SPECIAL CONSIDERATIONS FOR THE ANESTHETIC MANAGEMENT OF BEATING HEART SURGERY

by Luis G. Michelsen, MD
Emory University School
of Medicine, Atlanta, Georgia

Definition of Beating Heart Surgery

Beating heart surgery is characterized by the avoidance of cardiopulmonary bypass (CPB) and includes:

• OPCAB ("Off-Pump" CAB)
• MIDCAB (Minimally Invasive Direct-Vision CAB)

Why Move From Conventional CABG to Beating Heart?

CPB is one of cardiac surgery's most important developments. CPB has made it possible for surgeons to perform coronary revascularization on a still and bloodless heart. This ability has allowed coronary revascularization to become an established procedure that offers tremendous long-term patency rates and low mortality. However, stopping the heart and temporarily replacing its functions with the heart-lung machine has risks associated with it.2,3 Eighty-one percent (81%) of the surgeons polled at the 1997 CTT meeting agreed that the elimination of CPB, rather than reduced incision size, is the most critical issue in reducing the invasiveness of cardiac surgery.4

Factors in the Growth
of Beating Heart Surgery

1. Beating Heart CAB Proven Successful.

Beating heart surgery has been performed for years, particularly in South America, where
economic constraints (oxygenator considered cost-prohibitive) forced the surgeons to perform many cases off-bypass. Bennetti and Buffolo (Argentina and Brazil, respectively) have accumulated a large number of beating heart cases and have shown that not only is it possible to perform beating heart CABG, but it is also possible to perform it effectively and at a reduced cost to the patient.5,6

2. Alternative Care.

Cardiology techniques and therapies (angioplasty, stents and drugs) continue to improve, giving the cardiologist non-surgical alternatives for patient treatment. Surgeons are finding they must compete by offering an improvement on their "best technique"; a left internal mammary artery (LIMA) graft to the left anterior descending coronary artery (LAD). With beating heart surgery they can combine results (long-term patency) with a quicker return of the patient to his normal activities and perhaps even a smaller scar (in the case of MIDCAB).

3. Morbidity of Conventional CABG.

In addition to the morbidity related to myocardial infarction (MI), particularly alarming is the high incidence of neurological dysfunction. The occurrence of strokes and neuropsychological dysfunction are very disabling for the patient and are costly to the healthcare system.

Figure 1. Conventional CABG: Morbidity (MI Ð Myocardial Infarction; CVA Ð cerebrovascular accident; NPD Ð neuropsychological dysfunction; ARF Ð acute renal failure)

 

Advantages to Beating Heart Surgery

There are several advantages to beating heart surgery from the anesthesiologist's perspective:

• The patient is extubated early, is not severely anemic, is awake and breathing on his/her own.
• There are no cannulation sites in large vessels which can potentially bleed.
• Less hemodilution.
• Coagulopathies are uncommon.