Although a more technically demanding procedure to perform, off-pump coronary artery bypass grafting (CABG) resulted in improved perioperative morbidity and mortality compared with CABG using a cardiopulmonary bypass machine.

However, the observed survival advantage for off-pump surgery diminished during the first 5 years of follow-up, according to study results.

John D. Puskas, MD, professor of cardiothoracic surgery at Emory University in Atlanta, presented the findings at the Society of Thoracic Surgeons (STS) 2026 Annual Meeting.

Puskas and fellow researchers examined data from the STS Adult Cardiac Surgery Database on nonemergency isolated CABG between 2008 and 2023. They used the National Death Index and/or Centers for Medicare & Medicaid Services in-patient data through December 2024 to determine long-term survival. 

Only cases of experienced on-pump and off-pump surgeons were included in the analysis. The researchers defined “experienced” using several criteria, including the surgeon contributing at least 200 cases, averaging at least 25 cases per year, and being active for at least 3 years.

All-cause mortality from 0 to 15 years served as the primary endpoint. Mortality from 0 to 5 years and 30-day outcomes were secondary endpoints.

Overall, 205 experienced off-pump CABG surgeons performed 184,655 off-pump cases, whereas 1566 experienced on-pump surgeons performed 1,340,404 on-pump cases. The researchers used propensity matching with a greedy algorithm to form 184,550 very closely matched pairs based on 64 preoperative patient characteristics.

According to Puskas, this number of cases represents the largest long-term follow-up of on-pump and off-pump coronary bypass patients ever performed by a large margin. 

“It has the power to answer the question of whether the long-term benefit of off-pump surgery is as great as the long-term benefit of traditional on-pump surgery,” Puskas told Medscape Medical News.

Off-Pump: Superior Short-Term Outcomes 

Data revealed that incomplete revascularization was more common in the off-pump CABG group (14.4% vs 8.1%; P < .001). These participants received on average 0.20 fewer grafts per patient. Multi-arterial grafting was also increased in off-pump patients (14.5% vs 9.6%; P < .001), resulting in an average of 0.10 more arterial grafts per patient in this cohort.

The researchers reported that the following 30-day outcomes improved in the off-pump CABG group (P for all < .001):

• Operative mortality (1.9% vs 2.2%)
• Stroke (1.1% vs 1.5%)
• New atrial fibrillation (22.4% vs 23.9%)
• Renal failure (2.1% vs 2.6%)
• Return to operating room (1.9% vs 2.5%)
• Prolonged ventilation (6.3% vs 8.7%)
• Any transfusion (45.8% vs 67.6%)

“Off-pump beat on-pump for all of the adverse events in the early days after surgery,” Puskas said. “This [finding] was very significant, in that this is a huge sample size representing the whole country, not just a few select surgeons.” 

The researchers noted that the early off-pump survival advantage steadily diminished over 5 years of follow-up. 

Moreover, patients with one-vessel disease — but not multivessel disease — demonstrated a small off-pump survival advantage through 15 years of follow-up.

Complete Revascularization Is Key 

For Gianluca Torregrossa, MD, director of robotic coronary revascularization at Lankenau Heart Institute in Philadelphia, the key message of the study is that coronary surgery is not defined by pump strategy but by surgeon expertise, completeness of revascularization, and thoughtful use of arterial conduits. 

“A dedicated coronary surgeon tailors the operation to the patient’s anatomy and risk profile rather than forcing the patient into a predefined technique,” said Torregrossa, who was not involved in the research. “In this context, the study also provides a strong scientific rationale for anaortic, multi-arterial, and hybrid robotic strategies that seek to minimize perioperative risk while preserving the long-term durability of arterial revascularization.”

Puskas agreed that complete revascularization is critical in this population. “When performing the surgery off-pump, we should not compromise by performing incomplete revascularization,” he said. “We should completely revascularize every patient, whether their surgery is performed on-pump or off-pump.”

An End to the Debate? 

The new research should represent a summary of the 20-year debate over how to perform the procedure, Torregrossa said. 

“Our cardiac surgical community [needs] to move forward from the off-pump vs on-pump debate,” he said. 

“In the end, off-pump is not worse than on-pump,” he continued. “Off-pump is a high-skill strategy that delivers optimal results in dedicated programs with dedicated surgeons.”

Puskas serves as a consultant for Medtronic. Torregrossa reported no relevant financial disclosures. 

Brian Ellis is a freelance writer and editor who lives in Southwest Virginia.