cardiovascular disorders
Overview of Cardiac Valvular Disorders
Treatment of Valvular Disorders
Valvuloplasty or valve replacement Management of a valvular lesion commonly requires only periodic observation, with no active treatment for many years. In general, neither lifestyle measures nor medications alter the natural history of valvular lesions. Intervention is usually indicated only when a moderate or severe valvular lesion causes symptoms or cardiac dysfunction. Because patients may not recognize symptoms due to their slow onset, many clinicians use Stress Testing to help monitor patients. The intervention may involve valvuloplasty (valve repair), or valve replacement, all of which may be done percutaneously or surgically. Valvular disorders are currently subject to intensive research to develop percutaneous valve replacement. In addition, randomized, controlled trials of different valvular interventions are being done. The result for patients is an increasing number of therapeutic options and better evidence on how to choose one. For clinicians, the increase in complexity requires a multidisciplinary heart valve team composed of surgeons, cardiologists, and other specialists to help decide which intervention is best for a given patient. If coronary artery bypass surgery is being done, it is usual to surgically treat (during the same operation) any moderate or severe valve lesions, even if asymptomatic. Prevention is indicated when there is a history of endocarditis and for patients with prosthetic heart valves. Two kinds of cardiac valve prostheses are used: Bioprosthetic (porcine or bovine) Mechanical (manufactured) Both types have similar survival rates and rates of valve thrombosis. Mechanical prostheses have a higher rate of bleeding complications, and bioprostheses are more likely to require re-intervention because they deteriorate more rapidly than mechanical valves. is usually used ( Treatment reference ) in patients who are not contemplating becoming pregnant and who meet one or more of the following criteria: Already taking a vitamin K antagonist (eg, for atrial fibrillation) and adhering well to therapy Under age 50 years (for aortic valve) Under age 65 years (for mitral valve) Abioprosthetic valveis recommended to replace the aortic valve for patients>65 years. For patients aged 50 to 65 years, the recommendations are guides only because patients' preferences may deviate, particularly depending on how they perceive bleeding complications versus need for re-intervention. Anticoagulation is required to prevent thromboembolism. The duration and medication used differ depending on the type of prosthesis. Mechanical valve: Lifelong anticoagulation with a vitamin K antagonist (VKA) is needed as per the international normalized ratio [INR] targets below Bioprosthetic valve: Lifelongaspirinis needed (those at low bleeding risk may have 3 to 6 months anticoagulation with a VKA before changing toaspirin). Transcatheter aortic valve: Lifelongaspirinis needed. Addition of eitherclopidogrelor a VKA (INR target 2.5) may be considered for 3 to 6 months after implantation for patients with increased thrombosis risk. Direct oral anticoagulants (DOAC) are ineffective for the above indications and should not be used. Target INRfor most modern mechanical bileaflet prostheses is 2.5, increasing to 3.0 with any of the following: Atrial fibrillation Left ventricular ejection fraction (LVEF)<35% Mitral or tricuspid position Previous thromboembolism Patients who self-monitor their INR or follow up with dedicated anticoagulation clinics have less variability in their INR and fewer adverse events. If patients have thromboembolism despite an adequate INR, consider adding low-doseaspirin. 35%, > 1 mechanical valve— Treatment reference ). Warfarinis the only appropriate oral anticoagulant for thromboembolism prevention in patients with prosthetic valves. Direct oral anticoagulants are ineffective. Women of childbearing age who require valve replacement and plan to become pregnant must balance the teratogenic risk due towarfarinwhen mechanical valves are used against the risk of accelerated valve deterioration when bioprosthetic valves are used. Teratogenic risks can be reduced by use ofheparininstead ofwarfarinin the first 12 weeks and last 2 weeks of the pregnancy, but management is difficult, complications are increased, and careful discussion is required before surgery. Prosthetic valve follow-up is facilitated by obtaining an early postoperative baseline transthoracic echocardiogram (TTE) and by referring to normal echocardiographic parameters (eg, transvalvular gradients) for the patient's prosthesis type and size. If the postoperative baseline study is satisfactory and there has been no interval clinical change, then mechanical valves do not require routine TTE. Patients with bioprosthetic valves should have a follow-up TTE at 5 and 10 years, and then annually. Patients with transcatheter aortic valve prostheses should have annual TTE as the long-term durability of these prostheses is not yet certain. Thrombus formation on bioprosthetic valves may cause hemodynamic deterioration. Thrombus formation is difficult to diagnose; CT and transesophageal echocardiography (TEE) are often required in addition to TTE. Thrombus formation should be distinguished from other causes of valve stenosis because vitamin K antagonism usually results in relief of obstruction due to thrombus formation. 1.Otto CM, Nishimura RA, Bonow RO, et al: 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.Circulation143(5):e35–e71, 2021. doi: 10.1161/CIR.0000000000000932 