Temporal Trends in Takotsubo Syndrome: Results From the International Takotsubo Registry.

BACKGROUND: The perception of takotsubo syndrome (TTS) has evolved significantly over the years, primarily driven by increased recognition of acute complications and mortality. OBJECTIVES: This study aimed to explore temporal trends in demographic patterns, risk factors, clinical presentations, and outcomes in patients with TTS. METHODS: Patients diagnosed with TTS between 2004 and 2021 were enrolled from the InterTAK (International Takotsubo) registry. To assess temporal trends, patients were divided into 6 groups, each corresponding to a 3-year interval within the study period. RESULTS: Overall, 3,957 patients were included in the study. There was a significant demographic transition, with the proportion of male patients rising from 10% to 15% (P = 0.003). Although apical TTS remained the most common form, the diagnosis of midventricular TTS increased from 18% to 28% (P = 0.018). The prevalence of physical triggers increased from 39% to 58% over the years (P < 0.001). There was a significant increase in 60-day mortality over the years (P < 0.001). However, a landmark analysis excluding patients who died within the first 60 days showed no differences in 1-year mortality (P = 0.150). CONCLUSIONS: This study of temporal trends in TTS highlights a transition in patients demographic with a growing prevalence among men, increasing recognition of midventricular TTS type, and increased short-term mortality and rates of cardiogenic shock in recent years. This transition aligns with the rising prevalence of physical triggers, as expression of increased recognition of TTS in association with acute comorbidities.

Complete vs. Culprit-Only Revascularization in Older Patients with ST-segment Elevation Myocardial Infarction: An Individual Patient Meta-Analysis.

Background: Complete revascularization is the standard treatment for patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease. The Functional Assessment in Elderly MI Patients with Multivessel Disease (FIRE) trial confirmed the benefit of complete revascularization in a population of older patients, but the follow-up is limited to 1 year. Therefore, the long-term benefit ( > 1-year) of this strategy in older patients is debated. To address this, an individual patient data meta-analysis was conducted in STEMI patients aged 75 years or older enrolled in randomized clinical trials investigating complete vs. culprit-only revascularization strategies. Methods: PubMed, Embase, and the Cochrane database, were systematically searched to identify randomized clinical trials comparing complete vs. culprit-only revascularization. Individual patient-level data were collected from the relevant trials. The primary endpoint was death, myocardial infarction (MI), or ischemia-driven revascularization. The secondary endpoint was cardiovascular death or myocardial infarction. Results: Data from seven RCTs, encompassing 1733 patients (917 randomized to culprit-only and 816 to complete revascularization), were analyzed. The median age was 79 [77-83] years. Females were 595 (34%). Follow-up ranged from a minimum of six months to a maximum of 6.2 years (median 2.5 [1-3.8] years). Complete revascularization reduced the primary endpoint up to four years (HR 0.78, 95%CI 0.63-0.96), but not at the longest available follow-up (HR 0.83, 95%CI 0.69-1.01). Complete revascularization significantly reduced the occurrence of cardiovascular death or MI at the longest available follow-up (HR 0.76, 95%CI 0.58-0.99). This was observed even when censoring the follow-up at each year. Long-term rate of death did not differ between complete and culprit-only revascularization arms. Conclusions: In this individual patient data meta-analysis of older STEMI patients with multivessel disease, complete revascularization reduced the primary endpoint of death, MI or ischemia-driven revascularization up to 4-year. At the longest follow-up, complete revascularization reduced the composite of cardiovascular death or MI, but not the primary endpoint. Clinical Study Registration: PROSPERO CRD42022367898.

Development and validation of a novel angiography-derived index of absolute coronary blood flow and resistance.

Intracoronary continuous thermodilution has been recently proposed as an invasive method to quantify absolute coronary flow (Qabs) and resistance (Rabs) in vivo. The aim of the present study is to develop and validate of a novel pressure-wire- and microcatheter-free surrogate of coronary flow and resistance derived from a standard coronary angiogram. Angiography derived coronary flow (Qangio) and resistance (Rangio) was prospectively validated in a two-center cohort of patients from Oxford Heart Centre and the Essex Cardiothoracic Centre. Qabs and Rabs were measured during resting and hyperemic conditions with continuous thermodilution using the Rayflow microcatheter. Qangio and Rangio were computed from the diagnostic coronary angiogram in a blinded fashion in resting and hyperemic conditions. A total of 62 patients and 115 vessels were included in the present analysis. The median Qabs at rest was 75 ml/min (53-95) and 151 ml/min (105-203) during hyperemia; Qangio at rest was 84 ml/min (66-108) and 154 ml/min (115-195) during hyperemia. There was a strong correlation between Qabs and Qangio (R = 0,72; p < 0.001, R = 0,86; p < 0.001 respectively) with satisfactory interclass correlation (0.841, 95% CI 0.509-0.957; p = 0.0003). The median Rabs was 1111 mmHg/(L/min) (830-1581.4) at rest and 454 mmHg/(L/min) (348-610) during hyperemia; angiographic resistance (Rangio) was 937.4 mmHg/(L/min) (695.4-1261.9) at rest and 492.4 mmHg/(L/min) (406-697) during hyperemia. There was a strong correlation between Rabs and Rangio in both conditions (R = 0,81; p < 0.001 and R = 0,78; p < 0.001 respectively). The was a good correlation between absolute coronary flow reserve (CFR) and angiography-derived CFR (R = 0,61; p < 0.001) and between absolute microvascular resistance reserve (MRR) and angiography-derived MRR (R = 0,49; p < 0.001).

Development of machine learning models for fractional flow reserve prediction in angiographically intermediate coronary lesions.

BACKGROUND: Fractional flow reserve (FFR) represents the gold standard in guiding the decision to proceed or not with coronary revascularization of angiographically intermediate coronary lesion (AICL). Optical coherence tomography (OCT) allows to carefully characterize coronary plaque morphology and lumen dimensions. OBJECTIVES: We sought to develop machine learning (ML) models based on clinical, angiographic and OCT variables for predicting FFR. METHODS: Data from a multicenter, international, pooled analysis of individual patient's level data from published studies assessing FFR and OCT on the same target AICL were collected through a dedicated database to train (n = 351) and validate (n = 151) six two-class supervised ML models employing 25 clinical, angiographic and OCT variables. RESULTS: A total of 502 coronary lesions in 489 patients were included. The AUC of the six ML models ranged from 0.71 to 0.78, whereas the measured F1 score was from 0.70 to 0.75. The ML algorithms showed moderate sensitivity (range: 0.68-0.77) and specificity (range: 0.59-0.69) in detecting patients with a positive or negative FFR. In the sensitivity analysis, using 0.75 as FFR cut-off, we found a higher AUC (0.78-0.86) and a similar F1 score (range: 0.63-0.76). Specifically, the six ML models showed a higher specificity (0.71-0.84), with a similar sensitivity (0.58-0.80) with respect to 0.80 cut-off. CONCLUSIONS: ML algorithms derived from clinical, angiographic, and OCT parameters can identify patients with a positive or negative FFR.

Optical Coherence Tomography Measures Predicting Fractional Flow Reserve: The OMEF Study.

Background: Optical coherence tomography (OCT) allows to carefully characterize coronary plaque morphology and lumen dimensions. We sought to evaluate the value of OCT in predicting fractional flow reserve (FFR). Methods: We performed a multicenter, international, pooled analysis of individual patient-level data from published studies assessing FFR and OCT on the same vessel. Data from stable or unstable patients who underwent both FFR and OCT of the same coronary artery were collected through a dedicated database. Predefined OCT parameters were minimum lumen area (MLA), percentage area stenosis (%AS), and presence of thrombus or plaque rupture. Primary end point was FFR ≤0.80. Secondary outcome was the incidence of major adverse cardiac events in patients not undergoing revascularization based on negative FFR (>0.80). Results: A total of 502 coronary lesions in 489 patients were included. A significant correlation was observed between OCT-MLA and FFR values (R = 0.525; P < .001), and between OCT-%AS and FFR values (R = -0.482; P < .001). In Receiver operating characteristic analysis, MLA <2.0 mm2 showed a good discriminative power to predict an FFR ≤0.80 (AUC, 0.80), whereas %AS >73% showed a moderate discriminative power (AUC, 0.73). When considering proximal coronary segments, the best OCT cutoff values predicting an FFR ≤0.80 were MLA <3.1 mm2 (AUC, 0.82), and %AS >61% (AUC, 0.84). In patients with a negative FFR not revascularized, the combination of lower MLA and higher %AS had a trend toward worse outcome (which was statistically significant in the analysis restricted to proximal vessels). Conclusions: OCT lumen measures (MLA, %AS) may predict FFR, and different cutoffs are needed for proximal vessels.

DCCAT: Dual-Coordinate Cross-Attention Transformer for thrombus segmentation on coronary OCT.

Acute coronary syndromes (ACS) are one of the leading causes of mortality worldwide, with atherosclerotic plaque rupture and subsequent thrombus formation as the main underlying substrate. Thrombus burden evaluation is important for tailoring treatment therapy and predicting prognosis. Coronary optical coherence tomography (OCT) enables in-vivo visualization of thrombus that cannot otherwise be achieved by other image modalities. However, automatic quantification of thrombus on OCT has not been implemented. The main challenges are due to the variation in location, size and irregularities of thrombus in addition to the small data set. In this paper, we propose a novel dual-coordinate cross-attention transformer network, termed DCCAT, to overcome the above challenges and achieve the first automatic segmentation of thrombus on OCT. Imaging features from both Cartesian and polar coordinates are encoded and fused based on long-range correspondence via multi-head cross-attention mechanism. The dual-coordinate cross-attention block is hierarchically stacked amid convolutional layers at multiple levels, allowing comprehensive feature enhancement. The model was developed based on 5,649 OCT frames from 339 patients and tested using independent external OCT data from 548 frames of 52 patients. DCCAT achieved Dice similarity score (DSC) of 0.706 in segmenting thrombus, which is significantly higher than the CNN-based (0.656) and Transformer-based (0.584) models. We prove that the additional input of polar image not only leverages discriminative features from another coordinate but also improves model robustness for geometrical transformation.Experiment results show that DCCAT achieves competitive performance with only 10% of the total data, highlighting its data efficiency. The proposed dual-coordinate cross-attention design can be easily integrated into other developed Transformer models to boost performance.

Cardiovascular Magnetic Resonance Before Invasive Coronary Angiography in Suspected Non-ST-Segment Elevation Myocardial Infarction.

BACKGROUND: In suspected non-ST-segment elevation myocardial infarction (NSTEMI), this presumed diagnosis may not hold true in all cases, particularly in patients with nonobstructive coronary arteries (NOCA). Additionally, in multivessel coronary artery disease, the presumed infarct-related artery may be incorrect. OBJECTIVES: This study sought to assess the diagnostic utility of cardiac magnetic resonance (CMR) before invasive coronary angiogram (ICA) in suspected NSTEMI. METHODS: A total of 100 consecutive stable patients with suspected acute NSTEMI (70% male, age 62 ± 11 years) prospectively underwent CMR pre-ICA to assess cardiac function (cine), edema (T2-weighted imaging, T1 mapping), and necrosis/scar (late gadolinium enhancement). CMR images were interpreted blinded to ICA findings. The clinical care and ICA teams were blinded to CMR findings until post-ICA. RESULTS: Early CMR (median 33 hours postadmission and 4 hours pre-ICA) confirmed only 52% (52 of 100) of patients had subendocardial infarction, 15% transmural infarction, 18% nonischemic pathologies (myocarditis, takotsubo, and other forms of cardiomyopathies), and 11% normal CMR; 4% were nondiagnostic. Subanalyses according to ICA findings showed that, in patients with obstructive coronary artery disease (73 of 100), CMR confirmed only 84% (61 of 73) had MI, 10% (7 of 73) nonischemic pathologies, and 5% (4 of 73) normal. In patients with NOCA (27 of 100), CMR found MI in only 22% (6 of 27 true MI with NOCA), and reclassified the presumed diagnosis of NSTEMI in 67% (18 of 27: 11 nonischemic pathologies, 7 normal). In patients with CMR-MI and obstructive coronary artery disease (61 of 100), CMR identified a different infarct-related artery in 11% (7 of 61). CONCLUSIONS: In patients presenting with suspected NSTEMI, a CMR-first strategy identified MI in 67%, nonischemic pathologies in 18%, and normal findings in 11%. Accordingly, CMR has the potential to affect at least 50% of all patients by reclassifying their diagnosis or altering their potential management.

Treatment and Care of Patients with ST-Segment Elevation Myocardial Infarction-What Challenges Remain after Three Decades of Primary Percutaneous Coronary Intervention?

Primary percutaneous coronary intervention (pPCI) has revolutionized the prognosis of ST-segment elevation myocardial infarction (STEMI) and is the gold standard treatment. As a result of its success, the number of pPCI centres has expanded worldwide. Despite decades of advancements, clinical outcomes in STEMI patients have plateaued. Out-of-hospital cardiac arrest and cardiogenic shock remain a major cause of high in-hospital mortality, whilst the growing burden of heart failure in long-term STEMI survivors presents a growing problem. Many elements aiming to optimize STEMI treatment are still subject to debate or lack sufficient evidence. This review provides an overview of the most contentious current issues in pPCI in STEMI patients, with an emphasis on unresolved questions and persistent challenges.

Prognostic Value of Microvascular Resistance Reserve After Percutaneous Coronary Intervention in Patients With Myocardial Infarction.

BACKGROUND: The microvascular resistance reserve (MRR) has recently been introduced as a novel index to assess the vasodilatory capacity of the microcirculation, independent of epicardial disease. The prognostic value of MRR in ST-segment elevation myocardial infarction (STEMI) is unknown. OBJECTIVES: The aim of this analysis was to investigate the prognostic value of MRR in patients with STEMI and to compare MRR with cardiovascular magnetic resonance imaging parameters. METHODS: From a pooled analysis of individual patient data from 6 cohorts that measured the index of microcirculatory resistance (IMR) directly after primary percutaneous coronary intervention in patients with STEMI (n = 1,265), a subgroup analysis was performed in patients in whom both MRR and IMR were available. The primary endpoint was the composite of all-cause mortality or hospitalization for heart failure. RESULTS: Both MRR and IMR could be calculated in 446 patients. The optimal cutoff of MRR to predict the primary endpoint in this STEMI population was 1.25. During a median follow-up of 3.1 years (Q1-Q3: 1.5-6.1 years), the composite of all-cause mortality or hospitalization for heart failure occurred in 27.3% and 5.9% of patients (HR: 4.16; 95% CI: 2.31-7.50; P < 0.001) in the low MRR (≤1.25) and high MRR (>1.25) groups, respectively. Both IMR and MRR were independent predictors of the composite of all-cause mortality or hospitalization for heart failure. CONCLUSIONS: MRR measured directly after primary percutaneous coronary intervention was an independent predictor of the composite of all-cause mortality or hospitalization for heart failure during long-term follow-up.

Percutaneous coronary intervention for bifurcation coronary lesions using optimised angiographic guidance: the 18th consensus document from the European Bifurcation Club.

The 2023 European Bifurcation Club (EBC) meeting took place in Warsaw in October, and the latest evidence for the use of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) to optimise percutaneous coronary interventions (PCI) on coronary bifurcation lesions (CBLs) was a major focus. The topic generated deep discussions and general appraisal on the potential benefits of IVUS and OCT in PCI procedures. Nevertheless, despite an increasing recognition of IVUS and OCT capabilities and their recognised central role for guidance in complex CBL and left main PCI, it is expected that angiography will continue to be the primary guidance modality for CBL PCI, principally due to educational and economic barriers. Mindful of the restricted access/adoption of intracoronary imaging for CBL PCI, the EBC board decided to review and describe a series of tips and tricks which can help to optimise angiography-guided PCI for CBLs. The identified key points for achieving an optimal angiography-guided PCI include a thorough analysis of pre-PCI images (computed tomography angiography, multiple angiographic views, quantitative coronary angiography vessel estimation), a systematic application of the technical steps suggested for a given selected technique, an intraprocedural or post-PCI use of stent enhancement and a low threshold for bailout use of intravascular imaging.

Pressure-Controlled Intermittent Coronary Sinus Occlusion (PiCSO) in Acute Myocardial Infarction: The PiCSO-AMI-I Trial.

BACKGROUND: Primary percutaneous coronary intervention (pPCI) has improved clinical outcomes in patients with ST-segment-elevation myocardial infarction. However, as many as 50% of patients still have suboptimal myocardial reperfusion and experience extensive myocardial necrosis. The PiCSO-AMI-I trial (Pressure-Controlled Intermittent Coronary Sinus Occlusion-Acute Myocardial Infarction-I) evaluated whether PiCSO therapy can further reduce myocardial infarct size (IS) in patients undergoing pPCI. METHODS: Patients with anterior ST-segment-elevation myocardial infarction and Thrombolysis in Myocardial Infarction flow 0-1 were randomized at 16 European centers to PiCSO-assisted pPCI or conventional pPCI. The PiCSO Impulse Catheter (8Fr balloon-tipped catheter) was inserted via femoral venous access after antegrade flow restoration of the culprit vessel and before proceeding with stenting. The primary end point was the difference in IS (expressed as a percentage of left ventricular mass) at 5 days by cardiac magnetic resonance. Secondary end points were the extent of microvascular obstruction and intramyocardial hemorrhage at 5 days and IS at 6 months. RESULTS: Among 145 randomized patients, 72 received PiCSO-assisted pPCI and 73 conventional pPCI. No differences were observed in IS at 5 days (27.2%±12.4% versus 28.3%±11.45%; P=0.59) and 6 months (19.2%±10.1% versus 18.8%±7.7%; P=0.83), nor were differences between PiCSO-treated and control patients noted in terms of the occurrence of microvascular obstruction (67.2% versus 64.6%; P=0.85) or intramyocardial hemorrhage (55.7% versus 60%; P=0.72). The study was prematurely discontinued by the sponsor with no further clinical follow-up beyond 6 months. However, up to 6 months of PiCSO use appeared safe with no device-related adverse events. CONCLUSIONS: In this prematurely discontinued randomized trial, PiCSO therapy as an adjunct to pPCI did not reduce IS when compared with conventional pPCI in patients with anterior ST-segment-elevation myocardial infarction. PiCSO use was associated with increased procedural time and contrast but no increase in adverse events up to 6 months. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03625869.

Comparison of troponin and natriuretic peptides in Takotsubo syndrome and acute coronary syndrome: a meta-analysis.

OBJECTIVE: Takotsubo syndrome (TTS) is an acute heart failure syndrome which resembles acute coronary syndrome (ACS) at presentation. Differentiation requires coronary angiography, but where this does not occur immediately, cardiac biomarkers may provide additional utility. We performed a meta-analysis to compare troponin and natriuretic peptides (NPs) in TTS and ACS to determine if differences in biomarker profile can aid diagnosis. METHODS: We searched five literature databases for studies reporting NPs (Brain NP (BNP)/NT-pro-BNP) or troponin I/T in TTS and ACS, identifying 28 studies for troponin/NPs (5618 and 1145 patients, respectively). RESULTS: Troponin was significantly lower in TTS than ACS (standardised mean difference (SMD) -0.86; 95% CI, -1.08 to -0.64; p<0.00001), with an absolute difference of 75 times the upper limit of normal (×ULN) higher in ACS than TTS. Conversely, NPs were significantly higher in TTS (SMD 0.62; 95% CI, 0.44 to 0.80; p<0.00001) and 5.8×ULN greater absolutely. Area under the curve (AUC) for troponin in ACS versus TTS was 0.82 (95% CI, 0.70 to 0.93), and 0.92 (95% CI, 0.80 to 1.00) for ST-segment elevation myocardial infarction versus TTS. For NPs, AUC was 0.69 (95% CI, 0.48 to 0.89). Combination of troponin and NPs with logistic regression did not improve AUC. Recursive Partitioning and Regression Tree analysis calculated a troponin threshold ≥26×ULN that identified 95% cases as ACS where and specificity for ACS were 85.71% and 53.57%, respectively, with 94.32% positive predictive value and 29.40% negative predictive value. CONCLUSIONS: Troponin is lower and NPs higher in TTS versus ACS. Troponin had greater power than NPs at discriminating TTS and ACS, and with troponin ≥26×ULN patients are far more likely to have ACS.

Incidence, Predictors, and Impact of Hospital Readmission After Revascularization for Left Main Coronary Disease.

BACKGROUND: The frequency of and relationship between hospital readmissions and outcomes after revascularization for left main coronary artery disease (LMCAD) are unknown. OBJECTIVES: The purpose of this study was to study the incidence, predictors, and clinical impact of readmissions following percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for LMCAD. METHODS: In the EXCEL (XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial, 1,905 patients with LMCAD were randomized to PCI vs CABG. The cumulative incidence of readmissions was analyzed with multivariable Anderson-Gill and joint frailty models to account for recurrent events and the competing risk of death. The impact of readmission on subsequent mortality within 5-year follow-up was determined in a time-adjusted Cox proportional hazards model. RESULTS: Within 5 years, 1,868 readmissions occurred in 851 of 1,882 (45.2%) hospital survivors (2.2 ± 1.9 per patient with readmission[s], range 1-16), approximately one-half for cardiovascular causes and one-half for noncardiovascular causes (927 [49.6%] and 941 [50.4%], respectively). One or more readmissions occurred in 463 of 942 (48.6%) PCI patients vs 388 of 940 (41.8%) CABG patients (P = 0.003). After multivariable adjustment, PCI remained an independent predictor of readmission (adjusted HR: 1.22; 95% CI: 1.10-1.35; P < 0.0001), along with female sex, comorbidities, and the extent of CAD. Readmission was independently associated with subsequent all-cause death, with interaction testing indicating a higher risk after PCI than CABG (adjusted HR: 5.72; 95% CI: 3.42-9.55 vs adjusted HR: 2.72; 95% CI: 1.64-4.88, respectively; Pint = 0.03). CONCLUSIONS: In the EXCEL trial, readmissions during 5-year follow-up after revascularization for LMCAD were common and more frequent after PCI than CABG. Readmissions were associated with an increased risk of all-cause death, more so after PCI than with CABG.

Comparison of bolus versus continuous thermodilution derived indices of microvascular dysfunction in revascularized coronary syndromes.

Background: The assessment of coronary microvascular dysfunction (CMD) using invasive methods is a field of growing interest, however the preferred method remains debated. Bolus and continuous thermodilution are commonly used methods, but weak agreement has been observed in patients with angina with non-obstructive coronary arteries (ANOCA). This study examined their agreement in revascularized acute coronary syndromes (ACS) and chronic coronary syndromes (CCS) patients. Objective: To compare bolus thermodilution and continuous thermodilution indices of CMD in revascularized ACS and CCS patients and assess their diagnostic agreement at pre-defined cut-off points. Methods: Patients from two centers underwent paired bolus and continuous thermodilution assessments after revascularization. CMD indices were compared between the two methods and their agreements at binary cut-off points were assessed. Results: Ninety-six patients and 116 vessels were included. The mean age was 64 ± 11 years, and 20 (21 %) were female. Overall, weak correlations were observed between the Index of Microcirculatory Resistance (IMR) and continuous thermodilution microvascular resistance (Rµ) (rho = 0.30p = 0.001). The median coronary flow reserve (CFR) from continuous thermodilution (CFRcont) and bolus thermodilution (CFRbolus) were 2.19 (1.76-2.67) and 2.55 (1.50-3.58), respectively (p < 0.001). Weak correlation and agreement were observed between CFRcont and CFRbolus (rho = 0.37, p < 0.001, ICC 0.228 [0.055-0.389]). When assessed at CFR cut-off values of 2.0 and 2.5, the methods disagreed in 41 (35 %) and 45 (39 %) of cases, respectively. Conclusions: There is a significant difference and weak agreement between bolus and continuous thermodilution-derived indices, which must be considered when diagnosing CMD in ACS and CCS patients.

Angiography-Derived Index of Microcirculatory Resistance to Define the Risk of Early Discharge in STEMI.

BACKGROUND: Patients with ST-segment-elevation myocardial infarction but no coronary microvascular injury are at low risk of early cardiovascular complications (ECC). We aim to assess whether nonhyperemic angiography-derived index of microcirculatory resistance (NH-IMRangio) could be a user-friendly tool to identify patients at low risk of ECC, potentially candidates for expedited care pathway and early hospital discharge. METHODS: Retrospective analysis of 2 independent, international, prospective, observational cohorts included 568 patients with ST-segment-elevation myocardial infarction. NH-IMRangio was calculated based on standard coronary angiographic views with 3-dimensional-modeling and computational analysis of the coronary flow. RESULTS: Overall, ECC (a composite of cardiovascular death, cardiogenic shock, acute heart failure, life-threatening arrhythmias, resuscitated cardiac arrest, left ventricular thrombus, post-ST-segment-elevation myocardial infarction mechanical complications, and rehospitalization for acute heart failure or acute myocardial infarction at 30 days follow-up), occurred in 54 (9.3%) patients. NH-IMRangio was significantly correlated with pressure/thermodilution-based index of microcirculatory resistance (r=0.607; P<0.0001) and demonstrated good accuracy in predicting ECC (area under the curve, 0.766 [95% CI, 0.706-0.827]; P<0.0001). Importantly, ECC occurred more frequently in patients with NH-IMRangio ≥40 units (18.1% versus 1.4%; P<0.0001). At multivariable analysis, NH-IMRangio provided incremental prognostic value to conventional clinical, angiographic, and echocardiographic features (adjusted-odds ratio, 14.861 [95% CI, 5.177-42.661]; P<0.0001). NH-IMRangio<40 units showed an excellent negative predictive value (98.6%) in ruling out ECC. Discharging patients with NH-IMRangio<40 units at 48 hours after admission would reduce the total in-hospital stay by 943 days (median 2 [1-4] days per patient). CONCLUSIONS: NH-IMRangio is a valuable risk-stratification tool in patients with ST-segment-elevation myocardial infarction. NH-IMRangio guided strategies to early discharge may contribute to safely shorten hospital stay, optimizing resources utilization.