Table 4: Comparison of myocardial perfusion parameters at rest and stress among TIMI flow grades.

Myocardial perfusion parametersTIMI flow grades
Grade 0Grade 1Grade 2Grade 3W * 𝑃

A (db):
rest1.06 ± 0.02*§†3.17 ± 0.084.49 ± 0.32*5.29 ± 0.47382.13.000
stress1.01 ± 0.06*§†3.09 ± 0.114.83 ± 0.09*5.71 ± 0.53*499.64.000

β (s−1):
rest0.13 ± 0.02*§†0.17 ± 0.030.24 ± 0.03*0.28 ± 0.01192.61.000
stress0.11 ± 0.06*§†0.23 ± 0.05*§#0.57 ± 0.04*#0.71 ± 0.09*318.15.000

A ×  β (db/S):
rest0.14 ± 0.01*§†0.54 ± 0.031.08 ± 0.02*1.39 ± 0.04450.96.000
stress0.11 ± 0.01*§†0.71 ± 0.01*§#2.75 ± 0.09*#4.05 ± 0.11*601.17.000
A-reserve0.95 ± 0.08*§†0.98 ± 0.071.08 ± 0.07*1.09 ± 0.05452.14.000
β-reserve0.85 ± 0.02*§†1.36 ± 0.022.37 ± 0.03*2.54 ± 0.05267.82.000
A ×  β-reserve0.79 ± 0.02*§†1.31 ± 0.032.55 ± 0.06*3.11 ± 0.05539.74.000

A: indicates myocardial blood volume; β: myocardial blood flow velocity; A ×  β: myocardial blood flow; A-reserve: stress A/rest A; β-reserve: stress β/rest β; A ×  β-reserve: stress A ×  β/rest A ×  β;  TIMI: thrombolysis in myocardial infarction trial.
The correlation between the means of A, β, and A ×  β at rest and TIMI grade reached significant (rs  =  0.741, 0.528, and 0.715, resp., 𝑃 values <.001).
The correlation between the means of A, β, and A ×  β at stress and TIMI grade reached significant (rs  =  0.872, 0.767, and 0.845 for A, β, and A ×  β, resp., 𝑃 values <.001).
* 𝑃 < . 0 0 1 versus TIMI grade 3.
§ 𝑃 < . 0 0 1 versus TIMI grade 2.
𝑃 < . 0 0 1 versus TIMI grade 1.
# 𝑃 < . 0 0 1 versus parameter in rest.
*Welch tests.