Advancements in Canine Cardiac Care Transcatheter Edge-to-Edge Mitral Valve Repair (TEER) for MMVD

Myxomatous Mitral Valve Disease (MMVD) is the most common cardiac condition in dogs, predominantly affecting small-to-medium and senior breeds. The disease stems from the degeneration of the mitral valve, leading to Mitral Regurgitation (MR), where blood leaks backward into the left atrium. Left untreated, this progression eventually leads to Congestive Heart Failure (CHF), severely diminishing a dog's quality of life.

While conventional treatments—such as diuretics and Pimobendan—effectively manage symptoms and slow disease progression, they do not address the underlying structural defect of the valve. This is where the Transcatheter Edge-to-Edge Mitral Valve Repair (TEER) technique offers a breakthrough. Adapted from human medicine, TEER is a minimally invasive procedure that utilizes a V-clamp device to repair the mitral valve without the need for open-chest surgery or a heart-lung bypass machine. This innovative technique has shown immense potential in reducing regurgitation and significantly improving the long-term quality of life for dogs suffering from MMVD.

The TEER Technique A Breakthrough in Minimally Invasive Heart Care

TEER is a minimally invasive procedure performed through a small incision in the chest (mini-thoracotomy), eliminating the need for a heart-lung bypass machine. The V-clamp device is guided through the cardiac apex and securely positioned at the A2-P2 segment of the mitral valve—the area most frequently associated with severe leakage. To ensure pinpoint accuracy, the procedure relies on advanced imaging technologies, including Transesophageal Echocardiography (TEE) and Fluoroscopy.

This technique offers several significant advantages :

• Reduced Procedure Time Requires considerably less time than traditional open-heart surgery.
• Faster Recovery Minimal postoperative pain allows pets to return to their normal lives much sooner.
• Broad Applicability Highly effective for dogs across various stages of MMVD, including Stage B1, B2, and C.

Case Study: A Real-Life Success Story

1. A Health Journey of a Beagle (Published in the Thai Journal of Veterinary Medicine)

This case marks a historic milestone in Thailand, featuring a 9-year-old Beagle, weighing 11.8 kg, who became the first dog in Southeast Asia to successfully undergo the TEER procedure.

• Patient Profile: A 9-year-old male Beagle, 11.8 kg, diagnosed with MMVD Stage B1.
• Clinical Presentation: A Grade III/VI heart murmur was detected, though the patient showed no clinical signs of congestive heart failure.
• Treatment: The patient underwent the TEER procedure using the V-clamp device through a mini-thoracotomy. Advanced imaging guided the precise placement of the device at the A2-P2 segment of the mitral valve.
• Outcomes: Post-operative echocardiography revealed zero residual regurgitation. Furthermore, the dimensions of both the left atrium and left ventricle decreased, indicating a reduction in cardiac pressure. The patient remained healthy with all blood parameters within normal ranges.
• Significance: This success represents the first triumphant TEER treatment in Thailand and Southeast Asia, proving the viability of treating MMVD in its early stages.

2. TEER Success in Four Clinical Cases (Published in Animals Journal)

The TEER procedure was performed on four dogs at advanced stages of MMVD (two in Stage B2 and two in Stage C). These patients exhibited severe symptoms such as chronic coughing, difficulty breathing, and exercise intolerance—classic signs of significant mitral regurgitation.

• Patient Profile: Four dogs diagnosed with MMVD Stages B2 and C, all presenting with respiratory distress and reduced physical activity.
• Treatment: Each dog underwent the TEER procedure using the V-clamp device. The device was guided through a mini-thoracotomy and securely attached to the A2-P2 segment of the mitral valve.
• Outcomes: All patients showed remarkable improvement in respiratory symptoms and overall quality of life. Post-operative echocardiography confirmed a significant reduction in mitral regurgitation, improved cardiac function, and a decrease in the size of the left atrium and ventricle. Notably, the dogs were able to discontinue diuretic medications following the procedure.
• Complications: One patient experienced transient arrhythmia, which was successfully managed with Lidocaine. No other major complications were reported.
• Follow-up: At the 6-month follow-up, all four dogs maintained improved cardiac function with no device-related issues.

Why TEER Represents a Major Leap Forward in Veterinary Cardiology

• Minimally Invasive with Superior Safety TEER eliminates the need for open-chest surgery and heart-lung bypass, significantly reducing procedure time, post-operative pain, and recovery duration. It boasts a low complication rate; transient arrhythmias are the most common side effect and are easily managed with standard protocols like Lidocaine. Pain management is highly effective using local anesthetics and opioids, ensuring a smooth recovery.
• Effective Regurgitation Reduction Clinical studies consistently show that TEER effectively reduces mitral regurgitation, alleviating symptoms and improving cardiac function. A notable decrease in left atrial and ventricular dimensions serves as a clear indicator of reduced cardiac pressure.
• Enhanced Quality of Life Pet owners report significant improvements in their dogs' energy levels, respiratory health, and overall happiness. For dogs previously struggling with exercise intolerance or chronic coughing, TEER is truly life-changing.
• Proven Clinical Efficacy TEER has demonstrated impressive results in managing MMVD-related symptoms. Patients show improved exercise stamina and fewer respiratory issues, leading to a much healthier daily life.
• Long-Term Potential While current studies focus on a 6-month follow-up, early data suggests sustained improvements in heart function and well-being. Ongoing research with larger groups will further solidify TEER as a long-term gold standard for mitral valve repair.

Challenges and Limitations of TEER

While TEER shows immense potential, it is important to acknowledge certain clinical limitations

• Learning Curve and Expertise This procedure requires highly specialized equipment and advanced proficiency in Transesophageal Echocardiography (TEE) and Fluoroscopy. Consequently, its availability may be limited to specialized cardiac centers rather than general veterinary clinics.
• Equipment Constraints Currently, the V-clamp device is available in limited sizes. This may restrict its use in larger dogs or those with exceptionally large heart valves.
• Need for Long-Term Data Although short-term outcomes are highly favorable, continued research is essential to fully evaluate the long-term safety and durability of the device over several years.

Conclusion

Transcatheter Edge-to-Edge Mitral Valve Repair (TEER) represents a pivotal milestone in veterinary cardiology, offering a minimally invasive breakthrough for treating MMVD. Unlike traditional medical management, this technique goes beyond merely controlling symptoms—it directly addresses the structural heart valve defect.

The success stories from Thailand and other international case studies highlight the life-changing potential of TEER. As this technology evolves, it is poised to become the gold standard for canine heart care, offering renewed hope to countless pets and their owners.

If your dog has been diagnosed with MMVD, we encourage you to consult with a specialist about the possibilities of TEER. As research in this field continues to grow, TEER will play a vital role in ensuring our beloved companions live longer, healthier, and happier lives.

For pets suffering from mitral regurgitation, you can receive expert consultation and advanced care 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.