Friday, January 15, 2010

Pre-Op Cardiovascular Testing for Kidney Transplant Recipients

One of the challenges of taking care of your ESRD patients on the kidney transplant list is deciding on what kind of cardiovascular workup to perform. For obvious reasons, you don't want to be performing a major abdominal surgery on an individual with unstable coronary angina: cardiovascular disease is the most common cause of death with graft function at all times after transplant. Conversely, you also don't want to embark upon a costly, unnecessary, and potentially even harmful (e.g., contrast dye, possibility for atheroembolic disease) cardiac workup on a patient who doesn't have active cardiac issues.

The situation is even more confusing when you realize that patients with ESRD have an exceptionally high rate of coronary artery disease. This study by Ohtake et al performed screening cardiac caths on 30 patients with ESRD--and found that a full 53% of the sample had "angiographically significant CAD", including an even greater percentage (83%) in the subset of patients with ESRD and diabetes! Although it is controversial whether all of these patients would benefit from revascularization therapy, it makes the case that performing a "screening test" (such as ECHO or stress tests) is ESRD is not really worthwhile--you should just go ahead and cath everybody.

That being said, the more common approach to a cardiac workup in a patient being evaluated for kidney transplant is to use such a screening test. The two most popular are probably dobutamine stress echocardiography (which according to this recent AJKD review by Lentine et al has sensititives and specificities ranging from 37% - 95% and 71% - 95%, respectively) and myocardial perfusion studies (sensititives and specificities from 37% - 90% and 40% - 90%, respectively). As you can tell from the wide range of values reported above, the positive and negative predictive values of these tests are worse in the ESRD population than in the general population, making interpretation somewhat tricky. Electron beam CT scan, which determines a "calcium score" within coronary arteries to provide a risk assessment for CAD, has not been rigorously evaluated in the ESRD population.

The KDOQI Guidelines state that dialysis patients on the kidney transplant waiting list should undergo annual performance of non-invasive stress tests, such as those above, if they are considered "high risk"--which they define as having diabetes, known CAD, or having more than 2 traditional risk factors.

6 comments:

Rene C Bakker, The Netherlands said...

These high rates of occult CAD are well know but do not justify invasive workup and pretx correction. No data exist that show that asymptomatic pts with good LV function and occult CAD that was corrected preTx do better in survival than patients with uncorrected occult CAD. The opposite might also be true. Two statements from recent reviews: "-Associations of angiographically-defined coronary artery disease with subsequent survival also are inconsistent, likely because plaque instability is more critical for infarction risk than angiographic stenosis."-Lentine KL Am J Kidney dis jan 2010.
"...there is no clear information currently showing that cardiovascular testing itself reduces the rate of adverse cardiac events after transplantation. Revascularization of coronary artery stenoses is associated with higher morbidity and mortality in all groups with kidney disease than in the general population, with the exception of renal transplant recipients where the mortality is likely to be similar to that of the general population.-Pilmore Nephrology 2009 sept.
We should be careful not to put fragile patients through invasive procedures without proven benefit.

CGGE said...

Such a difficult issue.

I feel like a hypocrite on rounds citing the lack of proven benefit of pre-operative stress testing in a variety of patients then meekly admitting to the team that "the surgeons won't touch him without it though so we might as well get it done."

Suppose this is a bit defeatist and perhaps more backbone is required in order to change practice. Definite food for thought.

Harvey said...

I want to let you know about the upcoming FREE Webinars being offered by the Living Kidney Donors Network (LKDN). The Webinar, titled Having Your Donor Find You is being held on 2 different dates, Tuesday, February 2nd and then again on Monday, February 8th at 7:30 PM Central Time.

Who should attend? This webinar is perfect for people that are in need of a kidney transplant and want to learn more about living kidney donation and how to communicate their need to friends and family. If there is someone that wants to help them spread the word about their need, we call them Advocates, ask them to sign up for the webinar too.

I would greatly appreciate it if you could pass this information along to the appropriate people.

If you have any questions, please do not hesitate to contact me.

To register for one of the Webinars go to:
http://lkdn.org/webinars.html

Regards,


Harvey Mysel
Living Kidney Donors Network
a Not-for-Profit 501(c)3 Organization
www.lkdn.org
http://lkdnblog.blogspot.com
www.twitter.com/harveymysel
harvey@lkdn.org

Harvey said...

I am reaching out to bloggers who are looking to help others who are in need of a kidney transplant. I hope this information could be helpful to you and your followers.

Having Your Donor Find You is a FREE Webinar being offered by the Living Kidney Donors Network (LKDN). It is being held on 2 different dates, Tuesday, February 2nd and then again on Monday, February 8th at 7:30 PM Central Time.

Who should attend? This webinar is perfect for people that are in need of a kidney transplant and want to learn more about living kidney donation and how to communicate their need to friends and family. If there is someone that wants to help them spread the word about their need, we call them Advocates, ask them to sign up for the webinar too.

If you have any questions, please do not hesitate to contact me.

To register for one of the Webinars go to:
http://lkdn.org/webinars.html


Harvey Mysel
Living Kidney Donors Network
a Not-for-Profit 501(c)3 Organization
www.lkdn.org
http://lkdnblog.blogspot.com
www.twitter.com/harveymysel
harvey@lkdn.org

Joel Topf said...

Great comments. If people are interested in how pre-op revascularization fails patients take a look at this VA study published in the NEJM: http://bit.ly/8R7lhG

eric said...
This comment has been removed by the author.