Study sheds doubt on Blalock Taussig shunts for infants
medwireNews: Use of a modified Blalock Taussig shunt (MBTS) for the treatment of biventricular and univentricular infant hearts is associated with significant mortality and morbidity, indicate Swiss study results.
Almost a tenth of the cohort died after receiving the shunt, and the same proportion experienced acute stunt thrombosis, although none died from this complication.
While the MBTS procedure is an established procedure that shows progressive improvements, lately the focus has been on primary corrective procedures, write the study authors in the European Journal of Cardio-Thoracic Surgery.
"An ideal shunt helps promote uniform growth of the pulmonary arteries, without causing distortion," say Hitendu Dave (University Children's Hospital Zurich) and colleagues.
Their findings show that "while small shunts may have a tendency to shunt thrombosis, large shunts may lead to pulmonary over-circulation and volume loading of the heart."
A total of three among 32 patients (9%) aged an average of 11 days died following MBTS for either a biventricular (n=21) or a univentricular heart (n=11). Lower body weight and bigger shunt size per kg of body weight (3.5 mm for infants of 3.0 kg or less, 3.5 mm for those of around 3.5 kg) both significantly increased the risk for mortality.
"These findings point towards over-shunting as a possible indicator of mortality in our series," suggest Dave and co-workers.
The same number of patients who died showed acute stent thrombosis within the first 24 hours of the procedure; however, this showed no statistical association with shunt size, or shunt size per kg body weight.
Overall, 10 infants required cardiac decongestive therapy, including 20% of biventricular hearts versus 20% of univentricular hearts. Bigger shunts were significantly associated with the need for this decongestive therapy, note Dave et al.
At the time of the study, almost all patients (97%) had undergone corrective surgery to remove the shunt, and none had died during or after the surgery.
While the researchers did not witness an association between an anticoagulation regimen and shunt thrombosis, "it does not belittle the role of postoperative anticoagulation, particularly in high-risk patients," they write.
"In spite of increasing confidence with primary neonatal intracardiac repairs, the MBTS continues to be indicated for malformations of the univentricular pathway," they conclude.
By Sarah Guy, medwireNews Reporter