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Interventional Diagnostic Procedure: A Practical Guide for the Assessment of Coronary Vascular Function
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Vessel-specific angiography-derived index of microcirculatory resistance in an all-comer population undergoing
Chris Lenselink1, Kim Ricken1, Tsung-Ying Tsai2
1Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands.
Insights
Angiography-derived index of microvascular resistance (angio-IMR) is similar across coronary vessels but lower in women and NSTEMI patients. Higher angio-IMR in NSTEMI patients correlates with worse LV function.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiovascular Research
Background:
- Coronary microvascular dysfunction (CMD) assessment is crucial in cardiac catheterization.
- Angiography-derived index of microvascular resistance (angio-IMR) offers a less invasive method for CMD estimation.
- Discrepancies in CMD across different vessel territories and patient populations require further investigation.
Purpose of the Study:
- To evaluate the differences in angio-IMR across major coronary vessel territories (LAD, RCA, LCX).
- To compare angio-IMR levels between patients with chronic coronary syndrome (CCS) and non-ST-elevation myocardial infarction (NSTEMI).
- To assess the impact of sex on angio-IMR and its association with left ventricular (LV) function.
Main Methods:
- Retrospective analysis of angio-IMR using quantitative flow ratio (QFR) software in the PIONEER-IV trial.
- Inclusion of all-comer patients undergoing coronary angiography for CCS or NSTEMI.
- Comparison of angio-IMR pre- and post-percutaneous coronary intervention (PCI) across vessel territories, indications, and sex, with assessment of LV function via AI-derived echocardiography.
Main Results:
- 80% of patients exhibited baseline angio-IMR indicative of CMD.
- Angio-IMR was consistent across LAD, RCA, and LCX, but increased significantly in LAD post-PCI.
- NSTEMI patients and women demonstrated lower post-PCI angio-IMR, with women showing improved microvascular resistance post-PCI. Higher baseline angio-IMR correlated with worse LV function in NSTEMI patients.
Conclusions:
- Angio-IMR is comparable across major coronary vessels.
- NSTEMI patients and women exhibit lower angio-IMR compared to CCS patients and men, respectively.
- Elevated angio-IMR in NSTEMI patients is linked to diminished LV function, highlighting its clinical relevance.
Background:
Recently, angiography-derived index of microvascular resistance (angio-IMR) has emerged as a less invasive alternative to estimate CMD during cardiac catheterization. Whether CMD differs across vessel territories and populations remains disputed.
Methods:
Consecutive all-comer patients undergoing coronary angiography for chronic coronary syndrome (CCS) or non-ST-elevation myocardial infarction (NSTEMI) enrolled in the PIONEER-IV trial at the University Medical Center Groningen were included. Angio-IMR was retrospectively calculated using quantitative flow ratio (QFR) software in all three major coronary vessel territories pre- and post-PCI, if applicable. Angio-IMR levels were compared between coronary vessels, indication, and sex. The association between angio-IMR and LV function on AI-derived echocardiography analyses were assessed.
Results:
In 220 patients, mean age was 65 ± 9 years, 18.3 % were women, and 20.3 % presented with NSTEMI. CMD was common: 80.0 % had baseline angio-IMR ≥25 mmHg·s/cm. Angio-IMR was similar in the LAD, RCA and LCX in both target and non-target vessels (p > 0.05). In the LAD, angio-IMR increased significantly post-PCI (p < 0.001), while RCA and LCX showed no significant change. Whilst NSTEMI patients showed similar baseline angio-IMR as CCS patients, they had lower post-PCI angio-IMR (p = 0.011). Women had lower average post-PCI angio-IMR (27 vs. 37 mmHg·s/cm, p < 0.001) and showed improved microvascular resistance post-PCI. Angio-IMR was not associated with cardiac function overall, but in NSTEMI patients, higher baseline angio-IMR correlated with worse LV function.
Conclusion:
Angio-IMR is similar in all coronary vessels, but lower in NSTEMI patients than in CCS and lower in women. In NSTEMI patients, higher IMR was associated with worse LV function.
