Etiology and pathogenesis The susceptibility factors for aortic root infective endocarditis are: 1. Cardiac structural abnormalities. The most common local cardiac structural abnormality is congenital aortic valve diastasis. Other cardiac abnormalities are also seen in degenerative calcific aortic stenosis, connective tissue disease aortic valve closure insufficiency, and rheumatic heart valve disease. The above abnormalities of the heart structure lead to jet blood flow in the heart chambers, resulting in endocardial injury. 2, Previous aortic valve prosthetic valve replacement. The incidence of infective endocarditis after aortic valve prosthetic valve replacement is 0.2-1.4/100 patients a year, about 1.4%; it occurs within 1 year after surgery. Infection of the suture margin is often seen in prosthetic mechanical valves; infection of biological valves can occur in the leaflet or suture margin, and homograft and autologous pulmonary valve infections occur at the same sites as their own aortic valves. 3, bacteraemia, tooth extraction, scaling, oral rinsing and other oral surgery, various interventional procedures, intravenous drug injections, etc. are common causes of bacteraemia, and bacteria colonize the injured endocardium, eventually leading to infective endocarditis. Infective endocarditis can result in destruction of the aortic valve leaflets and can extend to the aortic annulus and surrounding tissue to form an aortic root abscess. The abscess may also break into the pericardial or cardiac cavity. Structural destruction of the aortic root and rupture under the action of intra-aortic blood flow and blood pressure can result in an aortic root pseudoaneurysm. Infective endocarditis of the aortic root can also cause infective embolism of the coronary and body circulation arteries. Patients often develop cerebral infarction, cerebral hemorrhage, and infective aneurysm, infarction, and abscess formation in the liver, spleen, kidney, limbs, and other organs. In addition to the pain and pressure symptoms common to pseudoaneurysms, patients also have the common symptoms of endocarditis: 1. low fever and discomfort: patients often mistake it for a “cold” and take oral antibiotics for a week or so to relieve the symptoms. 2, the appearance of heart murmur or the nature of the original heart murmur changes, patients may appear aortic valve insufficiency and heart failure. 3.The spleen is enlarged. 4.Patients with longer duration of disease may develop pestle-like finger and toe sign. 5.Skin and mucous membrane changes: skin petechiae, fundus hemorrhage, linear hemorrhage under finger and toe nails, painful subcutaneous nodules (Osler nodules) at the ends of fingers and toes. 6. Embolic symptoms caused by large bulky organisms: myocardial infarction, stroke, embolism of other organs such as liver and spleen. Diagnosis In addition to determining the size, location, extent, and growth rate of the pseudoaneurysm, it is important to determine the cause of the disease as an infectious cause. Blood cultures help to determine the type of causative organism and to select antibiotics. Echocardiography helps in the diagnosis of infective endocarditis. Transesophageal echocardiography has a higher diagnostic accuracy than transthoracic echocardiography. Echocardiography can detect endocardial bulges as small as 1-2 mm, but the diagnostic accuracy is lower for infective endocarditis after mechanical valve replacement because of the effect of acoustic shadowing. Echocardiography has confirmatory value for perivalvular abscesses and perivalvular leaks. Treatment Patients diagnosed with infective endocarditis should begin empiric antibiotic therapy immediately after blood is drawn for blood bacterial cultures. Patients with a recent history of urologic and colonic surgery should be treated with antibiotics effective against Gram-negative bacteria; patients with a history of oral surgery should be treated with antibiotics effective against anaerobic bacteria; and those with intravenous drug occultation should be treated with antibiotics effective against Staphylococcus aureus and Staphylococcus epidermidis. After the blood bacterial culture clarifies the pathogenic bacterial species and sensitive antibiotics, antibiotic therapy should be adjusted promptly. Surgery should be performed as soon as possible after the diagnosis of infected aortic root pseudoaneurysm is confirmed, usually after 5 days of effective antibiotics. If the patient develops cerebrovascular complications that significantly increase the risk of surgery, a CT or MRI of the head should be performed to clarify whether the stroke is ischemic or hemorrhagic, and if possible, aortic root surgery is usually performed 2 weeks after an ischemic stroke and 4 weeks after a hemorrhagic stroke. The procedure is usually performed under extracorporeal circulation with femoral artery-femoral vein or femoral artery-right atrium cannulation, with aortic root dissection after ascending aortic block and direct coronary artery cannulation to instill cardiac arrest fluid for myocardial protection. The pseudoaneurysm and infected tissue of the aortic root, including the aortic leaflets, annulus, prosthetic valves, and even the aortic-mitral fibrous junction, mitral valve, left atrial apex, ventricular septum, and right atrial wall, are completely removed. Defects arising from the above mentioned parts should be repaired with autologous pericardium or other artificial materials, aortic root replacement with a valved conduit, and coronary artery bypass surgery should be performed in patients with combined coronary artery embolism. In recent years, aortic root replacement using homogeneous aortic valved conduits has been available, which can repair defects at the aortic valve-micuspid fibrous junction site using homogeneous aortic valve-micuspid fibrous junction. Patients with sepsis may bleed intraoperatively and postoperatively due to impaired coagulation mechanism, and fibrinogen, coagulation factor complex, platelets or fresh plasma can be given; patients with atrioventricular block should be treated with pacemakers; postoperative patients should be alert to the occurrence of multi-organ failure, cerebrovascular complications, and metastatic abscesses of other organs, and should be given timely treatment.