Abstract
A 69-year old male was referred to our hospital for the treatment of coronary artery disease. Preoperative computed tomography (CT) revealed an abdominal aortic aneurysm (AAA) and a giant tumour of the left kidney. He underwent off-pump coronary artery bypass grafting (OPCAB) prior to aneurysmectomy and nephrectomy. Temporary epicardial pacing wires (TEPWs) were placed on the right atrium and right ventricle. The bipolar ventricular wire was removed and the unipolar atrial wire was cut flush with the skin surface on postoperative day 5. CT 7 days after the OPCAB procedure revealed a retained TEPW sutured to the right atrial wall. One month later, the patient underwent a repair of the AAA and left nephrectomy. We found that a TEPW had migrated inside the AAA intraoperatively. The retained TEPW was thus no longer observed on postoperative CT. Migration of the atrial pacing wire through the aortic lumen was suspected, although the detailed mechanism is unknown. This is the first reported case of a migrated temporary pacing wire into the aorta under noninfectious conditions.
CASE REPORT
Temporary epicardial pacing wires (TEPWs) have been used routinely in cardiovascular surgery since the 1960s. The migration of TEPWs is a rare complication, and typically involves migration into the right side of the heart. Only 2 cases showing migrated TEPWs into the left side of the heart under infectious conditions have been reported so far. We herein report a case of migration of the TEPW into the abdominal aorta 1 month after off-pump coronary artery bypass grafting (OPCAB) under noninfectious conditions.
A 69-year old male previously visited the hospital for dyspnoea and leg oedema. Coronary angiography and left ventriculography revealed three-vessel disease with old anteroseptal myocardial infarction. He was admitted to our hospital and preoperative computed tomography (CT) revealed an infrarenal abdominal aortic aneurysm (AAA) and a giant tumour of the left kidney. The size of the AAA was 51 mm with a draped aorta sign, and the size of the tumour was 140 mm. Isolated OPCAB was initially performed. The left internal thoracic artery was sutured to the left anterior descending artery and the right gastroepiploic artery was sutured to the posterior descending branch and obtuse marginal branch in sequential fashion. A unipolar TEPW was fixed to the right atrium (RA) with Prolene 5-0 (Ethicon, Inc., Somerville, NJ, USA) and a bipolar TEPW was then sutured directly to the right ventricular (RV) wall. After performing the atrial procedure, we used a fixation method where the TEPW could be easily pulled out. The TEPW was embedded in the fold of the right atrial wall created by the double epicardial stitching using Prolene 5-0. The postoperative course was uneventful, and we tried to remove the TEPWs on postoperative day 5. A TEPW on the RV was easily removed, but a TEPW on the RA was cut and left in situ due to resistance. Postoperative 3D CT revealed all bypass grafts to be patent and a retained TEPW was also identified (Fig. 1A and B). The root of the retained TEPW was in the subcutaneous tissue, and the tip of the TEPW was close to the anterior wall of the ascending aorta. One month later, the patient underwent repair of the AAA and left nephrectomy concomitantly under laparotomy. The patient had no fever and the C-reactive protein level was 0.27 mg/dl before the second operation. When the aneurysm was opened, there was a TEPW in the aneurysm. The root of the TEPW was clamped by proximal clamp forceps, and the tip of the TEPW was directed towards the aortic bifurcation. After the TEPW was removed, graft repair of the AAA and nephrectomy was performed. The removed TEPW measured 25 cm in length and barbs of the insulating coat to prevent the wire from slipping out were present. The patient had an uneventful postoperative course and postoperative CT revealed the disappearance of the retained TEPW which had been sutured on the RA wall (Fig. 1C).
Computed tomography 7 days after the OPCAB procedure revealed a retained TEPW sutured to the right atrial wall (A and B). However, it was no longer present after the second operation (C). OPCAB: off-pump coronary artery bypass grafting; TEPW: temporary epicardial pacing wires.
DISCUSSION
TEPWs have been routinely used after cardiac surgery. They have been found to be valuable for stabilizing arrhythmias, such as bradycardia, and for maintaining cardiac output. On the other hand, catastrophic complications, such as cardiac arrhythmia, injuries to saphenous vein grafts, atrial and ventricular lacerations resulting in haemorrhage and cardiac tamponade, have sometimes been reported following TEPW removal [1]. Carroll et al. reported that 7% of patients had non-sustained ventricular tachycardia during removal of TEPWs [2]. Therefore, TEPWs should be removed postoperatively by gentle traction, and they can be cut flush with the skin if surgeons feel resistance to removal. Migration of retained TEPWs is rare, but problematic. Almost all cases of TEPW migration have been reported on the right side of the heart a few years after a previous operation. Migrations of TEPWs into the RA, RV, pulmonary artery, bronchus and lung have been reported, sometimes in association with infectious conditions [3]. Migration into the left side of the heart is extremely rare, and only 2 such cases have been previously reported in the literature. One case reported a migrated TEPW into the carotid artery complicated with prosthetic valve endocarditis 2 years after the previous operation [4], while another showed migration into the ascending aorta after 9 months under infectious conditions [5]. There are three interesting points in our case. Firstly, there were no signs of infection after the first operation. He had no fever and the C-reactive protein level was 0.27 mg/dl before the second operation. Secondly, the mode of migration into the left heart system is not clear. Juchem et al. suggested that a possible entrance into the left heart system may be through the right superior pulmonary vein or the roof of the left atrium [4]. Conversely, Guerrieri Wolf et al. reported a case of direct perforation into the ascending aorta [5]. Thirdly, the migration was completed within a month. In our case, the tip of the TEPW was located on the anterior wall of the ascending aorta and the migration into the AAA occurred within a very short period of time. We therefore speculate that the most likely mechanism would be a direct perforation into the ascending aorta. TEPWs are usually inconspicuous on an X-ray image. If the second operation had not been performed, we would not have found the migrated TEPW. Furthermore, there was no indication in the blood test or abdominal X-ray, and the patient had no symptoms just before the abdominal surgery. It is preferable to remove such a wire whenever possible. If TEPWs are retained after cardiac surgery, then a careful follow-up is mandatory. The migration of retained TEPWs into the left side of the heart can occur even under noninfectious conditions.
Conflict of interest: none declared.
REFERENCES
