Spontaneous Closure of an Iatrogenic Circumflex Coronary Artery-to-Coronary Vein Fistula

Coronary artery fistulae are extremely rare¹ and can either be congenital or acquired secondary to cardiac intervention or surgery. They have also been reported following acute myocardial infarction.² The majority of these fistulae arise from the right coronary artery or the left anterior descending artery, with the circumflex artery rarely being involved.^3,4
In the transplanted hearts, coronary artery fistulae are reported to occur as a complication of endomyocardial biopsies.⁵ They commonly occur between the coronary artery and the right ventricular cavity,^6,7 but have also been described to occur between a coronary artery and branches of the coronary sinus.⁸ The patients are generally asymptomatic5 and echocardiographically may demonstrate myocardial hypokinesia secondary to ischemia.⁶
We hereby report a case of a proximal circumflex coronary artery to the great cardiac vein fistula that we discovered incidentally during routine angiographic follow up post-heart transplantation. We believe that it did not occur following an endomyocardial biopsy procedure. The fistula closed spontaneously while we were assessing the patient for percutaneous closure of his fistula.

Case Report. A 54-year-old Caucasian male underwent an orthotopic heart transplant in July 2003 for dilated cardiomyopathy secondary to viral infection. The transplant and the immediate postoperative recovery period were uneventful. The patient was placed on triple immunosuppressive therapy and underwent regular right ventricular endomyocardial biopsies starting on postoperative day 7 to screen for rejection, and these were also uneventful. The patient’s heart rate on postoperative day 8 was 50 beats per minute, and transthoracic echocardiography revealed mild right ventricular dysfunction with preserved left ventricular function. A dual-0chamber pacemaker was implanted on postoperative day 9.
The patient was referred to our center in 2004 for coronary angiography to screen for cardiac allograft vasculopathy. Coronary angiography showed that angiographically there was no evidence of cardiac allograft vasculopathy and that there was a fistulous communication between the proximal circumflex coronary artery and the great cardiac vein, as shown in the RAO caudal and LAO caudal views in Figures 1 and 2, respectively. The patient was asymptomatic and hemodynamically stable and transthoracic echocardiography showed a preserved left ventricular function with no evidence of regional wall motion abnormality. The findings were discussed with the patient and we started to assess him for percutaneous closure of the fistula.
After displacement due to hurricane Katrina, the patient returned to us in March 2006 for follow up. Coronary angiography showed that the fistulous communication had spontaneously closed, as shown in the RAO caudal and LAO caudal views in Figures 3 and 4, respectively. Left ventriculography and transthoracic echocardiography showed preserved left ventricular function with no regional wall motion abnormality. Discussion. This patient presented to us with a proximal circumflex coronary artery-to-great cardiac vein fistula that spontaneously closed in a transplanted heart. We believe that this fistula was not congenital and that it was acquired postoperatively from the cardiac procedures the patient underwent after transplantation. The fact that the fistula closed spontaneously reinforces this theory.
Postoperatively, the patient underwent regular right ventricular biopsies with right heart catheterizations. In addition, the patient underwent dual-chamber pacemaker implantation on day 9 after his heart transplant. Right heart catheterizations are unlikely to produce fistulous communications between a coronary artery and the coronary sinus; they are usually performed using Swan-Ganz catheters with an inflatable balloon at the tip for atraumatic guidance of the catheter tip. It is possible that the right ventricular bioptome was inaccurately placed through the coronary sinus to the great cardiac vein during the screening right ventricular biopsies; however, performing a biopsy at this site, and involving the circumflex coronary artery, would have inadvertently led to serious hemodynamic consequences, which this patient did not experience at any time postoperatively.
The tip of the atrial screw in the lead appears to be in close proximity to the site of the previous fistulous connection in Figure 3. The LAO caudal view in Figure 4 confirms that currently the lead is screwed in the right atrial appendage. It is quite feasible that during the pacemaker implantation, the tip of the atrial lead was passed through the coronary sinus and screwed in the great cardiac vein, as it appeared to be in the right atrium by fluoroscopy. That poor sensing or pacing in the coronary sinus led to repositioning to its current site. Screwing the tip of the right atrial lead led to penetration of the great cardiac vein and the circumflex coronary artery, and removal of the screw in the lead led to the fistulous communication. The fact that cardiac transplant patients develop pericardial fibrous tissues, and the fact that the fistulous communication was very small (the size of the diameter of the screw in the lead), made it possible for the patient to experience no hemodynamic compromise.

The coronary venous system can be considered as first-order tributaries originating from the main coronary sinus (i.e., the small, great, posterior and middle cardiac veins), which then branch into second- and third-order tributaries.⁹ The anterior interventricular vein ascends in the anterior interventricular sulcus (parallel to the left anterior descending coronary artery) from the apex toward the base of the heart and ends in the great cardiac vein. It then turns laterally at the base of the heart, along the left atrioventricular groove (parallel to the circumflex coronary artery), and wraps around the left side of the heart, going posterior to merge with the coronary sinus. In addition to several smaller tributaries from the left atrium and ventricles, the great cardiac vein receives two main branches, namely the large left marginal vein, along the lateral border of the heart, and the posterior left ventricular branch (the posterolateral branch). The great cardiac vein terminates in the coronary sinus, a junction defined by the presence of the left atrial oblique vein. Another important branch is the middle cardiac vein, which runs in the posterior interventricular groove, parallel to the posterior descending coronary artery.
This case emphasizes the need for multiple fluoroscopic views before screwing pacing leads into the myocardium. The use of limited views will lead to erroneous interpretation in the two-dimensional fluoroscopic screen of the three dimensions of the heart. This patient was extremely fortunate not to suffer hemodynamic consequences as a result of creation of the fistula. The patient remains well after the spontaneous closure of the fistula, and echocardiography shows a normal functioning heart.

References

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