Transradial approach to cardiovascular interventions: an update.

The history of cardiac catheterization began in 1711 with an equine biventricular catheterization and progressed through the centuries.1 In 1929, German physician Forssmann boldly performed a right heart catheterization on himself, and subsequently shared the 1956 Nobel Prize in Medicine with Columbia University physicians Cournand and Richards for the development of cardiac catheterization.1 The actions of these medical pioneers paved the way for modern interventions of the heart and coronary arteries, prompting the advent of interventional cardiology.1 In 1989 Campeau was able to perform the first diagnostic cardiac catheterization via the radial artery, and in 1993 Kemeneij and Laarman were able to complete a radial access percutaneous coronary artery intervention, a procedure involving angioplasty and stenting.2 With regards to arterial access site, the femoral artery and radial artery are routinely selected. For patients in whom radial and femoral access is impossible, the brachial method is sometimes employed, though less desirable due to the risk of complications, including neuropathy.3 4 Rarely, experienced operators opt for axillary entrance.3 Unfortunately, major weaknesses of catheter-based procedures are the risks of acute vessel closure, restenosis, bleeding, and pseudoaneurysm.1 3 Overall analysis of complications in 200,000 patients undergoing diagnostic cardiac catheterization indicates that less than 1% of patients experience vascular complications such as thrombosis, pseudoaneurysms, or bleeding requiring transfusion.3 Much research in the last 30 years has been devoted to determining which access site is best suited for particular patients and circumstances; as technological advances expand the boundaries of possibilities, this work continues. In spite of the efficacy of femoral catheterizations for cardiac procedures, vascular bleeding complications give rise to increased morbidity and duration of hospitalization, especially when aggravated by aggressive anticoagulation and antiplatelet treatment.5 6 The femoral approach has been compared with the radial approach for both diagnostic and interventional procedures in multiple randomized trials and observational studies. An important advantage of the radial artery is that unlike the brachial and femoral arteries, it is not an end artery, so even in the event of occlusion, blood from collateral arteries will prevent ischemia of the territory that it supplies. Current literature suggests lower rates of vascular and neurological complications in radial access procedures since the artery is more compressible, facilitating sheath removal, and not immediately associated with a nerve. Numerous studies also report earlier patient discharge, earlier time to ambulation, patient preference for the procedure, and a shorter recovery period associated with radial access.7 A potential complication with the procedure is radial artery occlusion, which hinders future radial access and use of the artery for dialysis fistulas and bypass grafts.8 The reported rates of radial artery occlusion vary widely, spanning 5 to 40% depending on institution and study specific protocol.9 10 However, hand ischemia is largely preventable if the patient's ulnar supply to the palmar arch is assessed before the procedure by Allen test.8 We aim to review praxes and trends of transradial catheterization procedures across the globe, paying particular attention to metrics of cost-effectiveness, procedural safety, complications, and effectiveness across a variety of clinical scenarios.