pulmonary artery | Horse Racing Free Tips

Human Cardiac Procedure Saves Foal’s Life

A ten-day-old foal born in Switzerland became the first equine to undergo a successful balloon valvuloplasty to correct a malfunctioning valve. The Dales pony was born with a congenital heart defect that caused the leaflets of the pulmonary artery to stick together and block blood flow to the lungs, reports The Horse.

Veterinarians were able to pass a balloon through the jugular vein and inflate it across her pulmonary valve. This procedure is used in human medicine and with dogs, says Dr. Katharyn Mitchell, who treated the filly.

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The foal was weak and feverish when she was referred to the University of Zurich Equine Hospital. Veterinarians determined she had a strong heart murmur and further testing showed that she had pulmonary stenosis in addition to an infection.

As the filly had no other heart defects and because of her size, the veterinarians opted to try the valvuloplasty. Because the surgery is based on human medicine, there is an upper-end size limit for an animal that can be treated; the foal was at the upper threshold of this limit. The filly was placed under general anesthesia for the procedure, which involved both small animal cardiologists and large animal internal medicine specialists.

Though somewhat lethargic in the first year of her life, the now 2-year-old is showing normal behavior and stamina. The veterinarians advised her owners to refrain from breeding her, though there is no evidence that the heart defect is hereditary.

Study: Heaves Can Wreak Havoc On More Than Just Lungs

Horses with uncontrolled respiratory disease have more organs at risk than simply their lungs, new Canadian research shows. Drs. Serena Ceriotti, Michela Bullone, Mathilde Leclere, Francesco Ferrucci and Jean-Pierre Lavoie have discovered that horses with uncontrolled respiratory disease are at risk of having pulmonary arterial changes that could lead to heart failure.

Horses that suffer from severe equine asthma have inflamed airways; they also cough and have difficulty breathing. The researchers hypothesized that this condition, which is triggered by dust and mold in a horse's hay and environment, can put horses at risk of pulmonary hypertension. Pulmonary hypertension occurs when the walls of the pulmonary arteries thicken and increase the horse's blood pressure.

For the study, the research team obtained multiple post-mortem lung samples from 18 horses: six that were in heaves episodes when they died; six that were in remission from heaves from being kept in a dust-free environment; and six that had no heaves and served as controls.

The researchers measured the thickness of the arteries and found that horses with uncontrolled asthma had thicker arterial walls than other horses in the study.

Why the artery walls thicken when a horse has breathing trouble is unknown, but it is hypothesized that the low oxygen content and inflammation may increase the amount of smooth muscle in the artery walls, which makes it more difficult for blood to move out of the lungs. Eventually, this condition could lead to an enlargement and failure of the right ventricle of the heart.

The final part of the team's study focused on potential treatments for pulmonary hypertension in horses: they used 11 asthmatic horses divided into two groups that were treated for a full year with two different treatment protocols. One group had reduced dust exposure, primarily through the feeding of hay alternatives. The second group went on a corticosteroid for the first six months, the had dust control measures added in. Both treatments led to a reversal in arterial wall thickness, but changes in the second group were not seen until the dust control measures were taken.

They scientists determined that the thickening of arterial walls in horses with heaves can be reversed, but environmental changes must be made; the administration of corticosteroids, while helpful, must be made in conjunction with changes in management.

Read the full study here.

Equine Asthma Causes Thickening of Arterial Walls In Lungs

Researchers have found that horses with severe asthma also have arterial walls that are thickened in the lung. This condition can also be found in humans that have chronic obstructive pulmonary disease; it contributes to pulmonary hypertension.

Severe asthma in horses is chronic lower airway disease; airway obstruction recurs when the horse is exposed to environmental triggers like hay mites and fungi. Drs. Serena Ceriotti, Michela Bullone, Mathilde Leclere, Francesco Ferrucci and Jean-Pierre Lavoie wanted to see if there were changes to the pulmonary arteries in asthmatic horses and how widely distributed these changes were. They also sought to see if the condition was reversible, either by inhaling corticosteroids or by avoiding allergens.

The study found that both actively asthmatic horses and those in remission had increased wall areas and that the pulmonary artery smooth muscle mass was increased. Both inhaled corticosteroids and allergen avoidance reversed the wall increase, but the smooth muscle only returned to normal during avoidance.

They concluded that equine asthma caused thickening of smooth muscle mass in pulmonary arteries. They also determined that the narrowing of the arteries could contribute to pulmonary hypertension. Avoiding triggers was found to be more effective than inhaled corticosteroids to control the disease.

Read the full study here.