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Diastolic heart failure: a confusing concept
1Emeritus Professor of Medicine/Nephrology, Utrecht University, Oude Zutphenseweg 3, 7251HL Vorden, The Netherlands. evert.mees@hetnet.nl
Insights
Fluid congestion is central to heart failure, regardless of left ventricular function. Kidney salt excretion issues, especially with modern diets, may drive fluid retention and heart failure, highlighting the need for further research.
Area of Science:
- Cardiology
- Nephrology
- Internal Medicine
Background:
- Heart failure pathophysiology has evolved, recognizing presentations with preserved or reduced left ventricular function.
- Previous models linked reduced function to hypotension and renal salt/volume retention, and preserved function to diastolic dysfunction and pulmonary congestion.
- The distinction between acute vascular and acute congestive heart failure has also evolved.
Purpose of the Study:
- To argue that fluid congestion is a unifying factor in heart failure presentations.
- To propose that impaired kidney salt excretion, particularly in the context of high salt intake, contributes to fluid retention in heart failure with preserved left ventricular function.
- To emphasize the need for mechanistic research into fluid balance and renal function in acute heart failure.
Main Methods:
- Review and synthesis of observational studies on heart failure pathophysiology.
- Analysis of concepts distinguishing acute vascular versus acute congestive heart failure.
- Extrapolation from end-stage renal disease and dialysis patient data regarding volume control.
Main Results:
- Fluid congestion is identified as a key element across different heart failure presentations.
- In heart failure with preserved left ventricular function, impaired renal salt excretion is hypothesized as a primary driver of fluid retention.
- Strict volume control in end-stage renal disease patients on dialysis demonstrates the potential to prevent heart failure.
Conclusions:
- Fluid congestion is a critical, unifying aspect of heart failure.
- Further systematic research is required to elucidate the precise roles of renal haemodynamics and fluid balance in acute heart failure.
- Understanding these mechanisms could lead to improved prevention and management strategies for heart failure.
Abstract:
Descriptions of the pathophysiology of heart failure have gone through a substantial evolution in the last 50 years. It is now recognised that heart failure can occur in the presence and also in the absence of a reduction in left ventricular function. In the former situation, this classically has been described to lead to hypotension and secondary salt and volume retention by the kidneys, further aggravating cardiac function. In the latter, this has been described to lead to pulmonary congestion because of impaired cardiac diastolic filling. These concepts have further evolved in the discrimination of 'acute vascular' versus 'acute congestive' heart failure. The current paper builds the argument from numerous smaller observational studies that irrespective of the clinical presentation of heart failure, fluid congestion is the key. If left ventricular function is preserved, fluid retention is probably due to the inability of damaged kidneys to excrete the large amounts of salt ingested with modern diet. In the extreme of end-stage renal disease requiring haemodialysis, heart failure is frequent, but can be prevented almost entirely by strict volume control. Unfortunately, the absence of systematic studies describing fluid volumes and renal haemodynamic and reabsorptive function in patients with acute heart failure precludes the final proof of our concept. This paper therefore is a strong call for mechanistic research in this area.