Impact of Heart Transplantation on Survival in Patients on Venoarterial Extracorporeal Membrane Oxygenation at Listing in France

Perioperative Venoarterial Extracorporeal Membrane Oxygenation Support During Heart Transplant

OBJECTIVES

Heart transplant is the only definitive treatment of end-stage heart failure. Venoarterial extracorporeal membrane oxygenation may be used as a bridge to heart transplant. This technique may be used after heart transplant for conditions refractory to medical treatment like primary graft failure. Previously, we reported our experience with patients who received extracorporeal support as a bridge to emergency heart transplant. In this study, we present our perioperative experience with heart transplants in which extracorporeal support was used.

MATERIALS AND METHODS

We retrospectively screened the data of 31 patients who were seen at our center between January 2014 and June 2016. We screened for patients who were admitted tothe intensive care unit before transplant and who required venoarterial extracorporeal membrane oxygenation for circulatory support and postoperative patients who required extracorporeal support. Patient demographics and characteristics, clinical data, and extracorporeal support data were collected from our electronic database and patient medical records.

RESULTS

There were 14 patients who required perioperative extracorporeal support. Preoperative support was performed in 3 patients before transplant, and postoperative support was performed in 11 patients after transplant. The mean age was 37.7 years in patients within the preoperative group and 29.7 years in patients within the postoperative group. One patient with preoperative support and 5 with postoperative support were pediatric patients. The main indication for transplant was dilated cardiomyopathy in both groups (100% and 63.7%). Overall mortality rates were 33% in the preoperative group and 63.7% in the postoperative group.

CONCLUSIONS

For patients on heart transplant wait lists who are worsening despite optimal medical therapy, venoarterial extracorporeal membrane oxygenation support is a safe and viable last resort. In addition, extracorporeal support can be used during the posttransplant period as salvage therapy in heart recipients with hemodynamic deterioration. In our experience, preoperative extracorporeal support had lower mortality rates compared with postoperative support.

Extracorporeal life support in preoperative and postoperative heart transplant management

Increased experience with extracorporeal life support (ECLS) as a mode of cardiac support has expanded its use to diverse patient populations including patients requiring a bridge to heart transplantation and patients requiring posttransplant support for primary graft dysfunction (PGD). The use of ECLS is associated with acceptable outcomes in well-selected patients. While outcomes with the use of extracorporeal membrane oxygenation (ECMO) as a bridge to heart transplant have been variable, several series have confirmed the safe use of ECLS to stabilize patients prior to left ventricular assist device (LVAD) implantation. These patients are then considered later, when in stable condition, for heart transplant. When ECLS is used prior to heart transplant, mortality is greatest during the first 6 months posttransplant. Patients who are alive 6 months after transplant appear to have similar survival rates as patients who were not supported with ECLS prior to transplant. ECLS support is a reliable therapeutic option for severe PGD and early graft failure after heart transplantation. In patients who require support for severe PGD, venoarterial-ECMO appears to result in better clinical outcomes than LVAD support. ECLS use for PGD after heart transplant continues to be the first line of support. Further studies are necessary to understand the optimal role of ECLS in heart transplantation.

Clinical outcomes of temporary mechanical circulatory support as a direct bridge to heart transplantation: a nationwide Spanish registry

BACKGROUND

In Spain, listing for high-urgent heart transplantation is allowed for critically ill candidates not weanable from temporary mechanical circulatory support (T-MCS). We sought to analyse the clinical outcomes of this strategy.

METHODS AND RESULTS

We conducted a case-by-case, retrospective review of clinical records of 291 adult patients listed for high-urgent heart transplantation under temporary devices from 2010 to 2015 in 16 Spanish institutions. Survival after listing and adverse clinical events were studied. At the time of listing, 169 (58%) patients were supported on veno-arterial extracorporeal membrane oxygenation (VA-ECMO), 70 (24%) on temporary left ventricular assist devices (T-LVAD) and 52 (18%) on temporary biventricular assist devices (T-BiVAD). Seven patients transitioned from VA-ECMO to temporary ventricular assist devices while on the waiting list. Mean time on T-MCS was 13.1 ± 12.6 days. Mean time from listing to transplantation was 7.6 ± 8.5 days. Overall, 230 (79%) patients were transplanted and 54 (18.6%) died during MCS. In-hospital postoperative mortality after transplantation was 33.3%, 11.9% and 26.2% for patients bridged on VA-ECMO, T-LVAD and T-BiVAD, respectively (P = 0.008). Overall survival from listing to hospital discharge was 54.4%, 78.6% and 55.8%, respectively (P = 0.002). T-LVAD support was independently associated with a lower risk of death over the first year after listing (hazard ratio 0.52, 95% confidence interval 0.30-0.92). Patients treated with VA-ECMO showed the highest incidence rate of adverse clinical events associated with T-MCS.

CONCLUSION

Temporary devices may be used to bridge critically ill candidates directly to heart transplantation in a setting of short waiting list times, as is the case of Spain. In our series, bridging with T-LVAD was associated with more favourable outcomes than bridging with T-BiVAD or VA-ECMO.

Dilated cardiomyopathy

Dilated cardiomyopathy is defined by the presence of left ventricular dilatation and contractile dysfunction. Genetic mutations involving genes that encode cytoskeletal, sarcomere, and nuclear envelope proteins, among others, account for up to 35% of cases. Acquired causes include myocarditis and exposure to alcohol, drugs and toxins, and metabolic and endocrine disturbances. The most common presenting symptoms relate to congestive heart failure, but can also include circulatory collapse, arrhythmias, and thromboembolic events. Secondary neurohormonal changes contribute to reverse remodelling and ongoing myocyte damage. The prognosis is worst for individuals with the lowest ejection fractions or severe diastolic dysfunction. Treatment of chronic heart failure comprises medications that improve survival and reduce hospital admission-namely, angiotensin converting enzyme inhibitors and β blockers. Other interventions include enrolment in a multidisciplinary heart failure service, and device therapy for arrhythmia management and sudden death prevention. Patients who are refractory to medical therapy might benefit from mechanical circulatory support and heart transplantation. Treatment of preclinical disease and the potential role of stem-cell therapy are being investigated.

Extracorporeal Membrane Oxygenation (ECMO) and the Critical Cardiac Patient

PURPOSE OF REVIEW

This review is to summarize the basics of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) as it is utilized for critically ill cardiac patients.

RECENT FINDINGS

ECMO may be instituted in a variety of health care settings, from the emergency room to the operating room. The types of patients who may benefit from ECMO are reviewed in detail. The complications of ECMO are reviewed, including access-related issues and hematologic and neurologic problems. The principles of weaning of ECMO are described.

CONCLUSION

Due to its versatility and relatively low cost, VA ECMO use is sharply increasing worldwide. It is important to select patients carefully for this mode of therapy as it can keep patients alive even in states of severe neurologic impairment or multiorgan failure. Short courses of ECMO may allow critically ill patients to be salvaged, but ultimately survival depends on resolution of the underlying problem or ability to transition to another more durable mode of cardiac support.

[Extracorporeal membrane oxygenation in critically ill neonates and children]

Extracorporeal membrane oxygenation is used as a last resort during neonatal and pediatric resuscitation in case of refractory circulatory or respiratory failure under maximum conventional therapies. Different types of ECMO can be used depending on the initial failure. The main indications for ECMO are refractory respiratory failure (acute respiratory distress syndrome, status asthmaticus, severe pneumonia, meconium aspiration syndrome, pulmonary hypertension) and refractory circulatory failure (cardiogenic shock, septic shock, refractory cardiac arrest). The main contraindications are a gestational age under 34 weeks or birth weight under 2kg, severe underlying pulmonary disease, severe immune deficiency, a neurodegenerative disease and hereditary disease of hemostasis. Neurological impairment can occur during ECMO (cranial hemorrhage, seizure or stroke). Nosocomial infections and acute kidney injury are also frequent complications of ECMO. The overall survival rate of ECMO is about 60 %. This survival rate can change depending on the initial disease: from 80 % for meconium aspiration syndrome to less than 10 % for out-of-hospital refractory cardiac arrest. Recently, mobile ECMO units have been created. These units are able to perform ECMO out of a referral center for untransportable critically ill patients.