Etiology and management of chylothorax following pediatric heart surgery
Etiology and Management of Chylothorax Following Pediatric Heart Surgery Michael Milonakis, M.D., Andrew C. Chatzis, M.D., Nikolaos M. Giannopoulos, M.D., Constantinos Contrafouris, M.D., Dimitrios Bobos, M.D., George V. Kirvassilis, M.D., and George E. Sarris, M.D. Department of Pediatric and Congenital Cardiac Surgery, Onassis Cardiac Surgery Center,Athens, GreeceABSTRACT Background: Chylothorax after congenital heart surgery (CHD) is a potentially challenging com- plication. The purpose of this study was to review our experience with the management of chylothorax following congenital heart surgery. Methods: Between September 1997 and August 2006, of 1341 pediatric patients undergoing correction of congenital heart disease in our institution, 18 (1.3%) developed chylotho- rax postoperatively. Surgical procedures included tetralogy of Fallot repair in 10 patients, ventricular septal defect closure (one), atrial septal defect with pulmonary stenosis repair (one), Fontan procedure (three), coarctation of the aorta repair (one), aortopulmonary shunt (one), and ligation of patent ductus arteriosus in one patient. All patients followed a therapeutic protocol including complete drainage of chyle collection and controlled nutrition. Somatostatin was used adjunctively in six (33.3%) patients. Surgical intervention was reserved for persistent lymph leak despite maximal therapy. Following resolution of chylothorax, a medium-chain triglyceride diet was implemented for six weeks. Results: There were no deaths. Fifteen patients (83.3%) responded to conservative therapy. Lymph leak ranged from 2.5 to 14.7 mL/kg per day for 8 to 42 days. Three patients with persistent drainage required thoracotomy with pleurodesis to achieve resolution, in two of which previously attempted chemical pleurodesis with doxycycline proved ineffective. Duration of lymph leak in this subgroup ranged from 15 to 47 days with 5.1 to 7.4 mL/kg per day out- put. Conclusions: Postoperative chylothorax is an infrequent complication of surgery for congenital heart disease and can occur even after median sternotomy in the absence of pathologically elevated venous pressure or Fontan circulation. Although hospitalization can be prolonged, conservative therapy is effective in most cases, while surgical pleurodesis proved successful in the refractory cases. doi: 10.1111/j.1540- 8191.2008.00781.x (J Card Surg 2009;24:369-373) Postoperative chylothorax in childhood is a poten-nine males and nine females, aged 5 to 68 (mediantially serious complication of any thoracic surgical19.5) months old and with body weight 6 to 18.7 (me-procedure and its management represents a seriousdian 9.2) kg, developed chylothorax 1 to 15 days post-challenge. In particular, chylothorax occurring after pe-operatively. Surgical procedures preceding the occur-diatric congenital heart surgery is an uncommon com-rence of lymph leak included tetralogy of Fallot (TOF)plication, occurring in 0.6% to 2% in reported series.1,2repair in 10 patients, ventricular septal defect (VSD)The intent of our study was to explore the etiology andclosure (one), atrial septal defect (ASD) closure withpresent our experience with the management of thispulmonary stenosis (PS) correction (one), Fontan pro-cedure (three), coarctation of aorta (CoA) repair (one),patent ductus arteriosus (PDA) ligation (one), and place-MATERIALS AND METHODS ment of a central aortopulmonary (A-P) shunt in a pa-tient with complex CHD (one). Surgical access hadThe hospital records of all children with a postop-been achieved via median sternotomy in 15 and lefterative chylothorax following congenital heart surgerythoracotomy in three patients. Patient characteristicsat our institution between September 1997 and Au-and procedures are listed in Table 1.gust 2006 were reviewed. During this period, 1341Chylothorax was suspected when persistent chestpediatric patients underwent surgery for congenitaltube drainage occurred or a pleural effusion developedheart disease (CHD). Of these, 18 patients (1.35%),with the characteristic milky fluid. Microscopic andbiochemical analyses of this fluid revealing a triglyc-eride (TG) level > 1.2 mmol/L and total cell countAddress for correspondence: Michael Milonakis, M.D., 356 Sygrou> 1000/μL, predominantly lymphocytes establishedAve, 17674 Kallithea, Athens, Greece. Fax: +30210-9493870; e-mail:firstname.lastname@example.orgPatient Characteristics and Procedures Duration Diagnosis/ Patients (Month) Operation (mL/kg/Day) Somatostatin Doxycyclin Surgery Comments All patients were treated conservatively, initially,the course of the thoracic duct. The etiology of lymphwith complete pleural drainage of the chyle collectionleak in these patients is unclear but may involve in-and either enteral low-fat diet or, in most cases, to-jury to small lymphatic vessels around the ascendingtal parenteral nutrition (TPN). A somatostatin analogueaorta, the superior vena cava, or the pulmonary arterywas used adjunctively in six patients (33.3%). At-trunk and its branches, which may require extensivetempted chemical pleurodesis with doxycycline viadissection for cannulation or repair. Variations in lym-chest tube was unsuccessful in two patients. Surgicalphatic pathways and the presence of accessory or mi-intervention was reserved for persistent lymph leak de-nor lymphatic channels in the mediastinum may renderspite maximum medical treatment and was necessarythem vulnerable to inadvertent trauma during thesein three patients. All patients continued on medium-procedures, resulting in chylous effusion without in-chain triglyceride (MCT) diet for a total of six weeksterference of the main thoracic duct. Chylopericardiumfollowing resolution of chylothorax and on low-fat diethas been reported as a rare complication after opera-tions for congenital heart disease.3 Isolated chyloperi-cardium is difficult to diagnose and may be mistaken forpostpericardiotomy syndrome. This raises the questionwhether the pleural effusions seen in our sternotomyThere were no deaths. Fifteen patients (83.3%) re-cases are in fact pericardial collections draining throughsponded to conservative therapy. The median durationan opening in the pleura in one of the hemithoraces andof lymph leak in these patients was 16 days (range 8 topresenting as chylothoraces. It should be mentioned42), and the median lymph leak 5.6 (range 2.5 to 14.7)that we routinely open both pleurae (drained separatelymL/kg per day. In two out of three patents with per-to prevent postoperatively fluid collection). It is of in-sistent drainage, chemical pleurodesis with doxycyclinterest that in two of our patients, the presentation ofvia chest tube proved ineffective. The median durationchylothorax in the right hemithorax coincided with theof lymph leak in this medically refractory subgroup wasdevelopment of a mild pericardial effusion.24 (range 24 to 47) days with median output 7.4 (rangeChylothorax can also occur after obstruction in the5 to 8.7) mL/kg per day. These patients underwent tho-superior vena cava without anatomic injury of lymphracotomy, lymphatic ligation, and abrasion pleurodesischannels. Blalock et al. proved experimentally that oc-resulting in postoperative resolution of chylothorax.clusion of the superior vena cava (SVC) can producechylothorax.4,5 Therefore, certain cardiovascular pro-cedures like the Fontan operation are more prone toCONCLUSION this complication due to the expected increase in SVCInjury to the main thoracic duct or its branches ispressure. However, no sign of increased central ve-possible after virtually any procedure performed nearnous pressure was noted in our group of patients, andits route, typically during aortic procedures performedonly three of the 40 patients (7.5%) who underwentin the left hemithorax. However, most of our patientsa Fontan procedure during the same period developed(83.3%) who developed chylothorax had undergonepostoperative chylothorax, this complication occurringa sternotomy, and surgical manipulation remote fromdespite a low Fontan pressure (∼12 mmHg).
Continue MCT diet for 6 weeks Remove drain when output <1ml/kg/day
Figure 1. Protocol for postoperative chylothorax treatment. Lymphatic dysplasia with spontaneous chylothoraxanalyses of the pleural effusion should show triglyc-is also a feature of Noonan and Turner syndromes.6,7erides > 1.2 mmol/L and cell count > 1000 cell/μL withOne of our patients who developed chylothorax aftera predominance of lymphocytes.9,10 Because dietaryASD closure had Noonan’s syndrome.fat in neonates and infants either consists mainly ofThe morbidity of chylothorax is potentially severe, astriglycerides, or is metabolized to them during diges-large losses of fluids, proteins, lipids, and white bloodtion, the presence of cholesterol cannot be expected.cells can cause dehydration, nutritional deficiency, andTherefore, it is best to measure triglyceride levels in aimmunologic dysfunction. Nonetheless, intrapleural in-fections are rare, possibly due to the bacteriostatic na-Upon diagnosis, aggressive medical therapy shouldture of the chylous fluid.8 Accurate diagnosis and earlybe commenced immediately.12-14 Our therapeutic pro-treatment are important for achieving a favorable out-tocol (Fig. 1) involves an initial approach with completecome and, therefore, the development of a pleural effu-evacuation of pleural effusion to obtain good lung ex-sion after a thoracic procedure should always raise thepansion. In addition, no or low-fat enteral diet is estab-suspicion of possible chylothorax. Diagnosis is basedlished. It has been shown that long-chain fatty acids ofon examination of the effusion. Chyle is a lymphatic12 or more carbon atoms undergo a second esterifi-fluid enriched with fat absorbed by intestinal cells andcation and enter the lymph as chylomicrons, whereastransported via the thoracic duct into the circulation.medium-chain fatty acids pass directly into the por-The fluid has a milky appearance when chylomicronstal system coupled to albumin.15 This has led to theare present, while during starvation it appears clearadoption of a medium-chain triglyceride diet as nutri-with a light yellow tint. Microscopic and biochemicaltional support for patients with chylothorax. When oraldiet is not successful, oral intake is forbidden and totalanatomy, often lead to failure of this approach, result-parenteral nutrition (TPN) infusion instituted. This con-ing in continuous chylous effusion with the associatedservative approach was effective in 15 (83.3%) of ourmorbidity.2 Our preferred surgical strategy is to per-patients, although a lengthy hospitalization was neces-form a thoracotomy on the affected side aiming tosary. The time limit for conservative treatment is threeidentify and control the specific lymphatics involved,to four weeks as most of our patients responded fa-if possible with the aid of preoperative cream adminis-vorably to medical therapy within that time frame. Con-tration. In addition, abrasion pleurodesis completes theservative treatment should not be thought to be freeprocedure. This approach was successful in the threeof complications. Parenteral nutrition itself may engen-patients, one of who had a lymphatic leak associatedder several problems related to infection, thrombosis,with an operation around the descending thoracic aortaor cholestasis.16 However, we have not encounteredsuch problems in our small series of patients.Our data confirm that postoperative chylothorax fol-There is scarce clinical evidence that somatostatinlowing surgery for congenital heart surgery is rare andmay be helpful in affecting the rate and amount of tho-in some instances may be connected to chyloperi-racic chyle leak.17 Somatostatin reduces gastric, pan-cardium. Nonoperative management can be success-creatic, and intestinal secretion.18-20 The inhibition offul in the majority of cases.23 Somatostatin may playserotonin and other gastrointestinal peptides also ap-an adjunctive role in some patients, while doxycyclinepears to reduce intestinal absorption and decrease hep-chemical pleurodesis seems entirely ineffective. Sur-atic venous pressure gradient and splachnic blood flow.gical intervention can be reserved for the minority ofThis influence on the hemodynamics of splachnic circu-patients who fail to respond to medical treatment and itlation (increased splachnic arteriolar resistance) and in-is successful. Overall appropriate therapy of this com-testinal motility (decreased gastrointestinal blood flow)plication may be lengthy but can prevent significantmay be reflected in a reduction of chyle output.21 Insix of our patients (33.3%), a somatostatin analoguewas added as an adjunct to the initial conservativeREFERENCES treatment and was administered as a continuous in-1. Le Coultre C, Oberhansli I, et al: Postoperative chylotho-travenous infusion in gradually increasing dosage for arax in children: Differences between vascular and trau-maximum period of two weeks. In our limited experi-matic origin. J Pediatr Surg 1991;26:519-523.ence, this appeared to be the maximum period of time2. 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