Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

A Review of Biomarkers of Cardiac Allograft Rejection: Toward an Integrated Diagnosis of Rejection

Despite major advances in immunosuppression, allograft rejection remains an important complication after heart transplantation, and it is associated with increased morbidity and mortality. The gold standard invasive strategy to monitor and diagnose cardiac allograft rejection, based on the pathologic evaluation of endomyocardial biopsies, suffers from many limitations including the low prevalence of rejection, sample bias, high inter-observer variability, and international working formulations based on arbitrary cut-offs that simplify the landscape of rejection. The development of innovative diagnostic and prognostic strategies—integrating conventional histology, molecular profiling of allograft biopsy, and the discovery of new tissue or circulating biomarkers—is one of the major challenges of translational medicine in solid organ transplantation, and particularly in heart transplantation. Major advances in the field of biomarkers of rejection have paved the way for a paradigm shift in the monitoring and diagnosis of cardiac allograft rejection. We review the recent developments in the field, including non-invasive biomarkers to minimize the number of protocol endomyocardial biopsies and tissue biomarkers as companion tools of pathology to refine the diagnosis of cardiac rejection. Finally, we discuss the potential role of these biomarkers to provide an integrated bio-histomolecular diagnosis of cardiac allograft rejection.

Favorable Outcome of an Exclusively Posttransplant Prophylactic Strategy After Heart Transplantation in Recipients With High Immunological Risk

BACKGROUND

Management of the increasing number of sensitized heart transplant candidates has become a recurrent issue. Rather than using pretransplant desensitization therapies, we used a posttransplant prophylactic strategy. Our aim was to describe outcomes in transplant recipients with preformed donor-specific anti-HLA antibodies (pfDSA) managed with this strategy.

METHODS

A posttransplant protocol was applied to patients transplanted with pfDSA, consisting of perioperative management of DSA (polyvalent immunoglobulins +/- perioperative plasmapheresis sessions, according to DSA level, as well as induction therapy) and systematic treatment of subsequent antibody-mediated rejection (AMR), even when subclinical. We performed a retrospective analysis of this prospective protocol. The study included all consecutive first recipients of a noncombined heart transplant performed between 2009 and 2015 at our center. The primary endpoint was all-cause mortality. Secondary endpoints included primary graft dysfunction, early posttransplant bleeding, rejection, and cardiac allograft vasculopathy-free survival.

RESULTS

A total of 523 patients were studied, including 88 (17%) and 194 (37%) transplanted with DSA mean fluorescence intensity (MFI) of 500 to 1000 and greater than 1000, respectively. The median follow-up period was 4.06 years. Survival was not significantly different between groups. Rejection-free survival was worse in patients with pfDSA MFI >1000, evidenced by a fourfold increase in the risk of antibody-mediated rejection. The incidence of primary graft dysfunction and cardiac allograft vasculopathy-free survival did not significantly differ between groups. Perioperative plasmapheresis increased the risk for transfusion of packed red blood cells.

CONCLUSIONS

This exclusively posttransplant prophylactic strategy achieved favorable outcomes in heart transplant recipients with pfDSA.

Predictive risk factors for postoperative pneumonia after heart transplantation

Background

Pneumonia is a frequent complication in patients undergoing heart transplantation (HTx) that increases morbidity and mortality in this population. Nevertheless, the risk factors for postoperative pneumonia (POP) are still unknown. The aim of this study was to investigate the predictive risk factors for POP in HTx recipients.

Methods

In this retrospective study, all patients undergoing HTx between January 2014 and December 2015 were included. All cases of POP occurring until hospital discharge were investigated. The study aimed to determine risk factors using univariate and multivariate Cox regression models. Data are expressed in Odds Ratio [95% CI]. P < 0.05 was necessary to reject the null hypothesis.

Results

A total of 175 patients were included without any patients being lost to follow-up, and 89 instances of POP were diagnosed in 59 (34%) patients. Enterobacteriaceae and Pseudomonas aeruginosa were the most common pathogens. In the multivariate analysis, the risk factors were preoperative mechanical ventilation (OR 1.42 [1.12–1.80], P < 0.01) and perioperative blood transfusion (OR 1.42 [95% CI: 1.20–1.70], P < 0.01). POP significantly impacted mortality at 30 days (OR: 4 [1.3–12.4], P = 0.01) and 1 year (OR: 6.8 [2.5–8.4], P < 0.01) and was associated with a longer duration of mechanical ventilation, time to weaning from venoarterial extracorporeal membrane oxygenation and stay in an intensive care unit. Plasma exchanges and intravenous administration of immunoglobulins did not increase the risk of POP.

Conclusion

After HTx, preoperative mechanical ventilation and blood transfusion were risk factors for POP and were associated with increased mortality. Enterobacteriaceae and Pseudomonas aeruginosa are the most common pathogens of POP.

When to intervene for donor-specific antibody after heart transplantation

PURPOSE OF REVIEW

Posttransplant donor-specific human leukocyte antigen (HLA) antibodies (DSA) represent a complex area in heart transplantation with nonstandardized practice and paucity of clinical data to guide optimal management.

RECENT FINDINGS

De novo DSA after heart transplantation is common and associated with rejection, cardiac allograft vasculopathy, allograft failure, and mortality. Advances in methods for HLA antibody detection have enabled identification of DSA with high precision and sensitivity. The detection of HLA antibodies must, however, be interpreted within appropriate laboratory and clinical contexts; it remains unclear which DSA are associated with greatest clinical risk. Increased antibody and clinical surveillance as well as optimization of maintenance immunosuppression are required for all patients with DSA. Antibody-directed therapies are reserved for patients with allograft dysfunction or rejection. Treatment of DSA may also be considered in asymptomatic high-risk patients including those in whom DSA arise de novo posttransplant, is persistent, high titer, or complement activating. The impact of DSA reduction and removal on long-term clinical outcomes remains unknown.

SUMMARY

Despite improvements in DSA detection, identification, and characterization, best therapeutic strategies are unclear. Prospective multicenter studies are needed to develop effective standardized approaches for DSA management in heart transplantation.