Learning curve in the use of the radial artery as vascular access in the performance of percutaneous transluminal coronary angioplasty

Does the Use of Ethyl Chloride Spray Facilitate Radial Angiography?

Ethyl chloride (EC) spray is a vapocoolant which is used in interventional procedures as a topical local anesthetic. The aim of the present study was to investigate whether or not EC spray can facilitate radial coronary angiography. The study was conducted on a study group EC of 106 (age: 58.1 ± 12.4) patients and a control group (placebo) of 104 (age: 59.1 ± 10.8) patients. Visual analogue scale scores (VAS), radial cannulation failure (RCF), the rates of clinical and anatomical radial artery spasm (RAS), pain lasting >2 day and >1 week, and radial artery occlusion (RAO) at first week and first month were evaluated in both groups. VAS scores, the rates of RCF, clinical and anatomical RAS and pain lasting >1 week were found significantly lower in the study group than the control group (p < .001, p = .024, p=.009, p = .028 and p = .042, respectively). But the rates of RAO were similar in both groups. Topical spray including EC, which has low-cost and rapid efficacy, may be preferred in transradial coronary angiography as it reduces the risk of RCF and RAS, and increases patient comfort with its analgesic effect, without significant side-effects.

Simulating complex patient populations with hierarchical learning effects to support methods development for post-market surveillance

BACKGROUND

Validating new algorithms, such as methods to disentangle intrinsic treatment risk from risk associated with experiential learning of novel treatments, often requires knowing the ground truth for data characteristics under investigation. Since the ground truth is inaccessible in real world data, simulation studies using synthetic datasets that mimic complex clinical environments are essential. We describe and evaluate a generalizable framework for injecting hierarchical learning effects within a robust data generation process that incorporates the magnitude of intrinsic risk and accounts for known critical elements in clinical data relationships.

METHODS

We present a multi-step data generating process with customizable options and flexible modules to support a variety of simulation requirements. Synthetic patients with nonlinear and correlated features are assigned to provider and institution case series. The probability of treatment and outcome assignment are associated with patient features based on user definitions. Risk due to experiential learning by providers and/or institutions when novel treatments are introduced is injected at various speeds and magnitudes. To further reflect real-world complexity, users can request missing values and omitted variables. We illustrate an implementation of our method in a case study using MIMIC-III data for reference patient feature distributions.

RESULTS

Realized data characteristics in the simulated data reflected specified values. Apparent deviations in treatment effects and feature distributions, though not statistically significant, were most common in small datasets (n < 3000) and attributable to random noise and variability in estimating realized values in small samples. When learning effects were specified, synthetic datasets exhibited changes in the probability of an adverse outcomes as cases accrued for the treatment group impacted by learning and stable probabilities as cases accrued for the treatment group not affected by learning.

CONCLUSIONS

Our framework extends clinical data simulation techniques beyond generation of patient features to incorporate hierarchical learning effects. This enables the complex simulation studies required to develop and rigorously test algorithms developed to disentangle treatment safety signals from the effects of experiential learning. By supporting such efforts, this work can help identify training opportunities, avoid unwarranted restriction of access to medical advances, and hasten treatment improvements.

The efficacy of nitroglycerin to prevent radial artery spasm and occlusion during and after transradial catheterization: A systematic review and meta-analysis of randomized controlled trials

Radial artery spasm (RAS) is the most common cause of transradial access site crossover and is a common intra-procedural complication. RAS incidence can lead to radial artery occlusion (RAO) postprocedure, preventing the radial artery as a future access site. We evaluated the efficacy of nitroglycerin preventing RAS and RAO during transradial catheterization discussing the different routes of administration, including topical, subcutaneous, and intra-arterial. A systematic review and meta-analysis included all relevant articles until April 23, 2022. We searched six databases Google Scholar, Web of Science, SCOPUS, EMBASE, PubMed (MEDLINE), and CENTRAL. We registered our review protocol in PROSPERO with ID: CRD42022330356. We included 11 trials with 5814 patients. Compared to placebo, the pooled analysis favored subcutaneous nitroglycerin in preventing RAS (risk ratio [RR]: 0.57 with 95% confidence interval [CI] [0.43-0.77], p = .0003) and RAO (RR: 0.39 with 95% CI [0.16-0.98], p = .05). In contrast to the intra-arterial nitroglycerin that showed nonstatistically significant results in preventing RAS and RAO (RR: 0.8 with 95% CI [0.63-1.02], p = .07)- (RR: 0.78 with 95% CI [0.6-1.01], p = .06)), respectively. Also, topical nitroglycerin did not prevent RAS (RR: 0.73 with 95% CI [0.42-1.24], p = .24). Compared with placebo, subcutaneous nitroglycerin during transradial catheterization reduced the incidence of RAS and RAO. Meanwhile, Intra-arterial and topical nitroglycerin did not show statistically significant outcomes. Subcutaneous nitroglycerin may be a practical and cost-effective technique to facilitate transradial catheterization; however, more RCTs are needed to evaluate the subcutaneous versus intra-arterial nitroglycerin administration.

Correlation of a guidewire maximum insertion length with tortuous radial artery and the success rate during transradial coronary angiography

Background

Percutaneous coronary intervention (PCI) is a safe and effective therapy for patients with obstructive coronary artery disease (CAD). We aimed to assess the correlation between the success rate of angiography and the maximum insertion length and resistance of a soft-tipped guidewire.

Methods

Five hundred twenty-one patients were treated by successful radial artery puncture. According to whether the guidewire resistance, the patients were divided to three groups. 17 patients were maximum insertion length of guidewire ≤ 30 cm when resistance was encountered (group 1). 17 patients were maximum insertion length of guidewire between 30 and 45 cm when resistance was encountered (group 2). 487 patients were no resistance encountered (group 3).

Results

The coronary angiography success rates of group 1, 2, and 3 were 52.94%, 47.05%, 98.97%, respectively. Typically, angiography can be completed in patients with Ω-shaped, S-shape or Z-shaped tortuosity.

Conclusions

The maximum insertion length of straight guidewire and resistance can be used to determine radial artery status. The radial artery tortuosity or spasm significantly affects the success rate of coronary angiography.

Transradial Neuroendovascular Procedures in Adolescents: Initial Single-Center Experience

BACKGROUND AND PURPOSE

The feasibility and safety of transradial angiography is not established outside the adult literature. The objective of this study was to assess the feasibility and safety of transradial access for neuroangiography in adolescents.

MATERIALS AND METHODS

A retrospective case-control study was performed, comparing transradial neuroendovascular procedures in adolescents (age range, 10-18 years) with an age- and procedure-matched cohort of transfemoral neuroendovascular procedures. Clinical and procedural details, including type of procedure, conversion rate, fluoroscopy time, radiation dose, complications, and readmissions, were reported by descriptive statistics or measures of central tendency and compared using a t test or nonparametric equivalent. A P value < .05 was considered statistically significant.

RESULTS

Twenty adolescents (mean age, 14.6 [SD, 1.7] years, M/F ratio = 9:11) who underwent transradial neuroangiography were compared against 20 adolescents (mean age, 14.4 [SD, 2.1 ] years, M/F ratio = 12:8) who underwent transfemoral neuroangiography. We found no significant difference in procedural success (0% conversion rate), fluoroscopy times (33.7 [SD, 40.2] minutes versus 23.3 [SD, 26.2] minutes, P = .34) and radiation dose (150.9 [SD, 133.7] Gy×cm² and 122.9 [SD, 79.7] Gy×cm,² P = .43) There were 2 self-limiting postprocedural complications in the transradial group. There were no major hemorrhages, need for further interventions, or readmissions in either group.

CONCLUSIONS

The benefits of transradial angiography described for adults can likely be safely extended to adolescents. These are important data before transitioning to smaller children and should be prospectively evaluated in a larger cohort.

Novel combined topical gel of lidocaine-verapamil-nitroglycerin can dilate the radial artery and reduce radial pain during trans-radial angioplasty

Introduction

Radial approach for coronary angioplasty is accepted by many specialists in medical centers around the world. The use of radial access is associated with fewer vascular complications and the same success rate in comparison with traditional femoral access. Radial artery spasm is one of the main concerns in this method. The small size of the radial artery and high density of alpha-1 adrenergic receptors in this artery can accelerate the spasm. The objects of this study were to evaluate whether the combined topical gel of lidocaine–verapamil–nitroglycerin could dilate the radial artery and reduce patient pain and sympathetic response during radial puncture.

Methods

Patients undergoing elective trans-radial angioplasty were randomized to either placebo or therapeutic gel group in single-center, double-blind study. Placebo or therapeutic gel applied 1 cm proximal to the radial styloid process. Radial artery size was measured by ultrasound. Radial pain was reported by the visual analog scale (VAS) and the sympathetic response was assessed by changes in systolic (SBP) and diastolic blood pressure (DBP) and heart rate (HR). The incidence of spasm was defined by the radial artery spasm score.

Results

60 patients (30 patients in each group) participated in this study. A significant increase in the size of the radial artery was observed in the group receiving therapeutic gel compared to the placebo group (mean diameter, mm: 2.95 ± 0.48 vs. 2.54 ± 0.43, p = 0.001; area, cm²: 0.07 vs. 0.05, p = 0.001). During radial puncture, the radial pain intensity was significantly decreased in patients receiving therapeutic gel (4 (1–5) vs. 2 (1–2), p = 0.003). Radial artery spasm didn’t happen in any group.

Conclusion

Based on our results, Pre-procedural administration of combined topical gel of verapamil-nitroglycerin-lidocaine significantly increases the size of the radial artery and effectively reduces the radial pain during radial puncture in patients undergoing trans-radial angioplasty.

Comparison of Mean Fluoroscopic Time and Mean Contrast Volume Used in Patients Undergoing Coronary Angiography by the Transfemoral Versus Transradial Route

Introduction The prolonged fluoroscopic time during coronary angiography results in a higher radiation dose delivered to patients. Similarly, a higher contrast volume used is associated with higher rates of contrast-induced nephropathy. This study was designed to identify the better technique in terms of lesser fluoroscopic time and volume of contrast used during the procedure. Objective To compare mean fluoroscopic time and mean contrast volume used in patients undergoing coronary angiography through the transfemoral versus transradial route. Methods A randomized controlled trial (RCT) was conducted at the department of cardiology, Pakistan Institute of Medical Sciences (PIMS) Islamabad between June 2017 and December 2017. Ninety (n=90) patients planned for coronary angiography between 30 and 70 years of age were enrolled. Patients were randomly allocated to Group A (transfemoral route group) and Group B (transradial route group). Fluoroscopic time (minutes) and contrast volume (milliliters) used were measured in each patient. Results The mean contrast volume used in Group A was 70.4 ml (SD=8.7) and in Group B, it was 90.1 ml (SD=9.8) (P<0.001). The mean fluoroscopic time in Group A was 5.1 min (SD=1.2), and in group B, it was 8.6 min (SD=1.2) (P<0.001). Similar trends were noted when data were stratified with respect to age and gender. Conclusion The mean fluoroscopic time and the mean contrast volume were significantly less in patients where coronary angiography was performed through the transfemoral route than through the transradial route in this study.

The Use of Topical Nitroglycerin to Facilitate Radial Arterial Catheter Insertion in Children: A Randomized Controlled Trial

OBJECTIVES

To determine whether the use of topical nitroglycerin patch increases radial artery diameter and facilitate cannulation in children.

DESIGN

Randomized controlled trial.

SETTING

Cairo University Hospital.

PARTICIPANTS

Children aged 2 to 8 years old scheduled for cardiac surgery.

INTERVENTION

In the nitroglycerin group (n = 20), a gauze-covered, half-sized nitroglycerin patch (5 mg) was applied at the site of radial pulsation 1 hour before induction of anesthesia. In the control group (n = 20), a gauze pad was applied to the bare skin at the site of radial pulsation with no intervention.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the diameter of the radial artery in both limbs using ultrasonography. Other outcomes included the degree of arterial palpability, number of arterial punctures, and incidence of successful first puncture cannulation. The radial artery diameter increased after 30 minutes and 60 minutes compared with the baseline value in the nitroglycerin group in both limbs, whereas no change was reported in the radial artery diameter in the control group. The nitroglycerin group showed a greater incidence of successful first cannulation trial, a fewer number of trials, and a shorter cannulation time compared with the control group. There were no significant hypotensive episodes in any patient.

CONCLUSION

Local application of a half-sized, 5 mg nitroglycerin patch for 60 minutes in children increased the radial artery diameter bilaterally, increased the rate of first trial success, and decreased the time needed for arterial cannulation without significant hypotensive episodes.

Radial artery spasm: reviews and updates

Elective and emergent coronary interventions via transradial access (TRA) are been used increasingly as they carry a reduced risk of complications. Percutaneous coronary intervention via TRA may lead to radial artery spasms (RAS) that may result in prolonged procedure time, cross-over of access site, and other complications. This review article discusses the recent definitions, incidences, pathophysiology, predictive score calculator, efficacy, the safety of the radial cocktails, and treatment of the RAS.

Are cerebral ischaemic complications more likely to occur in elderly patients undergoing transradial non-coronary intervention: A single-centre retrospective review

INTRODUCTION

Transradial artery access (TRA) is an established technique employed by interventional cardiologists for diagnostic and therapeutic coronary interventions. The use of TRA has gained increasing traction amongst interventional radiologists in recent years. In transradial, non-coronary interventions, the aorta has to be traversed. With increasing age, atherosclerotic changes in the aorta posed a theoretical risk of catheter-related emboli. Currently, there is limited literature available on the cerebral ischaemic complication rates in transradial non-coronary interventions.

METHODS

Between November 2015 and December 2017, 150 transradial non-coronary interventions were performed on 95 patients. Intra-procedural, in-hospital, 30-day and 6-month complications (ischaemic stroke, transient ischaemic attack and death, and minor complications, such as puncture site haematoma, pseudoaneurysm, thrombosis, dissection and perforation) were compared between the two age groups (≤65 and >65 years old).

RESULTS

The patients were predominantly male (87.0%) with age ≤65 (N = 69; 46.0%) and age >65 (N = 81; 54.0%). There were no ischaemic strokes at all time points in both groups, except for one case of ischaemic stroke at 6 months in the age ≤65 group(1.4% vs. 0.0%; P = 0.462). On multivariable analysis, age >65 was associated with lower in-hospital death rates (OR 0.251; 95% CI 0.013-3.09), at 30 days (OR 0.608; 95% CI 0.77-4.805) and at 6 months (OR 0.514; 95% CI 0.169-1.558) with no deaths intra-procedurally in both groups. Minor complications include puncture site grade I haematoma formation (2.9% vs. 2.5%; P = 0.999) and pseudoaneurysm (2.9% vs. 0.0%; P = 0.210). In our study, the overall major and minor complications rates are low and no statistically significant difference exists between the two groups.

CONCLUSION

Transradial non-coronary interventions are safe in elderly patients, who are likely to have more atherosclerotic disease of the aorta. Of note, no complication of ischaemic strokes within 30 days of the procedure is documented in all patients.

The Comparison of Traditional Radial Access and Novel Distal Radial Access for Cardiac Catheterization

OBJECTIVES

The traditional radial access (TRA) has been used almost routinely in coronary interventions in our clinic. Recently, we have started to use distal radial artery point as distal radial access (DRA) more frequently. The aim of this study is to compare these techniques (DRA and TRA) in terms of their safety, feasibility, and effectiveness.

BACKGROUND

Recently, the distal transradial access novel techniques have started to be used in coronary interventions, such as the anatomical snuffbox (AS) and DRA.

METHODS

This prospective, randomized study was carried out in a single center. The patients were selected from the catheterization laboratory of Medicana Ankara Hospital, between October 2018 and December 2018. Consecutive patients with TRA (103 patients) and DRA (102 patients) were randomized for coronary intervention.

RESULTS

Successful catheterization was achieved in 99 of 103 (96.1%) patients in the TRA group and in 97 patients of 102 (95.1%) patients in the DRA group. The radial artery spasm was observed in 4 cases in TRA group, whereas no radial artery spasm was seen in DRA group (p < 0.0001). The transradial access time in the DRA group (46.85 ± 2.41 s) lasted longer than the TRA (36.66 ± 5.16 s, p = 0.008).In DRA, hemostasis seems quicker than TRA.

CONCLUSIONS

DRA is feasible and safe for coronary angiography and interventions like TRA. It can be used as an alternative technique.

Comparison of procedural success between two radial sheaths : Comparison of the 6-Fr Glidesheath Slender to 6-Fr standard sheath

BACKGROUND

The most common cause of procedural failure in cardiac catheterization using the transradial approach is radial artery spasm. The aim of this study was to compare the procedural success rate of the 6‑Fr Glidesheath Slender with the 6‑Fr standard sheath in transradial coronary angiography and intervention.

METHODS

Patients who underwent percutaneous coronary angiography via the transradial approach through placement of a 6-Fr Glidesheath Slender or a 6-Fr standard sheath for primary radial access were prospectively enrolled in the study.

RESULTS

The study included 200 cases: 76 patients undergoing percutaneous coronary angiography with the Glidesheath Slender and 124 patients with the standard sheath. Failed procedures were recorded for 19 patients (9.5%), defined as inability to complete the procedure via the primary access. There was no difference in the percentage of failed cases between the Glidesheath Slender and standard sheath groups (10.5% vs. 8.9%, OR = 1.21, p = 0.8). More cases of spasm were observed in the Glidesheath Slender group compared with the standard sheath group, which was not statistically significant (7.9% vs. 5.7%, OR = 1.43, p = 0.56). Smoking, hyperlipidemia, and age influenced the procedural outcome in the Glidesheath Slender group, while body mass index, sex, and smoking impacted the procedural outcome in the standard sheath group.

CONCLUSION

There is no difference in procedural success rates, as defined by the ability to complete the procedure via primary radial access, between the 6‑Fr Glidesheath Slender and the 6‑Fr standard sheath. Our study suggests that the patient characteristics that elevate the risk of procedural failure for Glidesheath Slender may differ from those for the standard sheath.

Anesthetic ointment only (lidocaine/prilocaine) instead of injectable local lidocaine in trans-radial catheterization: A viable no-needle alternative

OBJECTIVE

The aim of the present study was to assess the level of access site pain in patients undergoing transradial coronary catheterization by using topical application of an anesthetic ointment (lidocaine/prilocaine-AO) compared to standard local anesthesia (LA) by means of injectable lidocaine.

METHODS

We prospectively studied 444 patients undergoing elective trans-radial coronary angiography. The quality of analgesia was assessed using a visual analogue scale (VAS) immediately after the puncture and 30 min after the removal of the sheath. The number and duration of attempts before successful sheath insertion, as well as artery spasm, were compared between the two groups.

RESULTS

Pain levels measured by VAS were found to be similar between the two groups during sheath insertion (VAS: AO: 4.84 ± 1.0 vs 4.82 ± 1.2, P = NS), as well as 30 min after sheath removal (VAS: AO: 0.07 ± 0.5 vs LA: 0.15 ± 0.6, P = NS). The time to obtain radial access was also not affected by the use of anesthetic ointment (AO: 62.24 ± 25.7 s vs LA: 64.04 ± 18.78 sec, P = NS). The rate of clinical or angiographic radial artery spasm was similar (8-10%) between the groups (P = NS) CONCLUSION: Use of a local anesthetic ointment, versus injectable lidocaine, in trans-radial cardiac catheterization as means of local anesthesia, was found to be equally effective in terms of pain, artery spasm, or artery cannulation speed.

Learning curve estimation in medical devices and procedures: hierarchical modeling

In the use of medical device procedures, learning effects have been shown to be a critical component of medical device safety surveillance. To support their estimation of these effects, we evaluated multiple methods for modeling these rates within a complex simulated dataset representing patients treated by physicians clustered within institutions. We employed unique modeling for the learning curves to incorporate the learning hierarchy between institution and physicians and then modeled them within established methods that work with hierarchical data such as generalized estimating equations (GEE) and generalized linear mixed effect models. We found that both methods performed well, but that the GEE may have some advantages over the generalized linear mixed effect models for ease of modeling and a substantially lower rate of model convergence failures. We then focused more on using GEE and performed a separate simulation to vary the shape of the learning curve as well as employed various smoothing methods to the plots. We concluded that while both hierarchical methods can be used with our mathematical modeling of the learning curve, the GEE tended to perform better across multiple simulated scenarios in order to accurately model the learning effect as a function of physician and hospital hierarchical data in the use of a novel medical device. We found that the choice of shape used to produce the 'learning-free' dataset would be dataset specific, while the choice of smoothing method was negligibly different from one another. This was an important application to understand how best to fit this unique learning curve function for hierarchical physician and hospital data. Copyright © 2017 John Wiley & Sons, Ltd.

Effectiveness of Handmade "Jacky-Like Catheter" As a Single Multipurpose Catheter in Transradial Coronary Angiography: A Randomized Comparison With Conventional Two-Catheter Strategy

OBJECTIVE

To investigate safety and efficacy of specialized hand-modified "Jacky-Like" catheter (JLC) as a single dual-purpose catheter in transradial coronary angiography.

METHODS

Patients over 18 years undergoing diagnostic CAG through right radial artery (RRA) were prospectively enrolled. Procedures were performed with a single JLC modified from a left Judkins (JL) 3.5 catheter or by using 2-catheter approach (2C). Procedures with coronary artery bypass grafts or ventricular angiographies were excluded from the study. Three hundred and eighty-seven transradial procedures were performed successfully. One hundred and ninety-four procedures were performed with 2C and 193 procedures with a JLC. Inability to use intended catheters, total fluoroscopic time in minutes, the consumption of contrast medium in milliliter, development of radial artery spasm (RAS), and radial artery occlusion (RAO) were evaluated.

RESULTS

In the 2C group, angiography was successfully performed on the RCA of 191 patients (98.9%) and on LCA in 192 patients (99.4%). In the JLC group, angiography was successfully performed on the RCA and LCA of 193 (99.4%) and 174 (89.6%) patients, respectively. Utilization of supplemental catheters was significantly greater in the JLC group (21; 10.8%) versus the 2C group (3; 1.5% P = 0.001). Mean fluoroscopy time was shorter in the JLC group (2.0 ± 2.3 min vs. 2.3 ± 1.5 min; P = 0.043). Mean procedure time was also decreased with JLC but did not reach statistical significance (5.7 ± 3.1 min vs. 6.2 ± 2.5 min; P = 0.081). When additional time for reshaping the JLC was not taken into account, mean procedure time was significantly decreased in the JLC group (5.6 ± 2.9 min vs. 6.2 ± 2.4 min; P = 0.031). There was a trend toward lower incidence of consumption of contrast medium in the 2C group (49 ± 13 mL vs. 52 ± 18 mL; P = 0.061). RAS was observed more frequently in the 2C group (11.3% vs. 21.7%, P = 0.005). There was a trend toward high incidence of RAO in the 2C group (4.1 vs. 8.3% P = 0.064).

CONCLUSION

In transradial procedures from RRA, a JLC catheter can be very effective when dedicated dual-purpose catheter is not available.

Radial access for cerebrovascular procedures: Case report and technical note

BACKGROUND

Advantages of radial access over brachial/axillary or femoral access have been well described for several decades and include decreased cost, patient preference, and decreased major access site complications. Despite these advantages, radial access is rarely employed or even considered for neurointerventional procedures. This attitude should be reconsidered given several recent large, randomized, controlled trials from the cardiovascular literature proving that radial access is associated with statistically lower costs, decreased incidence of myocardial infarctions, strokes, and even decreased mortality. Radial access is now considered the standard of care for percutaneous coronary interventions in most US centers. Although radial access has been described for neurovascular procedures in the past, overall experience is limited. The two major challenges are the unique anatomy required to access the cerebral vasculature given very acute angles between the arm and craniocervical vessels and limitations in available technology.

METHODS

We present a simplified approach to radial access for cerebrovascular procedures and provide a concise step-by-step approach for patient selection, ultrasound-guided single-wall access, recommended catheters/wires, and review of patent hemostasis. Additionally, we present a complex cerebrovascular intervention in which standard femoral access was unsuccessful, while radial access was quickly achieved to highlight the importance of familiarity with the radial approach for all neurointerventionalists.

RESULTS

We have found that the learning curve is not too steep and that the radial access approach can be adopted smoothly for a large percentage of diagnostic and interventional neuroradiologic procedures.

CONCLUSIONS

Radial access should be considered in all patients undergoing a cerebrovascular procedure.

Randomized comparison of long and short vascular sheaths in reduction of the operator radiation exposure during uterine artery embolization

OBJECTIVE

To introduce a method in which a long sheath is used instead of the traditional short sheath, to reduce the radiation exposure of operators in uterine artery embolization (UAE).

METHODS

52 patients undergoing UAE were randomly divided into two groups before the procedure: an 11-cm short sheath was used in Group A (n = 25), and a 45-cm-long sheath was used in Group B (n = 27); the 45-cm-long sheath was only partly inserted such that the hub of the sheath was approximately 34 cm caudal to the groin puncture site. All the procedures were standard bilateral UAE operations through unilateral approach. The other parameters of the two groups were kept the same, including the fluoroscopy conditions and the pelvic radiation field size. The thermoluminescent personal dosemeters were attached to the left wrist and left outer side of the thyroid collar of the operator during each operation. The radiation exposure of the operator, procedure duration and fluoroscopy time of each procedure were recorded. Statistical analysis was performed using independent samples t-test.

RESULTS

The radiation exposure of both the left hand and thyroid of the operator was significantly reduced with the long sheath compared with the short sheath (89.5 ± 7.2 μGy vs 186.7 ± 12.6 μGy, p < 0.001, and 54.1 ± 5.5 μGy vs 63.9 ± 7.4 μGy, p < 0.001, respectively). No significant differences were found in the procedure duration and fluoroscopy time between the two groups (p > 0.1).

CONCLUSION

Using a long sheath in UAE could significantly reduce the radiation exposure to the interventionists without extending the procedure duration or fluoroscopy time.

ADVANCES IN KNOWLEDGE

For the first time, we introduce a simple and convenient method to reduce the radiation exposure of the operator in the UAE procedure.

Reperfusion Times for Radial Versus Femoral Access in Patients With ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: Observations From the Cardiac Care Network Provincial Primary PCI Registry

BACKGROUND

Radial access is associated with less bleeding and vascular complications. However, it may delay reperfusion during primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction.

METHODS AND RESULTS

A provincial database prospectively collected clinical and procedural characteristics for all urgent percutaneous coronary intervention procedures performed between June 2010 and September 2011 in Ontario for ST-segment-elevation myocardial infarction, including time of arrival in the catheterization laboratory and time of first balloon inflation. After excluding patients with cardiogenic shock, with previous bypass surgery, or who received fibrinolysis, 2947 patients were included in the analysis. Propensity score matching was used to minimize difference in clinical characteristics between radial and femoral access procedures. Predictors of radial access included younger age and male sex. After propensity score matching, the median time from arrival in the cardiac catheterization laboratory to first balloon was 27 minutes (25th%-75th%, 21-34) for the femoral group and 30 minutes (25th%-75th %, 24-39) for the radial group (P<0.001). When hospitals were stratified based on the proportion of primary percutaneous coronary intervention cases that were performed using radial access, there was no difference in treatment times between radial and femoral access in the tercile of hospitals that used radial access most frequently. There were no significant differences in the rates of death or myocardial infarction at 30 days.

CONCLUSIONS

This contemporary multicenter registry demonstrates that the time to first balloon inflation is slightly longer with radial access than with femoral access, although the 3 minute difference is unlikely to be clinically relevant. There is no difference in treatment times at hospitals that frequently use radial access for primary percutaneous coronary intervention. Short-term mortality and reinfarction rates are similar with radial and femoral access.

Procedural sedation during transradial coronary angiography to prevent spasm

AIM

Radial artery spasm is common during transradial procedures and is the most common cause of procedural failure. The objectives of this study were to assess whether the routine administration of sedation at the beginning of transradial coronary angiography with the use of hydrophilic-coated and smaller sheaths/catheters would reduce the incidence of radial artery spasm.

PATIENTS AND METHODS

Patients undergoing transradial coronary angiography were prospectively randomized to receive midazolam during the procedure or no sedative treatment. The primary endpoint was angiographically confirmed radial artery spasm. Stenosis of the radial artery was measured with a computer-assisted quantification method.

RESULTS

In all, 150 patients were randomized into a treatment group and a control group. Spasm occurred in 15 patients of the treatment group (20 %) versus 16 in the control group (21.3 %). There were no differences between the two groups regarding the incidence of spasm and the distribution of spasm severity (p > 0.05). No significant differences were observed between the two groups in terms of 30-day mortality or repeat hospitalization for any cause (p > 0.05).

CONCLUSION

Routine use of midazolam could not reduce the occurrence of radial artery spasm during transradial coronary angiography.

Feasibility of the Transradial or the Transbrachial Approach in Various Neurointerventional Procedures

Purpose

The generally preferred vascular access for neurointerventional procedures is the transfemoral approach (TFA). In complicated cases such as patients with aortic diseases or tortuous vessels, transradial or transbrachial approaches (TRA or TBA) could be good alternatives. The purpose of this study is to review a single medical center experience using the alternative accesses.

Materials and Methods

We reviewed the medical records of 30 TRA and 10 TBA cases among 2,073 cases treated between January 2010 and July 2013. We reviewed and analyzed the frequency of TRA and TBA, the reason the operator had chosen the TRA or TBA, the category of the procedure, caliber of the sheath, the success rate, and the complications rates.

Results

The most common reason the non-TFA route was chosen was due to the patient's tortuous vascular system (n=24, 60%). The most common category of intervention was balloon angioplasty and/or stent placement (n=18, 45%). The largest caliber of the introducing sheath was 6 Fr in TRA and 7 Fr in TBA. Procedural success was achieved in 37 cases (success rate: 92.5%), and in three cases it failed. Six patients with complications were reported. Among them, four cases of minor complications (10%) occurred. There was no serious complication directly related to the access problem.

Conclusion

Both TRA and TBA can be good alternative access routes when TFA is not appropriate in various neurointervential procedures.

Reduction of occupational radiation dose in staff at the cardiac catheterisation laboratory by protective material placed on the patient

Reducing occupational radiation dose in cardiac catheterisation laboratories is one of the objectives of the radiation protection system because the procedures performed involve high levels of radiation compared with others in health care. Recommendations on protection methods used are referred to different structural types and personal protection tools. In this work, the effectiveness of a shielding drape above the patient in different geometric shapes for a standard procedure in interventional cardiology was evaluated. Values of personal dose equivalent Hp(10) obtained simultaneously with three active electronic semiconductor dosemeters located at the usual position of staff and at the C-arm have been used to show the usefulness of the shielding drape.

Comparative efficacy and safety of the left versus right radial approach for percutaneous coronary procedures: a meta-analysis including 6870 patients

The radial approach is widely used in the treatment of patients with coronary artery disease. We conducted a meta-analysis of published results on the efficacy and safety of the left and right radial approaches in patients undergoing percutaneous coronary procedures. A systematic search of reference databases was conducted, and data from 14 randomized controlled trials involving 6870 participants were analyzed. The left radial approach was associated with significant reductions in fluoroscopy time [standardized mean difference (SMD)=-0.14, 95% confidence interval (CI)=-0.19 to -0.09; P<0.00001] and contrast volume (SMD=-0.07, 95%CI=-0.12 to -0.02; P=0.009). There were no significant differences in rate of procedural failure of the left and the right radial approaches [risk ratios (RR)=0.98; 95%CI=0.77-1.25; P=0.88] or procedural time (SMD=-0.05, 95%CI=0.17-0.06; P=0.38). Tortuosity of the subclavian artery (RR=0.27, 95%CI=0.14-0.50; P<0.0001) was reported more frequently with the right radial approach. A greater number of catheters were used with the left than with the right radial approach (SMD=0.25, 95%CI=0.04-0.46; P=0.02). We conclude that the left radial approach is as safe as the right radial approach, and that the left radial approach should be recommended for use in percutaneous coronary procedures, especially in percutaneous coronary angiograms.

Transradial versus Transfemoral Approach in Coronary Angiography: A Matched Pair Analysis of Cath Lab Equipment Costs

Introduction

There is an ongoing struggle to understand the potential economic benefits that radial access may offer. Cost savings are thought to primarily occur after the procedure. The aim of our study was to analyze cath lab expenses resulting from transradial (TRA) and transfemoral approaches (TFA).

Methods

A total of n = 1890 matched pairs of patients were analyzed. A traditional Judkins catheter strategy was pursued for coronary angiography. Three large databases were merged to collect and compare procedural data as material, medication costs and fluoroscopy time.

Results

Compared to TFA diagnostic catheterization from TRA was associated with significantly lower procedural costs (€181.0 versus €167.5; p<0.001). Extra costs in TFA were primarily produced by frequent use of vascular closure devices (VCDs) in 86% of patients. However, the potential saving amount related to VCD use was only partly realized due to the higher number of extra catheters (0.53 ± 0.9 versus 0.23 ± 0.6; p<0.001) and hydrophilic guidewires (0.088 ± 0.3 versus 0.014 ± 0.1; p<0.001) used in TRA. Weak correlations were observed between the total number of cases and fluoroscopy time (r = −0.13; p<0.001) as well as material costs (r = 0.31; p<0.001).

Conclusions

Significant cost savings can be realized by TRA at the procedural level even when adhering to a conventional Judkins catheter strategy. Hydrophilic guidewires and additional catheters are the main cost drivers in TRA. In contrast to fluoroscopy time material costs steadily increase during the early stage of the TRA learning curve.

Rebirth of left radial artery access: could this be the 'right' radial artery?

Cardiac catheterization has several risks, notably which include bleeding, stroke and death. The transradial (TR) approach to catheterization is associated with a lower bleeding risk. The right radial approach is the default method in most laboratories and the left radial artery (LRA) serves as the bail-out approach. This article discusses the advantages and disadvantages of transfemoral and TR access routes. The authors envisage an increased adoption of the LRA approach, due to the anatomical superiority and ease of catheter engagement afforded by this approach. The authors discuss ways to increase operator ease for LRA in the laboratory and propose a novel way to improve LRA work-flow.

The Transradial Learning Curve and Volume-Outcome Relationship

This article discusses how learning curves correlate with learning in transradial catheterization. Although learning curves exist in the conversion to transradial approaches, current percutaneous coronary intervention (PCI) procedures are so safe that only surrogate end points such as contrast usage and x-ray exposure show learning effects. Using these surrogates, a learning curve of 30 to 50 patients seems typical to transition cardiologists from transfemoral to transradial PCI. This transition occurs with the immediate benefit of reduced vascular complications and bleeding and without loss of overall procedural success. These measures of safety during learning exist despite difference of procedural volumes.

The learning curve for transradial percutaneous coronary intervention among operators in the United States: a study from the National Cardiovascular Data Registry

BACKGROUND

Adoption of transradial percutaneous coronary intervention (TRI) in the United States is low and may be related to challenges learning the technique. We examined the relationships between operator TRI volume and procedural metrics and outcomes.

METHODS AND RESULTS

We used CathPCI Registry data from July 2009 to December 2012 to identify new radial operators, defined by an exclusively femoral percutaneous coronary intervention approach for 6 months after their first percutaneous coronary intervention in the database and ≥15 total TRIs thereafter. Primary outcomes of fluoroscopy time, contrast volume, and procedure success were chosen as markers of technical proficiency. Secondary outcomes included in-hospital mortality, bleeding, and vascular complications. Adjusted outcomes were analyzed by using operator TRI experience as a continuous variable with generalized linear mixed models. Among 54 561 TRI procedures performed at 704 sites, 942 operators performed 1 to 10 procedures, 942 operators performed 11 to 50 procedures, 375 operators performed 51 to 100 procedures, and 148 operators performed 101 to 200 procedures. As radial caseload increased, more TRIs were performed in women, in patients presenting with ST-segment elevation myocardial infarction, and for emergency indications. Decreased fluoroscopy time and contrast use were nonlinearly associated with greater operator TRI experience, with faster reductions observed for newer (<30-50 cases) compared with more experienced (>30-50 cases) operators. Procedure success was high, whereas mortality, bleeding, and vascular complications remained low across TRI volumes.

CONCLUSIONS

As operator TRI volume increases, higher-risk patients are chosen for TRI. Despite this, operator proficiency improves with greater TRI experience, and safety is maintained. The threshold to overcome the learning curve appears to be approximately 30 to 50 cases.

Need for prophylactic application of verapamil in transradial coronary procedures: a randomized trial. The VITRIOL (is Verapamil In TransRadial Interventions OmittabLe?) trial

BACKGROUND

Verapamil is traditionally applied prophylactically in transradial procedures to prevent radial artery spasm. However, verapamil may have side effects and is contraindicated in some clinical settings.

METHODS AND RESULTS

During an investigator-initiated, randomized, double-blind trial, we evaluated the need for preventive verapamil administration. After vascular access was established, patients received either 5 mg verapamil (n=297) or placebo (n=294). We compared the rate of access site conversions as primary end point using a superiority margin of 5%. Occurrence of code breaks (composite of conversions and unplanned use of verapamil), overall verapamil use, procedural and fluoroscopic times, contrast volume, and subjective pain were investigated as secondary end points. The rate of access site conversions was not different in the 2 arms (placebo 1.7% versus verapamil 0.7%, P=0.28, difference 1.0%, 95% CI for the difference -1.1% to 3.3%). Proportion of code breaks was similar in the 2 groups (3.4% versus 1.3%, P=0.11), whereas overall verapamil use was markedly lower in the placebo arm (2.0% versus 100%, P<0.0001). Procedural time (median [IQR] 16.0 minutes [9.0 to 30.0 minutes] versus 17.0 minutes [10.0 to 31.0 minutes], P=0.37), fluoroscopic time (4.4 minutes [2.1 to 9.6 minutes] versus 4.8 minutes [2.4 to 10.7 minutes], P=0.28), contrast volume (72.5 mL [48.0 to 146.0 mL] versus 75.5 mL [47.0 to 156.5 mL], P=0.74), and pain score (P for trend=0.12) were comparable in the 2 groups.

CONCLUSIONS

The preventive use of verapamil may be unnecessary for transradial procedures. The omission of prophylactic verapamil may not only reduce the rate of potential complications related to the drug but also allow the safe extension of the transradial method to those with contraindications to verapamil.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01402427.

Operator learning curve for transradial percutaneous coronary interventions: implications for the initiation of a transradial access program in contemporary US practice

OBJECTIVES

Our study aimed to assess the characteristics and outcomes of transfemoral approach (TFA) versus the initial steps of a transradial approach (TRA) program and to assess the learning curve of TRA in contemporary, US practice.

BACKGROUND

When compared to TFA, TRA has been shown to lower bleeding and vascular complications during percutaneous coronary intervention (PCI). However, use of TRA is still low. There are limited data regarding the characteristics of TRA learning curve, especially in an era with designated TRA equipment.

METHODS

Consecutive patients undergoing PCI in a single US center were divided into two cohorts according to vascular access approach: the last 250 TFA patients prior to the establishment of a TRA program and the initial 239 TRA patients following the establishment of a TRA program. Subgroup analysis of the TRA group, which was divided into five sequential case groups of 50 cases per group, was performed in order to assess TRA learning curve.

RESULTS

Overall, the baseline characteristics of TFA vs. TRA groups were comparable. Fluoroscopy time was significantly longer during TRA procedures (18±11 vs. 15±8min, respectively, p=0.002); however, contrast use was lower during TRA procedures (161±72 vs. 180±63ml, respectively, p=0.002). In-hospital outcomes were similar between the two groups, with low frequencies of mortality, myocardial infarction, and stent thrombosis. Subanalysis of TRA group for learning curve assessment showed no major differences in patient demographics among the five subgroups. In the initial cases, more PCI was performed among non-acute cases (62% in patients 1-50 vs. 8-27% in patients 51-239, p<0.001). Despite these differences, characteristics of the treated vessels were similar between groups. There was no significant change in fluoroscopy time or in the amount of iodinated contrast volume delivered. Similarly, no differences in procedural, in-hospital, and long-term outcomes were documented.

CONCLUSIONS

Adopting TRA as a default is feasible for high-volume operators without significant learning curve effects.

Carotid Artery Stenting: Operator and Institutional Learning Curves

Despite rapid growth in the frequency that carotid artery stenting (CAS) is performed, there remain concerns regarding the steep learning curve associated with this procedure. This article reviews the evidence base supporting operator and institutional CAS learning curves and discusses their implications for the establishment and maintenance of competencies. Attempts are made to delineate minimum volume thresholds to attain these goals and means to enhance procedural safety without compromising patient access.

Comparison of a safety strategy using transradial access and dual-axis rotational coronary angiography with transfemoral access and standard coronary angiography

OBJECTIVES

We sought to investigate the radiation exposure and contrast utilization associated with using a strategy of transradial access and rotational angiography (radial-DARCA) compared to the traditional approach of transfemoral access and standard angiography (femoral-SA).

BACKGROUND

There is an increased focus on optimizing patient safety during cardiac catheterization procedures. Professional guidelines have highlighted physician responsibility to minimize radiation doses and contrast volume. Dual axis rotational coronary angiography (DARCA) is the most recently investigated type of rotational angiography. This new technique permits complete visualization of the left or right coronary tree with a single injection, and is felt to reduce contrast and radiation exposure.

METHODS

A total of 56 consecutive patients who underwent radial-DARCA were identified. From the same time period, an age- and gender-matched group of 61 patients who had femoral-SA were selected for comparison. Total volume of contrast agent used, fluoroscopy time, and 2 measures of radiation dose (dose area product and air kerma) were recorded for each group.

RESULTS

Mean contrast agent use and patient radiation exposure of the radial-DARCA group were significantly less than that of the femoral-SA group. There was no significant difference in fluoroscopy time between the 2 groups.

CONCLUSIONS

Physicians can successfully employ an innovative safety strategy of transradial access combined with DARCA that is feasible and is associated with lower radiation doses and contrast volume than femoral artery access and traditional coronary angiography approach.

Reduction in operator radiation exposure during transradial catheterization and intervention using a simple lead drape

BACKGROUND

Transradial access for cardiac catheterization and intervention is a recognized method for reducing complications and improving patient comfort. However, there are concerns over possible increased operator radiation exposure. We tested the hypothesis that a simple lead drape would reduce operator exposure in transradial procedures.

METHODS

Patients undergoing either diagnostic or interventional procedures using transradial access were assigned in an alternating manner to the use of a 0.5-mm lead apron across the patient's abdomen in addition to standard operator protection. Patients were divided into 4 groups: (left enhanced shielding vs left standard shielding; right enhanced shielding vs right standard shielding). Dosimeters were taped to the primary and secondary operators' left wrist and outside the thyroid guard. The operator exposure was measured for each site on every case in centigray.

RESULTS

In standard shielded patients, there was no increase in operator exposure between the left and right approach patients at any measurement site. Measured exposure was reduced with enhanced shielding at all dosimeter sites except the secondary operator's collar (both left and right) and the primary operator's collar from the right. There was no significant difference in fluoroscopy, air kerma, or dose area product between standard and enhanced shielded patients.

CONCLUSIONS

The use of a lead drape reduces the rate of operator radiation exposure at multiple measurement sites. Use of the left radial approach was not associated with an increase in operator exposure compared with the right radial approach.

Incidence and predictors of radial artery spasm at the beginning of a transradial coronary procedure

OBJECTIVES

Our aim was to establish the frequency of radial artery spasm (RAS) and its predictors at the beginning of a transradial approach (TRA).

METHODS

This was a single-center prospective study. A total of 1,722 consecutive patients undergoing their first transradial coronary procedure were recruited. After radial artery puncture, a hydrophilic sheath was used to complete arterial puncture, then 500 μg glycerol trinitrate and 2.5 mg verapamil were injected into radial artery along the sheath. After retrograde radial arteriography spasm was defined angiographically as a stenosis greater than 25%. Patient demographics, procedural data such as total procedural duration, the number of catheters and guidewires used, the amount of contrast media usage, dose area product (DAP) and fluoroscopy time, and vascular complications were recorded.

RESULTS

The overall spasm incidence was 10.3%. The procedural success rate was lower in patients with spasm than in patients without spasm (80% vs. 95.7%, P < 0.001). The patients with spasm were older (mean age 63.9 ± 9.4 years vs. 60.0 ± 11.2 years, P < 0.001) and more commonly female (51.3% vs. 34.4%, P < 0.001). Spasm was more common in hypertensive patients (66% vs. 56%, P < 0.009). Surprisingly, smoking was less common in patients with spasm (17% vs. 29%, P < 0.001). Multiple logistic regression analysis showed that female gender (OR = 1,524, 95% CI: 1.033-2.248, P = 0.034) was the only independent predictor of RAS at the beginning of the procedure.

CONCLUSIONS

The incidence of RAS was 10,3%, and female gender was the sole independent predictor of RAS at the very beginning of the procedure in patients undergoing a TRA.

Comparison between transradial and transfemoral percutaneous coronary intervention in acute ST-elevation myocardial infarction

Transradial (TR) access is increasingly being used in percutaneous coronary intervention (PCI). However, its role in PCI for ST-segment elevation myocardial infarction remains controversial because of concerns of procedural complexity adversely affecting the promptness of reperfusion. In this study, 150 consecutive patients who underwent PCI for acute ST-segment elevation myocardial infarction over a period of 24 months were prospectively evaluated; 46 had TR access (31%) and 104 (69%) had transfemoral (TF) access. All patients received thienopyridines, aspirin, and heparin per routine management. There were no significant differences between the TR access and TF access groups with respect to age (62.2 ± 11.6 vs 64.7 ± 14.1, p = 0.28), gender (76.1% vs 72.1% men, p = 0.69), or incidence of diabetes (23.9% vs 26.9%, p = 0.84). The TR and TF access groups were comparable with respect to door-to-balloon time (79.2 ± 32.3 vs 86.8 ± 51.8 minutes, p = 0.67) and amount of contrast used (190.5 ± 101.5 vs 172.2 ± 81.7 ml, p = 0.24). Total fluoroscopy time was longer in the TR access group compared to the TF access group (21.7 ± 12.7 vs 14.4 ± 10.4 minutes, p <0.0001). Postprocedural Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow was comparable for the 2 groups (87% for the TF group and 96% for the TR group, p = 0.15). There were no vascular complications in the TR access group compared to the TF access group (0% vs 5.8%, p = 0.18). In conclusion, this single-center observational study shows that TR access for PCI in STEMI is feasible and that it has fewer vascular complications and shorter length of hospital stay than the TF approach.

Impact of access site selection and operator expertise on radiation exposure; a controlled prospective study

BACKGROUND

Published data relating to arterial access site selection and radiation exposure during coronary procedures suggest radial access may lead to increased radiation exposure, but this is based on poorly controlled studies. We sought to measure radiation exposure to patients and operators during elective coronary angiography (CA) according to access site, with other procedure related variables controlled for. We also investigated the specific effect of operator expertise in relation to radiation exposure.

METHODS

100 consecutive patients undergoing first time elective CA were recruited prospectively. An expert transradial (TR) and an expert transfemoral (TF) operator performed 25 cases each via their default route. A trainee cardiologist with intermediate experience in both access sites performed 25 cases via each route. Angiographic projections were standardised and optimised radiation protection was utilised for all procedures. The primary endpoints were operator and patient exposure, quantified by effective dose (ED) and dose area product (DAP) respectively. Secondary endpoints included fluoroscopy time (FT) and time to patient ambulation.

RESULTS

The trainee operator recorded higher values for radiation exposure in radial and femoral cases when compared to the expert operators. There were no significant differences in radiation exposure during CA to operator or patient according to access site when standardised by operator experience. For the trainee, ED for TR and TF procedures was 8.8 ± 4.3 μSv and 8.5 ± 6.5 μSv (P = .86) and DAP was 25.4 ± 4.8 Gycm(2) vs 25.2 ± 8.3 Gycm(2) (P = .9). For the expert TR and TF operators, ED was 6.4 ± 4.7 μSv vs 6.1 ± 5.6 μSv (P = .85) and DAP was 21.7 ± 6.5 Gycm(2) vs 22.4 ± 8.0 Gycm(2), (P = .74). There was no significant difference in FT in relation to access site. Time to ambulation was significantly longer with TF access.

CONCLUSION

The use of TR access has no adverse effect on radiation exposure or FT for diagnostic CA, but does allow for quicker ambulation compared to TF access. The magnitude of radiation exposure is related to operator expertise for both access sites. The results of previous studies reflect the effect of uncontrolled patient and operator variables and not access site selection.

Direct vasodilation by transdermal administration of nitroglycerin: preliminary, randomized, placebo-controlled trial of nitroglycerin skin spray for premedication before artery puncture

PURPOSE

Transdermal administration of nitroglycerin (NTG) before arterial puncture may improve puncture success. The objective of this study was to evaluate the vasodilation effect of NTG skin spray on brachial arteries.

MATERIALS AND METHODS

We recruited 10 healthy volunteers. On different days and in random order we sprayed their skin above the right or left brachial artery with a solution containing 0.3 mg NTG or above the right brachial artery with physiological saline. A radiologist ultrasonographically measured the cross-sectional area of right brachial artery before and at 5-min intervals for up to 25 min after spraying and calculated the rate of increase of the area.

RESULTS

The average vasodilation rate after spraying with NTG above the right brachial arteries of 10 volunteers was 16.4% at 5 min, 23.6% at 10 min, 19.6% at 15 min, and 16.5% at 20 min; spraying with NTG above the left brachial artery or with physiological saline alone elicited few changes. The vasodilation rate 10 min after spraying with NTG above the right brachial artery was significantly higher than for control groups (P < 0.001).

CONCLUSIONS

Transdermal application of NTG spray dilated the targeted brachial artery. This technique may be a good premedication before artery puncture.