Prior sternotomy increases the mortality and morbidity of adult heart transplantation

Risk Estimation of Severe Primary Graft Dysfunction in Heart Transplant Recipients Using a Smartphone

Background

Currently, there are no standardized guidelines for graft allocation in heart transplants (HTxs), particularly when considering organs from marginal donors and donors after cardiocirculatory arrest. This complexity highlights the need for an effective risk analysis tool for primary graft dysfunction (PGD), a severe complication in HTx. Existing score systems for predicting PGD lack superior predictive capability and are often too complex for routine clinical use. This study sought to develop a user-friendly score integrating variables from these systems to enhance the efficacy of the organ allocation process.

Methods

Severe PGD was defined as the need for mechanical circulatory support and/or death from an unknown etiology within the first 24 hours following HTx. We used a meta-analytical approach to create a derivation cohort to identify risk factors. We then applied a logistic regression analysis to generate an equation predicting severe PGD risk. We used our previous experience in HTx to create a validation cohort. Subsequently, we implemented the formula in a smartphone application.

Results

The meta-analysis comprising six studies revealed a 10.5% ( 95% confidence interval (CI): 5.3-12.4) incidence rate of severe PGD and related 30-day mortality of 38.6%. Eleven risk factors were identified: female donors, female donor to male recipient, undersized donor, donor age, recipient on ventricular assist device support, recipient on amiodarone treatment, recipient with diabetes and renal dysfunction, re-sternotomy, graft ischemic time, and bypass time. An equation to predict the risk, including the 11 parameters (GREF-11), was created using logistic regression models and validated based on our experience involving 116 patients. In our series, 29 recipients (25%) required extracorporeal membrane oxygenation support within 24 hours post-HTx. The overall 30-day mortality was 4.3%, 3.4%, and 6.8% in the non-PGD and severe PGD groups, respectively. The area under the receiver operating characteristic (AU-ROC) curve of the model in the validation cohort was 0.804.

Conclusions

The GREF-11 application should offer HTx teams several benefits, including standardized risk assessment and bedside clinical decision support, thereby helping minimize the risk of severe PGD post-HTx.

Pericardial Closure With Expanded Polytetrafluoroethylene Patch in Left Ventricular Assist Device Surgery

To reduce adhesions after left ventricular assist device (LVAD) implantation, pericardial closure using an expanded polytetrafluoroethylene (ePTFE) patch has been suggested. However, as foreign material, ePTFE patches could increase the risk of infectious complications. In this single-center retrospective study, we investigated outcomes of pericardial closure using an ePTFE patch in LVAD implantation. We included all patients who underwent LVAD implantation at our center between 2011 and 2020 (n = 166). Primary endpoint was development of mediastinitis at any point of time between LVAD implantation and heart transplantation (HTx) or death. Secondary endpoint was overall survival. Preoperative and postoperative clinical data were collected to ensure comparability between the groups. We included 166 patients with LVAD. A total of 116 patients (70%) underwent pericardial closure using an ePTFE patch. There were significant differences between the groups in treatment setting, previous cardiac surgery, Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) level, development of driveline infection, and HTx. Patients with an ePTFE patch developed mediastinitis more frequently (16%) than patients without ePTFE patch (4%) ( p = 0.039). A significant difference in overall survival between the groups could not be confirmed ( p = 0.29). The use of PTFE patches for pericardial closure in LVAD implantation was associated with a higher incidence of mediastinitis, but not with a difference in overall survival.

Comment on Oehler et al. Outcome and Midterm Survival after Heart Transplantation Is Independent from Donor Length of Stay in the Intensive Care Unit. Life 2022, 12, 1053

Oehler et al. described an interesting finding, stating that length of stay (LOS) of the donors in the intensive care unit (ICU) did not have an impact on the outcomes and survival of recipients up to 5 years after heart transplantation (HTx) [...].

Review of Postoperative Care for Heart Transplant Recipients

The early postoperative management strategies after heart transplantation include optimizing the function of the denervated heart, correcting the causes of hemodynamic instability, and initiating and maintaining immunosuppressive therapy, allograft rejection surveillance, and prophylaxis against infections caused by immunosuppression. The course of postoperative support is influenced by the quality of allograft myocardial protection prior to implantation and reperfusion, donor-recipient heart size matching, surgical technique of orthotopic heart transplantation, and patient factors (eg, preoperative condition, immunologic compatibility, postoperative vasomotor tone, severity and reversibility of pulmonary vascular hypertension, pulmonary function, mediastinal blood loss, and end-organ perfusion). This review provides an overview of the early postoperative care of recipients and includes a brief description of the surgical techniques for orthotopic heart transplantation.

Primary Graft Dysfunction after Heart Transplantation - Unravelling the Enigma

Primary graft dysfunction (PGD) remains the main cause of early mortality following heart transplantation despite several advances in donor preservation techniques and therapeutic strategies for PGD. With that aim of establishing the aetiopathogenesis of PGD and the preferred management strategies, the new consensus definition has paved the way for multiple contemporaneous studies to be undertaken and accurately compared. This review aims to provide a broad-based understanding of the pathophysiology, clinical presentation and management of PGD.

Review of Biomechanical Studies and Finite Element Modeling of Sternal Closure Using Bio-Active Adhesives

The most common complication of median sternotomy surgery is sternum re-separation after sternal fixation, which leads to high rates of morbidity and mortality. The adhered sternal fixation technique comprises the wiring fixation technique and the use of bio-adhesives. Adhered sternal fixation techniques have not been extensively studied using finite element analysis, so mechanical testing studies and finite element analysis of sternal fixation will be presented in this review to find the optimum techniques for simulating sternal fixation with adhesives. The optimal wiring technique should enhance bone stability and limit sternal displacement. Bio-adhesives have been proposed to support sternal fixation, as wiring is prone to failure in cases of post-operative problems. The aim of this paper is to review and present the existing numerical and biomechanical sternal fixation studies by reviewing common sternal closure techniques, adhesives for sternal closure, biomechanical modeling of sternal fixation, and finite element modeling of sternal fixation systems. Investigating the physical behavior of 3D sternal fixation models by finite element analysis (FEA) will lower the expense of conducting clinical trials. This indicates that FEA studies of sternal fixation with adhesives are needed to analyze the efficiency of this sternal closure technique virtually.

Effect of novel bicaval anastomosis technique for transplantation with and without prior cardiac surgery history

Background

To evaluate the graft outcomes after orthotopic heart transplantation (HTx) with a novel bicaval anastomosis technique between recipients with and without a history of prior cardiac surgery.

Methods

Of 70 patients who underwent HTx with a novel four-corners traction bicaval anastomosis technique from August 2017 to November 2019, 60 recipients underwent the HTx procedure as their first cardiac surgery (group A), while 10 recipients underwent HTx after prior cardiac surgery (group B). Patients in the two groups were compared in terms of their preoperative baseline variables such as etiological categories, history of blood transfusion and panel reactive antibody (PRA), intraoperative operation time and blood infusion volume, postoperative treatment time, and complications such as acute rejection and 30-day mortality as well as survival rates.

Results

Preoperative variables were comparable in group A and group B except for the history of blood transfusion (0% vs. 90.0%, P<0.001, respectively); the level of PRA was 7.5%±5.8% and 9.5%±10.9% for group A and B, respectively (P=0.583), but the time of the operation was nearly 1 hour longer for group B than group A (all P<0.05). No cases of left atrial thrombosis and donor heart distortion were observed in either group. Reoperation (1.7% vs. 10.0%, P=0.267), infection (0% vs. 10.0%, P=0.142), other postoperative complications as well as the 30-day mortality (1.7% vs. 10.0%, P=0.267), and postoperative survival rates (91.5% vs. 90.0%, P=0.805) were comparable between the two groups (all P>0.05).

Conclusions

Four-corner traction bicaval anastomosis combined with a continuous everting suture technique may result in approximately comparable prognoses for heart recipients with a history of cardiac surgery when compared with those without a history of cardiac surgery and this technique may reduce the incidence of left atrial thrombosis and distortion. Further follow-up of the long-term outcomes will be required to validate these results.

Bridging With Extracorporeal Membrane Oxygenation Under the New Heart Allocation System: A United Network for Organ Sharing Database Analysis

BACKGROUND

The effect of the new donor heart allocation system on survival following bridging to transplantation with venous-arterial extracorporeal membrane oxygenation remains unknown. The new allocation system places extracorporeal membrane oxygenation-supported candidates at the highest status.

METHODS

The United Network for Organ Sharing database was queried for adults bridged to single-organ heart transplantation with extracorporeal membrane oxygenation from October 2006 to February 2020. Association between implementation of the new system and recipient survival was analyzed using Kaplan-Meier estimates, Cox proportional hazards models, and propensity score matching.

RESULTS

Of 364 recipients included, 173 and 191 were transplanted under new and old systems, respectively. Compared with the old system, waitlist time was halved under the new system (5 versus 10 days, P<0.01); recipients also demonstrated lower rates of prior cardiac surgery (32.9% versus 44.5%, P=0.03) and preoperative ventilation (30.6% versus 42.4%, P=0.02). Unadjusted 180-day survival was 90.2% (95% CI, 84.7%-94.2%) and 69.6% (95% CI, 62.6%-76.1%) under the new and old systems, respectively. Cox proportional hazards analysis demonstrated listing and transplantation under the new system to be an independent predictor of post-transplant survival (adjusted hazard ratio, 0.34 [95% CI 0.20-0.59]). Propensity score matching demonstrated a similar trend (hazard ratio, 0.36 [95% CI, 0.19-0.66]). Candidates listed under the new system were significantly less likely to experience waitlist mortality or deterioration (subhazard ratio, 0.38 [95% CI, 0.25-0.58]) and more likely to survive to transplant (subhazard ratio, 4.29 [95% CI, 3.32-5.54]).

CONCLUSIONS

Recipients transplanted following extracorporeal membrane oxygenation bridging to transplantation under the new system achieve greater 180-day survival compared with the old and demonstrate less preoperative comorbidity. Waitlist outcomes have also improved significantly under the new allocation system.

Early and long-term results of heart transplantation with reoperative sternotomy

Background

This study aims to investigate the effects of reoperative sternotomy on early and long-term outcomes after heart transplantation.

Methods

We retrospectively reviewed data of a total of 92 patients (72 males, 20 females; mean age 36 years; range, 3 to 61 years) who underwent orthotopic heart transplantation between May 1998 and July 2014. The patients were divided into three groups. Group A (n=23) included patients who underwent previous cardiac surgery with sternotomy other than ventricular assist device implantation; Group B (n=12) included patients who were bridged-to-transplant with a ventricular assist device; and Group C (n=57) included patients who for the first time underwent heart transplantation without previous sternotomy. Preoperative and operative data of the three groups were compared. The short- and long-term outcomes of all groups were analyzed.

Results

There was no significant difference among the groups, except for the age and preoperative international normalized ratio. Total ischemia time in the ventricular assist device group was longer than Group C. The length of intensive care unit stay was also longer in the ventricular assist device group than the other groups. The amount of postoperative chest tube drainage and blood transfusion was higher in Group A. Early mortality rate was significantly higher in Group A. There was no significant difference in survival among the three groups in the long-term. According to the logistic regression analysis, no variable was found to be a significant risk factor for mortality.

Conclusion

Reoperative sternotomy other than ventricular assist device implantation was found to be a risk factor for early mortality; however, mid and long-term survival rates were similar to patients in whom transplantation was the primary procedure. In patients with reoperative sternotomy, heart transplantation can be performed with similar risks to patients without resternotomy with careful selection and accurate pre- and intraoperative surgical approach.

Primary graft dysfunction after heart transplantation: a thorn amongst the roses

Primary graft dysfunction (PGD) remains the leading cause of early mortality post-heart transplantation. Despite improvements in mechanical circulatory support and critical care measures, the rate of PGD remains significant. A recent consensus statement by the International Society of Heart and Lung Transplantation (ISHLT) has formulated a definition for PGD. Five years on, we look at current concepts and future directions of PGD in the current era of transplantation.

Reoperative sternotomy is associated with primary graft dysfunction following heart transplantation

OBJECTIVES

Prior sternotomy is associated with increased morbidity and mortality following heart transplantation. However, its effect on primary graft dysfunction (PGD), a major contributor to early mortality, is unknown. Herein, this effect is studied using the International Society for Heart and Lung Transplantation consensus definition for PGD.

METHODS

Medical records of consecutive adult cardiac transplants between 2012 and 2016 were reviewed. Baseline characteristics, postoperative findings and 1-year survival were compared between patients with and without prior sternotomy.

RESULTS

Among 255 total patients included, 139 (55%) had undergone prior sternotomy; these recipients were older, more often male, had higher body mass index, higher frequencies of united network for organ sharing (UNOS) 1A status and ischaemic cardiomyopathy and experienced longer waitlist times when compared with those without prior sternotomy (all P < 0.018). Postoperatively, the prior sternotomy group exhibited higher rates of mild to severe PGD (32% vs 18%; P = 0.015) and higher short-term mortality (P = 0.017) and 1-year mortality (P = 0.047). They required more blood transfusions, had more postoperative pneumonia, wound infection and longer hospital stays. A stepwise multivariable regression model identified prior sternotomy as a predictor of PGD (odds ratio 2.7). Multiple prior sternotomies was associated with even more UNOS 1A status, ischaemic cardiomyopathy and pneumonia. However, logistic modelling did not show a difference in the rate of PGD between those with 1 or ≥2 prior sternotomies.

CONCLUSIONS

Our data suggest that prior sternotomy is a risk factor for PGD. Consistent with previous reports, prior sternotomy is associated with increased morbidity, blood product utilization and 1-year mortality following cardiac transplantation.

Cumulative Effect of Preoperative Risk Factors on Mortality After Pediatric Heart Transplantation

BACKGROUND

Risk assessment in heart transplantation is critical for candidate selection, but current models inadequately assess individual risk of postoperative mortality. We sought to identify risk factors and develop a scoring system to predict mortality after heart transplantation in children.

METHODS

The records of patients undergoing heart transplantation at our institution from 2010 through 2016 were reviewed. Clinical characteristics were recorded and compared between survivors and nonsurvivors. We used Cox proportional hazard modeling of factors associated with postoperative mortality to develop a risk factor score.

RESULTS

There were 74 patients who underwent heart transplantation at a mean age of 8.8 ± 6.6 years. Congenital heart disease was the most common indication, comprising 48.6% of the cohort. Overall mortality was 18.9%, with 10 of 14 dying within 30 days of the operation or during the initial postoperative admission (early mortality). Preoperative factors associated with overall mortality were single-ventricle congenital heart disease (hazard ratio [HR], 3.2; p = 0.042), biventricular assist device (HR, 4.8; p = 0.043), history of four or more sternotomies (HR, 3.9; p = 0.023), panel reactive antibody exceeding 10% (HR, 4.4; p = 0.013), any previous operation at another institution (HR, 3.2; p = 0.038), and pulmonary vein disease (HR, 4.7; p = 0.045). Each risk factor was assigned a point value, based on similar magnitude of the HRs. A score of 4 or higher predicted mortality with 57% sensitivity and 90% specificity.

CONCLUSIONS

In this single-center pediatric cohort, postheart transplantation mortality could be predicted using patient-specific risk factors. The cumulative effect of these risk factors predicted mortality with high specificity.

Anesthetic Management for Left Ventricular Assist Device Implantation Through Left Thoracotomy: Evaluation of On-Pump Versus Off-Pump

BACKGROUND

Ventricular assist devices (VADs) are alternative approaches to medical treatment in patients with acute or chronic heart failure. The goal of this study was to compare an anesthetic approach in patients undergoing implantation of a VAD with (on-pump) or without (off-pump) cardiopulmonary bypass (CPB) through left thoracotomy.

METHODS

A total of 32 patients were divided into 2 groups: on-pump (group 1) and off-pump (group 2). A standard anesthesia protocol was used in all patients. Baseline characteristics of the patients, intraoperative hemodynamic and respiratory variables, anesthetic agents and vasoactive drugs administered, the amount of blood products, extubation, length of hospital stay and intensive care unit stay, and postoperative complications were recorded.

RESULTS

Patients' mean age was 54.7 ± 13.3 years (range, 18-74 years). Eighteen patients underwent surgery with CPB. Demographic data of the patients, preoperative characteristics, intraoperative use of blood products, intraoperative complications, and anesthetic drugs used were similar between groups (P > .05). The duration of surgery (219 ± 23 vs 273 ± 56 minutes) and anesthesia (274 ± 38 vs 323 ± 57 minutes) were shorter in group 2; there was no difference between the 2 groups in terms of mechanical ventilation time, length of stay in the intensive care unit, and length of hospital stay. There was no decrease in postoperative oxygen parameters and an increase in patient lactate levels with the use of CPB. The use of fresh frozen plasma and platelet suspension in the postoperative period was significantly higher in group 1 (P < .05). The rate of complications and mortality rate were comparable between the 2 groups (P > .05).

CONCLUSIONS

Our study results show that the use of CPB during VAD implantation via left thoracotomy increases operation time and use of blood products, while causing no change in the rate of complications.