CVD and progression of CKD share many risk factors, and the relevant interventions target both of these conditions. Hypertension is both a cause and consequence of kidney disease
High blood pressure is the second leading cause of chronic kidney disease (CKD), first being diabetes. High blood pressure or hypertension is also the main cause of Cardio Vascular Disease (heart failure, ischemic heart disease, etc). Narrow, stiff or clogged blood vessels (due to high cholesterol, etc) or excess fluid with blood results in high blood pressure. Whether cardio vascular disease (CVD) impacts Chronic Kidney Disease (CKD) or vice versa is a matter of medical research, the relationship between the two is explained below:
High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys. If the kidneys’ blood vessels are damaged, they may stop removing wastes and extra fluid from the body. Extra fluid in the blood vessels may then raise blood pressure even more, creating a dangerous cycle.
On the other hand, Cardiovascular disease (CVD) begins early in the course of Chronic Kidney Disease (CKD). Damaged kidneys can’t produce enough of the hormone EPO to create an adequate number of red blood cells. The heart tries to compensate for this lack by pumping harder. Over time, the heart muscle becomes larger but weaker and starts to pump inefficiently. A damaged heart can no longer pump sufficient amounts of blood to the body’s tissues. Also, when the kidneys receive low blood flow, they act as if the low flow is due to dehydration. So they respond by releasing hormones that stimulate the body to retain sodium and water. Blood vessels fill with additional fluid, and blood pressure goes up. Edema (fluid waste) begins to back up into the lungs, and it becomes difficult to breathe.
Blood pressure range of 120/80 mm Hg to 140/90 mm/Hg should be targeted for CKD patients. The first number is called the systolic pressure and represents the pressure as the heart beats and pushes blood through the blood vessels. The second number is called the diastolic pressure and represents the pressure as blood vessels relax between heartbeats.
The prevalence of CVD increases with worsening kidney function: close to 50% of individuals with creatinine clearances <50 mL/min, and close to 75% of patients starting dialysis are reported as having left ventricular hypertrophy (enlargement and thickening (hypertrophy) of the walls of heart’s main pumping chamber (left ventricle)). Among patients starting dialysis, some individuals are reported to have had past myocardial infarction or coronary revascularization.
Cardiovascular risks may arise due to various factors including family history, hyperglycemima (in patients with diabetes), hypertension, physical inactivity, stress, RAS activity, thrombogenetic factors, elevated cholesterol and triglycerides, etc.
WHAT TO DO
- To prevent or slow down kidney disease from high blood pressure, one must opt for healthy eating habits, exercise daily, walk/ swim/ gym without excessive strain (as heart may fail of too much strain is taken), reduce stress by meeting friends, listening to music, singing or playing musical instruments, engaging in social work, etc.
- Obesity results in high cholesterol and high blood pressure so one must seriously attempt to reduce weight to a normal range.
- Smoking actually kills a person suffering from diabetes/ high blood pressure/ chronic kidney disease. To know more, read RAS section.
- Sodium in table salt interferes with Blood Pressure medicines and must be used in very low quantity for hypertensive and/ or CKD patients. Cooked food may be sprayed with powdered rock salt for taste. See diet section for further details. If a CKD patient is given either ACE-I or ARB drugs (both drugs are not given together), a patient may develop hyperkalemia and therefore potassium rich food should be completely removed from diet. Banana, broccoli, spinach, potatoes, peas, cucumber, mushroom, sweet potatoes are rich in potassium. Some light exercise, walking, may also help ease hypertension.
The most important thing is to take the blood pressure medicines as prescribed by the doctor on time and NOT skip medicines as per mere will. It is also important NOT to gulp antacids, pain killers, antibiotics without consulting a doctor.
mm: millimeter; Hg: Mercury