COLORADO SPRINGS – With bundled payment models for coronary artery bypass graft surgery looming ahead, it’s vital that cardiac surgeons take a hard look at the procedure’s hidden costs – namely, the steep price tag for postoperative complications, James H. Mehaffey, MD, said at the annual meeting of the Western Thoracic Surgical Association.

He presented a retrospective study of the 30-day hospital costs for all 36,588 patients who underwent isolated CABG during 2006-2015 at the 19 Virginia centers where the surgery is performed. This was a typical CABG population, with an average predicted risk of mortality of 1.9%. The actual 30-day mortality was 0.6%, so the surgical performance was better than expected.

A complication-free CABG was experienced by 67.7% of the Virginia patients, and it cost an average of $36,580. A minor complication boosted the average cost of a CABG by nearly $2,000. And a major complication as defined by the Society of Thoracic Surgeons sent costs through the roof.

“The population of patients experiencing one or more major comorbidities demonstrated a significant and dramatic increase in total hospital costs. It was an exponential increase with each additional major morbidity,” reported Dr. Mehaffey of the University of Virginia, Charlottesville.

Indeed, the average cost jumped from $36,580 for uncomplicated surgery to $64,542 with one major complication, $111,239 with two, and $194,043 with three.

The two most frequent major complications were postoperative atrial fibrillation, which occurred in 18.4% of patients, and prolonged ventilation for longer than 24 hours, which occurred in 9%. Over the course of the decade-long study period, the 19 medical centers in the Virginia Cardiac Surgery Quality Initiative collectively spent roughly $59 million on prolonged ventilation and $27 million for postoperative atrial fibrillation.

The cost of CABG during the study years outpaced the CMS health care–specific inflation rate, and this escalating cost was driven primarily by postoperative complications.

For the Virginia cardiac surgery collaborative, these data on the cost of postoperative complications will be utilized to prioritize quality improvement projects.

“There are a million different quality initiatives we could take on, all sorts of things we could do, but when you have to decide what to tackle next, I think you have to look at where the financial burden is coming from,” said Dr. Mehaffey.

For example, during the past decade, the Virginia collaborative made reduction in the rate of postoperative atrial fibrillation a priority. Toward that end, the collaborative developed a protocol for routine perioperative prophylactic amiodarone therapy.

“At the beginning of the study decade we had postoperative atrial fibrillation rates above 25%. The average for the entire decade was just over 18%, and in the last couple years we’ve been in the 15%-16% range. So I think we are moving the needle on this. We are making a meaningful impact,” Dr. Mehaffey said.

“We’ve already used the complication cost data to do a cost-effectiveness analysis of our prophylactic amiodarone innovation. We showed we saved an average of $250 per patient, even though we’re treating a bunch of patients who’d never get that complication,” he continued.

This sort of data on the cost of adverse events is also critical to accurately risk-adjust bundled payment models.

Discussant Richard J. Shemin, MD, asked if there was much variability in postoperative complication costs between the CABG centers in the Virginia collaborative.

The variability is enormous, Dr. Mehaffey replied. Investigators recently plugged the last 5 years worth of hospital cost and complication rate data into a proposed CABG bundled payment model and extrapolated what that would mean over the next 5 years.

“There were some institutions that would be positive by a couple million dollars from this payment system and some that were losing more than $20 million, just because of the cost variability,” said Dr. Mehaffey.

Dr. Shemin also noted that the Virginia collaborative was able to collect 30-day outcome data only through the STS database, yet the bundled payment programs are based on the 90-day postoperative experience.

“How do we capture the costs in that full 90 days that we’ll be responsible for?” asked Dr. Shemin, professor of surgery and codirector of the UCLA Cardiovascular Center.

Dr. Mehaffey said that’s indeed an important question, since a major complication such as stroke or deep sternal wound infection typically entails considerable long-term costs and repeated hospital admissions beyond the 30-day window. In Virginia, the cardiac surgery collaborative is working with payers to gain access to the 90 days worth of patient data.

He reported having no financial conflicts regarding his study.

bjancin@frontlinemedcom.com

Hidden CABG costs will disrupt bundled payment systems