Last Updated on May 8, 2023
Introduction: What is Total Peripheral Resistance?
Peripheral vascular resistance (total peripheral resistance or systemic vascular resistance) refers to the resistance to blood flowing through the arteries and arterioles in the peripheral circulation. It is an important physiological phenomenon that plays a vital role in maintaining blood pressure and blood flow to all organs and tissues. Peripheral vascular resistance can result from many factors, such as hypertension and congestive heart failure. Understanding the mechanism of peripheral vascular resistance and its clinical significance is crucial in the management of cardiovascular diseases.
Prime Revival Research is conducting hypertension research studies, investigating potential treatment options to manage peripheral resistance caused by hypertension.
What are the Three Factors that Influence Peripheral Vascular Resistance?
Peripheral vascular resistance can change. It is dependent on several factors but the 3 most important ones are:
- Diameter of the blood vessels
- The viscosity of the blood
- Length of the vessels
These factors are subject to change and can be affected by different physiological phenomena, including inflammation, changes in vascular tone, and fluctuation in hormones.
What is Total Peripheral Resistance?
According to an article published on the JAMA Network, total peripheral resistance is the force of blood measured from the root of the aorta to the venous exit in the auricles of the heart. In other words, it is the force of the blood when it exits the heart subtracted from the force at which it enters back.
The Role of Peripheral Resistance in Maintaining Blood Pressure
The resistance by the peripheral vessels is important in maintaining blood pressure. It does this by preventing excessive blood flow to the peripheral tissues. A rise in blood pressure causes the vessels to constrict. It increases resistance and reduces flow to the tissues. This process helps prevent organ damage from hypertension.
The Effects of Abnormal Peripheral Resistance
Various cardiovascular diseases can result from abnormalities in peripheral vascular resistance. An increase in resistance can directly increase blood pressure (hypertension), damaging the heart, kidneys, eyes, brain, and other organs. Conversely, a decrease in resistance can result in organ damage, for example, through shock.
Mechanism of Peripheral Resistance
Peripheral vascular resistance happens through multiple mechanisms. It may involve one or several mechanisms all at once. These may include contraction and relaxation of the arterial smooth muscles, the release of vasoactive substances by the inner lining cells (epithelium), the production of neurotransmitters and hormones, and, lastly, the activation of the autonomic nervous system (including the renin-angiotensin-aldosterone system).
Vascular smooth muscle cells are important in controlling blood vessel width by adapting to diverse stimuli such as neurotransmitters and hormones. The endothelium lining the inner surface of the arteries produces vasoactive chemicals (like nitric oxide), which help in altering the vascular tone.
Norepinephrine, epinephrine, and angiotensin II also play a vital part in regulating peripheral vascular resistance by stimulating the contraction of vascular smooth muscle cells. Additionally, the autonomic nervous system directly affects the diameter of blood vessels by constricting the vascular smooth muscles.
The renin-angiotensin-aldosterone system (RAAS) usually maintains blood pressure and, thus, peripheral resistance through fluid balance. Angiotensin II (produced by the activation of the renin-angiotensin-aldosterone system) can contract the vascular smooth muscle cells, again causing a rise in peripheral vascular resistance.
Causes of Peripheral Resistance
- Congestive heart failure: In certain conditions, such as congestive heart failure (CHF), there is an increase in peripheral vascular resistance.
- Shock: In contrast to CHF, there is a decrease in vascular resistance in shock, thus decreasing organ perfusion.
- Hypertension: In multiple cardiovascular diseases, peripheral vascular resistance alters. Hypertension is one of the most widely known examples of this phenomenon. It is when the systolic blood pressure rises over 140 mmHg, or the diastolic blood pressure is over 90 mmHg. Peripheral resistance rises as the blood vessels begin constricting.
- Raynaud’s disease: In Raynaud’s disease, the blood supply to the extremities is affected by episodic vasospasms. These vasospasms cause a decrease in the oxygen supply resulting in numbness and cold. It usually causes symptoms in the fingers, toes, and other extremities.
- Diabetes: Diabetes, a common metabolic illness, is linked to an increased risk of cardiovascular disease. It does this by impacting the peripheral resistance. Diabetes increases blood vessel resistance leading to hypertension and other cardiovascular issues.
Treatment for Peripheral Vascular Resistance
Lifestyle modifications such as losing excess weight and regular exercise can help. Dietary changes are also important in reducing the risk of cardiovascular disease. Calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin receptor blockers are the first-line medications to manage peripheral resistance caused by hypertension.
Surgical procedures involve angioplasty and bypass surgery that can treat peripheral artery blockage by increasing blood flow and decreasing resistance in afflicted vessels.
Peripheral vascular resistance is a physiological process maintaining blood pressure within the arteries. Abnormalities like hypertension or diabetes can cause changes in peripheral resistance leading to various cardiovascular disorders. Lifestyle modifications, medications, or certain surgical procedures can prevent these conditions.
Prime Revival Research Institute is facilitating cardiology clinical research through its clinical trials to develop more effective hypertension treatments targeting peripheral resistance. Maintaining healthy peripheral vascular resistance is essential to maintaining overall cardiovascular health and preventing cardiovascular diseases.