3-D printing shows promise for predicting location of paravalvular leak

SAN DIEGO — Preliminary results of a small study demonstrate the effectiveness of preprocedure 3-D printing and computer modeling to predict the location of paravalvular leak in patients undergoing transcatheter aortic valve replacement.

As use of and interest in 3-D printing continues to grow in the medical community, these new data suggest that it may play a role in identifying paravalvular leak, which remains a challenge for TAVR operators.

“If we can identify it before TAVR, we can prevent it,” Sergey Gurevich, MD, cardiovascular fellow at the University of Minnesota, told Cardiology Today’s Intervention. The data were reported at the Society for Cardiovascular Angiography and Interventions Scientific Sessions.

The current study focused on six patients undergoing TAVR for severe calcific aortic stenosis at risk for paravalvular leak. Five patients received a 26-mm valve and one received a 23-mm valve. Gurevich said these are the preliminary results looking at the first six of 20 patients.

The researchers analyzed pre-TAVR CT scans of the native aortic valve and segmented them for printing of 3-D models using virtual rendering software. Then, the 3-D aortic root models were implanted with Sapien XT (Edwards Lifesciences) frames at nominal pressure to determine whether the size was correct, ultimately revealing where calcium composites would be. The next step was scanning of the ex vivo implanted 3-D models for final analysis of the paravalvular leak location. These scans were then compared with in vivo implanted TAVR echocardiograms, Gurevich explained.

In the six patients, every leak seen on the 3-D models was confirmed on the CT scans. The researchers also observed that most patients had significant calcification in areas of poor stent apposition, when compared with the pre-TAVR CT scans. Two patients had central aortic insufficiency, which was possibly related to prosthesis mismatch, according to the findings.

The 3-D models allowed researchers to use prototypes to personalize valve placement, size and location to stop leaks and lower calcium buildup.

“The idea behind this project is to see whether knowing the structural aspect of the aortic root before TAVR can [aid us] in predicting the patients who may have [paravalvular leak]. If we can predict it, there’s a high likelihood that we can fix that, either by using a different type of valve or a different size, for example,” Gurevich told Cardiology Today’s Intervention. In this case, “3-D printing, as far as using it for preprocedure planning, is successful in identifying paravalvular leak.”

The researchers’ future research will focus on a functional study to determine the exact size of paravalvular leak. Their current work involves computational fluid dynamics to optimize calculations, “which basically creates parameters of pressure on either side of the valve and you can predict how much leak and where the leak is going,” Gurevich said. – by Katie Kalvaitis

Reference:

Gurevich S, et al. 3D Printing and Computer Modeling to Predict Paravalvular Leak in Transcatheter Aortic Valve Replacement. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; April 25-28, 2018; San Diego.

Disclosure: Gurevich reports no relevant financial disclosures.