Post-stent implantation: Poorly apposed stent struts visible with OCT Image source: Massachusetts General Hospital in Boston/LightLab Imaging

In an examination of the appropriateness of the widespread use of PCIs, researchers found that of more than 500,000 PCIs, nearly all for acute indications were classified as appropriate, whereas only about half of PCIs performed for non-acute indications could be classified as appropriate, according to a study published July 6 in the Journal of the American Medical Association.

Approximately 600,000 PCIs are performed in the U.S. each year, at a cost that exceeds $12 billion. Patients who undergo PCI are exposed to risks of peri-procedural complications and longer-term bleeding and stent thrombosis, according the study. "Moreover, recent trials in stable patients without acute coronary syndromes have shown that PCI, compared with medical therapy, may provide only a modest population-average improvement in symptom relief,” the researchers wrote. "Given the cost and invasiveness of PCI, determining the extent to which PCI procedures are performed for appropriate and inappropriate indications could identify procedural overuse and areas for quality improvement and cost savings.”

Recently, appropriate use criteria for coronary revascularization were jointly developed by six professional organizations to support the rational and judicious use of PCI. 

Paul S. Chan, MD, of Saint Luke's Mid America Heart and Vascular Institute in Kansas City, Mo., and colleagues conducted a study to quantify the proportion of PCIs classified as appropriate, of uncertain appropriateness, and as inappropriate for acute as well as non-acute indications. The study included data from patients within the National Cardiovascular Data Registry undergoing PCI between July 2009 and September 2010 at 1,091 U.S. hospitals.

The appropriateness of PCI was determined using the appropriate use criteria for coronary revascularization. Results were stratified by whether the procedure was performed for acute indication (for STEMI patients) or non-acute indication. 

Of 500,154 procedures classified, 20.6 percent were for STEMI, 21.1 percent for non-STEMI, 29.3 percent for high-risk unstable angina and 28.9 percent for non-acute elective indications. Based on the appropriate use criteria definition for acute procedures, 71.1 percent of the PCIs were for acute indications and 28.9 percent were for non-acute indications.

Chan et al reported that heart attacks comprised 58.8 percent of all acute procedures, while high-risk unstable angina comprised 41.2 percent.

The researchers found that 98.6 percent of acute PCIs were classified as appropriate, with 0.3 percent classified as uncertain and 1.1 percent as inappropriate. Overall, 50.4 percent of non-acute PCIs were classified as appropriate, while 38 percent were for uncertain indications and 11.6 percent were for inappropriate indications.

In general, compared with procedures classified as appropriate and uncertain, inappropriate PCIs were more likely to occur in patients with no angina, low-risk non-invasive stress testing results or suboptimal anti-anginal therapy. 

There was substantial hospital-level variation in the proportion of inappropriate procedures for non-acute indications, Chan and colleagues reported. Hospitals in the lowest quartile had rates of inappropriate PCI of 6 percent or lower, while the rate of inappropriate PCI was greater than 16 percent among hospitals in the highest quartile. Analysis of the data suggested an 80 percent greater likelihood of patients with identical clinical characteristics receiving an inappropriate PCI at one randomly selected hospital as compared with another.

As a limitation, the researchers noted that not all hospitals that perform PCI in the U.S. participate in the NCDR CathPCI Registry.

“Collectively, these findings suggest an important opportunity to examine and improve the selection of patients undergoing PCI in the non-acute setting,” the authors wrote. “Better understanding of the clinical settings in which inappropriate PCIs occur and reduction in their variation across hospitals should be targets for quality improvement.”