Guillermo Belerenian(1), Pablo Alejandro Donati(2,3), Cristian Daniel Rodriguez(2), Victor Castillo(1), Juan Manuel Guevara(2), Claudia Pucheta(1), Sergio Ferraris(4) and Roberto Walter Israel Olivares(5*)
1- Luis Pasteur Zoonosis Institute. Av. Díaz Vélez 4821, C1405 DCD, Buenos Aires, Argentina
2- UCICOOP. Av Jose María Moreno 635, C1424 AAG, CABA, Bs. As., Argentina
3- Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Anestesiología y Algiología, Av. Chorroarín 280, CP 1427, Ciudad Autónoma de Buenos Aires, Argentina
4- Research and Experimental Models Center, Maimonides University. Hidalgo 775, C1405 CABA, Argentina
5- Servicio de Patología Diagnóstica LAPAVET-ESFA. Cátedra de Patología e Histología, Escuela de Medicina y Cirugía Veterinaria San Francisco de Asís, Universidad Veritas. Vázquez de Coronado, San José, Costa Rica
Background: Myocardial infarction is an important cause of death and disability among humans worldwide. Few studies have reported the occurrence of myocardial infarction 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.
Aim: This study aimed to describe the necropsy findings and clinical-pathological characterization (when available) of cats with histopathological findings suggesting coronary microvascular dysfunction.
Methods: Necropsy records of cats presenting histopathological diagnosis compatible with acute and/or chronic myocardial infarction, 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 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 hypertrophic cardiomyopathy 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.
Keywords: Coronary microcirculation, microvascular dysfunction, feline ischemia.