Perioperative clinical utility of myocardial deformation imaging: a narrative review

Optimal Global Longitudinal Strain Thresholds for Pediatric Heart Surgery: Insights from a University Hospital

Congenital heart diseases impact millions annually, with pediatric care lacking suitable risk assessment tools. This research seeks to illuminate the association between the global longitudinal strain (GLS) and the subsequent impact on postoperative outcomes, contributing to a deeper understanding of its predictive value in the pediatric population affected by congenital heart diseases. An observational, analytic, longitudinal, and prospective study was conducted from May 2022 to May 2023, including all patients under 18 undergoing heart surgery with cardiopulmonary bypass (CBP). Patients not classifiable within the Risk Adjustment for Congenital Heart Surgery were excluded. Using transesophageal echocardiography, GLS was measured pre- and post-CPB. Receiver operating characteristic curve analysis determined GLS cut-off points for 30-day mortality risk, using Youden's method for optimal sensitivity and specificity. Bivariate and multivariate analysis identified the relationships between clinical variables. Eighty-nine patients undergoing congenital heart surgery were included. Fifteen deaths occurred. The area under the curve (AUC) for each GLS classification (pre, post, index) demonstrated effective discriminatory capacity (> 0.70) in predicting 30-day mortality. Pre-CBP GLS showed the strongest predictive power (AUC 0.833, IQR: 0.731 - 0.936) with a cut-off point of 12. Values lower than the cut-off point of pre-CPB GLS correlated with increased vasoactive-inotropic Scores and longer mechanical ventilation. GLS measurement is a reproducible method for assessing ventricular function in pediatric heart surgery, showing potential as a prognostic tool. This study marks the initial effort to establish cut-off points for preoperative GLS, postoperative GLS, and the strain index.

Hyperoxia-induced deterioration of diastolic function in anaesthetised patients with coronary artery disease - Randomised crossover trial

Background

There are no current recommendations for oxygen titration in patients with stable coronary artery disease. This study investigates the effect of iatrogenic hyperoxia on cardiac function in patients with coronary artery disease undergoing general anaesthesia.

Methods

Patients scheduled for elective coronary artery bypass graft surgery were prospectively recruited into this randomised crossover clinical trial. All patients were exposed to inspired oxygen fractions of 0.3 (normoxaemia) and 0.8 (hyperoxia) in randomised order. A transoesophageal echocardiographic imaging protocol was performed during each exposure. Primary analysis investigated changes in 3D peak strain, whereas secondary analyses investigated other systolic and diastolic responses.

Results

There was no statistical difference in systolic function between normoxaemia and hyperoxia. However, the response in systolic function to hyperoxia was dependent on ventricular function at normoxaemia. Patients with a normoxaemic left ventricular (LV) global longitudinal strain (GLS) poorer than the derived cut-off (>-15.4%) improved with hyperoxia (P<0.01), whereas in patients with normoxaemic LV-GLS <-15.4%, LV-GLS worsened with transition to hyperoxia (P<0.01). The same was seen for right ventricular GLS with a cut-off at -24.1%. Diastolic function worsened during hyperoxia indicated by a significant increase of averaged E/e' (8.6 [2.6]. vs 8.2 [2.4], P=0.01) and E/A ratio (1.4 (0.4) vs 1.3 (0.4), P=0.01).

Conclusions

Although the response of biventricular systolic variables is dependent on systolic function at normoxaemia, diastolic function consistently worsens under hyperoxia. In coronary artery disease, intraoperative strain analysis may offer guidance for oxygen titration.

Clinical trial registration

NCT04424433.

Normal range of intraoperative three-dimensionally derived right ventricular free-wall strain in coronary artery bypass surgery patients

BACKGROUND

Data on intraoperative three-dimensionally derived right ventricular free-wall strain (3D-RV FWS) is sparse.

OBJECTIVES

We sought to evaluate the normal range of intraoperative 3D-RV FWS in patients scheduled for coronary artery bypass graft (CABG) surgery and compared to conventional echocardiographic parameters. Prospective observational study.

METHODS

A total of 150 patients with preserved left and right ventricular (RV) function and sinus rhythm, without significant heart valve disease or pulmonary hypertension undergoing isolated on-pump CABG surgery, with an uneventful, complication-free intraoperative course. 3D-RV FWS analysis and conventional echocardiographic assessment of RV function were performed intraoperatively in anesthetized and ventilated patients using transesophageal echocardiography (TEE). TomTec 4D RV-Function 2.0 software for assessment of 3D-RV FWS and three-dimensional right ventricular ejection fraction (3D-RV EF). Philips QLAB 10.8 was used to evaluate tissue velocity of the tricuspid annulus (RV S´), tricuspid annular systolic excursion (TAPSE), and RV fractional area change (FAC). All echocardiographic measurements were performed under stable hemodynamic conditions and predefined fluid management without any vasoactive support or pacing. The prospective observational study was performed in a single university hospital setting.

RESULTS

Assessment of 3D-RV FWS was feasible in 95% of patients. No included patient experienced any serious perioperative complication. In our group of patients, median values with interquartile range (IQR) for 3D-RV FWS and 3D-RV EF were -25.2 (IQR -29.9 to -21.8) and 46.3% (IQR 41.0%-50.1%), respectively. RV FAC, RV S´, and TAPSE accounted for 39.7% (IQR 34.5%-44.4%), 14.8 cm/s (IQR 11.8-19.0 cm/s), and 22 mm (IQR 20-25 mm). The normal range (2.5% to 97.5% percentile) for 3D-RV FWS was -37.1 to -12.8. There was no relevant correlation of 3D-RV FWS to postoperative outcome in this group of CABG patients.

CONCLUSION

We present distribution values for intraoperative 3D-RV FWS and conventional parameters of RV function assessment in a healthy on-pump CABG patient population without serious perioperative complications. We observed no correlations of these parameters with any of the outcome parameters considered. Therefore, we consider these values to be intraoperative TEE-assessed normal values, which can be expected in on-pump CABG patients.

Impaired Speckle-Tracking-Derived Left Ventricular Longitudinal Strain Is Associated with Transposition of Great Arteries in Neonates: A Single-Center Study

The transposition of great arteries (TGA) is one of the most frequent and severe congenital heart diseases. After newborn stabilization and while pending surgical correction, echocardiographic monitoring with a careful evaluation of left ventricle (LV) performance is warranted. In this study, our objectives were (i) to compare myocardial function, assessed via speckle-tracking echocardiography, between neonates with TGA and neonates without TGA and (ii) to identify a strain parameter with a good discriminatory ability for TGA. We conducted a retrospective, single-center study. A total of 90 neonates were examined, of whom 66 were included (16 comprised the TGA group and 50 comprised the control group). The results of a bivariate analysis showed that classic echocardiography parameters displayed no significant differences between the two studied groups (p = 0.785 for EF, p = 0.286 for MAPSE and p = 0.315 for TAPSE). We found a statistically significant difference between the two groups for the mean values of the LVpGLS parameter (adjusted p = 0.0047), with impaired LV myocardium function being observed in the TGA group after adjusting for other covariates. Regarding segmental strain, the mean medial and apical inter-ventricular septum strain values were found to be significantly lower in the neonates with TGA than in the controls (95% CI for difference in means: [-6.45, -0.65], [-8.56, -1.97]). The results of an ROC analysis showed that LVpGLS had a significant ability to differentiate between neonates with TGA and controls (AUC = 0.712, 95% CI: [0.52, 0.903], p = 0.011). In conclusion, LVpGLS is a parameter with a significant discriminatory ability for LV dysfunction, and it is useful in the evaluation of ventricular myocardial function in newborns with TGA.

Current and novel echocardiographic assessment of left ventricular systolic function in aortic stenosis-A comprehensive review

Aortic stenosis (AS) is a complex and progressive condition that can significantly reduce the quality of life and increase the incidence of premature mortality. Transthoracic echocardiography (TTE) is the gold standard imaging modality for the assessment of AS severity. While left ventricular ejection fraction (LVEF) derived from TTE is a very well-understood parameter, limitations such as high inter and intra-observer variability, insensitivity to sub-clinical dysfunction, and influence of loading conditions make LVEF a complicated and unreliable parameter. Myocardial deformation imaging has been identified as a promising parameter for identifying subclinical left ventricular dysfunction, however, this parameter is still afterload dependent. Myocardial Work is a promising novel assessment technique that accounts for afterload by combining the use of myocardial deformation imaging and non-invasive blood pressure to provide a more comprehensive assessment of mechanics beyond LVEF. This review evaluates the evidence for various echocardiographic assessment parameters used to quantify left ventricular function including myocardial work in patients with AS.

A head-to-head comparison of fast-SENC and feature tracking to LV long axis strain for assessment of myocardial deformation in chest pain patients

BACKGROUND

Myocardial strain imaging has gained importance in cardiac magnetic resonance (CMR) imaging in recent years as an even more sensitive marker of early left ventricular dysfunction than left-ventricular ejection fraction (LVEF). fSENC (fast strain encoded imaging) and FT (feature tracking) both allow for reproducible assessment of myocardial strain. However, left-ventricular long axis strain (LVLAS) might enable an equally sensitive measurement of myocardial deformation as global longitudinal or circumferential strain in a more rapid and simple fashion.

METHODS

In this study we compared the diagnostic performance of fSENC, FT and LVLAS for identification of cardiac pathology (ACS, cardiac-non-ACS) in patients presenting with chest pain (initial hscTnT 5-52 ng/l). Patients were prospectively recruited from the chest pain unit in Heidelberg. The CMR scan was performed within 1 h after patient presentation. Analysis of LVLAS was compared to the GLS and GCS as measured by fSENC and FT.

RESULTS

In total 40 patients were recruited (ACS n = 6, cardiac-non-ACS n = 6, non-cardiac n = 28). LVLAS was comparable to fSENC for differentiation between healthy myocardium and myocardial dysfunction (GLS-fSENC AUC: 0.882; GCS-fSENC AUC: 0.899; LVLAS AUC: 0.771; GLS-FT AUC: 0.740; GCS-FT: 0.688), while FT-derived strain did not allow for differentiation between ACS and non-cardiac patients. There was significant variability between the three techniques. Intra- and inter-observer variability (OV) was excellent for fSENC and FT, while for LVLAS the agreement was lower and levels of variability higher (intra-OV: Pearson > 0.7, ICC > 0.8; inter-OV: Pearson > 0.65, ICC > 0.8; CoV > 25%).

CONCLUSIONS

While reproducibility was excellent for both FT and fSENC, it was only fSENC and the LVLAS which allowed for significant identification of myocardial dysfunction, even before LVEF, and therefore might be used as rapid supporting parameters for assessment of left-ventricular function.

[Intraoperative transesophageal echocardiography for emergency diagnostics in noncardiac surgery patients]

Due to the development of compact and mobile devices, transesophageal echocardiography (TEE) is now being used as one important point-of-care diagnostic method in emergency rooms, intensive care units and operating rooms. In the first part of this advanced training series, general aspects of the examination method and the procedure as well as indications and contraindications were outlined. In addition, an overview of application areas beyond cardiac surgery in which TEE can be used to monitor the patient or to assist with the operative procedure was provided. In the second part, the main findings during intraoperative TEE in the event of hemodynamic instability or unexplained hypoxemia are presented. A shortened emergency examination as proposed by Reeves et al. is outlined. The article concludes with an outlook on semiautomatic interpretation software and computer-aided image acquisition.

Perioperative Two-Dimensional Left Ventricular Global Longitudinal Strain in Coronary Artery Bypass Surgery: A Prospective Observational Pilot Study

OBJECTIVES

There are limited data on perioperative left ventricular strain. The authors aimed to describe the entire perioperative course of two-dimensional left ventricular global longitudinal strain in patients undergoing coronary artery bypass graft (CABG) surgery and compare to common parameters of LV function assessment.

DESIGN

Prospective observational study.

SETTING

Single university hospital.

PARTICIPANTS

Forty patients scheduled for isolated on-pump CABG surgery with preserved left and right ventricular function with an unremarkable, complication-free perioperative course.

INTERVENTIONS

Two-dimensional strain analysis and standard echocardiographic assessment of left ventricular function were performed pre- (T1) and postoperatively (T4) by transthoracic echocardiography (TTE) and intraoperatively pre- (T2) and poststernotomy (T3) by transesophageal echocardiography (TEE). Echocardiography was performed under stable hemodynamics and predefined fluid management, in sinus rhythm without any vasoactive support.

MEASUREMENTS AND MAIN RESULTS

Analysis of two-dimensional LV global longitudinal strain (2D-LV GLS) was performed using Tomtec 2D Cardiac Performance Analysis software. Philips QLAB 10.8 was used to analyze left ventricular ejection fraction (LV EF) and tissue velocity of the lateral mitral annulus (LV S ́). There were no significant differences (median with interquartile range [IQR]) after induction of anesthesia in values of LV EF and 2D-LV GLS (T1 v T2; 59% [IQR, 52 to 64] v 56% [IQR, 51.75 to 63] and -15.2 [IQR, -18.05 to -13.08] v -15.6 [IQR, -17.65 to -13.88]; both not significant [ns]), while LV S´ declined (T1 v T2, 7 cm/s [IQR, 5.25 to 8] v 5.25 cm/s [IQR, 4.6 to 6.83]; p < 0.001). Bland-Altman analysis for this comparison of 2D-LV GLS (T1 v T2) showed that bias was not significant between both techniques; however, there were limits of agreement. After sternotomy (T2 v T3) neither LV EF nor 2D-LV GLS or LV S´ declined. 2D-LV GLS deteriorated significantly after CABG (T1 v T4; -15.2 [IQR, -18.05 to -13.08] v -11.3 [IQR, -15.8 to -9.78]; p < 0.001). In contrast, LV EF and LV S´ did not change significantly in the perioperative interval (T1 v T4; 59% [IQR, 52 to 64] v 56% [IQR, 51.5 to 64.25] and 7 cm/s [IQR, 5.25 to 8] v 7 cm/s [IQR, 6 to 8]; both ns).

CONCLUSION

Values of 2D-LV GLS did not differ in awake, spontaneously breathing patients assessed by TTE and in anesthetized and ventilated patients with stable hemodynamics measured by TEE. 2D-LV GLS did not change after sternotomy; however, it declined significantly after on-pump CABG, while LV EF and LV S´ remained unchanged.

Acute changes of left ventricular function during surgical revascularization by 3D speckle tracking

BACKGROUND

Detecting early impact of coronary artery bypass grafting (CABG) on left ventricular (LV) function is important because such measures may contribute to meaningful improvement in clinical outcomes. We aimed to gain knowledge about acute changes of LV performance during surgical revascularization using three-dimensional speckle tracking echocardiography (3D STE).

METHODS

Thirty-five patients scheduled for CABG surgery who underwent intraoperative transesophageal echocardiography (TEE) were enrolled (mean age 68.9 ± 7.3 years). TEE was performed before and after surgery, as well as before and after grafting. 3D LV ejection fraction (LVEF), tissue motion annular displacement (TMAD) of the mitral valves, 3D global longitudinal strain (GLS), global circumferential strain (GCS), twist, and torsion were quantified. Regional longitudinal strain (LS) was calculated based on coronary perfusion territories in a 16-segment LV model.

RESULTS

Despite the absence of change in TMAD and 3D LVEF, 3D GLS (-18.6 ± 4.3% at baseline vs -16.0 ± 4.0% after surgery, P = .01) was significantly decreased, followed with no significant effect on GCS, twist, and torsion during surgery. 3D GLS correlated significantly with 3D LVEF (r between -0.34 and -0.51, P < .05 for all) under the whole operation. Territorial LS did not increase immediately after surgery.

CONCLUSION

3D speckle tracking imaging allows for detailed and direct evaluation of myocardial deformation, though impaired LV longitudinal function is still apparent immediately after surgery. GLS is more sensitive to an acute reduction in LV function than conventional parameters, which can be potentially useful for serial monitoring of functional recovery.

Perioperative Course of Three-Dimensional-Derived Right Ventricular Strain in Coronary Artery Bypass Surgery: A Prospective, Observational, Pilot Trial

OBJECTIVES

Few data exist on perioperative three-dimensional-derived right ventricular strain. The authors aimed to describe the perioperative course of three-dimensional-derived right ventricular strain in coronary artery bypass graft (CABG) surgery patients.

DESIGN

Prospective, observational, pilot trial.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 40 patients with preserved left ventricular and right ventricular (RV) function undergoing isolated on-pump CABG surgery.

INTERVENTIONS

Three-dimensional strain analysis and standard echocardiographic evaluation of RV function were performed preoperatively (T1) and postoperatively (T4) with transthoracic echocardiography (TTE) and intraoperatively before sternotomy (T2) and after sternotomy (T3) with transesophageal echocardiography (TEE). All echocardiographic measurements were performed under stable hemodynamic conditions and predefined fluid management without any vasoactive support.

MEASUREMENTS AND MAIN RESULTS

The measurements of three-dimensional-derived RV free-wall strain (3D-RV FWS) and RV ejection fraction were performed using TomTec 4D RV-Function 2.0 software. Philips QLAB 10.8 was used to analyze tissue velocity of the tricuspid annulus, tricuspid annular systolic excursion, and RV fractional area change. There were no significant differences (median [interquartile range {IQR}]) between preoperative TTE and intraoperative TEE measurements for 3D-RV FWS (T1 v T2: -22.35 [IQR -17.70 to -27.22] v -24.35 [IQR -20.63 to -29.88]; not significant). 3D-RV FWS remained unchanged after sternotomy (T2 v T3: -24.35 [IQR -20.63 to -29.88] v -23.75 [IQR -20.25 to -29.28]; not significant) but deteriorated significantly after CABG (T1 v T4: -22.35 [IQR -17.70 to -27.22] v -18.5 [IQR -16.90 to -21.65]; p = 0.004).

CONCLUSION

In patients undergoing on-pump CABG, 3D-RV FWS values for awake, spontaneously breathing patients measured with TTE and values assessed in patients under general anesthesia with TEE did not significantly differ. Three-dimensional RV FWS did not change after sternotomy but deteriorated after on-pump CABG.