For anyone researching, some caveats and considerations:
· Try to "weight" studies, based on their relevance, size, and appearance of accuracy.
· Look to see how many patients are in the study. Too few means you must treat the information as anecdotal. It doesn't mean the results are flawed, but it means you may want to consider them as "less compelling," when compared to other, larger studies.
· If the author is strongly espousing an outcome, look more closely at the study results, as they sometimes may reflect what the author wants them to, rather than what is really shown by the data. Some real indicators are when the conclusion appears to be a leap from the data, when parts of results are not listed or seem to be glossed over, or when the word "significant" is used in place of actual numbers or percentages.
· Look for "apples vs apples" in studies. Common approaches, nomenclature, age groups, and methodologies all help you compare studies, or weight their results more appropriately.
· Don't jump at the "right" study. Be very careful of an internal desire to overemphasize a study because it stikes a chord with you for some reason. If you're excited about a result, be all the more careful to validate it independently.
· Age is an immensely important variable in valve studies. Pediatric subjects have extremely pronounced immunological and histological reactions to things that adult bodies do not even seem to notice at all. The appearance is that there is a drop-down of reactivity at about age two, and again after puberty. There is another break point at about age 45, where reactivity drops even further.
· Unconsidered age groups can unintentionally unbalance a study. As an example, the mean age of tissue recipients is older than that of mechanical recipients, so a raw comparison of successes or complications is not an apples-to-apples comparison. If the groups have equivalent results, then the appropriate conclusion might well be that the tissue results are actually superior, when adjusted for age.
· Be on the lookout for incorrect or invalid assumptions, such as "tissue valves are known to last only 6-8 years" or "reoperations are to be avoided as they have an increased risk". Urban Valve Legends can poison a study, if they affect how it's carried out or its conclusions.
· The age of the study itself is important, as we're always looking at historical data. In the fast-changing technology of valve replacement, sometimes even a large, well-run study can be rendered merely anecdotal by the introduction of newer products or techniques (e.g. the newer, amended Ross Procedure technique is only about a decade old, but makes recent Ross operations successful far more often than previous ones).
· Look through as many studies as you can bear to. If you approach them as open-mindedly as you can, you will begin to get a "gut feel" for what the results normally are (an expectation, not a prejudice). Then you can adjudge the validity of variant studies, by focusing on what makes them different. They may be aberrent throwaways, or they may actually wind up being more relevant to your case than the more prevalent studies, depending on what makes them different.
· Does it make sense? You read these forums all the time. These are real people, relating real experiences (albeit not always in a highly scientific manner). If what you're seeing in a study doesn't jive with what you have seen consistently in the forums, try to determine if there is a logical reason why the perception would be different. If you can find no way to reconcile the two, you need to dig deeper, post for more opinions, or make a judgement call.
This is, of course, just my own approach. I apologize if the post sounds didactic. I am trying to learn all I reasonably can about valve replacement issues, and also trying to learn how to learn in the process.
Best wishes,
· Try to "weight" studies, based on their relevance, size, and appearance of accuracy.
· Look to see how many patients are in the study. Too few means you must treat the information as anecdotal. It doesn't mean the results are flawed, but it means you may want to consider them as "less compelling," when compared to other, larger studies.
· If the author is strongly espousing an outcome, look more closely at the study results, as they sometimes may reflect what the author wants them to, rather than what is really shown by the data. Some real indicators are when the conclusion appears to be a leap from the data, when parts of results are not listed or seem to be glossed over, or when the word "significant" is used in place of actual numbers or percentages.
· Look for "apples vs apples" in studies. Common approaches, nomenclature, age groups, and methodologies all help you compare studies, or weight their results more appropriately.
· Don't jump at the "right" study. Be very careful of an internal desire to overemphasize a study because it stikes a chord with you for some reason. If you're excited about a result, be all the more careful to validate it independently.
· Age is an immensely important variable in valve studies. Pediatric subjects have extremely pronounced immunological and histological reactions to things that adult bodies do not even seem to notice at all. The appearance is that there is a drop-down of reactivity at about age two, and again after puberty. There is another break point at about age 45, where reactivity drops even further.
· Unconsidered age groups can unintentionally unbalance a study. As an example, the mean age of tissue recipients is older than that of mechanical recipients, so a raw comparison of successes or complications is not an apples-to-apples comparison. If the groups have equivalent results, then the appropriate conclusion might well be that the tissue results are actually superior, when adjusted for age.
· Be on the lookout for incorrect or invalid assumptions, such as "tissue valves are known to last only 6-8 years" or "reoperations are to be avoided as they have an increased risk". Urban Valve Legends can poison a study, if they affect how it's carried out or its conclusions.
· The age of the study itself is important, as we're always looking at historical data. In the fast-changing technology of valve replacement, sometimes even a large, well-run study can be rendered merely anecdotal by the introduction of newer products or techniques (e.g. the newer, amended Ross Procedure technique is only about a decade old, but makes recent Ross operations successful far more often than previous ones).
· Look through as many studies as you can bear to. If you approach them as open-mindedly as you can, you will begin to get a "gut feel" for what the results normally are (an expectation, not a prejudice). Then you can adjudge the validity of variant studies, by focusing on what makes them different. They may be aberrent throwaways, or they may actually wind up being more relevant to your case than the more prevalent studies, depending on what makes them different.
· Does it make sense? You read these forums all the time. These are real people, relating real experiences (albeit not always in a highly scientific manner). If what you're seeing in a study doesn't jive with what you have seen consistently in the forums, try to determine if there is a logical reason why the perception would be different. If you can find no way to reconcile the two, you need to dig deeper, post for more opinions, or make a judgement call.
This is, of course, just my own approach. I apologize if the post sounds didactic. I am trying to learn all I reasonably can about valve replacement issues, and also trying to learn how to learn in the process.
Best wishes,
