The Annals of Thoracic Surgery, Vol 39, 329-335, Copyright © 1985 by The Society of Thoracic Surgeons
The hemodynamic effects and mechanism of action of pulmonary artery balloon counterpulsation in the treatment of right ventricular failure during left heart bypass
PA Spence, RD Weisel, J Easdown, AK Jabr, V Yap and TA Salerno
The efficacy of pulmonary artery balloon counterpulsation (PABC) was
evaluated in improving right ventricular (RV) output during left heart
bypass for global cardiac failure. In 13 pigs, a 40-ml balloon was
positioned within a graft anastomosed to the pulmonary artery distal to the
pulmonary valve, and left heart bypass was instituted from the left atrium
to the carotid artery. Global myocardial failure was produced by an
infusion of propranolol (range, 25 to 78 mg). In this model, RV output
decreased despite volume loading to a right atrial pressure of 15 mm Hg and
atrioventricular sequential pacing at 100 beats per minute. Pulmonary
artery balloon counterpulsation increased both RV output (from 519 +/- 76
to 1,117 +/- 110 ml/min; p less than 0.01) and RV systolic stroke work
(from 1.3 +/- 0.4 to 2.3 +/- 0.6 gm-m; p less than 0.01). Right atrial
pressure decreased (from 15.5 +/- 0.9 to 10.7 +/- 1.0 mm Hg; p less than
0.01) in 8 of the pigs studied during RV failure. In 5 pigs, ventricular
fibrillation occurred without a stable model of RV failure, and there was
no cardiac output before or after counterpulsation. The mechanism of action
of PABC was studied by placing a flow probe around a large branch of the
right pulmonary artery. During RV failure, balloon inflation caused flow
through the pulmonary circulation, and ventricular systole resulted in
filling of the graft. During ventricular fibrillation, balloon inflation
and deflation produced only a to-and-fro movement of blood in the pulmonary
artery branch without net forward flow.(ABSTRACT TRUNCATED AT 250 WORDS)
