have drastic effects on resistance and blood flow. The pulmonary band can also migrate away from the original placement and lead to stenosis, in which the blood vessel becomes too narrow. There have also been reports of hardening of the vessels around the band due to buildup of calcium deposits and scarring of the pulmonary artery wall beneath the band, which can also inhibit blood flow. Additional surgeries to adjust band tightness occur in up to one-third of patients. Erosion of the band through the pulmonary artery has been reported, which can lead to the formation of blood clots. This is more evident in bands made of umbilical tape or silk rather than Silastic or Teflon bands. Types Due to the varying complications, different modifications of PAB have been developed to improve outcomes. Adjustable pulmonary artery banding has been available since 1972, allowing variable constriction. FloWatch (Leman Medical, Geneva, Switzerland: www.lemanmedical.com), an adjustable band, was created and has successfully been tested to overcome complications due to non-optimal sizing of the band. FloWatch is a wireless, battery-free, implantable device that allows the band size to be adjusted without the need for additional surgeries or other invasive procedures. The narrowing of the pulmonary artery can be controlled weeks or even months after the operation. Reports also show that the recovery period in patients that obtained the FloWatch device was faster and smoother in comparison to those that received the traditional PAB method. However FloWatch is only suitable for children with a body weight ranging from 3 kg to10kg. References Cardiac surgery