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.
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?