Abstract
Background
Results from the Distal vs Conventional Radial Access (DISCO RADIAL) trial confirmed distal radial access (DRA) as a valid alternative to conventional transradial access, with equally low rates of radial artery occlusion (RAO), yet higher crossovers but shorter hemostasis.
Objectives
The purpose of the study was to investigate whether patient anthropometric measures influence the effect of randomized access on key secondary outcomes.
Methods
DISCO RADIAL was an international, multicenter, randomized controlled trial in which patients with indications for percutaneous coronary procedure using a 6-F Slender sheath were randomized to DRA (n = 650) or transradial access (n = 657) implementing best practices to reduce RAO. The primary endpoint of the trial was incidence of forearm RAO, which was extremely uncommon. Secondary endpoints, including sheath insertion time, radial artery spasm, crossover (failure to obtain access through assigned access site), hemostasis time, and access site complications, were the focus of the current analysis. Regression models (linear for continuous and logistic for binary outcomes) were used to determine whether anthropometric measures (weight, height, body mass index, and body surface area) influenced the effect of randomized access on outcomes.
Results
Across tertiles of weight, height, body mass index, and body surface area, both before and after adjustment for sex and age, the main effect of vascular access on radial artery spasm, crossover, hemostasis time, and access site complications remained, with no significant interaction effect.
Conclusions
The results of this exploratory analysis are consistent with the main findings of the trial and support the use of DRA in all patients, regardless of anthropometric measures.
Key words: distal radial access, transradial access, weight, height, body mass index, body surface area
Central Illustration
Transradial access (TRA) has received a Class I recommendation as the preferred approach for percutaneous coronary interventions in both European and American guidelines on myocardial revascularization1,2 due to its multiple advantages over femoral access, including reduced mortality across the whole spectrum of patients with coronary artery disease.3 In recent years, distal radial access (DRA) has emerged as a refinement of conventional TRA, driven by its potential to improve procedural ergonomics and supported by physiological principles that offer the prospect of maintaining radial artery patency and further reducing complications.4, 5, 6 Notably, DRA has also been associated with very short hemostasis times, which may have significant implications for increasing patient autonomy.7 The benefits of DRA were first evaluated in 2 single-center randomized controlled trials (RCTs), specifically comparing the incidence of radial artery occlusion (RAO) between DRA and conventional TRA and showing a higher rate of forearm radial artery patency with DRA.8,9
More recently, the DISCO RADIAL (Distal vs Conventional Radial Access) trial, the largest multicenter RCT comparing DRA to conventional TRA with protocol-driven systematic implementation of best practices to prevent RAO, reported exceptionally low rates of RAO in both groups, but as a consequence could not reach statistical significance to demonstrate superiority of DRA in reducing this adverse event, even though the RAO rate in DRA group was approximately one-third that of conventional TRA group.10
However, a subsequent meta-analysis of 14 RCTs comparing DRA with conventional TRA and including DISCO RADIAL revealed an impressive 64% relative risk reduction in RAO, thus confirming DRA as a valid alternative to conventional TRA.11 In addition, DRA showed a remarkable 49% relative risk reduction in significant upper extremity hematoma compared to conventional TRA, despite being associated with an approximately twofold increased risk of crossover to alternative vascular access.
While the extremely low and significantly reduced rate of RAO can be considered a well-established advantage of DRA over conventional TRA, other aspects of DRA warrant further investigation to better understand how to best address them.12 Indeed, if the future patency of the artery is not critical to the procedure being performed, other factors may influence the choice of vascular access and potentially deprive the patient of the benefits of DRA.
With this in mind, the large size of the DISCO RADIAL trial provides a unique opportunity to explore potential interactions between patient-related factors and key secondary endpoints of the trial, such as access site crossover, radial artery spasm (RAS), or hemostasis duration.
Recognizing the common practice of anticipating radial access-related outcomes based on body size, the current analysis was conducted to examine whether anthropometric measures influence the effect of randomized access site on relevant secondary outcome measures.
Methods
Study organization
The DISCO RADIAL (Distal vs Conventional Radial Access) trial (NCT04171570) design and results have been previously published.10,13 Briefly, DISCO RADIAL was an international, multicenter, prospective RCT aiming to assess the superiority of DRA compared with conventional TRA with systematic implementation of best practices to reduce RAO (Central Illustration).14
Central Illustration.
Impact of Anthropometric Measures on Distal vs Conventional Radial Access for Percutaneous Coronary Procedures
In the DISCO RADIAL international multicenter randomized controlled trial patients with indications for percutaneous coronary procedure using 6-F Glidesheath Slender (Terumo) introducer sheath were randomized to distal radial access or conventional transradial access with systematic implementation of best practices to reduce radial artery occlusion (indicated by ∗). Of the study population, 1,303 patients were eligible for this subanalysis. Patients were divided into tertiles of relevant anthropometric measures and regression analysis was performed to assess whether anthropometric measures impacted the effect of randomized access on key secondary outcomes of the trial. No interaction was found between the main effect of vascular access on access site-related complications and hemostasis time, and body weight, height, BMI, and BSA. Results are adjusted for sex and age. Treatment effects for hemostasis time (minutes) are difference in least squares mean Log(time + 1). Abbreviations as in Figure 3.
The study enrolled 1,307 patients with indications for percutaneous coronary procedure using a 6-F Glidesheath Slender (Terumo) introducer sheath between December 2019 and October 2021, during which time the variable impact of the COVID-19 pandemic affected the enrollment process across participating countries.15 Patients and operators selection criteria were previously reported and are detailed in Supplemental Table 1.
Among 1,307 patients forming the intention-to-treat population of the DISCO RADIAL trial, 4 (0.3%) patients were excluded from weight analyses and 6 (0.5%) were excluded from eight-related analyses due to missing values (Figure 1).
Figure 1.
Flow Chart of the Study
DRA = distal radial access; TRA = transradial access.
The primary endpoint of the DISCO RADIAL trial was the incidence of forearm RAO at discharge assessed by ultrasound. Selected secondary endpoints including RAS, crossover to another vascular access (either from the contralateral arm, from another artery, or the other treatment group), access site complications, sheath insertion time, and hemostasis time are the focus of the current investigator-driven analysis. Endpoint definitions have been previously fully reported and are detailed in Supplemental Table 2.
The trial was sponsored by Terumo Europe.
Study procedures
The decision for right or left access, the utilization of ultrasound guidance, and the puncture technique were at the discretion of the operator. In case of DRA, careful manipulation of the needle was always recommended to prevent painful contact with the periosteum of the scaphoid or trapezium bones.12
Following the insertion of the 6-F Glidesheath Slender sheath spasmolytic drugs and unfractionated heparin were administered according to best practices.14
In case of unsuccess of the randomized access (DRA or conventional TRA) due to puncture failure, inability to advance a wire, refractory spasm, disproportionate pain, vascular damage, or marked vascular tortuosity, all subsequent efforts to obtain vascular access at an alternate site within the same limb or another limb were considered as crossover.
Hemostasis was achieved with an air-filled closure device according to the patent hemostasis protocol outlined in the PROPHET (Prevention of Radial Artery Occlusion Patent Hemostasis Evaluation Trial study16 after conventional TRA and per hospital practice after DRA.
Anthropometric measures
Weight and height were assessed at baseline in kilograms and centimeters, respectively. Body mass index (BMI) was calculated by the formula developed by Adolphe Quetelet: weight in kilograms/(height in meters),2 and body surface area (BSA) calculated according to Mosteller formula: [(weight in kilograms)·(height in centimeters)/3600]1/2.17
To facilitate trend analysis and comparisons between different categories, patients were divided into 3 groups (low, medium, high) based on each variable tertiles, as detailed in Figure 2 and Central Illustration.
Figure 2.
Patients Study Groups
Patients were divided into 3 groups based on tertiles of body weight, height, body mass index (BMI), and body surface area (BSA).
Statistical analysis
For the present analyses, only patients with complete baseline measurements of weight and height were included.
Continuous variables were analyzed using F-tests. A Kruskal-Wallis (nonparametric) test was employed for continuous variables with non-normal distributions. Categorical variables were compared using the Pearson chi-square test or Fisher’s exact test in the case of small cell counts. Continuous variables are presented as mean ± SD or median (IQR), as appropriate, whereas proportions are presented as counts (percentages).
Logistic regression was used to determine whether anthropometric measures (body weight, height, BMI, and BSA) impacted the effect of randomized access on binary outcomes. For each outcome, 2 models were built for each anthropometric measure: an unadjusted model, including the randomization group (DRA or conventional TRA), the single anthropometric measure of interest (weight, height, BMI, or BSA), and their interaction, and an adjusted model adding age and sex. Linear regression was likewise implemented for the continuous outcome variables (sheath insertion time and hemostasis time) after using a log transformation to achieve linearity. A value of 1 was added to the time measures before transformation to avoid logging zero. The Wald test was used to evaluate the statistical significance of these interaction terms.
A 2-tailed P value <0.05 was required for nominal statistical significance. Statistical tests were performed using SAS version 9.4 (SAS Institute).
Results
Baseline characteristics of the study population according to the randomized access in each tertile of body weight, height, BMI, and BSA are shown in Supplemental Tables 3-6.
Similarly, procedural characteristics according to the randomized access in each tertile of anthropometric measures are shown in Supplemental Tables 7 to 10.
Effect of the randomized access site in the total population
The overall unadjusted and adjusted associations between the randomized access site and RAS, crossover, access site complications, sheath insertion time, and hemostasis time are shown in Table 1. A higher likelihood of RAS (OR: 2.02; 95% CI: 1.13-3.61; P = 0.017) and crossover (odds ratio: 2.20; 95% CI: 1.32-3.66; P = 0.002) was observed with DRA, with no remarkable difference after adjustment for age and sex (Figure 3, Figure 4). A significantly shorter sheath insertion time (difference in least square mean[log time +1]: −0.114 minutes; 95% CI: −0.178 to −0.049 minutes; P < 0.001) and a significantly longer hemostasis time (difference in least square mean[log time +1]: 0.234 minutes; 95% CI: 0.152-0.316 minutes; P < 0.001] occurred with conventional TRA, without a substantial difference after adjusting for age and sex (Figure 5, Central Illustration).
Table 1.
Overall Effects of Randomization to DRA vs Conventional TRA
| Endpoint | Unadjusted OR (95% CI) | P Value | Adjusted OR (95% CI) | P Value |
|---|---|---|---|---|
| Radial arterial spasm | 2.02 (1.13-3.61) | 0.017 | 2.03 (1.14-3.62) | 0.017 |
| Vascular access crossover | 2.20 (1.32-3.66) | 0.002 | 2.28 (1.37-3.81) | 0.002 |
| Access site complications | 1.17 (0.76-1.79) | 0.479 | 1.21 (0.78-1.86) | 0.394 |
| Unadjusted LS Means Difference (95% CI) | Adjusted LS Means Difference (95% CI) | |||
| Log(sheath insertion time + 1) | 0.234 (0.152-0.316) | <0.001 | 0.233 (0.152-0.315) | <0.001 |
| Log(hemostasis time + 1) | −0.114 (−0.178 to −0.049) | <0.001 | −0.112 (−0.176 to −0.048) | <0.001 |
LS = least square.
Figure 3.
Effects of Randomization to Distal Radial Access vs Conventional Transradial Access on Radial Artery Spasm Across Tertiles of Anthropometric Measures
No interaction was found between the main effect of vascular access on radial artery spasm and body weight, height, BMI, and BSA. Results are adjusted for sex and age. BMI = body mass index; BSA = body surface area; DRA = distal radial access; TRA = transradial access.
Figure 4.
Effects of Randomization to Distal Radial Access vs Conventional Transradial Access on Access Site Crossover Across Tertiles of Anthropometric Measures
No interaction was found between the main effect of vascular access on access site crossover and body weight, height, BMI, and BSA. Results are adjusted for sex and age. Abbreviations as in Figure 3.
Figure 5.
Effects of Randomization to Distal Radial Access vs Conventional Transradial Access on Sheath Insertion Time Across Tertiles of Anthropometric Measures
No interaction was found between the main effect of vascular access on sheath insertion time and body weight, height, BMI, and BSA. Results are adjusted for sex and age. Treatment effects for sheath insertion time (minutes) are difference in least squares mean Log(time + 1). Abbreviations as in Figure 3.
Effect of the randomized access site according to anthropometric measures
The unadjusted and adjusted associations between the randomized access site and the study endpoints according to each tertile of body weight, height, BMI, and BSA are shown in Table 2, Table 3, Table 4, Table 5, Table 6. The findings are largely similar to those in the total study population and do not show substantial differences after adjustment for age and sex.
Table 2.
Effects of Randomization to DRA vs Conventional TRA on Radial Artery Spasm Across Tertiles of Anthropometric Measures
| Unadjusted OR (95% CI) |
P Value for Interaction |
Adjusted OR (95% CI) |
P Value for Interaction |
|
|---|---|---|---|---|
| Body weight | ||||
| 1st tertile DRA vs conventional TRA (n = 456) | 1.99 (0.88-4.53) | 0.753 | 1.97 (0.87-4.49) | 0.781 |
| 2nd tertile DRA vs conventional TRA (n = 418) | 2.66 (0.83-8.48) | 2.59 (0.81-8.27) | ||
| 3rd tertile DRA vs conventional TRA (n = 429) | 1.40 (0.42-4.65) | 1.42 (0.43-4.73) | ||
| Body height | ||||
| 1st tertile DRA vs conventional TRA (n = 443) | 1.67 (0.67-4.17) | 0.368 | 1.65 (0.66-4.12) | 0.370 |
| 2nd tertile DRA vs conventional TRA (n = 447) | 3.45 (1.25-9.52) | 3.45 (1.25-9.53) | ||
| 3rd tertile DRA vs conventional TRA (n = 411) | 1.18 (0.35-3.92) | 1.19 (0.36-3.97) | ||
| BMI | ||||
| 1st tertile DRA vs conventional TRA (n = 434) | 1.46 (0.62-3.45) | 0.696 | 1.47 (0.62-3.47) | 0.702 |
| 2nd tertile DRA vs conventional TRA (n = 454) | 2.40 (0.91-6.30) | 2.39 (0.91-6.28) | ||
| 3rd tertile DRA vs conventional TRA (n = 413) | 2.49 (0.61-10.09) | 2.49 (0.61-10.12) | ||
| BSA | ||||
| 1st tertile DRA vs conventional TRA (n = 436) | 1.79 (0.80-4.01) | 0.596 | 1.77 (0.79-3.97) | 0.626 |
| 2nd tertile DRA vs conventional TRA (n = 433) | 3.55 (0.98-12.89) | 3.44 (0.95-12.53) | ||
| 3rd tertile DRA vs conventional TRA (n = 432) | 1.53 (0.48-4.88) | 1.56 (0.49-4.99) |
DRA = distal radial access; TRA = transradial access.
Table 3.
Effects of Randomization to DRA vs Conventional TRA on Vascular Access Crossover Across Tertiles of Anthropometric Measures
| Unadjusted OR (95% CI) |
P Value for Interaction |
Adjusted OR (95% CI) |
P Value for Interaction |
|
|---|---|---|---|---|
| Body weight | ||||
| 1st tertile DRA vs conventional TRA (n = 456) | 2.60 (1.18-5.76) | 0.704 | 2.72 (1.22-6.04) | 0.645 |
| 2nd tertile DRA vs conventional TRA (n = 418) | 2.66 (0.83-8.48) | 2.91 (0.91-9.32) | ||
| 3rd tertile DRA vs conventional TRA (n = 429) | 1.66 (0.72-3.84) | 1.67 (0.72-3.87) | ||
| Body height | ||||
| 1st tertile DRA vs conventional TRA (n = 443) | 2.95 (1.38-6.31) | 0.080 | 3.07 (1.43-6.58) | 0.072 |
| 2nd tertile DRA vs conventional TRA (n = 447) | 3.79 (1.24-11.59) | 3.81 (1.24-11.67) | ||
| 3rd tertile DRA vs conventional TRA (n = 411) | 0.86 (0.33-2.28) | 0.86 (0.32-2.26) | ||
| BMI | ||||
| 1st tertile DRA vs conventional TRA (n = 434) | 2.48 (1.02-6.08) | 0.840 | 2.56 (1.04-6.30) | 0.794 |
| 2nd tertile DRA vs conventional TRA (n = 454) | 1.76 (0.69-4.49) | 1.77 (0.69-4.54) | ||
| 3rd tertile DRA vs conventional TRA (n = 413) | 2.44 (1.06-5.60) | 2.65 (1.14-6.14) | ||
| BSA | ||||
| 1st tertile DRA vs conventional TRA (n = 436) | 2.50 (1.16-5.39) | 0.392 | 2.62 (1.21-5.67) | 0.338 |
| 2nd tertile DRA vs conventional TRA (n = 433) | 3.89 (1.08-13.97) | 4.13 (1.14-14.89) | ||
| 3rd tertile DRA vs conventional TRA (n = 432) | 1.43 (0.61-3.33) | 1.41 (0.60-3.29) |
Abbreviations as in Table 2.
Table 4.
Effects of Randomization to DRA vs Conventional TRA on Access Site Complications Across Tertiles of Anthropometric Measures
| Unadjusted OR (95% CI) |
P Value for Interaction |
Adjusted OR (95% CI) |
P Value for Interaction |
|
|---|---|---|---|---|
| Body weight | ||||
| 1st tertile DRA vs conventional TRA (n = 456) | 1.05 (0.57-1.96) | 0.861 | 1.09 (0.58-2.04) | 0.898 |
| 2nd tertile DRA vs conventional TRA (n = 418) | 1.11 (0.49-2.54) | 1.20 (0.52-2.77) | ||
| 3rd tertile DRA vs conventional TRA (n = 429) | 1.41 (0.60-3.34) | 1.40 (0.59-3.33) | ||
| Body height | ||||
| 1st tertile DRA vs conventional TRA (n = 443) | 0.94 (0.50-1.77) | 0.203 | 0.98 (0.52-1.85) | 0.233 |
| 2nd tertile DRA vs conventional TRA (n = 447) | 0.96 (0.43-2.12) | 0.96 (0.43-2.13) | ||
| 3rd tertile DRA vs conventional TRA (n = 411) | 2.55 (0.97-6.71) | 2.51 (0.95-6.61) | ||
| BMI | ||||
| 1st tertile DRA vs conventional TRA (n = 434) | 1.65 (0.83-3.28) | 0.352 | 1.70 (0.85-3.40) | 0.340 |
| 2nd tertile DRA vs conventional TRA (n = 454) | 0.80 (0.39-1.65) | 0.80 (0.39-1.66) | ||
| 3rd tertile DRA vs conventional TRA (n = 413) | 1.00 (0.40-2.46) | 1.08 (0.43-2.67) | ||
| BSA | ||||
| 1st tertile DRA vs conventional TRA (n = 436) | 0.92 (0.49-1.72) | 0.589 | 0.95 (0.51-1.79) | 0.601 |
| 2nd tertile DRA vs conventional TRA (n = 433) | 1.48 (0.63-3.50) | 1.58 (0.67-3.74) | ||
| 3rd tertile DRA vs conventional TRA (n = 432) | 1.43 (0.61-3.33) | 1.39 (0.60-3.26) |
Abbreviations as in Table 2.
Table 5.
Effects of Randomization to DRA vs Conventional TRA on Sheath Insertion Time Across Tertiles of Anthropometric Measures
| Unadjusted LS Means Difference (95% CI) |
P Value for Interaction |
Adjusted LS Means Difference (95% CI) |
P Value for Interaction |
|
|---|---|---|---|---|
| Body weight | ||||
| 1st tertile DRA vs conventional TRA (n = 456) | 0.250 min (0.112-0.389 min) | 0.651 | 0.253 min (0.115-0.391 min) | 0.781 |
| 2nd tertile DRA vs conventional TRA (n = 418) | 0.280 min (0.135-0.425 min) | 0.286 min (0.141-0.431 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 429) | 0.186 min (0.042-0.329 min) | 0.178 min (0.035-0.321 min) | ||
| Body height | ||||
| 1st tertile DRA vs conventional TRA (n = 443) | 0.273 min (0.132-0.413 min) | 0.087 | 0.277 min (0.136-0.417 min) | 0.067 |
| 2nd tertile DRA vs conventional TRA (n = 447) | 0.327 min (0.186-0.467 min) | 0.328 min (0.188-0.467 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 411) | 0.106 min (−0.039 to 0.252 min) | 0.099 min (−0.047 to 0.244 min) | ||
| BMI | ||||
| 1st tertile DRA vs conventional TRA (n = 434) | 0.223 min (0.081-0.365 min) | 0.971 | 0.221 min (0.079-0.363 min) | 0.963 |
| 2nd tertile DRA vs conventional TRA (n = 454) | 0.243 min (0.103-0.382 min) | 0.246 min (0.107-0.384 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 413) | 0.246 min (0.099-0.393 min) | 0.246 min (0.100-0.393 min) | ||
| BSA | ||||
| 1st tertile DRA vs conventional TRA (n = 436) | 0.297 min (0.155-0.439 min) | 0.515 | 0.296 min (0.155-0.438 min) | 0.465 |
| 2nd tertile DRA vs conventional TRA (n = 433) | 0.238 min (0.095-0.380 min) | 0.246 min (0.104-0.388 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 432) | 0.179 min (0.037-0.322 min) | 0.171 min (0.028-0.313 min) |
Values are Log(sheath insertion time + 1).
LS = least squares; other abbreviations as in Table 2.
Table 6.
Effects of Randomization to DRA vs Conventional TRA on Hemostasis Time Across Tertiles of Anthropometric Measures
| Unadjusted LS Means Difference (95% CI) |
P Value for Interaction |
Adjusted LS Means Difference (95% CI) |
P Value for Interaction |
|
|---|---|---|---|---|
| Body weight | ||||
| 1st tertile DRA vs conventional TRA (n = 456) | −0.123 min (−0.231 to −0.015 min) | 0.863 | −0.120 min (−0.228 to −0.013 min) | 0.784 |
| 2nd tertile DRA vs conventional TRA (n = 418) | −0.087 min (−0.201 to 0.026 min) | −0.080 min (−0.194 to 0.033 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 429) | −0.128 min (−0.241 to −0.015 min) | −0.135 min (−0.247 to −0.023 min) | ||
| Body height | ||||
| 1st tertile DRA vs conventional TRA (n = 443) | −0.083 min (−0.196 to 0.029 min) | 0.846 | −0.078 min (−0.190 to 0.034 min) | 0.787 |
| 2nd tertile DRA vs conventional TRA (n = 447) | −0.123 min (−0.233 to −0.013 min) | −0.122 min (−0.232 to −0.013 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 411) | −0.125 min (−0.238 to −0.012 min) | −0.130 min (−0.243 to −0.018 min) | ||
| BMI | ||||
| 1st tertile DRA vs conventional TRA (n = 434) | −0.131 min (−0.242 to −0.021 min) | 0.915 | −0.133 min (−0.242 to −0.023 min) | 0.895 |
| 2nd tertile DRA vs conventional TRA (n = 454) | −0.099 min (−0.207 to 0.009 min) | −0.096 min (−0.203 to 0.012 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 413) | −0.121 min (−0.239 to −0.003 min) | −0.117 min (−0.235-0.001 min) | ||
| BSA | ||||
| 1st tertile DRA vs conventional TRA (n = 436) | −0.113 min (−0.225 to −0.001 min) | 0.894 | −0.112 min (−0.223 to −0.001 min) | 0.962 |
| 2nd tertile DRA vs conventional TRA (n = 433) | −0.129 min (−0.241 to −0.018 min) | −0.121 min (−0.233 to −0.010 min) | ||
| 3rd tertile DRA vs conventional TRA (n = 432) | −0.091 min (−0.203 to 0.021 min) | −0.099 min (−0.211 to 0.012 min) |
Values are Log(hemostasis time + 1).
Abbreviations as in Table 5.
For RAS, the effect of randomization to DRA or conventional TRA was largely consistent across tertiles of body weight, height, BMI and BSA (Table 2). With the exception of the second tertile of height, no significant differences were found between DRA and conventional TRA across the tertiles. Also, no significant interaction effect was noted between the randomized access and any anthropometric measure (Figure 3).
As shown in Table 3, crossover to another vascular access was significantly more likely with DRA than with conventional TRA in several tertiles of all anthropometric measures. Yet, no significant interaction effect was detected, although a trend was observed for height (Figure 4).
The incidence of access site complications did not appear to differ significantly between DRA and conventional TRA across tertiles of body weight, height, BMI, and BSA, with no significant interaction effect for any anthropometric measure (Table 4 and Central Illustration).
Sheath insertion time was found to be significantly shorter with conventional TRA than with DRA with a high consistency across the tertiles of anthropometric measures (Table 5). Once more, no significant interaction effect was observed, although there was a trend for height with no significant difference between groups in the third tertile (Figure 5).
As shown in Table 6, hemostasis time appeared to be evidently shorter with DRA compared to conventional TRA, although the difference was not statistically significant for each tertile of anthropometric measures. No significant interaction effect was found between randomized access and any anthropometric measure (Central Illustration).
Discussion
The DISCO RADIAL trial was the first international multicenter RCT comparing DRA with conventional TRA in patients undergoing percutaneous coronary procedures.10 This secondary analysis of the DISCO RADIAL trial uniquely evaluates the effect of randomization to DRA or conventional TRA on selected endpoints according to multiple different anthropometric measures. Specifically, we showed that the main effect of vascular access on: 1) radial artery spasm; 2) sheath insertion time; 3) crossover; 4) hemostasis time; and 5) access site complications remained essentially consistent across tertiles of: 1) body weight; 2) height; 3) body mass index; and 4) body surface area, both before and after adjustment for sex and age, with no statistically significant interaction effects detected.
Beyond the primary finding of a very low rate of ultrasound-assessed forearm RAO following both DRA and conventional TRA, the secondary endpoints of the DISCO RADIAL trial provided a comprehensive and detailed account of the entire journey of a patient undergoing a percutaneous coronary procedure.10 Those results indicate that while the adoption of DRA did not affect the performance of the coronary procedure, it did introduce an apparent trade-off between the ease of the vessel puncture and the safety of the hemostasis process. Indeed, we specifically evaluated endpoints belonging to the vascular access phase and to the hemostasis and post-procedural phase to better understand whether selected patient profiles may be more susceptible to the higher complexity of distal radial artery puncture or, conversely, whether some may benefit more from DRA. This could conceivably help to optimally target strategies, such as ultrasound guidance, to warrant DRA in both the most challenging and the most beneficial cases.
Moreover, the provision of scientific data in this area is of paramount importance to improve and substantiate clinical practice and teaching within the discipline, which, in the absence of evidence-based data, is typically founded on personal preference or derived from anecdotal cases. Actually, body size, even more than sex and age, is arguably the most obvious and memorable patient characteristic to an interventional cardiologist,18 thus providing the primary focus of our investigation.
Previous research with conventional TRA has largely been directed at developing predictive scores for access failure and crossover to help operators anticipate and potentially manage difficulties in performing transradial procedures. Two scores developed on large populations have initially identified age >75 years, prior coronary artery bypass graft surgery, short stature, female sex, and cardiogenic shock as independent predictors of radial procedure failure.19,20 More recently, an eight-item risk score was derived from the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) trial, which included 4,197 patients with acute coronary syndrome who underwent invasive treatment via randomized radial access.21 Assessment of the MATRIX score is slightly more complex as it includes age, height, smoking status, history of renal failure, prior coronary artery bypass graft surgery, Killip class, ST-elevation myocardial infarction at presentation, and radial expertise.
Age, sex, and height are the biometric variables included in these scores, but not consistently. Actually, short stature, present in 2 of the previously reported scores, is associated with upper extremity vascular tortuosity, which may be a cause of radial procedure failure.22 A similar association has also been found for lower BSA and older age.23 Small radial artery diameter is another potential reason for access site crossover and has been consistently reported with female sex23, 24, 25 and with smaller anthropometric measures in some studies23,24 but not in all.26 More recently, a nomogram incorporating psychological factors has been developed to predict RAS in conventional TRA. Of the 6 items included in the model, only BMI was a biometric variable, and it showed a negative predictive association with RAS.27 While predictive data regarding access site adverse events following conventional TRA are scarce, an analysis of the EASY (EArly discharge after transradial Stenting of coronarY arteries) trial, which included 1,348 patients with acute coronary syndrome undergoing transradial percutaneous coronary intervention, revealed that no biometric measure was identified as a predictor of bleeding.28
The applicability of this set of information to DRA is, however, uncertain. In contrast to RCTs comparing conventional TRA with femoral access, which required large numbers of patients to detect a difference in low-rate events such as mortality, similar population sizes are unlikely to be available for DRA. This is due to the different objectives of DRA trials, which target vascular access-related variables occurring more commonly.
While the specific causes of primary access failure were not documented in the DISCO RADIAL trial, it is noteworthy that approximately two-thirds of crossovers in the DRA group were to ipsilateral conventional TRA. This observation suggests that vessel tortuosity is unlikely to be a major contributor to these crossovers, as it would not be different when targeting the same artery at a different puncture site. Instead, the narrower diameter of the radial artery in its distal portion,29, 30, 31 combined with its curvilinear and less predictable anatomy4 may be more relevant to DRA crossovers. These factors can lead to repeated punctures, which also contribute to a higher incidence of radial artery spasm (RAS) and overall longer sheath insertion times. Notably, despite the increased technical demands and potential stress associated with DRA punctures, there was no significant difference in bleeding or vascular complications between the 2 study groups.
In a large retrospective single-center registry of 3,610 Japanese patients undergoing a DRA percutaneous coronary procedure, body weight below the median (62 kg) was the only independent biometric predictor of both DRA failure and access site complications.32 It is noteworthy that the median body weight in this study was well below the first tertile in our population, which may explain the apparent contrast with the lack of interaction between weight-related measures and the randomization to DRA or conventional TRA in our analysis. In the same Japanese study, ultrasound-guided puncture was the only technique to show a reduction in both DRA failure and access site complications, consistent with previous preliminary findings.33
Our granular analysis of the interaction between 4 different anthropometric measures and randomized access did not identify any subgroup requiring special focus to overcome the shortcomings or ensure the benefits of DRA. Consistently, a post-hoc analysis of 2 RCTs showed that a nonpalpable distal radial artery was associated with comparable DRA success rates of around 80%.34
Overall, the available evidence on ultrasound-guided DRA may be seen as an inspiring stride toward establishing a systematic approach that maximizes opportunity for every patient to benefit from DRA, ultimately raising the standards of interventional practice.
Study limitations
As with all post-hoc analyses, our results are exploratory in nature and apply primarily to the setting of the original DISCO RADIAL trial. However, the potential for major bias is unlikely because all endpoints were precisely prespecified. According to the study protocol, participating operators were required to have a high level of expertise in both conventional TRA and DRA, and best practices to reduce RAO had to be thoroughly implemented in all cases. Whether this specific circumstance may have affected the primary results or our secondary analysis cannot be determined.
Conclusions
In patients undergoing a percutaneous coronary procedure in the largest multicenter RCT comparing DRA with conventional TRA, no interaction was found between the main effect of vascular access on all endpoints assessed, including RAS, crossover, access site complications, sheath insertion time, and hemostasis time, and 4 body measures, including weight, height, BMI, and BSA, both before and after adjustment for sex and age.
The results of this exploratory analysis are consistent with the primary results of the trial and support the use of DRA in all patients regardless of anthropometric measures.
Perspectives.
COMPETENCY IN MEDICAL KNOWLEDGE: In this secondary analysis of the DISCO RADIAL randomized trial, regression analyses showed that the main effect of vascular access on radial artery spasm, crossover, sheath insertion time, hemostasis time, and access site complications persisted across tertiles of body weight, height, body mass index, and body surface area, both before and after adjustment for sex and age, with no significant interaction effect.
TRANSLATIONAL OUTLOOK: While further studies are needed to confirm the results in a real-world setting, these robust findings strongly support distal radial access in all patients, regardless of anthropometric measures.
Funding support and author disclosures
The trial was sponsored and funded by Terumo Europe. Drs Sgueglia and Leibundgut have received consulting and lecture fees from Terumo and Cordis outside of the submitted work. Drs Aminian and Ratib have received consulting and lecture fees from Terumo. Dr Iglesias has received an unrestricted research grant to the institution from Terumo, outside of the submitted work; is a consultant for and has received personal fees from Terumo, outside of the submitted work; has received research grants to the institution from Abbott Vascular, AstraZeneca, Biosensors, Biotronik, Concept Medical, and Philips Volcano; and has received personal fees from AstraZeneca, Biotronik, Bristol Myers Squibb/Pfizer, Cardinal Health, Medtronic, Novartis, and Philips Volcano, outside the submitted work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
Appendix
For supplemental tables, please see the online version of this paper.
Supplementary Data
References
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