Evaluation of Right Ventricular Function and Dyssynchrony in a Dog Model of Acute Pulmonary Embolism: Diagnostic Utility and Reversibility

A new noninvasive evaluation method of pulmonary thromboembolism in rabbits-pulmonary transit time

BACKGROUND AND AIM

Pulmonary thromboembolism (PTE) is a common cause of cardiovascular death worldwide. Due to its nonspecific clinical symptoms, PTE is easy to be missed or misdiagnosed. Pulmonary transit time (PTT) is a noninvasive cardiopulmonary hemodynamic index, which is the time required for a blood sample to pass through pulmonary circulation. This study is aim to establish a rabbit PTE model using auto-thrombus, evaluating the dynamic changes in a rabbit's heart structure and function at multiple time points before and after modeling by echocardiography and exploring the application value of PTT obtained by contrast enhanced ultrasound (CEUS) in evaluating a PTE model.

METHODS

Twenty-four healthy rabbits were intubated by femoral vein puncture to establish the PTE model. Echocardiography was performed before embolization, 2 h, 24 h, 3 days, 5 days, and 7 days after embolization to obtain conventional ultrasonic parameters. Then, CEUS was performed to obtain the PTT.

RESULTS

Seventh day after modeling, nineteen rabbits were alive. Compared with pre-modeling, right heart parameters and heart rate in echocardiography were significantly impaired in the acute phase (2 and 24 h after modeling) and gradually returned to normal in the compensatory phase (3, 5, and 7 days after modeling). In contrast with conventional ultrasound parameters, PTT and nPTT revealed a gradually increasing trend at each time point. Receiver operating characteristic (ROC) curve analysis revealed with an extension of molding time, the area under the curve (AUC) of (n)PTT is larger and larger.

CONCLUSIONS

Right heart parameters obtained using conventional echocardiography can accurately indicate changes in the structure and function of the right heart during the acute phase of PTE, while (n)PTT measured by CEUS continues to extend during the acute and compensatory phases of PTE. Therefore, PTT (nPTT) obtained by CEUS is a useful clinical indicator for the diagnosis of PTE and can be utilized as a supplement to conventional echocardiography parameters.

Right Ventricular Longitudinal Strain-Related Indices in Acute Pulmonary Embolism

Pulmonary embolism (PE) is correlated with serious morbidity and mortality. Efforts have been made to establish and validate mortality predictive scores based mainly on clinical parameters. Patients with PE and traditional indices of echocardiographic right ventricular (RV) dysfunction or pressure overload have a higher probability of a worse outcome. During the last two decades, studies regarding the use of two-dimensional speckle-tracking echocardiography (2DSTE) and its derived indices in the setting of acute PE have been conducted. In this comprehensive review of the literature, we aimed to summarize these studies. Safe conclusions and comparisons among the reviewed studies are prone to statistical errors, mainly because the studies published were heterogenous in design, different 2DSTE-derived parameters were tested, and different clinical outcomes were used as endpoints. Nonetheless, RV strain indices and, more commonly, regional longitudinal strain of the RV free wall have shown a promising correlation with mortality, assisting in the differential diagnosis between PE and other acute or chronic disorders.

Right ventricular dyssynchrony for the prediction of prognosis in patients with systemic lupus erythematosus-aaociated pulmonary arterial hypertension: a study with two-dimensional speckle tracking

Pulmonary arterial hypertension (PAH) is a common complication of systemic lupus erythematosus (SLE), and PAH can cause right ventricle (RV) remodel and dyssynchrony. The aim of this study was to explore the value of RV dyssynchrony in predicting adverse clinical events in patients with systemic lupus erythematosus-aaociated pulmonary arterial hypertension (SLE-PAH) using two-dimensional speckle tracking echocardiography (2D-STE). A total of 53 patients with SLE-PAH were enrolled in this study. The dyssynchrony of the RV (RV-SD6) was evaluated by 2D-STE. The clinical data of all participants were collected, and routine cardiac function parameters were measured by two-dimensional echocardiography, and analyzed for their correlation with RV-SD6. The predictive value of RV-SD6 in clinical adverse event was evaluated. RV-SD6 was negatively correlated with RV-FLS, RV-FAC, and TAPSE (r = - 0.788, r = - 0.363 and r = - 0.325, respectively, all P < 0.01), while the correlation with RV-FLS was the strongest. linear regression analysis showed that RV-FLS was an independent risk factor for RV-SD6 (β = - 1.40, 95% CI - 1.65 ~ - 1.14, P < 0.001). Cox regression analysis showed that RV-SD6 was a predictor with clinical adverse events (HR = 1.03, 95% CI 1 ~ 1.06, P < 0.05). RV-SD6 was highly discriminative in predicting clinical adverse events (AUC = 0.764), at a cutoff of 51.10 ms with a sensitivity of 83.3% and specificity of 68.3%. RV-FLS was negatively correlated with RV-SD6 and was an independent risk factor for it. RV-SD6 can serve as an indicator for predicting the occurrence of adverse clinical events in SLE-PAH patients, with high sensitivity and specificity.