Influence of changes in ventricular systolic function and loading conditions on pulse contour analysis-derived femoral dP/dtmax

Abstract

Background Femoral d P /d t max (maximum rate of the arterial pressure increase during systole) measured by pulse contour analysis has been proposed as a surrogate of left ventricular (LV) d P /d t max and as an estimator of LV systolic function. However, femoral d P /d t max may be influenced by LV loading conditions. In this study, we evaluated the impact of variations of LV systolic function, preload and afterload on femoral d P /d t max in critically ill patients with cardiovascular failure to ascertain its reliability as a marker of LV systolic function. Results We performed a prospective observational study to evaluate changes in femoral d P /d t max , thermodilution-derived variables (PiCCO2—Pulsion Medical Systems, Feldkirchen, Germany) and LV ejection fraction (LVEF) measured by transthoracic echocardiography during variations in dobutamine and norepinephrine doses and during volume expansion (VE) and passive leg raising (PLR). Correlations with arterial pulse and systolic pressure, effective arterial elastance, total arterial compliance and LVEF were also evaluated. In absolute values, femoral d P /d t max deviated from baseline by 21% (201 ± 297 mmHg/s; p = 0.013) following variations in dobutamine dose ( n = 17) and by 15% (177 ± 135 mmHg/s; p < 0.001) following norepinephrine dose changes ( n = 29). Femoral d P /d t max remained unchanged after VE and PLR ( n = 24). Changes in femoral d P /d t max were strongly correlated with changes in pulse pressure and systolic arterial pressure during dobutamine dose changes ( R = 0.942 and 0.897, respectively), norepinephrine changes ( R = 0.977 and 0.941, respectively) and VE or PLR ( R = 0.924 and 0.897, respectively) ( p < 0.05 in all cases). Changes in femoral d P /d t max were correlated with changes in LVEF ( R = 0.527) during dobutamine dose variations but also with effective arterial elastance and total arterial compliance in the norepinephrine group ( R = 0.638 and R = − 0.689) ( p < 0.05 in all cases). Conclusions Pulse co...

When one cannot see the forest for the trees: femoral dP/dtmax, LVEF and pulse pressure in critically ill patients

“…Our colleagues challenge the use of LV ejection fraction (LVEF) as a marker of LV systolic function and its comparison with femoral d P /d t max to assess the reliability of the femoral d P /d t max to track changes in LV contractility [1]. We entirely agree that LVEF is not a pure marker of LV contractility, as widely documented by others [2], and as clearly acknowledged in the discussion section of our article [3]. Furthermore, we agree that the invasive measure, LV end-systolic elastance (Ees), is the gold standard methodology to estimate LV contractility, but we were unable to measure it for ethical and technical reasons.…”

“…Furthermore, we agree that the invasive measure, LV end-systolic elastance (Ees), is the gold standard methodology to estimate LV contractility, but we were unable to measure it for ethical and technical reasons. In our paper [3], we presented LVEF data, as is commonly done in similar studies, but in contrast to the inference of our colleagues’ letter [1], our conclusion was not based upon LVEF results.…”

“…Interestingly, Sharman et al have also documented strong associations between radial d P /d t max and brachial PP in various populations of non-critically ill patients [4, 5]. Since PP is mainly influenced by arterial stiffness and stroke volume, and given the fact that PP explained > 80% of the variance of femoral d P /d t max , we concluded that femoral d P /d t max was mainly influenced by pulsatile arterial load [3]. These findings suggest that femoral d P /d t max is highly sensitive to changes in loading conditions, especially afterload, and thus may not be directly interchangeable with LV contractility.…”

“…In our study [3], we measured femoral d P /d t max by pulse contour analysis before and after varying, LV systolic function (dobutamine infusion), preload (volume expansion and passive leg-raising) and afterload (norepinephrine) in 19 critically ill patients with cardiovascular failure [3]. Femoral d P /d t max changed, not only in response to dobutamine infusion, but also following changes in cardiac loading, particularly following changes in afterload induced by variations in norepinephrine dose.…”

Assessing left ventricular systolic function with ejection fraction: using a double-edged knife as a hammer

“…We have read with interest the paper about the potential limitations of arterial d P /d t max for assessing left ventricular (LV) contractility [1]. In this study, the authors aimed to evaluate the performance of femoral d P /d t max from tracking changes in LV systolic function during different therapeutic interventions.…”