Angiopoietin 2 and hsCRP are associated with pulmonary hemodynamics and long-term mortality respectively in CTEPH-Results from a prospective discovery and validation biomarker study

INTRODUCTION

Chronic thromboembolic pulmonary hypertension (CTEPH) is an underdiagnosed disease of uncertain etiology. Altered endothelial homeostasis, defective angiogenesis and inflammation are implicated. Angiopoietin 2 (Ang2) impairs acute thrombus resolution and is associated with vasculopathy in idiopathic pulmonary arterial hypertension.

METHODS

We assessed circulating proteins associated with these processes in serum from patients with CTEPH (n = 71) before and after pulmonary endarterectomy (PEA), chronic thromboembolic pulmonary disease without pulmonary hypertension (CTEPD, n = 9) and healthy controls (n = 20) using Luminex multiplex arrays. Comparisons between groups were made using multivariable rank regression models. Ang2 and high-sensitivity C-reactive protein (hsCRP) were measured in a larger validation dataset (CTEPH = 277, CTEPD = 26). Cox proportional hazards models were used to identify markers predictive of survival.

RESULTS

In CTEPH patients, Ang2, interleukin (IL) 8, tumor necrosis factor α, and hsCRP were elevated compared to controls, while vascular endothelial growth factor (VEGF) c was lower (p < 0.05). Ang2 fell post-PEA (p < 0.05) and was associated with both pre- and post-PEA pulmonary hemodynamic variables and functional assessments (p < 0.05). In the validation dataset, Ang2 was significantly higher in CTEPH compared to CTEPD. Pre-operative hsCRP was an independent predictor of mortality.

CONCLUSIONS

We hypothesize that CTEPH patients have significant distal micro-vasculopathy and consequently high circulating Ang2. Patients with CTEPD without pulmonary hypertension have no discernible distal micro-vasculopathy and therefore have low circulating Ang2. This suggests Ang2 may be critical to CTEPH disease pathogenesis (impaired thrombus organization and disease severity).

Highlights from the International Chronic Thromboembolic Pulmonary Hypertension Congress 2021

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism. It is caused by persistent obstruction of pulmonary arteries by chronic organised fibrotic clots, despite adequate anticoagulation. The pulmonary hypertension is also caused by concomitant microvasculopathy which may progress without timely treatment. Timely and accurate diagnosis requires the combination of imaging and haemodynamic assessment. Optimal therapy should be individualised to each case and determined by an experienced multidisciplinary CTEPH team with the ability to offer all current treatment modalities. This report summarises current knowledge and presents key messages from the International CTEPH Conference, Bad Nauheim, Germany, 2021. Sessions were dedicated to 1) disease definition; 2) pathophysiology, including the impact of the hypertrophied bronchial circulation, right ventricle (dys)function, genetics and inflammation; 3) diagnosis, early after acute pulmonary embolism, using computed tomography and perfusion techniques, and supporting the selection of appropriate therapies; 4) surgical treatment, pulmonary endarterectomy for proximal and distal disease, and peri-operative management; 5) percutaneous approach or balloon pulmonary angioplasty, techniques and complications; and 6) medical treatment, including anticoagulation and pulmonary hypertension drugs, and in combination with interventional treatments. Chronic thromboembolic pulmonary disease without pulmonary hypertension is also discussed in terms of its diagnostic and therapeutic aspects.

Acute lung injury after balloon pulmonary angioplasty results in a similar haemodynamic response and possible clinical advantage at follow-up

Acute lung injury (ALI) is a common but poorly defined and understood complication of balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH). Little data are available on the medium term clinical outcomes of BPA complicated by ALI. We analyzed per-procedure data from 282 procedures in 109 patients and per-patient data from 85 patients. Serial right heart catheterization at baseline, after each BPA and at 3-month follow-up measured pulmonary vascular resistance (PVR), mean pulmonary artery pressure (mPAP), and cardiac output (CO). ALI (ALI+) was identified by chest radiography alone (ALI_r+) or in association with hypoxia clinically (ALI_cr+). Procedural predictors of ALI and patient outcomes at 3-months were compared no ALI (ALI-). ALI+ occurred in 17/282 (6.0%) procedures (ALI_cr+: 2.5%, ALI_r+: 3.5%). Prevailing haemodynamics (PVR: p < 0.01; mPAP: p < 0.05) at a procedural and patient level, as well as number of BPA sessions (p < 0.01), total number of vessels (p < 0.05), and occlusions (p < 0.05) treated at a patient level predicted ALI+. Those with ALI had greater percentage improvement in ΔCAMPHOR symptoms score (ALI+: -63.5 ± 35.7% (p < 0.05); ALI_cr+: -84.4 ± 14.5% (p < 0.01); ALI-: -27.2 ± 74.2%) and ΔNT-proBNP (ALI_cr+: -78.4 ± 11.9% (p < 0.01); ALI-: -42.9 ± 36.0%) at follow-up. There was no net significant difference in haemodynamic changes in ALI+ versus ALI- at follow-up. ALI is predicted by haemodynamic severity, number of vessels treated, number of BPA sessions, and treating occlusive disease. ALI in this cohort was associated with a clinical advantage at follow-up.

Vascular Thrombosis in Severe COVID-19 Requiring Extracorporeal Membrane Oxygenation: A Multicenter Study

OBJECTIVES

Coronavirus disease 2019 has been reported to be a prothrombotic condition; however, multicenter data comparing this with other viral pneumonias in those requiring extracorporeal membrane oxygenation are lacking. We conducted a multicenter study using whole-body CT to examine the prevalence, severity, and nature of vascular complications in coronavirus disease 2019 in comparison with patients with other viral pneumonias.

DESIGN

We analyzed whole-body CT scans for the presence of vascular thrombosis (defined as pulmonary artery thrombus, venous thrombus, systemic arterial thrombus, or end-organ infarct). The severity, distribution, and morphology of pulmonary artery thrombus were characterized. Competing risk cumulative incidence analysis was used to compare survival with discharge.

SETTING

Three centers of the English national extracorporeal membrane oxygenation service.

PATIENTS

Consecutive patients admitted with either coronavirus disease 2019 or noncoronavirus disease 2019 viral pneumonia admitted from January 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-hundred thirty-six patients (45.2 ± 10.6 yr old, 39/146 [27%] female) requiring extracorporeal membrane oxygenation support underwent whole-body CT scans at admission. Of these, 86 had coronavirus disease 2019 pneumonia, and 50 had noncoronavirus disease 2019 viral pneumonia. Vascular thrombosis was seen more often in patients with coronavirus disease 2019 (odds ratio, 12.9 [95% CI 4.5-36.8]). In those with coronavirus disease 2019, 57 (73%) demonstrated pulmonary artery thrombus or pulmonary perfusion defects. Eighty-two percent of thrombus exhibited emboli-like morphology. The location of pulmonary artery thrombus and parenchymal perfusion defects was only concordant in 30% of cases. The risk of mortality was higher in those with coronavirus disease 2019 compared with noncoronavirus disease 2019 pneumonia (χ2 = 3.94; p = 0.047). Mortality was no different in coronavirus disease 2019 patients with or without vascular thrombosis (χ2 = 0.44; p = 0.51).

CONCLUSIONS

In patients who received extracorporeal membrane oxygenation, coronavirus disease 2019 is associated with a higher prevalence of vascular thrombosis compared with noncoronavirus disease viral pneumonias. The pattern of pulmonary vascular changes suggests concurrent embolic disease and small vessel disease. Despite this, vascular thrombosis was not linked to poorer short-term prognosis in those with coronavirus disease 2019.

COVID-19 pneumonia imaging follow-up: when and how? A proposition from ESTI and ESR

Abstract

This document from the European Society of Thoracic Imaging (ESTI) and the European Society of Radiology (ESR) discusses the role of imaging in the long-term follow-up of COVID-19 patients, to define which patients may benefit from imaging, and what imaging modalities and protocols should be used. Insights into imaging features encountered on computed tomography (CT) scans and potential pitfalls are discussed and possible areas for future review and research are also included.

Key Points

• Post-COVID-19 pneumonia changes are mainly consistent with prior organizing pneumonia and are likely to disappear within 12 months of recovery from the acute infection in the majority of patients.

• At present, with the longest series of follow-up examinations reported not exceeding 12 months, the development of persistent or progressive fibrosis in at least some individuals cannot yet be excluded.

• Residual ground glass opacification may be associated with persisting bronchial dilatation and distortion, and might be termed “fibrotic-like changes” probably consistent with prior organizing pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08317-7.

Rising COVID-19 related acute pulmonary emboli but falling national chronic thromboembolic pulmonary hypertension referrals from a large national dataset

The average rate of new #CTEPH referrals has dropped by 32% in the UK during the pandemic, despite the high incidence of #COVID19 related pulmonary emboli. There have been no recorded new cases of CTEPH caused by COVID-19. A prospective study is underway. https://bit.ly/37msP2G.

Serial right heart catheter assessment between balloon pulmonary angioplasty sessions identify procedural factors that influence response to treatment

BACKGROUND

Balloon pulmonary angioplasty (BPA) is delivered as a series of treatments for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) however, there is little published data on the procedural determinants of outcome.

METHODS

Pre- and post-BPA clinical and hemodynamic data, as well as serial hemodynamic and procedural data at each BPA session were evaluated to determine patient and procedure-related factors that influence hemodynamic response.

RESULTS

Per procedure data from 210 procedures in 84 patients and per patient data from 182 procedures in 63 patients with completed treatment and 3-month follow-up were analyzed. A median of 3 (range 1-6) BPA procedures treating a median of 2 segments per procedure (range 1-3) were performed per patient with a median interval between procedures of 42 (range 5-491) days. Clinical outcome correlated with hemodynamic change (pulmonary vascular resistance [ΔPVR] vs Cambridge Pulmonary Hypertension Outcome Review [CAMPHOR] symptom score: p < 0.001, Pearson's r = 0.48, n = 49). Responders to BPA had more severe disease at baseline and 37.5 % of non-responders were post-PEA. There was a dose-response relationship between per procedure and total number of segments treated and hemodynamic improvement (ΔPVR: 1 segment: -0.9%, 2: -14.5%, 3 or more: -16.1%, p < 0.001). Treating totally occluded vessels had a greater hemodynamic effect (mean pulmonary artery pressure [ΔmPAP]: sessions with occlusion: -8.0%, without occlusion treated: -3.2%, p < 0.05) without an increased complication rate.

CONCLUSIONS

The magnitude of clinical benefit is related to the hemodynamic effect of BPA which in turn is related to the number of segments treated and lesion severity. Patients who were post-PEA were less likely to respond to BPA.

Balloon pulmonary angioplasty for inoperable chronic thromboembolic pulmonary hypertension: the UK experience

Objective

Inoperable chronic thromboembolic pulmonary hypertension (CTEPH) managed medically has a poor prognosis. Balloon pulmonary angioplasty (BPA) offers a new treatment for inoperable patients. The national BPA service for the UK opened in October 2015 and we now describe the treatment of our initial patient cohort.

Methods

Thirty consecutive, inoperable, anatomically suitable, symptomatic patients on stable medical therapy for CTEPH were identified and offered BPA. They initially underwent baseline investigations including Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) quality of life (QoL) questionnaire, cardiopulmonary exercise test, 6 min walk distance (6MWD), transthoracic echocardiography, N-terminal probrain natriuretic peptide (NT pro-BNP) and right heart catheterisation. Serial BPA sessions were then performed and after completion, the treatment effect was gauged by comparing the same investigations at 3 months follow-up.

Results

A median of 3 (IQR 1-6) BPA sessions per patient resulted in a significant improvement in functional status (WHO functional class ≥3: 24 vs 4, p<0.0001) and QoL (CAMPHOR symptom score: 8.7±5.4 vs 5.6±6.1, p=0.0005) with reductions in pulmonary pressures (mean pulmonary artery pressure: 44.7±11.0 vs 34.4±8.3 mm Hg, p<0.0001) and resistance (pulmonary vascular resistance: 663±281 vs 436±196 dyn.s.cm-5, p<0.0001). Exercise capacity improved (minute ventilation/carbon dioxide production: 55.3±12.2 vs 45.0±7.8, p=0.03 and 6MWD: 366±107 vs 440±94 m, p<0.0001) and there was reduction in right ventricular (RV) stretch (NT pro-BNP: 442 (IQR 168-1607) vs 202 (IQR 105-447) pg/mL, p<0.0001) and dimensions (mid RV diameter: 4.4±1.0 vs 3.8±0.7 cm, p=0.002). There were no deaths or life-threatening complications and the mild-moderate per-procedure complication rate was 10.5%.

Conclusions

BPA is safe and improves the functional status, QoL, pulmonary haemodynamics and RV dimensions of patients with inoperable CTEPH.

A multicenter study of anticoagulation in operable chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is an uncommon complication of acute pulmonary emboli necessitating lifelong anticoagulation. Despite this, few data exist on the safety and efficacy of vitamin K antagonists (VKAs) in CTEPH and none for direct oral anticoagulants (DOACs).

OBJECTIVES

To evaluate outcomes and complication rates in CTEPH following pulmonary endarterectomy (PEA) for individuals receiving VKAs or DOACs.

METHODS

Consecutive CTEPH patients undergoing PEA between 2007 and 2018 were included in a retrospective analysis. Postoperative outcomes, recurrent venous thromboembolism (VTE), and bleeding events were obtained from patient medical records.

RESULTS

Seven hundred ninety-four individuals were treated with VKAs and 206 with DOACs following PEA. Mean observation period was 612 (standard deviation: 702) days. Significant improvements in hemodynamics and functional status were observed in both groups following PEA (P < .001). Major bleeding events were equivalent (P = 1) in those treated with VKAs (0.67%/person-year) and DOACs (0.68%/person-year). The VTE recurrence was proportionately higher (P = .008) with DOACs (4.62%/person-year) than VKAs (0.76%/person-year), although survival did not differ.

CONCLUSIONS

Post-PEA functional and hemodynamic outcomes appear unaffected by anticoagulant choice. Bleeding events were similar, but recurrent VTE rates significantly higher in those receiving DOACs. Our study provides a strong rationale for prospective registry data and/or studies to evaluate the safety of DOACs in CTEPH.

The ADAMTS13-VWF axis is dysregulated in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an important consequence of pulmonary embolism that is associated with abnormalities in haemostasis. We investigated the ADAMTS13–von Willebrand factor (VWF) axis in CTEPH, including its relationship with disease severity, inflammation, ABO groups and ADAMTS13 genetic variants.

ADAMTS13 and VWF plasma antigen levels were measured in patients with CTEPH (n=208), chronic thromboembolic disease without pulmonary hypertension (CTED) (n=35), resolved pulmonary embolism (n=28), idiopathic pulmonary arterial hypertension (n=30) and healthy controls (n=68). CTEPH genetic ABO associations and protein quantitative trait loci were investigated. ADAMTS13–VWF axis abnormalities were assessed in CTEPH and healthy control subsets by measuring ADAMTS13 activity, D-dimers and VWF multimeric size.

Patients with CTEPH had decreased ADAMTS13 (adjusted β −23.4%, 95% CI −30.9– −15.1%, p<0.001) and increased VWF levels (β +75.5%, 95% CI 44.8–113%, p<0.001) compared to healthy controls. ADAMTS13 levels remained low after reversal of pulmonary hypertension by pulmonary endarterectomy surgery and were equally reduced in CTED. We identified a genetic variant near the ADAMTS13 gene associated with ADAMTS13 protein that accounted for ∼8% of the variation in levels.

The ADAMTS13–VWF axis is dysregulated in CTEPH. This is unrelated to pulmonary hypertension, disease severity or markers of systemic inflammation and implicates the ADAMTS13–VWF axis in CTEPH pathobiology.

The ADAMTS-13–VWF axis is dysregulated in chronic thromboembolism with and without pulmonary hypertension and is implicated in the pathogenesishttp://ow.ly/J9SC30nh5T0

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.

The impact of patient choice on survival in chronic thromboembolic pulmonary hypertension

Pulmonary endarterectomy (PEA) is the gold standard treatment for operable chronic thromboembolic pulmonary hypertension (CTEPH). However, a proportion of patients with operable disease decline surgery. There are currently no published data on this patient group. The aim of this study was to identify outcomes and prognostic factors in a large cohort of consecutive patients with CTEPH.Data were collected for consecutive, treatment-naive CTEPH patients at the Pulmonary Vascular Disease Unit of the Royal Hallamshire Hospital (Sheffield, UK) between 2001 and 2014.Of 550 CTEPH patients (mean±sd age 63±15 years, follow-up 4±3 years), 49% underwent surgery, 32% had technically operable disease and did not undergo surgery (including patient choice n=72 and unfit for surgery n=63), and 19% had inoperable disease due to disease distribution. The 5-year survival was superior in patients undergoing PEA (83%) versus technically operable disease who did not undergo surgery (53%) and inoperable due to disease distribution (59%) (p<0.001). Survival was superior in patients following PEA compared with those offered but declining surgery (55%) (p<0.001). In patients offered PEA, independent prognostic factors included mixed venous oxygen saturation, gas transfer and patient decision to proceed to surgery.Outcomes in CTEPH following PEA are excellent and superior to patients declining surgery, and strongly favour consideration of a surgical intervention in eligible patients.

Phenotypic Characterization of EIF2AK4 Mutation Carriers in a Large Cohort of Patients Diagnosed Clinically With Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare disease with an emerging genetic basis. Heterozygous mutations in the gene encoding the bone morphogenetic protein receptor type 2 (BMPR2) are the commonest genetic cause of PAH, whereas biallelic mutations in the eukaryotic translation initiation factor 2 alpha kinase 4 gene (EIF2AK4) are described in pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Here, we determine the frequency of these mutations and define the genotype-phenotype characteristics in a large cohort of patients diagnosed clinically with PAH.

METHODS

Whole-genome sequencing was performed on DNA from patients with idiopathic and heritable PAH and with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis recruited to the National Institute of Health Research BioResource-Rare Diseases study. Heterozygous variants in BMPR2 and biallelic EIF2AK4 variants with a minor allele frequency of <1:10 000 in control data sets and predicted to be deleterious (by combined annotation-dependent depletion, PolyPhen-2, and sorting intolerant from tolerant predictions) were identified as potentially causal. Phenotype data from the time of diagnosis were also captured.

RESULTS

Eight hundred sixty-four patients with idiopathic or heritable PAH and 16 with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis were recruited. Mutations in BMPR2 were identified in 130 patients (14.8%). Biallelic mutations in EIF2AK4 were identified in 5 patients with a clinical diagnosis of pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Furthermore, 9 patients with a clinical diagnosis of PAH carried biallelic EIF2AK4 mutations. These patients had a reduced transfer coefficient for carbon monoxide (Kco; 33% [interquartile range, 30%-35%] predicted) and younger age at diagnosis (29 years; interquartile range, 23-38 years) and more interlobular septal thickening and mediastinal lymphadenopathy on computed tomography of the chest compared with patients with PAH without EIF2AK4 mutations. However, radiological assessment alone could not accurately identify biallelic EIF2AK4 mutation carriers. Patients with PAH with biallelic EIF2AK4 mutations had a shorter survival.

CONCLUSIONS

Biallelic EIF2AK4 mutations are found in patients classified clinically as having idiopathic and heritable PAH. These patients cannot be identified reliably by computed tomography, but a low Kco and a young age at diagnosis suggests the underlying molecular diagnosis. Genetic testing can identify these misclassified patients, allowing appropriate management and early referral for lung transplantation.

The UK Lung Cancer Screening Trial: a pilot randomised controlled trial of low-dose computed tomography screening for the early detection of lung cancer

BACKGROUND

Lung cancer kills more people than any other cancer in the UK (5-year survival < 13%). Early diagnosis can save lives. The USA-based National Lung Cancer Screening Trial reported a 20% relative reduction in lung cancer mortality and 6.7% all-cause mortality in low-dose computed tomography (LDCT)-screened subjects.

OBJECTIVES

To (1) analyse LDCT lung cancer screening in a high-risk UK population, determine optimum recruitment, screening, reading and care pathway strategies; and (2) assess the psychological consequences and the health-economic implications of screening.

DESIGN

A pilot randomised controlled trial comparing intervention with usual care. A population-based risk questionnaire identified individuals who were at high risk of developing lung cancer (≥ 5% over 5 years).

SETTING

Thoracic centres with expertise in lung cancer imaging, respiratory medicine, pathology and surgery: Liverpool Heart & Chest Hospital, Merseyside, and Papworth Hospital, Cambridgeshire.

PARTICIPANTS

Individuals aged 50-75 years, at high risk of lung cancer, in the primary care trusts adjacent to the centres.

INTERVENTIONS

A thoracic LDCT scan. Follow-up computed tomography (CT) scans as per protocol. Referral to multidisciplinary team clinics was determined by nodule size criteria.

MAIN OUTCOME MEASURES

Population-based recruitment based on risk stratification; management of the trial through web-based database; optimal characteristics of CT scan readers (radiologists vs. radiographers); characterisation of CT-detected nodules utilising volumetric analysis; prevalence of lung cancer at baseline; sociodemographic factors affecting participation; psychosocial measures (cancer distress, anxiety, depression, decision satisfaction); and cost-effectiveness modelling.

RESULTS

A total of 247,354 individuals were approached to take part in the trial; 30.7% responded positively to the screening invitation. Recruitment of participants resulted in 2028 in the CT arm and 2027 in the control arm. A total of 1994 participants underwent CT scanning: 42 participants (2.1%) were diagnosed with lung cancer; 36 out of 42 (85.7%) of the screen-detected cancers were identified as stage 1 or 2, and 35 (83.3%) underwent surgical resection as their primary treatment. Lung cancer was more common in the lowest socioeconomic group. Short-term adverse psychosocial consequences were observed in participants who were randomised to the intervention arm and in those who had a major lung abnormality detected, but these differences were modest and temporary. Rollout of screening as a service or design of a full trial would need to address issues of outreach. The health-economic analysis suggests that the intervention could be cost-effective but this needs to be confirmed using data on actual lung cancer mortality.

CONCLUSIONS

The UK Lung Cancer Screening (UKLS) pilot was successfully undertaken with 4055 randomised individuals. The data from the UKLS provide evidence that adds to existing data to suggest that lung cancer screening in the UK could potentially be implemented in the 60-75 years age group, selected via the Liverpool Lung Project risk model version 2 and using CT volumetry-based management protocols.

FUTURE WORK

The UKLS data will be pooled with the NELSON (Nederlands Leuvens Longkanker Screenings Onderzoek: Dutch-Belgian Randomised Lung Cancer Screening Trial) and other European Union trials in 2017 which will provide European mortality and cost-effectiveness data. For now, there is a clear need for mortality results from other trials and further research to identify optimal methods of implementation and delivery. Strategies for increasing uptake and providing support for underserved groups will be key to implementation.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN78513845.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 40. See the NIHR Journals Library website for further project information.

Dynamic Risk Stratification of Patient Long-Term Outcome After Pulmonary Endarterectomy: Results From the United Kingdom National Cohort

BACKGROUND

Chronic thromboembolic pulmonary hypertension results from incomplete resolution of pulmonary emboli. Pulmonary endarterectomy (PEA) is potentially curative, but residual pulmonary hypertension following surgery is common and its impact on long-term outcome is poorly understood. We wanted to identify factors correlated with poor long-term outcome after surgery and specifically define clinically relevant residual pulmonary hypertension post-PEA.

METHODS AND RESULTS

Eight hundred eighty consecutive patients (mean age, 57 years) underwent PEA for chronic thromboembolic pulmonary hypertension. Patients routinely underwent detailed reassessment with right heart catheterization and noninvasive testing at 3 to 6 months and annually thereafter with discharge if they were clinically stable at 3 to 5 years and did not require pulmonary vasodilator therapy. Cox regressions were used for survival (time-to-event) analyses. Overall survival was 86%, 84%, 79%, and 72% at 1, 3, 5, and 10 years for the whole cohort and 91% and 90% at 1 and 3 years for the recent half of the cohort. The majority of patient deaths after the perioperative period were not attributable to right ventricular failure (chronic thromboembolic pulmonary hypertension). At reassessment, a mean pulmonary artery pressure of ≥30 mm Hg correlated with the initiation of pulmonary vasodilator therapy post-PEA. A mean pulmonary artery pressure of ≥38 mm Hg and pulmonary vascular resistance ≥425 dynes·s(-1)·cm(-5) at reassessment correlated with worse long-term survival.

CONCLUSIONS

Our data confirm excellent long-term survival and maintenance of good functional status post-PEA. Hemodynamic assessment 3 to 6 months and 12 months post-PEA allows stratification of patients at higher risk of dying of chronic thromboembolic pulmonary hypertension and identifies a level of residual pulmonary hypertension that may guide the long-term management of patients postsurgery.

Cardiothoracic manifestations of neuroendocrine tumours

Cardiothoracic neuroendocrine tumour (NET) manifestations encompass a vast disease spectrum. Pulmonary neuroendocrine tumours represent a range of tumour grade and differentiation characteristics from pre-malignant diffuse neuroendocrine cell hyperplasia, well-differentiated, low-grade carcinoid tumours with excellent outcomes, through to high-grade small-cell lung carcinoma and large-cell neuroendocrine carcinoma with poor prognoses. Rarer thymic NETs represent a similarly wide neoplastic spectrum. Cardiac carcinoid is a paraneoplastic manifestation of the carcinoid syndrome and often the cause of mortality in NETs with hepatic metastases. Cardiothoracic NET manifestations are reviewed herein from a radiologists' perspective, discussing the diverse clinical presentations, spectrum of neoplastic and paraneoplastic manifestations, imaging features and treatment options.

The UK Lung Screen (UKLS): demographic profile of first 88,897 approaches provides recommendations for population screening

The UK Lung Cancer Screening trial (UKLS) aims to evaluate low-dose computed tomography (LDCT) lung cancer population screening in the United Kingdom. In UKLS, a large population sample ages 50 to 75 years is approached with a questionnaire to determine lung cancer risk. Those with an estimated risk of at least 5% of developing lung cancer in the next 5 years (using the Liverpool Lung project risk model) are invited to participate in the trial. Here, we present demographic, risk, and response rate data from the first 88,897 individuals approached. Of note, 23,794 individuals (26.8% of all approached) responded positively to the initial questionnaire; 12% of these were high risk. Higher socioeconomic status correlated positively with response, but inversely with risk (P < 0.001). The 50- to 55-year age group was least likely to participate, and at lowest cancer risk. Only 5% of clinic attendees were ages ≤60 years (compared with 47% of all 88,897 approached); this has implications for cost effectiveness. Among positive responders, there were more ex-smokers than expected from population figures (40% vs. 33%), and fewer current smokers (14% vs. 17.5%). Of note, 32.7% of current smokers and 18.4% of ex-smokers were designated as high risk. Overall, 1,452 of 23,794 positive responders (6.1%) were deemed high risk and attended a recruitment clinic. UKLS is the first LDCT population screening trial, selecting high-risk subjects using a validated individual risk prediction model.

KEY FINDINGS

(i) better recruitment from ex- rather than current smokers, (ii) few clinic attendees ages early 50s, and (iii) representative number of socioeconomically deprived people recruited, despite lower response rates.

(18)FDG PET imaging can quantify increased cellular metabolism in pulmonary arterial hypertension: A proof-of-principle study

The past decade has seen increased application of 18-flurodeoxyglucose positron emission tomography (¹⁸FDG-PET) imaging to help diagnose and monitor disease, particularly in oncology, vasculitis and atherosclerosis. Disordered glycolytic metabolism and infiltration of plexiform lesions by inflammatory cells has been described in idiopathic pulmonary arterial hypertension (IPAH). We hypothesized that increased ¹⁸FDG uptake may be present in the lungs, large pulmonary arteries and right ventricle of patients with pulmonary hypertension, and that this uptake would be related to markers of immune activation. We imaged the thorax of 14 patients with pulmonary hypertension (idiopathic and chronic thromboembolic) and six controls by ¹⁸FDG-PET/computed tomography (CT) and measured uptake in the lung parenchyma, large pulmonary arteries and right ventricle. ¹⁸FDG uptake in the lungs and pulmonary arteries was normalized for venous blood activity to give a target-to-background ratio (TBR). Blood was contemporaneously drawn for high-sensitivity CRP - C-reactive protein (CRP) (hsCRP), N-Terminal Probrain natriuteric peptide (NT-ProBNP) and other inflammatory cytokines. IPAH patients had significantly higher lung parenchymal TBR (P=0.034) and right ventricle FDG uptake (P=0.007) than controls. Uptake in the main pulmonary arteries was similar in chronic thromboembolic pulmonary hypertension, IPAH and controls. There were no correlations between ¹⁸FDG uptake and hsCRP or inflammatory cytokine levels. NT-ProBNP correlated with RV uptake in those with pulmonary hypertension (r=0.55, P=0.04). In this pilot study, we found increased ¹⁸FDG uptake in the lung parenchyma and right ventricle of subjects with IPAH. The lung uptake might be useful as a surrogate marker of increased cellular metabolism and immune activation as underlying mechanisms in this disease. Further evaluation of the impact of targeted therapies in treatment-naïve patients and the significance of right ventricular uptake is suggested.

State-of-the-art chronic thromboembolic pulmonary hypertension diagnosis and management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a debilitating disease caused by chronic obstruction of pulmonary artery branches following episodes of pulmonary embolism and incomplete thrombus resolution. The prognosis of patients with CTEPH is poor unless an early diagnosis is made and treatment is initiated. Chest radiography and echocardiography are used in the initial assessment of suspected pulmonary hypertension. A diagnosis of CTEPH may be confirmed by the presence of a mismatched wedge-shaped perfusion deficit during ventilation/perfusion scintigraphy or characteristic findings during multi-slice computed tomography (CT) angiography, including a mosaic perfusion pattern, dilatation of proximal pulmonary arteries and right heart chambers, and the presence of vascular stenosis or obstruction. Prior to possible surgery, pulmonary angiography remains the definitive diagnostic technique, indicating the site and accessibility of the obstruction. However, many centres utilise CT and magnetic resonance imaging following recent advances in these noninvasive techniques. Haemodynamic evaluation via right heart catheterisation is also mandatory, as pulmonary vascular resistance is the most important determinant of both prognosis and the risk associated with pulmonary endarterectomy surgery. Accurate CTEPH diagnosis and characterisation of its extent and distribution are imperative to allow the prompt initiation of treatment, particularly surgical pulmonary endarterectomy in eligible patients.

Imaging in pulmonary hypertension, part 2: Large vessel diseases

Pulmonary hypertension is defined by physiological parameters but there are numerous causes that differ in their pathogenesis, management and prognosis. Causes include chronic cardiac or pulmonary diseases and diffuse small vessel disease but also a range of large vessel obstructive diseases. The physiological manifestation of all these diseases is increased pulmonary vascular resistance and pulmonary arterial hypertension, and while clinical features may provide a clue to diagnosis, imaging plays a fundamental role in establishing a precise diagnosis and therefore guiding therapy. Chronic thromboembolic pulmonary hypertension (CTEPH) is the most common large vessel cause of pulmonary hypertension. It is increasingly recognised as a major cause of morbidity and mortality which is underdiagnosed and often diagnosed late. The importance of CTEPH is that for patients in whom the distribution of disease lies predominantly in the proximal vasculature there is potential for symptomatic and physiological cure by surgical pulmonary endarterectomy. More distal disease may be suitable for medical management. Increased awareness on behalf of both clinicians and imagers is therefore paramount. However, there are other rare causes or large vessel obstruction/stenosis such as large vessel vasculitis, pulmonary artery tumour, fibrosing mediastinitis, congenital stenosis or extrinsic compression of the pulmonary arteries/veins. Atypical imaging appearance such as unilateral central pulmonary artery obstruction should lead to consideration of a diagnosis other than CTEPH.

Imaging in pulmonary hypertension, part 3: small vessel diseases

Pulmonary hypertension is a significant cause of morbidity and mortality. Unfortunately, non-specific presentation and lack of awareness of the disease frequently lead to significant delay in diagnosis, often with the onset of right heart failure, when prognosis is poor and therapy is of limited effectiveness. The classification of pulmonary hypertension is a clinical one grouping diseases into categories with similar patho-physiological mechanism and therapeutic options. Pulmonary biopsy can provide a definitive diagnosis but is hazardous in patients with pulmonary hypertension. Imaging has emerged as an invaluable tool in differentiating the aetiology, assessing disease severity and directing further management. One of the most important roles of imaging is to differentiate diseases resulting from obstruction of the large pulmonary arteries from those secondary to diffuse small vessel disease, as these have very different prognosis and are also treated differently. Small vessel diseases causing pulmonary arterial hypertension most commonly result from diffuse remodelling of the pulmonary arterioles. There are multiple causes of arteriolar remodelling which share similar histopathological, clinical and imaging features. In a subgroup of small vessel diseases causing pulmonary hypertension the predominant site of increased vascular resistance is at the level of the capillaries or venules. Correct diagnosis of pulmonary veno-occlusive disease and pulmonary capillary haemangiomatosis is essential since poor prognosis and inadvertent administration of vasodilators (conventional therapy for arteriolar predominant disease) can result in fatal pulmonary oedema. Multimodality imaging plays an important role in suggesting a diagnosis, guiding further investigation and directing treatment.

Premature ageing of the immune system underlies immunodeficiency in ataxia telangiectasia

ATM kinase modulates pathways implicated in premature ageing and ATM genotype predicts survival, yet immunodeficiency in ataxia telangiectasia is regarded as mild and unrelated to age. We address this paradox in a molecularly characterised sequential adult cohort with classical and mild variant ataxia telangiectasia. Immunodeficiency has the characteristics of premature ageing across multiple cellular and molecular immune parameters. This immune ageing occurs without previous CMV infection. Age predicts immunodeficiency in genetically homogeneous ataxia telangiectasia, and in comparison with controls, calendar age is exceeded by immunological age defined by thymic naïve CD4+ T cell levels. Applying ataxia telangiectasia as a model of immune ageing, pneumococcal vaccine responses, characteristically deficient in physiological ageing, are predicted by thymic naïve CD4+ T cell levels. These data suggest inherited defects of DNA repair may provide valuable insight into physiological ageing. Thymic naïve CD4+ T cells may provide a biomarker for vaccine responsiveness in elderly cohorts.

Pulmonary arterial size and response to sildenafil in chronic thromboembolic pulmonary hypertension

Background

Relative area change (RAC) of the proximal pulmonary artery is a measurement of pulmonary artery distensibility and has been shown to correlate with vasoreactivity studies in patients with idiopathic pulmonary arterial hypertension. We have previously noted a relationship between invasive hemodynamic vasoreactivity testing and long-term response to sildenafil in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). We therefore set out to determine whether RAC can provide useful correlatory non-invasive data.

Methods

Patients recruited to a randomized, controlled trial (RCT) of sildenafil at 40 mg 3 times daily underwent additional magnetic resonance imaging (MRI) at the baseline of the trial. Eighteen patients had an MRI that led to a diagnosis of inoperable distal CTEPH or significant residual CTEPH post-operatively. The primary end-point was improvement in 6-minute walk test (6MWT) with secondary end-points of right heart catheterization–based hemodynamics, N-terminal pro–brain natriuretic peptide (NT pro-BNP) and functional class. RAC assessed by MRI was correlated with trial end-points.

Results

Fourteen subjects with baseline MRI completed the protocol. RAC was the only baseline variable that correlated at 1 year to the primary end-point of improvement in 6MWT (r = 0.7, p = 0.006), and also to a change in NT pro-BNP (r = 0.59, p = 0.03). Using a cut-off of RAC over 20% there was an 87.5% sensitivity (95% confidence interval [CI]: 45% to 100%) and a 66.7% specificity (95% CI: 22% to 96%) for an improvement in 6MWT of >40 meters.

Conclusions

RAC correlates with functional response to sildenafil, as measured by the 6MWT, and improved heart function, as measured by NT pro-BNP. RAC shows potential in understanding and possibly predicting treatment response.

Right pulmonary artery occlusion by an acute dissecting aneurysm of the ascending aorta

We describe the case of a 76-year old female who presented with a Type A aortic dissection requiring repair with an interposition graft and aortic valve replacement. Post-operatively she had clinical features and computerised tomographic images suggestive of a pulmonary embolus and died 24 hours later. The extremely rare finding of intramural thrombus occluding the right pulmonary artery was seen at post mortem.

The surgical treatment of bronchial carcinoma

This article considers the current place of surgery in the treatment of bronchial carcinoma. Aspects of the diagnosis of this condition will be covered, but the main focus falls on the surgical procedures, their complications and the outlook for these patients according to tumour stage.

Modeling leg sections by bioelectrical impedance analysis, dual-energy X-ray absorptiometry, and anthropometry: assessing segmental muscle volume using magnetic resonance imaging as a reference

This study aimed to assess the value of different DXA and BIA models for predicting muscle volume in mid-thigh segments obtained by MRI. Three DXA models were used: in model A, muscle was taken to be equivalent to fat-free soft tissue; in model B the thigh segment was divided into its constituent tissues using fixed assumptions about tissue composition; in model C the assumptions were similar to model B, but with variable distribution of fat and fat-free soft tissue, depending on body mass index. The two BIA models (both parallel tissue resistance models) involved impedance measurements at 50 kHz, and assumptions about either the specific resistivities of all the constituent tissues (model A), or resistivities of only adipose tissue and muscle (model B). Anthropometric estimates (thigh circumference and skinfold thickness) assumed that both limb and muscle circumference were circular. Compared to MRI estimates of muscle mass, those obtained by DXA model A (fat-free soft tissue) were not as good as those obtained using models B and C, although the standard deviations of the differences were similar with all three models. The BIA models were superior to the anthropometric estimates of muscle volume (relative to MRI) with respect to bias, but the standard deviations of the differences were large for both. The intraobserver repeatabilities for muscle volume were < 0.5% for MRI, < 1% for DXA, 1.8% for BIA, and 1.7% for anthropometry (interobserver value for BIA was 3.8% and for anthropometry 3.5%). The study suggests that DXA modeling provides a promising approach for assessing muscle mass in thigh segments, and suggests the potential value of parallel BIA models for groups of individuals but not for individual subjects, possibly because muscle resistivity is influenced not only by its composition but also by the direction of current flow in muscle.

Assessment of limb muscle and adipose tissue by dual-energy X-ray absorptiometry using magnetic resonance imaging for comparison

OBJECTIVE

To use magnetic resonance imaging (MRI) to validate estimates of muscle and adipose tissue (AT) in lower limb sections obtained by dual-energy X-ray absorptiometry (DXA) modelling.

DESIGN

MRI measurements were used as reference for validating limb muscle and AT estimates obtained by DXA models that assume fat-free soft tissue (FFST) comprised mainly muscle: model A accounted for bone hydration only; model B also applied constants for FFST in bone and skin and fat in muscle and AT; model C was as model B but allowing for variable fat in muscle and AT.

SUBJECTS

Healthy men (n = 8) and women (n = 8), ages 41-62y; mean (s.d.) body mass indices (BMIs) of 28.6 (5.4) kg/m2 and 25.1 (5.4) kg/m2, respectively.

MEASUREMENTS

MRI scans of the legs and whole body DXA scans were analysed for muscle and AT content of thigh (20 cm) and lower leg (10 cm) sections; 24h creatinine excretion was measured.

RESULTS

Model A overestimated thigh muscle volume (MRI mean, 2.3 l) substantially (bias 0.36 l), whereas model B underestimated it by only 2% (bias 0.045 l). Lower leg muscle (MRI mean, 0.6 l) was better predicted using model A (bias 0.04 l, 7% overestimate) than model B (bias 0.1 l, 17% underestimate). The 95% limits of agreement were high for these models (thigh, +/-20%; lower leg, +/-47%). Model C predictions were more discrepant than those of model B. There was generally less agreement between MRI and all DXA models for AT. Measurement variability was generally less for DXA measurements of FFST (coefficient of variation 0.7-1.8%) and fat (0.8-3.3%) than model B estimates of muscle (0.5-2.6%) and AT (3.3-6.8%), respectively. Despite strong relationships between them, muscle mass was overestimated by creatinine excretion with highly variable predictability.

CONCLUSION

This study has shown the value of DXA models for assessment of muscle and AT in leg sections, but suggests the need to re-evaluate some of the assumptions upon which they are based.