Bronchial Thermoplasty treatment for severe, persistent Asthma

Summary

Bronchial Thermoplasty is a non-invasive procedure to treat patients who suffer from persistent, and severe form of asthma. This form of asthma is marked by a swelling of the smooth muscle that lines the airways in the lungs, which constricts the airways. This procedure aims to shrink these muscles and thereby open up the airways. Although relatively new, it is very effective and has tremendous benefits. In this article, we will learn more.

Introduction to Asthma

Asthma is a complex lung disorder in which, airways of the lungs get inflamed, become overactive (called airway hyperresponsiveness or AHR) and show constriction. Since asthma has been around for a long time, there have been several advances in clinical and pharmaceutical research around the condition. This has led to very effective treatments and detailed information that is shared on how to manage the disease effectively.

In spite of this, around 5-10% of adults, worldwide, grapple with severe, persistent asthma. This is the fourth category of asthma based on severity, the other three being mild intermittent, mild persistent and moderate persistent. Unlike other patients who suffer from mild to moderate symptoms and an occasional asthma attack, those with severe, persistent asthma (also called ‘difficult to treat asthma’) have repeated attacks and severe symptoms.

Treating such patients becomes a frustrating exercise for both the physicians and patient alike. These patients require three or four different asthma medicines along with long-term administration of oral corticosteroids. These steroids come with their own side-effects; hence it becomes necessary to develop alternative therapies.

Such patients account for an unusually large percentage of asthma-related morbidity and mortality. They persistently experience severe symptoms, which sometimes includes life-threatening attacks. The socio-economic impact of such patients is also high – in terms of healthcare costs and the cost of missed days at school or work.

What is Bronchial Thermoplasty?

One of the symptoms of severe, persistent asthma is a near-total blockage of the airways in the lungs. This happens due to two reasons. One is the excess accumulation of mucous inside the airways, and second is the swelling of the Airway Smooth Muscle (ASM) that lines these airways. The ASM is a thin ring of muscle that holds the airway. In patients with asthma, this ring of muscles is thicker than that of a person without asthma. In patients with severe, persistent asthma, they are even thicker, which constricts the airway severely, leading to serious attacks.

Bronchial Thermoplasty (BT) is a non-invasive procedure that addresses the second problem, of the ASM becoming thick. In BT, heat (thermal treatment) is provided to shrink the soft tissue in the ASM. As the ASM shrinks, the airways open out, relieving the person of asthma symptoms. This is a permanent change, which means, subsequent to BT, the ASM cannot become thick ever again. This offers hope to millions of people who suffer from severe, persistent asthma.

Whom is it done for?

BT is not for everyone. The ideal candidate must fulfil the following conditions. A qualified pulmonologist (lung specialist) will take a call on whether BT can be done or not.

• The person has asthma attacks that cannot be controlled by steroid-based inhalers, beta-agonists or long-acting bronchodilator medications
• The person needs oral steroids to control his/her asthma
• The person is in the age-group of 18 to 65 years
• He/she has not smoked in the last 1 year
• The condition has severely affected his/her professional/academic and personal lives
• Is not allergic to medicines used in bronchoscopy
• Does not have an internal defibrillator, pacemaker, or other implantable electronic devices for the heart

How is BT done?

A full course of BT therapy includes three separate sessions of bronchoscopy, spread three weeks apart. The three sessions separately target the left lower lobe of the lungs, the right lower lobe, and the two upper lobes in the last session. The sessions are outpatient procedures which means the patient is discharged the same day, every time. In some cases, the patient is discharged the next morning. To minimize discomfort to the patient, the procedure is done under local anaesthesia with a mild sedative given to the patient.

Once the patient is sedated, a bronchoscope, which is a long, thin and flexible tube is pushed gently into the patient’s nose or mouth all the way into the desired lobe of the lungs, and close to the airways. A catheter which is a thin tube with a camera, light and instruments fitted at the tip are introduced into the bronchoscope, all the way to the airways. In this case, the catheter carries a RF device at its tip.

The RF device is made to emit a series of 10-second, temperature-controlled bursts of radio frequency waves. These waves heat up the lining of the lungs to 65 degrees Celsius. Given that the ASM is made of soft tissue, this heat shrinks the swollen-up ASM permanently, thereby opening up the airways. The doctor is viewing the progress continuously on a monitor that displays images relayed by the camera.

Once he/she is satisfied, the catheter is pulled out of the bronchoscope, after which the bronchoscope is also pulled out. Once the effect of the sedative and anaesthesia wears off, the patient is observed closely for a couple of hours. Once all vitals are stable, the patient is discharged.

Benefits

In a double-blind, randomized, sham-controlled, clinical study on BT, adults with severe asthma treated by BT showed the following benefits:

• Asthma attacks reduced by 32%
• Emergency Room (ER) visits for respiratory symptoms reduced by 84%
• Days lost from school, work and other daily activities due to asthma symptoms, reduced by 66%
• Hospitalizations due to respiratory symptoms reduced by 79%

In another study, BT showed long-term reduction in asthma-related breathing difficulty for at-least 5 years. The benefits listed above also maintained at 5 years, when combined with inhaled corticosteroids and long-acting bronchodilators.

This proves that not only is BT effective but is the best adjuvant therapy for treating severe, persistent asthma.

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai (Alwarpet & Vadapalani), Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.

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