Initial experience with a steerable intravascular ultrasound catheter in the aorta and pulmonary artery.

The aim of this protocol was to test the feasibility and safety of a prototype steerable intravascular ultrasound (IVUS) catheter (Boston Scientific, Waterton, MA) in comparison with standard IVUS catheters. A 3.5F, 20-MHz mechanical echo transducer was incorporated into a bendable sheath with a blunt tip. The flexible IVUS catheter was compared with a standard IVUS catheter in 13 patients. Seven patients underwent catheterization of the left side of the heart, and six patients had catheterization of the right side of the heart for suspected recurrent pulmonary embolism. In the aorta, three lumen area measurements were made: (1) midway between the aortic arch and the aortic root, (2) at the most cranial part of the aorta, and (3) in the descending aorta at the level of the diaphragm. Evaluation of the accuracy of luminal dimension measurements by both types of catheters in perpendicular positions to the vessel wall was evaluated in a hollow rubber cast of an human aorta and its side branches, representing luminal diameters from 3 to 26 mm. We performed 20 measurements with each type of catheter. The results were compared with ruler measurements, after the cast had been cut in slices. The equation for the standard 3.5F IVUS catheter was: y = 0.89x + 0.15; SE = 0.17; r = .97; for the 4.8F 20-MHz standard IVUS catheter: y = 0.97x + 0.05; SE = 0.18; r = .98; and for the steerable catheter, y = 0.94x + 0.09; SE = 0.12; r = 0.97.(ABSTRACT TRUNCATED AT 250 WORDS)