Evidence for palliative enlargement of the right ventricular outflow tract in severe tetralogy of Fallot

Abstract

In a very severe form of TOF, palliative right ventricular outflow tract construction may provide the potential for complete repair. In the presented high-risk patient group, mortality was not related to the hypoplastic pulmonary arteries. Obviously, all patients need pulmonary valve implantation in the long run.

Stenting of the right ventricular outflow tract in the symptomatic infant with tetralogy of Fallot

“…Pulmonary arteries may be intrinsically diminutive with limited potential for growth or small vessel diameters may be secondary to decreased flow accompanying RVOT obstruction 4 11. The latter is demonstrated by increase in pulmonary artery dimensions after manoeuvres to augment pulmonary blood flow including surgical shunts, RVOT balloon dilation or stenting as in our series 4 5 7 11 16 24.…”

“…These risk factors include low weight, prematurity, young age (<3 months), unfavourable pulmonary arterial anatomy, abnormal coronary distribution and critical preoperative condition 1 – 3. Palliative procedures include surgical right ventricular outflow tract (RVOT) enlargement or conduit, aortopulmonary shunt, stenting of the arterial duct and balloon pulmonary valvuloplasty 4 – 10. While primary repair can and has been performed in these patients, it is associated with increased morbidity 1 11…”

Pulmonary Segmental Artery Ratio An Alternative to the Pulmonary Artery Index in Patients With Tetralogy of Fallot

“…[8][9][10][11][12] An important physiologic component of a favorable outcome is the postrepair peak right ventricular pressure, which may depend greatly upon the pulmonary arterial and aorta-pulmonary collateral morphology, as well as the type of repair performed. [4][5][6][7][8] In the present study, low and moderate risk patients were included while high risk patients with a PSAR < 0.50 were excluded. Therefore, the postrepair peak right ventricular pressures were very similar in the 2 groups.…”

“…The morphology and physiology of the pulmonary arteries are 2 main factors used to determine these ratios and indexes because the distribution, size of the pulmonary arteries, and efficiency of the pulmonary circulation are critical factors for successful surgery. 4,5,8,11,12) The McGoon ratio, which is the combined branch pulmonary arterial diameters divided by the descending aorta diameter, and the Nakata index, which is the combined cross-sectional area of the branch pulmonary arteries per square meter, are used to determine if the branch pulmonary arteries are large enough to permit corrective surgery. 12,17) Like the Mcgoon and Nakata indexes, smaller PSAR values are related to poor postsurgical outcomes, although in some cases PSAR and the PA index may not always be correlated (Figure 2).…”

“…An important physiologic component of a favorable outcome is the postrepair peak right ventricular pressure, which may depend greatly upon the pulmonary arterial and aorta-pulmonary collateral morphology as well as the type of repair procedure. 4) Thus, the ultimate goals are to decide whether to choose a single stage correction in early infancy or not and how to determine the timing and type of operation for these patients.…”