Case series of a rare complication of CABG. Fistula between the internal mammary artery and pulmonary vasculature.

BACKGROUND

There are few reports in the literature on the development of a fistulous connection between the left internal mammary artery (LIMA) and the pulmonary vasculature (PV) after coronary artery bypass grafting (CABG). This type of fistula may cause angina after CABG. Various mechanisms in the pathophysiology of this rare condition have been proposed.

METHODS

We evaluated 537 consecutive patients with CABG surgery who underwent coronary angiography at our institution between January 2011 and March 2012. The post-CABG angiograms were evaluated for LIMA-PV fistula formation. Presence of a LIMA-PV fistula was defined as opacification of the PV or parenchyma after injection of radiopaque contrast medium into the LIMA.

RESULTS

We found that 5 of 537 patients (0.93 %) had a LIMA-PV fistula on post-CABG coronary angiograms. The mean age of patients with a LIMA-PV fistula was 61.4 years (range, 51-72 years) and all patients were male. Coronary angiography was performed in the setting of myocardial infarction for 2 patients with a LIMA-PV fistula, and stable angina pectoris was the indication for coronary angiography in the remaining 3 patients. The mean diagnosis time of LIMA-PV fistula after CABG was 3.4 years (range, 1-9 years). None of the patients had a history of redo-CABG, perioperative mediastinitis, or pneumonia.

CONCLUSION

LIMA-PV fistulas may occur more frequently than reported on post-CABG angiogram findings. Angina in post-CABG patients may be associated with a LIMA-PV fistula, and selective cannulation of the LIMA with careful evaluation of the angiographic images may provide proper diagnosis and treatment of this entity.