AUTHOR=Kotronias Rafail A. , Terentes-Printzios Dimitrios , Shanmuganathan Mayooran , Marin Federico , Scarsini Roberto , Bradley-Watson James , Langrish Jeremy P. , Lucking Andrew J. , Choudhury Robin , Kharbanda Rajesh K. , Garcia-Garcia Hector M. , Channon Keith M. , Banning Adrian P. , De Maria Giovanni Luigi 

TITLE=Long-Term Clinical Outcomes in Patients With an Acute ST-Segment-Elevation Myocardial Infarction Stratified by Angiography-Derived Index of Microcirculatory Resistance

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.717114

DOI=10.3389/fcvm.2021.717114

ISSN=2297-055X

ABSTRACT=<p><bold>Aims:</bold> Despite the prognostic value of coronary microvascular dysfunction (CMD) in patients with ST-segment-elevation myocardial infarction (STEMI), its assessment with pressure-wire-based methods remains limited due to cost, technical and procedural complexities. The non-hyperaemic angiography-derived index of microcirculatory resistance (NH IMR<sub>angio</sub>) has been shown to reliably predict microvascular injury in patients with STEMI. We investigated the prognostic potential of NH IMR<sub>angio</sub> as a pressure-wire and adenosine-free tool.</p><p><bold>Methods and Results:</bold> NH IMR<sub>angio</sub> was retrospectively derived on the infarct-related artery at completion of primary percutaneous coronary intervention (pPCI) in 262 prospectively recruited STEMI patients. Invasive pressure-wire-based assessment of the index of microcirculatory resistance (IMR) was performed. The combination of all-cause mortality, resuscitated cardiac arrest and new heart failure was the primary endpoint. NH IMR<sub>angio</sub> showed good diagnostic performance in identifying CMD (IMR &gt; 40U); AUC 0.78 (95%CI: 0.72–0.84, <italic>p</italic> &lt; 0.0001) with an optimal cut-off at 43U. The primary endpoint occurred in 38 (16%) patients at a median follow-up of 4.2 (2.0–6.5) years. On survival analysis, NH IMR<sub>angio</sub> &gt; 43U (log-rank test, <italic>p</italic> &lt; 0.001) was equivalent to an IMR &gt; 40U(log-rank test, <italic>p</italic> = 0.02) in predicting the primary endpoint (hazard ratio comparison <italic>p</italic> = 0.91). NH IMRangio &gt; 43U was an independent predictor of the primary endpoint (adjusted HR 2.13, 95% CI: 1.01–4.48, <italic>p</italic> = 0.047).</p><p><bold>Conclusion:</bold> NH IMR<sub>angio</sub> is prognostically equivalent to invasively measured IMR and can be a feasible alternative to IMR for risk stratification in patients presenting with STEMI.</p>