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OBJECTIVE: Bilateral internal thoracic artery (BITA) grafting provides improved graft patency and potential survival advantage in selected patients as compared to single left internal thoracic artery (LITA) revascularization. The ideal functional BITA configuration remains controversial.
METHODS: Patients undergoing planned BITA revascularization with greater than 75% stenosis in both the left anterior descending artery and in a circumflex branch were prospectively randomized to one of two proximal free RITA connections: directly off of the aorta (Ao) (n=13) or as a “t” graft off the LITA (t) (n=12). The LITA was placed to the LAD in all cases and the RITA was placed to a single lateral wall vessel. No sequential arterial grafts were performed and saphenous veins were used for all additional grafts. Intra-operative transit time flow measurements of all arterial grafts was performed and RITA fractional flow parameters were compared between the 2 groups.
RESULTS: There were no differences in pre-operative LVEF (Ao=49.5±8.6, t=58.3±7.8, p=0.02), mean age (Ao=60.7±8.1, t=66.3±7.5, p=0.1), diabetes (Ao=6, t=6, p=1), COPD(Ao=2, t=3, p=0.7), peripheral vascular disease(Ao=1, t=0, p=1), calculated NYSTS risk(Ao=0.01±0.01, t=0.01±0.005, p=0.6), or number of distal anastomoses (Ao=3.16±0.57, t=3.16±0.57, p=1). The Ao group demonstrated significantly higher RITA fractional flow (Ao=0.52±0.14, t=0.36±0.11, p=0.01) and RITA fractional flow/pressure (Ao=0.43±0.16, t=0.27±0.11, p=0.01) than the “t” grafted patients. Graft quality was equivalent amongst groups as no differences in RITA or LITA diastolic filling and pulsatility indices were detected. Thirty day mortality and wound infection was 0% for each group. Conclusions: Acute flow measurements indicate that the free RIMA anastomosed to the aorta provides more acute fractional RITA flow than composite “t” grafting to the LITA. Longer-term angiographic and clinical follow-up of these two groups remains to be defined.
CONCLUSIONS: Acute flow measurements indicate that the free RIMA anastomosed to the aorta provides more acute fractional RITA flow than composite “t” grafting to the LITA. Longer-term angiographic and clinical follow-up of these two groups remains to be defined.

Hemodynamics measurements in LIMA and RIMA

Variable	Off aorta	T configuration	P value
LIMA mean flow	36.1±18	41.2±16	0.48
LIMA DF	74.7±5	68.5±10.3	0.1
RIMA mean flow	37.1±13.6	22.1±9.5	0.008
RIMA DF	61.5±11.7	65.9±5.6	0.3
T mean flow		82.7±10.4
LIMA conductance	0.42±0.21	0.52±0.19	0.2
RIMA conductance	0.44±0.16	0.28±0.11	0.01
LIMA fractional flow	0.48±0.15	0.64±0.11	0.01
RIMA fractional flow	0.52±0.15	0.36±0.11	0.01