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Selection of valve-replacement procedure






The goals of intervention in aortic stenosis are to relieve symptoms, enhance exercise capacity and quality of life, and prolong life expectancy. Indirect physiological benefits include improvement in left ventricular function and regression of left ventricular hypertrophy. Aortic-valve replacement should be considered, regardless of the patient's age at presentation, if overall life expectancy is greater than 1 year and there is a likelihood of survival of more than 25% with improved symptoms at 2 years after the procedure.

The determination of procedural risk and the correct choice of intervention for an individual patient require a multifactorial approach, including assessments of coexisting coronary artery disease, other valve lesions, and noncardiac conditions; frailty; results of invasive and noninvasive anatomical testing; and overall life expectancy. These assessments are best performed by a multidisciplinary group of clinicians, including valve experts, imaging specialists, interventional cardiologists, cardiac surgeons and anesthetists, and physicians with experience in the care and assessment of the elderly. Such a group, termed a “heart team, ” can develop an individualized risk–benefit analysis of the available options for aortic-valve replacement. Patients and their families should also be involved in a shared decision-making process that reflects the preferences and values of the patient.

Surgical aortic-valve replacement remains the standard approach, except in the case of inoperable conditions and procedures with a high estimated surgical mortality. Overall 30-day surgical mortality is less than 3% for isolated aortic-valve replacement and approximately 4.5% for aortic-valve replacement with coronary-artery bypass grafting. After recovery from successful aortic-valve replacement, the rate of overall survival is similar to that among age-matched adults without aortic stenosis.

The primary consideration in the choice of valve type is the risk of reoperation when a bioprosthetic valve is used versus the risk associated with warfarin anticoagulation when a mechanical valve is used. Mechanical valves are appropriate for patients younger than 60 years of age who have no contraindication to anticoagulation, because of the long-term durability of these prostheses. An exception is women of childbearing age, in whom a bioprosthetic valve is preferred, given the risks of anticoagulation and thromboembolism during pregnancy. In patients older than 70 years of age, bioprostheses are favored because valve durability increases with age and the risks of anticoagulation are avoided. In patients between 60 and 70 years of age, the choice of valve is based on patients' preferences and values after a shared discussion between the patient and the surgeon.

Transcatheter aortic-valve replacement (TAVR) is recommended in patients with symptomatic severe aortic stenosis who have a prohibitive surgical risk, which is defined as a predicted risk of death or major complication with surgery of more than 50% at 1 year, a medical condition involving three other major organ systems that is not likely to be improved postoperatively, or a severe impediment to surgery, such as a heavily calcified, fragile (“porcelain”) aorta. In a prospective, randomized clinical trial, TAVR provided a reduction in 2-year all-cause mortality from 68% without TAVR to 43.4% with TAVR, as well as improved symptomatic status and quality of life.

TAVR is also a reasonable alternative to surgical aortic-valve replacement in patients with symptomatic severe aortic stenosis who are at high risk but are suitable candidates for surgery. Randomized studies have shown that the clinical outcomes in such patients are similar with surgical aortic-valve replacement and TAVR, with 1-year rates of death of 26.8% and 24.2%, respectively, with equivalence maintained at 3-year follow-up. The Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score can be used to estimate the risk of death within 30 days after surgery, but other measurements also affect procedural risk. High risk is currently defined as an STS-PROM score of more than 8%, moderate-to-severe frailty, irreversible disease of more than two other organ systems, or possible impediments to a surgical approach.

In randomized trials, several types of complications occurred more frequently during the 30-day postoperative period among patients undergoing TAVR than among those undergoing surgical aortic-valve replacement. These complications included stroke (with rates of 4.9 to 5.5% with TAVR vs. 2.4 to 6.2% with surgery), major vascular complications (5.9 to 11% with TAVR vs. 1.7 to 3.2% with surgery), moderate-to-severe paravalvular aortic regurgitation (10.0 to 12.2% with TAVR vs. 0.9 to 1.3% with surgery), and the need for new pacemaker implantation (3.8 to 19.8% with TAVR vs. 3.6 to 7.1% with surgery). There is evidence that the adverse-event rates associated with TAVR are decreasing. The threshold for choosing TAVR versus surgical aortic-valve replacement is likely to shift as technological developments and increasing clinical experience lead to reductions in complication rates, particularly residual paravalvular leak, which may be associated with an adverse long-term outcome.

Balloon aortic-valve dilation provides only limited hemodynamic benefit, which is offset by the substantial risk of procedural complications and a high probability of recurrent stenosis within 6 months. Balloon aortic dilation is now restricted to occasional patients presenting with hemodynamic compromise, as a bridge to TAVR or surgery.

A further important function of the multidisciplinary approach to the selection of treatment is the avoidance of expensive, high-risk, and ultimately futile procedures in patients who will derive little symptomatic benefit or improvement in quality of life. Examples include patients with a very limited life expectancy, irreversible left ventricular impairment, severe pulmonary disease, impaired mobility as a result of neurologic or musculoskeletal disease, advanced dementia, or other systemic diseases. Specialist palliative care should be available for these patients.

 

 

Клапанный аортальный стеноз является прогрессирующим заболеванием, в котором конечная стадия характеризуется обструкцией оттока из левого желудочка, в результате неадекватного сердечного выброса, снижением физической нагрузки, сердечной недостаточностью и смертью от сердечно-сосудистых осложнений. Распространенность аортального стеноза составляет всего лишь около 0, 2% среди взрослых в возрасте 50-59 лет, но увеличивается до 9, 8% у восьмидесятилетних, с общей распространенностью 2, 8% среди взрослых старше 75 лет. Хотя смертность не увеличивается, когда стеноз аорты протекает бессимптомно, уровень смертности составляет более 50% в течение 2 лет у пациентов с симптоматическим заболеванием, если замена аортального клапана не выполняется достаточно быстро.

В общей сложности 65000 операций по замене аортального клапана были выполнены в США в 2010 году, в первую очередь из за аортального стеноза; 70% из этих процедур были выполнены у пациентов старше 65 лет, что приводит к высокой стоимости медицинской помощи у этого контингента людей. В настоящее время нет никаких медицинских методов лечения, чтобы предотвратить или замедлить прогрессирование заболевания. Вместо этого, улучшению результатов лечения способствует определение людей, подверженных риску заболевания клапана, точное измерение тяжести стеноза, контроль над любой параллельной болезнью и обеспечение своевременной замены аортального клапана.

 

 






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