Pulmonary Arteriovenous Pressure Gradient and Time-Averaged Mean Velocity of Small Pulmonary Arteries Can Serve as Sensitive Biomarkers in the Diagnosis of Pulmonary Arterial Hypertension: A Preclinical Study by 4D-Flow MRI

(1) Background: Pulmonary arterial hypertension (PAH) is a serious condition that is associated with many cardiopulmonary diseases. Invasive right heart catheterization (RHC) is currently the only method for the definitive diagnosis and follow-up of PAH. In this study, we sought a non-invasive hemodynamic biomarker for the diagnosis of PAH. (2) Methods: We applied prospectively respiratory and cardiac gated 4D-flow MRI at a 9.4T preclinical scanner on three different groups of Sprague Dawley rats: baseline (n = 11), moderate PAH (n = 8), and severe PAH (n = 8). The pressure gradients as well as the velocity values were analyzed from 4D-flow data and correlated with lung histology. (3) Results: The pressure gradient between the pulmonary artery and vein on the unilateral side as well as the time-averaged mean velocity values of the small pulmonary arteries were capable of distinguishing not only between baseline and severe PAH, but also between the moderate and severe stages of the disease. (4) Conclusions: The current preclinical study suggests the pulmonary arteriovenous pressure gradient and the time-averaged mean velocity as potential biomarkers to diagnose PAH.

Maladaptive Pulmonary Vascular Responses to Chronic Sustained and Chronic Intermittent Hypoxia in Rat

Chronic sustained hypoxia (CSH), as found in individuals living at a high altitude or in patients suffering respiratory disorders, initiates physiological adaptations such as carotid body stimulation to maintain oxygen levels, but has deleterious effects such as pulmonary hypertension (PH). Obstructive sleep apnea (OSA), a respiratory disorder of increasing prevalence, is characterized by a situation of chronic intermittent hypoxia (CIH). OSA is associated with the development of systemic hypertension and cardiovascular pathologies, due to carotid body and sympathetic overactivation. There is growing evidence that CIH can also compromise the pulmonary circulation, causing pulmonary hypertension in OSA patients and animal models. The aim of this work was to compare hemodynamics, vascular contractility, and L-arginine-NO metabolism in two models of PH in rats, associated with CSH and CIH exposure. We demonstrate that whereas CSH and CIH cause several common effects such as an increased hematocrit, weight loss, and an increase in pulmonary artery pressure (PAP), compared to CIH, CSH seems to have more of an effect on the pulmonary circulation, whereas the effects of CIH are apparently more targeted on the systemic circulation. The results suggest that the endothelial dysfunction evident in pulmonary arteries with both hypoxia protocols are not due to an increase in methylated arginines in these arteries, although an increase in plasma SDMA could contribute to the apparent loss of basal NO-dependent vasodilation and, therefore, the increase in PAP that results from CIH.

Pulmonary embolism in the COVID-19 pandemic era: Importance of bedside electrocardiography, echocardiography and use of Tenecteplase.

Pulmonary embolism is a blockage in one of the pulmonary arteries in the lungs. Globally, it is the third most frequent acute cardiovascular syndrome behind myocardial infarction and stroke. This is a 43-yearold Nigerian diabetic man who had liposuction three weeks before presenting with sudden onset breathlessness, productive cough, chest pain, fever, inability to complete a sentence and inability to carry out his normal daily activities during this coronavirus 2019 (COVID-19) pandemic. He was tachypneic, tachycardic, hypotensive with rapidly dropping oxygen saturation (84%-86%, 80%-84%). This presented a diagnostic challenge which was rapidly resolved with bedside electrocardiography and echocardiography. A diagnosis of pulmonary embolism was sustained. Subsequent SARS-COV-2 PCRbased test was negative. He was successfully managed with an antithrombotic agent, tenecteplase, without any adverse events. Keywords: COVID-19, pulmonary embolism, tenecteplase, electrocardiography, echocardiography

Experience in treatment of patients with arterial and venous thrombosis with proven COVID-19

Background. COVID-19 is represented by a large number of different phenotypes, ranging from asymptomatic progress to the development of severe multiple organ dysfunction syndrome. The mechanisms of development of multiple organ dysfunction syndrome are multifactorial, including hypercoagulation with the formation of blood clots. They are often diagnosed as thrombotic complications with detection of blood clots not only in the veins and pulmonary arteries, but also in the heart and main arteries. An observational study shows that the incidence of venous and arterial thrombosis is as high as 31% in patients with COVID-19 pneumonia. However, large studies have not yet been conducted.Aim. To generalize and analyze our own observations of the clinical course of patients with thrombosis and COVID-19.Methods. The study included 5 male patients who had arterial and venous thrombosis and COVID-19 positive test. Results The experience of treatment of 5 patients with COVID-19 with arterial and venous thrombosis was analyzed. All patients showed characteristic changes in the coagulogram. The patient who, upon admission, had a negative test for COVID-19, and characteristic changes in the coagulogram appeared on the day of recurrent thrombosis, was of greatest interest. All patients received standard treatment and were discharged with improvement after testing negative for COVID-19.Conclusion. Generalization of the clinical course of patients with COVID-19 and thrombosis of various vascular regions allowed us to develop treatment tactics for these groups of patients.

RECOMMENDATIONS FOR SPIRAL PULMONARY ARTERIOPLASTY

Case Video Summary: This video demonstrates the principle of spiral PA plasty whereby the length of branch pulmonary arteries can be increased simultaneous to the increase in diameter by using a patch that is anastomosed spirally around the vessels.