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Effects of acute decrease in systemic afterload on accuracy of Doppler-derived left ventricular rate of pressure rise
S M Broka1, P E Dubois, J Jamart
1Department of Anesthesiology, University Clinics U.C.L. of Mont-Godinne, Yvoir, Belgium. broka@anes.ucl.ac.be
Objectives:
This study was designed to describe exactly the effects of acute decrease in systemic afterload on the accuracy of Doppler-derived left ventricular rate of pressure rise (LV DeltaP/Delta(t)) measurements compared with other routinely used indices of systolic function.
Methods:
Twelve patients scheduled for coronary artery bypass grafting were studied. After induction of anesthesia (T0), afterload was modified by incremental administrations of nicardipine (T1-4). At each step of the procedure, thermodilution-derived cardiac index, left ventricular (LV) fractional area change, and LV DeltaP/Delta(t) were measured, and systemic vascular resistances were calculated.
Results:
During the procedure, the systemic vascular resistances decrease averaged 13.4%. Systemic vascular resistances were correlated with LV DeltaP/Delta(t) (r = 0.843, P =.003) but inversely correlated with cardiac index (r = -0.782, P =.005) and LV fractional area change (r = -0.887, P =.003).
Conclusion:
In conclusion, and inversely to cardiac index or LV fractional area change, LV DeltaP/Delta(t) does not overestimate LV contractility in the presence of an acute decrease in systemic afterload.