Pulmonary Artery Obstruction Index and Right Ventricular Dysfunction Signs in Initial and Follow up Pulmonary Computed Tomography Angiography in Acute Pulmonary Embolism

RNA-sequencing analysis of gene expression in a rat model of acute right heart failure

Background: Acute right heart failure (RHF) is the main cause of death in patients with acute pulmonary embolism and emergent pulmonary hypertension. However, the molecular mechanisms underpinning the acute RHF and the interactions between the right (RV) and left ventricles (LVs) under the diseased condition remain unknown. Methods and results: The Sprague Dawley male rats were randomly divided into the normal control, sham, and pulmonary artery banding (PAB) groups. One hour after the PAB operation, after measuring the haemodynamic and anatomical parameters, the free walls of RV and LV were harvested to detect the differential gene expression profiling by high-throughput RNA sequencing. The results showed that the PAB lead to 50-60% obstruction of the main pulmonary artery, which was accompanied by the significant elevation in the positive rate of rise in RV pressure and the maximum RV pressure as compared to the sham group. Moreover, compared with the counterparts in the sham group, the RV and LV in the PAB group exhibited 2057 differentially expressed genes (DEGs, 1159 upregulated and 898 downregulated) and 1196 DEGs (709 upregulated and 487 downregulated), respectively (DEG criteria: |log₂ fold change| ≥1, q value ≤0.05). In comparison to the sham group, the enriched pathways in the PAB group include nuclear factor-κB signalling pathway, extracellular matrix-receptor interaction, and nucleotide oligomerization domain-like receptor signalling pathway. Conclusions: The PAB rat model exhibited the haemodynamic and gene expression changes in the RV that lead to acute RHF. Further, the acute RHF induced by pressure overload also caused gene expression changes in the LV, suggesting the molecular interactions between the RV and LV under the diseased condition.

The Association between the Pulmonary Arterial Obstruction Index and Atrial Size in Patients with Acute Pulmonary Embolism

Purpose

Pulmonary embolism (PE) is a common and potentially fatal form of venous thromboembolism. The aim of this study is to investigate the association between the pulmonary arterial obstruction index and atrial size in patients with acute pulmonary embolism.

Basic Procedure

The study consisted of 86 patients with clinical symptoms of PE. Out of 86 individuals, 50 patients were diagnosed with PE and considered as the patient group. The others were considered as the control group. All patients were scanned by a multidetector CT scanner. Using the radiology workstation, an expert radiologist calculated the left atrium (LA) and right atrium (RA) areas from planimetric measurements obtained from free-hand delineation of the atrial boarders using an electronic pen. Quantitative volumetric measurements of LA and RA were obtained from original axial images.

Main Findings

There were 25 males and 25 females with PE, who had a mean age of 58 years. There was not a significant difference in the positive history of diabetes mellitus, hypertension, asthma, chronic obstructive pulmonary diseases, ischemic heart disease, and smoking between patients and control group. There was a significant negative correlation between almost all LA measurements and the PAOI. RA area and volume had the highest area under the curves for recognizing larger clot burden.

Principal Conclusions

A higher clot load is associated with a smaller LA size and increased RA/LA ratios, measured with CTPA. Atrial measurements are correlated with POAI, and they could be used as sensitive parameters in predicting heart failure in patients with PE.