Contrast reflux into the inferior vena cava on computer tomographic pulmonary angiography is a predictor of 24-hour and 30-day mortality in patients with acute pulmonary embolism

Epicardial adipose tissue as a prognostic marker in acute pulmonary embolism

BACKGROUND

Epicardial adipose tissue (EAT) has been established as a quantitative imaging biomarker associated with disease severity in coronary heart disease. Our aim was to use this prognostic marker derived from computed tomography pulmonary angiography (CTPA) for the prediction of mortality and prognosis in patients with acute pulmonary embolism.

METHODS

The clinical database was retrospectively screened for patients with acute pulmonary embolism between 2015 and 2021. Overall, 513 patients (216 female, 42.1%) were included in the analysis. The study end-point was 30-day mortality. Epicardial adipose tissue was measured on the diagnostic CTPA in a semiquantitative manner. The volume and density of EAT were measured for every patient.

RESULTS

Overall, 60 patients (10.4%) died within the 30-day observation period. The mean EAT volume was 128.3 ± 65.0 cm3 in survivors and 154.6 ± 84.5 cm3 in nonsurvivors (p = 0.02). The density of EAT was -79.4 ± 8.3 HU in survivors and -76.0 ± 8.4 HU in nonsurvivors (p = 0.86), and EAT density was associated with 30-day mortality (odds ratio [OR] = 1.07; 95% confidence interval [CI]: 1.03; 1.1, p < 0.001) but did not remain statistically significant in multivariable analysis. No association was identified between EAT volume and 30-day mortality (OR = 1.0; 95% CI: 1.0; 1.0, p = 0.48).

CONCLUSION

There might be an association between EAT density and mortality in patients with acute pulmonary embolism. Further studies are needed to elucidate the prognostic relevance of EAT parameters in patients with acute pulmonary embolism.

Early discharge and home treatment of patients with acute pulmonary embolism in the tertiary care setting

Acute pulmonary embolism (PE) is a potentially life-threatening disease. Current guidelines suggest risk-adapted management. Hospitalization is required for intermediate- and high-risk patients. Early discharge and home treatment are considered safe in the majority of low-risk patients. In this study, we describe characteristics, discharge, and outcome of outpatients diagnosed with acute PE at a tertiary care center. All outpatients undergoing computed tomography pulmonary angiography or ventilation/perfusion lung scan between 01.01.2016 and 31.12.2019 at the University Hospital Vienna, Austria, were screened for a PE diagnosis. Electronic patient charts were used to extract characteristics, clinical course, and outcomes. Within the 4-year period, 709 outpatients (median age: 62 years, 50% women) were diagnosed with PE. Thirty-three (5%) patients were classified as high-risk, 159 (22%) as intermediate-high, 332 (47%) as intermediate-low, and 185 (26%) as low-risk PE according to the European Society of Cardiology risk stratification. In total, 156 (22%) patients (47% with low-risk and 20% with intermediate-low-risk PE) were discharged as outpatients and received home treatment. Rates for home treatment increased 2.4-fold during the study period. Thirty-day mortality in the entire population was 4.9%. All low-risk patients and all but one patient with home treatment survived the first 30 days. Home treatment significantly increased over time and seems to be safe in routine clinical practice. Notably, one in five intermediate-low-risk patients was discharged immediately, suggesting that a subpopulation of intermediate-low-risk patients may also be eligible for home treatment.

A novel angiographic method to estimate arterial blood flow rates using contrast reflux: Effect of injection parameters

BACKGROUND

Contrast reflux, which is the retrograde movement of contrast against flow direction, is commonly observed during angiography. Despite a vast body of literature on angiography, the hemodynamic factors affecting contrast reflux have not been studied. Numerous methods have been developed to extract flow from angiography, but the reliability of these methods is not yet sufficient to be of routine clinical use.

PURPOSE

To evaluate the effect of baseline blood flow rates and injection conditions on the extent of contrast reflux. To estimate arterial flow rates based on measurement of contrast reflux length.

MATERIALS AND METHODS

Iodinated contrast was injected into an idealized tube as well as a physiologically accurate model of the cervico-cerebral vasculature. A total of 194 high-speed angiograms were acquired under varying "blood" flow rates and injection conditions (catheter size, injection rate, and injection time). The length of contrast reflux was compared to the input variables and to dimensionless fluid dynamics parameters at the catheter-tip. Arterial blood flow rates were estimated using contrast reflux length as well as a traditional transit-time method and compared to measured flow rates.

RESULTS

Contrast reflux lengths were significantly affected by contrast injection rate (p < 0.0001), baseline blood flow rate (p = 0.0004), and catheter size (p = 0.04), but not by contrast injection time (p = 0.4). Reflux lengths were found to be correlated to dimensionless fluid dynamics parameters by an exponential function (R²  = 0.6-0.99). When considering the entire dataset in unison, flow estimation errors with the reflux-length method (39% ± 33%) were significantly higher (p = 0.003) than the transit-time method (33% ± 36%). However, when subgrouped by catheter, the error with the reflux-length method was substantially reduced and was significantly lower (14% ± 14%, p < 0.0001) than the transit-time method.

CONCLUSION

Results show correlations between contrast reflux length and baseline hemodynamic parameters that have not been reported previously. Clinically relevant blood flow rate estimation is feasible by simple measurement of reflux length. In vivo and clinical studies are required to confirm these correlations and to refine the methodology of estimating blood flow by reflux.

Computed Tomography Embolus Texture Analysis as a Prognostic Marker of Acute Pulmonary Embolism

Texture analysis is a quantitative imaging analysis that provides novel biomarkers beyond conventional image reading. Our aim was to use texture analysis of pulmonary emboli derived from thoracic computed tomography for prediction of mortality and prognosis of acute pulmonary embolism (PE). Overall, 216 patients (116 female, 53.7%) were included in the analysis. Texture analysis was calculated on axial slices of the contrast enhanced pulmonary angiography of the proximal embolus. Clinical scores, serological parameters, need for intubation, intensive care unit (ICU) admission and mortality was assessed and correlated with the texture features. In the correlation analysis, there were several associations with mortality in days, the highest for the parameter S(0,5)SumVarnc (r = -0.43, P < 0.001). Another parameter, S(3,-3)AngScMom correlated with sepsis-related organ failure assessment score (SOFA)-score (r = 0.31, P < 0.001). Several texture features correlated with venous lactate and glucose levels. In discrimination analysis, there were significant differences in regard to texture features between survivors and non-survivors and between patients with and without the need for ICU admission (P = 0.02, respectively). These results highlight the potential clinical benefit of texture features in patients with acute PE as novel imaging biomarkers. Further studies are needed to validate these results.

Time efficiency and reliability of established computed tomographic obstruction scores in patients with acute pulmonary embolism

Objective

Acute pulmonary embolism (PE) is a life-threatening disease with a high mortality. Computed tomographic pulmonary angiography (CTPA) is used in clinical routine for diagnosis of PE. Many pulmonary obstruction scores were proposed to aid in stratifying clinical course of PE. The purpose of the present study was to compare common pulmonary obstruction scores in PE in regard of time efficiency and interreader agreement based upon a representative patient sample.

Methods

Overall, 50 patients with acute PE were included in this single center, retrospective analysis. Two readers scored the CT images blinded to each other and assessed the scores proposed by Mastora et al., Qanadli et al., Ghanima et al. and Kirchner et al. The required time was assessed of each reading for scoring.

Results

For reader 1, Mastora score took the longest time duration, followed by Kirchner score, Qanadli score and finally Ghanima score (every test, p<0.0001). The interreader variability was excellent for all scores with no significant differences between them. In the Spearman’s correlation analysis strong correlations were identified between the scores of Mastora, Qanadli and Kirchner, whereas Ghanima score was only moderately correlated with the other scores. There was a weak correlation between time duration and Mastora score (r = 0.35, p = 0.014). For the Ghanima score, a significant inverse correlation was found (r = -0.67, p<0.0001).

Conclusion

For the investigated obstruction scores, there are significant differences in regard of time consumption with no relevant differences in regard of interreader variability in patients with acute pulmonary embolism. Mastora score requires the most time effort, whereas the score by Ghanima the least time.