Effects of acute decrease in systemic afterload on accuracy of Doppler-derived left ventricular rate of pressure rise measurement in anesthetized patients

Abstract

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 ΔP/Δt) 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 ΔP/Δt 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 ΔP/Δt (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 ΔP/Δt does not overestimate LV contractility in the presence of an acute decrease in systemic afterload. (J Am Soc Echocardiogr 2001;14:1161-5.)