Kidney and the Heart
The following are some of the effects on the kidney which may be induced by cardiovascular diseases.
1- Heart failure, affects the kidney through the backward and the forward failure effects.
A- systemic venous congestion This results in an increase in the capillary pressure, transudation into interstitial spaces with decrease in effective circulating volume. This will be aggravated by the presence of forward failure and decrease in perfusion of the vital organs including the kidney. The result is oliguria; and in severe cases it may lead to prerenal failure. Increase in right atrial pressure and systemic congestion will increase secretion of ANP.
B- Decreased cardiac output. This results in a decrease in the renal perfusion with:
• Renal vasoconstriction
• Increased secretion of renin, angiotensin, aldosterone with consequent salt and water retention.
• Increased secretion of ADH with consequent water retention.
2- Infective endocarditis: This may result in glomerulonephritis, embolic renal disease and renal impairment.
3- Cardiogenic shock: This may result in either pre-renal failure or acute tubular necrosis; according to the severity and the duration of the condition.
4- Atrial fibrillation may lead to thromboembolic disease involving the kidney.
5- Hypertension may result in nephrosclerosis.
6- Dissecting aortic aneurysm may extend to affect the renal vessels with consequent ischaemic renal disease.