Morphologic expression of the right coronary artery in horses. Comparative description with humans, pigs and other animal species

Abstract

ABSTRACT. The objective of this research was to characterise morphologically the right coronary artery and its branches in the horse. The right coronary arteries of 120 horse hearts were perfused with semi-synthetic resin (85% Palatal GP40L; 15% styrene) and mineral red dye. The morphological and biometric characteristics of the right coronary artery and its branches (digital calibrator) were assessed. The diameter of the right coronary artery was 6.72 ± 2.58 mm. The interventricular subsinusal branch ended at the apex in 94 specimens (78.4%). The right circumflex branch originated at the site of intersection of the subsinnusal interventricular sulcus and the atrioventricular septum, extended along the coronary sulcus with a convoluted trajectory, ended at the obtuse edge of the heart or even at the anterior aspect of the left ventricle in 62 hearts (52.5%), and at the middle segment of the left ventricle in 42 cases (35.6%), whereas in 14 samples (11.9%) it ended at the adjacent surface of the left ventricle. The right conus branch was found in 98 specimens (81.6%) and in 2 of them (1.7%) it emerged directly from the right aortic sinus (third coronary artery). The hearts exhibited right coronary dominance in 118 specimens (98.3%) and in 2 specimens (1.7%) the coronary dominance was balanced. No myocardial bridges were observed. The high incidence of right coronary dominance observed in this study is consistent with previous studies. Due to its similarity with the human heart, we may ratify the equine model for procedural and hemodynamic applications.Key words: horse, coronary artery, dominance, heart.RESUMEN. El objetivo de esta investigación fue caracterizar morfológicamente la arteria coronaria derecha del caballo y sus ramas. En 120 corazones de caballo se perfundieron las arterias coronarias derechas con resina semisintética (palatal GP40L al 85%; estireno al 15%) y color rojo mineral. Se evaluó las características morfológicas y biométricas de la arteria coronaria derecha y sus ramas (calibrador digital). El diámetro de la arteria coronaria derecha fue 6,72 +/-2,58 mm. La rama interventricular subsinusal finalizó en el ápex en 94 especímenes (78,4%). La rama circunfleja derecha se originó a nivel del sitio de cruce del surco interventricular subsinusal y el septum atrioventricular, se extendió a lo largo del surco coronario con una trayectoria contorneada y finalizando en el borde obtuso del corazón o incluso en la cara anterior del ventrículo izquierdo en 62 corazones (52,5%) y en el segmento medio del ventrículo izquierdo en 42 casos (35,6%), mientras que en 14 muestras (11,9%) esta finalizó en la superficie adyacente del ventrículo izquierdo. La rama derecha del cono, se encontró en 98 especímenes (81,6%) y en 2 corazones (1,7%) emergió directamente del seno aórtico derecho (tercera coronaria). Los corazones presentaron dominancia coronaria derecha en 118 muestras (98,3%) y en 2 casos (1,7%) la dominancia coronaria fue balanceada. No se observó puentes miocárdicos. La alta incidencia de dominancia coron...

Two-dimensional echocardiographic measurements of the right coronary artery in healthy horses – a pilot study

“…The ultrasonographic diameter of the RCA measured in the present study is larger than that of the proximal diameter obtained by Gomez et al measured in isolated equine hearts (6.72 ± 2.58 mm) [1]. Those authors obtained similar measurements of the LCA (mean diameter 6.76 ± 21 mm) from the same animals [14]. The measurements presented in the current study are also larger than those reported by Thuroff et al (8.91 ± 0.11 mm) [15].…”

“…These differences may be attributed to different methodologies used to measure the vessel (in vitro measurements vs in vivo measurements), the level at which the vessel was measured and the study sample size. In addition, the authors of previous studies carried out measurements of hearts from younger horses up to 3.5 years old and weighing from 250 to 300 kg [1, 14]. The animals from the present study were older and larger.…”

“…This is the first study that describes the 2D ultrasonographic measurements of the RCA in healthy adult warmblood horses with different levels of training and of various ages. The RCA, and not the LCA, was used in this study as it is a dominant coronary vessel in the horse and fairly easy to visualize during the ultrasound examination [1, 2]. RCA is a relatively small structure, so it is often difficult to visualize its wall boundaries.…”

“…Coronary artery dominance is based on these features. Right-dominance has been reported in horses [1, 2]. The dimensions of coronary arteries have biological relevance.…”

“…To the authors’ best knowledge, this is the first study focusing on the ultrasonographic RCA measurements in the horse. There have been very few estimates of normal coronary morphology in this species and they have mainly focused on the anatomical structure of the vessel in isolated hearts [1, 2, 14, 15]. There are also numerous studies assessing the effect of age and level of training on the heart size, although none of these focus on equine coronary vessels [16–20].…”