Table 4. Predictors of variability.

Univariate predictors of absolute difference >0.03 between 1st and 2nd QFR analysis		Multivariate analysis
	p-value	OR	p-value
FFR/0.10	0.002	0.73 (0.55-0.98)	0.036
Observer (1 as reference)
2	0.037	2.75 (1.13-6.71)	0.026
3	0.014	3.39 (1.38-8.33)	0.008
4	<0.001	9.08 (3.55-23.21)	0.000
5	<0.001	5.98 (2.41-14.8)	0.000
Contrast flow velocity (0.05-0.15 m/s as reference)
0.16-0.25 m/s	0.049	1.35 (0.72-2.56)	0.352
>0.25 m/s	0.245	0.85 (0.30-2.41)	0.760
Angiographic quality score/1 unit	0.003	0.72 (0.53-0.99)	0.041
FFR: fractional flow reserve; OR: odds ratio; QFR: quantitative flow ratio