Computed tomographic pulmonary angiography in the assessment of severity of acute pulmonary embolism and right ventricular dysfunction

Alterations and Significance of Computed Tomography Pulmonary Angiography-Derived Parameters in Older Patients With Acute Pulmonary Embolism

OBJECTIVE

This study aimed to investigate changes of computed tomography pulmonary angiography (CTPA)-derived parameters in older adults with acute pulmonary embolism (APE).

METHODS

According to the pulmonary artery obstruction index (PAOI), patients with APE were divided into the A1 (PAOI ≥30%, n = 57) and A2 (PAOI <30%, n = 40) groups. Participants without APE were placed in group B (n = 170). The left atrial (LA) and left ventricular (LV) parameters among the three groups were compared, and the parameter changes in the 44 patients with APE were analyzed before and after treatment. The correlation between APE severity and the parameters was analyzed using correlation analysis.

RESULTS

The left-to-right diameters (LR) of LA, and LR × anteroposterior diameters (AP) of LA and LV: A1 < A2 < B; LR of LV: A1 < A2, B; AP of LA and LV: A1, A2 < B. After treatment, LR and LR × AP of the LA and LV were significantly increased in the group A1 and LR of the LV and LR × AP of the LA and LV were elevated in the group A2. Acute pulmonary embolism severity was closely associated with LR × AP ( r = -0.557) and LR ( r = -0.477) of LA.

CONCLUSIONS

With an increase in the degree of obstruction, older adults had a smaller LA and LV. Furthermore, the LR and LR × AP values of the LA were significantly decreased. These results contribute to in-time risk stratification.

Importance of computed tomography pulmonary angiography for predict 30-day mortality in acute pulmonary embolism patients

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The study provides a cut-off value of RV diameter and CT obstruction index by CTPA to predict acute PE patients' mortality.

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RV diameter of 53 mm or over and CT obstruction index >70 % is associated with increased 30-day mortality in APE patients.

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Increased RV diameter by CTPA is a better predictor of mortality than the clinical Pulmonary Embolism Severity Index (PESI).

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CTPA can be valuable as both the diagnostic and prognostic tool in APE patients.

Objective

The purpose of the present study was to assess the implications of different parameters of computed tomography pulmonary angiography (CTPA) to predict 30-day mortality in acute pulmonary embolism (APE) patients.

Material and Method

Patients who had clinical suspicion of APE and underwent CTPA were recruited in a retrospective cohort study. The findings of the CTPA included the parameters of right ventricular dysfunction (RVD), the severity of obstruction to the pulmonary artery by CT obstruction index, and the ratio of pulmonary trunk diameter and aorta. The endpoint of the study was established as the 30-day mortality associated with APE.

Results

A total of 238 patients with a confirmed APE diagnosis with CTPA were included in the study; 26 (10.9 %) of those patients died within 30 days. In patients with cancer and the Pulmonary Embolism Severity Index (PESI) class 5, the mortality rate was significantly higher. Compared with survivors, the mean CT obstruction index in the non-survivor group was significantly higher (p < 0.001). Higher mortality was associated with all RVD parameters identified by CTPA, such as the RV/LV ratio (p < 0.001), interventricular septum deviation grade 3 (p < 0.001), increased RV diameter (p < 0.001), and IVC contrast reflux (p < 0.001). The highest adjusted odds ratio was RV diameter at 1.094, followed by PESI and the CT obstruction index at 1.040.

Conclusion

CTPA-detected RVD parameters and CT obstruction index can predict a 30-day mortality rate in APE patients and be used for risk stratification. In APE patients, the RV diameter of 53 mm or greater and the CT obstruction index >70% is associated with increased 30-day mortality.

Decreased pulmonary artery distensibility as a marker for severity in acute pulmonary embolism patients undergoing ECG-gated CTPA

To investigate the characteristics of pulmonary artery distensibility (PAD) in patients with acute pulmonary embolism (APE) and to assess whether a relationship exists between PAD and the disease severity. Clinical and radiological data of 30 APE patients who underwent retrospective electrocardiogram (ECG)-gated computed tomography pulmonary angiography (CTPA) with a definite diagnosis of APE were retrospectively reviewed in the present study, including 15 subjects in severe (SPE) group and 15 subjects in non-severe (NSPE) group. PAD and cardiac function parameters were compared between the two groups, their relationships were investigated, and receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of the above parameters for the diagnosis of APE severity. The PAD decreased in the following order: NSPE group (6.065 ± 2.114) × 10^-3 (%/mmHg), and SPE group (4.334 ± 1.777) × 10^-3 (%/mmHg) (P < 0.05). All the cardiac function parameters except RA/LAdiameter showed statistically significant different values between the two groups (P < 0.05). As APE severity increased, the cardiac morphological measurements of RV/LVdiameter, RV/LVarea, RVEDV/LVEDV and RVESV/LVESV increased. There was a weak to moderate negative correlation between PAD and PAmax, PAmin, PA/AAmin, PA/AAmax, RV/LVdiameter, RV/LVarea (r = -0.393 to -0.625), that is, PAD was inversely correlated with cardiac function parameters. There was a moderate negative correlation between PAD and hemoptysis(r = -0.672). The area under the ROC curve (AUC) of PAD was 0.724, the critical value was 4.137 × 10^-3  mm/Hg, and the sensitivity and specificity were 60.0% and 93.3%, respectively. PAmin showed the strongest discriminatory power to identify high-risk patients (AUC = 0.827), with the highest sensitivity of 100%, which was also achieved by RA/LAarea. The PAD obtained by retrospective ECG-gated CTPA could be an indicator to be used in the evaluation of the presence and severity of APE.

CTPA pulmonary artery distensibility in assessment of severity of acute pulmonary embolism and right ventricular function

To investigate the characteristics of pulmonary artery distensibility (PAD) in patients with acute pulmonary embolism (APE) and to assess the correlation of PAD with APE severity and right ventricular function. A total of 33 patients who underwent retrospective electrocardiogram (ECG)-gated computed tomography pulmonary angiography (CTPA) with a definite diagnosis of APE were included in the study. According to APE severity, the patients were divided into severe (SPE) and non-severe (NSPE) groups. Data from a control group without APE matching the basic demographics of the APE patients were collected. Pulmonary artery distensibility (PAD) and right ventricular function parameters were compared among the 3 groups, their relationships were investigated, and receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of the above parameters for the diagnosis of APE severity. The PAD values of the control, NSPE, and SPE groups were (7.877 ± 2.637) × 10-3 mm/Hg, (6.050 ± 2.011) × 10-3 mm/Hg, (4.321 ± 1.717) × 10-3 mm/Hg, respectively (P < .01). There were statistically significant differences in right ventricular function parameters among the 3 groups (P < .05). The correlation analysis between PAD and right ventricular function parameters showed a weak negative correlation (r = -0.281--0.392). The area under the ROC curve of PAD was 0.743, the critical value was 4.200, and the sensitivity and specificity were 62.5% and 94.1%, respectively. The PAD obtained by retrospective ECG-gated CTPA could accurately evaluate APE severity and right ventricular function. As the severity of APE increases, PAD decreases, which is helpful to identify patients at high risk of APE.

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

BACKGROUND

Acute pulmonary embolism (PE) is a common disease with a high mortality. Computed tomographic pulmonary angiography (CTPA) represents the current gold standard for the evaluation of patients with suspected PE.

PURPOSE

To search possible CTPA predictors of 24-h and 30-day mortality in PE.

MATERIAL AND METHODS

Overall, 224 patients with PE (46.4% women, mean age 64.7 ± 16.7 years) were acquired. CTPA was performed on a multi-slice CT scanner. The following radiological parameters were estimated: thrombotic obstruction index; diameter of the pulmonary trunk (mm); short axis ratio of right ventricle/left ventricle; diameter of the azygos vein (mm); diameter of the superior and inferior vena cava (mm); and reflux of contrast medium into the inferior vena cava (IVC).

RESULTS

Patients who died within the first 24 h after admission (n = 32, 14.3%) showed a reflux grade 3 into IVC more often than survivors (odds ratio [OR] 7.6, 95% confidence interval [CI] 3.3-17.7; P < 0.001). Other relevant CTPA parameters were diameter of IVC (OR 1.1, 95% CI 1.01-1.21; P = 0.034) and diameter of the pulmonary trunk (OR 0.91, 95% CI 0.82-1.01, P = 0.074), whereas the Mastora score showed nearly no influence (OR 1.01, 95% CI 0.99-1.02, P = 0.406). Furthermore, 61 (27.2%) patients died within the first 30 days after admission. These patients showed a reflux grade 3 into IVC more often than survivors (OR 3.4, 95% CI 1.7-7.0; P = 0.001). Other CTPA parameters, such as diameter of IVC (OR 1.04, 95% CI 0.97-1.12; P = 0.277) and diameter of the pulmonary trunk (OR 0.96, 95% CI 0.89-1.04; P = 0.291), seem to have no relevant influence, whereas Mastora score did (OR 0.99, 95% CI 0.976-0.999, P = 0.045).

CONCLUSION

Subhepatic contrast reflux into IVC is a strong predictor of 24-h and 30-day mortality in patients with acute PE.

Correlating computed tomography pulmonary angiography signs of right ventricular strain in pulmonary embolisms to clinical outcomes

INTRODUCTION:

Right ventricular strain (RVS) in pulmonary embolism (PE) can be used to stratify risk and direct intervention. The clinical significance of computed tomography pulmonary angiogram (CTPA)-derived radiologic signs of RVS, however, remains incompletely characterized. We retrospectively analyzed a cohort of persons with acute PE to determine which, if any, findings of RVS on CTPA correlate with clinical outcomes.

METHODS:

All patients with PE diagnosed on CTPA from March 2013 through February 2015 at Lyndon B. Johnson Hospital were identified. Their records were retrospectively reviewed to identify length of stay, intensive care unit (ICU) placement, hemodynamic failure, use of thrombolytics, vasopressor requirement, mechanical ventilation, and attributable mortality. Three radiologists, blinded to clinical outcomes, separately reviewed the cohort's CTPAs to identify signs of RVS – pulmonary trunk size, internal size of the right and left ventricles, paradoxical interventricular septal bowing, inferior vena cava (IVC) contrast reflux, and hepatic vein contrast reflux.

RESULTS:

In our cohort of 102 persons, 12 demonstrated hemodynamic failure, 13 required ICU placement, 3 received thrombolysis, and 5 had death attributable to PE. The greatest interobserver agreement among radiologists existed for the presence of increased pulmonary trunk size (0.76 kappa by %agreement) and hepatic vein contrast reflux (0.92 kappa by %agreement). A multiple regression analysis found that when 100% radiologist agreement existed, presence of paradoxical intravenous septal bowing predicted thrombolytic usage (P = 0.02), and the presence of IVC reflux predicted attributable mortality (P = 0.03).

CONCLUSION:

Only IVC contrast reflux was associated with increased mortality, and no other sign of RVS on CTPA correlated with clinical outcomes. This suggests that most signs of RVS on CTPA do not reliably predict PE severity. Therefore, RVS seen by CTPA should be used cautiously in weighing the decision to initiate thrombolytics.

The assessment of acute pulmonary embolism severity using CT angiography features

Background

This study was conducted to detect the association between radiologic features of CT pulmonary angiography (CTPA) and pulmonary embolism severity index (PESI).

Methods

A total of 150 patients with a definite diagnosis of PE entered the study. The CTPA feature including obstruction index, pulmonary trunk size, presence of backwash contrast, septal morphology, right ventricular (RV) and left ventricular (LV) dimensions, and RV/LV ratio were examined. The severity of the PE was estimated using PESI. The association between CTPA indices and PESI was measured. Statistical analysis was conducted using the SPSS software. P value < 0.05 was considered as statistically significant.

Results

A positive correlation was detected between the obstruction index and PESI (r = 0.45, P < 0.05). Moreover, PESI was significantly higher in patients with a more dilated pulmonary trunk (r = 0.20, P < 0.05). The backwash contrast and abnormal septal morphology were significantly more common among patients with higher PESI (P < 0.05). However, no significant correlation was detected between RV, LV, RV/LV, and PESI. The most predictor of high-risk PE was dilated pulmonary trunk with an odds ratio of 4.4.

Conclusion

Higher Obstruction index, dilated pulmonary trunk, presence of backwash contrast, and an abnormal septal morphology can be associated with a higher PESI.

Acute pulmonary embolism: a concise review of diagnosis and management

An acute pulmonary embolism (aPE) is characterised by occlusion of one or more pulmonary arteries. Physiological disturbance may be minimal, but often cardiac output decreases as the right ventricle attempts to overcome increased afterload. Additionally, ventilation-perfusion mismatches can develop in affected vascular beds, reducing systemic oxygenation. Incidence is reported at 50-75 per 100 000 in Australia and New Zealand, with 30-day mortality rates ranging from 0.5% to over 20%. Incidence is likely to increase with the ageing population, increased survival of patients with comorbidities that are considered risk factors and improving sensitivity of imaging techniques. Use of clinical prediction scores, such as the Wells score, has assisted in clinical decision-making and decreased unnecessary radiological investigations. However, imaging (i.e. computed tomography pulmonary angiography or ventilation-perfusion scans) is still necessary for objective diagnosis. Anti-coagulation remains the foundation of PE management. Haemodynamically unstable patients require thrombolysis unless absolutely contraindicated, while stable patients with right ventricular dysfunction or ischaemia should be aggressively anti-coagulated. Stable patients with no right ventricular dysfunction can be discharged home early with anti-coagulation and review. However, treatment should be case dependent with full consideration of the patient's clinical state. Direct oral anti-coagulants have become an alternative to vitamin K antagonists and are facilitating shorter hospital admissions. Additionally, duration of anti-coagulation must be decided by considering any provoking factors, bleeding risk and comorbid state. Patients with truly unprovoked or idiopathic PE often require indefinite treatment, while in provoked cases it is typically 3 months with some patients requiring longer periods of 6-12 months.

Health risk stratification based on computed tomography pulmonary artery obstruction index for acute pulmonary embolism

Early effective identification of high-risk patients for acute pulmonary embolism (APE) contributes to timely treatment. The pulmonary artery obstruction index (PAOI) in computed tomography angiography (CTA) is a semi-quantitative observation index, commonly used to evaluate the severity of a patient's condition. This study explores the ability of PAOI to assess the risk stratification of APE. Thirty patients with APE were analysed. They were classified according to the guidelines, and the PAOI and cardiovascular parameters were measured in CTA. The difference of PAOI between different risk stratification patients was compared, and the predictive value of the PAOI for high-risk stratification was evaluated by the receiver operating characteristic curve. The correlation between PAOI and cardiovascular parameters was also analysed by Spearman correlation analysis. The PAOI in low- and high-risk patients was (33.2 ± 18.6)% and (68.1 ± 11.8)% respectively, and the difference was statistically significant. The PAOI was strongly predictive for high-risk patients. The cut-off value was 52.5%, with a sensitivity of 100% and specificity of 81.0%. The PAOI was correlated with the main cardiovascular parameters. We conclude that the PAOI in CTA is helpful for assessing risk stratification in patients with APE, which contributes to the selection of both the treatment plan and prognostic evaluation.

ACR Appropriateness Criteria® Acute Chest Pain-Suspected Pulmonary Embolism

Pulmonary embolism (PE) remains a common and important clinical condition that cannot be accurately diagnosed on the basis of signs, symptoms, and history alone. The diagnosis of PE has been facilitated by technical advancements and multidetector CT pulmonary angiography, which is the major diagnostic modality currently used. Ventilation and perfusion scans remain largely accurate and useful in certain settings. Lower-extremity ultrasound can substitute by demonstrating deep vein thrombosis; however, if negative, further studies to exclude PE are indicated. In all cases, correlation with the clinical status, particularly with risk factors, improves not only the accuracy of diagnostic imaging but also overall utilization. Other diagnostic tests have limited roles. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Clinical Significance of Late Phase of Lung Perfusion Blood Volume (Lung Perfusion Blood Volume) Quantified by Dual-Energy Computed Tomography in Patients With Pulmonary Thromboembolism

PURPOSE

Using dual-energy computed tomography (DECT), we quantified the lung perfusion blood volume (PBV) in the late phase, which may reflect both the pulmonary artery and systemic collateral flow. We then investigated the clinical significance of late-phase lung PBV values.

MATERIALS AND METHODS

We retrospectively studied 206 patients (266 scans) who underwent early-phase and late-phase DECT. The patients were divided into 2 groups depending on whether or not they had pulmonary thromboembolism (PTE) (n=94 and 112). Patients with PTE were further divided into 2 subgroups, depending on whether they had acute PTE or chronic PTE (n=66 and 28). Pulmonary artery enhancement (PAenh) was measured on DECT. We then calculated the [lung PBV/PAenh] ratio in all patients during both the early and late phases for adjustment of timing.

RESULTS

The [late-phase lung PBV/PAenh] ratio was 0.092±0.029 in the group with PTE and 0.108±0.030 in the group without PTE, showing a significant difference between the 2 groups (P<0.0001). The [early-phase lung PBV values/PAenh]/[late-phase lung PBV values/PAenh] ratio was 0.68±0.19 and 0.84±0.20, respectively, also showing a significant difference between the 2 groups (P<0.0001). Finally, the [early-phase lung PBV/PAenh]/[late-phase lung PBV/PAenh] ratio was 0.71±0.19 in patients with acute PTE and 0.56±0.16 in patients with chronic PTE, and there was a significant difference between these 2 subgroups (P=0.0004).

CONCLUSIONS

It may be useful to determine late-phase lung PBV values in patients with PTE, because this parameter may reflect the systemic collateral flow, which is increased in chronic PTE.

Assessment of Right Ventricular Strain by Computed Tomography Versus Echocardiography in Acute Pulmonary Embolism

BACKGROUND

Right ventricular strain (RVS) identifies patients at risk of hemodynamic deterioration from pulmonary embolism (PE). Our hypothesis was that chest computed tomography (CT) can provide information about RVS analogous to transthoracic echocardiography (TTE) and that RVS on CT is associated with adverse outcomes after PE.

METHODS

Consecutive emergency department patients with acute PE were prospectively enrolled and clinical, biomarker, and imaging data were recorded. CTs were overread by two radiologists. We compared diagnoses of RVS on CT (defined as right ventricle:left ventricle ratio ≥ 0.9 or interventricular septal bowing) to echocardiography (defined as right ventricular hypokinesis, right ventricular dilatation, or interventricular septal bowing). We calculated the test characteristics (with 95% confidence interval) of CT and TTE for a composite outcome of severe clinical deterioration, thrombolysis/thrombectomy, or death within 5 days.

RESULTS

A total of 298 patients were enrolled; 274 had CT and 118 had formal TTE. Of the 104 patients who had both CT and TTE, the mean (±SD) age was 58 (±17) years; 50 (48%) were female and 88 (85%) were Caucasian. Forty-two (40%) had RVS by TTE and 75 (72%) had RVS by CT. CT and TTE agreed on the presence or absence of RVS in 61 (59%) cases (κ = 0.24). Using TTE as criterion standard, the test characteristics of CT for RVS were as follows: sensitivity = 88%, specificity = 39%, positive predictive value = 49%, and negative predictive value = 83%. Fourteen (13%) patients experienced severe clinical deterioration or required hospital-based intervention within 5 days. This occurred in 30% of patients with RVS on both TTE and CT, 20% of patients with RVS on TTE alone, 3% of patients with RVS on CT alone, and 4% of patients without RVS on either modality.

CONCLUSIONS

In acute PE, CT is highly sensitive but only moderately specific for RVS compared to TTE. RVS on both CT and TTE predicts more events than either modality alone. TTE confers additional positive prognostic value compared to CT in predicting post-PE clinical deterioration.

Relation Among Clot Burden, Right-Sided Heart Strain, and Adverse Events After Acute Pulmonary Embolism

Computed tomography pulmonary angiogram (CTPA) provides a volumetric assessment of clot burden in acute pulmonary embolism (PE). However, it is unclear if clot burden is associated with right-sided heart strain (RHS) or adverse clinical events (ACE). We prospectively enrolled Emergency Department patients with PE (in CTPA) from 2008 to 2011. We assigned 1 to 9 points as clot burden score, based on whether emboli were saddle, central, lobar, segmental, and subsegmental. We evaluated a novel score (the "CT-PASS") based on the sum (in millimeters) of the largest filling defects in the right and left pulmonary vasculature. Our primary outcome was RHS, defined by imaging (echocardiography or CTPA) or cardiac biomarkers. Our secondary outcomes included 5-day ACE. We included 271 patients (50% women), with a mean age of 59 ± 17 years. Based on CTPA, 131 patients (48%) had central PE (clot burden score ≥5 points). The median CT-PASS was 9.1 mm (interquartile range 4.9 to 16.4). In univariate analysis, higher clot burden (highest quartile CT-PASS) was associated with RHS (p = 0.003). In multivariate analysis, after adjusting for RHS, age, and gender, central PE (odds ratio [OR] 2.92, 95% confidence interval [CI] 1.10 to 7.81) and CT-PASS >20 mm (OR 3.54, 95% CI 1.39 to 8.97) were significantly associated with ACE. However, this association of central PE with ACE was not statistically significant after excluding patients with shock index >1 (OR 2.56, 95% CI 0.62 to 10.64). In conclusion, highest quartile CT-PASS was associated with RHS and central PE and ACE, but this association was not statistically significant in hemodynamically stable PE [corrected].

Central Versus Peripheral Pulmonary Embolism: Analysis of the Impact on the Physiological Parameters and Long-term Survival

Background:

Studies aimed at assessing whether the emboli lodged in the central pulmonary arteries carry a worse prognosis than more peripheral emboli have yielded controversial results.

Aims:

To explore the impact on survival and long-term prognosis of central pulmonary embolism.

Patients and Methods:

Consecutive patients diagnosed with acute symptomatic pulmonary embolism by means of computed tomography (CT) angiography were evaluated at episode index and traced through the computed system of clinical recording and following-up. Central pulmonary embolism was diagnosed when thrombi were seen in the trunk or in the main pulmonary arteries and peripheral pulmonary embolism when segmental or subsegmental arteries were affected.

Results:

A total of 530 consecutive patients diagnosed with pulmonary embolism were evaluated; 255 patients had central pulmonary embolism and 275 patients had segmental or subsegmental pulmonary embolism. Patients with central pulmonary embolism were older, had higher plasma levels of N-terminal of the prohormone brain natriuretic peptide (NT-ProBNP), troponin I, D-dimer, alveolar-arterial gradient, and shock index (P < .001 for each one). Patients with central pulmonary embolism had an all-cause mortality of 40% while patients with segmental or subsegmental pulmonary embolism (PE) had an overall mortality of 27% and odds ratio of 1.81 [confidence interval (CI) 95% 1.16-1.9]. Survival was lower in patients with central PE than in patients with segmental or subsegmental pulmonary embolism, even after avoiding confounders (P = .018).

Conclusions:

Apart from a greater impact on hemodynamics, gas exchange, and right ventricular dysfunction, central pulmonary embolism associates a shorter survival and an increased long-term mortality.

Pulmonary hypertension and right ventricular dysfunction in patients with left to right shunt coronary artery fistula: evaluation with cardiac CT

In this study, we aimed to evaluate whether patients with left to right shunt coronary artery fistula (LRSCAF) are predisposed to developing pulmonary hypertension and right ventricular dysfunction compared with healthy individuals. The value of cardiac CT findings in determining the necessity of intervention for these patients was investigated. We retrospectively studied 19 patients with LRSCAF and 19 healthy patients. Several parameters were observed on cardiac CT by two radiologists, including pulmonary trunk diameter (PA diameter), right ventricular diameter (RVD), left ventricular diameter (LVD), RVD/LVD ratio, septal bowing and CT score of right ventricular dysfunction (CSRVD). Data from both groups were compared. The inter- and intra-observer variabilities and correlations were examined. The disease group was further divided into intervention (n = 9) and non-intervention (n = 10) groups, and their data were compared. All cardiac CT findings showed significant intra- and inter-observer correlation without significant variability. Mann-Whitney U tests and χ(2) analysis showed that PA diameter, RVD/LVD ratio acquired from two observers, and CSRVD were higher in the disease group than in the control group (all P values < 0.05 for χ(2) and almost all P values < 0.05 for Mann-Whitney U). The RVD/LVD ratio and CSRVD were higher in the intervention group than in the non-intervention group (all P values < 0.05). Receiver operating curve analysis identified RVD/LVD = 1.036 and CSRVD = 3.5 as the best cut-off values to determine the necessity of further intervention. Patients with LRSCAF are more predisposed to pulmonary hypertension and right ventricular dysfunction compared with the normal population. RVD/LVD > 1.0 and CSRVD ≥ 4.0 may determine the necessity of intervention for patients with LRSCAF.

Multidetector computed tomography pulmonary angiography in childhood acute pulmonary embolism

Pulmonary embolism is a life-threatening condition affecting people of all ages. Multidetector row CT pulmonary angiography has improved the imaging of pulmonary embolism in both adults and children and is now regarded as the routine modality for detection of pulmonary embolism. Advanced CT pulmonary angiography techniques developed in recent years, such as dual-energy CT, have been applied as a one-stop modality for pulmonary embolism diagnosis in children, as they can simultaneously provide anatomical and functional information. We discuss CT pulmonary angiography techniques, common and uncommon findings of pulmonary embolism in both conventional and dual-energy CT pulmonary angiography, and radiation dose considerations.

Predictive Value of Computed Tomography in Acute Pulmonary Embolism: Systematic Review and Meta-analysis

BACKGROUND

Many computed tomography (CT) parameters have been proposed as potential predictors of outcome in acute pulmonary embolism. We sought to summarize available evidence on the predictive value of CT severity parameters for short-term clinical outcome in pulmonary embolism.

METHODS

We searched PubMed and EMBASE through February 2014 for studies that reported on the association between CT parameters of acute pulmonary embolism severity and short-term (≤6 months) clinical outcome. Risk estimates for quantitative parameters of right ventricular (RV) dysfunction (abnormally increased RV/left ventricular [LV] diameter ratio on transverse sections and 4-chamber views), qualitative parameters of RV dysfunction (abnormal septal morphology and contrast reflux), thrombus load, and central thrombus location were derived using random effect regression analysis. Meta-regression analysis was performed to quantify and explain study heterogeneity.

RESULTS

A total of 49 studies with 13,162 patients with acute pulmonary embolism (median age of 61 years, 55.1% were women) who underwent diagnostic CT imaging were included in the analysis. An abnormally increased RV/LV diameter ratio measured on transverse sections was associated with an approximately 2.5-fold risk for all-cause mortality (pooled odds ratio [OR], 2.5; 95% confidence interval [CI], 1.8-3.5) and adverse outcome (OR, 2.3; 95% CI, 1.6-3.4) and a 5-fold risk for pulmonary embolism-related mortality (OR, 5.0; 95% CI, 2.7-9.2). Thrombus load (OR, 1.6, 95% CI, 0.7-3.9; P = .2896) and central location (OR, 1.7; 95% CI, 0.7-4.2; P = .2609) were not predictive for all-cause mortality, although both were associated with adverse clinical outcome.

CONCLUSIONS

Across all end points, the RV/LV diameter ratio on transverse CT sections has the strongest predictive value and most robust evidence base for adverse clinical outcomes in patients with acute pulmonary embolism.

Quantitative lung perfused blood volume imaging on dual-energy CT: capability for quantitative assessment of disease severity in patients with acute pulmonary thromboembolism

BACKGROUND

Regional iodine distribution assessment on dual-energy computed tomography (DECT) has been suggested as useful for management of acute pulmonary thromboembolism (APTE) patients. However, no reported studies have made a direct comparison between quantitatively assessed DECT and right-to-left ventricular (RV/LV) ratio on CT for differentiation of right heart dysfunction (RHD) from non-right heart dysfunction (NRHD) in APTE patients.

PURPOSE

To determine the capability of DECT for differentiation of RHD from NRHD in APTE patients.

MATERIAL AND METHODS

Thirteen APTE patients underwent DECT and echocardiography at onset of APTE. Patients were divided into RHD (n = 7) and NRHD (n = 6) groups based on echocardiography. A normalized lung perfused blood volume map was generated, and two kinds of overall perfusion (OP) index were determined, one placed over each lung field (OP index A) and as the average from six regions of interest (ROIs) placed over each lung field (OP index B). The heterogeneity index was also determined as the standard deviation for the six ROIs. RV/LV ratio evaluations were also performed. To assess differences between the two groups, each index was statistically compared with the Mann-Whitney U test. The receiver-operating curve-based positive test was then performed to determine the feasible threshold value for dividing patients into the two groups. Finally, differentiation capabilities of the indexes were compared using McNemar's test.

RESULTS

Significant differences between the two groups were found for both OP indexes and RV/LV ratio (P < 0.05). For each of the feasible threshold values, accuracy of each OP index with and without RV/LV ratio was better than that of the RV/LV ratio.

CONCLUSION

Quantitative DECT has good potential for differentiation of APTE patients with and without right heart dysfunction.

Quantification of lung perfusion blood volume with dual-energy CT: assessment of the severity of acute pulmonary thromboembolism

OBJECTIVE

The purpose of this study was to evaluate the usefulness of quantification of lung perfused blood volume (PBV) with dual-energy CT (DECT) for assessment of the severity of acute pulmonary thromboembolism (PTE).

MATERIALS AND METHODS

We retrospectively analyzed the records of 72 patients with PTE and 168 without PTE who underwent DECT. The PTE patients were divided into high-, intermediate-, and low-risk groups based on clinical symptoms and right ventricular dysfunction. Correlations between quantification of whole-lung PBV and clinical severity were evaluated. Also evaluated was the relation between quantification of whole-lung PBV and right-to-left ventricular diameter ratio on CT images, which was used as an indicator of right ventricular dysfunction.

RESULTS

In the PTE and control groups, the whole-lung PBVs were 27.6 ± 7.9 and 29.9 ± 6.8 HU with a significant difference between them (p < 0.0281). In the high-, intermediate-, and low-risk PTE groups, the whole-lung PBVs were 16.0 ± 2.9, 21.0 ± 4.2, and 31.4 ± 5.8 HU with a significant difference between them (p < 0.05). There was no significant difference in whole-lung PBV between the control group and the low-risk PTE group, but there was a significant difference between the control group and the other two PTE groups. In PTE patients, whole-lung PBV had negative correlation with right-to-left ventricular diameter ratio (R = -0.567, p < 0.001).

CONCLUSION

Quantification of lung PBV with DECT is useful for assessment of the clinical severity of PTE and can be used as an indicator of right ventricular dysfunction.

Prognostic role of embolic burden assessed at computed tomography angiography in patients with acute pulmonary embolism: systematic review and meta-analysis

BACKGROUND

In patients with acute pulmonary embolism (PE), risk stratification is indicated for tailoring of both diagnostic strategies and acute treatment. Whether embolic burden assessed at computed tomography (CT) angiography has a role in risk stratification in these patients is debated.

OBJECTIVE

To systematically review and perform a meta-analysis to evaluate the role of CT-assessed burden associated with embolic obstruction and embolic localization in the prognostic stratification of patients with acute PE.

METHODS

We performed a systematic search in EMBASE and MEDLINE up until 30 June 2013. Studies reporting on the 30-day outcome of patients with confirmed PE and CT-assessed embolic burden were included. The study outcome was death.

RESULTS

Thirty studies reporting on the prognostic value of CT-assessed embolic burden met the inclusion criteria for this systematic review; of these, 19 were included in the meta-analysis. Five studies (2215 patients) were included in the analysis of localization: an association between embolus localization in the central arteries and 30-day mortality was found after heterogeneity was resolved (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.29-3.89, I(2)  = 0%). No correlation was observed between obstruction index (according to the Qanadli scoring system) and 30-day mortality after heterogeneity was reduced (16 studies, 3884 patients, OR 1.22, 95% CI 0.99-1.51, I(2)  = 27%).

CONCLUSION

Localization of emboli assessed at CT angiography can be used for risk stratification in patients with acute PE. Moreover, no correlation was observed between obstruction index and prognosis.

Non-invasive evaluation of hemodynamics in pulmonary hypertension by a Septal angle measured by computed tomography pulmonary angiography: Comparison with right-heart catheterization and association with N-terminal pro-B-type natriuretic peptide

The septal angle, an angle between the interventricular septum and the line connecting the sternum midpoint and thoracic vertebral spinous process, as measured by computed tomographic pulmonary angiography (CTPA), has been observed to be increased in patients with pulmonary hypertension (PH), but its meaning remains unclear. The aim of this study was to investigate the potential role of the septal angle in evaluating hemodynamics and its association with N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with PH. Patients with PH (n=106), including 76 with chronic thromboembolic pulmonary hypertension (CTEPH) and 30 with pulmonary artery hypertension (PAH), were retrospectively reviewed. The patients underwent CTPA prior to right-heart catheterization. The septal angle was measured on transversal CTPA images. Hemodynamic parameters were evaluated by right-heart catheterization. The level of plasma NT-proBNP was measured by enzyme-linked sandwich immunoassay. The septal angle had a moderate correlation with cardiac output (CO; r=−0.535, P=0.000) and a high correlation with pulmonary vascular resistance (PVR; r=0.642, P=0.000). The mean level of NT-proBNP in PH was 1,716.09±1,498.30 pg/ml, which correlated with the septal angle (r=0.693, P=0.000). In a stepwise forward regression analysis, the Septal angle was entered into the final equation for predicting PVR, leading to the following equation: PVR = 28.256 × Septal angle - 728.72. In CTEPH, the Septal angle strongly correlated with NT-proBNP (r=0.668, P=0.000) and PVR (r=0.676, P=0.000). In PAH, the Septal angle strongly correlated with NT-proBNP (r=0.616, P=0.003) and PVR (r=0.623, P=0.000). The CTPA-derived Septal angle is a superior predictor for evaluating and monitoring the level of NT-proBNP and PVR in patients with PH.

Multidetector CT scan for acute pulmonary embolism: embolic burden and clinical outcome

BACKGROUND

In patients with acute pulmonary embolism (PE), the correlation between the embolic burden assessed by multidetector CT (MDCT) scan and clinical outcomes remains unclear. Patients with symptomatic acute PE diagnosed based on MDCT angiography were included in a multicenter study aimed at assessing the prognostic role of the embolic burden evaluated with MDCT scan.

METHODS

Embolic burden was assessed as (1) localization of the emboli as central (saddle or at least one main pulmonary artery), lobar, or distal (segmental or subsegmental arteries) and (2) the obstruction index by the scoring system of Qanadli. The primary outcome was 30-day all-cause death or clinical deterioration. Predictors of all-cause death or clinical deterioration were identified by Cox regression statistics.

RESULTS

Overall, 579 patients were included in the study; 60 (10.4%) died or had clinical deterioration at 30 days. Central localization of emboli was not associated with all-cause death or clinical deterioration (hazard ratio [HR], 2.42; 95% CI, 0.77-7.59; P 5 .13). However, in 516 hemodynamically stable patients, central localization of emboli (HR, 8.3; 95% CI, 1.0-67; P 5 .047) was an independent predictor of all-cause death or clinical deterioration, whereas distal emboli were inversely associated with these outcome events (HR, 0.12; 95% CI, 0.015-0.97; P 5 .047). No correlation was found between obstruction index (evaluated in 448 patients) and all-cause death or clinical deterioration in the overall study population and in the hemodynamically stable patients.

CONCLUSIONS

In hemodynamically stable patients with acute PE, central emboli are associated with an increased risk for all-cause death or clinical deterioration. This risk is low in patients with segmental or subsegmental PE.

Pleural effusion in pulmonary embolism

PURPOSE OF REVIEW

Pulmonary embolism is a common and potentially lethal disease that recurs frequently and is associated with long-term impairment and suffering. Patients with pulmonary embolism are at risk of death, recurrence of embolism, or chronic morbidity. Appropriate therapy can reduce the incidence of all. Pulmonary embolism is the most commonly overlooked disorder in patients with pleural effusion. Recent findings of pleural effusions due to pulmonary embolism are discussed in this review.

RECENT FINDINGS

The presence of pleuritic chest pain in a patient with a pleural effusion is highly suggestive of pulmonary embolism. Nearly all pleural effusions due to pulmonary embolism are exudates, frequently hemorrhagic, and with a marked mesothelial hyperplasia. Patients with a pleural effusion are likely to have an embolus in the central, lobar, segmental, or subsegmental pulmonary arteries and these are the regions in which spiral computed tomography pulmonary angiography (CTPA) can detect an embolus. No specific treatment is required for pleural effusion. The presence of bloody pleural fluid is not a contraindication for the administration of anticoagulant therapy.

SUMMARY

Pulmonary embolism is probably responsible for a significant percentage of undiagnosed exudative pleural effusions. Spiral CTPA is the best way to evaluate the possibility of pulmonary embolism in a patient with a pleural effusion. The treatment protocol of the patient with pleural effusion secondary to pulmonary embolism is the same as that for any patient with pulmonary embolism.

Cardiothoracic CT: one-stop-shop procedure? Impact on the management of acute pulmonary embolism

In the treatment of pulmonary embolism (PE) two groups of patients are traditionally identified, namely the hemodynamically stable and instable groups. However, in the large group of normotensive patients with PE, there seems to be a subgroup of patients with an increased risk of an adverse outcome, which might benefit from more aggressive therapy than the current standard therapy with anticoagulants. Risk stratification is a commonly used method to define subgroups of patients with either a high or low risk of an adverse outcome. In this review the clinical parameters and biomarkers of myocardial injury and right ventricular dysfunction (RVD) that have been suggested to play an important role in the risk stratification of PE are described first. Secondly, the use of more direct imaging techniques like echocardiography and CT in the assessment of RVD are discussed, followed by a brief outline of new imaging techniques. Finally, two risk stratification models are proposed, combining the markers of RVD with cardiac biomarkers of ischemia to define whether patients should be admitted to the intensive care unit (ICU) and/or be given thrombolysis, admitted to the medical ward, or be safely treated at home with anticoagulant therapy.

Subjective assessment of right ventricle enlargement from computed tomography pulmonary angiography images

To retrospectively evaluate prognostic accuracy of subjective assessment of right ventricle (RV) enlargement on CT pulmonary angiography (CTPA) images in comparison with objective measures of RV enlargement in patients with acute pulmonary embolism (PE). For 200 consecutive patients with acute PE, two readers blinded to patient outcomes subjectively determined whether the maximum RV diameter was greater than that of the left ventricle (LV) using axial CTPA images. For the objective measurements, RV/LV diameter ratios were calculated using axial images and 4-chamber reformatted images. For all assessments, sensitivities and specificities for predicting PE-related death within 30-days and a composite outcome including PE-related death or the need for intensive therapies were compared. The agreement between two readers was 91.5% (kappa = 0.83) and all other assessments had pair-wise agreement over 75% (kappa = 0.53-0.72). There was no significant difference in sensitivity between the subjective and objective methods for predicting both outcomes. The specificity for subjective RV enlargement (55.4-67.7%) was significantly higher than objective measures (45.8-53.1%), except for the 4-chamber views where, for one reader, the specificity of the subjective evaluation was higher but did not reach statistical significance. Complex measurements of RV/LV diameter ratios may not be needed to maximize the prognostic value from CTPA. The radiologist who interprets the CTPA images should report RV enlargement when the RV diameter subjectively appears larger than the LV.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

Predictors of clinical outcome in acute pulmonary embolism: Correlation of CT pulmonary angiography with clinical, echocardiography and laboratory findings

RATIONALE AND OBJECTIVES

The aims of this study were to retrospectively evaluate whether computed tomographic (CT) parameters were predictors of in-hospital mortality within 30 days of CT imaging and to compare CT parameters with clinical, echocardiographic, and laboratory findings in patients with acute pulmonary embolism (PE).

MATERIALS AND METHODS

A total of 122 patients (61 women, 61 men; mean age, 64 ± 15 years) with CT scans positive for acute PE were reviewed. Two independent readers who were blinded to clinical outcomes scored pulmonary artery obstructions, evaluated cardiovascular measurements, and assessed qualitative findings. Reports of echocardiographic, clinical, and laboratory findings and clinical outcome were reviewed. Results were correlated with patient outcomes using Wilcoxon's rank-sum, χ², and Student's t tests. Logistic regression analyses were performed to determine predictors of patient outcomes.

RESULTS

Thirteen patients (11%) died related to PE within 30 days in the hospital. There were significant differences in the ratio of arterial partial pressure of oxygen to inspired fraction of oxygen and in heart rate between survivors and nonsurvivors (P < .05). No CT or echocardiographic predictor was associated with mortality.

CONCLUSIONS

The ratio of arterial partial pressure of oxygen to inspired fraction of oxygen and heart rate strongly predicted mortality due to PE. Neither CT pulmonary angiographic variables nor echocardiography could successfully predict in-hospital mortality in patients with acute PE.