Ultrasound Guidance for Vascular Access in Patients Undergoing Coronary Angiography Via the Transradial Approach

Abstract: Background. We assessed the value of routine real-time ultrasound (RTUS) guidance to improve transradial access (TRA) for cardiac catheterization. Methods. A prospective, single-center descriptive observational study of patients presenting for cardiac catheterization via the transradial approach. The first phase of the study enrolled 100 consecutive patients who underwent TRA without the assistance of RTUS followed by 100 consecutive patients who underwent TRA using RTUS guidance. The primary outcome measure was time between needle attempts for arterial access and sheath insertion. Results. There were no statistically significant differences in any outcome measures. Median time between commencing needle attempts for arterial access to sheath insertion was 82.5 seconds (interquartile range [IQR], 64-161.5 seconds) with no RTUS guidance vs 84 seconds (IQR, 52.75-122.5 seconds) with RTUS; P=.19. Median number of needle passes through the skin required was 1 (IQR, 1-3) with no RTUS guidance vs 2 (IQR, 1-3) with RTUS; P=.25. Median number of arterial punctures was 1 (IQR, 1-1) with no RTUS guidance vs 1 (IQR, 1-1) with RTUS; P=.21. Conclusion. Routine RTUS guidance to assist in TRA does not significantly improve parameters of successful vascular access among high-volume radial operators. However, RTUS guidance should still be considered in selected cases and among less experienced radial practitioners. 

J INVASIVE CARDIOL 2015;27(3):163-166

Key words: transradial access, ultrasound, coronary angiography, percutaneous coronary intervention 

_____________________________________

Transradial access (TRA) for left heart catheterization, coronary angiography, and percutaneous coronary intervention (PCI) is an established method for vascular access.¹ TRA has grown in popularity, with overall increasing rates of utilization on a world-wide basis, and is associated with fewer complications than other approaches for cardiac catheterization.^2-5 Recent data have also documented overall improved patient outcomes in the acute infarct setting.^6-8 As a result of this body of data, the European Society of Cardiology has released a consensus statement advocating the implementation of a routine default TRA strategy for PCI.⁹ 

Despite the data, a number of potential barriers stand in the way of more universal adoption of TRA. The smaller caliber of the radial artery relative to the femoral or brachial arteries leads to potentially more technical difficulty in successfully obtaining vascular access via the radial approach. Repeated attempts at radial access have been associated with higher rates of vessel spasm and failed TRA.¹⁰ Previous studies outside of the coronary angiography setting have suggested superior success rates at obtaining radial artery access when using real-time ultrasound (RTUS) guidance.¹¹ Limited data also suggest that this may be applicable to the cardiac setting.¹² We therefore sought to assess the effect of using RTUS guidance on successfully obtaining radial artery access for cardiac procedures.

Methods

Patients. In a prospective observational manner (descriptive study design), patients presenting for coronary angiography ± PCI via the TRA approach to University Hospital, London Health Sciences Centre, London, Ontario, Canada were analyzed as part of a quality-assurance project incorporating the introduction of RTUS assistance into our laboratory. Only patients a priori considered suitable for a radial approach were included in the study. Patients who were treated via femoral approach were not included. Using a femoral approach was the only exclusion criteria. During the time of the study, ~50% of the procedures in our lab were performed by a transradial approach. The transradial approach was utilized by radial operators, who utilize the radial access for ~80% of the procedures. Patients presenting with ST-elevation myocardial infarction (STEMI) were not excluded from the study if a radial approach was selected. In fact, the majority of STEMIs in our center are performed via the transradial approach. Ultrasound was not used to stratify patients to access-site location. Since our study was an audit of a quality improvement measure (descriptive observational study), a formal consent was not required as per the Canadian Tri-Council policy statement on Ethical Conduct for Research Involving Humans (TCPS2).¹³ The study was split into two phases (both observational). The first phase was without RTUS assistance and the second phase where RTUS assistance was introduced for routine use as a quality-improvement initiative. To be eligible for a radial procedure in our center, all patients had to have satisfactory ulnar collateral flow demonstrated by the modified Allen’s test.¹⁴ All operators (including the interventional cardiology fellows) were experienced in TRA (>300 cases) and had also performed at least 10 TRA procedures using ultrasound guidance prior to initiation of the study.

Equipment. RTUS was performed using a portable point of care ultrasound console with a linear probe (SonoSite M-Turbo; SonoSite, Inc). Operators were instructed to use the console to provide continuous real-time guidance for obtaining vascular access with a 21 gauge bare-metal puncture needle and 0.021˝ guidewire. A sterile probe cover and sterile ultrasonic gel were used to facilitate real-time guidance for obtaining vascular access. In both groups, following successful access and sheath insertion (5 Fr or 6 Fr, at operator’s discretion), patients received antispasm prophylaxis with intraarterial administration of 2.5 mg verapamil and 200 µg nitroglycerin. All patients were administered intravenous unfractionated heparin at a dose of 2500-5000 U or bivalirudin (bolus and infusion) as per routine practice at our center.

Parameters. The primary outcome measure was the difference in time between obtaining TRA with or without RTUS, with the time of successful access defined by time from commencing needle puncture attempt to sheath insertion. Other outcomes measured were the number of attempts at access (defined as number of times needle passing through the skin), number of needle passes in and out of the artery (without withdrawing the needle from the skin), and overall success rate of TRA to perform the cardiac procedure.

Statistics. The study was a prospective observational quality-improvement assessment project. We set a target of gathering data on 100 consecutive procedures without RTUS guidance to obtain baseline data to be followed by 100 with RTUS guidance. Ultrasound was introduced into our catheterization laboratory in an attempt to improve rates and efficiency of successfully vascular access as a quality-improvement measure. Statistical analysis was performed using Student’s t-test or Wilcoxon signed rank test (parametric and non-parametric distributions, respectively) for comparing continuous variables and Chi-squared test for comparing categorical variables. Significance was defined by a two-tailed P-value of <.05. Unless otherwise stated, variables are described as median ± interquartile range (IQR). Statistical analysis was performed using SAS JMP version 10.0.2.

Results

Two hundred consecutive patients were included in the study. One hundred patients underwent TRA without RTUS guidance followed by 100 patients with RTUS assistance. Baseline characteristics are shown in Table 1 and were not significantly different between groups (including the rates of anterior wall puncture and deliberate counter wall-puncture techniques). There were no statistically significant differences in any of the outcome measures. 

Median time between commencing needle attempts for arterial access to sheath insertion was 82.5 seconds (IQR, 64-161.5 seconds) with no RTUS guidance vs 84 seconds (IQR 52.75-122.5 seconds) with RTUS; P=.19 (Figure 1). Median number of needle passes through the skin required was 1 (IQR, 1-3) with no RTUS guidance vs 2 (IQR, 1-3) with RTUS; P=.25 (Figure 2). Median number of arterial punctures was 1 (IQR, 1-1) with no RTUS guidance vs 1 (IQR, 1-1) with RTUS; P=.21 (Figure 3). 

For the subgroup of patients with a body mass index (BMI) >30 kg/m² (n = 83), there was no significant reduction in the time to sheath insertion with RTUS (79 seconds; IQR, 44-170 seconds) vs no RTUS assistance (82 seconds; IQR, 64-203.5 seconds); P=.28. There was also no significant reduction in the number of needle passes through the skin (P=.52) or number of arterial punctures (P=.08) in this subgroup.

Among women in the study (n = 55), there was no significant improvement in the primary outcome measure with RTUS (85 seconds; IQR, 60-201.5 seconds) vs no RTUS guidance (78 seconds; IQR, 72.5-164 seconds); P=.91. Similarly, there was no advantage of RTUS assistance for vascular access in male patients (81 seconds [IQR, 48-104.7 seconds] vs 86.5 seconds [IQR, 61-171 seconds]; P=.07).

There was a non-significant trend toward reduced symptomatic spasm (13% with no RTUS vs 6% with RTUS; P=.10) and hematoma (12% with no RTUS vs 6% with RTUS; P=.22) with the RTUS guided approach. There were no other documented vascular complications during the study.

Discussion

We performed a study to evaluate the potential usefulness of using RTUS guidance to reduce vascular access times for TRA in cardiac catheterization procedures. The results of our study demonstrate that routine use of RTUS for radial artery access for cardiac procedures has no benefit compared to standard access using palpation. Routine use of RTUS did not have a significant effect on the number of arterial punctures or time required for vascular access. Taking into account the extra time required to set up the ultrasound system for each patient, the total time required for using ultrasound guidance might, in fact, be longer than a standard approach.

Previous data have demonstrated that using routine RTUS guidance for femoral artery access reduced time to arterial access, achieved greater first-pass success rates, and reduced vascular complications.^15,16 With radial access, there is less concern about bleeding and other access-site complications, and this is one of the key advantages of the TRA approach. However, consistent with the reduction in vascular complications in the femoral data described, we observed a trend in our study to less frequent hematoma formation.

Several prior studies have found an improvement in achieving radial access using RTUS in non-cardiac catheterization laboratory settings.¹¹ In these studies, patients were in a critical care, perioperative, or emergency department environment.^17-20 Significant differences in operator experience would have been present, as well as variable patient features, such as low output states and shock, victims of trauma, and the inclusion of pediatric patients. These factors, which would impair arterial palpation, may have led to superior outcomes when RTUS was used. 

An important qualifier regarding our study is that our center is a high-volume radial center (>2000 radial procedures/year); as a result, the operators may have found little incremental value in RTUS guidance given their experience with the radial approach. From our experience, RTUS is a very useful tool for radial artery access when access is difficult and as part of training. It may be that in institutions where radial access is used less frequently, RTUS may be of value during the adoption of this technique, but this remains to be assessed. 

Effect on complications. We observed a trend toward reduced access-site complications and spasm in the RTUS group during the course of the study. This is mechanistically consistent with the trend seen toward fewer passes through the skin in the RTUS group. While this is encouraging, the sample size is too small to make a definitive conclusion on whether RTUS reduces vascular complication rates, and our study was not powered for this endpoint. There were no other vascular complications reported during the study. However, we did not perform routine follow-up ultrasound screening to assess radial artery occlusion rates.

Study limitations. There are several limitations to our study. The sequential two-phase study design could potentially introduce bias if learning the TRA continues during the study. However, our institution is a high-volume radial center and it is unlikely that the initial 100 patient control phase had any effect on operator competence at radial access.  If such learning effect exists, this would favorably affect the RTUS guidance results. We preferred a 2-phase approach over a randomized trial to ensure inclusion of consecutive patients and reduce bias.

Operators were free to choose puncture technique (anterior vs deliberate counter-puncture technique); despite this, the relative rates of each technique were similar in both groups.  Previous data suggest that a deliberate counter-puncture technique can reduce radial access times, but our study was not designed to prospectively assess this endpoint.²¹

We did not perform any follow-up to see if there was an effect on vessel occlusion rates. A meaningful difference in this parameter is unlikely, given the low incidence of radial artery occlusion and lack of difference in the number of attempts required to gain arterial access or the rate of successful access. 

Blinding of operators, patients, and catheterization laboratory staff was not possible. 

Another possibility for the lack of benefit of ultrasound assistance in our study could be partially explained by type II error. This may be related to the small sample size. In order to perform a randomized study looking for a “hard” clinical outcome (for example, symptomatic radial artery occlusion) and assuming a baseline rate of 2% with an absolute risk reduction of 0.5% (25% relative risk reduction), each group would require 10,795 patients (assuming a two-sided test with an alpha of 0.05 and a power of 0.80).

Conclusion

Among high-volume radial operators, RTUS guidance did not improve the time to successful vascular access when performing cardiac procedures by the transradial approach. There was a non-significant trend toward reduced access-site complications and symptomatic spasm with RTUS guidance. Our data suggest that where radial access is being performed by high-volume radial operators, RTUS guidance need only be reserved for selected cases. There is still a potential role for routine RTUS in centers introducing a radial program to lessen the learning curve, although this remains to be established.

Acknowledgments. We would like to thank our research staff, Sabrina Wall, and the nurses in the cardiac catheterization laboratory.

References

1. Caputo RP, Tremmel JA, Rao S, et al. Transradial arterial access for coronary and peripheral procedures: executive summary by the Transradial Committee of the SCAI. Catheter Cardiovasc Interv. 2011;78(6):823-839.
2. Agostoni P, Biondi-Zoccai GG, De Benedictis ML, et al. Radial versus femoral approach for percutaneous coronary diagnostic and interventional procedures: systematic overview and meta-analysis of randomized trials. J Am Coll Cardiol. 2004;44(2):349-356.
3. Chase AJ, Fretz EB, Warburton WP, et al. Association of the arterial access site at angioplasty with transfusion and mortality: the MORTAL study (Mortality benefit Of Reduced Transfusion after percutaneous coronary intervention via the Arm or Leg). Heart. 2008;94(8):1019-1025.
4. Cruden NL, Teh CH, Starkey IR, Newby DE. Reduced vascular complications and length of stay with transradial rescue angioplasty for acute myocardial infarction. Catheter Cardiovasc Interv.  2007;70(5):670-675.
5. Jolly SS, Amlani S, Hamon M, Yusuf S, Mehta SR. Radial versus femoral access for coronary angiography or intervention and the impact on major bleeding and ischemic events: a systematic review and meta-analysis of randomized trials. Am Heart J. 2009;157(1):132-140.
6. Jolly SS, Yusuf S, Cairns J, et al. Radial versus femoral access for coronary angiography and intervention in patients with acute coronary syndromes (RIVAL): a randomised, parallel group, multicentre trial. Lancet. 2011;377(9775):1409-1420.
7. Romagnoli E, Biondi-Zoccai G, Sciahbasi A, et al. Radial versus femoral randomized investigation in ST-segment elevation acute coronary syndrome: the RIFLE-STEACS (Radial Versus Femoral Randomized Investigation in ST-Elevation Acute Coronary Syndrome) study. J Am Coll Cardiol. 2012;60(24):2481-2489.
8. Joyal D, Bertrand OF, Rinfret S, Shimony A, Eisenberg MJ. Meta-analysis of ten trials on the effectiveness of the radial versus the femoral approach in primary percutaneous coronary intervention. Am J Cardiol. 2012;109(6):813-818.
9. Hamon M, Pristipino C, Di Mario C, et al. Consensus document on the radial approach in percutaneous cardiovascular interventions: position paper by the European Association of Percutaneous Cardiovascular Interventions and Working Groups on Acute Cardiac Care and Thrombosis of the European Society of Cardiology. EuroIntervention. 2013;8(11):1242-1251. 
10. Jia DA, Zhou YJ, Shi DM, et al. Incidence and predictors of radial artery spasm during transradial coronary angiography and intervention. Chinese Med J (English Edition). 2010;123(7):843.
11. Shiloh AL, Savel RH, Paulin LM, Eisen LA. Ultrasound-guided catheterization of the radial artery: a systematic review and meta-analysis of randomized controlled trials. Chest. 2011;139(3):524-529.
12. Roberts J, Ardid M, Carr C, Guido R. TCT-395 Ultrasound-guided radial artery access by a non-ultrasound-trained interventional cardiologist improved first-attempt success rates and shortened time for successful radial artery cannulation. J Am Coll Cardiol. 2012;60(17S).
13. Patel J, Movahed A, Reeves W. Electrocardiographic and segmental wall motion abnormalities in pancreatitis mimicking myocardial infarction. Clin Cardiol. 1994;17(9):505-509.
14. Barbeau GR, Arsenault F, Dugas L, Simard S, Larivière MM. Evaluation of the ulnopalmar arterial arches with pulse oximetry and plethysmography: comparison with the Allen’s test in 1010 patients. Am Heart J. 2004;147(3):489-493.
15. Seto AH, Abu-Fadel MS, Sparling JM, et al. Real-time ultrasound guidance facilitates femoral arterial access and reduces vascular complications: FAUST (Femoral Arterial Access With Ultrasound Trial). JACC Cardiovasc Interv. 2010;3(7):751-758.
16. Dudeck O, Teichgraeber U, Podrabsky P, Haenninen EL, Soerensen R, Ricke J. A randomized trial assessing the value of ultrasound-guided puncture of the femoral artery for interventional investigations. Int J Cardiovasc Imaging. 2004;20(5):363-368.
17. Levin PD, Sheinin O, Gozal Y. Use of ultrasound guidance in the insertion of radial artery catheters. Crit Care Med. 2003;31(2):481-484.
18. Schwemmer U, Arzet H, Trautner H, Rauch S, Roewer N, Greim CA. Ultrasound-guided arterial cannulation in infants improves success rate. Euro J Anaesthesiology. 2006;23(06):476-480.
19. Shiver S, Blaivas M, Lyon M. A prospective comparison of ultrasound-guided and blindly placed radial arterial catheters. Academic Emergency Med. 2006;13(12):1275-1279.
20. Ganesh A, Kaye R, Cahill AM, et al. Evaluation of ultrasound-guided radial artery cannulation in children. Pediatric Critical Care Med. 2009;10(1):45-48.
21. Pancholy SB, Sanghvi KA, Patel TM. Radial artery access technique evaluation trial: randomized comparison of seldinger versus modified seldinger technique for arterial access for transradial catheterization. Catheter Cardiovasc Interv. 2012;80(2):288-291.

__________________________________________

From the London Health Sciences Centre and the University of Western Ontario, London, Ontario, Canada.

Funding: This work was supported by The Program of Experimental Medicine in the Department of Medicine, Western University.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted March 28, 2014, provisional acceptance given May 12, 2014, final version accepted August 18, 2014.

Address for correspondence: Dr Shahar Lavi, Director of Interventional Cardiovascular Research, University Hospital, London Health Sciences Centre, 339 Windermere Road, London, Ontario, N6A 5A5. Email: Shahar.Lavi@lhsc.on.ca