PARIS – Intravascular ultrasound can reliably be used in lieu of multidetector computerized tomography for the key task of annular sizing in patients undergoing transcatheter aortic valve replacement, Dr. Diaa Hakim declared at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.
Multidetector CT (MDCT) is considered the standard imaging method for this purpose. But the requirement for contrast media makes MDCT problematic for patients with chronic kidney disease, who can easily be driven into acute kidney injury through exposure to this material.
Bruce Jancin/Frontline Medical News
Dr. Diaa Hakim
Moreover, renal failure is common among patients with a failing native aortic valve. Interventionalists who perform transaortic valve replacement (TAVR) are encountering renal failure more and more frequently as the nonsurgical treatment takes off in popularity. An alternative imaging method is sorely needed, observed Dr. Hakim of the University of Alabama at Birmingham.
Unlike MDCT, intravascular ultrasound (IVUS) doesn’t require contrast. And in Dr. Hakim’s head-to-head comparative trial conducted in 50 consecutive TAVR patients who underwent annular sizing by both methods, there were no significant differences between the two in measurements of maximum and minimum annular diameter, mean annular diameter, or annular area.
The decision as to the size of the replacement aortic valve was based upon MDCT, which was performed first. Then came IVUS carried out with a Boston Science Atlantis PV Peripheral IVUS catheter at 8-French and 15 Hz. The catheter was advanced over the guidewire, then pullback imaging was obtained automatically from the left ventricular outflow tract to the aortic root. The IVUS measurements were made at the level of basal attachment of the aortic valve cusps, which was quite close to the same point as the MDCT measurements.
Post TAVR, 37 of the 50 patients had no or trivial paravalvular regurgitation. Six patients developed acute kidney injury.
Asked if he believes IVUS now enables operators to routinely skip MDCT for TAVR patients, Dr. Hakim replied, “Not for the moment.” In patients with chronic kidney disease, yes, but in order for IVUS for annular sizing to expand beyond that population it will be necessary for device makers to develop an IVUS catheter with better visualization, a device designed specifically to see all the details of the aortic valve and annulus. He noted that the Atlantis PV Peripheral IVUS catheter employed in his study was designed for the aorta, not the aortic valve. It doesn’t provide optimal imaging of the valve cusps, nor can it measure paravalvular regurgitation after valve implantation.
How much time does IVUS for annular sizing add to the TAVR procedure? “Five minutes, no more,” according to Dr. Hakim.
He reported having no financial conflicts regarding this study, conducted free of commercial support.