Balloon pulmonary angioplasty (BPA) is an emerging

minimally invasive Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition ...

procedure to treat

chronic thromboembolic pulmonary hypertension Chronic thromboembolic pulmonary hypertension (CTEPH) is a long-term disease caused by a blockage in the blood vessels that deliver blood from the heart to the lungs ( the pulmonary arterial tree). These blockages cause increased resistance to flo ...

(CTEPH) in people who are not suitable for

pulmonary thromboendarterectomy In thoracic surgery, a pulmonary thromboendarterectomy (PTE), also referred to as pulmonary endarterectomy (PEA), is an operation that removes organized clotted blood (thrombus) from the pulmonary arteries, which supply blood to the lungs. Indica ...

(PTE) or still have residual pulmonary hypertension and areas of narrowing in the pulmonary arterial tree following previous PTE. The procedure uses balloons to open

pulmonary arteries A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and t ...

that have been narrowed or blocked by webs, bands and fibrous tissue and therefore restores blood flow to the

lungs The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of th ...

, reduces

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing disc ...

, and improves

exercise tolerance Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe post ...

. More data on its safety and effectiveness are still required.

Medical uses

BPA may be considered in people with symptomatic CTEPH who are not suitable for surgery. PTE is an established treatment for CTEPH but is only performed at a few specialist centres, requires surgical competence and intermittent total circulatory arrest under deep hypothermia. However, co-existing illnesses and inaccessible clots may contraindicate performing the operation. Up to 40% of those diagnosed with CTEPH are considered ineligible for surgery. Selection criteria may vary between centres.

Technique

BPA is performed by specialists in a

catheterization laboratory A catheterization laboratory, commonly referred to as a cath lab, is an examination room in a hospital or clinic with diagnostic imaging equipment used to visualize the arteries of the heart and the chambers of the heart and treat any stenosis o ...

. Each procedure takes between two and four hours and most people undergo up to six treatments with the first two sessions being performed a fortnight apart and subsequent treatments being individually tailored upon follow-up assessment. A

local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general an ...

and moderate

sedation Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...

are used but a

general anaesthetic General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced coma ...

is not required, hence the person remains awake throughout the procedure. After inserting the catheter into the

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

of the

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

( right internal jugular vein) or

groin In human anatomy, the groin (the adjective is ''inguinal'', as in inguinal canal) is the junctional area (also known as the inguinal region) between the abdomen and the thigh on either side of the pubic bone. This is also known as the medial comp ...

( right femoral vein), a hollow tube is introduced through the catheter and passed to the affected blocked lung arteries.

X-rays An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...

and pressures in the narrowed arteries are assessed by the specialist team before a thin wire with a deflated balloon is guided through the blood vessels to the site of blockage, where the balloon is then inflated. This mainly disrupts the organised thrombus and to a lesser degree presses it against the walls of the arteries. This increases the size of the lumen of the arteries, thus opening them and allowing the blood flow to be restored. The balloon is then deflated and removed. A number of arteries can be treated during each BPA procedure.

Recovery and follow-up

One overnight stay in hospital is usually required. This is followed by a check up appointment within three months. The overall survival has been shown to be comparable with PTE and better than with medication only.

Complications

The pulmonary arteries have thinner walls than the blood vessels of the heart and therefore injury by rupture or

dissection Dissection (from Latin ' "to cut to pieces"; also called anatomization) is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause o ...

caused by over-dilatation of the balloon or piercing pulmonary arteries by the tip of the guide wire, resulting in

haemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagi ...

, are risks. Injury to the lung including reperfusion oedema is also a possibility and these injuries are less likely with more experienced specialists.

History

BPA was originally developed and established for treating children with congenital

pulmonary stenosis Pulmonic stenosis, is a dynamic or fixed obstruction of flow from the right ventricle of the heart to the pulmonary artery. It is usually first diagnosed in childhood. Signs and symptoms Cause Pulmonic stenosis is usually due to isolated valvula ...

. Subsequently, it was first tried for the treatment of CTEPH in 1988. Initial results of performing BPA in inoperable CTEPH were reported in 2001, but had a high mortality. Since 2012, reports of the effect of BPA has mainly come from the National Hospital Organization Okayama Medical Center in Japan where the procedure was refined and where smaller balloons were used. In addition, the number of balloon inflations per session were carefully limited to one or two lung vessel segments with targeting only one lung lobe during each session. Intravascular imaging was also introduced.

Research

More data on its safety and effectiveness are still required. Long-term results on disease recurrence, the requirement for

stent In medicine, a stent is a metal or plastic tube inserted into the lumen of an anatomic vessel or duct to keep the passageway open, and stenting is the placement of a stent. A wide variety of stents are used for different purposes, from expandab ...

ing and long-term survival also need to be evaluated. In addition, studies to clarify BPA's comparability with the drug

riociguat Riociguat, sold under the brand name Adempas, is a medication by Bayer that is a stimulator of soluble guanylate cyclase (sGC). It is used to treat two forms of pulmonary hypertension (PH): chronic thromboembolic pulmonary hypertension (CTEPH) ...

are needed.

References

{{Reflist, 30em Pulmonary heart disease and diseases of pulmonary circulation Vascular procedures