Researchers find that kidney dysfunction can be used as a criterion to stratify patients requiring implantable defibrillators.

Summary: A study led by researchers from Fujita Health University, Japan, investigated the role of kidney function as a predictor for sudden cardiac death in patients with congestive heart failure. Published in ESC Heart Failure, the study found that kidney function, measured by the estimated glomerular filtration rate (eGFR), is a significant independent predictor of sudden cardiac death, particularly within the first few months after hospital discharge. The findings suggest the need to reconsider current ICD implantation guidelines to include kidney function as a factor for better predicting and preventing sudden cardiac death.

Key Takeaways:

  1. Kidney Function as a Predictor: The study identified that kidney function, measured by eGFR, is a predictor of sudden cardiac death in patients with congestive heart failure, alongside the already established left ventricular ejection fraction (LVEF).
  2. Importance of Early Post-Discharge Period: The predictive power of kidney function is strongest in the first few months after hospital discharge, with approximately 23% of sudden cardiac deaths occurring within this period.
  3. Reevaluation of ICD Guidelines: Researchers say the findings highlight the need to refine ICD implantation guidelines to include kidney function, which could improve the prevention of sudden cardiac death and reduce unnecessary ICD implantations in patients with heart failure.

Patients with congestive heart failure having a compromised blood supply are at greater risk of sudden cardiac death. With an estimated incidence as high as 22% among these patients, current clinical guidelines recommend using implantable cardioverter defibrillators (ICDs) to help mitigate the risk of sudden cardiac death.

Although the application of ICDs in patients with congestive heart failure is backed by substantial evidence, these studies did not include people with chronic kidney disease, who are an important clinical population. In other words, it is unclear whether the use of ICDs is justified in patients with chronic kidney disease, especially with mild and moderate presentations, given the inherent risk involved in installing these devices.

To address this knowledge gap, researchers led by associate professor Yoshihiro Sobue from Fujita Health University, Japan, investigated to what extent kidney function can be a good predictor for the risk of sudden cardiac death. This study was published in ESC Heart Failure.

Investigating Risk Factors

“The objective of our study was to prospectively investigate the risk factors for sudden cardiac death in a cohort of over 1,500 patients hospitalized with congestive heart failure classified based on the left ventricular ejection fraction (LVEF) and the New York Heart Association functional class, as well as the potential role of kidney function as a determinant of [sudden cardiac death],” says Sobue in a release.

Adding further on the importance of using renal dysfunction for sudden cardiac death, he says, “The determination of renal dysfunction as an independent risk factor of [sudden cardiac death] is important because patients with moderate-to-severe renal dysfunction were excluded in the studies on which current ICD implantation guidelines are based.”

Investigating Risk Factors

The study included 1,676 patients who had visited Fujita Health University Hospital for decompensated heart failure. During the follow-up period, 198 of these patients suffered from sudden cardiac death. Among these events, 23% occurred within three months of discharge.

On conducting statistical analyses of the gathered data, the research team identified two key independent predictors for the risk of sudden cardiac death following discharge. The first was LVEF, which is already considered in the current guidelines. The second was the estimated glomerular filtration rate, which is a measure of how well the kidneys can filter blood.

By adding glomerular filtration rate as a predictor alongside LVEF, regression models could predict sudden cardiac death more accurately. However, as the researchers noted, the predictive power of kidney function in this way diminished over time, being more effective in the first few months after discharge. Coincidentally, roughly a quarter of all cases of sudden cardiac death occurred within three months of discharge.

Implications for ICD Guidelines

In summary, the findings of this study underline the importance of considering additional factors, such as kidney condition, when weighing the benefits of using ICD in a patient. “Refining the criteria for ICD implantation holds the potential for significantly improving the prevention of [sudden cardiac death] and reducing the incidence of complications arising from unnecessary ICD implantations. Hopefully, applying an enhanced stratification methodology involving eGFR may yield better clinical outcomes,” says Sobue in a release.

In the long term, these findings may lead to the revision of guidelines for the use of ICDs and improve the outcomes for patients with congestive heart failure, both with and without chronic kidney disease.

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