Right Ventricle To Left Ventricle Research Articles

Deep Learning based Pulmonary Embolism Detection using Convolutional Feature Maps of CT Pulmonary Angiography Images

Pulmonary Embolism (PE) is a blood clot in the pulmonary arteries of the lungs. Currently, Computerized Tomography Pulmonary Angiography (CTPA) scans are used to diagnose this condition. However, to manually locate the presence of a PE in the scan is laborious. In this paper, the detection of PE and prediction of its features like location, Right Ventricle to Left Ventricle (RV/LV) ratio, and chronicity are automated. First, for the detection of the embolisms, image features from the RSNA Pulmonary Embolism CT (RSPECT) dataset - containing over 12,000 CTPA studies, are extracted by several pre-trained Convolutional Neural Networks (CNN) - AlexNet, Inception V3, ResNet-18, and ResNet-50. Then, various Machine Learning (ML) classifiers are trained on these features and their performances are compared. Second, for the prediction of labels, multi-label classification is performed by training these networks with Binary Cross Entropy Logits (BCE Logits) loss. The results showed that for the detection task, k-NN classifier trained on ResNet-50 features achieved the highest sensitivity of 0.98 with 1.7 false positives per scan and an AUROC score of 97.4%. This system also improved on the state-of-the-art sensitivity score by 0.0975 and AUROC score by 3.4%. For multi-label classification, ResNet-18 performed comparatively better with the best validation loss of 0.07 and weighted macro-average ROC AUC score of 0.61.

Urokinase versus Alteplase in Patients with Intermediate-High-Risk Pulmonary Embolism Treated with Ultrasound-Accelerated Endovascular Thrombolysis.

Ultrasound-accelerated thrombolysis (USAT) is a safe and effective treatment for patients with intermediate-high-risk pulmonary embolism (PE). In all studies investigating USAT in the setting of PE, the recombinant tissue-plasminogen activator (rt-PA) alteplase or actilyse was used. Currently, there is a shortage of alteplase (Alteplase, Boehringer Ingelheim) in Europe. It is unknown whether the efficacy of urokinase (UK) is comparable with alteplase for USAT in patients with PE. Patients with intermediate-high-risk PE undergoing USAT with urokinase and alteplase were included in this study. One-to-one nearest neighbour matching was performed to account for baseline differences. We identified one patient treated with USAT and UK (n = 9) for each patient treated with USAT and alteplase (n = 9). A total of 56 patients underwent USAT. The treatment was successful in all patients. The propensity score matched the identified nine pairs of patients. There were no statistically significant differences in the change in right ventricle-to-left ventricle (RV/LV) ratio (0.4 ± 0.3 versus 0.5 ± 0.4, p = 0.54), systolic pulmonary artery pressure (17.3 ± 8.0 versus 18.1 ± 8.1, p = 0.17), or improvement of RV function (5.8 ± 3.8 versus 5.1 ± 2.6, p = 1.0). The complication rates were comparable (11% in both groups, p = 0.55). There were no deaths in hospital or during 90 days in either group. In this case-matched comparison, the short-term clinical and echocardiographic outcomes showed comparable results between USAT-UK and USAT-rt-PA.

Continuous mechanical aspiration thrombectomy performs equally well in main versus branch pulmonary emboli: A subgroup analysis of the EXTRACT-PE trial.

The EXTRACT-PE trial evaluated the safety and performance of the Indigo Aspiration System (PenumbraInc.) with an 8F continuous mechanical aspiration thrombectomy system for the treatment of pulmonary embolism (PE). This subgroup analysis evaluates performance outcomes of patients with main pulmonary artery (PA) emboli versus discrete unilateral or bilateral PA emboli without main PA involvement. The EXTRACT-PE trial was a prospective, single-arm, multicenter trial that enrolled 119 patients with acute submassive PE. Emboli location was collected at the time of enrollment, CT obstruction was measured and assessed by a Core Lab, and patients were grouped on whether emboli involved the main PA (with or without branch vessels) or not (branch vessels alone). Procedural device time, changes in the right ventricle to left ventricle (RV/LV) ratio, and systolic PA pressure from pre-and posttreatment were compared between the two groups. Out of the 119 patients enrolled, 118 had core lab-assessed clot locations. Forty-five(38.1%) had emboli that involved the main PA and 73 (61.9%) had only branch emboli. No significant difference was observed between these groups for 30-day mortality, procedural device time, changes in RV/LV ratio, reduction in CT Obstruction Index, or for systolic PA pressure from pre-and posttreatment. The mean absolute reduction in clot burden was significant in both groups. Continuous mechanical aspiration thrombectomy with the 8F Indigo Aspiration System was effective at improving clinical outcomes for submassive PE patients regardless of emboli location, and clot burden was significantly reduced in both groups.

Pulmonary Vein Sign on Unenhanced-MRI as a Sign of Severe Pulmonary Embolism

Background: Increased right ventricle-to-left ventricle (RV/LV) ratio on computed tomography pulmonary angiography (CTPA) has been reported as a poor prognostic indicator in patients with acute pulmonary embolism (PE). It has also been reported that pulmonary vein sign (PVS) on CTPA is a rare finding of PE. Objectives: To evaluate PVS on CTPA and unenhanced magnetic resonance imaging (MRI) in patients with PE suspicion. We also aimed to investigate the relationship between the severity of PE and presence of PVS, RV/LV ratio and combination of these two on unenhanced MRI. Patients and Methods: One-hundred-twelve patients with PE suspicion who underwent CTPA and unenhanced-MRI [steady state free precession (SSFP)] within the first 48-hours constituted the study group. All CTPA images were evaluated for the presence, location and severity of PE by observer-1. Two observers (observer-2 and 3), independently evaluated unenhanced-MR images for the presence of PVS without knowing the results of CTPA. Then, these 2 observers reviewed the CTPA and MRI images together with observer-4 to reach the final consensus for the presence of PVS and measurement of RV/LV ratio. Cohen’s Kappa analysis was used to assess the agreement between observers. Relationship between the mean PE index and imaging findings (PVS, RV/LV) were calculated. Results: Presence of PVS on CT or MRI is significantly correlated with PE index and patients with PVS had more severe PE than those without. Presence of both PVS and RV/LV ratio > 1 on MRI indicates more severe pulmonary embolism than absence of PVS or RV/LV ratio > 1. There was a very good agreement for the detection of PVS between two observers on unenhanced MRI. Conclusion: PVS on CTPA or unenhanced MRI can be used as a sign of severe PE and it may also be an indicator of right heart dysfunction.

Role of hemogram parameters in diagnosis and assessing severity of pulmonary embolism

Introduction To investigate the changes in platelets indices in patients with pulmonary embolism (PE) and to examine the correlation of these parameters with the extent of vascular occlusion. Patients and methods The present study was conducted on 70 patients who were admitted because of clinical suspicion of PE. For all patients, complete history taking and examination, routine laboratory investigations, chest radiography, ECG, and transthoracic echocardiography were done. For patients with low and intermediate clinical probability, assessment of d-dimer level was done. For patients with high clinical probability and those with positive d-dimer finding, pulmonary computed tomography angiography was performed with measurement of pulmonary artery obstructive index (PAOI) and right ventricle to left ventricle (RV/LV) ratio. Results Fifty patients were confirmed to have PE and the remaining 20 patients were negative for PE. The group of patients without PE served as a control group. The differences in platelet count, mean platelet volume (MPV), platelet distribution width (PDW), red cell distribution width, and other parameters were compared between both the groups. MPV and PDW were significantly higher in patients with acute PE than in other patients (P=0.0002 and 0.0001). A significant correlation was found between MPV and both PAOI (P=0.049) and RV/LV ratio (P=0.0004). Moreover, significant correlation between PDW and PAOI (P=0.001) and between PDW and RV/LV (P=0.044) was found. The best cutoff value for MPV for the prediction of RV dysfunction was more than 9.4 fl (sensitivity 46.7%; specificity 94.7%). The best cutoff value for PDW for the prediction of RV dysfunction was more than 15.85 fl (sensitivity 75%; specificity 65.9%; P=0.006).

Abstract 334: Pulmonary Embolism Response Team: Implementation and Outcomes at Northshore University Healthsystems

Introduction: Pulmonary Embolism Response Team (PERT) protocols are used to expedite risk stratification and management of complex acute pulmonary embolisms (PE). The process varies by institution. Objective: To quantify mortality outcomes after implementing PERT at our practice (Figure 1). Methods: 58 patients in our PERT registry were analyzed for parameters seen on table 1. Quantitative data is presented as median and qualitative data as percentages. Results: Median age was 70.5, with female predominance 65.5% (38 out of 58), PE severity index (PESI) of 101.6, and cancer in 33% (19 out of 58) [Table 1]. 10%(6 out of 58) received thrombolysis and 14%(8 out of 58) received IVC filter. 5 deaths occurred of which 60% (3 patients) were due to cancer progression. Conclusion: Our PERT algorithm is anchored in right ventricle to left ventricle (RV/LV) ratio on CT reading and does successfully select high risk PE patients. Mortality is similar to that expected by PESI stratification. Prospective comparative evaluation of PERT is needed to see if it affects early mortality.

Prenatal Diagnosis of Fetal Interrupted Aortic Arch Type A by Two-Dimensional Echocardiography and Four-Dimensional Echocardiography with B-Flow Imaging and Spatiotemporal Image Correlation.

Fetal interrupted aortic arch (IAA) is a rare cardiac anomaly and its prenatal diagnosis is challenging. The purpose of our report is to evaluate the use of two-dimensional echocardiography (2DE) and 4D echocardiography with B-flow imaging and spatiotemporal image correlation (4D BF-STIC) in detecting IAA type A (IAA-A). Twenty-three cases of confirmed IAA-A identified by fetal echocardiography were involved in the study. The fetal echocardiography image data were reviewed to analyze the ratio of right ventricle to left ventricle (RV/LV) diameter, the ratio of main pulmonary artery to ascending aorta (MPA/AAO) diameter, and the correlation of RV/LV diameter ratio and size of ventricular septal defect (VSD). 4D BF-STIC was performed in 21 fetuses using the sagittal view (4D BF-STIC-sagittal) and the four-chamber view (4D BF-STIC-4CV) as initial planes of view. An additional 183 normal fetuses were also included in our study. RV/LV and MPA/AAO ratios were calculated and compared with that of IAA-A fetuses. Fetal 2DE, 4D BF-STIC-sagittal, and 4D BF-STIC-4CV were used to visualize the aortic arch and its associated neck vessels. Six subgroups were evaluated according to gestational age. Fetal 2DE, 4D BF-STIC-sagittal, and 4D BF-STIC-4CV made the correct prenatal diagnosis of IAA-A in 19/23 (82.6%), 14/21 (66.7%), and 19/21 (90.5%) of patients, respectively. A significantly enlarged MPA combined with symmetric ventricles was found in the IAA-A fetuses, while the size of the VSD was negatively correlated with RV/LV ratio. 4D BF-STIC-sagittal and 4D BF-STIC-4CV were better than traditional 2D ultrasound in detecting the aortic arch and neck vessels between 17 and 28 gestational weeks and 29 to 40 gestational weeks in normal fetuses. It is demonstrated that IAA-A could be diagnosed by traditional fetal echocardiography, while 4D technique could better display the anatomic structure and the spatial relationships of the great arteries. Use of volume reconstruction may promote its clinical usage and help prenatal diagnosis.

The effects and mechanism of ginsenoside Rg1 on myocardial remodeling in an animal model of chronic thromboembolic pulmonary hypertension

BackgroundRecent studies haveshown that ginsenoside Rg1, extracted from the dry roots of Panax notoginseng as a traditional Asian medicine, plays an anti-fibrosis role in myocardial remodeling. However, the mechanism still remains unclear. In the present study, we investigate the effect of ginsenoside Rg1on the collagenic remodeling of myocardium in chronic thromboembolic pulmonary hypertension (CTEPH), and its potential mechanism.MethodsA rat model of CTEPH was established by injecting thrombi through the jugular vein wice in2 weeks. Four weeks later, four groups (Group A: normal rats + normal saline; Group B: normal rats + Rg1; Group C: CTEPH model + normal saline; Group D: CTEPH model + Rg1) were established. Normal saline and Rg1 were administrated by intraperitoneal injection. Ineach group, we measured the hemodynamic parameters, as well as the right ventricle to left ventricle (RV/LV) thickness ratio. Myocardial tissue sections of the RV were stained by hematoxylin-eosin +gentian violet and the morphological characteristics were observed by light microscopy. The matrix metalloproteinases (MMP) -2 and −9 were detected by the western blot.ResultsCompared with Group A and Group B, the right ventricular systolic pressure was significantly increased in Group C and significantly decreased in Group D. Compared with Group A and Group B, the RV/LV thickness ratio of the rats was significantly higher in Group C and Group D. There was significant fibrosis with collagen in Group C compared with Group A and Group B, and less significant changes in Group D were observed compared with those in Group C. The expression of MMP-2 and MMP-9 exhibited a significant decrease in Group C and was also significantly decreased in Group D compared withGroup A and Group B. Also, a negative linear relationship was shown between collagen-I and the expression of MMP-2 and MMP-9.ConclusionsOur animal study showed that ginsenoside Rg1 positively affects myocardial remodeling and pulmonary hemodynamics in CTEPH. Upregulation of the expression of MMP-2 and MMP-9 could explain the beneficial effects of ginsenoside Rg1 in CTEPH.

Pulmonary embolectomy in high-risk acute pulmonary embolism: The effectiveness of a comprehensive therapeutic algorithm including extracorporeal life support

ObjectivesTo investigate the effectiveness of a comprehensive therapeutic algorithm including extracorporeal life support (ECLS) in high-risk acute pulmonary embolism (aPE) treated with pulmonary embolectomy. Materials and methodsThis retrospective study included 25 consecutive patients of aPE treated with pulmonary embolectomy in a single institution between June 2005 and July 2012. All patients had high-risk aPE identified by computed tomographic angiography and were not suitable for thrombolytic therapy. High-risk aPE here was defined as aPE with (1) hemodynamic instability, (2) a pulmonary artery obstruction index (PAOI)≥0.5, (3) a diameter ratio of right ventricle-to-left ventricle (RV-to-LV)≥1.0, or (4) right heart thrombi. Once the eligibility was confirmed, a 3-staged therapeutic algorithm was adopted to perform an aggressive preoperative resuscitation, an expeditious pulmonary embolectomy with multidisciplinary postoperative care, and a thorough surveillance for recurrence. ResultsAmong the 25 patients, 24 had a PAOI≥0.5 and 23 had a RV-to-LV diameter ratio≥1.0. Four patients had right heart thrombi. Sixteen patients developed preoperative instability requiring inotropic and/or mechanical support. Eight in the 16 had a preoperative cardiac arrest (CA) and six of these were bridged to surgery on ECLS. Three in the 6 patients weaned ECLS after surgery and survived to discharge. The overall in-hospital mortality was 20% (n=5). A preoperative CA (Odds ratio [OR]: 16, 95% confidence interval [CI]: 1.4–185.4, p=0.027, c-index: 0.80) and a postoperative requirement of ECLS (OR: 36, 95% CI: 2.1–501.3, p=0.008, c-index: 0.85) was the pre- and postoperative predictor of in-hospital mortality. No late deaths or re-admission for recurrence were found during a median follow-up of 19 months (interquartile range: 8–29). ConclusionPulmonary embolectomy was an effective intervention of high-risk aPE. However, the occurrence of preoperative CA still carried a high mortality in spite of the assistance of ECLS.

CT Findings and Long-Term Mortality After Pulmonary Embolism

The utility of CT findings in predicting long-term mortality in patients with acute pulmonary embolism (PE) is unknown. The purpose of this study is to retrospectively determine whether three CT findings--increased embolic burden, interventricular septal bowing toward the left ventricle, and right ventricle-to-left ventricle (RV/LV) diameter ratio greater than 1--are independent predictors of long-term all-cause mortality after acute PE. A total of 1105 patients (47% female; mean age, 63 ± 16 years) with CT scans positive for PE from January 1, 1997, to December 31, 2002, were included. Scans were independently interpreted by two observers, with a third independent observer reviewing discrepant cases. CT findings and clinical information were compared with all-cause mortality using univariate and multivariate logistic regression analyses. The median duration of survival was 6.2 years following acute PE, with estimated 10-year survival of 37.4%. CT-derived embolic burden was associated with a very small decrease in long-term all-cause mortality in both univariate (hazard ratio [HR], 0.97; p < 0.001) and multivariate (HR, 0.97; p < 0.001) analyses. Interventricular septal bowing and RV/LV diameter ratio were not significantly associated with long-term all-cause mortality. CT findings are not predictive of decreased long-term survival after acute PE.

Comparison of automated 4-chamber cardiac views versus axial views for measuring right ventricular enlargement in patients with suspected pulmonary embolism

Compare the right ventricle to left ventricle (RV/LV) diameter ratio obtained from axial pulmonary CT angiograms (CTPA) with those derived from automatically generated 4-chamber (4-CH) reformats in patients with suspected pulmonary embolism (PE). In this institutional review board-approved study we included 120 consecutive non ECG-gated CTPA from 3 institutions (mean age 60 ± 16 years; 71 women). Twenty 64-slice CTPA with PE and 20 without PE were selected per institution. For each patient the RV/LV diameter ratio was obtained from both axial CTPA images and automatically generated 4-CH reformats. Measurements were performed twice in two separated sessions by 2 experienced radiologists and 2 residents. The differences between the measurements on both views were evaluated. The 4-CH view was successfully obtained in 113 patients. The mean axial and 4-CH diameter ratios were comparable for three of the four readers (p = 0.56, p = 0.13, p = 0.08). Although the mean diameters (1.0 and 1.03 respectively) for one resident were significantly different (p = 0.013), the difference of 0.03 seems negligible in clinical routine. Three readers achieved equally high intra-reader agreements with both measurements (ICCs of 0.94, 0.95 and 0.96), while one reader showed a different variability with ICCs of 0.96 for the axial view and 0.91 for the 4-CH view. The inter-reader agreement was equally high for both measurement types with ICCs of 0.95 and 0.94, respectively. In patients with suspected PE, RV/LV diameters ratio can be measured with the same reproducibility and accuracy using an automatically generated 4-CH view compared to the axial view.

A Simple Clinical Model Composed of ECG, Shock Index, and Arterial Blood Gas Analysis for Predicting Severe Pulmonary Embolism

Objective diagnosis of severe pulmonary embolism (PE) is obligatory because of its considerable mortality. To assess the abilities of electrocardiography (ECG) score (sECG) and the newly generated scoring system composed of the scores obtained from arterial blood gas (ABG) analysis and shock index (SI) in addition to sECG in predicting severe PE. The degree of pulmonary vascular obstruction (sPVO) and the right ventricular dysfunction (RVD) were determined with spiral computed tomography (CT) in 53 consequent patients with PE. Twelve-lead ECG taken within a day of PE event and ABG values were evaluated according to ECG scoring system and original Geneva system, respectively. The mean age of patients was 62.6 ± 13.4 years. Right ventricular dysfunction, sPVO ≥ 50%, hypoxemia, and SI were present in 34 (64.2%), 27 (50.9%), 50 (94.3%), and 22 (41.5%) patients, respectively. The mean sECG, 5.9 ± 5.1, was correlated with sPVO, maximum diameter of right ventricle (RV), and right ventricle to left ventricle (RV/LV) ratio (r = .385, r = .415, and r = .329, respectively). The mean newly generated score was 10.9 ± 5.5 and correlated with sPVO, maximum diameter of RV, and RV/LV ratio (r = .394, r = .483, and r = .393, respectively). Receiver operator characteristic (ROC) curve analyses revealed that sECG ≥ 3.5, s (ECG + SI) ≥ 4.5, and s (ECG + SI + ABG) ≥ 9.5 predict the severe PE patients with 70.6%, 61.8%, 58.8% sensitivities and 52.6%, 63.2%, 73.7% specificities, respectively. Adding the scores obtained from SI and ABG to the sECG enhances the specificity of sECG in predicting RVD (+) or severe PE patients, although a lesser degree decreasing in sensitivity may occur.

Computed Tomographic Angiography in Acute Pulmonary Embolism

To compare the indices of right ventricular dysfunction (RVD) obtained from axial transverse images with those derived from the reconstructed 4-chamber and short-axis views in patients with acute pulmonary embolism (PE). Eighty-eight patients with acute PE were retrospectively enrolled. For each patient, axial transverse images and reconstructed 4-chamber and short-axis views were reviewed. Measurements of the ratios of right ventricle to left ventricle (RV/LV) diameters and RV/LV areas were then obtained from all series. Values derived from each method were compared and correlated to arterial obstruction index. In the studied cohort, RV/LV diameters and RV/LV areas obtained from axial transverse images and the reconstructed 4-chamber views were not statistically different. In contrast, a statistically significant difference was observed between the values of RV/LV areas derived from both axial transverse and 4-chamber views and those obtained from short-axis views (P < 0.0001). There was a weak to moderate correlation between both RV/LV diameters and RV/LV areas and the computed tomographic obstruction index. However, when the study cohort was divided into 3 subgroups with an arterial obstruction index of less than 15% (n = 26), 15% to 30% (n = 21), and greater than 30% (n = 41), those who had values greater than 30% revealed the highest correlation with the indices of RVD. In patients with acute PE, the indices of RVD derived from axial transverse images and the reconstructed 4-chamber views yield comparative values. Given the simplicity of the former analysis, it should be taken into consideration for risk stratification in acute PE.

First-pass angiography in mice using FDG-PET: a simple method of deriving the cardiovascular transit time without the need of region-of-interest drawing

In this study, we developed a simple and robust semi-automatic method to measure the right ventricle to left ventricle (RV-to-LV) transit time (TT) in mice using 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). The accuracy of the method was first evaluated using a 4-D digital dynamic mouse phantom. The RV-to-LV TTs of twenty-nine mouse studies were measured using the new method and compared to those obtained from the conventional ROI-drawing method. The results showed that the new method correctly separated different structures (e.g., RV, lung, and LV) in the PET images and generated corresponding time activity curve (TAC) of each structure. The RV-to-LV TTs obtained from the new method and ROI method were not statistically different (P = 0.20; r = 0.76). We expect that this fast and robust method is applicable to the pathophysiology of cardiovascular diseases using small animal models such as rats and mice.

Endothelin-A Receptor Blockade Prevents and Partially Reverses Neonatal Hypoxic Pulmonary Vascular Remodeling

Hypoxia-induced pulmonary vascular remodeling (HPVR) may lead to persistent pulmonary hypertension of the newborn or cor pulmonale. Endothelin-1 (ET-1), via endothelin-A (ET(A)) receptor activation, mediates hypoxic pulmonary vasoconstriction. Our objectives were to develop a newborn mouse model of HPVR and to test the hypothesis that ET(A) blockade would prevent and reverse HPVR in this model. C57BL/6 mice (n = 64) were exposed to 12% oxygen (HYP group) or room air (RA group) from birth to 2 wk of age. The mice were injected intraperitoneally daily with either BQ-610 (ET(A) blocker) or vehicle (cottonseed oil) from birth (prevention study) or from 6 d of age (reversal study). HPVR was assessed histologically by pulmonary vascular morphometry by an examiner masked to study group, and by measurement of the right ventricle to left ventricle (RV/LV) thickness ratio. Hypoxia increased medial wall thickness (%WT) in pulmonary arteries <100 mum in diameter and RV/LV thickness ratio. BQ-610 prevented the hypoxia-induced increase in %WT and RV/LV thickness ratio when given from birth, and later therapy partially reversed the hypoxia-induced increase in %WT but not RV/LV thickness ratio. These data show that in the newborn mouse model, chronic hypoxia leads to HPVR that can be completely prevented and partially reversed by ET(A) blockade. These results indicate that ET-1, acting via ET(A) receptors, is a mechanism of pathophysiologic significance underlying neonatal HPVR. Development of this newborn mouse model of HPVR facilitates investigation of mechanisms underlying this important and severe disease entity in human infants.