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

Evaluation of Intraoperative Right Ventricular Myocardial Work Indices in Left Ventricular Assist Device Implantation: A Case Report

Right ventricular myocardial work is an echocardiographic technique yielding significant insights into cardiac mechanics, energetics, and efficiency. Combining right ventricular myocardial strain with loading conditions correlates with invasively measured myocardial work and myocardial oxygen consumption. This method has not yet been described intraoperatively by transesophageal echocardiography. We describe this technique during a left ventricular assist device implantation. This case demonstrates that right ventricular myocardial work indices can be monitored intraoperatively and might assist decisions during left ventricular assist device implantation.

Echocardiographic Characteristics of Left and Right Ventricular Longitudinal Function in Patients With a History of Cardiac Surgery

Previous studies have indicated a reduction in right ventricular (RV) longitudinal motion after cardiac surgery. However, the long-term effect of cardiac surgery on longitudinal motion and the involvement of left ventricular (LV) motion remains unclear. Therefore, this study aimed to comprehensively investigate the longitudinal function of the right ventricle and left ventricle in patients who underwent cardiac surgery. The study included patients who underwent comprehensive transthoracic echocardiography with 3-dimensional RV data sets. By propensity score matching of the clinical and echocardiographic variables, including LV and RV ejection fraction, the echocardiographic parameters were compared between patients with and without a history of cardiac surgery (the surgery and nonsurgery groups, respectively). In this study, the surgery group had significantly lower LV global longitudinal strain values than the nonsurgery group, despite having similar LV ejection fraction. The tricuspid annular plane systolic excursion (TAPSE), tricuspid annular velocity, and RV free wall longitudinal strain were also significantly smaller in the surgery group, whereas the RV ejection fraction was comparable between the 2 groups. In addition, a subgroup analysis based on the time from previous surgery to transthoracic echocardiography (≤1 and >1 year) revealed that TAPSE was reduced in both postoperative phases. In conclusion, LV and RV longitudinal parameters were reduced after cardiac surgery, despite preserved LV and RV global functions. Moreover, TAPSE was reduced even after a long time after cardiac surgery. These findings emphasize the need for careful interpretation of biventricular longitudinal motion in patients with a history of cardiac surgery.

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.

Impact of sternotomy and pericardiotomy on cardiopulmonary haemodynamics in a large animal model

NEW FINDINGS

What is the central question of this study? Invasive cardiovascular instrumentation can occur through closed- or open-chest approaches. To what extent will sternotomy and pericardiotomy affect cardiopulmonary variables? What is the main finding and its importance? Opening of the thorax decreased mean systemic and pulmonary pressures. Left ventricular function improved, but no changes were observed in right ventricular systolic measures. No consensus or recommendation exists regarding instrumentation. Methodological differences risk compromising rigour and reproducibility in preclinical research.

ABSTRACT

Animal models of cardiovascular disease are often evaluated by invasive instrumentation for phenotyping. As no consensus exists, both open- and closed-chest approaches are used, which might compromise rigour and reproducibility in preclinical research. We aimed to quantify the cardiopulmonary changes induced by sternotomy and pericardiotomy in a large animal model. Seven pigs were anaesthetized, mechanically ventilated and evaluated by right heart catheterization and bi-ventricular pressure-volume loop recordings at baseline and after sternotomy and pericardiotomy. Data were compared by ANOVA or the Friedmann test where appropriate, with post-hoc analyses to control for multiple comparisons. Sternotomy and pericardiotomy caused reductions in mean systemic (-12 ± 11 mmHg, P = 0.027) and pulmonary pressures (-4 ± 3 mmHg, P = 0.006) and airway pressures. Cardiac output decreased non-significantly (-1329 ± 1762 ml/min, P = 0.052). Left ventricular afterload decreased, with an increase in ejection fraction (+9 ± 7%, P = 0.027) and coupling. No changes were observed in right ventricular systolic function or arterial blood gases. In conclusion, open- versus closed-chest approaches to invasive cardiovascular phenotyping cause a systematic difference in key haemodynamic variables. Researchers should adopt the most appropriate approach to ensure rigour and reproducibility in preclinical cardiovascular research.

Indicators of the Right Ventricle Systolic and Diastolic Function 18 Months after Coronary Bypass Surgery

Objective. Right ventricular (RV) dysfunction after coronary artery bypass grafting (CABG) is associated with increased mortality and morbidity. In previous studies, the parameters of RV systolic function were mainly assessed, while the dynamics of RV diastolic function after surgery was practically not studied. The aim of this study was to study the dynamics of indicators of systolic and diastolic RV function after CABG as well as to identify factors associated with their presence. Methods. The study included 160 patients who underwent CABG and 36 volunteers with no history of coronary artery disease (CAD) as a control group. Echocardiographic examination of patients was performed to assess systolic and diastolic RV dysfunction before surgery and 18 months after CABG. A level of s’t < 10 cm/sec or TAPSE < 16 mm was considered as a sign of existing RV systolic dysfunction. RV diastolic dysfunction was defined as an Et/At ratio < 0.8 or >2.1 and/or an Et/et’ ratio > 6. Results. In CAD patients 18 months after CABG, there was an increase in the frequency of the right ventricular systolic (from 7.5% to 30%, p < 0.001) and diastolic (from 41.8% to 57.5%, p < 0.001) dysfunction. An increase in TAPSE (p = 0.007), a decrease in e’t (p = 0.005), and the presence of RV systolic dysfunction before surgery (p = 0.023) was associated with a significant increase in the likelihood of detecting RV systolic dysfunction 18 months after CABG (χ2(3) = 17.4, p = 0.001). High values of At before surgery (p = 0.021) and old myocardial infarction (p = 0.023) were significantly associated with an increased likelihood of detection of RV diastolic dysfunction 18 months after CABG (χ2(2) = 10.78, p = 0.005). Conclusions. This study demonstrated that in CAD patients 18 months after CABG, there was an increase in the frequency of right ventricular systolic and diastolic dysfunction. We also established the initial clinical, echocardiographic parameters, and perioperative complications associated with the presence of these changes in the postoperative period. The clinical and prognostic significance of the presence of systolic and/or diastolic RV dysfunction in patients 18 months after CABG remains to be explored.

Right ventricular volume-strain loops using 3D echocardiography-derived mesh models: proof-of-concept application on patients undergoing different types of open-heart surgery

BACKGROUND

Right ventricular (RV) function can be quantified by right heart catheterization-derived pressure-volume loops. While this technique is invasive, echocardiography-based volume-strain loops (VSLs) potentially reflect a non-invasive alternative. In this study, an approach to generate VSLs from volume and multidimensional strain data of 3D echocardiography-derived RV mesh models is evaluated with regard to feasibility and reproducibility.

METHODS

In a retrospective cohort study design, 3D intraoperative transesophageal echocardiograms of twenty-three patients undergoing aortic valve surgery (AVS) and eighteen patients undergoing off-pump coronary artery bypass (OPCAB) grafting were available prior to sternotomy and after sternal closure. RV meshes were generated using 3D speckle-tracking. Custom-made software quantified the meshes' volumes, global longitudinal (RV-GLS) and global circumferential strain (RV-GCS) for VSL generation. Linear regression of systolic VSLs yielded slopes, intercepts and systolic areas. Polynomial regression of two orders was used to analyze systolic-diastolic coupling at 10% increments of the RV end-diastolic volume (RVEDV). Reproducibility was analyzed by fourfold double-measurements of four datasets.

RESULTS

VSL calculation was feasible from all included 3D datasets. RV-GLS remained unaltered, but RV-GCS worsened in AVS [abs. diff. (∆) 3.9%, P<0.01] and OPCAB patients (∆4.5%, P<0.001). While RV-GCS systolic areas were markedly reduced at the end of AVS (∆268mL%, P<0.01) and OPCAB (∆185mL%, P<0.001), RV-GCS slopes did not change. Systolic-diastolic uncoupling was not observed, but in trend, decreased diastolic RV-GCS after AVS (P=0.06) and increased diastolic RV-GCS after OPCAB (P=0.06) were observed. Intraclass correlation coefficients (0.84-0.98) and coefficients of variation (6.4-11.8%) indicated good reproducibility.

CONCLUSIONS

RV VSL generation using 3D echocardiography-derived mesh models is feasible. Longitudinal and circumferential strain vectors yield intrinsically different VSL indices. In future investigations, VSLs of multidimensional strains could provide further insight into periprocedural changes of RV mechanics.

New developments in the understanding of right ventricular function in acute care

PURPOSE OF REVIEW

Right ventricular dysfunction has an important impact on the perioperative course of cardiac surgery patients. Recent advances in the detection and monitoring of perioperative right ventricular dysfunction will be reviewed here.

RECENT FINDINGS

The incidence of right ventricular dysfunction in cardiac surgery has been associated with unfavorable outcomes. New evidence supports the use of a pulmonary artery catheter in cardiogenic shock. The possibility to directly measure right ventricular pressure by transducing the pacing port has expanded its use to track changes in right ventricular function and to detect right ventricular outflow tract obstruction. The potential role of myocardial deformation imaging has been raised to detect patients at risk of postoperative complications.

SUMMARY

Perioperative right ventricular function monitoring is based on echocardiographic and extra-cardiac flow evaluation. In addition to imaging modalities, hemodynamic evaluation using various types of pulmonary artery catheters can be achieved to track changes rapidly and quantitatively in right ventricular function perioperatively. These monitoring techniques can be applied during and after surgery to increase the detection rate of right ventricular dysfunction. All this to improve the treatment of patients presenting early signs of right ventricular dysfunction before systemic organ dysfunction ensue.

[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.

Association of Three-Dimensional Mesh-Derived Right Ventricular Strain with Short-Term Outcomes in Patients Undergoing Cardiac Surgery

BACKGROUND

Three-dimensional (3D) right ventricular (RV) strain analysis is not routinely performed perioperatively. Although 3D RV strain adds incrementally to outcome prediction in various cardiac diseases, its role in the perioperative setting is not sufficiently understood. The aim of this study was to investigate the association between 3D RV strain measured on RV meshes created from 3D transesophageal echocardiographic data and short-term outcomes among patients undergoing cardiac surgery.

METHODS

A total of 496 patients undergoing cardiac surgery who underwent intraoperative 3D transesophageal echocardiography (under general anesthesia, before sternotomy) were retrospectively selected, and RV meshes were generated using commercially available speckle-tracking software. Custom-made software automatically quantified longitudinal and circumferential RV strains on the mesh surfaces. Echocardiographic and clinical parameters were entered into logistic regression models to determine their associations with the primary (in-hospital death or need for extracorporeal life support) and secondary (postoperative ventilation > 48 hours) end points.

RESULTS

Mesh-derived RV strain analysis was feasible in 94% of patients and revealed distinct regional patterns with basal-apical gradients for both longitudinal and circumferential strain. Thirty-seven patients (7.6%) reached the primary end point, and 118 patients (23.8%) reached the secondary end point. In a multivariable logistic regression model, serum lactate (P < .01), an emergency indication for surgery (P < .01), tricuspid regurgitation (P < .001), and mesh-derived RV global longitudinal strain (RV-GLS; P < .01) were independently associated with the primary end point, while established measures of RV function (3D RV ejection fraction, fractional area change, tricuspid annular plane systolic excursion) and left ventricular (LV) function (3D-derived LV ejection fraction and LV-GLS) were not independently associated. Hematocrit (P < .01), serum lactate (P < .001), pulmonary hypertension (P = .04), tricuspid regurgitation (P < .01), emergency procedures (P = .02), LV-GLS (P = .02), and RV-GLS (P < .001) were associated with the secondary end point.

CONCLUSIONS

RV-GLS measured on RV meshes derived from 3D transesophageal echocardiography was independently associated with short-term outcomes in patients undergoing cardiac surgery and might be helpful for identifying patients at risk for adverse postoperative events.

Role of Echocardiography for the Perioperative Assessment of the Right Ventricle

Purpose of Review

This review aims to highlight the perioperative echocardiographic evaluation of right ventricular (RV) function with strengths and limitations of commonly used and evolving techniques. It explains the value of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) and describes the perioperative changes of RV function echocardiographers should be aware of.

Recent Findings

RV dysfunction is an entity with strong influence on outcome. However, its definition and assessment in the perioperative interval are not well-defined. Moreover, values assessed by TTE and TEE are not interchangeable; while some parameters seem to correlate well, others do not. Myocardial strain analysis and three-dimensional echocardiography may overcome the limitations of conventional echocardiographic measures and provide further insight into perioperative cardiac mechanics.

Summary

Echocardiography has become an essential part of modern anesthesiology in patients with RV dysfunction. It offers the opportunity to evaluate not only global but also regional RV function and distinguish alterations of RV contraction.