Intracoronary electrocardiogram detects coronary microvascular dysfunction and ischemia in patients with no
Erdem Cevik1, Ahmet Tas2, Zeynep G Demirtakan1
1Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey; Department of Cardiology, Istanbul University, Istanbul, Turkey.
Insights
Intracoronary electrocardiogram (icECG) accurately detects coronary microvascular dysfunction (CMD) in INOCA patients, outperforming traditional physiological markers. This method identifies actual ischemia, improving diagnosis and potentially reducing the need for further tests.
Area of Science:
- Cardiology
- Vascular Physiology
- Diagnostic Imaging
Background:
- Coronary microvascular dysfunction (CMD) is a primary cause of ischemia with no obstructive coronary artery disease (INOCA).
- Current CMD diagnosis relies on indirect physiological measures, lacking objective proof of ischemia.
Purpose of the Study:
- To evaluate the accuracy of intracoronary electrocardiogram (icECG) derived hyperemic indices in detecting CMD and reversible ischemia.
- To compare icECG performance against standard physiological indices in INOCA patients.
Main Methods:
- Simultaneous intracoronary electrophysiological (icECG) and Doppler assessment during rest and hyperemia in INOCA patients with proven ischemia.
- Analysis of 60 vessels across 21 patients, categorizing CMD based on coronary flow reserve (CFR) and microvascular resistance (HMR).
Main Results:
- 41 vessels showed CMD, with 26 classified as structural (high HMR) and 15 as functional (normal HMR).
- Absolute ST shift (∆ST) on icECG demonstrated superior diagnostic performance for ischemia (AUC: 0.860) compared to CFR (0.623) and HMR (0.653).
Conclusions:
- icECG accurately detects vessel-specific CMD and ischemia in INOCA patients, outperforming invasive hemodynamic markers.
- icECG provides objective evidence of reversible ischemia, enabling diagnosis during coronary angiography and potentially avoiding additional ischemia testing.
Background:
Coronary microvascular dysfunction (CMD) is the leading cause of ischemia with no obstructive coronary arteries disease (INOCA) disease. Diagnosis of CMD relies on surrogate physiological indices without objective proof of ischemia.
Objectives:
Intracoronary electrocardiogram (icECG) derived hyperemic indices may accurately and objectively detect CMD and reversible ischemia in related territory.
Methods:
INOCA patients with proven ischemia by myocardial perfusion scan (MPS) and completely normal coronary arteries underwent simultaneous intracoronary electrophysiological (icECG) and physiological (intracoronary Doppler) assessment in all 3 coronary arteries during rest and under adenosine induced hyperemia.
Results:
Sixty vessels in 21 patients were included in the final analysis. All patients had at least one vessel with abnormal CFR. 41 vessels had CMD (CFR < 2.5), of which 26 had increased microvascular resistance (structural CMD, HMR > 1.9 mmHg.cm-1.s) and 15 vessels had CMD (CFR < 2.5) with normal microvascular resistance (functional CMD, HMR <= 1.9 mmHg.cm-1.s). Only one-third of the patients (n = 7) had impaired CFR < 2.5 in all 3 epicardial arteries. Absolute ST shift between hyperemia and rest (∆ST) has shown the best diagnostic performance for ischemia (cut-off 0.10 mV, sensitivity: 95%, specificity: 72%, accuracy: 80%, AUC: 0.860) outperforming physiological indices (CFR: 0.623 and HMR: 0.653 DeLong's test P = .0002).
Conclusions:
In INOCA patients, CMD involves coronary artery territories heterogeneously. icECG can accurately detect CMD causing perfusion abnormalities in patients with INOCA outperforming physiological CMD markers, by demonstrating actual ischemia instead of predicting the likelihood of inducible ischemia based on violated surrogate thresholds of blunted flow reserve or increased minimum microvascular resistance.
Condensed Abstract:
In 21 INOCA patients with coronary microvascular dysfunction (CMD) and myocardial perfusion scan proved ischemia, hyperemic indices of intracoronary electrocardiogram (icECG) have accurately detected vessel-specific CMD and resulting perfusion abnormalities & ischemia, outperforming invasive hemodynamic indices. Absolute ST shift between hyperemia and rest (∆ST) has shown the best classification performance for ischemia in no Obstructive Coronary Arteries (AUC: 0.860) outperforming Doppler derived CMD indices (CFR: 0.623 and HMR: 0.653 DeLong's test P = .0002).icECG can be used to diagnose CMD causing perfusion defects by demonstrating actual reversible ischemia at vessel-level during the initial CAG session, obviating the need for further costly ischemia tests.
Clinicaltrials:
GOV: NCT05471739.
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