In general, patients complain of progressive dyspnea, particularly on exertion, together with hemopstysis, fatigue, syncope, palpitations or edema (all signs of right heart failure) [3]. Schistosomiasis can have an acute and chronic course. A severe inflammatory reaction to the parasite that causes nocturnal fever, headaches, dyspnea and myalgia in the setting of acute disease (also known as Katayama syndrome), whereas an asthma-like disease is seen in chronic forms [4]. In both acute and chronic disease, pulmonary vascular disease and cor pulmonale (right heart failure) may develop and lead to CTEPH [4].

• Fatigue

  Dyspnea and fatigue were the most common presenting symptoms. History of pulmonary embolism was present in 82%. Of patients, 18 (67%) were assessed as operable, of whom 10 (55%) finally underwent pulmonary endarterectomy (PEA). [ncbi.nlm.nih.gov]

  or near fainting. 4) class IV: symptoms at rest (such as dyspnea and/or fatigue) and inability to carry out any physical activity without symptoms (e.g. may faint especially while bending over with their heads lowered). [clinicaltrials.gov]

  Symptoms of CTEPH are progressive dyspnea, hemoptysis and right-heart failure signs such as fatigue, weakness and edema. Additional complaints depend on the underlying cause. [symptoma.com]

  The commonest presenting symptoms are dyspnea, reduced exercise tolerance and fatigue, common to a range of cardiopulmonary diseases which result in a diagnosis of CTEPH frequently being delayed. [minervamedica.it]

  Changes in the pulmonary arteries restrict blood flow, leading to a rise in blood pressure. 2,3 The most common symptoms of CTEPH are similar to those of PH, including shortness of breath with exercise, fatigue, or weakness. [cteph.com]

• Weakness

  Being short of breath, especially during exercise Feeling tired Feeling weak Feeling pain or pounding in the chest (the pounding is called palpitations) Swelling of the legs due to fluid retention ( edema ) Developing cyanosis (blue color to fingers and [my.clevelandclinic.org]

  Changes in the pulmonary arteries restrict blood flow, leading to a rise in blood pressure. 2,3 The most common symptoms of CTEPH are similar to those of PH, including shortness of breath with exercise, fatigue, or weakness. [cteph.com]

  Symptoms of CTEPH are progressive dyspnea, hemoptysis and right-heart failure signs such as fatigue, weakness and edema. Additional complaints depend on the underlying cause. [symptoma.com]

  Baseline PVR>1000 dynes.s.cm −5 was a weak predictor of 1-, and 3- year survival (Fisher's exact test p=0.05, p=0.06). [doi.org]

• Fever

  It causes fever with inflammation in multiple organs starting shortly after birth. Infants present with symptoms of infection (e.g., fever, rash) but no infection is found. The rash resembles hives. [rheumatology.org]

  For e.g. schistosomiasis is manifested by nocturnal fever and malaise several weeks after exposure to contaminated waters in endemic areas (the Caribbean island, Brazil, China, the Middle east and sub-Saharan Africa). [symptoma.com]

  The recurrent flares of inflammatory symptoms along with the recurrent fevers led to these syndromes being classified as periodic fever syndromes before the genetic origins were discovered. [autoinflammatory.org]

  As in all forms of CAPS, symptoms include skin rash, fever and inflammation of the eyes. The symptoms of NOMID/CINCA tend to be constant, rather than episodic, with intermittent flares in activity. [dermnetnz.org]

  TNF-receptor associated periodic fever (TRAPS) usually present with long lasting fever episodes followed by clinical remission. [ojrd.biomedcentral.com]

• Chest Discomfort

  We describe the case of a 40-year-old male with unexplained severe pulmonary arterial hypertension with a seven-day history of progressive shortness of breath, hemoptysis, chest discomfort and bilateral pedal edema. [ncbi.nlm.nih.gov]

  Other symptoms include: Chest discomfort Light-headedness Fainting Coughing up blood Swelling in the legs Palpitations CTEPH diagnosis Correctly diagnosing CTEPH is essential, as the underlying cause of pulmonary hypertension can have a huge impact on [pulmonaryhypertensionnews.com]

• Exposure to Contaminated Water

  For e.g. schistosomiasis is manifested by nocturnal fever and malaise several weeks after exposure to contaminated waters in endemic areas (the Caribbean island, Brazil, China, the Middle east and sub-Saharan Africa). [symptoma.com]

• Dyspnea

  The Borg dyspnea index rates the severity of dyspnea (difficult or labored breathing) on a scale from 0 ('Nothing at all') to 10 ('Very, very severe - maximal'). A decrease in the Borg dyspnea index indicates an improvement. [clinicaltrials.gov]

  CTEPH must be suspected in any patient with NS, with or without hyperhomocysteinemia, and unexplained dyspnea. [ncbi.nlm.nih.gov]

  The Borg score, on the other hand, is a patient reported quantitative scaling method of the symptomatic dyspnea. Patients rate their own dyspnea on a scale from 0 (no dyspnea) to 10 (absolutely breathlessness) ( Borg, 1982 ). [intechopen.com]

• Hemoptysis

  A systematic review revealed 21 studies on the underlying pathology in 1,844 patients with moderate to severe hemoptysis. [ncbi.nlm.nih.gov]

• Exertional Dyspnea

  A 35-year-old man with a six-month history of progressive exertional dyspnea was referred to our institution. [ncbi.nlm.nih.gov]

  Chronic thromboembolic pulmonary hypertension (CTEPH), an underappreciated cause of severe pulmonary arterial hypertension (PAH), usually presents with progressive exertional dyspnea. [mayoclinic.org]

  Also, plausible alternative diagnoses for dyspnea were confirmed in all 10 patients who reported exertional dyspnea but did not visit our outpatient clinic. [haematologica.org]

  Patients with CTEPH typically present with exertional dyspnea but do not show severely disturbed resting hemodynamics at early stages. [karger.com]

  Procedures Patients who had otherwise unexplained persistent dyspnea on exertion or at rest during follow-up were considered to have thromboembolic pulmonary hypertension. [doi.org]

• Pleural Effusion

  We report CTEPH in a 58-year-old male who had pleurisy with a small haemorrhagic pleural effusion three months ago. The six-month course of anti-coagulation therapy failed to resolve thromboemboli completely or improve pulmonary hypertension. [ncbi.nlm.nih.gov]

  Imaging studies such as plain chest radiography may show enlarged pulmonary trunk, hypertrophy of the right ventricle and pleural effusions, which may be confirmed by echocardiography, a widely recommended procedure for CTEPH evaluation. [symptoma.com]

  effusion#, pharyngolaryngeal pain, pharyngitis Pleuritic pain, pulmonary fibrosis, pulmonary hypertension, pulmonary haemorrhage da Ordningens eller den individuelle støttes varighed en Prophylactic use of Pedea in the first # days of life (starting [da.glosbe.com]

  Complications include haemoptysis, wire injury, vessel dissection, vessel rupture, reperfusion pulmonary oedema, pulmonary parenchymal bleeding and haemorrhagic pleural effusions. [doi.org]

• Tachypnea

  Newborns that have PPHN have rapid respiration (tachypnea) and abnormal bluish discoloration of the skin due to low levels of circulating oxygen in the blood (cyanosis). [rarediseases.org]

  Severity Index (PESI) was validated in large populations of patients with PE 99,100 and found capable of identifying patients with very low rates of adverse events. 101 The index considers such factors like age, sex, comorbidities, presence of tachycardia, tachypnea [revespcardiol.org]

• Heart Failure

  The factors that affect patient QoL 1 year after surgery on some SF-36 subscales included the presence of coronary artery disease, COPD, heart failure, residual pulmonary hypertension, and prolonged ventilation, neurological complications in the early [ncbi.nlm.nih.gov]

  In both acute and chronic disease, pulmonary vascular disease and cor pulmonale (right heart failure) may develop and lead to CTEPH. [symptoma.com]

• Chest Pain

  A 29-year-old man presented with chest pain, decreased exercise capacity, dyspnoea, and haemoptysis. He was triple positive for antiphospholipid antibodies. [ncbi.nlm.nih.gov]

  As the disease progresses, other symptoms may appear, including: difficulty breathing water retention in the limbs (edema) swelling or bloating of the abdomen chest pain light-headedness We use advanced diagnostic testing to determine whether patients [brighamandwomens.org]

  If left untreated, CTEPH can cause fatigue, chest pain, and shortness of breath. In later stages, CTEPH can cause fainting and heart failure symptoms. [healthcare.utah.edu]

  pain Fatigue Palpitations Edema, or fluid collection in the legs or abdomen Fainting Diagnostics Right-heart catheterization Echocardiogram Ventilation-perfusion scan (VQ scan) Pulmonary angiogram – shows blood flow through the lungs Pulmonary function [houstonmethodist.org]

  Other frequent symptoms were chest pain and syncope. Both groups were similar in chest radiographs, electrocardiograph, pulmonary function test, and echocardiograph results. [ndsl.kr]

• Palpitations

  Being short of breath, especially during exercise Feeling tired Feeling weak Feeling pain or pounding in the chest (the pounding is called palpitations) Swelling of the legs due to fluid retention ( edema ) Developing cyanosis (blue color to fingers and [my.clevelandclinic.org]

  In general, patients complain of progressive dyspnea, particularly on exertion, together with hemopstysis, fatigue, syncope, palpitations or edema (all signs of right heart failure). Schistosomiasis can have an acute and chronic course. [symptoma.com]

  […] and heart disease Some surgeries such as hip or knee replacement Bone fractures Family or personal blood clot history Spleen removal Long-term use of intravenous catheters, including those for dialysis Symptoms Shortness of breath Chest pain Fatigue Palpitations [houstonmethodist.org]

  Other symptoms include: Chest discomfort Light-headedness Fainting Coughing up blood Swelling in the legs Palpitations CTEPH diagnosis Correctly diagnosing CTEPH is essential, as the underlying cause of pulmonary hypertension can have a huge impact on [pulmonaryhypertensionnews.com]

  The most common symptoms of CTEPH include: Fatigue Shortness of breath, especially with exercise Less common symptoms include: Chest pain Heart palpitations or fluttering Dry cough Swelling of the lower extremities or stomach (edema) As the disease progresses [upmc.com]

• Cyanosis

  Being short of breath, especially during exercise Feeling tired Feeling weak Feeling pain or pounding in the chest (the pounding is called palpitations) Swelling of the legs due to fluid retention ( edema ) Developing cyanosis (blue color to fingers and [my.clevelandclinic.org]

  Individuals with advanced stages of PAH may have abnormal bluish discoloration of the skin due to low levels of circulating oxygen in the blood (cyanosis). [rarediseases.org]

  As the disease progresses, additional signs of right heart failure from PAH can be detected with jugular venous distention, right-sided S3, hepatomegaly, ascites, lower extremity edema, and peripheral cyanosis. [thecardiologyadvisor.com]

• Jugular Venous Distention

  As the disease progresses, additional signs of right heart failure from PAH can be detected with jugular venous distention, right-sided S3, hepatomegaly, ascites, lower extremity edema, and peripheral cyanosis. [thecardiologyadvisor.com]

  Physical examination often reveals signs of right heart failure including jugular venous distention, hepatomegaly, ascites, and peripheral edema. 1 Bruits may be appreciated on auscultation of the peripheral lung fields. [anesthesiology.pubs.asahq.org]

• Hepatomegaly

  By the time of presentation to the ED, he was noted to be hypoxaemic and had clinical signs of right heart dysfunction (tender hepatomegaly and elevated jugular venous pressure) without dependent oedema. [hindawi.com]

  […] from Baseline of at least 20 percent in the distance walked during the six-minute walk test; an increase of one or more WHO functional class; worsening right ventricular failure (e.g., as indicated by increased jugular venous pressure; new/worsening hepatomegaly [clinicaltrials.gov]

  As the disease progresses, additional signs of right heart failure from PAH can be detected with jugular venous distention, right-sided S3, hepatomegaly, ascites, lower extremity edema, and peripheral cyanosis. [thecardiologyadvisor.com]

  Physical examination often reveals signs of right heart failure including jugular venous distention, hepatomegaly, ascites, and peripheral edema. 1 Bruits may be appreciated on auscultation of the peripheral lung fields. [anesthesiology.pubs.asahq.org]

  As RV failure progresses, jugular venous distension, peripheral edema, hepatomegaly and ascites may become evident. Pulmonary flow murmurs, representing turbulent flow across narrowed pulmonary vessels, are rarely observed 51. [onlinelibrary.wiley.com]

• Hepatosplenomegaly

  […] retinal vasculitis – rare Physical appearance Prominent forehead Flattening of the nasal bridge (saddleback nose) Large head (macrocephaly) – 95% Large fontanelle Short stature Short thick extremeties Finger clubbing Other Liver and spleen enlargement (hepatosplenomegaly [dermnetnz.org]

  Any evidence of right heart failure such as the presence of jugular venous distention, right-sided S3, hepatosplenomegaly, ascites, or peripheral edema may indicate severe pulmonary hypertension and deserve more urgent attention. [thecardiologyadvisor.com]

• Myalgia

  A severe inflammatory reaction to the parasite that causes nocturnal fever, headaches, dyspnea and myalgia in the setting of acute disease (also known as Katayama syndrome), whereas an asthma-like disease is seen in chronic forms. [symptoma.com]

  […] consider pharmacoeconomic implications, patients that take tadalafil would pay two-thirds of the cost of sildenafil therapy.[75] However, there are some adverse effects of this drug such as headache, diarrhea, nausea, back pain, dyspepsia, flushing and myalgia [en.wikipedia.org]

• Microscopic Hematuria

  Proteinuria and microscopic hematuria also disappeared. Encouragingly, RA and RV dilation, and the pulmonary arterial pressure almost returned to a normal range half a year later, with alleviation of MR. [ncbi.nlm.nih.gov]

• Headache

  Discussion Headache in a patient on warfarin can be an ominous symptom and requires careful assessment including an INR level, CT scan, and full neurological exam. Delay in diagnosis can be catastrophic. [jtd.amegroups.com]

  Headache. Swollen feet and legs. Untreated, CTEPH gets worse and can be fatal. What can you do to help relieve symptoms of chronic thromboembolic pulmonary hypertension (CTEPH)? Pay attention to your body, and do not overdo it. [my.clevelandclinic.org]

  In Muckle-Wells syndrome (MWS), patients develop episodic fever, chills, rash, red eyes, joint pain, and severe headaches, often after exposure to cold. Episodes last from one to three days. [rheumatology.org]

  The most common AEs reported were dyspepsia, headache and hypotension [42]. [err.ersjournals.com]

  Periodic Fevers & Flare-ups Often, NOMID syndrome causes bouts of fevers (starting in infancy), accompanied by flare-ups of the rash, increased pain in the joints, headaches, red eyes and other symptoms. [autoinflammatory.org]

• Dizziness

  Stop if you get dizzy or short of breath. Follow a low-salt diet as recommended by your healthcare provider. Follow any dietary needs that might go along with your blood-thinner medication. [my.clevelandclinic.org]

  […] of breath, especially with exercise Less common symptoms include: Chest pain Heart palpitations or fluttering Dry cough Swelling of the lower extremities or stomach (edema) As the disease progresses, symptoms of light-headedness or exercise-related dizziness [upmc.com]

  The most frequently occurring adverse events in the riociguat arm were headache, dizziness, dyspepsia, peripheral oedema and nasopharyngitis (table 2). [err.ersjournals.com]

  AEs were mainly mild to moderate in nature and the most common were headache and dizziness. [doi.org]

  […] diseases, including: Asthma Emphysema Chronic obstructive pulmonary disease (COPD) Obesity (overweight) Heart failure Common symptoms include: Shortness of breath, especially with exercise or climbing stairs Fatigue (tiredness) Swelling of the legs Dizziness [foundation.chestnet.org]

• Vertigo

  The most frequent adverse events in the bosentan arm were peripheral oedema, abnormal liver function test, headache, right ventricular failure, nasopharyngitis, vertigo and palpitations (table 2). [err.ersjournals.com]

A thorough patient history may provide vital clues about the underlying cause, for e.g.recent travel to endemic areas for schistosomiasis and exposure to potentially contaminated waters approximately 2-12 weeks prior to the appearance of symptoms [4]. A meticulous physical examination with an emphasis on cardiopulmonary auscultation is equally important. Namely, distended neck veins, ascites, edema and tricuspid regurgitation may reflect right heart failure, whereas peripheral pulmonary bruits (very rare but highly specific for CTEPH) may be observed in approximately 10% of patients [3]. Imaging studies such as plain chest radiography may show enlarged pulmonary trunk, hypertrophy of the right ventricle and pleural effusions [4], which may be confirmed by echocardiography, a widely recommended procedure for CTEPH evaluation [3]. MRI and CT are also frequently used, but ventilation/perfusion (V/Q) lung scintigraphy may show segmental perfusion defects and for this reason, it is considered as the optimal diagnostic procedure [16]. Pulmonary angiography is equally effective in visualizing the level of obstruction and vessel narrowing [9]. In most patients CTEPH is distinguished from PAH by presence of thrombi in major pulmonary vessels, but virtually any part of the circulation may be affected [12]. Apart from their role in diagnosis, these procedures are important in evaluating the possibility of endarterectomy [9].

• Right Axis Deviation

  The electrocardiogram demonstrates findings of right ventricular hypertrophy (right axis deviation, dominant R-wave in V1). [phaonlineuniv.org]

  Electrocardiography Right axis deviation and precordial T wave abnormalities are early signs. Pulmonary function tests Elevated pulmonary artery pressure causes restrictive physiology. [slideplayer.com]

  Electrocardiogram may reveal right axis deviation, right ventricular hypertrophy, and a right bundle-branch block. [anesthesiology.pubs.asahq.org]

  ECG signs of right heart strain include P-pulmonale, right bundle branch block, T-wave abnormalities in the chest leads and right-axis deviation [ 11 – 13 ]. [err.ersjournals.com]

  […] chest leads and right-axis deviation are indications of right heart strain [1, 47, 48]. [smw.ch]

• Decreased Platelet Count

  Platelet transfusions may further decrease platelet count, as it can trigger formation of new antibodies. [ncbi.nlm.nih.gov]

• Oxygen Saturation Decreased

  If oxygen saturation decreases, arterial pressure is adjusted or vasoactive drugs (e.g. dehydrobenzperidole or papverine) to avoid cerebral vessel spasm are administered; (3) on the left side, the proximal left pulmonary artery is completely transsected [academic.oup.com]

• Right Ventricular Hypertrophy

  An echocardiogram showed severe pulmonary hypertension and right ventricular hypertrophy, and contrast-enhanced chest CT revealed multiple thromboemboli within both pulmonary arteries. [ncbi.nlm.nih.gov]

  In the setting of right ventricular hypertrophy, perfusion of the right ventricle is limited to diastole and dependent on diastolic blood pressure similar to left ventricular coronary perfusion. [anesthesiology.pubs.asahq.org]

  The electrocardiogram demonstrates findings of right ventricular hypertrophy (right axis deviation, dominant R-wave in V1). [phaonlineuniv.org]

  The transthoracic echocardiogram showed dilatation of the right heart chambers (right atrial area of 22 cm 2 and right ventricular end-diastolic diameter of 44 mm), right ventricular wall hypertrophy (10 mm), right ventricular dysfunction (right myocardial [revportcardiol.org]

• Pleural Effusion

  We report CTEPH in a 58-year-old male who had pleurisy with a small haemorrhagic pleural effusion three months ago. The six-month course of anti-coagulation therapy failed to resolve thromboemboli completely or improve pulmonary hypertension. [ncbi.nlm.nih.gov]

  Imaging studies such as plain chest radiography may show enlarged pulmonary trunk, hypertrophy of the right ventricle and pleural effusions, which may be confirmed by echocardiography, a widely recommended procedure for CTEPH evaluation. [symptoma.com]

  effusion#, pharyngolaryngeal pain, pharyngitis Pleuritic pain, pulmonary fibrosis, pulmonary hypertension, pulmonary haemorrhage da Ordningens eller den individuelle støttes varighed en Prophylactic use of Pedea in the first # days of life (starting [da.glosbe.com]

  Complications include haemoptysis, wire injury, vessel dissection, vessel rupture, reperfusion pulmonary oedema, pulmonary parenchymal bleeding and haemorrhagic pleural effusions. [doi.org]

Several therapeutic strategies exist for management of CTEPH. Pulmonary endarterectomy is a surgical procedure that provides curative effects in many patients (since it enables complete removal of emboli from the occluded vessels) and is now considered as the mainstay of therapy [5]. But because of its characteristics (profound hypothermia, cardiopulmonary bypass and induced cardiac arrest), a mortality rate of 4.4% during surgery is observed [14]. Moreover, it may not be performed in all patients (presence of additional comorbidities, location of emboli in smaller vessels and poor overall condition). It may also be unsuccessful in patients with significant arteriopathy of smaller vessels, which is why alternative interventions are advocated. Anticoagulant therapy, prostanoids, endothelin receptor antagonists, or phosphodiesterase-5-inhibitors are pharmacological agents most frequently used in these patients, but their efficacy requires further research [17]. As a last resort, lung transplantation may be performed [17].

If CTEPH is left untreated, the estimated survival is about three years [1]. Moreover, the majority of patients are diagnosed in advanced stages of the disease [1], when little can be done in terms of treatment, which is why an early diagnosis is detrimental.

Several conditions have been associated with PAH in literature, including Schistosomiasis (caused by a nematode worm Schistosoma mansoni, S. hematobium or S.japonicum) [7], idiopathic pulmonary arterial hypertension (IPAH), anorexigen exposure and sleep apnea [1] [8]. In all diseases, CTEPH stems from occlusion of pulmonary vessels by thromboemboli that generate increased pressure and resistance. Pulmonary embolism (PE) is, in fact, the condition that predisposes patients to CTEPH, which may develop in any of the mentioned conditions through various pathophysiological mechanisms. However, why do these emboli persist after months or even years remains unclear. Current studies have determined that some patients possess clotting factor aberrations, but in the majority of patients, the exact mechanism is yet to be determined [9].

Studies have determined that CTEPH develops in approximately 4,000 individuals in the United States every year [1], whereas overall incidence rates after pulmonary embolism are up to 3%-4% after 2 years [2] [6]. PE is, by far, the most significant risk factor for CTEPH as approximately 50% of patients report acute pulmonary thromboembolism in their recent history [10]. Schistosomiasis is an infection affecting more than 200 million individuals over the world, but its prevalence is highest in developing countries and certain geographical areas [7]. The Caribbean countries, the eastern part of South America (Brazil), sub-Saharan Africa, China and the Middle east are considered to be endemic regions of this parasite and travel to these areas is considered as an important risk factor [4]. Approximately 8% of individuals suffering from this disease develop PAH [7], but other reports suggest that the prevalence of PAH is as high as 20% [4]. For unknown reasons, CTEPH is more frequently encountered in females [1]. An additional risk factor is the presence of lupus anticoagulant [11], an antibody against phospholipids that promotes coagulation [11], while splenectomy, ventriculoatrial shunts, inflammatory bowel disease and osteomyelitis have also been determined as conditions that increase the susceptibility toward CTEPH [12].

Although the exact model of disease in CTEPH is incompletely understood, current theories implicate various etiologic factors that impair the coagulatory cascade [13]. Numerous diseases have been described as potential triggers of pulmonary arterial hypertension, defined as mean pressure in the pulmonary artery ≥ 25 mmHg at rest or > 30 mmHg during exercise [1]. In virtually all patients, the predisposing condition that leads to CTEPH is pulmonary embolism, in which formation of a thrombus occludes pulmonary vessels and causes increased pressure. Usually, the thrombus dissolves completely, but in some individuals, this process is not carried out in full [14]. The exact mechanism remains unknown, but it is established that up to 10% of patients have some abnormality of the coagulation system, such as protein C or S deficiency and impairment of the fibrin clotting system [14]. Procoagulatory states in the setting of increased factor VIII values were identified as well [15]. Additionally, some patients develop repetitive pulmonary embolism, which further contributes to persistence of clots in the pulmonary vasculature [14]. In the setting of schistosomiasis, the life cycle of the parasite starts by shedding from the initial host (local population) through feces and urine into water, infection of various snail species and subsequent invasion of human hosts through breaks in the skin [4]. Once the parasite spreads through the lymphatic system and into the lungs, it replicates and disseminates throughout the gastrointestinal tract and the liver, eventually forming an embolus in many blood vessels, including pulmonary arteries [4]. Regardless of the pathophysiological mechanism, the end-result in CTEH is remodeling of the emboli that narrows or obstructs the major arteries of the pulmonary system, leading to dysfunction of the right ventricle and increased pulmonary vascular resistance, eventually causing cardiac insufficiency [10].

Although prevention of venous thromboembolism through management of the underlying disease may be a prudent strategy, studies have determined that more than 60% of CTEPH patients do not exhibit any symptoms suggestive of venous disease [6]. For this reason, wide-scale use of echocardiography may be highly effective as a tool for an early diagnosis, especially in the setting of known schistosomiasis infection [7]. Additionally, long-term monitoring and prophylaxis of patients who developed pulmonary embolism and increased awareness of possible CTEPH is detrimental for prevention [2].

Chronic thromboembolic pulmonary hypertension (CTEPH) is defined as persistent pulmonary arterial hypertension (PAH) for three consecutive months after an episode of pulmonary thromboembolism [1]. Although CTEPH is a rarely encountered phenomenon in clinical practice, it is often unrecognized and associated with a substantial risk of mortality [2]. Numerous diseases are known to cause PAH and thus predispose to CTEPH, including schistosomiasis, sleep apnea, exposure to anorexigen (an appetite suppressant) and various collagenoses [1], whereas idiopathic pulmonary arterial hypertension (IPAH) is also an important cause. In the presence of these conditions, intraluminal organization of a thrombus and concomitant stenosis as a result of fibrous tissue accumulation leads to increased resistance in the pulmonary vasculature [3]. In an attempt to overcome this adverse circulatory event, the right ventricle enlarges and increases its contractile force, but because the vessel lumen is persistently narrowed or completely occluded, failure of the right heart eventually ensues [3]. Symptoms of CTEPH are progressive dyspnea, hemoptysis and right-heart failure signs such as fatigue, weakness and edema [3]. Additional complaints depend on the underlying cause. For e.g. schistosomiasis is manifested by nocturnal fever and malaise several weeks after exposure to contaminated waters in endemic areas (the Caribbean island, Brazil, China, the Middle east and sub-Saharan Africa) [4]. To make the diagnosis, a thorough approach consisting of a properly obtained patient history and a detailed physical examination is vital. Initial signs of heart failure (tricuspid regurgitation, distended neck veins, or ascites) are important clinical findings that can guide the physician toward the diagnosis [3], which is confirmed by various imaging studies. Plain radiography, echocardiography, computed tomography (CT), magnetic resonance imaging (MRI), lung scintigraphy and angiography are all indicated when CTEPH is suspected, to solidify the diagnosis and to determine the optimal therapeutic strategy.The procedure of choice (when possible) is pulmonary endarterectomy (PEA), comprising of surgical removal of emboli from pulmonary vessels. Despite a small, but significant risk of death during surgery (4.4%), this procedure has curative effects in the vast majority of patients and can profoundly improve the quality of life [5]. If CTEPH is left untreated, the disease is universally fatal within a few years, which is why an early diagnosis must be made. This may be difficult, however, as more than 60% of patients show no symptoms of previous thromboembolic disease [6], implying the necessity for more detailed regular check-ups and conduction of screening strategies.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a condition that develops due to narrowing and obstruction of blood vessels in the lungs, most commonly following pulmonary embolism (PE), where a blood clot gets "stuck" in one or more vessels. Because clots block the passage of blood, the heart generates higher pressures to overcome this obstacle, leading to increased pressure inside the blood vessels of the lungs, medically known as pulmonary hypertension (PAH). For yet unknown reasons, CTEPH develops months or even years after the initial episode of PE and factors that promote incomplete resolution of the clot are yet to be discovered. In addition to PE, conditions such as sleep apnea, schistosomiasis (a parasitic infection), exposure to anorexigen (a suppressant of appetite) and idiopathic pulmonary hypertension (IPAH) are known causes of CTEPH. It is estimated that approximately 4,000 cases develop in the United States every year and a strong predilection toward female gender was established. Risk factors that promote coagulatory states (and thus impair resolution of previously formed blood clots) include osteomyelitis, inflammatory bowel disease (IBD), presence of ventriculoatrial shunts and spleen removal. The diagnosis may be attained with great difficulty, as many patients report no obvious signs of thromboembolic disease. Progressive heavy breathing (dyspnea), coughing of blood (hemoptysis) and symptoms that reflect failure of the right side of the heart due to prolonged efforts to combat blood vessel occlusion, such as fatigue, malaise, palpitations and syncope are most frequently encountered. Imaging studies, including plain chest X-ray, computed tomography (CT scan), magnetic resonance imaging (MRI) and echocardiography are all useful in solidifying the diagnosis, but the two most important procedures are CT-guided angiography and lung scintigraphy, which allow direct visualization of blood flow through the lungs and identification of the exact site of occlusion. This is quite important, as the optimal therapeutic strategy is surgical removal of clots from the occluded arteries, known as pulmonary endarterectomy. Because this type of surgery mandates cessation of heart function and marked reduction of body temperature (as low as 20 degrees Celsius), a very small number of patients (around 4%) do not survive this procedure, but its efficacy that may even result in complete cure significantly outweighs the risks. An early diagnosis is essential for patients sufferning from CTEPH, primarily to obtain a much better prognosis, as the condition is fatal within a few years if left untreated.

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