Pictorial review of the pulmonary vasculature: from arteries to veins

Intraoperative Acute Cardiac Tamponade as a Result of Intracardiac Perforation Requiring Emergency Continuous Pericardiocentesis and Open Sternotomy: A Case Report and Literature Review of a Rare but Fatal Complication

Intraoperative acute cardiac tamponade associated with iatrogenic intracardiac perforation from percutaneous interventional cardiac procedures is a rare but potentially catastrophic complication. We report a case of intraoperative acute hemopericardium caused by a left atrial (LA) perforation resulting in cardiac tamponade in a patient undergoing a baffling procedure for the correction of two anomalous pulmonary veins draining into her superior vena cava (SVC) that required continuous pericardiocentesis with autologous blood transfusion via the femoral vein and an emergency intraoperative transfer from the interventional cardiology cath lab to the cardiac operating room for an open sternotomy and primary repair. An 86-year-old female with known right-ventricular (RV) failure with preserved ejection fraction (left ventricular ejection fraction (LVEF): 50-55% on transesophageal echocardiography (TEE) one week prior) and atrial fibrillation was admitted for her third heat failure exacerbation in two months despite being adherent to her aggressive diuresis medication regimen. Upon her readmission and due to her symptomatic and seemingly refractory heart failure, the patient underwent a cardiac computer tomography (CT) with 3D reconstruction that showed previously undiagnosed partial anomalous pulmonary venous return (PAPVR) of two of her four pulmonary veins aberrantly draining into the SVC. This anatomic pathology was deemed to be the likely etiology of her repeated episodes of recurring heart failure exacerbations, shortness of breath, peripheral edema, and fatigue. The patient was counseled and consented to a percutaneous baffle of the two anomalous veins to redirect more of the returning pulmonary venous blood away from the SVC and to the LA. While under general endotracheal anesthesia (GETA) with a TEE in place during the procedure, the patient suddenly developed acute hypotension, tachycardia, and a reduction in expired carbon dioxide (EtCO2) was noted quickly followed by evidence of a rapidly accumulating hemopericardium on TEE. Cardiothoracic surgery was urgently consulted to the interventional cardiology cath lab while the patient underwent an emergency pericardiocentesis that momentarily alleviated her hemodynamic instability, cardiac tamponade physiology, and deteriorating overall clinical picture. While performing continuous pericardiocentesis with autologous return of the aspirated blood via femoral venous access the patient was urgently transported to the cardiac operating room and prepped for emergency sternotomy for primary repair of the LA. Following primary repair via sternotomy, multiple drains were placed and the thoracic cavity was closed with wires. The patient was immediately transported to the surgical intensive care unit (SICU) intubated, mechanically ventilated, and sedated. During this time, the patient progressively required additional vasoactive and inotropic agents to support her mean arterial pressure (MAP), and following a multidisciplinary discussion with the patient's family regarding her goals of care, the decision was made to withdraw further resuscitation efforts and the patient expired four hours later.

Pulmonary artery pseudoaneurysm arising from primary lung neoplasm: A proposed mechanism

Pulmonary artery pseudoaneurysms (PAPs) are rare and life-threatening occurrences. We present a 57-year-old male patient with squamous cell lung cancer, who presented with hemoptysis. Bronchoscopy did not reveal ongoing bleeding. Imaging showed a left lower lobe tumor, a cavitary lesion communicating with the bronchus, and a pulmonary artery pseudoaneurysm. Successful embolization of the originating segmental branch of the pulmonary artery was performed. The pathogenesis of PAPs associated with primary lung malignancies remains poorly understood. We propose a four-step mechanism involving primary tumor expansion, central cavitary necrosis, direct arterial invasion, inflammatory response, vessel wall damage, pseudoaneurysm formation, and subsequent filling of the former cavitary lesion. This case emphasizes the importance of considering PAPs in primary lung malignancies, particularly in male patients with squamous cell pathology. Understanding the proposed pathogenic mechanism could lead to early detection, prompt intervention, and improved outcomes.

Distal Arch Aneurysm Discovered With Dysphagia

A 64-year-old man sought medical attention from a family physician, expressing concerns about dysphagia. Recognizing the complexity of the symptoms, the family physician promptly engaged the expertise of an attending physician at a regional hospital to ensure accurate diagnosis and management. Plain computed tomography (CT) revealed a space-occupied lesion located posterior to the trachea. Although mediastinal tumor was suspected at first, contrast-enhanced CT revealed a distal arch aneurysm that compressed the esophagus. The patient underwent total arch replacement, and the postoperative course was uneventful.

The Vasculature in Pulmonary Fibrosis

Purpose of Review

The current paradigm of idiopathic pulmonary fibrosis (IPF) pathogenesis involves recurrent injury to a sensitive alveolar epithelium followed by impaired repair responses marked by fibroblast activation and deposition of extracellular matrix. Multiple cell types are involved in this response with potential roles suggested by advances in single-cell RNA sequencing and lung developmental biology. Notably, recent work has better characterized the cell types present in the pulmonary endothelium and identified vascular changes in patients with IPF.

Recent Findings

Lung tissue from patients with IPF has been examined at single-cell resolution, revealing reductions in lung capillary cells and expansion of a population of vascular cells expressing markers associated with bronchial endothelium. In addition, pre-clinical models have demonstrated a fundamental role for aging and vascular permeability in the development of pulmonary fibrosis.

Summary

Mounting evidence suggests that the endothelium undergoes changes in the context of fibrosis, and these changes may contribute to the development and/or progression of pulmonary fibrosis. Additional studies will be needed to further define the functional role of these vascular changes.

Mapping the Distribution of Special Structured Pulmonary Vasculatures in the Dromedary Camel (Camelus dromedarius): Histological and Histochemical Study

Dromedary camel (Camelus dromedarius) is adapted to survive the harsh environments. It has some key adaptation peculiarities in various organs. In this study, we aimed to map the distribution pattern of unique regulatory devices along the course of the pulmonary vessels using histological and histochemical analyses. Arteries with variable wall thickness and spirally oriented course were recorded within the adventitia of the main pulmonary artery. Throttle arteries and glomus bolsters were found within the wall of the lobar pulmonary artery. The bronchial artery was located within the wall of all bronchi reaching the subsegmental branches and it had elastic longitudinal muscular intima bolsters. Arteries with double muscular media were demonstrated in the pulmonary pleura. These bolsters are suggested to play a complicated role that allows for hemodynamic, humeral, and thermoregulatory activities. The lumen of some subsegmental pulmonary veins revealed occasional constrictions arising from the corresponding muscular pad-like protrusions of the tunica media. These veins may possess occlusive or constrictive mechanisms and their obstruction induces engorgement of the associated capillary bed in addition to restricting venous outflow. Collectively, these data strongly recommend a crucial role for the special regulatory devices in preserving the camel pulmonary function in the harsh desert environment.

Application of Multi-Slice Spiral CT in the Evaluation of Diffuse Lung Diseases

This article analyzes the manifestations, characteristics, and significance of multi-slice spiral CT for diffuse lung disease, and evaluates the diagnostic value of multi-slice CT multi-directional reconstruction for diffuse lung disease. After performing multi-slice spiral CT examination on the patient and collecting relevant data, the characteristic multi-slice CT imaging findings of diffuse lung disease were determined by statistical analysis. Diffuse lung disease is representative in multi-slice spiral CT image imaging manifestations of the disease include multiple disseminated small nodules, multiple voids, ground glass shadows, and lung consolidation. And analyze the correlation of image performance, and then use statistical methods to analyze and evaluate the value of multi-slice spiral CT characteristic images in the diagnosis of diffuse lung disease, and analyze the characteristics of these characteristic multi-slice CT image appearances. The use of high-resolution CT to screen the characteristic CT imaging findings of the same research object, and then to perform a statistical analysis of the diagnostic differences with multi-slice spiral CT, further confirmed the importance of multi-slice CT for diffuse lung disease Diagnostic value. Studies have shown that multi-slice CT imaging technology is of great significance in the evaluation of diffuse lung diseases.

Partial anomalous pulmonary venous return after orthotopic heart transplantation case report

Background

Partial anomalous pulmonary venous return (PAPVR) is a congenital heart defect. Reports of repair and treatment in pediatric cases have been published, but incidence of PAPVR in adults is not common. To our knowledge, there has not been a diagnosis of left-sided PAPVR after a heart transplant an in adult patient.

Case presentation

A 62-year-old patient with ischemic cardiomyopathy and systolic heart failure underwent orthotopic heart transplantation. The immediate post-operative course was remarkable for an elevated cardiac index and pulmonary artery pressures as well as decreased systemic vascular resistance. The post-operative echocardiogram did not reveal an intra-cardiac shunt. However, computed tomographic angiography (CTA) showed a left superior pulmonary vein draining into the innominate vein. Operative repair of the left superior pulmonary venous connection to the left atrial appendage was completed under cardiopulmonary bypass with beating heart. Her hemodynamics improved immediately, and she had an unremarkable postoperative course.

Conclusions

While uncommon, any patient with a high cardiac output and abnormal hemodynamics after heart transplant should be evaluated for the existence of a shunt. While not a part of all traditional preoperative imaging protocols, a chest CTA should be considered if PAPVR is suspected as it can both diagnose the condition and enable a plot of the corrective course of surgical action.

Structural and hemodynamic properties of murine pulmonary arterial networks under hypoxia-induced pulmonary hypertension

Detection and monitoring of patients with pulmonary hypertension, defined as a mean blood pressure in the main pulmonary artery above 25 mmHg, requires a combination of imaging and hemodynamic measurements. This study demonstrates how to combine imaging data from microcomputed tomography images with hemodynamic pressure and flow waveforms from control and hypertensive mice. Specific attention is devoted to developing a tool that processes computed tomography images, generating subject-specific arterial networks in which one-dimensional fluid dynamics modeling is used to predict blood pressure and flow. Each arterial network is modeled as a directed graph representing vessels along the principal pathway to ensure perfusion of all lobes. The one-dimensional model couples these networks with structured tree boundary conditions representing the small arteries and arterioles. Fluid dynamics equations are solved in this network and compared to measurements of pressure in the main pulmonary artery. Analysis of microcomputed tomography images reveals that the branching ratio is the same in the control and hypertensive animals, but that the vessel length-to-radius ratio is significantly lower in the hypertensive animals. Fluid dynamics predictions show that in addition to changed network geometry, vessel stiffness is higher in the hypertensive animal models than in the control models.

Structural and functional characteristics of the special regulatory devices in the peripheral pulmonary circulation in rabbits

The present study intended to describe in detail the several blood vessels harboring special regulatory devices in rabbit's pulmonary tissue using light and electron microscopy and immuno-histochemistry. Numerous throttle arteries were recorded within the adventitia of the segmental and sub-segmental bronchi and within pulmonary pleura. These arteries showed characteristic narrow or obliterated lumens and some of them bear longitudinal muscular intimal bolsters. For the first time, TEM revealed some structural modifications of the vascular endothelial cells of these arteries indicating that they become more activated to perform some additional functions. Arteriovenous anastomoses (AVAs) including direct shunt vessels and glomus organs were also recognized. Direct arteriovenous shunts appeared as small connecting devices communicating between small arteries and small veins while glomus organs consisted of the tortuous glomus vessels and the related afferent and efferent vessels. Several arteries and veins showing unique unusual structural characteristics were also described. For the first time, serotonin (5-HT) was strongly expressed in the vascular endothelium and muscle fibers of throttle arteries, in glomus cells of the glomus vessels, and in vascular endothelium of some veins and venules of special structure. The exact role of 5-HT is still unknown and further investigations are required to determine the types and distribution of 5-HT receptors present in these vascular devices. We concluded that these special vascular devices can play a critical role in controlling blood flow and pressure in the peripheral pulmonary circulation; however, the exact physiological mechanisms by which they work or are controlled remain unknown providing a ripe area for further investigation.