Complications

Heart Failure. Hypertension precedes heart failure in 75 - 90% of heart failure cases. High blood pressure has various effects that cause the heart to fail, including:

• To compensate for increased blood pressure, the heart must work harder to pump blood, and so its muscles thicken (hypertrophy), usually on the left side (left-ventricle dysfunction). These thickened muscles pump inefficiently, and, over time, the force of their contractions weakens. The heart muscles then have difficulty relaxing and filling the heart with blood. The heart begins to fail.

Click the icon to see an image of a hypertensive heart.

• The failing heart then triggers a number of hormonal and neurochemical mechanisms to correct imbalances in blood pressure and flow. This response, called remodeling, is helpful in the short run but very destructive and irreversible over time.
• As part of the remodeling process, the heart muscle cells elongate. The muscular walls of the heart dilate and become thinner and inefficient. The cells themselves undergo molecular changes that result in calcium loss, a mineral crucial for healthy heart contractions.
• The end-result of remodeling is a falling volume of blood pumped to the kidneys; the kidneys retain water and salt in response, increasing fluid buildup in the body.
• To make matters worse, the body's arteries narrow in response to a lower blood volume. This constriction forces the heart to work even harder to pump blood through these narrowed vessels, increasing blood pressure and continuing the cycle.

Kidney Disease

Diabetes and Nephropathy (Kidney Disease). High blood pressure is strongly associated with diabetic nephropathy. Patients with type 2 diabetes who show early signs of nephropathy already have hypertension. When patients with type 1 diabetes are diagnosed with early nephropathy, on the other hand, they usually have normal blood pressure readings in the doctor's office. A 2002 study using home monitors, however, found that patients with type 1 diabetes often have high systolic blood pressure during sleep-- before development of nephropathy. Home blood pressure monitoring, then, may help identify patients who are at risk for kidney damage due to high systolic pressure.

End-Stage Kidney Disease. High blood pressure causes 30% of all cases of end-stage kidney disease (medically referred to as end-stage renal disease, or ESRD). Only diabetes leads to more cases of kidney failure. Although anti-hypertensive therapy has reduced the incidence of stroke and heart attack, the incidence in ESRD has almost doubled in the last decade.