Influence of pre-infarction angina, collateral flow, and pre-procedural TIMI flow on myocardial salvage index by cardiac magnetic resonance in patients with ST-segment elevation myocardial infarction.
BACKGROUND
In patients with ST-segment elevation myocardial infarction (STEMI) pre-infarction angina, pre-procedural TIMI flow and collateral flow to the myocardium supplied by the infarct related artery are suggested to be cardioprotective. We evaluated the effect of these factors on myocardial salvage index (MSI) and infarct size adjusting for area at risk in patients with STEMI treated with primary percutaneous coronary intervention.


RESULTS
Cardiac magnetic resonance (CMR) was used to measure myocardial area at risk within 1-7 days and final infarct size 90 ± 21 days after the STEMI in 200 patients. MSI was calculated as (area-at-risk infarct size) / area-at-risk. Patients with pre-infarction angina had a median MSI of 0.80 (IQR 0.67 to 0.86) versus 0.72 (0.61 to 0.80) in those without pre-infarction angina, P = 0.004). In a regression analysis of the infarct size plotted against the area-at-risk there was a strong trend that the line for the pre-infarction angina group was below the one for the non-angina group (P = 0.05). Patients with pre-procedural TIMI flow 0/1, 2 and 3 had a median MSI of (0.69 (IQR 0.59 to 0.76), 0.78 (0.68 to 0.86) and 0.85 (0.77 to 0.91), respectively (P<0.001). Collateral flow did not change MSI (P = 0.45) nor area-at-risk (P = 0.40) and no significant difference in infarct size adjusted for area at risk (P = 0.25) was observed.


CONCLUSIONS
Pre-infarction angina increases MSI in patients with STEMI supporting the theory that pre-infarction angina leads to ischemic preconditioning. As opposed to the presence of angiographically visible collateral flow to the infarct area pre-procedural TIMI flow is strongly associated with MSI.
Department of Cardiology, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark. jacoblonborg@gmail.com
Jacob
J
Lønborg
Henning
H
Kelbæk
Niels
N
Vejlstrup
Hans Erik
HE
Bøtker
Won Yong
WY
Kim
Lene
L
Holmvang
Erik
E
Jørgensen
Steffen
S
Helqvist
Kari
K
Saunamäki
Leif
L
Thuesen
Lars Romer
LR
Krusell
Peter
P
Clemmensen
Thomas
T
Engstrøm
D000787:Angina Pectoris / Q000188:drug therapy / Q000473:pathology* / Q000628:therapy; D003097:Collateral Circulation; D017023:Coronary Angiography; D005260:Female; D006305:Health Status Indicators; D006439:Hemodynamics; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000473:pathology* / Q000628:therapy; D009206:Myocardium; D012044:Regression Analysis; D018570:Risk Assessment / Q000379:methods; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D015912:Thrombolytic Therapy; D013997:Time Factors