Incidence of recurrent venous thromboembolism and of chronic thromboembolic pulmonary hypertension in patients after a first episode of pulmonary embolism

Chronic thromboembolic pulmonary hypertension: the diagnostic assessment

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) presents a significant diagnostic challenge due to its complex and often nonspecific clinical manifestations. This review outlines a comprehensive approach to the diagnostic assessment of CTEPH, emphasizing the importance of a high index of suspicion in patients with unexplained dyspnea or persistent symptoms post-acute pulmonary embolism. We discuss the pivotal role of multimodal imaging, including echocardiography, ventilation/perfusion scans, CT pulmonary angiography, and magnetic resonance imaging, in the identification and confirmation of CTEPH. Furthermore, the review highlights the essential function of right heart catheterization in validating the hemodynamic parameters indicative of CTEPH, establishing its definitive diagnosis. Advances in diagnostic technologies and the integration of a multidisciplinary approach are critical for the timely and accurate diagnosis of CTEPH, facilitating early therapeutic intervention and improving patient outcomes. This manuscript aims to equip clinicians with the knowledge and tools necessary for the efficient diagnostic workflow of CTEPH, promoting awareness and understanding of this potentially treatable cause of pulmonary hypertension.

Extracorporal Membrane Oxygenation in Massive Pulmonary Embolism

BACKGROUND

Massive pulmonary embolism (MPE) carries significant 30-day mortality risk, and a change in societal guidelines has promoted the increasing use of extracorporeal membrane oxygenation (ECMO) in the immediate management of MPE-associated cardiovascular shock. This narrative review examines the current status of ECMO in MPE.

METHODS

A literature review was performed from 1982 to 2022 searching for the terms "Pulmonary embolism" and "ECMO," and the search was refined by examining those publications that covered MPE.

RESULTS

In the patient with MPE, veno-arterial ECMO is now recommended as a bridge to interventional therapy. It can reliably decrease right ventricular overload, improve RV function, and allow hemodynamic stability and restoration of tissue oxygenation. The use of ECMO in MPE has been associated with lower mortality in registry reviews, but there has been no significant difference in outcomes between patients treated with and without ECMO in meta-analyses. Applying ECMO is also associated with substantial multisystem morbidity due to systemic inflammatory response, bleeding with coagulopathy, hemorrhagic stroke, renal dysfunction, and acute limb ischemia, which must be factored into the outcomes.

CONCLUSIONS

The application of ECMO in MPE should be combined with an aggressive interventional pulmonary interventional program and should strictly adhere to the current selection criteria.

The association of the prothrombin A19911G single-nucleotide polymorphism and the risk of venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

The study employed meta-analysis to provide a comprehensive synthesis of evidence regarding the association between the prothrombin A19911G polymorphism and the risk of venous thromboembolism (VTE).

METHOD

The databases were searched to identify studies investigating the association between the prothrombin A19911G polymorphism and the risk of VTE. Meta-analysis was conducted using Stata 14.0 software.

RESULTS

A total of five literature studies were included, involving 14,001 participants. Meta-analysis demonstrated that prothrombin A19911G polymorphism increased the risk of VTE (G vs A: OR = 1.17, 95% CI = 1.11-1.22, p < .00001; GG + AG vs AA: OR = 1.22, 95% CI = 1.13-1.31, p < .00001; GG vs AG + AA: OR = 1.23, 95% CI = 1.14-1.33, p < .00001; AG vs AA: OR = 1.15, 95% CI = 1.06-1.25, p = .0006; GG vs AA: OR = 1.34, 95% CI = 1.22-1.48, p < .00001).

CONCLUSION

The polymorphism of prothrombin A19911G enhances the susceptibility to VTE.

Pathogenesis, Diagnosis, and Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is thought to occur as a sequelae of thromboembolic processes in the pulmonary vasculature. The pathophysiology of CTEPH is multifactorial, including impaired fibrinolysis, endothelial dysregulation, and hypoxic adaptations. The diagnosis of CTEPH is typically delayed considering the nonspecific nature of the symptoms, lack of screening, and relatively low incidence. Diagnostic tools include ventilation-perfusion testing, echocardiography, cardiac catheterization, and pulmonary angiography. The only potentially curative treatment for CTEPH is pulmonary endarterectomy However, approximately 40% of patients are inoperable. Currently, only Riociguat is Food and Drug Administration approved specifically for CTEPH, with additional drug trials underway.

Frequency and characterization of CTEPH and CTEPD according to the mPAP threshold > 20 mm Hg: Retrospective analysis from data of a prospective PE aftercare program

BACKGROUND

The influence of the new pulmonary hypertension (PH) definition on the incidence of chronic thromboembolic PH (CTEPH) is unclear. The incidence of chronic thromboembolic pulmonary disease without PH (CTEPD) is unknown.

OBJECTIVES

To determine the frequency of CTEPH and CTEPD using the new mPAP cut-off >20 mmHg for PH in patients who have suffered an incidence of pulmonary embolism (PE) and were recruited into an aftercare program.

METHODS

In a prospective two-year observational study based on telephone calls, echocardiography and cardiopulmonary exercise tests, patients with findings suspicious for PH received an invasive work-up. Data from right heart catheterization were used to identify patients with or without CTEPH/CTEPD.

RESULTS

Two years after acute PE (n = 400) we found an incidence of 5.25% for CTEPH (n = 21) and 5.75% for CTEPD (n = 23) according to the new mPAP threshold >20 mmHg. Five of 21 patients with CTEPH and 13 of 23 patients with CTEPD showed no signs of PH in echocardiography. CTEPH and CTEPD subjects showed a reduced VO₂ peak and work rate in cardiopulmonary exercise testing (CPET). The capillary end-tidal CO₂ gradient was comparably elevated in CTEPH and CTEPD, but it was normal in the Non-CTEPD-Non-PH group. According to the PH definition provided by the former guidelines, only 17 (4.25%) patients have been diagnosed with CTEPH and 27 individuals (6.75%) were classified having CTEPD.

CONCLUSIONS

Using mPAP >20 mmHg for diagnosis of CTEPH leads to an increase of 23.5% of CTEPH diagnosis. CPET may help to detect CTEPD and CTEPH.

Antiphospholipid antibodies in chronic thromboembolic pulmonary hypertension

Acquired thrombophilia and in particular the presence of antiphospholipid antibodies (aPL) may play an important role in the development of chronic thromboembolic pulmonary hypertension (CTEPH). Young patients suffering from an episode of unprovoked pulmonary embolism (PE), or PE provoked by mild risk factors, should be tested for aPL. In case of a positive result, they should be closely followed up and lifelong anticoagulant treatment should be considered. Indeed, aPL-induced thrombophilia may favor PE recurrence with the consequence of possible CTEPH development. The aPL profiles play an important role in this pathway. Patients with PE and triple positivity (lupus anticoagulant, LAC, anti-cardiolipin, aCL, and anti-β2-glycoprotein I, aβ2GPI) are at the highest risk of recurrence and deserve maximum protection by anticoagulant treatment with warfarin.

Chronic Thromboembolic Pulmonary Hypertension in Females: Clinical Features and Survival

Sparse data are available on the female-specific features of chronic thromboembolic pulmonary hypertension (CTEPH). We prospectively enrolled 160 consecutive female patients who were firstly diagnosed with CTEPH between 2013 and 2019 to explore their clinical phenotypes, treatment patterns, and long-term survival. The patients’ mean age was 54.7 ± 13.8 years, 70.6% provided a confirmed history of venous thromboembolism, 46 (28.8%) patients underwent pulmonary endarterectomy (PEA), 65 (40.6%) received balloon pulmonary angioplasty (BPA), and 49 (30.6%) were treated with medical therapy alone. The patients were followed for a median of 51 (34–70) months; three patients were lost to follow-up, and twenty-two patients died. The estimated survival rates at 1, 3, 5, and 7 years were 98.1% (95% CI 96.0–100), 96.9% (95% CI 94.2–99.6), 85.1% (95% CI 78.1–92.2), and 76.2% (95% CI 65.2–87.2), respectively. After adjusting for the confounders, the results of the multivariate Cox analysis showed that the presence of anemia (5.56, 95% CI 1.6–19.22) was associated with an increased risk of all-cause death, and compared with medical treatment, receiving PEA and BPA decreased the risk of death by 74% (0.26, 95% CI 0.07–0.97) and 86% (0.14, 95% CI 0.04–0.57), respectively. In conclusion, in the modern era of CTEPH treatment, invasive revascularization combined with targeted therapy display good clinical outcomes for females; anemia should be actively modified, which may lead to clinical improvements. (ClinicalTrials.gov Identifier: NCT05360992).

Molecular Pathways in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension is a multifactorial, chronic disease process that leads to pulmonary arterial endothelial dysfunction and smooth muscular hypertrophy, resulting in impaired pliability and hemodynamics of the pulmonary vascular system, and consequent right ventricular dysfunction. Existing treatments target limited pathways with only modest improvement in disease morbidity, and little or no improvement in mortality. Ongoing research has focused on the molecular basis of pulmonary arterial hypertension and is going to be important in the discovery of new treatments and genetic pathways involved. This review focuses on the molecular pathogenesis of pulmonary arterial hypertension.

Surgical Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension is a progressive disease, which may lead to severe right ventricular dysfunction and debilitating symptoms. Pulmonary thromboendarterectomy (PTE) provides the best opportunity for complete resolution of obstructing thromboembolic disease and functional improvement in appropriately selected patients. In this article, the authors review preoperative workup, patient selection, operative technique, postoperative care, and outcomes after PTE.

Dual-Energy CT Pulmonary Angiography for the Assessment of Surgical Accessibility in Patients with Chronic Thromboembolic Pulmonary Hypertension

We assessed the value of dual-energy CT pulmonary angiography (CTPA) for classification of the level of disease in chronic thromboembolic pulmonary hypertension (CTEPH) patients compared to the surgical Jamieson classification and prediction of hemodynamic changes after pulmonary endarterectomy. Forty-three CTEPH patients (mean age, 57 ± 16 years; 18 females) undergoing CTPA prior to surgery were retrospectively included. “Proximal” and “distal disease” were defined as L1 and 2a (main and lobar pulmonary artery [PA]) and L2b-4 (lower lobe basal trunk to subsegmental PA), respectively. Three radiologists had a moderate interobserver agreement for the radiological classification of disease (k = 0.55). Sensitivity was 92–100% and specificity was 24–53% to predict proximal disease according to the Jamieson classification. A median of 9 segments/patient had CTPA perfusion defects (range, 2–18 segments). L1 disease had a greater decrease in the mean pulmonary artery pressure (p = 0.029) and pulmonary vascular resistance (p = 0.011) after surgery compared to patients with L2a to L3 disease. The extent of perfusion defects was not associated with the level of disease or hemodynamic changes after surgery (p > 0.05 for all). CTPA is highly sensitive for predicting the level of disease in CTEPH patients with a moderate interobserver agreement. The radiological level of disease is associated with hemodynamic improvement after surgery.

Higher Incidence of Chronic Thromboembolic Pulmonary Hypertension After Acute Pulmonary Embolism in Asians Than in Europeans: A Meta-Analysis

Aim: To summarize the incidence of right heart catheter diagnosed chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism (PE) in a meta-analysis. Methods: Cohort studies reporting the incidence of CTEPH after acute PE were identified via search of Medline, Embase, China National Knowledge Infrastructure and WanFang databases. Results: Twenty-two cohort studies with 5,834 acute PE patients were included. Pooled results showed that the overall incidence of CTEPH was 2.82% (95% CI: 2.11-3.53%). Subgroup analyses showed higher incidence of CTEPH in Asians than Europeans (5.08 vs. 1.96%, p = 0.01), in retrospective cohorts than prospective cohorts (4.75 vs. 2.47%, p = 0.02), and in studies with smaller sample size than those with larger sample size (4.57 vs. 1.71%, p < 0.001). Stratified analyses showed previous venous thromboembolic events and unprovoked PE were both significantly associated with increased risk of CTEPH (OR = 2.57 and 2.71, respectively; both p < 0.01). Conclusions: The incidence of CTEPH after acute PE is ~3% and the incidence is higher in Asians than Europeans. Efforts should be made for the early diagnosis and treatment of CTEPH in PE patients, particularly for high-risk population.

Balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by chronic stenosis or obstruction of the pulmonary arteries due to thromboembolism. Although previous studies have shown untreated CTEPH has a poor prognosis, the establishment of gold-standard therapies including pulmonary endarterectomy, balloon pulmonary angioplasty (BPA), and medical therapy has improved hemodynamics and right ventricular function, leading to good long-term survival. BPA is an important therapy for patients with inoperable CTEPH, although the procedure is currently limited to specific institutions and operators. This review discusses the development of the rapidly evolving field of CTEPH that includes improvements in imaging modalities and advances in surgical and interventional techniques.

Pulmonary manifestations of antiphospholipid syndrome: a retrospective analysis of 67 patients

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by arterial and/ or venous thrombosis accompanied by persistently elevated levels of antiphospholipid antibodies (aPLs). The aim of this study is to evaluate the pulmonary manifestations of APS and compare the levels of aPLs in patients with and without pulmonary involvement. We retrospectively reviewed the files of patients with the diagnosis of APS between October 2010 and May 2017. Demographic data, clinical, radiological and laboratory findings were recorded. The study included 67 patients (56 female/11 male) with a mean age of 39 ± 13 years. Pulmonary manifestations such as parenchymal and/or vascular involvement were seen in 12 (17.9%) patients. The patients with and without pulmonary manifestations were not significantly different in terms of age (p = 0.46), comorbidities (p = 0.48) and APS duration (p = 0.66). Acute pulmonary thromboembolism (PE) was determined in 11 (16.4%), alveolar hemorrhage in 2 (3%) patients. Four patients with acute PE (36%) developed chronic thromboembolic pulmonary hypertension (CTEPH). One patient developed both CTEPH and diffuse alveolar hemorrhage after acute PE during follow up. Antiphosholipid antibody IgM was highly positive in patients with PE compared to patients without PE (p = 0.005). Other antibodies and lupus anticoagulant were not significantly different in patients with and without PE. None of the patients were deceased due to pulmonary manifestations of APS. PE was the most common pulmonary manifestation of APS. The development of CTEPH was high among APS patients. Patients with APS should be closely followed for the onset of PE and CTEPH.

Clinical and imaging outcomes after intermediate- or high-risk pulmonary embolus

Long-term outcomes after acute pulmonary embolism vary from complete resolution to chronic thromboembolic pulmonary hypertension (CTEPH). Guidelines after acute pulmonary embolism are generally limited to anticoagulation duration. We assessed patients with estimated prognosis >1 year in our pulmonary hypertension clinic 2-4 months after treatment for intermediate- or high-risk acute pulmonary embolism. At follow-up, ventilation-perfusion scan and echocardiogram were offered. The aim of this study was to assess for recurrent symptomatic disease, residual imaging defects or right ventricular dysfunction, and functional disability after acute management of pulmonary embolism. After treatment for acute intermediate- or high-risk pulmonary embolism, 104 patients followed up in pulmonary hypertension clinic. Of those, 55% of patients had self-reported limitation in activity. No patients had symptomatic recurrence of pulmonary embolism. Forty-eight percent of patients had residual perfusion defects on perfusion imaging, while 91% of patients had either normal or only mildly enlarged right ventricles. We identified heart failure preserved ejection fraction, iron deficiency, and obstructive sleep apnea as significant contributors to breathlessness. Treatment of these conditions was associated with improvement. Surprisingly, we diagnosed CTEPH in nine patients; for some, chronic thrombus may already have been present at the time of index evaluation. Our findings suggest that follow-up in a dedicated pulmonary hypertension clinic 2-4 months after acute intermediate- or high-risk pulmonary embolism may add value to patient care. We identified treatable comorbidities that could be contributing to post-pulmonary embolism syndrome as well as CTEPH.

Clinical Updates on the Diagnosis and Management of Chronic Thromboembolic Pulmonary Hypertension

Introduction: Chronic thromboembolic pulmonary hypertension (CTEPH) is a known sequela after acute pulmonary embolism (PE). It is a debilitating disease, and potentially fatal if left untreated. This review provides a clinically relevant overview of the disease and discusses the usefulness and limitations of the various investigational and treatment options. Methods: A PubMed search on articles relevant to pulmonary embolism, pulmonary hypertension, chronic thromboembolic pulmonary hypertension, pulmonary endarterectomy, and balloon pulmonary angioplasty were performed. A total of 68 articles were found to be relevant and were reviewed. Results: CTEPH occurs as a result of non-resolution of thrombotic material, with subsequent fibrosis and scarring of the pulmonary arteries. Risk factors have been identified, but the underlying mechanisms have yet to be fully elucidated. The cardinal symptom of CTEPH is dyspnoea on exertion, but the diagnosis is often challenging due to lack of awareness. The ventilation/perfusion scan is recommended for screening for CTEPH, with other modalities (eg. dual energy computed tomography pulmonary angiography) also being utilised in expert centres. Conventional pulmonary angiography with right heart catherisation is important in the final diagnosis of CTEPH. Conclusion: Operability assessment by a multidisciplinary team is crucial for the management of CTEPH, as pulmonary endarterectomy (PEA) remains the guideline recommended treatment and has the best chance of cure. For inoperable patients or those with residual disease post-PEA, medical therapy or balloon pulmonary angioplasty are potential treatment options. Keywords: Balloon pulmonary angioplasty, Chronic thromboembolic pulmonary hypertension, Pulmonary embolism, Pulmonary endarterectomy, Pulmonary hypertension

Research progress on the pathogenesis of CTEPH

Chronic thromboembolic pulmonary hypertension (CTEPH) is an established long-term complication of pulmonary thromboembolism (PTE). However, studies have shown that many patients with a definitive CTEPH diagnosis have no history of symptomatic PTE, suggesting that PTE is not the only cause of CTEPH. Despite extensive progress in research on pulmonary hypertension in recent years, due to a lack of relevant studies on the pathophysiology of CTEPH, implementing pulmonary endarterectomy (PEA) in patients has many challenges, and the prognosis of patients with CTEPH is still not optimistic. Therefore, revealing the pathogenesis of CTEPH would be of great significance for understanding the occurrence and development of CTEPH, developing relevant drug treatment studies and formulating intervention strategies, and may provide new preventive measures. This article summarizes the current research progress in CTEPH pathogenesis from the perspective of risk factors related to medical history, abnormal coagulation and fibrinolytic mechanisms, inflammatory mechanisms, genetic susceptibility factors, angiogenesis, in situ thrombosis, vascular remodeling, and other aspects.

Post-Intensive Care Unit Follow-up of Pulmonary Embolism

The post-intensive care unit follow-up of patients hospitalized with pulmonary embolism is crucial to the comprehensive care of these patients. This article discusses the recommended duration of intensive care unit stay after high-intermediate risk or high-risk pulmonary embolism, duration of anticoagulation after venous thromboembolism event, retrieval of inferior vena cava filters, post-hospitalization follow-up and assessment of right ventricular function, and assessment for chronic thromboembolic pulmonary hypertension, chronic thromboembolic disease, and post-pulmonary embolism syndrome.

Risk Stratification of Acute Pulmonary Embolism and Determining the Effect on Chronic Cardiopulmonary Complications: The REACH Study

Introduction  Patients with acute pulmonary embolism (PE) are at risk of developing chronic complications including the post-PE syndrome with reduced cardiopulmonary function and chronic thromboembolism pulmonary hypertension (CTEPH). Risk stratification at PE diagnosis is an important tool in predicting early mortality; however, its use in predicting chronic complications has not been evaluated. Objective  This study investigates the effect of initial risk stratification of intermediate risk and standard risk PE on the rate of development of chronic complications including right ventricular (RV) dysfunction, residual perfusion defects, and CTEPH. Methods  Cases of acute PE ( n  = 1,524) were identified using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification discharge diagnosis coding for PE. Evidence of RV dysfunction and systolic blood pressure < 90 mm Hg were used to risk stratify into high, intermediate and standard risk PE. Results  There were 508 patients included in the analysis. Intermediate risk PE was associated with higher rates of persistent RV dysfunction as well as residual perfusion defects on repeat imaging. The overall rate of CTEPH was low (0.6%) and there was no difference between the intermediate risk and standard risk PE groups. Conclusion  These findings demonstrate that acute intermediate risk PE is associated with higher rates of RV dysfunction on follow-up imaging than standard risk PE. However, the rate of CTEPH was similar between the two groups and overall the CTEPH rate was low among all patients with intermediate and standard risk PE.

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.

Evaluation of the Incidence of Chronic Thromboembolic Pulmonary Hypertension 1 Year After First Episode of Acute Pulmonary Embolism: A Cohort Study

PURPOSE

Chronic thromboembolic pulmonary hypertension (CTEPH) is an important complication after acute pulmonary embolism (PE) with considerable morbidity and mortality. The aim of this study was to estimate the CTEPH incidence in a cohort after the first occurrence of PE.

METHODS

We conducted a 1-year follow-up cohort study between 2015 and 2018 to assess the incidence of CTEPH in 474 patients with their first acute episode of PE. For the diagnosis of CTEPH, patients with unexplained persistent dyspnea during follow-up underwent transthoracic echocardiography, right heart catheterization, ventilation-perfusion lung scanning, and CT pulmonary angiography.

RESULTS

Overall, 317 patients were included in the study. The mean age of the patients was 56.5 ± 16 years. One hundred and three patients (32%) had exertional dyspnea at the 1-year follow-up. Patients with evidence of pulmonary hypertension (PH) on echocardiography underwent right heart catheterization. Eleven patients (18%) had no PH (mPAP < 25 mmHg); 47 patients (81%) had mPAP > 25 mmHg. Fifteen patients had PAWP > 15 mmHg, including those with underlying left heart problems or valvular diseases. There were 32 patients with PAH (mPAP > 25 mmHg and PVR > 3 WU) undergoing CTEPH studies; 22 patients (6.9%) had multiple segmental defects suggesting CTEPH on a perfusion scan.

CONCLUSION

The incidence of CTEPH observed in this study 1 year after the first episode of acute PE was approximately 6.9%. This incidence seems to be high in our population, and diagnostic and therapeutic strategies for the early identification of CTEPH are needed.

Risk of recurrent venous thromboembolism after acute pulmonary embolism: Role of residual pulmonary obstruction and persistent right ventricular dysfunction. A meta-analysis

Essentials Debated is the role of residual pulmonary obstruction (RPO) in predicting venous thromboembolism. Whether right ventricular dysfunction (RVD) predicts recurrent venous thromboembolism is unknown. 15 studies on RPO and 4 on RVD and venous thromboembolism were included in this meta-analysis. RPO is a predictor of recurrent venous thromboembolism when assessed by perfusion lung scan. RVD after acute pulmonary embolism is not associated with recurrent venous thromboembolism.

BACKGROUND

There is conflicting evidence regarding the role of residual pulmonary obstruction (RPO) or persistent right ventricular dysfunction (RVD) after pulmonary embolism (PE) as a predictor of recurrent venous thromboembolism (VTE). The aim of this study was to assess whether RPO or persistent RVD after PE is associated with recurrent VTE.

METHODS

MEDLINE and EMBASE were searched through December 2018. Studies reporting on (a) RPO either on computed tomography (CT) angiography or perfusion lung scan, or RVD on echocardiography or CT angiography, after therapeutic anticoagulation for the acute PE, and (b) recurrent VTE, were included in this meta-analysis.

RESULTS

RPO was associated with an increased risk of recurrent VTE (16 studies; 3472 patients; odds ratio [OR] 2.22; 95% confidence interval [CI] 1.61-3.05; I2  = 26%); the association was statistically significant for lung scan-detected RPO (11 studies; 2916 patients; OR 2.21; 95% CI 1.63-3.01) but not for CT angiography-detected RPO (five studies; 556 patients; OR 2.56; 95% CI 0.82-7.94). No significant association was found between persistent RVD and recurrent VTE (four studies; 852 patients; OR 1.62; 95% CI 0.63-4.17).

CONCLUSIONS

RPO is a predictor of recurrent VTE after a first acute PE, mainly when assessed by perfusion lung scan.

Identifying chronic thromboembolic pulmonary hypertension through the French national hospital discharge database

Chronic thromboembolic pulmonary hypertension (CTEPH), a rare pulmonary vascular disease, is often misdiagnosed due to nonspecific symptoms. The objective of the study was to develop, refine and validate a case ascertainment algorithm to identify CTEPH patients within the French exhaustive hospital discharge database (PMSI), and to use it to estimate the annual number of hospitalized patients with CTEPH in France in 2015, as a proxy for disease prevalence. As ICD-10 coding specifically for CTEPH was not available at the time of the study, a case ascertainment algorithm was developed in close collaboration with an expert committee, using a two-step process (refinement and validation), based on matched data from PMSI and hospital medical records from 2 centres. The best-performing algorithm (specificity 95%, sensitivity 70%) consisted of ≥1 pulmonary hypertension (PH) diagnosis during 2015 and any of the following criteria over 2009-2015: (i) CTEPH interventional procedure, (ii) admission for PH and pulmonary embolism (PE), (iii) PE followed by hospitalization in competence centre then in reference centre, (iv) history of PE and right heart catheterization. Patients with conditions suggestive of pulmonary arterial hypertension were excluded. A total of 3,138 patients hospitalized for CTEPH was estimated for 2015 (47 cases/million, range 43 to 50 cases/million). Assuming that patients are hospitalized at least once a year, the present study provides an estimate of the minimal prevalence of CTEPH and confirms the heavy burden of this disease.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of pulmonary embolism and a major cause of chronic PH leading to right heart failure and death. Lung ventilation/perfusion scintigraphy is the screening test of choice; a normal scan rules out CTEPH. In the case of an abnormal perfusion scan, a high-quality pulmonary angiogram is necessary to confirm and define the pulmonary vascular involvement and prior to making a treatment decision. PH is confirmed with right heart catheterisation, which is also necessary for treatment determination. In addition to chronic anticoagulation therapy, each patient with CTEPH should receive treatment assessment starting with evaluation for pulmonary endarterectomy, which is the guideline recommended treatment. For technically inoperable cases, PH-targeted medical therapy is recommended (currently riociguat based on the CHEST studies), and balloon pulmonary angioplasty should be considered at a centre experienced with this challenging but potentially effective and complementary intervention.

Fatal recurrent VTE after anticoagulant treatment for unprovoked VTE: a systematic review

Current guidelines recommend long-term anticoagulant therapy in patients with unprovoked venous thromboembolism (VTE). The risk of fatal recurrent VTE after treatment discontinuation (versus that of fatal bleeding during anticoagulation) is of particular relevance in the decision to continue or stop anticoagulation after the first 3 months. Our primary aim was to provide a point-estimate of the yearly rate of fatal recurrent VTE and VTE case-fatality rate in patients with unprovoked VTE after anticoagulation cessation. Data were extracted from both randomised controlled trials and observational studies published before May 1, 2017. The pooled fatality rates were calculated using a random-effects model. 18 studies with low-to-moderate bias were included in the primary analysis, totalling 6758 patients with a median (range) follow-up duration of 2.2 (1–5) years. After anticoagulation cessation, the weighted pooled rate of VTE recurrence was 6.3 (95% CI 5.4–7.3) per 100 patient-years and the weighted pooled rate of fatal recurrent VTE was 0.17 (95% CI 0.047–0.33) per 100 patient-years, for a case-fatality rate of 2.6% (95% CI 0.86–5.0). These numbers are a solid benchmark for comparison to the risks associated with long-term anticoagulation treatment for the decision on the optimal duration of treatment of patients with unprovoked VTE.

Incidence and risk factors of chronic thromboembolic pulmonary hypertension in patients with diagnosis of pulmonary embolism for the first time in real world

BACKGROUND

The incidence and risk factors of chronic thromboembolic pulmonary hypertension (CTEPH) in patients with acute pulmonary embolism (PE) have been well reported. However, in real world, patients diagnosed with PE for the first time were usually composed of acute PE, sub-acute PE, and chronic PE, and the cumulative incidence and risk factors of CTEPH in this cohort were still unknown.

METHODS

A prospective, long-term, follow-up study was conducted to assess the incidence of symptomatic CTEPH in consecutive patients with PE diagnosed for the first time. Patients with unexplained persistent dyspnea during follow-up underwent transthoracic echocardiography and, if the findings indicated pulmonary hypertension, ventilation-perfusion lung scanning and right heart catheterization. CTEPH was confirmed if perfusion defects were present, mean pulmonary artery pressure (mPAP) ≥25 mmHg and pulmonary artery wedge pressure (PAWP) ≤15 mmHg.

RESULTS

The cumulative incidence of CTEPH in patients with PE diagnosed for the first time was 11.2% at 3 months, 12.7% at 1 year, 13.4% at 2 years, and 14.5% at 3 years. The following factors increased the risk of CTEPH: time from symptoms to treatment of PE ≥1 month (odds ratio (OR), 14.77), intermediate (OR, 37.63) to high risk PE (OR, 39.81), segmental and sub-segmental branch location of embolism (OR, 8.30) and PE-related primary risk factors (OR, 5.01). 9.4% of CTEPH patients developed from acute PE, and 90.6% from sub-acute and chronic PE.

CONCLUSIONS

In real world, CTEPH is a relatively common and serious complication in PE patients diagnosed for the first time. Early diagnosis and treatment of PE will decrease the incidence of CTEPH in these unspecified patients.

Chronic thromboembolic pulmonary hypertension (CTEPH): Updated Recommendations from the Cologne Consensus Conference 2018

Chronic thromboembolic pulmonary hypertension (CTEPH) is a subgroup of pulmonary hypertension that differs from all other forms of PH in terms of its pathophysiology, patient characteristics and treatment. For implementation of the European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension in Germany, the Cologne Consensus Conference 2016 was held and last updated in spring of 2018. One of the working groups was dedicated to CTEPH, practical and controversial issues were commented and updated. In every patient with suspected PH, CTEPH or chronic thromboembolic disease (CTED, i.e. symptomatic residual vasculopathy without pulmonary hypertension) should be excluded. Primary treatment is surgical pulmonary endarterectomy (PEA) in a multidisciplinary CTEPH centre. Inoperable patients or patients with persistent or recurrent CTEPH after PEA are candidates for targeted drug therapy. There is increasing experience with balloon pulmonary angioplasty (BPA) for inoperable patients; this option, like PEA, is reserved for specialised centres with expertise in this treatment method.

Incidence and risk factors of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: a systematic review and meta-analysis of cohort studies

BACKGROUND

The incidence and risk factors of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism (PE) were still controversial. A systematic review and meta-analysis was conducted to assess the incidence and risk factors of CTEPH after acute PE.

METHODS

Embase, Medline, China National Knowledge Infrastructure, Wanfang databases, and various reference lists were searched to identify studies published up to May 2018. Only cohort studies that used right heart catheterization for CTEPH diagnosis were included. The study quality was assessed using the Newcastle-Ottawa Scale (NOS). All analyses were conducted with the meta package in R software (3.2.2).

RESULTS

Fifteen studies met the inclusion criteria. The overall incidence of CTEPH after acute PE, with a median follow-up from 6 to 94.3 months, was 3.13% (95% CI: 2.11-4.63%). The incidence of studies from China [4.46% (95% CI: 1.68-11.32%)] was slightly higher than from Europe [2.82% (95% CI: 1.82-4.34%)]. However, there was no significant difference between these two groups (P=0.39). Subgroup analyses of confirmed diagnostic method showed that compared studies using right heart catheterization [3.25% (95% CI: 2.12-4.97%)], studies using right heart catheterization combined with bundled tests tended to yield a similar data [2.40% (95% CI: 0.97-5.81%), P=0.54]. Previous/recurrent PE or previous VTE, idiopathic PE and right heart dysfunction were considered as risk factors of CTEPH in patients with a previous PE.

CONCLUSIONS

CTEPH is not a rare complication of acute PE. Close follow-up and implementation of a comprehensive screening program are important, especially in patients with independent risk factors.

Results from more than 20 years of surgical pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension in Denmark

OBJECTIVES

Chronic thromboembolic pulmonary hypertension is a fatal disease if left untreated, and pulmonary endarterectomy (PEA) is the potentially curable treatment of choice. We aimed to estimate the current in-hospital mortality rate, complication rate and long-term survival for patients with chronic thromboembolic pulmonary hypertension undergoing PEA in Denmark.

METHODS

All chronic thromboembolic pulmonary hypertension patients who underwent PEA in the period 1994 till 2016 were consecutively enrolled in our single-centre study. All patients were followed from PEA until death or end of study. Kaplan-Meier survival analysis was used to estimate the 3-, 5- and 10-year survival rates with 95% confidence interval (CI).

RESULTS

In total, 239 patients were operated in the study period. A significant reduction in mean pulmonary arterial pressure from 48 mmHg to 33 mmHg, and pulmonary vascular resistance from 800 dynes s cm-5 to 289 dynes s cm-5, was observed during the first postoperative day after PEA. Overall, in-hospital mortality rate was 8.4%. A significantly lower mortality rate in the late decade (2005-2016) compared with the early decade (1994-2004) was observed (4.3% vs 22.6%, P < 0.001). In-hospital mortality during the last 5 years (n = 80) was 2.5%. Three-, 5- and 10-year survival rates were 84% (CI: 77.8-88), 77% (CI: 70.7-82.7) and 62% (CI: 53-69.1), respectively. The majority of patients improved in World Health Organization functional class from III/IV to I/II and significantly increased their 6-min walking distance.

CONCLUSIONS

PEA in Denmark is associated with a low in-hospital mortality rate and significant improvements in both haemodynamics and exercise capacity. Long-term survival is excellent and similar to high-volume international centres.

Incidence and risk factors of chronic thromboembolic pulmonary hypertension following venous thromboembolism, a population-based cohort study in England

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of unresolved organised pulmonary emboli/thrombi obstructing the major pulmonary arteries. The aim of this study was to estimate the incidence and risk factors of CTEPH in a cohort with first venous thromboembolism (VTE). This was a population-based cohort study of patients with first VTE and no active cancer in England between 2001 and 2012. CTEPH was assessed using a rigorous case-ascertainment algorithm. Risk factors for CTEPH were studied using a nested case-control approach by matching CTEPH cases to VTE patients without CTEPH. Adjusted odds ratios (OR) of comorbidities were estimated from conditional logistic regression. During 81,413 person-years of follow-up among 23,329 patients with first VTE (mean follow-up 3.5 years; maximum 11.0 years) 283 patients were diagnosed with CTEPH (incidence rate 3.5 per 1000 person-years); cumulative incidence was 1.3% and 3.3% at 2 and 10 years after pulmonary embolism, and 0.3% and 1.3% following deep vein thrombosis (DVT), respectively. Risk factors for CTEPH included age over 70, OR 2.04 (95% CI 1.23 to 3.38), female gender, 1.44 (1.06 to 1.94), pulmonary embolism at first VTE, 3.11 (2.23 to 4.35), subsequent pulmonary embolism and DVT, 3.17 (2.02 to 4.96) and 2.46 (1.34 to 4.51) respectively, chronic obstructive pulmonary disease 3.17 (2.13 to 4.73), heart failure 2.52 (1.76 to 3.63) and atrial fibrillation, 2.42 (1.71 to 3.42). CTEPH develops most commonly after pulmonary embolism and less frequently after DVT. Awareness of risk factors may increase referrals to specialised centres for confirmation of CTEPH and initiation of specific treatment.

Chronic thromboembolic pulmonary hypertension: emerging endovascular therapy

Chronic thromboembolic pulmonary hypertension (CTEPH) is a debilitating but potentially reversible complication of chronic pulmonary thromboembolic disease characterized by progressive right heart dysfunction secondary to pulmonary arterial stenosis or occlusion. Balloon pulmonary angioplasty (BPA) has recently emerged as an alternative intervention for non-surgical candidates with CTEPH. Modern reperfusion angioplasty techniques relieve sequela of chronic pulmonary hypertension, ameliorate right ventricular failure, and improve functional status. This article will discuss the diagnosis and treatment of patients with CTEPH and the current state of endovascular management with BPA.

Multicentre observational screening survey for the detection of CTEPH following pulmonary embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe complication of pulmonary embolism. Its incidence following pulmonary embolism is debated. Active screening for CTEPH in patients with acute pulmonary embolism is yet to be recommended.

This prospective, multicentre, observational study (Multicentre Observational Screening Survey for the Detection of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) Following Pulmonary Embolism (INPUT on PE); ISRCTN61417303) included patients with acute pulmonary embolism from 11 centres in Switzerland from March 2009 to November 2016. Screening for possible CTEPH was performed at 6, 12 and 24 months using a stepwise algorithm that included a dyspnoea phone-based survey, transthoracic echocardiography, right heart catheterisation and radiological confirmation of CTEPH.

Out of 1699 patients with pulmonary embolism, 508 patients were assessed for CTEPH screening over 2 years. CTEPH incidence following pulmonary embolism was 3.7 per 1000 patient-years, with a 2-year cumulative incidence of 0.79%. The Swiss pulmonary hypertension registry consulted in December 2016 did not report additional CTEPH cases in these patients. The survey yielded 100% sensitivity and 81.6% specificity. The second step echocardiography in newly dyspnoeic patients showed a negative predictive value of 100%.

CTEPH is a rare but treatable disease. A simple and sensitive way for CTEPH screening in patients with acute pulmonary embolism is recommended.

How I use catheter-directed interventional therapy to treat patients with venous thromboembolism

Patients who present with severe manifestations of acute venous thromboembolism (VTE) are at higher risk for premature death and long-term disability. In recent years, catheter-based interventional procedures have shown strong potential to improve clinical outcomes in selected VTE patients. However, physicians continue to be routinely faced with challenging decisions that pertain to the utilization of these risky and costly treatment strategies, and there is a relative paucity of published clinical trials with sufficient rigor and directness to inform clinical practice. In this article, using 3 distinct clinical scenario presentations, we draw from the available published literature describing the natural history, pathophysiology, treatments, and outcomes of VTE to illustrate the key factors that should influence clinical decision making for patients with severe manifestations of deep vein thrombosis and pulmonary embolism. The results of a recently completed pivotal multicenter randomized trial are also discussed.

From Acute to Chronic Thromboembolic Disease

After achievement of adequate anticoagulation, the natural history of acute pulmonary emboli ranges from near total resolution of vascular perfusion to long-term persistence of hemodynamically consequential residual perfusion defects. The persistence of perfusion defects is necessary, but not sufficient, for the development of chronic thromboembolic pulmonary hypertension (CTEPH). Approximately 30% of patients have persistent defects after 6 months of anticoagulation, but only 10% of those with persistent defects subsequently develop CTEPH. A number of clinical risk factors including increasing age, delay in anticoagulation from symptom onset, and the size of the initial thrombus have been associated with the persistence of perfusion defects. Likewise, a number of cellular and molecular pathways have been implicated in the failure of thrombus resolution, including impaired fibrinolysis, altered fibrinogen structure and function, increased local or systemic inflammation, and remodeling of the embolic material by neovascularization. Treatment with fibrinolytic agents at the time of initial presentation has not clearly improved the frequency or degree of recovery of pulmonary vascular perfusion. A better understanding of the interplay between clinical risk factors and pathogenic mechanisms may enhance the ability to prevent and treat CTEPH in the future.

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.

Factors associated with diagnosis and operability of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary hypertension (IPAH) share a similar clinical presentation, and a differential diagnosis requires a thorough workup. Once CTEPH is confirmed, patients who can be safely operated have to be identified. We investigated risk factors associated with CTEPH and IPAH, and the criteria for the selection of operable CTEPH patients. This case-control study included 436 consecutive patients with CTEPH and 158 with IPAH in eight European centres, between 2006 and 2010. Conditions identified as risk factors for CTEPH included history of acute venous thromboembolism (p < 0.0001), large size of previous pulmonary embolism (p = 0.0040 in univariate analysis), blood groups non-O (p < 0.0001 in univariate analysis), and older age (p = 0.0198), whereas diabetes mellitus (p = 0.0006), female gender (p = 0.0197) and higher mean pulmonary artery pressure (p = 0.0103) were associated with increased likelihood for an IPAH diagnosis. Operability of CTEPH patients was associated with younger age (p = 0.0108), proximal lesions (p ≤ 0.0001), and pulmonary vascular resistance below 1200 dyn.s.cm-5 (p = 0.0080). Non-operable CTEPH patients tended to be less differentiable from IPAH patients by risk factor analysis than operable patients. This study confirmed the association of CTEPH with history of acute venous thromboembolism and blood groups non-O, and identified diabetes mellitus and higher mean pulmonary artery pressure as factors suggesting an IPAH diagnosis. Non-operable CTEPH is more similar to IPAH than operable CTEPH regarding risk factors.

Prevalence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) has been estimated to occur in 0.1–0.5% of patients who survive a pulmonary embolism (PE), but more recent prospective studies suggest that its incidence may be much higher. The absence of initial haemodynamic evaluation at the time of PE should explain this discrepancy. We performed a prospective multicentre study including patients with PE in order to assess the prevalence and to describe risk factors of CTEPH. Follow-up every year included an evaluation of dyspnea and echocardiography using a predefined algorithm. In case of suspected CTEPH, the diagnosis was confirmed using right heart catheterisation (RHC). Signs of CTEPH were searched on the multidetector computed tomography (CT) and echocardiography performed at the time of PE. Of the 146 patients analysed, eight patients (5.4%) had suspected CTEPH during a median follow-up of 26 months. CTEPH was confirmed using RHC in seven cases (4.8%; 95%CI, 2.3 – 9.6) and ruled-out in one. Patients with CTEPH were older, had more frequently previous venous thromboembolic events and more proximal PE than those without CTEPH. At the time of PE diagnosis, patients with CTEPH had a higher systolic pulmonary artery pressure and at least two signs of CTEPH on the initial CT. After acute PE, the prevalence of CTEPH appears high. However, initial echocardiography and CT data at the time of the index PE suggest that a majority of patients with CTEPH had previously unknown pulmonary hypertension, indicating that a first clinical presentation of CTEPH may mimic acute PE.

Surgical Embolectomy for Massive and Submassive Pulmonary Embolism and Pulmonary Thromboendarterectomy for Chronic Thromboembolic Pulmonary Hypertension

Surgical therapy for massive acute pulmonary embolism has improved with the use of rapid response teams and selective bedside extracorporeal membrane oxygenation initiation. The chronic consequence of unresolved pulmonary embolism is a treatable form of pulmonary hypertension. Pulmonary thromboendarterectomy is a curative operation in selected cases, operated upon in an experienced center with the multidisciplinary team including imaging, pulmonary medicine, and cardiothoracic surgery.

Epidemiology and Pathophysiology of Chronic Thromboembolic Pulmonary Hypertension: Risk Factors and Mechanisms

Chronic thromboembolic pulmonary hypertension (CTEPH) occurs when thromboemboli travel to the pulmonary vasculature, fail to resolve, and cause elevated pulmonary arterial pressure. Untreated, this disease leads to progressive right heart failure and death. It develops in approximately 1% to 5% of patients who suffer an acute pulmonary embolism (PE) and has an overall incidence of 3 to 30 per million in the general population. While it is not entirely evident why most but not all people are able to clear this clot burden, there are known risk factors for the development of CTEPH. These include signs of right heart strain at the time of incident PE, inherited coagulopathies, inflammatory conditions, hypothyroidism, and a history of splenectomy. Since CTEPH can be treated both surgically and medically, it is critical to understand the pathophysiology of the disease so affected patients can be identified and diagnosed appropriately.

Medical Management of Pulmonary Embolism: Beyond Anticoagulation

Pulmonary embolism (PE) is a common medical condition that carries significant morbidity and mortality. Although diagnosis, anticoagulation, and interventional clot-burden reduction strategies represent the focus of clinical research and care in PE, appropriate risk stratification and supportive care are crucial to ensure good outcomes. In this chapter, we will discuss the medical management of PE from the time of presentation to discharge, focusing on the critical care of acute right ventricular failure, anticoagulation of special patient populations, and appropriate follow-up testing after acute PE.

Switching from sildenafil to riociguat for the treatment of PAH and inoperable CTEPH: Real-life experiences

Riociguat is a novel soluble guanylate cyclase stimulator that is approved for the treatment of patients with pulmonary arterial hypertension (PAH) and patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) or persistent/recurrent CTEPH after pulmonary endarterectomy (PEA). As riociguat is a relatively new drug, experience of its use in clinical practice is limited, especially in patients who would not have met the inclusion criteria for the pivotal Phase III clinical trials, PATENT-1 and CHEST-1. This article shares our initial practical and clinical experience in switching patients with PAH and CTEPH from the phosphodiesterase type-5 inhibitor sildenafil to riociguat, based on three selected case reports of patients who discontinued sildenafil therapy owing to side effects or disease progression (one patient with idiopathic PAH and two patients with persistent/recurrent CTEPH after PEA). Two cases illustrate our experience with direct switch from sildenafil to riociguat (6-8 h between the last sildenafil dose and the first riociguat dose), and one case illustrates switch to riociguat in a patient who underwent treatment with other PAH-specific therapies between stopping sildenafil and starting riociguat. Symptoms improved with riociguat therapy in two cases; in the third case the patient experienced worsening symptoms 1 month after initiating riociguat and was switched back to sildenafil. These case experiences contribute practical information to assist clinicians in the switch from sildenafil to riociguat therapy in patients with PAH or CTEPH.

The pathophysiology of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, progressive pulmonary vascular disease that is usually a consequence of prior acute pulmonary embolism. CTEPH usually begins with persistent obstruction of large and/or middle-sized pulmonary arteries by organised thrombi. Failure of thrombi to resolve may be related to abnormal fibrinolysis or underlying haematological or autoimmune disorders. It is now known that small-vessel abnormalities also contribute to haemodynamic compromise, functional impairment and disease progression in CTEPH. Small-vessel disease can occur in obstructed areas, possibly triggered by unresolved thrombotic material, and downstream from occlusions, possibly because of excessive collateral blood supply from high-pressure bronchial and systemic arteries. The molecular processes underlying small-vessel disease are not completely understood and further research is needed in this area. The degree of small-vessel disease has a substantial impact on the severity of CTEPH and postsurgical outcomes. Interventional and medical treatment of CTEPH should aim to restore normal flow distribution within the pulmonary vasculature, unload the right ventricle and prevent or treat small-vessel disease. It requires early, reliable identification of patients with CTEPH and use of optimal treatment modalities in expert centres.

An epidemiological analysis of the burden of chronic thromboembolic pulmonary hypertension in the USA, Europe and Japan

Epidemiological data for chronic thromboembolic pulmonary hypertension (CTEPH) are limited and there are conflicting reports regarding its pathogenesis.

A literature review was conducted to identify CTEPH epidemiological data up to June 2014. Data were analysed to provide estimates of the incidence of CTEPH in the USA, Europe and Japan. An epidemiological projection model derived country-specific estimates of future incidence and diagnosis rates of CTEPH.

Overall, 25 publications and 14 databases provided quantitative epidemiological data. In the USA and Europe, the crude annual incidence of diagnosed pulmonary embolism and crude annual full (i.e. diagnosed and undiagnosed) incidence of CTEPH were 66–104 and 3–5 cases per 100 000 population, respectively, while in Japan these rates were lower at 6.7 and 1.9 per 100 000 population, respectively. In 2013, 7–29% of CTEPH cases in Europe and the USA were diagnosed, and the majority of patients were in New York Heart Association functional class III/IV at diagnosis. The projection model indicated that incidence of CTEPH will continue to increase over the next decade.

These data suggest that CTEPH is underdiagnosed and undertreated, and there is an urgent need to increase awareness of CTEPH. High-quality epidemiological studies are required to increase understanding of CTEPH.

Epidemiological data suggest that CTEPH is underdiagnosed and there is an urgent need to improve disease awarenesshttp://ow.ly/J0KC3095U2W

Clinical Study of Acute Vasoreactivity Testing in Patients with Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

The clinical significance of acute vasoreactivity testing (AVT) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains unclear. We analyzed changes in hemodynamics and oxygenation dynamics indices after AVT in patients with CTEPH using patients with pulmonary arterial hypertension (PAH) as controls.

METHODS

We analyzed retrospectively the results of AVT in 80 patients with PAH and 175 patients with CTEPH registered in the research database of Beijing Chao-Yang Hospital between October 2005 and August 2014. Demographic variables, cardiopulmonary indicators, and laboratory findings were compared in these two subgroups. A long-term follow-up was conducted in patients with CTEPH. Between-group comparisons were performed using the independent-sample t-test or the rank sum test, within-group comparisons were conducted using the paired t-test or the Wilcoxon signed-rank test, and count data were analyzed using the Chi-squared test. Survival was estimated using the Kaplan-Meier method and log-rank test.

RESULTS

The rates of positive response to AVT were similar in the CTEPH (25/175, 14.3%) and PAH (9/80, 11.3%) groups (P > 0.05). Factors significantly associated a positive response to AVT in the CTEPH group were level of N-terminal pro-brain natriuretic peptide (≤1131.000 ng/L), mean pulmonary arterial pressure (mPAP, ≤44.500 mmHg), pulmonary vascular resistance (PVR, ≤846.500 dyn·s-1·m-5), cardiac output (CO, ≥3.475 L/min), and mixed venous oxygen partial pressure (PvO2, ≥35.150 mmHg). Inhalation of iloprost resulted in similar changes in mean blood pressure, mPAP, PVR, systemic vascular resistance, CO, arterial oxygen saturation (SaO2), mixed venous oxygen saturation, partial pressure of oxygen in arterial blood (PaO2), PvO2, and intrapulmonary shunt (Qs/Qt) in the PAH and CTEPH groups (all P > 0.05). The survival time in patients with CTEPH with a negative response to AVT was somewhat shorter than that in AVT-responders although the difference was not statistically significant (χ2 =3.613, P = 0.057). The survival time of patients with CTEPH who received calcium channel blockers (CCBs) was longer than that in the group with only basic treatment and not shorter than that of patients who receiving targeted drugs or underwent pulmonary endarterectomy (PEA) although there was no significant difference between the four different treatment regimens (χ2 =3.069, P = 0.381).

CONCLUSIONS

The rates of positive response to AVT were similar in the CTEPH and PAH groups, and iloprost inhalation induced similar changes in hemodynamics and oxygenation dynamics indices. A positive response to AVT in the CTEPH group was significantly correlated with milder disease and better survival. Patients with CTEPH who cannot undergo PEA or receive targeted therapy but have a positive response to AVT might benefit from CCB treatment.

Diagnosis of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is the only potentially curable form of pulmonary hypertension. Rapid and accurate diagnosis is pivotal for successful treatment. Clinical signs and symptoms can be nonspecific and risk factors such as history of venous thromboembolism may not always be present. Echocardiography is the recommended first diagnostic step. Cardiopulmonary exercise testing is a complementary tool that can help to identify patients with milder abnormalities and chronic thromboembolic disease, triggering the need for further investigation. Ventilation/perfusion (V'/Q') scintigraphy is the imaging methodology of choice to exclude CTEPH. Single photon emission computed tomography V'/Q' is gaining popularity over planar imaging. Assessment of pulmonary haemodynamics by right heart catheterisation is mandatory, although there is increasing interest in noninvasive haemodynamic evaluation. Despite the status of digital subtraction angiography as the gold standard, techniques such as computed tomography (CT) and magnetic resonance imaging are increasingly used for characterising the pulmonary vasculature and assessment of operability. Promising new tools include dual-energy CT, combination of rotational angiography and cone beam CT, and positron emission tomography. These innovative procedures not only minimise misdiagnosis, but also provide additional vascular information relevant to treatment planning. Further research is needed to determine how these modalities will fit into the diagnostic algorithm for CTEPH.

Medical Therapy Versus Balloon Angioplasty for CTEPH: A Systematic Review and Meta-Analysis

BACKGROUND

A significant number of chronic thromboembolic pulmonary hypertension (CTEPH) patients will have an inoperable disease. Medical therapy and balloon pulmonary angioplasty (BPA) have provided alternate therapeutic options for patients with inoperable CTEPH, although there are a limited number of published studies examining the outcomes. Thus, our study aims to evaluate and compare the efficacy of medical therapy and BPA in patients with inoperable CTEPH.

METHODS

An electronic search of six databases was performed and the search results were screened against established criteria for inclusion into this study. Data was extracted and meta-analytical techniques were used to analyse the data.

RESULTS

Pooled data from RCTs revealed that medical therapy, compared with a placebo, was associated with a significant improvement of at least one functional class (p=0.038). With regards to pulmonary haemodynamics, medical therapy also resulted in a significant reduction in both mean pulmonary arterial pressure (mPAP) (p=0.002) and pulmonary vascular resistance (PVR) (p<0.001). From the included observational studies, the 6-minute walk distance (6MWD) significantly increased following medical therapy by an average of 22.8% (p<0.001). The pooled improvement in 6MWD was found to be significantly higher in the BPA group when compared to medical therapy for CTEPH (p=0.001). Pooled data from available observational studies of medical therapy or BPA all demonstrated significant improvements in mPAP and PVR for pre versus post intervention comparisons. The improvement in mPAP (p=0.002) and PVR (p=0.002) were significantly greater for BPA intervention when compared to medical therapy.

CONCLUSIONS

High-quality evidence supports the use of targeted medical therapy in improving haemodynamics in patients with inoperable CTEPH. There is only moderate-quality evidence from observational studies supporting the efficacy of BPA in improving both haemodynamics and exercise capacity. Further RCTs and prospective observational studies comparing medical therapy and BPA in patients with inoperable CTEPH are required.