Traditional heart surgery is done by diverting the body’s blood circulation away from the heart and lung and the blood is artificially oxygenated and circulated by a heart-lung machine. This technique allows the heart surgeon to stop and work on the heart while the heart-lung machine keeps the vital organs perfused and thus the patient alive. When a heart chamber needs to be opened such as in heart valve surgery, this is obligatory.

However, coronary artery bypass surgery (CABG) is done on the vessels on the surface of the heart and new technology has been developed to allow the surgeons to work on the surface of the heart without stopping it. Therefore, this new technique allows the bypass operation to proceed without the use of the heart-lung machine.

Theoretically, the avoidance of the heart-lung machine may reduce the well known complications in cardiac surgery that maybe attributed to the use of the pump. Thousands of clinical studies and trials worldwide have been conducted over the last decade to determine this possibility.

We have study this extensively on 363 consecutive patients who underwent off-pump and conventional coronary bypass surgery over a one year period (year 2002) done by two surgeons skilled at the new off-pump techniques. Forty-one percent of the cases were done off-pump and the majority of the surgeries were done by one surgeon (Ko). In this study, we found no difference in the hospital mortality (1.3% vs. 0.9%, p-value>0.05) or conversely survival between the two groups.

Similarly, there were no statistical differences between the two groups in the rates of strokes, myocardial infarction, congestive heart failure, respiratory complication, and infection. The off-pump group had slightly and statistically significant lower blood transfusion requirement (less than one unit per patient), shorter length of hospital stays (one day), and slightly better preservation of kidney function in terms of creatinine clearance without any clinical advantage.

We concluded from this study that the off-pump technique provided no significant advantages over the conventional technique of coronary artery bypass surgery for the general population.

The next phase of this venture concentrated on patients who are at high risk of complication from traditional coronary artery bypass surgery. We have known from our numerous studies that the severely diseased aorta is associated with high risk of strokes after conventional CABG, because the aorta is manipulated during much of surgery. We report significant benefits in the absence of strokes or other thromboembolic end organ complication in a group of patients with severely diseased (“porcelain”) aorta by using the off-pump and “no-touch on the aorta” technique.1 In our latest study where 97 consecutive octogenarian patients (all done by one surgeon-Ko) whose advance age is well known to be associated with higher mortality and complications from heart surgery, we demonstrated a significantly lower rates of pulmonary complications (tracheostomy rates: 16% vs. 3%, p-valve<0.02) in the off-pump approach.2 However, even among these extreme elderly patients, we did not find any differences (p-values >0.05) in stroke rates, hospital mortality rates (3.2% vs. 2.7%), or 5 year survival (85% vs. 78%).

In light of our studies which corroborates with a large volume of published literature, our current approach is to perform conventional CABG for the routine cases and reserve the off-pump approach for the patients with conditions that are at risk for a major complication. These indications include the patients with (1) severe cerebrovascular disease or aortic disease that put them at high risk for intraoperative stroke, (2) severe renal insufficiency that is at risk for further deterioration or dialysis, (3) severe lung disease at risk for respiratory failure and tracheotomy, (4) advance liver disease such as cirrhosis in Child’s classification B or C, (5) hematologic disorder3 or on current medications that put them at risk for serious hemorrhage not including Aspirin or Plavix, (6) religious reasons against any homologous blood transfusion, i.e., Jehovah’s Witness.

1. Wilson Ko. Off-Pump Innominate-Coronary Artery Bypass in Patients with Severely Atherosclerotic Ascending Aorta. Heart Surgery Forum. October 2001; #2001-37560. 2. Anita Chiu, Daniel Lee, Wilson Ko. Off-pump versus conventional coronary artery bypass surgery for 97 consecutive octogenarian patients: an analysis of short term outcome and five year survival. Manuscript in preparation. 3. William DeBois, J Liu, Len Lee Len Girardi, Wilson Ko, Anthony Tortolani, Karl Krieger, O. Wayne Isom. Cardiopulmonary bypass in patients with pre-existing coagulopathy. J Extra Corpor Technol. 2005 Mar;37(1):15-22. Review.

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