4Fr in 5Fr sheathless technique with standard catheters for transradial coronary interventions: technical challenges and persisting issues.

Objectives: To evaluate the feasibility and potential benefits of performing sheathless 5Fr transradial percutaneous coronary interventions (PCI) using 4Fr diagnostic catheters as dilators.

Background: There is a direct association between artery-catheter mismatch and risk of radial artery occlusion.

Methods: We recruited 130 patients who underwent 4Fr sheathless diagnostic angiography with super torque (Cordis Corporation, USA) catheters followed by ad hoc PCI. To facilitate skin and vessel penetration, the Judkins right catheter (110 cm) was inserted inside the 5Fr guiding catheter (100 cm) as dilator.

Results: The mean age of patients was 63±12 years with 74% of males. Unfractionated heparin monotherapy was used in 84%, bivalirudin in 12%, and platelet glycoprotein 2b/3a inhibitors in 13%. Right radial artery was used in 99%. In three cases, no PCI was performed (FFR) and in two (1.5%) cases, a sheath was required after guiding catheter insertion due to local bleeding. In six cases (4.6%), upscale to 6Fr sheathed approach was required. No spasm occurred. Overall procedural success was achieved in 114/119 (96%) cases, including left main PCI, bifurcation PCI in 10 (8%) cases, CTO in 5 (4%) and IVUS use in 6 (5%) cases. Immediately after hemostasis completion, duplex ultrasound showed normal flow in 76%, occlusive thrombus in 13%, pseudo-aneurysmal dilatation in 11% and local hematoma surrounding puncture site in 20%. Hemoglobin dropped from 138±19 g/l to 131±16 g/l 4-6 hours after PCI.

Conclusion: Using 4Fr diagnostic catheters as dilators, simple and complex PCI can be performed with standard 5Fr guiding catheters as sheathless techniques. However, suboptimal transition between diagnostic and guiding catheters likely creates radial artery trauma leading to frequent occlusive thrombus and hematoma surrounding the radial artery.