Introduction

The cardiac catheterization history is one filled with innovation and taking a step further over unexplored terrain. Ever since the first recorded self-catheterization performed by Werner Forßmann - aided by the operating-room nurse Gerda Ditzen - until the most recent advances in percutaneous structural heart interventions (such as transcatheter aortic valve replacement - TAVR), the main focus of the catheterization laboratory (cath lab, for short) practice was to improve the number and range of ^{performed interventions}. One of those is the coronary angiography, consisting on the injection of a contrast medium through a coronary artery, under the use of x-ray, to assess its anatomy. An arterial (or venous) access is needed to perform a cardiac catheterization, as it is known from Werner Forßmann's personal experience. This technique has been used and perfected over the past decades and is essential for a great number of percutaneous cardiac interventions. The first access that was used, and the one that is still preferred for complex interventions such as TAVR, mechanical circulatory support and chronic total occlusion angioplasty, is the ^{femoral artery approach}. However, there is a shift towards the radial artery (RA) approach due to the reduced risk for vascular and bleeding complications and the verified survival benefit in ST-segment-elevation myocardial infarction patients who undergo primary percutaneous coronary intervention (PCI). In 1947, Radner first reported an aortography via RA and since then, until ^Campeau (1989) and Kiemeneij (1993) started diffusing this approach, a case favoring the radial access has been made. The past decade has given a solid body of evidence in favor of the RA approach, mostly because of the results of trials like RIVAL (2011), RIFLE-STEACS (2012), STEMI-RADIAL (2014) and MATRIX (2015), which certified the benefits of the ^{radial vs femoral artery access}.

The RA has some distinctive characteristics that made it eligible for use in the field of interventional cardiology (IC). On the one hand, it is a superficial artery, easily palpable and compressible, with sufficient diameter (2.69 ± 0.40 mm in men and 2.43 ± 0.38 mm in women (range 1.15 mm to 3.95 mm) to perform diagnostic and interventional procedures, and isolated from major nerves and veins. On the other hand, its limited diameter, ^tortuosity and higher reactivity for spasm render a steeper learning curve. In addition to the latter, there is the possibility of radial artery occlusion (RAO), which will compromise future interventions on this access site. This is a serious concern, given that the ageing of the population comes with a larger propensity for chronic diseases, multimorbidity, and the possibility for multiple interventions, given state of the art in IC. According to the PROPHET and PROPHET-II studies, patent hemostasis and prophylactic ulnar compression reduce RAO. Furthermore, a shorter duration of the RA compression and the use of anticoagulants - local or systemic - and locally administered vasodilators proved effective at reducing RAO. Resolving these problems may allow an early patient discharge allowing a more significant number of procedures, improving its cost-effectiveness, and assuring better patient satisfaction by limiting the length of stay.

In this evolving landscape, the industry never failed to provide solutions to new ideas or perfect old ways with better materials. Apart from the tools needed to perform the vascular access, its closure is also an issue. When it comes to hemostatic devices, the RA takes the win, with solutions that range from hemostatic patches to compression devices, in ^{multiple shapes and manners}. On the one hand, there is the manual compression, consisting of applying constant pressure over the puncture site until bleeding is stopped, followed by applying a compression bandage - two or more strips of elastic material - over said site. On the other hand, the mechanical or device focused one, e.g., TR-BAND® (Terumo®, Japan), consists of applying pressure over the puncture site. The use of devices allows reallocating valuable and differentiated human resources. The hemostasis protocol has varied since it first appeared, and from one cath lab to another. Several methods have been tried, to balance adequate hemostasis while avoiding RAO, using different inflation times, time to first deflation and total weaning, and non-fractioned heparin doses in-procedure. Here we must take into account that ^TR-BAND is the most widely used and studied pneumatic compression device. Despite Terumo itself now recommending the permeable hemostasis protocol requiring that the blood flow through the RA is maintained while the hemostasis occurs - patent hemostasis, there is no standard protocol for total time of compression nor weaning times. The last review of the protocol by Terumo, as well has the lack of a standardized protocol, have sparked our interest in what else has changed concerning state of the art on ^{RA hemostasis}.

Thus, the authors aim to map the available evidence on the previous subject by conducting a preliminary search of MEDLINE (PubMed), the Cochrane Database of Systematic Reviews, the JBI Evidence Synthesis, PROSPERO and Open Science Framework (OSF).

No current or underway ^{scoping reviews} or systematic reviews were identified. Therefore, this scoping review attempts to:

Review question(s):

Inclusion criteria:

1) Participants:

The feasibility and safety of the RA approach in children and adolescents, as well as the use of hemostasis methods and associated protocols, makes a case for including them as participants, thus this scoping review will include research studies that include all patients, of all ages and of both sexes, who ^{underwent coronary angiography}.

2) Concept:

This review will consider research studies that explore hemostasis methods used after a coronary angiography via radial artery puncture.

3) Context:

This review will consider original research studies and review articles including systematic reviews, meta-analysis, meta-synthesis, narrative reviews, mixed-methods reviews and qualitative reviews that refer to coronary angiographies performed via radial artery.

4)Types of sources

This scoping review will consider quantitative, qualitative and mixed methods study designs for inclusion, as well as grey literature sources. In addition, systematic reviews will be considered for inclusion in the proposed scoping review.

1. Methods

Given all the various approaches available for reviewing the literature: a) scoping review versus b) systematic review - a ^{scoping review} is the most suitable one, because of the object of this work. The first goal is to produce an overall map of what evidence has been produced, which contrasts with the latter’s that is to find a solid defined answer to a question related to practice.

Thus, the proposed scoping review protocol will be conducted in accordance with the ^{Joanna Briggs Institute (JBI)} methodology latest guidance.

Acknowledgements

We wish to acknowledge Cecilia Rodrigues, PhD, for assistance with the study.