Endobronchial ultrasound for the detection of chronic pulmonary artery thrombus

Assessment of effectiveness and safety of thrombolytic therapy to pulmonary emboli by endobronchial ultrasound-guided transbronchial needle injection

Objective

Endobronchial ultrasound-guided transbronchial needle injection (EBUS-TBNI) may effectively treat acute pulmonary embolisms (PEs). Here, we assessed the effectiveness of clot dissolution and safety of tissue plasminogen activator (t-PA) injection using EBUS-TBNI in a 1-week survival study of a porcine PE model.

Methods

Six pigs with bilateral PEs were used: 3 for t-PA injection using EBUS-TBNI (TBNI group) and 3 for systemic administration of t-PA (systemic group). Once bilateral PEs were created, each 25 mg of t-PA injection using EBUS-TBNI for bilateral PEs (a total of 50 mg t-PA) and 100 mg of t-PA systemic administration was performed on day 1. Hemodynamic parameters, blood tests, and contrast-enhanced computed tomography scans were carried out at several time points. On day 7, pigs were humanely killed to evaluate the residual clot volume in the pulmonary arteries.

Results

The average of percent change of residual clot volumes was significantly lower in the TBNI group than in the systemic group (%: systemic group 36.6 ± 22.6 vs TBNI group 9.6 ± 6.1, P < .01) on day 3. Considering the elapsed time, the average decrease of clot volume per hour at pre-t-PA to post t-PA was significantly greater in the TBNI group than in the systemic group (mm3/hour: systemic 68.1 ± 68.1 vs TBNI 256.8 ± 148.1, P < .05). No hemorrhage was observed intracranially, intrathoracically, or intraperitoneally on any contrast-enhanced computed tomography images.

Conclusions

This study revealed that t-PA injection using EBUS-TBNI is an effective and safe way to dissolve clots.

Recent advances in convex probe endobronchial ultrasound: a narrative review

Convex probe endobronchial ultrasound (CP-EBUS) has been widely used in the lymph node staging and restaging of lung tumors and the diagnosis of mediastinal diseases. Recent years have seen continuous progress in this technology. For diagnosis, elastography technology can preliminarily distinguish between benign and malignant lesions, so that reduce the number of punctures. CP-EBUS can also be used as an endoscopic ultrasound (EUS) to guide needle aspirations of liver lesions, retroperitoneal lymph nodes and left adrenal gland (LAG) lesions sometimes. Some advances help diagnosing more accurately and effectively, such as the intranodal forceps biopsy (IFB), the new type of 22G needle, the rapid on-site evaluation (ROSE) and the cancer gene methylation, etc. In addition, special advances are being made in diagnosis using artificial intelligence (AI). For treatment, CP-EBUS has yielded novel research results when applied to transbronchial needle injection (TBNI) and radioactive seed implantation in clinical cases, and blocking of the cardiac plexus in animal studies. The next-generation CP-EBUS is also ready for use in the clinic and the technology will be improving continuously. Through this review, we hope to educate clinicians on the latest uses of CP-EBUS and open up further research ideas for readers interested in this technology.

Circular RNAs in thoracic diseases

Circular RNAs (circRNAs) are a class of noncoding RNAs with continuous, covalently closed circular structures. Investigators have shown previously that circRNAs are regulators of gene expression in mammals. These tissue-specific transcripts are produced primarily by exonic or intronic sequences of housekeeping genes. Several biosynthetic models have been proposed for circRNAs, and consensus is lacking. CircRNAs are widely expressed in the cytoplasm and highly conserved, what is more, unlike other noncoding RNAs, circRNAs are relatively stable. These properties suggest special roles of circRNAs, such as microRNA (miRNA) sponges, regulators of selective splicing, or even protein-coding sequences. The expression of circRNAs is associated with many pathologic conditions; therefore, circRNAs may have utility as biomarker for the diagnosis or prediction of diseases. Authors previously have demonstrated that circRNAs can regulate the expression of a variety of disease-related miRNAs. The circRNA-miRNA-target gene interaction network regulates several pathways that inhibit or promote the occurrence of certain diseases. Based on their potential clinical relevance, circRNAs are a crucial topic of disease prevention and treatment research. Herein, we review current research regarding circRNAs and explore their potential clinical applications for thoracic diseases diagnosis and treatment.

Pathway and application value of exploration of the pulmonary artery by endobronchial ultrasound

Background

The current standard methods for detecting pulmonary artery diseases are pulmonary artery enhanced computed tomography (CT) scan and pulmonary arteriography. However, some patients cannot tolerate these procedures for various reasons. The present study aimed to investigate the feasibility and operation process of endobronchial ultrasound (EBUS) in exploring the pulmonary artery.

Methods

Based on normal contrast-enhanced chest CT images, the sites and process for exploring the pulmonary arteries were established. Then the feasibility of the exploration by the convex probe EBUS were evaluated, and roadmaps for exploration of the pulmonary arteries were drawn.

Results

Among patients who underwent pulmonary artery exploration, sonograms of the left and right pulmonary artery were obtained by the convex probe EBUS. The above-mentioned pulmonary artery branches can be positioned by means of anatomical markers under the bronchoscopic view and follow a certain route for continuous exploration. Sonograms had a certain degree of identification and can be used as an auxiliary tool for pulmonary artery exploration.

Conclusions

EBUS can be used to explore the main branches of the pulmonary artery continuously. Therefore, EBUS could be considered as a candidate for the diagnosis of pulmonary artery diseases in a selected group of patients, i.e., patient with contrast allergy or renal failure.

Endosonography of a Pulmonary Artery Obstruction in Echinococcosis

A 44-year-old woman with a history of pulmonary embolism and abdominal echinococcosis complained of sudden thoracic pain and shortness of breath. A D-dimer of 77.5 mg/l (reference ≤0.5 mg/l) was found. Chest CT scan revealed obstruction of the right lower and middle lobe pulmonary artery (PA). Anticoagulation therapy was initiated for the presumed diagnosis of recurrent pulmonary embolism. However, due to persistent symptoms of dyspnea, follow-up CT angiography of the chest was performed 3 months later. A persistent PA obstruction was found and the presumed diagnosis of embolism was questioned. Subsequently, endobronchial ultrasound (EBUS) imaging was performed to support an alternative diagnosis. EBUS imaging showed an inhomogeneous, sharply demarcated, intravascular lesion with round hypoechoic areas compatible with cysts. The diagnosis of embolism was rejected and treatment with albendazole was initiated for pulmonary echinococcosis. Echinococcosis is a parasitic disease and cystic spread in the PA is exceptional. The patient has remained stable for more than 4 years. In case of disease progression, including progressive PA obstruction or life-threatening hemoptysis, surgical resection will be considered.