Systolic time intervals and longitudinal left ventricular function as simplified surrogates of ventriculo-arterial coupling in acute cardiac care
D Guz, R Z Filipescu, O D Geavlete, R I Radu, O ChioncelAbstract
Background
Left ventricular (LV) ventricular-arterial coupling (VAC) refers to the ratio of afterload (effective arterial elastance-Ea) to contractility (end-systolic elastance-Ees) as an integrated marker of cardiac performance. Approximation of the Ees by single-beat surrogates is strongly correlated to invasive measurements. However, single-beat formulas are underused in clinical practice, probably due to their complexity, rendering the estimate sensitive to small measurement inaccuracies.
Objectives
We sought to evaluate a simplified surrogate of VAC, PEP/(MAPSE×MAP), integrating systolic timing (pre-ejection period, PEP), longitudinal ventricular function (mitral annular plane systolic excursion, MAPSE), and arterial load (mean arterial pressure, MAP), and to compare its performance against non-invasively derived Ea/Ees estimated using the Chen single-beat method.
Methods
We conducted an observational echocardiographic study including consecutive patients presenting to the cardiology emergency department of a tertiary care hospital during on-call periods. VAC was estimated non-invasively as Ea/Ees, where Ea was derived as 0.9×systolic blood pressure/stroke volume and Ees was computed using the Chen single-beat method. PEP/(MAPSE×MAP) was calculated from standard echocardiographic and haemodynamic measurements. Data distribution was assessed with the Shapiro-Wilk test. Associations between systolic time intervals, pressure, volumes, and Chen's formula were evaluated using Pearson or Spearman correlation as appropriate. Ventriculo-arterial uncoupling was predefined as Ea/Ees-Chen≥ 1.3. Discrimination of uncoupling by the surrogate was assessed using receiver operating characteristic (ROC) analysis.
Results
Thirty-nine patients were analyzed (mean age 58 ± 15 years; 59% male). Most patients were at risk of heart failure (ACC/AHA stage A, 66%), while 34% had established heart failure (stage C). PEP/(MAPSE×MAP) demonstrated the most significant monotonic association with Ea/Ees (Spearman r= 0.81; p< 0.0001; Figure 1). In ROC analysis, PEP/(MAPSE×MAP) showed excellent discrimination for the identification of ventriculo–arterial uncoupling, with an optimal cutoff value of 0.0724 (AUC 0.90; p< 0.0001; Sensitivity 1.0; Specificity 0.84; Figure 2).
Conclusion
In a real-world emergency cardiology cohort, a simplified index combining systolic timing, longitudinal ventricular shortening, and arterial load was closely associated with non-invasively estimated ventriculo–arterial coupling and effectively identified ventriculo-arterial uncoupling. These findings support the physiological relevance of systolic time intervals and suggest that PEP/(MAPSE×MAP) may represent a pragmatic surrogate of VAC for rapid bedside haemodynamic assessment, warranting validation in larger heart failure populations.Figure 1For image description, please refer to the figure legend and surrounding text.Figure 2For image description, please refer to the figure legend and surrounding text.