Cardiovascular Disease and Risk Factors Increasing Among Patients Undergoing Noncardiac Surgery

The average burden of cardiovascular risk and the prevalence of atherosclerotic cardiovascular disease (ASCVD) among adult patients undergoing noncardiac surgery in the United States have been creeping higher and higher, new data show.

This has implications for the more than 300 million people undergoing noncardiac surgery worldwide every year, according to lead author Nathaniel Smilowitz, MD (New York University School of Medicine, NY), and colleagues. “Major cardiovascular and cerebrovascular complications, including death, myocardial infarction or stroke, occur in approximately one of every 33 hospitalizations for noncardiac surgery,” they write.

Using data from the US Nationwide Inpatient Sample, the researchers reviewed more than 10 million hospitalizations of adults aged at least 45 years for major noncardiac surgery between 2004 and 2013. Their results were published online January 5, 2018, ahead of print in Heart.

Between 2008 and 2013, nearly one in four patients undergoing noncardiac surgery also had some kind of ASCVD diagnosis and at least one cardiovascular risk factor was seen in nearly 75% of patients.

Comparing patients undergoing surgery between 2008 and 2009 with those treated between 2012 and 2013, the proportion of patients with two or more cardiovascular risk factors increased from 40.5% to 48.2%, while a history of prior stroke rose from 3.5% to 4.7% (P < 0.001 for both). The numbers are equally striking over a longer period. Between 2004-2005 and 2012-2013, the prevalence of CAD (17.2% vs 18.2%) and PAD (6.3% vs. 7.4%) both increased significantly (P < 0.001). Lastly, the proportion of patients with a modified Revised Cardiac Risk Index score of 3 or greater—pointing to high perioperative cardiovascular risk—increased from 6.6% to 7.7% between 2008-2009 and 2012-2013 (P < 0.001).

Of note, the risk factors dyslipidemia and obesity doubled from 18.8% to 36.6% and 7.2% to 15.2%, respectively. Mean patient age remained stable over the study period.

“The increasing prevalence of risk factors and cardiovascular disease in the present analysis may be partially explained by recent trends towards outpatient ambulatory surgical procedures for the healthiest surgical candidates, thereby increasing cardiovascular risk profiles of hospitalized surgical patients over time,” Smilowitz and colleagues write. “Still, the trends observed in the present analysis appear to be consistent with those described among the adult population at large.”

Research from the same group published last year using the same national cohort found that perioperative major adverse cardiac events decreased from 3.1% to 2.6% between 2004 and 2013, a “surprising” finding they now say. While the mechanism behind this drop is “uncertain,” the researchers continue, improvements in medical management through antiplatelet therapy and statins, less invasive surgical approaches, better anesthesia care and hemodynamic management, and advances in postoperative care could be related.

A Shifting Population

Commenting to TCTMD, P.J. Devereaux, MD, PhD (Population Health Research Institute, Hamilton, Canada), said the study highlights the fact that “we’re basically doing surgery on older and sicker patients and the patient population having surgery [is] moving toward higher and higher burdens of cardiovascular disease.”

Clinicians shouldn’t “lose sight of the fact that people are having surgery for very important reasons,” he continued, but “at the same time, surgery does create a substantial stress that can lead to significant complications.” Moving forward, these findings only strengthen the need for additional research on how to prevent and better manage cardiovascular complications in a changing population of surgical patients, Devereaux stressed.

We’re basically doing surgery on older and sicker patients, and the patient population having surgery [is] moving toward higher and higher burdens of cardiovascular disease. P.J. Devereaux

Previous research has shown that when clinicians fail to measure cardiac biomarkers in patients after noncardiac surgery, “you will miss about two-thirds of people that have a heart attack and you miss about 90% of the people who have a heart injury,” he said. “The reason for that is that most of the heart attacks and heart injuries happen in the first 24-36 hours after surgery, and it's when everyone is getting narcotics to blunt surgical discomfort.”

Since many centers do not routinely take these measurements, there remains “an underestimation of the actual true negative impact that's happening to some of these patients,” Devereaux continued, although these patterns may be “shifting.”

For now, he said, clinicians need to recognize that surgical patients are becoming older and sicker. “People within medicine and cardiology need to start playing a more active role to help figure out a way to ensure that these patients do well from a cardiovascular point of view, because that's one of the biggest risks to these patients when they have surgery,” Devereaux concluded.