Left Atrial Area and Right Ventricle Dimensions in Non-gated Axial Chest CT can Differentiate Pulmonary Hypertension Due to Left Heart Disease from Other Causes

Adjusting Atrial Size Parameters for Body Surface Area: Does it Affect the Association With Pulmonary Embolism-related Adverse Events?

PURPOSE

Small left atrial (LA) volume was recently reported to be one of the best predictors of acute pulmonary embolism (PE)-related adverse events (AE). There is currently no data available regarding the impact that body surface area (BSA)-indexing of atrial measurements has on the association with PE-related adverse events. Our aim is to assess the impact of indexing atrial measurements to BSA on the association between computed tomography (CT) atrial measurements and AE.

MATERIALS AND METHODS

Retrospective study (IRB: 2015P000425). A database of hospitalized patients with acute PE diagnosed on CT pulmonary angiography (CTPA) between May 2007 and December 2014 was reviewed. Right and left atrial volume, largest axial area, and axial diameters were measured. Patients undergo both echocardiographies (from which the BSA was extracted) and CTPAs within 48 hours of the procedure. The patient's body weight was measured during each admission. LA measurements were correlated to AE (defined as the need for advanced therapy or PE-related mortality at 30 days) before and after indexing for BSA. The area under the ROC curve was calculated to determine the predictive value of the atrial measurements in predicting AE.

RESULTS

The study included 490 acute PE patients; 62 (12.7%) had AE. There was a significant association of reduced BSA-indexed and non-indexed LA volume (both <0.001), area (<0.001 and 0.001, respectively), and short-axis diameters (both <0.001), and their respective RA/LA ratios (all <0.001) with AE. The AUC values were similar for BSA-indexed and non-indexed LA volume, diameters, and area with LA volume measurements being the best predictor of adverse outcomes (BSA-indexed AUC=0.68 and non-indexed AUC=0.66), followed by non-indexed LA short-axis diameter (indexed AUC=0.65, non-indexed AUC=0.64), and LA area (indexed AUC=0.64, non-indexed AUC=0.63).

CONCLUSION

Adjusting for BSA does not substantially affect the predictive ability of atrial measurements on 30-day PE-related adverse events, and therefore, this adjustment is not necessary in clinical practice. While LA volume is the better predictor of AE, LA short-axis diameter has a similar predictive value and is more practical to perform clinically.

Evidence for Left Atrial Volume Being an Indicator of Adverse Events in Patients With Acute Pulmonary Embolism: Retrospective Case-control Pilot Study

PURPOSE

To assess the association between computed tomography pulmonary angiography (CTPA) atrial measurements and both 30-day pulmonary embolism (PE)-related adverse events and mortality, and non-PE-related mortality, and to identify the best predictors of these outcomes by comparing atrial measurements and widely used clinical and imaging variables.

PATIENTS AND METHODS

Retrospective single-center pilot study. Acute PE patients diagnosed on CTPA who also had a transthoracic echocardiogram, electrocardiogram, and troponin T were included. CTPA left atrial (LA) and right atrial (RA) volume and short-axis diameter were measured and compared between outcome groups, along with right ventricular/left ventricular diameter ratio, interventricular septal bowing, tricuspid annular plane systolic excursion, electrocardiogram, and troponin T.

RESULTS

A total of 350 patients. LA volume and diameter were associated with PE-related adverse events (P≤0.01). LA volume was the only atrial measurement associated with PE-related mortality (P=0.03), with no atrial measurements associated with non-PE-related mortality. Troponin was most associated with PE-related adverse events and mortality (both area under the curve [AUC]=0.77). On multivariate analysis, combination models did not greatly improve PE-related adverse events prediction compared with troponin alone. For PE-related mortality, the best models were the combination of troponin, age, and either LA volume (AUC=0.86) or diameter (AUC=0.87).

CONCLUSION

Among patients with acute PE, CTPA LA volume is the only imaging parameter associated with PE-related mortality and is the best imaging predictor of this outcome. Reduced CTPA LA volume and diameter, along with increased RA/LA volume and diameter ratios, are significantly associated with 30-day PE-related adverse events, but not with non-PE-related mortality.

Diagnostic accuracy of automated 3D volumetry of cardiac chambers by CT pulmonary angiography for identification of pulmonary hypertension due to left heart disease

OBJECTIVES

To assess diagnostic accuracy of automated 3D volumetry of cardiac chambers based on computed tomography pulmonary angiography (CTPA) for the differentiation of pulmonary hypertension due to left heart disease (group 2 PH) from non-group 2 PH compared to manual diameter measurements.

METHODS

Patients with confirmed PH undergoing right heart catheterisation and CTPA within 100 days for diagnostic workup of PH between August 2013 and February 2016 were included in this retrospective, single-centre study. Automated 3D segmentation of left atrium, left ventricle, right atrium and right ventricle (LA/LV/RA/RV) was performed by two independent and blinded radiologists using commercial software. For comparison, axial diameters were manually measured. The ability to differentiate group 2 PH from non-group 2 PH was assessed by means of logistic regression.

RESULTS

Ninety-one patients (median 67.5 years, 44 women) were included, thereof 19 patients (20.9%) classified as group 2 PH. After adjustment for age, sex and mean pulmonary arterial pressure, group 2 PH was significantly associated with larger LA volume (p < 0.001), larger LV volume (p = 0.001), lower RV/LV volume ratio (p = 0.04) and lower RV/LA volume ratio (p = 0.003). LA volume demonstrated the highest discriminatory ability to identify group 2 PH (AUC, 0.908; 95% confidence interval, 0.835-0.981) and was significantly superior to LA diameter (p = 0.009). Intraobserver and interobserver agreements were excellent for all volume measurements (intraclass correlation coefficients 0.926-0.999, all p < 0.001).

CONCLUSIONS

LA volume quantified by automated, CTPA-based 3D volumetry can differentiate group 2 PH from other PH groups with good diagnostic accuracy and yields significantly higher diagnostic accuracy than left atrial diameter.

KEY POINTS

• Automated cardiac chamber volumetry using non-gated CT pulmonary angiography can differentiate pulmonary hypertension due to left heart disease from other causes with good diagnostic accuracy. • Left atrial volume yields significantly higher diagnostic accuracy than left atrial axial diameter for identification of pulmonary hypertension due to left heart disease without time-consuming manual processing.

Utility of Automated Cardiac Chamber Volumetry by Non-Gated CT Pulmonary Angiography for Detection of Pulmonary Hypertension Using the 2018 Updated Hemodynamic Definition

BACKGROUND: Noninvasive tests for pulmonary hypertension (PH) are needed to help select patients for diagnostic right heart catheterization (RHC). CT pulmonary angiography (CTPA) is commonly performed for suspected PH. OBJECTIVE: To assess the utility of CTPA-based cardiac chamber volumetric measurements for diagnosis of PH in comparison with echocardiographic and conventional CTPA parameters, using as reference the 2018 updated hemodynamic definition. METHODS: This retrospective study included 109 patients (median age, 68 years; 72 women, 37 men) who underwent non-gated CTPA, echocardiography, and RHC for workup of suspected PH between August 2013 and February 2016. Two radiologists independently used automated 3D segmentation software to determine volumes of the right ventricle (RV), right atrium (RA), left ventricle (LV), and left atrium (LA), and measured axial diameters of cardiac chambers, main pulmonary artery, and ascending aorta. Interobserver agreement was assessed, and mean values were obtained; one observer repeated volumetric measurements to assess intraobserver agreement. ROC analysis was used to assess diagnostic performance for detection of PH. A multivariable binary logistic regression model was established. RESULTS: A total of 60/109 patients had PH. Intra- and interobserver agreement were excellent for all volume measurements (intraclass correlation coefficients, 0.935-0.999). In patients with, versus without, PH, RV volume was 172.6 versus 118.1 ml, and RA volume was 130.2 versus 77.0 ml (both p<.05). Cardiac chamber measurements with highest AUC for PH were RV/LV volume ratio and RA volume (both 0.791). Significant predictors of PH after adjustment for age, sex, and body surface area included RV volume per 10 ml [odds ratio (OR)=1.21], RA volume per 10 ml (OR=1.27), RV/LV volume ratio (OR=2.91), and RA/LA volume ratio (OR=11.22). Regression analysis yielded a predictive model for PH containing two independent predictors, echocardiographic pulmonary arterial systolic pressure and CTPA-based RA volume; the model had AUC 0.898, sensitivity 83.3%, and specificity 85.7%. CONCLUSION: Automated cardiac chamber volumetry using non-gated CTPA, particularly of the RA, provides incremental utility relative to echocardiographic and conventional CTPA parameters for diagnosis of PH. CLINICAL IMPACT: Automated cardiac chamber volumetry on CTPA may facilitate early nonvinvasive detection of PH, identifying patients warranting further evaluation by RHC.

Cardiac Magnetic Resonance-Derived Indexed Volumes and Volume Ratios of the Cardiac Chambers Discriminating Group 2 Pulmonary Hypertension From Other World Health Organization Groups

OBJECTIVE

The aims of the study were to assess the performance of cardiac magnetic resonance (CMR)-derived cardiac chamber volumes and volume ratios to identify group 2 pulmonary hypertension (PH) patients and to determine their cutoff values with the highest sensitivity and specificity.

METHODS

One hundred six patients underwent CMR, 2 months after the diagnosis of PH by right heart catheterization. We classified patients with pulmonary capillary wedge pressure of greater than 15 mm Hg as group 2 PH. Cardiac chamber volumes indexed to the body surface area and volume ratios were correlated to the type of PH. Their sensitivity and specificity to detect group 2 PH were examined at various cutoff points.

RESULTS

The most appropriate cutoff values to designate group 2 PH patients with high sensitivity and specificity were as follows: left atrium volume index of 54.72 mL/m2 or greater, right ventricle volume/left atrium volume of 2.07 or less, and right atrium volume/left atrium volume of 1.61 or less.

CONCLUSIONS

Cardiac magnetic resonance-derived cardiac chamber volume indices and volume ratios can determine group 2 PH diagnosis with high sensitivity and specificity.

The use of computed tomography pulmonary angiography in the diagnosis of heart failure in the acute setting

BACKGROUND

Heart failure is a clinical diagnosis characterised by non-specific symptoms such as dyspnoea, fatigue and oedema. The aim of this pilot study was to investigate what role computed tomography pulmonary angiography could play in supporting a diagnosis of heart failure when a pulmonary embolism has been excluded.

METHODS

This was a prospective study using the National Integrated Medical Imaging System to assess the potential of computed tomography pulomary angiography (CTPA) as a diagnostic test for heart failure. Consecutive patients were collected from three hospitals of the University of Limerick Hospital Group. We reviewed 230 consecutive CTPA results for cardiac and lung features. Of these, we confirmed which had heart failure by comparison with brain natriuretic peptide (BNP) and echocardiogram criteria. Exclusion criteria included any patients with a diagnosis of pulmonary embolism.

RESULTS

Of these 230 patients, only 24 (10.4%) had both objective and clinical signs of heart failure. The most specific signs were shown to be left ventricular enlargement, left atrial enlargement and right ventricular enlargement, which approximated a specificity of 100% (CI 66.3-100.00%). CTPA was shown to match gold standard echocardiography closely in detecting abnormalities as per chi square; Right ventricular enlargement (value = 5.426 P = 0.02), left atrial enlargement (value = 4.9 P = 0.027) and left ventricular enlargement (value = 5.692 P = 0.017).

CONCLUSION

Findings on CTPA which included left ventricular enlargement, left atrial enlargement and right ventricular enlargement were shown to be specific for a diagnosis of heart failure. CTPA should be used by physicians awaiting echocardiography to help guide treatment in cases of suspected heart failure.

Pulmonary hypertension and chronic lung disease: where are we headed?

Pulmonary hypertension related to chronic lung disease, mainly represented by COPD and idiopathic pulmonary fibrosis, is associated with a worse outcome when compared with patients only affected by parenchymal lung disease. At present, no therapies are available to reverse or slow down the pathological process of this condition and most of the clinical trials conducted to date have had no clinically significant impact. Nevertheless, the importance of chronic lung diseases is always more widely recognised and, along with its increasing incidence, associated pulmonary hypertension is also expected to be growing in frequency and as a health burden worldwide. Therefore, it is desirable to develop useful and reliable tools to obtain an early diagnosis and to monitor and follow-up this condition, while new insights in the therapeutic approach are explored.

Going beyond Cardiomegaly: Evaluation of Cardiac Chamber Enlargement at Non-Electrocardiographically Gated Multidetector CT: Current Techniques, Limitations, and Clinical Implications

Cardiac chamber enlargement is important in the prediction of morbidity and mortality for a multitude of cardiovascular processes. Although non-electrocardiographically (ECG) gated multidetector CT is a commonly used cross-sectional imaging modality to evaluate a litany of cardiothoracic processes, a standardized method for evaluating and reporting cardiac chamber size does not exist. This has led to heterogeneity in the reporting of cardiac enlargement at routine multidetector CT with most readers often using gestalt assessment and the term cardiomegaly, which does not implicate the chamber or chambers that are enlarged. The purpose of this review article is to highlight advantages and limitations of several techniques used to assess cardiac chamber size at non-ECG-gated multidetector CT and to provide readers with reproducible and rapid measurements to determine if cardiac chamber size is present. The long-term aim would be to promote discussions between radiologists and institutions that would result in improved accuracy and decreased variability when commenting on cardiac chamber size. © RSNA, 2019.

Prevalence of pulmonary hypertension in patients with systemic sclerosis and mixed connective tissue disease

Systemic sclerosis (SSc) and mixed connective tissue disease (MCTD) are 2 conditions in which pulmonary hypertension (PH) can develop.We retrospectively analyzed the probability of PH in case of 83 patients (69 SSc and 14 MCTD). The European Society of Cardiology/European Respiratory Society (ESC/ERS) echocardiographic guidelines of 2015 were used for the evaluation.On the basis of an echocardiography, the patients were divided into 2 subgroups: patients with elevated probability of PH (EP) (n = 16) versus the group with a low probability of PH (LP) (n = 67). Of the 16 patients in the EP group, 15 were SSc patients and 1 was an MCTD patient, respectively, that is, 21.7% and 7.1% of all patients. Of the 16 patients with EP, 10 with SSc had right-heart catheterization, which excluded PH in 7 patients; hence, PH was estimated to be 11.6% in the SSc group. The distribution of the individual causes of PH was arterial PH 2.9%, PH associated with interstitial lung disease 4.3%, PH associated with left ventricular disease 1.5%, and PH of unknown origin 2.9%. Further, there was a significant difference between EP and LP in the incidence of the right bundle branch block in standard electrocardiography, left atrial and right ventricular dimension, tricuspid annular plane systolic excursion, and Doppler-derived tricuspid lateral annular systolic velocity (S') in echocardiography.Echocardiography, particularly those evaluating the parameters included in the ESC/ERS guidelines of 2015, appears to be a useful tool in the detection of patients with a high PH probability. Additional tissue Doppler echocardiography seems to be a good option.

CT derived left atrial size identifies left heart disease in suspected pulmonary hypertension: Derivation and validation of predictive thresholds

Background

Patients with pulmonary hypertension due to left heart disease (PH-LHD) have overlapping clinical features with pulmonary arterial hypertension making diagnosis reliant on right heart catheterization (RHC). This study aimed to investigate computed tomography pulmonary angiography (CTPA) derived cardiopulmonary structural metrics, in comparison to magnetic resonance imaging (MRI) for the diagnosis of left heart disease in patients with suspected pulmonary hypertension.

Methods

Patients with suspected pulmonary hypertension who underwent CTPA, MRI and RHC were identified. Measurements of the cardiac chambers and vessels were recorded from CTPA and MRI. The diagnostic thresholds of individual measurements to detect elevated pulmonary arterial wedge pressure (PAWP) were identified in a derivation cohort (n = 235). Individual CT and MRI derived metrics were tested in validation cohort (n = 211).

Results

446 patients, of which 88 had left heart disease. Left atrial area was a strong predictor of elevated PAWP>15 mm Hg and PAWP>18 mm Hg, area under curve (AUC) 0.854, and AUC 0.873 respectively. Similar accuracy was also identified for MRI derived LA volume, AUC 0.852 and AUC 0.878 for PAWP > 15 and 18 mm Hg, respectively. Left atrial area of 26.8 cm² and 30.0 cm² were optimal specific thresholds for identification of PAWP > 15 and 18 mm Hg, had sensitivity of 60%/53% and specificity 89%/94%, respectively in a validation cohort.

Conclusions

CTPA and MRI derived left atrial size identifies left heart disease in suspected pulmonary hypertension with high specificity. The proposed diagnostic thresholds for elevated left atrial area on routine CTPA may be a useful to indicate the diagnosis of left heart disease in suspected pulmonary hypertension.

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Routine CTPA can diagnose left heart disease in suspected pulmonary hypertension.

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Complex multiparameter models do not improve LHD diagnosis.

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Highly specific thresholds have been derived and validated.

Left Atrium Maximal Axial Cross-Sectional Area is a Specific Computed Tomographic Imaging Biomarker of World Health Organization Group 2 Pulmonary Hypertension

PURPOSE

Left heart disease is associated with left atrial enlargement and is a common cause of pulmonary hypertension (PH). We investigated the relationship between left atrium maximal axial cross-sectional area (LA-MACSA), as measured on chest computed tomography (CT), and PH due to left heart disease (World Health Organization group 2) in patients with right heart catheterization-proven PH.

MATERIALS AND METHODS

A total of 165 patients with PH who had undergone right heart catheterization with pulmonary artery pressure and pulmonary capillary wedge pressure (PCWP) measurements and nongated chest CTs were included. LA-MACSA, LA anterior-posterior, and LA transverse measurements were independently obtained using the hand-drawn region-of-interest and distance measurement tools on standard PACS by 2 blinded cardiothoracic radiologists. Nonparametric statistical analyses and receiver operating characteristic curve were performed.

RESULTS

Forty-three patients had group 2 PH (PCWP>15 mm Hg), and 122 had nongroup 2 PH (PCWP≤15 mm Hg). Median LA-MACSA was significantly different between the group 2 PH and nongroup 2 PH patients (2312 vs. 1762 mm, P<0.001). Interobserver concordance correlation for LA-MACSA was high at 0.91 (P<0.001). At a threshold of 2400 mm, LA-MACSA demonstrated 93% specificity for classifying group 2 PH (area under the curve, 0.73; P<0.001).

CONCLUSIONS

LA-MACSA is a readily obtainable and reproducible measurement of left atrial enlargement on CT and can distinguish between group 2 and nongroup 2 PH with high specificity.

Left Atrium Measurements via Computed Tomography Pulmonary Angiogram as a Predictor of Diastolic Dysfunction

PURPOSE

Left atrium (LA) enlargement on echocardiography may be an indicator of diastolic dysfunction (DD). It is not well known if computed tomography pulmonary angiography (CTPA) can detect DD.

METHODS

A total of 127 patients who underwent both CTPA and echo within 48 hours were analyzed retrospectively. Left atrium diameters from CTPA were correlated with echo and evaluated against degrees of DD. Computed tomography pulmonary angiography pulmonary artery (PA)/aorta ratio was analyzed as a tool to detect pulmonary hypertension.

RESULTS

There were 42% of patients who had DD. There was a strong correlation between LA size on CTPA and echo (r = 0.78). An LA greater than 4.0 cm gave a sensitivity of 68.1% and specificity of 73.9% for DD detection. A PA/aorta cutoff greater than 0.84 yielded a sensitivity of 84% and specificity of 33% for pulmonary hypertension.

CONCLUSIONS

Computed tomography pulmonary angiography measurements of LA and PA/aorta ratio correlate strongly with equivalent findings on echo. We suggest that LA and PA/aorta measurements be included on chest CTPA reports.

Identification of Pulmonary Hypertension Caused by Left-Sided Heart Disease (World Health Organization Group 2) Based on Cardiac Chamber Volumes Derived From Chest CT Imaging

BACKGROUND

Evaluations of patients with pulmonary hypertension (PH) commonly include chest CT imaging. We hypothesized that cardiac chamber volumes calculated from the same CT scans can yield additional information to distinguish PH related to left-sided heart disease (World Health Organization group 2) from other PH subtypes.

METHODS

Patients who had PH confirmed by right heart catheterization and contrast-enhanced chest CT studies were enrolled in this retrospective multicenter study. Cardiac chamber volumes were calculated using automated segmentation software and compared between group 2 and non-group 2 patients with PH.

RESULTS

This study included 114 patients with PH, 27 (24%) of whom were classified as group 2 based on their pulmonary capillary wedge pressure. Patients with group 2 PH exhibited significantly larger median left atrial (LA) volumes (118 mL vs 63 mL; P < .001), larger median left ventricular (LV) volumes (90 mL vs 76 mL; P = .02), and smaller median right ventricular (RV) volumes (173 mL vs 210 mL; P = .005) than did non-group 2 patients. On multivariate analysis adjusted for age, sex, and mean pulmonary arterial pressure, group 2 PH was significantly associated with larger median LA and LV volumes (P < .001 and P = .008, respectively) and decreased volume ratios of RA/LA, RV/LV, and RV/LA (P = .001, P = .004, and P < .001, respectively). Enlarged LA volumes demonstrated a high discriminatory ability for group 2 PH (area under the curve, 0.92; 95% CI, 0.870-0.968).

CONCLUSIONS

Volumetric analysis of the cardiac chambers from nongated chest CT scans, particularly with findings of an enlarged left atrium, exhibited high discriminatory ability for identifying patients with PH due to left-sided heart disease.

CTA-derived left to right atrial size ratio distinguishes between pulmonary hypertension due to heart failure and idiopathic pulmonary arterial hypertension

BACKGROUND/OBJECTIVES

Assessing atrial sizes by routine non-gated CT-angiography (CTA) could be of value in discriminating between pulmonary hypertension (PH) due to heart failure with preserved ejection fraction (HFpEF) and idiopathic pulmonary arterial hypertension (IPAH). We aimed to determine how left (LA) and right atrial (RA) sizes on non-gated CTA can help discriminate between these patients.

METHODS AND RESULTS

In an initial study, CMR was used in 15 IPAH and 15 PH-HFpEF patients to determine LA- and RA size throughout the cardiac cycle. While significant variations were noted in LA size over the cardiac cycle, the calculated ratio of left over right atrial size (LA/RA ratio) remained stable in both groups and discriminated between PH-HFpEF and IPAH. In a second study, routine non-gated CTA was used to validate the diagnostic use of a LA/RA ratio in 95 consecutive treatment-naive patients with a final diagnosis of either IPAH (n=64) or PH-HFpEF (n=31). ROC analyses were conducted to determine the discriminative properties of atrial size parameters. On a transversal view, LA size was 19cm² (±5) in the IPAH group versus 27cm² (±6) in the PH-HFpEF group (p<0.001). CTA derived LA/RA ratio was significantly higher in PH-HFpEF patients compared to IPAH patients and had good discriminative abilities (AUC=0.833).

CONCLUSIONS

Assessing LA/RA size ratio by non-gated CTA allows for accurate discrimination between PH-HFpEF and IPAH patients. Because CTA is often available in the early diagnostic work-up, a LA/RA size ratio may guide clinical and diagnostic decision-making, even before invasive hemodynamic measurements.