Surgical Closure of Coronary Cameral Fistula Draining into the Left Ventricle via a “Fistula Lake”

A left-sided lesion of a coronary cameral fistula (CCF) is extremely rare. Surgical closure of the fistula is indicated when symptoms emerge or as a preventive strategy, while surgical approaches depend on the individual anatomical structures. In particular, a CCF forming a “fistula lake” with multiple inflow vessels is so unique that few studies have focused on the technique to close it. We report the successful management of a CCF originating from multiple coronary arteries and draining into the left ventricle via a “fistula lake” by ligation and clipping of associated communication tracts. On the postoperative coronary computed tomography angiography, the fistula lake and the small vessels entering it had all disappeared.


Introduction
A coronary cameral fistula (CCF) must be closed when any symptoms emerge or as a preventive strategy. Most CCFs originate from right coronary arteries, and >90% of CCFs drain into the right heart structures [1]. A CCF connecting multiple coronary arteries and the left ventricle is thus quite rare. Though several types of surgical techniques reported to date include the ligation or division of the fistula, closing the fistula directly, and closing it with an autologous pericardial patch from the inside of the cardiac chamber or pulmonary artery, few have referred to how to manage a CCF forming a "fistula lake" with multiple inflow vessels explicitly [2]. According to Lowe and colleagues, the diffusely distributed How to cite this paper: Cao, Y.C., Koide, M., Kunii, Y., Tateishi, M., Watanabe, K., Okugi, S., Sakurai, Y. and Shimbori, R. (2020) Surgical Closure of Coronary Cameral Fistula Draining into the Left Ventricle via a "Fistula Lake". World Journal of Cardiovascular Diseases, 10, 545-549.

Case Presentation
The patient was a 52-year-old Japanese man with a medical history of dyslipidemia and chronic heavy cigarette smoking, and was prescribed with Rosuvasta-  between an epicardial coronary artery and a cardiac chamber. Most cases of CCF are asymptomatic, detected incidentally, and conservatively managed with continual follow-up [4]. However, CCFs must be surgically closed when any hemodynamically significant situation, such as myocardial ischemia or congestive heart failure, emerges. Surgical closure may also be performed as a preventive strategy, to preclude aneurysm formation, infective endocarditis, and other cardiac disorders [2]. Our patient presented with worsening exertional chest pain, and coronary angiography showed significant stenosis of the LAD and a CCF originating predominantly from the LCx and draining into the left ventricle, which suggested the coronary steal phenomenon.

Discussion
Since its first description by Biörck and Crafoord in 1947 [5], surgical repair of a coronary fistula has been the most effective treatment [6]. There are reports of CCFs being treated by transcatheter procedures, including coils, plugs, or detachable balloons [7], but these devices carry the risk of migrating within the coronary artery branches or to the extracoronary vascular structures [8]. Although various surgical techniques have been reported for fistula repair, few studies have focused on the procedure for a fistula lake with multiple inflow vessels. In our case, the lake had multiple inflow vessels but only one outflow vessel. As the inflow tracts were small and assumed to be difficult to completely detect, we assigned the highest priority to closure of the outflow tract. The outflow vessel was identified and closed by both ligation and clipping, followed by clipping of the inflow vessels to the extent possible. As a result, postoperative CCTA revealed the disappearance of all fistulous tracts as well as the fistula lake.
Since the site surrounding the fistula lake was the posterior aspect of the heart just adjacent to the coronary sinus, we chose to repair the fistula with the patient under cardiac arrest using cardiopulmonary bypass. This made sufficient heart displacement possible so that we could safely reach the posterior wall just adjacent to the coronary sinus and fully define the entire fistulous network.
Although surgical management remains the most effective treatment for CCFs, Basit et al. reported a case of surgical failure 6 years after closure of a CCF, indicating that CCFs can persist or recur after surgical ligation [9]. Longer and more rigorous follow-up of patients with CCFs is thus necessary.
This case report has potential limitations. Our strategy aimed at closing all of the fistulous tracts detectable which resulted in the disappearance of the left-to-right shunt. Since intervention may become more difficult or impossible when the fistulas are diffuse, despite the ischemia in the patient, sometimes intervention should not be considered. Symptoms can be relieved by therapy with metoprolol or calcium channel blockers [10].

Conclusion
We surgically repaired a CCF originating from multiple coronary arteries, including the LAD, LCx, and RCA, and draining into the left ventricle via a fistula lake. The complete obliteration of all fistulous tracts was accomplished by the li-gation and clipping of the outflow vessel from the lake into the left ventricle and the multiple inflow vessels originating from the coronary arteries.