Chronic Thromboembolic Pulmonary Hypertension (CTEPH) arises from unresolved Pulmonary Embolism (PE), a condition where blood clots, typically travelling from deep veins in the legs, become lodged in the lung arteries. When these blood clots fail to dissolve, they eventually transform into scar tissue which obstruct blood flow, forcing the right side of the heart to work harder, leading to shortness of breath and, in severe cases, right heart failure.
Key Risk Factors for CTEPH:
Several factors can increase an individual's risk of developing CTEPH. These include:
History of Pulmonary Embolisms
Prolonged Immobility such as following surgery or illness.
Chronic inflammatory conditions
Antiphospholipid Syndrome, a condition that increases the risk of forming blood clots within arteries
Genetic Predisposition: Certain genetic disorders that can increase blood clotting tendencies such as non-O blood groups.
Other Factors: Chronic heart and lung conditions, splenectomy, hypothyroidism, and presence of ventriculoatrial shunts or indwelling catheters. Immobility and obesity can further accelerate the risk.
Diagnosis of CTEPH:
Diagnosing CTEPH can be challenging as its symptoms often mimic other conditions. The diagnostic process typically begins with evaluating symptoms in individuals with a history of deep vein thrombosis or pulmonary embolism. Initial tests include a six-minute walk test and an echocardiogram. The definitive diagnostic tool is a Ventilation-Perfusion (VQ) Scan, which assesses ventilation and perfusion in the lungs; mismatches on this scan are highly indicative of CTEPH.
Pulmonary Endarterectomy (PEA): The Gold Standard Treatment:
Pulmonary endarterectomy (PEA) is considered the gold standard and potentially curative treatment for CTEPH. This complex surgical procedure involves the meticulous removal of chronic scar tissue from within the pulmonary arteries, aiming to restore normal blood flow. While PEA can cure the condition, patients will require lifelong blood-thinning medication.
Suitability for PEA Surgery:
PEA is a major open-chest procedure. Patients must meet specific criteria for eligibility, including a confirmed CTEPH diagnosis via several imaging modalities, most often with a V/Q scan, high-resolution CT scan, pulmonary angiogram, and right heart catheterization. The latter permits accurate measurement of the exact pressure within the lung arteries. Patients must also be free of other significant health conditions that would preclude major surgery.
Alternatives to Surgery:
For patients who are not suitable candidates for PEA surgery, alternative treatments exist:
Medical Therapy: Vasodilating drugs like Riociguat can be used, though their effectiveness may be limited in the long-term
Balloon Pulmonary Angioplasty (BPA): This procedure shows promise in some regions, especially Japan, but is often very expensive and not widely available outside of clinical trials.
Complexity of PEA Surgery and Post-Operative Care:
PEA surgery is exceptionally complex due to the need to operate far within the pulmonary arteries. The procedure involves specialized instruments and periods of deep hypothermic circulatory arrest, requiring strict time limits and protection of the brain and heart. Post-operatively, a small number of patients may need ECMO support for a few days to aid lung and heart recovery. Typical hospital stays are under two weeks for patients with good pre-operative health, though those with more severe conditions may require longer ICU time.
Multidisciplinary Approach and Center Expertise:
Successful CTEPH treatment, especially surgery, necessitates a multidisciplinary team approach in hospitals with expertise in advanced lung disease. Specialized radiologists are crucial for accurate diagnosis and providing surgeons with a clear roadmap of the disease. Choosing high-volume centers with established expertise, specialized nursing, and allied healthcare staff significantly improves patient outcomes and reduces mortality rates.
Risks and Long-term Management:
Like any major surgery, PEA carries risks such as bleeding, kidney damage, heart attack, and infection. A specific risk is reperfusion injury, an inflammatory response in the lungs when blood supply is restored. Mortality rates at high-volume centers should be well below 5%.
Long-term management after PEA involves lifelong blood-thinning medication and lifestyle adjustments such as weight management and regular exercise. Strict follow-up for at least the first year is essential, including repeat studies to assess improvements in both pulmonary artery pressures, and functional capacity.
Future Outlook and Public Awareness:
There is a pressing need for greater identification and timely diagnosis of CTEPH patients, especially in regions where awareness about the condition remains limited. Many patients are referred late with advanced symptoms simply because early signs are overlooked or mistaken for other illnesses. Future efforts should focus on increasing awareness among both healthcare providers and the public, training more specialists, and ensuring that individuals with a history of pulmonary embolism who develop new or worsening symptoms are promptly referred to specialized pulmonary hypertension centers for accurate diagnosis and effective care.
Advice for Loved Ones:
Loved ones play a crucial role in early detection. Be vigilant for symptoms in patients, especially those over 55-60, who might attribute changes to aging. Watch for a quick decline in walking speed, inability to climb stairs, unexplained shortness of breath, coughing without exertion, swollen calves, or leg pain. These symptoms warrant immediate medical attention to facilitate early diagnosis and intervention, which can significantly improve outcomes for CTEPH patients.
Dr. Kumud Kumar Dhital
Senior Consultant Cardiothoracic Surgeon, Program & Surgical Director – Institutes of Heart-Lung Transplant and MCS
Apollo Hospitals, Chennai