How is cardiac transplant function being monitored?

From the Guidelines

Cardiac transplant function is monitored through a comprehensive approach that includes regular endomyocardial biopsies, echocardiography, blood tests, and clinical assessments, with echocardiography being a crucial tool for assessing cardiac structure and function, including ejection fraction, wall motion, and valve function 1.

Key Components of Cardiac Transplant Function Monitoring

• Endomyocardial biopsies: typically performed weekly in the first month post-transplant and then gradually decreased in frequency, remain the gold standard for detecting rejection by examining heart tissue samples
• Echocardiography: conducted regularly to assess cardiac structure and function, including ejection fraction, wall motion, and valve function
• Blood tests: monitor immunosuppressive drug levels (tacrolimus, cyclosporine, sirolimus) to maintain therapeutic ranges while avoiding toxicity, and include complete blood counts, metabolic panels, and cardiac biomarkers like troponin and BNP
• Clinical assessments: regular electrocardiograms to detect arrhythmias or conduction abnormalities, while coronary angiography or intravascular ultrasound is performed annually to monitor for cardiac allograft vasculopathy

Role of Echocardiography in Cardiac Transplant Function Monitoring

• Echocardiography is a non-invasive and widely available imaging modality that provides valuable information on cardiac structure and function
• It is recommended to obtain a comprehensive echocardiographic study at 6 months from the cardiac transplantation as a baseline and make a careful quantitation of cardiac chamber size, RV systolic function, both systolic and diastolic parameters of LV function, and pulmonary artery pressure 1
• Global longitudinal strain (GLS) is a suitable parameter to diagnose subclinical allograft dysfunction, regardless of aetiology, by comparing the changes occurring during serial evaluations 1

Other Imaging Modalities Used in Cardiac Transplant Function Monitoring

• Cardiac magnetic resonance (CMR): can be used to assess cardiac chamber volumes and function, and to exclude acute graft rejection and cardiac allograft vasculopathy in patients with inadequate acoustic window despite contrast 1
• Computed tomography (CT) coronary angiography: can be used to detect cardiac allograft vasculopathy, especially in patients with contraindication to CMR or inadequate acoustic window 1
• Intravascular ultrasound (IVUS): can be used to detect cardiac allograft vasculopathy, especially in patients with discrepancy between non-invasive imaging tests and coronary angiography concerning the presence of cardiac allograft vasculopathy 1

From the Research

Cardiac Transplant Function Monitoring

• Cardiac transplant function is typically evaluated using transthoracic echocardiography, which provides reference values for chamber size and function, including cardiac mechanics, in clinically stable heart transplant patients 2.
• Echocardiographic measures, such as ejection fraction and left ventricular global longitudinal strain, are used to assess left ventricular function, while tricuspid annular plane systolic excursion and right ventricular systolic tissue Doppler velocity are used to evaluate right ventricular function 2.
• The distribution of routinely used echocardiographic measures differs between stable heart transplant patients and healthy subjects, with larger right ventricular and atrial volumes and mild reductions in both left and right ventricular longitudinal strain observed in heart transplant patients 2.

Complications and Management

• Cardiac transplant patients may present with a range of issues, including complications due to their transplant, such as graft failure, rejection, and infection, as well as altered presentations of disease resulting from their transplant 3.
• These patients are at risk of infection, dysrhythmias, acute coronary syndrome, cardiac allograft vasculopathy, and medication adverse events, and require careful evaluation and management in the emergency department setting 3.
• Consultation with the transplant physician is recommended to assist in the evaluation and management of these patients 3.

Diagnostic Techniques

• Echocardiography is a useful diagnostic tool in the cardiac transplant recipient, allowing for the identification of clinically significant changes and guiding the endomyocardial biopsy in cases of suspected acute rejection 4.
• Echocardiographic indices, such as the E/e' index, can be used to estimate left ventricular filling pressure in heart transplant recipients, although these parameters should be interpreted with caution 5.
• Right-sided heart catheterization and echocardiography can be used in combination to evaluate left ventricular filling pressure and diagnose cardiac allograft vasculopathy in heart transplant recipients 5.