The Role of Implantable Cardioverter-Defibrillators in Prevention of Sudden Cardiac Arrest in Chronic Kidney Disease

Sudden cardiac arrest (SCA) is defi ned as sudden, unexpected loss of heart function, breathing and consciousness, resulting from an electrical disturbance in the heart stopping its action and blood fl ow, and cardiovascular diseases are the major risk factors for SCA. It has been reported that more than 20% of all deaths in patients with advanced chronic kidney disease is due to arrhythmias and SCA [1].


Letter to the Editor
Sudden cardiac arrest (SCA) is defi ned as sudden, unexpected loss of heart function, breathing and consciousness, resulting from an electrical disturbance in the heart stopping its action and blood fl ow, and cardiovascular diseases are the major risk factors for SCA. It has been reported that more than 20% of all deaths in patients with advanced chronic kidney disease is due to arrhythmias and SCA [1].
SCA is a malignant condition that could happen outof-hospital or in-hospital. A metanalysis published in 2010 evaluating more than 140,000 patients, showed that in patients suffering an out-of-hospital SCA survival to hospital admission was 23.8% and survival to hospital discharge 7.6% [2].
Cooper, et al., analyzed more than 2,000 adult in-hospital cardiopulmonary resuscitation (CPR) attempts in a 1200bed general hospital in UK in order to provide survival rates and associated factors from a 10-year study. Immediate survival rate following CPR was 38.6%, 24.7% at 24 h, 15.9% at discharge, and 11.3% at 12 months. There were very low survival rates for pulse-less electrical activity and asystole compared to ventricular fi brillation, and survival rates were higher in patients aged less than 60 years [3].
Cardiovascular diseases are a frequent complication of renal dysfunction and chronic kidney disease (CKD) and myocardial infarction and stroke have been reported to be risk factors for in-hospital mortality in these patients [4,5].
Mortality of dialysis patients is high, in the fi rst year of hemodialysis, all-cause mortality was reported to be 421 deaths per 1,000 patient years after the second month of treatment, decreasing to 193 after one year of therapy. In the same way cardiovascular mortality was reported to peaked at 163 deaths per 1,000 patient years two months after treatment beginning, then to decrease to 79 after 12 months [6]. SCA is reported to be the most frequent cause of death in 24.3 of incident and 26.5% of prevalent dialysis patients recorded in the United Sates Renal Data System [7]. SCA rate of uremic patients is higher than the rate recorded in subjects with any recognizable cardiac disease and general population (62 vs 5.98 vs 1.89/1,000 patient-year respectively) [8]. and dialysis was an intervention reported in 3% of cases [16].
In 2010, Larkin using data from the same registry analyzed a cohort of more than 49,000 adults, and found that renal insuffi ciency or dialysis was reported in 32.5% of cases and the latter condition was independently associated with in-hospital mortality [17].
Moreover after a SCA surviving patients suffer consequences such as post-cardiac arrest syndrome (PCAS) due to anoxic brain injury, arrest-related myocardial dysfunction, and systemic ischemia/reperfusion response [18]. PCAS could also cause acute renal failure. Yanta et al., analyzed retrospectively 311 adult patients aged 58 years, admitted to an intensive care unit after successful resuscitation from out-of-hospital SCA, and found that 32 (10.3%) developed acute renal failure, of whom 13 (40.6%) were treated by renal replacement therapy, and 27 (8.7%) developed acute kidney injury. Development of renal failure was not associated with survival to hospital discharge [19].
All these data demonstrate that SCA and renal dysfunction are strongly related at every stage of the disease, CKD is a risk factor for SCA and SCA is an important cause of death in these population, suggesting a role for implantable cardioverterdefi brillator (ICD).
On the other hand impact of ICD implantation on survival of patients with renal dysfunction is still a matter of debate, on the other hand data suggest that the benefi t decreases with worsening renal dysfunction [20].
CKD has been reported to be a clinical relevant predictor of mortality in patients undergoing ICD implantation for primary prevention purpose [21]. Sakhuja, et al., conducted a meta-analysis in order to evaluate the effectiveness of ICD therapy in patients receiving dialysis, and found that despite having ICDs, uremic patients had a 2.7-fold higher mortality. Moreover they compared subjects receiving dialysis and those with CKD but not receiving dialysis, and did not fi nd signifi cant difference in mortality [23]. according to CKD stage. They found that subjects with CKD were older, less commonly men, more often white, and more frequently had comorbid illness and that risk of death after ICD placement was proportional to CKD severity. Factors associated with increased risk of death included CKD severity, age >65 years, heart failure symptoms, diabetes mellitus, lung disease, serum sodium <140 mmol/L, atrial fi brillation or fl utter, and a lower ejection fraction. They concluded that in patients with CKD, several factors could infl uence clinical decision making on primary prevention ICD candidacy [28].