Recently, our team performed surgery to remove heartworms from a local dog.

 

When is heartworm removal by surgery indicated?

• When heartworms have migrated downstream into the right atrium and right ventricle, causing obstruction, surgery to remove the worms is recommended.

• If heartworms are present in the pulmonary artery, their removal is technically challenging and may cause more harm than good. In such cases, the standard protocol recommended by the American Heartworm Society should be followed.

 

The 12-year-old dog presented with fainting on exertion (syncope), which was attributable to severe pulmonary hypertension (increased lung pressure). Pulmonary hypertension is a common condition secondary to heartworm disease.

Our challenges remained:

• Risk of shock and blood clot formation. 

• Severe pulmonary hypertension may impair hemodynamic stability and oxygenation during anaesthesia.

 

Mitigation:

• Drugs to reduce clotting were administered. 

• Our anesthetic team also performed invasive blood pressure measurement and capnography. A catheter was inserted into an artery to accurately measure arterial blood pressure, while the dog’s exhaled air was connected to a device to measure and display the concentration of carbon dioxide (CO₂). Arterial blood pressure monitoring is not a routine procedure for general anesthesia as it is technically difficult and requires a special monitor.

 

Using echocardiography and fluoroscopy, we removed five heartworms from the dog. The dog recovered from anesthesia uneventfully.