Tissue characterisation and primary percutaneous coronary intervention guidance using intravascular ultrasound: rationale and design of the SPECTRUM study

Abstract

Introduction: Intravascular ultrasound (IVUS) improves clinical outcome in patients undergoing percutaneous coronary intervention (PCI) but dedicated prospective studies assessing the safety and efficacy of IVUS guidance during primary PCI are lacking.

Methods and analysis: The SPECTRUM study is a prospective investigator-initiated single-centre single-arm observational cohort study aiming to enrol 200 patients presenting with ST-segment elevation myocardial infarct undergoing IVUS-guided primary PCI. IVUS will be performed at baseline, postintervention and postoptimisation (if applicable), using a 40-60 MHz high-definition (HD) system. Baseline tissue characterisation includes the morphological description of culprit lesion plaque characteristics and thrombus as assessed with HD-IVUS. The primary endpoint is target vessel failure at 12 months (defined as a composite of cardiac death, target vessel myocardial infarction and clinically driven target vessel revascularisation). The secondary outcome of interest is IVUS-guided optimisation, defined as IVUS-guided additional balloon dilatation or stent placement. Other endpoints include clinical and procedural outcomes along with post-PCI IVUS findings.

Ethics and dissemination: The protocol of this study was approved by the Ethics Committee of the Erasmus University Medical Center, Rotterdam, the Netherlands. Written informed consent is obtained from all patients. Study findings will be submitted to international peer-reviewed journals in the field of cardiovascular imaging and interventions and will be presented at international scientific meetings.

Trial registration number: NCT05007535.

Keywords: cardiac catheterization; cardiac imaging techniques; myocardial infarction; percutaneous coronary intervention.

Conflict of interest statement

Competing interests: JD received institutional grant/research support from Abbott Vascular, ACIST Medical, Astra Zeneca, Boston Scientific, Medtronic, Microport, Pie Medical and ReCor Medical. Nicolas Van Mieghem received institutional research grant support from Abbott Vascular, Abiomed, Boston Scientific, Daiichi-Sankyo, Edward Lifesciences, Medtronic, and PulseCath. Roberto Diletti is consultant to ACIST Medical. JL received speaking fees from Boston Scientific, Philips Volcano, ACIST Medical, Abbott Vascular and Pie Medical.

© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Protocol for IVUS-guided primary PCI, including the recommended optimisation criteria for IVUS-guided optimisation. IVUS, intravascular ultrasound; MLA, minimal lumen area; PCI, percutaneous coronary intervention.

Figure 2

Culprit lesion, stented segment and reference segments based on preintervention and postintervention IVUS pullback. The culprit lesion segment on the preintervention pullback is matched based on the stented (or treated) segment on the postintervention IVUS pullback. * Or treated segment if only balloon dilatation is performed. DR, distal reference; IVUS, intravascular ultrasound; PR, proximal reference.

Figure 3

Preintervention IVUS findings related to STEMI. Culprit lesion plaque characteristics and thrombus morphology that will be studied with IVUS. (A) Convex calcium (asterisk) that protrudes into the lumen. The arrows indicate the irregular surface. (B) Organised thrombus (asterisk), visualised as an acoustic homogeneous dark appearance with sharp delineation. (C) Minimal lumen area with 360° of subacute thrombus. Subacute thrombus boundaries are less strict and signal attenuation can be appreciated. (D) Plaque rupture (arrow) with blood speckling inside the plaque cavity (asterisk). (E): Soft plaque (arrow) with attenuation (asterisk) in the absence of calcium. IVUS, intravascular ultrasound; STEMI, ST-segment elevation myocardial infarction.

Figure 4

Post-PCI findings that will be studied with IVUS. (A) Residual focal lesion distal from the stented and distal reference segment. The calcified (arrow) and fibrous plaque (asterisk) cause luminal narrowing. (B) A submedial edge dissection (arrow) with blood speckling and accumulation of blood (asterisks) behind the media, defined as a submedial haematoma that compromises the lumen. (C) Malapposition, shown as lumen (asterisks) between malapposed stent struts (small arrows) and the intimal edge. (D) Small stent area due to underexpansion with thrombus protruding into the lumen (arrows) covering multiple stent struts. (E) Large fibrofatty plaque (asterisk) causing a high plaque burden in the proximal reference segment. DR, distal reference; PCI, percutaneous coronary intervention; PR, proximal reference; IVUS, intravascular ultrasound.