Coronary stenosis and steal phenomenon in coronary-pulmonary fistula--assessment with stress thallium tomography after coronary angioplasty and fistulectomy.

We present a 46-year-old male with unstable angina and bilateral coronary-to-pulmonary artery fistulae in whom reversible myocardial ischemia was detected by exercise-stress thallium-201 single-photon emission computed tomography (SPECT). Coronary angiography revealed a 99% stenosis at the proximal site of the left descending coronary artery and bilateral coronary-to-pulmonary artery fistulae with a saccular aneurysm. Percutaneous transluminal coronary angioplasty abolished chest pain and electrocardiographic changes. However, definitely improved, but still present, stress-induced perfusion abnormalities were demonstrated by an exercise-stress thallium-201 SPECT study. Myocardial ischemia was the only serious complication related to the coronary fistulae, and after they were surgically resected, the reversible perfusion abnormality was no longer observed. These findings suggest that coronary-to-pulmonary artery fistulae potentiated the myocardial ischemia in patient with coronary stenosis leading to unstable angina and prolonged the presence of coronary perfusion abnormality on stress thallium scans probably through a coronary steal phenomenon.