Percutaneous Establishment of Tricuspid Regurgitation: An Experimental Model for Transcatheter...
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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
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.