Tricuspid Annuloplasty - Indications, Procedure, Complications, and Outcomes

Introduction

Tricuspid valve disease impacts millions of people worldwide. The disease of the tricuspid valve generally arises in the form of regurgitation. The American college of cardiology and the American heart association of 2014 practice guidelines advise valve repair surgery for managing individuals with valvular heart disease, particularly left-sided valve surgery, is the advised treatment for tricuspid regurgitation. The main tricuspid valve repair technique is annuloplasty in the presence of a dilated annulus, along with normal leaflets and chordal structures in the case of tricuspid regurgitation. The key objective of annuloplasty is reducing the annular diameter size of the tricuspid valve.

What Is Tricuspid Regurgitation?

Tricuspid valve is between the heart's upper and lower chambers. It prevents blood from circulating back into the right upper chamber during ejection (systole). Tricuspid valve regurgitation occurs when the valve does not shut completely. This can change the heart's structure and permanently damage the heart. Tricuspid valve annulus dilation and restriction in movement of flaps due to right ventricle remodeling are the important mechanisms contributing to secondary tricuspid regurgitation.

What Is Tricuspid Annuloplasty?

Tricuspid annuloplasty is a surgical procedure to modify the annulus diameter of the tricuspid valve and restore its normal dimensions and function with a specially designed ring that can be rigid or flexible or various suture repair methods depending on the technique of the repair. This ring placement reduces the dilated annulus size, which is generally true in tricuspid regurgitation.

What Are Different Annuloplasty Techniques?

Various suture annuloplasty techniques, such as the kay and de vega techniques.

• Ring annuloplasty with a flexible or rigid band.

• Teflon strip band annuloplasty.

• The clover technique.

• Transcatheter annuloplasty.

What Are the Indications of Tricuspid Annuloplasty?

Tricuspid otoplasty may be needed in case of regurgitation associated with the following conditions;

• Endocarditis.

• Myxomatous degeneration of the tricuspid valve.

• Carcinoid syndrome.

• Rheumatic heart disease.

• Drugs and toxins such as Fenfluramine and Phentermine.

• Chest irradiation.

• Chest trauma.

• Pacemaker lead-induced tricuspid regurgitation.

• Ischemic or nonischemic cardiomyopathies.

• Cardiac defibrillator-induced tricuspid regurgitation.

• Aortic or mitral valvular disease.

• Right ventricle cardiomyopathy.

• Right ventricle volume overload.

• Atrial fibrillation.

• Pulmonary diseases include pulmonary emboli and chronic obstructive pulmonary disease.

What Are the Benefits of Tricuspid Annuloplasty?

Correction of significant tricuspid regurgitation is done by tricuspid annuloplasty, which provides certain benefits, as mentioned below;

• Improve right ventricular (lower heart chambers) shape, function, and pulmonary artery (blood vessel of the lung) pressures.

• Improvement in the functional capacity of the heart and survival rate.

• Prevents the advancement of tricuspid regurgitation and dilatation of the right ventricular valves.

• Avoids the need for future tricuspid valve repair surgery, which usually carries a high operative risk.

How Is the Tricuspid Annuloplasty Performed?

Several studies suggest a lower recurrence rate and improved survival rate of tricuspid regurgitation when an annuloplasty ring is used when compared to suture annuloplasty. Various techniques for tricuspid annuloplasty are described below;

The Ring Annuloplasty:

• The operator measures the size of the tricuspid annulus by various muscle-pulling techniques and measuring the size between specific landmarks.

• After measuring the diameter, a smaller ring is selected, carefully fixed, and tied at the annulus using sutures. Again, great care is taken not to distort the geometry of the tricuspid valve.

• After proper placement of the ring is assured, the operator runs a water test while occluding the pulmonary artery to confirm the competency of the repaired valve.

Kay Annuloplasty:

• The posterior flap of the tricuspid valves is completely excluded by suturing them together. This obtains a functional bicuspid valve.

• It is preferable to put reinforcing suture over the first stitch.

The De Vega Annuloplasty:

It is the most popular technique for the repair of tricuspid annulus dilatation.

• Sutures are directed around the edge of the orifice of the dilated annulus in a counterclockwise direction.

• The other parallel suture is positioned about one to two mm outside the last suture and finally tied together.

Clover Technique:

This technique was presented by Alfieri et al. in 2003 to correct severe functional tricuspid insufficiency. The clover technique consists of stitching together the central point of the free rims of the tricuspid flaps by using a suture and adding a semi-rigid ring. Due to this, the tricuspid valve becomes clover-shaped. This technique is effective even in complex cases of primary or secondary tricuspid regurgitation and post-traumatic tricuspid regurgitation.

What Are the Complications of Tricuspid Annuloplasty?

Complications directly related to tricuspid valve annuloplasty are not common. Still, they do occur and include the following;

• Injury to the right coronary artery (blood vessel supplying oxygenated blood to the heart muscles) from too deep placement of the sutures in the region of the posterior annulus.

• Injury to the aorta wall (a large blood vessel carrying blood from the heart to the entire body) from too deep sutures in the area of the anterior annulus.

• Annular and ring split or gap due to friable tissue is more common following rigid ring annuloplasty (8.7 %) than flexible band annuloplasty (0.9 %).

• The risk of requiring a permanent pacemaker following annular and ring split or gap.

• Injury to the right coronary artery. The dilated tricuspid annulus has more risk of this complication due to distortion of the path of the right coronary artery. Also, calcified coronary arteries may increase risk due to their kink susceptibility.

• Right coronary artery occlusion or narrowing can happen due to an annuloplasty suture passing through or around it. In such cases, removing the annuloplasty ring and sutures or coronary artery bypass graft surgery is necessary.

What Are the Outcomes of Tricuspid Annuloplasty?

The placement of a ring provides more durable repair, especially in the case of the presence of pulmonary hypertension or severe tricuspid annular dilation. In addition, compared to suture annuloplasty, ring annuloplasty also provides better event-free and long-term survival up to 15 years post-surgery.

The treatment failure rate for tricuspid regurgitation by a suture or a ring annuloplasty one month after surgery varies from 8 to 15 %.

Risk factors for failure include the followings;

• The severity of preoperative tricuspid regurgitation.

• Pulmonary hypertension.

• Presence of pacemakers.

• Left ventricular dysfunction.

• Severe tethering of the flaps of the tricuspid valve.

• Increased left ventricular remodeling.

Conclusion

Severe tricuspid regurgitation prevalence is not negligible and is associated with poor prognosis. In addition, surgical options have a large drawback due to a high risk of mortality and morbidity in cases of tricuspid regurgitation. Placement of an annuloplasty ring or band during tricuspid valve repair is associated with reduced tricuspid regurgitation recurrence and improved long-term and event-free survival.