Angiography-versus wire-based microvascular resistance index to detect coronary microvascular obstruction associated with ST-segment elevation myocardial infarction.

Microvascular obstruction (MVO) measured by cardiac magnetic resonance (CMR) after ST-segment elevation myocardial infarction (STEMI) has important prognostic implications. While invasive index of microvascular resistance (IMR) have been shown to predict the occurrence and extent of MVO, the role of the angiography-based microvascular resistance (Angio-IMR) for this purpose remains unknown. The present study aims to perform a head-to-head comparison of wire-based and angiography-derived microcirculatory resistance (IMR and Angio-IMR, respectively) for the detection of MVO. Patients with a first STEMI and multivessel disease underwent CMR for detection of MVO, and angio-IMR and IMR measurements during PPCI and at 30 day follow up, both in STEMI culprit and non-culprit vessels. 58 patients were included (mean age 60.7 ± 9.9 years, 82% male). At the time of PPCI, angio-IMR and IMR exhibited significant correlation (r = 0.70, P < 0.001), and agreement (coefficient of agreement 0.58). Both indices showed good predictive value of MVO [Angio IMR: AUC 0.79 (95% CI: 0.667-0.928); IMR: AUC 0.70 (95% CI: 0.539-0.853); p = 0.15]. Angio-IMR 40 U and IMR 34 U were identified as best cut-offs for prediction of MVO. In non-culprit vessels, angio-IMR and IMR also correlated well (rho = 0.59, p < 0.001), with overall lower mean values compared to culprit vessels (Angio-IMR: 36 vs. 23; IMR: 39 vs. 22, p < 0.001 for both comparisons). Angio-IMR constitutes a valid alternative to wire-based IMR in predicting MVO in STEMI. Angio-IMR and IMR show a good correlation in the acute and subacute STEMI phases, both in culprit and non-culprit vessels.

Wang L ，Travieso A ，van der Hoeven N ，Lombardi M ，van Leeuwen MAH ，Janssens G ，Shabbir A ，Mejía-Rentería H ，Milasinovic D ，Gonzalo N ，Nijveldt R ，van Royen N ，Escaned J ... -  《-》

Functional angiography-derived index of microcirculatory resistance validated with microvascular obstruction in cardiac magnetic resonance after STEMI.

The index of microcirculatory resistance (IMR) measured after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) is associated with microvascular obstruction (MVO) and adverse clinical events. To evaluate MVO after successful primary PCI for STEMI without pressure wires or hyperemic agents, we investigated the feasibility and usefulness of functional angiography-derived IMR (angio-IMR). The current study included a total of 285 STEMI patients who underwent primary PCI and cardiac magnetic resonance (CMR). Angio-IMR of the culprit vessel after successful primary PCI was calculated using commercial software. MVO, infarct size, and myocardial salvage index were assessed using CMR, which was obtained a median of 3.0 days [interquartile range, 3.0-5.0] after primary PCI. Among the total population, 154 patients (54.0%) showed elevated angio-IMR (> 40 U) in the culprit vessel. MVO was significantly more prevalent in patients with angio-IMR> 40 U than in those with angio-IMR ≤ 40 U (88.3% vs 32.1%, P <.001). Infarct size, extent of MVO, and area at risk were significantly larger in patients with angio-IMR> 40 U than in those with angio-IMR ≤ 40 U (P <.001 for all). Angio-IMR showed a significantly higher discriminatory ability for the presence of MVO than thrombolysis in myocardial infarction flow grade or myocardial blush grade (area under the curve: 0.821, 0.504, and 0.496, respectively, P <.001). Angio-IMR was significantly associated with CMR-derived infarct size, extent of MVO, and area at risk. An elevated angio-IMR (> 40 U) after primary PCI for STEMI was highly predictive of the presence of MVO in CMR. This trial was registered at ClnicalTrialsgov (Identifier: NCT04828681).

Shin D ，Kim J ，Choi KH ，Dai N ，Li Y ，Lee SH ，Joh HS ，Kim HK ，Kim SM ，Ha SJ ，Jang MJ ，Park TK ，Yang JH ，Song YB ，Hahn JY ，Choi SH ，Choe YH ，Gwon HC ，Lee JM ... -  《-》

Coronary angiography-derived index of microcirculatory resistance and evolution of infarct pathology after ST-segment-elevation myocardial infarction.

This study sought to evaluate the association of coronary angiography-derived index of microcirculatory resistance (angio-IMR) measured after primary percutaneous coronary intervention (PPCI) with the evolution of infarct pathology during 3-month follow-up after ST-segment-elevation myocardial infarction (STEMI). Patients with STEMI undergoing PPCI were prospectively enrolled between October 2019 and August 2021. Angio-IMR was calculated using computational flow and pressure simulation immediately after PPCI. Cardiac magnetic resonance (CMR) imaging was performed at a median of 3.6 days and 3 months. A total of 286 STEMI patients (mean age 57.8 years, 84.3% men) with both angio-IMR and CMR at baseline were included. High angio-IMR (>40 U) occurred in 84 patients (29.4%) patients. Patients with angio-IMR >40 U had a higher prevalence and extent of MVO. An angio-IMR >40 U was a multivariable predictor of infarct size with a three-fold higher risk of final infarct size >25% (adjusted OR 3.00, 95% CI 1.23-7.32, P = 0.016). Post-procedure angio-IMR >40 U significantly predicted presence (adjusted OR 5.52, 95% CI 1.65-18.51, P = 0.006) and extent (beta coefficient 0.27, 95% CI 0.01-0.53, P = 0.041) of myocardial iron at follow-up. Compared with patients with angio-IMR ≤40 U, those with angio-IMR >40 U had less regression of infarct size and less resolution of myocardial iron at follow-up. Angio-IMR immediately post-PPCI showed a significant association with the extent and evolution of infarct pathology. An angio-IMR >40 U indicated extensive microvascular damage with less regression of infarct size and more persistent iron at follow-up.

Wang X ，Guo Q ，Guo R ，Guo Y ，Yan Y ，Gong W ，Zheng W ，Wang H ，Ai H ，Que B ，Xu L ，Huo Y ，Fearon WF ，Nie S ... -  《-》

Angiography-derived index of microcirculatory resistance as a novel, pressure-wire-free tool to assess coronary microcirculation in ST elevation myocardial infarction.

De Maria GL ，Scarsini R ，Shanmuganathan M ，Kotronias RA ，Terentes-Printzios D ，Borlotti A ，Langrish JP ，Lucking AJ ，Choudhury RP ，Kharbanda R ，Ferreira VM ，Oxford Acute Myocardial Infarction (OXAMI) Study Investigators ，Channon KM ，Garcia-Garcia HM ，Banning AP ... -  《-》

Functional Coronary Angiography-Derived Index of Microcirculatory Resistance in Patients With ST-Segment Elevation Myocardial Infarction.

The aim of this study was to evaluate the diagnostic accuracy and prognostic implications of angiography-derived index of microcirculatory resistance (angio-IMR) in patients with ST-segment elevation myocardial infarction (STEMI). The index of microcirculatory resistance (IMR) is a reliable invasive measure of coronary microvascular dysfunction in patients with STEMI. A functional coronary angiography-derived method to estimate IMR is a wire- and hyperemic agent-free alternative to IMR. The study population consisted of 2 independent cohorts. The diagnostic cohort comprised patients with IMR from the culprit vessel immediately after successful primary percutaneous coronary intervention (n = 31). The prognostic cohort was patients with STEMI who were successfully treated with primary percutaneous coronary intervention and followed for 10 years from the index procedure (n = 309). Angio-IMR was calculated using computational flow and pressure simulation. The primary outcome was a composite of cardiac death and readmission for heart failure over 10 years of follow-up. In the diagnostic cohort, angio-IMR correlated well with IMR (R = 0.778; P < 0.001). Sensitivity, specificity, accuracy, and area under the curve of angio-IMR to predict IMR >40 U were 75.0%, 84.2%, 80.6%, and 0.899 (95% confidence interval: 0.786-0.949), respectively. In the prognostic cohort, patients with angio-IMR >40 U showed significantly higher risk for cardiac death or readmission for heart failure than did those with angio-IMR ≤40 U (46.7% vs 16.6%; adjusted hazard ratio: 2.909; 95% CI: 1.670-5.067; P < 0.001). Angio-IMR >40 U was an independent predictor of cardiac death or readmission for heart failure (hazard ratio: 2.173; 95% CI: 1.157-4.079; P = 0.016) and showed incremental prognostic value compared with a model with clinical risk factors only (C index = 0.726 vs 0.666 [P < 0.001], net reclassification index = 0.704 [P < 0.001]). Angio-IMR showed high correlation and diagnostic accuracy to predict IMR. Patients with STEMI with angio-IMR >40 U showed a significantly higher risk for cardiac death or readmission for heart failure than those with preserved angio-IMR values. (Prognostic Implication of Angiography-Derived IMR in STEMI Patients; NCT04628377).

Choi KH ，Dai N ，Li Y ，Kim J ，Shin D ，Lee SH ，Joh HS ，Kim HK ，Jeon KH ，Ha SJ ，Kim SM ，Jang MJ ，Park TK ，Yang JH ，Song YB ，Hahn JY ，Doh JH ，Shin ES ，Choi SH ，Gwon HC ，Lee JM ... -  《-》