Neurologic aspects of heart transplantation

Heart Transplantation-Postoperative Considerations

Heart transplantation (HT) remains the best treatment of patients with severe heart failure who are deemed to be transplant candidates. The authors discuss postoperative management of the HT recipient by system, emphasizing areas where care might differ from other cardiac surgery patients. Working together, critical care physicians, heart transplant surgeons and cardiologists, advanced practice providers, pharmacists, transplant coordinators, nursing staff, physical therapists, occupational therapists, rehabilitation specialists, nutritionists, health psychologists, social workers, and the patient and their loved ones partner to increase the likelihood of a successful outcome.

Intracerebral opportunistic infections caused by immunosuppressants after orthotopic liver transplantation: Report of two cases and literature review

Central nervous system (CNS) infections in adults are rare because of normal immunity and the existence of the blood brain barrier, which prevents the invasion of pathogenic microorganisms. Liver transplant recipients are at an increased risk of opportunistic infections (OI) due to immunosuppressive therapy compared to those with normal immunity. Early diagnosis and timely implementation of treatment are critical for the successful treatment of these infections. We present two cases of intracerebral OI after orthotopic liver transplantation (OLT), with different clinical presentations. Patient 1 presented with epileptic seizures, mainly manifested as unresponsiveness, unconsciousness, and coma complicated with involuntary limb twitching. Patient 2 presented with a consciousness disorder, mainly manifested as unclear consciousness content, poor orientation, calculation power, and logical ability. Next-generation sequencing (NGS) examination of the cerebrospinal fluid confirmed human herpesvirus 6 B (HHV-6B) infection in patient 1 and intracranial Aspergillus infection in patient 2. Intracranial OI has insidious onset and atypical clinical manifestations. NGS can allow for the proper diagnosis and monitoring of the effects of treatment.

A Risk Assessment Model for Stroke in the Early Post-Transplant Period in Adult Cardiac Allograft Recipients: A UNOS Database Analysis

BACKGROUND

Stroke risk in adult cardiac allograft recipients in the early postoperative period remains less defined. This study attempts to develop a risk assessment model in this population.

METHODS

Patients (≥18 years of age) between 2005 and 2015 who underwent cardiac transplantation were selected from the United Network for Organ Sharing database. The final study cohort had 20,915 patients. Risk factors were identified and multivariate logistic regression was used to test associations. SAS software was used for analyses.

RESULTS

Male recipients had a lower risk (odds ratio [OR] 0.7 [0.6-0.92]; P < .05) for stroke. Prolonged ischemic time (OR 1.2 [1.1-1.3), mechanical ventilation (OR 1.6 [1.2-1.9]), left ventricular assist device support (OR 1.8 [1.4-2.3]), black or Hispanic ethnicity (OR 1.33 [1.04-1.7]), days in status 1A (OR 1.05 [1.01-1.1]), recipient creatinine (OR 1.2 [1.02-1.4]), and type 2 diabetes (OR 1.4 [1.1-1.7]) were significant risk factors. A risk score was generated. Patients with a score of 8 had a 5-fold increase in event rate as compared with those with a score of 0. The c-statistic for this model was 0.65.

CONCLUSIONS

For the first time, a weighted risk score GIMVECH (female gender, ischemic time, mechanical ventilation, left ventricular assist device support, ethnicity, clinical history) was generated to assess stroke in the early post-transplant period.

Impact of mechanical circulatory support on post-transplant stroke risk

The effect of type of mechanical circulatory support on stroke risk during the early post-transplant period remains undefined in patients bridged to transplant. This study assesses if the type of circulatory support device affects stroke risk in this population. The study cohort of 4257 adult patients bridged with mechanical support to cardiac transplant were derived from the UNOS transplant registry data. Risk factors assessed were age, gender, ischemic time, diabetes (recipient), durable mechanical support at listing and mechanical ventilation pre-transplant. Descriptive statistics were used to describe characteristics of the study cohort. Univariate logistic regression was used to test if there is a significant association between stroke event and all the potential risk factors. Multivariate logistic regression was used to test such associations while adjusting for all other risk factors. Odds ratios (ORs) and their 95% confidence intervals (CIs) in parenthesis, were calculated. p < 0.05 was considered significant. Patients on Extracorporeal membrane oxygenation (ECMO) had the highest risk of stroke immediately post-transplant prior to discharge (OR 3.03, {1.16, 7.95}) followed by Total Artificial Heart (TAH) (OR 2.03, {1.01, 4.07) as compared to those only on a Left Ventricular Assist Device (LVAD). Ischemic time (OR 1.3 {1.09, 1.45}) and diabetes (OR 1.8 {1.29, 2.51}) were significant risk factors. Patients on ECMO and TAH had a 203% and 103% increase respectively in the odds of having a stroke prior to discharge as compared to those only on LVADS.

Posterior Reversible Encephalopathy Syndrome Associated with Tacrolimus in Cardiac Transplantation

Background

Neurological complications occur between 50 and 70% of patients with heart transplantation, including cerebrovascular events, infections, seizures, encephalopathy, and neurotoxicity due to pharmacological immunosuppression. Mortality associated with cerebrovascular complications is 7.5% in the first 30 days and up to 5.3% after the first month and up to the first year after transplantation. Case Reports. Three heart-transplanted patients (2 men and 1 woman) treated with tacrolimus were identified. They presented with posterior reversible encephalopathy syndrome on days 5, 6, and 58 posttransplantation, respectively. In these reported cases, no sequelae were observed at 6 months follow-up.

Conclusions

Posterior reversible encephalopathy syndrome as a neurological complication in patients with HT occurred early after the procedure. Early diagnosis and treatment might reduce the risk of serious complications and mortality.

Risk Factors Associated With Peripheral Neuropathy in Heart Failure Patients Candidates for Transplantation

INTRODUCTION

Peripheral neuropathy can affect patients with heart failure, though its prevalence is unknown. After heart transplantation, it can influence the postoperative course and quality of life, but screening for neuromuscular disease is not routinely performed.

OBJECTIVE

The aim of this study was to identify the factors associated with neuropathy in a population of patients with heart failure who are candidates for heart transplantation.

STUDY DESIGN

Data regarding patients' clinical history, including recent hospitalizations, were collected. All patients underwent a complete neurological examination and a neurophysiological protocol including nerve conduction studies and concentric needle electromyography.

RESULTS

Thirty-two patients were included in the study, and neuropathy was diagnosed in 10 (31.3%). Neuropathy was associated with the number of admissions ( P = .023; odds ratio [OR]: 1.96) and the total number of days of hospitalization in the year prior to inclusion in the study ( P = .010; OR: 1.03). The majority of hospitalizations occurred in the step-down unit (85%), with acute heart failure the leading cause of admission (42%).

CONCLUSIONS

This study shows that neuropathy is frequent in patients with advanced heart failure and that hospitalization for cardiac care, also in the absence of intensive care, is a marker of high risk of neurologic damage. These data can help physicians in selecting and managing candidates for transplantation and can guide decisions on the best immunosuppressive regimen or rehabilitation strategy.

Seizures after transplantation

PURPOSE

To summarize information on the history, incidence, clinical manifestation, best treatment, as well as prognosis of seizures in transplant recipients.

METHODS

In October 2017, we searched the literature on PubMed in English with the search terms: "transplantation" AND "seizure", "transplantation" AND "epilepsy", "transplantation"AND "status epilepticus", "immunosuppressant" AND "seizure", "immunosuppressant" AND "epilepsy". Publications not based on new data and original research were not included in this article.

RESULTS

Seizures including generalized seizures, focal seizures and status epilepticus are a common central nervous system complication after transplantation. The incidence of seizures varied between different kinds of transplantations. The reported incidence of seizures was 7%-27% in association with solid organ transplantations and 1.6%-15.4% with hematopoietic stem cell transplantation. Most of seizures appeared in the early post-transplantation period. Patients often had a favorable prognosis, however, in some conditions, recurrent or intractable seizures may occur.

CONCLUSIONS

The underlying pathogenesis of new-onset seizures or epilepsy in recipients of transplantation needs to be further elucidated. In addition, more information is required from prospective studies and research focusing on therapeutic strategies.

Long-term outcomes and management of the heart transplant recipient

Cardiac transplantation remains the gold standard in the treatment of advanced heart failure. With advances in immunosuppression, long-term outcomes continue to improve despite older and higher risk recipients. The median survival of the adult after heart transplantation is currently 10.7 years. While early graft failure and multiorgan system dysfunction are the most important causes of early mortality, malignancy, rejection, infection, and cardiac allograft vasculopathy contribute to late mortality. Chronic renal dysfunction is common after heart transplantation and occurs in up to 68% of patients by year 10, with 6.2% of patients requiring dialysis and 3.7% undergoing renal transplant. Functional outcomes after heart transplantation remain an area for improvement, with only 26% of patients working at 1-year post-transplantation, and are likely related to the high incidence of depression after cardiac transplantation. Areas of future research include understanding and managing primary graft dysfunction and reducing immunosuppression-related complications.

Post-cardiac transplant recipient: Implications for anaesthesia

The annual heart transplant rate is gradually increasing worldwide. A proportion of this patient population present for an elective or emergency surgery which may or may not be related to the transplanted heart. A MEDLINE search for heart transplant, anaesthesia, adult, paediatric and surgery was conducted to review anaesthetic management for heart transplant recipients. Anaesthesia and perioperative management are different in these cases. A thorough understanding of the physiology of denervated heart, post-transplant morbidities and pharmacology of immunosuppressants is essential for best perioperative management and improved post-operative outcome.

Epilepsy After Heart Transplant: A Single Center Experience

OBJECTIVES

Cardiac transplant is the best treatment for patients with end-stage heart failure. Neurologic complications occur at a rate of 30% to 80% in patients undergoing cardiac transplant. Seizures occur at a rate of 2% to 20%. The main causative factors include immunosuppressant drug toxicity, infections, brain lesions, and metabolic disorders. Here, our aim was to determine seizure types and associated conditions in patients undergoing cardiac transplant and to report our treatment experience at our institution.

MATERIALS AND METHODS

We retrospectively evaluated the medical records of 109 patients who underwent cardiac transplant between 2004 and 2016. We recorded demographic data, immunosuppressive treatment, seizure type, cause, recurrence rate, and treatment.

RESULTS

Of 109 patients, 13 had seizures after cardiac transplant. Our study involved 69 adult and 40 pediatric patients. The pediatric patients had an age range of 1 to 17 years, with a mean age of 9.6 years (22 female and 18 male patients). Five pediatric patients had seizures (4 female and 1 male patient). The seizure causes included 2 postarrest hypoxic encephalopathies and 3 posterior reversible encephalopathies. Adult patients ranged from 18 to 63 years old, with a mean age of 42.3 years (54 male and 15 female patients). Eight patients in the adult patient group had seizures (5 female and 3 male patients). Seizure causes were ischemic cerebrovascular events in 2 patients, metabolic disorders in 2, posterior reversible encephalopathies in 3, and postarrest hypoxic brain in 1.

CONCLUSIONS

Seizure is an important complication after cardiac transplant. At our institution, the most common cause of seizure was posterior reversible encephalopathy, with immunosuppressant drugs being responsible.

Neurologic Complications After Cardiac Transplant

OBJECTIVES

Cardiac transplant is the best available therapy for patients with end-stage heart failure. Neurologic complications occur at a rate of 30% to 70% in patients undergoing cardiac transplant, and they affect mortality and morbidity of these patients. Risk factors for neurologic complications include immunosuppressive medication toxicity, infections, brain lesions, and metabolic disorders. The aim of our study was to determine the incidence of neurologic complications in adult patients undergoing cardiac transplant.

MATERIALS AND METHODS

We retrospectively evaluated the medical records of 70 patients who underwent cardiac transplant between 2004 and April 2016. We recorded the demographic data, neurologic symptoms, neurologic examination findings, laboratory test results, brain imaging study results, and treatments received of the patients.

RESULTS

Of the 70 patients enrolled, 55 were male and 15 were female patients. The age range was 18 to 63 years, and the mean age was 42.4 years. Twelve patients had encephalopathy, 4 had neuropathic pain, 3 had tremor, 2 had ischemic cerebrovascular accident, 7 had posterior reversible encephalopathy syndrome, and 1 had drop foot. Encephalopathy usually developed secondary to other neurologic disorders. The incidence of neurologic complications in adult patients undergoing cardiac transplant was 30%.

CONCLUSIONS

Neurologic complications are common after cardiac transplant. We observed an incidence of 30% for neurologic complications in our clinic, with encephalopathy being the most common complication. Encephalopathy most commonly developed secondary to posterior reversible encephalopathy syndrome.

Ischemic Stroke after Heart Transplantation

Cerebrovascular complications after orthotopic heart transplantation (OHT) are more common in comparison with neurological sequelae subsequent to routine cardiac surgery. Ischemic stroke and transient ischemic attack (TIA) are more common (with an incidence of up to 13%) than intracranial hemorrhage (2.5%). Clinically, ischemic stroke is manifested by the appearance of focal neurologic deficits, although sometimes a stroke may be silent or manifests itself by the appearance of encephalopathy, reflecting a diffuse brain disorder. Ischemic stroke subtypes distribution in perioperative and postoperative period after OHT is very different from classical distribution, with different pathogenic mechanisms. Infact, ischemic stroke may be caused by less common and unusual mechanisms, linked to surgical procedures and to postoperative inflammation, peculiar to this group of patients. However, many strokes (40%) occur without a well-defined etiology (cryptogenic strokes). A silent atrial fibrillation (AF) may play a role in pathogenesis of these strokes and P wave dispersion may represent a predictor of AF. In OHT patients, P wave dispersion correlates with homocysteine plasma levels and hyperhomocysteinemia could play a role in the pathogenesis of these strokes with multiple mechanisms increasing the risk of AF. In conclusion, stroke after heart transplantation represents a complication with considerable impact not only on mortality but also on subsequent poor functional outcome.