The Journal of Thoracic and Cardiovascular Surgery, Vol 90, 404-409, Copyright © 1985 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Acute control of pulmonary regurgitation with a balloon "valve". An experimental investigation
LG Siwek, RE Applebaum, M Jones and RE Clark
Operations for certain congenital cardiac lesions can produce pulmonary
regurgitation. Pulmonary regurgitation contributes to right ventricular
dysfunction, which may cause early postoperative morbidity and mortality.
To ameliorate the problems of pulmonary regurgitation during the early
postoperative period, we evaluated a method for its acute control. Complete
pulmonary valvectomy was performed utilizing inflow occlusion in eight
sheep. A catheter with a 15 ml spherical balloon was positioned in the
pulmonary arterial trunk; its inflation and deflation were regulated by an
intra-aortic balloon pump unit. Blood flow from the pulmonary arterial
trunk and forward and regurgitant fraction were determined from
electromagnetic flow transducer recordings. The regurgitant fraction with
uncontrolled pulmonary regurgitation was 38% +/- 3% (forward flow = 42 +/-
5 ml/beat and regurgitant flow = 16 +/- 2 ml/beat). Inflation of the
balloon during diastole was timed to completely eliminate pulmonary
regurgitation. This balloon control of pulmonary regurgitation increased
pulmonary arterial diastolic pressure from 12 +/- 1 to 17 +/- 1 mm Hg (p
less than 0.0001) and decreased pulmonary arterial systolic pressure from
31 +/- 3 to 27 +/- 1 mm Hg (p = 0.06). Pulmonary arterial pulse pressure
decreased from 19 +/- 3 to 9 +/- 1 mm Hg (p less than 0.003). Elimination
of pulmonary regurgitation decreased right ventricular stroke volume (25
+/- 3 versus 42 +/- 5 ml/beat, p less than 0.0002) and resulted in a 46%
reduction in right ventricular stroke work (5.0 +/- 0.6 versus 9.4 +/- 1.0
gm-m/beat, p less than 0.001) with no change in net forward pulmonary
artery flow. Thus, acute pulmonary regurgitation can be controlled and this
control improves overall hemodynamic status and decreases right ventricular
work.