Primary graft dysfunction in heart transplantation

Clinicopathological correlations in heart transplantation recipients complicated by death or re-transplantation

Purpose

This study aimed to identify and correlate pathological findings with clinical outcomes in patients after orthotopic heart transplantation (OHT) who either died or underwent a re-transplantation.

Methodology and study design

Single-center retrospective analysis of primary OHT patients who died or were re-transplanted between October 2012 and July 2021. Clinical data were matched with corresponding pathological findings from endomyocardial biopsies on antibody-mediated rejection, cellular rejection, and cardiac allograft vasculopathy. Re-assessment of available tissue samples was performed to investigate acute myocardial injury (AMI) as a distinct phenomenon. These were correlated with clinical outcomes, which included severe primary graft dysfunction. Patients were grouped according to the presence of AMI and compared.

Results

We identified 47 patients with truncated outcomes after the first OHT. The median age was 59 years, 36 patients (76%) were male, 25 patients (53%) had a prior history of cardiac operation, and 21 patients (45%) were supported with a durable assist device before OHT. Of those, AMI was identified in 22 (47%) patients (AMI group), and 25 patients had no AMI (non-AMI group). Groups were comparable in baseline and perioperative data. Histopathological observations in AMI group included a non-significant higher incidence of antibody-mediated rejection Grade 1 or higher (pAMR ≥ 1) (32% vs. 12%, P = 0.154), and non-significant lower incidence of severe acute cellular rejection (ACR ≥ 2R) (32% vs. 40%, P = 0.762). Clinical observations in the AMI group found a significantly higher occurrence of severe primary graft dysfunction (68% vs. 20%, P = 0.001) and a highly significant shorter duration from transplantation to death or re-transplantation (42 days [IQR 26, 120] vs. 1,133 days [711–1,664], P < 0.0001). Those patients had a significantly higher occurrence of cardiac-related deaths (64% vs. 24%, P = 0.020). No difference was observed in other outcomes.

Conclusion

In heart transplant recipients with a truncated postoperative course leading to either death or re-transplantation, AMI in endomyocardial biopsies was a common pathological phenomenon, which correlated with the clinical occurrence of severe primary graft dysfunction. Those patients had significantly shorter survival times and higher cardiac-related deaths. The presence of AMI suggests a truncated course after OHT.

Creatine phosphate preconditioning reduces ischemiareperfusion injury in isolated rat heart

Aim. To study the effect of simultaneous administration of creatine phosphate immediately before ischemia on cardiodynamic parameters and biomarkers of oxidative stress in the coronary venous blood flow during retrograde perfusion in an isolated rat heart.Materials and methods. 20 Wistar albino rats were divided into 2 groups: group 1 (control) and group 2 (experimental), 10 rats per group. Cannulation and retrograde perfusion of aorta of an isolated rat heart with Krebs–Henseleit buffered solution by Landendorff was performed. Both groups underwent ischemia-reperfusion injury, which included global ischemia for 20 minutes followed by reperfusion for 30 minutes. The group 2 (experimental) was preconditioned with creatine phosphate at a dose of 0.2 mmol/l for 5 min before ischemia. We registered cardiodynamic parameters and indicators of oxidative stress at the point of stabilization, at the 1st and 30th minutes of reperfusion.Results. With the impact of creatine phosphate at the 30th minute of reperfusion in the group 2 in comparison with group 1, there was found an increase in the maximum and minimum speed of pressure elevation in the left ventricle (1.7 and 1.9 times, respectively), and of systolic and diastolic pressure in the left ventricle (1.5 and 1.6 times, respectively). Biomarkers of oxidative stress (lipid peroxidation index, nitrites, superoxide anion radical and hydrogen peroxide) were also statistically significantly lower in the group 2 after the 1st minute of reperfusion (by 1.2 times, by 1.4 times, by 2.8 times and 1.9 times, respectively), and after the 30th minute (1.3 times, 2.1 times, 1.9 times and 2.1 times, respectively).Conclusion. The administration of creatine phosphate into the coronary flow 5 minutes before the onset of ischemia has a protective effect on myocardial contractility. Reduction of oxidative stress and damage can be considered as a protective effect of creatine phosphate.

The Role of Echocardiography in the Management of Heart Transplant Recipients

Transthoracic echocardiography is the primary non-invasive modality for the investigation of heart transplant recipients. It is a versatile tool that provides comprehensive information on cardiac structure and function. Echocardiography is also helpful in diagnosing primary graft dysfunction and evaluating the effectiveness of therapeutic approaches for this condition. In acute rejection, echocardiography is useful with suspected cellular or antibody-mediated rejection, with findings confirmed and quantified by endomyocardial biopsy. For identifying chronic rejection, ultrasound has a more significant role and, in some specific patients (e.g., patients with renal failure), it may offer a role comparable to coronary angiography to identify cardiac allograft vasculopathy. This review highlights the usefulness of echocardiography in evaluating normal graft function and its role in the management of heart transplant recipients.

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.

Primary Graft Dysfunction After Isolated Heart Transplantation - Incidence, Risk Factors, and Clinical Implications Based on a Single-Center Experience

BACKGROUND

Since the international consensus on primary graft dysfunction (PGD) following heart transplantation (HT) was reported in 2014, few clinical studies have been reported. We aimed to analyze the incidence, predictive factors, and clinical implications of PGD following the International Society of Heart and Lung Transplant criteria in a single center.Methods and Results:This study enrolled 570 consecutive adult patients undergoing isolated HT between November 1992 and December 2017. Under a new set of criteria, PGD-left ventricle (PGD-LV) occurred in 35 patients (6.1%; mild, n=1 [0.2%]; moderate, n=14 [2.5%]; severe, n=20 [3.5%]), whereas PGD-right ventricle (PGD-RV) occurred in 3 (0.5%). Multivariable analysis demonstrated that preoperative admission (odds ratio [OR] 4.20; 95% confidence interval [CI] 1.24-14.26; P=0.021), preoperative extracorporeal membrane oxygenation (OR 4.03; 95% CI 1.75-9.26; P=0.001), and prolonged total ischemic time (OR 1.09; 95% CI 1.02-1.15; P=0.006) were significant predictors of moderate to severe PGD-LV. Moderate to severe PGD-LV was an independent and significant risk factor for early death (OR 55.64; 95% CI 11.65-265.73; P<0.001), with its effects extending up to 3 months after HT.

CONCLUSIONS

Moderate to severe PGD-LV, as defined by the new guidelines, is an important predictor of early mortality, with effects extending up to 3 months after HT. Efforts to reduce the occurrence of moderate to severe PGD-LV may lead to better outcomes.

Acute kidney injury post-heart transplant: An analysis of peri-operative risk factors

Acute kidney injury is a common complication following heart transplantation, and the factors contributing to acute kidney injury are not well understood. We conducted a retrospective cohort study evaluating patients who underwent heart transplantation between 2009 and 2016 at a single institution. The primary endpoint was incidence of acute kidney injury as defined by Kidney Disease Improving Global Outcomes criteria. Secondary endpoints included 30-day hospital readmission, 30-day mortality, and 1-year mortality. A total of 228 heart transplant patients were included in the study for analysis. In total, 145 (64%) developed acute kidney injury, where 43 (30%) were classified as stage I, 28 (19%) as stage II, and 74 (51%) as stage III. Risk factors found to be associated with the presence of acute kidney injury included increased use of vasopressors and inotropes post-transplant. Protective factors included cardiopulmonary bypass time <170 min. Acute kidney injury was found to be associated with increased 30-day and 1-year mortality.

Incidence and impact of primary graft dysfunction in adult heart transplant recipients: A systematic review and meta-analysis

PURPOSE

Primary graft dysfunction (PGD) is a leading cause of early mortality after heart transplant (HTx). To identify PGD incidence and impact on mortality, and to elucidate risk factors for PGD, we systematically reviewed studies using the ISHLT 2014 Consensus Report definition and reporting the incidence of PGD in adult HTx recipients.

METHODS

We conducted a systematic search in January 2020 including studies reporting the incidence of PGD in adult HTx recipients. We used a random effects model to pool the incidence of PGD among HTx recipients and, for each PGD severity, the mortality rate among those who developed PGD. For prognostic factors evaluated in ≥2 studies, we used random effects meta-analyses to pool the adjusted odds ratios for development of PGD. The GRADE framework informed our certainty in the evidence.

RESULTS

Of 148 publications identified, 36 observational studies proved eligible. With moderate certainty, we observed pooled incidences of 3.5%, 6.6%, 7.7%, and 1.6% and 1-year mortality rates of 15%, 21%, 41%, and 35% for mild, moderate, severe and isolated right ventricular-PGD, respectively. Donor factors (female sex, and undersized), recipient factors (creatinine, and pre-HTx use of amiodarone, and temporary or durable mechanical support), and prolonged ischemic time proved associated with PGD post-HTx.

CONCLUSION

Our review suggests that the incidence of PGD may be low but its risk of mortality high, increasing with PGD severity. Prognostic factors, including undersized donor, recipient use of amiodarone pre-HTx and recipient creatinine may guide future studies in exploring donor and/or recipient selection and risk mitigation strategies.

Complications of left ventricular assist devices causing high urgency status on waiting list: impact on outcome after heart transplantation

Aims

Heart transplantation (HTx) represents optimal care for advanced heart failure. Left ventricular assist devices (LVADs) are often needed as a bridge‐to‐transplant (BTT) therapy to support patients during the wait for a donor organ. Prolonged support increases the risk for LVAD complications that may affect the outcome after HTx.

Methods and results

A total of 342 patients undergoing HTx after LVAD as BTT in a 10‐year period in two German high‐volume HTx centres were retrospectively analysed. While 73 patients were transplanted without LVAD complications and with regular waiting list status (T, n = 73), the remaining 269 patients were transplanted with high urgency status (HU) and further divided with regard to the observed leading LVAD complications (infection: HU1, n = 91; thrombosis: HU2, n = 32; stroke: HU3, n = 38; right heart failure: HU4, n = 41; arrhythmia: HU5, n = 23; bleeding: HU6, n = 18; device malfunction: HU7, n = 26). Postoperative hospitalization was prolonged in patients with LVAD complications. Analyses of perioperative morbidity revealed no differences regarding primary graft dysfunction, renal failure, and neurological events except postoperative infections. Short‐term survival, as well as Kaplan–Meier survival analysis, indicated comparable results between the different study groups without disadvantages for patients with LVAD complications.

Conclusions

Left ventricular assist device therapy can impair the outcome after HTx. However, the occurrence of LVAD complications may not impact on outcome after HTx. Thus, we cannot support the prioritization or discrimination of HTx candidates according to distinct mechanical circulatory support‐associated complications. Future allocation strategies have to respect that device‐related complications may define urgency but do not impact on the outcome after HTx.

Financial implications of using extracorporeal membrane oxygenation following heart transplantation

OBJECTIVES

Primary graft dysfunction after heart transplant is associated with high morbidity and mortality. Extracorporeal membrane oxygenation (ECMO) can be used to wean patients from cardiopulmonary bypass. This study retrospectively reviews a single-centre experience of post-transplant ECMO in regard to outcomes and associated costs.

METHODS

Between May 2006 and May 2019, a total of 267 adult heart transplants were performed. We compared donor and recipient variables, ECMO duration and the incidence of renal failure, bleeding, infection and cost analysis between ECMO and non-ECMO groups.

RESULTS

ECMO support was required postoperatively to manage primary graft dysfunction in 72 (27%) patients. The mean duration of ECMO support was 6 ± 3.2 days. Mean ischaemic times were similar between the groups. There was a significantly higher proportion of ventricular assist device explant to transplant in the ECMO group versus non-ECMO (38.2% vs 14.1%; P < 0.0001). ECMO patients had a longer duration of stay in the intensive care unit (P < 0.0001) and total hospital stay (P < 0.0001). Greater mortality was observed in the ECMO group (P < 0.0001). The median cost of providing ECMO was £18 000 [interquartile range (IQR): £12 750-£24 000] per patient with an additional median £35 225 (IQR: £21 487.25-£51 780.75) for ITU stay whilst on ECMO. The total median cost per patient inclusive of hospital stay, ECMO and dialysis costs was £65 737.50 (IQR: £52 566.50-£95 221.75) in the non-ECMO group compared to £145 415.71 (IQR: £102 523.21-£200 618.96) per patient in the ECMO group (P < 0.0001).

CONCLUSIONS

Patients with primary graft dysfunction following heart transplantation who require ECMO are frequently bridged to a recovery; however, the medium and longer-term survival for these patients is poorer than for patients who do not require ECMO.

Waiting list mortality and the potential of donation after circulatory death heart transplantations in the Netherlands

Background

With more patients qualifying for heart transplantation (HT) and fewer hearts being transplanted, it is vital to look for other options. To date, only organs from brain-dead donors have been used for HT in the Netherlands. We investigated waiting list mortality in all Dutch HT centres and the potential of donation after circulatory death (DCD) HT in the Netherlands.

Methods

Two different cohorts were evaluated. One cohort was defined as patients who were newly listed or were already on the waiting list for HT between January 2013 and December 2017. Follow-up continued until September 2018 and waiting list mortality was calculated. A second cohort of all DCD donors in the Netherlands (lung, liver, kidney and pancreas) between January 2013 and December 2017 was used to calculate the potential of DCD HT.

Results

Out of 395 patients on the waiting list for HT, 196 (50%) received transplants after a median waiting time of 2.6 years. In total, 15% died while on the waiting list before a suitable donor heart became available. We identified 1006 DCD donors. After applying exclusion criteria and an age limit of 50 years, 122 potential heart donors remained. This number increased to 220 when the age limit was extended to 57 years.

Conclusion

Waiting list mortality in the Netherlands is high. HT using organs from DCD donors has great potential in the Netherlands and could lead to a reduction in waiting list mortality. Cardiac screening will eventually determine the true potential.

Perioperative Low Tetraiodothyronine Levels and Adverse Outcomes After Heart Transplantation: A Retrospective, Observational Study

OBJECTIVES

Thyroid dysfunction has been shown to be associated with increased all-cause mortality and severity of chronic heart failure in critical illness and severe cardiac diseases. The present study was conducted to ascertain the relationship between perioperative free triiodothyronine and free tetraiodothyronine (fT4) levels and postoperative adverse outcomes after heart transplantation (HTX).

DESIGN

Retrospective, observational study.

SETTING

Single-center study in a quaternary care university clinical center.

PARTICIPANTS

The study comprised adult patients who underwent HTX between 2015 and 2019 and had at least 1 perioperative thyroid hormone laboratory test on the day of surgery or in the 24 hours before/after the procedure (free triiodothyronine, fT4, and thyroid-stimulating hormone).

INTERVENTIONS

No interventions were applied.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was primary graft dysfunction (PGD), defined by the consensus conference of the International Society for Heart and Lung Transplantation. A total of 151 patients were included in the final analyses. Twenty-nine (19.2%) patients had PGD. Fourteen (9.3%) patients had low fT4 levels. An independent association was found between fT4 and PGD (odds ratio 6.49; 95% confidence interval 2.26-18.61; p = 0.001), with adjusted multivariate Cox regression models.

CONCLUSION

The perioperative fT4 level could be a prognostic marker of adverse outcomes in HTX. The authors suggest appropriate perioperative monitoring of fT4 levels. Additional research is warranted to examine the optimal timing, dosage, and method of replacement.

Predicted heart mass-based size matching among recipients with moderate pulmonary hypertension: Outcomes and sex effect

BACKGROUND

There is a lack of evidence to guide appropriate donor sizing in recipients with moderate pulmonary hypertension (pHTN) awaiting heart transplantation (HTx). It is common practice to oversize donor hearts for such recipients to prevent post-operative right ventricular failure. Therefore, our objective was to determine if oversizing in pre-transplant moderate pHTN provides a survival advantage.

METHODS

The United Network for Organ Sharing database was analyzed to include HTx recipients from 1994 to 2016. Recipients were considered as having moderate pHTN if the pulmonary vascular resistance (PVR) was 2.5 to 5 Wood units (WU) or transpulmonary gradient (TPG) was 10 to 18 mm Hg. Heart size mismatch was determined using the predicted heart mass equations. A size mismatch of ≥15% in either direction was considered undersized or oversized, respectively. Ninety-day and 1-year survival were analyzed based on size matching via univariate and Cox regression analysis. Propensity matching was performed to specifically evaluate the effect of donor sex among male transplant recipients.

RESULTS

Among 29,441 HTx recipients, 10,666 had moderate pHTN by PVR criteria and 12,624 HTx patients had moderate pHTN according to TPG criteria. Among patients with a PVR of 2.5 to 5 WU, oversizing was not associated with lower mortality compared with matched hearts at 90 days (7.6% vs 7.4%; p = 0.75) and 1 year (12.1% vs 11.3%; p = 0.26). Conversely, undersizing the donor was associated with a higher 90-day (10.6% vs 7.6% vs 7.4%; p < 0.01) and 1-year (15.3% vs 12.1% vs 11.3%; p < 0.01) mortality than recipients receiving oversized or matched hearts, respectively. On Cox regression analysis, there was no benefit with oversizing at 90 days (hazard ratio [HR] 0.88; p = 0.23) and 1 year (HR 0.99; p = 0.90), whereas undersizing was associated with higher 90-day (HR 1.32; p = 0.02) and 1-year mortality (HR 1.23; p = 0.03) compared to size-matched controls. Among patients with moderate pHTN based on TPG of 10 to 18 mm Hg, neither undersizing nor oversizing was predictive of mortality at 90 days and 1 year according to Cox regression analysis. Propensity matching revealed that female-to-male transplantation had similar 1-year mortality to male-to-male transplantation, and there was no advantage to oversizing female donors for male recipients.

CONCLUSIONS

In this registry-based analysis, there was no benefit to oversizing donors for cardiac transplant recipients with moderate pHTN. Elimination of this restriction could increase the donor pool and reduce wait times for such recipients.