Systemic-pulmonary artery anastomoses in infancy

Transcatheter recanalization and subsequent stent implantation for the treatment of early postoperative thrombosis of modified Blalock-Taussig shunts in two children

Two babies with duct-dependent cyanotic congenital heart disease were palliated with modified Blalock-Taussig shunts. One patient was diagnosed to have tetralogy of Fallot, and the other patient, tricuspid atresia type Ia. Early postoperative arterial oxygen saturations dropped significantly due to shunt thrombosis. Both patients were successfully treated with angioplasty and stent implantation.

Results of 546 Blalock-Taussig shunts performed in 478 patients

Between 1983 and 1995, 546 Blalock-Taussig shunt procedures were performed in 472 patients: 128 (23.0%) were classical shunts, 90 of them on the same side as to the aortic arch, and 418 (77.0%) were modified shunts, 182 on the same side of the arch. At the time of surgery, 78 patients were aged below one week, 270 from one week to 12 months, and 198 patients were over one year of age. The mean pre-operative arterial saturation (71.7% +/- 16.5%) was significantly increased to 83% +/- 17.9% immediately after the procedure (p=0.017). The overall hospital mortality rate was 2.9% (16/546), with rates of 2.3% (3/128) for the classical, and 3.1% (13/418) for the modified shunts (p=not significant). The rate was significantly higher, however, for classical shunts when the pulmonary arterial diameter was less than 4 mm (15.4% versus zero; p=0.047), though this relationship was reversed for modified shunts (zero versus 3.6%; p=0.338). Early mortality was significantly influenced by the age at surgery, 5/78 (6.4%) in patients aged below 1 week, 3.7% between 1 week and 1 year, and 0.5% over 1 year (p=0.019). Early mortality was also significantly increased in patients weighing 3kg or less, 8/156 (5.1%), versus 3/303 (1.0%), p=0.037. Overall, 51 shunts failed (9.3%), 10 early and 41 late. Early failure was significantly increased in patients weighing 3kg or less, 8/156 (5.1%) versus 3/303 (1.0%), p=0.016. The overall early failure rate was 1.4% (3/215) when heparin was administered intra-operatively and for 48 hours postoperatively, in contrast to an early failure rate of 3.4% (7/203) when heparin was not used (p=0.294). Overall rates of failure during follow-up were 9.1% (17/188) in heparinized patients versus 13.6% (24/177), (p=0.173) in non-heparinized patients. Failure of classical shunts was 10.2% (13/128), compared with 6.7% (28/418) for modified shunts (p=0.195). Failure was more common overall if the pulmonary arterial diameter was less than 4 mm, 14.7% (9/61), as opposed to 8.7% (26/300) when the diameter was 4 mm or greater, (p=0.144). Administration of aspirin during follow-up after the modified shunt procedure reduced failure from 11% (18/163) to 6.7% (10/150), p=0.176. Classical or modified Blalock-Taussig shunts, either on the same side or opposite to the aortic arch, can be performed on patients of any age with minimum postoperative complications and low operative mortality. The use of intra- and post-operative heparin appears to reduce the overall rate of failure, and the administration of aspirin during follow-up appears to reduce failure of modified Blalock-Taussig shunts.

Ascending aorta to right pulmonary artery interposition shunt in critically ill infants

In spite of a trend toward earlier complete repair, some neonates and infants with complex cyanotic heart disease continue to require interim palliation with systemic-to-pulmonary artery shunts. A variety of shunt procedures have been proposed, each with inherent advantages and disadvantages. We have found a prosthetic interposition shunt between the ascending aorta and right pulmonary artery (AA-RPA) to be effective in very young infants with small vessels. Over a 15-year period, 51 patients, mean weight 3.33 kg and mean age 59 days, underwent this procedure with a 13% perioperative mortality and a 78% 2-year overall shunt patency rate. We conclude that the AA-RPA interposition shunt is a safe, effective procedure in these infants.

The Blalock-Taussig shunt: an analysis of trends and techniques in the fourth decade

The original description of the Blalock-Taussig shunt was published in 1945 and represented the first direct surgical procedure for the treatment of cyanotic congenital heart disease. The present study analyzes the results of Blalock-Taussig shunts performed at Duke University Medical Center during the fourth decade since the original description of the procedure. From 1975 to 1984, 53 classic and 24 modified Blalock-Taussig shunts were performed with a hospital mortality of 8%. These deaths occurred in critically ill patients with either pulmonary atresia or complex congenital cardiac lesions. The results of the early group (1975-1979) were compared to the late group (1980-1984) of patients. There was a greater proportion of infants less than 1 week of age in the late group, and the actuarial event-free shunt survival following operation was significantly better in the late group. This improvement in the late group was apparent both in patients receiving classic and modified Blalock-Taussig shunts and probably represents the effects of advances in microsurgical technique as well as improvement in the support of critically ill infants at the time of surgery by pediatric anesthesiologists and neonatologists. The data in the present study indicate that the mortality associated with Blalock-Taussig shunting is related to the condition of the patient at the time of surgery and the underlying cardiac pathology rather than the age of the patient at the time of shunting. The efforts to further reduce morbidity and mortality associated with Blalock-Taussig shunting should therefore be directed primarily to the support of infants during the preoperative and intraoperative phases of care.

The Blalock-Taussig shunt in infants: standard versus modified

In recent years, the modified Blalock-Taussig shunt--a polytetrafluoroethylene graft from the subclavian artery to the pulmonary artery--has been preferred over the standard shunt by some surgeons because (1) it requires less dissection and (2) length of native vessels is not critical. From January, 1979, to June, 1985, we operated on 51 infants less than 1 year of age, including 26 less than 1 week of age, to palliate severe complex cyanotic congenital cardiac malformations. Twenty-four modified Blalock-Taussig shunts and 29 standard Blalock-Taussig shunts were created. The groups were concurrent. We reviewed all available cineangiograms and measured branch pulmonary and subclavian arteries. Pulmonary artery index was not different preoperatively in patients given a modified versus a standard Blalock-Taussig shunt (144 +/- 118 and 118 +/- 59 mm2/m2, respectively), but it was greater postoperatively in patients with a modified shunt (431 +/- 188 and 189 +/- 106 mm2/m2) (p = 0.07). Distortion of the pulmonary artery occurred less often after a modified Blalock-Taussig shunt (4/11) than a standard Blalock-Taussig shunt (6/8) (p = 0.06), though none of the distortions was severe. Early and late shunt failure occurred less often with a modified shunt (5/24) than with a standard shunt (15/29) (p less than 0.05). The modified Blalock-Taussig shunt had advantages over the standard Blalock-Taussig shunt in our series: pulmonary artery growth was greater, distortion of pulmonary arteries was less commonly seen, and shunt failure occurred less often. Thus, in infants, we believe the modified Blalock-Taussig shunt should be considered a reasonable alternative to the standard Blalock-Taussig shunt.

A comparison of Blalock-Taussig, Waterston, and polytetrafluoroethylene shunts in children less than two weeks of age

Results obtained with Blalock-Taussig, Waterston, and polytetrafluoroethylene (PTFE) shunts were compared in 67 cyanotic infants less than 2 weeks of age. A different shunt was preferably used at each of three institutions. The incidences of early shunt failure (3 out of 21, 14%), mortality after revision of early shunt failure (0 out of 3), and overall hospital mortality (1 out of 21, 5%) were all lowest for the PTFE shunt. Incidence of congestive heart failure secondary to excessive flow was comparable for the Blalock-Taussig and PTFE shunts, both of which were lower than the Waterston shunt. Cumulative probabilities of late shunt adequacy were calculated for hospital survivors. At 1 year, all shunts provided comparable adequate palliation (greater than 80%). Probability of late shunt failure was significantly higher (p = 0.04) for the PTFE shunt at 3.5 years. Results suggest that the PTFE shunt may be the safest and most effective shunt in neonates, but that elective shunt replacement or total repair may be warranted in the first or second year of life.

Use of saphenous vein allografts for aortopulmonary artery anastomoses in neonates with complex cyanotic congenital heart disease

A saphenous vein allograft was used to create an aortopulmonary communication in 16 infants with cyanotic congenital heart disease and ductus-dependent pulmonary blood flow. These grafts measured from 3 to 8 mm in diameter and were placed between the aorta and main pulmonary artery in eight patients, between aorta and right pulmonary artery in eight, and between aorta and left pulmonary artery in one (one child had two grafts). Before heparin was used, early in the series, four of these grafts occluded and three of the four infants died during attempted revision. Another infant died early from renal failure. Late mortality has claimed four: one from cerebral hemorrhage, two from hypoxia, and one at open-heart surgery for repair. There are eight late survivors (50%). Most of the allografts were used before small diameter Gore-Tex was available; in more recent patients, 4- to 6-mm Gore-Tex grafts have been used. In our most recent patient, however, the attempt to place a Gore-Tex graft was unsuccessful, but the more pliable saphenous vein graft was readily placed and an adequate shunt obtained. Both the saphenous vein graft and the Gore-Tex have the advantage of providing pulmonary flow without the higher risk of congestive failure or pulmonary hypertension seen in patients with a Waterston or Potts anastomosis. They are easier to perform, require less anesthesia time than the Blalock-Taussig shunt, last as long as the Blalock-Taussig when done under similar conditions, and are easy to take down at the time of total repair.

Subclavian-pulmonary artery shunts with polytetrafluorethylene interposition grafts

Systemic-pulmonary artery shunts remain an important treatment in cyanotic patients. Central shunts continue to pose early and late problems when standard Blalock-Taussig shunts are not possible. Twenty patients underwent subclavian-pulmonary artery shunt procedures with polytetrafluoroethylene (PTFE) prostheses between October, 1980, and August, 1982. Their ages ranged from 1 day to 15 years; 11 patients were less than 14 days old. The arterial oxygen tension rose from 30.7 +/- 11.9 mm Hg to 51.3 +/- 9.1 mm Hg (standard deviation; p less than 0.001) and from 26.4 +/- 7.5 mm Hg to 50.5 +/- 9.3 mm Hg (p less than 0.001) among the 11 neonates. There were no hospital deaths and only 2 late deaths (not shunt related). All patients have patent shunts and excellent relief of cyanosis. The 18 survivors have been followed for an average of 19 months (range, 7 to 29 months). No patient has required reoperation for shunt inadequacy or thrombosis. Recatheterization in 11 patients has demonstrated normal pulmonary pressures and good pulmonary artery growth without vessel distortion. Subclavian-pulmonary shunts using PTFE provide long-term palliation in cyanotic patients. This type of shunt appears to offer important advantages over other shunt procedures, including the classic Blalock-Taussig operation, in newborns.

Systemic-Pulmonary shunts inneonates and infants using microporous expanded polytetrafluoroethylene: immediate and late results

Thirty infants with various types of cyanotic congenitl heart disease underwent systemic-pulmonary artery shunts with a microporous polytetrafluoroethylene (PTFE) graft between May, 1976, and July, 1979. Sixteen of them were less than 1 month old, and the average age of the neonates was 5.3 days. There were no operative deaths and 5 hospital deaths, 2 related directly to the shunt. Five patients required early revision of the shunt. Relief from cyanosis was achieved in each patient. Twenty-five patients have been followed up to three and one-half years. There have been 2 late deaths and one late occlusion of the shunt. One patient outgrew the shunt and required secondary shunting procedures. Three of 30 patients have evidenced mild congestive heart failure, which has responded to digitalis. Because of the reliability and excellent late patency of the PTFE prosthesis, we consider it to be superior to a central or Potts shunt for relief from cyanosis in the neonate and infant, and as reliable as a Blalock-Taussig shunt.

Construction of interposition polytetrafluoroethylene ascending aorta-pulmonary artery shunt

The technique for constructing an ascending aorta-right pulmonary artery interposition shunt using a short segment of polytetrafluoroethylene is described. This technique has been used in 8 neonates ranging from 1 day to 11 months old. There has been 1 shunt-related death. There have been no clotted grafts or graft kinking noted. A continuous running suture placed before the graft is lowered into position facilitates exposure and suture placement. A median sternotomy or sternal transection has not been necessary.

Aorta-pulmonary artery shunts with expanded polytetrafluoroethylene (PTFE) tube

Ten patients underwent an aortapulmonary artery shunt with a polytetrafluoroethylene (PTFE) tube between December, 1976, and October, 1977. Five of them were less than 1 month old. The diameter of the PTFE tube was 5 mm in 9 patients and 4 mm in 1 patient. Seven patients survived the operation. One of them had a clotted shunt, which was reoperated on successfully. Three patients died in the postoperative period, and all had a patent shunt. Overall patency was 90% (9/10). Congestive heart failure refractory to medical treatment developed in 1 patient with a patent Blalock-Taussig and PTFE shunt. In our institution, the Blalock-Taussig shunt is the procedure of choice. The PTFE shunt is used when the anatomy of a patient is unsuitable for a Blalock-Taussig shunt. A tube diameter of 5 mm is optimal for infants when further growth is considered, even if digitalization is necessary to control congestive heart failure.

The Blalock-Taussig shunt in the first two years of life: a safe and effective procedure

Many surgeons have been reluctant to perform Blalock shunts in patients who are in infancy or early childhood (less than 24 months old) and have done instead direct aortopulmonary anastomoses. Recently, others have advocated complete repair of tetralogy of Fallot in early infancy because of the high mortality of direct aortopulmonary shunts. We believe the Blalock-Taussig anastomosis is a safe and effective palliative procedure for all infants with inadequate pulmonary blood flow regardless of size. During the past nine years, 24 babies less than 2 years old who were followed had construction of Blalock-Taussig anastomosis for inadequate pulmonary blood flow. There were no operative deaths and no shunt-related late deaths. Of the 24 babies, 12 were less than 12 months old. Eighteen of the 24 had tetralogy of Fallot. The remaining 6 had a variety of lesions with inadequate pulmonary blood flow. The mean weight of the entire group was 7.3 +/- 1.6 kg. Of those infants less than 12 months old, the mean weight was 6.8 +/- 2.0 kg. More than 6 months following construction of the shunt, 2 babies died from sepsis unrelated to cardiovascular status. All infants had adequate but not excessive pulmonary blood flow after shunting. There were no late shunt failures.

Current results with construction and interruption of the Waterston anastomosis

The Waterston anastomosis was constructed in 21 infants and neonates between 1973 and 1977. Sixteen neonates were 1 week old or less and 8 were less than 24 hours old. There were 2 operative deaths, giving a hospital survival of 90%. There were 3 late deaths. All surviving infants received satisfactory palliation except 1 who required a Potts anastomosis one year later. During the same time interval, 9 other patients who had had a Waterston anastomosis underwent complete intracardiac repair. Seven of them had significant angulation of the right pulmonary artery necessitating patch reconstruction. All patients survived operation, and follow-up pulmonary angiograms demonstrated only a slight persistent narrowing of the right pulmonary artery in 2 patients. We conclude that the Waterston anastomosis can be constructed with a low operative mortality even in the severely cyanotic neonate and that it can be taken down at the time of complete repair with minimal morbidity and no mortality even if it has significantly angulated the right pulmonary artery.

Modified Blalock shunts utilizing pericardial tube grafts

In the last decade, 14 patients underwent an aorticpulmonary shunt for cyanotic heart disease, at which time the subclavian artery was either deemed too small or too short to function satisfactorily as a Blalock shunt. In each case a rectangular piece of pericardium was excised, rolled into a tube, and sutured down one edge to create a tube graft. One end of the graft was sutured to the stump of the subclavian artery near its takeoff and the other end was sutured end-to-side to the corresponding pulmonary artery. During the same period, 5 children had azygos vein grafts and 2 had Teflon grafts inserted to create a modified Blalock shunt. This article will discuss the indications, techniques, and long term results of aorticpulmonary shunts of all types, and more specifically the complications and long term results in patients where these grafts were used.