Link Between PCI Volume and Outcomes Remains Intact

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Outcomes from percutaneous coronary intervention (PCI) have been excellent overall in recent years, but operators with the highest procedure volumes stand above the rest in terms of adverse events, lengths of stay, and costs, according to a study published online September 4, 2014, ahead of print in Circulation.

The rate of all-cause in-hospital mortality (primary outcome) was 1.08% and the rate of periprocedural complications was 7.10%, with the most common being vascular problems (2.01%), cardiac complications (1.76%), postoperative respiratory failure (1.50%), and postoperative stroke (0.99%).

In-hospital mortality and the composite of in-hospital mortality and periprocedural complications (secondary outcome) both became increasingly frequent across quartiles of declining PCI volume at the operator level, trends that remained significant (P < .001) after adjustment for potential confounders (table 1).

Table 1. Outcomes by Operator Volume (Annual Number of Procedures)

In addition, the average length of stay fell from 4.12 days among operators with the lowest volumes to 2.01 days for those with the highest, and average hospitalization costs dropped from $21,111 to $15,783 (P < .001 for both). 

Similar relationships were seen between institutional procedure volume and outcomes, although the associations were rendered nonsignificant after operator volume was added to the models. 

How Much Volume Is Needed to Remain Proficient?

The latest clinical competence statement from the American College of Cardiology Foundation, American Heart Association, and Society for Cardiovascular Angiography and Interventions (ACCF/AHA/SCAI)—issued in 2013—recommends a minimum of 50 coronary interventional procedures per year (averaged over 2 years) at the operator level and 200 procedures per year at the hospital level to maintain competency to perform PCI. That is a change from a threshold of 75 procedures at the operator level in earlier documents, a decision made in response to the decline in overall PCI volumes in recent years. 

Dr. Badheka and colleagues explored outcomes associated with cutoffs of < 50, 50 to 75, and >75 and found that rates of both in-hospital mortality and the composite of in-hospital mortality and periprocedural complications declined as the bar was raised. 

“Although PCI outcomes have improved and volume has declined over the years, the relationship between PCI volume and outcome still seems intact,” they write. “One reason for this finding could be that higher volume physicians [are] well versed with clinical practice guidelines, implementing them more often. … Another reason could be familiarity with treating PCI complications and emergencies amongst higher-volume physicians.” 

In an accompanying editorial, David J. Cohen, MD, of Saint Luke’s Mid America Heart Institute (Kansas City, MO), and colleagues point out some limitations of the analysis, including the use of administrative claims instead of clinical data, the inclusion of information on inpatient procedures only, and the exclusion of nearly half of the procedures performed during the study period because of missing unique operator identifying numbers. They add, however, that it is the “largest and most contemporary” study of the issue and that it is consistent with earlier research.

“One of the more sobering, albeit subtle, findings from this study was that the median operator PCI volume was 75 cases/year, with a substantial fraction of operators falling below 50 PCIs per year—a level that barely meets current ACCF/AHA/SCAI recommendations,” Dr. Cohen and colleagues write.

“While these numbers may have underestimated true operator volume by excluding outpatient procedures… they nonetheless fall far below the ‘optimal’ threshold of ~300/year identified in their study,” they continue. “As such, the trend of declining PCI volumes coupled with a clearly defined volume-outcome relationship could spell trouble for PCI patients in the years to come.”

Sources:
1. Badheka AO, Patel NJ, Grover P, et al. Impact of annual operator and institutional volume on percutaneous coronary intervention outcomes: a 5-year United States experience (2005-2009). Circulation. 2014;Epub ahead of print.
2. Baron SJ, Yeh RW, Cohen DJ. The challenges of success: maintaining access to high-quality PCI in the face of declining procedural volumes [editorial]. Circulation. 2014;Epub ahead of print.

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