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Noninvasive Index of Microvascular Resistance as a Predictor of Left Ventricular Performance Recovery in Patients with STEMI Undergoing Primary PCI


avatar Mohammad Javad Alemzadeh-Ansari ORCID 1 , avatar Seifollah Abdi ORCID 1 , avatar Bahram Mohebbi ORCID 1 , avatar Saman Rostambeigi ORCID 1 , avatar Azin Alizadehasl ORCID 1 , * , avatar Mohammad Mehdi Peyghambari ORCID 1 , avatar Zahra Hosseini ORCID 1 , avatar Yasaman Khalili ORCID 1

1 Cardiovascular Intervention Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, IR Iran

How to Cite: Alemzadeh-Ansari M J, Abdi S, Mohebbi B, Rostambeigi S, Alizadehasl A, et al. Noninvasive Index of Microvascular Resistance as a Predictor of Left Ventricular Performance Recovery in Patients with STEMI Undergoing Primary PCI. Int Cardio Res J. 2022;16(1):e119268.


International Cardiovascular Research Journal: 16 (1); e119268
Published Online: March 15, 2022
Article Type: Research Article
Received: September 01, 2021
Revised: January 01, 2022
Accepted: January 18, 2022


Background: Coronary microvascular function can predict the infarct size and
Left Ventricular (LV) functional recovery in patients diagnosed with ST-Elevation
Myocardial Infarction (STEMI). Multiple invasive and non-invasive methods are used
to evaluate coronary microvascular function. The Non-invasive Index of Microvascular
Resistance (NiMR) is a method to evaluate microvascular resistance.
Objectives: This study aimed to assess the relationship between NiMR and Left
Ventricular Ejection Fraction (LVEF) measured by Transthoracic Echocardiography
(TTE) in patients with acute STEMI undergoing primary Percutaneous Coronary
Intervention (PCI).
Methods: This prospective observational study was conducted on 39 patients with STEMI.
NiMR was measured instantly after primary PCI. After that, the patients were divided
into two groups based on their NiMR: Group 1 (n = 20) with slighter microvascular
dysfunction (NiMR < 24) and Group 2 (n = 19) with more severe microvascular
dysfunction (NiMR ≥ 24). In the first 24 hours (Echo1) and one month after primary PCI
(Echo2), LVEF and the Global Longitudinal Strain (GLS) were measured by TTE.
Results: The mean age of the patients was 58.0 ± 11.3 years, and 34 ones (87.1%) were
male. In Echo1, there were no significant differences between the two groups regarding
LVEF (39.6 ± 7.8% vs. 38.8 ± 8.6%; P = 0.761) and GLS (−10.2 ± 2.5 vs. −10.9 ± 3.2; P =
0.487). However, LVEF improvement was higher in Group 1 than in Group 2 (Δ LVEF
= 5.8 ± 7.3% in Group 1 vs. Δ LVEF = 1.3 ± 8% in Group 2; P = 0.073), but the difference
was not statistically significant (OR: 2.8, 95% CI: 0.72 - 10.7; P = 0.13). GLS also exhibited
an improvement in both study groups after a month (Δ GLS = 5.4 ± 3.1 in Group 1 vs. Δ
GLS = 2.4±3.2 in Group 2; P = 0.005), but this improvement was statistically significant
only in Group 1 (OR: 5.5, 95% CI: 1.32 - 22.8; P = 0.01).
Conclusions: In patients with lower NiMR values, LV systolic function recovery (defined
by improvement in GLS) was significantly higher one month after STEMI. Thus, NiMR
can be used as an early marker of LV performance recovery after acute STEMI.


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