R early primary complete repair in many patients with

Modified Blalock-Taussig Shunts: Results in Infants Less Than Months of Age Daniel Tamisier, MD, Pascal R. Vouhe, MD, Francoise Vernant, MD, Francine Leca, MD, Christian Massot, PhD, and Jean-Yves Neveux, MD Service de Chirurgie Thoracique et Cardiovasculaire, HBpital Laennec, Paris, France The optimal procedure for ing palliation in cyanotic infants remains to be determined. Sixty-two infants less than months of age underwent modified Blalock-Taussig s. Their age range at operation was 1 to days (mean, 1 f days). Shunts were constructed using -mm polytetrafluoroethylene tubes in patients and -mm polytetrafluoroethylene grafts in patients. There were 1 early deaths (1%; CL, 1% to %) of which three deaths (%; confidence limits, % to %) were related. The survivors were followed up from to months (mean, f 1. months). Shunt failure (occlusion, inadequate palliation) occurred in pa- tients. The overall probability rate of adequate function was % f % at years. Univariate and multivariate analyses showed that the size of the graft was a risk factor of failure. Severe distortion of the pulmonary arterial branch was noted in 1 patients. The inferences are: (1) modified Blalock-Taussig s provide satisfactory early palliation but late failure is frequent; () similar results should be obtained with other ing procedures; and () the optimal procedure should be selected for each cyanotic infant on an individual basis. (Ann Thorac Surg 10;:-01) ecent advances in pediatric cardiac surgery allow R early primary complete repair in many patients with congenital heart malformations and decreased pulmonary blood flow. However, a substantial number of patients still require a palliative procedure to increase pulmonary blood flow during infancy. The Potts and Waterston s have been strongly advocated and then abandoned in most centers. The classic Blalock-Taussig remains the of choice in children, but it is questioned in infants because of a high rate of inadequate palliation. The modified Blalock- Taussig (MBTS) using a polytetrafluoroethylene conduit was first designed for patients in whom a classic Blalock-Taussig could not be carried out. Satisfactory results were obtained, and many centers considered the MBTS the procedure of choice, particularly in infants. The MBTS offers several advantages: (1) high early patency rate, () regulation of the flow by the size of the systemic artery, () preservation of the subclavian artery, and () ease of the surgical procedure. Early results with the MBTS have been widely reported. However, reports on long-term results, especially in infants, remain scarce. Our experience with the MBTS in infants less than months of age is reported in an attempt to identify the predicting factors of adequate function. Material and Methods Patient Population Sixty-two infants (age, < months) underwent MBTS procedures between January 1, 1, and December 1, Accepted for publication Jan, 10. Address reprint requests to Dr Vouhe, HBpital Laennec,, rue de Shres, 0 Paris Cedex 0, France. 1. The mean age (t standard deviation) was 1 t days (range, 1 to days). Fifty-six patients (%) were neonates (<1 month of age); (%) were newborns (<1 week of age). The mean weight (t standard deviation) was. t 0. kg (range,.1 to. kg). The diagnoses were grouped into four categories (Table 1): group 1, tetralogy complex (1 patients); group, transposition complex (1 1 patients); group, univentricular heart (1 patients); and group, pulmonary atresia or critical stenosis with intact ventricular septum ( patients). The pulmonary artery was atretic in 0 patients (.%). The size of the pulmonary arterial branch, as assessed at operation, was mm in patients, mm in 1 patients, mm in 1 patients, mm in 1 patients, mm in 1 patients, and mm in patients. Surgical Technique The s were constructed by interposing a conduit between the subclavian artery and the ipsilateral pulmonary arterial branch. Systemic and pulmonary anastomoses were done end to side using a running polypropylene suture. Sixty-three thin-walled polytetrafluoroethylene tubes (Gore-Tex, William Gore, Inc, Flagstaff, AZ) ( mm in s, mm in s) were used. Fifty-six s were performed on the right side and seven, on the left side. The procedure was done through a standard lateral thoracotomy except in 1 infants with pulmonary atresia and intact ventricular septum in whom concomitant placement of a right-sided MBTS and closed pulmonary valvotomy were performed through a median sternotomy. Heparin was not administered before or during operation but was given at a low dosage (1 mg/kg/day) during the first three to five postoperative days and then replaced by long-term aspirin therapy. 0 10 by The Society of Thoracic Surgeons 000-/0/$.0

TAMISIER ET AL Ann Thorac Surg 10;:-01 Table 1. Diagnoses of lntracardiac Anomalies No. of Patients With With Pulmonary Pulmonary Stenosis Atresia Total Tetralogy complex 11 1 Transposition complex 11 Univentricular heart (includes 1 tricuspid atresia) Pulmonary atresia or critical stenosis and intact ventricular septum Shunt Patency, Adequacy of Palliation, and Follow-up Shunt patency was determined using a combination of clinical findings, two-dimensional Doppler echocardiography, and cardiac catheterization. Shunt failure was defined by one of the following: occlusion, reappearance of cyanosis with progressive decrease in oxygen tension, or need for a second or complete repair (nonelective). Length of time from anastomosis to failure was noted. Follow-up data (100% complete) were obtained during the -month interval from May to July 1. Children not followed up at this institution were contacted through referring physicians. Pulmona y Artey Distortion Postoperative angiography was available in patients. Cardiac angiography was performed for failure (1 patients) or for scheduled elective operation (1 patients). Pulmonary artery distortion was defined as a stenosis severe enough to require correction at the time of definitive intracardiac repair. Statistical Analysis Continuous data are presented as means f 1 standard deviation and crude ratios with 0% confidence limits (CL). Univariate and multivariate analyses were used to evaluate the adequacy of palliation and to assess the importance of the following risk factors: age, weight, presence of pulmonary atresia, diagnostic groups, size of the pulmonary arterial branch, and size of graft. In univariate analysis, product-limit methods (Kaplan and Meier) and log-rank test (BMDPlL)[l] for comparison of survival curves were used to evaluate the duration of adequate function. The multivariate analysis used the stepwise Cox regression model (BMDPL)[l]. Statistical significance was established at p = 0.0. Results Early Mortality (Within 0 Days) Two intraoperative and 11 postoperative deaths yielded an overall early mortality rate of 1% (CL, 1% to %). All deaths but two occurred in neonates. Three early deaths (%; CL, % to %) were related. Two s were patent but inadequate; the patients died despite an urgent second procedure. One infant had early heart failure, probably related to excessive pulmonary blood flow, and died despite reduction of the. The other causes of death were: low cardiac output ( patients), sepsis (), sudden death (), and surgical mismanagement (1 patient). Early Shunt Failure (Within 0 Days) Early failure occurred in patients (%; CL, % to 1%) (Table ). Two s were occluded, and three were patent but inadequate. Four infants underwent a second (three central s and one contralateral MBTS); patients died during reoperation. One patient underwent a successful intracardiac repair. Late Results Twenty-two failures occurred during follow-up. Eleven patients underwent a second procedure, and had nonelective intracardiac repair. One child, who lived in a distant foreign country, died before reoperation could be performed. Two patients with pulmonary atresia and intact ventricular septum who had undergone concomitant placement of an MBTS and pulmonary valvotomy had thrombosis but did not require reoperation owing to an adequate valvotomy. The overall adequate palliation rates estimated by product limit methods were %? % at 1 year, % & % at years, and 1%? % at years (Fig 1). Univariate and multivariate analyses showed that the size of graft was a significant risk factor of failure (Tables, ). The probability rate of adequate palliation was significantly lower with a -mm polytetrafluoroethylene conduit (Fig ). Distortion of the Pulmonary Arterial Branches Severe distortion of the pulmonary arterial branch was observed in 1 patients (Table ). Among 1 MBTSs functioning more than months, 10 of the failed s showed distortion of the pulmonary artery at the site of the anastomosis. Table. Early Shunt Failures Graft Intracardiac Age Size Subsequent Anomaly (days) (mm) Operation Result Critical pulmonary Complete Survived stenosis and repair intact ventricular septum Tetralogy with PA Contralateral Survived Central Died 1 Central Survived Tetralogy with PA Central Died and hypoplasia of pulmonary arterial tree PA = pulmonary atresia.

Ann Thorac Surg 10;-01 TAMISIER ET AL 100-0 Fig 1. Actuarial probability of adequate function for all s. 0 0 0 0 0 0 10 W-Q% I 1 W-BZ plus or minus Standard Error - **-number of cases at risk () 1 1 0 MONTHS AFTER OPERATION Comment Shunting procedures are indicated for critically ill cyanotic newborns or infants with complex malformations that are not amenable to primary complete repair []. The ideal should (1) provide adequate pulmonary blood flow, () allow flow to increase with growth, () be reliable in its early and late flow characteristics, () provide bilateral pulmonary arterial flow, () avoid distortion of the pulmonary arterial anatomy, and () be simple to construct and to take down []. There is wide agreement Table. Risk Factors of Shunt Failure (Univariate Analysis) Risk Factor Age 0 days >0 days Weight kg > kg Pulmonary atresia Yes No Diagnosis group 1 Size of pulmonary artery mm > mm Size of graft mm mm Number Observed of Shunts Failures p Value 0. 0. 1 1 0.0 0 1 0. 1 11 1 0 1 11 0. 0.00 to consider the MBTS [] the procedure of choice [,, 1. Our experience confirms that the MBTS provides satisfactory early palliation: the early occlusion rate is low, excessive pulmonary blood flow is extremely rare, complications are infrequent (serous leakage and seroma formation have been reported but are unusual), and take-down of the at the time of complete repair is easy, particularly when a right-sided (in situs solitus) MBTS has been used. A high early mortality rate (1%) was noted. This may be explained by a high incidence of neonates with severe congenital anomalies. Among the 1 early deaths, 11 occurred in infants less than 1 month of age, and eight deaths occurred in patients with pulmonary atresia and intact ventricular septum or with univentricular heart. Only three deaths were related. Very young age and severity of the cardiac malformation have been clearly determined as major risk factors for early deaths in large series of ing procedures [, -10]. As suggested by Bove and associates [], we used strict Table. Risk Factors of Shunt Failure (Univariate and Multivariate Analyses) Multivariate Univariate Analysis Analysis (Stepwise (log-rank cox Test) Regression) Risk Factor p Value p Value Age 0. 0.1 Weight 0. 0. Pulmonary atresia 0.0 0.11 Diagnosis group 0. 0. Size of pulmonary artery 0. 0.0 Size of graft 0.00 0.01

~~~ 00 TAMISIER ET AL Ann Thorac Surg 10;:-01 Fig. Actuarial probability of adequate function according to the size of polytetrafluoroethylene (PTFE) graft. o 1 mm PTFE '1?I t 0 0 +/-1Z I 10 * plus or minus Standard Error ** number of cases at risk MONTHS AFTER OPERATION criteria to assess the adequacy of late palliation. Only % of all s were functioning adequately years after operation. The probability of adequate palliation was significantly higher (% at years) when a -mm polytetrafluoroethylene conduit was used. The relatively disappointing palliation afforded by -mm s have been reported and justified the routine use of -mm conduits. However, it is sometimes technically impossible to use a -mm graft, especially in tiny neonates with very small systemic and pulmonary vessels. There is disagreement in the literature on the incidence of pulmonary artery distortion; rates ranging from 0% to % have been reported [, 1. In the present series, the Table. Distortion of the Pulmonary Arterial Branch Size of Pulmonary Time of Ageat Arterial Shunt Intracardiac Shunt Branch Failure Graft Size Anomaly (days) (mm) (mo) (mm) PA with VSD PA with VSD UVH with PA TGA with PS TGA with PS 0 1 1 1 1 1 IVS = intact ventricular septum; PA = pulmonary atresia; PS = pulmonary stenosis; FTFE = polytetrafluoroethylene; TGA = transposition of the great arteries; UVH = univentricular heart; VSD = ventricular septa1 defect. exact incidence of pulmonary arterial distortion is difficult to determine in the absence of systematic postoperative angiographic studies. However, this incidence is probably relatively high. Among the s that failed (and therefore were studied angiographically) 0% showed a distortion of the pulmonary arterial branch. The stenosis may occur at the anastomosis site itself and be related to a discrepancy between the size of the pulmonary arterial branch and that of the rigid prosthetic conduit. The stenosis may also include the area before or after the anastomotic site (Fig ) and be caused by clamp injury or failure to grow because of fibrosis of the surrounding tissue. Nevertheless, the occurrence of a severe stenosis is a -related complication that may markedly increase the risk of the subsequent complete repair. Fig. Severe stenosis of the pulmonary arterial branch after a rightsided modified Blalock-Taussig (see text).

Ann Thorac Surg 10;-01 TAMISIER ET AL 01 In conclusion, the optimal ing procedure in infants remains to be determined. Improvements in results could be sought at least in two ways. (1) Polytetrafluoroethylene is probably a less-than-optimal material. The low rate of late adequate palliation may be due to excessive pseudointimal formation, especially with -mm conduits [, 1. The high incidence of pulmonary arterial distortion may be related at least in part to the use of a thick and rigid graft anastomosed to a small, thin vessel. To reduce these drawbacks, we are using a new biological vascular graft. The early results are encouraging, but the late results remain to be evaluated [ll].() An individualized approach should be used according to the type of the cardiac malformation, the anatomy of the systemic and pulmonary vessels, and the planned surgical management. Recent reports have shown that both classic Blalock- Taussig s [lo, 11 and central s [1, 11 may provide satisfactory palliation. When a long-term palliation is needed, a classic Blalock-Taussig (if the size and the length of the subclavian artery are suitable) or a -mm MBTS should be used. If complete repair of the malformation can be planned for the patient s first year of life, a small-diameter MBTS provides adequate results. The preservation of the pulmonary artery anatomy may be of critical importance (major hypoplasia of the pulmonary arteries, planned Fontan-type repair); a central is then probably a good alternative. We express our appreciation to Corinne Pasquet for secretarial assistance. References 1. BMDP statistical software manual. Berkeley, CA: University of California Press, 1.. Moulton AL, Brenner JL, Ringel R, et al. Classic versus modified Blalock-Taussig s in neonates and infants. Circulation 1;(Suppl ):-.. Lamberti JJ, Carlisle J, Waldman JD, et al. Systemicpulmonary s in infants and children. Early and late results. J Thorac Cardovasc Surg 1;:-1.. De Leva1 MR, McKay R, Jones M, Stark J, Macartney FJ. Modified Blalock-Taussig : use of subclavian artery orifice as flow regulator in prosthetic systemic-pulmonary artery s. J Thorac Cardiovasc Surg 11;1:11-.. Ilbawi MN, Grieco J, DeLeon SY, et al. Modified Blalock- Taussig in newborn infants. J Thorac Cardiovasc Surg 1;:0-.. Woolf PK, Stephenson LW, Meijboom E, et al. A comparison of Blalock-Taussig, Waterston, and polytetrafluoroethylene s in children less than two weeks of age. Ann Thorac Surg 1;:-0.. Bove EL, Kohman L, Sereika S, et al. The modified Blalock- Taussig : analysis of adequacy and duration of palliation. Circulation 1;(Suppl ):1-.. Ullom RL, Sade RM, Crawford FA, Ross BA, Spinale F. The Blalock-Taussig in infants: standard versus modified. Ann Thorac Surg 1;:-.. Arciniegas E, Farooki ZQ, Hakimi M, Perry BL, Green EW. Classic ing operations for congenital cyanotic heart defects. J Thorac Cardiovasc Surg 1;:%. 10. Stewart S, Alexson C, Manning J. Long-term palliation with the classic Blalock-Taussig. J Thorac Cardovasc Surg 1;:11-1. 11. Vouhe PR, Caliani J, Tamisier D, et al. Systemic-pulmonary s using a preserved bovine internal mammary artery. In: Proceedings of Bioflow small diameter graft symposium- Garmisch 1. St. Paul: Biovascular Inc, 1:MO. 1. Guyton RA, Owens JE, Waumett JD, Dooley KJ, Hatcher CR, Williams WH. The Blalock-Taussig : low risk, effective palliation, and pulmonary artery growth. J Thorac Cardiovasc Surg 1;:1-. 1. Amato JJ, Marbey ML, Bush C, et al. Systemic-pulmonary polytetrafluoroethylene s in palliative operations for congenital disease. Revival of the central. J Thorac Cardiovasc Surg 1;:-. 1. Barragry TP, Ring WS, Blatchford JW, Foker JE. Central aorta-pulmonary artery s in neonates with complex cyanotic congenital heart disease. J Thorac Cardiovasc Surg 1;:-.