Recently, Dr. Chandan Deepak Bhavnani from Pusat Jantung Sarawak and president of National Heart Association of Malaysia Dr. Alan Yean Yip Dr Fong's team published results of a clinical trial using coronary angiography-derived fractional flow reserve measurement system caFFR. The paper was published in Journal of Asian Pacific Society of Cardiology (JAPSC). This was the first study of its kind in Southeast Asia. Based on previous trials, this trial advances the clinical significance of caFFR value for intermediate coronary artery stenosis. The results showed that caFFR had a good agreement with wire-based FFR. The 12-month outcomes showed that caFFR-guided deferral of PCI was safe and comparable to wired-based FFR guidance.

The caFFR system is a novel wire-free technique developed by RainMed. The Flash FFR trial from 2019 showed high accuracy (96%), sensitivity (90%) and specificity (98%) compared to traditional wired-based FFR using the same cut-off value of 0.80 for significance. The coronary angiography FFR (caFFR) system uses computational fluid dynamics (CFD) to solve the Stokes Navier equation and real time aortic pressure to determine the flow rate. 2D analysis of the angiogram is done to reconstruct a 3D image of the coronary artery to determine the FFR across a stenotic segment of the coronary artery. Originally, the computational fluid dynamics method was time-consuming and required more than 30 minutes of processing. The caFFR system uses a specially designed CFD method to determine wire-free FFR with a processing time of 1 minute and an operational time of less than 5 minutes.

It was a prospective, single-centre study. In total, 69 patients (93 vessels) with angiographic stenosis of 30–90% and a vessel size of ≥2 mm in the stenotic segment by visual estimate were included. Wire-based FFR was done as a comparison at the operator’s discretion, using the Abbott pressure wire X with the wire tip at least 3 cm distal to the lesion of interest. The primary endpoint was a composite of all-cause mortality, MI and target vessel revascularisation at 12 months in patients who had caFFR-guided PCI deferral.

Research Result: A Bland Altman plot (Figure 1) was done to analyse the performance of caFFR and wire-based FFR. There was good agreement between the means and differences of caFFR and wire-based FFR. There was no proportional bias as evidenced by a negative linear t-test with a p-value of 0.257.

On follow-up at 12 months, none of the patients had died, but 28 (89.7%) remained in chronic coronary syndrome class 1. A Kaplan–Meier curve constructed for the primary outcome showed that only one patient met the primary outcome, representing 3.4% of the study population (Figure 2). This patient had a target vessel revascularisation for persistent symptoms of angina.

The 12-month outcome showed that caFFR-guided PCI deferral is safe and comparable to previously published trials on wire-based FFR. In the patients that had wire-based FFR done for comparison, caFFR showed good agreement with wire-based FFR. Our event rate of 3.4% at 12 months is similar to the PCI deferral group in contemporary wire-based trials such as the DEFINE FLAIR and iFR SWEDEHEART trial.

this is the first study to assess caFFR-guided PCI deferral in Southeast Asia and has the potential to aid further risk stratification of patients with intermediate coronary artery stenosis. caFFR system is one of the core products of RainMed’s FlashBot vascular interventional surgery robot. In the future, it will be integrated into FlashBot together with caIMR system, which will be commercialized in the near future, to enable the robot to "observe" and "think".

In the future, RainMed Medical will continue to uphold the purpose of "Targeted medical services for people's health", innovatively launch vascular interventional surgery robot to gradually form an "unmanned operating room". Clinicians will be free from tedious, time-consuming work, and the majority of patients will be offered innovative treatment solutions.