Baseline characteristics of the patients
A total of 223 patients in our cardiac center were enrolled, which including 112 patients with AF and 111patients without AF who served as control. The mean age of the AF patients in the trial was 70.28 years old and 65.22 years old in the control group. 66.61% of patients in AF group and 57.14% in the control group were male patients. Clinical comorbidities, including hypertension, diabetes, and history of stroke/TIA, and New York Heart Association classification grading of cardiac function as well as eGFR between the 2 groups were shown in Table 1. Baseline procedural characteristics were all comparable shown in Table 2. including PCI-related vessel and periprocedural treatment.
We found higher QFR ratio in AF patients as compared to patients in the control group (0.792 ± 0.011 vs. 0.685 ± 0.016, p＜0.001) which determined in the whole diseased coronary artery (Figure 3.). In consistent with the result of the whole diseased coronary artery, local QFR around the stenoses (0.858 ± 0.0287 vs. 0.756 ± 0.014, p=0.002), residual QFR (0.958 ± 0.005 vs. 0.929 ± 0.009, p=0.005), index QFR (0.807 ± 0.010vs. 0.713 ± 0.014, p<0.0001) were all higher in AF patients as compared to the control. These findings support the hypothesis that deduced from the FFR measurement [7-8].
QFR results of the corresponding coronary artery
We found a statistically significant difference in QFR results between patients had AF and did not have AF at the average level of all coronary arteries. Then we sought to distinguish whether these difference were donated by certain coronary arteries, We then compared the QFR values of Left anterior descending coronary artery (LAD), Left circumflex coronary artery (LCX), Right coronary artery(RCA) and other diseased vessels in the two groups. Results showed higher QFR ratio in LAD (0.781 ± 0.016 vs. 0.656 ± 0.020, p＜0.001) and RCA as well as other vessels (0.801 ± 0.020 vs. 0.699 ± 0.053, p=0.045). QFR values of LCX showed comparable results (0.814 ± 0.024 vs. 0.751 ± 0.026, p=0.112) between AF patients and non-AF patients in the control group.
Flow resistance of the related coronary artery and blood flow velocity
After determined the QFR results, we sought to evaluate the relationship between extent and vascular resistance(mmHg*S/m) of the related coronary artery and blood flow velocity(M/s) on QFR results in AF patients. Then we found a lower trend of vascular resistance of the related coronary artery in AF patients as compared to the non-AF patients, however the result did not show significance （165.9 ± 11.51 vs. 199.9 ± 13.94，p=0.061）. It's worth noting that we revealed that AF patients with lower blood flow velocity as compared to the control group of non-AF patients (0.130 ± 0.006 vs. 0.153 ± 0.005, p=0.003). The above result implies that lower blood flow velocity might associated with an increased prevalence of QFR results in AF vessels.
Anatomy of the lesion
After determined the relationship between flow velocity and QFR results in AF patients, we next sought to evaluate whether the anatomy of the lesion could affect the results above. First, we found a comparable length of lesion(mm) in two groups of patients (18.83 ± 0.93 vs. 20.11 ± 0.92, p=0.328). However, results showed that the area rate (%) of stenosis at the lesion were significantly lower in AF patients (71.67 ± 1.291vs.77.6 ± 1.184, p=0.001). Consistent with the rate of lumen stenosis, AF patients showed higher minimum lumen area (MLA, mm2) as compared to the control (1.65 ± 0.097 vs. 1.11 ± 0.062, p＜0.001). We further analyzed the mean distorted angle of the coronary(17.47°± 0.55°vs. 18.63°± 0.63°, p=0.167) and mean distorted angle of the lesion around the stenosis(17.36°± 0.74°vs.18.71°± 0.71°, p=0.189), both showed no significance. However, It's worth noting that AF patients showed a decreased maximum lesion distorted angle compared to the control(28.14°± 1.16°vs. 31.95°± 1.23°, p=0.025).