Ichiro Michishita， Cardiovascular Division， Department of Internal Medicine， Yokoh- ama Sakae Kyosai Hospital Federation of National Public Service Pe- rsonnel Mutual Aid Associations

    OBJECTIVES This study examined the efficacy of the type-M Sheathless guiding catheters (GC) with novel variable curve for trans-radial intervention (TRI).

    BACKGROUND The Sheathless GC with novel variable curve was developed for TRI firstly because the Sheathless GC itself is advantageous to smaller outer diameter equal to that of a 2F-downsized sheath introducer for TRI. Secondly the single GC can be adapted to almost every coronary ostium for the help of the variable curve controlled by the inner dilator and guidewire without changing catheters. Thirdly the GC owns some spring effect at the second variable curve leading to more back-up for TRI.

    METHODS In clinical practice of our hospital， 188 cases in total were applied to sheathless GCs for TRI with ad-hoc fashion. Left heart catheterization was performed according to the standard Seldinger technique for all patients. A 4 or 5 F sheath introducer was placed in the right radial artery. At the sheath insertion， 3000 units of heparin were administered intravenously. After usual coronary angiography using 4 F or 5F diagnostic catheters， in case of PCI， the sheath was exchanged to 6 or 7 F Sheathless GCs with the inner sheath through a 0.035-inch guidewire under fluoroscopy. Selection of GC in the group of usual Sheathless guiding catheters was 3 experienced doctors" choice in our catheter laboratory. In the group of usual Sheathless guiding catheters， Judkins Left (JL) 3.0， JL 3.5， JL 4.0， Judkins right (JR) 3.5， JR 4.0， Power Backup (PB) 3.5 and PB 4.0 GCs were used. In the group of TYPE-M guiding catheters， only the GC in question was used for consecutive 62 patients by a single doctor. The backup force and coaxiality of GCs were measured in a glass model of coronary artery and cardiovascular system filled with heated water at 37 ℃. The variable-curve， PB， JL 4.0ST and JR 4.0 GCs with the same size and were provided for examination. The data of each catheter for backup force were derived from measurement of maximal load induced by pushing a balloon catheter and advanced distance of the balloon catheter until displacement of the GC from the coronary ostium against action and reaction in the model of the coronary system. For examination of the left coronary system， the variable-curve with usual and super positions， PB and JL 4.0ST GCs were engaged into the left coronary ostium via the innominate and right subclavian arteries like the right radial approach. A 0.014-inch Neos Soft guidewire was placed into the left coronary artery in each experiment. A 3.25 x 20 mm-sized Ma"sla Just balloon catheter was automatically pushed forward by a motor drive with a push-pull gage at 100 mm/min. The advanced distance and maximal load of the balloon catheter were measured until displacement of the GC from the coronary ostium. Each experiment was repeated 10 times in each GC. For examination of the right coronary system， the variable-curve with usual and super positions， and JR 4.0 GCs were engaged into the right coronary ostium. Other conditions were the same as those in the left coronary system. 

    RESULTS In the clinical study， 188 cases were applied to Sheathless GCs in total. In the group of usual guiding catheters (126 cases)， 9 cases (5%) needed exchanging guiding catheters， in whom 8 cases (PB 3.5 in 5 cases， PB 3.0 in 1 case， JL 3.5 in 1 case and AL 0.75 in 1 case) were exchanged because of poor engagement and one case (JL 3.5) was exchanged because of poor backup. In the group of the TYPE-M Sheathless guiding catheter for consecutive 62 cases， all cases were applied successfully without any exchanging guiding catheters. In the left coronary system， the variable-curve GC showed significantly the most advanced distance (up to end) of the balloon catheter (P<0.05) and the least load for the balloon catheter (P<0.05) among tested GCs including JL 4.0ST， Power backup and the variable-curve GC in the in-vitro study. In the right coronary system， the variable-curve GC showed significantly more advanced distance (up to end) of the balloon catheter than that of JR 4.0 GC (P<0.01) and less load for the balloon catheter than that of JR 4.0 GC (P<0.01).

    CONCLUSIONS The Sheathless universal GC with the novel variable curve is efficacious for TRI to make the procedure better， safer and easier because of wide adaptability to almost all coronary ostium and stronger backup.