Exercise Testing

Mark- Good comments as always. The point I was trying to make is that the role of CPX is infrequently included in cardiology guideline statements. Case in point, see the 2020 ACC/AHA Guideline for the Management of Patient with Valvular Heart Disease. click here for pdf CPX is mentioned once in this statement and oxygen consumption is mentioned twice.

Hi Clinton and thank you for your always well thought out responses and questions. I think where we have got off track is when CPX testing is more valuable, not if it actually pinpoints the issue. I do agree that using just some of the abnormal variables at face value has its problems and I would never use a single variable such as O2 pulse to suggest a cardiac limitation by itself and certainly not specific to one cardiac condition. You are also a bit limited in being able to respond because I have not given you the entire scenario and my thought processes that led me to my suggestion to the cardiologist that his valve disease may be the biggest concern, but even during that discussion we could not totally eliminate the range of possibilities from microvascular ischemia, obstructive CAD, pulmonary htn, heart failure, etc. We did talk however, that if these results came to light earlier, he would have likely taken him to catheterization much sooner and figured out his aortic valve was considerably worse than thought. So, in this case he did have ST changes, low peak VO2, borderline low AT, low O2 pulse and abnormal graphically, low VO2/workrate relationship and symptoms different than his prior angina, but consistent with valve disease.

I will also say that over the past 6 years that I have been following the research and participating in multiple practicums that the evidence is starting to add up that some of these variables are becoming more valuable in diagnosis and not just prognosis of different conditions, although taken individually, are still not very accurate. But, taken in the overall clinical scenario, can be more telling than what we have been able to use CPX in the past.

I also had the added visit to consult on his conditions and symptoms and had a very clear picture of over 20 visits (including testing) that gave me an advantage to when it came down to help interpret his results, I could help the cardiologist come up with the plan that revealed his issues.

I have often discussed with people in our profession that sometimes we get to stuck in the past and just what numbers and results tell us in a silo. It is case studies like this that can help highlight how much more valuable we are beyond being able to interpret data points and just make out reports.

I will also admit that I have a somewhat unique position here and have advantages and very established relationships with our physicians that allow me to work to my full scope of knowledge, experience and training, but yet also staying within reasonable boundaries.

Recommendations for clinical exercise testing in various populations can be found in chapter 5 on GETP10 if you wanted to switch up your population in your case study (if possible). this might help make it more applicable but still make your point that this testing can be more effective other than a last line resort

Mark- When you say CPX revealed the cardiac limitation, are you referring to the response in O2 pulse, a low anaerobic threshold, and/or other CPX measures? Or are you referring to quantifying the low exercise capacity with measured VO2? I ask this because I'd say a big part of the issue you are describing is due to a lack of empirical data supporting O2 pulse and anaerobic threshold as measures of cardiac dysfunction. As a result, CPX is not mentioned in guideline statements aimed at management of valve disease.

I am preparing a presentation on a case study where an 82 year old man with fatigue and dyspnea on exertion ultimately needed a TAVR, but went through several months of endless testing, labs, and specialty visits until the cardiopulmonary exercise test revealed cardiac limitation to exercise. My take on the matter is what if CPX was used early in the evaluation and pointed towards a cardiac cause and thus cut out a lot of unnecessary visits and testing and got to the solution much quicker.

This seems to be a trend around here that CPX is used when everything else fails to come up with the culprit instead of early in the evaluation to help drive where any additional investigation might go, or maybe reveals the problem right away.

Is this similar to your experiences? Or do you all use CPX earlier in the process?