PCI volume-outcome link holds but threshold is unclear

Volume appears to be key in quality outcomes for PCI, however, the threshold number a provider must perform per year to stay in top form remains elusive, a study published June 17 in Circulation: Cardiovascular Quality and Outcomes stated.

While overall numbers of eligible patients are falling due to improved prevention care and alternate intervention methods, the number of facilities offering PCI and the number of trained interventionalists have grown. Thresholds established by professional groups to maintain standards have been reduced in recent years, recommending that certified interventionalists perform 50 or more PCIs in a year, down from 75.

A research team led by Jordan B. Strom, MD, of Massachusetts General Hospital in Boston, collected data from 23 studies on PCI outcomes and volume with an eye on determining a threshold. They found high variability in detail between studies, even if none of the studies they included could be considered of low quality. All studies lacked enough detail to give exact thresholds for best PCI outcomes. Still, they were able to determine that the more PCIs performed by a facility or provider, rates for both major adverse cardiovascular events (MACE) and mortality were subsequently lower.

Particularly, 63 percent of studies included reported significant relationships between increased risk of MACE and lower operator volume. A mean reduction in MACE between the higher-volume cohorts and lower-volume cohorts was 39 percent.

Mortality results were not as clear, several suggesting volumes as low as 11 or greater, others still suggesting as many as 75. All agree that for best care, operators should perform more than a handful a year.

However, Strom et al noted that among the studies they reviewed, there was a notable trend toward increased MACE among operators with volumes as high as 50 PCIs per year and increased mortality around 11 PCIs per year.

They recommended consolidation of PCIs to fewer centers to provide more volume to operators, thereby increasing positive outcomes.