Research Article

Mechanical and Pharmacological Revascularization Strategies for Prevention of Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction: Analysis from Index of Microcirculatory Resistance Registry Data

Table 2

Coronary angiography findings and physiological assessment of study population.

ParameterTotal (N = 160)High IMR (N = 54)Low IMR (N = 106) value

Angiographic parameters
 Multivessel, n (%)61 (38.1%)29 (53.7%)32 (30.2%)0.006

 Vascular territory, n (%)
  LAD114 (71.2%)41 (75.9%)73 (68.9%)0.454
  LCX14 (8.8%)6 (11.1%)8 (7.5%)0.647
  RCA32 (20.0%)7 (13.0%)25 (23.6%)0.168

 Initial TIMI grade, n (%)
  TIMI 0–1100 (62.5%)39 (72.2%)61 (57.5%)0.101
  TIMI 243 (26.9%)13 (24.1%)30 (28.3%)0.703
  TIMI 317 (10.6%)2 (3.7%)15 (14.2%)0.079

 Final TIMI grade, n (%)
  TIMI 216 (10.0%)12 (22.2%)4 (3.8%)0.001
  TIMI 3144 (90.0%)42 (77.8%)102 (96.2%)0.001

 Final TMPG, n (%)
  TMPG 245 (28.1%)27 (50.0%)18 (17.0%)<0.001
  TMPG 3112 (70.0%)25 (46.3%)87 (82.1%)<0.001

 TIMI thrombus grade, n (%)0.215
  Grade 14 (2.5%)2 (3.7%)2 (1.9%)
  Grade 212 (7.5%)3 (5.6%)9 (8.5%)
  Grade 325 (15.6%)4 (7.4%)21 (19.8%)
  Grade 436 (22.5%)13 (24.1%)23 (21.7%)
  Grade 583 (51.9%)32 (59.3%)51 (48.1%)

 Collateral flow grade, n (%)0.215
  Rentrop 1115 (71.9%)41 (75.9%)74 (69.8%)
  Rentrop 235 (21.9%)12 (22.2%)23 (21.7%)
  Rentrop 31 (0.6%)0 (0.0%)1 (0.9%)
 Distal embolization, n (%)26 (16.2%)17 (31.5%)9 (8.5%)<0.001
 No reflow, n (%)15 (9.4%)8 (14.8%)7 (6.6%)0.162

Physiologic parameters
 Pa (hyp), mm Hg86.0 ± 16.384.9 ± 17.486.5 ± 15.70.564
 Pd (hyp), mm Hg78.5 ± 15.178.7 ± 15.778.5 ± 14.90.915
 Tmn at rest, sec0.5 [0.3–0.8]0.7 [0.6–1.0]0.4 [0.3–0.6]<0.001
 Tmn, hyperemia, sec0.3 [0.2–0.4]0.6 [0.4–0.8]0.2 [0.2–0.3]<0.001
 FFR0.9 [0.9–1.0]0.9 [0.9–1.0]0.9 [0.9–1.0]0.256
 CFR1.6 [1.1–2.4]1.3 [1.0–1.8]1.8 [1.2–2.6]<0.001
 IMR, U22.1 [13.7–34.9]39.8 [34.9–52.2]16.5 [12.5–22.1]<0.001
 IMRcorr, U22.4 [13.9–35.0]40.2 [34.9–52.2]16.4 [12.4–22.2]<0.001

CFR, coronary flow reserve; FFR, fractional flow reserve; Tmn, mean transit time; IMR, index of microcirculatory resistance; IMRcorr, corrected IMR; LAD, left anterior descending artery; LCX, left circumflex artery; MVD, microvascular dysfunction; Pa (hyp), mean aortic pressure during hyperemia; Pd (hyp), mean distal coronary pressure during hyperemia; RCA, right coronary artery; Tmn, mean transit time; TIMI, thrombolysis in myocardial infarction; TMPG, thrombolysis in myocardial infarction myocardial perfusion grade.