Reduced Left Ventricular Global Longitudinal Strain in the Coronary Slow Flow Phenomenon: A Systematic Review and Meta-Analysis

Mahin  Seifi Alan; Kobra   Hosseini; Sanaz  Seifi Alan; Zahra  Mirzaei; Peyman  Saeedi; Soroush  Bahrami; Vahid  Shahnavaz; Haniyeh  Rashidi; Mahnaz  Seifi Alan; Hadith  Rastad

doi:10.18502/jthc.v20i4.20747

Mahin Seifi Alan Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Kobra Hosseini Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Sanaz Seifi Alan Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Zahra Mirzaei Cardiovascular Research Center, Alborz University of Medical Sciences, Karaj, Iran.
Peyman Saeedi Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Soroush Bahrami Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Vahid Shahnavaz Cardiovascular Research Center, Alborz University of Medical Sciences, Karaj, Iran.
Haniyeh Rashidi Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Mahnaz Seifi Alan Clinical Research and Development Center of the Kamali Hospital, Alborz University of Medical Sciences, Karaj, Iran.
Hadith Rastad Imperial Clinical Trials Unit, Imperial College London, London, UK.

DOI: https://doi.org/10.18502/jthc.v20i4.20747

Keywords: Coronary Slow Flow Phenomenon; Left Ventricle Global Longitudinal Strain; Speckle-Tracking Echocardiography

Abstract

Background: The coronary slow flow phenomenon (CSFP) involves delayed coronary artery filling without obstruction and is associated with angina and myocardial ischemia. This meta-analysis assessed the link between CSFP and impaired left ventricular global longitudinal strain (LVGLS), a marker of subclinical myocardial dysfunction.

Methods: A systematic search (PubMed, Embase, Scopus up to January 2025) identified 18 observational studies comparing LVGLS and layer-specific strain in patients with CSFP vs controls with normal coronary flow.

Results: Patients with CSFP showed significantly reduced LVGLS vs controls (SMD, 1.22; 95% CI, 0.69 to 1.75). Layer-specific analysis revealed impairment across all myocardial layers, most pronounced in the endocardium (SMD, 0.79; 95% CI, 0.21 to 1.38). While left ventricular ejection fraction (LVEF) was preserved, LVGLS demonstrated moderate-to-high diagnostic accuracy for CSFP (AUC, 0.80; 95% CI, 0.66 to 0.95). Reduced LVGLS independently predicted CSFP (adjusted OR, 1.43; 95% CI, 1.19 to 1.46). Exercise stress effects on LVGLS were inconsistent.

Conclusion: CSFP is associated with impaired LVGLS, particularly in the endocardial layer, despite preserved LVEF. LVGLS may serve as a noninvasive marker for subclinical dysfunction in CSFP.