Vascular resistance is defined by the physical resistance of a capillary, vein, or artery to flowing blood. Vascular disease can affect the entire organism but also a single organ such as the heart or brain. In any case, initial warning signs must be heeded in order to be able to counteract a serious course of the disease, which can also be fatal.
What is vascular resistance?
Vascular resistance is defined by the physical resistance of a capillary, vein, or artery to flowing blood. In individual vessel segments, vascular resistance is not identical but varies. Dynamic control is provided by the circulatory system. If the definition of resistance refers to a single organ, a distinction is made between coronary, pulmonary, and cerebral vascular resistance.
Function and task
Coronary vascular resistance consists of a vasal and extravascular component. The vasal provides most of the physical regulation of a coronary blood flow. The extravascular is based on mechanical stress exerted by myocardial contraction and relaxation. Pulmonary vascular resistance (PVR) refers to resistance in the pulmonary circulation. This begins in the pulmonary artery and extends into the atrium of the left heart. It is not accessible to clinical measurement, so pulmonary capillary occlusion pressure is used as an approximation to determine pulmonary resistance. It is also referred to as the wedge pressure (PAP). In addition, pulmonary vascular resistance is divided into acute pulmonary hypertension and chronic pulmonary hypertension. Cerebral vascular resistance is the flow resistance that cerebral vessels impose on blood flow and is driven by systemic blood pressure. In this way, blood flow to the brain is regulated.
Diseases and disorders
Significant diseases related to vascular resistance include:
Coronary artery disease (CAD):
It results from inadequate blood flow to the heart muscle, which fails to ensure oxygen and nutrient requirements. The cause is often arteriosclerosis in the coronary arteries. Coronary heart disease includes angina, myocardial infarction and sudden cardiac death. Plaques are to blame. These are fatty deposits that block all or part of the blood flow. Pulmonary vascular disease:
This usually refers to pulmonary embolism (pulmonary embolism). Responsible for this disease is the blockage of a pulmonary artery by blood clots. It is usually preceded by a leg vein thrombosis. Primary pulmonary hypertension:
Its incidence is about 1,1,000,000, which is why this condition is one of the very rare ones. Also, the exact cause is not yet known. Secondary pulmonary hypertension:
It usually occurs as a result of another underlying disease. In order to protect the lungs, this underlying disease must therefore be treated as a priority. This is the only way to control and regulate pulmonary hypertension. Acute pulmonary hypertension:
In this case, the pulmonary vessels are affected by constriction. This often exists only temporarily in the early stages. For example, during exertion. The radius of the vessels is reduced by the contraction of the vascular musculature, which leads to an increase in blood pressure. Chronic pulmonary hypertension:
In this case, remodeling of the pulmonary vessels can be diagnosed. The vascular musculature increases in circumference before slowly remodeling into connective tissue. The pulmonary vessels are subsequently less flexible and cannot regain their flexibility. If sclerosis is added, the condition of the affected person visibly worsens. The lungs are no longer properly ventilated, resulting in an increasing lack of oxygen in the lungs over time. Another consequence of this clinical picture is the continuous reduction in cardiac output. Cerebral vascular disease:
Apoplexy (stroke) as a sudden event ranks among the 3 most frequent causes of death. The cause is thrombosis in 40-50% of cases, embolism in 30-35% and cerebral hemorrhage in 20-25% of cases, triggered by blood leaking from a cerebral artery. High blood pressure and reduced blood clotting capacity are the most common causes of cerebral hemorrhage. This also applies to intracerebral venous congestion.For example, sinus vein thrombosis. Vascular diseases of the brain and spinal cord:
In the brain and spinal cord, it is not uncommon for aneurysms to occur. These are the result of pathological changes in the arteries (arterial walls). These are located on the surface of the brain or spinal cord. The size of an aneurysm can range from a few millimeters to 50 millimeters in diameter. Triggers include not only arteriosclerotic changes in the aneurysm wall. A disturbed blood flow or blood pressure are also possible. In addition, genetic or inflammatory vascular lesions or vascular changes may be the cause. Symptoms include extremely severe headache, which may be accompanied by nausea and vomiting. The following complaints can be observed in pulmonary hypertension.
observed:
The vast majority of affected individuals experience dyspnea (breathlessness, shortness of breath). A poorer general condition, circulatory disturbances up to syncope (circulatory collapse) and angina pectoris (chest tightness) occur in almost every second patient. Symptoms such as fatigue and the formation of edema (swelling) are also common. In contrast, cyanosis (blue-violet coloration of fingertips, lips, or skin) and Raynaud’s syndrome (temporary circulatory disturbances) occur less frequently.