Clinical Pearls & Morning Reports
Paravalvular leaks have been reported to occur in approximately 7 to 17% of patients after surgical mitral-valve replacement and in approximately 2 to 10% of patients after surgical aortic-valve replacement. Read the NEJM Case Records of the Massachusetts General Hospital here.
Q: What are some of the causes of hemolytic anemia related to a prosthetic heart valve?
A: In patients with a prosthetic heart valve, hemolysis can occur as a result of high shear stress with turbulent flow and can be precipitated by new foreign material, such as a loose suture, abnormal flow characteristics of the prosthetic valve (more common with a ball-and-cage valve), valve failure or degeneration, or a paravalvular leak. Paravalvular leaks are the most common cause of hemolytic anemia among patients with a prosthetic valve. Paravalvular leaks result from the development of a space between the exterior sewing ring of a prosthetic heart valve and the native cardiac tissue, through which there is regurgitant flow.
Q: What are some of the risk factors for paravalvular leak?
A: Annular calcification, endocarditis, previous chest radiation, and inflammatory diseases have all been identified as risk factors for the development of paravalvular leaks after surgical valve replacement.
A: Most paravalvular leaks are subclinical. However, in approximately 5% of patients in whom a paravalvular leak develops after surgical heart-valve replacement, severe heart failure, hemolytic anemia, or a combination of the two will occur. Symptoms are more likely to occur in patients with mitral paravalvular leaks than in patients with aortic paravalvular leaks. Symptomatic heart failure tends to occur when large paravalvular leaks with clinically significant regurgitation are present, whereas hemolytic anemia can occur with paravalvular leaks of any size. Mitral paravalvular leaks that occur through a relatively small orifice have been reported to be associated with larger pressure gradients between the left ventricle and left atrium, harsher heart murmurs, and more severe hemolysis than leaks occurring through larger orifices.
A: Hemolytic anemia has been reported to resolve spontaneously in approximately 75% of patients with aortic paravalvular leaks, as compared with less than 15% of patients with mitral paravalvular leaks. Asymptomatic patients usually do not require intervention. Intervention is indicated in patients with symptoms of heart failure or refractory hemolytic anemia. Treatment of symptomatic paravalvular leaks can include medical therapy, surgical repair of the paravalvular leak, or closure of the paravalvular leak with the use of a transcatheter device. The procedural success rates of transcatheter paravalvular leak closure have been reported to be between 73% and 84%. The success of transcatheter paravalvular leak closure is highly dependent on the size and location of the paravalvular leak, as well as the number of leaks.