Ann Thorac Surg 2006;82:68
© 2006 The Society of Thoracic Surgeons
Original article: Cardiovascular
Invited commentary
Johannes M. Albes, MD, PhD
Department of Cardiothoracic and Vascular Surgery, Heart Center Brandenburg, Ladeburger Strasse 17, Bernau, Germany 16321
(Email: j.albes{at}immanuel.de).
Off-pump coronary artery bypass (OPCAB) surgery has become an accepted clinical modality ever since it was reinaugurated by Benetti in 1985 [1]. However, in a rather arduous evolutionary process, exposition maneuvers were constantly refined during the years. Dislocation strategies with vacuum stabilizers (particularly for the apex as well as smartly positioned stay-sutures) have greatly improved access to the lateral and inferior wall. At present, repositioning and dislocation maneuvers are considered to be a nuisance rather than a challenge for the experienced off-pump surgeon. However, there may be more to it than meets the eye. Cardiac dislocation may in fact endanger the patient.
Fiore and colleagues [2] can be commended on aiming at a clear and simple target in the clinical setting by means of a clear and simple method (ie, assessment of mesenteric blood flow changes with transesophageal echocardiography during cardiac dislocation maneuvers in OPCAB surgery to elucidate potentially adverse effects). They did indeed prove that dislocation of the heart for the purpose of exposing the inferior or lateral coronary vessels resulted in a sharp and significant decrease of mesenteric blood flow despite the anesthesiologist's efforts to counterbalance hemodynamic changes. Prolonged decrease of cardiac output accompanied by an increase in venous pressure as shown in Fiore and colleagues' [2] study can do considerable harm. Not only may the intestine suffer from hypoperfusion, renal blood flow may also be impeded turning the scale toward renal failure in already affected patients. Future studies may help to provide a safety margin regarding the period of cardiac dislocation maneuvers. Meanwhile the prudent surgeon may release the heart as often as possible to limit splanchnic hypoperfusion to an unavoidable minimum while the anesthesiologist simultaneously verifies proper mesenteric blood flow by means of transesophageal echocardiography.
Off-pump coronary artery bypass revascularization belongs to the armamentarium of contemporary coronary surgery. However it is not the "philosopher's stone" and will not replace conventional means as the current numbers indicate anyway. Benetti [1] has stated that only a minority of his patients may be eligible for OPCAB surgery. That statement is 20 years old, but it is as fresh as ever.
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References
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- Benetti FJ. Direct coronary surgery with saphenous vein bypass without either cardiopulmonary bypass or cardiac arrest J Cardiovasc Surg (Torino) 1985;26(3):217-222.[Medline]
- Fiore G, Brienza N, Cicala P, et al. Superior mesenteric artery blood flow modifications during off-pump coronary surgery Ann Thorac Surg 2006;82:62-68.[Abstract/Free Full Text]
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