Adoption of Routine Ultrasound Guidance for Femoral Arterial Access for Cardiac Catheterization

Abstract: Background. A randomized controlled trial published in 2010 demonstrated that ultrasound-guided femoral artery access for coronary angiography was faster and associated with fewer vascular complications than conventional fluoroscopic-guided access. The landscape of ultrasound use among contemporary interventional cardiologists is unknown. Methods. We sought to describe current knowledge, attitudes, and practices regarding ultrasound use among interventional cardiologists using an online survey. The questionnaire unfolded in phases, initially attempting to define current attitudes and then testing whether or not attitudes were adjustable after summarizing compelling research supporting the use of ultrasound-guided access. Results. Sixty-eight responses were received (60.7%). Only 13.3% reported using ultrasound routinely despite widespread availability and technical expertise. The majority of respondents believed ultrasound use to be slower but safer than access by palpation alone. There was no significant association between age (P=.70) or annual case volume (P=.11) and baseline ultrasound use. After examining the results of a supporting clinical trial, 42.6% said ultrasound should be used routinely, but only 17.6% said they would adopt the technique. Younger operators tended to affirm routine ultrasound adoption after reading the trial summary more often than older respondents, although this did not reach statistical significance (relative risk = 1.8; P=.30). Conclusions. Routine ultrasound-guided femoral artery access and awareness of its validating evidence is uncommon among current interventional cardiologists; exposure to compelling data had minimal impact on respondents’ willingness to change practice. 

J INVASIVE CARDIOL 2016;28(8):311-314

Key words: femoral access, ultrasound guidance

Use of fluoroscopy to confirm landmarks prior to femoral artery puncture has been shown to reduce inappropriately located access points in some retrospective and prospective randomized trials, but has had limited benefits in another trial.^1-4 On the other hand, the use of ultrasound has been shown to reduce case time and complication rates in cardiac catheterization and in large-bore femoral artery access for other vascular procedures, particularly in patients with difficult anatomy.^5-7 The Femoral Arterial Access with Ultrasound Trial (FAUST) randomized 1004 patients undergoing coronary angiography via the femoral approach to either fluoroscopic or ultrasound guidance. Compared with fluoroscopic guidance, ultrasound improved first-pass success rates (83% vs 46%; P<.001), reduced attempts (1.3 vs 3.0; P<.001), reduced median time to access (136 seconds vs 148 seconds; P=.01), and reduced vascular complications (1.4% vs 3.4%; P=.04).⁵ Although adoption of fluoroscopy is now widespread, utilization of ultrasound has been limited. To date, there are no reliable reports of the prevalence of ultrasound use or why it may not be applied despite a randomized trial supporting its efficiency and safety profile. In this study, we attempt to assess current knowledge, attitudes, and practices regarding routine use of ultrasound to gain femoral arterial access for cardiac catheterization.

Methods

A 16-question survey (Appendix A) was disseminated to specialists in interventional cardiology via email using an internet-based data collection system. Cardiologists were identified using a private research email listserv and via additional personal contacts and included cardiologists throughout the United States, but focused on the southern California region. The questionnaire was designed with separate webpages grouping pre-test and post-test answers. The survey asked an initial set of questions about baseline attitudes and practices, then interjected a single page summarizing the results of the FAUST trial along with a link to the full article. Two post-test questions attempted to assess the impact of this trial’s results on attitudes toward ultrasound use. 

Respondents were blinded to each other’s answers, and the results were aggregated and de-identified for analysis. Descriptive statistics and tests for agreement were reported using STATA version 12.1 or later (StataCorp). The student’s t-test and Fisher’s exact test were used to assess for differences between groups and among users and non-users in terms of baseline characteristics and individual responses to the questionnaire. The study was reviewed and approved by the institutional review board of the University of California, Los Angeles Medical Center in Los Angeles, California.  

Results

Baseline characteristics. Of the 112 cardiologists that were contacted via email, 68 (60.7%) responded to the survey. The majority of participants (85.3%) had dedicated training in interventional cardiology with a median of 7 years experience in the field (Tables 1 and 2). Respondents performed a high number of percutaneous coronary interventions (PCI) annually (median, 190), with 1 participant performing only diagnostic catheterization. The majority of cases (89.7%) were performed via femoral access, but with a broad distribution (Figure 1).

Pre-test results. Only 8/68 (13.3%) reported using ultrasound routinely, despite widespread “readily available” ultrasound equipment in 88.2% of labs and high self-reported comfort (82.8%) with the technical aspects of using ultrasound. By contrast, 91.1% used fluoroscopic-guided access routinely. A large majority (79.5%) believed ultrasound-guided access was slower than conventional access and just over one-half of respondents (66.2%) believed ultrasound reduced complication rates. A minority of participants (39.7%) believed that ultrasound use for routine femoral arterial access diminishes one’s ability to access the femoral artery by palpation alone. An even smaller group (11.8%) believed that ultrasound should not be used to train interventional fellows during their training period. There was no significant association between age (P=.70) or annual case volume (P=.11) and baseline ultrasound use or between age (P>.99) or current use (P>.99) and beliefs regarding fellow training.

Post-test results. Following the summary of the FAUST trial results, 42.6% of participants believed that ultrasound guidance should be routinely used, although 17.6% said they would actually change their own practice and start using ultrasound routinely based on the results of the trial (Figures 2-4). There was no association between operator age or baseline PCI volume and belief that ultrasound should be used following trial results, but there was a strong association between baseline use and belief that ultrasound should be used following exposure to the FAUST trial results, with current users affirming routine ultrasound adoption after reading the trial summary (relative risk, 2.36; P=.02). There was no association between baseline variables, including age and willingness to change practice after reading the results of the FAUST trial, with the exception of interventionalists under age 40, who were twice as likely to be willing to alter their practice, although this did not reach statistical significance (relative risk, 1.8; P=.30). 

Discussion

This study offers insight into how new technology and techniques are disseminated and adopted in the field of interventional cardiology. The FAUST trial, a randomized trial published in a respected journal in 2010, demonstrated that ultrasound guidance was safer and faster than conventional arterial access. Yet, few in the survey appeared to be aware of these results; in fact, nearly 80% believed ultrasound to be slower and only one-half believed it to be safer. Moreover, routine use of ultrasound-guided femoral access among current interventional cardiologists was uncommon (13.3%). Exposure to the results of the FAUST trial led 42.6% to say that ultrasound should be used routinely, but only 17.6% of non-users said the trial would actually alter their own practice. In other words, only one-half of those convinced by the evidence actually said they would adopt it.

The reasons for this disconnect are unclear. The vast majority of respondents said they had readily available equipment and technical expertise. Less than one-half of practitioners expressed concern that routine ultrasound use may weaken their ability to access by palpation alone, and an even smaller minority said ultrasound should not be used to train fellows. Alternatively, it is possible that some of the additional findings of the FAUST trial may have cast doubt on ultrasound’s overall efficacy in the minds of some readers. But while the FAUST trial’s primary endpoint, successful common femoral artery cannulation, was similar between groups, a significant reduction in hematomas and faster access time support the routine use of ultrasound. Operators should be aware that ultrasound may lead to higher access points along the femoral artery, and thus technique, including combined use of fluoroscopy, is paramount. Of note, younger respondents trended toward being more willing to modify their practice, although this did not reach statistical significance, suggesting that this group may have more familiarity with assessing and adopting new evidence or that, conversely, it’s simply difficult to alter set ways (“It’s hard to teach an old dog new tricks”). These results mirror research in other fields of medicine suggesting that younger practitioners tend to be early adopters of new innovation.^8,9

Study limitations. The limitations of this study include its small size and survey method, which relied on direct contacts rather than a systematic nationwide sample. As a result, the conclusions may not be representative of a larger, general practice in the United States. However, those surveyed tended to reside in the local region where the FAUST trial was performed (southern California); thus, the lack of awareness of the trial and slow adoption of this technique may be more pronounced throughout the United States as prior social network research suggests that local communities tend to embrace new innovations first.¹⁰ In addition, although considerable thought was put into the summary of the FAUST trial results provided to respondents, one might argue that the language chosen could have swayed responses while accomplishing its goal of brevity; on the other hand, a link to the article itself was provided, allowing subjects to review the data for themselves.

Conclusion

This survey suggests that routine ultrasound-guided femoral artery access is uncommon among current interventional cardiologists, and that despite the existence of compelling evidence, adoption of new techniques is slow for unclear reasons beyond inertia alone. 

References

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2.    Abu-Fadel MS, Sparling JM, Zacharias SJ, et al. Fluoroscopy vs traditional guided femoral arterial access and the use of closure devices: a randomized controlled trial. Catheter Cardiovasc Interv. 2009;74:533-539.

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6.    Dudeck O, Teichgraeber U, Podrabsky P, Lopez Haenninen E, 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;20:363-368.

7.    Arthurs ZM, Starnes BW, Sohn VY, Singh N, Andersen CA. Ultrasound-guided access improves rate of access-related complications for totally percutaneous aortic aneurysm repair. Ann Vasc Surg. 2008;22:736-741.

8.    Berwick DM. Disseminating innovations in health care. JAMA.  2003;289:1969-1975.

9.    Jippes E, Achterkamp MC, Brand PL, Kiewiet DJ, Pols J, van Engelen JM. Disseminating educational innovations in health care practice: training versus social networks. Soc Sci Med. 2010;70:1509-1517.

10.    Kreindler GE, Young HP. Rapid innovation diffusion in social networks. Proc Natl Acad Sci U S A. 2014;111:10881-10888. Epub 2014 Jul 14.

From the Department of Medicine, Division of Cardiology, UCLA Medical Center, Los Angeles, California.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Lee reports speaker’s bureau income from CSI. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted November 30, 2015, provisional acceptance given December 28, 2015, final version accepted March 29, 2016.

Address for correspondence: Dr Michael S. Lee, 100 Medical Plaza, Suite 630, Los Angeles, CA 90095. Email: mslee@mednet.ucla.edu