Assessment of endothelial cell function and physiological microcirculatory reserve by video microscopy using a topical acetylcholine and nitroglycerin challenge

Table 2 Properties of the microcirculation before and after the sublingual topical application of acetylcholine and nitroglycerin, as measured using manual video analysis and algorithm-based video analysis

	Native	Acetylcholine	Nitroglycerin	p
TVD (manual) [mm/mm²]	14.81 ± 0.65	15.72 ± 0.49	20.32 ± 0.50^{a, b}	<0.0001
Space-time diagram-based venular flow velocity [μm/s]	242 ± 21	358 ± 62	496 ± 22^a	<0.01
TVD (algorithm-based) [mm/mm²]	18.80 ± 0.61	18.69 ± 0.66	21.06 ± 0.57^{a, b}	<0.01
APSI [1]	1.33 ± 0.06	1.43 ± 0.08	1.64 ± 0.08^a	0.02

Values are given as mean ± SEM. Pairwise analysis is represented by ^{a, b} where p < 0.05 versus native^a, and acetylcholine^b. Analysis was performed in n = 41 subjects for TVD (manual), TVD (algorithm-based) and APSI, and in n = 23, n = 27, and n = 14 subjects in the native, acetylcholine, and nitroglycerin condition for space-time diagram-based venular flow velocity, respectively
TVD total vessel density, APSI average perfused speed index