Elevated native T1 values is in myocardial regions supplied by stenotic coronary arteries

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

To quantify and compare the native T1 values in myocardial segments supplied by an infarct related artery (IRA) and stenotic and non-stenotic artery (non IRA).

Consecutive patients with first STEMI underwent primary PCI for IRA and some non IRA's a followed by cardiac MRI scan within 5±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 using a 16th segment AHA model. T1 segmental values were compared between the IRA and non IRA (stenotic and non-stenotic).

The study cohort included 61 patients (mean age 59 y, male 90%). A total of 891 segments were analyzed (excluded segments (artifacts) N=85). 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, overall P<0.001. For LCX IRA (stented), LCX non-IRA (≥50% stenosis) (not stented), LCX-non IRA (≥50% stenosis) (stented) and LCX non IRA (<50% stenosis) were 1362±75; 1277±50; 1277±72 and 1289±77, respectively, overall P<0.001. For RCA IRA (stented), RCA non-IRA (≥50% stenosis) (not stented), RCA-non IRA (≥50% stenosis) (stented) and RCA non IRA (<50% stenosis) were 1438±92; 1334±43; 1374±101 and 1311±34, respectively, overall P<0.001. Native T1 values in non-IRA LAD ≥50% stenosis vs LAD <50% stenosis were 1321±40 and 1283±32, respectively P=0.02, whereas non-IRA RCA ≥50% stenosis vs RCA <50% stenosis were 1345±61 and 1312±34 respectively, P=0.05.

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, documenting the presence of myocardial damage in remote segments. This finding sheds new light on the issue of complete revascularization in STEMI patients.

Type of funding source: None