Internal carotid artery dolichoarteriopathies in the horse: An endoscopic and anatomic study.

This research article studies the unusual aspects of the internal carotid arteries (ICAs) in newborn horses, terming these as ‘dolichoarteriopathies’. The aim was to understand whether these irregularities, seldom seen in adult horses, could be classified as tortuous, kinked, or coiled. The study included endoscopic inspection of 50 young horses and anatomical study of 20 horse carcasses, finding that these anomalies in the ICAs were mostly prevalent in horses less than four weeks old and not in the adults. These anomalies appear to be not pathological, but rather simple transient anatomical variability.

Objective and Background

• The research aimed to throw light on the irregularities occasionally observed in the ICAs of young horses using endoscopic and anatomic studies.
• Dolichoarteriopathies refer to anomalies in the course and geometry of ICAs, and can be classified into tortuous, kinked or coiled.
• These types of irregularities have been widely studied in human medicine, but data is limited and insufficient in veterinary science, particularly in relation to domestic mammals.

Methodology

• Two studies were conducted. One involved an endoscopic study of the guttural pouch – a respiratory air sac present in the horse, in 50 foals less than four weeks of age.
• The other was an anatomical study, carried out on the heads of 20 fresh horse carcasses – 13 one-month-old foals, 1 seven-month-old and 6 adults, using vascular casts to study the extracranial tracts of the ICAs.

Findings

• Anomalies in the ICAs were observed only in foals less than four weeks old and were absent in adults.
• The presence of these anomalies was confirmed via both endoscopic and anatomical studies, revealing that about 66% to 71% of the animals had dolichoarteriopathies, in most instances on both sides.
• Tortuosity was observed to be the most common anomaly, and there seemed to be no difference between the genders in terms of susceptibility.

Conclusion

• The study hypothesises that these anomalies could occur due to the excess length of the ICA in relation to the distance between its origin and its entry into the cranial cavity.
• Based on this, it is proposed that the irregularities observed in the ICAs of foals – tortuosity, kinking and coiling, should not be considered as pathological but rather a temporary anatomical variation.