The objective of the study is to determine that a coronary angiography (CAG) or percutaneous coronary intervention (PCI) via a distal puncture of the radial artery (distal transradial access, dTRA) leads to a lower rate of radial artery occlusion (RAO) while also showing that it has a similar success rate when compared to the traditional proximal (proximal transradial access, pTRA) puncture site.

Cardiac catheterization is one of the most common invasive procedures worldwide. After demonstrating the superiority of the radial access over the femoral arterial approach, the radial artery puncture has become the first choice for elective and emergency coronary interventions. In addition to the often chosen access on the inside of the forearm, the course of the radial artery also allows a puncture further distal on the back of the hand. In the anatomical snuffbox, the diameter is still sufficient for the introduction of the usual sheath, however, the thrombogenic puncture at the proximal radial segment is avoided and a hemostasis by compression over the scaphoid is simplified.

This study is a prospective, open-label, randomized, multicenter study to systematically compare primary success rates and potential complications after distal transradial coronary angiography or coronary intervention versus proximal radial artery puncture over the wrist. Both puncture routes are well established in clinical routine and are used in both elective and emergency cardiac catheterization in the centers involved and worldwide. Systematic comparisons exist so far only in small series, but randomized and prospective data would be urgently needed in the frequent application. Both puncture sites are only 4-8 cm apart, so that many risks of a transradial examination (vascular injury and / or closure, perforation, spasm) are in principle common to both access sites.

The purpose of this study is to demonstrate the potential benefits of radial artery puncture in the back of the hand due to a reduced rate of chronic vascular occlusion compared to over the wrist, as well as complications (bleeding or nerve damage) and subjective tolerability ( Pain) systematically.

Inclusion Criteria:

• Written consent to participate in the study
• Age ≥ 18 years
• Indication for coronary angiography or coronary intervention
• Palpable pulse of the proximal and distal radial artery on one or both arms

Exclusion Criteria:

• Hemodynamic instability (according to the criteria of cardiogenic shock: Hf> 120 / min and RR syst <90 mmHg)
• Intubated patients
• Sonographic evidence of occlusion of both radial arteries
• Pregnant or lactating women
• Patients that are currently or have within the last 30 days participated in a clinical trial
• Primarily planned bilateral radial access; e.g. in the context of a CTO recanalization
• Patients who are in a dependency / employment/ relationship with the study doctor or center
• Patients with bilateral hand or arm misalignment / paresis that makes a radial Access impossible
• Patients who do not speak German or who are unable to understand the nature, significance or scope of the study