Sudden Cardiac Death Rate Remains High Among Hemodialysis Patients
A number of problems may contribute to sudden cardiac deaths in this population.
ORLANDO, Fla. — Fewer hemodialysis patients are dying from cardiovascular (CV) causes overall, researchers reported at the National Kidney Foundation's 2017 Spring Clinical Meetings. But progress is needed to reduce the rate of sudden cardiac deaths (SCD).
“CV death rates due to causes other than SCD have decreased markedly in dialysis patients over the past two decades, but little improvement has occurred for SCD,” stated lead study author Charles Herzog, MD, of the University of Minnesota in Minneapolis, on behalf of Peer Kidney Care Initiative investigators. “Future improvements in the overall CV death rates will require advances in preventing SCD.”
During 1996 to 2013, the rate of total CV deaths fell 42.5% from 12 to 7 per 100 persons per year, according to an analysis of Medicare data. However, after a modest decline from 2004 to 2010, SCD deaths remained constant at approximately 5 per 100 patients per year. SCD continued to be a major contributor to CV deaths, accounting for about 61% of such deaths in 2009 and 73% in 2013.
Meanwhile, hospital admissions for arrhythmias, a precursor to SCD, remained unchanged from 2004 to 2013, at approximately 4.5 admissions per 100 patients per year.
A number of problems may contribute to SCD in this population, according to Dr Herzog. Obstructive coronary artery disease, left ventricular hypertrophy, and alterations in myocardial structure and function (e.g., endothelial dysfunction, interstitial fibrosis, decreased perfusion reserve, and diminished ischemia tolerance) are possible contributors. Additional factors specific to hemodialysis include rapid electrolyte shifts, low-potassium dialysate with hyperkalemia, and dialysis vintage.
“Although speculative, I think accurate risk stratification may ultimately rely on a combination of echocardiography, electrocardiography, and cardiac biomarkers (such as high sensitivity cardiac troponins),” Dr Herzog told Renal & Urology News. “The KDOQI 2005 cardiovascular practice guidelines still work pretty well. What is still missing is an effective therapy to reduce SCD, which in my opinion is a direct consequence of the ‘cardiomyopathy of CKD,' the left ventricular hypertrophy and myocardial fibrosis that contribute to arrhythmic death.
“I welcome seeing interventions that actually prevent the development of left ventricular hypertrophy and myocardial fibrosis,” he continued. “It's potentially a long list that requires testing in randomized clinical trials. I personally think there is a role for ‘device' therapy in preventing SCD in dialysis patients.”
Lastly, he said he believes physicians need to adequately inform patients about the risks of SCD, particularly at dialysis initiation.
With regard to future research, the team encouraged new studies on the timing of cardiovascular events, including whether cardiovascular deaths and arrhythmia-related admissions occur on HD or post-HD days, or before or after a dialysis session. How constituent electrolytes of the dialysis bath affect dialyzability of potentially anti-arrhythmic drugs such as beta-blockers also needs to be explored.
See more coverage from the National Kidney Foundation Spring Clinical meeting.
Herzog C, et al. Trends in Sudden Cardiac Death as a Proportion of Total Cardiovascular Mortality in Prevalent Hemodialysis Patients. Presented at: National Kidney Foundation Spring Clinical Meetings. April 18-22, 2017. Orlando. Poster 176.