Case Reports: Bronchial Mucosal Vasculature Is Also Involved in the Acute Vascular Distress Syndrome of COVID-19

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which targets the pulmonary vasculature is supposed to induce an intrapulmonary right to left shunt with an increased pulmonary blood flow. We report here what may be, to the best of our knowledge, the first videoendoscopic descriptions of an hypervascularization of the bronchial mucosa in two patients hospitalized for coronavirus disease 2019 (COVID-19) pneumonia.Cases Presentation: Two patients, 27- and 37-year-old, were addressed to our Pneumology department for suspicion of COVID-19 pneumonia. Their symptoms (fever, dry cough, and dyspnoea), associated to pulmonary ground glass opacities on thoracic CT, were highly suggestive of a COVID-19 disease despite repeated negative pharyngeal swabs RT-PCR. In both patients, bronchoscopy examination using white light was unremarkable but NBI bronchoscopy revealed a diffuse hypervascularization of the mucosa from the trachea to the sub-segmental bronchi, associated with dilated submucosal vessels. RT-PCR performed in bronchoalveolar lavage (BAL) confirmed the presence of Sars-CoV-2.Conclusions: These two case reports highlight the crucial importance of the vascular component of the viral disease. We suggest that such bronchial hypervascularization with dilated vessels contributes, at least in part, to the intrapulmonary right to left shunt that characterizes the COVID-19 related Acute Vascular Distress Syndrome (AVDS). The presence of diffuse bronchial hypervascularization in the context of COVID-19 pandemic should prompt the search for Sars-CoV-2 in BAL samples.

Factors Influencing Reintervention Following Ductal Artery Stent Implantation for Ductal-Dependent Pulmonary Blood Flow: Results From the Congenital Cardiac Research Collaborative

Background: Stenting of the patent ductus arteriosus (PDA) is an established palliative option for infants with ductal-dependent pulmonary blood flow. Following initial palliation, reintervention on the PDA stent is common, but risk factors have not been characterized. Methods: Infants with ductal-dependent pulmonary blood flow palliated with PDA stent between 2008 and 2015 were reviewed within the Congenital Cardiac Research Collaborative. Rates and risk factors for reintervention were analyzed. Results: Among 105 infants who underwent successful PDA stenting, 41 patients (39%) underwent a total of 53 reinterventions on the PDA stent, with all but one occurring within 6 months of the initial intervention. Stent redilation constituted the majority of reintervention (n=35; 66%) followed by additional stent placement (n=11; 21%) and surgical shunt placement (n=7; 13%). The majority of reintervention was nonurgent, and there were no deaths during the reintervention procedure. All but one reintervention occurred within 6 months of the initial procedure. On univariate analysis, risk factors for reintervention included anticipated single-ventricle physiology, lack of prior balloon pulmonary valvuloplasty, use of drug-eluting stent, and increased ductal tortuosity. Conclusions: In infants with ductal-dependent pulmonary blood flow palliated with PDA stent implantation, reintervention is common, can be performed safely, and is associated with both anatomic/procedural factors and anticipated final physiology.

MR lung perfusion measurements in adolescents after congenital diaphragmatic hernia: correlation with spirometric lung function tests

Objectives To evaluate whether lung perfusion continues to be reduced in 10-year-old children after congenital diaphragmatic hernia (CDH) and whether lung perfusion values correlate with spirometric lung function measurements. Methods Fifty-four patients after CDH repair received dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI)-based lung perfusion measurements at the age of 10 years (10.2 ± 1.0 years). Additionally, a control group of 10 children has been examined according to the same protocol. Lung spirometry was additionally available in 43 patients of the CDH group. A comparison of ipsilateral and contralateral parameters was performed. Results Pulmonary blood flow (PBF) was reduced on the ipsilateral side in CDH patients (60.4 ± 23.8 vs. 93.3 ± 16.09 mL/100 mL/min; p < 0.0001). In comparison to the control group, especially the ratio of ipsilateral to contralateral, PBF was reduced in CDH patients (0.669 ± 0.152 vs. 0.975 ± 0.091; p < 0.0001). There is a positive correlation between ipsilateral pulmonary blood flow, and spirometric forced 1-s volume (r = 0.45; p = 0.0024). Conclusions Pulmonary blood flow impairment persists during childhood and correlates with spirometric measurements. Without the need for ionizing radiation, MRI measurements seem promising as follow-up parameters after CDH. Key Points • Ten-year-old children after congenital diaphragmatic hernia continue to show reduced perfusion of ipsilateral lung. • Lung perfusion values correlate with lung function tests after congenital diaphragmatic hernia.

Pre-procedural CT imaging aids neonatal PDA stenting for ductal-dependent pulmonary blood flow with reduction in overall procedural morbidity

Patent ductus arteriosus stenting for ductal-dependent pulmonary blood flow is a technically challenging neonatal procedure to maintain a stable pulmonary circulation. Pre-procedural computed tomography imaging aids in outlining ductal origin, insertion, size, course and curvature. Computed tomography imaging may add value to procedural outcomes and reduce overall procedural morbidity in neonatal patent ductus arteriosus stenting. We conducted a single centre retrospective chart review of neonates with ductal-dependent pulmonary blood flow who underwent patent ductus arteriosus stenting between January 1, 2014 and June 31, 2020. We compared patients variables between patients who underwent pre-procedural computed tomography imaging to those who did not. A total of 64 patients were referred for patent ductus arteriosus stenting with 33 (52%) obtaining pre-procedural computed tomography imaging. Average age [19 days; range 1–242 days (p = 0.85)] and weight [3.3 kg (range 2.2–6.0 kg; p = 0.19)] was not significantly different between the groups. A diagnosis of pulmonary atresia was made in 42 out of 64 (66%) patients prior to patent ductus arteriosus stenting. The cohort with pre-intervention computed tomography imaging had a significant reduction in the total number of access sites (1.2 versus 1.5; p = 0.03), contrast needed (5.9 versus 8.2 ml/kg; p = 0.008), fluoroscopy (20.7 versus 38.8 minutes; p = 0.02) and procedural time (83.4–128.4 minutes; p = 0.002) for the intervention. There was no significant difference in radiation burden between the groups (p = 0.35). Pre-procedural computed tomography imaging adds value by aiding interventional planning for neonatal patent ductus arteriosus stenting. A statistically significant reduction in the number of access sites, contrast exposure, as well as fluoroscopic and procedural time was noted without significantly increasing the cumulative radiation burden.

Blood Clotting Decreases Pulmonary Circulation during the Coronavirus Disease

Spontaneous blood clotting in pulmonary circulation caused by thrombo-inflammation is one of the main mortality causes during the COVID-19 disease. Blood clotting leads to reduced pulmonary circulation and blood oxygenation. Lung inflammation can be evaluated with noninvasive diagnostic techniques. However, the correlation of the severity of the inflammation with the pulmonary blood flow has not been established. To address this question, in this work, we develop a multiscale model taking into account the interaction of a local model of thrombus growth with 1D hemodynamics in a vessel network. Flux reduction depending on the level of lung obstruction is evaluated. In particular, the model obtains that an obstruction level of 5% leads to a 12% reduction of blood flux. The suggested approach can be used to investigate the interaction of blood clotting and flow not only in the pulmonary network but also in other complex vessel networks.

Standard CPR versus interposed abdominal compression CPR in shunted single ventricle patients: comparison using a lumped parameter mathematical model

Introduction: Cardiopulmonary resuscitation (CPR) in the shunted single-ventricle population is associated with poor outcomes. Interposed abdominal compression-cardiopulmonary resuscitation, or IAC-CPR, is an adjunct to standard CPR in which pressure is applied to the abdomen during the recoil phase of chest compressions. Methods: A lumped parameter model that represents heart chambers and blood vessels as resistors and capacitors was used to simulate blood flow in both Blalock-Taussig-Thomas and Sano circulations. For standard CPR, a prescribed external pressure waveform was applied to the heart chambers and great vessels to simulate chest compressions. IAC-CPR was modelled by adding phasic compression pressure to the abdominal aorta. Differential equations for the model were solved by a Runge-Kutta method. Results: In the Blalock-Taussig-Thomas model, mean pulmonary blood flow during IAC-CPR was 30% higher than during standard CPR; cardiac output increased 21%, diastolic blood pressure 16%, systolic blood pressure 8%, coronary perfusion pressure 17%, and coronary blood flow 17%. In the Sano model, pulmonary blood flow during IAC-CPR increased 150%, whereas cardiac output was improved by 13%, diastolic blood pressure 18%, systolic blood pressure 8%, coronary perfusion pressure 15%, and coronary blood flow 14%. Conclusions: In this model, IAC-CPR confers significant advantage over standard CPR with respect to pulmonary blood flow, cardiac output, blood pressure, coronary perfusion pressure, and coronary blood flow. These results support the notion that single-ventricle paediatric patients may benefit from adjunctive resuscitation techniques, and underscores the need for an in-vivo trial of IAC-CPR in children.