Long-term outcomes and clinical predictors for pacemaker-requiring bradyarrhythmias after cardiac transplantation: analysis of the UNOS/OPTN cardiac transplant database

Impact of the operative technique on mid- and long-term results following paediatric heart transplantation

AIMS

The aim of this study is to evaluate and compare the impact of the bicaval technique versus the biatrial technique (by Lower and Shumway) in paediatric heart transplant patients. Only a few studies investigate this matter regarding the long-term outcome after paediatric heart transplantation. We compared the two surgical methods regarding survival, the necessity of pacemaker implantation.

METHODS AND RESULTS

All 134 patients (aged <18 years) - (group-1) biatrial (n = 84), versus (group-2) bicaval (n = 50), who underwent heart transplantation between October 1988 and December 2021, were analysed. Freedom from events were estimated using the Kaplan-Meier method. Potential differences were analysed using the log rank test and Cox proportional hazard models. Mean ± standard deviation: Bypass time (per minutes) was higher in the group 1 as compared with group 2 (P = 0.050). Survival was not significantly different (P = 0.604) in either groups. Eighteen patients required permanent pacemaker implantation in the group 1 and only one patient required it in the group 2 (P = 0.001).

CONCLUSIONS

Paediatric heart transplantation using bicaval technique results similar long-term survival compared with the biatrial technique. The incidence of atrial rhythm disorders was significantly higher in the biatrial group, requiring a higher frequency of pacemaker implantation in this group. As a results, the bicaval technique has replaced the biatrial technique in our centre.

Pacemaker Implantation Following Heart Transplantation - Incidence and Risk Factors. Single-Center Experience

BACKGROUND

Bradyarrhythmias, requiring pacemaker (PM) implantation, are common complications following orthotopic heart transplantation (HTx). Currently used heart transplantation methods are primarily the bicaval technique and the total heart transplantation technique. The aim of the study was to assess the incidence and risk factors, including donor parameters, of conduction disorders requiring pacing after HTx.

METHODS

A population of 111 (52 ± 13 years, 91 (82%) men) heart recipients was divided into a group requiring PM implantation post-HTx and a group not requiring PM. We compared groups in terms of donor parameters, time of graft ischemia, transport and transplantation, and surgical techniques as the potential risk factors for significant bradyarrhythmias.

RESULTS

Ten of 111 patients with HTx (9%) required PM implantation. The indication in 7 cases was sinus node dysfunction (SND), in 3 patients it was complete atrioventricular block (AV-block). In the PM group, the age of 48 ± 6 vs 40 ± 11 years (P = .0227) and the body mass index (BMI) 28 ± 3 vs 26 ± 4 kg/m2 (P = .0297) of the donor were significantly higher. There was no influence of organ transport time, ischemia time, and transplantation time. All patients requiring PM implantation were transplanted using the bicaval anastomosis: 10 (100%) vs 71 (70%) in the group not requiring PM (P = .044).

CONCLUSIONS

The need for PM implantation post-HTx despite using new techniques is still common, especially in the group operated with the bicaval method. In addition, higher donor's age and BMI are risk factors of PM implantation, what is of importance as qualification criteria of donor hearts have been gradually extended.

Need for cardiac implantable electronic devices and long-term follow-up in recipients of orthotopic heart transplants

BACKGROUND

Cardiac pacemaker implantation after orthotopic heart transplantation declined dramatically after development of the bicaval anastomosis technique. However, much less is known about the rate, indications, and predictors of device implantation procedures with the current surgical technique.

OBJECTIVE

The purpose of this study was to evaluate the indications, patient characteristics, incidence, and survival related to cardiac implantable electronic device (CIED) implantation after heart transplantation.

METHODS

This was a single-center study of 399 consecutive adult recipients of orthotopic heart transplants with bicaval anastomosis from 1991 to 2017. The primary end point was freedom from pacemaker or implantable cardioverter-defibrillator (ICD) implantation, and the secondary end point was all-cause mortality.

RESULTS

At the time of transplantation, the mean age of recipients was 50 ± 12 years and that of donors 31 ± 12 years. CIEDs were implanted in 8% of recipients (n = 31): 11 pacemakers (35%) for sinus node dysfunction, 17 (55%) for high-grade heart block, and 3 ICDs (10%) for the primary prevention of sudden cardiac death. Early CIED implantation (<30 days) was rare and absent for sinus node dysfunction. The risk for CIED implantation increased progressively during follow-up (0-30 years; median 11 years), with low-, moderate-, and high-risk periods between 0 and 10, between 10 and 20, and between 20 and 30 years, respectively. Recipients receiving CIEDs survived longer after transplantation (21 years vs 13 years; P < .01). Recipients receiving pacemakers for heart block were more likely to receive older donor hearts at the time of transplantation.

CONCLUSION

The risk of pacemaker implantation increases progressively, while ICD implantation is rare. Donor age is the predominant risk factor for subsequent heart block. Early sinus node dysfunction requiring permanent pacing is rare.

Impact of prophylactic donor heart tricuspid valve annuloplasty on outcomes in heart transplantation

BACKGROUND

Tricuspid regurgitation(TR) following heart transplantation could adversely affect clinical outcomes. In an effort to reduce the incidence of TR, prophylactic donor heart tricuspid valve annuloplasty has been performed during heart transplantation in our institution. We assessed early and long-term outcomes.

METHODS

Between August 2011 and August 2021, 349 patients who underwent prophylactic tricuspid valve annuloplasty were included. Tricuspid valve annuloplasty was performed using the DeVega annuloplasty technique. The clinical outcomes of the interests included complete atrioventricular block requiring pacemaker implantation, the occurrence of significant TR(defined as moderate or greater), and survival. Long-term survival was compared in patients with and without significant TR using the Kaplan-Meier method. The Cox proportional hazards regression with time-dependent covariate analysis was used to see if significant TR affected the long-term survival.

RESULTS

There was one patient(0.3%) who required pacemaker implantation for complete atrioventricular block. No patients developed tricuspid valve stenosis that required intervention. Significant TR developed in 31 patients(8.9%) during the follow-up period. The survival rate of patients who developed significant TR was significantly lower than that of those who did not(log rank < 0.01). Significant TR was associated with the long-term mortality(HR2.92, 95%CI 1.47-5.82, p < 0.01).

CONCLUSIONS

Prophylactic donor heart tricuspid valve annuloplasty has the potential to reduce the occurrence of significant TR and can be performed safely. The significant TR that developed in patients with prophylactic annuloplasty negatively affected survival and was an independent predictor of long-term mortality.

Long-Term Outcomes of Permanent Pacemaker Implantation in Bicaval Heart Transplant Recipients

BACKGROUND

Permanent pacemakers (PPMs) may be necessary in up to 10% of patients after heart transplantation (HT).

OBJECTIVES

The purpose of this study was to evaluate long-term outcomes and clinical courses of heart transplant recipients who received PPM.

METHODS

All patients who required PPM after bicaval HT at Columbia University between January 2005 and December 2021 were included. Cases were compared to matched heart transplant recipients by age, sex, and year of transplantation. Patient and device characteristics including complications and device interrogations were reviewed. Outcomes of re-transplantation or graft failure/death were compared between groups.

RESULTS

Of 1,082 heart transplant recipients, 41 (3.8%) received PPMs. The median time from transplantation to PPM was 118 days (IQR: 18-920 days). The most common indications were sinus node dysfunction (60%, n = 25) and atrioventricular (AV) nodal disease (41.5%, n = 17). Post-implantation complications included pocket hematoma (n = 3), lead under-sensing (n = 2), and pocket infection requiring explant (n = 1). Rates of death and re-transplantation at 10 years post-HT were similar between groups. In multivariable analysis, after adjustment for mechanical circulatory support, pretransplantation amiodarone use, donor ischemic time and age, only older donor age was associated with increased risk of PPM implantation (P = 0.03). There was a significant decrease in PPM placement after 2018 (1.2% vs 4.4%, P = 0.02), largely driven by a decline in early PPM placement. There were no differences in mortality or need for re-transplantation between groups.

CONCLUSIONS

PPMs are implanted after HT for sinus and atrioventricular node dysfunctions with low incidence of device-related complications. Our study shows a decrease in PPM implantation after 2018, likely attributable to expectant management in the early postoperative period.

Extended criteria donor organ use for heart-lung transplantation in the modern era

BACKGROUND

Demand for donor hearts and lungs exceeds their supply. Extended Criteria Donor (ECD) organs are used to help meet this demand, but their impact on heart-lung transplantation outcomes is poorly characterized.

METHODS AND RESULTS

The United Network for Organ Sharing was queried for data on adult heart-lung transplantation recipients (n = 447) from 2005‒2021. Recipients were stratified based on whether they received ECD hearts and/or lungs. Morbidity was analyzed using Kruskal-Wallis, chi-square, and Fisher's exact tests. Mortality was analyzed using Kaplan-Meier estimation, log-rank tests and Cox regression. Sixty-five (14.5%) patients received two ECD organs, 134 (30.0%) received only an ECD lung, and 65 (14.5%) only an ECD heart. Recipients of two ECD organs were older, more likely to have diabetes, and more likely transplanted from 2015‒2021 (p < 0.05). Groups did not differ by pre-transplant diagnosis, intensive care unit disposition, life support use, or hemodynamics. Group five-year survival rates ranged from 54.5% to 63.2% (p = 0.428). Groups did not differ by 30-day mortality, strokes, graft rejection, or hospital length of stay.

CONCLUSIONS

Using ECD hearts and/or lungs for heart-lung transplantation is not associated with increased mortality and is a safe strategy for increasing donor organ supply in this complex patient population.

Trends, Burden, and Impact of Arrhythmias on Cardiac Transplant Recipients: A 16-year Nationwide Study

Orthotopic heart transplantation is the most effective long-term therapy for end-stage heart disease. Denervation with the loss of autonomic modulation, vasculopathy, utilization of immunosuppressant drugs, and allograft rejection may result in an increased prevalence of arrhythmias in transplanted hearts. We aim to describe the trends, distribution, and the clinical impact of arrhythmias in patients with transplanted hearts. We queried the National Inpatient Sample with administrative codes for cardiac transplant patients using procedure ICD-9-CM codes 37.5 and 33.6. Arrhythmias were extracted using validated ICD-9-CM codes. Statistical Analysis System (SAS) version 9.4 was used for analysis. There were a total of 30,020 hospitalizations of heart transplant recipients between 1999 and 2014 in the United States of which 1,6342 (54.4%) had an arrhythmia. The frequency of total arrhythmias increased from 53.6% (n=1,158) in 1999 to 67.3% (n=1,575) in 2014. Transplant patients with arrythmias was not associated with significantly higher inpatient mortality (7.72% vs 6.90%, P = 0.225). The most common arrythmia was atrial fibrillation ([AF]26.83%) followed by ventricular tachycardia (22.86%). Trends in mortality associated with arrhythmias following heart transplant has been decreasing from 12.3% in 1999 to 8.9% in 2014 (P = 0.04). Subgroup analysis of ventricular arrythmias (VA) following heart transplant were associated with increased mortality (8.61% vs 6.94%, P = 0.0229). Over half of patients develop 1 or more cardiac arrhythmia after heart transplant. There is an increasing secular trend in the frequency of arrhythmias post cardiac transplant with atrial fibrillation determined to be the most common arrhythmia.

Pacemaker Implantation following Heart Transplantation: Analysis of a Nation-Wide Database

BACKGROUND

The 2018 United-Network-for-Organ-Sharing (UNOS) allocation-system changes resulted in greater recognition of mechanical circulatory support (MCS), leading to more heart transplantations (HTx) in patients with MCS. We aimed to investigate the effect of the new UNOS allocation system on the need for a permanent pacemaker and associated complications following HTx.

METHODS

The UNOS Registry was questioned, to identify patients that received HTx in the US between 2000 and 2021. The primary objectives were to identify risk factors for the need for a pacemaker implantation following HTx.

RESULTS

49,529 HTx patients were identified, 1421 (2.9%) requiring a pacemaker post-HTx. Patients who required a pacemaker were older (53.9 ± 11.5 vs. 52.6 ± 12.8 years, p < 0.001), more frequently white (73% vs. 67%; p < 0.001) and less frequently black (18% vs. 20%; p < 0.001). In the pacemaker group, UNOS status 1A (46% vs. 41%; p < 0.001) and 1B (31% vs. 27%; p < 0.001) were more prevalent, and donor age was higher (34.4 ± 12.4 vs. 31.8 ± 11.5 years; p < 0.001). One-year survival was no different between the groups (HR: 1.08; 95% CI: 0.85, 1.37; p = 0.515). An era effect was observed (per year: OR: 0.97; 95% CI: 0.96, 0.98; p = 0.003), while ECMO pre-transplant was associated with lower risk of a pacemaker (OR: 0.41; 95% CI: 0.19, 0.86; p < 0.001).

CONCLUSIONS

While associated with various patient and transplant characteristics, pacemaker implantation does not seem to impact one-year survival after HTx. The need for pacemaker implantation was lower in the more recent era and in patients who required ECMO pre-transplant, a finding explained by recent advances in perioperative care.

Optimizing Anastomoses Technique in Orthotopic Heart Transplantation: Comparison of Biatrial, Bicaval and Modified Bicaval Technique

Implantation techniques for orthotopic heart transplantation (HTx) have evolved over the centuries. Recently new approaches of modified bicaval techniques to minimize warm ischemia are gaining popularity in the literature. Between 2010 and 2022 n = 238 patients underwent HTx in our department. The recipients were retrospectively reviewed and divided regarding their anastomoses’ technique. Anastomoses were sutured either in biatrial (n = 37), bicaval (n = 191) or in a modified bicaval (n = 10) manner with suturing of the superior cava vein and A. pulmonalis anastomosis after removing the aortic cross-clamp during the reperfusion. Warm ischemia was 62 ± 11 min for biatrial, 66 ± 15 min for bicaval, but only 48 ± 10 min for modified bicaval technique (p < 0.001). The incidence of severe primary graft dysfunction (PGD) was comparable between biatrial (27.0%) and bicaval (28.8%) anastomoses. In contrast, in patients with modified bicaval technique PGD occurred only in a single patient (10.0%). The incidence of postoperative pacemaker implantation was 18.2% for biatrial compared to 3.0% for bicaval and 0.0% for modified bicaval technique (p = 0.01). The modified bicaval technique enables to decrease the crucial warm ischemia during HTx compared to both biatrial and regular bicaval techniques. Therefore, we strongly recommend bicaval anastomoses, ideally in a modified manner.

Permanent pacing in a very long-term follow-up after orthotopic heart transplantation: A matter of when or why?

Background

Orthotopic heart transplantation (OHT) is associated with a high incidence of conduction disturbances (CD) leading to permanent pacemaker (PPM) implantation. However, the improved posttransplant survival raises the question about the pacemaker dependence (PD) in a prolonged follow‐up.

Hypothesis

The prevalence of PPM in OHT is high but not all patients are PD in a very long‐term follow‐up. Device implantation has no prognostic relevance.

Methods

We performed a retrospective analysis of patient medical records focusing on device interrogation data at the most recent follow‐up.

Results

The study population consisted of 183 patients with a mean follow‐up of 15.0 ± 6.8 years. One‐fourth of the patients had undergone PPM implantation (n = 49, 26.8%). Among these, two‐thirds were PD at last follow‐up (n = 32, 65.3%). PPM was more often in biatrial OHT and cardiac allograft vasculopathy (OR 3.0, 95% CI 1.26–7.29, p = .013 and OR 2.0, 95% CI 1.03–3.87, p = .041, respectively). Early sinus node dysfunction (SND) was the most persistent CD. PPM was associated with a poorer outcome in OHT (HR 1.9, 95% CI 1.06–3.46, p = .031) and a higher rate of fatal septicemia (HR 5.1, 95% CI 1.41–18.14, p = .013).

Conclusions

One‐fourth of the OHT recipients develop CD requiring PPM implantation, although one‐third among these are not PD in follow‐up. Early SND is associated with a higher rate of PD. PPM is associated with an inferior prognosis.

Cardiac allograft vasculopathy and donor age affecting permanent pacemaker implantation after heart transplantation

Aims

The need for permanent pacemakers (PMs) after heart transplantation (HT) is increasing. The aim was to determine the influence of cardiac allograft vasculopathy (CAV), donor age, and other risk factors on PM implantations early and late after HT and its effect on survival.

Methods and results

A retrospective, single‐centre study was performed including HTs from 1984 to July 2018. Early PM was defined as PM implantation ≤90 days and late PM as PM > 90 days. Risk factors for PM and survival after PM were determined with (time‐dependent) multivariable Cox regression. Out of 720 HTs performed, 62 were excluded (55 mortalities ≤30 days and 7 retransplantations). Of the remaining 658 patients, 95 (14%) needed a PM: 38 (6%) early and 57 (9%) late during follow‐up (median 9.3 years). Early PM risk factors were donor age [hazard ratio (HR) 1.06, P < 0.001], ischaemic time (HR 1.01, P < 0.001), and in adults amiodarone use before HT (HR 2.02, P = 0.045). Late PM risk factors were donor age (HR 1.03, P = 0.024) and CAV (HR 3.59, P < 0.001). Late PM compromised survival (HR 2.05, P < 0.001), while early PM did not (HR 0.77, P = 0.41).

Conclusions

Risk factors for early PM implantation were donor age, ischaemic time, and in adults amiodarone use before HT. Late PM implantation risk factors were donor age and CAV. Late PM diminished survival, which is probably a surrogate marker for underlying progressive cardiac disease.

Trends, Prevalence, and Outcomes of Sudden Cardiac Arrest Post Cardiac Transplant: A Nationwide 16-Year Study

Heart transplantation is the most effective long-term therapy for end-stage heart disease. There is limited data related to sudden cardiac arrest (SCA) in postheart transplant recipients. We aimed to describe the trends, and rate of SCA following heart transplantation and thereby identify clinical predictors as well as outcomes of SCA in patients post-transplant. We queried the National Inpatient Sample (NIS) with administrative codes for SCA and heart transplant. We assessed baseline differences between SCA and non-SCA admissions, with hazard ratios adjusted for age, gender, CCI, and race. Multivariable logistic regression models were generated to identify the independent predictors for SCA. There was a total of 30,020 hospitalizations of heart transplant recipients between 1999 and 2014 in the United States and among these 1,953 patients (6.5%) suffered SCA with an increasing trend of admissions for SCA. Among the patients who suffered from SCA, 18.83% died during the same hospitalization, 19.29% were discharged to a long-term facility, and 61.38% were discharged home. Multivariate analysis demonstrated that conduction system disorders (Hazard ratio [95% confidence interval]; 7.1 [4.5-11.1]), female gender (HR:1.2 [1.1-1.3]), diabetes (HR:1.4 [1.2-1.6]), and hypertension (HR:1.2 [1.1-1.4]) were the strongest predictors for SCA. SCA hospitalizations occur in 6.5% of patients post cardiac transplant and have been increasing from 1999 to 2014. Conduction block, graft rejection, female gender, hypertension, diabetes are independent predictors for SCA in heart transplant recipients.

A Meta-Analysis on Prophylactic Donor Heart Tricuspid Annuloplasty in Orthotopic Heart Transplantation: High Hopes from a Small Intervention

(1) Background: Tricuspid regurgitation (TR) is the most frequent valvulopathy in heart transplant recipients (HTX). We aimed to assess the influence of prophylactic donor heart tricuspid annuloplasty (TA) in orthotopic HTX (HTX-A), comparing the outcomes with those of HTX patients. (2) Methods: Electronic databases of PubMed, EMBASE, and SCOPUS were searched. The endpoints were as follows: the overall rate of postprocedural TR (immediate, one week, six months, and one year after the procedure), postoperative complications (permanent pacemaker implantation rate, bleeding), redo surgery for TR, and mortality. (3) Results: This meta-analysis included seven studies. Immediate postprocedural, one-week, six-month and one-year tricuspid insufficiency rates were significantly lower in the HTX-A group. There was no difference in permanent pacemaker implantation rate between the groups. The incidence of postoperative bleeding was similar in both arms. The rate of redo surgery for severe TR was reported only by two authors. In both publications, the total number of events was higher in the HTX cohort, meanwhile pooled effect analysis showed no difference among the intervention and control groups. Mortality at one year was similar in both arms. (4) Conclusion: Our study showed that donor heart TA reduces TR incidence in the first year after orthotopic heart transplantation without increasing the surgical complexity. This is a potentially important issue, given the demand for heart transplants and the need to optimize outcomes when this resource is scarce.

Management of Arrhythmias After Heart Transplant: Current State and Considerations for Future Research

Orthotropic heart transplantation remains the most effective therapy for patients with end-stage heart failure, with a median survival of ≈13 years. Yet, a number of complications are observed after orthotropic heart transplantation, including atrial and ventricular arrhythmias. Several factors contribute to arrhythmias, such as autonomic denervation, effect of the surgical technique, acute and chronic rejection, and transplant vasculopathy among others. To minimize risk of future arrhythmias, the bicaval technique and minimizing ischemic time are current surgical standards. Sinus node dysfunction is the most common indication for early (within 30 days) pacemaker implantation, whereas atrioventricular block incidence increases as time from transplant increases. Atrial fibrillation can occur in the first few weeks following transplantation but is uncommon in the long term unless secondary to a precipitant such as acute rejection. The most common atrial arrhythmias are atrial flutters, which are mainly typical, but atypical circuits can be observed such as those that involve the remnant donor atrium in regions immediately adjacent to the atrioatrial anastomosis suture line. Choosing the appropriate pharmacological therapy requires careful consideration due to the potential interaction with immunosuppressive agents. Despite historical concerns, adenosine is effective and safe at reduced doses if administered under cardiac monitoring. Catheter ablation has emerged as an effective treatment strategy for symptomatic supraventricular tachycardias, including ablation of atypical flutter circuits. Cardiac allograft vasculopathy is an important risk factor for sudden cardiac death, yet the role of prophylactic implantable cardioverter-defibrillator implant for sudden death prevention is unclear. Current indications for implantable cardioverter-defibrillator implantation are as in the nontransplant population. A number of questions for future research are posed.

Cardiac Implantable Electronic Devices Following Heart Transplantation

Permanent pacemaker (PPM) implantation is required in a subset of patients (∼10%) for sinus node dysfunction or atrioventricular block both early and late after heart transplantation. The incidence of PPM implantation has decreased to <5% with the advent of bicaval anastamosis transplantation surgery. Pacing dependence upon follow-up has been variably reported. An even smaller percentage of transplantation recipients (1.5% to 3.4%) undergo implantable cardioverter-defibrillator (ICD) placement. Rigorous data are lacking for the use of ICDs in the transplantation population and is largely derived from cohort studies and case series. Sudden cardiac death occurs in approximately 10% of transplantation recipients, but multiple nonarrhythmic factors are believed to be responsible, including acute rejection, late graft failure with electromechanical dissociation, and ischemia due to cardiac allograft vasculopathy. This review provides a comprehensive analysis of the existing data regarding the role for PPMs and ICDs in this population, including leadless PPMs and subcutaneous ICDs, special considerations, and future directions.

Bicaval vs biatrial anastomosis techniques in orthotopic heart transplantation: An updated analysis of the UNOS database

BACKGROUND

Despite the significant increase in the number of orthotopic heart transplants (OHT) performed yearly using the bicaval anastomosis technique, the impact on long-term outcomes remains a topic of debate. We analyzed the United Network for Organ Sharing (UNOS) database in search of the latest insight.

METHODS

We performed a retrospective analysis of the UNOS database from 2006 to 2016 to identify first-time OHT recipients. Patients were primarily stratified according to anastomosis technique: bicaval vs biatrial. Baseline characteristics and clinical status were recorded. The primary endpoint was all-cause mortality. Secondary outcomes included need for permanent pacemaker (PPM), and length of hospital stay (LOS). The Kaplan-Meier method was used to compare survival between the two groups. The Cox proportional hazards regression model was used to conduct multivariable analysis. Statistical significance established at P < .0001.

RESULTS

A total of 26 990 patients were identified. Of those who met the inclusion criteria (21 597), 16 573 (77%) underwent bicaval anastomosis. There were no major differences in baseline characteristics between the two groups. The bicaval anastomosis technique was not associated with increased survival during the study period (hazard ratio: 0.97; P = .3557), but the bicaval group required postoperative PPM less often (2.51% vs 5.79%, P < .0001) and was associated with shorter LOS on multivariable analysis.

CONCLUSIONS

The use of either bicaval or biatrial anastomosis during OHT offers comparable survival advantage. Nonetheless, bicaval anastomosis is associated with less need for postoperative PPM and slightly shorter LOS.

Clinical and procedural characteristics predicting need for chronotropic support and permanent pacing post-heart transplantation

BACKGROUND

Postoperative bradycardia can complicate orthotopic heart transplantation (OHT). Previous studies suggested donor age and surgical technique as possible risk factors. However, risk factors in the era of bicaval anastomosis have not been elucidated.

OBJECTIVE

We sought to examine the association between donor/recipient characteristics with need for chronotropic support and permanent pacemaker (PPM) implantation in patients with OHT.

METHODS

All patients treated with OHT between January 2003 and January 2018 at the Hospital of the University of Pennsylvania were retrospectively evaluated until June 2018. Chronotropic support was given upon postoperative inability to increase the heart rate to patient's demands and included disproportionate bradycardia and junctional rhythm.

RESULTS

A total of 820 patients (mean age 51.3 ± 12.6 years; 607, 74% men) underwent 826 OHT procedures (787 patients, 95.3% bicaval anastomosis). Patients who were exposed to amiodarone (odds ratio [OR] 2.30; 95% confidence interval [CI] 1.58-3.34; P < .001) and have older donor (OR 1.02; 95% CI 1.01-1.04; P = .001) were more likely to develop need for chronotropic support. In multivariable analysis, recipient age (OR 1.03; 95% CI 1.00-1.06; P = .04) and biatrial anastomosis (OR 6.12; 95% CI 2.48-15.09) were significantly associated with PPM implantation within 6 months of OHT. No association was found between pre-OHT amiodarone use and PPM implantation. No risk factors assessed were associated with PPM implantation 6 months post-OHT.

CONCLUSION

Surgical technique and donor age were the main risk factors for the need for chronotropic support post-OHT, whereas surgical technique and recipient age were risk factors for early PPM implantation.

Risk factors and survival of patients with permanent pacemaker implantation after heart transplantation

Background

Permanent pacemaker (PPM) implantation after heart transplantation (HTX) may be required due to severe bradycardia. The aim of this study was to investigate the risk factors, indications, perioperative outcomes and complications of PPM implantation after HTX as well as the underlying effect on post-transplant mortality including causes of death.

Methods

This registry study included 621 patients receiving HTX at Heidelberg Heart Center between 1989 and 2018. Patients were stratified by PPM implantation after HTX. Data analysis of risk factors for PPM implantation included donor and recipient demographics, post-transplant medication, mortality, and causes of death.

Results

Thirty-six patients (5.8%) received PPM implantation after HTX, 12 (33.3%) with early PPM and 24 (66.7%) with late PPM. Indications for PPM implantation after HTX included sinus node dysfunction (SND) (n=15; 41.7%) and atrioventricular block (AVB) (n=21; 58.3%). Multivariate analysis revealed recipient body mass index (BMI) [hazard ratio (HR): 1.10; confidence interval (CI): 1.01-1.21; P=0.03], donor age (HR: 1.07; CI: 1.03-1.10; P<0.01), and biatrial HTX (HR: 2.63; CI: 1.22-5.68; P=0.01) as significant risk factors for PPM implantation after HTX. Kaplan-Meier estimator displayed a statistically significant inferior 5-year post-transplant survival among patients with early PPM after HTX in comparison to patients with late PPM or no PPM after HTX (P<0.01) along with a higher percentage of death due to infection (P<0.01).

Conclusions

Multivariate risk factors for PPM implantation after HTX include recipient BMI, donor age, and biatrial HTX. Early PPM implantation after HTX is associated with increased 5-year post-transplant mortality due to infection.

Controversies in the Postoperative Management of the Critically Ill Heart Transplant Patient

Heart transplant recipients are susceptible to a number of complications in the immediate postoperative period. Despite advances in surgical techniques, mechanical circulatory support (MCS), and immunosuppression, evidence supporting optimal management strategies of the critically ill transplant patient is lacking on many fronts. This review identifies some of these controversies with the aim of stimulating further discussion and development into these gray areas.

Transvenous Extraction and Removal of Pacing Leads Placed after Cardiac Transplantation

There is an increasing prevalence of cardiac implantable electronic devices (CIEDs) due to expanding adoption and availability of these evidence-based therapies. With the increased prevalence of these life-saving devices, there has also been an increased demand for lead removal and lead extraction. Understanding the specific subgroups of patients at high risk for complications during and after lead extraction has become imperative to properly manage endovascular CIED leads. There have been multiple published studies describing clinical variables that predict adverse outcomes in CIED system extractions; however, the risk of complications in leads placed after cardiac transplantation has not specifically been addressed to date. We present four cases of transvenous extraction and removal of pacing leads placed after cardiac transplantation. There were no major complications related to extraction in these four cases; however, three of the four patients died within one year after the procedure. While the etiology of death in these cases seemed to be unrelated to the extraction procedure, the indications for extraction (infection in the setting of immunosuppression and calcineurin-associated ESRD and poor sensing/capture possibly secondary to chronic rejection and/or frequent right heart biopsies) likely contributed at least indirectly to the subsequent death.

The Rogue P-wave: Atrial Dissociation Following Bicaval Heart Transplantation

We report the first case, to our knowledge, of atrial dissociation in a patient who underwent bicaval orthotopic heart transplantation. It was believed that atrioventricular dissociation prompting pacemaker implantation likely represented donor sinus bradycardia/arrest with intact atrioventricular conduction with surgically isolated recipient atrial activity.

Fatal cardiac arrest in pediatric heart transplant recipients: Query of the UNOS database

The incidence of death by CA after PHTx is unknown. We aimed to determine the incidence and factors for fatal CA after PHTx, and whether a PM affects survival. Retrospective cohort study utilizing the United Network of Organ Sharing registry of patients transplanted ≤18 years. Multivariable analyses in hazard-function domain and Kaplan-Meier analyses were performed for an outcome of death due to CA. There were 7719 PHTx patients queried. CA was the reported cause of death in 11%. Age ≥13 years at time of transplant, presence of a PM, and depressed EF were identified as significant factors for fatal CA. Death due to CA beyond 10 years post-transplant was associated with depressed EF, CAV, and presence of a PM. Kaplan-Meier analysis demonstrated higher likelihood of fatal CA in patients with CAV and in those with a PM vs those without. In total, 15% of patients with a PM died from CA. CA is a relatively common cause of death after PHTx. The benefit of a PM remains unclear, but its presence does not confer complete protection. Patients with associated factors warrant vigilant surveillance and consideration for retransplantation.

Anesthetic Considerations in Transplant Recipients for Nontransplant Surgery

As solid organ transplantation increases and patient survival improves, it will become more common for these patients to present for nontransplant surgery. Recipients may present with medical problems unique to the transplant, and important considerations are necessary to keep the transplanted organ functioning. A comprehensive preoperative examination with specific focus on graft functioning is required, and the anesthesiologist needs pay close attention to considerations of immunosuppressive regimens, blood product administration, and the risk benefits of invasive monitoring in these immunosuppressed patients. This article reviews the posttransplant physiology and anesthetic considerations for patients after solid organ transplantation.

Postoperative management of heart transplantation patients

Heart transplant recipients are at risk for a number of post-transplantation complications such as graft dysfunction, rejection, and infection. The rates of many complications are decreasing over time, and prognosis is improving. However, these patients continue to experience significant morbidity and mortality. This review focuses on the optimal management of heart transplant recipients in the postoperative period, based on current knowledge. More information is needed about the best ways to predict, prevent, and treat primary graft dysfunction, right ventricular failure, and cellular and antibody-mediated rejection.

Pacemaker Use Following Heart Transplantation

BACKGROUND

The incidence of permanent pacemaker implantation after orthotopic heart transplantation has been reported to be 2%-24%. Transplanted hearts usually exhibit sinus rhythm in the operating room following reperfusion, and most patients do not exhibit significant arrhythmias during the postoperative period. However, among the patients who do exhibit abnormalities, pacemakers may be implanted for early sinus node dysfunction but are rarely used after 6 months. Permanent pacing is often required for atrioventricular block. A different cohort of transplant patients presents later with bradycardia requiring pacemaker implantation, reported to occur in approximately 1.5% of patients. The objectives of this study were to investigate the indications for pacemaker implantation, compare the need for pacemakers following bicaval vs biatrial anastomosis, and examine the long-term outcomes of heart transplant patients who received pacemakers.

METHODS

For this retrospective, case-cohort, single-institution study, patients were identified from clinical research and administrative transplant databases. Information was supplemented with review of the medical records. Standard statistical techniques were used, with chi-square testing for categorical variables and the 2-tailed t test for continuous variables. Survival was compared with the use of log-rank methods.

RESULTS

Between January 1968 and February 2008, 1,450 heart transplants were performed at Stanford University. Eighty-four patients (5.8%) were identified as having had a pacemaker implanted. Of these patients, 65.5% (55) had the device implanted within 30 days of transplantation, and 34.5% (29) had late implantation. The mean survival of patients who had an early pacemaker implant was 6.4 years compared to 7.7 years for those with a late pacemaker implant (P<0.05). Sinus node dysfunction and heart block were the most common indications for pacemaker implantation. Starting in 1997, a bicaval technique was used for implantation. The incidence of pacemaker implantation by technique was 2.0% for bicaval and 9.1% for biatrial (P=0.001). Significantly more rejection episodes occurred in the pacemaker group (2.67 ± 2.18) compared with the no-pacemaker group (2.01 ± 2.05) (P<0.05).

CONCLUSION

Our results show a decreased pacemaker need after bicaval anastomosis and that more patients who needed a pacemaker after transplantation had a pretransplant diagnosis of ischemic cardiomyopathy. In our cohort, the need for a permanent pacemaker was also associated with older donor grafts and an increase in the number of treated rejection episodes.

Accelerated graft dysfunction in heart transplant patients with persistent atrioventricular conduction block

AIMS

Bradyarrhythmia following heart transplantation is common-∼7.5-24% of patients require permanent pacemaker (PPM) implantation. While overall mortality is similar to their non-paced counterparts, the effects of chronic right ventricular pacing (CRVP) in heart transplant patients have not been studied. We aim to examine the effects of CRVP on heart failure and mortality in heart transplant patients.

METHODS AND RESULTS

Records of heart transplant recipients requiring PPM at St Vincent's Hospital, Sydney, Australia between January 1990 and January 2015 were examined. Patient's without a right ventricular (RV) pacing lead or a follow-up time of <1 year were excluded. Patients with pre-existing abnormal left ventricular function (<50%) were analysed separately. Patients were grouped by pacing dependence (100% pacing dependent vs. non-pacing dependent). The primary endpoint was clinical or echocardiographic heart failure (<35%) in the first 5 years post-PPM. Thirty-three of 709 heart transplant recipients were studied. Two patients had complete RV pacing dependence, and the remaining 31 patients had varying degrees of pacing requirement, with an underlying ventricular escape rhythm. The primary endpoint occurred significantly more in the pacing-dependent group; 2 (100%) compared with 2 (6%) of the non pacing dependent group (P < 0.0001 by log-rank analysis, HR = 24.58). Non-pacing-dependent patients had reversible causes for heart failure, unrelated to pacing. In comparison, there was no other cause of heart failure in the pacing-dependent group.

CONCLUSIONS

Permanent atrioventricular block is rare in the heart transplant population. We have demonstrated CRVP as a potential cause of accelerated graft failure in pacing-dependent heart transplant patients.

Arrhythmias in the Heart Transplant Patient

Orthotopic heart transplantation (OHT) is currently the most effective long-term therapy for patients with end-stage cardiac disease, even as left ventricular devices show markedly improved outcomes. As surgical techniques and immunosuppressive regimens have been refined, short-term mortality caused by sepsis has decreased, while morbidity caused by repeated rejection episodes and vasculopathy has increased, and is often manifested by arrhythmias. These chronic transplant complications require early and aggressive multidisciplinary treatment. Understanding the relationship between arrhythmias and these complications in the acute and chronic stages following OHT is critical in improving patient prognosis, as arrhythmias may be the earliest or sole presentation. Finally, decentralised/ denervated hearts represent a unique opportunity to investigate the underlying mechanisms of arrhythmias.

The impact of mean first-year heart rate on outcomes after heart transplantation: does it make a difference?

BACKGROUND

Cardiac denervation following transplantation has a variable effect on heart rate (HR), and the consequence of this is not known. We examined the impact of first-year HR on five-yr outcomes after heart transplant.

METHODS

We evaluated 544 heart transplant recipients from 1994 to 2008. Patients were divided into groups by mean first-year HR: group 1, HR < 90 (mean 85.0 ± 4.3); group 2, 90 ≤ HR < 110 (mean 97.8 ± 4.9); group 3, HR ≥ 110 (mean 111.5 ± 1.8). Endpoints included one-yr freedom from treated rejection, five-yr survival, five-yr freedom from cardiac allograft vasculopathy (CAV), and five-yr freedom from non-fatal major adverse cardiac events (NF-MACE).

RESULTS

One-yr freedom from treated rejection, five-yr survival and freedom from CAV were not significantly different between groups. Five-yr freedom from NF-MACE was significantly lower in group 3 compared with group 2, 69% vs. 91%, p < 0.01, mainly due to higher prevalence of congestive heart failure (CHF) in group 3 over five yr.

CONCLUSIONS

Mean first-year HR does not provide prognostic significance for one-yr freedom from treated rejection, five-yr survival or development of CAV five yr after heart transplant. These results suggest that HR post-heart transplantation does not affect long-term outcomes, but high first-year HRs may be associated with new-onset CHF.

Heart rate after cardiac transplantation-lessons from the tortoise and the shrew

There is a striking consistency in the total number of heart beats accrued over a lifetime across a range of animal species despite vast differences in size. Moreover, an inverse relationship is observed between heart rate and lifespan, leading to speculation that elevated heart rate could significantly affect longevity. It is the aim of this review to analyze heart rate as a contributing factor in defining the functional lifespan of the transplanted human heart, which may unavoidably determine the longevity of the recipient. Sinus tachycardia occurs as a result of sympathetic/parasympathetic denervation, an unavoidable consequence of transplantation. The effect of elevated heart rate in this cohort has been scarcely reported. We highlight herein multitudinous mechanisms whereby elevated heart rate accelerates the deterioration in cardiac function and arterial elasticity due to injury and stress accumulation. Additionally, we propose a significant role for heart rate in confounding the alloimmune response. Tachycardia exacerbates injurious episodes of myocardial ischemia and significantly increases the production of reactive oxygen species via increased metabolism. These factors promote immune infiltration and activation, contributing to acute and chronic rejection. Further research is required to assess the potential therapeutic benefits of heart rate reduction.