br Results In all patients no abnormalities

Results In all patients, no abnormalities were found in the left axillary, left subclavian, or left brachiocephalic veins, such as blood vessel occlusion or stenosis. The procedure time was 138.6±41.8min in the conventional puncture group (Group A) and was 109.8±23.2min in the catheter-guided puncture group (Group B). There was a significant reduction in the procedure time in the catheter-guided puncture group (Group B) compared with the conventional puncture group (Group A; p=0.016; Table 2). In 5 patients in the catheter-guided puncture group (Group B) who were suspected to have venous collapse due to scarce blood backflow during the puncture, successful puncture was achieved easily by dilating the vein with 20-mL physiological saline flushes through the catheter. No patients in either group had pneumothorax, hematoma, or any other complications.
Discussion Venipuncture is an essential technique that is utilized for pacemaker implantation procedures. In the past, subclavian venipuncture was typically employed. However, due to the narrow space between the stock dilution calculator and the first rib, as well as the tense costoclavicular ligament, subclavian venipuncture is often associated with problems such as breakage of the pacemaker lead [1]. As an alternative to subclavian venipuncture, C.L. Byrd established an extrathoracic puncture method in 1993 and reported a 98% success rate in lead insertion without any insertion-associated complications [1]. However, in the same study, 3 out of the 213 patients had anatomical problems, such as blood vessel occlusion or stenosis of the axillary through the subclavian veins, which made lead insertion difficult [1]. Subsequently, another extrathoracic puncture technique involving imaging of the axillary vein was reported, which is our currently used method [2]. An improvement of this method by insertion of a Pigtail catheter as a marker to guide extrathoracic puncture was also described [3]; however, the Pigtail catheter has the tendency to become caught without advancing into the left subclavian vein beyond the venous valve, which is located in the transition between the left brachiocephalic and the left subclavian veins. Therefore, we instead employ a JR40 catheter as a marker to guide extrathoracic puncture. Another puncture method that is performed under the guidance of imaging in the LAO30 position was reported by Harada et al. in 2005 [4]. In the posteroanterior (PA) view, the puncture needle is not located parallel to the direction of the X-ray beam, making it difficult to precisely determine the position of the puncture needle. Under such circumstances, there is a possible risk of pneumothorax development. Using the guidance of imaging in the LAO30 position, the puncture needle can be led in the direction that is parallel to the X-ray beam, towards the area where the axillary vein crosses the anterior portion of the first rib, thereby minimizing the risk of pneumothorax occurrence. In addition, use of the JR40 catheter enables imaging-based confirmation of the positions of the left subclavian, left brachiocephalic, and left brachiocephalic veins, which can minimize the failure of securing target blood vessels due to anatomical abnormalities. Possible cases of venous collapse due to dehydration in the subclavian or axillary veins have been reported and identified by venous ultrasound [5]. Moreover, since the venous valve located between the left brachiocephalic and left subclavian veins is also very close to the area where the axillary vein crosses the anterior portion of the first rib, the inserted wire can get caught while pointing in the opposite direction; however, this problem can be prevented by flushing physiological saline through the catheter, which facilitates opening of the valve. Other insertion techniques have been recently described, including the cut-down method and ultrasound-guided puncture. The cut-down method requires somewhat skilled manipulation, as it is difficult to identify the groove that is located between the pectoral major muscle and the deltoid muscle, particularly in obese patients. A physician specializing in cardiovascular internal medicine may find this cut-down method to be more challenging than a surgeon specializing in cardiovascular surgery would, as this is a relatively invasive method. Although ultrasound-guided puncture has recently been recommended by experts in pacemaker-related academic societies and research groups, this method requires expertise in differentiating the subclavian vein from the subclavian artery and in analyzing diagnostic ultrasound images, a catheterization laboratory that is equipped with an ultrasound instrument and other necessaries, and an aseptic technique [6]. Due to the relatively complicated nature of this procedure, the ultrasound-guided puncture method is not commonly utilized.