**3.3. Advances in angioplasty**

Angioplasty has significantly evolved over the last several decades with respect to four principle areas. First, operator training has advanced from informal training courses to 1-2 year formal clinical fellowships [12, 13]. Second, the equipment to perform PCI has signifi‐ cantly improved from plain old balloon angioplasty (POBA) to second-generation drugeluting stents (DES) and supporting devices to improve PCI outcomes (filter wires, thrombectomy in ST elevation acute coronary syndrome (STEACS), and rotational arthrecto‐ my) [14, 15]. Third, vascular access has evolved from brachial cut-downs with large caliber sheaths (7-8 FR) to increasingly common radial access with smaller caliber sheaths (5 and 6 FR) [5, 15-18]. Finally, concomitant medications have become more sophisticated, from Aspirin (ASA) alone to combination antiplatelets resulting in reduced stent thrombosis [19]. Restenosis has remained in the forefront of limitation to PCI[20]. However, the challenges with restenosis have been significantly reduced with advancement in DES technology [21-23]. Concerns with the thrombosis rates in the setting of discontinuation of dual antiplatelet therapy (DAPT) after DES have been addressed by second-generation DES, which have dramatically reduced this clinical problem [24]. These advances have been paralleled by an increasing use in complex coronary artery disease including left main (LM) disease[25].
