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3-D printed heart valves show promise for TAVR
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Heart valve models created with advanced 3-D printers could soon assist interventional cardiologists, according to a new report published in JACC: Cardiovascular Imaging.
New data from the proof-of-concept study showed that 3-D printed tissue-mimicking phantom materials can be used to develop a procedure simulation platform for in vitro transcatheter aortic valve replacement.
A team of researchers at the Georgia Institute of Technology and Piedmont Heart Institute in Atlanta are using standard medical imaging and new 3-D printing technologies to create patient-specific heart valve models that mimic the physiological qualities of the real valves. Their goal is to improve the success rate of TAVR procedures by choosing the right prosthetic and avoiding paravalvular leakage, according to a press release.
“Paravalvular leakage is an extremely important indicator in how well the patient will do long term with their new valve,” Zhen Qian, MD, chief of cardiovascular imaging research at Piedmont Heart Institute, Piedmont Healthcare, said in the release. “The idea was, now that we can make a patient-specific model with this tissue-mimicking 3-D printing technology, we can test how the prosthetic valves interact with the 3-D printed models to learn whether we can predict leakage.”
The current retrospective study looked at 18 patients who underwent TAVR. The researchers created patient-specific aortic root phantoms using the tissue-mimicking 3-D technique, then deployed self-expanding valve prostheses (CoreValve, Medtronic) in the phantoms to simulate a TAVR procedure, then quantified post-TAVR aortic root strain. The researchers then used annular bulge index to assess post-TAVR annular strain unevenness in the phantoms and to compare the predictive value of annular bulge index vs. other known predictors of paravalvular leak after TAVR.
Results showed significant differences in maximum annular bulge index between patients with no paravalvular leak, trace or mild paravalvular leak and moderate to severe paravalvular leak (P = .001).
According to the findings, annular bulge index was identified as the only significant predictor of moderate to severe paravalvular leak, compared with the other known predictors of paravalvular leak (area under the curve, 95%; P < .0001). In a subgroup of patients with paravalvular leak after TAVR, annular bulge index correctly identified the major paravalvular leak location in nine of 12 patients (accuracy, 75%).
“A novel indicator of the post-TAVR annular strain unevenness, the annular bulge index outperformed the other established variables and achieved a high level of accuracy in predicting post-TAVR paravalvular leak, in terms of its occurrence, severity and location,” the researchers wrote.
Qian and colleagues wrote that 3-D printing “has been proposed as a fast and cost-effective way to accurately reproduce patient-specific anatomies for education, training and preprocedural planning.” Further, “multimaterial printing using colorful soft and rigid materials creates realistic visual and tactile experiences, and some day they might be used for 3-D printing-based functional evaluations.”
“These 3-D printed valves have the potential to make a huge impact on patient care going forward,” Chuck Zhang, MD, professor of the Stewart School of Industrial and Systems Engineering at Georgia Tech, said in the release.
On the basis of this proof-of-concept study, the researchers concluded that “it may be feasible to perform procedural simulations on 3-D printed phantom[s] for pre-TAVR planning, especially in those who are at high-risk for post-TAVR paravalvular leak.”
Mohamad Al khouli, MD, and Partho P. Sengupta, MD, from West Virginia University Heart and Vascular Institute, Morgantown, West Virginia, discuss the implications of this process in a related editorial.
“The advances in the TAVR field brought forth an unprecedented orchestration of collaborations in clinical medicine, advanced imaging and bioengineering,” they wrote. “The finding of this study, albeit ‘proof of concept,’ are symbolic of the next wave of innovation in transcatheter valve therapies, toward seeing a personalized patient-centered TAVR.”
Continued evaluation of this 3-D printing process will continue, according to the researchers. – by Dave Quaile
Disclosures: Qian and Zhang report no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures. Alkhouli and Sengupta report no relevant financial disclosures.
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