Pulmonary Perfusion Research Articles

Involvement of HIF1 stabilization and VEGF signaling modulated by Grx-1 in murine model of bronchopulmonary dysplasia.

Hypoxia inducible factor (HIF)-1α could be stabilized by Grx1 deletion, which is implicated critical in the pathogenesis of bronchopulmonary dysplasia (BPD). Until now, the stabilization of HIF-1α by glutathionylation to regulate the pulmonary microcirculation in BPD is not well addressed. In this study, we investigated whether the HIF-1α stabilization modulated by Grx1 ablation could ameliorate the pathological changes in the mouse model of BPD, including angiogenesis and alveolar formation. We found that depletion of Grx1 increased levels of GSH-protein adducts, which was associated with the improvement in the numbers of alveoli, the capillary density in the pulmonary microcirculation and the survival rate in the littermates with hyperoxic exposure. Grx1 ablation could promote HIF-1α glutathionylation by increasing GSH adducts to stabilize HIF-1α and to induce VEGF-A production in the lung tissue. The above phenotype of capillary density and VEGF-A production was removed by the pharmacological administration of YC-1, the HIF-1α inhibitor, suggesting the HIF-1α dependent manner for pulmonary microcirculatory perfusion. These data indicate that HIF-1α stabilization plays an critical role in modification pulmonary microcirculatory perfusion, which is associated with the pathological damage under hyperoxic conditions, suggesting that targeting with HIF-1α stabilization should be a potential clinical and therapeutic strategy for BPD treatment.

Preliminary study on the short-term changes of pulmonary perfusion after a single balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension.

Little is known about immediate responses of blood perfusion to the balloon pulmonary angioplasty (BPA) procedure. To investigate the changes in pulmonary perfusion of balloon-dilated vessels and untreated vessels with before, immediately after a single BPA and at follow-up. Retrospective single-center cohort study. Patients who had chronic thromboembolic pulmonary hypertension (CTEPH) and completed the pulmonary perfusion single photon emission computed tomography (SPECT) imaging before, immediately after BPA and at follow-up were included. We evaluated the perfusion defects of both-lung, BPA target (balloon dilated) and non-target (untreated) vessel segments according to Begic 3-point scale in each lung segment. Forty patients (40 BPA procedures) were included and were given next BPA after 89 (62-125) days. The hemodynamic parameters including mPAP, PVR, and RAP were significantly improved after a single BPA. Visual scoring results of pulmonary perfusion imaging in 40 BPAs showed the perfusion defect scores of target vessels reduced from 5.6 ± 2.6 to 4.2 ± 2.2 (p < 0.001) immediately after BPA, and then further diminished to 3.1 ± 1.9 (p < 0.001) at follow-up. While in the non-target vessels, the post-BPA perfusion defect scores did not change significantly (13.4 ± 4.7 versus 12.8 ± 4.6, p = 0.182), but tended to decrease at follow-up (12.2 ± 4.2). However, there were 17 BPAs of which the post-BPA perfusion defect scores of non-target vessels increased significantly (p < 0.001), but decreased at follow-up. In addition to improving the blood perfusion of target vessels, BPA also has a certain effect on the perfusion of some non-target vessels.

Model-less Perfusion Analysis using Deep Learning Framework

Among the various methods of analyzing pulmonary perfusion, the “with-model method” leads to large analysis errors when the model does not match the characteristics of the lesion. On the other hand, the deconvolution method of the “without-model method” is supposed to estimate the response relationship between a particular input waveform and the output waveform, i.e., the impulse response. However, the actual deconvolution method was not strictly “without-model method” because a model function was fitted in the calculation process. In this study, we propose the “Convolution Method” to estimate blood flow dynamics without using a specific model. Specifically, it “convolves the impulse response with the input waveform and updates the impulse response to minimize the error between the convolved waveform and the observed waveform. In Experiment 1, we analyzed waveforms assuming Delay and Dispersion, which have been considered difficult to analyze, and compared the conventional and proposed methods. In Experiment 2, blood flow analysis was performed on a patient with a left pulmonary artery defect. The results confirmed that the proposed method has high convergence, is independent of the input waveform, and can analyze even in the presence of vascular stenosis. It was also confirmed that it can analyze multi-input systems, and that it produces results consistent with medical findings even in patients with left pulmonary artery defects.

Surgical pulmonary embolectomy: state of the art.

Acute pulmonary embolism is a significant cause of morbidity and mortality. Patients in life-threatening conditions require timely and effective interventions to improve pulmonary perfusion. The indications for surgical embolectomy in the thrombolysis era have been limited. This article discusses surgical techniques and outlines the position of surgical embolectomy concerning other treatment modalities.

CHANGES IN THE DIFFUSION CAPACITY OF THE LUNGS AND THE TRANSFER COEFFICIENT IN PATIENTS WITH PULMONARY TUBERCULOSIS

Introduction. The study of the diffusion lung capacity (DLCO) shows the conditions of oxygen transport from the alveolar air into the blood of the pulmonary capillaries. The features of changes in the parameters of pulmonary gas exchange in patients with pulmonary tuberculosis (PT) have not been sufficiently studied. Materials and methods. 374 patients with verified PT underwent a study of the pulmonary function including DLCO and the transfer coefficient of carbon monoxide DLCO/VA, computed tomography and perfusion scintigraphy of the lungs. Results. The pulmonary gas exchange depends on the duration of PT, the volume of a specific lesion, the severity of disorders of pulmonary perfusion, including in the lung without foci of tuberculous lesions. In 23% of patients, a decrease in the transfer coefficient was observed at normal DLCO values, which indicates significant alveolar-capillary damage. Conclusion. When assessing pulmonary gas exchange in patients with pulmonary tuberculosis, it is necessary to estimate not only DLCO, but also on the transfer coefficient of carbon monoxide - DLCO/VA.

Pathophysiology and Clinical Meaning of Ventilation-Perfusion Mismatch in the Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) remains an important clinical challenge with a mortality rate of 35-45%. It is being increasingly demonstrated that the improvement of outcomes requires a tailored, individualized approach to therapy, guided by a detailed understanding of each patient's pathophysiology. In patients with ARDS, disturbances in the physiological matching of alveolar ventilation (V) and pulmonary perfusion (Q) (V/Q mismatch) are a hallmark derangement. The perfusion of collapsed or consolidated lung units gives rise to intrapulmonary shunting and arterial hypoxemia, whereas the ventilation of non-perfused lung zones increases physiological dead-space, which potentially necessitates increased ventilation to avoid hypercapnia. Beyond its impact on gas exchange, V/Q mismatch is a predictor of adverse outcomes in patients with ARDS; more recently, its role in ventilation-induced lung injury and worsening lung edema has been described. Innovations in bedside imaging technologies such as electrical impedance tomography readily allow clinicians to determine the regional distributions of V and Q, as well as the adequacy of their matching, providing new insights into the phenotyping, prognostication, and clinical management of patients with ARDS. The purpose of this review is to discuss the pathophysiology, identification, consequences, and treatment of V/Q mismatch in the setting of ARDS, employing experimental data from clinical and preclinical studies as support.

Deep feature-domain matching for cardiac-related component separation from a chest electrical impedance tomography image series: proof-of-concept study

Objectives. The cardiac-related component in chest electrical impedance tomography (EIT) measurement is of potential value to pulmonary perfusion monitoring and cardiac function measurement. In a spontaneous breathing case, cardiac-related signals experience serious interference from ventilation-related signals. Traditional cardiac-related signal-separation methods are usually based on certain features of signals. To further improve the separation accuracy, more comprehensive features of the signals should be exploited. Approach. We propose an unsupervised deep-learning method called deep feature-domain matching (DFDM), which exploits the feature-domain similarity of the desired signals and the breath-holding signals. This method is characterized by two sub-steps. In the first step, a novel Siamese network is designed and trained to learn common features of breath-holding signals; in the second step, the Siamese network is used as a feature-matching constraint between the separated signals and the breath-holding signals. Main results. The method is first tested using synthetic data, and the results show satisfactory separation accuracy. The method is then tested using the data of three patients with pulmonary embolism, and the consistency between the separated images and the radionuclide perfusion scanning images is checked qualitatively. Significance. The method uses a lightweight convolutional neural network for fast network training and inference. It is a potential method for dynamic cardiac-related signal separation in clinical settings.

Quantitative analysis of pulmonary perfusion with dual-energy CT angiography: comparison of two quantification methods in patients with pulmonary embolism.

The study aimed to evaluate a quantification method of pulmonary perfusion with Dual-Energy CT Angiography (DE-CTA) normalized by lung density in the prediction of outcome in acute pulmonary embolism (PE). In this prospective study with CTA scans acquired with different breathing protocols, two perfusion parameters were calculated: %PBV (relative value of PBV, expressed per unit volume) and PBVm (PBV normalized by lung density, expressed per unit mass). DE-CTA parameters were correlated with simplified pulmonary embolism severity index (sPESI) and with outcome groups, alone and in combinationwith tomographic right-to-left ventricular ratios (RV/LV). PBVm showed significant correlation with sPESI. PBVm presented higher accuracy than %PBV In the prediction of ICU admission or death in patients with PE, with the best performance when combined with RV/LV volumetric ratio.

Ground-glass opacity in a patient with right aortic arch and no left pulmonary artery

BackgroundHere we report a case of patients with mixed ground glass opacity in the left lung combined with congenital right aortic arch, which is only present in 0.01–0.1% of adults.Case presentationA 60-year-old woman was referred to our department with a mixed ground-glass opacity (GGO) in the upper lobe of her left lung. She had congenital right aortic arch, and the left pulmonary artery was absent. Enhanced chest computed tomography, pulmonary perfusion imaging, and three-dimensional reconstruction were performed to confirm the blood supply in the left lung and the exact location of the GGO. Because of the unusual left pulmonary vascular structure, wedge resection was performed to prevent massive hemorrhage. The final pathological examination revealed that the mixed GGO was a well-differentiated pulmonary adenocarcinoma.ConclusionThe surgical options should be evaluated carefully in view of the complications and the prognosis of the patient, when ground glass opacity is combined with congenital cardiovascular anomalies.

Selection of the End-Expiratory Pressure for Mechanical Respiratory Support (Review)

End-expiratory pressure remains one of the few parameters of mechanical respiratory support whose values have not been strictly regulated using the evidence-based approach. The absence of «gold standard» for end-expiratory pressure optimization together with its obvious significant contribution to the efficiency and safety of respiratory support has driven the search for the optimal method of choosing its values for several decades.Aim of the review: to identify the optimal methods for determining the values of end-expiratory pressure based on the analysis of its positive and negative effects in the used strategies of mechanical respiratory support.Material and methods. We analyzed 165 papers from the PubMed, Scopus, and RSCI databases of medical and biological publications. Among them we selected 86 sources that most completely covered the following subjects: respiratory support, end-expiratory pressure, recruitment, ventilation-perfusion relationships, metabolography, and gas analysis.Results. We outlined the main positive and negative effects of the end-expiratory pressure with regard to both lung biomechanical characteristics and pulmonary perfusion. The evolution of views on the methods of determining optimal values of the end-expiratory pressure was reviewed with the emphasis on a certain «fixation» of the scientific community in recent decades concerning the opening of the alveoli. The promising techniques based on the analysis of the diffusion capacity of the lungs were presented.Conclusion. Focusing on mechanical lung opening prevents the scientific community from advancing in the optimization of the end-expiratory pressure. Dynamic assessment of pulmonary diffusion efficiency provides a new perspective on the issue, offering additional ways to the development of «gold standard».

Valoración del tromboembolismo pulmonar relacionado con infección SARS-CoV-2 activa en pacientes embarazadas

AimTo analyze the sample of pregnant patients who underwent pulmonary perfusion scintigraphy to rule out the pulmonary embolism (PE) suspicion during the acute COVID-19 infection hospitalization period in our hospital. Material and methodsSPECT scintigraphy with a reduced dose (111MBq) of 99mTc-macroaggregated albumin was performed in all of the patients (n=5). The obtained images were interpreted by comparing the findings with the radiological images according to the PISAPED criteria. ResultsOnly one of the 5 patients was diagnosed with PE. Two patients obtained pathological findings of the scintigraphy attributable to radiological alterations due to COVID-19 pneumonia, and the other 2 had normal pulmonary perfussion. ConclusionGiven the non-specific features of the clinical manifestations and D-dimer values in COVID-19, as well as their similarity to those of PE, the pulmonary perfusion scintigraphy plays a crucial role in the screening of PE in these patients due to its high sensitivity and lower irradiation compared to CT. Despite the limited number of patients, the results obtained have special relevance related to the absence of scientific publications on this group of patients within the context of COVID-19 pandemic exceptional situation.

Utility of arterial to end-tidal carbon dioxide difference [P(a – ET)CO2] as a weaning index

Introduction: Quantification of physiological dead space (VDphys) provides important insight into the efficiency of ventilation and its relation to pulmonary perfusion. Arterial to end-tidal carbon dioxide difference [P(a-ET)CO2] may provide a valuable surrogate measure of VDphys and may be useful as an index of weaning success. Aim: To evaluate the utility of [P(a-ET)CO2] as a weaning index. Methods: This prospective study enrolled 52 invasively mechanically ventilated adult patients treated in Medical Intensive Care Unit (MICU) between December 2010 and December 2011. The end-tidal carbon dioxide concentration was measured using a side stream capnograph at each attempt at decreasing ventilatory support and when they were ready to be weaned. A receiver operating characteristic (ROC) curve was constructed for weaning success, progressive weaning and extubation success. A cut-off point was obtained from these curves from which the sensitivity, specificity, positive and negative predictive values were obtained. Results: The ability of [P(a-ET)CO2] as a predictor of progressive reduction in ventilator support (n = 118), predictor of weaning from mechanical ventilation (n = 40) and for extubation success (n = 39) was evaluated. The area under the curve (AUC) for progressive weaning, spontaneous breathing trial and extubation success were 0.852, 0.905 and 0.702 and a threshold of 10.5 mm Hg, 9.4 mm Hg and 9.5 mm Hg respectively were obtained. Conclusion: P(a-ET)CO2 of ≤ 10 mm Hg may be used as an index of weaning during progressive weaning from mechanical ventilation, spontaneous breathing trial and to predict success of extubation.

Prioritizing direct heart procurement in organ donors after circulatory death does not jeopardize lung transplant outcomes.

Controlled donation after circulatory death (cDCD) has become a standard in liver, kidney, and lung transplantation (LTx). Based on recent innovations in exvivo heart preservation, heart transplant centers have started to accept cDCD heart allografts. Because the heart has very limited tolerance to warm ischemia, changes to the cDCD organ procurement procedures are needed. These changes entail delayed ventilation and prolonged warm ischemia for the lungs. Whether this negatively impacts lung allograft function is unclear. A retrospective analysis of cDCD lungs transplanted between 2012 and February 2022 at the Medical University of Vienna was performed. The heart+lung group consisted of cases in which the heart was procured by a cardiac team for subsequent normothermic exvivo perfusion. A control group (lung group) was formed by cases where only the lungs were explanted. In heart+lung group cases, the heart procurement team placed cannulas after circulatory death and a hands-off time, collected donor blood for exvivo perfusion, and performed rapid organ perfusion with Custodiol solution, after which the heart was explanted. Up to this point, the lung procurement team did not interfere. No concurrent lung ventilation or pulmonary artery perfusion was performed. After the cardiac procurement team left the table, ventilation was initiated, and lung perfusion was performed directly through both stumps of the pulmonary arteries using 2 large-bore Foley catheters. This study analyzed procedural explant times, postoperative outcomes, primary graft dysfunction (PGD), duration of mechanical ventilation, length of intensive care unit (ICU) stay, and early survival after LTx. A total of 56 cDCD lungs were transplanted during the study period. In 7 cases (12.5%), the heart was also procured (heart+lung group); in 49 cases (87.5%), only the lungs were explanted (lung group). Basic donor parameters were comparable in the 2 groups. The median times from circulatory arrest to lung perfusion (24minutes vs 13.5minutes; P=.002) and from skin incision to lung perfusion (14minutes vs 5minutes; P=.005) were significantly longer for the heart+lung procedures. However, this did not affect post-transplantation PGD grade at 0hours (P=.851), 24hours (P=.856), 48hours (P=.929), and 72hours (P=.874). At 72hours after transplantation, none of the lungs in the heart+lung group but 1 lung (2.2%) in lung group was in PGD 3. The median duration of mechanical ventilation (50hours vs 41hours; P=.801), length of ICU stay (8days vs 6days; P=.951), and total length of hospital stay (27days vs 25days; P=.814) were also comparable in the 2 groups. In-hospital mortality occurred in only 1 patient of the lung group (2.2%). Although prioritized cDCD heart explantation is associated with delayed ventilation and significantly longer warm ischemic time to the lungs, post-LTx outcomes within the first year are unchanged. Prioritizing heart perfusion and explantation in the setting of cDCD procurement can be considered acceptable.

Perfusion imaging heterogeneity during NO inhalation distinguishes pulmonary arterial hypertension (PAH) from healthy subjects and has potential as an imaging biomarker

BackgroundWithout aggressive treatment, pulmonary arterial hypertension (PAH) has a 5-year mortality of approximately 40%. A patient’s response to vasodilators at diagnosis impacts the therapeutic options and prognosis. We hypothesized that analyzing perfusion images acquired before and during vasodilation could identify characteristic differences between PAH and control subjects.MethodsWe studied 5 controls and 4 subjects with PAH using HRCT and 13NN PET imaging of pulmonary perfusion and ventilation. The total spatial heterogeneity of perfusion (CV2Qtotal) and its components in the vertical (CV2Qvgrad) and cranio-caudal (CV2Qzgrad) directions, and the residual heterogeneity (CV2Qr), were assessed at baseline and while breathing oxygen and nitric oxide (O2 + iNO). The length scale spectrum of CV2Qr was determined from 10 to 110 mm, and the response of regional perfusion to O2 + iNO was calculated as the mean of absolute differences. Vertical gradients in perfusion (Qvgrad) were derived from perfusion images, and ventilation-perfusion distributions from images of 13NN washout kinetics.ResultsO2 + iNO significantly enhanced perfusion distribution differences between PAH and controls, allowing differentiation of PAH subjects from controls. During O2 + iNO, CV2Qvgrad was significantly higher in controls than in PAH (0.08 (0.055–0.10) vs. 6.7 × 10–3 (2 × 10–4–0.02), p < 0.001) with a considerable gap between groups. Qvgrad and CV2Qtotal showed smaller differences: − 7.3 vs. − 2.5, p = 0.002, and 0.12 vs. 0.06, p = 0.01. CV2Qvgrad had the largest effect size among the primary parameters during O2 + iNO. CV2Qr, and its length scale spectrum were similar in PAH and controls. Ventilation-perfusion distributions showed a trend towards a difference between PAH and controls at baseline, but it was not statistically significant.ConclusionsPerfusion imaging during O2 + iNO showed a significant difference in the heterogeneity associated with the vertical gradient in perfusion, distinguishing in this small cohort study PAH subjects from controls.

Abstract 12208: Acute Nitroglycerin Use Worsens Ventilatory Efficiency in Patients With Heart Failure With Preserved Ejection Fraction

Introduction: The marked rise in left ventricular (LV) filling pressure (ie., pulmonary capillary wedge pressure [PCWP]) during exercise and its association with adverse prognosis in patients with heart failure with preserved ejection fraction (HFpEF) has stimulated interest in therapies to decrease LV filling pressures. Although reducing LV filling pressure may improve exercise hemodynamics, this may also reduce pulmonary perfusion (Qc) and increase ventilation-perfusion (V/Q) mismatch, manifesting as an increase in ventilatory inefficiency during exercise (ie., slope of the ventilation [V̇ E ] and carbon dioxide elimination [V̇CO 2 ] relationship), which is a strong prognostic indicator of adverse outcomes in heart failure. Hypothesis: Reducing PCWP via acute nitroglycerin (NTG) treatment would increase the V̇ E /V̇CO 2 slope when compared with a placebo treatment in patients with HFpEF. Methods: 26 subjects were evaluated (age: 69±5y; BMI: 39.5±7.1kg/m 2 ; V̇O 2peak : 1.39±0.46L/min; 16 women/10 men). All subjects performed a six-minute constant-load cycling test at 20W with placebo or NTG treatment. PCWP was measured via a right-heart catheter, arterial blood gases were measured via a radial artery catheter, Qc was measured via direct Fick, and pulmonary gas exchange was measured via a customized breath-by-breath metabolic system. The V̇ E /V̇CO 2 slope was calculated as the relation between the rest-to-20W change in V̇ E and the rest-to-20W change in V̇CO 2 . Results: PCWP decreased with NTG at 20W (placebo: 20.8±5.8 vs. NTG: 16.4±5.1 mmHg, p=0.001). Qc also decreased with NTG at 20W (placebo: 8.69±1.84 vs. NTG: 8.26±1.87 L/min, p=0.01). In contrast, the V̇ E /V̇CO 2 slope increased with NTG (placebo: 37.5±5.8 vs. NTG: 39.6±7.0, p=0.01). Conclusions: These findings suggest that reducing LV filling pressure increases ventilatory inefficiency, possibly due to an increase in V/Q mismatch caused by a reduction in pulmonary perfusion. Since therapies to decrease LV filling pressure have gained considerable interest to improve exercise hemodynamics in HFpEF, further investigation is required to determine the clinical consequences of ventilation-perfusion mismatch and ventilatory inefficiency caused by a reduction in PCWP in these patients.

Roles of electrical impedance tomography in lung transplantation.

Lung transplantation is the preferred treatment method for patients with end-stage pulmonary disease. However, several factors hinder the progress of lung transplantation, including donor shortages, candidate selection, and various postoperative complications. Electrical impedance tomography (EIT) is a functional imaging tool that can be used to evaluate pulmonary ventilation and perfusion at the bedside. Among patients after lung transplantation, monitoring the graft's pulmonary function is one of the most concerning issues. The feasible application of EIT in lung transplantation has been reported over the past few years, and this technique has gained increasing interest from multidisciplinary researchers. Nevertheless, physicians still lack knowledge concerning the potential applications of EIT in lung transplantation. We present an updated review of EIT in lung transplantation donors and recipients over the past few years, and discuss the potential use of ventilation- and perfusion-monitoring-based EIT in lung transplantation.

Separation of Heart and Lung-related Signals in Electrical Impedance Tomography Using Empirical Mode Decomposition.

Electrical impedance tomography (EIT) can be used for continuous monitoring of pulmonary ventilation. However, no proper method has been developed for the separation of pulmonary ventilation and perfusion signals and the measurement of the associated ventilation/ perfusion (V/Q) ratio. Previously, various methods have been used to extract these components; however, these have not been able to effectively separate and validate cardiac- and pulmonary- related images. This study aims at validating and developing a novel method to separate cardiac- and pulmonary- related components based on the EIT simulation field of view and to simultaneously reconstruct the individual images instantly. Our approach combines the advantages of the principal component analysis (PCA) and processes that originally measure EIT data instead of handling a series of EIT images, thus introducing the empirical mode decomposition (EMD). The PCA template functions for cardiacrelated imaging and intrinsic mode functions (IMFs) of EMD for lung-related imaging are then adapted to input signals. The proposed method enables the separation of cardiac- and lung-related components by adjusting the proportion of the key components related to lung imaging, which are the fourth component (PC4) and the first component (IMF1) in PCA- and EMD-based methods, respectively. The preliminary results on the application of the method to real human EIT data revealed the consistently better performance and optimal computation compared with previous methods. This study proposes a novel method for applying EIT to evaluate the best time of V/Q matching on the cardiovascular and respiratory systems; this aspect can be investigated in future research.

Unsupervised clustering algorithms improve the reproducibility of dynamic contrast-enhanced magnetic resonance imaging pulmonary perfusion quantification in muco-obstructive lung diseases.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) allows the assessment of pulmonary perfusion, which may play a key role in the development of muco-obstructive lung disease. One problem with quantifying pulmonary perfusion is the high variability of metrics. Quantifying the extent of abnormalities using unsupervised clustering algorithms in residue function maps leads to intrinsic normalization and could reduce variability. We investigated the reproducibility of perfusion defects in percent (QDP) in clinically stable patients with cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). 15 CF (29.3 ± 9.3y, FEV1%predicted = 66.6 ± 15.8%) and 20 COPD (66.5 ± 8.9y, FEV1%predicted = 42.0 ± 13.3%) patients underwent DCE-MRI twice 1 month apart. QDP, pulmonary blood flow (PBF), and pulmonary blood volume (PBV) were computed from residue function maps using an in-house quantification pipeline. A previously validated MRI perfusion score was visually assessed by an expert reader. Overall, mean QDP, PBF, and PBV did not change within 1 month, except for QDP in COPD (p < 0.05). We observed smaller limits of agreement (± 1.96 SD) related to the median for QDP (CF: ± 38%, COPD: ± 37%) compared to PBF (CF: ± 89%, COPD: ± 55%) and PBV (CF: ± 55%, COPD: ± 51%). QDP correlated moderately with the MRI perfusion score in CF (r = 0.46, p < 0.05) and COPD (r = 0.66, p < 0.001). PBF and PBV correlated poorly with the MRI perfusion score in CF (r =-0.29, p = 0.132 and r =-0.35, p = 0.067, respectively) and moderately in COPD (r =-0.57 and r =-0.57, p < 0.001, respectively). In patients with muco-obstructive lung diseases, QDP was more robust and showed a higher correlation with the MRI perfusion score compared to the traditionally used perfusion metrics PBF and PBV.

Radionuclide methods in assessing pulmonary perfusion and ventilation in patients with connective tissue dysplasia

Aim. To perform a scintigraphic assessment of the bronchopulmonary system and pulmonary microcirculation in patients with connective tissue dysplasia.Materials and methods. The study included 31 male patients of conscription age with connective tissue dysplasia (CTD), diagnosed according to the 2019 clinical guidelines (average age (19.6 ± 2.6 years)), and 25 practically healthy individuals comparable in gender and age, who formed a control group. All patients underwent planar pulmonary ventilation – perfusion scintigraphy with determination of pulmonary alveolar – capillary permeability.Results. In patients with CTD, the apical to basal perfusion gradient (U/LQ) was on average 24% lower than in the control group (p = 0.046), and alveolar – capillary permeability was higher in both lungs, both at minute 10 and at minute 30.Conclusion. Static pulmonary ventilation – perfusion scintigraphy allows to identify functional disorders in patients with CTD at the preclinical stage: a decrease in the perfusion gradient on average by 24% compared with the control group and an increase in alveolar – capillary membrane permeability.

Favourable Short- to Mid-Term Outcome after PDA-Stenting in Duct-Dependent Pulmonary Circulation.

Background. Stenting of patent ductus arteriosus (PDA) is a minimally invasive catheter-based temporary palliative procedure that is an alternative to a surgical shunt in neonates with duct-dependent pulmonary perfusion. Methods. An observational, single-centre, cross-sectional study of patients with duct-dependent pulmonary perfusion undergoing PDA-stenting as a stage I procedure and an analysis of short- to mid-term follow-up until a subsequent surgical procedure (stage II), with a focus on the interstage course. Results. Twenty-six patients were treated with PDA-stenting at a median (IQR) age of 7 (4–10) days; 10/26 patients (38.5%) (6/10 single pulmonary perfusion) were intended for later univentricular palliation, 16/26 patients (61.5%) (13/16 single pulmonary perfusion) for biventricular repair. PDA diameter was 2.7 (1.8–3.2) mm, stent diameter 3.5 (3.5–4.0) mm. Immediate procedural success was 88.5%. The procedure was aborted, switching to immediate surgery after stent embolisation, malposition or pulmonary coarctation in three patients (each n = 1). During mid-term follow-up, one patient needed an additional surgical shunt due to severe cyanosis, while five patients underwent successful catheter re-intervention 27 (17–30) days after PDA-stenting due to pulmonary hypo- (n = 4) or hyperperfusion (n = 1). Interstage mortality was 8.6% (2/23), both in-hospital and non-procedure-related. LPA grew significantly (p = 0.06) between PDA-stenting and last follow-up prior to subsequent surgical procedure (p = 0.06). RPA Z-scores remained similar (p = 0.22). The subsequent surgical procedure was performed at a median age of 106 (76.5–125) days. Conclusions. PDA-stenting is a feasible, safe treatment option, with the need for interdisciplinary decision-making beforehand and surgical backup afterwards. It allows adequate body and pulmonary vessel growth for subsequent surgical procedures. Factors determining the individual patient’s course should be identified in larger prospective studies.