As the name suggests, “cardio,” meaning heart, and “renal,” meaning kidneys, is a specific clinical entity where a decline in the heart’s function leads to a decline in kidney function, or vice versa. Hence, the name cardiorenal syndrome (CRS) actually reflects aharmful interactionbetween these two vital organs.
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To further elaborate, the interaction is two-way. Hence, it’s not just the heart whose decline could drag the kidneys down with it. Kidney disease, both acute, including short-duration or sudden-onset, and chronic, including long-standing or slow-onset, could also cause problems with the heart’s function.
Cardiorenal syndrome may start off in acute scenarios where an event such as aheart attackthat leads to acutecongestive heart failurehurts the kidneys.However, that might not always be the case since long-standing chronic congestive heart failure (CHF) can also lead to a slow yet progressive decline in kidney function. Similarly, patients withchronic kidney disease (CKD)are at higher risk for heart disease.
Based on how this interaction is initiated and develops, the cardiorenal syndrome divides into multiple subgroups, including acute CRS, chronic CRS, acute renocardiac syndrome, chronic renocardiac syndrome, and secondary CRS.However, the details of which are beyond the scope of this article, but we will try to give an overview of the bare essentials that the average person might need to know about patients suffering from cardiorenal syndrome.
The Implications
Risk Factors
How It Develops
Cardiorenal syndrome begins with our body’s attempt to maintain adequate circulation. While these attempts might be beneficial in the short-term, over the long-term, these very changes become maladaptive and lead to the worsening of organ function.
While this is not a comprehensive list, a typical cascade that sets off cardiorenal syndrome evolves from the following reasons:
The detailed physiology of each specific mechanism is beyond the scope of this article. The above steps do not necessarily progress in a linear fashion, but rather in parallel.
The net result of the above compensatory mechanisms is that more and more salt and water start to get retained in the body, making the total volume of body fluid go up. This, among other things, will cause the heart to become enlarged over a period of time, a condition called cardiomegaly.
In principle, when the heart muscle is stretched, cardiac outputshouldincrease, but only works within a certain range. Beyond that, the heart’s output will not increase in spite of increased stretch/size which follows the incessant gain in blood volume.
Hence, the patient is typically left with an enlarged heart, a reduced cardiac output, and too much fluid in the body. Fluid overload will lead to symptoms includingshortness of breath, swelling, or edema.
So how is all this harmful to the kidneys? Well, the above mechanisms also do the following:
All these maladaptive changes come together to essentially reduce the kidneys' blood supply, leading to a decline in function. This is just one of the ways cardiorenal syndrome can develop. The initial trigger can be the kidneys causing excess fluid to build up in the body, causing severe heart problems.
Diagnosis
Clinical suspicion will often lead to a presumptive diagnosis. For example, the American Heart Association indicates that certain tests can help detect cardiorenal syndrome, including fluid assessments in the kidney and heart, an echocardiogram to see abnormal myocardial kinetics, and an ultrasound of the kidneys to reveal dimensions.
Treatment
As mentioned above, the management of cardiorenal syndrome is an active area of research for obvious reasons. Patients with cardiorenal syndrome experience frequent hospitalizations and increased morbidity as well as a high risk of death. Therefore, effective treatment is essential. Here are some options.
Diuretics
You might have heard of the so-called “water pills,” calledloop diuretics. If the patient is sick enough to require hospitalization, injections of intravenous loop diuretics are used. If bolus injections of these medications don’t work, a continuous drip may be required.
However, treatment is not that straightforward. The very prescription of a loop diuretic can sometimes cause the clinician to “overshoot the runway” with fluid removal, and cause the serum creatinine level to go up, causing worse kidney function.This could happen from a drop in blood flow to the kidney. Hence, diuretic dosing needs to strike the right balance between leaving the patient “too dry” vs “too wet.”
Fluid Removal
The efficacy of a loop diuretic depends on the kidneys' function and its ability to remove excess fluid. The kidney can often become the weak link in the chain regardless of the diuretic strength. In this situation, invasive therapies to get fluid out like aquapheresis or evendialysismight be needed. The evidence on these invasive therapies has yielded conflicting results.
Other Medications
There are other medications that are often tried (although again not necessarily standard first line treatment) and these includeinotropes(which increase the heart’s pumping force), renin-angiotensin blockers, and other drugs like tolvaptan.
17 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ronco C, Bellasi A, Di Lullo L.Cardiorenal syndrome: an overview.Adv Chronic Kidney Dis. 2018;25(5):382-390. doi:10.1053/j.ackd.2018.08.004Jankowski J, Floege J, Fliser D, Böhm M, Marx N.Cardiovascular disease in chronic kidney disease: pathophysiological insights and therapeutic options.Circulation. 2021;143(11):1157-1172. doi:10.1161/CIRCULATIONAHA.120.050686Spoelstra-de Man AME, Oudemans-van Straaten HM.Acute kidney injury after cardiac arrest: the role of coronary angiography and temperature management.Crit Care. 2019;23(1):193. Published 2019 May 30. doi:10.1186/s13054-019-2476-8Major RW, Cheng MRI, Grant RA, et al.Cardiovascular disease risk factors in chronic kidney disease: a systematic review and meta-analysis.PLoS One. 2018;13(3):e0192895. doi:10.1371/journal.pone.0192895Rangaswami J, Bhalla V, Blair JEA, et al.Cardiorenal syndrome: classification, pathophysiology, diagnosis, and treatment strategies: a scientific statement from the American Heart Association.Circulation. 2019;139(16). doi: 10.1161/CIR.0000000000000664Centers for Disease Control and Prevention.Heart disease facts.Smith GL, Lichtman JH, Bracken MB, et al.Renal impairment and outcomes in heart failure.J Am Coll Cardiol. 2006;47(10):1987-1996. doi:10.1016/j.jacc.2005.11.084Verbrugge FH, Grieten L, Mullens W.Management of the cardiorenal syndrome in decompensated heart failure.Cardiorenal Medicine. 2014;4(3-4):176-188. doi: 10.1159/000366168Prothasis M, Varma A, Gaidhane S, et al.Prevalence, types, risk factors, and outcomes of cardiorenal syndrome in a rural population of central India: a cross-sectional study.J Family Med Prim Care. 2020;9(8):4127. doi:10.4103/jfmpc.jfmpc_533_20Cleveland Clinic.Enlarged heart (cardiomegaly).Fu MR, Li Y, Conway C, Masone A, Fang J, Lee C.The effects of exercise-based interventions on fluid overload symptoms in patients with heart failure: a systematic review and meta-analysis.Biomedicines. 2022;10(5):1111. doi:10.3390/biomedicines10051111Thind GS, Loehrke M, Wilt JL.Acute cardiorenal syndrome: mechanisms and clinical implications.Cleve Clin J Med. 2018;85(3):231-239. doi:10.3949/ccjm.85a.17019Chitturi C, Novak JE.Diuretics in the management of cardiorenal syndrome.Adv Chronic Kidney Dis. 2018;25(5):425-433. doi:10.1053/j.ackd.2018.08.008Bakris GL, Agarwal R.Creatinine bump following antihypertensive therapy: think before you act.Hypertension. 2018;72(6):1274-1276. doi: 10.1161/HYPERTENSIONAHA.118.12051Javed A, Alvi MJ, Afif J, et al.Is Aquapheresis ready for prime time yet for congestive heart failure? A systemic review of the literature.Ren Replace Ther.2023;9(24).doi:10.1186/s41100-023-00477-0Patschan D, Drubel K, Matyukhin I, Marahrens B, Patschan S, Ritter O.Kidney replacement therapy in cardiorenal syndromes.J Clin Med Res. 2022;14(7):264-272. doi:10.14740/jocmr4676Verma D, Firoz A, Garlapati SKP, et al.Emerging treatments of cardiorenal syndrome: an update on pathophysiology and management.Cureus. 2021;13(8):e17240. doi:10.7759/cureus.17240
17 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ronco C, Bellasi A, Di Lullo L.Cardiorenal syndrome: an overview.Adv Chronic Kidney Dis. 2018;25(5):382-390. doi:10.1053/j.ackd.2018.08.004Jankowski J, Floege J, Fliser D, Böhm M, Marx N.Cardiovascular disease in chronic kidney disease: pathophysiological insights and therapeutic options.Circulation. 2021;143(11):1157-1172. doi:10.1161/CIRCULATIONAHA.120.050686Spoelstra-de Man AME, Oudemans-van Straaten HM.Acute kidney injury after cardiac arrest: the role of coronary angiography and temperature management.Crit Care. 2019;23(1):193. Published 2019 May 30. doi:10.1186/s13054-019-2476-8Major RW, Cheng MRI, Grant RA, et al.Cardiovascular disease risk factors in chronic kidney disease: a systematic review and meta-analysis.PLoS One. 2018;13(3):e0192895. doi:10.1371/journal.pone.0192895Rangaswami J, Bhalla V, Blair JEA, et al.Cardiorenal syndrome: classification, pathophysiology, diagnosis, and treatment strategies: a scientific statement from the American Heart Association.Circulation. 2019;139(16). doi: 10.1161/CIR.0000000000000664Centers for Disease Control and Prevention.Heart disease facts.Smith GL, Lichtman JH, Bracken MB, et al.Renal impairment and outcomes in heart failure.J Am Coll Cardiol. 2006;47(10):1987-1996. doi:10.1016/j.jacc.2005.11.084Verbrugge FH, Grieten L, Mullens W.Management of the cardiorenal syndrome in decompensated heart failure.Cardiorenal Medicine. 2014;4(3-4):176-188. doi: 10.1159/000366168Prothasis M, Varma A, Gaidhane S, et al.Prevalence, types, risk factors, and outcomes of cardiorenal syndrome in a rural population of central India: a cross-sectional study.J Family Med Prim Care. 2020;9(8):4127. doi:10.4103/jfmpc.jfmpc_533_20Cleveland Clinic.Enlarged heart (cardiomegaly).Fu MR, Li Y, Conway C, Masone A, Fang J, Lee C.The effects of exercise-based interventions on fluid overload symptoms in patients with heart failure: a systematic review and meta-analysis.Biomedicines. 2022;10(5):1111. doi:10.3390/biomedicines10051111Thind GS, Loehrke M, Wilt JL.Acute cardiorenal syndrome: mechanisms and clinical implications.Cleve Clin J Med. 2018;85(3):231-239. doi:10.3949/ccjm.85a.17019Chitturi C, Novak JE.Diuretics in the management of cardiorenal syndrome.Adv Chronic Kidney Dis. 2018;25(5):425-433. doi:10.1053/j.ackd.2018.08.008Bakris GL, Agarwal R.Creatinine bump following antihypertensive therapy: think before you act.Hypertension. 2018;72(6):1274-1276. doi: 10.1161/HYPERTENSIONAHA.118.12051Javed A, Alvi MJ, Afif J, et al.Is Aquapheresis ready for prime time yet for congestive heart failure? A systemic review of the literature.Ren Replace Ther.2023;9(24).doi:10.1186/s41100-023-00477-0Patschan D, Drubel K, Matyukhin I, Marahrens B, Patschan S, Ritter O.Kidney replacement therapy in cardiorenal syndromes.J Clin Med Res. 2022;14(7):264-272. doi:10.14740/jocmr4676Verma D, Firoz A, Garlapati SKP, et al.Emerging treatments of cardiorenal syndrome: an update on pathophysiology and management.Cureus. 2021;13(8):e17240. doi:10.7759/cureus.17240
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ronco C, Bellasi A, Di Lullo L.Cardiorenal syndrome: an overview.Adv Chronic Kidney Dis. 2018;25(5):382-390. doi:10.1053/j.ackd.2018.08.004Jankowski J, Floege J, Fliser D, Böhm M, Marx N.Cardiovascular disease in chronic kidney disease: pathophysiological insights and therapeutic options.Circulation. 2021;143(11):1157-1172. doi:10.1161/CIRCULATIONAHA.120.050686Spoelstra-de Man AME, Oudemans-van Straaten HM.Acute kidney injury after cardiac arrest: the role of coronary angiography and temperature management.Crit Care. 2019;23(1):193. Published 2019 May 30. doi:10.1186/s13054-019-2476-8Major RW, Cheng MRI, Grant RA, et al.Cardiovascular disease risk factors in chronic kidney disease: a systematic review and meta-analysis.PLoS One. 2018;13(3):e0192895. doi:10.1371/journal.pone.0192895Rangaswami J, Bhalla V, Blair JEA, et al.Cardiorenal syndrome: classification, pathophysiology, diagnosis, and treatment strategies: a scientific statement from the American Heart Association.Circulation. 2019;139(16). doi: 10.1161/CIR.0000000000000664Centers for Disease Control and Prevention.Heart disease facts.Smith GL, Lichtman JH, Bracken MB, et al.Renal impairment and outcomes in heart failure.J Am Coll Cardiol. 2006;47(10):1987-1996. doi:10.1016/j.jacc.2005.11.084Verbrugge FH, Grieten L, Mullens W.Management of the cardiorenal syndrome in decompensated heart failure.Cardiorenal Medicine. 2014;4(3-4):176-188. doi: 10.1159/000366168Prothasis M, Varma A, Gaidhane S, et al.Prevalence, types, risk factors, and outcomes of cardiorenal syndrome in a rural population of central India: a cross-sectional study.J Family Med Prim Care. 2020;9(8):4127. doi:10.4103/jfmpc.jfmpc_533_20Cleveland Clinic.Enlarged heart (cardiomegaly).Fu MR, Li Y, Conway C, Masone A, Fang J, Lee C.The effects of exercise-based interventions on fluid overload symptoms in patients with heart failure: a systematic review and meta-analysis.Biomedicines. 2022;10(5):1111. doi:10.3390/biomedicines10051111Thind GS, Loehrke M, Wilt JL.Acute cardiorenal syndrome: mechanisms and clinical implications.Cleve Clin J Med. 2018;85(3):231-239. doi:10.3949/ccjm.85a.17019Chitturi C, Novak JE.Diuretics in the management of cardiorenal syndrome.Adv Chronic Kidney Dis. 2018;25(5):425-433. doi:10.1053/j.ackd.2018.08.008Bakris GL, Agarwal R.Creatinine bump following antihypertensive therapy: think before you act.Hypertension. 2018;72(6):1274-1276. doi: 10.1161/HYPERTENSIONAHA.118.12051Javed A, Alvi MJ, Afif J, et al.Is Aquapheresis ready for prime time yet for congestive heart failure? A systemic review of the literature.Ren Replace Ther.2023;9(24).doi:10.1186/s41100-023-00477-0Patschan D, Drubel K, Matyukhin I, Marahrens B, Patschan S, Ritter O.Kidney replacement therapy in cardiorenal syndromes.J Clin Med Res. 2022;14(7):264-272. doi:10.14740/jocmr4676Verma D, Firoz A, Garlapati SKP, et al.Emerging treatments of cardiorenal syndrome: an update on pathophysiology and management.Cureus. 2021;13(8):e17240. doi:10.7759/cureus.17240
Ronco C, Bellasi A, Di Lullo L.Cardiorenal syndrome: an overview.Adv Chronic Kidney Dis. 2018;25(5):382-390. doi:10.1053/j.ackd.2018.08.004
Jankowski J, Floege J, Fliser D, Böhm M, Marx N.Cardiovascular disease in chronic kidney disease: pathophysiological insights and therapeutic options.Circulation. 2021;143(11):1157-1172. doi:10.1161/CIRCULATIONAHA.120.050686
Spoelstra-de Man AME, Oudemans-van Straaten HM.Acute kidney injury after cardiac arrest: the role of coronary angiography and temperature management.Crit Care. 2019;23(1):193. Published 2019 May 30. doi:10.1186/s13054-019-2476-8
Major RW, Cheng MRI, Grant RA, et al.Cardiovascular disease risk factors in chronic kidney disease: a systematic review and meta-analysis.PLoS One. 2018;13(3):e0192895. doi:10.1371/journal.pone.0192895
Rangaswami J, Bhalla V, Blair JEA, et al.Cardiorenal syndrome: classification, pathophysiology, diagnosis, and treatment strategies: a scientific statement from the American Heart Association.Circulation. 2019;139(16). doi: 10.1161/CIR.0000000000000664
Centers for Disease Control and Prevention.Heart disease facts.
Smith GL, Lichtman JH, Bracken MB, et al.Renal impairment and outcomes in heart failure.J Am Coll Cardiol. 2006;47(10):1987-1996. doi:10.1016/j.jacc.2005.11.084
Verbrugge FH, Grieten L, Mullens W.Management of the cardiorenal syndrome in decompensated heart failure.Cardiorenal Medicine. 2014;4(3-4):176-188. doi: 10.1159/000366168
Prothasis M, Varma A, Gaidhane S, et al.Prevalence, types, risk factors, and outcomes of cardiorenal syndrome in a rural population of central India: a cross-sectional study.J Family Med Prim Care. 2020;9(8):4127. doi:10.4103/jfmpc.jfmpc_533_20
Cleveland Clinic.Enlarged heart (cardiomegaly).
Fu MR, Li Y, Conway C, Masone A, Fang J, Lee C.The effects of exercise-based interventions on fluid overload symptoms in patients with heart failure: a systematic review and meta-analysis.Biomedicines. 2022;10(5):1111. doi:10.3390/biomedicines10051111
Thind GS, Loehrke M, Wilt JL.Acute cardiorenal syndrome: mechanisms and clinical implications.Cleve Clin J Med. 2018;85(3):231-239. doi:10.3949/ccjm.85a.17019
Chitturi C, Novak JE.Diuretics in the management of cardiorenal syndrome.Adv Chronic Kidney Dis. 2018;25(5):425-433. doi:10.1053/j.ackd.2018.08.008
Bakris GL, Agarwal R.Creatinine bump following antihypertensive therapy: think before you act.Hypertension. 2018;72(6):1274-1276. doi: 10.1161/HYPERTENSIONAHA.118.12051
Javed A, Alvi MJ, Afif J, et al.Is Aquapheresis ready for prime time yet for congestive heart failure? A systemic review of the literature.Ren Replace Ther.2023;9(24).doi:10.1186/s41100-023-00477-0
Patschan D, Drubel K, Matyukhin I, Marahrens B, Patschan S, Ritter O.Kidney replacement therapy in cardiorenal syndromes.J Clin Med Res. 2022;14(7):264-272. doi:10.14740/jocmr4676
Verma D, Firoz A, Garlapati SKP, et al.Emerging treatments of cardiorenal syndrome: an update on pathophysiology and management.Cureus. 2021;13(8):e17240. doi:10.7759/cureus.17240
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