Impact of pre-diabetes on heart transplant outcomes in patients with advanced heart failure

Pre-transplant Type 2 Diabetes Mellitus Is Associated With Higher Graft Failure and Increased 5-Year Mortality After Heart Transplantation

Aims

Cardiac transplant recipients often suffer from type 2 diabetes mellitus (T2DM) but its influence on graft failure and post-transplant mortality remains unknown. The aim of this study was to investigate the long-term effects of pre-transplant T2DM in patients after heart transplantation (HTX).

Methods

This study included a total of 376 adult patients who received HTX at Heidelberg Heart Center between 01/01/2000 and 01/10/2016. HTX recipients were stratified by diagnosis of T2DM at the time of HTX. Patients with T2DM were further subdivided by hemoglobin A1c (HbA1c ≥ 7.0%). Analysis included donor and recipient data, immunosuppressive drugs, concomitant medications, post-transplant mortality, and causes of death. Five-year post-transplant mortality was further assessed by multivariate analysis (Cox regression) and Kaplan–Meier estimator.

Results

About one-third of all HTX recipients had T2DM (121 of 376 [32.2%]). Patients with T2DM showed an increased 5-year post-transplant mortality (41.3% versus 29.8%; P = 0.027) and had a higher percentage of death due to graft failure (14.9% versus 7.8%; P = 0.035). Multivariate analysis showed T2DM (HR: 1.563; 95% CI: 1.053–2.319; P = 0.027) as an independent risk factor for 5-year mortality after HTX. Kaplan–Meier analysis showed a significantly better 5-year post-transplant survival of patients with T2DM and a HbA1c < 7.0% than patients with T2DM and a HbA1c ≥ 7.0% (68.7% versus 46.3%; P = 0.008) emphasizing the clinical relevance of a well-controlled T2DM in HTX recipients.

Conclusion

Pre-transplant T2DM is associated with higher graft failure and increased 5-year mortality after HTX.

Oral Glucose Tolerance Test for the Screening of Glucose Intolerance Long Term Post-Heart Transplantation

Post-transplant diabetes mellitus (PTDM) is a frequent complication post-heart transplantation (HT), however long-term prevalence studies are missing. The aim of this study was to determine the prevalence and determinants of PTDM as well as prediabetes long-term post-HT using oral glucose tolerance tests (OGTT). Also, the additional value of OGTT compared to fasting glucose and glycated hemoglobin (HbA1c) was investigated. All patients > 1 year post-HT seen at the outpatient clinic between August 2018 and April 2021 were screened with an OGTT. Patients with known diabetes, an active infection/rejection/malignancy or patients unwilling or unable to undergo OGTT were excluded. In total, 263 patients were screened, 108 were excluded. The included 155 patients had a median age of 54.3 [42.2–64.3] years, and 63 (41%) were female. Median time since HT was 8.5 [4.8–14.5] years. Overall, 51 (33%) had a normal range, 85 (55%) had a prediabetes range and 19 (12%) had a PTDM range test. OGTT identified prediabetes and PTDM in more patients (18% and 50%, respectively), than fasting glucose levels and HbA1c. Age at HT (OR 1.03 (1.00–1.06), p = 0.044) was a significant determinant of an abnormal OGTT. Prediabetes as well as PTDM are frequently seen long-term post-HT. OGTT is the preferred screening method.

Evaluation of a Heart Transplant Candidate

PURPOSE OF REVIEW

Heart transplantation is the best option for irreversible and critically advanced heart failure. However, limited donor pool, the risk of rejection, infection, and right ventricular dysfunction in short-term post-transplant period, as well as, the development of coronary allograft vasculopathy and malignancy in the long-term post-transplant period limits the utility of heart transplantation for all comers with advanced heart failure. Therefore, selection of appropriate candidates is very important for the best short and long-term prognosis. In this article, we discuss the principles of selection of candidates and compare to the recently updated International Society for Heart and Lung Transplantation (ISHLT) listing criteria with the goal of updating current clinical practice.

RECENT FINDINGS

We found that while most of the recommendations in the new listing criteria are continuous with the previous criteria, updated recommendations are made on the risk stratification models in choosing transplantation candidates. Recommendation on hepatic dysfunction is not directly included in the updated ISHLT listing criteria; however, adoption of the Model for End-stage Liver Disease (MELD) score and modified MELD scores in the evaluation of risk are suggested in recent studies. In conclusion, evaluation of patient selection for heart transplantation should be comprehensive and individualized with respect to indications and the risk of comorbidities of candidates. With the advancement of mechanical circulatory support (MCS), the selection of heart transplantation candidate is continuously evolving and widened. MCS as bridge to candidacy should be considered when the candidate has potentially reversible risk factors for transplantation.