve regurgitation by mitral annuloplasty, which aims to restore left ventricular geometry, has not demonstrated unambiguous results, and outcomes of this procedure are still controversial. Pericardial pathology becomes of surgical interest when it is responsible for a reduced filling capacity of the heart chambers, which can develop acutely (cardiac tamponade) or chronically (as in the case of constrictive pericarditis). This review focuses on the different surgical approaches that could be adopted to treat patients with heart failure and pericardial diseases.

Veno-arterial Extracorporeal Membrane Oxygenation as Bridge to Heart Transplantation: The Way Forward

Advanced heart failure (HF) represents a public health priority due to the increase of affected patients and the meaningful mortality. Durable mechanical circulatory support (MCS) and heart transplantation (HTx) are unique therapies for end-stage HF (ESHF), with positive early and long-term outcomes. The patients who underwent HTx have a 1-y survival of 91% and a median survival of 12-13 y, whereas the median survival of ESHF is <12 mo. Short-term MCS with veno-arterial extracorporeal membrane oxygenation (VA ECMO) can be used as a bridge to transplantation strategy. Patients bridged with VA ECMO have significantly lower survival in comparison with non-MCS bridged and left ventricular assist device-bridged patients. VA ECMO represents an effective, and sometimes unique, system to obtain rapid hemodynamic stabilization, but possible negative effects on patients' outcomes after HTx must be considered. Here, we discuss the use of VA ECMO as bridge to transplantation.

Heart transplant outcomes in patients with mechanical circulatory support: cold storage versus normothermic perfusion organ preservation

OBJECTIVES

Patients with mechanical circulatory support bridged to a heart transplant (HTx) are at higher risk of postoperative graft dysfunction. In this subset, a mode of graft preservation that shortens graft ischaemia should be beneficial.

METHODS

The outcomes of 38 patients on mechanical circulatory support (extracorporeal life support, left ventricular assist device and biventricular assist device) who received a HTx between 2015 and 2020 were analysed according to the method of graft preservation: cold storage (CS) group, 24 (63%) or ex vivo perfusion (EVP) group, 14 (37%).

RESULTS

The median age was 57 (range 30-73) vs 64 (35-75) years (P = 0.10); 88% were men (P = 0.28); extracorporeal life support was more frequent in the CS group (54% vs 36%; P = 0.27) versus left ventricular and biventricular assist devices in the EVP group (46% vs 64%; P = 0.27). Clamping time was shorter in the EVP group (P < 0.001) and ischaemic time >4 h was higher in the CS group (P = 0.01). Thirty-day mortality was 13% (0-27%) in the CS group and 0% (P = 0.28) in the EVP group. A significantly lower primary graft failure [7% (0-23%) vs 42% (20-63%); P = 0.03] was observed in the EVP group. Survival at 1 year was 79 ± 8% (63-95%) in the CS group and 84 ± 10% (64-104%) in the EVP group (P = 0.95).

CONCLUSIONS

Our results support the use of ex vivo graft perfusion in patients on mechanical circulatory support as a bridge to a HTx. This technique, by shortening graft ischaemic time, seems to improve post-HTx outcomes.

Influence of donor-transmitted coronary artery disease on long-term outcomes after heart transplantation - a retrospective study

BACKGROUND

Cardiac allograft vasculopathy (CAV) is an important cause of late mortality after heart transplantation, which may be influenced by preexisting coronary disease (CAD) in the donor heart.

METHODS

The aim of this study was to verify whether CAD in the donor heart had any influence on survival, cardiac-related adverse events (CRAEs), and coronary disease progression after transplantation. Donor coronary angiography performed in 289 hearts showed absence of CAD in 232 (no-CAD group) and moderate (≤50%) stenoses (CAD group) in 57. The 2 groups were compared for survival, freedom from CRAEs, and development of grade ≥ 2 CAV after transplantation.

RESULTS

Of 30-day mortality and postoperative complication rate was similar as mean follow-up (76 ± 56 and 75 ± 55 months) for no-CAD and CAD (P = 0.8). Ten-year actuarial survival was 58 ± 4% and 62 ± 7% for no-CAD and CAD (P = 0.4). Ten-year freedom from grade ≥ 2 CAV and from CRAEs was 81 ± 4% and 66 ± 5% vs 75 ± 8% and 67 ± 9% in no-CAD and CAD (P = 0.9 and 0.9, respectively).

CONCLUSIONS

Donor hearts with moderate CAD did not affect survival, freedom from CRAEs and did not accelerate development of high-grade CAV after transplantation supporting the use of such grafts to expand the donor pool. Routine use of coronary angiography in donor selection appears justified.

Bridge to heart transplantation in patients with cardiogenic shock: a 20-year experience with two different surgical strategies

AIMS

We aimed to describe how treatment of patients in cardiogenic shock bridged to heart transplantation with mechanical circulatory support, using either biventricular assist devices (BVADs) or extracorporeal life support (ECLS), has evolved in the last 20 years in our centre.

METHODS

Since 1998, 72 patients with refractory heart failure and indication for heart transplantation have received mechanical circulatory support: 40 had an ECLS system and 32 a BVAD.

RESULTS

Early mortality was similar (17.5 vs. 9.4%, P = 0.25) regardless of the type of support. After a median support time of 8 (1-27) vs. 34 (0-385) days (P < 0.01), 70 vs. 65.6% (P = 0.69) of patients underwent transplantation in the two groups. Prior to transplantation, BVAD patients were more stable with lower need for mechanical ventilation (9 vs. 57%, P < 0.01) and dialysis (0 vs. 38%, P < 0.01). Thirty-day mortality after transplantation was similar (18 vs. 14%, P = 0.53). Patients with extracorporeal support had higher rates of renal (P = 0.02) and respiratory failure (P = 0.03), infections (P = 0.02), atrial fibrillation (P = 0.03) and longer ICU stay (P = 0.01). Late survival was similar, while 5-year freedom from coronary vasculopathy was higher in those with BVAD (P = 0.03).

CONCLUSION

Although ECLS provides faster and simpler assistance compared with BVADs, no differences in early and medium-term outcomes in the last 20 years were observed in patients with cardiogenic shock. However, BVADs provided longer duration of support, better multiorgan recovery allowing more adequate graft selection, resulting in a lower rate of posttransplant complications.

What are the results of venoarterial extracorporeal membrane oxygenation bridging to heart transplantation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether heart transplantation is a viable treatment option in patients in refractory cardiogenic shock who could not be weaned off venoarterial extracorporeal membrane oxygenation (VA ECMO). Altogether, 373 papers were found using the reported search, of which 7 papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Evidence is derived from 3 papers based on registry analysis, 1 multi-institutional study and 3 single-institution reviews. Early post-transplant mortality of ECMO-bridged recipients ranges from 18.7% to 33.3% and 1-year survival from 44.6% to 72.0%. High acuity of recipient illness reflected by poor renal function, mechanical ventilation, advanced age, elevated serum lactate predict inferior outcome. We conclude that heart transplantation results in patients bridged with VA ECMO are inferior when compared to published outcome of non-bridged recipients. In the era of severe organ shortage and intense public and regulatory scrutiny of the results, the decision to transplant a patient directly of VA ECMO needs to be made on a case-by-case basis. Potential gain in decreasing the waiting list mortality of these critically ill patients needs to be weighed against poorer post-transplantation mortality rates and mid- and long-term outcomes.

Veno-Arterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock

Extracorporeal membrane oxygenation has evolved, from a therapy that was selectively applied in the pediatric population in tertiary centers, to more widespread use in diverse forms of cardiopulmonary failure in all ages. We provide a practical review for cardiovascular clinicians on the application of veno-arterial extracorporeal membrane oxygenation in adult patients with cardiogenic shock, including epidemiology of cardiogenic shock, indications, contraindications, and the extracorporeal membrane oxygenation circuit. We also summarize cannulation techniques, practical management and troubleshooting, prognosis, and weaning and exit strategies, with attention to end of life and ethical considerations.

Five years' experience with a peripheral veno-arterial ECMO for mechanical bridge to heart transplantation

Background

Mechanical circulatory support (MCS) is the only way to save a life for heart transplant candidates and to decrease of waiting list mortality. The choice between short- or long-term pretransplant MCS depends on of type and severity of CHF. One of the most frequently used methods of temporary MSC before orthotopic heart transplantation (OHTx) is veno-arterial extracorporeal membrane oxygenation (VA ECMO). The aim of this study was to analyze own experience of peripheral VA ECMO (pVA ECMO) in heart transplant candidates needed in urgent HT.

Methods

This study included 182 pts [160 (87.9%) men and 22 (12.1%) female, age 43±1.2 yrs] supported with pVA ECMO in the period from 01. 01. 2013 to 31. 12. 2017 or 23.2% from all waiting list (n=786).

Results

During VA ECMO, 16 (8.8%) of the 182 pts died. In most pts [n=13 (81.3%)] multiorgan failure/sepsis were the cause of death. One hundred and sixty-six (91.2%) pts were successfully bridged to OHTx or 27.9% from all heart transplant recipients (n=594) (2013-2017 yrs). The duration of pVA ECMO before OHTx (n=166) was 5.8±3.2 days. One hundred and forty-three (86.1%) from 166 pts were discharged to home. Post-transplant survival among heart transplant recipient with pre-transplant MCS by pVA ECMO was in comparison with recipients without pretransplant MCS [84.2% vs. 90.1% (6 months), 83.3% vs. 91.8% (1 years), 75.1% vs. 86.1% (2 years), 74.2% vs. 85.8% (3 years), 72.3% vs. 84.7% (4 years), 72.3% vs. 83.5% (5 years) respectively (P<0.0001)].

Conclusions

pVA ECMO is a useful tool of treatment of patients with INTERMACS profile 1/2. Results of OHTx at recipients bridged with VA ECMO are less successful that recipients without pre-transplant MCS. VA ECMO should be considered as a direct bridge to OHTx in conditions of limited financial resources of health care and high availability of donor's hearts.

Artificial Organs 2018: A Year in Review

In this Editor's Review, articles published in 2018 are organized by category and summarized. We provide a brief reflection of the research and progress in artificial organs intended to advance and better human life while providing insight for continued application of these technologies and methods. Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. Peer-reviewed special issues this year included contributions from the 13th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion edited by Dr. Akif Undar, and the 25th Congress of the International Society for Mechanical Circulatory Support edited by Dr. Marvin Slepian. Additionally, many editorials highlighted the worldwide survival differences in hemodialysis and perspectives on mechanical circulatory support and stem cell therapies for cardiac support. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.