Cardiovascular Disaster in Hemodialysis patients Pattaraporn MD.

Causes of death in prevalent dialysis patients 2008-2010 41.6% 26.5%

Cardiovascular Disaster

Sudden death Unexpected natural death Within a short time period >> 1-24 h Due to cardiac etiology New or more serious symptoms

Possible Mechanisms Responsible for SD in HD Rapid electrolyte shifts/Hypervolemia Myocardial interstitial fibrosis Microvessel disease CHF CAD/MI LVH/LV dysfunction QT dispersion Cardiac arrhythmia cardiomyopathy Cardiac arrest Inflammation Ischecmic heart disease Sympathetic overactivity

Left ventricular Hypertrophy and Heart failure Concentric LV hypertrophy Eccentric LV hypertrophy

Left ventricular Hypertrophy and Heart failure LVH is an powerful indicator of mortality in dialysis patients Presence of LVH >>> arrhythmia Left ventricular systolic dysfunction >> arrhythmia Redaelli B: Lancet 1988;ii:305–309.

Myocardial Interstitial fibrosis and Microvessel disease Inadequate capillary density + increased oxygen demand >> relative hypoxia >> fibrosis

Myocardial Interstitial fibrosis and Microvessel disease Fibrous tissue >> high electrical resistance Development of atrial and ventricular reentry types of arrhythmias Risk factor for the development of arrhythmias especially during the dialysis

QT Dispersion Difference between the longest and shortest QT intervals >> EKG 12 lead Predict an increased risk of malignant arrhythmias Normal value of QT dispersion in normal subjects was ≤40 ms Dialysis patients with QT dispersion > 74 ms >>  ventricular arrhythmias or SD Low K+ and low Ca2+ >> acquired long QT syndrome

Sympathetic overactivity  Heart rate >> myocardial demand  supply >> cardiac hypertrophy and fibrosis Decrease heart rate variability (reflecting autonomic dysfunction) >> increased risk for all-cause and SD in HD

Inflammation Marker : C-reactive protein, inhibit the hepatic generation of albumin Reflection of vascular injury VS actually promotes vascular injury ? High CRP level ( >6 mg/l ) : independent , predictive marker of future myocardial infarction Herzig, K. A. et al. J. Am. Soc. Nephrol. 12, 814–821 (2001). Inflammation could trigger SD >> atherosclerosis or direct effect on myocardium

Other factors Rapid electrolyte shifts Hypervolemia Anemia Dyslipidemia Hypertension Calcium/phosphate deposition

Prevention of Sudden Death Avoiding low K dialysate & rapid electrolyte shifts Prevention of Sudden Death ACEI and ARBs Beta-blocker Implantable defibrillators

Beta-blocker Reduction of Improve Heart rate variability Cardiac hypertrophy & fibrosis Antifibrillary activity Ventricular arrhythmia Reduced risk of acute MI Improve Heart rate variability Increase in baroreflex sensitivity

ACEI and ARBs Reduction of Cardiac hypertrophy & fibrosis Fatal arrhythmia

Avoiding low K dialysate & rapid electrolyte shifts: To avoid QT dispersion Re‐entrant arrhythmias Premature ventricular extrasystole (VES)

Most effective therapy for SCD in the general population Indication Implantable defibrillators or Implantable Cardioverter Defibrillators (ICDs) Most effective therapy for SCD in the general population Indication Survival of cardiac arrest due to VT or VF Episode of sustained VT causing severe hemodynamic compromise Episode of sustained VT without hemodynamic compromise + EF 35% MI + EF 35% + nonsustained VT on 24-h ECG + inducible VT on electrophysiologic testing MI + EF 30% QRS duration  120 ms on ECG

Greater risk of device complications Implantable defibrillators or Implantable Cardioverter Defibrillators (ICDs) 42% risk reduction for death in dialysis patients with ICDs implanted according to conventional guidelines Greater risk of device complications No statistically increase >>> infection or fistula thrombosis Kidney Int. 2005;68:818-825.

Herzog CA et al. Kidney Int. 2005;68:818-825.

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