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The human heart is an organ of immense importance. Regulating blood flow through the heart is a complex process that involves four heart valves – the mitral valve, tricuspid valve, pulmonary valve and aortic valve. When one or more of these heart valves become diseased or damaged, it can significantly impact heart function and health. In such cases, prosthetic or artificial heart valves are implanted through surgery to replace the damaged valves. Let’s take a deeper look at prosthetic heart valves – what they are, the types available and their importance in cardiac health.
Types of Prosthetic Heart Valves
There are two main types of prosthetic heart valves available – mechanical heart valves and biological/tissue heart valves.
Mechanical Heart Valves
Made entirely from non-biological materials like metals and polymers, mechanical heart valves last the longest among all prosthetic valves. The two most common types are:
1. Bileaflet valves: Composed of two semicircular leaflets that open and close smoothly with each heartbeat to regulate blood flow. Made from medical-grade metals or pyrolytic carbon.
2. Tilting disc valves: Contain a circular disc that tilts back and forth to open and close the valve orifice. Made from medical-grade metals.
Mechanical valves are highly durable but require patients to take blood thinners for life to prevent blood clots from forming on the synthetic surfaces.
Biological/Tissue Heart Valves
Also known as bioprosthetic heart valves, they are constructed from biologically sourced tissues like pig/cow heart valves or the patient’s own pulmonary valve.
1. Porcine (pig) heart valves: Created from harvested pig heart valves chemically treated for compatibility with the human body. Durable but may have to be replaced every 10-15 years.
2. Bovine (cow) pericardial valves: Made from the fibrous sac surrounding the cow heart. Thinner and more flexible than porcine valves.
3. Pulmonary autograft (Ross procedure): Uses the patient’s pulmonary valve to replace the malfunctioning aortic valve, with their own pulmonary artery used to fashion a new pulmonary valve.
Biological valves have material resembling natural human tissue but their lifespan is limited. They don’t require life-long blood thinners like mechanical valves.
Emergency vs. Elective Replacements
Valve replacements can either be emergency procedures during acute situations or elective surgeries for chronic valve issues.
Emergency Replacements: In cases of severe valve infections, major damage from a heart attack, or certain congenital defects, surgery may be urgently needed to save the patient’s life or prevent further damage. Temporary prosthetic valves are sometimes implanted during emergency situations until a permanent valve replacement can be scheduled later.
Elective Replacements: For rheumatic heart disease, age-related valve deterioration, or mild-moderate congenital defects, doctors will closely monitor the patient and perform valve replacement surgery once the risks of not operating outweigh the risks of the procedure itself. This allows for more planning and pre-surgical testing.
Surgical Procedure for Implantation
All prosthetic valve implantation surgeries are performed under general anesthesia, with surgeons making an incision in the chest or upper abdomen depending on the valve being replaced.
For aortic valve replacement, the incision is made between the ribs providing access to the aorta. The damaged native aortic valve is then removed and the prosthetic valve carefully sewn into place using stitches.
Mitral valve replacement involves an incision in the wall of the heart (left atriotomy) to access the mitral valve from inside the left atrium. For tricuspid valve replacements, the incision reaches into the right atrium.
Once secured, the prosthetic valve is tested for any leaks under simulated heartbeat conditions before closing the incision sites. Patients are then monitored in an Intensive Care Unit for several days following surgery.
Outcomes and Long-Term Monitoring
With the latest valve designs and surgical techniques, success rates for prosthetic heart valve replacement surgeries exceed 95%. However, long-term follow up by cardiac specialists is vital.
Mechanical valve patients require consistent blood thinner monitoring and blood tests. Their lifestyles may be restricted due to higher bleeding risks from traumatic injuries.
Biological valve recipients need periodic echocardiograms to check valve function and integrity, as replacements may be needed 10-20 years later depending on age and other factors at implantation.
Regularcheckups with a cardiologist allow early detection of any valve-related complications and adjustments to medical therapy as needed over the patient’s lifetime. With proper care, prosthetic heart valves can restore heart function and provide decades of active living following implantation.
Prosthetic heart valves have revolutionized the treatment of heart valve disease by replacing life-threatening malfunctions with mechanical or biological substitutes. As valve designs and surgical approaches continue advancing, more and more patients are receiving a new lease on life thanks to these life-saving medical devices. With close cardiologist follow-up, heart valve recipients can look forward to years of improved quality of life.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
