Safety and Efficacy of Four Different Diagnostic Catheter Curves Dedicated to One-Catheter Technique of Transradial Coronaro-Angiography—Prospective, Randomized Pilot Study. TRACT 1: Trans RAdial CoronaryAngiography Trial 1

Transradial coronaro-angiography (TRA) can be performed with one catheter. We investigate the efficacy of four different DxTerity catheter curves dedicated to the single-catheter technique and compare this method to the standard two-catheter approach. For this prospective, single-blinded, randomized pilot study, we enrolled 100 patients. In groups 1, 2, 3, and 4, the DxTerity catheters Trapease, Ultra, Transformer and Tracker Curve, respectively, were used. In group 5 (control), standard Judkins catheters were used. The study endpoints were the percentage of optimal stability, proper ostial artery engagement and a good quality angiogram, the duration of each procedure stage, the amount of contrast, and the radiation dose. The highest rate of optimal stability was observed in groups 2 (90%) and 5 (95%). Suboptimal results with at least one episode of catheter fallout from the ostium were most frequent in group 1 (45%). The necessity of using another catheter was observed most frequently in group 4. The analysis of time frames directly depending on the catheter type revealed that the shortest time for catheter introduction and for searching coronary ostia was achieved in group 2 (Ultra). There were no differences in contrast volume and radiation dose between groups. DxTerity catheters are suitable tools to perform TRA coronary angiography. The Ultra Curve catheter demonstrated an advantage over other catheters in terms of its ostial stability rate and procedural time.

Diagonally Implicit Block Backward Differentiation Formula with Optimal Stability Properties for Stiff Ordinary Differential Equations

This paper aims to select the best value of the parameter ρ from a general set of linear multistep formulae which have the potential for efficient implementation. The ρ -Diagonally Implicit Block Backward Differentiation Formula ( ρ -DIBBDF) was proposed to approximate the solution for stiff Ordinary Differential Equations (ODEs) to achieve the research objective. The selection of ρ for optimal stability properties in terms of zero stability, absolute stability, error constant and convergence are discussed. In the diagonally implicit formula that uses a lower triangular matrix with identical diagonal entries, allowing a maximum of one lower-upper (LU) decomposition per integration stage to be performed will result in substantial computing benefits to the user. The numerical results and plots of accuracy indicate that the ρ -DIBBDF method performs better than the existing fully and diagonally Block Backward Differentiation Formula (BBDF) methods.