Essential hypertension is not just a risk factor for symptomatic disease such as stroke and myocardial infarction. Although never measured the resistance to cardiac output, systemic vascular resistance is elevated. When we realized this we can understand that Essential Hypertension reflects the fact that generalized vascular disease is already present. This is the real problem and elevated blood pressure that indicates that. The rise of blood pressure in to preserve flow is the presence of this elevated resistance is actually a beneficial response. If this did not happen and flow gradually became compromised, the lack of perfusion would be noticed and consequences would develop. It is a good thing that blood pressure rises to overcome the resistance to it. The physical illness that this measurement indicates is the reason for the morbidity and mortality.
Elevated Blood Pressure or BP as in Essential Hypertension is a disease with an ICD 10 code and is valid for diagnosis, treatment and billing. There is a focus on this measurement. The physical illness is a vascular disease that produces an elevated resistance to blood flow. As the total resistance to blood flow increases, most notably with age the autoregulation of blood pressure responds to preserve flow. We we can see and measure the increase in the blood pressure easily and often do. It is essentially impossible to measure or image the progression of vascular disease and the increasing resistance. We don’t see the physical illness but it exists. There is diffuse, widespread vascular disease.
Blood pressure has both positive and negative effects. It supports perfusion and oxygen delivery. On the other hand, blood pressure can be seen to damage the vascular system. The proper balance of the necessary perfusion pressure and possible injury is a difficult task.
Blood pressure generally rises with age. In some people with a predisposition, it rises faster than in other people and leads to Essential Hypertension. If neglected the elevated blood pressure will induce greater vascular disease and accelerate the elevation of blood pressure. One of the best reasons for treating the diffuse vascular disease with medications is to prevent progression with treatment of the present situation. In other words hypertension begets hypertension.
People with blood pressure that runs symptomatically on the low side of normal are fortunate. This is not associated with vascular disease. Sensitivity to for instance, fainting may be associated with blood pressure that tends to be low. Fainting is generally benign, stroke is not. The absence of widespread vascular disease and low resistance to blood flow is a positive thing. Symptomatic acutely low blood pressure that occurs with for instance severe blood loss is another matter. Acute conditions that produce low blood pressure are serious indeed. Aside from bleeding there are other acute conditions such as infection, sepsis and cardiac conditions that may cause blood pressure to be below normal. Chronically low blood pressure is generally benign
The organizations that promote guidelines for blood pressure emergencies are supported financially by the provider not the patients. Guidelines are written to benefit the organizations that write them and their supporters. Is there a way to know what the outcome of blood pressure manipulation is in an emergency such as an ischemic or hemorrhagic stroke? The answer is no but that does not stop the arrogant from asserting their arrogance. The best treatment for hypertension in the presence of an acute event such as a stroke should be formulated by a trained and experienced clinician for the particular situation. The best treatment in this situation is usually no intervention at all and this should always be acceptable. A guideline such as blood pressure reduction by a certain value is not helpful.
The generalized vascular disease that causes essential hypertension is a permanent change to the vascular system. This uncomfortable thought is important. It helps us to realize that although with treatment the measurement, the blood pressure may improve, the illness, the vascular disease is still there. We should consider that the illness is not the blood pressure, it is a vascular disease associated with but not caused by elevated blood pressure. Theoretically, functionally and pathologically high blood pressure is not the problem. It is a reflection of the problem, not the problem itself.
Considering that the illness is a vascular disease we realize that it is not eradicated when medication successfully reduces blood pressure. This idea of a permanent prescription reinforces that this will be a life long problem. The prescription as written is valid for life and can always be used.