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

Abstract

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 an infarct related artery (IRA) and stenotic and non-stenotic artery (non IRA). Methods 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). Results 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. 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, documenting the presence of myocardial damage in remote segments. This finding sheds new light on the issue of complete revascularization in STEMI patients. Funding Acknowledgement Type of funding source: None