30-Day Mortality Spike After Heart Surgery ‘Potentially Troubling’

Analyzing a national database of hospital inpatient records, a team of researchers reports an expected spike in mortality six days after cardiac surgery, but also a more surprising and potentially troubling jump in deaths at the 30-day mark.


Analyzing a national database of hospital inpatient records, a team of researchers reports an expected spike in mortality six days after cardiac surgery, but also a more surprising and potentially troubling jump in deaths at the 30-day mark.

They suggest that while there could be “organic” medical reasons for the extra deaths, the more likely explanation may be an unintended consequence of putting so much emphasis on marking one-month “survival” as a key measurement of surgical success.

“One possibility for the spike is that by often measuring survival at 30 days, such quality improvement metrics may be inadvertently influencing the timing of end-of-life decision-making and withdrawal of aggressive treatment,” says Johns Hopkins Medicine anesthesiologist Bryan G. Maxwell, M.D., who led the research that was conducted when he was a fellow at Stanford University.

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For the study, Maxwell and his team analyzed data from over 595,000 heart surgery admissions — primarily for cardiac bypass or valve surgery — between 2005 and 2009 in a federal database known as the Nationwide Inpatient Sample. Overall, 19,454 patients (3.27 percent) died in the hospital.

After heart surgery, Maxwell says, a certain percentage of patients will die in the first few days or week, and the early increases in hospital mortality seen in their analysis likely reflect the fact that patients who are going to do well have already been discharged, leaving behind the sickest and most complicated cases.

But in a report published online in the journal Health Services Research, he and his colleagues say they can find no similar “organic” explanation for the spike in deaths at day 30, the most common outcome measure used nationally to assess the postoperative course of cardiac surgery patients in a given hospital. “We observed these shifts in the pattern of mortality, and we don’t have any good medical explanation for them,” Maxwell said. “But they raise the possibility that when there’s a motivation to get to that 30-day mark, the very act of measuring may lead to more aggressive treatment behaviors.”

He fears the common but somewhat arbitrary use of 30-day survival as a benchmark of surgical “success” rates may be leading to delays in facing inevitable deaths, increased patient and family discomfort, and unnecessary days in intensive care units.

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