Objectives: Composite Y-grafts, using the left internal thoracic artery (ITA) as the inflow, allow a more efficient use of conduits without the need to touch a diseased ascending aorta. Among other conduits, the saphenous vein graft (SVG) may be an alternative to the radial artery in elderly patients.
Methods: We evaluated the hemodynamic characteristics of 17 composite Y-grafts made with the left ITA anastomosed to the LAD in all cases and with either the free right ITA (n=10) or a SVG (n=7) implanted proximally to the left ITA and distally to the circumflex territory 6 months after surgery.
Results: At baseline, the pressure gradient measured with a 0.014-inch pressure-wire was minimal between the aorta and the ITA-stem (2±1 mmHg), the ITA-LAD (4±2 mmHg), the ITA-LCX (3±1 mmHg) and the SVG-LCX (2±2 mmHg). During an hyperemia induced by adenosine, the pressure gradient increased significantly to 6±2 mmHg in the ITA-stem, 9±4 mmHg in the ITA-LAD, 9±3 mmHg in the ITA-LCX and 7±4 mmHg in the SVG-LCX. Fractional flow reserve was 0.94 ± 0.02 in ITA-stem, 0.90±0.04 mmHg in the ITA-LAD, 0.91±0.03 mmHg in the ITA-LCX and 0.92±0.06 mmHg in the SVG-LCX. No difference between the two types of composite Y-grafts was observed for pressure gradients or FFR measured in ITA-stem or in distal branches.
Conclusions: Composite Y-grafts with saphenous vein or right internal thoracic arteries allow similar and adequate reperfusion of the left system with minimal resistance to maximal flow and an even distribution of flow in both distal branches.