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CASE REPORT SALAMI ET AL COLONIC INJURY FROM PACING WIRES
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Fig 3. Electrocardiogram of patient 3 during chest pain attack showing complete right bundle-branch block and third-degree atrioventricular block with widespread ST segment depression and ST segment elevation in lead augmented vector right (aVR). (aVF ⫽ augmented vector foot; aVL ⫽ augmented vector left.)
Comment Both acute LMCA obstruction and dysfunction of mechanical aortic valves are emergencies requiring immediate aggressive treatment. We describe three cases of intermittent dysfunction of mechanical aortic valves presenting as chest pain followed by severe hemodynamic instability. Although the cases are similar to those reported by Mullenix and associates [1] and by Karagiannis and associates [2], electrocardiographic findings have been rarely reported [2]. We report the electrocardiographic presentations of acute dysfunction of aortic valve prosthesis related to perivalvular pannus ingrowth mimicking acute LMCA occlusion. The electrocardiographic changes associated with LMCA disease consisted of ST segment elevation in leads V1 and aVR, and widespread ST segment depression, associated with inverted T waves [3]. The same electrocardiographic pattern was described in our 3 patients with acute aortic regurgitation caused by dysfunction of a mechanical aortic valve; they might share the same mechanism of subendocardial ischemia. Extensive ischemia caused by sudden obstruction of LMCA impairs left ventricular relaxation. Visner and associates [4] showed that in conscious dogs, constriction of LMCA results in a significant decrease in the endocardial-to-epicardial flow ratio and a significant increase of end-diastolic left ventricular transmural pressure. The resulting increase in LV end-diastolic pressure induces severe subendocardial ischemia, and acute aortic regurgitation caused by dysfunction of a mechanical aortic valve results in an imbalance between myocardial oxygen supply and consumption. Increased heart rate and systolic wall stress augment myocardial oxygen demand. The increase in wall stress in acute aortic regurgitation is related to elevated left ventricular diastolic pressure and to acute left ventricular enlargement. Concomitantly, myocardial blood supply may be compromised because of reduced aortic root diastolic pressure and shortened diastolic period. The interplay between these opposing forces may result in acute myocardial ischemia. Because intramyocardial compressive forces are greatest in the subendocardium, and this region is farthest from the epicardial coronary arteries, the subendocardium is the most vulnerable myocardial region. This vulnerability may mani© 2012 by The Society of Thoracic Surgeons Published by Elsevier Inc
fest as ST segment depression in precordial leads maximally in leads V4 to V6 and as ST segment elevation in lead aVR because the latter lead is electrically opposite to precordial leads [5] and facing the left ventricular cavity [6]. In conclusion, for severely ill patients with a history of aortic valve replacement, acute dysfunction of the mechanical valve prosthesis should be suspected when the electrocardiogram shows widespread ST segment depression with inverted T waves and ST segment elevation in aVR mimicking acute occlusion of the LMCA. A redo operation seems to be the first choice in case of pannus formation.
References 1. Mullenix PS, Parsa CJ, Mackensen GB, Jollis JG, Harrison JK, Hughes GC. Pannus-related prosthetic valve dysfunction and life-threatening aortic regurgitation. J Heart Valve Dis 2008; 17:666 –9. 2. Karagiannis SE, Karatasakis G, Spargias K, Louka L, Poldermans D, Cokkinos DV. Intermittent acute aortic valve regurgitation: a case report of a prosthetic valve dysfunction. Eur J Echocardiogr 2008;9:291–3. 3. Yamaji H, Iwasaki K, Kusachi S, et al. Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography: ST segment elevation in lead aVR with less ST segment elevation in lead V(1). J Am Coll Cardiol 2001;38:1348 –54. 4. Visner MS, Arentzen CE, Parrish DG, et al. Effects of global ischemia on the diastolic properties of the left ventricle in the conscious dog. Circulation 1985;71:610 –9. 5. Nikus KC, Sclarovsky S. ST elevation in lead aVR as a sign of left main disease: perpetuating an error? Am J Cardiol 2004;94:542–3. 6. Yu PN, Stewart JM. Subendocardial myocardial infarction with special reference to the electrocardiographic changes. Am Heart J 1950;39:862– 80.
Colonic Injury From Temporary Epicardial Pacing Wires Mudasiru A. Salami, MRCS, FWACS, Richard J. Coleman, MD, FRCP, and Keith G. Buchan, FRCS North of Scotland Cardiothoracic Center and Department of Neurology, Aberdeen Royal Infirmary, Aberdeen, United Kingdom
A 72-year-old man who had undergone a three-vessel coronary artery bypass grafting, aortic valve replacement, and tricuspid valve repair became comatose 1 week after the procedure. Signs of intraabdominal sepsis developed 0003-4975/$36.00 doi:10.1016/j.athoracsur.2011.09.020
FEATURE ARTICLES
found. After the operation the patient had an uncomplicated recovery.
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CASE REPORT SALAMI ET AL COLONIC INJURY FROM PACING WIRES
6 days later, leading to laparotomy on his 12th postoperative day. The Intraoperative finding was a perforating injury to the transverse colon caused by the ventricular temporary pacing wires. A defunctioning double-barreled transverse colostomy was performed, after which the patient started to recover. He was discharged home 2 weeks later. (Ann Thorac Surg 2012;93:1309 –11) © 2012 by The Society of Thoracic Surgeons
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he placement of temporary atrial and ventricular epicardial pacing wires is common in patients undergoing cardiac surgical procedures. The main use of a temporary pacing system is to assist in the management of hemodynamically significant bradyarrhythmias and to suppress tachyarrhythmias or to optimize patients’ cardiac function in the perioperative period. Most temporary pacing wires are considered to be associated with low morbidity, but infrequent, and rarely catastrophic, complications have been reported. We report a case in which colonic injury was caused by the placement of ventricular temporary epicardial pacing wires.
FEATURE ARTICLES
A 72-year-old man was admitted electively for aortic valve replacement, tricuspid valve repair, and coronary artery bypass grafting on a background of longstanding severe aortic stenosis. He had severely impaired left ventricular function and severe pulmonary hypertension, and he was in chronic congestive heart failure preoperatively. He underwent aortic valve replacement on Jan 25, 2011 with a 25-mm Hancock II porcine valve (Medtronic Inc, Minneapolis, MN), tricuspid valve repair with a 36-mm MC3 ring (Edwards Lifesciences, Irvine, CA), and threevessel coronary artery bypass grafting. His initial recovery was good, but he started to become confused on the fourth postoperative day and was unconscious by the sixth day. A cranial computed tomographic (CT) scan was normal, and an electroencephalogram showed diffuse slow activity suggesting encephalopathy. At this stage, Accepted for publication Sept 2, 2011. Address correspondence to Mr Salami, North of Scotland Cardiothoracic Center, Aberdeen Royal Infirmary, Aberdeen, UK AB25 2ZN; e-mail:
[email protected].
Fig 1. Computed tomographic scans performed on (A) postoperative day 6 and (B) postoperative day 12. Note the development of gas in the ascending colonic wall (arrows), indicating imminent colonic necrosis and rupture.
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his severe encephalopathy was attributed to a temporary deterioration in renal function. No other factors were identified, although he had been given broad-spectrum antibiotic therapy in case of occult infection. He was admitted to the intensive therapy unit (ITU) and had a tracheostomy for artificial ventilation (although his gas exchange during the administration of face mask oxygen was normal). Signs of intraabdominal sepsis developed 12 days after the operation, and there was radiologic evidence of imminent large bowel necrosis (Fig 1). In retrospect, there was a small pocket of air in relation to the transverse colon on an abdominal CT scan undertaken 1 week previously (Fig 1). This had been mistakenly attributed to a recently removed mediastinal drain. His vague abdominal guarding on day 12 necessitated a repeat abdominal CT scan, which showed gas in the bowel wall (Fig 1) in addition to the previously noted pocket of intraperitoneal gas. At laparotomy, a penetrating injury to the transverse colon caused by the ventricular temporary pacing wires was noted. There was an associated area of localized peritonitis with ileus. A defunctioning double-barreled transverse colostomy was carried out. Thereafter, his condition steadily improved. He started to become alert about 26 hours after the colostomy, as observed during the evening ITU rounds. A week after the laparotomy he was tolerating a regular diet and had no residual neurologic problems. He was fully ambulant after a further 10 days and was allowed to go home shortly thereafter.
Comment Temporary wires are sutured routinely to the atrial or ventricular epimyocardium after open heart procedures. Ventricular pacing wires are inserted into the bare muscular portion of the anterior surface of the right ventricle, and the distal ends of the pacing wires are passed percutaneously to the left of the midline below the costal margin. The use of temporary epicardial pacing wires in cardiac operations is generally safe and simple, with low morbidity and mortality. The most common complication of temporary pacing wires is failure of atrioventricular sensing or capture [1]. The other complications are mainly those occurring during wire removal. Patients are at risk of ventricular
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2. Carroll KC, Reeves LM, Andersen G, et al. Risks associated with removal of ventricular epicardial pacing wires after cardiac surgery. Am J Crit Care 1998;7:444 –9. 3. Navia JL, Atik FA, Grimm RA, et al. Minimally invasive left ventricular epicardial lead placement: surgical techniques for heart failure resynchronization therapy. Ann Thorac Surg 2005;79:1536 – 44. 4. Del Nido P, Goldman BS. Temporary epicardial pacing after open heart surgery: complications and prevention. J Card Surg 1989;4:99 –103. 5. Price C, Keenan DJ. Injury to a saphenous vein graft during removal of a temporary epicardial pacing wire electrode. Br Heart J 1989;61:546 –7. 6. Gentry WH, Hassan AA. Complications of retained epicardial pacing wires: an unusual bronchial foreign body. Ann Thorac Surg 1993;56:1391–3. 7. Meier DJ, Tamirisa KP, Eitzman DT. Ventricular tachycardia associated with transmyocardial migration of an epicardial pacing wire. Ann Thorac Surg 2004;77:1077–9. 8. Oza PM, Reiling RB. Colonic perforation following intraoperative pacemaker implantation. PACE 2003;26:918 –9. 9. Davies NW, Sharief MK, Howard RS. Infection-associated encephalopathies: their investigation, diagnosis, and treatment. J Neurol 2006;253: 833– 45.
Reconstruction of Pulmonary Artery in a Newborn Using a Porcine Small Intestinal Submucosal Patch Fariba Chalajour, MD, Laura A. Barboza, MD, Lorenzo Boni, MD, Radhika Snyder, BA, Frank L. Hanley, MD, V. Mohan Reddy, MD, and R. Kirk Riemer, PhD Pediatric Cardiac Surgery Division, Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California
In this case report, we evaluated cellular structure and the growth potential of a porcine small intestinal submucosal patch used for pulmonary artery augmentation in a 20-day-old newborn with pulmonary atresia. The patch was resected 2 months postoperatively due to apparent abnormal wall thickening and evaluated by histologic and immunohistologic staining. (Ann Thorac Surg 2012;93:1311–5) © 2012 by The Society of Thoracic Surgeons
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pplication of biomaterial extracellular matrix (ECM) is a promising approach for the construction of autologous vascular graft in pediatric patients. Endothelialization of the luminal side of ECM followed by subendothelial recruitment of smooth muscle cells and formation of a vascularized connective tissue adventitia are essential for the construction of large vascular conduits similar to the patient’s native vessels. In pediatric patients, however, the growth capacity of the grafted substitute with the patient’s body is a
References
Accepted for publication Aug 24, 2011.
1. Farhad E, Tullo NG, Khalighi K. Natural history and predictors of temporary epicardial pacemaker wire function in patients after open heart surgery. Cardiology 2002;98:175– 80.
Address correspondence to Dr Riemer, Stanford University, Falk Cardiovascular Research Center, 300 Pasture Dr, Rm CV116C, Stanford, CA 94306-5407; e-mail:
[email protected].
© 2012 by The Society of Thoracic Surgeons Published by Elsevier Inc
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FEATURE ARTICLES
arrhythmias during epicardial pacing wire removal, sometimes necessitating electrocardiographic monitoring [2]. Navia and associates in their review of complications after temporary pacing wire use found a 0.04% incidence of major complications [3]. An earlier report by Del Nido and Goldman found a 0.4% rate of major complications, and 1 patient died of a pacemaker-related complication [4]. Those infrequent and rarely catastrophic complications include hemorrhage and tamponade from atrial and ventricular lacerations [4], whereas other workers have also reported injuries to saphenous vein grafts [5], retained pacing wires presenting as a bronchial foreign body [6], and transmyocardial migration of an epicardial pacing wire causing ventricular tachycardia [7]. Colonic injury secondary to inadvertent transperitoneal passage of pacing wires is very rare. We are aware of only one report in the literature [8].This was in a 73-yearold man in whom increasing abdominal free air developed 1 week after a surgical procedure for aortic valve replacement and coronary bypass grafting with temporary pacemaker implantation. As with our patient, laparoscopic exploration revealed that the pacemaker wires had passed through the transverse colon. The technique used for pacing wire placement through the abdominal wall is the key consideration in avoidance of a transverse colon injury. The ventricular pacing wires were placed in this patient by a highly experienced cardiac surgeon. The technique involved finger dissection below the rectus muscle with palpation of the costal margin and bimanual palpation of the pacing wire track before the needle was actually passed. Despite such careful attention to detail, this injury still occurred. We believe this type of iatrogenic complication is to be regarded as a very rare event, which cannot be completely guarded against. Encephalopathy (mental confusion with a fluctuating conscious level) is a common presentation of toxic or metabolic abnormalities or both, especially in the elderly. Severe encephalopathy, as in this case, should always raise the possibility of occult infection [9]. Diagnosis may be difficult if evidence of infection is masked by antibiotic therapy and the site of infection has not been identified. In this case, the systemic response to localized peritonitis turned out to be a major factor, but diagnosis was delayed because of the lack of abdominal signs and the rarity of this complication. In conclusion, temporary pacing wire injury to the transverse colon is worth considering as a cause of clinical deterioration in patients after cardiac surgical procedures. Its presentation may not be immediately referable to the abdomen.
CASE REPORT CHALAJOUR ET AL GROWTH POTENTIAL OF SIS VASCULAR PATCH
