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Updated: Oct 14, 2025
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Findings suggestive of coronary microvascular dysfunction in cats with myocardial ischemia
Guillermo Belerenian1, Pablo Alejandro Donati2,3, Cristian Daniel Rodriguez1,2,3,4,5
1Luis Pasteur Zoonosis Institute,, Buenos Aires, Argentina.
Insights
Coronary microvascular dysfunction (CMD) was identified in cats with myocardial infarction and normal coronary arteries. This suggests microvascular dysplasia may cause heart disease in felines, warranting further investigation.
Area of Science:
- Veterinary Pathology
- Cardiology
- Comparative Medicine
Background:
- Myocardial infarction (MI) is a leading cause of death globally, with a subset of human patients exhibiting normal coronary arteries.
- This presentation in humans is linked to coronary microvascular dysfunction (CMD), a condition affecting cardiac microvasculature.
- Limited research exists on MI and CMD in small animals, particularly cats.
Purpose of the Study:
- To investigate necropsy findings in cats with histopathological evidence suggestive of CMD.
- To characterize the clinical-pathological aspects of CMD in feline subjects.
Main Methods:
- Retrospective evaluation of necropsy records from cats diagnosed with acute and/or chronic MI.
- Inclusion criteria focused on cases with normal epicardial arteries and observed microvascular disorders.
- Histopathological examination of myocardial tissues was performed.
Main Results:
- Twenty cats met the inclusion criteria for the study.
- Fifty percent of cats presented with severe hypertrophic cardiomyopathy (HCM) and left atrial enlargement; others showed mild HCM, restrictive, or histiocytoid cardiomyopathy.
- All cases revealed normal epicardial arteries, multifocal myocardial fibrosis, and vascular changes indicative of microvascular pathology.
Conclusions:
- The observed histopathological findings suggest the presence of coronary artery microvascular dysplasia in these feline cases.
- Further research is required to confirm these findings and establish a clinical characterization of CMD in cats.
Background:
Myocardial infarction (MI) is an important cause of death and disability among humans worldwide. Few studies have reported the occurrence of MI in small animals as well. Reports in human medicine indicate that up to 30% of patients with clinical signs compatible with myocardial ischemia suggestive of coronary disease exhibit normal epicardial arteries at angiography. These symptoms have been associated with a syndrome characterized by alterations in cardiac microvasculature, known as coronary microvascular dysfunction (CMD).
Aim:
This study aimed to describe the necropsy findings and clinical-pathological characterization (when available) of cats with histopathological findings suggesting CMD.
Methods:
Necropsy records of cats presenting histopathological diagnosis compatible with acute and/or chronic MI, with normal epicardial arteries and microvascular disorders were evaluated.
Results:
Twenty animals met the inclusion criteria. Eight cats (40%) exhibited findings compatible with mild hypertrophic cardiomyopathy (HCM) without left atrial enlargement, one (5%) presented restrictive cardiomyopathy, and another one (5%) had lesions consistent with histiocytoid cardiomyopathy. The remaining cats (50%) showed alterations compatible with severe HCM with left atrial enlargement. In all cases, epicardial arteries were normal (without obstruction). All the evaluated hearts exhibited myocardial multifocal fibrosis along with replacement of cardiomyocytes by adipose tissue and blood vessels with hyperplasia and hypertrophy of the muscular layer with protrusion of the nuclei of the endothelial cells.
Conclusion:
These findings suggest the presence of microvascular dysplasia of the coronary arteries. Further studies are necessary to confirm and clinically characterize these results.
