**8. Right vs. left radial access in acute myocardial infarction**

Data from published studies addressing the best transradial approach (TRA) (right vs. left) in the setting of primary PCI are scarce, while data in the setting of elective PCI are controversial. Although the right radial artery (RRA) approach is usually the first point of access, tortuosity within the brachial and subclavian arteries may result in more radiation exposure, lengthy procedure, or even procedural failure [34, 36, 37]. Alternatively, the left radial artery (LRA) approach, although unflavored and less extensively studied, may offer an advantage from the point‐of‐view of vascular anatomy [29, 33].

Since delay in the reperfusion, time is considered the main cause of mortality in STEMI patients [38, 39], it is essential to decrease the reperfusion time when undergoing primary PCI. As the choice of transradial access site over the femoral approach is preferred in patients with STEMI because of less bleeding complications, it remains undetermined whether RRA or LRA pro‐ vides a shorter procedural time in STEMI patients undergoing primary PCI. Up to date, only a few researches have compared the access side (right vs. left) during primary PCI [40–42].

We did a retrospective study on 400 consecutive patients presenting to our hospital with STEMI. Primary PCIs were performed for 202 patients using the right radial approach and 198 using the left radial approach. Results show that there was no significant difference in demo‐ graphics and clinical characteristics for patients included in both groups with mean age 57 ± 12.8 years, with male predominance (77.2%). There was no significant difference between the right radial and left radial regarding success rate (97.5 for RRA vs. 98.4% for LRA; *P* = 0.77), contrast amount used (151.2 ± 12.4 ml for the RRA vs. 150.8 ± 19.6 ml for the LRA; *P* = 0.41), fluoroscopy time (FT) (13.2 ± 4.3 min for the RRA vs. 12.8 ± 3.5 min for the LRA), needle‐to‐ balloon time (18.2 ± 2.8 min vs. 17.8 ± 6.5 min for RRA & LRA respectively, *P* = 0.12), number of catheters, postprocedure vascular complications, in‐hospital reinfarction, and stroke/tran‐ sient ischemic attack (TIA) or death. We concluded that both right radial access and left radial access are safe and effective in primary PCI, as both approaches have a high success rate and comparable needle‐to‐balloon time [40].

A recent retrospective study done on 135 patients compared LRA vs. RRA in STEMI patients. Primary PCIs were performed for 85 patients using the right radial approach and 50 using the left radial approach. Results show that there was no significant difference in room procedural times, success rates, and comparable safety. But the authors attributed these results to the choice of LRA in patients known to be at risk for RRA failure (old age, female gender, lower body weight, and lower BMI). As in the patients of the LRA group, there were more females (40 vs. 20%, *P* = 0.02), significantly older (69.7 ± 14.8 vs. 60.0 ± 12.5 years, *P* < 0.0001), lower body weights (78.0 ± 16.3 vs. 95.1 ± 26.8 kg, *P* ≤ 0.0158), shorter stature (169.3 ± 10.8 vs. 173.9 ± 10.3 cm, *P* = 0.02), and lower BMI (27.2 ± 5.1 vs. 31.2 ± 7.7 kg m−2, *P* ≤ 0.01) [41].

A recent prospective study on 200 STEMI Chinese patients compared LRA vs. RRA. Primary PCIs were performed for 100 patients using the right radial approach and 100 using the left radial approach. Results show that there were no significant differences in the demographics and clinical characteristics for patients included in both groups. There was no significant dif‐ ference between the right radial and left radial regarding procedural success rate (98 for left vs. 94% for right; *P* = 0.28). But there was significant difference between the right radial and left radial regarding needle‐to‐balloon time (16.0 ± 4.8 LRA vs. 18.0 ± 6.5 min RRA; *P* = 0.02), fluo‐ roscopy time (7.4 ± 3.4 LRA vs. 8.8 ± 3.5 min RRA; *P* = 0.01), and CAK dose area product (51.9 ± 30.4 vs. 65.3 ± 49.1 Gy cm2 ; *P* = 0.04). Fu and colleagues attributed these results to the anatomi‐ cal advantage of LRA, which allows for quicker and easier delivery of a PCI device, such as a balloon or aspiration catheter. They also mentioned that all operators participating in this study had been well trained to perform the left radial PCI procedure before the study [42].

Another recent prospective study on 206 patients with acute myocardial infarctions who required emergency percutaneous coronary intervention and were divided into the follow‐ ing two groups: a group that underwent percutaneous coronary intervention through the left radial artery and other group that underwent percutaneous coronary intervention through the femoral artery. The times required for angiographic catheter and guiding catheter place‐ ments, the success rate of the procedure, and the incidence of vascular complications in the two groups were observed. Results show that there was no significant difference in cath‐ eter placement time or the ultimate success rate of the procedure between the two groups. However, the left radial artery group showed a significantly lower incidence of vascular com‐ plications than the femoral artery group (*P* < 0.05) [43].
