General anesthesia and positive pressure ventilation suppress left and right ventricular myocardial shortening in patients without myocardial disease - a strain echocardiography study

Strain imaging as a prognostic indicator for complications in COVID-19 patients

The goal of this study was to determine the potential for right ventricular (RV) and left ventricular (LV) strain to predict cardiopulmonary complications of COVID-19. We identified 276 patients with COVID-19 who underwent transthoracic echocardiography within 30 days of COVID-19 diagnosis at our institution. Patients were excluded if they had a history of any primary outcomes before COVID-19 diagnosis or insufficient imaging. LV global longitudinal strain (GLS) and RV GLS were obtained using 2-dimensional speckle-tracking echocardiography. Primary outcomes were death, pulmonary embolism, congestive heart failure (CHF), cardiomyopathy, pulmonary fibrosis, pulmonary hypertension, acute respiratory distress syndrome (ARDS), and myocardial infarction (MI) occurring after COVID-19 diagnosis. In the final analysis of 163 patients, mean RV GLS and LV GLS were reduced, and 43.6% developed at least one primary outcome. There were significant differences in LV GLS distribution in terms of CHF, cardiomyopathy, and MI in bivariate analysis. However, LV GLS was not significantly associated with CHF after adjusting for LV ejection fraction and RV fractional area change, nor with MI after adjusting for troponin T. RV GLS was significantly associated with ARDS after adjusting for other variables. In the risk stratification of patients with COVID-19, strain imaging can provide incremental prognostic information, as worsened RV GLS is associated with the development of ARDS.

Haemodynamic effects of remifentanil during induction of general anaesthesia with propofol. A randomised trial

BACKGROUND

Remifentanil may have a dose-dependent haemodynamic effect during the induction of general anaesthesia combined with propofol. Our objective was to investigate whether systolic arterial blood pressure (SAP) was reduced to a greater extent when the remifentanil dose was increased.

METHODS

This randomised, double-blind, dose-controlled study was conducted at the Day Surgery Unit of Haugesund Hospital, Norway. Ninety-nine healthy women scheduled for gynaecological surgery were randomly allocated in a 1:1:1 ratio to receive remifentanil induction with a low, medium or high dose corresponding to maximum effect-site concentrations (Ce) of 2, 4 and 8 ng/mL. The induction dose of propofol was 1.8 mg/kg, with a Ce of 2.9 μg/mL. Anaesthesia was induced using target-controlled infusion. After 150 s of sedation, a bolus of remifentanil and propofol was administered. Baseline was defined as 55-5 s before the bolus dose, and the total observation time was 450 s. We used beat-to-beat haemodynamic monitoring with LiDCOplus. The primary outcome variable was the maximum decrease in SAP within 5 min after bolus administration of remifentanil and propofol. Absolute and relative changes from baseline to minimal values and the area under the curve (AUC) were used as effect measures. Comparisons of groups were performed using analysis of variance (ANOVA).

RESULTS

Median remifentanil doses were 0.75, 1.5 and 3.0 μg/kg in the low-, medium- and high-dose groups, respectively. The absolute changes (mean ± standard deviation) in SAP in the low-, medium- and high-dose groups of remifentanil were -39 ± 9.6 versus -43 ± 9.1, and -41 ± 10 mmHg, respectively. No difference (95% confidence interval) in the absolute change in SAP was observed between the groups (ANOVA, p = .29); medium versus low dose 3.7 (-2.0, 9.4) mmHg, and high versus medium dose -2.2 (-8.0; 3.5) mmHg. The relative changes from baseline to minimum SAP values were -30% versus -32% versus -32% (p = .52). The between-group differences in the AUC were not statistically significant. Relative changes in heart rate (-20% vs. -21% vs. -21%), stroke volume (-19% vs. -16% vs. -16%), cardiac output (-32% vs. -32% vs. -32%), systemic vascular resistance (-24% vs. -27% vs. -28%), and AUC were not statistically significant.

CONCLUSION

This trial demonstrated major haemodynamic changes during the induction of anaesthesia with remifentanil and propofol. However, we did not observe any statistically significant differences between low, medium or high doses of remifentanil when using continuous invasive high-accuracy beat-to-beat monitoring.

Anesthetic management in patients having catheter-based thrombectomy for acute pulmonary embolism: A narrative review

Pulmonary embolism is the third leading cause of cardiovascular death. Novel percutaneous catheter-based thrombectomy techniques are rapidly becoming popular in high-risk pulmonary embolism - especially in the presence of contraindications to thrombolysis. The interventional nature of these procedures and the risk of sudden cardiorespiratory compromise requires the presence of an anesthesiologist. Facilitating catheter-based thrombectomy can be challenging since qualifying patients are often critically ill. The purpose of this narrative review is to provide guidance to anesthesiologists for the assessment and management of patients having catheter-based thrombectomy for acute pulmonary embolism. First, available techniques for catheter-based thrombectomy are reviewed. Then, we discuss definitions and application of common risk stratification tools for pulmonary embolism, and how to assess patients prior to the procedure. An adjudication of risks and benefits of anesthetic strategies for catheter-based thrombectomy follows. Specifically, we give guidance and rationale for use monitored anesthesia care and general anesthesia for these procedures. For both, we review strategies for assessing and mitigating hemodynamic perturbations and right ventricular dysfunction, ranging from basic monitoring to advanced inodilator therapy. Finally, considerations for management of right ventricular failure with mechanical circulatory support are discussed.

Development of a three-dimensional computer model of the equine heart using a polyurethane casting technique and in vivo contrast-enhanced computed tomography

INTRODUCTION/OBJECTIVES

Insight into the three-dimensional (3D) anatomy of the equine heart is essential in veterinary education and to develop minimally invasive intracardiac procedures. The aim was to create a 3D computer model simulating the in vivo anatomy of the adult equine heart.

ANIMALS

Ten horses and five ponies.

MATERIALS AND METHODS

Ten horses, euthanized for non-cardiovascular reasons, were used for in situ cardiac casting with polyurethane foam and subsequent computed tomography (CT) of the excised heart. In five anaesthetized ponies, a contrast-enhanced electrocardiogram-gated CT protocol was optimized to image the entire heart. Dedicated image processing software was used to create 3D models of all CT scans derived from both methods. Resulting models were compared regarding relative proportions, detail and ease of segmentation.

RESULTS

The casting protocol produced high detail, but compliant structures such as the pulmonary trunk were disproportionally expanded by the foam. Optimization of the contrast-enhanced CT protocol, especially adding a delayed phase for visualization of the cardiac veins, resulted in sufficiently detailed CT images to create an anatomically correct 3D model of the pony heart. Rescaling was needed to obtain a horse-sized model.

CONCLUSIONS

Three-dimensional computer models based on contrast-enhanced CT images appeared superior to those based on casted hearts to represent the in vivo situation and are preferred to obtain an anatomically correct heart model useful for education, client communication and research purposes. Scaling was, however, necessary to obtain an approximation of an adult horse heart as cardiac CT imaging is restricted by thoracic size.

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.

Exploration of the Utility of Speckle-Tracking Echocardiography During Mechanical Ventilation and Mechanical Circulatory Support

This narrative review aims to discuss the potential applicability of speckle-tracking echocardiography (STE) in patients under mechanical ventilation (MV) and mechanical circulatory support (MCS). Both its benefits and limitations were considered through critical analyses of the current available evidence.

Comparison of effects of sevoflurane versus propofol on left ventricular longitudinal global and regional strain in patients undergoing on-pump coronary artery bypass grafting

Background:

Assessment of myocardial deformation by quantifying peak systolic longitudinal strain (PSLS) is a sensitive and robust index to detect subclinical myocardial dysfunction. We hypothesize that sevoflurane by virtue of anesthetic preconditioning preserves myocardial function better than propofol.

Aims:

The authors have assessed the effects of sevoflurane and propofol on global longitudinal strain (GLS) as a primary outcome in patients undergoing on-pump coronary artery bypass grafting. Our secondary aim was to assess the pattern of regional distribution of segmental PSLS between the groups.

Materials and Methods:

Fifty patients with normal left ventricular function undergoing coronary artery bypass grafting were analyzed in this prospective observational study. Consecutive patients received either propofol (P) or sevoflurane (S) anesthesia.

Measurements:

Trans-esophageal echocardiographic images (mid-esophageal four-chamber, two-chamber, and three-chamber (long-axis)) were recorded during the precardiopulmonary bypass (CPB) and post-CPB period. Strain analysis (GLS/segmental PSLS) was done offline by investigators blinded to the study. The inotropic score, duration of inotropic support, and mechanical ventilation required were recorded.

Results:

Following cardiopulmonary bypass and coronary revascularization, GLS reduced significantly in both the groups (P < 0.05). In the S-group, significant reduction in segmental strain was observed only in apical segments including apex, whereas in P-group significant reduction in segmental strain was seen in mid- and apical segments. The postoperative VIS, duration of inotropes/vasopressor required, and mechanical ventilation were similar in both the groups.

Conclusions:

There are no significant differences in global left ventricular function as assessed by GLS between patients anesthetized with sevoflurane or propofol. However, regional PSLS was better preserved in the S-group compared to P-group.

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.

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.