Background and aim .– Alteration of left ventricular global longitudinal strain (GLS) has been found in patients with severe aortic stenosis and preserved left ventricular ejection fraction (LVEF), and interpreted as subtle changes in LV function. Usually, a cut-off of -15% is proposed for GLS. However, high afterload could also modified GLS, and this hypothesis has been less studied.

Methods .– Seventy-nine patients (mean age 75 ± 7) with severe aortic stenosis, preserved LVEF and normal coronary angiography were evaluated by echocardiography the day before and 5 days after valvular surgery. Echocardiography included valvuloarterial impedance (Zva), midwall fractional shortening (MFS) and LGS.

Results .– In the preoperative group (Pre), indexed aortic surface area was 0.38 ± 0.11 cm ² /m ² , mean gradient was 63 ± 17 mmHg, LVEF was 70.9 ± 10%, MFS was 15.6 ± 3.1%, GLS was −16.1 ± 3.4% (measurable in 75 patients), Zva was 4.7 ± 1.4 mmHg/mL/m ² . In the postoperative group (Post), Zva was significantly lower (3.50 ± 0.68 mmHg/mL/m ² ; P < 0.0001), while LVEF (72.1 ± 8.2%), MFS (16.2 ± 4.2%) and GLS (−15.3 ± 3.8%, measurable in 59 patients) were not statistically different. In preoperative patients, GLSpre and ZVapre were significantly correlated ( r = 0.44; P < 0.0001), but not LVEFpre and ZVApre ( r = −0.16; P = 0.1) or MFSpre and ZVApre ( r = −0.17; P = 0.12). In postoperative patients GLSpost and ZVapost were significantly correlated ( r = 0.37; P = 0.007), as well as LVEFpost and ZVApost ( r = −0.28; P = 0.04). In preoperative patients GLS was low in 27 patients (−12.7 ± 1.8%) and normal in 48 patients (−17.9 ± 2.7%). Among the 56 patients with both measurable GLS pre and post, 23 had normal GLS pre and post (−18.5 ± 3.1% and −18.6 ± 2.8%, NS), 15 had low GLS pre and post (−12.3 ± 1.9% and −12.2 ± 1.9%, NS), seven with low GLS pre had normal GLSpost (−13.8 ± 0.8% and −16.8 ± 0.9%, an increase of 22%), and 11 with normal GLS pre had low GLSpost (−16.5 ± 1.7% and −12.1 ± −2.5%, a decrease of 27%).

Patients with low GLSpost ( n = 28) had significant higher Zvapre (5.3 ± 1.5 mmHg/mL/m ² ) and indexed LV mass (124 ± 32 g/m ² ) as compared to patients with normal GLSpost (Zvapre = 4.2 ± 1.0 mmHg/mL/m ² , P < 0.0001; Indexed LVmass = 104 ± 23 g/m ² , P < 0.0001).

Conclusions .– In patients with isolated severe aortic stenosis and normal LVEF, GLS was found to be afterload dependant, both before and after surgery. One third of patients’ changed GLS category between pre and post surgery: improvement in 39% and degradation in 61% of them. However, those modifications do not necessary reflect a change in LV function, and parameters such as afterload indices and LV mass index should be taken into account for interpretation.