Ann Thorac Surg 1995;59:327
© 1995 The Society of Thoracic Surgeons
Invited Commentary
Invited Commentary
Eric J. Topol, MD
Department of Cardiology Cleveland Clinic Foundation 9500 Euclid Ave Cleveland, OH 44195
See also page 323.
The internal thoracic artery (ITA) clearly has emerged as the conduit of choice for surgical coronary revascularization, offering considerably less attrition over time compared with the saphenous vein graft. Early ITA failure, evidenced by inadequate myocardial blood flow in the first year, is thought to be very low. In a relatively well-circumscribed population, the present study by Najm and colleagues from the University of Ottawa confirms the incidence of early ITA stenosis in approximately 1% of patients. The majority of these patients were identified by symptomatic presentation within 3 months of operation.
The Ottawa experience with balloon angioplasty of the distal ITA anastomosis in 29 patients extends the previous publications of several small series, demonstrating a greater than 90% technical success rate, a very low complication rate, and what appears to be a considerably less restenosis rate than with native coronary artery dilation. A publication bias may exist regarding the high success and low complication rate—at times the ITA lesion can be technically challenging when there is excessive tortuosity. Should a complication of obstructive intimal dissection arise, the management and outcome could be extremely difficult and precarious. Nonetheless, the consensus based on the literature and general experience is that balloon angioplasty works especially well for improving coronary blood flow through the ITA conduit in this setting.
The mechanism for early ITA stenosis remains elusive. Several possibilities are raised by Najm and associates, including the anastomotic technique, narrowing of the pedicle, and myointimal hyperplasia. Although the myointimal hyperplasia after dilation of native coronary artery stenosis usually appears within 3 months, the recurrence rate is much higher than that observed with ITA angioplasty. This suggests that intimal hyperplasia is not the principal cause of the lesion in many patients, and indeed the stenosis may be chiefly related to technical problems—but a suboptimal anastomosis may stimulate intimal hyperplasia such that the etiology may not be truly singular. There are some important parallels to the distal anastomotic lesion of saphenous vein grafts, which, when occurring in the early postoperative setting, also appear to respond well to balloon dilation. Although further efforts to understand the underlying mechanism are important, it is reassuring that early ITA stenosis is a rare event and preservation of this important conduit is quite feasible and durable without resorting to reoperation.
Related Article
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Postoperative Symptomatic Internal Thoracic Artery Stenosis and Successful Treatment With PTCA
- Hani K. Najm, Danielle Leddy, Paul J. Hendry, Jean-Francois Marquis, David Richardson, and Wilbert J. Keon
Ann. Thorac. Surg. 1995 59: 323-326.
[Abstract]
[Full Text]
