Ann Thorac Surg 2005;79:1742-1743
© 2005 The Society of Thoracic Surgeons
New technology
INVITED COMMENTARY
Alan P. Kypson, MD,
W. Randolph Chitwood, Jr, MD
Division of Cardiothoracic and Vascular Surgery, Brody School of Medicine, Room 252, East Carolina University, 600 Moye Blvd, Greenville, NC 27858
(E-mail: chitwoodw{at}mail.ecu.edu).
The idea of a mechanically facilitated vascular anastomosis is not new. As early as 1904, Payr [1] devised interlocking magnesium tubes that provided intimal to intimal apposition. Since then, there have been many devices that either failed or rendered suboptimal results. We are always fighting natural vascular biology; that is, endothelial reactivity, intimal hyperplasia, a coagulation cascade, and thrombosis.
As traditional suture methods have become either a rate or access-limiting step during minimally invasive surgery, the need for new anastomotic devices has arisen again. This report from Vicol and colleagues describes the use of magnetic vascular positioners (MVPs) to construct 18 distal anastomoses in 11 patients. Using magnets, this device connects either an artery or vein to a distal coronary target. This is a small, single-center, descriptive study with early angiographic studies (< 30 days) in 10 of the 11 patients. Graft patency was 100%. However, only 72% of distal targets (18 of 25) attempted were achieved with MVP, indicating that target quality influences success.
This study demonstrates how anastomotic devices can facilitate multivessel coronary bypass surgery. In a recent multicenter European MVP trial only 32 (78%) patients were actually treated and each patient had only one anastomosis [2]. Graft patency at one month was 93.5% but was 100% for the 10 internal thoracic artery-to-anterior descending anastomoses. This paper by Vicol and colleagues asks a different question; can the MVP be used effectively during multivessel grafting? This question may not be answered by a small single center study. In this study, the number of distal anastomoses per patient averaged 2.3, low for modern multivessel on-pump operations. There probably was a selection bias toward patients with larger coronaries and without diffuse atherosclerotic disease. Klima and colleagues [2] cited small vessels (< 2 mm) and plaque as limiting MVP. As percutaneous technology has shifted surgical patient selection toward those with more complex vascular pathology, one wonders if these magnetic couplers will evolve to accommodate small, diffusely diseased coronary arteries.
Furthermore, several other concerns arise. First, the requirement for antiplatelet therapy has been shown to increase perioperative bleeding. In the study by Vicol and colleagues, chest tube drainage was high. This will plague surgeons who use anastomotic devices, where areas of blood-exposed nonintimal surface are exposed. Investigators in the European MVP trial also saw increased perioperative bleeding (9%). Second, the quality of angiograms could be a problem. Although patency can be demonstrated with good peripheral runoff, the design makes it impossible to view the actual anastomosis. Clearly, these devices are nondistensible should intimal hyperplasia become a problem, creating difficulties in the long-term interventional management.
The mean time for an MVP anastomosis was 13.5 minutes. Each new procedure has an intrinsic learning curve, taking longer initially than traditional methods. Nevertheless, creation of robotic, closed-chest, suture anastomosis takes even longer. Magnetic couplers may evolve to be the answer for these applications. The authors are to be commended for their contribution to anastomotic technology, for elucidating its weaknesses, and for advancing the dream of totally endoscopic multivessel coronary artery bypass operations.
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References
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- Payr E. Beitrage zur technique der blutgefass-und nervennaht nebst mittheilungen uber die verwendung eines resorbirbaren metalles in de chirurgie Arch Klein Chir 1900;62:67-93.
- Klima U, Falk V, Maringa M, et al. Magnetic vascular coupling for distal anastomoses in coronary bypass graftinga multicenter trial.. J Thorac Cardiovasc Surg 2003;126:1568-1574.[Abstract/Free Full Text]
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