Presence of coronary to pulmonary fistula is a common finding seen in patients with pulmonary atresia together with ventricular septal defect. Small communications between pulmonary artery and coronary arteries have also been described in patients with Tetratology of Fallot (TOF). However, large coronary to pulmonary artery fistula is a rare finding. In this case report we present a very rare case with multiple significant-sized coronary to pulmonary artery fistulae originating from left main coronary artery (LMCA), circumflex (CX) and right coronary arteries (RCA) in a patient with TOF.

Figure 1. Left anterior oblique left ventriculography demonstrating subaortic VSD and overriding aorta.

A 25-year old male patient with exertional dyspnea and mild cyanosis since childhood had been admitted to our institution. There was no history of cyanotic spells. On physical examination, he had mild central cyanosis and grade 2 clubbing. His blood pressure was 120/70 mmHg, pulse rate was 90 beats per minute with a regular rhythm. Pulse oxymetry revealed O2 saturation of 85%. Cardiovascular system examination revealed normal S1, single S2 and a continuous murmur best heard at left sternal border between second and third intercostal area. Chest roentgenogram showed decreased pulmonary blood flow, right ventricular type of apex and prominent aorta. Electrocardiogram showed sinus rhythm with right ventricular hypertrophy and right axis deviation, there was no evidence of myocardial ischemia. Echocardiography revealed significant subaortic ventricular septal defect (VSD), aortic override, right ventricular hypertrophy with severe pulmonary infundibular stenosis. At cardiac catheterization, the diagnosis of TOF was confirmed with prominent subaortic VSD, aortic override (Figure 1) and pulmonary stenosis. Selective coronary angiography showed significant coronary fistulae to pulmonary arteriolar bed arising from left main, circumflex (Figure 2) and right coronary arteries (Figure 3), all of which at a size equivalent to a major side branch of a main coronary artery. There was also an additional small fistula arising from LMCA. The remaining coronary tree was normal except for fistulae. At surgery, the fistulas were isolated and ligated from their origins, complete closure of VSD with patch, pulmonary infundibular resection, infundibular and right ventricular outflow reconstruction with autologous pericardial patch was done. He did well after surgery and was discharged from hospital uneventfully.

Figure 2. Anteroposterior view demonstrating fistulous communications arising from middle part of LMCA and Cx to right pulmonary hilum.

Coronary fistulas are thought to arise as a persistence of sinusoidal connections between the lumens of the primitive tubular heart that supply myocardial blood flow in the early embryologic period. Congenital coronary to pulmonary fistulas are rare isolated congenital anomalies of coronary vasculature which are reported to be 1/50000 in normal population [1]. They commonly occur unilaterally, mostly arising from RCA (52%), LAD (30%) and CX (18%) [2]. Multiple coronary fistulas are very rare, but occasional fistulas between three major coronary arteries and left ventricle have also been reported [3]. Coronary fistulas are most commonly seen in patients with pulmonary atresia together with VSD however small fistulas associated with TOF have also been described. Study performed by Dabizzi et.al included the largest series, and revealed the frequency of coronary fistula in patients with TOF as 10.9%; all of which were small fistulas. 1.6% of patients had 2 fistulas from different coronary arteries, but there was no case with 3 fistulas originating from different coronary arteries [4] [5]. More recently, significant fistulas between coronary arteries and pulmonary artery were described in patients with TOF. One of these reports was a patient with TOF and significant fistula from CX to pulmonary artery [6] and the other two was associated with LMCA fistula to pulmonary artery [7] [8]. As far as we know, our case is the first one demonstrating significant fistulas between three major coronary arteries and pulmonary arteries.

Figure 3. Left anterior oblique view demonstrating fistula from proksimal right coronary artery to left pulmonary hilum.

There may be various effects of these coronary-pulmonary fistulas in patients with TOF. Since one of the major problems in TOF is reduced pulmonary blood flow, significant collaterals arising from coronaries to pulmonary circulation may increase pulmonary arterial flow. Our patient didn’t have any history of cyanotic spells and we think this may be in part due to increase of pulmonary flow by significant multiple coronary-pulmonary fistulas. On the other hand, these communications should be identified before surgery and ligated before cardioplumonary by-pass to prevent loss of cardioplegic solution to pulmonary vasculature which in turn might lead to incomplete myocardial protection. In addition, although most of the coronary fistulas remain asymptomatic in the first two decades especially when they are hemodynamically small, the fistulas may increase in size over time and the frequency of both symptoms and complications such as myocardial ischemia due to steal phenomenon, thrombosis and embolism, rupture, endocarditis or endarteritis and arrhythmias may increase [9].

The identification of coronary fistulas before surgery is very important in patients with TOF so anatomic evaluation of coronary arteries by cineangiography or coronary computerized tomography should be carried out before surgery in these patients.