Abstract
Objective: Post-operative ductal aneurysm is a rare but fatal condition. We retrospectively analyzed the clinical profile of post-operative ductal aneurysm and outcome of their repair with different surgical approaches. Methods: From January 1976 to December 2002, 13 patients underwent repair of post-operative ductal aneurysm. The case data of the patients operated were analyzed and survivors were followed-up. Three patients underwent repair through left thoracotomy, femoro-femoral bypass and 10 patients underwent patch aortoplasty through sternotomy using total circulatory arrest with minimal dissection. Among the sternotomy group, nine patients had midline sternotomy and one patient had transverse sternotomy with the patient in semi-right-lateral position. Hemoptysis (69%) was the commonest presenting symptom. Ten patients had ligation and three patients had division of ductus. Mean age at ductus interruption was 13.7±8.2 years; mean time interval for development of aneurysm was 3.6±4.2 years; mean age at aneurysm surgery was 16.9±8.8 years. Residual left to right shunt was detected in 6 (46%) patients. Results: Three patients repaired through left thoracotomy with femoro-femoral bypass died during surgery due to rupture of aneurysm during dissection and profuse bleeding. Thirty-day survival in patients operated through sternotomy using circulatory arrest was 90% (9/10). Two patients required additional incision in second left intercostal space along with midline sternotomy, for access to descending thoracic aorta. Of these two patients, one patient had bleeding from friable aorta and died; another patient developed left hemiplegia; circulatory arrest time was prolonged in this patient. Mean follow-up period was 9.6±5.3 years. Persistent left vocal cord palsy was seen in one patient. One patient was lost to follow-up after 3-years. Remaining eight patients were asymptomatic at follow-up. Conclusion: Repair of postoperative ductal aneurysm through left thoracotomy is difficult due to extreme fragility of aneurysm and because of reoperative difficulties. The immediate and long-term outcome of the cases operated through sternotomy using total circulatory arrest with minimal dissection is good. Midline sternotomy limits approach to descending thoracic aorta that can be circumvented by using transverse sternotomy with semi-right-lateral positioning of the patient.
1 Introduction
Aneurysm following interruption of patent ductus arteriosus or post-operative ductal aneurysm is a rare but potentially fatal complication [1]. Most of them are pseudo aneurysms and develop following ligation of ductus, but true aneurysms are also seen [1]. The reported mortality following surgery varies from 26 to 54% [1,2]. The use of midline sternotomy, cardiopulmonary bypass and total circulatory arrest for successful management of two cases was first reported in 1988 [3]. We undertook a retrospective study of all cases of post-operative ductal aneurysm operated at this institute till December 2002 and analyzed the short-term and long-term outcome of patients who underwent surgery with different surgical approaches.
2 Patients and methods
After obtaining approval from institutional review board, the data of all the patients with post-operative ductal aneurysm operated from January 1976 to December 2002 (27-year period) were retrospectively analyzed. The data analyzed were demographic variables, clinical features, type of initial patent ductus arteriosus surgery, age at patent ductus arteriosus interruption, and interval for subsequent development of clinical features, surgical approach used, death and other complications.
Patient demographics, clinical features and operative strategy
Thirteen-patients underwent repair of post-operative ductal aneurysm. Hemoptysis (8 patients, 69%) was the commonest presenting symptom (Table 1). Low-grade fever (4 patients), hoarseness of voice (4 patients) and failure to thrive (1 patient) were other symptoms. Seven-patients were in New-York Heart Association class II and six-patients were in class III. Ten-patients had ligation and three had division of ductus. Mean age at ductus interruption was 13.7±8.2 years; mean time interval for development of aneurysm was 3.6±4.2 years; mean age at aneurysm surgery was 16.9±8.8 years. Residual left to right shunt was detected in 6 (46%) patients. Chest X-ray suggested the presence of aneurysm in all the patients and aortogram confirmed the diagnosis (Fig. 1) in 12 patients. In one case, diagnosis was made at fluoroscopy as the patient presented with massive hemoptysis. Twelve cases were operated electively while one case was operated emergently for massive hemoptysis. Three-patients had mean pulmonary artery pressure of more than 50 mmHg (range 55–75mmHg, mean 58±12 mmHg). The overall mean pulmonary artery pressure was noted to be 37±12 mmHg.
2.1 Operative technique using left thoracotomy with femoro-femoral bypass
Three-patients were operated using this technique. The aneurysm was approached via left posterolateral thoracotomy through the bed of the 4th rib in all cases. The operative plan was to isolate, resect and repair the aneurysm between clamps using interposition graft. Femoro-femoral bypass was used for distal perfusion.
2.2 Operative technique using sternotomy, cardio-pulmonary bypass and total circulatory arrest
Ten-patients were operated using this technique. Nine-patients were operated through midline sternotomy, while one was operated through transverse sternotomy centered at the 4th intercostal space in semi-right-lateral position. In two-patients, in midline sternotomy group, additional incision was made in the second left intercostal space for better access to descending thoracic aorta. The ascending aorta or femoral artery and bicaval cannulation initiated cardio-pulmonary bypass. Six cases were done with femoral arterial cannulation and the rest through aortic cannulation. Right superior pulmonary vein was vented. Thereafter, left innominate vein was taped and retracted cephalad. At 18° rectal temperature, the aorta was cross-clamped and after cardioplegic arrest and after withdrawing approximately 30% of circulating volume, circulation was terminated. The patient was positioned in steep Trendelenberg position. Pulmonary artery and arch of aorta was dissected and the left pericardial and pleural reflections were dissected away from the arch of aorta. The aneurysm was defined. The adhesion of the aneurysm sac to the lung was left undisturbed. The sac of the aneurysm was opened; the opening in aortic end was closed with a patch (patch aortoplasty) made from collagen coated Dacron graft (Hemashield®, Boston scientific, USA) using continuous 4–0 polypropylene sutures. The circulation was restarted with trickle flows, and the deairing of aorta was done through the loose throws of the suture. Thereafter, the sutures were tied and aortic cross clamp was released. In patients with fistulous connection to pulmonary artery, opening in pulmonary end was closed similarly during rewarming, under total cardio-pulmonary bypass. The patients were weaned off cardio-pulmonary bypass with inotropic support wherever necessary.
2.3 Follow-up
Letter was sent to all the survivors to attend our outpatient department for follow-up. The first and second author conducted the clinical history and physical examination. New-York Heart Association classification was determined on the basis of follow-up interview. Chest X-ray, both postero-anterior and lateral view, was evaluated. All cases underwent Trans-thoracic echocardiography examination by a single cardiologist (author 5). The pulmonary artery pressure was calculated by measuring right ventricular systolic pressure estimated by tricuspid regurgitation jet and adding right atrial mean pressure to it. Follow-up was completed in October 2003.
2.4 Statistical analysis
The statistical analysis was done using SPSS for Windows (version 11.0, Chicago Inc., USA). The continuous variables are expressed as mean±standard deviation.
3 Results
Prior to 1984, three cases underwent repair through left thoracotomy with femoro-femoral bypass without total circulatory arrest and all died on table due to rupture of aneurysm and exsanguination. Remaining ten-patients were operated through sternotomy using cardio-pulmonary bypass and total circulatory arrest. Thirty-day survival in this subgroup was 90% (9/10); one-patient died during surgery due to exsanguination. In this subgroup, mean cardio-pulmonary bypass time; mean aortic cross clamp time and mean total circulatory arrest time were 176.3±66.3, 51.3±20.8 and 36.6±19.6min, respectively. Mean intensive care unit stay was 5.2±3.1 days. Hospital stay ranged from 9 to 27 days. One-patient was re-explored for bleeding; this patient developed left hemiplegia; in this patient total circulatory arrest time was 75min. She recovered to monoparesis (grade III power) of left upper limb at the last follow-up. Four-patients had left vocal cord palsy pre-operatively, three of them recovered following surgery, and one had persistent left vocal cord palsy even at the time of last follow-up. Another patient was noticed to have left diaphragm palsy on follow-up. The follow up was complete in 8 (88.8%) patients and the mean follow up period was 9.6±5.3 years (range 1–17 years). One-patient was lost to follow-up after 3 years. All the remaining patients are in New-York Heart Association class I and showed good left and right ventricular function by echocardiography. The pulmonary artery pressure was normal in all the patients including the three patients who had elevated pressure.
4 Discussion
The occurrence of post-operative ductal aneurysm is very rare with less than 50 cases reported. Majority of the reports are case reports and no information exists in literature on the long-term outcome of the cases treated successfully [4–6]. Pubmed search revealed only three reported cases of post-operative ductal aneurysm in last 10 years [7,8] and we have seen only 13 cases of post-operative ductal aneurysm over a 27-year period. However, in one study the reported incidence of post-operative ductal aneurysm was as high as 13.8% after ligation of ductus [9].
Post-operative ductal aneurysm can present at variable time intervals after the first surgery. They occur due to ligature cutting through the tissues leading to formation of hematoma and false aneurysm formation [1]. Early presentation is often due to infection and it plays a major role in the development of post-operative ductal aneurysm with reported incidence of 58% [1,10]. Residual left to right shunt and infection are the important factors in its etiology; therefore, every effort should be made to prevent them. The measures may include meticulous surgical technique, prompt detection [11] and treatment of the residual left to right shunt, division and suturing of ductus, and antibiotic prophylaxis for infective endocarditis. It is rare after division and suturing (incidence 0.4%) and is usually a true aneurysm arising from the aortic diverticula [1]. It appears from our series and other reports [7,10] that this problem is more common after interruption of patent ductus arteriosus in older children or adolescents. Videoscopic ductus interruption in the first few months of life [12], as practiced in western countries could further decrease the incidence of this rare but dreaded complication. Incomplete occlusion [13,14] and infective endocarditis after patent ductus arteriosus interruption after interventional procedures are also potential causes for development of aneurysm. Giant aneurysm formation after interventional procedure for patent ductus arteriosus has already been reported and it was repaired through median sternotomy using cardio-pulmonary bypass [15].
Natural history is poor with almost 100% fatality in non-operated cases. Over a period, the aneurysm enlarges and get adherent to the overlying lung [1]. Death is due to rupture of the aneurysm or erosion of the nearby structures, lung, bronchus, trachea and esophagus [1]. Hemoptysis is an ominous sign of impending rupture and massive hemoptysis should raise the suspicion of aortobronchial fistula.
Pseudo aneurysms of the aortic isthmus are generally approached through left posterolateral thoracotomy and their resection involves various strategies for spinal cord protection. Perfusion of the lower body during aortic clamping is maintained by using partial left heart bypass, right atrial to femoral bypass, left femoro-femoral bypass or a passive shunt [16]. Successful treatment with left thoracotomy, proximal and distal aortic clamping and intrapericardial left pulmonary artery control, without cardio-pulmonary bypass, is also described. However, the authors caution its use due to concern for spinal cord perfusion [7]. Control of proximal and distal aorta is essential before dissection of the aneurysm and in most patients; it is repaired using interposition graft of synthetic material. The reported surgical mortality is very high with these techniques [1,2].
We had attempted to repair these aneurysms through left thoracotomy using femoro-femoral bypass. All the cases had extensive adhesions between the lung, chest wall and the aneurysm. In all the patients, the sac was very friable and its separation from the overlying lung led to its rupture and exsanguination. Moreover, majority of post-operative ductal aneurysm present with hemoptysis, signifying erosion to lung, therefore dissection for aortic clamping is likely to be difficult.
Left thoracotomy using femoro-femoral hypothermic bypass with circulatory arrest is increasingly used for the repair of pseudoaneurysms [17,18] hence it may be considered as an alternate management option. In large thoracic pseudoaneurysms, initiation of deep hypothermia (20°C) before thoracic incision may be helpful as this allows rapid institution of circulatory arrest in case the aneurysm is inadvertently entered [19]. However, this strategy may cause distention of the heart in post-operative ductal aneurysms with residual left to right shunt and could lead to myocardial dysfunction.
After the initial successful result in two cases using total circulatory arrest for repair of post-operative ductal aneurysm [3], this technique was used in further eight cases. The advantage of this approach is that the isolation of aneurysm can be done without dissection of overlying lung and its adhesions with the pleura. The approach was intra-pericardial. The limitations of this approach are inadequate access to left hilum and descending thoracic aorta. Hence by this approach replacement of the descending thoracic aorta by a prosthetic graft can be very difficult, in case the surgeon decides to replace it because of friable aorta. To circumvent this limitation, in the last case we performed the repair using transverse sternotomy, with the patient in semi-right-lateral position. With this approach the access to descending aorta was good allowing prosthetic graft replacement, if needed.
5 Conclusion
Repair of post-operative ductal aneurysm through left thoracotomy and femoro-femoral cardio-pulmonary bypass is difficult due to extreme fragility of aneurysm and because of reoperative difficulties. Repair through sternotomy using total circulatory arrest and minimal manipulation of aneurysm provides excellent operative and long-term outcome. The aorta surrounding the post-operative ductal aneurysm can be friable and repair requires the placement of secure sutures, which include tissue well away from the margins of the aortic defect. The access to descending aorta is limited in midsternotomy; however transverse sternotomy with the patient in semi-right-lateral position gives optimum access.
Aortogram in lateral view showing saccular aneurysm with recanalized ductus.
