Pulmonary arterial enlargement in patients with acute exacerbation of interstitial pneumonia

Unmasking a Silent Threat: Improving Pulmonary Hypertension Screening Methods for Interstitial Lung Disease Patients

This article provides a comprehensive overview of the latest literature on the diagnostics and treatment of pulmonary hypertension (PH) associated with interstitial lung disease (ILD). Heightened suspicion for PH arises when the advancement of dyspnoea in ILD patients diverges from the expected pattern of decline in pulmonary function parameters. The complexity of PH associated with ILD (PH-ILD) diagnostics is emphasized by the limitations of transthoracic echocardiography in the ILD population, necessitating the exploration of alternative diagnostic approaches. Cardiac magnetic resonance imaging (MRI) emerges as a promising tool, offering insights into hemodynamic parameters and providing valuable prognostic information. The potential of biomarkers, alongside pulmonary function and cardiopulmonary exercise tests, is explored for enhanced diagnostic and prognostic precision. While specific treatments for PH-ILD remain limited, recent studies on inhaled treprostinil provide new hope for improved patient outcomes.

Prognostic utility of pulmonary artery and ascending aorta diameters derived from computed tomography in COVID-19 patients

Aim

Chest computed tomography (CT) imaging plays a diagnostic and prognostic role in Coronavirus disease 2019 (COVID‐19) patients. This study aimed to investigate and compare predictive capacity of main pulmonary artery diameter (MPA), ascending aorta diameter (AAo), and MPA‐to‐AAo ratio to determine in‐hospital mortality in COVID‐19 patients.

Materials and methods

This retrospective study included 255 hospitalized severe or critical COVID‐19 patients. MPA was measured at the level of pulmonary artery bifurcation perpendicular to the direction of the vessel through transverse axial images and AAo was measured by using the same CT slice at its maximal diameter. MPA‐to‐AAo ratio was calculated by division of MPA to AAo.

Results

Multivariate logistic regression model yielded MPA ≥29.15 mm (OR: 4.95, 95% CI: 2.01–12.2, p = 0.001), MPA (OR: 1.28, 95% CI: 1.13–1.46, p < 0.001), AAo (OR: .90, 95% CI: .81–.99, p = 0.040), and MPA‐to‐AAo ratio ≥.82 (OR: 4.67, 95% CI: 1.86–11.7, p = 0.001) as independent predictors of in‐hospital mortality. Time‐dependent multivariate Cox‐proportion regression model demonstrated MPA ≥29.15 mm (HR: 1.96, 95% CI: 1.03–3.90, p = 0.047) and MPA (HR: 1.08, 95% CI: 1.01–1.17, p = 0.048) as independent predictors of in‐hospital mortality, whereas AAo and MPA‐to‐AAo ratio did not reach statistical significance.

Conclusion

Pulmonary artery enlargement strongly predicts in‐hospital mortality in hospitalized COVID‐19 patients. MPA, which can be calculated easily from chest CT imaging, can be beneficial in the prognostication of these patients.

Machine Learning to Predict In-Hospital Mortality in COVID-19 Patients Using Computed Tomography-Derived Pulmonary and Vascular Features

Pulmonary parenchymal and vascular damage are frequently reported in COVID-19 patients and can be assessed with unenhanced chest computed tomography (CT), widely used as a triaging exam. Integrating clinical data, chest CT features, and CT-derived vascular metrics, we aimed to build a predictive model of in-hospital mortality using univariate analysis (Mann-Whitney U test) and machine learning models (support vectors machines (SVM) and multilayer perceptrons (MLP)). Patients with RT-PCR-confirmed SARS-CoV-2 infection and unenhanced chest CT performed on emergency department admission were included after retrieving their outcome (discharge or death), with an 85/15% training/test dataset split. Out of 897 patients, the 229 (26%) patients who died during hospitalization had higher median pulmonary artery diameter (29.0 mm) than patients who survived (27.0 mm, p < 0.001) and higher median ascending aortic diameter (36.6 mm versus 34.0 mm, p < 0.001). SVM and MLP best models considered the same ten input features, yielding a 0.747 (precision 0.522, recall 0.800) and 0.844 (precision 0.680, recall 0.567) area under the curve, respectively. In this model integrating clinical and radiological data, pulmonary artery diameter was the third most important predictor after age and parenchymal involvement extent, contributing to reliable in-hospital mortality prediction, highlighting the value of vascular metrics in improving patient stratification.

Computed tomography appearances of the lung parenchyma in pulmonary hypertension

Computed tomography (CT) is a valuable tool in the workup of patients under investigation for pulmonary hypertension (PH) and may be the first test to suggest the diagnosis. CT parenchymal lung changes can help to differentiate the aetiology of PH. CT can demonstrate interstitial lung disease, emphysema associated with chronic obstructive pulmonary disease, features of left heart failure (including interstitial oedema), and changes secondary to miscellaneous conditions such as sarcoidosis. CT also demonstrates parenchymal changes secondary to chronic thromboembolic disease and venous diseases such as pulmonary venous occlusive disease (PVOD) and pulmonary capillary haemangiomatosis (PCH). It is important for the radiologist to be aware of the various manifestations of PH in the lung, to help facilitate an accurate and timely diagnosis. This pictorial review illustrates the parenchymal lung changes that can be seen in the various conditions causing PH.

CT-derived pulmonary vascular metrics and clinical outcome in COVID-19 patients

To assess pulmonary vascular metrics on chest CT of COVID-19 patients, and their correlation with pneumonia extent (PnE) and outcome, we analyzed COVID-19 patients with an available previous chest CT, excluding those performed for cardiovascular disease. From February 21 to March 21, 2020, of 672 suspected COVID-19 patients from two centers who underwent CT, 45 RT-PCR-positives (28 males, median age 75, IQR 66-81 years) with previous CTs performed a median 36 months before (IQR 12-72 months) were included. We assessed PnE, pulmonary artery (PA) diameter, ascending aorta (Ao) diameter, and PA/Ao ratio. Most common presentations were fever and dyspnea (15/45) and fever alone (13/45). Outcome was available for 41/45 patients, 15/41 dead and 26/41 discharged. Ground-glass opacities (GGOs) alone were found in 29/45 patients, GGOs with consolidations in 15/45, consolidations alone in 1/45. All but one patient had bilateral pneumonia, 9/45 minimal, 22/45 mild, 9/45 moderate, and 5/45 severe PnE. PA diameter (median 31 mm, IQR 28-33 mm) was larger than before (26 mm, IQR 25-29 mm) (P<0.001), PA/Ao ratio (median 0.83, IQR 0.76-0.92) was higher than before (0.76, IQR 0.72-0.82) (P<0.001). Patients with adverse outcome (death) had higher PA diameter (P=0.001), compared to discharged ones. Only weak correlations were found between ΔPA or ΔPA/Ao and PnE (ρ≤0.453, P≤0.032), with 4/45 cases with moderate-severe PnE and minimal increase in PA metrics. In conclusion, enlarged PA diameter was associated to death in COVID-19 patients, a finding deserving further investigation as a potential driver of therapy decision-making.

Cardiovascular Computed Tomography Findings after Pneumonectomy: Comparison to Lobectomy

RATIONALE AND OBJECTIVES

To identify and compare cardiovascular findings on computed tomography (CT) scans after pneumonectomy (PNX) with those after lobectomy (LOBX).

MATERIALS AND METHODS

Pre- and postoperative CT scans from 25 PNX patients were retrospectively analyzed and compared to those from 30 LOBX patients. The diameter of the main pulmonary artery (PA) and its ratio to the ascending aorta (PA/Ao) were determined. Cardiac morphometry values were ascertained by measuring maximum diameters of the right and left ventricle on axial (RV_axial, LV_axial) and four-chamber (RV_4-ch, LV_4-ch) views. RV_axial/LV_axial and RV_4-ch/LV_4-ch ratios were calculated. Vessel stumps were evaluated for thrombosis.

RESULTS

After PNX, PA (31.1 ± 5.8 mm vs 28.7 ± 5.4 mm, P = 0.003), PA/Ao (0.97 ± 0.15 vs 0.86 ± 0.12, P = 0.0001), and cardiac morphometry values significantly increased (RV_axial 43.6 ± 7.4 vs 39.4 ± 7.1, P = 0.029; RV_4-ch 41.1 ± 6.3 vs 37.6 ± 5.7, P = 0.041; RV_axial/LV_axial 1.18 ± 0.27 vs 1.03 ± 0.22, P = 0.04; RV_4-ch/LV_4-ch 1.17 ± 0.21 vs 1.02 ± 0.16, P = 0.03). There were no significant differences between right and left PNX. One case of PA stump thrombosis was identified after right PNX. LOBX resulted in a significant increase in PA (30.6 ± 4.3 vs 28.7 ± 3.5, P = 0.005) and PA/Ao (0.90 ± 0.09 vs 0.85 ± 0.10, P = 0.017), whereas cardiac morphometry values were not significantly changed compared to baseline values. No vessel stump thrombosis was observed after LOBX. In comparison to LOBX, all ascertained values were significantly elevated after PNX.

CONCLUSIONS

Morphologic alterations of the cardiovascular system following PNX can be identified on CT scans. Alterations are more distinct after PNX compared to LOBX.

COMPUTED TOMOGRAPHIC MEASUREMENT OF THE MAIN PULMONARY ARTERY TO AORTIC DIAMETER RATIO IN HEALTHY DOGS: A COMPARISON TO ECHOCARDIOGRAPHICALLY DERIVED RATIOS

Indicators of pulmonary hypertension in dogs examined with thoracic computed tomography (CT) are not well established in the veterinary literature. In humans, the main pulmonary artery to aortic diameter ratio (MPA:Ao) measured via CT, has been shown to be more sensitive than echocardiographic variables for predicting presence and severity of pulmonary hypertension, in some cases. In veterinary literature, the MPA:Ao has been determined echocardiographically to have an upper limit of about 1:1. Measurement of this ratio has not been described in dogs using CT. The objectives of this cross-sectional, prospective study were to compare echocardiographic measurement of MPA:Ao with that obtained via CT, determine if measurement of MPA:Ao via CT is repeatable and reproducible, and determine the effect of respiration and contrast administration on the measurement of MPA:Ao via CT. Ten healthy dogs without pulmonary hypertension were anesthetized to undergo thoracic CT using three protocols and echocardiography. The MPA:Ao was measured three times by three observers for each of the three CT protocols and compared to echocardiographic measurements. The mean MPA:Ao measured among all observers and CT protocols was 1.108 ± 0.152 (SD). The effect of CT scan protocol on MPA:Ao significantly differed among the three methods (P = 0.0014), where expiratory scans had lower MPA:Ao than inspiratory scans. The ratio measured on inspiratory CT scans consistently overestimated MPA:Ao when compared to echocardiography (bias = 0.226). Findings did not support the echocardiographically derived upper limit of MPA:Ao as an upper limit for determination of main pulmonary arterial enlargement on CT.

Comparison of CT-Determined Pulmonary Artery Diameter, Aortic Diameter, and Their Ratio in Healthy and Diverse Clinical Conditions

BACKGROUND

The main pulmonary artery diameter (mPA), aortic diameter (Ao), and the mPA/Ao ratio, easily measured using chest computed tomography (CT), provide information that enables the diagnosis and evaluation of cardiopulmonary diseases. Here, we used CT to determine the sex- and age-specific distribution of normal reference values for mPA, Ao, and mPA/Ao ratio in an adult Korean population.

METHODS

Data from non-contrast, ECG-gated, coronary-calcium-scoring CT images of 2,547 individuals who visited the Health Screening Center of the Severance Hospital were analyzed. Healthy individuals (n = 813) included those who do not have hypertension, diabetes, asthma, obstructive lung disease, ischemic heart disease, stroke, smoking, obesity, and abnormal CT findings. Both mPA and Ao were measured at the level of bifurcation of the main pulmonary artery.

RESULTS

The mean mPA and Ao were 25.9 mm and 30.0 mm in healthy participants, respectively, while the mean mPA/Ao ratio was 0.87. Medical conditions associated with a larger mPA were male, obesity, smoking history, hypertension, and diabetes. A larger mPA/Ao ratio was associated with female, the obese, non-smoker, normotensive, and normal serum level of lipids, while a smaller mPA/Ao ratio was associated with older age. In healthy individuals, the 90th percentile sex-specific mPA, Ao, and mPA/Ao ratio were, 31.3 mm (95% CI 29.9-32.2), 36.8 mm (95% CI 35.7-37.5), and 1.05 (95% CI 0.99-1.07) in males, and 29.6 mm (95% CI 29.1-30.2), 34.5 mm (95% CI 34.1-34.9), and 1.03 (95% CI 1.02-1.06) in females, respectively.

CONCLUSION

In the Korean population, the mean mPA reference values in male and female were 26.5 mm and 25.8 mm, respectively, while the mean mPA/Ao ratio was 0.87. These values were influenced by a variety of underlying medical conditions.