Assessment of the hemodynamic significance of a left internal mammary artery graft-pulmonary artery shunt in a post-bypass patient using a Doppler-tipped guide wire.

We assessed the hemodynamic significance of a left internal mammary artery (LIMA) graft-pulmonary artery (PA) fistula in a post-bypass patient with chest pain. A Doppler-tipped guide wire and quantitative coronary angiography (QCA) were used to demonstrate that flow through the proximal LIMA (14.0 ml/min) was similar to the distal LIMA's contribution of flow to the left anterior descending artery (LAD) (15.6 ml/min), suggesting that the fistula was not hemodynamically significant. Therefore, intravascular Doppler and quantitative angiography may be used to assess the hemodynamic significance of a LIMA-PA fistula in a post-bypass patient.