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Updated: May 25, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Pre-perfusion coronary wedge pressure and microvascular obstruction in anterior ST elevation myocardial infarction
Haroun Butt1, Konrad van Beek2, Uzma Sajjad1
1Department of Cardiology, Essex Cardiothoracic Centre, Basildon, UK; Anglia Ruskin School of Medicine and MTRC, Anglia Ruskin University, Chelmsford, Essex, UK.
Background:
Microvascular injury (MVI), commonly assessed on cardiac magnetic resonance (CMR) as microvascular obstruction (MVO), is frequently observed in patients with ST-elevation myocardial infarction (STEMI) despite timely primary percutaneous coronary intervention (PPCI), and is key to adverse left ventricular (LV) remodelling and poor outcomes. Established invasive indices, such as the index of microvascular resistance (IMR), are obtained after reperfusion and therefore do not capture microvascular compromise present during coronary occlusion. Coronary wedge pressure (CWP), obtained during balloon occlusion, is a simple invasive marker of microvascular function, but its clinical value remains uncertain.
Objectives:
To determine whether pre-reperfusion CWP, coronary flow pressure index (CFPI) and related pressure-derived indices are associated with (i) the presence of CMR-defined MVO and (ii) MVO extent in anterior STEMI patients treated with selective intracoronary hypothermia (SIH). Secondary objectives were associations with intramyocardial haemorrhage (IMH) and myocardial salvage index (MSI).
Methods:
In this EUROICE substudy, distal coronary pressure was recorded during culprit LAD occlusion in patients randomised to selective intracoronary hypothermia. Systolic, diastolic and mean CWP, CFPI and outflow time (τ) were derived. CMR at 2-7 days quantified MVO, intramyocardial haemorrhage (IMH) and myocardial salvage index (MSI). Associations were analysed using Spearman correlation, parsimonious multivariable logistic regression, and receiver operating characteristic analysis.
Results:
Of 94 patients randomised to selective intracoronary hypothermia, 82 had paired pre-reperfusion physiology and CMR data available, of whom 65 had interpretable coronary pressure traces. Mean wedge pressure was 21.4 ± 11.0 mmHg, CFPI 0.24 ± 0.11, and τ 5.2 ± 2.6 s. MVO was present in 64% of patients (mean extent 2.7 ± 4.6% of LV mass). Lower CWP and CFPI were associated with MVO presence and extent (CFPI ρ = -0.33, p = 0.008), whereas τ was not. Lower CWP and CFPI were inversely related to IMH, but not to MSI. In complete-case multivariable models, lower CFPI remained associated with MVO presence (adjusted OR 0.91 per 0.01 increase, 95% CI 0.86-0.97, p = 0.002), as did lower mean CWP (adjusted OR 0.91 per 1 mmHg increase, 95% CI 0.85-0.97, p = 0.003). CFPI showed moderate discrimination for MVO, with an AUC of 0.74 (95% CI 0.61-0.87), while mean CWP showed similar discrimination, with an AUC of 0.74 (95% CI 0.61-0.86).
Conclusions:
Lower CWP before reperfusion and CFPI during balloon occlusion were associated with greater MVO and IMH on early CMR in anterior STEMI. These indices support the feasibility of pre-reperfusion physiological phenotyping to aid on-table microvascular risk stratification.
Insights
Pre-reperfusion coronary wedge pressure (CWP) and coronary flow pressure index (CFPI) predict microvascular obstruction (MVO) in ST-elevation myocardial infarction (STEMI) patients. These simple invasive measures aid on-table risk stratification for better patient outcomes.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Medical Imaging
Background:
- Microvascular injury (MVI), assessed as microvascular obstruction (MVO) on cardiac magnetic resonance (CMR), is common in ST-elevation myocardial infarction (STEMI) despite primary percutaneous coronary intervention (PPCI).
- MVI contributes to adverse left ventricular remodeling and poor outcomes.
- Current invasive indices like index of microvascular resistance (IMR) are measured post-reperfusion, failing to capture microvascular compromise during occlusion.
Purpose of the Study:
- To assess if pre-reperfusion coronary wedge pressure (CWP) and coronary flow pressure index (CFPI) correlate with CMR-defined MVO presence and extent in anterior STEMI patients.
- To investigate associations with intramyocardial hemorrhage (IMH) and myocardial salvage index (MSI).
Main Methods:
- Analysis of a EUROICE substudy involving STEMI patients randomized to selective intracoronary hypothermia.
- Measurement of distal coronary pressure during culprit left anterior descending (LAD) occlusion to derive CWP and CFPI.
- Quantification of MVO, IMH, and MSI using CMR 2-7 days post-procedure.
Main Results:
- Lower CWP and CFPI were significantly associated with the presence and extent of MVO (CFPI: ρ = -0.33, p = 0.008).
- These indices also showed an inverse relationship with IMH but not MSI.
- Multivariable analysis confirmed lower CFPI (aOR 0.91) and mean CWP (aOR 0.91) as independent predictors of MVO presence, with moderate discrimination (AUC 0.74 for both).
Conclusions:
- Pre-reperfusion CWP and CFPI are associated with increased MVO and IMH on early CMR in anterior STEMI.
- These findings highlight the feasibility of using pre-reperfusion physiological measurements for on-table microvascular risk stratification.
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