Eur J Cardiothorac Surg 2001;19:543-544
© 2001 Elsevier Science NL
Reply to Alverez
Alistair Royse
Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
Received 12 January 2000;
accepted 2 January 2001.
Tel./fax: +61-3-9435-4746
e-mail: a1istair.royse{at}mh.org.au
Dr Alverez claims that our own results show that the left internal mammary artery (LIMA) used as a composite graft to the left anterior descending (LAD) territory arteries has a higher failure rate than non composite IMA [1]. He does not appear to understand that composite IMA was grafted to the LAD territory arteries of mild or moderate stenosis more frequently than non-composite IMA. Since the degree of coronary stenosis was the most powerful predictor of patency, these two groups are therefore not directly comparable. Though long term studies are required, our short-term study strongly suggests that Dr Alverez may be in error.
Arterial conduit was anastomosed to the LAD territory 174 times, Table 1. Of 89 anastomoses from composite IMA there were ten string signs in eight patients, and from non-composite IMA there were 80 anastomoses with no string signs. Indication for grafting was, moderate left main coronary stenosis with normal LAD; moderate LAD stenosis in the setting of triple vessel coronary disease; and ‘crossing’ a distal LAD stenosis with the anastomosis resulting in minimal residual LAD stenosis. All but one of these string sign conduits were grafted to LAD stenoses 
60%. Patency was 100% where coronary stenosis was 
80% and all radial artery (RA) grafts were patent, irrespective of composite origin or coronary stenosis. These data compare favourably with historical studies where grafting would generally have been restricted to coronary arteries of stenosis 80%. This supports the findings of the original paper that the most important influence on patency was the degree of coronary stenosis to which a graft is competing.
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Table 1. Patency of arterial graft anastomoses to the left anterior descending artery territory versus degree of coronary artery stenosisa
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These eight patients were followed up for the purposes of this reply at 43.6±11.6 months postoperative. Four had further angiograms subsequent to the original paper so that angiographic follow up for all eight patients is 24.3±7.9 months. There were no new findings. Seven patients remained asymptomatic and six of these had undergone sestamibi nuclear exercise tests prior to the original paper, all negative. One of these later developed angina related to progression of native coronary disease affecting an ungrafted second marginal artery and underwent successful percutaneous angioplasty and stent (PTCA) and remains asymptomatic. The only symptomatic patient with an LAD stenosis of 75%, continued to complain of pain which was considered variably as musculoskeletal, or angina. A sestambi study revealed mildly reversible ischaemia in the non-LAD territory. There was also a RA string sign to a moderately stenosed posterior descending artery and an ungrafted, small and diseased left ventricular branch artery and distal marginal artery. Most recent angiography at 32.6 months postoperative revealed no change and PTCA to the LAD was performed at 33.0 months, without resolution of symptoms. Therefore, no patient with a LIMA string sign to the LAD territory had symptoms related to ischaemia in this territory; and none of these patients had adverse outcome. The operative mortality of this technique is low [2–4].
References
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Royse A.G., Royse C.F., Tatoulis J., Grigg L.E., Shah P., Hunt D., Better N., Marasco S.F. Postoperative radial artery angiography for coronary artery bypass surgery. Eur J Cardio-thorac Surg 2000;17:294-304.[Abstract/Free Full Text]
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Royse A.G., Royse C.F., Raman J.S. Exclusive Y graft operation for multivessel coronary revascularization. Ann Thorac Surg 1999;68:1612-1618.[Abstract/Free Full Text]
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Sundt T.M., 3rd, Barner H.B., Camillo C.J., Gay W.A., Jr Total arterial revasculanzation with an internal thoracic artery and radial artery T graft. Ann Thorac Surg 1999;68:399-404.[Abstract/Free Full Text]
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Wendler O., Hennen B., Markwirth T., Konig J., Tscholl D., Huang Q., Shahangi E., Schafers H.J., Borst S.H. T grafts with the right internal thoracic artery to left internal thoracic artery versus the left internal thoracic artery and radial artery: flow dynamics in the internal thoracic artery main stem. J Thorac Cardiovasc Surg 1999;118:841-848.[Abstract/Free Full Text]
