Percutaneous Establishment of Tricuspid Regurgitation: An Experimental Model for

Transcatheter Tricuspid Valve Replacement

Yuan Bai, Gang-jun Zong, Yong-wen Qin

Department of cardiology

Changhai Hospital, shanghai

Backgroud

• primary isolated tricuspid regurgitation (TR) → very rare

• Functional tricuspid regurgitation (FTR) → more frequent

• left heart valve disease

• rheumatic origin

• pulmonary hypertension

• congenital heart disease

Backgroud

Up to 48% of the patients with chronic severe mitral regurgitation have tricuspid regurgitation. -------Dreyfus GD

The number of patients with functional tricuspid regurgitation is very large.

TR is associated with a poor prognosis regardless of age, biventricular systolic function and right ventricular size.

Ann Thorac Surg. 2005;79:127–132.

TRALL

BackgroudCoexisting TR have poor functional status that increases their operative risk .

Concomitant correction of TR with LHVS yielded in-hospital mortality of 8.9% and a 10-year survival of 78±3%. ------ Kuwaki

TR does not simply “go away” after mitral valve surgery.

On long-term follow-up, the prevalence of residual TR may increase to as high as 31%. ------ McCarthy PM

J Thorac Cardiovasc Surg. 2004;127: 674 – 685.

Eur J Cardiothorac Surg. 2001;20:577–582.

Percutaneous TV technology may be initially useful for patients with FTR who are at high risk for open-heart surgery.

Backgroud

Initial data from animal studies have shown encouraging results

For detailed evaluation of the effects of percutaneous tricuspid valve replacement for regurgitation

animal models are needed !

Methods• The whole procedure was performed under

TTE and fluoroscopy guidance.

• Right atriography to identify the position of the tricuspid valve (TV)

Tricuspid annulusRAO 27°

• A 7F sheath was introduced to the tricuspid annulus. • Then a special-designed grasping forceps was advanced

through the sheath to the tricuspid valve apparatus• The forceps was used to grasp chordae tendineae or the

tricuspid valve leaflets.

forceps in sheath

A B

forceps and it’s tip

• After confirmation of TR by TTE, the grasping forceps were retracted forcibly to disrupt the chordae tendineae, producing tricuspid regurgitation, while maintaining the sheath in position.

A B

Sheep ID Severity of TRRight atrial pressure (mmHg)

Baseline 15 minutes after

1 Moderate 6 11

2 Severe 5 13

3 Severe 5 11

4 Moderate 7 12

5 Severe 6 10

6 Moderate 6 9

7 Severe 6 11

ResultsCreation of tricuspid regurgitation was successfully accomplished in 7 sheep.

Results• 2 sheep was euthanized for autopsy.• Necropsy confirmed that damage was done to the

tricuspid valve apparatus in all animals (complete transection of the anterior tricuspid leaflet)

• The remaining 5 sheep was used for transcatheter tricuspd valve replacement.

tricuspid valved stent

the implantation procedure

After the valved stent implantation, no significant TR was detected by TTE.

Discussion

• With the availability of more sophisticated percutaneous equipment, and techniques, percutaneous aortic and pulmonic valve replacement have become a promising alternative to conventional surgery.

• TAVR and TPVR have sparked interest in the development of devices and techniques for percutaneous atrioventricular valve replacement.

• There is a need for experimental models to allow improvement of the technique as well follow-up.

• Current experimental models with tricuspid valve have been created with surgical transection of papillary muscles or chordae tendineae or placement of a spiral in atrioventricular canal.

Circulation 1986; 73: 799-808.

Am J Physiol 1991; 260: H638-H641.

• An ideal animal model used for research should be similar, simple, and reproducible and associated with as little trauma as possible.

• Compared with the surgical approach for creation of TR, the percutaneous method is less traumatic and simpler.

• As the forceps grasps the chordae tendineae and is pulled back to the sheath, the risk of injury of the atrial and ventricle wall is lower.

• By means of the 7F sheath, the forceps can grasp the chordae tendineae easily.

• TR confirmed by right ventricular angiogram or TTE?

Limitations

• First, the study size is small, and therefore complications that occur at a low rate could have been missed.

• Second, this was an acute study and therefore the use of this model for evaluation of chronic TR was not investigated.

Conclusion

• A simple and reproducible percutaneous method to reliably and safely induce significant tricuspid regurgitation in sheep was developed. The procedure allows the evaluation of percutaneous tricuspid valve in intact animals and avoids the need for thoracotomy.