Does the modified Blalock-Taussig shunt cause growth of the contralateral pulmonary artery?

BACKGROUND: Although some pediatric cardiology departments have a policy of adopting primary correction of tetralogy of Fallot in all symptomatic infants, we and others still palliate neonates and infants. Effective palliation should ameliorate symptoms and allow growth of the pulmonary arteries. Although studies on the growth of the ipsilateral and contralateral pulmonary arteries after a classic Blalock-Taussig shunt have been reported, pulmonary artery growth after a modified Blalock-Taussig shunt has not been studied as thoroughly. Therefore, we examined whether there is equal growth of the contralateral pulmonary artery after a modified Blalock-Taussig shunt. METHODS: We retrospectively analyzed the records of 140 patients with symptomatic tetralogy of Fallot who had a modified Blalock-Taussig shunt between October 1985 and October 1995. The median age at the time of the Blalock-Taussig shunt was 1.6 months. All patients had corrective procedures at a median age of 1.7 years. Cineangiography was done before the corrective procedure. From the angiograms the diameter of the right and left pulmonary arteries before their first lobar branches and the diameter of the descending thoracic aorta at the level of the diaphragm were measured. For each patient the ratios of right pulmonary artery to descending thoracic aorta and left pulmonary artery to descending thoracic aorta were determined and compared using Student's t test. RESULTS: Of the 140 patients, 114 had a left-sided Blalock-Taussig shunt, 20 had a right-sided shunt, and 6 patients had bilateral shunts. The mean right pulmonary artery to descending thoracic aorta ratio was 1.10 and the mean left pulmonary artery to descending thoracic aorta ratio was 0.98. This difference was not significant. CONCLUSION: We showed equal growth of the right and left pulmonary arteries with no distortion after a modified Blalock-Taussig shunt. If palliation is considered, the modified Blalock-Taussig shunt remains our choice.     

Surgical strategy for pulmonary coarctation in the univentricular heart.

OBJECTIVE: The placement of a modified Blalock-Taussig shunt in patients suffering from pulmonary coarctation can result in the aggravation of uneven pulmonary blood flow. This may subsequently obviate the possibility of future performance of the Fontan procedure. The objective of this study was to evaluate mid-term results in patients with pulmonary coarctation who had undergone the placement of a modified Blalock-Taussig shunt, coupled with a pulmonary artery angioplasty. METHODS: We retrospectively reviewed the records of 13 patients who had undergone the placement of a modified Blalock-Taussig shunt, coupled with concomitant pulmonary angioplasty, between September 1998 and August 2002. All patients received follow-up angiographic evaluations. RESULTS: On the ipsilateral side of the modified Blalock-Taussig shunt, we observed a significant increase in the pulmonary artery index during a mean follow-up period of 11+/-5 months (preoperative 82+/-37 mm2/m2, follow-up 129+/-57, p=0.03). On the contralateral side, we also observed a significant increase in the pulmonary artery index (preoperative 90+/-56 mm2/m2, follow-up 137+/-56, p=0.047). There was one late death. During the follow-up period (mean 23+/-18 months), 10 patients received either a bidirectional or total cavopulmonary shunt and five of these patients underwent extracardiac Fontan operations. CONCLUSIONS: Our study demonstrated that the placement of a modified Blalock-Taussig shunt, with concomitant pulmonary artery angioplasty, constitutes a good initial surgical strategy in cases of univentricular heart with pulmonary coarctation.     

A case for anatomic correction in atrioventricular discordance? Effects of surgery on tricuspid valve function

OBJECTIVE: To assess tricuspid valve function in atrioventricular discordance after palliative procedures (pulmonary artery banding and Blalock-Taussig shunt) and corrective procedures (anatomic and physiologic repair). METHODS: Tricuspid valve dysfunction was assessed by transthoracic echocardiography and graded as no regurgitation (0), mild (1), moderate (2), and severe (3) before and after palliative and corrective procedures performed in 97 patients with atrioventricular discordance between 1988 and 1999. Thirty-two percent had an isolated ventricular septal defect, 43% had a ventricular septal defect and pulmonary stenosis, and 16% had pulmonary stenosis. Twenty-six patients underwent pulmonary artery banding and 28 had a Blalock-Taussig shunt. Seventy patients underwent physiologic and 19 underwent anatomic repair. Six patients underwent one-ventricle repair. RESULTS: After pulmonary artery banding, the tricuspid regurgitation score decreased from 1.7 +/- 0.8 to 0.9 +/- 0.6 (P <.001). In patients who underwent a Blalock-Taussig shunt, the tricuspid regurgitation score increased from 0.7 +/- 0.5 preoperatively to 1.4 +/- 0.6 postoperatively (P <.001). After physiologic repair, there was no significant change in the tricuspid regurgitation score; however, 7 patients required additional repair or replacement. The regurgitation score was significantly reduced from 1.5 +/- 0.8 to 0.4 +/- 0.5 (P <.001) after anatomic repair. The operative mortality in patients who underwent physiologic repair was 7% as compared with 0% in the anatomic repair group (P =.59). The median follow-up was 3.2 years. CONCLUSIONS: Right ventricular volume loading (shunt) worsens tricuspid regurgitation, whereas volume reduction (banding) or left-to-right septal shift (anatomic repair) has beneficial effects. We have not observed a significant change in the tricuspid regurgitation score after physiologic repair. Anatomic repair can be performed in selected patients with atrioventricular discordance and provides superior functional results.     

Classic Blalock-Taussig shunt in neonates

BACKGROUND: The choice of palliative procedure for neonates with congenital cyanotic heart defects remains controversial. Several reports have questioned whether the classic Blalock-Taussig shunt is adequate in neonates, because it shows a high rate of mortality and early shunt failure. The purpose of this study is to evaluate the early and late results of classic Blalock-Taussig shunt in neonates. METHODS: From December 1981 to December 1996, 31 neonates underwent a classic Blalock-Taussig shunt. Mean age at operation was 15.9 days (range, 2 to 28 days), and mean body weight was 3214 g (range, 2229 to 4468 g). The major diagnoses were pulmonary atresia with intact ventricular septum (6 patients) and with ventricular septal defect (4), univentricular heart (6), tricuspid atresia (5), tetralogy of Fallot (4), transposition of the great arteries (3), and double outlet right ventricle (3). RESULTS: There were no early deaths. There was one early shunt failure. The patient underwent a replacement of Blalock-Taussig shunt by vascular graft on the 1st postoperative day. Two patients with non-confluent central pulmonary artery underwent a contralateral modified Blalock-Taussig shunt on the 22nd and 42nd postoperative day, respectively. There were two late deaths before the definitive repair was performed. Twelve patients required an additional shunt operation. The mean interval between the initial and the second shunt procedure was 27.7 months (range, 6 to 67 months). Ten patients underwent definitive operation and the mean interval to that procedure was 55.5 months (range, 14 to 121 months). Shunt patency was 94.7+/-5.1% at 3 years. The freedom from cardiac event (cardiac deaths or repeat shunting procedure) was 80.5+/-7.1% at 1 year and 54.9+/-9.4% at 3 years. CONCLUSIONS: The classic Blalock-Taussig shunt has a low operative mortality and has provided excellent long-term palliation in the neonate. We conclude that a classic Blalock-Taussig shunt should be considered a reasonable choice in neonates requiring a palliative procedure for congenital cyanotic heart defects.     

Systemic-pulmonary shunts in infants and children. Early and late results

From September, 1978, to January, 1983, 44 cyanotic infants and children underwent a systemic-pulmonary artery shunt for the treatment of reduced pulmonary blood flow. Age ranged from 18 hours to 4 years (mean age = 0.49 years). Weight ranged from 1.7 kg to 13.2 kg (mean weight = 4.9 kg). There were 12 classic Blalock-Taussig shunts, five central polytetrafluoroethylene shunts, six interposition modified Blalock-Taussig shunts, and 21 Great Ormond Street type of modified Blalock-Taussig shunts. No direct aorta-pulmonary artery anastomoses were performed. There was one postoperative death (1/44 = 2.3%) in a 1,700 gm neonate born with pulmonary atresia and intact ventricular septum (shunt patent). Four shunts required early revision: one thrombosed central shunt, a kinked patent interposition Blalock-Taussig shunt, a small but patent Blalock-Taussig shunt, and one excessive Great Ormond Street type of Blalock-Taussig shunt. Two late deaths were probably shunt-related: one Blalock-Taussig and one central. All four types of shunts provided good palliation, but the Great Ormond Street type of Blalock-Taussig shunt is our preferred shunt because of (1) low operative risk, (2) predictable patency (100% in our series), (3) lack of distortion of pulmonary arterial anatomy, and (4) technical ease of insertion as well as takedown.     

Pulmonary atresia with intact ventricular septum: is neonatal repair advisable?

The optimal management of pulmonary atresia with an intact ventricular septum in the neonate remains controversial. The introduction of balloon septostomy and prostaglandin has significantly reduced early mortality but early surgical intervention is necessary to obtain a more adequate pulmonary blood flow. Fourteen neonates with pulmonary atresia and an intact ventricular septum were admitted to the Wessex Cardiothoracic Unit, Southampton from 1979 to 1986. Thirteen patients underwent cardiac catheterization. Cardiac catheterization data and right ventricular angiograms were reviewed retrospectively. Four patients with tripartite ventricles underwent total repair. The others received various palliative operations (valvotomy + modified Blalock-Taussig shunt or modified Blalock-Taussig shunt alone). Retrospective analysis of the angiograms indicated that right ventricular morphology alone is not a satisfactory criterion for surgical management. We have been able to demonstrate that there is a good correlation between the diameter of the tricuspid valve and the diameter of the infundibulum and that successful neonatal repair is possible when the tricuspid valve diameter is above 80% of the normal value for weight and when the tricuspid valve diameter to infundibular diameter ratio (TV/Inf ratio) is 2.2 or less. In patients with a tripartite ventricle but inadequate TV diameter and TV/Inf ratio, a closed pulmonary valvotomy with a modified Blalock-Taussig shunt remains the treatment of choice.     

A case of a patient with the non-confluent main pulmonary artery with the left pulmonary artery after a left Blalock-Taussig shunt for tetralogy of Fallot, which underwent a successful two staged radical repair

We report on a 14-year-old girl with tetralogy of Fallot and the non-confluent main pulmonary artery with the left pulmonary artery after a left Blalock-Taussig shunt. She underwent a left-sided classic Blalock-Taussig shunt at the age of one. However, she showed repeated dyspnea and increasing cyanosis, and cardioangiography showed the non-confluent main pulmonary artery with the left pulmonary artery. Corrective surgery of tetralogy of Fallot was done by a two-staged operation. In the first stage, a EPTFE prosthesis was grafted between the main pulmonary artery and the left pulmonary artery, and in the second stage, intracardiac operation was performed. The late postoperative status and hemodynamic results were satisfactory and we emphasize the rational for this approach.     

Growth of the Subclavian Artery and the Anastomosis in Blalock-Taussig Shunt: Absorbable Versus Nonabsorbable Suture

Background. We evaluated the growth of Blalock-Taussig shunts placed with absorbable suture by cineangiographic findings and long-term results and compared them with those in an earlier group of patients in whom we used nonabsorbable suture.

Methods. Eighty-one patients had postoperative cineangiography 1 year or more after a Blalock-Taussig shunt procedure. From September 1985 to December 1994, 40 patients (group I) underwent a Blalock-Taussig shunt procedure with the use of absorbable polydioxanone suture, and from January 1980 to August 1989, 41 (group II) underwent the same operation with nonabsorbable polypropylene suture. Cineangiograms were reviewed to assess shunt patency and growth of the subclavian arteries and the subclavian artery–pulmonary artery anastomoses.

Results. At the Blalock-Taussig shunt operation, mean outer diameters of the subclavian artery and the anastomosis in group I were 3.8 ± 0.1 mm and 4.1 ± 0.1 mm, respectively and 3.9 ± 0.1 mm and 4.0 ± 0.1 mm in group II. The mean inner diameters of the subclavian artery and the anastomosis measured in postoperative cineangiograms were 7.9 ± 0.5 mm and 4.6 ± 0.2 mm, respectively in group I and 6.6 ± 0.4 mm and 3.1 ± 0.2 mm in group II. The diameters of both the subclavian artery (p < 0.05) and the anastomosis (p < 0.001) were significantly greater in group I than in group II. Five years after operation, 71.1% ± 7.4% of patients in group I and 54.8% ± 8.0% in group II had good palliation.

Conclusions. The use of absorbable polydioxanone suture has an advantage in terms of growth of the diameters of the subclavian artery and the anastomosis in a Blalock-Taussig shunt and may improve the long-term results after this shunt operation in infancy.     

Classic shunting operations as part of two-stage repair for tetralogy of Fallot.

One hundred forty-nine consecutive patients with tetralogy of Fallot, with or without pulmonary atresia, underwent Blalock-Taussig or Waterston operation for initial palliation. Of these patients, 45 were less than 6 months old, and 63 were less than 1 year old. The type of shunt, and the presence or absence of pulmonary atresia did not have a significant effect (p greater than 0.2) on hospital mortality. Parametric analysis showed a significant effect of age (p = 0.03), the risk of hospital death being 6% at 1 month of age, 4% at 3 months, 3% at 6 months, and 2.5% at 12 months. No late deaths occurred before the age of 3 years. Six patients (4.2% of the hospital survivors) required another operation before they were 3 years old. Severe arm ischemia occurred after a Blalock-Taussig shunt in 1 infant with Down's syndrome.     

Pulmonary atresia with intact ventricular septum: strategy based on right ventricular morphology

OBJECTIVES: Management strategy for pulmonary atresia with intact ventricular septum is controversial. We treated patients with this anomaly according to a management protocol based on our quantitative assessment of right ventricular morphology (index of right ventricular development and right ventricle-tricuspid valve index). In the present study, we reviewed a 20-year experience of the surgical treatment at our institution to define guidelines for selecting the appropriate type of surgical procedure. METHODS: Between April 1981 and June 2002, 45 consecutive patients with pulmonary atresia with intact ventricular septum underwent surgical treatment. Open transpulmonary valvotomy was performed in 27 patients and Blalock-Taussig shunt in 18 patients as the initial palliative procedure. Three patients who underwent a successful transpulmonary valvotomy alone in the neonatal period required no further operation. Definitive repair was performed in 32 patients. Biventricular repair was performed on 19 patients, one and a half ventricular repair in 3, and Fontan-type operation in 10. RESULTS: There were 1 early and 2 late deaths before the definitive operation in patients who underwent transpulmonary valvotomy. Two patients who had coronary artery interruption died 3 months and 13 years after the initial Blalock-Taussig shunt. There were 1 early and 2 late deaths after the definitive operation. Actuarial survival, including noncardiac death, was 91.1% at 5 years after the initial procedure and 81.5% at 10 years. CONCLUSIONS: We treated patients with pulmonary atresia with intact ventricular septum according to a management protocol based on our quantitative assessment of right ventricular morphology with good results.     

Reoperation of Blalock-Taussig shunt for double outlet right ventricle and pulmonary atresia in an adult

A 36-year-old man was admitted to our hospital due to dyspnea and pneumonia. He had undergone left classical Blalock-Taussig shunt at 5 years old and right modified Blalock-Taussig shunt at 16 years old, because he was judged as no indication for any radical operation. Since the last surgery, he had stopped visiting hospital. Computed tomography showed pneumonia and pulmonary embolism in the left lower lung and occlusion of the right modified Blalock-Taussig shunt. After pneumonia was improved by antibiotic treatment, he underwent reoperation of the right modified Blalock-Taussig shunt using 8 mm knitted Dacron graft. Postoperative course was uneventful and dyspnea and cyanosys were improved. We successfully treated a complicated case of an adult congenital heart disease by reoperation of the right modified Blalock-Taussig shunt.     

Palliative surgery in tetralogy of Fallot

Because much controversy surrounds the palliative surgical treatment of young children with tetralogy of Fallot the authors review their experience over 13 years with two procedures--the Blalock-Taussig operation and the Waterston shunt. Blalock shunts were performed 195 times in 172 patients; 147 had a single Blalock anastomosis which carried them through the critical period and allowed for later correction of the tetralogy. Thrombosis of the Blalock anastomosis occurred in two patients in the early postoperative period. In 23 patients a second shunt was necessary after the first Blalock shunt became inadequate in spite of being patent. The age of the children ranged from 2 weeks to 9 years, 74% being operated upon under the age of 2 years. There were four early deaths (2%) and five late deaths (2.5%) in this group. Of the last 91 consecutive patients operated upon between Sept. 1, 1972 and June 30, 1980 none have died. Between September 1968 and June 1980, 14 patients with tetralogy of Fallot underwent a Waterston shunt. Their ages ranged from 2 days to 4 years. Six patients were younger than 35 days at the time of operation. There were two operative deaths in this group. The Waterston shunt carries a high risk and is reserved for the occasional patient who needs palliation during the first weeks of life and in whom the anatomy of the subclavian artery does not favour a good Blalock-Taussig shunt. The Blalock-Taussig operation is preferred because it is safe and gives good sustained clinical results. The mortality was much lower than previously reported. The growth of the pulmonary arteries was good in most patients. The Blalock shunt did not increase the pulmonary resistance and it did not influence the operative mortality.     

Reverse Blalock-Taussig shunt facilitates the growth of the ascending aorta after hybrid palliation

A 13-day-old baby girl with tricuspid atresia (IIc), who was prematurely born at 32 weeks and 5 days of gestation and weighed 2.2 kg, underwent bilateral pulmonary artery banding, ductal stenting, and reverse Blalock-Taussig shunt. Cardiac computerized tomography at 4 months postoperatively showed that the ascending aorta outgrew the somatic growth, presumably thanks to the forward flow through the reverse Blalock-Taussig shunt. At 6 months postoperatively, the patient underwent a successful second-stage operation.     

Assessment of Blalock-Taussig shunts in children with complex cardiac anomalies associated with reduced pulmonary blood flow and total anomalous pulmonary venous drainage]

Eleven patients with syndromes of asplenia and polysplenia associated with total anomalous pulmonary venous drainage (TAPVD) were underwent Blalock-Taussig (B-T) shunt operation for reduction of pulmonary blood flow. The age of patients at operation were 6 days to 5 years (average 19.5 +/- 18.7 month). There were seven patients in supracardiac type and four in cardiac type of TAPVD. All patients didn't present obstruction to pulmonary venous return (PVO) before B-T shunt operation. There were one early (9%) and two late deaths (20%) after surgery. Although the hospital death was related to perioperative errors. Two late deaths were not due to the PVO. One of infants had moderately pulmonary congestion and cardiac failure after shunt procedure. Two patients were measured pressure gradient (3 to 4 mmHg) between common pulmonary vein to atrium chamber before shunt procedure. Repeated catheterization revealed that 6 of them could be measured pressure gradient, 3 to 7 mmHg, and no patients had clinical sign of the PVO. Our results demonstrated that B-T shunt operation could be satisfactory for syndromes of asplenia and polysplenia associated with reduced pulmonary blood flow and TAPVD.     

Pulmonary thromboembolism after one and a half ventricle repair

Acute pulmonary thromboembolism in a patient who had undergone bidirectional Glenn anastomosis was treated by percutaneous selective intravascular thrombolysis. A 20-year-old woman was diagnosed with pulmonary stenosis and right ventricular hypoplasia, complete occlusion of the left pulmonary artery secondary to a Blalock-Taussig shunt, and atrial septal defect. The patient developed thromboembolism of the subsegmental branches of the right pulmonary artery resulting in critical hemodynamic deterioration 2 weeks after undergoing one and a half ventricle repair (bidirectional Glenn shunt). The patient was treated with tissue plasminogen activator administered directly into the right pulmonary artery via an intravascular catheter. Progressive recanalization of the obstruction began immediately. Pulmonary angiography 3 months after thrombolytic therapy demonstrated patent subsegmental vessels. Early detection of the pulmonary thromboembolism and prompt intervention are crutial to relieving this fatal complication after a Fontan operation.     

Staged operation for right isomerism with total anomalous pulmonary venous return: report of a case

A male infant with right isomerism, single ventricle, severe pulmonary stenosis (PS), and total anomalous pulmonary venous return (TAPVR) underwent successful staged Fontan operation. Pulmonary vein drained into right superior vena cava without a stenotic lesion. Common pulmonary venous chamber was also connected with the atrium by a thin bridging vein. Blalock-Taussig shunt was performed at 2-month-old. Because of progressive pulmonary congestion, an anastomosis between common pulmonary venous chamber and the atrium followed 4 days after the first shunt. Bidirectional cavopulmonary shunt was performed 7 months after the second operation. Because of progressive atrioventricular valve regurgitation, repeated bandings of the shunt were required to regulate the pulmonary flow. Total cavopulmonary connection was completed 9 months after the BCPS. Staged operation is a useful strategy to acquire an appropriate pulmonary blood flow for the isomeric heart with TAPVR and severe PS.     

Adjustable tourniquet to manipulate pulmonary blood flow after Norwood operations

Background. Survival after first-stage palliative Norwood operations for single ventricle with systemic outflow obstruction is mainly dependent on a balanced ratio of pulmonary blood flow to systemic blood flow. Here we report the clinical results using a modified technique that allows a controlled systemic-to-pulmonary shunt flow to prevent pulmonary overcirculation.

Methods. From 1995 to 1998, of 26 infants undergoing first-stage palliative Norwood operations, 7 had placement of an adjustable tourniquet around a modified right Blalock-Taussig shunt.

Results. Hospital survival was 20 of 26 patients (77%). All 7 patients in whom snaring of the shunt was indicated survived. Two patients underwent repeated adjustment, in 5 patients the tourniquet could be removed during delayed sternal closure, and 2 patients were discharged with the shunt partially snared.

Conclusions. The snare-controlled systemic-to-pulmonary shunt allows improved hemodynamic stability after reconstructive surgery for hypoplastic left heart syndrome or other similar complex cardiac defects by reducing the risk of pulmonary overcirculation. It is simple and rapidly executed. The option of graded banding of the shunt depending on the hemodynamic situation increases flexibility and safety after cardiopulmonary bypass or at any time in the postoperative period.     

Indication for systemic-pulmonary artery shunts guided by two-dimensional and Doppler echocardiography: criteria for patient selection

From June, 1983, to February, 1987, 91 patients with pulmonary outflow tract obstruction underwent a systemic-to-pulmonary artery shunt without an invasive study. The surgical indication was based on two-dimensional (2-D) and Doppler echocardiography only. In 82 patients (90.1%), 2-D and Doppler echocardiography allowed correct assessment of the intracardiac anatomy and of the morphology of the pulmonary arteries, pulmonary veins, and aortic arch. The aortic arch anatomy was misdiagnosed in 6 patients (6.6%) who underwent a modified instead of a classic Blalock-Taussig shunt. In 3 patients (3.3%), the indication for the systemic-pulmonary artery shunt was inappropriate; in 1, operative death resulted from the incomplete diagnosis. After the preselection of patients based on knowledge of the anatomical patterns, a systemic-pulmonary artery shunt may be performed without cardiac catheterization if these rules for definitive patient selection are followed: (1) accurate clinical assessment to identify the patients with restricted pulmonary blood flow; (2) precise intracardiac diagnosis by 2-D and Doppler echocardiography; and (3) definitive 2-D echocardiographic visualization of the pulmonary venous connection and the confluence of the pulmonary arteries.     

Blalock-Taussig shunts in the infant

Eighteen consecutive patients 3 to 30 months of age underwent Blalock-Taussig shunt for palliation of cyanotic congenital heart disease. Nine patients weighed less than 8 kg. Follow-up has ranged from 12 to 62 months. All shunts have remained patent, and in none of the patients has a second shunt been required. The Blalock-Taussig shunt provides useful palliation for cyanotic congenital heart disease during the first 2 years of life.