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Updated: Feb 10, 2026
A Porcine Heterotopic Heart Transplantation Protocol for Delivery of Therapeutics to a Cardiac Allograft
Published on: February 14, 2022
Coronary microvasculopathy in heart transplantation: Consequences and therapeutic implications
Alessandra Vecchiati1, Sara Tellatin1, Annalisa Angelini1
1Alessandra Vecchiati, Sara Tellatin, Annalisa Angelini, Sabino Iliceto, Francesco Tona, Department of Cardiac, Thoracic and Vascular Sciences, Padova University Hospital, 35128 Padova, Italy.
Insights
Cardiac allograft vasculopathy (CAV) is a major cause of death after heart transplantation, characterized by microvascular dysfunction. This review analyzes CAV mechanisms, consequences, and therapeutic strategies for improved patient survival.
Area of Science:
- Cardiology
- Immunology
- Vascular Biology
Background:
- Cardiac allograft vasculopathy (CAV) is the primary cause of late mortality in heart transplant recipients.
- CAV involves progressive intimal hyperplasia and smooth muscle cell proliferation, leading to vessel wall thickening across epicardial and microvascular beds.
- Current understanding suggests a complex interplay of immunologic (HLA compatibility, T-cell, humoral responses) and non-immunologic factors (donor age, ischemia-reperfusion, hyperlipidemia, CMV) contribute to endothelial damage and inflammation.
Purpose of the Study:
- To review the mechanisms, consequences, and therapeutic implications of microvascular dysfunction in cardiac allograft vasculopathy.
- To highlight the limitations of current diagnostic techniques for assessing microvascular function in heart transplant patients.
- To synthesize relevant literature data on CAV pathogenesis and management.
Main Methods:
- Literature review focusing on immunologic and non-immunologic factors contributing to CAV.
- Analysis of diagnostic modalities for epicardial and microvascular coronary artery disease.
- Discussion of proposed indices for microcirculatory resistance and non-invasive physiological assessment methods.
Main Results:
- CAV pathogenesis involves both immune and non-immune triggers leading to sustained inflammation and endothelial damage.
- Existing diagnostic tools like intravascular ultrasound and fractional flow reserve are insufficient for detecting microvascular changes.
- Novel methods for assessing microvascular function, such as microcirculatory resistance indices and non-invasive imaging, are under investigation.
Conclusions:
- Microvascular dysfunction is a critical component of cardiac allograft vasculopathy, significantly impacting long-term heart transplant outcomes.
- There is a pressing need for improved diagnostic tools to accurately assess and monitor microvascular function post-transplant.
- Further research into the mechanisms and therapeutic strategies targeting microvascular dysfunction is essential for improving survival rates in heart transplant recipients.
Abstract:
Despite the progress made in the prevention and treatment of rejection of the transplanted heart, cardiac allograft vasculopathy (CAV) remains the main cause of death in late survival transplanted patients. CAV consists of a progressive diffuse intimal hyperplasia and the proliferation of vascular smooth muscle cells, ending in wall thickening of epicardial vessels, intramyocardial arteries (50-20 μm), arterioles (20-10 μm), and capillaries (< 10 μm). The etiology of CAV remains unclear; both immunologic and non-immunologic mechanisms contribute to endothelial damage with a sustained inflammatory response. The immunological factors involved are Human Leukocyte Antigen compatibility between donor and recipient, alloreactive T cells and the humoral immune system. The non-immunological factors are older donor age, ischemia-reperfusion time, hyperlipidemia and CMV infections. Diagnostic techniques that are able to assess microvascular function are lacking. Intravascular ultrasound and fractional flow reserve, when performed during coronary angiography, are able to detect epicardial coronary artery disease but are not sensitive enough to assess microvascular changes. Some authors have proposed an index of microcirculatory resistance during maximal hyperemia, which is calculated by dividing pressure by flow (distal pressure multiplied by the hyperemic mean transit time). Non-invasive methods to assess coronary physiology are stress echocardiography, coronary flow reserve by transthoracic Doppler echocardiography, single photon emission computed tomography, and perfusion cardiac magnetic resonance. In this review, we intend to analyze the mechanisms, consequences and therapeutic implications of microvascular dysfunction, including an extended citation of relevant literature data.
