Postoperative Mechanical Support Research Articles

The Ross and Ross-Konno Operation in Neonates and Infants

When replacement of the aortic valve in neonates and infants is required, the Ross-Konno procedure provides a high-quality left ventricular outflow with good mid-term durability. The procedural outcome is highly dependent on the pre-procedural condition of the neonate or infant. Most series contain substantial numbers of post-balloon valvotomy patients as emergent or urgent management of severe, acute regurgitation. In patients with compromised ventricular function, post-operative mechanical support may be required but is generally associated with a good outcome. The neonatal and infant autograft may perform better in the long term than un-supported autografts performed later in life. Early definitive or delayed treatment of left ventricular outflow tract pathology associated with aortic interruption increasingly involves an infant Ross-Konno. The procedure also has a role in the recruitment of small left ventricles. Concomitant mitral pathology or aortic obstruction magnifies complexity, but the operative approach to the Ross-Konno remains the same.

Re-dosing of del Nido cardioplegia in adult cardiac surgery requiring prolonged aortic cross-clamp.

OBJECTIVESFew data exist on the use of del Nido cardioplegia in adults, specifically during operations requiring prolonged aortic cross-clamp. In this pilot study, we evaluate outcomes of patients undergoing surgery with cross-clamp time >3 h based on re-dosing strategy, using either full dose (FD; 1:4 blood to crystalloid ratio) or dilute (4:1 blood to crystalloid ratio) solution.METHODSConsecutive adult patients (>18 years) undergoing cardiac surgery from 2012 to 2018 with cross-clamp time >3 h were reviewed. Patients were excluded if del Nido cardioplegia was not used. Patients were categorized into FD or dilute groups based on re-dosing solution. Propensity score matching was used to control for baseline differences between groups. The primary endpoint was in-hospital mortality. Other outcomes examined included: postoperative mechanical support, arrhythmia, stroke, dialysis and cardiac function.RESULTSIncluded for analysis were 173 patients (115 male) with median age of 63.8 (interquartile range 53.9–73.1). Major comorbidities included diabetes (45), cerebrovascular disease (34), hypertension (131), atrial fibrillation (52) and previous cardiac surgery (83). There were 108 patients (62%) who received FD re-dosing, while 65 (38%) received dilute. A greater proportion of patients in the dilute group received retrograde delivery, for both induction (32/108 vs 39/65, P < 0.001) and re-dose (50/108 vs 53/65, P < 0.001). After propensity score matching, in-hospital mortality was not different between groups (6/48 vs 1/48, P = 0.131). There were no differences in rates of postoperative mechanical circulatory support, stroke, left ventricular ejection fraction or right ventricle dysfunction.CONCLUSIONSDel Nido cardioplegia has been used in complex cardiac surgery requiring prolonged cross-clamp. Re-dosing can be performed with either FD or dilute del Nido solution with no statistical difference in outcomes.

Pediatric Heart Transplantation Following Donation after Circulatory Death, Distant Procurement and Ex-Situ Perfusion

Purpose There remains a significant shortage of organs for children listed for heart transplant. This may be ameliorated by controlled donation after circulatory death (DCD), which has proven success in adults. However, there are numerous challenges in retrieval, assessment and transportation of DCD hearts. We report a unique collaboration between 2 centres, combining expertise in DCD organ retrieval and paediatric transplantation. Methods All families of children over 20 kg listed for heart transplantation were approached for DCD listing; all consented (n = 20). DCD hearts were procured by direct retrieval and perfusion, and then mounted, perfused and assessed on an ex-situ cardiac perfusion machine (Organ Care System (OCS), TransMedics, Inc., Andover, MA), before transfer to the implanting unit. Results Between 1 Feb and 30 Jun 2020, 5 children received a DCD heart (aged 12 to 16 years; two female). Two had previous cardiac surgery, and none had transpulmonary gradient > 8 mmHg. Donor median age was 19.5 years (15-43); three were male. Donor heart mean functional warm ischaemic time was 25 minutes (22 - 28). Mean travel distance was 150 miles (40 - 220) and mean ex-situ perfusion time was 266 minutes (192 - 325). Initial arterial lactate on the OCS was 8.8 mmol/l (4.7-11.7) and venous 8.0 mmol/l (4.7 - 10.1); these fell to 4.7 mmol/l (2.2 - 7.4) and 4.4 mmol/L (2 - 7.1) respectively during transport. No recipients required post-operative mechanical support. Median ITU stay was 8 days (7 - 11) and total hospital stay was 16 days (12 - 21). Pre-discharge echocardiography showed good biventricular function in all recipients except one with mild left and moderate right ventricular dysfunction; all now have excellent graft function. In the same period, 6 DBD transplants were performed in those listed for DCD; although not reaching statistical significance, ventilation, inotrope use, ITU and hospital stay were all shorter in the DCD group. Conclusion The use of previously unavailable DCD hearts has increased transplant activity by 83% in children > 20 kg in this early series. By combining the expertise of one unit in organ retrieval using novel technologies with another in paediatric transplantation, all patients had excellent short-term outcomes. Development of the DCD program to include the use of smaller organs is now a priority for both units.

Ross Operation in Neonates: A Meta-analysis

The Ross operation is the preferred treatment for aortic valve replacement in children. However previous studies indicate that outcomes in neonates are poor. This meta-analysis examines the pooled outcomes of the Ross operation in neonates. Four major databases (PubMed/MEDLINE, EMBASE, Scopus, and ScienceDirect) were searched from inception until May 1, 2020 for studies describing outcomes of the Ross operation in neonates. The primary outcome was early mortality, and secondary outcomes were late mortality and mechanical support. Random-effects models were used to account for possible heterogeneity between studies, and continuity corrections were used to include zero total event trials. Eighteen studies comprising outcomes data on 181 neonates were included in the analysis. Meta-analysis showed a pooled early mortality rate of 24% (95% confidence interval, 12%-38%; I2= 52%, P for heterogeneity= .01). Meta-regression analysis showed that more recently published studies reported significantly worse early mortality (P= .03). The pooled incidence of postoperative mechanical support was 15% (95% confidence interval, 5%-28%; I2= 28%, P for heterogeneity= .22). No evidence of publication bias was found according to Egger's test (bias coefficient= 0.21, P= .57). The neonatal Ross operation carries a high early mortality rate. The treatment of unrepairable aortic valves in neonates remains an unsolved problem in congenital cardiac surgery.

The challenges of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock.

Postcardiotomy cardiogenic shock describes the syndrome of refractory cardiac performance following cardiac surgery. The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for the management of postcardiotomy cardiogenic shock is controversial, and there are at least three scenarios where it may be necessary: first, pre-emptive postoperative VA-ECMO, where the decision for postoperative mechanical support is made prior to surgery, for example, in the context of poor pre-operative cardiac function; second, early yet unplanned post-cardiopulmonary bypass VA-ECMO following a long duration of cardiopulmonary bypass due to, for example, unexpected surgical complications; third, late rescue VA-ECMO following several attempts at weaning, either immediately following cardiopulmonary bypass or following transfer to the intensive care unit. The use of mechanical circulatory support for postcardiotomy cardiogenic shock is further complicated by the wide range of available devices, the availability of VA-ECMO in different centres, variations in experience and expertise as a function of local VA-ECMO workload, and regional variations in the diagnosis and management of postcardiotomy cardiogenic shock. Furthermore, survival appears to be low for such patients and it is not yet possible to predict who will survive. Many questions remain, however, such as those in relation to practices around patient selection, how best to study long-term outcomes, the ethics and efficacy of ECMO in such patients, and on all aspects of clinical decision-making. This review sets these clinical challenges in the context of the available evidence, including that from our centre.

Long-Term Outcome of Heart Transplant Recipients with Acute Graft Dysfunction Requiring Temporary Mechanical Circulatory Support

Mechanical circulatory support for acute graft dysfunction in heart transplant recipients is associated with increased early mortality and morbidity. Long-term outcome in patients who are successfully discharged from hospital is less well known. We performed a retrospective review of results in all adult patients (age > 18) who received first time heart transplant at our institution between 2007 and 2017. We compared graft survival and freedom from acute cellular and antibody mediated rejection of 90-day survivors who required mechanical support for graft failure with those who did not. We performed 243 first time adult heart transplantations over the study period with 6% 90-day mortality and 68±5% 5-year patient survival. (62±5% graft survival with 4 patients necessitating re-transplantation for severe CAV). Short-term outcome of patients supported with various types of MCS is depicted in Table 1. Five-year graft survival, freedom from ACR and freedom from AMR was 87±3%, 82±3% and 92±2% in patients without the need for post-transplant MCS and 53±15%, 49±17% and 75±13% in patients requiring MCS (Figure 1). Heart transplant recipients who require post-operative mechanical support and survive 90 days experience decreased long-term survival and less freedom from both acute cellular and antibody mediated rejection.

Histidine-Tryptophan-Ketoglutarate Solution for Donor Heart Preservation Is Safe for Transplantation

Various solutions are used for donor heart preservation. We examined the outcomes in our heart transplant population where histidine-tryptophan-ketoglutarate (HTK) solution has been used for heart preservation since2004. This was a retrospective review of the United Network for Organ Sharing (UNOS) database (2004-2016) comparing our heart transplant outcomes with other national centers. Propensity matching in a 1:3 ratio was performed to adjust for preoperative recipient variables. After propensity matching comparing UNOS outcomes (n= 1080) with our institutional data (n= 360), there was no difference in matched preoperative variables. Donor hearts were similar for donor age, sex, donor-to-recipient size ratio, LVEF, and ischemic time. Our HTK cohort had a larger proportion with donor cardiac arrest (26.3% vs 6.1%, P < .001) and longer cardiac arrest duration (22.1 ± 16.0 vs 17.2 ± 14.0 minutes, P=.052). Our primary graft dysfunction (PGD) rate requiring mechanical support was 4.2% (n= 1). Postoperative mechanical support use for PGD included extracorporeal membrane oxygenation in 9 (60.0%), intraaortic balloon pump in 4 (26.7%), right ventricular assist device in 3 (20%), and biventricular assist device in 3 (20%). Overall survival at our institution was similar to the national average (P= .649). Survival at 1, 5, and 10 years with HTK was 92.2%, 81.3%, and 70.8%, and for the UNOS population was 91.6%, 80.3%, and 62.0%, respectively. Use of HTK solution for donor hearts was associated with a low rate of severe PGD. Overall survival was not significantly different from other institutions using a variety of preservation solutions in the UNOS database during the same period. HTK solution is efficacious for preservation of donor hearts.

Efficacy of HTK Solution in the Preservation of Donor Hearts

Purpose Various preservation solutions for donor hearts are used nationally. We examined transplant outcomes where we used Histidine-tryptophan-ketoglutarate (HTK) solution exclusively since 2004. Methods Retrospective review of UNOS registry comparing our heart transplant outcomes with national outcomes since 2004. Propensity matching (1:3) was performed for donor and recipient age, gender, size, ischemic time , ejection fraction , prior cardiac surgery, heart failure etiology, concomitant kidney/liver transplantation, preop creatinine and preop mechanical support. Survival and postoperative outcomes were examined. We excluded pre-transplant extra-corporeal membrane oxygenation (ECMO), cardiac re-transplantation , heart-lung transplantation , and age less than 18. Results Our heart transplant population had a higher portion of patients with preoperative left ventricular assist device (56.9% vs 32.7%, P 0.05). There was no difference in survival between our institution and the national cohort (figure, P=0.649). Survival at 1, 5 and 10 years at our institution was 92.2%, 81.3%, and 70.8%, and for the UNOS population was 91.5%, 80.2%, and 62.0%. Our institution had a lower incidence of postoperative stroke (1.1% vs 3.1%, P=0.043) and new postoperative dialysis (5.6% vs 9.3%, P=0.028). The Michigan primary graft dysfunction (PGD) rate requiring mechanical support was 4.2%. Postoperative mechanical support utilized for PGD included ECMO (60.0%), right ventricular assist device (33.3%), intra-aortic balloon pump (20.0%), LVAD (13.3%), and biventricular support (13.3%). Conclusion Our exclusive use of HTK solution for donor heart preservation was associated with a low rate of PGD requiring mechanical support. Survival was non-inferior to the national outcomes. HTK is efficacious in preserving donor heart function.

Extended donor criteria in heart transplantation: a retrospective study from a single Chinese institution.

Heart donor selection criteria have been progressively widened due to increasing donor recipient mismatch. This study evaluates the outcomes of the use marginal donor hearts for orthotopic heart transplantation (OHT) based on a single center experience in China. We retrospectively analyzed outcomes of patients undergoing OHT in our hospital between September 2008 and December 2015. All the donor hearts were from voluntary donation of brain-dead patients. The primary outcome was overall survival; secondary outcomes included cardiopulmonary bypass (CPB) time, ventilation time, post-operative mechanical support and medium-term complications. Overall, 278 patients with OHT were analyzed. Whereas 180 patients (64.7%) underwent OHT utilizing marginal donors (MD group), only 98 patients (35.3%) underwent OHT with standard donors (SD group). Compared to the SD group, the MD group had longer CPB time (P=0.001), ventilation time (P=0.010) and increased mechanical support rate (P=0.011). Survival rates were comparable between the two groups at 30 days, 1 year, 3 years and 5 years (92.2%, 83.3%, 70.6%, 70.6% vs. 95.9%, 91.4%, 80.2%, 80.2% respectively). Multivariate Cox regression analysis revealed that female recipient gender [hazard ratio (HR) =2.632 (1.325-5.227), P=0.006], diagnosis (P=0.014) and abnormal donor heart structure [HR =3.638 (1.005-13.167), P=0.049] were three predictors for 1-year all-cause mortality. The occurrence of complications in the recipients with more than 3-year follow-up did not differ between the two cohorts. Marginal donor can be reasonably applied to expand the benefits of transplantation. Changing previous MD criteria to include donors with an age greater than 50 years, cold ischemic time less than 6 hours, donor/recipient weight ratio less than 0.8, compatible blood type, hepatitis virus seropositivity and MD used for male recipient will likely offer a good prognosis.

Extracorporeal Membrane Oxygenation Circulatory Support After Congenital Cardiac Surgery

Extracorporeal membrane oxygenation (ECMO) is widely used for circulatory support in pediatric cardiac patients with low cardiac output and hypoxemia after cardiac surgery. We evaluated retrospectively, the efficacy of postoperative ECMO support following congenital cardiac surgery in our hospital. From April 2002 to February 2008, seven patients (median age 30 months) received postoperative mechanical support. Three had complete repair including Fontan circulation and four had palliative repair. In four patients, ECMO was initiated in the operating room, in three patients in the intensive care unit, postoperatively. Of the seven patients, one died on ECMO (support withdrawn), one died shortly after ECMO was discontinued, and five were successfully weaned and survived to hospital discharge. One of the survivors died 4 months after the operation due to pneumonia and septic shock. The mean duration of ECMO support was 121 hours (in survivors). During ECMO, the major complication was bleeding, despite adequate control of activated clotting time. We conclude that ECMO support for heart failure and respiratory insufficiency after congenital cardiac surgery was effective, and the result of ECMO support for respiratory insufficiency was better than for heart failure.

Extracorporeal membrane oxygenation circulatory support after cardiac surgery

Objectives Postcardiotomy acute severe heart failure cannot be managed by medical treatment alone and most often requires some form of mechanical support. In this study we evaluate the efficacy of postoperative extracorporeal membrane oxygenation (ECMO) support following surgery for congenital heart disease (CHD) in infants and children. Methods Over a 6-year period from October 1997 to October 2003, 10 patients aged 5 days to 28.5 months (median 3 months) who underwent surgical procedures for CHD received postoperative mechanical support for failing cardiac function despite optimal medical therapy. In 3 patients ECMO was instituted in the operating room (OR) and in 7 patients this was introduced in the intensive care unit (ICU) 2 to 48 (median 20) hours postoperatively. Results Four patients (40%) were successfully weaned, while support was withdrawn in the remaining 6 due to irreversible vital organ damage. Following successful weaning, one of the survivors died 8 hours later from barotrauma and intrapulmonary hemorrhage, and anotherdied 4 months later from persistent heart failure. The other two patients remain well in NYHA class II. Conclusions Despite the adverse effects of ECMO, the methodology provided the necessary support and allowed the failing heart to recover in a number of patients where inotropic support alone proved inadequate.

Mechanical support of the pediatric cardiac patient.

Increased understanding of the anatomical nuances of congenital heart defects, improved methods of myocardial preservation, and advances in surgical techniques have led to improved results and need for postoperative mechanical support in patients undergoing congenital heart surgery. However, there remains a small portion of patients with myocardial or pulmonary failure that can can be rescued by intelligent use of mechanical support. The most widely used form of mechanical support is extracorporeal membrane oxygenation (ECMO), which has been adapted for use in congenital heart patients as well as patients with respiratory failure. Recent reports have suggested that ventricular support devices may also be useful in this patient population. A promising new application of mechanical support is for rescue during cardiac arrest; surprisingly good results have been obtained in this obviously moribund group of patients. Future developments in mechanical support include more accurate identification of patients who will benefit from this therapy and technological advances that will provide greater biocompatibility and simplification of the support circuit. Copyright 2000 by W.B. Saunders Company