DECisive Intracoronary PHysiology and Imaging in the Evaluation and Reclassification of Non-culprit Lesions in Acute Coronary Syndrome (DECIPHER)

DECisive Intracoronary PHysiology and Imaging in the Evaluation and Reclassification of Non-culprit Lesions in Acute Coronary Syndrome (DECIPHER-NonCulprit)

Despite all advances in diagnostic and therapeutic methods over the past century, ischemic heart disease (IHD) remains a leading cause of mortality and morbidity worldwide. IHD develops as a result of reversible or irreversible impairment of myocardial perfusion in acute or chronic settings. This perfusion abnormality most commonly arises from compromise of epicardial coronary artery patency due to stenosis, occlusion, or vasomotor abnormalities. Structural and/or functional alterations in the microcirculation may also contribute to impaired myocardial perfusion.

Conditions in which myocardial perfusion is acutely compromised are classified as acute coronary syndromes (ACS), whereas reversible ischemia developing on a chronic basis is evaluated under the umbrella of chronic coronary syndromes (CCS). In the assessment of epicardial (macrovascular) or microvascular pathologies leading to ischemia in CCS, angiography, a macroscopic lumenographic method, is often insufficient. Intracoronary pressure and flow measurements are required to determine the impact of angiographically detected epicardial lesions on coronary blood flow, perfusion pressure, and consequently myocardial perfusion. These measurements are referred to as invasive intracoronary physiology (IIP).

Current guidelines recommend that decisions regarding revascularization of intermediate epicardial lesions should be based on IIP. Revascularization guided by IIP is associated with reduced mortality and morbidity, along with a lower stent burden. IIP can be performed using pressure-based, flow-based, or combined strategies. Recent multinational studies indicate that strategies integrating both flow and pressure parameters achieve better clinical outcomes with fewer interventions and reduced stent implantation compared to pressure-only approaches. Indeed, in cases where coronary flow and flow reserve are preserved, abnormalities in pressure parameters alone may not justify revascularization.

Nevertheless, lesions deemed not to be associated with reversible ischemia based on IIP may still pose a risk due to plaque erosion/rupture and subsequent thrombotic cascades that can acutely compromise the lumen. Many acute coronary syndromes arise from lesions that are hemodynamically insignificant (i.e., do not affect flow) and unrelated to reversible ischemia in the CCS setting, but which undergo sudden near-total or total occlusion.

The histopathological characteristics of any coronary lesion can be evaluated using intracoronary imaging techniques. Intracoronary Optical Coherence Tomography (IC-OCT) is a high-resolution, real-time imaging modality that quantitatively assesses lipid-rich plaque content, evaluates the thickness and stability of the fibrous cap separating this content from the lumen, and provides detailed information regarding minimal lumen area, lesion morphology, surface characteristics, presence of erosion, and plaque vulnerability to rupture. IC-OCT can identify lesions that are hemodynamically insignificant yet may benefit from revascularization and have the potential to cause ACS.

Combined evaluation using IC-OCT and IIP enables an integrated assessment of both the relationship with chronic reversible perfusion impairment and the risk of precipitating ACS for each lesion and coronary segment, thereby facilitating optimal revascularization strategies. Despite the available evidence and guideline recommendations in CCS, the use of IC-OCT and IIP in the context of ACS remains limited due to procedural challenges and variability in practical application. These methods are not routinely recommended in guidelines and, in some cases, are even discouraged.

However, the optimal strategy for revascularization of non-culprit lesions in ACS remains uncertain, and no consensus has yet been established. Patients with ACS are at increased risk for recurrent events arising from all coronary lesions. Therefore, accurate evaluation and preventive revascularization strategies for these lesions are expected to provide substantial benefit. Our study aims to reclassify and characterize non-culprit lesions in patients with ACS using combined IC-OCT and IIP assessment.

Study Overview

• Status: Active, not recruiting
• Conditions: Coronary Artery Disease; Fractional Flow Reserve; Acute Coronary Syndromes (ACS); Optic Coherence Tomography
• Intervention / Treatment: Diagnostic test: Intracoronary Physiology; Diagnostic test: Intracoronary imaging

• Study Type: Observational
• Enrollment (Estimated): 40

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Istanbul Mehmet Akif Ersoy Training and Research Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients presented with acute coronary syndrome undergoing successful PCI for the culprit vessel and at least one additional non-culprit vessel were enrolled form the Mehmet Akif Ersoy Hospital Emergency Department

Description

Inclusion Criteria:

• Presenting to the clinic with a diagnosis of Acute Coronary Syndrome.
• Having a significant (total or subtotal) culprit lesion detected during the index angiography procedure and having successfully undergone percutaneous coronary intervention (PCI) for this lesion.
• Having at least one distant non-culprit lesion with moderate stenosis (between 50% and 90%) according to visual angiographic evaluation in coronary arteries (or side branches with a diameter >2.5 mm) that are not major epicardial and not major left main coronary arteries.
• Having TIMI III flow in the vessel containing the non-culprit lesion to be evaluated.
• The patient being able to understand the nature of the study and signing the written informed consent form.
• Patients for whom intracoronary hemodynamic evaluation is planned for treatment planning of the non-culprit lesion after the index procedure.

Exclusion Criteria:

Clinical Exclusion Criteria:

• Advanced renal insufficiency to the extent that the patient cannot tolerate the additional contrast load required for intracoronary imaging (IC-OCT) (e.g., eGFR < 30 mL/min/1.73 m²).
• Known serious allergy or absolute contraindication to the hyperemic agents to be used (e.g., adenosine, papaverine), iodinated contrast agents, or mandatory antiplatelet/anticoagulant therapy.
• Patients presenting to the hospital due to heart failure and cardiogenic shock.
• Additional investigation required due to in-stent restenosis of a non-culprit vessel.
• Patients with blood disorders, bleeding disorders, cancer, end-stage liver or kidney failure, patients with active bleeding, and pregnant women.

Angiographic and Procedural Exclusion Criteria:

• Presence of significant stenosis in the left main coronary artery (LMCA) or the patient having previously undergone coronary artery bypass graft (CABG) surgery.
• Failure of PCI on the culprit lesion in the index procedure, no-reflow, etc. The vessel containing the non-culprit lesion has technical impediments that prevent safe passage of the IC-OCT catheter or pressure/flow wire (e.g., excessive tortuosity, advanced angulation, very dense calcification, or chronic total occlusion [CTO]).

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluation of non-culprit lesion by intracoronary physiology and imaging	The primary endpoint of our study is the evaluation of non-culprit lesions in patients with acute coronary syndrome using intracoronary physiology and imaging. We will determine how many of these non-culprit lesions have hemodynamic significance based on intracoronary physiology. Additionally, intravascular optical coherence tomography will be used to examine how many of these lesions exhibit vulnerable plaque characteristics. Intracoronary Physiology Measurements: Fractional Flow Reserve (FFR): An FFR value of 0.80 will be considered hemodynamically significant epicardial ischemia; Coronary Flow Reserve (CFR): CFR values < 2.0 will be considered impaired hyperemic coronary flow reserve. Intracoronary Optical Coherence Tomography (OCT) Measurements: • Plaque Characterization and Vulnerability Criteria: Thin-capsulated fibroatheroma (fibrous cap thickness < 65 µm); Lipid-rich core (lipid arc > 90°) and at its thinnest point; Minimal lumen area less than 4.0 mm2	From enrollment to the end of the evaluation of non-culprit lesion within 4 weeks

Collaborators and Investigators

• Sponsor: Istanbul Mehmet Akif Ersoy Educational and Training Hospital

Study record dates

Study Major Dates

• Study Start (Actual): April 14, 2026
• Primary Completion (Estimated): April 30, 2027
• Study Completion (Estimated): April 30, 2027

Study Registration Dates

• First Submitted: April 15, 2026
• First Submitted That Met QC Criteria: April 21, 2026
• First Posted (Actual): April 23, 2026

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 21, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: coronary artery disease; acute coronary syndrome
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Heart Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Myocardial Ischemia; Coronary Artery Disease; Acute Coronary Syndrome
• Other Study ID Numbers: DECIPHER-NonCulprit

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No