Perioperative Changes of Right Ventricular Function in Cardiac Surgical Patients Assessed by Myocardial Deformation Analysis and 3-Dimensional Echocardiography

Machine learning prediction of right ventricular volume and ejection fraction from two-dimensional echocardiography in patients with pulmonary regurgitation

Right ventricular (RV) end-diastolic volume (RVEDV) and ejection fraction (RVEF) by cardiac MRI (cMRI) guide management in chronic pulmonary regurgitation (PR). Two-dimensional echocardiography suboptimally correlate with RV volumes. This study tested whether combination of guideline-directed RV measures in a machine learning (ML) framework improves quantitative assessment of RVEDV and RVEF. RV measurements were obtained on subjects with > mild PR who had cMRI and echocardiogram within 90 days. A gradient-boosted trees algorithm predicted cMRI RV dilation (RVEDV > 160 ml/m2) and RV dysfunction (RVEF<47%), first with "guideline-only" measures, and then with "expanded-features" to include 44 total echocardiographic, clinical, and demographic variables. Model performance was compared to clinician visual assessment. Of 232 studies (56% tetralogy of Fallot, 20% pulmonary stenosis), the median age was 21.5 years, 21 (9%) had RV dilation, and 42 (18%) had RV dysfunction. For RV dilation prediction, the guideline-only model area under the receiver operating characteristic (AUROC)=0.68, and expanded-features model AUROC=0.85. At 90% sensitivity, the expanded-features model had 73% specificity, 25% positive predictive value (PPV), and 99% negative predictive value (NPV) This was similar to clinician performance (sensitivity 81%, specificity 81%, PPV 29%, NPV 98%). For prediction of RV dysfunction, the guideline-only AUROC= 0.71, additional features did not improve the model, and clinicians outperformed the model. In patients with PR, a ML model combining guidelines for RV assessment with demographic and additional echocardiographic parameters may effectively rule-out those with significant RV dilation at clinical thresholds for intervention, and performs similarly to expert clinicians.

Comparison of Manual and Mechanical Ventilation During Intensive Care Unit Transport Following Cardiac Surgery: Impact on Oxygenation, Ventilation, and Hemodynamic Stability

OBJECTIVES

Following cardiac surgery, patients often require ventilatory support during transport to the intensive care unit (ICU). Manual ventilation using a bag valve mask (BVM) is commonly employed; however, mechanical ventilation may sometimes be preferred due to concerns regarding oxygenation, ventilation, and hemodynamic stability. The decision between manual and mechanical ventilation is typically based on clinical experience and surgical factors, as there is no established consensus or robust clinical evidence to guide this choice. The aim of this study was to compare oxygenation, ventilation, and hemodynamic parameters between manual ventilation with a BVM and mechanical ventilation using a transport ventilator.

DESIGN

A prospective, single-blinded clinical trial.

SETTING

A single-center tertiary academic hospital.

PARTICIPANTS

A total of 48 patients who underwent cardiac surgery and were transported to the ICU between September 2023 and August 2024 were enrolled.

INTERVENTIONS

Patients meeting the inclusion criteria were randomly assigned to one of two groups: Patients in Arm 1received manual ventilation using a BVM during transport to the ICU; patients in Arm 2 received mechanical ventilation using a transport ventilator during transport to the ICU.

MEASUREMENTS AND MAIN RESULTS

Percentage changes in the PaO2/FiO2 ratio and PaCO2 pre- and post-transport were not significantly different between the two groups (p = 0.133 and 0.902, respectively). However, hypotension, defined as a >10% decrease in mean arterial pressure, was significantly more frequent in the BVM group than in the mechanical ventilation group (p = 0.00986).

CONCLUSIONS

In patients who have undergone cardiac surgery, hypotension occurred more frequently in the BVM group than in the mechanical ventilation group during transport to the ICU. However, oxygenation and ventilation parameters were comparable between the two groups.

Right Ventricular Diastolic Dysfunction Before Coronary Artery Bypass Grafting: Impact on 5-Year Follow-Up Outcomes

Background: The aim of this study was to assess the effect of right ventricular diastolic dysfunction on the results of 5-year follow-up of patients after coronary artery bypass grafting (CABG). Methods: Patients were enrolled in this prospective observational study examined before planned CABG from 2017 to 2018. In addition to the baseline preoperative indicators and perioperative data, the initial parameters of the left and right ventricle (RV) systolic and diastolic function were assessed. The long-term results after CABG were assessed after 5 years. The following endpoints were recorded in the remote period: coronary and non-coronary death, non-fatal myocardial infarction (MI), repeat myocardial revascularization. Results: The results of long-term follow-up were assessed in 148 patients, during which time MACE was registered in 43 patients (29.1%). In the group with MACE before CABG, a history of myocardial infarction (p = 0.008), functional class 3 NYHA of chronic heart failure (CHF) (p = 0.013), an increase in the left ventricle size, a decrease in the e'/a' ratio (p = 0.041), and the presence of the right ventricle diastolic dysfunction (p = 0.037) were more often detected. Kaplan-Meier analysis revealed a better long-term prognosis (MACE-free survival) in the group without RVDD compared to the group with RVDD (p = 0.026). Conclusions: In patients after coronary artery bypass grafting, the development of adverse events was associated with both clinical factors and the presence of right ventricular diastolic dysfunction. Survival analysis revealed a worse prognosis in patients with preoperative RVDD compared with patients without RVDD.

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.

Myocardial protection using single dose del Nido Cardioplegia with and without topical cooling

INTRODUCTION

Del Nido cardioplegia (DN) is gaining acceptance in adult cardiac surgery but there is paucity of experimental data regarding its efficacy. We set out to assess the safety and efficacy of single-dose DN with and without topical cooling (TC) versus multi-dose blood cardioplegia (BC).

METHODS

Thirty-two healthy adult sheep had pressure-volume (PV) catheters placed in the left (LV) and right (RV) ventricle. Animals were assigned to receive cold (4°C) antegrade solution for a 60-min arrest using: (1) multi-dose (every 20 min) BC with TC (n = 11), (2) single-dose DN with TC (DN-C, n = 10), or (3) single-dose DN without TC (DN-H, n = 11). LV and RV PV-derived indexes, epicardial echocardiographic strains, and blood samples were acquired before CPB and at 1, 2, and 3 h of reperfusion. Dobutamine bolus (2.5 μg) was given after 3 h to test for myocardial reserve.

RESULTS

Time to rhythm restoration was shortest (54 ± 29 s, 118 ± 167 s, and 172 ± 170 s for DN-H, DN-C, and BC, respectively; p = 0.024) and number of shocks lowest (1.7 ± 1.8, 3.6 ± 2.8, and 5.6 ± 4.6 for DN-H, DN-C, and BC, respectively; p = 0.020) in DN-H group. Hemodynamic, load-independent myocardial function, echocardiographic, and metabolic data revealed only slight differences between groups. Troponin I levels did not differ between groups. With dobutamine, preload-recruitable stroke work of both LV (136 ± 50%, 131 ± 31%, 142 ± 58% for BC, DN-C and DN-H, respectively; p = 0.993) and RV (161 ± 67%, 185 ± 45%, 166 ± 75% for BC, DN-C and DN-H respectively; p = 0.580) increased similarly.

CONCLUSIONS

Single-dose DN cardioplegia with or without topical cooling offered comparable biventricular myocardial protection to multi-dose BC for a 60-min arrest in sheep.

The Postoperative Paradoxical Septum (POPS): A Comprehensive Review on Physio-Pathological Mechanisms

The interventricular septum (IVS) is a core myocardial structure involved in biventricular coupling and performance. Physiologically, during systole, it moves symmetrically toward the center of the left ventricle (LV) and opposite during diastole. Several pathological conditions produce a reversal or paradoxical septal motion, such as after uncomplicated cardiac surgery (CS). The postoperative paradoxical septum (POPS) was observed in a high rate of cases, representing a unicum in the panorama of paradoxical septa as it does not induce significant ventricular morpho-functional alterations nor negative clinical impact. Although it was previously considered a postoperative event, evidence suggests that it might also appear during surgery and gradually resolve over time. The mechanism behind this phenomenon is still debated. In this article, we will provide a comprehensive review of the various theories generated over the past fifty years to explain its pathological basis. Finally, we will attempt to give a heuristic interpretation of the biventricular postoperative motion pattern based on the switch of the ventricular anchor points.

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.

Trileaflet Semilunar Valve Reconstruction: Acute Porcine in Vivo Evaluation

Objective: The surgical treatment of malformed semilunar valves in congenital heart defects is challenging in terms of providing both longevity and the potential to grow with the recipient. We investigated a new surgical technique "Trileaflet Semilunar Valve Reconstruction" in an acute porcine model, a technique with geometrical properties that could remain sufficient and allow for some growth with the child. Methods: An acute 60-kg porcine model was used. With echocardiography, baseline pulmonary valvular geometry and hemodynamics were investigated. On cardiopulmonary bypass, the pulmonary leaflets were explanted, and the Trileaflet Semilunar Valve Reconstruction was performed with customized homograft-treated pericardial neo-leaflets. Off bypass, hemodynamics was reassessed. Results: Twelve animals were investigated. The neo-valves were found sufficient in ten animals and with minimal regurgitation in two animals. The neo-valve had a peak gradient of 3 ± 2 mm Hg with a peak velocity of 0.8 ± 0.2 m/s. The coaptation in the neo-valve had a mean increase of 4 ± 3 mm, P < .001. The neo-valve had a windmill shape in the echocardiographic short-axis view, and the neo-leaflets billowed at the annular plane in the long-axis view. Conclusions: In this acute porcine model, the neo-valve had no clinically significant regurgitation or stenosis. The neo-valve had an increased coaptation, a windmill shape, and leaflets that billowed at the annular plane. These geometric findings may allow for sustained sufficiency as the annular and pulmonary artery dimension increase with the child's growth. Further long-term studies should be performed to evaluate the efficacy and the growth potential.

The Early Effects on Tricuspid Annulus and Right Chambers Dimensions in Successful Tricuspid Valve Bicuspidization

BACKGROUND

It is unclear to what degree of tricuspid annulus (TA) reduction is necessary to achieve good postoperative results in surgical bicuspidization. The study aimed to evaluate TA and right heart chamber's dimensions before and after heart surgery; and to compare TA parameters assessed by different modalities.

METHODS

Forty patients underwent mitral valve surgery with or without concomitant tricuspid valve (TV) bicuspidization. Preoperative and postoperative measurements of TA dimensions were performed prospectively using two-dimensional (2D) and three-dimensional (3D) transthoracic echocardiography (TTE). Additionally, preoperative transesophageal echocardiography (TOE) was performed in the operating room prior to surgery.

RESULTS

All patients had no or mild TR immediately after surgery. There was a significant reduction in 2D and 3D parameters of the TV and right chambers in the TV bicuspidization group. However, TV leaflets' tethering parameters did not change significantly. Preoperative 3D TTE measurements were smaller than those obtained through 3D TOE in the operation room, before surgery under general anesthesia. The 2D systolic apical 4Ch diameter and the parasternal short axis diameter mainly represent the 3D minor axis of the TA and are smaller than its 3D major axis.

CONCLUSIONS

Although bicuspidization results in a one-third reduction of the TV area, tethering of the TV leaflets remains unchanged. Moreover, 3D TOE parameters of the TV under general anesthesia are larger than preoperative 3D TTE measurements. Conventional 2D measurements are insufficient for evaluating the maximum diameter of the TA.

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.

Pulmonary Artery Banding for Dilated Cardiomyopathy in Children: Returning to the Bench from Bedside

Current treatment paradigms for end-stage dilated cardiomyopathy (DCM) in children include heart transplantation and mechanical support devices. However, waitlist mortality, shortage of smaller donors, time-limited durability of grafts, and thrombo-hemorrhagic events affect long-term outcomes. Moreover, both these options are noncurative and cannot preserve the native heart function. Pulmonary artery banding (PAB) has been reinvented as a possible “regenerative surgery” to retrain the decompensated left ventricle in children with DCM. The rationale is to promote positive ventricular–ventricular interactions that result in recovery of left ventricular function in one out of two children, allowing transplantation delisting. Although promising, global experience with this technique is still limited, and several surgical centers are reluctant to adopt PAB since its exact biological bases remain unknown. In the present review, we summarize the clinical, functional, and molecular known and supposed working mechanisms of PAB in children with DCM. From its proven efficacy in the clinical setting, we described the macroscopic geometrical and functional changes in biventricular performance promoted by PAB. We finally speculated on the possible underlying molecular pathways recruited by PAB. An evidence-based explanation of the working mechanisms of PAB is still awaited to support wider adoption of this surgical option for pediatric heart failure.

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.

Perioperative right ventricular function and dysfunction in adult cardiac surgery-focused review (part 1-anatomy, pathophysiology, and diagnosis)

Right ventricle (RV) dysfunction and failure are now increasingly recognized as an important cause of perioperative morbidity and mortality after cardiac surgery. Although RV dysfunction is common, RV failure is very rare (0.1%) after routine cardiac surgery. However, it occurs in 3% of patients after heart transplantation and in up to 30% of patients after left ventricular assist device implantation. Significant RV failure after cardiac surgery has high mortality. Knowledge of RV anatomy and physiology are important for understanding RV dysfunction and failure. Echocardiography and haemodynamic monitoring are the mainstays in the diagnosis of RV dysfunction and failure. While detailed echocardiography assessment of right heart function has been extensively studied and validated in the elective setting, gross estimation of RV chamber size, function, and some easily obtained quantitative parameters on transesophageal echocardiography are useful in the perioperative setting. However, detailed knowledge of echocardiography parameters is still useful in understanding the differences in contractile pattern, ventriculo-arterial coupling, and interventricular dependence that ensue after open cardiac surgery.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12055-021-01240-y.

Paradoxical Septal Motion after Uncomplicated Cardiac Surgery: A Consequence of Altered Regional Right Ventricular Contractile Patterns

Paroxysmal interventricular septal motion (PSM) is the movement of the septum toward the right ventricle (RV) during cardiac systole. It occurs frequently after uncomplicated cardiac surgery (CS), including coronary bypass (on-pump and off-pump), valve repair or replacement, and with all types of incisions (sternotomy or mini-thoracotomy). It sometimes resolves quickly but may persist for months or become permanent. Global RV systolic function, stroke volume and ejection fraction remain normal after uncomplicated CS, but regional contractile patterns are altered. There is a decrease in longitudinal shortening but an increase in transverse shortening in the endocardial and epicardial right ventricular muscle fibers, respectively. PSM is a secondary event as there is no loss of septal perfusion or thickening. The increased RV transverse shortening (free wall to septal fibers) may modify septal movement resulting in PSM that compensates for the reduced RV longitudinal shortening, thus preserving normal global right ventricular function.

Assessment of Myocardial Function During Blood Pressure Manipulations Using Feature Tracking Cardiovascular Magnetic Resonance

Background: Coronary autoregulation is a feedback system, which maintains near-constant myocardial blood flow over a range of mean arterial pressure (MAP). Yet in emergency or peri-operative situations, hypotensive or hypertensive episodes may quickly arise. It is not yet established how rapid blood pressure changes outside of the autoregulation zone (ARZ) impact left (LV) and right ventricular (RV) function. Using cardiovascular magnetic resonance (CMR) imaging, measurements of myocardial tissue oxygenation and ventricular systolic and diastolic function can comprehensively assess the heart throughout a range of changing blood pressures.

Design and methods: In 10 anesthetized swine, MAP was varied in steps of 10–15 mmHg from 29 to 196 mmHg using phenylephrine and urapidil inside a 3-Tesla MRI scanner. At each MAP level, oxygenation-sensitive (OS) cine images along with arterial and coronary sinus blood gas samples were obtained and blood flow was measured from a surgically implanted flow probe on the left anterior descending coronary artery. Using CMR feature tracking-software, LV and RV circumferential systolic and diastolic strain parameters were measured from the myocardial oxygenation cines.

Results: LV and RV peak strain are compromised both below the lower limit (LV: Δ1.2 ± 0.4%, RV: Δ4.4 ± 1.2%, p < 0.001) and above the upper limit (LV: Δ2.1 ± 0.4, RV: Δ5.4 ± 1.4, p < 0.001) of the ARZ in comparison to a baseline of 70 mmHg. LV strain demonstrates a non-linear relationship with invasive and non-invasive measures of oxygenation. Specifically for the LV at hypotensive levels below the ARZ, systolic dysfunction is related to myocardial deoxygenation (β = −0.216, p = 0.036) in OS-CMR and both systolic and diastolic dysfunction are linked to reduced coronary blood flow (peak strain: β = −0.028, p = 0.047, early diastolic strain rate: β = 0.026, p = 0.002). These relationships were not observed at hypertensive levels.

Conclusion: In an animal model, biventricular function is compromised outside the coronary autoregulatory zone. Dysfunction at pressures below the lower limit is likely caused by insufficient blood flow and tissue deoxygenation. Conversely, hypertension-induced systolic and diastolic dysfunction points to high afterload as a cause. These findings from an experimental model are translatable to the clinical peri-operative environment in which myocardial deformation may have the potential to guide blood pressure management, in particular at varying individual autoregulation thresholds.

Study design for a randomized crossover study investigating myocardial strain analysis in patients with coronary artery disease at hyperoxia and normoxemia prior to coronary artery bypass graft surgery (StrECHO-O2)

BACKGROUND

Supplemental oxygen (O₂) is used routinely during anesthesia. In the treatment of acute myocardial infarction, it has been established that hyperoxia is to be avoided, whereas information on benefit and risk of hyperoxia in patients with stable coronary artery disease (CAD) remain scarce, especially in the setting of general anesthesia. This study will compare the immediate effects of normoxemia and hyperoxia on cardiac function, with a primary focus on changes in peak longitudinal left-ventricular strain, in anesthetized stable chronic CAD patients using peri-operative transesophageal echocardiography (TEE).

METHODS

A single-center randomized cross-over clinical trial will be conducted, enrolling 106 patients undergoing elective coronary artery bypass graft surgery. After the induction of anesthesia and prior to the start of surgery, cardiac function will be assessed by 2D and 3D TEE. Images will be acquired at two different oxygen states for each patient in randomized order. The fraction of inspired oxygen (F_IO₂) will be titrated to a normoxemic state (oxygen saturation of 95-98%) and adjusted to a hyperoxic state (F_IO₂ = 0.8). TEE images will be analyzed in a blinded manner for standard cardiac function and strain parameters.

CONCLUSION

By using myocardial strain assessed by TEE, early and subtle signs of biventricular systolic and diastolic dysfunction can be promptly measured intraoperatively prior to the onset of severe signs of ischemia. The results may help anesthesiologists to better understand the effects of F_IO₂ on cardiac function and potentially tailor oxygen therapy to patients with CAD undergoing general anesthesia.

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.

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.

Acute changes of global and longitudinal right ventricular function: an exploratory analysis in patients undergoing open-chest mitral valve surgery, percutaneous mitral valve repair and off-pump coronary artery bypass grafting

Background

Right ventricular (RV) function is an important prognostic indicator. The acute effects of cardiac interventions or cardiac surgery on global and longitudinal RV function are not entirely understood. In this study, acute changes of RV function during mitral valve surgery (MVS), percutaneous mitral valve repair (PMVR) and off-pump coronary artery bypass surgery (OPCAB) were investigated employing 3D echocardiography.

Methods

Twenty patients scheduled for MVS, 23 patients scheduled for PMVR and 25 patients scheduled for OPCAB were included retrospectively if patients had received 3D transesophageal echocardiography before and immediately after MVS, PMVR or OPCAB, respectively. RV global and longitudinal function was assessed using a 3D multiparameter set consisting of global right ventricular ejection fraction (RVEF), tricuspid annular plane systolic excursion (TAPSE), longitudinal contribution to RVEF (RVEF_long) and free wall longitudinal strain (FWLS).

Results

Longitudinal RV function was significantly depressed immediately after MVS, as reflected by all parameters (RVEF_long: 20 ± 5% vs. 13 ± 6%, p <  0.001, TAPSE: 13.1 ± 5.1 mm vs. 11.0 ± 3.5 mm, p = 0.04 and FWLS: −20.1 ± 7.1% vs. -15.4 ± 5.1%, p <  0.001, respectively). The global RVEF was slightly impaired, but the difference did not reach significance (37 ± 13% vs. 32 ± 9%, p = 0.15). In the PMVR group, both global and longitudinal RV function parameters were unaltered, whereas the OPCAB group showed a slight reduction of RVEF_long only (18 ± 7% vs. 14 ± 5%, p <  0.01). RVEF_long yielded moderate case-to-case but good overall reproducibility.

Conclusions

TAPSE, FWLS and RVEF_long reflect the depression of longitudinal compared to global RV function initially after MVS. PMVR alone had no impact, while OPCAB had a slight impact on longitudinal RV function. The prognostic implications of these phenomena remain unclear and require further investigation.

Changes in Right Ventricular Function After Off-Pump Coronary Artery Bypass Grafting

OBJECTIVE

Right ventricular (RV) dysfunction is associated with poor outcomes after cardiac surgery. The aim of this study was to assess RV systolic and diastolic function in the perioperative period after off-pump coronary artery bypass grafting (OPCAB).

DESIGN

Prospective observational study.

SETTINGS

Tertiary care hospital.

PARTICIPANTS

Thirty adult patients undergoing OPCAB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Transthoracic echocardiography was performed twice: first preoperatively and second postoperatively, when patients were moved to wards. The following five parameters of RV systolic function were used: tricuspid annular plane systolic excursion (TAPSE), systolic tissue Doppler imaging of lateral tricuspid annulus (S'), fractional area change (FAC), RV myocardial performance index (RIMP), and isovolumic acceleration (IVA). Grading of RV diastolic function (RVDD) was done as per guidelines. Paired t test was used for comparing means and χ² test was used for categorical and ordinal data. The parameters of RV longitudinal function (TAPSE and S') reduced significantly (preoperative 21.93 ± 2.80 mm and 13.24 ± 2.24 cm/s to postoperative 11.67 ± 1.91 mm and 10.31 ± 1.56 cm/s, respectively, p < 0.001), whereas parameters of RV global function (FAC, RIMP, and IVA) remained preserved (preoperative 46.75 ± 6.80%, 0.34 ± 0.06, and 4.66 ± 0.87 m/s² to postoperative 46.21 ± 6.44%, 0.36 ± 0.06, and 4.37 ± 0.83 m/s²; p values of 0.76, 0.13, and 0.11, respectively). The median grade of RVDD worsened from normal in the preoperative period to pseudo-normal in the postoperative period (p < 0.001). The changes in both RV systolic and diastolic function were similar in patients with normal and reduced left ventricular systolic function.

CONCLUSIONS

RV function can be assessed in perioperative settings with two-dimensional and tissue Doppler imaging. For systolic function assessment, exclusive measurement of longitudinal parameters might be inadequate; use of complementary global parameters like FAC, RIMP, and IVA is essential to complete the RV assessment after OPCAB. RVDD worsened significantly after OPCABG.