Sudden death in patients with severe aortic stenosis: observations from the CURRENT AS registry. J Am Heart Assoc. 2018;7:e008397. 35. Rosenhek R, Zilberszac R, Schemper M, et al. Natural history of very severe aortic stenosis. Circulation. 2010;121:151 6. 36. Bergler-Klein J, Klaar U, Heger M, et al. Natriuretic peptides predict symp- tom-free survival and postoperative outcome in severe aortic stenosis. Circulation. 2004;109:2302 8. 37. Gerber IL, Stewart RAH, Legget ME, et al. Increased plasma natriuretic peptide levels reflect symptom onset in aortic stenosis. Circulation. 2003;107:1884 90. 38. Lim P, Monin JL, Monchi M, et al. Predictors of outcome in patients with severe aortic stenosis and normal left ventricular function: role of B-type natriuretic peptide. Eur Heart J. 2004;25:2048 53. 39. Taniguchi T, Morimoto T, Shiomi H, et al. Initial surgical versus conservative strategies in patients with asymptomatic severe aortic stenosis. J Am Coll Cardiol. 2015;66:2827 38. 40. Nishimura S, Izumi C, Nishiga M, et al. Predictors of rapid progression and clinical outcome of asymptomatic severe aortic stenosis. Circ J. 2016;80:1863 9. 41. Freeman RV, Otto CM. Spectrum of calcific aortic valve disease: patho- genesis, disease progression, and treatment strategies. Circulation. 2005;111:3316 26. 42. Horstkotte D, Loogen F. The natural history of aortic valve stenosis. Eur Heart J. 1988;9(suppl E):57 64. 43. Kvidal P, Bergstr m R, H rte LG, et al. Observed and relative survival after aortic valve replacement. J Am Coll Cardiol. 2000;35:747 56. CLINICAL STATEMENTS AND GUIDELINES 44. Murphy ES, Lawson RM, Starr A, et al. Severe aortic stenosis in patients 60 years of age or older: left ventricular function and 10-year survival after valve replacement. Circulation. 1981;64:II184 8. 45. O Brien SM, Shahian DM, Filardo G, et al. The Society of Thoracic Sur- geons 2008 cardiac surgery risk models: part 2 isolated valve surgery. Ann Thorac Surg. 