BackgroundThe American College of Cardiology / American Heart Association (ACC/AHA) introduced a coronary lesion classification in 1988 to stratify coronary lesions for probability of procedural success and complications after coronary angioplasty. Our aim is to assess the validity of the ACC/AHA lesion classification in predicting outcomes of percutaneous coronary intervention (PCI) in a contemporary cohort of patients. MethodsConsecutive PCI procedures performed between 2005 and 2018, were divided into three periods. At each period, the ACC/AHA lesion classification (A, B1, B2, C) was analysed with respect to procedural characteristics, in-hospital and 30-day outcomes, as well as long-term mortality by linkage to the National Death Index (NDI). ResultsIn total, 21,437 lesions were included with 7399 lesions (2005–2009), 6917 lesions (2010–2014) and 7121 lesions (2015–2018). There was a progressive increase in the number of complex lesions treated over time with ACC/AHA type C (15 %, 21 % and 26 %, p < 0.01). The rate of PCI procedural success decreased with increase in the complexity of lesions treated across all three periods (p < 0.01). Further, in-hospital and 30-day major adverse cardiovascular events (MACE), major adverse cardiac and cerebrovascular events (MACCE) increased across all three time periods (all p < 0.05). ConclusionsOur study validates the ACC/AHA lesion classification as a meaningful tool for prediction of PCI outcomes. Despite advances in PCI techniques and technology, complex lesion PCI defined by this classification continues to be associated with adverse outcomes.