High index of microcirculatory resistance level after successful primary percutaneous coronary intervention can be improved by intracoronary administration of nicorandil.
BACKGROUND
Although microvascular dysfunction following percutaneous coronary intervention (PCI) can be evaluated with the index of microcirculatory resistance (IMR), no method of treatment has been established. We hypothesized that intracoronary administration of nicorandil can improve IMR after successful primary PCI in patients with ST-segment elevation myocardial infarction (STEMI).


RESULTS
In 40 patients with first STEMI after successful primary PCI, IMR was measured using PressureWire(TM) Certus (St. Jude Medical, MN, USA). In 20 of the patients (Group N), IMR was measured at baseline and after intracoronary nicorandil (2 mg/10 ml). In the other 20 patients (Control), IMR was measured at baseline, after intracoronary saline (10 ml) and after intracoronary nicorandil (2 mg/10 ml). In Group N, IMR significantly decreased after intracoronary nicorandil (median IMR, 27.7-18.7 U, P<0.0001). In the Control group, IMR did not change after saline administration (median IMR, 24.3-23.8 U, P=0.8193), but was significantly decreased after intracoronary nicorandil (median IMR, 23.8-14.9 U, P<0.0001). Next, all 40 patients were divided into subgroups by tertile of baseline IMR. In those with intermediate to high IMR (baseline IMR > or =21), intracoronary nicorandil significantly decreased IMR, although it did not change IMR in those with low IMR (baseline IMR <21).


CONCLUSIONS
High IMR levels in patients with STEMI after successful primary PCI can be improved by intracoronary administration of nicorandil.
Critical & Cardiovascular Care Unit, Osaka Saiseikai Senri Hospital, Suita, Japan. norinoriito@hotmail.co.jp
Noritoshi
N
Ito
Shinsuke
S
Nanto
Yasuji
Y
Doi
Hirotaka
H
Sawano
Daisaku
D
Masuda
Shizuya
S
Yamashita
Ken-ichiro
K
Okada
Shoji
S
Kaibe
Yasuyuki
Y
Hayashi
Tatsuro
T
Kai
Toru
T
Hayashi
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage*; D017115:Catheter Ablation; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology* / Q000628:therapy*; D020108:Nicorandil / Q000008:administration & dosage*; D011446:Prospective Studies; D014655:Vascular Resistance / Q000187:drug effects*
D000889:Anti-Arrhythmia Agents; D020108:Nicorandil