Aorto-right atrial fistula. A rare complication of aortic dissection.

Abstract

The consequences of rupture of an aortic dissection into the interatrial space include the development of an aorto-right atrialfistula. A case of aorto-right atrialfistula with successful surgical repair is described, and the typical clinical features of this syndrome are outlined. The pathogenesis of this complication is also discussed.The complications of aortic dissection include occlusion of the vessels arising from the aorta, haemopericardium, pleural effusion, and the development of aortic incompetence. Among the less common complications is haematoma of the interatrial septum (Yacoub, Schottenfeld, and Kittle, I972). Rarely, such a haematoma may rupture into the right atrium thereby giving rise to an aorto-right atrial fistula (Dulake and Ashfield, I964; Kuipers and Schatz, I963; Temple, Rainey, and Anabtawi, I966).This report describes such a case in which surgical repair was successful. Case reportThe patient, a man, aged 54, presented in June I966 after the sudden onset of central chest pain radiating into his right arm, back, lower abdomen, and legs. On admission, he was initially hypotensive, but subsequently his blood pressure rose to 220/IIO mmHg before hypotensive treatment was instituted. The abnormal cardiac findings included a collapsing pulse, a continuous murmur at the right sternal edge, and an early diastolic murmur at the left lower end of the stemum. All peripheral pulses were present and equal. Electrocardiogram showed sinus rhythm with a normal PR interval, a mean QRS axis of -330, and complete right bundle-branch block. Chest x-ray showed cardiac enlargement with dilatation of the ascending aorta. A mass miniature chest x-ray performed in i96o had shown a similar appearance. There was no other past history.He recovered quickly from this initial attack, but after discharge from hospital he noted chest pain on severe exertion. Cardiac catheterization was carried out and confirmed aortic dissection extending from the aortic valve region to below the diaphragm. There was no evi-1 Present address: The London Hospital, London Ei.dence of a left-to-right shunt from oxygen saturation data nor from aortography. In I972, he began to notice increasing exertional dyspnoea in addition to angina. The heart size had increased on chest x-ray. An electrocardiogram now showed the development of first-degree atrioventricular block in addition to the previously noted right bundlebranch block. In view of his clinical and radiological deterioration, operation was recommended.At operation in November I972, there was an aneurysm of the ascending aorta measuring 25 cm in diameter. A transverse intimal tear 5 cm in length was situated I 5 cm above the left and non-coronary sinuses. The lower part of the dissection displaced the commissure between the left and non-coronary cusps resulting in prolapse of these cusps. There was a fistula measuring 3 to 4 mm in diameter into the right atrium from the false lumen of the aorta (Fig. I).The aneurysm was excised leaving a 3 cm cuff of aortic wall around the fistula fo...

Type A Aortic Dissection Complicated by an Aorto-Right Atrial Fistula

“…In this review, the fistula tract formed between the aorta and RA in the majority of patients, which can be explained by considering the anatomy of the aortic root . The RA lies adjacent to the right lateral and posterior aspect of the aortic root .…”

“…The RA lies adjacent to the right lateral and posterior aspect of the aortic root . In this region, the aorto‐atrial space is filled by loose areolar tissue, bound on one side by the RA and tricuspid valve ring and on the opposite side by the noncoronary sinus and membranous ventricular septum . As the media is not continuous with the aortic valve annulus at the commissures, a dissection involving the commissure between the non‐ and right‐coronary sinuses may propagate into the interatrial septum .…”

“…In this region, the aorto‐atrial space is filled by loose areolar tissue, bound on one side by the RA and tricuspid valve ring and on the opposite side by the noncoronary sinus and membranous ventricular septum . As the media is not continuous with the aortic valve annulus at the commissures, a dissection involving the commissure between the non‐ and right‐coronary sinuses may propagate into the interatrial septum . Subsequently, the dissection may rupture into the RA or extend the down septum into the RV, injuring the bundle of His .…”

“…In this review, the fistula tract formed between the aorta and RA in the majority of patients, which can be explained by considering the anatomy of the aortic root. 17 The RA lies adjacent to the right lateral and posterior aspect of the aortic root. 18 In this region, the aorto-atrial space is filled by loose areolar tissue, bound on one side by the RA and tricuspid valve ring and on the opposite side by the noncoronary sinus and membranous ventricular septum.…”

“…17 Subsequently, the dissection may rupture into the RA or extend the down septum into the RV, injuring the bundle of His. 17,19 Other authors have speculated that adhesions from previous cardiac surgical procedures may prevent rupture of the dissection into the pericardium and favor the formation of an ARHF. 20 This theory may account for the high proportion of patients in this review with a history of previous cardiac surgery.…”