Author + information
- Claudio Ronco, MD,
- Mikko Haapio, MD,
- Andrew A. House, MSc, MD* (, )
- Nagesh Anavekar, MD and
- Rinaldo Bellomo, MD
- ↵*Division of Nephrology, London Health Sciences Centre, 339 Windermere Road, London, Ontario N6A 5A5, Canada
We are pleased to see that our recent paper (1) on cardiorenal syndrome (CRS) has captured the attention of many investigators, demonstrating the importance of this subject. We have received several positive comments on the structured classification/definition of the CRS that we have proposed. In their letter, Dr. van der Putten and colleagues raise an important point about the bidirectional nature of chronic heart-kidney interactions and question the wisdom of categorizing these into chronic “cardio-renal” (CRS 2) versus chronic “reno-cardiac” (CRS 4) syndromes. They refer to a report by Bongartz et al. (2), who show that common pathophysiology leads to a chronic state of positive feedback leading to progression of both heart and kidney disease. Indeed, this article is a “must read” for anyone with an interest in this disorder, because it highlights a number of important mechanisms that perpetuate and amplify structural and functional derangement, beyond simple hemodynamics.
We agree with Dr. van der Putten and colleagues that the sequence in which chronic heart-kidney conditions arise might not be of paramount clinical importance, because management strategies need to address interruption of these positive feedback loops where possible. However, we also posit that a categorization scheme serves an important role in terms of designing epidemiological studies, identifying target populations for intervention, developing targeted diagnostic tools, studying the prevention and management of the syndromes, and promoting effective communication and collaboration among researchers and clinicians from differing disciplines. In response to these issues, a consensus conference was recently held in Venice, Italy in September 2008 under the auspices of the Acute Dialysis Quality Initiative (ADQI), bringing together key opinion leaders and experts in the fields of nephrology, critical care, cardiac surgery, cardiology, and epidemiology. At this conference, a consensus definition and classification system for the CRS was reached with the 5 subtypes proposed in our review. The ADQI working group recognized that many patients might populate or move between subtypes during the course of their disease, and indeed it might not always be possible to categorize a patient as CRS type 2 or 4. However, the classification is a work in progress, and feedback from interested groups such as Dr. van der Putten and colleagues will be important for future refinements and iterations.
- American College of Cardiology Foundation