Comprehensive assessment of microcirculation after primary percutaneous intervention in ST-segment elevation myocardial infarction: insight from thermodilution-derived index of microcirculatory resistance and coronary flow reserve.
OBJECTIVE
A pathophysiological mechanism of microvascular dysfunction in ST-segment elevation myocardial infarction (STEMI) is multifactorial; thus, multiple modalities were needed to precisely evaluate a microcirculation.


METHODS
We complementarily assessed microcirculation in STEMI by the index of microcirculatory resistance (IMR) and coronary flow reserve (CFR) immediately after a primary percutaneous intervention in 89 STEMI patients. Cardiovascular and cerebrovascular events (MACCE) including cardiovascular death, target vessel failure, heart failure, and stroke were assessed during a mean follow-up period of 3.0 years.


RESULTS
The microcirculation of enrolled patients was classified into four groups using cutoff CFR and IMR values (CFR>2 and mean IMR): group-1 (n=23, CFR>2 and IMR ≤ 27); group-2 (n=31, CFR ≤ 2 and IMR ≤ 27); group-3 (n=9, CFR>2 and IMR>27); and group-4 (n=26, CFR<2 and IMR>27). On echocardiography 3 months later, improvement in the wall motion score index was shown in group-1 (P<0.01), group-2 (P<0.01), and group-3 (P=0.04), whereas group-4 did not show improvement in wall motion score index (P=0.06). During clinical follow-up, there were no MACCE in group-1 and the patients in group-2 and group-3 showed significantly lower MACCE compared with group-4 (group-1=0%, group-2, and group-3=10%, group-4=23.1%, P=0.04).


CONCLUSIONS
Complimentary assessment of microcirculation by the IMR and CFR may be useful to evaluate myocardial viability and the long-term prognosis of STEMI patients.
Department of Internal Medicine, Division of Cardiology, Inha University Hospital, Incheon, South Korea.
Sang-Don
SD
Park
Yong-Soo
YS
Baek
Man-Jong
MJ
Lee
Sung Woo
SW
Kwon
Sung-Hee
SH
Shin
Seong-Ill
SI
Woo
Dae-Hyeok
DH
Kim
Jun
J
Kwan
Keum-Soo
KS
Park
D003331:Coronary Vessels / Q000503:physiopathology*; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D062645:Percutaneous Coronary Intervention; D011184:Postoperative Period; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D013815:Thermodilution / Q000379:methods; D014655:Vascular Resistance / Q000502:physiology*