The radiation dose absorbed by operators was significantly lower in physicians who performed radial coronary interventions via the left artery compared with physicians who used the right artery. That was the finding of a randomized trial published online Jan. 23 in the Heart.
In 2012, Marcello Dominici, MD, of Santa Maria University Hospital in Terni, Italy, and colleagues had demonstrated that the left radial approach was safe and feasible in a study that compared left radial access to right radial access (J Interv Cardiol 2012;25:203-209). The researchers also reported a reduction in fluoroscopy time, which they suggested may be due to favorable vascular anatomy.
Yet left radial access (LRA) “is far from being widely accepted as a valid alternative to the classic RRA [right radial access] or femoral approach,” they wrote in the present study. “LRA is indeed commonly regarded as an uncomfortable access that could be associated with high radiation exposure for operators.”
To test whether those concerns were grounded in fact, Dominici and colleagues designed a randomized, prospective single-center study to compare radiation exposure to operators during coronary artery catheterization. They enrolled 413 patients, randomized to RRA procedures (209 patients) or LRA procedures (204 patients). The primary outcome was radiation dose absorbed by operators and the secondary outcomes were fluoroscopy time, dose-area product (DAP) and contrast delivered.
They included only diagnostic procedures in native coronary arteries; patients who had a previous coronary artery bypass, hemodynamic instability, STEMI or ischemic Allen’s test and patients under treatment for arteriovenous fistula were excluded.
Operators wore a dosimeter on the left side of their necks. They all received radiation protection that included standard leaded aprons, thyroid collars, leaded glasses and overhanging shields. Five operators participated in the study: two senior operators with experience in both RRA and LRA and three junior operators who were experienced in femoral access but had performed less than 100 radial access cases using RRA or LRA.
Radiation dose was significantly lower in operators who treated patients in the LRA group, at 33 μSv vs. 44 μSv for those using RRA. There was no significant difference is fluoroscopy time, DAP or contrast medium delivered, although Dominici et al reported a trend toward lower levels of fluoroscopy time and DAP with LRA.
The results held up in an analysis of experienced and less experienced operators. Radiation exposure in senior operators using RRA was 19 μSv vs. 9 μSv using LRA. In junior operators, it was 59 μSv using RRA and 48 μSv using LRA.
Dominici et al proposed that LRA offers many advantages over RRA. “[T]he vascular anatomy associated with RRA has some peculiarities that could impair the procedural success, namely the presence of the right subclavian artery-common brachiocephalic trunk (CBT) and the CBT-aorta bifurcations that could account for tortuosity and calcifications. … Furthermore the right side location in RRA requires a catheter movement technique that is different from the one used with femoral access and therefore requires a specific and longer learning curve.”
”[D]uring complex procedures the operators are usually forced to get closer to the patient with a consequent higher dose of radiation absorbed; this mechanism could be also implied in the higher radiation dose observed during RRA in particular, in inexperienced operators,” they wrote.
The left subclavian artery, on the other hand, stems from the aortic arch for less catheter bending that induces a catheter shape akin to femoral procedures.
While LRA is considered high risk for radiation because the operator leans over the patient to reach the left side, the protocol used in the study may minimize leaning. It called for the operator to be positioned at the patient’s right side while puncturing the artery. The operator then raised the patient’s left arm in a dedicated support; rotated it to become supine; introduced the vascular sheath; and rotated and adducted the forearm.
The authors wrote that they used preshaped catheters for femoral approaches and that the use of dedicated catheters for radial approaches might change the results. They recommended further comparative studies to measure radiation dose at other parts of the operator’s body.