Disparities in treatment improve, except for women
An analysis of 12 million revascularization procedures from the Nationwide Inpatient Sample database documented a 40% decrease in coronary artery bypass graft (CABG) surgery volume and a 43% decrease in percutaneous coronary intervention (PCI) volume between 2003 and 2016.
The biggest drops in volume occurred early and appeared to stabilize at approximately 200,000 CABG procedures annually and 450,000 PCIs annually, although CABG volume reached a steady level earlier than PCI volume (2010 vs. 2014).
The reasons for the substantial decrease in both PCI and CABG are only speculative, but the investigators of a study published in JAMA Network Open suggest that the decrease may reflect changes in the management of stable coronary artery disease (CAD) after landmark trials demonstrated the effectiveness of medical management of the disease. Supporting this notion was the increasing proportion of patients with acute myocardial infarction (AMI) seen over time among all patients undergoing PCI (from 22.8% to 53.1%) and CABG (from 19.6% to 28.2%).
One of the biggest surprises: despite countless papers on the disparities between the treatment of male and female patients in medicine, not only did women remain underrepresented (approximately one-third of revascularization patients overall), their proportion decreased over time in both the CABG cohort (dropping from 29.0% in 2003-2006 to 26.0% in 2012-2016; p < 0.001) and PCI cohort (34.0% to 32.8% for the same periods; p < 0.001).
The study’s first author, Mohamad Alkhouli, MD, of the Mayo Clinic School of Medicine, Rochester, Minnesota, called the finding “a major observation.” He told CRTOnline that while the type of databases used in this study (administrative) do not allow full assessment of the etiology of such a disparity, “it’s likely multifactorial and related to differences in the incidence, recognition, presentation, referral, offering, acceptance, and outcomes of both PCI and CABG in men and women.”
What was worrisome, though, he added, was that the disparity between men and women worsened over time.
“This calls for more research,” Alkhouli said, “to identify the reasons for this disparity and strategies for its mitigation.”
The increased proportion of patients with AMI undergoing coronary revascularization was just one indicator of the shifting patient population, as was the marked increase in the prevalence of clinical risk factors.
This was a global finding that included standard atherosclerotic risk factors (e.g., hypertension, hyperlipidemia, and diabetes), nonatherosclerotic risk factors (e.g., lung, renal, and liver disease), and concomitant non-coronary atherosclerosis (e.g., carotid stenosis and vascular disease).
In the PCI cohort, there was an increasing number of particularly high-risk patients (e.g., those with cardiogenic shock and chronic total occlusions) but fewer multivessel PCIs. On the CABG side, there were fewer multivessel (>2) CABGs, and fewer off-pump CABGs, but greater use of arterial conduits.
Alkhouli and colleagues also found significant changes in the demographic characteristics, socioeconomic status, and clinical presentation of patients. There was an increase in the proportion of elderly patients (>85 years old), male patients, patients from racial minorities, and those with lower income.
Over the study period, in-hospital mortality decreased with CABG, but not for PCI. Both crude and risk-adjusted CABG mortality decreased significantly over time despite the substantial drop in annual volume and the increasing prevalence of higher-risk patients.
Crude in-hospital mortality for PCI increased over the study period, but after risk adjustment, in-hospital mortality with PCI increased but only modestly, with the biggest increase seen after PCI for STEMI (4.9% to 5.3%; p < 0.001 for trend).
That seems counterintuitive given all the advances in PCI in recent years, including improvements in drug-eluting stents, radial access, mechanical circulatory support, and door-to-balloon time.
Alkhouli noted that offsetting these enhancements in tools and technique may be the fact that patients referred for PCI are increasingly sicker and more complex. Plus, with a deep drop in the volume of revascularization, there may be a decrease in operator experience. While this drop in volume would theoretically apply to both CABG and PCI, the authors speculate that its association with outcomes might be greater with PCI because of the larger number of PCI operators.
“I think these data provide a big picture snapshot of coronary revascularization in the US and how it changed over time,” Alkhouli said. “It would be interesting to repeat the same analysis in a few years to see the impact of the new landmark trials, like EXCEL, NOBLE, and ISCHEMIA.”
Alkhouli M, Alqahtani F, Kalra A, et al. Trends in Characteristics and Outcomes of Patients Undergoing Coronary Revascularization in the United States, 2003-2016. JAMA Network Open 2020;3(2):e1921326. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2760898