A growing body of evidence suggests that a transradial intervention rather than a transfemoral approach to PCI is associated with greater reductions in bleeding complications than those achieved with pharmacological strategies alone.

Whilst the transfemoral approach to cardiac catheterization has dominated the huge growth of invasive cardiology to date, transradial access appeared early in the development of cardiac catheterization techniques as early as 1948.

Despite early enthusiasm for the approach, equipment limitations resulted in a shift to larger vessels for most catheter-based procedures, and the radial artery was consigned as a site for monitoring arterial pressure.

In the late 1970s, percutaneous coronary angioplasty was introduced using predominantly 9-F guiding catheters. Building on reports of successful transradial angiography from Canada in 1989, four years later, Kiemeneij and Laarman first reported on the transradial approach for coronary stenting.

Given observed reductions in periprocedural bleeding and reported improvements in patient comfort, a few enthusiastic early adopters surfaced, although transradial intervention generally remained a niche technique. The greater technical complexity of the procedure compared to the transfemoral procedure and the associated significant learning curve hindered its uptake.

As experience with transradial intervention grew, the lack of severe access-site complications when compared with the transfemoral approach to coronary angiography and coronary intervention was repeatedly demonstrated in small observational studies.

Cost-effectiveness was also demonstrated and small single-centre or limited multicenter randomised comparisons to femoral and brachial approaches showed the superiority of transradial intervention with respect to vascular access site complications, patient preference and speed of post-procedural recovery.

There are important veins or nerves near to the radial artery in the wrist, which decreases the likelihood of arteriovenous fistulas or nerve lesions; the superficial trajectory of the artery and its proximity to the bone allow simple hemostasis by means of simple compression, bypassing the need for closure devices and decreasing the chance of hematoma and pseudoaneurysm.

Several studies have reported that the patients can ambulate almost immediately following the procedure, which increases the patient´s comfort and level of satisfaction, and at the same time decreases the length of hospital stay and the cost.

Nevertheless, the procedure could only be performed with safety in patients with a normal Allen test, and technically, the procedure is more complex than the transfemoral procedure due to the greater difficulty in cannulating the artery, variations in the arteries of the upper limb, possibility of spasm, and the manipulation of the catheters that is necessary to cannulate the coronary arteries.

These difficulties result in a slight increase in the length of time needed for the procedure and time needed for fluoroscopy. There is also a significant learning curve involved, even for specialists with a a lot of experience in transfemoral procedures.

However, ESC Guidelines published last year give the highly recommend the radial approach over the femoral one for coronary angiography and percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS). The ACS without persistent ST-segment elevation (NSTE-ACS) guidelines are published online on the ESC Website and in European Heart Journal.