Ultrasound guided trans-radial access in the cardiac catheterisation laboratory: a systematic review and meta-analysis

Background Although ultrasound (US) guidance for vascular access is now widely considered standard of care (1,2), its use for trans-radial access (TRA) in the cardiac catheterization laboratory is uncommon. There is a perception that US guidance offers no clinically relevant benefit over traditional palpation guided TRA, and this notion has been amplified by the inconsistent findings of individual studies. Purpose To evaluate the utility of US guidance for TRA when performed specifically for cardiac catheterisation. Methods A systematic review of MEDLINE, EMBASE and the Cochrane Library identified studies comparing US to palpation guided TRA for cardiac catheterization. Event rates and calculated risk ratios (RR) were pooled for meta-analysis. Access failure was the primary outcome, defined as an inability to insert a sheath into the radial artery with the initial access strategy (US or palpation guided). Random effects modelling was used for analysis. Results Of the 977 studies screened, 5 were included with a total of 1,918 patients (961 US-guided and 964 palpation-guided, Table 1). The majority of procedures were elective. US guidance significantly lowered the risk of access failure (risk ratio [RR] 0.45, 95% confidence interval [CI] 0.21 – 0.97), with moderate heterogeneity (I^2 = 51.2%) (Figure 1). There was a strong trend to improved first pass success with US (RR 1.29, 95% CI 1.00 – 1.66, I^2 = 83.8%), though no differences were found in rates of difficult access (RR 0.29, 95% CI 0.07 - 1.18, I^2 = 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 radial artery spasm (RR 0.92, 95% CI 0.52 – 1.62, I^2 = 34.8%) and bleeding (RR 0.92, 95% CI 0.40 – 2.11, I^2 = 0.0%). No studies evaluated patient-reported outcome measures. Conclusions US guidance improves TRA success in the cardiac catheterisation laboratory. Further investigation is necessary to determine whether routine, selective, or salvage use of US confers the most radial artery protection, patient satisfaction, and overall clinical benefit. Future studies should have standardised outcome measures including femoral crossover rates and patient reported outcome measures