Abstract: To summarize the characteristics and clinical experience of surgical approaches for aortic constriction (CoA) in infancy. Methods: We retrospectively analyzed 38 cases of CoA in infancy without intracardiac malformations admitted to the hospital from December 1998 to December 2008, including 7 cases of CoA alone and 26 cases of CoA with patent ductus arteriosus (PDA). 5 cases of CoA with PDA and aortic arch dysplasia. 31 of the 33 children with CoA alone and CoA with PDA underwent CoA segmental resection and aortic end-anastomosis. Among the 33 children with simple CoA and CoA combined with PDA, 31 had CoA segment resection and extensive end-to-end anastomosis of the lower edge of the aortic arch of the distal descending aorta. 2 had CoA left subclavian artery reversal patch widening. 5 had CoA combined with PDA and aortic arch dysplasia. RESULTS: Among the 38 cases in this group, one case died, with a mortality rate of 2.6%. The preoperative upper and lower extremity pressure difference was 30 mmHg to 58 mmHg. 1 case of postoperative bleeding was stopped by secondary opening of the chest, and 1 case of celiac disease occurred, which was cured after conservative treatment. There were no complications such as pseudoaneurysm, renal failure or lower extremity paraplegia. 33 cases were discharged from the hospital with ultrasound suggestive of aortic arch or descending aortic flow, and 4 cases suggested a pressure difference of 10-15 mmHg in the descending aorta. 29 cases were followed up for 6 months to 5 years, and echocardiography at the time of follow-up showed a pressure difference greater than 20 mmHg in the descending aorta in 3 cases, all of which were children who underwent end-to-end anastomosis. Conclusion: If there are symptoms of CoA in infancy, surgery should be performed urgently or on a deadline, and asymptomatic patients should also be operated as early as possible. The surgical anastomosis distance in infancy is short, easy to anastomose, and almost always end-to-end anastomosis can be performed. Postoperative complications are few and restenosis is less frequent. Keywords: aortic constriction; infant; cardiac surgery Surgical treatment of coarctation of the aorta in infants LUO Guo-hua, YAN Jun, WANG Qiang, Lv Xiao-dong, LI Shou-jun. Department of cardiac surgery, Fuwai hospital, Chinese academy of medical sciences & Peking union medical college, Beijing 100037, China Email: Yanjun1112@Yahoo. Abstract:Objective To summarize the surgical treatment of coarctation of the aorta (CoA) in infants. methods:From Dec. 1998 to Dec. 2008, 38 infants with CoA underwent coarctation. Of them 31 infants with or without patent ductus arteriosus (PDA) were performed end to end anastomosis of the aorta with removal of the coarctated segment and 2 infants with or without PDA were performed aortoplasty with left subclavain flap. 5 infants with CoA and Results There was one death, the operative mortality was 2.6 percent. The systolic pressure difference between lower limb and upper limb measured before operation was 30 to 58 mmHg.1 infant was There was no false aneurysm, no failure of renal function and no severe Doppler echocardiography revealed there was no gradient pressure in 33 infants and there was 10mmHg~15mmHg in 4 infants before discharge. Doppler echocardiography revealed there was 25mmHg, 30mmHg and 35mmHg gradient Conclusions The symptomatic infants with CoA should be corrected The symptomatic infants with CoA should be corrected emergently and the asymptomatic infants with CoA should be corrected as soon as the diagnosis is established. CoA in infants can be performed end to end anastomosis of the aorta with removal of the coarctated segment or performed extended end to side anastomosis of the descending aorta and the aortic arch Key words:Coarctation of the aorta;Infant;Cardiac surgery CoA is a stenosis of the aorta that occurs near the arterial ligament but is not confined to this region.(1) The prevalence is higher in Western countries and accounts for about The incidence is relatively low in Chinese, accounting for about 3% of congenital heart disease.(2,3) The detection rate of CoA in fatal congenital heart disease is second only to complete transposition of the aorta.(4) At present, surgical treatment of complex cardiac malformations such as complete transposition of the aorta in infants and children has been carried out successively in various places, but the simple CoA, which is a serious threat to infants’ lives, is rarely diagnosed and treated in China. The diagnosis and treatment of CoA alone, which is a serious threat to infants’ lives, has so far been rarely reported in China. From December 1998 to December 2008, 158 cases of infantile CoA were admitted to Fu Wai Hospital, among which 120 cases were combined with various intracardiac malformations. Since there is a great difference in the treatment of CoA with or without intracardiac malformations, only 38 cases without intracardiac malformations were studied in this paper and are reported as follows. Materials and methods 1.1 General data Among the 38 cases in this group, 28 were male and 10 were female. Among the 38 cases, there were 7 cases with CoA alone and 26 cases with CoA+PDA (PDA). 5 cases had CoA+PDA+aortic arch dysplasia. The CoA was divided into pre-catheter type and post-catheter type, and all cases in this group were pre-catheter type. All cases were clearly diagnosed by echocardiography, CT or aortography. 32 of the 38 cases were operated electively, and 6 cases were operated in an emergency. 1.2 Surgical methods Before the start of surgery, the upper and lower extremity dynamic pressure was measured by placing tubes in the right radial artery and lower extremity artery, respectively. Children with CoA alone and CoA+PDA were operated through a left lateral incision with a third or fourth intercostal approach. The PDA or ductus arteriosus ligament was cut, and the descending aorta, part of the aortic arch and the left subclavian artery near the narrowing were fully freed. In 31 cases, the descending aorta, part of the aortic arch and left subclavian artery were blocked, the narrowed aorta was resected, and end-to-end aortic anastomosis was performed with 5-0 or 6-0 absorbable or Prolene wires. In 3 of the 31 cases, the anastomosis was widened with autologous pericardium on the anterior wall of the anastomosis due to greater anastomotic tension. In another 2 children with early CoA+PDA, the narrowed aorta was widened with a left subclavian artery reversal patch. In 5 children with CoA+PDA+aortic arch dysplasia, an extensive end-to-end anastomosis was performed with the distal aorta and the lower edge of the aortic arch in a median opening. 1.3 Follow-up Follow-up through outpatient clinic. Results Among the 38 cases in this group, there was one death, which was due to pulmonary infection, with a mortality rate of 2.6%. The difference in pressure between the upper and lower extremities on invasive manometry after anesthesia was 30 mmHg~58 mmHg (36.3±21.5) mmHg. The results of invasive manometry immediately after surgery were higher blood pressure in the lower extremities than in the upper extremities in 22 cases; the blood pressure in the upper and lower extremities was basically equal in 13 cases; and the blood pressure in the lower extremities was lower than that in the upper extremities by 5-15 mmHg in 3 cases. The intraoperative blocking time of the descending aorta was 9 min~25 min (13.2±9.6). In one case, postoperative bleeding was stopped by second opening of the chest, and celiac disease occurred in one case, which was cured after conservative treatment. There were no complications such as pseudoaneurysm, renal failure or lower extremity paraplegia. 33 cases were discharged from the hospital with pre-discharge ultrasound indicating patency of the aortic arch or descending aorta, and 4 cases indicated a pressure difference of 10-15 mmHg in the descending aorta. 29 cases were followed up for 6 months to 5 years, with echocardiography showing pressure differences greater than 20 mmHg in 3 cases, 25 mmHg, 30 mmHg and 35 mmHg in the descending aorta. mmHg and 35 mmHg, all of which were children who underwent end-to-end anastomosis. Discussion 1. Diagnosis of CoA Clinical manifestations and signs of CoA in infancy are often atypical and easily missed. The more common clinical manifestations in this group are shortness of breath, pneumonia, and left heart failure. Some scholars believe that those with congenital congestive heart disease with pulmonary hypertension and heart failure, especially those with combined PDA, should be alert to the possibility of CoA. (5) Non-invasive determination of upper and lower extremity pressure difference is subject to more interfering factors and cannot reflect its real situation. Echocardiography combined with CT examination can provide information on the pressure difference across the stenosis, the site, extent, and morphology of narrowing. Aortography is the gold standard for the diagnosis of CoA. There is no uniform standard for determining the degree of aortic narrowing. Some scholars suggest that mild ischemic circumference is between 0.5 and 0.8 cm, and the ratio to ascending aortic diameter is between 30% and 45%; severe ischemic circumference is <0.5 cm, and the ratio to ascending aortic diameter is <30%.(4) Clinically, the aortic isthmus diameter of some children is only 1 mm, but the children's symptoms are not obvious, and CT examination suggests the presence of extensive thick collateral vessels. Therefore, we believe that from a clinical point of view, the severity of stenosis is better reflected by the level of blood pressure in the lower extremities or the size of the pressure difference between the upper and lower extremities, and aortic arch dysplasia is sometimes difficult to define. It has been suggested that aortic arch dysplasia can be considered when the number of millimeters of transverse arch diameter (D) < the value of the child's kilogram weight (w) plus 1, i.e., D < W + 1. A more refined method is the assessment of the segments of the aortic arch. The aortic arch is considered dysplastic if the length of each segment does not exceed 5 mm; compared with the lumen diameter of the ascending aorta, the ascending segment should reach 60%, the horizontal segment should reach 50%, and the isthmus should reach 40%, and if the above criteria are not met, the segment is dysplastic.(6) The latter criterion is mostly used in our group for aortic arch dysplasia and repair. 2, the choice of the timing of CoA surgery Infantile CoA, the occurrence of left heart failure and progressive severe hypoperfusion, should be treated with timely surgery under active medical treatment. In our group, 32 cases were elective surgery and 6 cases were emergency surgery. In the past, it was thought that surgery could be delayed until 4 to 6 years of age except in asymptomatic patients to achieve the lowest incidence of recontraction. However, one study found that the incidence of cardiovascular complications and late postoperative hypertension after CoA in infancy were the lowest, so this age was considered to be the best time for CoA correction (7) and Pearl et al. suggested that treatment of CoA in infancy was not a significant correlate of recrudescence by analyzing the outcome of 120 CoA patients (8). 3. Surgical approach for CoA in infancy Most scholars currently believe that resection of the narrowed segment with end-to-end anastomosis is the most ideal approach, which can significantly reduce the incidence of recontraction and reoperation rate (9,10). In our group of children without combined aortic arch dysplasia, narrowed segment resection with end-to-end anastomosis was used except for two children with early left subclavian artery who had a widened narrowed aorta using a left subclavian artery reversal patch. For longer segments of CoA, as long as the descending aorta near the narrowing is adequately free, part of the aortic arch and the left subclavian artery can also be resected with end-to-end anastomosis. If the anastomotic tension is large, the anastomosis can be widened with autologous pericardium at the anterior wall of the anastomosis. In three cases, the anastomosis was widened with an autologous pericardial anastomosis in the anterior wall of the anastomosis due to the large tension of the anastomosis, and satisfactory results were achieved. In children with aortic arch dysplasia, the distal descending aorta distal to the stenosis can be extensively anastomosed with the lower edge of the aortic arch. A median opening can better reveal the dysplastic aortic arch. 4. Prevention and control of complications of CoA surgery in infancy The most dangerous complications of aortic narrowing surgery are paraplegia and acute renal failure. The focus of avoiding complications is on prevention. Intraoperative coiling of the intercostal arteries and collateral vessels near the narrowing with polyester wire can both well reveal the operative field and reduce blood loss, and maintain high lower limb blood pressure during aortic block. Shortening the duration of aortic block is an important tool for preemptive paraplegia and acute renal failure. The CoA procedure in infancy is simple and the average time to block the descending aorta in our group is 13 min. In addition, timely correction of acidosis plays an important role in avoiding ischemic damage to the spinal cord and kidneys (11,12,13). References 1. Therrien J, W arnes C,Daliento I, et a1. Canadian Cardiovascular Society Consensus Conference 2001 update: Recommendations for the management Canadian Cardiovascular Society Consensus Conference 2001 update: Recommendations for the management of adults with congenital heart disease part Ⅲ, Can J Cardiol, 2001, 17(11):1135-1158. 2. Ding WX, Su ZZ, eds. Pediatric Cardiac Surgery Jinan: Shandong Science and Technology Press, 2000,261-269. 3. Hoffman JI , Kaplan S. The incidence of congenital heart disease. , Kaplan S. The incidence of congenital heart disease. J Am Coll Cardiol, 2002, 39(12):1890-1900. 4. Zou JZ, Cai LL, Wu SA, et al. Pathological basis of clinical management of infantile aortic constriction Chinese Journal of Thoracic and Cardiovascular Surgery, 2004, 20(6):344-347. 5. Kwong W.Y., Wang W.S. Analysis of 6 cases of neonatal aortic constriction death Journal of rare diseases, 2003, 10(3):25-266 Yang S.Y. Pediatric cardiology, 2nd ed. 2001, 222. 7. Li SJ, Wang YL, Liu TL Treatment of aortic constriction Journal of Clinical Pediatrics, 2007, 25(7):609-612. 8. Peal JM, Manning PB, Franklin C. Risk of recoarctation should not be a deciding factor Am J Cardiol, 2004,63(2):236-239. 9. Brouwer RM, Cromn-Dijkhuis AH, Erasmus ME, et a1. Decision making for the surgical management of aortic coarctation. surgical management of aortic coarctation associated with ventricular septal defect. j Thorac Cardiovasc Surg, 1996, 111(1):168-175. 10. Backer CL, Mavroudis C, Zias EA, et a1. Repair of coarctation with resection and extended end to end anastomosis. An Thorac Surg, 1998, 66: l365-l370. 11. Fujisawa Y, Morishita K, Fukada J, et a1. Strategy for adult aortic coarctation complicated by coronary artery disease. Asian Cardiovasc Thorac Ann, 2007, 15(3): 41 -12. Yamada A, Morishita K, Kawaharada N, et a1. A safe strategy for surgical repair of coarctation of the aorta in an adult. J Thorac Cardiovasc Surg, 2003,126(2):597-598. 13.Chessa M, Carrozza M, Butera G, et a1.Results and mid- long term follow up of stent implantation for native an d recurrent coarctation of the aorta.Eur Heart J, 2005, 26(24):2728-2732.