For Patients With Myocardial Infarction and Multiple Vessel: Testing if Ultrasound (UFR) Can Guide All Needed Treatment in One Procedure, Avoiding a Return Hospital Visit for a Second Operation.

Overview

Brief Summary The Purpose of the Study : The purpose of this study is to find a safe and reliable "one-stop" solution for treating heart attack patients who have multiple blocked arteries. Currently, doctors face a dilemma: Testing these other blockages during the heart attack procedure is often unreliable. The most accurate method requires asking the patient to return 30 days later for a second invasive procedure, which is a significant burden. The Study's Hypothesis : We are testing a new tool called UFR, which uses ultrasound images to measure blockages. Our hypothesis (or "educated guess") is that this new UFR tool is not affected by the body's stress during a heart attack and can provide a true, reliable measurement right away. The Question the Study is Trying to Answer ： The main question this study is trying to answer is: Can the new "one-stop" UFR tool, used during the initial heart attack procedure, accurately predict which blockages are truly serious... thereby eliminating the need for patients to return for a second procedure 30 days later? Researchers will also follow 200 patients for one year, using advanced scans (like UFR, standard tests, and MRI), to better understand how the heart and arteries heal and change over time.

The ACT-EVOLVE Study: A Prospective, Longitudinal, Multi-modal Study Evaluating the Utility of Acute Phase UFR (IVUS-FFR) to Predict Functional Significance in the Stable Phase for Patients With Acute Coronary Syndrome (ACS). Study Rationale and Background: In patients with Acute Coronary Syndrome (ACS) and multi-vessel disease (MVD), complete revascularization (CR) is proven to improve outcomes (e.g., COMPLETE trial, Level A evidence). However, a significant "how-to paradox" exists. Physiologically-guided CR using pressure-wire FFR (pFFR) during the acute index procedure (T0) has failed to show superiority over angiography (e.g., FLOWER-MI trial).This is largely attributed to "functional drift": the acute phase is marked by significant microvascular dysfunction (CMD) and high Index of Microcirculatory Resistance (IMR), especially in STEMI. This interference renders T0 pFFR unreliable, leading to false negatives (over-estimation of FFR).While a staged procedure at a stable timepoint (T1, 30 days) provides a reliable physiological assessment, this strategy faces severe real-world challenges, including high costs, poor patient compliance, and the risk of events during the waiting period.This study hypothesizes that UFR (IVUS-FFR)-a "virtual" FFR derived from IVUS structure and computational fluid dynamics (CFD)-is immune to the acute-phase physiological disturbances (CMD). We hypothesize that T0 UFR can accurately and reliably predict the "gold standard" stable-state pFFR at T1, thus offering a "one-stop shop" solution to guide CR during the index procedure. Study Objectives:Primary Objective: To assess the diagnostic accuracy (sensitivity, specificity, PPV, NPV, and correlation) of UFR measured in non-culprit vessels (NCV) during the acute phase (T0), compared to the gold-standard pFFR (threshold ≤ 0.80) measured in the stable phase (T1, 30 days). Key Secondary Objectives:Functional Drift (Head-to-Head): To quantify and compare the "functional re-classification rate" of physiological indices (pFFR, RFR) from T0 to T1 in two pre-specified cohorts: STEMI vs. High-Risk NSTEMI."Structure-Function-Tissue" Coupling (1): To correlate acute culprit vessel (CV) microcirculatory damage (T0 IMR) with sub-acute myocardial tissue injury (MVO and infarct size) measured by T-CMR (3-5 days)."Structure-Function-Tissue" Coupling (2): To analyze the relationship between T0 PCI optimization quality (by post-PCI IVUS criteria) and immediate post-PCI microcirculatory damage (T0 IMR) in the culprit vessel.Longitudinal Vessel Evolution: To assess the long-term (T0 vs. T2) stability of pFFR and UFR in the stented culprit vessel, and to track the functional and structural progression of untreated NCVs (T1 to T2).Prognostic Value: To evaluate the prognostic value of T1 NCV functional status (threshold ≤ 0.80) on 1-year MACE. Study Design:This is a prospective, longitudinal, observational registry. All key data (physiology, imaging, and CMR) will be analyzed by independent, blinded core laboratories (Physiology Core Lab, Imaging Core Lab, CMR Core Lab). A Clinical Events Committee (CEC) will adjudicate all clinical endpoints. Study Population:Sample Size: N = 200 patients. Target Population: Patients presenting with ACS (STEMI or High-Risk NSTEMI) who have successfully undergone PCI of the culprit vessel and are found to have MVD.MVD Definition: At least one NCV with a 50-90% diameter stenosis by visual estimation. Pre-specified Stratification:Cohort A: STEMI (N ≈ 100)Cohort B: High-Risk NSTEMI (N ≈ 100)Study Procedures and Timeline:This study involves a systematic, longitudinal assessment at four key timepoints:T0 (Acute Phase - Index Procedure):Culprit Vessel (CV): After successful PCI, post-PCI IVUS, pFFR, RFR, and IMR are measured.Non-Culprit Vessel (NCV): All target NCVs (50-90%) undergo a baseline assessment with IVUS (for UFR calculation) and physiological measurements (T0 pFFR, T0 RFR, T0 IMR). Key Action: No intervention is performed on the NCV at T0.T-CMR (Sub-Acute Phase - 3-5 Days Post-PCI):Patients (particularly the STEMI cohort) undergo a standardized Cardiac MRI (CMR) to quantify Left Ventricular Ejection Fraction (LVEF), infarct size, and Microvascular Obstruction (MVO).T1 (Stable Phase - 30 Days Post-PCI):Patients return for a planned, invasive follow-up procedure.NCV: The same NCVs assessed at T0 are re-evaluated.Gold Standard Assessment: T1 pFFR and T1 RFR are measured.Clinical Decision: The T1 pFFR result is unblinded. If T1 pFFR threshold ≤ 0.80, the patient undergoes PCI as per guidelines. If \> 0.80, the patient continues on optimal medical therapy (OMT).T2 (Long-Term Follow-up - 1 Year):Clinical Follow-up: Assessment for 1-year MACE (cardiac death, target-vessel MI, clinically-driven revascularization).Invasive Follow-up: A planned (per-protocol) 1-year invasive angiographic, IVUS, and functional assessment of both the CV (for in-stent analysis) and any untreated NCV (for disease progression). Expected Impact:The ACT-EVOLVE registry is designed to provide the first prospective, gold-standard-controlled evidence to validate UFR as a "one-stop" tool for guiding complete revascularization in the acute ACS setting. By directly comparing STEMI and NSTEMI, and building a unique T0-T1-T2 longitudinal database, this study aims to solve the "ultimate dilemma" in ACS-MVD management, potentially replacing the logistically challenging staged-procedure strategy.