Myocardial strain shows modest diagnostic yield but may aid identification of patients with a low likelihood of ischemia during vasodilator stress cardiac magnetic resonance.

BACKGROUND AND AIM: Left ventricular dysfunction occurs early in the ischemic cascade. Strain parameters such as global longitudinal strain (GLS) and global circumferential strain (GCS) detect subtle contractile changes, but strain reduction may be observed in situations not related to ischemia. This study assessed whether GLS and GCS may support the identification of a low likelihood of myocardial ischemia in the absence of scarring.

METHODS

Patients were selected from an all-comers registry who underwent vasodilator-perfusion cardiac magnetic resonance imaging (CMR) and showed no evidence of ischemic late gadolinium enhancement. Patients with perfusion deficits were compared with a control group without ischemia and with normal morphological and functional volumetric parameters. GLS and GCS were quantified, and their ability to differentiate ischemic from non-ischemic patients was evaluated using receiver operating characteristic analysis.

RESULTS

Among 1434 patients with perfusion analysis, 451 had normal findings and 112 demonstrated a perfusion defect without LGE. GLS and GCS were significantly reduced in ischemic patients (- 16.66 ± 4.6% vs. - 18.5 ± 3.7%, p < 0.001). GLS and GCS showed only modest discriminatory ability in identifying myocardial ischemia, with AUCs of 0.627 and 0.674, respectively. Optimal cut-off values identified using the Youden index were -18.25% for GLS and -18.85% for GCS. At these thresholds, GLS yielded a sensitivity of 71% and specificity of 52%, and GCS a sensitivity of 65% and specificity of 63%, resulting in high negative predictive values (GLS, 88%; GCS, 88%) but limited overall accuracy.

CONCLUSION

Strain analysis may provide supportive information indicating a low likelihood of ischemia in patients without LGE. Although sensitivity and specificity were only moderate, the consistently high NPV suggests a potential complementary role for strain as part of a multimodal diagnostic work-up, while limited sensitivity precludes its use as a standalone diagnostic marker.