Methods for the production of temporary valvular lesions

Abstract

Experimental valvular lesions have been induced by a number of investigators—stenoses by tightening of ligatures or clamps about the valvular orifices, insufficiencies by tearing of valves with sounds and glass rods or by cutting with specially constructed valvulotomes. Such experimental stenoses may, if desired, be temporary, and normal circulatory conditions may be subsequently reëstablished. Experimental insufficiencies such as have been described, must, owing to the traumatic nature of the lesion, be permanent. As no method for the production of temporary insufficiencies has apparently been described, the following method, which also permits a study of the intraventricular pressure changes, was devised.

Method.—A curved metal catheter (22 cm. long, internal diameter 6 mm.) having toward the tip one or two openings (6 mm. in diameter) and three centimeters from the tip a longitudinal slot (6 mm. wide and 25 mm. long) is fitted with a lubricated rubber tube (4 mm. internal diameter) so as to occlude the longitudinal slot. To produce aortic insufficiency, the metal catheter with its rubber obturator is introduced, free from air and without hemorrhage, into the left subclavian artery and aorta. The catheter is so adjusted by palpation that the valves close about it near the middle of the occluded slot in the catheter. The inner rubber tube may now be connected directly with a manorneter. 1 Aortic pressure records with Frank's manometer show that a catheter of such size that it can be introduced into the subclavian does not impede the systolic discharge so as to cause stenosis in the physiological sense. By drawing out the obturating rubber tube to such an extent that the slot is opened, a valveless circuit with a minimal resistance is established between aorta and ventricle. The intraventricular pressure may still be recorded.