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Experimental aortic regurgitation in rats under echocardiographic guidance.

BACKGROUND AND AIM OF THE STUDY
Experimental aortic regurgitation (AR) induced by retrograde perforation of the aortic leaflets has been used as an animal model of volume overload, but causes high mortality. In the past, AR was induced under hemodynamic guidance, but echocardiography can be used to guide the investigator as well as grade AR severity and monitor left ventricular function. The study aim was to assess the value of echocardiography in experimental AR in rats.


METHODS
Sixty-six Wistar rats (bodyweight 250-275 g) underwent perforation of the aortic leaflets via a right transcarotid approach to induce moderate to severe AR. Transthoracic echocardiographic guidance was used to assess catheter location, degree of AR, ventricular function and complications.


RESULTS
Echocardiographic images were easily obtained and of excellent quality (M-mode, two-dimensional and complete Doppler evaluation). Catheter location, movement and guidance during aortic valve perforation were straightforward, and AR gradation and ventricular function easily assessed. Procedural complications and causes of death were identified. Had hemodynamic criteria been used, 24% of AR cases would have been misgraded. With echocardiography, the overall mortality rate was 17% (<10% in the last 25 animals).


CONCLUSION
Echocardiographic guidance is mandatory for protocols of experimental AR. Using this technique, the procedure is simplified, and is more accurate, more reproducible and safer for the animals.