The distal radial approach (DRA) is suggested to have benefits over the conventional radial approach (CRA) in terms of local complications and comfort of both patient and operator. Therefore, we aimed to compare the feasibility and safety of DRA and CRA in a real life population. We conducted a prospective, observational multicentric trial, including all patients undergoing coronary procedures in September 2019. Patients with impalpable proximal or distal radial pulse were excluded. Thus, the choice of the approach is left to the operator discretion. The primary endpoints were cannulation failure and procedure failure. The secondary endpoints were time of puncture, local complications and radial occlusion assessed by Doppler performed one day after the procedure. We enrolled 177 patients divided into two groups: CRA (n = 95) and DRA (n = 82). Percutaneous intervention was achieved in 37% in CRA group and 34% in DRA group (p = 0.7). Cannulation time was not significantly different between the two sets (p = 0.16). Cannulation failure was significantly higher in DRA group (4.8% vs 2%, p < 0.0008). Successful catheterization was achieved in 98% for the CRA group and in 88% for the DRA group (p = 0.008). Radial artery occlusion, detected by ultrasonography, was found in 3 patients in the CRA group (3.1%) and nobody in the DRA group (p = 0.25). The median diameter of the radial artery diameter was higher in the DRA than the CRA group (2.2 mm vs 2.1 mm; p = 0.007). The distal radial approach is feasible and safe for coronary angiography and interventions, but needs a learning curve.

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Purpose: To formulate and study the kinetics of delivery and retention of three halofuginone (HF) gels via different wall layers of an ex vivo model mimicking urethral tissue. Methods: Three HF hydrogels (a, b and c) of the same concentration (0.03 % w/v) incorporating different levels of sodium carboxymethyl cellulose (Na-CMC), were prepared. The viscosity of the different gels was studied at 37 °C and at room temperature. The release of HF from these hydrogels and its diffusion into urethral tissue were evaluated using a new ex vivo model mimicking human urethral tissue. The amount of HF was determined by HPLC method. Results: The release of HF increased with increasing viscosity and duration of contact. Gel c showed the best drug release after 2 h of diffusion, with 65.7 % HF in the wall of the ureter. The model showed a uniform distribution of the drug throughout the ureter tissue. In comparison, HF was not detected in the receiver compartment until 2 h. Conclusion: Topical HF gel application is a suitable solution for the potential treatment of urethral stricture and/or recurrence. The formulation and characterization of the ureter model should facilitate the development of new therapeutics for urethral diseases.

A new high-performance liquid chromatography method was developed to study the diffusion of halofuginone in the wall of the ureter. The human ureter extracts were prepared by trypsin digestion of the tissues followed by liquid-liquid extraction using the isopropanol after precipitating the proteins. The method used a reversed-phase C18 column with a mobile phase delivered to the analytical column according to a gradient program starting at a composition of ammonium acetate (pH 4.7; 10 mM)-acetonitrile-triethylamine (70:30:0.2, v/v/v) and linear changes to 90% of acetonitrile at 11 min. Liquid-liquid extraction proved to be selective for the HFG and provided a high recovery rate of 97.7%. The HPLC method was successfully validated by applying the novel validation protocol using the accuracy profile based on a new concept, that of the total error. The protocol V4, with five levels of concentration and 105 trials, was selected according to the algorithm designed by the SFSTP 2003 committee. Acceptance limits were set up at  20%, while the risk was settled at 5%. The method was found accurate over a concentration range of 0.2-10 µg/ml. The limit of detection for HFG was 0.06061 µg/ml. In order to demonstrate the applicability of this method in ex vivo application, the quantification of HFG in the wall was applied to study its distribution from a gel (0.03% w/w of HFG) in the human ureter.