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.