Diagnostic significance of myocardial longitudinal strain in patients with suspected MINOCA (myocardial infarction with non-obstructive coronary arteries)
Abstract
In patients with acute myocardial injury and non-obstructive coronary arteries,differentiating myocardial infarction with non-obstructive coronary arteries (MINOCA) from myocarditis or Takotsubo syndrome is challenging. Although cardiac magnetic resonance (CMR) is the diagnostic gold standard, it is often unavailable in the acute phase. Speckle tracking echocardiography (STE) can provide early diagnostic clues through longitudinal strain (LS) analysis. This study evaluated the diagnostic accuracy of LS parameters and their correlation with CMR findings. Consecutive patients with acute myocardial injury and unobstructed coronaries from the AMIPE registry (2021–2023) were analyzed. All underwent 2D echocardiography with STE within 24 h and CMR within 14 days. Segmental longitudinal strain (SLS) was calculated using a 16-segment model. A coronary pattern (CP) was defined as two contiguous segments within the same coronary territory showing the least negative strain. Associations between LS and CMR findings were assessed, and predictors of ischemic pattern were identified by multivariable logistic regression. Among 189 patients, CP was found in 61 (32%). CP+ patients had lower LSmin (−4.6% vs −10.5%, p<0.001) and greater LS difference (p<0.001) than CP− subjects. All CP+ cases showed CMR abnormalities, mainly ischemic late gadolinium enhancement (54%), while 40% of CP− patients had normal CMR. CP independently predicted an ischemic pattern (OR 9.8, 95% CI 2.6–37.3, p<0.001), as did LSmin (OR 1.4, 95% CI 1.1–1.6, p<0.001), even when no visual regional wall motion abnormalities were detected. ROC analysis identified LSmin ≥ −7.6% as the optimal cutoff (AUC 0.73; sensitivity 85%; specificity 62%). In suspected MINOCA, SLS adds diagnostic value beyond conventional echocardiography. CP and LSmin ≥ −7.6% independently predict ischemic injury on CMR. STE may represent a rapid, accessible, and cost-effective adjunct to CMR in this clinical setting.Boxplot