Explain Hypertension in biochemical or physiological risk factors?
The importance of elevated BP as a risk factor for CAD, heart failure, cerebrovascular disease and renal failure in both men and women has been clarified in a large number of epidemiological studies. Hypertension causes structural and functional changes in the vessel wall - as well as in the heart itself. The vessels are narrowed increasing the resistance to flow; endothelial damage promotes atherosclerosis and both atheroma and vasospasm can easily cause complete blockage in those narrowed arteries. Increase in resistance to flow leads to enlargement of the heart (left ventricular by pertrophy), which raises oxygen demand. That in itself increases the risk of CAD. Systolic BP is at least as powerful a coronary risk factor as the diastolic BP and isolated systolic Hypertension is now established as a major hazard for coronary disease and stroke.
Risk is related to the level of blood pressure and increases as the blood pressure rises - there is no definite cut-off point. Hypertension not only promotes atheroma but also increases the oxygen demand of the heart and thereby aggravates ischaemia. Clinical trials of BP lowering using different drugs have clearly shown that the risks associated with increased BP call be substantially reduced, especially for stroke, but also for CAD and heart failure: a goal BP of < 130185 mmHg is appropriate for primary and secondary prevention. The BP goal needs to be even lower in diabetic patients as well as in patients with renal parenchyma disease in whole renal protection may occur at values even less than 80mnlHg.