The heart valve stent is a prosthetic heart implant that is used to support and preserve the heart valve in its natural shape and function. The heart valve stent may be made from metal or polypropylene, a bioprosthetic material that mimics those of the natural heart structure. In a study presented in 2005 by "The Annals of Thoracic Surgery," it was noted that within 10 years after a successful heart prosthesis implantation, at least 50 to 60 percent of patients experienced prosthesis-associated problems with results ranging from reoperation to sometimes even death.
Thrombus Formation and Need for Lifetime Anti-coagulant Therapy
A thrombus, or blood clot formation, is one of the most common problems associated with heart valve stents, especially with those made from metal. However, this problem can also happen in rare cases in patients who received bioprosthetic heart valve stents, according to a case study released in 2009 in the online publication "Circulation" by the American Heart Association. The risk factors associated with the formation of thrombus include a lack of anti-blood coagulation medications, such as aspirin or clopidogrel, for the postoperative treatment of the patient and possible coagulation disorders that may predispose a patient to thrombus formation on the valve stent. Open-heart surgery is usually the management of choice for patients that present with this kind of problem. Lifelong anti-coagulant therapy is a must to prevent the development of this complication.
Infection
According to a cardiovascular update released in February 1998 by the American Academy of Family Physicians in their online journal "American Family Physician," a heart prosthesis such as the heart valve stent is a high risk factor in the development of bacterial endocarditis, a relatively rare yet life-threatening infection of the heart. This usually occurs in individuals who develop bacteremia, or bacteria in the blood. Bacteremia may occur spontaneously or as a consequence of other focal infections such as oral infections, urinary tract infection and even pneumonia. Antibiotic prophylaxis before a surgical or dental procedure is usually done in patients with high risk factors, such as heart valve stent, to prevent the occurrence of this problem.
Tissue Calcification
Structural dysfunction secondary to calcification, or the formation of calcium deposits, usually happen in bioprosthesic stents within 15 years following successful implantation, according to "The Annals of Thoracic Surgery" study. This is usually noted in younger-age group of patients, the children and the adolescents, though the exact mechanism is still unknown. Calcification disrupts the normal function of the heart valves causing regurgitation, or leaking back, of the blood within the heart.
References
- "The Annals of Thoracic Surgery"; Calcification of Tissue Heart Valve Substitutes: Progress Toward Understanding and Prevention; Schoen, F.J. et al.; 2005
- "Circulation"; Thrombotic Restenosis After Minimally Invasive Implantation of Aortic Valve Stent; Trepels, T. et al.; 2009
- "Americal Family Physician"; Preventing Bacterial Endocarditis: American Heart Association Guidelines; Taubert, K.A. et al.; February 1998
