CTEPH diagnosis is challenging

• CTEPH’s common symptoms—progressive dyspnea on exertion, rapid exhaustion, fatigue—and its clinical course can be indistinguishable from other forms of severe PH.¹⁵
  • If symptoms, signs, and history suggest PH, patients should be urgently referred for further assessments.

• Patients with CTEPH can present without a history of PE, but studies vary widely in their estimates of what proportion such patients represent.^8,15
  • In 2004, Lang reported that of 142 consecutive CTEPH patients, 90 (63%) had no history of acute PE.¹⁶
  • Conversely, data reported in 2011 from a European registry, which included 679 patients, showed that 74.8% of CTEPH patients did have a history of acute PE.⁸
• CTEPH can progress quickly, though some patients may experience a “honeymoon period” of some months to several years between their acute PE and clinical signs of CTEPH.¹⁵
  • Signs of right-heart failure occur late in the course of the disease.¹⁵

Using “SCAR” for diagnosis and treatment of CTEPH

The broad approach to diagnosis and treatment of CTEPH can be described by a simple mnemonic, “SCAR”³:

CTPA, computed tomography pulmonary angiogram; MRA, magnetic resonance angiogram; V/Q, ventilation/perfusion.

• Echocardiography is used in the initial assessment of suspected PH.¹⁸
• According to the Fifth World Symposium on Pulmonary Hypertension, held in 2013 in Nice, France, the V/Q scan is the preferred and recommended screening test for CTEPH.³
  • A diagnosis of CTEPH may be confirmed by the presence of a mismatched wedge-shaped perfusion defect.¹⁸
  • Diagnosis of CTEPH can be supported by characteristic findings during multislice CT angiography, including a mosaic perfusion pattern, dilatation of proximal pulmonary arteries and right heart chambers, and the presence of vascular stenosis or obstruction.¹⁸
• Right heart catheterization is used for hemodynamic evaluation to confirm the presence of PH and to provide prognostic information.¹⁸
• Referral to specialized centers for testing to define anatomical locations and extent of obstructions and to quantify the degree of PH is essential.¹
• The sequence of these tests may vary according to the factors suggestive of PH.¹⁹

PTE is the primary treatment for CTEPH.

Because pulmonary thromboendarterectomy* (PTE) is potentially curative, it is the primary treatment for patients with CTEPH.³

Not every patient is a candidate for surgery, though.

In a European CTEPH registry of 679 patients, published in 2011, 247 (36.6%) were deemed to have inoperable disease.⁸

The most common reason patients in this registry were considered to have inoperable disease was because the lesions were considered too distal or inaccessible.⁸

• Inaccessibility of occlusions, n=118/247
• Comorbidities, n=33/247
• Imbalance between increased pulmonary vascular resistance (PVR) and amount of accessible occlusions, n=25/247
• PVR>1500 dyn∙s∙cm^-5, n=6/247
• Age, n=5/247
• Other, n=56/247
• Patients missing data, n=4/247

Every patient diagnosed with CTEPH should be evaluated by an expert CTEPH team, including CTEPH physicians and PTE surgeons, to assess their candidacy for PTE surgery.³

PTE operability assessment is an inherently subjective exercise, and it depends very much on the experience and the skills of the CTEPH team and the PTE surgeon. Whenever feasible, seek an assessment from a second experienced CTEPH team if a patient is initially deemed to have inoperable disease.³

However, surgery or operability assessments are not the only referrals that should be made for patients with CTEPH. V/Q scan referrals are recommended for the early signs of CTEPH to ensure patients are properly diagnosed from the start.³

Get information about patients with inoperable or recurrent CTEPH.

*Also called pulmonary endarterectomy or PEA.

Following PTE, patients must be closely monitored and reassessed regularly

• Up to one-third of patients may have residual CTEPH following PTE.*²⁵

CTEPH is often misdiagnosed due to nonspecific symptoms and variable disease course²

• V/Q scans, which are >96% sensitive for detecting CTEPH and which effectively rule out CTEPH when negative, are underutilized in screening PH patients.^3,23
• A US registry of patients (N=786) who had been diagnosed with PAH revealed that 43% had been diagnosed with PAH despite never having received a V/Q scan to screen for CTEPH.³⁰
  • In approximately one-third of these cases without a V/Q scan, the healthcare provider, when asked why a V/Q scan was not performed, answered that it was not relevant.³⁰

Consider reassessing PAH patients who have not received a V/Q scan to see if they have potentially operable, potentially curable CTEPH.

Because pulmonary thromboendarterectomy* (PTE) is potentially curative, it is the primary treatment for patients with CTEPH.³

• A V/Q scan is an important diagnostic test for patients with suspected PH or PE patients who are still symptomatic after 3 months of anticoagulation.⁶

If a V/Q scan suggests CTEPH³, the patient should be referred to a specialized center with expertise in the treatment of this condition.