TEER A Non-Surgical Breakthrough for Mitral Valve Repair in Dogs

Advances in Canine Heart Disease Treatment: Transcatheter Edge-to-Edge Mitral Valve Repair (TEER) for Myxomatous Mitral Valve Disease (MMVD)

Myxomatous Mitral Valve Disease (MMVD) is the most common heart disease in dogs, especially in small to medium-sized breeds and older dogs. This disease is caused by degeneration of the mitral valve, leading to Mitral Regurgitation (MR), where blood flows backward into the left atrium. Over time, this condition can progress to Congestive Heart Failure (CHF), which significantly affects a dog's quality of life.

Traditional treatments still commonly used today, such as diuretics and pimobendan, help control symptoms and slow disease progression, but don't directly address the structural problem in the valve itself. This is where Transcatheter Edge-to-Edge Mitral Valve Repair (TEER) comes in -- a treatment technique that doesn't require major surgery, adapted from human medicine, using a device called the V-clamp to repair the mitral valve without the need for a heart-lung bypass machine. This technique has shown potential to reduce mitral regurgitation and improve quality of life for dogs with MMVD.

TEER Technique: Treatment Without Major Surgery

TEER is performed through a small surgical incision in the chest (mini-thoracotomy), without the need for a heart-lung bypass machine. The V-clamp device is inserted through the cardiac apex and installed at the A2-P2 region of the mitral valve, the area where leakage most commonly occurs. This treatment requires advanced imaging, such as Transesophageal Echocardiography (TEE) and Fluoroscopy, to ensure the device is positioned precisely.

This technique has several advantages:

• Reduced Surgery Time: takes less time than open-heart surgery
• Faster Recovery: less post-surgical pain and quicker healing
• Applicable to Multiple Cases: suitable for dogs in both early stage (B1) and more advanced stages (B2 and C) of MMVD

Case Studies: Real-Life Success Stories

1. A Beagle's Journey to Better Health (Thai Journal of Veterinary Medicine)

A case report from Thailand documents a 9-year-old, 11.8-kilogram Beagle who became the first dog in Southeast Asia to be successfully treated with TEER.

• Patient: a 9-year-old male Beagle weighing 11.8 kg, diagnosed with stage B1 MMVD
• Clinical Symptoms: a grade III/VI heart murmur, but no signs of heart failure
• Treatment: the dog was treated with TEER using a V-clamp device through a small chest incision. Imaging ensured the device was precisely positioned at the A2-P2 region of the mitral valve
• Results: after treatment, echocardiography showed no remaining regurgitation, and the size of the left atrium and ventricle decreased, indicating reduced heart pressure. The dog was healthy, with blood test results within normal range
• Significance: this was the first successful TEER treatment in Thailand and Southeast Asia, demonstrating the feasibility of treating early-stage MMVD

2. Successful TEER in 4 Dogs (Animals Journal)

TEER was used to treat 4 dogs at various stages of MMVD (2 in stage B2 and 2 in stage C). These dogs showed symptoms such as coughing, difficulty breathing, and reduced exercise tolerance, which are common symptoms of severe mitral regurgitation.

• Patients: 4 dogs with MMVD, 2 in stage B2 and 2 in stage C, with symptoms including coughing, difficulty breathing, and reduced exercise tolerance
• Treatment: all dogs were treated with TEER using a V-clamp device inserted through a small chest incision and installed at the A2-P2 region of the mitral valve
• Results: all dogs showed significantly improved respiratory symptoms and overall quality of life. Echocardiography confirmed reduced mitral regurgitation, improved heart function, and decreased size of the left atrium and ventricle. After treatment, the dogs were able to stop taking diuretics
• Complications: one dog experienced temporary arrhythmia, which was effectively treated with lidocaine. No other serious complications were found
• Follow-up: after 6 months of follow-up, all dogs maintained improved heart function with no device-related issues

Why TEER Is a Significant Advancement

1. Minimally Invasive Treatment with High Safety

TEER is a treatment that doesn't require major surgery or a heart-lung bypass machine, which helps reduce surgery time, post-surgical pain, and recovery time for dogs. It also has a low complication rate, with temporary arrhythmia being the most commonly seen complication, which can be managed with standard treatment such as lidocaine. Post-surgical pain management is also handled well with local anesthesia and opioid pain medication, helping dogs recover smoothly.

2. Effectiveness in Reducing Mitral Regurgitation

Both case studies show that TEER can effectively reduce mitral regurgitation, helping relieve symptoms and improve heart function. Dogs who received this treatment showed decreased size in the left atrium and ventricle, a clear sign of reduced heart pressure.

3. Improved Quality of Life

Owners reported their dogs had more energy, improved respiratory symptoms, and greater happiness after receiving TEER treatment. For dogs who previously struggled with exercise or chronic coughing, this treatment can be life-changing.

4. Proven Effectiveness

TEER has shown impressive results in reducing mitral regurgitation, improving heart function, and relieving symptoms associated with MMVD. Dogs who received this treatment showed better exercise tolerance, fewer respiratory issues, and an overall better quality of life.

5. Long-Term Potential

While current studies have only followed patients for 6 months, preliminary results indicate that heart function and quality of life continue to improve in dogs. Further research with larger sample sizes and longer follow-up periods will help confirm TEER's long-term effectiveness.

Challenges and Limitations

While TEER has great potential, it does have some limitations:

• Learning Curve: this treatment requires specialized equipment and expertise in using TEE and Fluoroscopy, which may make it difficult to implement in general clinics right away
• Device Limitations: the V-clamp device currently comes in limited sizes, which may make it unsuitable for dogs with larger mitral valves
• Long-Term Data: while short-term results are encouraging, further research is still needed to assess long-term safety and effectiveness

Conclusion

Transcatheter Edge-to-Edge Mitral Valve Repair (TEER) represents a significant advancement in veterinary cardiology, offering a minimally invasive treatment option for MMVD. This technique not only helps relieve symptoms, but also directly addresses the structural problem in the valve -- something traditional treatments cannot do.

Success stories from Thailand and other case studies highlight TEER's potential to transform the lives of dogs suffering from MMVD. As this technique continues to develop and becomes more widely available, it may become a standard treatment option for canine heart disease, offering hope to many pets and their owners.

If your dog has been diagnosed with MMVD, you should consult with a veterinarian about the possibility of TEER treatment. As research in this area continues to expand, TEER can help our beloved companions live longer, healthier lives, filled with happiness.

For dogs with mitral regurgitation, you can bring them in for a consultation at the Heart Center, Thonglor Pet Hospital, Rama 9.

References

1. Kijtawornrat, A., et al. (2024). Successful Transcatheter Edge-to-Edge Mitral Valve Repair via Minithoracotomy in Canine Myxomatous Mitral Valve Disease: Case Report. The Thai Journal of Veterinary Medicine.
2. Petchdee, S., et al. (2024). Transcatheter Edge-to-Edge Repair of the Mitral Valve in Four Dogs: Preliminary Results Regarding Efficacy and Safety. Animals.