Answer:
Pulse pressure is the difference between systolic blood pressure (SBP) and diastolic blood pressure (PAD), and is an index of arterial compliance. The 24-hour clinical and ambulatory pulse pressure (PP), and the pulse wave morphology, estimate the elasticity of the large arteries.
The rules prior to 1993 defined the severity of hypertension only in terms of diastolic pressure. Actuarial tables, which are used by insurance companies to estimate the risk of death, are also based on diastolic pressure although they recognize the importance of systolic pressure and pulse pressure as predictors of death. For years, an acceptable level of systolic pressure was taught was determined by adding 100 mmHg to the patient's age. Until the early nineties (1990), permanence without demonstrating the value of treating elevated systolic pressure in patients with diastolic pressure less than 90 mmHg.
Only during the last ten years, systolic blood pressure and pulse pressure have been recognized as accurate diagnostic predictors of cardiovascular events, especially in the elderly. This change has occurred as a result of a greater appreciation of the research data.
There is evidence that pulse pressure is positively associated with a variety of cardiovascular diseases. Pulse pressure has been shown to be an important predictor of cardiovascular events and death, above and beyond the predictive power of mean blood pressure. Epidemiological studies have shown that cardiovascular mortality is positively related to the value of SBP. However, with any SBP value, cardiovascular mortality is higher when the PAD is lower. Hypertensive patients with a pulse pressure above 65 mmHg, more commonly present with a hypertrophy of the left ventricle or a diastolic dysfunction on echocardiographic examination.
Clinical and outpatient PP are associated with age and higher levels of systolic BP, and ambulatory PP, in addition, with female sex. The high-risk hypertensive population (diabetics and cardiovascular disease) has a higher PP than the rest of the hypertensive.
When hypertension develops, early changes in circulation tend to primarily affect systemic vascular resistance at the level of smaller vessels. In younger people, the increase in vascular resistance is reflected by an increase in systolic and diastolic pressure. Over time, the relative contribution of increased vascular resistance to high blood pressure decreases, and the role of stiffness of the great vessels increases.
When the great vessels age, the elastic elements in their walls break and over the years they degrade with repeated stress. At the same time non-elastic elements such as collagen tend to accumulate. The large vessels become less elastic and greater initial pressure is necessary to accommodate the volume of blood thrown by the heart into the ventricular ejection. The result is increased systolic pressure that promotes cardiac hypertrophy.
