Relation of heart and kidney

God has created human body as a perfect machine in which every organ has its vital role and all the organs are interlinked. They run and control the human body as a team. If any organ is affected it will directly or indirectly cause stress to all other organs and weaken the perfectly managed organ system, there by ultimately weaken the body. The relationship of heart and kidney is like skin and nail which cannot be separated.

Heart and Kidney are interlinked so closely that, any effect in kidney or heart cause adverse effect on each other. If kidney is healthy your heart will be healthy and vice- versa. Appreciating this we had celebrated world kidney day as “protect your kidney save your heart” slogan in 2011.

These two organs have enormous role in controlling our blood pressure. More than 90 percent of hypertension or increase in blood pressure is related to the cause of kidney and its surrounding organs and structure. The high blood pressure will directly affect heart and kidney.

Heart & Kidney Diseases

The diseases of heart and kidney cause the syndrome know as cardio-renal syndrome (CRS) (cardio means heart and renal mean kidney). It can be describe in few points as follows-

CRS-1: Acute heart problem causing acute kidney injury:

In this case, the person has no previous heart or kidney problem but sudden malfunctioning of heart causes sudden kidney failure which can be recovered. Like myocardial infraction causing acute kidney injury (sudden heart attack causing sudden failure of kidney)

CRS -2: Long term heart diseases causing long term kidney disease:

In this case, the person has long term heart disease which causes slow deterioration of renal function which can be partially recovered. Like chronic heart failure causing chronic kidney disease (long term heart disease like reduction of pumping action of heart causing slowing decreasing renal function)

CRS 3: Acute kidney injury causing acute heart problem:

In this case, the person has no renal and heart problem but suddenly failure of kidney causes sudden problem in heart. Like acute kidney injury causing pulmonary edema, arrhythmias (sudden failure of kidney causes increase in fluid level causing heart failure and fluid in the lung causing severe breathlessness or increase in potassium level causing abnormal beating of heart)

CRS 4: Chronic kidney disease causing long term cardiac disease:

In this case, the person who is having chronic kidney disease develops chronic cardiac issue like: uremic cardiomyopathy, left ventricular hypertrophy, chronic heart failure (long term kidney disease causes weakness of cardiac muscles (cardiomyopathy), increase structure of cardiac muscles which needs to withstand high blood pressure (hypertrophy) and increase risk of heart attack)

CRS 5: Simultaneously involvement of heart and kidney due to long term effect of hypertension, diabetes mellitus or in acute condition like sepsis ( some disease will simultaneously affect heart and kidney like long term uncontrolled blood pressure, uncontrolled blood sugar level or in case of severe infection causing kidney and heart failure like in sepsis)

Apart from these causes other cause which affect heart and kidney are-

Contrast induced nephropathy post-angiography: in this case, the persons who are at risk (old age , diabetes mellitus, dehydration, previously known kidney disease ) have unwanted damage to some structures in kidney due to dye used in angiography, which can be prevented and treated by different measures.
Cholesterol emboli: in some cardiac intervention procedures like angiography some piece of fat moves in blood circulation and lodge in different organs including kidney and cause its damage.
Patient on hemodialysis: the issue which are seen in patient on long term hemodialysis (mostly due to inadequate hemodialysis) are pulmonary hypertension (increase blood pressure in pulmonary artery), uremic cardiomyopathy (reduce contraction ability of heart), left ventricular hypertrophy (increase mass of cardiac muscle), pericardial effusion (fluid around heart), arrhythmia (disturbance in rhythm of heart).
Patient after renal transplantation: cardiovascular disease is the most common cause of death in patients after renal transplant in 1 year time in developed country. However, in developing countries infections are the most common cause. So, the renal transplant patient should regularly check their cardiovascular status to remain healthy.

If kidney disease and heart disease exists simultaneously then the management becomes very challenging. The treatment can be two way swords and which is only possible by fluid balance.

Adequate cardiac contraction and adequate kidney perfusion is the ultimate goal which is to be achieved to tackle this issue. Moreover, renal replacement therapy in the form of dialysis and renal transplant is difficult but not impossible in this kind of patients in whom we should be more vigilant and extra care is needed.