Improving risk assessment for post-surgical low cardiac output syndrome in patients without severely reduced ejection fraction undergoing open aortic valve replacement. The role of global longitudinal strain and right ventricular free wall strain

Prognostic value of right ventricular free-wall longitudinal strain in aortic stenosis: A systematic review and meta-analysis

BACKGROUND

Assessment of right ventricular (RV) function in aortic stenosis (AS) may improve risk stratification. However, whether the prognostic value of RV free-wall longitudinal strain (RVfwLS) is better than that of other right heart or pulmonary circulation parameters remains uncertain. This study assessed and compared the prognostic value of RVfwLS with traditional parameters in the AS population using a systematic review and meta-analysis.

METHODS

We selected studies reporting the hazard ratio (HR) of RVfwLS in patients with AS. We also collected data regarding the HR of systolic pulmonary arterial pressure (SPAP), fractional area change (FAC), and tricuspid annulus plane systolic excursion (TAPSE). To ensure comparability, we standardized the HR using within-study standard deviations. The comparison between the prognostic value of RVfwLS and other parameters was conducted as a ratio of HR.

RESULTS

This meta-analysis included 9 studies comprising a total of 2547 patients, with 679 events. The pooled HR of RVfwLS was 1.56 (95 % CI: 1.39-1.75, p < 0.001). When examining the ratio of HR between RVfwLS and conventional parameters, all comparisons were statistically non-significant [RVfwLS/SPAP: 1.28 (95 % CI: 0.99-1.65, p = 0.06); RVfwLS/FAC: 1.24 (95 % CI: 0.90-1.72, p = 0.14); and RVfwLS/TAPSE:1.07 (95 % CI: 0.75-1.52, p = 0.60)].

CONCLUSIONS

This meta-analysis establishes a substantial association between RVfwLS and adverse outcomes in the AS population. However, comparative analysis between RVfwLS and SPAP, FAC, or TAPSE did not support the prognostic superiority of RVfwLS.

Right ventricular function in severe aortic stenosis assessed by echocardiography and MRI

BACKGROUND

The prevalence of aortic valve stenosis (AS) is increasing due to an ageing population. Despite that right ventricular function has prognostic value for postoperative outcome, the right ventricle (RV) is not extensively studied and often not routinely assessed in AS. Our aim was to explore the relation between severe AS and RV function in a surgical aortic valve replacement (SAVR) cohort, comparing two imaging modalities for RV evaluation.

METHODS

Patients with severe AS, underwent cardiovascular magnetic resonance imaging (CMR) and transthoracic echocardiography (TTE) before SAVR. RV dysfunction was defined as one or more of the following: tricuspid annular plane systolic excursion (TAPSE) < 17 mm, RV free wall strain (RVFWS) > -20% by TTE and RV ejection fraction (RVEF) <50% by CMR.

RESULTS

Sixteen (33%) patients were found to have RV dysfunction. Patients with RV dysfunction showed significantly lower indexed aortic valve area, left ventricular (LV) ejection fraction as well as RV and LV stroke volumes compared to patients with maintained RV function. All patients with reduced RVEF also had changes in TAPSE or RVFWS and a larger number of patients had a reduced longitudinal RV function despite a normal RVEF.

CONCLUSION

In a SAVR cohort one-third of the patients had RV dysfunction, defined by RVEF, TAPSE or RVFW strain. Echocardiography detected subtle changes in RV function before RVEF was reduced. It is likely that the more pronounced the AS, the more frequent the occurrence of RV dysfunction.

Right ventricular free wall and four-chamber longitudinal strain in relation to incident heart failure in the general population

AIMS

Right ventricular free wall (RVFWLS) and four-chamber longitudinal strain (RV4CLS) are associated with adverse events in various patient populations including patients with heart failure (HF). We sought to investigate the prognostic value of RVFWLS and RV4CLS for the development of incident HF in participants from the general population.

METHODS AND RESULTS

Participants from the 5th Copenhagen City Heart Study (2011-2015) without known chronic ischaemic heart disease or HF at baseline were included. RVFWLS and RV4CLS were obtained using two-dimensional speckle-tracking echocardiography from the right ventricular (RV)-focused apical four-chamber view. The primary endpoint was incident HF. Among 2740 participants (mean age 54 ± 17 years, 42% male), 43 (1.6%) developed HF during a median follow-up of 5.5 years (IQR 4.5-6.3). Both RVFWLS and RV4CLS were associated with an increased risk of incident HF during follow-up independent of age, sex, hypertension, diabetes, body mass index and tricuspid annular plane systolic excursion (TAPSE), (HR 1.06, 95%CI 1.00-1.11, P = 0.034, per 1% absolute decrease and HR 1.14, 95%CI 1.05-1.23, P = 0.001, per 1% absolute decrease, respectively). Left ventricular ejection fraction (LVEF) modified the association between RV4CLS and incident HF (P for interaction = 0.016) such that RV4CLS was only of prognostic importance among those with LVEF < 55% (HR 1.21, 95%CI 1.11-1.33, P < 0.001 vs. HR 0.94, 95%CI 0.80-1.10, P = 0.43 in patients with LVEF ≥ 55%).

CONCLUSION

In participants from the general population, both RVFWLS and RV4CLS were associated with a greater risk of incident HF independent of important baseline characteristics and TAPSE, and LVEF modified the relationship between RV4CLS and incident HF.

A novel interpretative tool for early prediction of low cardiac output syndrome after valve surgery: online machine learning models

OBJECTIVE

Low cardiac output syndrome (LCOS) is a severe complication after valve surgery, with no uniform standard for early identification. We developed interpretative machine learning (ML) models for predicting LCOS risk preoperatively and 0.5 h postoperatively for intervention in advance.

METHODS

A total of 2218 patients undergoing valve surgery from June 2019 to Dec 2021 were finally enrolled to construct preoperative and postoperative models. Logistic regression, support vector machine (SVM), random forest classifier, extreme gradient boosting, and deep neural network were executed for model construction, and the performance of models was evaluated by area under the curve (AUC) of the receiver operating characteristic and calibration curves. Our models were interpreted through SHapley Additive exPlanations, and presented as an online tool to improve clinical operability.

RESULTS

The SVM algorithm was chosen for modeling due to better AUC and calibration capability. The AUCs of the preoperative and postoperative models were 0.786 (95% CI 0.729-0.843) and 0.863 (95% CI 0.824-0.902), and the Brier scores were 0.123 and 0.107. Our models have higher timeliness and interpretability, and wider coverage than the vasoactive-inotropic score, and the AUC of the postoperative model was significantly higher. Our preoperative and postoperative models are available online at http://njfh-yxb.com.cn:2022/lcos.

CONCLUSIONS

The first interpretable ML tool with two prediction periods for online early prediction of LCOS risk after valve surgery was successfully built in this study, in which the SVM model has the best performance, reserving enough time for early precise intervention in critical care.

Early-Stage Vasoactive-Inotropic Score and Left Ventricular Ejection Fraction Following Cardiac Surgery: A Comparison of Two Non-invasive Heart Function Monitoring Technologies in the Prognosis of Infants

Objectives: This study aimed to compare the efficiencies of the vasoactive-inotropic score (VIS) and left ventricular ejection fraction (LVEF) in predicting the condition and prognosis of children with congenital heart disease (CHD). Methods: We retrospectively reviewed the medical charts of 104 infants aged < 1 year who underwent cardiac surgery with cardiopulmonary bypass. The maximum and mean postoperative VIS in the first and second 24 hours [VIS (24MAX), VIS (24MEA), VIS (48MAX), and VIS (48MEA)] were recorded. Similarly, LVEF within 24 hours following surgery was monitored. Receiver operator curve (ROC), regression analysis, chi-square test, and t-test were used to analyze both heart function monitoring technologies Results: Receiver operating characteristic analysis revealed that VIS was strongly associated with adverse events and death [area under ROC (AUROC) > 0.90, P = 0.00], with the two most representative scores being VIS (24MEA) and VIS (48MAX), with cut-off points of 19.42 (sensitivity = 100%; specificity = 93.90%) and 22 (sensitivity = 100%; specificity = 93.90%), respectively for death, and 18.02 (sensitivity = 91.70%; specificity = 89.10%) and 17.75 (sensitivity = 91.70%; specificity = 90.20%), respectively for adverse events. Infants with higher VIS had significantly higher mortality, higher incidence of clinical adverse events, higher lactic acid value, and longer mechanical ventilation and ICU stay (P < 0.05). However, LVEF within 24 hours following surgery was not associated with death (AUROC = 0.65, P = 0.33) or adverse events (AUROC = 0.53, P = 0.81). Moreover, there was no significant change in the length of ICU stay, duration of mechanical ventilation, and lactate value (P > 0.05). Conclusions: Vasoactive-inotropic score at an early stage following surgery was significantly associated with the condition and prognosis of infants with congenital heart disease; however, the predictive value of LVEF within 24 hours following surgery was lower.

The Predictive Value of Right Ventricular Longitudinal Strain in Pulmonary Hypertension, Heart Failure, and Valvular Diseases

Right ventricular (RV) systolic function has an important role in the prediction of adverse outcomes, including mortality, in a wide range of cardiovascular (CV) conditions. Because of complex RV geometry and load dependency of the RV functional parameters, conventional echocardiographic parameters such as RV fractional area change (FAC) and tricuspid annular plane systolic excursion (TAPSE), have limited prognostic power in a large number of patients. RV longitudinal strain overcame the majority of these limitations, as it is angle-independent, less load-dependent, highly reproducible, and measure regional myocardial deformation. It has a high predictive value in patients with pulmonary hypertension, heart failure, congenital heart disease, ischemic heart disease, pulmonary embolism, cardiomyopathies, and valvular disease. It enables detection of subclinical RV damage even when conventional parameters of RV systolic function are in the normal range. Even though cardiac magnetic resonance-derived RV longitudinal strain showed excellent predictive value, echocardiography-derived RV strain remains the method of choice for evaluation of RV mechanics primarily due to high availability. Despite a constantly growing body of evidence that support RV longitudinal strain evaluation in the majority of CV patients, its assessment has not become the part of the routine echocardiographic examination in the majority of echocardiographic laboratories. The aim of this clinical review was to summarize the current data about the predictive value of RV longitudinal strain in patients with pulmonary hypertension, heart failure and valvular heart diseases.

Analysis of risk factors of low cardiac output syndrome after congenital heart disease operation: what can we do

Background

It’s necessary to analyze the related risk factors and complications of low cardiac output syndrome (LCOS) after operation in children with congenital heart disease (CHD), to elucidate the management strategy of LCOS.

Methods

CHD children admitted to the department of cardiology in our hospital from January 15, 2019 to October 31, 2020 were included. The personal and clinical data of CHD children with LCOS and without LCOS were collected and compared. Logistic regression analyses were conducted to identify the risk factors of postoperative LCOS. Besides, the complication and mortality of LCOS and no LCOS patients were compared.

Results

A total of 283 CHD patients were included, the incidence of postoperative LCOS in CHD patients was 12.37%. There were significant differences in the age, preoperative oxygen saturation, two-way ventricular shunt, duration of CPB and postoperative residual shunt between two groups (all p < 0.05). Logistic regression analyses indicated that age ≤ 4y(OR2.426, 95%CI1.044 ~ 4.149), preoperative oxygen saturation ≤ 93%(OR2.175, 95%CI1.182 ~ 5.033), two-way ventricular shunt (OR3.994, 95%CI1.247 ~ 6.797), duration of CPB ≥ 60 min(OR2.172, 95%CI1.002 ~ 4.309), postoperative residual shunt (OR1.487, 95%CI1.093 ~ 2.383) were the independent risk factors of LCOS in patients with CHD (all p < 0.05). There were significant differences in the acute liver injury, acute kidney injury, pulmonary infection, tracheotomy, duration of mechanical ventilation, length of ICU stay and mortality (all p < 0.05), no significant difference in the 24 h drainage was found(p = 0.095).

Conclusion

LCOS after CHD is common, more attentions should be paid to those patients with age ≤ 4y, preoperative oxygen saturation ≤ 93%, two-way ventricular shunt, duration of CPB ≥ 60 min, postoperative residual shunt to improve the prognosis of CHD patients.

Right Ventricular Longitudinal Strain Predicts Low-Cardiac- Output Syndrome After Surgical Aortic Valve Replacement in Patients With Preserved and Mid-range Ejection Fraction

OBJECTIVES

The aim of this study was to analyze whether right ventricular free wall longitudinal strain (RVFWSL) could be a predictor of low-cardiac-output syndrome (LCOS) after surgical aortic valve replacement (SAVR) in patients with left ventricular ejection fraction ≥40%.

DESIGN

Prospective, observational study.

SETTING

The study was conducted at a third level university hospital.

PARTICIPANTS

The study comprised 75 patients with severe aortic stenosis and LVEF ≥40% who underwent SAVR. The primary outcome was the occurrence of LCOS, and secondary outcomes were in-hospital mortality, hospital stay, or vasoplegic syndrome.

INTERVENTIONS

Patients were divided into two groups (LCOS and no LCOS), and RVFWSL was analyzed to determine whether it is a predictor for LCOS. In addition, a receiver operating characteristic curve also was constructed, and the best cutoff value to predict LCOS was found. Furthermore, the reproducibility of RVFWSL measurements was evaluated.

MEASUREMENT AND MAIN RESULTS

The incidence of LCOS was 20% in the present study's cohort. After multivariate analysis, cross-clamp time (odds ratio 1.06, 95% confidence interval 1.02-1.11; p = 0.002) and RVFWSL (odds ratio 1.41, 95% confidence interval 1.07-1.87; p = 0.015) were the only predictors of LCOS. However, RVFWSL did not show association with secondary outcomes (p > 0.05 for all). The area under the curve of RVFWSL to predict LCOS was 0.75, and the best cutoff value was -17.3%, with a sensitivity of 86.7% and specificity of 61.7%.

CONCLUSIONS

RVFWSL seems to be a predictor of LCOS in patients with severe aortic stenosis and LVEF ≥40% undergoing SAVR. RVFWSL less than -17.3% may identify patients at increased risk for LCOS.

Left ventricular global longitudinal strain and cardiac surgical outcomes

Global longitudinal strain (GLS) has emerged as a valuable diagnostic and prognostic tool for evaluating left ventricular (LV) function. GLS has been shown to be a more sensitive marker of LV dysfunction than LV ejection fraction alone and have prognostic impact in non-surgical cardiac populations. GLS, is validated, reproducible, and easily obtained from 2-dimensional speckle-tracking echocardiography. While there is strong evidence for using GLS in clinical decision-making in non-surgical populations, there is less summarized evidence on using GLS in the cardiac surgical population. This review combines the evidence on the implications of using baseline transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) GLS in cardiac surgical populations including ischemic and structural heart disease to determine surgical outcomes. We found that results seem promising on the prognostic utility of LV strain in cardiac surgical populations. However due to the variability of study populations and outcomes, and modalities (TTE versus TEE), further research on normal versus abnormal values for different surgical populations, as well potential treatment options that may modify and potentially decrease surgical risk for those with abnormal GLS are needed.

Risk factors for low cardiac output syndrome in children with congenital heart disease undergoing cardiac surgery: a retrospective cohort study

Background

Low cardiac output syndrome (LCOS) is an important complication of cardiac surgery. It is associated with increased morbidity and mortality. The incidence of LCOS after surgery is high in patients with congenital heart disease (CHD). Therefore, determining the risk factors of LCOS has clinical significance for the management of CHD. This study aimed to analyze the risk factors of LCOS.

Methods

We conducted a retrospective analysis of children with CHD who underwent cardiac surgery at Shanghai Children’s Medical Center between January 1, 2014, and December 31, 2017. Demographic characteristics and baseline data were extracted from the health data resource center of the hospital, which integrates clinical routine data including medical records, diagnoses, orders, surgeries, laboratory tests, imaging, nursing, and other subsystems. Logistic regressions were performed to analyze the risk factors of LCOS.

Results

Overall, 8660 infants with CHD were included, and 864 (9.98%) had LCOS after surgery. The multivariate regression analysis identified that age (OR 0.992, 95% CI: 0.988–0.997, p = 0.001), tricuspid regurgitation (1.192, 1.072–1.326, p = 0.001), Risk Adjustment in Congenital Heart Surgery-1 risk grade (1.166, 1.011–1.345, p = 0.035), aortic shunt (left-to-right: 1.37, 1.005–1.867, p = 0.046; bi-directional: 1.716, 1.138–2.587, p = 0.01), atrial shunt (left-to-right: 1.407, 1.097–1.805, p = 0.007; right-to-left: 3.168, 1.944–5.163, p < 0.001; bi-directional: 1.87, 1.389–2.519, p < 0.001), ventricular level shunt (left-to-right: 0.676, 0.486–0.94, p = 0.02; bi-directional: 2.09, 1.611–2.712, p < 0.001), residual shunt (3.489, 1.502–8.105, p = 0.004), left ventricular outflow tract obstruction (3.934, 1.673–9.254, p = 0.002), right ventricular outflow tract obstruction (3.638, 1.225–10.798, p = 0.02), circulating temperature (mild hypothermia: 1.526, 95% CI: 1.205–1.934, p < 0.001; middle and low temperature: 1.738, 1.236–2.443, p = 0.001), duration of cardiopulmonary bypass (1.009, 1.006–1.012, p < 0.001), myocardial preservation using histidine-tryptophan-ketoglutarate (1.677, 1.298–2.167, p < 0.001), and mitral insufficiency (1.714, 1.239–2.37, p < 0.001) were independent risk predictors of LCOS.

Conclusions

The incidence of postoperative LCOS in CHD children remains high. Circulation temperature, myocardial preservation using histidine-tryptophan-ketoglutarate, and usage of residual shunt after surgery were independent risk predictors for LCOS.