Abstract 12308: Surgical Results in Low-flow and Normal-flow Severe Aortic Stenosis With Preserved Left Ventricular Function

Abstract

There has been increasing interest in flow conditions in aortic stenosis (AS). Low flow could be an early expression of ventricular failure impairing valve replacement results. The aim of the study is compare surgical outcomes of patients (Pt) with low indexed flow (LF) from normal flow (NF) in severe AS. We studied the cardiac Doppler and clinical data of all symptomatic patients with severe AS (continuity equation aortic valve area <1cm²) who underwent aortic valve replacement (AVR) or AVR plus coronary revascularization (AVR-CABG) in one institution. We considered two groups: LF and NF using a cut point of 35 ml/m². Flow was calculated using left ventricular outflow tract dimensions and pulsed Doppler and then indexed to body surface area. After that we compared baseline characteristics, other markers of AS severity and surgical outcomes between groups. Exclusion criteria: Asymptomatic Pt and AS patients who underwent surgical procedures other than AVR or AVR-CABG. Two hundred and twenty three patients were included from 2003 to 2010 (LF 92 Pt, NF 132 Pt). There were no differences between groups in sex (Men: LF 56.5%, NF 64.9%; Chi p=0.2), age (LF 70.9 years ± 8.1, NF 68.8 years ± 9.3; T-Test p=0.08), ejection fraction (LF 60.2% ± 5.4, NF 61% ± 5.6 T-Test p=0.24) left ventricular diastolic diameter (LF 47.4 mm ± 6 mm, NF 49.8 mm ± 6.1 mm, T-Test p=0.28), aortic peak velocity (LF 4.73 m/s ±0.7, NF 4.6 m/s ±0.66 ,T-Test p=0.17) or indexed left ventricular mass (LF 160 gr/m² ± 43, NF 172 gr/m² ± 49, T-Test p=0.06). Aortic valve area was significantly smaller in LF group (LF 0.52 cm²±0.13, NF 0.74±0.14, p=0.001). Both groups shared similar rates of AVR-CABG (LF 60.9%, NF 52.7%, Chi p=0.225). Perioperative mortality (LF 10.9% , NF 2.3%, Chi p=0.007) and IABP use ( LF 10.9%, NF 1.5%, Chi p=0.02) was higher in LF patients. AVR-CABG perioperative mortality was: LF 10.7%, NF 2.9%, Fisher Test p=0.138 and in AVR: LF 11.1%, NF 1.6%, Fisher Test p=0.138. The only multivariate mortality predictors were age (OR 1.11 95%CI 1.01-1.22) and NF (OR 0.21 95%CI 0.05-0.83). Low flow is an important predictor of perioperative mortality in severe aortic stenosis with preserved left ventricular ejection fraction undergoing AVR or AVR-CABG.