The Journal of Thoracic and Cardiovascular Surgery, Vol 77, 526-532, Copyright © 1979 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Decision-making in repair of tetralogy of Fallot based on intraoperative measurements of pulmonary arterial outflow tract
EH Blackstone, JW Kirklin and AD Pacifico
The equation that we proposed in this JOURNAL (1977), relating the
postrepair ratio between peak right ventricular pressure and peak left
ventricular pressure (PRV/LV) to the intraoperatively measured internal
diameter of the narrowest point in the pulmonary arterial outflow tract
(formerly called pulmonary "anulus"), performed well when prospectively
tested in 25 patients undergoing repair of the tetralogy of Fallot. The
observed PRV/LV in all 21 patients in whom no transannular patch was used
fell within the 70 percent confidence limits (1 standard deviation) of that
predicted from the measured diameter. A trivial difference (-0.03 +/- 0.069
PRV/LV units, P = 0.08) was found between predicted PRV/LV and that
observed after repair, with body surface area (BSA) used for normalization.
When the four additional patients who had secondary transannular patching
are included, or where the normalization was with weight, the differences
were not significant (p greater than 0.2). A slightly revised equation has
been devised using the combined data from our original group and the
patients used for prospective testing. This equation predicts with
reasonable accuracy (r = -0.69, p less than 0.0001) postrepair PRV/LV
without transannular patching from the intraoperatively measured diameter
of the pulmonary arterial outflow tract. We believe it is therefore helpful
in the operating room in making the important decision for or against using
transannular patching.
