Hemodynamics during and immediately after the surgical creation of a supravalvular pulmonary stenosis in pigs.

The surgical creation of a supravalvular pulmonary stenosis (PS) adequate to prepare the left ventricle (LV) for anatomic correction in cases of simple transposition of the great arteries (TGA) is difficult. To gain more information on the hemodynamic changes immediately following PS of various degrees, pressures (P) in the right atrium (RA), right ventricle (RV), pulmonary artery (PA) and left ventricle (LV) as well as pulmonary flow (F) were monitored 40 minutes (30 to 50 minutes after PS (n = 15) in 10 open chested pigs (mean weight: 20.7 kg). Hemodynamic changes can be separated into an adaptation phase (AP) with an "overshoot" response of most hemodynamic parameters and a stable phase (SP) without further changes, reached after 6.5 minutes (1 to 18 minutes). This pattern was independent of the degree of PS (increase of RV Pmax: 13 to 39 mmHg). Maximal changes (p less than 0.01) during AP included: RV Pmax: +25 +/- 9 mmHg, RV EDP: +6 +/- 3 mmHg, RV dp/dt max: +315 +/- 208 mmHg/sec, LV Pmax: -43 +/- 24 mmHg, PA max. syst. flow: -0.3 +/- 0.15 ml/sec, CO: -0.45 +/- 0.3 l/min. During SP, LV Pmax and PA Pmean were normal. RV EDP and RA Pmean had decreased (p less than 0.01) but remained elevated as compared to the control values (p less than 0.01). The right ventricular maximal pressure had decreased 30% but remained elevated compared to control values (p less than 0.01). A change of RV Pmax during SP correlated (r = 0.93) with the maximal change of RV Pmax during AP.(ABSTRACT TRUNCATED AT 250 WORDS)