Abstract
Background.The diagnostic and prognostic utility of coronary flow reserve(CFR) during dipyridamole Stress echo(EchoDipi) has been recognized when the contractile response is positive and even in absence of wall motion abnormalities. Less studied is the behavior of regional longitudinal strain(RLS) and global(GLS) in relation of CFR in the territory of the left anterior descending artery(LADA).
Objectives
Compare the behavior of the Apical LS and GLS with the value of the CFR in the LADA and as a secondary objective to compare these responses with a simultaneous visual analysis of the motility during EchoDipi.
Materials and methods
179 patients (p) were included (age 68.7 ± 7 years). Of them, 113p(65%) were men. At the peak of the effect of Dipi(0.84mg/kg in 4m) the CFR was measured in the distal region of the LADA(Normal Value≥2). The subjects were divided into 2 groups(G): G1: p with CFR of the LAD≥2 and G2 p with LADA CFR < 2. ApRLS was defined as the average of the 4 apical segments, in 4, 3 and 2 apical views, considering any increase in the percentage of deformation as normal. The LGS and wall motility of the 17 segments were evaluated; p with LBBB or wall motion abnormalities were excluded.
Results
Of 179 p, 113p(63.12%) were included in G1 and 66p(36.87%) in G2. G1 were older(65.9 ± 10.27 vs 72.2 ± 9.31,p < 0.02), without significant differences in other clinical characteristics. No differences in the values of LGS and the Ap RLS at rest between G1 and G2 (GLS: G1: -19.8 ± 4.8 vs G2: -20.27 ± 2.6 p = NS; Ap RLS G1: -25.41 ± 4.75 vs G2: -26.73 ± 7.6 p = NS). During EchoDipi GLS and Ap RLS increased in the pts of G1 with a significant worsening in the G2 (SLG: G1: -22.98 ± 4.31 vs G2: -17.82 ± 2.70, p < 0.0001; Ap SLR G1: -28.43 ± 5.6 vs. G2: -22.78 ± 7.41, p < 0.0001). We observed that in 96.7% of p G1 the ApRLS increased strain with the stress meanwhile 95.31% of the G2 decrease(p < 0.0001). Negative predictive value (NPV) :95.6%(CI = 87.8-98.5%), positive predictive value (PPV) =96.8%(CI = 89.0-99.1%).Specificity(E): 97%(CI = 89.9-99.2%),Sensibility(S): 95.2%(CI = 86.9-98.4%). Area Under the ROC curve(AUC)=0.92. The behavior of the GLS showed that 82.8% of the pts of the G1 during EchoDipi increased their Strain values in contrast with 78.8% p of the G2 decrease p < 0.01).NPV 78.8%(CI = 67.5-86.9%),PPV:90.8%(CI = 83.9-94.9%),E:83.9% (CI = 72.8-91.0%),S:87.6%(CI = 80.3-92.5%).AUC ROC= 0.84. The analysis of wall motility showed that 96.46%(109p) of G1 had preserved wall motility, 1 p showed contractility abnormalities and decreased ApRLS. Of the G2, 36p showed conserved contractility during the stress.
Conclusions.There was a close correlation between LADA coronary flow reserve and the contractile reserve evaluated by regional longitudinal strain of the 4 apical segments, which was superior to the use of global longitudinal strain. The Apical Strain showed a better correlation with the LADA coronary flow reserve than with the visual analysis of wall motion.
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