Abstract 12632: Impact of Systolic Pressure Response on Measurement of Fractional Flow Reserve

Abstract

Background: Fractional flow reserve (FFR) is calculated as the ratio between distal coronary pressure(Pd)and aortic pressure(Pa)during whole cardiac cycle at stable hyperemia. In clinical practice, we experience various Pd wave pattern during hyperemia, such as decreasing equally in systolic and diastolic phase, or mainly decreasing in diastolic phase. Purpose: The aim of the study was to evaluate the impact of systolic and diastolic pressure response during hyperemia in patients with coronary stenosis and an FFR of less than 0.8. Methods: A total of 35 patients (40 stenosis)had FFR of less than 0.8 were enrolled. FFR measurements were performed using a standard technique. Based on Pa and Pd wave forms, the decreasing area in systolic and diastolic were calculated by integrating Pa-Pd pressure gradient during hyperemia using the RadiView2.2 software. %Sys value was defined as the percentage of delta systolic area during the whole cardiac cycle (Figure). The results of %Sys values were divided into tertiles to evaluate the most significant factors for systolic pressure response. Results: Vessel distribution was as follows: LAD (60%), CX (20%) and RCA (20%). There was a significant difference of vessel distribution in coronary arteries in the upper tertile compared with the other two tertiles of %Sys values (p=0.028). However, the other factors such as FFR value, lesion length and severity, history of diabetes mellitus and previous myocardial infraction were not affected by the %Sys values. In addition, there was a significant difference of %Sys values among three major coronary arteries (LAD 49.4±18.5%, CX 81.5±38.7%, RCA 67.5±20.2%, p=0.006). %Sys values were significantly higher in non-LAD lesions compared with LAD lesions (74.5±30.7% vs 49.4±18.5%, p=0.003). Conclusions: There was a significant difference of decreasing pattern of Pd wave during hyperemia among the three coronary arteries. These findings suggest that iFR might not be accurate in non-LAD lesion.