A new constrictor device for external induction of a long-term stable and irreversible renal artery stenosis in the dog

A new externally adjustable constrictor device for renal artery stenosis in the dog is described. The constrictor combines hydraulic and mechanical characteristics, and is connected to the exterior of the animal by a thin catheter. Applying hydraulic pressure via the catheter causes the plunger in the device to compress the renal artery to any desired degree of stenosis. A mechanical catch prevents backward movement of the plunger, thus ensuring a stable, irreversible renal artery constriction. This constrictor was implanted in 13 dogs, together with an electromagnetic blood flow sensor around a renal artery. In twelve dogs the constriction procedure was performed 3-12 weeks after implantation, and in all 12 cases the intended degree of stenosis [defined as percentage renal blood flow reduction (RBF)] was achieved within a range of 10%. In 5 dogs the long-term stability of the stenosis was studied and the RBF reduction appeared to be stable up to at least 6 weeks after constriction. In conclusion, the presented constrictor device is easily externally adjustable, and allows induction of a stable renal artery stenosis of various degrees in the conscious dog.