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Coronary Angiography-Derived Index of Microvascular Resistance
Hu Ai1,2, Yundi Feng3, Yanjun Gong4
1Department of Cardiology, Beijing Hospital, Beijing, China.
Insights
A new coronary angiography-derived index of microvascular resistance (caIMR) accurately assesses microvascular diseases without a pressure wire. This method shows high diagnostic performance, potentially increasing adoption for ischemic heart disease patients.
Area of Science:
- Cardiology
- Vascular Physiology
- Diagnostic Imaging
Background:
- Microvascular diseases in coronary circulation are challenging to assess.
- Current methods like wire-derived index of microvascular resistance (IMR) require invasive procedures.
Purpose of the Study:
- To evaluate the diagnostic performance of a novel coronary angiography-derived index of microvascular resistance (caIMR).
- To compare caIMR against the reference standard wire-derived IMR in patients with suspected microvascular dysfunction.
Main Methods:
- Coronary angiography and aortic pressure waves were used to compute caIMR in 56 patients.
- caIMR was assessed against wire-derived IMR (Certus pressure wire) in a blinded manner.
- Diagnostic accuracy, sensitivity, specificity, PPV, and NPV were calculated with a cutoff of 25.
Main Results:
- caIMR demonstrated high diagnostic accuracy (84.2%), sensitivity (86.1%), and specificity (81.0%) compared to IMR.
- A strong correlation (r=0.746) and high AUC (0.919) were observed between caIMR and wire-derived IMR.
- The caIMR method showed potential to eliminate the need for pressure wires.
Conclusions:
- Coronary angiography-derived index of microvascular resistance (caIMR) is a viable, non-invasive tool for assessing coronary microvascular resistance.
- caIMR offers a promising alternative to invasive pressure wire measurements, potentially improving the diagnosis and management of microvascular diseases.
- This technique could enhance the adoption of physiological assessments for patients with ischemic heart disease.
Abstract:
A coronary angiography-derived index of microvascular resistance (caIMR) is proposed for physiological assessment of microvasular diseases in coronary circulation. The aim of the study is to assess diagnostic performance of caIMR, using wire-derived index of microvascular resistance (IMR) as the reference standard. IMR was demonstrated in 56 patients (57 vessels) with stable/unstable angina pectoris and no obstructive coronary arteries in three centers using the Certus pressure wire. Based on the aortic pressure wave and coronary angiograms from two projections, the caIMR was computed and assessed in blinded fashion against the IMR at an independent core laboratory. Diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of the caIMR with a cutoff value of 25 were 84.2% (95% CI: 72.1% to 92.5%), 86.1% (95% CI: 70.5% to 95.3%), 81.0% (95% CI: 58.1% to 94.6%), 88.6% (95% CI: 76.1% to 95.0%), and 77.3% (95% CI: 59.5% to 88.7%) against the IMR with a cutoff value of 25. The receiver-operating curve had area under the curve of 0.919 and the correlation coefficient equaled to 0.746 between caIMR and wire-derived IMR. Hence, caIMR could eliminate the need of a pressure wire, reduce technical error, and potentially increase adoption of physiological assessment of microvascular diseases in patients with ischemic heart disease.
