Chronic Thromboembolic Pulmonary Hypertension Medical Management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a common long-term complication of pulmonary embolism characterized by thromboembolic obstruction of the pulmonary arteries, vascular arteriopathy, vascular remodeling, and ultimately pulmonary hypertension (PH). Although pulmonary endarterectomy (PEA) surgery is the standard of care, approximately 40% of patients in the international CTEPH registry were deemed inoperable. In addition to lifelong anticoagulation, the cornerstone of PH-specific medical management is riociguat, a soluble guanylate cyclase stimulator. Medical management should be started early in CTEPH patients and may be used as a bridge to PEA surgery or balloon pulmonary angiography. Medical management is indicated for inoperable CTEPH patients and patients who have recurrence of PH after PEA surgery.     

Pulmonary microvascular disease in chronic thromboembolic pulmonary hypertension

Distal, small-vessel vasculopathy is generally considered a major contributor to the progression of pulmonary hypertension (PH) as chronic thromboembolic pulmonary hypertension (CTEPH) develops over time and is a major determinant of postoperative outcome after pulmonary endarterectomy (PEA). The pathogenesis and natural history of microvascular disease in CTEPH remain uncharacterized. Mechanisms for significant distal disease may involve the following processes: (1) predominant obstructions of "small" subsegmental elastic pulmonary arteries, (2) classical pulmonary arteriopathy of small muscular arteries and arterioles distal to nonobstructed vessels, (3) pulmonary arteriopathy of small muscular arteries and arterioles distal to totally or partially obstructed vessels. Patients in whom obstructed vessels are mainly subsegmental are considered poor surgical candidates. Distal pulmonary vasculopathy in both the occluded and nonoccluded pulmonary vascular bed is characterized by lesions considered typical for idiopathic pulmonary arterial hypertension, including plexiform lesions. The pathogenesis and time course of these vascular lesions remain unclear, but may involve endothelial and/or platelet production and release of mediators and/or altered pulmonary blood flow. The reciprocal contribution of large-vessel (operable) and small-vessel lesions in CTEPH is crucial for the indication and results of PEA. A combination of investigations is used to identify the extent of small-vessel disease, including right-heart catheterization, perfusion lung scan, multidetector spiral computed tomography, pulmonary angiography, and pulmonary arterial occlusion wave-form analysis. Preliminary evidence suggests that medical therapy may provide hemodynamic and clinical benefits for patients in whom PEA cannot be applied, in those who have persistent postoperative PH, or in selected patients with advanced preoperative hemodynamic changes.     

Update on chronic thromboembolic pulmonary hypertension

Chronic, unresolved thromboemboli are an important cause of pulmonary hypertension (PH) with specific treatment strategies differing from other types of PH. Chronic thromboembolic pulmonary hypertension (CTEPH) is classified as group 4 PH by the World Health Organization. It is a rare, but underdiagnosed, complication of acute pulmonary embolism that does not resolve and results in occlusion of large pulmonary arteries with a fibro-thrombotic material. The etiology of CTEPH remains uncertain, and it is unknown why certain patients with acute pulmonary embolism develop this disorder. The evaluation for CTEPH is an important part of the evaluation for PH in general, and it is crucial not to overlook this diagnosis, as it is the only form of PH that is potentially curable. Patients diagnosed with CTEPH should be referred to an expert center for consideration of pulmonary endarterectomy, and surgical removal of the chronic thromboembolic material. Not all patients with CTEPH are surgical candidates, however, and there are emerging treatments—medical therapy and balloon pulmonary angioplasty—that have shown benefit in this patient population. Without treatment, CTEPH can lead to progressive pulmonary vascular obstruction, right heart failure, and death. Thus, it is important for clinicians to recognize this subtype of PH. In this review, we provide an overview of current understanding of the pathogenesis of CTEPH and highlight recommendations and recent advances in the evaluation and treatment of CTEPH.     

核素肺显像在慢性血栓栓塞性肺动脉高压诊断和定量评价的应用

目的评价放射性核素肺灌注／通气（Q／V）显像在慢性血栓栓塞性肺动脉高压（CTEPH）诊断和定量评价中的价值。方法78例肺动脉高压住院患者，经超声心动图排除了瓣膜性心脏病和先天性心脏病引起的肺动脉高压，且既往无急性肺栓塞病史。所有患者均接受Q／V显像，并以肺动脉造影确诊，分别计算Q／V显像对CTEPH的诊断敏感性、特异性和准确性。对肺动脉造影确诊为CTEPH患者的肺灌注显像进行定量分析，计算全肺灌注缺损百分数（PPDs％），并对PPDs％分别与平均肺动脉压（mPAP）、肺动脉收缩压（SPAP）进行相关性分析，并进行统计学检验。结果以高度可能分级作为CTEPH的诊断标准，Q／V显像的诊断敏感性、特异性和准确率分别为96．0％，81．1％和86．9％；而如果将高度和中度可能分级均作为CTEPH的判断依据，则分别为100％，69．8％和79．5％。PPDs％与mPAP和SPAP均具有直线相关性，PPDs％与mPAP，r=0．538，P〈0．01；PPDs％与SPAP，r=0．456，P〈0．05。结论Q／V显像是CTEPH诊断和定量评价的有价值的无创性影像学方法。     

The efficacy of bosentan in inoperable chronic thromboembolic pulmonary hypertension: a 1-year follow-up study.

The treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary endarterectomy (PEA). However, many patients develop a severe progressive small vessel pulmonary arteriopathy that is inaccessible to surgical intervention and is associated with poor survival. The purpose of the present study was to evaluate the medium-term efficacy and safety of the dual endothelin receptor antagonist, bosentan, in inoperable CTEPH. Forty-seven patients with inoperable CTEPH (distal disease or persistent pulmonary hypertension following PEA) underwent evaluation after 1 yr of bosentan therapy. Outcomes included assessment of 6-min walk test (6MWT), haemodynamics and World Health Organization functional classification. Monitoring of serious adverse effects and changes in therapy was undertaken. Patients showed sustained improvements in 6MWT (49+/-8 m), functional classification, cardiac index (+0.2+/-0.07 L.min(-1).m(-2)) and total pulmonary resistance (-139+/-42 dyn.s.cm(-5)). Those patients with persisting pulmonary hypertension following PEA showed the greatest improvement. One-yr survival was 96%, and bosentan was well tolerated with only one patient developing deranged liver function. Although all patients with chronic thromboembolic pulmonary hypertension should be considered for pulmonary endarterectomy, bosentan provides an alternative medical therapy to improve function and delay the progression of this devastating disease in those in whom surgery is not suitable.     

Multiparametric Magnetic Resonance Imaging in the Assessment of Pulmonary Hypertension: Initial Experience of a One-Stop Study

Introduction

Our goal was to assess the diagnostic performance of magnetic resonance imaging (MRI) as a single method to diagnose pulmonary hypertension (PH) compared to right heart catheterization (RHC), computed tomography (CT), and ventilation/perfusion (V/Q) scintigraphy.

Methods

We identified 35 patients diagnosed with PH by RHC in our institution who have also undergone a CT, a scintigraphy, and an MRI within a month. All cases were discussed in multidisciplinary meetings. We performed correlations between the MRI-derived hemodynamic parameters and those from RHC. The sensitivity and specificity of MRI were determined to identify its diagnostic performance to identify chronic thromboembolic pulmonary hypertension (CTEPH) and interstitial lung disease PH. The gold standard reference for the diagnosis of CTEPH and ILD was based on a review of multimodality imaging (V/Q scintigraphy and CT scan) and clinical findings.

Results

Our results showed a good correlation between the hemodynamic parameters of cardiac MRI and RHC. Pulmonary vascular resistance had the best correlation between both methods (r?=?0.923). The sensitivity and specificity of MRI to diagnose CTEPH was 100 and 96.8%, respectively. For the ILD-related PH, the MRI yielded a sensitivity of 60.0% and a specificity of 100%. Additionally, cardiac MRI was able to confirm all cases of PAH due to congenital heart disease initially detected by echocardiography.

Conclusions

MRI represents a promising imaging modality as an initial, single-shot study, for patients with suspected PH with the advantages of being non-invasive and having no radiation exposure.

     

Resolutive pulmonary endarterectomy in a non-compliant patient with systemic lupus erythematosus and antiphospholipid syndrome

Patients with chronic thromboembolic pulmonary hypertension (CTEPH) have poor prognosis, and pulmonary endarterectomy (PEA) is considered the treatment of choice for this condition. We report a case and review the literature of successful PEA for CTEPH due to antiphospholipid syndrome associated with systemic lupus erythematosus. The definitive and decisive approach needed to treat this high-risk patient with a history of comorbidity, long-term illness and poor compliance was found with a therapy of PEA.     

State-of-the-art imaging techniques in chronic thromboembolic pulmonary hypertension

It is important to differentiate chronic thromboembolic pulmonary hypertension (CTEPH) from other forms of pulmonary hypertension (PH) to target treatment and optimize therapeutic outcome. Misdiagnosis is common, and high-quality imaging is essential if CTEPH is to be diagnosed correctly. In addition to making a diagnosis, imaging helps identify patients for surgery, aids surgical planning, and provides postsurgical monitoring. Ventilation-perfusion scintigraphy and pulmonary angiography have been the mainstay of diagnosis and surgical assessment for many years, but cross-sectional techniques are rapidly taking over. Echocardiography is used to confirm or refute the presence of PH and to identify cardiac causes if PH is present. For patients with PH but no evidence of cardiac disease, multislice computed tomography (CT) is the next best step. CT distinguishes CTEPH from idiopathic arterial PH, evaluates underlying lung disease, and may help identify rarer causes of PH. CT is quick, widely available, and inexpensive. There is, however, a significant radiation burden, and it is unsuitable for serial examinations. Magnetic resonance (MR) involves no ionizing radiation and makes an ideal alternative. When combined with techniques for measuring ventricular function and blood flow, MR provides unique insight into structure and function. CT and MR are complementary techniques, and together they represent the future of imaging in PH. How they might be used in routine clinical practice is presented as a diagnostic algorithm developed at Papworth Hospital, the United Kingdom's national center for surgical treatment of CTEPH.     

Riociguat: A Novel Therapeutic Option for Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are serious and often fatal diseases. The pathophysiology of both diseases is complex and in part is attributed to alterations in the nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate pathway. Riociguat, a novel sGC stimulator, acts on this pathway through a dual mechanism of action by directly stimulating sGC in a NO-independent manner and also increasing the sensitivity of sGC to NO. Based on benefits from clinical trials for both PAH and CTEPH, riociguat was approved by Health Canada and the US Food and Drug Administration as the first medical therapy for patients with CTEPH who are deemed inoperable or have residual/recurrent PH after pulmonary endarterectomy (PEA), and as a novel treatment option for patients with PAH. This article reviews the key findings from the phase III trials for riociguat that led to these approvals and the implications this has for the treatment of patients with PAH and CTEPH.     

Therapie der chronischen Thromboembolie (CTEPH)

Chronic thromboembolic pulmonary hypertension (CTEPH) is a frequent cause of pulmonary hypertension, however, it still is underdiagnosed. Up to 4% of all individuals that survive pulmonary embolism develop CTEPH. Increasing insights into the pathophysiology of CTEPH indicate a distinct overlap with pulmonary arterial hypertension (PAH). Pulmonary endarterectomy (PEA), which lowers pulmonary resistance and can lead to normalization of hemodynamics, is the treatment of choice for eligible patients, however, only a proportion of patients fulfill the criteria for surgical intervention. Patients who are not eligible for PEA may benefit from specific medical therapy for pulmonary hypertension, as do patients before and after PEA with significant peripheral involvement of the pulmonary vasculature. Direct evidence from clinical trials in CTEPH is promising, but is to date limited. Further studies are necessary to define criteria for specific medical therapy for CTEPH.     

Assessment of operability in chronic thromboembolic pulmonary hypertension

Pulmonary endarterectomy surgery (PEA) offers the possibility of a cure for patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH). Despite growing experience worldwide, the approach and criteria for patient selection remain variable and center- or expert-dependent. A significant proportion of patients with CTEPH may be turned down for PEA for a number of reasons, most frequently over concerns of distal or inaccessible disease. Although traditional preoperative testing and currently available tools are adequate in identifying the presence of proximal disease in CTEPH, they provide only limited information on the status of the microvasculature. Because persistent pulmonary hypertension is the most important determinant of post-PEA outcome, the preoperative identification of patients with CTEPH with concomitant small-vessel disease and/or microvascular disease is crucial. Pulmonary vascular resistance (PVR) is a useful parameter for assessing potential concomitant small-vessel disease. By assessing the relative contribution of small vessels to the PVR, the pulmonary artery occlusion technique represents a promising tool for determining the risk of surgery in patients with high PVR. More information is required regarding the potential value or risk of preoperative medical therapies. Although traditional surgical classification of CTEPH takes place intraoperatively, there is a need for a preoperative classification system and consensus on operability. A preliminary preoperative classification system has been proposed.     

Rechtsherzversagen bei chronischer pulmonaler Hypertonie und akuter Lungenembolie

Right-sided heart failure is a severe and often life-threatening complication of chronic pulmonary hypertension. The detection of trigger factors that induce right heart failure in previously stable patients is important to initiate a causal therapeutic strategy. Pulmonary embolism (PE) is a frequent cause of acute right heart failure and therapeutic strategies for PE are well documented in the current guidelines. Treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH) is surgical pulmonary endarterectomy (PEA) and patients with possible CTEPH should be referred to an experienced PEA surgeon without delay. Intensive care management for overt right heart failure is complex and includes the use of pulmonary vasodilators, individual adjustment of diuretic or volume therapy, augmentation of myocardial contractility and left ventricular afterload. Therapeutic regimens aim at optimized filling of the right ventricle, improvement of myocardial perfusion by avoiding tachycardia, elevating systemic pressure and reducing right ventricular afterload. Early communication with a specialized center for pulmonary hypertension is recommended.     

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) should be differentiated from other etiologies of pulmonary hypertension since surgical intervention may be potentially curative. The presentation of this illness is nonspecific and may mimic other cardiopulmonary disease states. Without treatment, progressive pulmonary hypertension, right heart failure, and death will ensue. Echocardiography, lung ventilation-perfusion scan, right heart catheterization, and angiography are required for proper diagnosis and preoperative assessment. Definitive treatment requires surgical resection of thromboembolic material. The role of medical therapy remains to be defined.     

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potentially life-threatening condition characterized by obstruction of pulmonary arterial vasculature by acute or recurrent thromboemboli with subsequent organization, leading to progressive pulmonary hypertension and right heart failure. Until relatively recently, CTEPH was a diagnosis made primarily at autopsy, but advances made in diagnostic modalities and surgical pulmonary endarterectomy techniques have made this disease treatable and even potentially curable. Although published guidelines are available, in the absence of randomized controlled trials regarding CTEPH there is a lack of standardization, and treatment options have to be individualized.     

Incidence and risk factors of chronic thromboembolic pulmonary hypertension in patients after acute pulmonary embolism

Background

Early identification and treatment of chronic thromboembolic pulmonary hypertension (CTEPH) are critical to prevent disease progression. We determined the incidence and risk factors for CTEPH in patients with a first episode of acute pulmonary embolism (PE).

Methods

In this study, consecutive patients with first-episode acute PE were followed for ≤5 years. Pulmonary hypertension (PH) was screened for by echocardiography. Suspected cases were evaluated by right heart catheterization (RHC) and pulmonary angiography (PA). If invasive procedures were not permitted, PH was diagnosed by systolic pulmonary artery pressure (SPAP) >50 mmHg. Diagnosis of CTEPH was confirmed by PA, ventilation/perfusion (V/Q) lung scan, or computed tomography (CT) PA (CTPA).

Results

Overall, 614 patients with acute PE were included (median follow-up, 3.3 years). Ten patients were diagnosed with CTEPH: cumulative incidence 0.8% [95% confidence interval (CI), 0.0-1.6%] at 1 year, 1.3% (95% CI, 0.3-2.3%) at 2 years, and 1.7% (95% CI, 0.7-2.7%) at 3 years. No cases of CTEPH developed after 3 years. History of lower-limb varicose veins [hazard ratio (HR), 4.3; 95% CI, 1.2-15.4; P=0.024], SPAP >50 mmHg at initial PE episode (HR, 23.5; 95% CI, 2.7-207.6; P=0.005), intermediate-risk PE (HR, 1.2; 95% CI, 1.0-1.4; P=0.030), and CT obstruction index over 30% at 3 months after acute PE (HR, 42.5; 95% CI, 4.4-409.8; P=0.001) were associated with increased risk of CTEPH.

Conclusions

CTEPH was not rare after acute PE in this Chinese population, especially within 3 years of diagnosis. Lower-limb varicose veins, intermediate-risk PE with elevated SPAP in the acute phase, and residual emboli during follow-up might increase the risk of CTEPH.     

Kommentar zu den 2015 ESC/ERS-Leitlinien zur Diagnostik und Therapie der pulmonalen Hypertonie

Pulmonary hypertension (PH) is a common phenomenon, which – independently from the underlying cause – is associated with a reduced life expectancy. Recently published landmark studies have led to substantial progress in the management of PH, particularly pulmonary arterial hypertension (PAH), and provided the basis for the updated recommendations of the 2015 joint guidelines of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS) on the diagnosis and treatment of pulmonary hypertension. The updated version includes important modifications with regards to hemodynamic definitions and the clinical classification of PH. Furthermore, the recommendations and algorithms for the diagnostic assessment of patients with suspected PH, risk stratification and treatment of PAH were profoundly modified, introducing novel drugs and the establishment of improved treatment strategies, such as combination therapy. Finally, the new ESC/ERS guidelines provide formal recommendations for the management of other forms of PH, such as PH due to left heart or chronic lung disease and chronic thromboembolic pulmonary hypertension, and define criteria for specialized PH expert centres. This comment focusses on the most important changes compared to the previous version of the ESC/ERS guidelines published in 2009 and on the practical implementation of the new guidelines in Germany.     

Pulmonary hypertension in Switzerland: treatment and clinical course

BACKGROUND: The prognosis of pulmonary hypertension (PH), especially idiopathic pulmonary arterial hypertension (IPAH), has improved during the recent years. The Swiss Registry for PH represents the collaboration of the various centres in Switzerland dealing with PH and serves as an important tool in quality control. The objective of the study was to describe the treatment and clinical course of this orphan disease in Switzerland. METHODS: We analyzed data from 222 of 252 adult patients, who were included in the registry between January 1999 and December 2004 and suffered from either PAH, PH associated with lung diseases or chronic thromboembolic PH (CTEPH) with respect to the following data: NYHA class, six-minute walking distance (6-MWD), haemodynamics, treatments and survival. RESULTS: If compared with the calculated expected figures the one, two and three year mean survivals in IPAH increased from 67% to 89%, from 55% to 78% and from 46% to 73%, respectively. Most patients (90%) were on oral or inhaled therapy and only 10 patients necessitated lung transplantation. Even though pulmonary endarterectomy (PEA) was performed in only 7 patients during this time, the survival in our CTEPH cohort improved compared with literature data and seems to approach outcomes usually seen after PEA. The 6-MWD increased maximally by 52 m and 59 m in IPAH and CTEPH, respectively, but in the long term returned to or below baseline values, despite the increasing use of multiple specific drugs (overall in 51% of IPAH and 29% of CTEPH). CONCLUSION: Our national registry data indicate that the overall survival of IPAH and presumably CTEPH seems to have improved in Switzerland. Although the 6-MWD improved transiently, it decreased in the long term despite specific and increasingly combined drug treatment. Our findings herewith underscore the progressive nature of the diseases and the need for further intense research in the field.     

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

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

Recent progress in the diagnosis and management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension caused by non-resolving thromboembolisms of the pulmonary arteries. In Japan, in contrast to Western countries, CTEPH is more prevalent in women. A Japanese multicenter study reported that a form of CTEPH unrelated to deep vein thrombosis is associated with HLA-B?5201, suggesting that this form of CTEPH may be associated with vasculopathy. CTEPH can be cured by pulmonary endarterectomy, provided that the thrombi are surgically accessible; thus, early diagnosis is important, and all patients with exertional dyspnea should be evaluated for pulmonary hypertension. Ventilation/perfusion scans provide an excellent non-invasive means to distinguish CTEPH from pulmonary arterial hypertension. Similarly, computed tomographic pulmonary angiograms allow for the detection of thrombi and evaluation of pulmonary hemodynamics in a minimally invasive manner. Importantly, the absence of subpleural perfusion on pulmonary angiograms can suggest the presence of small vessel disease. Small vessel disease might be involved in the pathogenesis of CTEPH, and its detection is essential in preventing operative death. Although no modern therapies for pulmonary arterial hypertension have been approved for treatment of CTEPH, a recent randomized control trial of riociguat in patients with CTEPH demonstrated that riociguat significantly improved 6-min walking distance. Further investigations into treatments that target endothelial dysfunction and hyperproliferative CTEPH cells are needed. Recently, balloon pulmonary angioplasty has emerged as a promising treatment modality in Japan. A specialized medical team, including at least one expert surgeon, should make decisions regarding patients' candidacy for pulmonary endarterectomy and/or balloon pulmonary angioplasty.     

Histopathological multiple recanalized lesion is critical element of outcome after pulmonary thromboendarterectomy

Pulmonary thromboendarterectomy (PEA) is a curative therapy for chronic thromboembolic pulmonary hypertension (CTEPH), but the postoperative mortality remains unsatisfactory (4-10%). Residual pulmonary hypertension is the most common cause of perioperative death. Although PEA specimens seem to contain lesions responsible for hemodynamic improvement, relevant histopathological findings have still to be identified.The aim of this study was to identify histopathological findings that predict postoperative residual pulmonary hypertension after PEA.PEA specimens obtained from 51 consecutive patients with CTEPH were histopathologically assessed. The patient characteristics and disease location were reviewed by medical records. The associations with residual pulmonary hypertension were analyzed.The mean values of preoperative and postoperative vascular resistance (PVR) were 1142 ± 454 and 496 ± 368 dynes?sec/cm(-5), respectively. Twenty of 51 patients (39%), including 2 patients who died, continued to have residual pulmonary hypertension (PVR ≥ 500 dynes?sec/cm(-5)). Statistical tests indicated that male, proximal disease type and the presence of histopathological multiple recanalized thrombus were associated with good surgical outcome (PVR < 500 dynes?sec/cm(-5)). The positive and negative predictive values for surgical outcome estimated by the presence of multiple recanalized lesions were higher than the values estimated by proximal disease type (85% and 88% versus 73% and 71%, respectively). Moreover, the number of multiple recanalize lesions was significantly correlated to the reduction in PVR (P = 0.03).The presence of histopathological multiple recanalized lesions was significantly associated with a decrease in PVR after PEA. Histopathological study may be a potent diagnostic strategy for accurately predicting surgical outcome in the early perioperative period.