From Acute to Chronic Thromboembolic Disease

Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Disease: Success Rate and Complications among Different Patient Populations

INTRODUCTION

Balloon pulmonary angioplasty (BPA) is an effective intervention for patients with chronic thromboembolic pulmonary disease (CTEPD). We aimed to identify the patient group with a low success rate or high complication rate of BPA, which is still unclear.

METHODS

Both CTEPD patients with or without pulmonary hypertension (CTEPH and NoPH-CTEPD) were included. CTEPH patients were divided into groups with or without pulmonary endarterectomy (PEA-CTEPH and NoPEA-CTEPH). The efficacy and safety of BPA were compared among the groups.

RESULTS

There were 450, 66, and 41 sessions in the NoPEA-CTEPH, PEA-CTEPH, and NoPH-CTEPD groups, respectively. The success rate (≥1 degree improvement in flow grade) in the PEA-CTEPH group was 94.5%, significantly lower than that in the NoPEA-CTEPH (97.1%) and NoPH-CTEPD (98.4%) groups (p = 0.014). The percentage of complete flow recovery in treated vessels was also lower in PEA-CTEPH group. BPA-related complication rate in NoPEA-CTEPH, PEA-CTEPH, and NoPH-CTEPD patients was 6.1%, 6.0%, and 0.0%, respectively (p = 0.309). One BPA-related death occurred (solely in NoPEA-CTEPH). Mean pulmonary artery pressure ≥41.5 mm Hg was a predictor of BPA-related complications. NoPEA-CTEPH patients had more improvement in 6-min walk distance (6MWD, 87 ± 93 m NoPEA-CTEPH vs. 40 ± 43 m PEA-CTEPH vs. 18 ± 20 m NoPH-CTEPD, p = 0.012).

CONCLUSIONS

BPA was safe and effective for all CTEPD groups with less improvement for the PEA-CTEPH and NoPH-CTEPD groups. The success rate of BPA was lower in the PEA-CTEPH group and the complication rate was lower in the NoPH-CTEPD group. Pre-BPA treatment to lower pulmonary artery pressure should not be overlooked in CTEPD patients.

Integrating Pharmacomechanical Treatments for Pulmonary Embolism Management within a Hub-and-Spoke System in the Swiss Ticino Region

The Swiss Ticino regional pulmonary embolism response team (PERT) features direct access to various pharmacomechanical PE management options within a hub/spoke system, by integrating evidence, guidelines' recommendations and personal experiences. This system involves a collaborative management of patients among the hospitals distributed throughout the region, which refer selected intermediate-high or high PE patients to a second-level hub center, located in Lugano at Cardiocentro Ticino, belonging to the Ente Ospedaliero Cantonale (EOC). The hub provides 24/7 catheterization laboratory activation for catheter-based intervention (CBI), surgical embolectomy and/or a mechanical support system such as extracorporeal membrane oxygenation (ECMO). The hub hosts PE patients after percutaneous or surgical intervention in two intensive care units, one specialized in cardiovascular anesthesiology, to be preferred for patients without relevant comorbidities or with hemodynamic instability and one specialized in post-surgical care, to be preferred for PE patients after trauma or surgery or with relevant comorbidities, such as cancer. From April 2022 to December 2023, a total of 65 patients were referred to the hub for CBI, including ultrasound-assisted catheter-directed thrombolysis (USAT) or large-bore aspiration intervention. No patient received ECMO or underwent surgical embolectomy.

Cardiopulmonary exercise test to detect cardiac dysfunction from pulmonary vascular disease

BACKGROUND

Cardiac dysfunction from pulmonary vascular disease causes characteristic findings on cardiopulmonary exercise testing (CPET). We tested the accuracy of CPET for detecting inadequate stroke volume (SV) augmentation during exercise, a pivotal manifestation of cardiac limitation in patients with pulmonary vascular disease.

METHODS

We reviewed patients with suspected pulmonary vascular disease in whom CPET and right heart catheterization (RHC) measurements were taken at rest and at anaerobic threshold (AT). We correlated CPET-determined O2·pulseAT/O2·pulserest with RHC-determined SVAT/SVrest. We evaluated the sensitivity and specificity of O2·pulseAT/O2·pulserest to detect SVAT/SVrest below the lower limit of normal (LLN). For comparison, we performed similar analyses comparing echocardiographically-measured peak tricuspid regurgitant velocity (TRVpeak) with SVAT/SVrest.

RESULTS

From July 2018 through February 2023, 83 simultaneous RHC and CPET were performed. Thirty-six studies measured O2·pulse and SV at rest and at AT. O2·pulseAT/O2·pulserest correlated highly with SVAT/SVrest (r = 0.72, 95% CI 0.52, 0.85; p < 0.0001), whereas TRVpeak did not (r = -0.09, 95% CI -0.47, 0.33; p = 0.69). The AUROC to detect SVAT/SVrest below the LLN was significantly higher for O2·pulseAT/O2·pulserest (0.92, SE 0.04; p = 0.0002) than for TRVpeak (0.69, SE 0.10; p = 0.12). O2·pulseAT/O2·pulserest of less than 2.6 was 92.6% sensitive (95% CI 76.6%, 98.7%) and 66.7% specific (95% CI 35.2%, 87.9%) for deficient SVAT/SVrest.

CONCLUSIONS

CPET detected deficient SV augmentation more accurately than echocardiography. CPET-determined O2·pulseAT/O2·pulserest may have a prominent role for noninvasive screening of patients at risk for pulmonary vascular disease, such as patients with persistent dyspnea after pulmonary embolism.

Value of exercise right heart catheterization in the differential diagnosis of chronic thromboembolic pulmonary disease

INTRODUCTION AND OBJECTIVES

Chronic thromboembolic disease refers to the presence of chronic thrombotic pulmonary vascular thrombosis without pulmonary hypertension (PH) at rest but with exercise limitation after pulmonary embolism (PE). Our aim was to evaluate the hemodynamic response to exercise in these patients and its correlation with the values reached in cardiopulmonary exercise testing.

METHODS

We included symptomatic patients with persistent pulmonary thrombosis after PE. We excluded patients with left heart disease or significant PH (mean pulmonary arterial pressure [mPAP] >25mmHg, pulmonary vascular resistance >3 WU, and pulmonary capillary wedge pressure [PCWP] >15mmHg). Cardiopulmonary exercise testing and exercise right heart catheterization were performed. Exercise-induced precapillary PH was defined as mPAP/CO slope >3 and PCWP/CO slope <2mmHg/l/min. The hemodynamic response and the values obtained in cardiopulmonary exercise testing were compared between patients with and without exercise-induced precapillary PH.

RESULTS

We studied 36 patients; 4 were excluded due to incomplete hemodynamic data. Out of the 32 patients analyzed; 3 developed a pathological increase in PCWP. Among the remaining 29 patients (mean age, 49.4±13.7 years, 34.5% women), 13 showed exercise-induced PH. Resting mPAP was higher in those who developed exercise-induced PH (23.3±5.4 vs 19.0±3.8mmHg; P=.012), although CO was similar in the 2 groups. Patients with exercise-induced PH exhibited data of ventilatory inefficiency with reduced values of end-tidal CO2 pressure at the anaerobic threshold (32.8±3.0 vs 36.2±3.3mmHg; P=.021) and a higher Ve/VCO2 slope (34.2±4.8 vs 30.7±5.0; P=.049).

CONCLUSIONS

Exercise limitation and ventilatory inefficiency could be attributable to exercise-induced precapillary PH in a subgroup of patients with persistent pulmonary thrombosis and dyspnea.

Chronic Thromboembolic Pulmonary Hypertension: A Review of the Multifaceted Pathobiology

Chronic thromboembolic pulmonary disease results from the incomplete resolution of thrombi, leading to fibrotic obstructions. These vascular obstructions and additional microvasculopathy may lead to chronic thromboembolic pulmonary hypertension (CTEPH) with increased pulmonary arterial pressure and pulmonary vascular resistance, which, if left untreated, can lead to right heart failure and death. The pathobiology of CTEPH has been challenging to unravel due to its rarity, possible interference of results with anticoagulation, difficulty in selecting the most relevant study time point in relation to presentation with acute pulmonary embolism (PE), and lack of animal models. In this article, we review the most relevant multifaceted cross-talking pathogenic mechanisms and advances in understanding the pathobiology in CTEPH, as well as its challenges and future direction. There appears to be a genetic background affecting the relevant pathological pathways. This includes genetic associations with dysfibrinogenemia resulting in fibrinolysis resistance, defective angiogenesis affecting thrombus resolution, and inflammatory mediators driving chronic inflammation in CTEPH. However, these are not necessarily specific to CTEPH and some of the pathways are also described in acute PE or deep vein thrombosis. In addition, there is a complex interplay between angiogenic and inflammatory mediators driving thrombus non-resolution, endothelial dysfunction, and vascular remodeling. Furthermore, there are data to suggest that infection, the microbiome, circulating microparticles, and the plasma metabolome are contributing to the pathobiology of CTEPH.

Predictors of chronic thromboembolic pulmonary hypertension in patients with submassive pulmonary embolism treated with catheter-directed thrombolysis versus anticoagulation alone: A secondary analysis of the SUNSET sPE trial

OBJECTIVE

Chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism (PE) is a morbid complication with suboptimal treatment. We aimed to evaluate the biomarker profile and functional outcomes in patients with submassive PE (sPE) treated with catheter-directed thrombolysis (CDT) compared with anticoagulation alone (ACA). We performed a secondary biomarker and survey analysis of the SUNSET sPE (standard vs ultrasound-assisted catheter thrombolysis for submassive pulmonary embolism) randomized trial comparing standard CDT to ultrasound-assisted thrombolysis in patients with sPE.

METHODS

As a part of the SUNSET sPE study, patients who did not receive an intervention were enrolled in the medical (ACA) arm. The biomarkers associated with CTEPH in the literature (ie, CCL2, CXCL10, PTX3, GDF-15, RAGE, BCA-1, TFPI) were collected and measured using a multiplex assay at diagnosis, discharge, and 3-month follow-up. Patients underwent a 6-minute walk test and answered quality-of-life questionnaires (pulmonary embolism quality of life; University of California, San Diego, shortness of breath questionnaire; 36-item short-form survey) at 3 months after diagnosis. Comparisons were made using the Student t test. Nonparametric tests were used when the distributions were not normal. Significance was set at P ≤ .05.

RESULTS

A total of 72 patients (age, 56 ± 15 years; 40.3% women) were included in the present analysis. Of these 72 patients, 53 underwent CDT and 19 were included in the ACA arm. The baseline right ventricle/left ventricle ratios were similar between the two groups (CST, 1.8; ACA, 1.7). The survival and complication rates were similar between the two groups. At discharge, CXCL10 (768.9 ± 148.6 pg/mL vs 3032.0 ± 1201.0 pg/mL; P = .018) and PTX3 (3203.5 ± 1298.0 pg/mL vs 12,716.2 ± 6961.5 pg/mL; P = .029) were lower in the CDT group and displayed a quicker return to baseline than in the ACA group. This trend, although not significant, was also seen with the other biomarkers. At 3 months, the 6-minute walking distance and quality-of-life scores were similar between both groups.

CONCLUSIONS

In patients with sPE, the biomarkers of CTEPH were lower with CDT compared with ACA. At 3 months, both groups demonstrated similar biomarker levels, 6-minute walking distances, and quality-of-life scores.

Interventional therapies in acute pulmonary embolus-current trends and future directions

Venous thromboembolic disease presenting with acute pulmonary embolus (PE) can be treated in a variety of ways from anticoagulation as an outpatient to surgical embolectomy with many new interventional therapies being developed. Mortality in these patients can be as high as 50% and many of these treatments are also considered to be high risk. Early involvement of a multidisciplinary team and patient risk stratification can aid management decisions in these complex patients who can suddenly deteriorate.In this review, we summarise the evidence behind new and developing interventional therapies in the treatment of high and intermediate-high risk PE including catheter-directed thrombolysis, pharmacomechanical thrombolysis, thromboaspiration and the growing role of extracorporeal membrane oxygenation in the stabilisation and management of this cohort of patients.

Comparison of Medical Treatment Efficiency With Shear Wave Elastography Values of Thrombus in Patients With Lower Extremity Deep Vein Thrombosis

ABSTRACT

In lower-extremity deep vein thrombosis (DVT), thrombus age is essential for successful treatment. The aim of our study was to compare the shear wave elastography (SWE) values measured before treatment and achieved lumen patency after treatment in lower-extremity DVT patients with total occlusion. Patients diagnosed with DVT in the acute-subacute stage (<4 week) with total thrombosis in lower extremity were included in this prospective study. Shear wave elastography measurements were performed where the thrombus was most prominent and homogeneous. To evaluate patient response to treatment, lumen patency (partial [>25%] or total recanalization) was examined using color Doppler imaging in the first and third months posttreatment. Shear wave elastography values with and without patency were compared using an independent t test. Among 75 patients in this study, at the first-month color Doppler imaging examination, the SWE values were 1.77 ± 0.49 (1.09-3.03) m/s in patients who achieved lumen patency (n = 42) and 2.21 ± 0.54 (1.24-3.36) m/s in those who did not show lumen patency (n = 33). The difference between the groups' mean elastography value was statistically significant ( P < 0.001). At the third-month examination, the SWE values were 1.76 ± 0.46 (1.09-3.03) m/s in patients with lumen patency (n = 55) and 2.52 ± 0.48 (1.74-3.36) in patients without lumen patency (n = 20). The difference between the 2 groups' mean elastography value was statistically significant ( P < 0.001). We concluded that it is more difficult to achieve lumen patency in veins occluded by thrombus with higher elasto values, and endovascular interventional procedures should be considered during the initial treatment of high SWE value thrombosis.

Chronic thromboembolic pulmonary hypertension and the post-pulmonary embolism (PE) syndrome

Over a third of patients surviving acute pulmonary embolism (PE) will experience long-term cardiopulmonary limitations. Persistent thrombi, impaired gas exchange, and altered hemodynamics account for aspects of the postpulmonary embolism syndrome that spans mild functional limitations to debilitating chronic thromboembolic pulmonary hypertension (CTEPH), the most worrisome long-term consequence. Though pulmonary endarterectomy is potentially curative for the latter, less is understood surrounding chronic thromboembolic disease (CTED) and post-PE dyspnea. Advances in pulmonary vasodilator therapies and growing expertise in balloon pulmonary angioplasty provide options for a large group of patients ineligible for surgery, or those with persistent postoperative pulmonary hypertension. In this clinical review, we discuss epidemiology and pathophysiology as well as advances in diagnostics and therapeutics surrounding the spectrum of disease that may follow months after acute PE.

Residual pulmonary vascular obstruction and recurrence after acute pulmonary embolism: a systematic review and meta-analysis of individual participant data

We aimed to assess the relationship between residual pulmonary vascular obstruction (RPVO) on planar lung scan after completion of at least 3 months of anticoagulant therapy for acute pulmonary embolism (PE) and the risk of recurrent venous thromboembolism (VTE) or death due to PE one year after treatment discontinuation. The systematic review was registered with the International Prospective Registry of Systematic Reviews (PROSPERO: CRD42017081080). The primary outcome measure was to generate a pooled estimate of the rate of recurrent VTE at one year in patient with RPVO diagnosed on planar lung scan after discontinuation of at least 3 months of anticoagulant treatment for an acute PE. Individual data were obtained for 809 patients. RPVO (ie, obstruction >0%) was found in 407 patients (50.3%) after a median of 6.6 months of anticoagulant therapy for a first acute PE. Recurrent VTE or death due to PE occurred in 114 patients (14.1%), for an annual risk of 6.4% (95% confidence interval, 4.7%-8.6%). Out of the 114 recurrent events, 63 occurred within one year after discontinuation of anticoagulant therapy corresponding to a risk of 8.1% (6.4%-9.8%) at 1 year. The risk of recurrent VTE at one year was 5.8% (4.4-7.2) in participants with RPVO <5%, vs 11.7% (9.5-13.8) in participants with RPVO ≥5%. RPVO is a significant predictor of the risk of recurrent venous thromboembolism. However, the risk of recurrent events remains too high in patients without residual perfusion defect for it to be used as a stand-alone test to decide on anticoagulation discontinuation.

The value of ventilation/perfusion scanning and CT pulmonary angiography in predicting chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: a one-year follow-up study

To investigate the value of ventilation/perfusion (V/Q) scanning and CT pulmonary angiography (PA) in predicting CTEPH development after acute pulmonary embolism (APE). This study was performed in APE patients who had undergone both V/Q and CT PA after 3-month anticoagulation. The residual pulmonary obstructions were assessed based on V/Q and CT PA, and then recorded as pulmonary perfusion detect score (PPDs) and CT pulmonary artery obstruction index (PAOI). The predictive performance of PPDs and CT PAOI for CTEPH were determined and risk factors for predicting CTEPH development were identified. A total of 235 patients with initial diagnosis of APE were included in this study. ROC analysis showed that the AUCs of the PPDs and CT PAOI were 0.957 and 0.895, with corresponding cut-off values of 20.50% and 17.50% for predicting CTEPH development. Neither sensitivity nor specificity differed significantly between PPDs and CT PAOI (Sensitivity: 92.00% vs. 80.00%, P = 0.25; Specificity: 88.10% vs. 89.52%, P = 0.69). The univariable and multivariable logistic regression analysis demonstrated that pulmonary arterial hypertension confirmed by echocardiography at initial APE diagnosis (OR: 6.16, 95%CI: 1.31-29.02, P = 0.02), a PPDs of > 20.50% (OR: 22.95, 95%CI: 2.37-222.19, P = 0.007), and a CT PAOI of > 17.50% (OR: 9.98, 95%CI: 2.06-48.49, P = 0.004) were associated with CTEPH development. Both V/Q and CT PA after 3-month anticoagulation for APE showed great performance in predicting CTEPH development, and V/Q scanning has a tendency to be more sensitive but less specific than CT PA. The residual pulmonary embolism detected by V/Q and CT PA was associated with an increased risk of CTEPH development.

Modulation of soluble guanylate cyclase ameliorates pulmonary hypertension in a rat model of chronic thromboembolic pulmonary hypertension by stimulating angiogenesis

Acute pulmonary embolism (PE) does not always resolve after treatment and can progress to chronic thromboembolic disease (CTED) or the more severe chronic thromboembolic pulmonary hypertension (CTEPH). The mechanisms surrounding the likelihood of PE resolution or progress to CTED/CTEPH remain largely unknown. We have developed a rat model of CTEPH that closely resembles the human disease in terms of hemodynamics and cardiac manifestations. Embolization of rats with polystyrene microspheres followed by suppression of angiogenesis with the inhibitor of vascular endothelial growth factor receptor 2 (VEGF-R2) SU5416 results in transient, acute pulmonary hypertension that progresses into chronic PE with PH with sustained right ventricular systolic pressures exceeding 70 mmHg (chronic pulmonary embolism [CPE] model). This model is similar to the widely utilized hypoxia/SU5416 model with the exception that the "first hit" is PE. Rats with CPE have impaired right heart function characterized by reduced VO2 Max, reduced cardiac output, and increased Fulton index. None of these metrics are adversely affected by PE alone. Contrast-mediated CT imaging of lungs from rats with PE minus SU5416 show large increases in pulmonary vascular volume, presumably due to an angiogenic response to acute PE/PH. Co-treatment with SU5416 suppresses angiogenesis and produces the CTEPH-like phenotype. We report here that treatment of CPE rats with agonists for soluble guanylate cyclase, a source of cGMP which is in turn a signal for angiogenesis, markedly increases angiogenesis in lungs, and ameliorates the cardiac deficiencies in the CPE model. These results have implications for future development of therapies for human CTEPH.

Efficacy and safety of a 12-week outpatient pulmonary rehabilitation program in Post-PE Syndrome

BACKGROUND

The Post-Pulmonary Embolism Syndrome (PPES) comprises heterogeneous entities, including chronic thromboembolic disease with/without pulmonary hypertension (CTEPH/CTEPD), and deconditioning.

OBJECTIVES

To assess underlying physiological determinants of PPES, and efficacy and safety of rehabilitation training in these patients.

METHODS

56 consecutive PE patients with persistent dyspnea and/or functional limitations despite ≥3 months of anticoagulation underwent standardized diagnostic work-up including exercise testing as part of routine practice. All diagnostic (imaging and cardiopulmonary function) tests were interpreted by a core group of experienced clinicians. A subgroup of patients without CTEPH or other treatable conditions was referred for a 12-week personalized rehabilitation program, studying changes in physical condition and patient-reported outcome measures.

RESULTS

Persistent vascular occlusions were observed in 21/56 patients (38%) and CTEPH was confirmed in ten (18%). Regarding those without CTEPH, impaired cardiopulmonary responses were evident in 18/39 patients with available CPET data (46%), unrelated to chronic thrombi. Rehabilitation was completed by 27 patients after excluding 29 (patients with CTEPH or treatable comorbidities, refusal, ineligibility, or training elsewhere). Training intensity, PE-specific quality of life (PEmb-QoL) and fatigue (CIS) improved with a median difference of 20 W (p = 0.001), 3.9 points (p < 0.001) and 16 points (p = 0.003), respectively. Functional status (Post-VTE Functional Status Scale) improved ≥1 grade in 18 (67%) patients, and declined in one (3.7%).

CONCLUSIONS

Our findings suggest that abnormal cardiopulmonary responses to exercise are common in patients with PPES and are not limited to those with chronic thrombi. Offering pulmonary rehabilitation to patients not treated otherwise seems safe and promising.

Correlation Between Perfusion Abnormalities Extent in Ventilation/Perfusion SPECT/CT with Hemodynamic Parameters in Patients with Chronic Thromboembolic Pulmonary Hypertension

Objectives

Chronic thromboembolic pulmonary hypertension (CTEPH) is a type of pulmonary hypertension with persistent pulmonary vascular obstruction and exercise intolerance, which may benefit from pulmonary endarterectomy (PEA). Ventilation/perfusion (V/Q) scan is the preferred screening test of CTEPH, which can be used to assess the anatomical extent of the disease. This study aimed to analyze the correlation between the extent of mismatched Q defects in V/Q single photon emission computed tomography/computed tomography (SPECT/CT) with preoperative clinical and hemodynamic parameters in patients with CTEPH.

Methods

A total of 102 patients with CTEPH prior to PEA having V/Q SPECT/CT scans were retrospectively reviewed. Age, gender, New York Heart Association classification, intraoperative right-sided heart catheterization (mPAP and PVR), and 6-minute walk test (6MWT) findings were obtained from clinical records of patients.

Results

Linear regression analysis showed a significant but weak correlation between the preoperative mPAP and PVR with the extent of mismatched Q defects in V/Q SPECT/CT (rs=0.09474 with p=0.0016 and rs=0.045 with p=0.045, respectively). No significant correlation was found between 6MWT and extent of mismatched Q defects in V/Q SPECT/CT (p>0.05).

Conclusion

A quantitative assessment of Q defects on V/Q SPECT/CT might provide information about hemodynamic parameters in patients with CTEPH.

Perfusion Scintigraphy in Diagnosis and Management of Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening complication of acute pulmonary embolism (PE). Because the treatment of CTEPH is markedly different from that of other types of pulmonary hypertension, lung ventilation-perfusion (V/Q) scintigraphy is recommended for the workup of patients with unexplained pulmonary hypertension. Lung V/Q scintigraphy is superior to CT pulmonary angiography for detecting CTEPH. Perfusion defect findings of CTEPH can be different from those of acute PE. Familiarity with the patterns of perfusion defects seen during the initial workup of CTEPH and the expected posttreatment changes seen at follow-up imaging is essential for accurate interpretation of V/Q scintigraphy findings. ^©RSNA, 2019.

Pulmonary endarterectomy for patients with chronic thromboembolic disease

Objective:

Chronic thromboembolic disease (CTED) is characterized by persistent pulmonary thromboembolic occlusions without pulmonary hypertension. Early surgical treatment by performing pulmonary endarterectomy (PEA) may improve symptoms. The goal of the study was to review our experience and early outcome of PEA in patients with CTED.

Methods:

Data were prospectively collected on all patients who underwent PEA between 2011 and 2015. Patients with CTED and a mean pulmonary artery pressure (mPAP) of <25 mm Hg were identified. All patients were in New York Heart Association (NYHA) functional class II or III. Measured outcomes were in-hospital complications, improvement in cardiac function and exercise capacity, and survival after PEA. Patients were reassessed at 6 months following surgery.

Results:

A total of 23 patients underwent surgery. There was no in-hospital mortality, but complications occurred in six patients (26%). At 6 months following surgery, 93% of the patients remained alive. Following PEA, the mPAP fell significantly from 21.0±2.7 mm Hg to 18.2±5.5 mm Hg (p<.001). Pulmonary vascular resistance also significantly decreased from 2.2±0.7 wood to 1.5±0.5 wood (p<.001). The 6-min walking distance significantly increased from 322.6±80.4 m to 379.9±68.2 m (p<.001). There was a significant symptomatic improvement in all survivors in NYHA functional classes I or II at 6 months following surgery (p=.001).

Conclusion:

PEA in selected patients with CTED resulted in significant improvement in symptoms. The selection of patients for undergoing PEA in the absence of pulmonary hypertension must be made based on patients’ expectations and their acceptance of the perioperative risk.

Value of 18F-FDG PET/CT in differentiating malignancy of pulmonary artery from pulmonary thromboembolism: a cohort study and literature review

To determine the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiating malignancy of pulmonary artery (PA) from pulmonary thromboembolism (PTE) based on a larger number of cases by pooling our cases and those from the literature. Consecutive patients with a PA lesion who had undergone ¹⁸F-FDG PET/CT in our hospital were retrospectively reviewed. Moreover, PubMed, Embase, and Medline were searched for literature reporting individual maximum standardised uptake value (SUV_max) of the malignant PA lesion and/or PTE. ¹⁸F-FDG activity was compared between PA malignancy and PTE by pooling the data from literature and our patients. Receiver operating characteristic curve analysis was performed to determine the ability of SUV_max to differentiate PA malignancy from PTE. From our database, we identified 11 patients with pulmonary artery sarcoma (PAS), and nine cases of PTE. Fifty patients with a malignant PA lesion (40 cases of PAS and 10 cases of tumor embolism) and 22 subjects with PTE were extracted from the literature. In our cases, the SUV_max of PAS (11.1 ± 4.9, range: 5.5-19.9) was significantly higher than that of PTE (1.9 ± 0.6, range: 1.1-3.2; P < 0.001). There was no significant difference in the SUV_max between the literature data and our cases in malignant lesions or in PTE. Based on the pooled analysis of the literature data and our cases (61 cases of malignant lesions and 31 cases of PTE), the area under the curve for SUV_max to differentiate PA malignancy from PTE was 0.996 (95% CI: 0.989-1.000). At a cutoff value of 3.3, the sensitivity, specificity, and accuracy were 98.4%, 96.8%, and 97.8%, respectively. The ¹⁸F-FDG uptake value is an accurate index for determining PA malignancy.

Fibrinogen and the prediction of residual obstruction manifested after pulmonary embolism treatment

Residual pulmonary vascular obstruction (RPVO) and chronic thromboembolic pulmonary hypertension (CTEPH) are both long-term complications of acute pulmonary embolism, but it is unknown whether RPVO can be predicted by variants of fibrinogen associated with CTEPH.We used the Akaike information criterion to select the best predictive models for RPVO in two prospectively followed cohorts of acute pulmonary embolism patients, using as candidate variables the extent of the initial obstruction, clinical characteristics and fibrinogen-related data. We measured the selected models' goodness of fit by analysis of deviance and compared models using the Chi-squared test.RPVO occurred in 29 (28.4%) out of 102 subjects in the first cohort and 46 (25.3%) out of 182 subjects in the second. The best-fit predictive model derived in the first cohort (p=0.0002) and validated in the second cohort (p=0.0005) implicated fibrinogen Bβ-chain monosialylation in the development of RPVO. When the derivation procedure excluded clinical characteristics, fibrinogen Bβ-chain monosialylation remained a predictor of RPVO in the best-fit predictive model (p=0.00003). Excluding fibrinogen characteristics worsened the predictive model (p=0.03).Fibrinogen Bβ-chain monosialylation, a common structural attribute of fibrin, helped predict RPVO after acute pulmonary embolism. Fibrin structure may contribute to the risk of developing RPVO.

Chronic Thromboembolic Pulmonary Hypertension. The Journey from a Curiosity to a Cure

Chronic thromboembolic pulmonary hypertension is a progressive and life-threatening condition that is believed to be related to inadequate dissolution of acute pulmonary thromboemboli, followed by fibrotic organization. Without appropriate treatment, progressive pulmonary hypertension, right ventricular failure, and death may occur. While the disorder was initially described nearly a century ago in autopsy studies, antemortem diagnosis became feasible with the advent of cardiac catheterization and angiography techniques in the 1940s, while surgical thromboendarterectomy was not attempted until the 1960s. However, this procedure initially had high mortality rates until refinements in management and surgical techniques resulted in much improved outcomes starting in the 1980s. Many questions remain about the pathophysiology and epidemiology of this condition, with unclear contributions of genetics and environmental exposures. The optimal approach to diagnosis also continues to evolve, with improvements in preoperative imaging and hemodynamic assessment. Treatment of chronic thromboembolic pulmonary hypertension has not remained static, as surgical techniques continue to improve and newer pharmacological treatments and percutaneous catheter-based interventions may play therapeutic roles in selected patients. This is the introductory article of a series that provides a state-of-the-art review of chronic thromboembolic pulmonary hypertension.

Can thrombus age guide thrombolytic therapy?

Venous thrombosis (VT) is a common yet complex clinical condition that has shown minimal alteration in clinical management for decades. It is well known that thrombus evolves structurally over time, with complex changes resulting from the interplay between coagulation factors, cytokines, leukocytes and a myriad of other factors. Our current treatment options are most effective in the acute thrombus, which is composed predominantly of a loose mesh of fibrin and red blood cells (RBCs), making current anticoagulation therapies and thrombolytics quite effective in treatment. Later stages of thrombus are more cellular containing leukocytes, and develop a fibrotic collagenous framework that is more resistant to our current treatments. Understanding the biology of an evolving thrombus will allow us to tailor our treatment and optimize outcomes, as well as focus on novel therapies for the treatment of chronic thrombus. Given the morbidity and mortality of both post thrombotic syndrome (PTS) in patients with deep VT, as well as chronic thromboembolic pulmonary hypertension (CTEPH) in patients with pulmonary embolism (PE), new and innovative therapies must continue to be explored to help prevent these potentially devastating conditions.

Pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension

BACKGROUND

Management and outcome of patients with operable chronic thromboembolic pulmonary hypertension (CTEPH) who underwent pulmonary endarterectomy (PEA) at a large German referral center were investigated.

METHODS

In Germany, 394 PEAs were performed in 2014 and 2015 with an in-hospital mortality rate of 5.8%. Of these, 253 patients (64.2%) were treated at the Kerckhoff Clinic, Bad Nauheim, and 237 (93.7%; median age, 62 years [interquartile range [IQR], 52-72 years]; 46.0% female) were included in the present analysis.

RESULTS

On referral, 52 patients (22.0%) were treated with pulmonary arterial hypertension-specific drugs and 95 (40.4%) were treated with non-vitamin K-dependent oral anticoagulants, and 14 (5.9%) had mean pulmonary artery pressure <25 mm Hg and were classified as having chronic thromboembolic pulmonary vascular disease. PEA was feasible in 236 (99.6%) patients with median duration of surgery of 397 minutes (IQR, 363-431 minutes). Periprocedural (0%) and in-hospital (2.5%) mortality rates were very low. Forty-two patients (17.7%) had intraoperative complications, and 60 (25.3%) had post-operative complications. The duration of surgery was the only predictor of in-hospital mortality (≥500 minutes; odds ratio [OR], 32.0; 95% confidence interval [CI], 5.5-187.6) and the only independent predictor of intraoperative (≥440 minutes; OR, 10.8; 95% CI, 4.4-26.5) and post-operative (≥390 minutes; OR, 2.4; 95%CI, 1.1-5.7) complications. Only intraoperative complications independently predicted a longer duration of surgery (≥397 minutes; OR, 5.0; 95% CI, 2.2-11.2).

CONCLUSIONS

In an experienced center with multidisciplinary diagnostic and therapeutic approaches, PEA is safe. Prognosis was mainly determined by occurrence of intraoperative complications and duration of surgery rather than patients' pre-operative status.