This document discusses complications that can occur during percutaneous coronary intervention (PCI) procedures. It notes that while PCI has over a 90% success rate, complications still occur in 1-5% of cases. It identifies several factors that can increase the risk of complications, such as advanced age, urgent procedures, and comorbidities like heart failure or diabetes. The document categorizes types of potential complications and discusses some in more depth, such as vascular access complications, dissections, and perforations. It also examines angiographic and technical factors that can influence complications, as well as indications for emergency cardiac surgery following PCI.