Why is coronary blood flow so important

These vessels act as a backup to the coronary arteries, so if the coronary arteries narrow and limit blood flow to the heart, the collateral vessels may enlarge and start working to pick up the slack. This collateral circulation allows blood to flow around a blocked arter y to other arteries or to the same artery after the blockage, which helps protect the heart from the injury that can occur when blood flow is limited. Because the heart needs oxygen to function properly , the coronary arteries play a vital part in heart health.

If they are diseased or damaged, they can reduce blood to the heart, which can lead to heart attack. Atherosclerosis is a buildup of plaque on the walls of the coronary arteries, which narrows and weakens the arteries, making it difficult for the heart to do its job.

Atherosclerosis is a leading cause of coronary artery disease CAD. Coronary artery disease is a leading cause of death. Coronary artery disease may be treated by several medical specialists, including cardiologists, cardiothoracic surgeons, cardiovascular surgeons, interventional cardiologists and cardiac surgeons. Beaumont is a world leader in heart innovation.

Beaumont Hospital, Royal Oak has been ranked as one of the top cardiac and heart surgery programs in the nation for more than two decades. Also, oxygen-depleted blood must be carried away. The coronary arteries wrap around the outside of the heart. Small branches dive into the heart muscle to bring it blood. Left main coronary artery LMCA. The left main coronary artery supplies blood to the left side of the heart muscle the left ventricle and left atrium.

The left main coronary divides into branches:. The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart. The circumflex artery branches off the left coronary artery and encircles the heart muscle. Exercise training also alters local control of coronary resistance vessels.

Thus arterioles exhibit increased myogenic tone, likely due to a calcium-dependent protein kinase C signaling-mediated alteration in voltage-gated calcium channel activity in response to stretch.

Conversely, training augments endothelium-dependent vasodilation throughout the coronary microcirculation. This enhanced responsiveness appears to result principally from an increased expression of nitric oxide NO synthase. Finally, physical conditioning decreases extravascular compressive forces at rest and at comparable levels of exercise, mainly because of a decrease in heart rate.

Impedance to coronary inflow due to an epicardial coronary artery stenosis results in marked redistribution of myocardial blood flow during exercise away from the subendocardium towards the subepicardium. However, in contrast to the traditional view that myocardial ischemia causes maximal microvascular dilation, more recent studies have shown that the coronary microvessels retain some degree of vasodilator reserve during exercise-induced ischemia and remain responsive to vasoconstrictor stimuli.

These observations have required reassessment of the principal sites of resistance to blood flow in the microcirculation. A significant fraction of resistance is located in small arteries that are outside the metabolic control of the myocardium but are sensitive to shear and nitrovasodilators. The coronary collateral system embodies a dynamic network of interarterial vessels that can undergo both long- and short-term adjustments that can modulate blood flow to the dependent myocardium.