6.10.1 Rupture of the aortic root
Rupture of the aortic root is a rare condition which is reported most frequently in aged stallions. It is thought to result from necrosis and degeneration of contissue in the aortic wall. Blood penetrates the myocardium surrounding the base of the aorta 'dissecting' the tissue. Usually the dissection runs into the basal part of the IVS from the right coronary sinus. Animals may die suddenly or may present with acute cardiac decompensation. Distress and signs of pain can be seen. A sinus tachycardia is likely to be present, although junctional or ventricular tachycardias have been reported with dissection of IVS. These arrhythmias may be life threatening and may require immediate treatment (see section 7.8.9).
Diagnosis of a rupture of the aortic root is made on echocardiographic examor at PM. On echocardiography, an area of hypoechogenicity may be seen in the IVS if the dissection has taken this route. The area around the aortic root may appear abnormal; however, changes may not be very dramatic. Freother abnormalities such as aortic valve disease or MV disease may be present and murmurs associated with these conditions may be noted on clinical examination.
The prognosis for animal with a rupture of the aortic root is very poor and, although they may recover from the initial period of distress and tachycardia, a recurrence of signs or sudden death are likely at a later date.