Prognostic factors in medically treated patients with chronic pulmonary embolism

Long-term advanced therapy with bosentan improves symptoms and prevents deterioration of inoperable chronic thromboembolic pulmonary hypertension

AIMS

Chronic thromboembolic pulmonary hypertension (CTEPH) is a devastating disease, and treating patients with CTEPH who are not eligible for pulmonary endarterectomy is particularly challenging. Short-term bosentan or phosphodiesterase type-5-inhibitor treatment can greatly improve symptoms and hemodynamics in these patients; however, the long-term benefits of advanced pulmonary vasodilators are not known. We retrospectively investigated the long-term effects of advanced pharmacological therapy in Japanese patients with inoperable CTEPH.

MAIN METHODS

Seven consecutive patients with inoperable CTEPH (five women; mean age, 62.6±6.9 years) treated with bosentan were included. World Health Organization functional class (WHO-FC), hemodynamics, exercise capacity, and plasma B-type natriuretic peptide (BNP) concentration were evaluated at baseline and for more than 2 years. Time to clinical worsening was also examined during long-term follow-up.

KEY FINDINGS

WHO-FC improved significantly, from 3.1±0.4 to 2.1±0.4 (p=0.005). Significant improvement was also seen in pulmonary vascular resistance, which decreased from 786.9±300.0 to 352.2±210.7 dynes s cm(-5) (p<0.05). Plasma BNP concentration decreased significantly from 1160.0±971.4 to 305.1±285.9 pg/mL (p<0.05). No patient required hospitalization during the follow-up period (mean, 896±564 days).

SIGNIFICANCE

Long-term advanced therapy with bosentan significantly improves symptoms, pulmonary vascular resistance, plasma BNP concentration, and time to clinical worsening in Japanese patients with inoperable CTEPH. We consider bosentan to be an essential treatment for these patients.

Long-term patient survival with idiopathic/heritable pulmonary arterial hypertension treated at a single center in Japan

AIMS

Idiopathic/heritable pulmonary arterial hypertension (I/HPAH) carries a poor prognosis despite the therapeutic options available. Patient survival from Western countries has been reported, but data from Asia are scarce.

MAIN METHODS

We retrospectively reviewed 56 patients with I/HPAH treated at a single referral center in Japan. Survival analyses were conducted using the Kaplan-Meier method with the log-rank test. Variables associated with survival were determined using a Cox proportional hazard model.

KEY FINDINGS

There were 41 women (73%) and the mean age at the diagnosis was 32±17 years. Mean survival time from the diagnosis was 14.9±0.8 years (95% CI, 13.4-16.4 years), with 1-, 2-, 3-, 5- and 10-year survival rates of 98, 96, 96, 96 and 78%, respectively. In patients who underwent follow-up right-heart catheterization >3 months after initial catheterization, mean pulmonary arterial pressure (mPAP) was decreased significantly from 63±15 to 35±10 mm Hg with an improved cardiac index. Patients with high levels of brain natriuretic peptide (BNP) or low oxygen saturation at baseline showed worse survival. At follow-up, 98% of patients were on PAH-targeted drugs. WHO functional classes I and II, mPAP <42.5 mm Hg, cardiac index >2.5 L/min/m(2), BNP <52 pg/mL, and 6-min walk distance >347 m at follow-up were predictors of good prognosis in the univariate analysis.

SIGNIFICANCE

The study revealed a long-term survival of Japanese patients with I/HPAH. Hemodynamic parameters improved significantly after treatment, which might be related to high prescription rates of PAH-targeted drugs. Multicenter studies are needed to reveal the prognostic factors for I/HPAH.

Evaluation of right ventricular function in patients with a previous episode of pulmonary embolism using tissue Doppler imaging

New echocardiographic techniques including tricuspid annular plane systolic excursion (TAPSE) and pulsed tissue Doppler imaging (TDI) of the right ventricular wall have been assessed to better define right ventricular dysfunction (RVD) during the acute phase of pulmonary embolism (PE) in patients without significant tricuspidal insufficiency. Their application in patients with a previous history of PE may provide a better estimation of the incidence and clinical significance of long-term functional impairment of the right ventricle. In a case-control study, we compared the prevalence of RVD in a cohort of consecutive patients with previous PE and in age and sex-matched controls without PE. Exclusion criteria were moderate-severe left heart failure, moderate-severe mitral valve regurgitation, severe tricuspid insufficiency, or other causes of chronic pulmonary hypertension. Systolic and diastolic right ventricular functions were evaluated by measuring TAPSE and TDI of the right ventricular wall. Twenty-five patients with a previous first episode of PE and 25 controls were enrolled. Mean value of TAPSE was similar between patients with previous PE and controls (2.58 ± 0.33 and 2.53 ± 0.35 cm, P = ns). In patients with PE, the mean value of E″/A″ was significantly lower than in controls (0.89 ± 0.24 vs. 1.30 ± 0.39, P < 0.001), with 14 out of 25 cases having diastolic dysfunction as compared to only 3 out of 25 controls (P < 0.002). A high proportion of patients with previous PE have echocardiographic signs of RV diastolic dysfunction 6 months after the acute phase, even in the absence of symptoms, and in the presence of normal pulmonary pressures.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a disease with high mortality and few treatment options. This article reviews the epidemiology of CTEPH and identifies risk factors for its development. The pathobiology and the progression from thromboembolic events to chronically increased right-sided pressures are discussed. The diagnosis and assessment of CTEPH requires several modalities and the role of these is detailed. The pre-operative evaluation assesses peri-operative risk and determines the likelihood of benefit from PTE. Pulmonary thromboendarterectomy (PTE) remains the treatment of choice in appropriate patients. Nonsurgical therapies for CTEPH may provide benefit in patients who cannot be offered surgery.

Balloon pulmonary angioplasty in patients with inoperable chronic thromboembolic pulmonary hypertension

OBJECTIVE

To examine the effect of balloon pulmonary angioplasty (BPA) on chronic thromboembolic pulmonary hypertension (CTEPH) in patients with inoperable disease or persistent pulmonary hypertension after pulmonary endarterectomy.

DESIGN

Observational cohort study.

SETTING

Referred patients with inoperable or persistent CTEPH.

PATIENTS

Twenty consecutive CTEPH patients (10 females), aged 60±10 years.

INTERVENTIONS BPA MAIN OUTCOME MEASURES

Right heart catheterisation, functional capacity (cardiopulmonary exercise testing (CPET) and NYHA class) and blood sampled biomarkers N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T examined at the time of diagnosis and repeated in all patients 3 months after the last BPA.

RESULTS

Seventy-three catheterisations were performed with 18.6±6.1 BPAs per patient on segmental and subsegmental arteries. Two deaths occurred following the first BPA, with an overall 10% periprocedural death rate. Reperfusion oedema complicated seven procedures. Comparisons before and after BPA showed significant haemodynamic improvements, including decreased mean pulmonary artery pressure (mPAP) (45±11 mm Hg vs 33±10 mm Hg; p<0.001) and increased cardiac output (4.9±1.6 L/min vs 5.4±1.9 L/min; p=0.011). Reduced right ventricular strain was indicated by significantly lower plasma levels of NT-proBNP and troponin T. Significant improvement in functional capacity was evident as assessed by NYHA class (3.0±0.5 vs 2.0±0.5; p<0.001) and CPET (13.6±5.6 mL/kg/min vs 17.0±6.5 mL/kg/min; p<0.001). Seventeen patients (85%) were alive after 51±30 months of follow-up.

CONCLUSIONS

BPA may offer an alternative form of treatment in selected CTEPH patients. While prognostic markers such as haemodynamics, functional capacity and biomarkers improve, significant periprocedural complications must be recognised. Randomised trials are warranted.

Improved survival in patients with inoperable chronic thromboembolic pulmonary hypertension

Patients with inoperable chronic thromboembolic pulmonary hypertension (Inop-CTEPH) treated with conventional therapy have a poor survival. We compare the 3-year survival between those treated with conventional therapy and those treated with conventional therapy and a combination of novel drugs. We also evaluate the clinical course. A total of 34 Inop-CTEPH consecutive patients were evaluated from 1991 to 2009 including right heart catheterization (RHC) and perfusion lung scan (PLS): 7 underwent surgical treatment while 27 were confirmed inoperable. Of these 27 patients, 12 evaluated from 1991 to 2003 (Group 1) were treated with conventional therapy and 15 evaluated from 2004 to 2009 (Group 2) were treated with conventional and novel therapies. At baseline, no group difference emerged at RHC. Based on clinical course, novel drugs and oxygen supplementation were given to patients of Group 2. Seven of these who had worse clinical course repeated RHC and four of them also PLS during therapy. Those without repeat RHC had baseline pulmonary artery mean pressure and brain natriuretic peptide (NT-proBNP) lower and mixed venous saturation (SvO2) and exercise test higher (p = 0.022, 0.015, 0.044 and 0.003, respectively). During therapy, those with repeat RHC had total pulmonary vascular resistance reduced (p = 0.012), base excess increased (p = 0.002) and significant redistribution of pulmonary blood flow at PLS. At the 3-year follow-up, survival was 86% in Group 2 and 31% in Group 1 (p = 0.031). In Inop-CTEPH patients, the clinical course may help to select drugs and the level of oxygen supply that can improve hemodynamics, gas exchange and long-term survival.

Chronic pulmonary emboli and radiologic mimics on CT pulmonary angiography: a diagnostic challenge

Chronic pulmonary thromboembolism (CPE) is a challenging diagnosis for clinicians. It is an often-forgotten diagnosis and can be difficult to detect and easily misdiagnosed. The radiologic features on CT pulmonary angiography are subtle and can be further compounded by pathologic mimics and unusual findings observed with disease progression. Diagnosis is important because CPE can lead to progressive pulmonary hypertension, morbidity, and mortality. Moreover, chronic thromboembolic pulmonary hypertension is the only category of pulmonary hypertension with an effective curative treatment in the form of pulmonary endarterectomy. Therefore, CPE must be considered and recognized early. The features of chronic pulmonary emboli on CT scans can be categorized into vascular or parenchymal findings. Endoluminal signs include totally or partially occlusive thrombi and webs and bands. Parenchymal features such as mosaic attenuation and pulmonary infarction are also noted, in addition to features of pulmonary artery hypertension. Additional findings have been noted, including cavitation of infarcts, microbial colonization of cavities, and bronchopleural fistulae. As CPE can be diagnosed at different stages of its disease pathway, such findings may not necessarily arouse suspicion toward a causative diagnosis of chronic embolism. To aid diagnosis for clinicians, this article describes the characteristic vascular and parenchymal CT scan features of chronic emboli, as well as important ancillary findings. We also provide an illustrative case series focusing on CT pulmonary angiography specifically as an imaging modality to highlight the progressive nature of CPE and its sequelae, as well as important radiologic mimics to consider in the differential diagnosis.

An Australian tertiary referral center experience of the management of chronic thromboembolic pulmonary hypertension

The objective of this study was to report the outcome of pulmonary endarterectomy (PEA) surgery performed for chronic thromboembolic pulmonary hypertension (CTEPH) at a single tertiary center. The prospective study consisted of 35 patients with surgically amenable CTEPH undergoing PEA between September 2004 and September 2010. The main outcome measures were Functional (New York Heart Association [NYHA] class, 6-Minute Walk Distance), hemodynamic (echocardiography, right heart catheterization, and cardiac MRI), and outcome data (morbidity and mortality). Following PEA, there were significant improvements in NYHA class (pre 2.9±0.7 vs. post 1.3±0.5, P < 0.0001), right ventricular systolic pressure (pre 77.4±24.8 mmHg vs. post 45.1±24.9 mmHg, P = 0.0005), 6-Minute Walk Distance (pre 419.6±109.4 m vs. post 521.6±83.5 m, P = 0.0017), mean pulmonary artery pressure (pre 41.8±15.3 mmHg vs. post 24.7±8.8 mmHg, P = 0.0006), and cardiac MRI indices (end diastolic volume pre 213.8±49.2 mL vs. post 148.1±34.5 mL, P < 0.0001; ejection fraction pre 40.7±9.8 mL vs. post 48.1±8.9 mL, P = 0.0069). The mean cardiopulmonary bypass time was 258.77±26.16 min, with a mean circulatory arrest time of 43.83±28.78 min, a mean ventilation time of 4.7±7.93 days (range 0.2-32.7), and a mean intensive care unit stay of 7.22±8.71 days (range 1.1-33.8). Complications included reperfusion lung injury (20%), persistent pulmonary hypertension (17.1%), slow respiratory wean (25.7%), pericardial effusion (11.4%), and cardiac tamponade (5.7%). 1-year mortality post-procedure was 11.4%. Pulmonary endarterectomy can be performed safely with relatively low mortality.

Refined balloon pulmonary angioplasty for inoperable patients with chronic thromboembolic pulmonary hypertension

BACKGROUND

Although balloon pulmonary angioplasty (BPA) for inoperable patients with chronic thromboembolic pulmonary hypertension was first reported over a decade ago, its clinical application has been restricted because of limited efficacy and complications. We have refined the procedure of BPA to maximize its clinical efficacy.

METHODS AND RESULTS

Sixty-eight consecutive patients with inoperable chronic thromboembolic pulmonary hypertension underwent BPA. We evaluated pulmonary artery diameters and determined the appropriate balloon size by using intravascular ultrasound. We performed BPA in a staged fashion over multiple, separate procedures to maximize efficacy and reduce the risk of reperfusion pulmonary injury. A total of 4 (2-8) sessions were performed in each patient, and the number of vessels dilated per session was 3 (1-14). The World Health Organization functional class improved from 3 to 2 (P<0.01), and mean pulmonary arterial pressure was decreased from 45.4 ± 9.6 to 24.0 ± 6.4 mm Hg (P<0.01). One patient died because of right heart failure 28 days after BPA. During follow-up for 2.2 ± 1.4 years after the final BPA, another patient died of pneumonia, and the remaining 66 patients are alive. In 57 patients who underwent right heart catheterization at follow-up, improvement of mean pulmonary arterial pressure was maintained (24.0 ± 5.8 mm Hg at 1.0 ± 0.9 years). Forty-one patients (60%) developed reperfusion pulmonary injury after BPA, but mechanical ventilation was required in only 4 patients.

CONCLUSIONS

Our refined BPA procedure improves clinical status and hemodynamics of inoperable patients with chronic thromboembolic pulmonary hypertension, with a low mortality. A refined BPA procedure could be considered as a therapeutic approach for patients with inoperable chronic thromboembolic pulmonary hypertension.

Classification of pulmonary hypertension

Pulmonary hypertension (PH) can develop in association with many different diseases and risk factors, and its presence is nearly always associated with reduced survival. The prognosis and management of PH is largely dependent upon its underlying etiology and severity of disease. The combination of clinical and hemodynamic classifications of PH provides a framework for the diagnostic evaluation of PH to establish a final clinical diagnosis that guides therapy. As our understanding of the different pathologic mechanisms that underlie the syndrome of PH evolves, so too will the classification and treatment of PH.

Evaluation of patients with chronic thromboembolic pulmonary hypertension for pulmonary endarterectomy

Pulmonary hypertension as a result of chronic thromboembolic disease (CTEPH) is potentially curable with pulmonary endarterectomy surgery. Consequently, correctly diagnosing patients with this type of pulmonary hypertension and evaluating these patients with the goal of establishing their candidacy for surgical intervention is of utmost importance. And as advancements in surgical techniques have allowed successful resection of segmental-level chronic thromboembolic disease, the number of CTEPH patients that are deemed suitable surgical candidates has expanded, making it even more important that the evaluation be conducted with greater precision. This article will review a diagnostic approach to patients with suspected chronic thromboembolic disease with an emphasis on the criteria considered in selecting patients for pulmonary endarterectomy surgery.

Diagnostic evaluation and management of chronic thromboembolic pulmonary hypertension: a clinical practice guideline

BACKGROUND

Pulmonary embolism is a common condition. Some patients subsequently develop chronic thromboembolic pulmonary hypertension (CTEPH). Many care gaps exist in the diagnosis and management of CTEPH patients including lack of awareness, incomplete diagnostic assessment, and inconsistent use of surgical and medical therapies.

METHODS

A representative interdisciplinary panel of medical experts undertook a formal clinical practice guideline development process. A total of 20 key clinical issues were defined according to the patient population, intervention, comparator, outcome (PICO) approach. The panel performed an evidence-based, systematic, literature review, assessed and graded the relevant evidence, and made 26 recommendations.

RESULTS

Asymptomatic patients postpulmonary embolism should not be screened for CTEPH. In patients with pulmonary hypertension, the possibility of CTEPH should be routinely evaluated with initial ventilation/perfusion lung scanning, not computed tomography angiography. Pulmonary endarterectomy surgery is the treatment of choice in patients with surgically accessible CTEPH, and may also be effective in CTEPH patients with disease in more 'distal' pulmonary arteries. The anatomical extent of CTEPH for surgical pulmonary endarterectomy is best assessed by contrast pulmonary angiography, although positive computed tomography angiography may be acceptable. Novel medications indicated for the treatment of pulmonary hypertension may be effective for selected CTEPH patients.

CONCLUSIONS

The present guideline requires formal dissemination to relevant target user groups, the development of tools for implementation into routine clinical practice and formal evaluation of the impact of the guideline on the quality of care of CTEPH patients. Moreover, the guideline will be updated periodically to reflect new evidence or clinical approaches.

Clinical worsening during long-term follow-up in inoperable chronic thromboembolic pulmonary hypertension

BACKGROUND

Pulmonary endarterectomy is the treatment of choice in chronic thromboembolic pulmonary hypertension (CTEPH). Modern pulmonary vasoactive medication (like endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and prostacyclins) is used in patients with an inoperable disease and improved prognosis. We evaluate mortality and time to clinical worsening (TtCW) in inoperable CTEPH patients during long-term follow-up.

METHODS

All 32 patients with inoperable CTEPH were enrolled between June 2002 and January 2009. TtCW was defined as the combination of death, need for intravenous pulmonary arterial hypertension medication, or 15% decrease in 6-minute walk distance (6-MWD) without improvement in functional class. The Cox proportional hazard regression was used to identify predictors.

RESULTS

During a mean follow-up of 3.4 years (range = 0.2-10.2 years), 11 patients died (34%). The 1- and 3-year survival rates were 87 and 77%, respectively. Baseline functional class, 6-MWD, mean pulmonary artery pressure, and pulmonary vascular resistance were predictors for survival. Clinical worsening occurred in 16 patients (50%). The 1- and 3-year rates of freedom from clinical worsening were 74 and 60%, respectively. The only predictor for clinical worsening was the baseline 6-MWD.

CONCLUSION

Despite the improvement in medical treatment of inoperable CTEPH, the mortality rate is still high, and clinical worsening occurred in a substantial number of patients during a follow-up of more than 3 years.

Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

Background—

Chronic thromboembolic pulmonary hypertension (CTEPH) is often a sequel of venous thromboembolism with fatal natural history; however, many cases can be cured by pulmonary endarterectomy. The clinical characteristics and current management of patients enrolled in an international CTEPH registry was investigated.

Methods and Results—

The international registry included 679 newly diagnosed (≤6 months) consecutive patients with CTEPH, from February 2007 until January 2009. Diagnosis was confirmed by right heart catheterization, ventilation-perfusion lung scintigraphy, computerized tomography, and/or pulmonary angiography. At diagnosis, a median of 14.1 months had passed since first symptoms; 427 patients (62.9%) were considered operable, 247 (36.4%) nonoperable, and 5 (0.7%) had no operability data; 386 patients (56.8%, ranging from 12.0%– 60.9% across countries) underwent surgery. Operable patients did not differ from nonoperable patients relative to symptoms, New York Heart Association class, and hemodynamics. A history of acute pulmonary embolism was reported for 74.8% of patients (77.5% operable, 70.0% nonoperable). Associated conditions included thrombophilic disorder in 31.9% (37.1% operable, 23.5% nonoperable) and splenectomy in 3.4% of patients (1.9% operable, 5.7% nonoperable). At the time of CTEPH diagnosis, 37.7% of patients initiated at least 1 pulmonary arterial hypertension–targeted therapy (28.3% operable, 53.8% nonoperable). Pulmonary endarterectomy was performed with a 4.7% documented mortality rate.

Conclusions—

Despite similarities in clinical presentation, operable and nonoperable CTEPH patients may have distinct associated medical conditions. Operability rates vary considerably across countries, and a substantial number of patients (operable and nonoperable) receive off-label pulmonary arterial hypertension–targeted treatments.

Evaluation and management of chronic pulmonary thromboembolic disease

Pulmonary embolism (PE) is common and the majority of patients survive the acute event. Survivors are at increased risk for adverse outcomes, including persistent thrombi, recurrent embolism, chronic thromboembolic pulmonary hypertension (CTEPH), and death. Anticoagulation protects against recurrence, which has a high mortality rate. The recommended duration of anticoagulation for patients with reversible PE risk factors is 3 months. For patients with idiopathic PE or persistent risk factors, extended duration of anticoagulation is preferred, balanced with an individual patient's risk of hemorrhage, which in itself is a major cause of morbidity and mortality. Among patients with malignancy who develop venous thromboembolism (VTE), low-molecular-weight heparin is preferred over oral vitamin K antagonists in the first 6 months. Thereafter, anticoagulation should be continued indefinitely with either low-molecular-weight heparin or oral vitamin K antagonists. Inferior vena cava filters are not routinely recommended and should only be used in patients who have a contraindication to anticoagulation. Patients who have had VTE and with persistent or recurrent dyspnea should be evaluated for recurrence of VTE or development of CTEPH. Patients with recurrent VTE should be anticoagulated indefinitely. Routine screening for CTEPH in asymptomatic patients is not recommended. Echocardiography often provides the first indication of the presence of pulmonary hypertension. Once presence of CTEPH is established by right-sided heart catheterization and perfusion imaging (ie, ventilation/perfusion scintigraphy, computed tomography angiography, or pulmonary angiography), patients should be referred early to a center with expertise, as it is potentially surgically curable by pulmonary endarterectomy. Those who are deemed inoperable after being evaluated may gain symptomatic benefit from drugs approved for idiopathic pulmonary arterial hypertension. Lung transplantation may also be an option for patients who are not candidates for pulmonary endarterectomy.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is one of the few forms of pulmonary hypertension that is surgically curable. It is likely underdiagnosed and must be considered in every patient presenting with pulmonary hypertension to avoid missing the opportunity to cure these patients. This article discusses the epidemiology, risk factors, natural history, diagnosis, and preoperative evaluation of patients with this disorder. Also covered are putative mechanisms for the conversion of acute emboli into fibrosed thrombembolic residua. Mechanical obstruction of the central pulmonary vasculature is rarely the sole cause of the pulmonary hypertension, and a discussion of the small vessel arteriopathy present in these patients is offered. Technical aspects of pulmonary endartectomy and the data supporting its role are discussed, as are the limited data on pulmonary arterial hypertension specific medical therapies for patients deemed noncandidates for the operation.

Methodology for ventilation/perfusion SPECT

Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices in all projections as well as in rotating volume images based upon maximum intensity projections. Probabilistic interpretation of V/Q SPECT should be replaced by a holistic interpretation strategy on the basis of all relevant information about the patient and all ventilation/perfusion patterns. PE is diagnosed when there is more than one subsegment showing a V/Q mismatch representing an anatomic lung unit. Apart from pulmonary embolism, other pathologies should be identified and reported, for example, obstructive disease, heart failure, and pneumonia. Pitfalls exist both with respect to imaging technique and scan interpretation.

Pulmonary thromboembolic disease. Clinical management of acute and chronic disease

Pulmonary thromboembolism falls between the areas of pulmonology and cardiology, internal medicine and intensive care, radiology and nuclear medicine, and hematology and cardiothoracic surgery. Depending on their clinical background, physicians faced with a patient with a pulmonary thromboembolism may speak different languages and adopt different treatment approaches. Now, however, there is an opportunity to end the Tower of Babel surrounding pulmonary thromboembolism. There is a growing acknowledgement that the key clinical problems in both acute pulmonary embolism and chronic thromboembolic pulmonary hypertension are linked to right ventricular pressure overload and right ventricular failure. As a result, cardiologists and cardiac intensive care specialists are taking an increasing interest in understanding and combating these conditions. The European Society of Cardiology was the first to elaborate comprehensive clinical practice guidelines for pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension. The task forces involved in producing these guidelines included radiologists, pulmonologists, hematologists, intensive care physicians and surgeons, which ensured that the final document was universally acceptable. The aim of this article was to provide an overview of the epidemiology, risk factors, diagnosis, treatment, prognosis and prevention of acute pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension, while taking into account European Society of Cardiology guidelines and incorporating new evidence where necessary.

Computed tomographic pulmonary angiography in the assessment of severity of chronic thromboembolic pulmonary hypertension and right ventricular dysfunction

PURPOSE

The aim was to investigate the role of computed tomographic pulmonary angiography (CTPA) in the assessment of severity and right ventricular function in chronic thromboembolic pulmonary hypertension (CTEPH).

MATERIALS AND METHODS

Clinical and radiological data of 56 patients with CTEPH January 2006-October 2009 were retrospectively reviewed in the present study. All patients received CTPA with a 64-row CT using the retrospective ECG-Gated mode before digital subtraction pulmonary angiography and right-heart catheterization. CTPA findings including Right Ventricular diameter (RVd) and left ventricular diameter (LVd) were measured at the end diastole. CT Pulmonary Artery Obstruction Indexes including Qanadli Index and Mastora Index were used in the assessment of severity of pulmonary arterial obstruction. Hemodynamic parameters and pulmonary hypertension classification were evaluated by right-heart catheterization in all patients. Right ventricular function was measured with echocardiography in 49 patients.

RESULTS

Qanadli Index and Mastora Index respectively were (37.93±14.74)% and (30.92±16.91)%, which showed a significant difference (Z=-5.983, P=0.000) and a good correlation (r=0.881, P=0.000). Neither Qanadli nor Mastora Index correlated with pulmonary hypertension classification (r=-0.009, P=0.920) or New York Heart Association heart function classification (r=-0.031, P=0.756). Neither Qanadli nor Mastora Index correlated with any echocardiographic right ventricular parameters (P>0.05), while RVd/LVd by CTPA correlated with echocardiographic right ventricular functional parameters (P<0.05). Both Qanadli (r=-0.288, P=0.006) and Mastora Index (r=-0.203, P=0.032) demonstrated a weakly negative correlation with SPO2. CTPA findings correlated with hemodynamic variables. Backward linear regression analysis revealed that the RVd/LVd, Right Ventricular Anterior Wall Thickness (RVAWT), Main Pulmonary Artery trunk diameter (MPAd) were shown to be independently associated with mean Pulmonary Artery Pressure (mPAP) levels (model: r2=0.351, P=0.025; RVd/LVd: beta=11.812, P=0.000; RVAWT: beta=2.426, P=0.000; MPAd: beta=0.677, P=0.003).

CONCLUSION

Computed tomographic pulmonary angiography is a valuable tool to evaluate hemodynamics, right ventricular function of CTEPH, but neither Qanadli Index nor Mastora Index can reflect pulmonary arterial obstruction in CTEPH accurately.

Pulmonary MR angiography techniques and applications

This article discusses the role of magnetic resonance angiography (MRA) in evaluating the pulmonary arterial system. For depiction of pulmonary arterial anatomy and morphology, MRA techniques are compared with CT angiography and digital subtraction x-ray angiography. Perfusion, flow, and function are emphasized, as the integrated MR examination offers a comprehensive assessment of vascular morphology and function. Advances in MR technology that improve spatial and temporal resolution and compensate for potential artifacts are reviewed as they pertain to pulmonary MRA. Current and emerging gadolinium contrast-enhanced and non-contrast-enhanced MRA techniques are discussed. The role of pulmonary MRA, clinical protocols, imaging findings, and interpretation pitfalls are reviewed for clinical indications.

Brain natriuretic peptide as a preclinical marker of chronic pulmonary hypertension in patients with pulmonary embolism

Chronic thromboembolic pulmonary hypertension (CTPH) is a potential complication of pulmonary embolism (PE). Only few studies have assessed the role of brain natriuretic peptide (BNP) in patients with chronic pulmonary hypertension, and there are no data on the potential utility of BNP as a preclinical biomarker of CTPH. To assess the correlation between pulmonary artery systolic pressures (PAPs) and amino terminal proBNP (Nt-proBNP) and its value in the diagnosis of CTPH in patients with previous PE. Patients were evaluated with echocardiography at least 6 months after the index event. Pulmonary hypertension was defined as PAPs > or =40 mmHg at rest. Each subject underwent measurement of Nt-proBNP. Forty-nine patients were enrolled (mean age 64.5 +/- 13.1 years; 22 men). Seven patients had CTPH, and two were symptomatic. There was a good correlation between PAP on echocardiography and Nt-proBNP (r 0.64; P = 0.00003). Nt-proBNP was elevated in 6 of 7 patients [sensitivity: 85.7%; 95% confidence interval (CI): 48.7, 97.4] and it was normal in 35 of 42 patients without CTPH (specificity: 76.2%; 95% CI: 61.5, 86.5%). Six of the 13 patients with high Nt-proBNP levels had CTPH, whereas 1 of 36 patients with normal Nt-proBNP levels had pulmonary hypertension. The resulting positive predictive value was 46.1% (95% CI: 19.2, 74.9), and the negative predictive value was 97.2% (95% CI: 85.5-99.9). In conclusion, Nt-proBNP correlates with PAPs and may be used to exclude preclinical or symptomatic CTPH in patients with previous PE. Prospective studies on a larger population are warranted to confirm our preliminary findings.

Chronic thromboembolic pulmonary hypertension: an updated review

PURPOSE OF REVIEW

Venous thromboembolism is a spectrum of disease comprising deep vein thrombosis, thrombus in transit, acute pulmonary embolism, and chronic thromboembolic pulmonary hypertension (CTEPH) as a rare and late possible sequela.

RECENT FINDINGS

On the basis of a prospective long-term study, the incidence of CTEPH is estimated at 3.8% within 2 years of all patients surviving an episode of symptomatic idiopathic pulmonary embolism. Young age, a large perfusion defect, and idiopathic clinical presentation are associated with a higher probability of CTEPH. Current pathophysiological concepts suggest a misguided thrombus resolution process that is triggered by infection, inflammation, autoimmunity, and malignancy. Diagnosis and therapy of CTEPH are interdisciplinary achievements and nowadays still based on a positive lung perfusion scan and for assessment of operability on a classical pulmonary angiography. Treatment of choice is surgical pulmonary endarterectomy of the pulmonary obstructions, which leads to restoration of normal pulmonary hemodynamics at rest in nearly 80% of patients. In expert centers, surgical mortality is under 10%.

SUMMARY

CTEPH has emerged as a 'dual' pulmonary vascular disorder with major vessel vascular remodeling of thrombus organization, combined with a small vessel pulmonary arteriopathy that is a target for classic vasodilator treatments.

Thromboendarterectomy for severe chronic thromboembolic pulmonary hypertension

Pulmonary thromboendarterectomy is a curative surgical procedure for chronic thromboembolic pulmonary hypertension. The aim of this study was to clarify whether severe hemodynamic compromise affects surgical outcome. We studied 19 patients who underwent pulmonary thromboendarterectomy and compared 11 with pulmonary vascular resistance < 1,000 dyne x s x cm(-5) (group 1) and 8 with pulmonary vascular resistance > 1,000 dyne x s x cm(-5) (group 2). Mean pulmonary artery pressure and pulmonary vascular resistance decreased significantly after surgery in both groups. The incidence of postoperative complications did not differ between groups; however, one patient in group 2 died of multiorgan failure. The overall mortality rate was 5.3%, and the rate in group 2 was 13%. Our results indicate that preoperative hemodynamic compromise does not affect surgical outcome. Patients with high pulmonary vascular resistance can be treated effectively by thromboendarterectomy, with acceptable morbidity and mortality.

Acute improved hemodynamics following inhaled iloprost in chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potential consequence to pulmonary embolism. The histologic picture is similar to idiopathic pulmonary hypertension (IPAH) suggesting that vascular remodeling also contributes to CTEPH. The treatment of choice is pulmonary endarterectomy. However, this treatment option is not adequate for all patients with CTEPH. Currently, no data exist on standard vasodilative therapy for CTEPH. Intravenous and oral prostanoids, both well-known vasodilators in IPAH, have been used with promising results, whereas the same has not been consistently observed for inhaled iloprost.

OBJECTIVE

In this study, we examined acute hemodynamic effects of inhaled iloprost in patients with CTEPH.

METHODS

In a prospective study, right heart catheterization was performed in 20 patients (mean age 56 years, New York Heart Association class II-IV) at the time of diagnosis of CTEPH. Pulmonary vascular resistance (PVR), mean pulmonary arterial pressure (mPAP), cardiac output (CO), mean systemic arterial pressure (MAP) and oxygen partial pressure (PaO(2)) were obtained before and 20 min after inhaling 5 mug iloprost. Subsequently, all patients were evaluated for pulmonary endarterectomy. Six patients were eligible for surgery.

RESULTS

Significant changes in pulmonary and systemic hemodynamics were observed following the inhalation of iloprost (before to after inhalation): PVR: 1,057 +/- 404.3 to 821.3 +/- 294.3 dyn.s.cm(-5), p < 0.0001; mPAP: 50.55 +/- 8.43 to 45.75 +/- 8.09 mm Hg, p = 0.0002; CO: 3.66 +/- 1.05 to 4.05 +/- 0.91 l/min, p < 0.0106. MAP and PaO(2) decreased significantly (MAP: 94.15 +/- 11.58 to 89.45 +/- 14.29 mm Hg, p = 0.0111; PaO(2): 7.33 +/- 1.17 to 6.64 +/- 1.25 kPa, p = 0.0260).

CONCLUSIONS

Hemodynamic changes directly following inhalation of iloprost suggest a significant contribution of a reversible component of vasoconstriction to pulmonary arterial hypertension in patients with CTEPH.

Evaluation of Persistent Pulmonary Hypertension After Acute Pulmonary Embolism

BACKGROUND

Better knowledge of the evolution of persistent pulmonary hypertension after acute pulmonary embolism (PE) is required to optimize the indication and timing of pulmonary endarterectomy (PEA).

METHODS

We reviewed our experience with 17 consecutive patients demonstrated to have persistent pulmonary hypertension after acute massive (n = 1), submassive (n = 7), or recurrent PE (n = 9).

RESULTS

After a median of 18 weeks of anticoagulation (range, 12 to 30 weeks) since the last PE, 10 patients showed residual pulmonary artery systolic pressure (PAsP) > 50 mm Hg. These patients demonstrated a significant progression in PAsP over the ensuing 6 to 12 months, from 73 +/- 14 to 101 +/- 26 mm Hg (p = 0.005) [mean +/- SD], and eight patients were found to be suitable candidates for PEA. In contrast, among seven patients with residual PAsP from 35 to 40 mm Hg (n = 3) and 41 to 50 mm Hg (n = 4), six patients had evidence of residual perfusion defects on the ventilation/perfusion scan and CT. The PAsP did not change significantly over the ensuing 6 to 12 months, except in two patients who had new episodes of acute PE.

CONCLUSIONS

Two groups of patients can be identified based on the degree of residual pulmonary hypertension after acute PE. Patients with residual PAsP > 50 mm Hg should be evaluated for PEA since their pulmonary artery pressures will significantly progress over the ensuing 6 to 12 months despite the absence of recurrent PE. In contrast, patients with PAsP from 35 to 50 mm Hg are at risk for severe pulmonary hypertension if new PE occurs, and should therefore be closely monitored.