It has become increasingly apparent that revascularization of ischemia-associated lesions is the superior treatment in the patients with CAD. However, if a coronary stenosis is not associated with inducible ischemia, medical treatment is indicated better than PCI. Therefore, it is important to determine whether such an association exists when selecting therapy for CAD. Since the introduction of coronary angiography, various methods have been introduced to assess the severity and clinical significance of the stenosis in coronary arteries. Measurements of FFR, rather than visual estimations of coronary obstruction have demonstrated the greatest accuracy for determining the functional significance of coronary artery stenosis. Additionally, the FAME trial revealed that outcomes achieved following PCI performed based on FFR measurements were better than those achieved following PCI performed based on angiographic results alone.
However, the pressure wire used in taking coronary FFR measurements is very flimsy and difficult to maneuver. Thus, in practice, it has been difficult to insert the pressure guidewire and manipulate it to determine the functional significance of complex coronary artery lesions, such as bifurcation lesions, diffuse lesions, and calcified tortuous lesions. Such difficulties result in increased fluoroscopy time and dye usage. In such cases, the interventional physicians must repeatedly remodel the shape of the pressure guidewire, and make repeated attempts to push it through the target lesion. This process can damage the pressure sensors in the wire, and affect the accuracy of FFR measurements.
Presently, there are numerous different types of workhorse guidewires available; many of which are preferred by different interventional cardiologists. Due to their good tensile strength, and increased maneuver ability, lubrication, and tactile feedback, these guidewires can easily engage complex coronary lesions. Additionally, their low traumatic effects and high ease of use have made them excellent wires for engaging complex lesions during postprovisional stenting. In our new technique, a workhorse guidewire was used to initially engage a complex lesion, and then insert a broken balloon carried by a pressure guidewire through the lesion along the workhorse guidewire. Next, the broken balloon and workhorse guidewire were withdrawn following separation of the balloon from the pressure guidewire. The profile of the balloon used in an actual operation should be as small as possible, (e.g., 1.5–2.0 mm), to reduce its effects on the lesion or the structure of the stent. Although the new FFR measurement technique required puncturing the balloon, this did not appear to increase the operation risk or the probability of failure (P > 0.05).
Our new method reduced the technical difficulty of using pressure wire, and also decreases the fluoroscopy time, and volume of contrast medium required for a FFR procedure. FFR measurements are crucial for evaluating the physiologic significance of complex coronary artery lesions, which can help determine whether certain coronary interventions are feasible and thus prevent unnecessary complex interventions and their related complications. Our NOV technique will facilitate making timely and economically sound decisions related to treatment of complex lesions such as bifurcation, diffuse and calcified tortuous lesions. However, both our new technique and study results also have limitations that should be mentioned.
Due to the difficulties encountered when evaluating the physiologic significance of complex coronary artery lesions, we proposed a NOV technique for obtaining measurements of FFR. Compared with the CON technique used to measure FFR, the new technique has advantages of reduced fluoroscopy time and contrast dye usage, without increasing the risk of operation or decreasing the success rate.
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Edited by: Yi Cui
Source of Support: Nil.
Conflict of Interest: None declared.