Search

Objective – Clinical research with the pressure-volume loop (PVL) methodology remains impeded by the invasive, time-consuming and costly nature of conductance technology. The various PVL-derived parameters, however, have perioperative potential. We aimed to develop an online application (the eMv PVLooper) allowing clinicians and/or researchers to construct ventricular PVLs by combining a right- or left sided ventricular (or arterial) pressure trace with 3D volumetric echo data. Design and method – First, using simulator derived data (Harvi software), we compared our eMv PVLooper reconstructed PVLs with the provided simulator PVLs. For each ventricle, three loops with diminishing volume states were simulated. All derived parameters were compared. Next, we used clinical data from 12 adult patients who underwent elective CABG, in which right ventricular datasets were collected using 3D TEE (Philips Epiq with X8-2t probe, 4-beat gated imaging) and a pulmonary artery catheter with RV sideport (Edwards VIP+ 5 lumen). All patients were in sinus rhythm. Data were recorded after anaesthetic induction in steady states in baseline, during raised legs, during sustained PEEP of 20cmH2O and after chest opening. 3D datasets were analysed using TomTec Arena 4D RV-Function software. We compared end-diastolic volume (EDV), stroke volume (SV), cardiac output (CO), arterial (Ea) and end-systolic (Ees) elastance and ventriculo-arterial coupling (VAC) between the four conditions with a Wilcoxon signed-rank test. Results – For the simulated data, all calculated parameters matched the simulator output (including Ea, Ees and VAC). In the clinical dataset, overall PVL creation feasibility was 85.4% (rising to 97.6% when combining three acquisitions for each condition). Comparisons with p-values (vs baseline) after Wilcoxon signed-rank test are provided in the figure. Heart rate remained stable between all conditions. During leg raise, end-diastolic (+36 ±23 %) and stroke volume (+32 ±27%) augmented, resulting in increased cardiac output (+34 ±33%). Arterial and end-systolic elastances remained stable, resulting in an unchanged VAC. PEEP resulted in diminished cardiac output (-28 ±26%) attributable to a drop in stroke volume (-17% ±30%). Arterial elastance was markedly increased (+126 ±80%), as opposed to the other conditions. Ees tended to rise (+29 % ±29%) but did not achieve statistical significance, resulting overall in a marked decrease in VAC (-39% ±17%). Chest opening resulted in minor effects. Most notably, right ventricular coupling dropped due to a lowering of Ees (-23% ±22%). Boxplots of output variables of PVL of twelve patients in the four conditions: baseline (black), leg raise (pink), sustained PEEP (blue) and open chest condition (green). P-values from Wilcoxon signed-rank versus baseline. Significance levels: *** (p<0.001), ** (p<0.01), * (p<0.05). – Our results suggest that expected physiologic responses could be reproduced using the eMv PVLooper, underscoring the potential of this methodology to advance the understanding and clinical application of pressure-volume frameworks in cardiovascular research and patient care. External validation after this observational setup is required. We wish to underscore that this methodology can also be applied to left sided measurements, notably with arterial pressure data (resulting in PV arcs, representing the systolic part of the PVL). [ABSTRACT FROM AUTHOR]

Left ventricular (LV) diastolic function predicts patient outcome in cardiac surgery. However, the intraoperative assessment of LV diastolic dysfunction (LVDD) poses challenges due to the load-dependency of most conventional echocardiographic parameters and the dynamic changes of loading conditions in the perioperative course of cardiac surgery. Moreover, LV diastolic function often changes because of the performed procedures and the required supportive interventions. Diastolic strain-based measurements assessed by intraoperative transesophageal echocardiography (TEE) showed to be less load-dependent, and to have strong correlation with LV relaxation, compliance and filling in coronary artery bypass grafting, but there are no reports about evaluation in aortic valve replacement (AVR) surgery. Therefore, we aimed to describe the changes of LV diastolic function assessed by myocardial strain as well as by conventional echocardiographic measurements and common grading algorithms in this patient population. Thirty adult patients scheduled for isolated surgical AVR were included into this prospective observational study. All included patients had preoperative preserved left and right ventricular function, without significant other heart valve disease, and an uneventful intraoperative course. TEE was performed intraoperatively after induction of anesthesia (T1), after termination of cardiopulmonary bypass (T2), and after sternal closure (T3) using General Electric Vivid E95 echocardiography machines and 6VT-D TEE probes. All measurements were performed in stable hemodynamics, in sinus rhythm or atrial pacing, and without significant vasoactive support. EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of strain-based measurements of peak longitudinal strain rate during isovolumetric relaxation (SR-IVR), and during early (SR-E) and late (SR-A) LV filling. Assessment of conventional echocardiographic parameters enclosed trans-mitral doppler measures of early (E) and late (A) LV filling, as well as of lateral tissue doppler velocity assessed during early (e´) and late (a´) LV filling. LVDD was graded according to current recommendations and additionally by a strain-based approach. Diastolic strain analysis and grading of LV diastolic function via myocardial strain were feasible in 27 (90%) patients at all timepoints of assessment. LV diastolic function improved significantly after AVR as measured by SR-IVR (T1 v T3, 0.31 s-1 (IQR 0.22; 0.38) v 0.4 s-1 (IQR 0.33; 0.43); p=0.01), SR-E (T1 v T3, 1.13 s-1 (IQR 0.89;1.28) v 1.35 s-1 (IQR 1.10;1.52); p=0.035), and E/SR-IVR (T1 v T3, 2.2m (IQR 1.7;2.8) v 1.6m (IQR 1.3;2.2); p=0.013). Moreover, there was a significant reduction of patients with LVDD grad 2 and 3 as measured by the strain-based algorithm (T1 v T3, n=14 v n= 6; p=0.026). In contrast, conventional echocardiographic measurements and grading algorithms were not able to detect these changes in the same period. In conclusion, evaluation of intraoperative diastolic strain-based measurements and strain-based LVDD grading were feasible in our group of selected AVR patients. LV diastolic function improved after AVR as measured by myocardial strain, however, was not detected by conventional echocardiographic parameters and grading algorithms. Therefore, diastolic myocardial strain might be more sensitive in detecting LVDD by TEE in the perioperative setting with its dynamic changes of loading conditions. [ABSTRACT FROM AUTHOR]

Non-invasive right ventricular (RV) myocardial work (MW) is a novel echocardiographic technique evaluating cardiac mechanics, contractility, and energetics beyond conventional echocardiographic measurements. This technique is an advancement of myocardial strain analysis and combines RV strain with loading conditions. It correlates well with invasively measured myocardial work and with myocardial oxygen consumption. RV MW is independent of afterload and seems best suitable for perioperative assessment of RV function. However, this technique has not yet been well described in the perioperative setting. Therefore, we aimed to evaluate this innovative method in the perioperative course of left ventricular assist device (LVAD) implantation and compare it to conventional echocardiographic and hemodynamic measurements. We conducted a retrospective analysis of all 78 patients that underwent LVAD implantation from January 2014 to January 2024 at our institution. 32 patients had echocardiographic images performed with echocardiographic machines and software appropriate for RV MW analysis, of whom ten patients had complete pre- and postoperative images required for estimation of RV MW indices. Transthoracic echocardiography (TTE) was completed during the preoperative evaluation (T1) and before discharge from hospital (T2), without any vasoactive support under stable hemodynamic conditions. EchoPAC v204 software (GE Vingmed Ultrasound AS, Norway) was used for analysis of RV global work index (GWI), RV global constructive work (GCW), RV global wasted work (GWW), RV global work efficiency (GWE), RV global longitudinal strain (GLS), RV free-wall strain (FWS), longitudinal strain of the interventricular septum (IVS), RV fractional area change (FAC), and tricuspid annular systolic excursion (TAPSE). Moreover, RV filling pressures were estimated echocardiographically to evaluate loading conditions. RV contractile pattern changed significantly in our patient population through the perioperative course of LVAD implantation [T1 v T2]. RV free-wall longitudinal function decreased (FWS, -8.2% (IQR -5.7;-10.9) v -5.9% (IQR -5.2;-8.1), p=0.04; TAPSE, 16mm (IQR 14;20) v 9mm (IQR 8;11), p<0.01), while septal contribution and global RV function improved (IVS, -2.2% (IQR -1.5;-3.9) v -5.0% (IQR -3;-9), p=0.04; FAC, 25% (IQR 18;32) v 36% (24;43), p=0.03). RV MW analysis showed a reduction of RV effective (GWI, 212mmHg% (IQR 128;266) v 96mmHg% (IQR 63;150), p=0.02; GCW, 331mmHg% (IQR 263;476) v 198mmHg% (IQR 136;274), p<0.01) and ineffective myocardial work (GWW, 171mmHg% (IQR 102;243) v 98mmHg% (IQR 48;153), p=0.04), suggesting a reduction of RV myocardial oxygen consumption after device implantation. RV filling pressures declined, while RV efficiency remained unchanged (GWE, 69% (IQR 37;78) v 64% (IQR (61;78), p=0.26) in the same period. In conclusion, there was a change of RV contractile pattern in our patient population after LVAD implantation with a reduction of RV longitudinal function, which was compensated by an increase of RV circumferential contraction and interventricular septum contribution that even improved global RV function. Assessment of RV MW indices showed decreased RV myocardial workload after device implantation, suggesting a reduction of RV myocardial oxygen consumption in our patient population. RV MW is an evolving non-invasive technique providing deeper insights into perioperative RV energetics and could support individualized decision making in cardiac surgery patients. [ABSTRACT FROM AUTHOR]