<s>[INST] my 84 yr old mother who has moderate to severe vascular dementia has tmo leaky heart valves. she has already had a valve replaced 5 yrs ago which although successful increased her dementia a lot so surgery not an option. how long do you think my mums lifespan will be? [/INST] Hello, Vascular dementia doesn't influence your mothers' lifespan that much if properly cared for she can live for many years. What might be more problematic and risk her life would be her heart issues.  It is hard to make predictions on that regard though as you don't provide much information on the valves involved, heart residual function, other commonly associated phenomena such as arrhythmia and medications she's taking. Hope I have answered your query. Let me know if I can assist you further. Take care Chat Doctor.  </s>