Hi Pizza-fan,
I read over the study that you posted. The objecitve of the study was to develop a statistical (and thus unbiased) model of patient outcomes based on the type of AVR undergone. They simulated different age groups because, as we know, operational outcome, valve durability, and event-free living all have correlations (be they positive or negative) with the age of the patient undergoing AVR. Overall, I applaud their attempt to create this model. However, very few conclusions can be drawn from this model for a number of reasons:
1. One would certainly expect an AVR patient to have a lower life-span than an otherwise healthy individual. OHS and then having a non-native aortic valve both carry increased risks of mortality. The researchers found that average life expectancy for valve recipients was shorter but this could only be partially explained by valve-related issues. Apparently, valve patients have a higher risk of other non-related valve health problems than the general population. Unfortunately, the authors gave no explanation for why this might be the case.
They had to collect data to calibrate their simulation model, however, they give very little information on what patients were used and which were not. We all know that many, if not most, aortic valve patients do not just have isolated aortic valve disease. Some have aortic valve disease because of rheumatic fever, others because of radiation from cancer therapy, others because of a wide-ranging syndrome like Marfan's, not too mention a myriad of other reasons. Other AVR patients have issues with multiple valves. Being in any of these aforementioned categories would lower one's life expectancy compared to someone like yourself who has isolated aortic valve disease. If one was to remove all of those patients who had concomitant health problems from the model it is quite obvious that the life expectancy for aortic valve replacement patients would be only slightly less than an average healthy individual of the same age. Until the patients are grouped according to other risk factors the study remains mostly useless to both patients and health care providers. In fact, it could be misleading to many patients who read it and do not see the clear caveats issued by the authors. They know that there study should not be taken at face value as many patients who read it would end up taking it.
2. The outcomes used to calibrate the simulation were based on surgical techniques and non-invasive cardiac medicine techniques that have been significantly improved upon in the past ten years. Operative and re-operative mortality and morbidity rates continue to decrease every year. Non-invasive techniques continue to improve every year: new medicines come out and doctors learn how to more correctly treat the patient using these new medicines and existing ones every year. Any valve study which takes patient data from the 90s and even the 80s, which this one does, must be viewed with more omptimism then it puts forth due to these significant increases in helath care outcomes for AVR patients in the past 10-20 years.
All in all, of course your life expecatncy is reduced after AVR compared to a healthy individual of the same age. Anyone who says otherwise is deliberately hiding from the truth. Your life expectancy is significantly reduced if you have concomitant health problems (whether or not they were the causation) associated with your aortic valve disease. However, individuals who are otherwise healthly like yourself should expect, on average, to have a life-span approaching (but not reaching) that of a healthy individual of the same age.
Brad
