Valle JA, et al. - This cross-sectional multicenter study draws on data from 1,662 institutions participating in the National Cardiovascular Data Registry (NCDR) CathPCI Registry between April 2009 and July 2016 to define the current practice of unprotected left main (ULM) percutaneous coronary intervention (PCI) and its outcomes. Researchers compared these with findings reported in clinical trials. Data were collected from 33,128 ULM PCI patients and 3,309,034 PCI patients. Patients in the CathPCI Registry were older with more comorbid conditions vs clinical trial populations, and adverse events were more common. Over time, the use of ULM PCI has increased from 0.7% to 1.3%, but overall use is low. These findings suggest that ULM PCI does not occur frequently in the United States and in an older and more comorbid population than in clinical trials.