Comparison between left and right radial access for coronary angiography

Since the 1940s, various methods for creating vascular access have been described. In 1929 Werner Forssman who at the time was a surgical resident performs the fi rst catheterization using a urinary catheter [1]. In 1941 Fariñas described the passage of an urinary catheter through a trocar placed in the femoral artery to perform an aortography [2]. In1947 Radner through a dissecting artery exposed the radial artery and performed a vertebral angiography. In 1949 Jönsson performed an aortography performing a puncture at the common carotid artery using a blunt cannula with a needle the cannula was inserted through a silver wire. In 1953 Dr. Sven Ivar Seldinger described a technique which consisted of performing a puncture using a stylet, subsequently a 3 cm fl exible guidewire was inserted, the needle was withdrawn and the vessel was compressed, at the meantime a catheter was passed through the fl exible guidewire through the puncture site and fi nally the Abstract


Introduction
Since the 1940s, various methods for creating vascular access have been described. In 1929 Werner Forssman who at the time was a surgical resident performs the fi rst catheterization using a urinary catheter [1]. In 1941 Fariñas described the passage of an urinary catheter through a trocar placed in the femoral artery to perform an aortography [2]. In1947 Radner through a dissecting artery exposed the radial artery and guidewire was withdrawn guide [3]. Dotter and Judkins (who described femoral access for coronary angiography) in 1964 performed the fi rst transluminal angioplasty in an 83-yearold patient, showing a decrease in temperature and pain of a pelvic limb and who refused to be amputated, they used a tefl on-coated catheter to dilate the stenotic area [4,5]. In 1977 Dr. Andreas Gruetzing performed the fi rst successful coronary angioplasty in a human being, a ballon was mounted at his catheter.
Since Judkins' description of femoral access, this has become the standard for performing coronary angiography and angioplasty. The common femoral artery is considered the safest arterial puncture site since the path of this vessel passes over a bone structure that facilitates compression for hemostasis. However, this type of access is related to complications such as the formation of pseudoaneurysms, arteriovenous fi stulas or distal thrombosis [6,7]. These complications have been shown to have a prognostic impact on the patient, however, in various studies it has a low incidence of 2.4%, in the setting of primary coronary angioplasty [8].
In 1989 Campeau at the Montreal Heart Institute described radial access in 100 patients programmed for elective coronarography using a 5 Fr sheath, in 10 patients radial artery puncture could not be performed and in 2 patients coronary artery cannulation was not possible, in the original technique description the left arm was abducted at a 70º angle with the wrist in hyperextension.
For left radial access, an 18 G needle was used, using a posterior puncture technique for large arteries and anterior wall for small arteries, a 23 cms 5 Fr sheath was used of 23 cms [9,10].
In 1995 Ferdinand Kiemeneij described the technique for radial coronary angioplasty placing the thoracic limb in 70º of abduction with the wrist in hyperextension using a 22 G needle and puncturing the anterior arterial wall, thereafter the application of this technique has gone from being one more option to the fi rst access route used in primary angioplasty.
Recently in 2017 Kiemeneij described the left radial access technique through the anatomic snuff box in 70 patients as a possible and safe technique with the advantage of using femoral angiographic catheters that follow the "natural" route through the left aortic arch, In addition, puncturing at the distal level reduces the risk of occlusion of the palmar arch [11]. There have been recent publications of single center´s experience that describes the use of left distal radial artery with good results with no equipment or investment necessary to support left arm, Nairoukh reported that distal radial diameter is 80% smaller, he described variations among different countries, the largest diameter was found in Korean patients and the smaller in patients from Singapore [12]. Kim, et al. found that left distal radial access was feasible and the success rate of radial artery cannulation was 88% with minor vascular complications such as forearm swelling and bruises [13]. Mizuguchi, et al. in Japan made a multicentric study aimed to investigate radial patency and hemorrhagic events by performing vascular ultrasound before and after interventional procedure, they found no bleeding complications and a low incidence of radial artery occlusion [14].

Primary outcomes
Compare left and right radial approach based on: • Patient comfort • Amount of contrast used between left and right radial access.
• Distance between the fl uoroscope and the operator. Study population: Patients requiring coronary angiography, who are hemodynamically stable and having favorable characteristics for radial access.
Stratifi ed randomization by center in blocks of 10 [4]. B1 I

Inclusion criteria
• Patients over 18 years.
• Indication of preoperative coronary angiography.
• Coronary angiography with probable percutaneous transluminal coronary angioplasty in Acute Coronary Syndrome.

Exclusion criteria
• Patients with Renal Insuffi ciency.
• Barbeu C or D patients.

Elimination criteria
• Patients who refuse to participate in the protocol.
• Patients in whom it is decided to use the femoral approach from the beginning.
Before each procedure an envelope was opened which contained the assigned access, an informed consent and data collection sheet. Each patient received information about data collection, technical aspects, risks, and the advantages of participating in the study, and the informed consent was signed. Data collection started with the patient's perception of comfort in relation to the position of the access site using a Likert scale (5 totally agree, 4 agree, 3 indifferent, 2 disagree, 1 totally disagree). Subsequently, distance between the fl uoroscope and the operator´s left shoulder was measured in centimeters using a tape. Once having knowledge of the assigned approach to carry out, the fi rst operator freely chose the puncture site either at the wrist level or in the anatomic snuff box. Once the access site was obtained, the fl uoroscopy time was recorded by the cath lab technician, data related to coronary angiography was collected such as type of angiographic catheter, if the patient had some anatomical variation such as loops, variations in the morphology of the aortic arch, variations in the position of the coronary ostiums or abnormal origins this was reported on the collection sheet as abnormal anatomy, otherwise as normal anatomy; if the patient presented radial artery spasm, it was recorded on the data collection sheet as well. At the end of the procedure, the participant was asked on comfort perception again.
Presence of bleeding after the procedure or until hospital discharge, was classifi ed according to the Bleeding scale Academic Research Consortium from 0 to 5 ( 0 = No bleeding, 1 = Bleeding that does not merit medical care, 2 = Bleeding that merits studies and hospitalization, 3 = Requires surgical intervention to be controlled, 4 = Surgery related bleeding of bridges, 5 = Fatal leading to death) For the purpose of comparing comfort in patients with a right vs. left radial approach, a comparison of means (the group "Radial right" vs. "Radial left" was compared), the dependent variable was the degree of comfort according to the Likert scale, where the highest convenience or comfort was coded with a higher numerical value; (see annexes for more details).

Statistic analysis
• Firstly, an exploratory analysis of the database was done to determine whether missing values existed.
• Subsequently descriptive statistics was performed: the information was summarized with mean and standard deviation and interquartile range for the quantitative variables, according to the distribution. The qualitative variables were described as absolute and relative frequencies.
• For inferential statistics, the groups were compared (left vs. right radial route) • With Student's T or Mann-Whitney U for quantitative variables (according to distribution); • Chi square was used for qualitative variables.
• A value of p <0.05 was considered statistically signifi cant. C. This study has an informed consent form, which was applied after the personalized explanation of the protocol's objective and prior to carrying out questionnaires.

Ethical aspects
D. The contributions of this study to participants and society lie in the progress knowledge of comfort in performing these procedures, both for the patient as for the operator.
F. The information obtained as part of this study is strictly confi dential. 55 patients who were randomized (age 62 ± 12 years, men 78%), 27 were randomized to the coronary angiography by left radial access and 28 by right radial access coronary angiography ( Figure 1). 23 of the left approaches were made at the snuffbox (83%, p = 0.001) and 4 at the wrist level; on the other hand 11 of the right radial approaches were performed at the distal level and 17 at the wrist level. The indications to carry out coronary angiography were: ischemic heart disease (the most frequent) (60% left, vs 43% right), acute coronary syndromes without ST-segment elevation were the second more frequent indication (22% left radial vs. 32% right radial), followed by acute coronaries with ST segment elevation (7% left radial vs. 11% right radial) and in fourth place was coronary angiography prior to cardiac surgery (11% left vs 7% right), without statistically signifi cant difference (      it at the wrist; in another patient the operator could not obtain distal access either and right radial access was performed with a conventional technique; and in the last 2, a femoral approach was used after spasm. The p value for the difference of change of right vs. left access was = 0.051 ( Figure 11).

Discussion
This is the fi rst study to randomly assess left radial approach versus right radial approach, in patients who undergo coronary angiography introducing a novel comparison of patient comfort, an aspect that seems to be of little importance at the time of taking a coronary angiography but that can take signifi cance when procedures become prolonged. In the technical aspect of the procedure, the decision of performing conventional or distal access was not a randomization parameter since not all researchers are trained in both techniques; on both approaches, coronary projections and ventriculography could be performed          The comfort aspect is a very subjective parameter for which there is no specifi c scale of measurement. A Likert scale was used to rate the parameter from 1 to 5, from being strongly disagree (1), disagree (2), be indifferent (3), agree (4) and (5) strongly agree, during the study the majority of patients rated agreeing that the two types of access are comfortable before, during and after the procedure without fi nding a statistically signifi cant difference which contradicts our hypothesis that assumed the left access as more comfortable. For the purposes of this study, the perception of comfort between wrist level or in the anatomic snuffbox was not investigated, and it could be reason for future research. Both access routes were safe, only 4 patients presented small bruises at the puncture site that did not warrant medical attention; we had more cases with artery spasm in the left access group compared to the right, this is probably related to the learning curve for the different techniques, despite this there was no difference that had statistical signifi cance. Within the rest of the objectives there was a strong tendency to change the access site in left procedures almost reaching statistical signifi cance, in two cases after attempting distal puncture and not being able to obtain the access conventional puncture was done, there were also two cases were spasm was presented and operators changed to the femoral route. In the right access only one change to the femoral route was made because an anomalous origin of right coronary artery emerging from the left valsalva sinus made diffi cult to cannulate by radial approach, this phenomenon possibly is also related to the learning curve of the left techniques, also the researchers. Initially, the acquisition of a radiation dosimeter was considered, however, when having patients of different centers could not homogenize the radiation measurements since each center has assigned different dates to obtain said reading, it was decided to have a simple and indirect method to assess the exposure so the distance between the intensifi er and the operator left shoulder was the defi ned method for assessing radiation, however our measurement is not a parameter reliable nor is it known what the specifi c correlation is with the amount of radiation.

Conclusions
The present study shows that the left radial access made distally or in the carpal region is safe in terms of bleeding or spasm when compared to right access approach. Judkins diagnostic catheters and TIG catheters can be used despite differences in support mechanics and cannulation maneuvers, and ventriculography is feasible. In the other hand is not an access that has been shown to be superior in comfort despite that in right technique the arm is slightly abducted at the time of the procedure. Left approach can be used in different clinical settings for either elective or emergency procedures, and is a valuable alternative either to be used as a fi rst choice or as an option secondary when no good pulses are found on the right side or when you want to protect the integrity of the right radial artery to be used as a vascular graft in surgery of revascularization.