Elevated Native T1 Values is in Myocardium Regions are Supplied by Stenotic Coronary Arteries

Background: T1 mapping is a novel tool allowing robust quantification of myocardial damage.

Purpose: To quantify and compare the native T1 values in myocardial segments supplied by infarct related (IRA) or stenotic and non-stenotic non IRA`s.

Methods. Consecutive patients with first STEMI (N=61, mean age 59 y, male 90%) underwent primary PCI for IRA and a cardiac MRI scan within 3±2 days. Obstructive coronary disease was defined as ≥50% stenosis. MRI studies (3T) included steady state free precession, late gadolinium enhancement and MOLLI T1 mapping. T1 mapping values were presented by 16^th segment AHA model including a total of 976 segments. T1 values were compared between the IRA, stenotic and non-stenotic non IRA`s.

Results.

IRA was documented as the LAD, RCA and LCX in 36, 17 and 8 cases, respectively. Mean native T1 values for LAD IRA (stented), LAD non IRA (≥50% stenosis) (not stented), LAD non IRA (≥50% stenosis) (stented) and LAD non IRA (<50% stenosis) were 1455±72; 1321±44; 1322±22 and 1283±32, respectively, P for trend and RCA non IRA (<50% stenosis) were 1438±92; 1334±43; 1374±101 and 1311±34, respectively, P for trend

Conclusion.

As expected, the highest native T1 values were documented in the stented IRA`s. However, native T1 values were also elevated in non IRA`s (both stented and non-stented) with obstructive coronary disease (≥50% stenosis) in comparison with non-obstructive disease (<50% stenosis). Thus, the evidence of remote myocardial damage challenges the issue of complete revascularization in STEMI patients.

Figure. T1 map in case of 2 vessel coronary artery disease with RCA-IRA and LAD >70% stenosis that not stented. In IRA segments the range of T1 values 1405-1600, in stenotic LAD 1289-1473, in normal LCX 1232-1354, respectively, was found.