The authors Kim et al. [16] published a series of 150 selected patients who had angiography or PCI with 6 French catheters via the left box approach, 14 success rate was 88%. The main reasons were a failure in puncture and failure in advancing the guidewire due to the tortuosity of the artery and vasospasm. In the experience of Valsecchi et al. [17], all 52 patients underwent diagnostic or procedural intervention through dTRA access. The overall viability was 90%. The failures occurred due to occlusion of the proximal radial artery and distal hypoplastic/vasospastic artery.
In the context of performing the puncture on the patient’s left side, it does not impose additional difficulties [18]. An observation to be taken in these cases is that, when the patient has some degree of respiratory distress and uses abdominal breathing more intensely, there is a lot of hand oscillation at this time, which can prevent not the correct palpation of the wrist, but its puncture. As for the viability and incidence of complications, it has already been demonstrated that there are no differences between the two sides, despite the slight differences in favor of the radial left in terms of shorter fluoroscopy time and less volume of contrast used [21]. This small disproportion is not due to the fact that we find more tortuosity when navigating the Brachiocephalic Trunk, which does not occur on the left side [22].
An advantage of the dTRA route is to preserve the conventional local radial puncture system on the wrist, as the need for multiple procedures on the same patient is becoming more and more frequent, due to increased life expectancy, as well as increased comorbidities that contribute to the development of atherosclerotic disease [22]. There is no tissue or vascular trauma in the usual place, nor does it suffer the effects of prolonged hemostatic compression or even with excessive intensity. However, a relevant perception during patient selection was that, in many individuals who had a palpable radial pulse at the wrist, the pulse in the anatomical region. The snuff box region was very thin or imperceptible [22].
The disadvantage of the vessel’s smaller caliber, which certainly decreases eligibility for the technique, has led us to assume that it may not be accessible to become a standard in cardiology interventions, but a good option in selected cases, especially on the left side. Another advantage that emerges from the present study is that the dTRA access security profile is similar to the conventional TRA profile since a minimal incidence of hemorrhagic complications was detected and there was no pulse loss [21].
The maintenance of the wrist appears as an interesting advantage due to the possibility of repeating the puncture in the same place, when necessary. Due to the similarity of the advantages of the two techniques, dTRA access can become another access route in which there will be the possibility of early discharge, even on the same day. Data from the Brazilian reality are already beginning to confirm the safety of this strategy, as long as an observation period is observed, approximately 6 hours are observed in selected patients [22].
The incidence of radial artery occlusion (RAO) and hemorrhagic events with dTRA has not been fully elucidated. Thus, a study in Japan investigated the effects of using dTRA on RAO and post-procedure hemorrhage. From April 2018 to July 2018, 228 consecutive patients undergoing coronary angiography or intervention through dTRA in two hospitals were analyzed. The rate of RAO, changes in the diameter of the forearm and distal radial artery, and cross-sectional area after the dTRA (1 day and 1 month) on vascular ultrasound and incidence of hemorrhagic complications were investigated. RAO in the forearm and distal occurred in 1 (0.4%) and 8 (3.1%) patients in 1 month, respectively. There were no bruises on the forearm. The ultrasound findings indicated that the diameter of the radial artery and the cross-sectional area was significantly larger after the dTRA (p <0.001). The diameter of the distal radial artery and the cross-sectional area in the anatomical snuffbox were also significantly larger after the dTRA (p <0.001). Therefore, dTRA was associated with a low incidence of RAO at the puncture site and in the forearm, post-procedure dilation of the radial artery, and no hemorrhagic complications that extended to the forearm [23].
In addition, the ldTRA approach is a new technique for coronary intervention. This technique is convenient for specialists to operate and is welcome for right-handed patients. The anatomical snuffbox and the first intermetacarpal are two puncture sites available based on the anatomy of the hand. In technical aspects, the main differences between the left distal transradial approach and the conventional transradial approach are the patient’s special position, puncture procedure, choice of the sheath, and hemostasis methods. According to preliminary data, this technique is viable and safe and has a low rate of complications, including occlusion of the radial artery in the forearm. The left distal transradial approach is a very promising strategy for coronary intervention and deserves further exploration [24].
In addition, another study analyzed that dTRA is associated with reduced rates of radial artery occlusion, ischemic events in the hands, as well as greater patient comfort, faster periprocedural management, and cost benefits. Our preliminary experience with dTRA for diagnostic cerebral angiography demonstrates excellent viability and safety in combination with relative efficiency [25].