06 Apr 2021
Radial artery dilatation to improve access and lower complications during coronary angiography: the RADIAL trial
Selected in EuroIntervention by A. N. Calik
The RADIAL study sought to explore the impact of prolonged occlusion flow-mediated dilatation (PO-FMD) in improving radial artery cannulation success.
References
Authors
Jacques Doubell, Charles Kyriakakis, Hellmuth Weich, Philip Herbst, Alfonso Pecoraro, Jane Moses, Bradley Griffiths, H. W. Snyman, Lorrita Kabwe, Rudolf Du Toit, Lloyd Joubert, Karim Hassan, Anton Doubell
Reference
10.4244/EIJ-D-19-00207
Published
March 2021
Link
Read the abstractReviewer
My Comment
Why this study? – the rationale/objective
Radial artery cannulation has now become the choice of access for coronary angiography and percutaneous coronary interventions (PCI) due to its lower bleeding, vascular complication and mortality rates than femoral access.
Because of its relatively smaller diameter and predisposition to vasospasm, all efforts should be given to preclude complications such as radial artery spasm and occlusion by decreasing the number of puncture attempts.
Based on the fact that radial artery flow-mediated dilatation (FMD) can be achieved by blocking the brachial artery simply by inflation of a blood pressure cuff above the systolic pressure for a while, the RADIAL study sought to explore the impact of prolonged occlusion flow-mediated dilatation (PO-FMD) in improving radial artery cannulation success.
How was it executed? – the methodology
The RADIAL study included patients undergoing coronary angiography, except for primary PCI or rescue PCI, and excluded patients with a hemodynamic compromise that precludes brachial occlusion for flow mediation and ultrasound assessment, performed to all participants before angiography.
The study population randomly assigned into two groups: PO-FMD group (the blood pressure cuff had been inflated to 50 mmHg above the patient’s systolic blood pressure for 10 minutes and deflated just before the puncture) and sham PO-FMD group (the blood pressure cuff put over the right brachial artery but not inflated). Palpation-guided radial cannulation was defined as the default strategy for gaining access.
The primary objective of the study was to evaluate the impact of PO-FMD on the transradial cannulation failure rate. Also, the number of radial artery puncture attempts and their impact on the rates of radial artery spasm (RAS), radial artery pulsation loss (RAPL) and radial artery occlusion (RAO) were recorded.
What is the main result?
A total of 1,156 patients were recruited in the study. After exclusion, 560 PO-FMD and 570 sham PO-FMD patients were included in the analysis.
Flow chart illustrating the randomisation and exclusion of participants in the trial. Source: EuroIntervention
The PO-FMD approach significantly reduced unsuccessful transradial cannulation rates compared to sham procedure (2.7 % vs 5.8 %, respectively, p < 0.001). Also, puncture attempts were reduced from a median number of 2 to 1 and time to cannulation, with the aid of the PO-FMD strategy.
As regards complications, RAS and RAO rates did not reach statistical significance in both groups. However, the PO-FMD group suffered less from RAPL than the sham control group (1.4 % vs 3.8 %, respectively, p = 0.02).
Critical reading and the relevance for clinical practice:
The RADIAL trial showed that the non-invasive PO-FMD strategy, which is very simple and easy to implement into daily practice, decreased cannulation failure rates, reduced the number of radial artery puncture attempts and cannulation times.
It is also important to note that female patients included in the study had more radial artery puncture attempts and higher failed cannulation rates than male patients.
Besides its potential benefit for beginner operators, using the PO-FMD approach in women and patients with smaller radial artery diameter seems a reasonable strategy.
1 comment
Effect of PO-FMD on radial artery dimension lasts less than 5 minutes. Although PO-FMD may improve radial artery cannulation, catheterization procedure may be challenging after the first 5 minutes if the radial artery is prone to spasm.