Chronic thromboembolic pulmonary hypertension: Evaluation with 64-detector row CT versus digital substraction angiography

Imaging of chronic thromboembolic pulmonary hypertension before, during and after balloon pulmonary angioplasty

Balloon pulmonary angioplasty (BPA) has recently been elevated as a class I recommendation for the treatment of inoperable or residual chronic thromboembolic pulmonary hypertension (CTEPH). Proper patient selection, procedural safety, and post-procedural evaluation are crucial in the management of these patients, with imaging work-up playing a pivotal role. Understanding the diagnostic and therapeutic imaging algorithms of CTEPH, the imaging features of patients amenable to BPA, all imaging findings observed during and immediately after the procedure and the changes observed during the follow-up is crucial for all interventional radiologists involved in the care of patients with CTEPH. This article illustrates the imaging work-up of patients with CTEPH amenable to BPA, the imaging findings observed before, during and after BPA, and provides a detailed description of all imaging modalities available for CTEPH evaluation.

Chronic Thromboembolic Pulmonary Hypertension

This JAMA Insights discusses the symptoms, diagnosis, and treatment of chronic thromboembolic pulmonary hypertension.

Diagnostic accuracy of perfusion-weighted phase-resolved functional lung magnetic resonance imaging in patients with chronic pulmonary embolism

Purpose

This study aimed to evaluate the diagnostic performance of perfusion-weighted phase-resolved functional lung (PW-PREFUL) magnetic resonance imaging (MRI) in patients with chronic pulmonary embolism (CPE).

Materials and methods

This study included 86 patients with suspected chronic thromboembolic pulmonary hypertension (CTEPH), who underwent PREFUL MRI and ventilation/perfusion (V/Q) single-photon emission computed tomography/computed tomography (SPECT/CT). PREFUL MRI was performed at 1.5 T using a balanced steady-state free precession sequence during free breathing. Color-coded PW images and quantitative parameters were obtained by postprocessing. Meanwhile, V/Q SPECT/CT imaging was performed as a reference standard. Hypoperfused areas in the lungs were scored for each lobe and segment using V/Q SPECT/CT images and PW-PREFUL MR images, respectively. Normalized perfusion (QN) and perfusion defect percentage (QDP) were calculated for all slices. For intra- and interobserver variability, the MRI images were analyzed 2 months after the first analysis by the same radiologist and another radiologist (11 years of lung MRI experience) blinded to the results of the first reader.

Results

Of the 86 enrolled patients, 77 met the inclusion criteria (36 diagnosed with CPE using V/Q SPECT/CT and 41 diagnosed with non-CPE etiology). For the PW-PREFUL MRI, the sensitivity, specificity, accuracy, and positive and negative predictive values for the diagnosis of CPE were 97, 95, 96, 95, and 98% at the patient level; 91, 94, 93, 91, and 94% at the lobe level, and 85, 94, 92, 88, and 94% at the segment level, respectively. The detection of segmental and subsegmental hypoperfusion using PW-PREFUL MRI revealed a moderate agreement with V/Q SPECT/CT (κ = 0.65; 95% confidence interval: 0.61-0.68). The quantitative results indicated that the QN was lower in the CPE group than in the non-CPE group [median score (interquartile range, IQR) 6.3 (2.8-9.2) vs. 13.0 (8.8-16.7), p < 0.001], and the QDP was higher [median score (IQR) 33.8 (15.7-51.7) vs. 2.2 (1.4-2.9), p < 0.001].

Conclusion

PREFUL MRI could be an alternative test to detect CPE without requiring breath-hold, contrast agents, or ionizing radiation.

Update on the roles of imaging in the management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH), classified as group 4 pulmonary hypertension (PH), is caused by stenosis and obstruction of the pulmonary arteries by organized thrombi that are incompletely resolved after acute pulmonary embolism. The prognosis of patients with CTEPH is poor if untreated; however, in expert centers with multidisciplinary teams, a treatment strategy for CTEPH has been established, dramatically improving its prognosis. CTEPH is currently not a fatal disease and is the only curable form of PH. Despite these advances and the establishment of treatment approaches, early diagnosis is still challenging, especially for non-experts, for several reasons. One of the reasons for this is insufficient knowledge of the various diagnostic imaging modalities, which are essential in the clinical practice of CTEPH. Imaging modalities should detect the following pathological findings: lung perfusion defects, thromboembolic lesions in pulmonary arteries, and right ventricular remodeling and dysfunction. Perfusion lung scintigraphy and catheter angiography have long been considered gold standards for the detection of perfusion defects and assessment of vascular lesions, respectively. However, advances in imaging technology of computed tomography and magnetic resonance imaging have enabled the non-invasive detection of these abnormal findings in a single examination. Cardiac magnetic resonance (CMR) is the gold standard for evaluating the morphology and function of the right heart; however, state-of-the-art techniques in CMR allow the assessment of cardiac tissue characterization and hemodynamics in the pulmonary arteries. Comprehensive knowledge of the role of imaging in CTEPH enables appropriate use of imaging modalities and accurate image interpretation, resulting in early diagnosis, determination of treatment strategies, and appropriate evaluation of treatment efficacy. This review summarizes the current roles of imaging in the clinical practice for CTEPH, demonstrating the characteristic findings observed in each modality.

Chronic Thromboembolic Pulmonary Disease and Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) and chronic thromboembolic pulmonary disease (CTEPD) are two terms characterizing symptomatic patients with chronic thromboembolic occlusions of pulmonary arteries with or without pulmonary hypertension at rest. Their diagnosis follows evolving schemas that integrate technological advances of pivotal imaging modalities among which computed tomography angiography plays a major role. This review article summarizes the current knowledge on the natural history of acute pulmonary embolism and its evolution toward chronic pulmonary embolism, as well as the imaging clues, for the identification of chronically obstructed pulmonary arteries. The requirements for imaging at the time of therapeutic decisions are also described in the light of recent updates in the literature from multidisciplinary groups of experts. Because an early diagnosis of CTEPH remains a challenge for the medical community, several practical issues are included in this article with the objective of improving the knowledge and collaboration between radiologists and clinicians in service to the patient.

The diagnostic performance of CT pulmonary angiography in the detection of chronic thromboembolic pulmonary hypertension-systematic review and meta-analysis

OBJECTIVES

To examine the diagnostic performance of CT of the pulmonary artery (CTPA) as a potential first-choice imaging modality in patients with pulmonary arterial hypertension and suspected chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

A systematic review and meta-analysis were conducted in accordance with the PRISMA reporting checklist. Six scientific databases and registers (PubMed, EMBASE, Scopus, Web of Science, Cochrane, ClinicalTrials.gov ) were searched for studies evaluating the diagnostic performance of CTPA in suspected CTEPH in adult patients. Results were pooled separately for studies based on the evaluation of the pulmonary artery and those that relied solely on changes in parenchymal perfusion.

RESULTS

Ten single-center studies with 734 patients were eligible for pooling of the diagnostic performance of CTPA by evaluation of the pulmonary artery. The pooled sensitivity, specificity, PPV, NPV, accuracy, and diagnostic odds ratio (DOR) estimates for CTPA in the detection of CTEPH were 0.98, 0.99, 0.94, 1.00, 0.96, 0.96, and 292. Evaluation of perfusion changes yielded pooled estimates for sensitivity, specificity, PPV, NPV, accuracy, and DOR of 0.99, 0.84, 0.79, 0.98, 0.89, 0.89, and 98 across four studies with 278 patients. Scintigraphy, SPECT, digital subtraction angiography, right heart catheterization, pulmonary endarterectomy, and international guidelines were used to establish the diagnosis.

CONCLUSION

CTPA has high sensitivity and specificity in the detection of CTEPH when the examination is evaluated by expert radiologists. Evaluation of parenchymal perfusion alone is associated with slightly lower specificity. Further research is needed to determine the diagnostic performance of CTPA in excluding CTEPH in general radiology departments.

KEY POINTS

• CT pulmonary angiography (CTPA) is recommended in the diagnostic workup of chronic thromboembolic pulmonary hypertension (CTEPH). • CTPA has high sensitivity and specificity in the detection of CTEPH when evaluated by an expert radiologist. • Evaluation of changes in parenchymal perfusion alone is associated with slightly lower specificity. • Little is known about the diagnostic performance of CTPA in the detection of CTEPH in general radiology departments.

ACR Appropriateness Criteria® Suspected Pulmonary Hypertension: 2022 Update

Pulmonary hypertension may be idiopathic or related to a large variety of diseases. Various imaging examinations may be helpful in diagnosing and determining the etiology of pulmonary hypertension. Imaging examinations discussed in this document include chest radiography, ultrasound echocardiography, ventilation/perfusion scintigraphy, CT, MRI, right heart catheterization, and pulmonary angiography. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Evaluating cardiopulmonary function following acute pulmonary embolism

INTRODUCTION

Pulmonary embolism is a common cause of cardiopulmonary mortality and morbidity worldwide. Survivors of acute pulmonary embolism may experience dyspnea, report reduced exercise capacity, or develop overt pulmonary hypertension. Clinicians must be alert for these phenomena and appreciate the modalities and investigations available for evaluation.

AREAS COVERED

In this review, the current understanding of available contemporary imaging and physiologic modalities is discussed, based on available literature and professional society guidelines. The purpose of the review is to provide clinicians with an overview of these modalities, their strengths and disadvantages, and how and when these investigations can support the clinical work-up of patients post-pulmonary embolism.

EXPERT OPINION

Echocardiography is a first test in symptomatic patients post-pulmonary embolism, with ventilation/perfusion scanning vital to determination of whether there is chronic residual emboli. The role of computed tomography and magnetic resonance in assessing the pulmonary arterial tree in post-pulmonary embolism patients is evolving. Functional testing, in particular cardiopulmonary exercise testing, is emerging as an important modality to quantify and determine cause of functional limitation. It is possible that future investigations of the post-pulmonary embolism recovery period will better inform treatment decisions for acute pulmonary embolism patients.

Acute on Chronic Thromboembolic Pulmonary Hypertension: Case Series and Review of Management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a distinct form of precapillary pulmonary hypertension classified as group 4 by the World Symposium on Pulmonary Hypertension (WSPH) and should be excluded during an episode of acute pulmonary embolism (PE). Patients presenting to emergency departments with sudden onset of signs and symptoms of acute PE may already have a pre-existing CTEPH condition decompensated by the new PE episode. Identifying an underlying and undiagnosed CTEPH during acute PE, while challenging, is an important consideration as it will alter the patients’ acute and long-term management. Differential diagnosis and evaluation require an interdisciplinary expert team. Analysis of the clinical condition, the CT angiogram, and the hemodynamic situation are important considerations; patients with CTEPH usually have significantly higher sPAP at the time of index PE, which is unusual and unattainable in the context of acute PE and a naïve right ventricle. The imaging may reveal signs of chronic disease such as right ventricle hypertrophy bronchial collaterals and atypical morphology of the thrombus. There is no standard for the management of acute on chronic CTEPH. Herein, we provide a diagnostic and management algorithm informed by several case descriptions and a review of the literature.

Diagnosis of Chronic Thromboembolic Pulmonary Hypertension Using Quantitative Lung Perfusion Parameters Extracted From Dual-energy Computed Tomography Images

PURPOSE

To evaluate quantified iodine mapping parameters in dual-energy computed tomography in normal patients versus those with chronic thromboembolic pulmonary hypertension (CTEPH) with and without pulmonary thromboembolism.

MATERIALS AND METHODS

Using automatically quantified iodine mapping in dual-energy computed tomography, we evaluated lung relative average enhancement, standard deviation (SD), and the SD/lung relative average enhancement ratio. We compared the values for these parameters in normal patients versus those with CTEPH. We also performed a receiver operating characteristic curve analysis to determine the diagnostic cutoffs for the parameters.

RESULTS

Patients constituted 41 patients (10 male [24.4%] and 31 female [75.6%]; mean age [SD]: 70.0 y [13.3]) with CTEPH and 237 (92 male [38.8%] and 145 female [61.2%]; mean age [SD]: 65.9 y [15.9]) normal patients. We found significant differences in lung relative average enhancement (34.9±6.3 vs. 26.9±6.3; P <0.0001), SD (11.6±1.9 vs. 14.7±3.3; P <0.001), and the SD/lung relative average enhancement ratio (33.7±5.0 vs. 55.7±10.4; P <0.001) between the normal and CTEPH groups, respectively. The ROC analyses demonstrated high discriminatory power (area under the curve=0.99) for using the SD/lung relative average enhancement ratio to differentiate between patients in the normal group and CTEPH group. At a threshold for the area under the curve of 44.2, diagnostic sensitivity, specificity, positive predictive value, and negative predictive value for the ratio were 92.7%, 97.5%, 86.5%, and 98.7%, respectively.

CONCLUSIONS

Patients with CTEPH were well-discriminated from normal patients using the SD/lung relative average enhancement ratio.

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.

Incidence and predictors of chronic thromboembolic pulmonary hypertension following acute pulmonary embolism: An echocardiography guided approach

There is significant variability in the worldwide epidemiology of chronic thromboembolic pulmonary hypertension (CTEPH). We thereby aim to determine the incidence and predictors of CTEPH, following an episode of acute pulmonary embolism (PE), using non-invasive modalities. Patients with acute PE were prospectively followed-up and after receiving at least 3 months of effective anticoagulation, persistently symptomatic patients with echocardiographic evidence of persistent pulmonary hypertension, were investigated further for CTEPH. Incidence of CTEPH was 8.19%. Delayed presentation, higher pulmonary artery pressures at presentation and discharge, and greater thrombotic burden were significant predictors for the development of CTEPH following acute PE.

Chronic Thromboembolic Pulmonary Hypertension: A Comprehensive Review and Multidisciplinary Approach to Surgical Treatment

Chronic thromboembolic pulmonary hypertension (CTEPH) is an underdiagnosed and undertreated sequelae of acute pulmonary embolism. In this comprehensive review, we provide an introductory overview of CTEPH, highlight recent advances in its diagnostic imaging, and describe the surgical technique for pulmonary thromboendarterectomy (PTE), the only established curative treatment for CTEPH. We also discuss the emerging role of balloon pulmonary angioplasty, both independently and combined with PTE, for patients with inoperable, residual, or refractory pulmonary hypertension post PTE. Finally, we stress the importance of a specialized multidisciplinary team approach to CTEPH patient care and share our approach to optimizing care for these patients.

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.

Incidence of chronic thromboembolic pulmonary hypertension in Taiwan

BACKGROUND

The diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) is complex, and the modality of treatment is surgery and targeted medication. Patients with CTEPH could have a poor prognosis if their diagnosis or treatment is delayed. The incidence of CTEPH and its clinical features are largely unknown in Taiwan, even among other Asian populations. In this study, we aimed to investigate the geodemographics of CTEPH in Taiwan and describe the practical management and treatment outcomes in patients with CTEPH.

METHODS

This study retrospectively enrolled patients in the Taiwan cohort - Registry of CTEPH. The study was conducted over 2 years inclusive of follow-up. The enrolment criteria depended on the current global guideline.

RESULTS

From January 2018 to March 2020, 107 CTEPH patients enrolled in the Taiwan registry. All patients received right heart catheterisation examinations. The overall median age was 61.4 ± 16.5 years, and the cohort was dominated by female patients (75/107). Risk factors included pulmonary embolism (81.3%), deep vein thrombosis (22.4%), and previous major surgery (20.6%). Twenty-one (19.6%) patients underwent pulmonary endarterectomy operation alone, and 38 (35.5%) patients underwent balloon pulmonary angioplasty alone.

CONCLUSION

To our knowledge, this is the first national cohort study that demonstrated the raw CTEPH incidence in Taiwan. It also showed the CTEPH incidence between male and female patients in the Asian population was different from the Caucasian population.

Optimizing the diagnosis and assessment of chronic thromboembolic pulmonary hypertension with advancing imaging modalities

Imaging is key to nearly all aspects of chronic thromboembolic pulmonary hypertension including management for screening, assessing eligibility for pulmonary endarterectomy, and post-operative follow-up. While ventilation/perfusion scintigraphy, the gold standard technique for chronic thromboembolic pulmonary hypertension screening, can have excellent sensitivity, it can be confounded by other etiologies of pulmonary malperfusion, and does not provide structural information to guide operability assessment. Conventional computed tomography pulmonary angiography has high specificity, though findings of chronic thromboembolic pulmonary hypertension can be visually subtle and unrecognized. In addition, computed tomography pulmonary angiography can provide morphologic information to aid in pre-operative workup and assessment of other structural abnormalities. Advances in computed tomography imaging techniques, including dual-energy computed tomography and spectral-detector computed tomography, allow for improved sensitivity and specificity in detecting chronic thromboembolic pulmonary hypertension, comparable to that of ventilation/perfusion scans. Furthermore, these advanced computed tomography techniques, compared with conventional computed tomography, provide additional physiologic data from perfused blood volume maps and improved resolution to better visualize distal chronic thromboembolic pulmonary hypertension, an important consideration for balloon pulmonary angioplasty for inoperable patients. Electrocardiogram-synchronized techniques in electrocardiogram-gated computed tomography can also show further information regarding right ventricular function and structure. While the standard of care in the workup of chronic thromboembolic pulmonary hypertension includes a ventilation/perfusion scan, computed tomography pulmonary angiography, direct catheter angiography, echocardiogram, and coronary angiogram, in the future an electrocardiogram-gated dual-energy computed tomography angiography scan may enable a "one-stop" imaging study to guide diagnosis, operability assessment, and treatment decisions with less radiation exposure and cost than traditional chronic thromboembolic pulmonary hypertension imaging modalities.

Chronic Thromboembolic Pulmonary Hypertension: the Bedside

PURPOSE OF REVIEW

Chronic thromboembolic pulmonary hypertension (CTEPH), included in group 4 PH, is an uncommon complication of acute pulmonary embolism (PE), in which emboli in the pulmonary vasculature do not resolve but rather form into an organized scar-like obstruction which can result in right ventricular (RV) failure. Here we provide an overview of current diagnosis and management of CTEPH.

RECENT FINDINGS

CTEPH management is complex with treatments that range from surgery, percutaneous interventions, to medical therapies. Current CTEPH medical therapies have largely been repurposed from pulmonary arterial hypertension (PAH). The diagnosis of CTEPH can be challenging, requiring a multimodality approach to differentiate from disease mimics. While these treatments improve symptoms, they may not reverse the underlying pathology of CTEPH.

Feasibility of a Noninvasive Operability Assessment in Chronic Thromboembolic Pulmonary Hypertension under Real-World Practice

This study aimed to evaluate the feasibility of a noninvasive operability assessment of chronic thromboembolic pulmonary hypertension (CTEPH) based on multidetector computed tomographic angiography (MCTA). Up to 176 patients were evaluated from January 2016 to April 2018. Throughout the first phase, the initial surgical decision was made based on MCTA with further analysis of pulmonary angiography (PA) in order to evaluate in which cases the initial decision was not modified by PA. During the second phase, PA was limited to patients judged inoperable based on MCTA or those whose assessment was not possible. Patients deemed operable (50%) based on MCTA along the first phase had been adequately classified, as PA did not modify the initial decision in all but one patient. Comparable results were obtained throughout the implementation phase. Regarding operated patients, the decision of operability was based solely on MCTA in 94% of those with level I disease, in 75% with level II, and 54% with level III. This approach enabled shorter periods of time to complete surgical assessment and the avoidance of PA-related morbidity. Baseline parameters, postoperative measures, and survival rates at 1 year after surgery were comparable in both phases. Noninvasive operability assessment is feasible in a subset of CTEPH patients and optimizes surgical candidacy evaluation.

The role of cardiac imaging in the management of non-ischemic cardiovascular diseases in human immunodeficiency virus infection

Infection with human immunodeficiency virus (HIV) has become the pandemic of the new century. About 36.9 million people are living with HIV worldwide. The introduction of antiretroviral therapy in 1996 has dramatically changed the global landscape of HIV care, resulting in significantly improved survival and changing HIV to a chronic disease. With near-normal life expectancy, contemporary cardiac care faces multiple challenges of cardiovascular diseases, disorders specific to HIV/AIDS, and those related to aging and higher prevalence of traditional risk factors. Non-ischemic cardiovascular diseases are major components of cardiovascular morbidity and mortality in HIV/AIDS. Non-invasive cardiac imaging plays a pivotal role in the management of these diseases. This review summarizes the non-ischemic presentation of the HIV cardiovascular spectrum focusing on the role of cardiac imaging in the management of these disorders.

Comparison of V/Q SPECT and CT Angiography for the Diagnosis of Chronic Thromboembolic Pulmonary Hypertension

Background Accurate methods for identifying obstructions in both large and small vessels are crucial for diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). Purpose To compare the performance of ventilation-perfusion (V/Q) scanning, V/Q SPECT, and CT pulmonary angiography (PA) in CTEPH by using digital subtraction PA as the reference standard. Materials and Methods This prospective study was conducted from January 2016 to January 2018. A total of 229 participants suspected of having CTEPH were evaluated with V/Q SPECT, V/Q planar scintigraphy, CT PA, and digital subtraction PA. Participants underwent all four procedures within 1 week. Differences in the diagnostic performance of V/Q SPECT, V/Q planar scintigraphy, and CT PA were evaluated with areas under the curve receiver operator curve, the McNemar test, and generalized estimating equations analysis. Results A total of 150 participants (mean age, 42 years ± 15 [standard deviation]; 99 women) were enrolled. Digital subtraction PA assessments confirmed CTEPH in 51 participants and indicated that 602 of 1020 lung segments (20 segments per participant) were obstructed. The three imaging methods showed high sensitivity (V/Q SPECT, 98%; V/Q planar scintigraphy, 98%; CT PA, 94%) and specificity (V/Q SPECT, 89%; V/Q planar scintigraphy, 91%; CT PA, 96%) (all P > .05). However, both V/Q scanning techniques were more sensitive (V/Q SPECT: 85%, P < .001 vs CT PA: 67%; V/Q planar scintigraphy: 83%, P < .001 vs CT PA: 67%), and less specific (V/Q planar scintigraphy: 51%, P = .03 vs CT PA: 60%; V/Q SPECT: 42%, P < .01 vs CT PA: 60%) than was CT PA for segmental analysis. Areas under the curve for CT PA, V/Q planar scintigraphy, and V/Q SPECT were 0.95, 0.95, and 0.94, respectively (all P > .05), for individual analysis, and 0.64, 0.67, and 0.64, respectively, by segment (V/Q planar scintigraphy vs V/Q SPECT, P = .02; V/Q planar scintigraphy vs CT PA, P = .08; V/Q SPECT vs CT PA, P = .94). Conclusion Ventilation-perfusion scanning was more sensitive and less specific than was CT pulmonary angiography for detecting vascular obstructions at the segmental pulmonary arterial level. © RSNA, 2020 See also the editorial by Swift and Rajaram in this issue.

Chronic thromboembolic pulmonary hypertension - still evolving

Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the leading causes of severe pulmonary hypertension (PH). The disease is still underdiagnosed, and the true prevalence is unknown. CTEPH is characterized by intraluminal non-resolving thrombus organization and fibrous stenosis, or complete obliteration of pulmonary arteries, promoted by progressive remodeling of the pulmonary vasculature. One consequence of this is an increase in pulmonary vascular resistance and pressure, resulting in PH and progressive right heart failure, leading to death if left untreated.

Endovascular disobliteration by pulmonary endarterectomy (PEA) is the preferred treatment for CTEPH patients. PEA surgery is the only technique that can potentially cure CTEPH disease, especially in patients with fresh or organized thrombi of the proximal branches of pulmonary arteries. However, not all patients are eligible for PEA surgery. Recent research has provided evidence suggesting balloon pulmonary angioplasty (BPA) and targeted medical therapy as additional promising available treatments options for inoperable CTEPH and recurrent/persistent PH after PEA surgery.

Studies on BPA have shown it to improve pulmonary hemodynamics, symptoms, exercise capacity and RV function in inoperable CTEPH. Subsequently, BPA has developed into an essential component of the modern era of CTEPH treatment. Large randomized controlled trials have demonstrated varying significant improvements with targeted medical therapy in technically inoperable CTEPH patients. Thus, treatment of CTEPH requires a comprehensive multidisciplinary assessment, including an experienced PEA surgeon, PH specialist, BPA interventionist and CTEPH-trained radiologist at expert centers. In this comprehensive review, we address the latest developments in the fast-evolving field of CTEPH. These include advancements in imaging modalities and developments in operative and interventional techniques, which have widened the range of patients who may benefit from these procedures. The efficacy and safety of targeted medical therapies in CTEPH patients are also discussed. As the treatment options for CTEPH improve, hybrid management involving multiple treatments in the same patient may become a viable option in the near future.

The changing face of pulmonary hypertension diagnosis: a historical perspective on the influence of diagnostics and biomarkers

Pulmonary hypertension is a complex, multifactorial disease that results in right heart failure and premature death. Since the initial reports of pulmonary hypertension in the late 1800s, the diagnosis of pulmonary hypertension has evolved with respect to its definition, screening tools, and diagnostic techniques. This historical perspective traces the earliest roots of pulmonary hypertension detection and diagnosis through to the current recommendations for classification. We highlight the diagnostic tools used in the past and present, and end with a focus on the future directions of early detection. Early detection of pulmonary hypertension and pulmonary arterial hypertension and the proper determination of etiology are vital for the early therapeutic intervention that can prolong life expectancy and improve quality of life. The search for a non-invasive screening tool for the identification and classification of pulmonary hypertension is ongoing, and we discuss the role of animal models of the disease in this search.

Assessing pulmonary hypertension in COPD. Is there a role for computed tomography?

Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD) and is associated with increased morbidity and mortality. Reference standard method to diagnose PH is right heart catheterization. Several non-invasive imaging techniques have been employed in the detection of PH. Among them, computed tomography (CT) is the most commonly used for phenotyping and detecting complications of COPD. Several CT findings have also been described in patients with severe PH. Nevertheless, CT analysis is currently based on visual findings which can lead to reproducibility failure. Therefore, there is a need for quantification in order to assess objective criteria. In this review, progresses in automated analyses of CT parameters and their values in predicting PH and COPD outcomes are presented.

Multimodality cardiovascular imaging in pulmonary embolism

Acute pulmonary embolism (APE) is one of the leading causes of cardiovascular (CV) morbidity and mortality. To select appropriate therapeutic strategy and/or to minimize the mortality and morbidity, rapid and correct identification of life-threatening APE is very important. Also, right ventricular (RV) failure usually precedes acute hemodynamic compromise or death, and thus the identification of RV failure is another important step in risk stratification or treatment of APE. With advances in diagnosis and treatment, the prognosis of APE has been dramatically improving in most cases, but inadequate therapy or recurrent episodes of pulmonary embolism (PE) may result in negative outcomes or, so called, chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a condition characterized by remaining chronic thromboembolic material in the pulmonary vasculature and subsequent chronic pulmonary hypertension. Various imaging modalities include chest computed tomography pulmonary angiography (CTPA), echocardiography, magnetic resonance imaging, and nuclear imaging and each are used for the assessment of varying status of PE. Assessment of thromboembolic burden by chest CTPA is the first step in the diagnosis of PE. Hemodynamic assessment can be achieved by echocardiography and also by chest CTPA. Nuclear imaging is useful in discriminating CTEPH from APE. Better perspectives on diagnosis, risk stratification and decision making in PE can be provided by combining multimodality CV imaging. Here, the advantages or pitfalls of each imaging modality in diagnosis, risk stratification, or management of PE will be discussed.

Evaluation and classification of pulmonary arterial hypertension

In early 2019, the 6th World Symposium on Pulmonary Hypertension (WSPH) released an updated document highlighting the advances in the last five years. During the quinquennial event many experts worked together to suggest new changes in the disease diagnosis and management. Since inception of the WSPH in 1973, this is the first time when the hemodynamic definition of pulmonary hypertension (PH) has been updated. These proceedings have re-defined the different hemodynamic types of PH that occur with the left heart disease along with introduction to the genetic testing as part of pulmonary arterial hypertension (PAH) evaluation. Objective of this review is to highlight the evaluation and diagnosis of PAH based on the proceedings of the 6th WSPH. Accurate early diagnosis and subsequent management of PH is necessary, as despite of treatment advances, survival remains suboptimal.

Chronic thromboembolic pulmonary hypertension (CTEPH): what do we know about it? A comprehensive review of the literature

: Chronic thromboembolic disease (CTED), especially when associated with pulmonary hypertension (CTEPH), is a fearsome and under-diagnosed but potentially curable complication of pulmonary embolism, thanks to recent therapeutic options. Aspecific symptoms and signs make its diagnosis challenging, requiring clinicians to be ready to suspect its presence in patients with dyspnea of unknown origin or persistent symptoms after acute pulmonary embolism. The aim of this review is to provide an update to the general practitioner or the specialist physician on the state of the art regarding the epidemiology, pathophysiology and clinical management of chronic thromboembolic syndromes.

State of the art: utility of multi-energy CT in the evaluation of pulmonary vasculature

Multi-energy computed tomography (MECT) refers to acquisition of CT data at multiple energy levels (typically two levels) using different technologies such as dual-source, dual-layer and rapid tube voltage switching. In addition to conventional/routine diagnostic images, MECT provides additional image sets including iodine maps, virtual non-contrast images, and virtual monoenergetic images. These image sets provide tissue/material characterization beyond what is possible with conventional CT. MECT provides invaluable additional information in the evaluation of pulmonary vasculature, primarily by the assessment of pulmonary perfusion. This functional information provided by the MECT is complementary to the morphological information from a conventional CT angiography. In this article, we review the technique and applications of MECT in the evaluation of pulmonary vasculature.

EXPRESS: Statement on imaging and pulmonary hypertension from the Pulmonary Vascular Research Institute (PVRI)

Pulmonary hypertension (PH) is highly heterogeneous and despite treatment advances it remains a life-shortening condition. There have been significant advances in imaging technologies, but despite evidence of their potential clinical utility, practice remains variable, dependent in part on imaging availability and expertise. This statement summarizes current and emerging imaging modalities and their potential role in the diagnosis and assessment of suspected PH. It also includes a review of commonly encountered clinical and radiological scenarios, and imaging and modeling-based biomarkers. An expert panel was formed including clinicians, radiologists, imaging scientists, and computational modelers. Section editors generated a series of summary statements based on a review of the literature and professional experience and, following consensus review, a diagnostic algorithm and 55 statements were agreed. The diagnostic algorithm and summary statements emphasize the key role and added value of imaging in the diagnosis and assessment of PH and highlight areas requiring further research.

Non-invasive Multimodality Cardiovascular Imaging of the Right Heart and Pulmonary Circulation in Pulmonary Hypertension

Pulmonary hypertension (PH) is defined as resting mean pulmonary arterial pressure (mPAP) ≥25 millimeters of mercury (mmHg) via right heart (RH) catheterization (RHC), where increased afterload in the pulmonary arterial vasculature leads to alterations in RH structure and function. Mortality rates have remained high despite therapy, however non-invasive imaging holds the potential to expedite diagnosis and lead to earlier initiation of treatment, with the hope of improving prognosis. While historically the right ventricle (RV) had been considered a passive chamber with minimal role in the overall function of the heart, in recent years in the evaluation of PH and RH failure the anatomical and functional assessment of the RV has received increased attention regarding its performance and its relationship to other structures in the RH-pulmonary circulation. Today, the RV is the key determinant of patient survival. This review provides an overview and summary of non-invasive imaging methods to assess RV structure, function, flow, and tissue characterization in the setting of imaging's contribution to the diagnostic, severity stratification, prognostic risk, response of treatment management, and disease surveillance implications of PH's impact on RH dysfunction and clinical RH failure.

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.

Current and emerging imaging techniques in the diagnosis and assessment of pulmonary hypertension

INTRODUCTION

Pulmonary hypertension (PH) is a challenging condition to diagnose and treat. Over the last two decades, there have been significant advances in therapeutic approaches and imaging technologies. Current guidelines emphasize the importance of cardiac catheterization; however, the increasing availability of non-invasive imaging has the potential to improve diagnostic rates, whilst providing additional information on patient phenotypes. Areas covered: This review discusses the role of imaging in the diagnosis, prognostic assessment and follow-up of patients with PH. Imaging methods, ranging from established investigations (chest radiography, echocardiography, nuclear medicine and computerized tomography (CT)), to emerging modalities (dual energy CT, magnetic resonance imaging (MRI), optical coherence tomography and positron emission tomography (PET)) are reviewed. The value and limitations of the clinical utility of these imaging modalities and their potential clinical application are reviewed. Expert commentary: Imaging plays a key role in the diagnosis and classification of pulmonary hypertension. It also provides valuable prognostic information and emerging evidence supports a role for serial assessments. The authors anticipate an increasing role for imaging in the pulmonary hypertension clinic. This will reduce the need for invasive investigations, whilst providing valuable insights that will improve our understanding of disease facilitate a more targeted approach to treatment.

Acute and chronic pulmonary embolism: the role of the pulmonary embolism response team

PURPOSE OF REVIEW

Acute pulmonary embolism is a life-threatening condition that can lead to both acute and long-term morbidity and mortality. Patients with acute pulmonary embolism are at risk for significant complications including the development of chronic pulmonary embolism and chronic thromboembolic pulmonary hypertension. This review will describe the rationale for and structure of pulmonary embolism response teams, with a focus on the recognition and treatment of patients with persistent morbidity following pulmonary embolism.

RECENT FINDINGS

For patients with intermediate and high-risk pulmonary embolism, a myriad of treatment options exist, ranging from anticoagulation alone to surgical embolectomy and hemodynamic support with extracorporeal membrane oxygenation. Optimizing treatment for these patients requires rapid assessment and multidisciplinary cooperation. Over the last five years, the pulmonary embolism response team has emerged as a mechanism to facilitate this care.

SUMMARY

Pulmonary embolism response teams can streamline and expedite care for patients with intermediate and high-risk pulmonary embolism. However, the care for patients with acute pulmonary embolism does not end at hospital discharge. It is essential to ensure adequate follow-up and identify patients with persistent symptoms and impaired quality of life, particularly those who may have symptomatic chronic pulmonary embolism or chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension from the perspective of patients with pulmonary embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but feared long-term complication of acute pulmonary embolism (PE), although CTEPH may occur in patients with no history of symptomatic venous thromboembolism. It represents the most severe presentation of the so-called 'post-PE syndrome', a phenomenon of permanent functional limitations after PE caused by deconditioning after PE or ventilatory or circulatory impairment as a result of unresolved pulmonary artery thrombi. Because the post-PE syndrome may occur in up to 50% of PE survivors, and CTEPH tends to have an insidious and non-specific clinical presentation, CTEPH is often not diagnosed or diagnosed after a very long delay. Once the diagnosis is confirmed, the treatment of choice is pulmonary endarterectomy which effectively lowers the pulmonary vascular resistance and normalizes resting pulmonary artery pressures, leading to recovery of the right ventricle. When pulmonary endarterectomy is not technically feasible, balloon pulmonary angioplasty may be a potential acceptable alternative. Also, medical treatment may help to improve patient's symptoms and hemodynamics. Current studies are focusing on strategies for earlier CTEPH diagnosis after acute PE, as well as the most optimal treatment of inoperable patients. This review will focus on the epidemiology, risk factors, diagnosis and treatment of CTEPH from the perspective of the PE patient.

Chronic pulmonary embolism: diagnosis

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of venous thromboembolic disease. Differently from other causes of pulmonary hypertension, CTEPH is potentially curable with surgery (thromboendarterectomy) or balloon pulmonary angioplasty. Imaging plays a central role in CTEPH diagnosis. The combination of techniques such as lung scintigraphy, computed tomography and magnetic resonance angiography provides non-invasive anatomic and functional information. Conventional pulmonary angiography (CPA) with right heart catheterization (RHC) is considered the gold standard method for diagnosing CTEPH. In this review, we discuss the utility of these imaging techniques in the diagnosis of CTEPH.

ACR Appropriateness Criteria® Suspected Pulmonary Hypertension

Pulmonary hypertension may be idiopathic or related to a large variety of diseases. Various imaging examinations that may be helpful in diagnosing and determining the etiology of pulmonary hypertension are discussed. Imaging examinations that may aid in the diagnosis of pulmonary hypertension include chest radiography, ultrasound echocardiography, ventilation/perfusion scans, CT, MRI, right heart catheterization, pulmonary angiography, and fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Diagnostic Evaluation of Chronic Thromboembolic Pulmonary Hypertension

Pulmonary hypertension is defined by a mean pulmonary artery pressure greater than 25 mm Hg. Chronic thromboembolic pulmonary hypertension (CTEPH) is defined as pulmonary hypertension in the presence of an organized thrombus within the pulmonary vascular bed that persists at least 3 months after the onset of anticoagulant therapy. Because CTEPH is potentially curable by surgical endarterectomy, correct identification of patients with this form of pulmonary hypertension and an accurate assessment of surgical candidacy are essential to provide optimal care. Patients most commonly present with symptoms of exertional dyspnea and otherwise unexplained decline in exercise capacity. Atypical chest pain, a nonproductive cough, and episodic hemoptysis are observed less frequently. With more advanced disease, patients often develop symptoms suggestive of right ventricular compromise. Physical examination findings are minimal early in the course of this disease, but as pulmonary hypertension progresses, may include nonspecific finding of right ventricular failure, such as a tricuspid regurgitation murmur, pedal edema, and jugular venous distention. Chest radiographs may suggest pulmonary hypertension, but are neither sensitive nor specific for the diagnosis. Radioisotopic ventilation-perfusion scanning is sensitive for detecting CTEPH, making it a valuable screening study. Conventional catheter-based pulmonary angiography retains an important role in establishing the presence and extent of chronic thromboembolic disease. However, computed tomographic and magnetic resonance imaging are playing a growing diagnostic role. Innovative technologies such as dual-energy computed tomography, dynamic contrast-enhanced magnetic resonance imaging, and optical coherence tomography show promise for contributing diagnostic information and assisting in the preoperative characterization of patients with CTEPH.

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.

Modern diagnosis of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) should be suspected in patients presenting persistent dyspnea three months after a pulmonary embolism or in patients presenting with acute pulmonary embolism and suggestive images on the CT-scan. For these patients, a specific diagnostic work-up should be performed. First step consists of the ventilation/perfusion (V/Q) scan which is a good screening test due to its high sensitivity and high negative predictive value. Pulmonary angiography remains the gold standard approach for the confirmation of the diagnosis and pre-surgical evaluation of CTEPH. New emerging technologies such as Dual-Energy Computed Tomography angiography (DECT) and Computed Tomography angiography (CTA) are developing and broadly available. These non invasive methods provide diagnostic information similar to conventional pulmonary angiography and surgical operability information. They are to be considered as an alternative in the diagnostic approach of patients with CTEPH as presented in the ESC/ERS guidelines. Haemodynamic measurement whiles exercising during right heart catheterization may improve diagnostic sensitivity of CTEPH and could therefore be used as a diagnostic test in patient with normal haemodynamic at rest.

Chronic Thromboembolic Pulmonary Hypertension: Pearls and Pitfalls of Diagnosis

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by chronic obstruction of major pulmonary arteries by organized thromboembolic material. Untreated CTEPH can result in pulmonary hypertension and eventually right heart failure, yet it is the only form of pulmonary hypertension that is potentially curable with surgical or catheter-based intervention. While early diagnosis is key to increasing the likelihood of successful treatment, CTEPH remains largely underdiagnosed. This article reviews the role of echocardiogram, ventilation/perfusion scan, and other available modalities in the diagnosis of CTEPH.

[Subtraction CT angiopulmonographic assessment of the vascular bed and lung perfusion in patients with chronic thromboembolic pulmonary hypertension: A pilot study]

AIM

To evaluate the vascular bed and lung perfusion in patients with chronic thromboembolic pulmonary hypertension (CTEPH) by computed tomography (CT) and to compare the severity of pulmonary arterial (PA) thrombotic lesions concurrent with parenchymal perfusion disorders with angiopulmonographic findings and clinical and hemodynamic characteristics.

SUBJECTS AND METHODS

In the period from November 2015 to May 2016, 22 patients (7 men, 15 women) aged 27 to 67 years with a verified diagnosis of CTEPH were examined using an Aquilion ONE VISION Edition 640 (Toshiba Medical Systems, Japan) CT scanner with a 320-row detector. Perfusion defect in this study was evaluated with the new software allowing one to combine contrast and contrast-free images by a subtraction method. CT data analysis included visual assessment of the vascular bed and lung parenchyma and quantitative assessment with perfusion map construction and semi-automatic determination of the obstruction index (OI) and perfusion defect index (PDI). OI was compared with PDI and mean LA pressure according to the data of right heart catheterization and 6-minute walk test.

RESULTS

A statistically significant correlation was found between OI and PDI in patients with CTEPH (Pearson r=0.56; p=0.0065). There were no relationships between mean LA pressure and vascular perfusion indices (OI and PDI) or between vascular perfusion parameters and 6-minute walk test results.

CONCLUSION

CT angiopulmonography in conjunction with pulmonary perfusion assessment (within one study) allows evaluation of the severity of vascular lesions and perfusion disorders and determination of the efficiency of treatment in patients with CTEPH.

ANMCO Position Paper: long-term follow-up of patients with pulmonary thromboembolism

Venous thromboembolism (VTE), including pulmonary embolism and deep venous thrombosis, is the third most common cause of cardiovascular death. The management of the acute phase of VTE has already been described in several guidelines. However, the management of the follow-up (FU) of these patients has been poorly defined. This consensus document, created by the Italian cardiologists, wants to clarify this issue using the currently available evidence in VTE. Clinical and instrumental data acquired during the acute phase of the disease are the cornerstone for planning the FU. Acquired or congenital thrombophilic disorders could be identified in apparently unprovoked VTE during the FU. In other cases, an occult cancer could be discovered after a VTE. The main targets of the post-acute management are to prevent recurrence of VTE and to identify the patients who can develop a chronic thromboembolic pulmonary hypertension. Knowledge of pathophysiology and therapeutic approaches is fundamental to decide the most appropriate long-term treatment. Moreover, prognostic stratification during the FU should be constantly updated on the basis of the new evidence acquired. Currently, the cornerstone of VTE treatment is represented by both the oral and the parenteral anticoagulation. Novel oral anticoagulants should be an interesting alternative in the long-term 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.

Chronic Thromboembolic Pulmonary Hypertension: the End Result of Pulmonary Embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) occurs when a pulmonary embolism fails to undergo complete thrombolysis leading to vascular occlusion and pulmonary hypertension. Despite the fact that CTEPH is a potential consequence of pulmonary embolism, diagnosis requires a high degree of vigilance as many patients will not have a history of thromboembolic disease. The ventilation perfusion scan is used to evaluate for the possibility of CTEPH although right heart catheterization and pulmonary artery angiogram are needed to confirm the diagnosis. Pulmonary thromboendarterectomy is the first-line treatment for patients who are surgical candidates. Recently, riociguat has been approved for patients with nonsurgical disease or residual pulmonary hypertension despite surgical intervention. This review describes the pathophysiology, risk factors, diagnosis, and management of CTEPH.