Chronic thromboembolic pulmonary hypertension: detection, medical and surgical treatment approach, and current outcomes

CTEPH: A Kaiser Permanente Northern California Experience

INTRODUCTION

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and life-threatening form of pulmonary hypertension and the only potentially curable form of the World Health Organization Pulmonary Hypertension classes. Thus, the prompt and accurate diagnosis of this condition is imperative. Despite widespread chronic symptoms following acute pulmonary embolism (PE), the condition is rarely considered, and an externally validated inexpensive diagnostic algorithm is lacking.

METHODS

A long-term, retrospective cohort study was conducted to assess the incidence of CTEPH following acute PE in a real-world study population. Additional data were collected regarding the practice patterns of diagnostic testing and imaging, particularly in patients with persistent or recurrent symptoms. Amongst diagnosed CTEPH patients, previously established risk factors were evaluated for degree of risk and commonly used diagnostic tests (electrocardiogram [ECG] right ventricular hypertrophy [RVH] pattern, B-type natriuretic peptide [BNP] elevations) employed during this period were evaluated and assessed for feasibility as screening tests. The study population was obtained from the MAPLE study cohort, comprised of patients presenting with acute PE in 21 community medical centers across the Kaiser Permanente Northern California system from January 2013 to April 2015. Diagnosis of CTEPH was confirmed via pulmonary vascular imaging (ventilation/perfusion [V/Q] scanning, computed tomography angiography, pulmonary angiography) and diagnostic right heart catheterization (RHC). Probable diagnoses were defined as a combination of suggestive echocardiographic and RHC findings. Additional inclusion criteria included age (≥18 years) with at least 2 years follow up and no previous diagnosis of CTEPH or PE during the prior 30 days.

RESULTS

There were 1973 patients who met inclusion criteria (mean age 62.4 years). Despite 75 % of patients developing symptoms consistent with CTEPH >3 months following acute PE, only 5.6 % of these symptomatic patients underwent V/Q scanning. There was overall a very low cumulative incidence of CTEPH (2.3 %), which was significantly higher amongst patients with symptoms compared to those without symptoms. When controlled for confounding in the multivariate analysis, only recurrent PE (HR 19.3, P < 0.001) and pulmonary artery systolic pressure >50 mmHg (HR 10.4, P < 0.001) were statistically significant predictors of CTEPH. Of the non-invasive diagnostic tests, ECG criteria for RVH were found to be poorly sensitive (2.6 %), but very specific (98.8 %) for CTEPH. Elevated levels of BNP alone were more sensitive than RVH ECG criteria (76.3 %) but poorly specific (44.4 %).

CONCLUSIONS

The diagnosis of CTEPH is uncommonly made following acute PE. Despite the frequency of persistent symptoms consistent with CTEPH following acute PE, the appropriate diagnostic work-up is rarely undertaken as evidenced in this cohort. This suggests that CTEPH is underappreciated and rarely considered, likely underestimating the true incidence in this cohort. Future studies are needed to elucidate the true prevalence of CTEPH and further investigate both the optimal diagnostic tools and timing of appropriate screening. These discoveries may help guide future development of diagnostic algorithms that can effectively rule out and accurately identify this potentially curable disease in a timely manner.

The outcome of reoperative pulmonary endarterectomy surgery

OBJECTIVES

Pulmonary endarterectomy (PEA) is the treatment of choice for patients with chronic thromboembolic pulmonary hypertension (PH). Despite excellent outcomes following PEA, a small proportion of patients have residual proximal disease or present with recurrent chronic thromboembolic PH and may benefit from further surgery. The aim of this study was to analyse outcomes following reoperative PEA at a high-volume national tertiary referral centre for the management of chronic thromboembolic PH.

METHODS

This retrospective analysis was performed using our prospectively maintained PH database to identify all patients who underwent reoperative PEA surgery between the commencement of the programme in 1997 and January 2017, and the patients' data were collected for analysis.

RESULTS

Twelve patients underwent reoperative PEA during the period of study. The mean interval between primary procedure and reoperative procedure was 6.3 years. Significant improvements were observed in pulmonary haemodynamics following reoperative PEA. Mean pulmonary arterial pressure decreased from 46.8 to 29.8 mmHg (P < 0.0001) and pulmonary vascular resistance decreased from 662 to 362 dyne·s·cm-5 (P = 0.0007). A significant functional improvement in the 6-min walking test distance was also observed, increasing from 327 to 460 m at 6 months postoperatively (P = 0.0018). Median length of hospital stay was 12 days. In-hospital mortality was 8.3% with 1-year survival of 83.3%.

CONCLUSIONS

Reoperative PEA is technically possible and relatively safe, achieving good functional and physiological outcomes. Patients must be carefully selected by a multidisciplinary team, and surgery should be performed in experienced centres.

Evaluation of a newly developed 2D parametric parenchymal blood flow technique with an automated vessel suppression algorithm in patients with chronic thromboembolic pulmonary hypertension undergoing balloon pulmonary angioplasty

AIM

To evaluate the feasibility of two-dimensional parametric parenchymal blood flow (2D-PPBF) to quantify perfusion changes in the lung parenchyma following balloon pulmonary angioplasty (BPA) for treatment of chronic thromboembolic pulmonary hypertension.

MATERIALS AND METHODS

Overall, 35 consecutive interventions in 18 patients with 98 treated pulmonary arteries were included. To quantify changes in pulmonary blood flow using 2D-PPBF, the acquired digital subtraction angiography (DSA) series were post-processed using dedicated software. A reference region of interest (ROI; arterial inflow) in the treated pulmonary artery and a distal target ROI, including the whole lung parenchyma distal to the targeted stenosis, were placed in corresponding areas on DSA pre- and post-BPA. Half-peak density (HPD), wash-in rate (WIR), arrival to peak (AP), area under the curve (AUC), and mean transit time (MTT) were assessed. The ratios of the reference ROI to the target ROI (HPD_parenchyma/HPD_inflow, WIR_parenchyma/WIR_inflow; AP_parenchyma/AP_inflow, AUC_parenchyma/AUC_inflow, MTT_parenchyma/MTT_inflow) were calculated. The relative differences of the 2D-PPBF parameters were correlated to changes in the pulmonary flow grade score.

RESULTS

The pulmonary flow grade score improved significantly after BPA (1 versus 3; p<0.0001). Likewise, the mean HPD_parenchyma/HPD_inflow (-10.2%; p<0.0001), AP_parenchyma/AP_inflow (-24.4%; p=0.0007), and MTT_parenchyma/MTT_inflow (-3.5%; p=0.0449) decreased significantly, whereas WIR_parenchyma/WIR_inflow (+82.4%) and AUC_parenchyma/AUC_inflow (+58.6%) showed a significant increase (p<0.0001). Furthermore, a significant correlation between changes of the pulmonary flow grade score and changes of HPD_parenchyma/HPD_inflow (ρ=-0.21, p=0.04), WIR_parenchyma/WIR_inflow (ρ=0.43, p<0.0001), AP_parenchyma/AP_inflow (ρ=-0.22, p=0.03), AUC_parenchyma/AUC_inflow (ρ=0.48, p<0.0001), and MTT_parenchyma/MTT_inflow (ρ=-0.39, p<0.0001) could be observed.

CONCLUSION

The 2D-PPBF technique is feasible for the quantification of perfusion changes following BPA and has the potential to improve monitoring of BPA.

Predictors of Chronic Thromboembolic Pulmonary Hypertension

PURPOSE

to elucidate predictors of development of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary artery thromboembolism (PTE).

MATERIAL AND METHODS

We included in this study 210 patients hospitalized with diagnosis of submassive and massive PTE from 2013 to 2017. In 1 to 3 years after initial hospitalization these patients were invited for control examination. According to results of this examination patients were divided into two groups: with (group 1, n=45) and without (group 2, n=165) signs of CTEPH. Severity of pulmonary artery vascular bed involvement was assessed by multislice computed tomography (MSCT) angiography and lung scintigraphy. For detection of thrombosis in the inferior vena cava system we used ultrasound angioscanning.   Examination also included echocardiography.

RESULTS

In the process of mathematical analysis, the following risk factors for the development of CTEPH embolism were determined: duration of thrombotic history (group 1 - 13.70±2.05 days, group 2- 16.16±1.13 days, p=0.015), localization of venous thrombosis in the lower extremities (the most favorable - shin veins, popliteal, and common femoral veins, unfavorable - superficial femoral vein). The choice of the drug for thrombolytic and anticoagulant therapy: streptokinase and urokinase were significantly more effective than alteplase, rivaroxaban was superior to the combination of unfractionated or low molecular weight heparins with warfarin. Also, risk factors for the development of CTEPH were the initial degree of pulmonary hypertension and tricuspid insufficiency, as well as the positive dynamics of these indicators at the background of thrombolytic or anticoagulant therapy. Of concomitant diseases, significant risk factors for development of CTEPH were grade 3 hypertensive disease, diabetes mellitus, post-infarction cardiosclerosis. On the other hand, age, gender, degree of severity at the time of admission, presence of infarction pneumonia, surgical prevention of recurrent pulmonary embolism, number of pregnancies and deliveries, history of trauma and malignancies, cardiac arrhythmias produced no significant impact on the development of CTEPH.

Case series of seven women with uterine fibroids associated with venous thromboembolism and chronic thromboembolic disease

Uterine fibroids have been described as an associate to acute venous thromboembolism (VTE), with case reports showing an association between large uterine fibroids, acute deep venous thrombosis (DVT), and acute pulmonary embolism (PE). However, there is little known about the association or causation between uterine fibroids, chronic thromboembolic disease (CTED), and chronic thromboembolic pulmonary hypertension (CTEPH). We report on six women with uterine fibroids and CTEPH, as well as one woman with CTED, all of whom presented with exertional dyspnea, lower extremity swelling, and in the cases of CTEPH, clinical, echocardiographic, and hemodynamic evidence of pulmonary hypertension and right heart failure. Compression of the pelvic veins by fibroids was directly observed with invasive venography or contrast-enhanced computed tomography in five cases. All seven women underwent pulmonary thromboendarterectomy (PTE) followed by marked improvement in functional, clinical, and hemodynamic status.

Chronic thromboembolic pulmonary hypertension: Evaluation of 2D-perfusion angiography in patients who undergo balloon pulmonary angioplasty

OBJECTIVE

To evaluate the feasibility of 2D-perfusion angiography (2D-PA) in order to quantify perfusion changes of the lung parenchyma pre- and post-balloon pulmonary angioplasty (BPA).

METHODS

Thirty consecutive interventions in 16 patients with 99 treated pulmonary artery segments were included. To quantify changes in pulmonary blood flow using 2D-PA, the acquired digital subtraction angiographies (DSA) pre- and post-BPA were post-processed. A reference ROI in the treated pulmonary artery and a distal target ROI in the lung parenchyma were placed in corresponding areas on DSA pre- and post-BPA. Time to peak (TTP), peak density (PD) and area under the curve (AUC) were assessed. The ratios reference ROI to target ROI (TTP_parenchyma/TTP_inflow; PD_parenchyma/PD_inflow; AUC_parenchyma/AUC_inflow) were calculated. Relative differences of the 2D-PA parameters were correlated to changes in the pulmonary-flow-grade-score.

RESULTS

The pulmonary-flow-grade-score improved after BPA (p<0.0001). Likewise, the ratio TTP_parenchyma/TTP_inflow shortened by 10% (p=0.0002), the PD_parenchyma/PD_inflow increased by 46% (p<0.0001) and the AUC_parenchyma/AUC_inflow increased by 36% (p<0.0001). A significant correlation between changes in the pulmonary-flow-grade-score and changes in PD_parenchyma/PD_inflow (ρ=0.48, p<0.0001) and AUC_parenchyma/AUC_inflow (ρ=0.31, p=0.0018) was observed.

CONCLUSION

Quantification of pulmonary perfusion pre- and post-BPA using 2D-PA is feasible and has the potential to improve monitoring of BPA.

KEY POINTS

• Quantification of BPA results by use of 2D-PA is feasible. • 2D-PA allows objective assessment of changes in lung parenchymal perfusion. • 2D-PA has the potential to optimize BPA.

Pulmonary endarterectomy in the management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a type of pulmonary hypertension, resulting from fibrotic transformation of pulmonary artery clots causing chronic obstruction in macroscopic pulmonary arteries and associated vascular remodelling in the microvasculature.

Pulmonary endarterectomy (PEA) offers the best chance of symptomatic and prognostic improvement in eligible patients; in expert centres, it has excellent results. Current in-hospital mortality rates are <5% and survival is >90% at 1 year and >70% at 10 years. However, PEA, is a complex procedure and relies on a multidisciplinary CTEPH team led by an experienced surgeon to decide on an individual's operability, which is determined primarily by lesion location and the haemodynamic parameters. Therefore, treatment of patients with CTEPH depends largely on subjective judgements of eligibility for surgery by the CTEPH team.

Other controversies discussed in this article include eligibility for PEA versus balloon pulmonary angioplasty, the new treatment algorithm in the European Society of Cardiology/European Respiratory Society guidelines and the definition of an “expert centre” for the management of this condition.

An Update on the Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening form of pulmonary artery hypertension that is defined as a mean arterial pulmonary pressure greater than 25mmHg that persists for more than 6 months following anticoagulation therapy in the setting of pulmonary emboli. CTEPH is categorized by the World Health Organization as group IV pulmonary hypertension and is thought to be due to unresolved thromboemboli in the pulmonary artery circulation. Among the 5 classes of pulmonary hypertension, CTEPH is unique in that it is potentially curable with the use of pulmonary thromboendarterectomy surgery. Despite an increasing array of medical and surgical treatment options for patients with CTEPH over the past 2 decades, patients commonly present with advanced disease and carry a poor prognosis, thus, the need for early diagnosis and appropriate referral to an expert center. This review article first highlights the epidemiology, pathophysiology, and clinical presentation of CTEPH. The article then provides diagnostic and therapeutic algorithms for the management of the patient with suspected CTEPH.

Global Anticoagulant Registry in the Field - Venous Thromboembolism (GARFIELD-VTE). Rationale and design

Venous thromboembolism (VTE) is a common disorder associated with significant rates of morbidity and mortality. VTE management aims to reduce mortality, the risks of recurrence, and long-term complications. VTE treatment is evolving with the introduction of non-vitamin K antagonist anticoagulants (NOACs). The Global Anticoagulant Registry in the FIELD - Venous Thromboembolism (GARFIELD-VTE) is a prospective, multicentre, observational study that will enrol 10,000 patients treated for acute VTE from ~500 sites in 28 countries. Identified sites reflect the diversity of care settings, including hospital and outpatient settings. Patients will be managed according to local practices and followed for at least three years. The primary objective is to determine the extent to which VTE treatment varies in the real-world setting and to assess the impact of such variability on clinical and economic outcomes. Evolving patterns of care will be captured using two sequential cohorts. The GARFIELD-VTE registry will provide insights into the evolving global treatment patterns for VTE, both deep-vein thrombosis and pulmonary embolism. By enrolling patients from diverse care settings, the registry will provide information on adherence to national and international guidelines, identify good practice as well as treatment deficiencies, and relate patient outcomes to clinical management. The incidence of death, recurrent VTE, bleeding, post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension will be documented. By capturing information during and after anticoagulation treatment, the registry will not only define aspects of the natural history of VTE, but also its economic and societal impact at a regional and global level.