Dopexamine unloads the impaired right ventricle better than iloprost, a prostacyclin analog, after coronary artery surgery.
OBJECTIVE
To evaluate the ventricle-unloading properties of dopexamine and iloprost and to compare their effects on right ventricular (RV) function and oxygen transport in patients with low RV ejection fraction (RVEF) after cardiac surgery.


METHODS
A prospective, randomized, double-blind, cross-over, clinical study.


METHODS
University hospital.


METHODS
Twenty patients with proximal total stenosis of the right coronary artery studied immediately after coronary artery surgery.


METHODS
Treatment drugs were administered in a random order in doses equipotent with respect to cardiac output response. Infusion rates were increased stepwise to induce a 25% increase in cardiac index. A washout period of 60 minutes was allowed between treatments.


RESULTS
Central hemodynamics, RV function assessed by the EF (fast-response thermodilution), end-systolic and end-diastolic volumes, and systemic oxygenation were measured before and after the first drug, after the washout period, and after the second drug. Central filling pressures remained constant during treatments. Both drugs decreased pulmonary vascular resistance index, but iloprost was more effective (p < 0.05). Iloprost decreased mean arterial and pulmonary artery pressure, which were unaffected by dopexamine. Dopexamine increased EF significantly more than iloprost (p < 0.001). End-systolic volume index decreased subsequent to dopexamine only (p < 0.001). Iloprost increased intrapulmonary shunt more than dopexamine (p < 0.001). Changes in oxygen delivery, consumption, and extraction were similar.


CONCLUSIONS
The findings suggest that dopexamine is more effective than iloprost for support and unloading of the postoperatively disturbed RV in terms of RVEF and end-systolic volume. The reduction of pulmonary vascular resistance after administration of iloprost without a decrease in end-systolic volume might not be considered a reduction of RV afterload. Iloprost increases the pulmonary shunt fraction, however, more than dopexamine, indicating a more prominent vasodilator effect.
Honkonen
E L
EL
Department of Anesthesia and Intensive Care, Tampere University Hospital, Finland.
Kaukinen
L
L
Kaukinen
S
S
Pehkonen
E J
EJ
Laippala
P
P
D002302:Cardiac Output / Q000187:drug effects; D001026:Coronary Artery Bypass; D018592:Cross-Over Studies; D004298:Dopamine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D016285:Iloprost / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011182:Postoperative Care; D011183:Postoperative Complications; D011446:Prospective Studies; D013318:Stroke Volume / Q000187:drug effects; D014665:Vasodilator Agents / Q000627:therapeutic use*; D016278:Ventricular Function, Right / Q000187:drug effects*
D014665:Vasodilator Agents; C046318:dopexamine; D016285:Iloprost; D010100:Oxygen; D004298:Dopamine