High-Risk Cardiovascular Surgeries Show Long-term Survival Gains

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Operative mortality for coronary artery bypass grafting (CABG), carotid endarterectomy (CEA), aortic valve replacement, and abdominal aortic aneurysm (AAA) repair has dropped sharply in recent years, according to a decade-long look at high-risk surgeries published in the June 2, 2011, issue of the New England Journal of Medicine. Interestingly, the paper notes, only some of that improvement appears to stem from higher hospital volumes.

Jonathan F. Finks, MD, and colleagues at the University of Michigan (Ann Arbor, MI), gathered information from the Medicare Provider Analysis and Review database, which contains all hospital discharge abstracts for fee-for-service, acute care hospitalizations for Medicare recipients nationwide. Procedure codes were used to identify all patients aged 65 to 99 years who underwent 1 of 8 high-risk cancer and cardiovascular operations between 1999 and 2008. The surgeries included:

• Esophagectomy
• Pancreatectomy
• Lung resection
• Cystectomy
• AAA repair (including both surgical and percutaneous procedures, which shared codes during some of the study period)
• CABG
• CEA
• Aortic valve replacement

In all, 3.2 million Medicare patients underwent 1 of the relevant surgeries during the 10-year study period. Median hospital volumes rose for both AAA repair and aortic-valve replacement but decreased for CABG and CEA (table 1).

Table 1. Treatment Trends: 1999-2008

^a Cases/hospital/year.

The reasons for shifts in hospital volume varied, the paper notes. For aortic valve replacement, the uptick could be attributed simply to an increase in the number of procedures. However, hospital volumes for AAA repair rose due to a decrease in the number of hospitals performing the procedure as well as an increase in the number of patients. Both endarterectomy and CABG were less commonly performed, possibly because of a rise in percutaneous alternatives. In addition, more hospitals began to offer CABG, either because of financial incentives or to supply surgical backup to PCI.

Risk-adjusted operative mortality rates declined for all of the cardiovascular procedures considered (table 2).

Table 2. Operative Mortality: 1999-2008

Only a small proportion of the mortality decrease could be attributed to increasing hospital volume for AAA repair (11%) and aortic-valve replacement (9%), whereas volume played no part in improved survival for CABG and endarterectomy patients. According to the paper, “direct associations between hospital volume and outcome are considerably weaker” for cardiovascular procedures compared with the other high-risk surgeries considered.

Volume Doesn’t Explain It All

“The fact that mortality for all 8 procedures declined during the 10-year study period suggests that there are factors common to all these procedures that contributed to mortality reduction,” the investigators note.

In a telephone interview with TCTMD, Dr. Finks said that the “overall take-home message from this study is that in the United States, complex surgery has become safer over the last decade. That’s true for the cancer operations as well as for the cardiovascular procedures.”

For the latter, however, neither higher hospital volume nor market concentration—a steady number of patients being shared by a smaller number of higher-volume hospitals—appeared totally responsible for the improvement, he noted. “Clearly other factors are at work here.”

“In cardiovascular surgery, in particular, there have been several quality improvement measures over the past decade that have really contributed to improvements in mortality,” Dr. Fink commented, mentioning the large national database maintained by the Society of Thoracic Surgeons as well as regional efforts. “[A]cross the board, ever since the Institute of Medicine’s 1999 report on preventable medical errors, there has been an emphasis among hospitals and surgeons to focus on patient safety,” he said.

Improved communication in the operating room, better intensive care unit staffing, and the use of checklists have all been instrumental, Dr. Fink added.

In addition, “pay-for-performance programs and other efforts by payers to improve hospital compliance with evidence-based practices related to perioperative care may have contributed to improvements in surgical outcomes,” the paper notes. “Since most such programs have been implemented only recently, however, they cannot explain improvements in mortality starting more than 10 years ago.”

 

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Source:
Finks JF, Osborne NH, Birkmeyer JD. Trends in hospital volume and operative mortality for high-risk surgery. N Engl J Med. 2011;364:2128-2137.

 

 

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