Abstract
Despite increasing use of the transradial approach (TRA) for coronary angiography, TRA failure and subsequent access site crossover remain a barrier to TRA adoption. The aim of this study was to elucidate patient and procedural characteristics associated with TRA to transfemoral approach (TFA) crossover, as well as examine TRA to TFA crossover by operator experience over time. This retrospective analysis identified 1600 patients undergoing coronary angiography with possible PCI via TRA by operators with varied TRA experience in an urban tertiary care center from October 2010 to August 2013. Univariate and multivariable logistic regression were used to identify independent predictors of access site crossover, from TRA to TFA, and strength of association is presented as odds ratio (OR) [95% confidence interval]. Access site crossover was noted in 166 patients (10.4%). Multivariable predictors of access site crossover included age >75 years (OR 1.90 [1.23–2.91], p=0.004) and operator experience (OR 2.98 [1.96–4.52], p<0.0001). Less experienced operators (≤5 years TRA experience) had a decrease in access site crossover over time (Quartile 1: 8.9%, Quartile 2: 18.8%, Quartile 3: 16.4%, Quartile 4: 8.6%; p<0.001), which paralleled an increase in the proportion of procedures using initial TRA over time (Quartile 1: 38.0%, Quartile 2: 53.7%, Quartile 3: 54.8%, Quartile 4: 70.3%; p<0.001). Experienced operators (>5 years TRA experience) had no significant change in proportion of access site crossover over time (Quartile 1: 2.8%, Quartile 2: 6.4%, Quartile 3: 5.6%, Quartile 4: 5.8%; p=0.54). In conclusion, rate of access site crossover in the contemporary era is relatively low and can be mitigated with operator experience.
Keywords: transradial, transfemoral, coronary angiography, crossover
A transradial approach (TRA) to coronary angiography and percutaneous coronary intervention (PCI) is associated with decreased bleeding and access site complications, shorter hospital stays, early ambulation, and improved patient comfort when compared to the transfemoral approach (TFA) (1–4). TRA is also associated with decreased mortality in patients presenting with ST-segment elevation myocardial infarction (5–6). Although utilization of TRA is increasing in the United States, the overall prevalence still remains <20% of all procedures (7–8). Anatomical factors that decrease operator adoption and increase the learning curve associated with TRA include access site failure, radial artery spasm, radial and brachial loops, and tortuosity of the innominate trunk. These factors may also lead to increased rate of access site crossover. Access site crossovers can be potentially problematic as it increases procedure duration, radiation exposure, and risk of vascular complications related to multiple sites of access in patients on antiplatelet and antithrombotic therapy. This study aims to detail patient and procedural characteristics associated with access site crossover, from TRA to TFA. This study also aims to examine TRA to TFA crossover by operator experience as utilization of TRA increases over time.
Methods
This is a retrospective study of consecutive patients who underwent a diagnostic coronary angiography with or without PCI using TRA at a tertiary care center from October 2010 to August 2013. Patients who underwent a planned PCI without a diagnostic component were not included. For patients that had more than one procedure using TRA during the study period, only the first chronological procedure was selected. During this study period, transition to the opposite radial or ulnar artery was not routinely performed (n=5) and, therefore, excluded from the study. This study was approved by the institutional review board at New York University School of Medicine and Bellevue Hospital Center.
Approach to coronary angiography and PCI, including access site and type of catheters used, were per individual operator practice. However, during the study period, standard practice was as follows. Conscious sedation was administered prior to local anesthesia with subcutaneous 1% lidocaine. Arterial access was obtained at least 2 cm proximal to the radial styloid process using the Seldinger technique. Once arterial access was obtained, a 5/6 Fr hydrophilic sheath was inserted and a cocktail of 100 μg nitroglycerin, 2.5 mg verapamil, and 2500 U of unfractionated heparin was administered. 5 Fr diagnostic catheters were used to cannulate the coronary arteries, and radial artery angiography was not performed unless the initial wire or catheter could not be passed to the ascending aorta.
Baseline demographic, clinical, and procedural characteristics were abstracted from a review of electronic patient medical records, including cardiac catheterization reports. Operator experience was categorized as those with less (≤5 years) or more (>5 years) TRA experience. The primary outcome of interest was access site crossover defined as crossover from TRA to TFA for any reason (access failure or failure to engage the coronary arteries or perform PCI).
Continuous variables were examined for normality using the Shapiro Wilkes test. Differences in baseline characteristics between patients who did versus those who did not undergo access site crossover were evaluated by independent two sample t-tests for normally distributed continuous variables, Mann-Whitney U test for skewed continuous variables, and test of proportions for categorical variables. Logistic regression was used to determine multivariable predictors of access site crossover, and strength of association is presented as odds ratio (OR) [95% confidence interval]. Proportion of access site crossover was evaluated over the study period by quartiles of time in days (total cohort: quartile 1, day 1 to 202; quartile 2, day 203 to 434; quartile 3, day 435 to 702; quartile 4, day 703 to 1025). Statistical analysis was conducted using the IBM Statistical Package for Social Sciences software version 20 (IBM Corporation, Armonk, NY) and SAS version 9.3 (SAS Institute Inc., Cary, NC). Statistical significance was tested using a 2-sided α level of 0.05.
Results
Of the 1600 patients who met inclusion and exclusion criteria, 166 patients (10.4%) experienced access site crossover crossover. Baseline characteristics of the group that did versus those that did not undergo access site crossover are shown in Table 1. The proportion of female patients >75 years of age did not differ between the crossover versus no crossover groups (7.2% vs. 5.6%, p=0.383).
Table 1.
Baseline characteristics of patients who did versus those who did not undergo access site crossover during transradial coronary angiography.
| Variable | Access Site Crossover | p-value | |
|---|---|---|---|
| Yes (n=166) | No (n=1434) | ||
| Age (years) | 61.6 ± 12.4 | 59.7 ± 11.8 | 0.085 |
| Age >75 years | 31 (18.7%) | 177 (12.3%) | 0.028 |
| Women | 57 (34.3%) | 515 (35.9%) | 0.733 |
| White | 48 (28.9%) | 421 (29.4%) | 0.658 |
| Black | 52 (31.3%) | 489 (34.1%) | |
| Hispanic | 30 (18.1%) | 219 (15.3%) | |
| Asian | 24 (14.5%) | 230 (16.0%) | |
| Other | 12 (7.2%) | 75 (5.2%) | |
| Height (cm) | 167.0 ± 11.3 | 167.5 ± 10.4 | 0.784 |
| Weight (kg) | 80.6 ± 17.4 | 83.1 ± 22.0 | 0.416 |
| Body mass index (kg/m2) | 28.9 ± 5.9 | 29.6 ± 7.4 | 0.589 |
| Hypertension* | 130 (78.3%) | 1081 (75.4%) | 0.445 |
| Hyperlipidemia† | 108 (65.1%) | 869 (60.6%) | 0.276 |
| Diabetes mellitus | 67 (40.4%) | 544 (37.9%) | 0.555 |
| Prior percutaneous coronary intervention | 26 (15.7%) | 284 (19.8%) | 0.215 |
| Prior coronary artery bypass graft surgery | 9 (5.4%) | 64 (4.5%) | 0.555 |
| Peripheral artery disease/aortic aneurysm | 9 (5.4%) | 61 (4.3%) | 0.428 |
| Tobacco use | 0.161 | ||
| Never | 120 (72.3%) | 1116 (77.8%) | |
| Prior use | 13 (7.8%) | 70 (4.9%) | |
| Current use | 33 (19.9%) | 248 (17.3%) | |
Continuous variables are presented as mean ± standard deviation and categorical variables are presented as n (%)
Hypertension was defined as a clinical diagnosis of hypertension (blood pressure >140/90 or on antihypertensive medications)
Hyperlipidemia was defined as a clinical diagnosis of hyperlipidemia or on lipid-lowering agents
Procedural characteristics of access site crossover versus no crossover groups are shown in Table 2. Timing of access site crossover in the total cohort and by operator experience is shown in Table 3. Of the patients who did undergo access site crossover, 23 (13.9%) were primarily due to radial artery spasm.
Table 2.
Procedural characteristics of patients who did versus those who did not undergo access site crossover during transradial coronary angiography.
| Variable | Access Site Crossover | p-value | |
|---|---|---|---|
| Yes (n=166) | No (n=1434) | ||
| Right-sided access | 160 (96.4%) | 1358 (94.7%) | 0.457 |
| Attending operators with ≤5 years of transradial experience | 137 (82.5%) | 900 (62.8%) | <0.001 |
| Mean number of catheters used to cannulate right coronary artery | 1.57 ± 0.76 | 1.12 ± 0.40 | <0.001 |
| Mean number of catheters used to cannulate left coronary artery | 1.85 ± 1.24 | 1.16 ± 0.52 | <0.001 |
| Mean number of guide catheters used (PCI patients) | 1.40 ± 0.67 | 1.19 ± 0.52 | 0.003 |
| Contrast used during diagnostic angiography (mL) | 96 ± 48 | 73 ± 54 | <0.001 |
| Contrast used during entire procedure (PCI patients) | 245 ± 112 | 195 ± 81 | 0.001 |
PCI = percutaneous coronary intervention
Continuous variables are presented as mean ± standard deviation and categorical variables are presented as n (%)
Table 3.
Timing of access site crossover
| Variable | Total (n=166) | Operators with ≤ 5 years TRA experience (n=137) | Operators with >5 years TRA experience (n=29) | p-value |
|---|---|---|---|---|
| Inability to cannulate the radial artery | 47 (28.3%) | 32 (23.4%) | 15 (51.7%) | 0.003 |
| Inability to cannulate any coronary artery (pre-angiography) | 51 (30.7%) | 47 (34.3%) | 4 (13.8%) | 0.021 |
| Inability to complete diagnostic angiography (mid-angiography) | 54 (32.5%) | 46 (33.6%) | 8 (27.6%) | 0.347 |
| For PCI procedure (between diagnostic angiography and percutaneous coronary intervention) | 9 (5.4%) | 8 (5.8%) | 1 (3.4%) | 0.512 |
| After an initial attempt to cannulate the coronary artery with a guide catheter (during percutaneous coronary intervention) | 5 (3.0%) | 4 (2.9%) | 1 (3.4%) | 0.622 |
Univariate predictors of access site crossover included age >75 years (OR 1.63 [1.07–2.48], p=0.0228) and operator transradial experience ≤5 years (OR 2.80 [1.85–4.24], p<0.0001). While the rate of access site crossover in operators with >5 years of transradial experience (n=563) was 5.2%, the rate of access site crossover in operators with ≤5 years of transradial experience (n=1037) was 13.2%. The proportions of procedures that underwent access site crossover over time, stratified by operator transradial experience, are shown in Figure 1.
Figure 1.
A) Proportion of transradial (TRA) to transfemoral (TFA) approach crossover over quartiles of time (days) stratified by operator experience. B) Proportion of procedures performed by less experienced operators using initial TRA approach with reference to the proportion of access site crossover in this group over quartiles of time (days). C) Proportion of TRA to TFA crossover over quartiles of time (days) in the less experienced operator group stratified by operator (data are shown for top 3 operators that comprise 86% of the procedures). D) Timing of TRA to TFA crossover in the less experienced operator group stratified by operator (data are shown for top 3 operators that comprise 86% of the procedures).
After adjustment for operator experience, the association between age >75 years and access site crossover was strengthened (OR 1.90 [1.23–2.91], p=0.004). Similarly, after adjustment for age, the association between operator transradial experience and access site crossover strengthened (OR 2.98 [1.96–4.52], p<0.0001).
Discussion
This is one of the larger contemporary studies to examine access site crossover (from TRA to TFA) in an all comers population undergoing coronary angiography with possible PCI by operators with varied TRA experience in a U.S. center. In this study, the proportion of access site crossover appears to be largely driven by patient age and operator experience. Rate of access site crossover in those with less TRA experience decreases over time as operator utilization of TRA increases, suggesting that operator experience is a modifiable factor.
The 10.4% rate of access site crossover in this study compares to those reported by other centers, which ranges anywhere between 0.7% and 13.8% (9–11). One of the largest studies to date, the multicenter international Radial versus Femoral Access for Coronary Angiography and Intervention in Patients with Acute Coronary Syndromes (RIVAL) trial, reported a 7.0% TRA failure rate, while the multicenter international Radial Versus Femoral Randomized Investigation in ST-Elevation Acute Coronary Syndrome (RIFLE-STEACS) trial reported a 9.6% crossover rate in TRA procedures performed by high-volume operators (1,5). In the current study, the more experienced operators had a crossover rate of 5.2%. This is comparable to a recent meta-analysis by Bertrand et al that reported a mean access site crossover crossover rate of 4.5% in patients undergoing PCI but higher than the 3.8% crossover rate reported by Vink et al in a large observational study of patients from a high-volume center in the Netherlands presenting with ST-segment elevation myocardial infarction (12–13). Although Ball et al also noted a low 4% TRA-PCI failure rate, only non urgent, single vessel TRA-PCI procedures were selected for evaluation, whereas the current study included a more diverse population (14).
In the current study, the only patient characteristic found to correlate with access site crossover was age >75 years. This is consistent with a subgroup analysis from the prospective randomized Transradial Approach (Left vs Right) and Procedural Times During Percutaneous Coronary Procedures (TALENT) study, which demonstrated age >70 years as an independent predictor of subclavian tortuosity (15). A large retrospective analysis by Cha et al reported additional patient characteristics associated with severe right subclavian tortuosity, including female gender, short stature, presence of hypertension, and higher body mass index (16). Although the majority of cases in the current study utilized a right radial approach, more than one third of patients were female, and more than a quarter of patients were < 64 inches, TRA to TFA crossover rate was not associated with these other patient characteristics. Another large retrospective study by Dehghani et al reported only age >75 years, prior coronary artery bypass graft surgery, and short stature as independent predictors of TRA failure (17). Given the rate of patients with prior coronary artery bypass graft surgery was very low in the current study, it is likely that patient selection for TRA versus TFA access played a role in the current results. A multicenter prospective study of 1540 patients in the United Kingdom demonstrated anomalous radial artery anatomy to be associated with TRA failure, and age to be the only independent predictor of a radial artery anomaly (18).
Operator experience was the only procedural characteristic to influence rate of access site crossover. The TALENT study highlighted the potential benefit of a left radial artery approach with less experienced operators (15). Furthermore, subgroup analyses of the TALENT study demonstrated a higher prevalence of subclavian artery tortuosity with right versus left TRA, and age ≥70 years was an independent predictor of subclavian artery tortuosity. However, left radial artery access is not routinely performed due to operator physical discomfort when working from the traditional right side of the patient. In the current study, there was no systematic selection protocol for right versus left TRA, and the majority of patients underwent a right radial artery approach. Although multiple studies have shown that operator experience is associated with lower TRA crossover rate and procedural time, few have evaluated the change in crossover rate with time as operator experience increases (11,13,19–22). In the current study, more experienced operators had low and steady rates of crossover over time, while less experienced operators were associated with an overall decrease in rate of crossover over time. Interestingly, less experienced operators had a low crossover rate early in the observational period. This is likely due to patient selection given that these operators’ rate of initial TRA approach was also very low at the start of the study and increased over time.
There are several limitations with the present study, including those inherent to a retrospective single center analysis such as the possibility of unmeasured confounders. This analysis represents procedures performed at a high volume center with a combination of experienced and less experienced operators. Centers with lower volume or without experienced TRA operators to teach radial techniques may not necessarily observe the same data.
Acknowledgments
Funding Sources: Dr. Shah was partially funded by a NIH grant (UL1 TR000038). Part of the data analysis and statistical support was provided by New York University School of Medicine Cardiovascular Outcomes Group.
Footnotes
Disclosures
Dr. Coppola is a consultant for Terumo and speaker for Medtronic. The authors have no conflicts of interest in relation to this manuscript.
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