Multicenter clinical evaluation of a piezoresistive-MEMS-sensor rapid-exchange pressure microcatheter system for fractional flow reserve measurement

Objectives: This multicenter, prospective clinical study investigates whether the microelectromechanical-systems-(MEMS)-sensor pressure microcatheter (MEMS-PMC) is comparable to a conventional pressure wire in fractional flow reserve (FFR) measurement.

Background: As a conventional tool for FFR measurement, pressure wires (PWs) still have some limitations such as suboptimal handling characteristics and unable to maintain the wire position during pullback assessment. Recently, a MEMS-PMC compatible with any 0.014″ guidewire is developed. Compared with the existing optical-sensor PMC, this MEMS-PMC has smaller profiles at both the lesion crossing and sensor packaging areas.

Methods: Two hundred and forty-two patients with visually 30-70% coronary stenosis were enrolled at four centers. FFR was measured first with the MEMS-PMC, and then with the PW. The primary endpoint was the Bland-Altman mean bias between the MEMS-PMC and PW FFR.

Results: From the 224-patient per-protocol data, quantitative coronary angiography showed 17.9% and 55.9% vessels had diameter < 2.5 mm and stenosis >50%, respectively. The two systems' mean bias was -0.01 with [-0.08, 0.06] 95% limits-of-agreement. Using PW FFR≤0.80 as cutoff, the MEMS-PMC per-vessel diagnostic accuracy was 93.4% [95% confidence interval: 89.4-96.3%]. The MEMS-PMC's success rate was similar to that of PW (97.5 vs. 96.3%, p = .43) with no serious adverse event, and its clinically-significant (>0.03) drift rate was 43% less (9.5 vs. 16.7%, p = .014).

Conclusions: Our study showed the MEMS-PMC is safe to use and has a minimal bias equal to the resolution of current FFR systems. Given the MEMS-PMC's high measurement accuracy and rapid-exchange nature, it may become an attractive new tool facilitating routine coronary physiology assessment.