Objective

To characterize the alteration in quantification of global left ventricular (LV) strain by cardiovascular magnetic resonance(CMR) feature tracking after acute ST-elevation myocardial infarction（STEMI） before LV remodeling, and to explore the relation to microvascular obstruction (MVO).

Methods

The prospective study enrolled 32 patients with STEMI successfully treated with primary PCI who underwent CMR after 3-5days (baseline) and 4-6 months (follow-up). Cine imaging and late gadolinium enhancement(LGE) was performed at 3.0 T MR. Longitudinal global strains(GLS),circumferential global strains (GCS),global radial strains(GRS) and cardiac volume were measured by CVI 42 software based on cine sequences. MVO was assessed based on LGE sequence. According to the existence of MVO or not, all patients were divided into MVO(+) group and MVO(-) group. Mean values of GLS, GCS and GRS were compared between the two groups of patients using an independent-samples t-test. Means of baseline and follow-up measurements were compared using a paired t-test.

Results

In this study, none of the patients had LV remodeling, according to the end-systolic volume improvement no more than 15%. Seventeen patients were classified as MVO(-) and 15 patients as MVO(+)[Age:(57.82±10.53)year vs.（55.07±10.42）year, P=0.774；BMI:(24.38±2.85)kg/m² vs.（27.06±3.13）kg/m²，P=0.698]. At baseline, there were no significant differences of GRS, GCS and GLS between the two groups (P=0.47,0.64 and 0.71). At follow-up, the GRS and GCS between MVO(+) and MVO(-) still make no significant differences (P=0.06, 0.12), while the GLS mean values of MVO(+) group significantly lower than that of MVO(-) group [(-14.10±0.51)%vs. (-16.35±0.75)%, P=0.048]. From baseline to 4-6 follow-up, the GRS, GCS and GLS of the two groups were all increased {MVO(-): [(34.51±8.52)% vs. (34.65±9.07)% , P =0.007 ], [(-16.91±3.14)% vs.( -18.13±3.64)% , P=0.038 ], [(-15.04±2.53)%vs. (-16.35 ±3.08)%,P=0.010];MVO(+):[(29.12±6.84)%vs. (30.61±5.68)% ,P=0.101], [(-14.27±3.04)%vs.( -16.33±0.66,)%, P=0.014 )], [(-11.97±2.21)%vs.(-14.10 ±1.98）% , P=0.657 ]}.

Conclusions

For acute STEMI patients without LV remodeling in 4-6 months after PCI, the GRS, GCS and GLS of LV were all increased irrespective of MVO existed or not, and the changes of GLS in group with MVO was more obvious. Which may be the evidence of LV early remodeling.

Acknowledgements

No acknowledgement found.