Blalock Taussig type shunt palliation for cyanotic infants and children.AM Patwardhan, A Kaul, P Panjabi, SM Pantvaidya, KK Golam, SP Pandit, AP Chaukar
Dept of Cardiovasc Thoracic Surgery, LTMMC, Sion, Bombay, Maharashtra.
In a period of ten years from January 1, 1979 to December 31, 1988, 54 cyanotic patients weighing less than 10 kg underwent shunt operations of Blalock Taussig type. The indications were hypercyanotic spells, failure to thrive and pulmonary arteries being too small for safe total collection. The commonest diagnosis was tetralogy of Fallot (63%). Thirty-three (64%) patients were older than 1 year but still weighed less than ten kg. Mortality was 16.67% (70% C.L. 8.94-26.60). During follow-up, there were 4(7%) late deaths. During the same period, 134 patients less than 5 years age came to autopsy without having any cardiological or surgical intervention. Ninety-seven (72.4%) of these deaths were due to cardiac causes. In order to save their lives, early identification is necessary which highlights the importance of parent and primary physician education.
Keywords: Child, Preschool, Female, Heart Defects, Congenital, mortality,surgery,Human, Infant, Male, Methods, Palliative Care,
Shunt operations of Bialock-Taussig type are designed to connect the subclavian artery to the pulmonary artery directly or by using a prosthetic graft. The procedure increases pulmonary blood flow and therefore decreases cyanosis. Here we present our ten year experience with Bialock-Taussig type shunt palliation in patients with cyanotic congenital heart diseases and weighing less than 10 kg.
Between January 1, 1979 and December 31, 1988 54 cyanotic patients (34 males and 20 females) weighing less than 10 kg underwent Blalock Taussig type shunt for the following indications: a) hypercyanotic attacks or spells. b) failure to thrive and c) pulmonary arteries too small for safe corrective surgery.
Of these 54 patients, 34 had tetralogy of Fallot (TOF), 12 suffered from tricuspid atresia, 4 had univentricular heart with pulmonary stenosis (PS), 2 complex congenital heart diseases, 1 transposition of great arteries with ventricular septal defect (VSD) and PS and 1 pulmonary atresia with VSD. Age and weight wise distribution is shown in [Table - 1]. A point to note that though 33 patients were older than 1 year, they still weighed less than 10 kg.
Of the 54 shunt operations, 41 were of modified type (using 5 mm Goretex graft). Of these, 38 (70.3%) were done on the left side.
While analysing the incidence of mortality, 70% confidence limits were calculated using continuity correction. This was necessary due to small sample size. The hospital mortality was 16.67% (9 of 54 patients, CL 8.94-26.6%). A shunt was not constructed in one of the 54 patients, due to absence of hilar pulmonary arteries and this inoperable patient died during hospital stay. In the remaining, the hospital mortality of the procedure was 15.09% (8 of 53 patients). The causes of death were shunt thrombosis in three, metabolic causes in two, septicemia in one, low cardiac output in one, and an error in diagnosis in one. The latter had univentricular heart and pulomonary stenosis. Associated hypoplasia of the left atrioventricular valve and absence of interatrial communication were missed. Following the shunt operation this patient had repeated attacks of left sided failure.
In the first 5 years of our experience, the mortality was 6/28 (21.48%, CL 13.05-32.38) compared to 2/25 (8%, CL 2.7 - 17.73) over the last 5 years.
The analysis of mortality in the study population as per demographic parameters (age and weight) is given in [Table - 1]
As mentioned in the [Table - 1], the mortality incidence was found to be higher in children below 1 yr of age. Also, the rate was found to decrease with increase in weight.
[Table - 2] illustrates mortality analysis w.r.t. diagnosis. Patients with tetralogy of Fallot and tricuspid atresia had mortality similar to overall morality.
During the follow up, there were 4 late deaths in the 45 survivors. The causes were gastroenteritis with dehydration and toxaemia in one severe hemoptysis with airway obstruction in one, miliary tuberculosis in one and one death occurred due to cerebrovascular accident during a follow up cardiac catheterization. Of the remaining 41, 34 (75.56%) are alive with one shunt, two (4.44%) are alive with an additional shunt. One (2.22%) patient survived total correction, however four (8.89%) died after total correction.
During the same period of 10 years, 134 patients less than 5 years of age came to autopsy without having had any cardiological or surgical intervention. The mortality analysis is shown in [Table - 3]. Ninety-seven of these deaths (72.4%) were cardiac. Thus it is obvious that a large number of these patients could have been subjected to palliation.
Patients suffering from cyanotic congenital heart disease and weighing less than ten Kg are positively at a higher risk for cardiac cathertirization procedure. They do not tolerate excess dye load, hypoxia with acidosis and blood loss. Also the work load of a single cardiac catheterization laboratory is usually quite high. Therefore, such patients can be considered for palliation, when all information is available using two dimensional echocardiography. Classic or modified Bialock-Taussig shunts approach the ideal shunt criteria . In our experience with 54 cases over a 10 year period, these shunts have given excellent palliation. We however prefer to do modified shunts to prevent the problems of turning down the subclavian artery. Complex lesions would need further evaluation by cardiac cathetirization.
The hospital mortality of Bialock-Taussig type shunts in our hands has been 16.67%, which is significantly higher (p < 0.05) when compared to the other reports - 2.3% in 44 patients, 8% in 115 patients and 8% in 119 patients of Duke University Series. Our mortality is also higher in the non-TOF group (20.0%) against the TOF group (14.7%), but the difference is not significant as seen in the selected series of 898 patients - reported by Oldham et al.
Three of our deaths were due to shunt thrombosis. One shunt thrombosis occurred in a modified shunt using a 5 mm goretex graft in a 10 kg patient. Two of these occurred in patients weighing 2.9 kg and 3.0 kg, where classic Bialock-Taussig shunts were done on the side of the aortic arch. These two patients were operated in 1979 in the early part of our experience. We do not recommend a classical Bialock Taussig Shunt on the same side as the aortic arch.
In our series we still have a preponderence of tetralogy of Fallot patients (63%) whereas in most of the series TOF occupies a third place in frequency,. This is probably because patients with lesions other than TOF in our centre do not seem to come up for surgery.
Our autopsy data of patients aged less than 5 years during the same period shows 21 patients with TOF dying due to cardiac cause. Whereas, 76 patients with lesion other than TOF had a primary cardiac cause for death.
To prevent these deaths not only the aggressive diagnostic and therapeutic approaches are necessary but also the education of parents and primary physician is a must. This will help to prevent delay in treatment. Pharmacological approach involves therapy with PGE1 or PGE2 in neonatal period. However, these are not manufactured locally and have to be imported at high cost. Another problem is that they are not readily available. Therefore, active participation of pharmaceutical industries by manufacturing these life saving drugs is also welcome.
[Table - 1], [Table - 2], [Table - 3]