Invited Commentary

High Tech Versus Old School: Will Traditional Craftsmanship Prevail?

This paper by Kappert et al. [1] demonstrates the feasibility of an automated small-vessel anastomosis in a chronic large animal model. The authors can be commended for having performed a thorough and elegant study showing the safety of an ingeniously engineered end-to-side anastomotic device which creates a very natural looking anastomosis and one which does not differ much from a conventional anastomosis in terms of endothelialization and the absence of endoluminal artificial material. Intermediate results show a 100 % patency rate and no significant stenosis. That is, in all respects, a successful and promising trial.

Anastomotic devices have been developed for the purpose of expediting and facilitating procedures in various surgical fields. In the wake of continued improvements of minimally invasive cardiac surgery, the necessity to develop reliable, automated, proximal and subsequently also distal, coronary bypass anastomoses was perceived. An automated proximal anastomosis of a venous graft to the aorta can clearly be considered beneficial in certain scenarios in which side-clamping of the aorta must be avoided because of calcifications or atheromatous plaque burden.

Distal anastomotic devices, however, offer little advantage over conventional, hand-sewn anastomoses apart from uniformity and perhaps slight expedition. Rather, they lack adaptability, which is increasingly important when performing coronary bypass nowadays. As demographic change has gradually shifted CABG surgery away from easy scenarios in young and healthy patients towards more complex patients and concomitant procedures, the coronary surgeon must individualize almost every single anastomosis. Plaques need to be bridged in order to guarantee antegrade as well as retrograde runoff, endarteriectomies and intimal fixation must be carried out, endoluminal stents need to be removed at the very site of the anastomosis, small-caliber arterial grafts or tiny coronary vessels in elderly female patients require very subtle sewing. Size mismatches between graft and target vessel must be dealt with by tailoring. The scarcity of autologous material requires sequential side-to-side anastomosis or y-graft anastomoses. And the vast majority of these measures are performed in patients under anticoagulation with at least one, but often two, platelet aggregation inhibitors.

Even if they were available in several different sizes and lengths, distal coronary anastomotic devices lack this broad range of individual adaptability and will not meet these requirements in the foreseeable future. They are restricted to a minority of patients with proper vessel quality and size. Whether a minimally invasive procedure would be possible in these patients remains questionable. At present, performing an automated distal anastomosis mandatorily requires an additional incision in the coronary artery flanked by a U-shaped suture to allow the anvil of the device to be placed inside the lumen. After completion of the automated anastomoses this hole needs to be closed separately. It is unlikely that all this will result in significant expedition and facilitation.

One must also consider the fact that, despite all the huge efforts in the field of interventional coronary stent grafting, bypass surgery still offers excellent long-term patency rate benefits over PTCA [2]. Even the often derided venous graft offers a primary patency rate of over 70 % after 10 years, thus far exceeding the reported rates for every type of endoluminal stent grafting [3]. Aside from the nature of the graft material itself, this positive outcome is due, not least, to subtle, individualized surgical craftsmanship. Acceptance of even the slightest form of compromise can result in a noticeable decrease in long-term patency as seen in OPCAB surgery [4]. This particularly high achievement, obtained with hand-sewn conventional anastomoses, should therefore not be relinquished lightheartedly by using automated devices which have not yet been proven to offer such exceptionally positive long-term results.

Surgical craftsmanship which offers flexibility in meeting the individual requirements of patients is one of the advantages interventionalists will hardly ever achieve and it should not be jeopardized for just the sake of uniformity.

Finally, costs are important. Even assuming high-volume industrial production, the costs of distal coronary anastomotic devices will remain at around several hundred Euros for a single application, given the complex high precision mechanics involved requiring many different parts, much like a mechanical watch. Performing three or more distal anastomoses would result in marked additional material costs. In the majority of European healthcare systems, however, 90 % of all reimbursements of costs come from the contributions of compulsorily insured patient as well as from public funding. As the overall sums will most certainly remain restricted, hospitals cannot afford to jeopardize the last fields in which there is a substantially positive marginal return, which can be achieved in areas with low material costs such as bypass surgery.

Therefore, I personally do not see automated distal anastomotic devices becoming the device of choice for bypass surgery in any significant numbers in the foreseeable future.

References

• 1 Kappert U, Ouda A, Virmani R, Mettler D, Matschke K, Demertzis S. The C-Port xV® vascular anastomosis system: results from an animal trial.  Thorac Cardiovasc Surg. 2011;  DOI: 10.1055/s-0030-1270959
• 2 Morice M C, Serruys P W, Kappetein A P et al. Outcomes in patients with de novo left main disease treated with either percutaneous coronary intervention using paclitaxel-eluting stents or coronary artery bypass graft treatment in the Synergy between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery (SYNTAX) trial.  Circulation. 2010;  121 (24) 2645-2653
• 3 Tatoulis J, Buxton B F, Fuller J A et al. Long-term patency of 1108 radial arterial-coronary angiograms over 10 years.  Ann Thorac Surg. 2009;  88 (1) 23-29
• 4 Shroyer A L, Grover F L, Hattler B Veterans Affairs Randomized On/Off Bypass (ROOBY) Study Group et al. On-pump versus off-pump coronary-artery bypass surgery.  N Engl J Med. 2009;  361 (19) 1827-1837