Pulmonary wave intensity analysis to assess ventriculo-arterial interactions in cardiogenic shock

Figures

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  Figure 1. Study flow diagram. Figure caption: Study flowchart outlining patient screening and enrollment for pulmonary WIA. Over a 12-month period, patients undergoing diagnostic RHC were screened. Ten control subjects were recruited from the post-heart transplant population and were required to be >6 months post-transplant, >18 years of age, and have normal pulmonary artery hemodynamics. Nineteen patients with CS were enrolled based on low cardiac index (CI <2.2 L/min/m²) and additional markers of hypoperfusion or organ dysfunction, with exclusion of those mechanically ventilated or recently resuscitated. CS subjects underwent implantation of either an IABP or Impella 5.5 device. All patients underwent simultaneous RHC and transthoracic Doppler TTE for WIA. Control subjects had a single recording, while CS patients were assessed pre- and post-MCS device implantation. A total of 29 subjects had complete paired pressure-flow datasets available for analysis. Abbreviations: ALT, Alanine Aminotransferase; CI, Cardiac Index; CS, Cardiogenic Shock; IABP, Intra-Aortic Balloon Pump; Impella 5.5, Percutaneous Left Ventricular Assist Device (Abiomed Impella 5.5); MCS, Mechanical Circulatory Support;…

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  Figure 2. Representative pulmonary wave intensity analyses. Figure caption: Each panel displays wave intensity profiles derived from pressure-flow data over a single cardiac cycle, showing forward compression waves (FCW, blue), forward decompression waves (FDW, green), backward compression waves (BCW, red), and backward decompression waves (BDW, purple). The timing of peak BCW (red dotted line) and end of the cardiac cycle (black dotted line) are marked. All plots are normalized to the same x- (time) and y-(wave intensity) axes for comparison. 1a: pulmonary WIA during dobutamine infusion at 7.5 µg/kg/min in a patient with CS. This high-dose inotropic support is associated with increased forward wave intensity, a moderate increase in backward wave intensity, but no increase in reflected wave speed. 1b: pulmonary WIA during milrinone infusion at 0.375 µg/kg/min in a patient with CS. There is a minimal increase in forward-traveling wave intensity with salutatory effects on the backward-traveling wave intensity. There is a relative reduction in reflected wave speed, likely due to peripheral vasodilation. 1c: pulmonary WIA during sodium nitroprusside infusion at 1.25 µg/kg/min. There is minimal…

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  Figure 3. Box-and-Whisker plots. Figure caption: Box-and-whisker plots demonstrate forward compression wave (FCW), forward decompression wave (FDW), backward compression wave (BCW), backward decompression wave (BDW), time-to-peak BCW, reflection index (RI), net wave intensity (NWI), and wave speed in 3 groups: healthy controls (0), patients with cardiogenic shock (CS; 1), and those supported with mechanical circulatory support (MCS; 2) using either intra-aortic balloon pump (IABP) or Impella 5.5. Significant pairwise differences were observed between controls and CS for BDW (p < 0.01) and wave speed (p < 0.01), and between CS and MCS for time-to-peak BCW (p = 0.048). Significant pairwise differences between controls and MCS subjects in FCW (p = 0.02), FDW (p < 0.01), BDW (p < 0.01), and wave speed (p = 0.03) were observed. Abbreviations: BCW, backward compression wave; BDW, backward decompression wave; CS, cardiogenic shock; FCW, forward compression wave; FDW, forward decompression wave; IABP, Intra-Aortic Balloon Pump; Impella, Percutaneous Left Ventricular Assist Device (Abiomed Impella 5.5); MCS, mechanical circulatory support; NWI, net wave intensity; WIA, wave intensity analysis.

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  Figure 4. Spaghetti plots pre- and post- MCS intervention. 4 (top): Pre- and post-IABP support changes in wave intensity parameters among patients with CS. Forward wave magnitudes (FCW, FDW) increased in most patients, while backward wave magnitudes (BCW, BDW) remained largely unchanged, resulting in a consistent reduction in reflection index (RI). There was no significant change in time-to-peak BCW or wave speed, suggesting preserved timing and stiffness characteristics. A general upward shift in net wave intensity (NWI) was observed, indicating improved overall wave energy balance and potentially more favorable ventriculo-arterial coupling with IABP support. 4 (bottom): Pre- and post-Impella 5.5support changes in wave intensity parameters among patients with CS. Following Impella 5.5 insertion, FCW and FDW magnitudes increased in several patients, though a subset showed either no change or a decrease. BCW timing was consistently delayed post-support, indicating later arrival of reflected waves. Backward wave magnitudes (BDW and BCW) generally became less negative, reflecting a reduction in wave reflection severity, although exceptions were noted. These changes were associated with a…