We offer elective aortic replacement ot those we regard as being at high risk. The aortic root dimension and its rate of increase are the best predictors we have. We regard 5.5 cm as the probable upper limit and we are inclined to advocate surgery at an earlier stage in high risk families and in women planning pregnancy. These operations are planned for a calculated gain in life expectancy and it would be reasonable for there to be a degree of centralisation of referral and development of surgical expertise. We use beta-blockade for life, both before and after surgery, in all patients with Marfan's syndrome with aortic root enlargement. The data on which these recommendations are based are incomplete and we can only hope that with an increasing number of carefully documented cases we will refine them and improve upon them in the future. The concept of a "forme fruste" or a "Marfanoid aorta" in the absence of the syndrome is highly questionable so the comments made apply only to patients with Marfan's syndrome--not to other forms of annuloaortic ectasia or other less well characterised forms of aortic root disease.