Business is booming for off-pump bypass surgery. (Better Outcomes or Better Surgeons?).
Today, 25% of U.S. coronary artery bypass graft procedures are performed on beating hearts without use of the cardiopulmonary bypass machine. But there are huge regional differences. In some areas, such as Philadelphia, intense marketing battles between hospitals have intensified the shift to off-pump coronary artery bypass (OPCAB).
"At our own hospital, fundamentally every revascularization starts as an off-pump procedure," said Dr. Wechsler, the Stanley K. Brockman Professor and chairman of cardiothoracic surgery at Drexel University in Philadelphia.
When he asked the Snowmass audience comprised of hundreds of cardiologists how many of them now consider OPCAB to be superior to traditional on-pump CABG, roughly half raised their hands. That, he said, bodes ill for patient recruitment into a definitive randomized trial that's not even at the planning stage.
Surgical adventurers fueled early enthusiasm for OPCAB, which they promoted with messianic zeal as a safer alternative to on-pump CABG. They initially based their case on small observational studies, historic comparisons, and case reports.
Later, large but nonrandomized studies seemed to show important advantages favoring OPCAB. An analysis of 11,717 OPCAB procedures and 106,423 on-pump CABGsf in the Society of Thoracic Surgeons database concluded that mortality in the OPCAB group was 20% less than expected. Total morbidity was 23% less than expected. Morbidity and mortality in the on-pump group were as expected.
And prospective multicenter quality assurance project by the Department of Veterans Affairs concluded that operative mortality in 1,360 OPCAB patients was 34% less than expected. Total morbidity was 36% less than expected. Morbidity and mortality were 10% greater than expected in 3,466 on-pump CABG patients.
The validity of these studies has been questioned as a result of a large study of surgical practice in Texas. The study showed that early adopters of OPCAB quickly grew to rely upon it in about 50% of their cases. A second group took up OPCAB later, used it less often, and ultimately abandoned it. A key finding: Early adopters had lower operative mortality rates for CABG whether the surgery was performed off-pump or on-pump.
This raises doubts about the VA and Society of Thoracic Surgeons studies, Dr. Wechsler said. "Were these really fair comparisons of OPCAB versus on-pump coronary revascularization, or were they in fact looking at very, very skillful surgeons versus just skillful surgeons?"
He is convinced that OPCAB is the more difficult operation and that expert surgeons tended to embrace the procedure first. He also suspects that an adequately powered randomized trial probably would show advantages for OPCAB in older patients, particularly those with organ impairment or severe vascular disease.
"Avoidance of cardiopulmonary bypass in this population is attractive because these patients are so susceptible to potential complications of cardiopulmonary bypass."
But he added that major technologic advances in cardiopulmonary bypass are likely to reduce the machine's sequelae.
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|Publication:||Internal Medicine News|
|Date:||Mar 15, 2003|
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