Although ultrasound (US) guidance for vascular access has been widely adopted, its use for transradial access (TRA) in the cardiac catheterisation laboratory is rare. There is a perception that US guidance does not offer a clinically relevant benefit over traditional palpation-guided TRA, amplified by inconsistent findings of individual studies.

A systematic review of MEDLINE, EMBASE and the Cochrane Library identified studies comparing US to palpation-guided TRA for cardiac catheterisation. Studies evaluating radial artery (RA) cannulation for any other reason were excluded. Event rates and risk ratios (RRs) were pooled for meta-analysis. Access failure was the primary outcome. A random-effects model was used for analysis.

Of the 977 records screened, four studies with a total of 1,718 patients (861 US-guided and 864 palpation-guided procedures) were included in the meta-analysis. Most procedures were elective. The pooled analysis showed US guidance significantly lowered the risk of access failure (RR 0.45; 95% confidence interval [CI] 0.21–0.97; p=0.04). Heterogeneity was moderate (I²=51.2%; p=0.105). There was a strong trend to improved first-pass success with US (RR 1.29; 95% CI 1.00–1.66; p=0.05; I²=83.8%), although no differences were found in rates of difficult access (RR 0.29; 95% CI 0.07–1.18; p=0.09; I²=88.3%). Salvage US guidance was successful in 30/41 (73.2%) patients following failed palpation-guided TRA. No differences were found in already low complication rates including RA spasm (RR 1.18; 95% CI 0.70–1.99; p=0.53; I²=0.0%) and bleeding (RR 1.32; 95% CI 0.46–3.80; p=0.60; I²=0.0%).

US guidance was found to improve TRA success in the cardiac catheterisation laboratory. Further investigation is necessary to determine whether routine, selective, or salvage use of US confers the most RA protection, patient satisfaction, and overall clinical benefit. (PROSPERO registration: CRD42022332238).