Aortic Valve Stenosis is the narrowing or obstruction of the heart 's aortic valve. The aorta is a large artery that originates in the left ventricle (lower chamber) of the heart. The narrowing and obstruction of the aortic valve prevents it from opening properly and blocks the flow of blood from the left ventricle to the aorta and onward towards the rest of the body. Aortic valve stenosis occurs in approximately 5 out of every 10,000 people.1 It occurs more commonly in males than females. Symptoms do not often appear until middle age or older. Aortic valve stenosis is characterized by the left ventricular pressure being much greater that the aortic pressure during left ventricular ejection. The pressure gradient across the stenotic lesion results from both increased resistance (related to narrowing of the valve) and turbulence distal to the valve. The magnitude of the pressure changes is determined by the severity of the stenosis and the flow rate across the valve. Severe aortic stenosis results in reduced ventricular stroke volume due to increased afterload, increased end-systolic volume, and a compensatory increase in end-diastolic volume and pressure. Aortic valve stenosis is associated with a mid-systolic murmur because of turbulence that occurs as blood moves across the stenotic valve.5 Aortic valve stenosis of any cause can be a serious condition because it can weaken the heart. If the aortic valve is narrowed, the left ventricle has to work harder to pump a sufficient amount of blood into the aorta and onward to the rest of the body. In response, the left ventricle may thicken and enlarge. At first, these adaptations help the left ventricle pump blood with more force, but eventually these changes weaken the left ventricle and ultimately the heart overall. The most common cause of aortic valve stenosis in patients 65 or older is called "senile calcific aortic stenosis", or otherwise known as calcification, which
References: 1. Medlineplus. Medical Encyclopedia. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/00178.htm. Accessed April 27, 2004. 2. Medicine.Net. Aortic Valve Stenosis. Available at: http://www.medicinenet.com/aortic_stenosis/article.htm. Accessed 1996-2006. 3. MayoClinic.com. Heart Disease. Available at: http://www.mayoclinic.com/health.aortic_valve_stenosis/DS00418. Accessed September 23, 2005. 4. Penn. State. Milton S. Hershey Medical Center, College of Medicine. Available at: http://www.hmc.psu.edu/heartinfo/conoaorticvalve.htm. Accessed January 18, 2006. 5. WebMD. Health Topics. Available at: http://www.webmd.com/hw.heart_disease/hw179876.asp. Accessed April 18, 2006. 6. American Heart Association. Learn to Live. Available at: http://www.americanheart.org/presenter.jhtml?identifier=11068. Accessed April 18, 2006. 7. Istephanous, George MD. The patient with aortic valve stenosis. International anesthesiology clinics. Fall 2005; volume 43: 21-31.