Elsevier

The Annals of Thoracic Surgery

Volume 68, Issue 5, November 1999, Pages 1619-1622
The Annals of Thoracic Surgery

Original Articles
Blood flow in composite arterial grafts and effect of native coronary flow

https://doi.org/10.1016/S0003-4975(99)00862-0Get rights and content

Abstract

Background. Total arterial coronary revascularization can be achieved by joining arteries together as a composite graft with the proximal left internal mammary artery as the only source of blood inflow. Proof of the capacity of this composite conduit to provide adequate blood flow to the coronary circulation is required.

Methods. The radial artery was anastomosed to the left internal mammary artery as a Y graft in 17 patients and all coronary arteries grafted. Intraoperative blood flow through the composite grafts was evaluated by the transit-time Doppler technique.

Results. Against no resistance, blood flow in the left internal mammary artery alone was 99 ± 9 mL/min and rose to 173 ± 16 mL/min when the radial artery was anastomosed as a Y graft. Composite-graft flow following grafting was 88 ± 9 mL/min, 49 ± 6 mL/min when the aortic clamp was removed and native coronary flow restored and 82 ± 13 mL/min following weaning from cardiopulmonary bypass. The maximal potential flow through the composite graft was 2.3-fold (95% CI 1.6 to 3.2) greater than that after cardiopulmonary bypass.

Conclusions. Total arterial revascularization, using a composite graft, provided a 2.3-fold reserve of blood flow to the coronary vascular bed through the grafts.

Section snippets

Material and methods

Seventeen patients underwent total arterial coronary revascularization, using a composite graft in which a radial artery was anastomosed to the LIMA near its third intercostal branch [5]. Grafts to all three coronary territories were performed using these two conduits. Sequential anastomoses were constructed as required (Fig 1). In no patients was an aortic anastomosis done, or a vein graft used. The Royal Melbourne Hospital Human Ethics Committee approved the study, and all patients gave

Results

The 17 patients underwent coronary artery bypass operation to all three coronary artery territories. All patients underwent elective operation using a pedicled Y graft technique [5], without concomitant procedures. No patient was excluded based on conduit size or severity of coronary disease. There were 13 men and 4 women. Their mean age was 63 ± 2 years, and mean body surface area was 1.86 ± 0.03 m2. The mean number of distal anastomoses was 3.9 ± 0.2 (range 3 to 5). Mean cardiopulmonary

Comment

In the quest to perform routine total arterial revascularization, composite Y graft methods are gaining popularity 3, 4, 9, 10. All patients in this study had revascularization of all three coronary territories using a composite arterial graft based on the LIMA, which remains attached to the subclavian artery (pedicled). No supplementary grafts were used.

Our data show that construction of a Y graft using RA led to an increase of 74 mL/min in total LIMA pedicle flow (Table 2). The resultant

Acknowledgements

The authors wish to acknowledge Dr John Ludbrook (Biomedical Statistical Consulting Pty Ltd) for his assistance with the statistical analysis and manuscript review and the contribution of Mr James Tatoulis and Prof Duncan W. Blake.

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    Citation Excerpt :

    These results have also been confirmed at all time points of the follow-up. Our data are in agreement with those of Royse and associates [15], who reported an intraoperative 2.3-fold reserve of composite mammary and RA grafts, and with those of Afflek and colleagues [3], who found a flow reserve of 1.6, computed as the ratio of free flow over completion flow, which was considered adequate for flow requirements in the early postoperative period. Lemma and coworkers [4] reported that composite Y-grafts can efficiently adapt to increased flow demand induced by atrial pacing early after operation.

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