Global left ventricular load in asymptomatic aortic stenosis: covariates and prognostic implication (the SEAS trial)
1 Institute of Medicine, University of Bergen, Bergen, Norway
2 Haukeland University Hospital, Bergen, Norway
3 Asklepios Clinic St. Georg, Department of Cardiology, Hamburg, Germany
4 Department of Cardiology, Villa Bianca Hospital, Trento, Italy
5 Herz-Zentrum Bad Krozingen, Bad Krozingen, Germany
6 Department of Cardiology, North West Heart Centre, University Hospitals of South Manchester, Manchester, UK
Cardiovascular Ultrasound 2012, 10:43 doi:10.1186/1476-7120-10-43Published: 5 November 2012
Valvuloarterial impedance (Zva) is a measure of global (combined valvular and arterial) load opposing left ventricular (LV) ejection in aortic stenosis (AS). The present study identified covariates and tested the prognostic significance of global LV load in patients with asymptomatic AS.
1418 patients with mild-moderate, asymptomatic AS in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study were followed for a mean of 43±14 months during randomized, placebo-controlled treatment with combined simvastatin 40 mg and ezetimibe 10 mg daily. High global LV load was defined as Zva >5 mm Hg/ml/m2. The impact of baseline global LV load on rate of major cardiovascular (CV) events, aortic valve events and total mortality was assessed in Cox regression models reporting hazard ratio (HR) and 95% Confidence Intervals (CI).
High global LV load was found in 18% (n=252) of patients and associated with female gender, higher age, hypertension, more severe AS and lower ejection fraction (all p<0.05). A total of 476 major CV events, 444 aortic valve events and 132 deaths occurred during follow-up. In multivariate Cox regression analyses, high global LV load predicted higher rate of major CV events (HR 1.35 [95% CI 1.08-1.71], P=0.010) and aortic valve events (HR 1.41 [95% CI 1.12-1.79], P=0.004) independent of hypertension, LV ejection fraction, female gender, age, abnormal LV geometry and AS severity, but failed to predict mortality.
In asymptomatic AS, assessment of global LV load adds complementary information on prognosis to that provided by hypertension or established prognosticators like AS severity and LV ejection fraction.