BACKGROUND AND AIMS
Treating chronic total occlusions (CTO) by the antegrade approach requires appropriate devices and skill in resource-limited settings. Good guide-catheter support is crucial.1,2 Patients with diabetes and narrower radial arteries are prone to spasm with larger guiding catheters, and may benefit from a slender approach to percutaneous coronary intervention (PCI).2,3 However, in resource-constrained environments, restricted finances and accessibility limit the use of regular hardware necessary for successful CTO intervention, especially via the transradial approach (TRA). The authors investigated whether a slender technique by TRA using 5 French (Fr) guide and a smaller profile balloon is a feasible option for successful CTO intervention by antegrade approach in diabetics with narrower radial arteries.
MATERIALS AND METHODS
This was a single-centre, single-operator, retrospective observational study conducted at the authors’ high-volume radial centre from July 2018 to June 2020. Data were derived from hospital records and the cardiac catheterisation laboratory database. Statistical analysis was performed using SPSS version 16 (IBM, Armonk, New York, USA) and variables were compared using the Student’s t-test and the chi-squared test. A p-value <0.05 was considered statistically significant.
RESULTS
A total of 249 CTO PCI were attempted transradially. Given limited access to hardware, all procedures were performed using the antegrade wire escalation (AWE) technique, with 166 (67.2%) performed by 5 Fr guide and 81 (33.8%) by 6 Fr guide catheter. Nearly 75% of cases were of J-CTO score ≥2, almost equally observed between 5 Fr (71.6%) and 6 Fr (74.1%) groups. In total, 53.1% were CTO of the right coronary artery. Furthermore, 41.3% and 5.6% were CTO of the left anterior descending artery and left circumflex artery, respectively.
Biradial injection was performed in most cases wherever applicable, in both groups. A small-profile balloon, usually a 1.25×5 mm semi-compliant balloon (76.7% versus 72.8% for 5 Fr and 6 Fr, respectively) or microcatheter (28.3% versus 27.1% for 5 Fr and 6 Fr, respectively), was used for support. Procedural success rates were 72.7% versus 74.1% for 5 Fr and 6 Fr, respectively (p=0.82). Crossover to larger backup guides was 3.2% versus 2.9% for 5 Fr and 6 Fr, respectively (p=0.62), with a single 6 Fr case switched to femoral access. Active support was achieved by deep intubation of guide and making α, γ, or ε loops in the majority of cases of the 5 Fr group, where extra support was necessary. Successful crossing by workhorse CTO guidewires was achieved by Gaia First (Asahi Intecc, Aichi, Japan; 68.6%), Gaia Second (12.3%), and thin intermediate support hydrophilic PT2 wire (Boston Scientific, Marlborough, Massachusetts, USA; 19.1%).
A single coronary perforation occurred in the 6 Fr group, requiring emergency surgical intervention. No access site complications were noted in either group. Contrast volume was numerically lower in the 5 Fr group (152 versus 165 mL; p=0.26). Fluoroscopy time and procedural times (5 Fr: 34.31 min; standard deviation [SD]: ±17.2 min; 6 Fr: 33.4 min; SD: ±14.2; p=0.67) were comparable between the two groups.
CONCLUSIONS
5 Fr guide is a feasible approach for CTO PCI by AWE, with success rates comparable to other studies.3 Advantages include reduced contrast volumes and radial spasm in narrow arteries. Slender approach allows for better active support by TRA, complemented by the use of a low-profile balloon, instead of routine use of a microcatheter in resource-tailored situations. This slender approach is supported by techniques of deep intubation, as well as α, γ, and ε loops.1 Despite certain limitations in cases of complex bifurcation lesions, and the use of adjunctive devices such as atherectomy,4 slender TRA by 5 Fr guide catheter offers a feasible approach to CTO PCI by AWE, especially among patients with diabetes and narrow radial arteries.
