Right coronary artery stenosis unmasking ischemia in a patient with bilateral coronary pulmonary fistulas

Introduction

Coronary artery fistulas (CAF) are congenital or acquired formations between the coronary arteries and cardiac chambers or other vascular structures such as the vena cava, pulmonary artery, or veins [1]. Most of these are found incidentally during angiography [2]. Fistulas account for half of all coronary anomalies and are present in 0.002% of the general population. Coronary to pulmonary artery fistulas comprise 15–30% of coronary anomaly cases and only 5% of these involve bilateral coronary arteries [3].

Case report

A 71-year-old man with hypertension, hyperlipidemia, and smoking abuse underwent single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy (MPI) for exertional chest pain (CCS II) which showed borderline inferoseptal reversible perfusion abnormality based on the SPECT 17-segment scoring system (SSS = 3, SRS = 0, SDS = 3) (Figure 1). His vital signs were: heart rate 68 BPM, respiratory rate (RR) 24/min, blood pressure (BP) 133/76 mm Hg, and O2 saturation of 98% on room air. He had normal S1, S2 without murmurs, edema or jugular venous distention. Laboratory data were within normal limits. ECG was normal sinus rhythm without ischemic changes. Transthoracic echocardiogram (TTE) revealed normal ejection fraction of 55%, right ventricular systolic pressure (RVSP) of 40–50 mm Hg, with septal motion consistent with conduction abnormality.
Coronary angiogram was performed and showed two type A lesions in the right coronary artery (RCA) with TIMI 3 flow. One was proximal and severely stenotic. The second lesion was distal and moderately stenotic. He was also found to have two fistulas draining into the pulmonary trunk and arising bilaterally from the both the RCA and left anterior descending artery (LAD) (Figure 1).
We elected to correct the proximal stenosis with a bare metal stent (BMS) due to concerns for non-compliance and we managed the distal stenosis medically. Right heart catheterization ruled out hemodynamic significance of these fistulas with pulmonary artery pressure (PA): 35/5 mm Hg (normal: 15–30 mm Hg systolic, 2–8 mm Hg diastolic), mean 22 (normal: 9–18 mm Hg), pulmonary capillary wedge pressure (PCWP): 10 mm Hg (normal: 2–15 mm Hg), cardiac output: 5.7 l/min (normal: 4–9 l/min), mixed venous saturation: 68% (normal: 60–80%). Pulmonary vascular resistance: 2.1 (0.25–2.5 mm Hg/l/min) with no “step up” of oxygen saturation from the superior vena cava (SVC) to the...


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