Myocardial Stunning is Common in Dialysis Patients

By Peter Laird, MD

Myocardial stunning results from episodes of low blood flow to the heart from systemic drops in blood pressure which is now found to be common in dialysis patients.  In a recent study, 64% of dialysis patients tested had significant episodes of myocardial stunning during hemodialysis.

Hemodialysis-induced cardiac injury: determinants and associated outcomes:

RESULTS: Sixty-four percent of patients had significant myocardial stunning during HD. Age, ultrafiltration volumes, intradialytic hypotension, and cardiac troponin-T (cTnT) levels were independent determinants associated with its presence. Myocardial stunning was associated with increased relative mortality at 12 mo (P = 0.019). . . Patients with myocardial stunning who survived 12 mo had significantly lower LV ejection fractions at rest and on HD (P < 0.001).

CONCLUSIONS: HD-induced myocardial stunning is common, and may contribute to the development of heart failure and increased mortality in HD patients. Enhanced understanding of dialysis-induced cardiac injury may provide novel therapeutic targets to reduce currently excessive rates of cardiovascular morbidity and mortality.

The results in a smaller study in pediatric patients is even more astounding, finding 11/12 patients with significant myocardial stunning.  The implications of these findings in a pediatric dialysis population without the age dependent co-morbidities found in many adult dialysis patients implies a treatment effect of the dialysis itself and not an underlying host factor. Pediatric Myocardial Stunning Underscores the Cardiac Toxicity of Conventional Hemodialysis Treatments:

Results: Eleven of 12 patients developed myocardial stunning with varying degrees of compensatory hyperkinesis in unaffected segments, maintaining left ventricular ejection fraction throughout HD. The mean segmental %shortening fraction (SF)_[Overall] and %SF_{[reduction in regional wall motion (RRWM)]} fell during HD (2.19 to 1.77 and 2.72 to 1.37, respectively). Intradialytic BP reduction was significantly associated with mean segmental %SF_[RRWM]

Myocardial stunning resulting from markedly reduced blood flow in the heart tissues is a common and lethal condition that has not received its fair share of attention in the dialysis population.  The simple fact that it is found in the majority of dialysis patients and is associated directly to high ultrafiltration rates demands a verdict.

While I was in practice, letting a patient leave your office in active myocardial ischemia (lack of blood flow to the heart) who subsequently suffered a cardiac event would not be defensible in a malpractice situation.  One of the most frequent reasons for malpractice cases involves failing to diagnose myocardial ischemia in the emergency room setting.

It appears in 2010, that the only place where it is not malpractice or negligence to allow a patient with myocardial ischemia to leave ones clinical care is in the dialysis unit. It now appears that this distressed state is the condition of 60-70%, or more, of dialysis patients as they complete their treatment. It is not a mystery as to why many never return due to sudden cardiac death.  Why is this not a problem to the majority of nephrologists in America?

Comments

[Dori Schatell]

Tell it to CMS, Peter. They're the ones who need to hear this. Or think about a class action suit...

[Peter Laird, MD]

Dear Dori,

I believe CMS already hears the advocacy of people such as yourself, Bill and Lori, yet they will not move until they are compelled. As far as the class action suit, I am actually surprised it has not yet happened. But correct me if I am wrong, I do not believe that you can sue the government in such an instance. Nor can you win such a suit until the standard of practice is breached. That is why I continue to plead with my nephrology colleagues to step up to the plate and change the standard of care here in America to that which is already established in so many other nations to the benefit of all. I simply cannot get past their fiduciary responsibility in leading this much needed change. It truly must come from within the nephrology community. I don't believe CMS will move until the nephrology community moves and reestablishes a new standard of dialysis practice in America.

[Zach]

Seems like the place to bring about change in the standard of care here in the U.S. is to influence the members of the NKF KDOQI. CMS tends to follow their lead.

Has KDIGO taken any position on these issues? It is, after-all, "a global non-profit foundation dedicated to improving the care and outcomes of kidney disease patients worldwide."

[Bill Peckham]

The first step is to convene Technical Expert Panels that inform decisions that lead to National Quality Forums or pilot studies or comparative effectiveness research or trials or ...

The first TEPs were last week, the Data TEPs next month will evaluate what sort of data collection would be needed and how it could be accomplished based on the work product of the first TEPs.

As a participant I signed a NDA about what we actually discussed but I can say it was some heavy lifting. Serious people are taking this seriously.

[Peter Laird, MD]

After living on hemodialysis for over 3 years and reading dialysis articles on a daily basis during that time, I am amazed to find this entire new aspect of dialysis care that I was unaware of until a little over a week ago. Understanding that dialysis patients in general have a higher risk of sudden cardiac death and cardiovascular outcomes is much different that understanding that dialysis is associated with active myocardial ischemia in the majority of patients. To me, all of the other issues that the TEP is looking at are secondary to this central fact leading to myocardial stunning in the majority of patients. Any study looking at HTN control, fluid control, anemia, etc. must take this into account and control for it in any studies done in the future.

How can you reasonably debate survival issues such as the HEMO study on mortality differences if myocardial ischemia and myocardial stunning were not part of the primary end points. I believe that it is the central dialysis issue to be elucidated and solved. It is the biggest game changer that I have learned in the area of dialysis complications. For me, it has answered a lot of questions that I have had professionally and personally. I believe that the more we learn about this complication, the more it will be in the forefront of the dialysis treatment paradigm.

[Bill Peckham]

The TEPs had a specific charge:

• Review and evaluate evidence germane to the development of
  new ESRD quality measures in the specified topic areas,
  
• Propose new ESRD quality measures for the specified topic
  areas,
  
• Provide recommendations and expert input on the
  specifications of new measures

The "specified topic area" most relevant to CHF was "Fluid Weight Management". Coming up with measures is not quite the same as identifying the problem.

[Peter Laird, MD]

The difficulty with the prevalence of myocardial ischemia in dialysis patients is that these episodes are clinically silent compared to the normal population who experience chest pain during myocardial ischemia in most cases. Myocardial ischemia can be detected at the bedside even with out symptoms by common bedside measures such as electrocardiographic monitoring and cardiac enzymes such as troponins which rise quickly in the setting of myocardial ischemia.

CHF in dialysis patients appears to be an end organ result of chronic, silent ischemia as noted in several studies. I am completely perplexed on why myocardial ischemia is not one of the clinical measures in the TEP since myocardial ischemia and myocardial stunning have been a topic in the dialysis literature for over a decade that leads directly to CHF, LVH and sudden cardiac death. Why is CMS and the TEP silent about silent myocardial ischemia when I could lose my medical license for missing just one case of the same thing in the ER setting? Just call me perplexed in Idaho. I just don't understand why this isn't already the central issue of dialysis related complications and sudden cardiac death.

[Peter Laird, MD]

Zach, as always, that is an excellent question on what is the KDIGO position. I will try to look over their information to see if they have already commented on this and let you know if I find anything.

[Bill Peckham]

Peter you're the doctor but isn't it true that not all myocardial ischemia is the same, and as you say, angina's clinical course in dialysis is distinguished from its expected clinical course - in dialysis it's silent.

When people say we need a RCT in more frequent/long dialysis this is the sort of thing that might show up right? If the very nature of dialysis is riskier than improper hydration, then more frequent dialysis may be riskier!

I think that is unlikely but aside from showing evidence of myocardial ischemia in dialysis you'd have to show that the myocardial ischemia was a risk factor independent of other factors ... such as LVH and/or fluid over load. (There would be many other things to control for too but you get the idea)

Then upon showing myocardial ischemia is an independent risk factor you'd have to show an intervention was possible based on an available trigger. At that point you'd be in the TEP ball park.

[Bill Peckham]

One other point - if the myocardial ischemia is shown to be independent of fluid it wouldn't be covered by the TEP I was in. If it is an issue with the bath's K then another TEP may have made a recommendation on K levels. (referencing your post today and the Dutch study)

I do believe CHF is related to fluid. There may be additional issues related to low K baths, there are no doubt plenty of issues to go around. There is good data showing that LVH correlates to mortality and hospitalization risk.