Problems with Prosthetic Heart Valves
Despite the care given to heart valve design and patient welfare, problems may arise. Some complications of heart valve surgery are described here along with how to recognize them as well as treat and prevent them. These problems do not occur in most patients, but awareness of them can increase the likelihood of success with your new heart valve.
Prosthetic heart valve failure – Failures of prosthetic heart valves have been reported. Replacement of valves at an advanced age carries a high probability of mortality (death): 11.5% less than 70 years of age, 17.3% greater than 70 years of age and 32.0% at greater than 80 years of age.53,54 For tissue valves, failure is usually a slow, progressive deterioration of valve function ending in the need to replace the prosthesis. This usually occurs from five (5) to 15 years after implant.8 Many patients fear reoperation due to the risk of death and the pain or recovery at an advanced age.
“Something that’s very rarely talked about in the literature is all the patients who have structural valve deterioration and are either too old or too sick to be considered for reoperation.”
–Dr. Eric G. Butchart, University Hospital of Wales, Cardiff,
quoted in “Thoracic Surgery News”, the official newspaper of the American Association for Thoracic Surgery. January/February 2006, page 17.
Mechanical valves fail much less frequently. Any sudden change in your health requires medical attention. Although mechanical valve failure is rare, it is extremely important to identify and correct it immediately. Do not hesitate to contact your physician immediately and receive treatment as fast as possible if anything unexpected should occur. WITH YOUR AWARENESS AND YOUR PHYSICIAN’S CARE, THE HAZARDS OF THESE PROBLEMS CAN BE MINIMIZED.
Reoperation of pig or cow tissue valve due to tissue failure – This will occur if you live longer than the life of your tissue valve. The preserved tissue of the valve will last a limited number of years, 5-15 years for most patients, potentially less for younger patients.8 Reoperation requires the chest cavity to be reopened. Certain risks accompany reoperation that were not present for the first operation. Tissue may be scarred together and cause excess hemorrhage in certain cases. Operation time is usually extended. Recurrence of pain from the operative site and the inconvenience and risks of recovery must be endured again. Replacement of valves at an advanced age carries a higher probability of mortality (death) (Table 6).
Table 6. Reoperative Mortality (Death)
|60-70 years||>70 years||>80 years|
Reoperation risk increases with increasing age.53,54
Pannus (scar tissue) ingrowth – The body will produce fibrous scar tissue or pannus where the native valve has been removed and a heart valve prosthesis is implanted. It is common to both tissue and mechanical devices and often leads to thrombosis of the valve requiring reoperation.9-13 The On-X heart valve is the only mechanical heart valve with leaflet guards to add protection from pannus ingrowth. In the company’s twelve-year implant history as of the year 2008, pannus ingrowth has not been reported.
Stuck leaflets (impingement) – Leaflets in mechanical heart valves can become trapped by pressure on the valve orifice.14Tissue from underneath the valve in the mitral position or pannus tissue can cause leaflets to stick. This has been reported in professional literature for other mechanical heart valves, but has not been reported post-operatively with the On-X valve in more than 70,000 patients in 12 years.9-14
Figure 7. About anticoagulant medication and INR.
About Anticoagulant Medication and INR
What is “blood thinner” and why do I have to take it?
“Blood thinner” is a commonly used and misleading name substituted for “anticoagulant medication”. This medication interrupts the blood clotting mechanism and is required when the possibility of blood clot formation exists-it does not “thin” the blood. Blood clots can be stationary (thrombosis) or they can travel in the bloodstream (embolism) and lodge in a vital organ or artery and block blood flow. The most common reasons for using anticoagulants are 1) arrythmias (irregular heartbeats) and 2) an artificial substance is introduced into the blood stream such as an artificial heart valve, dialysis graft, left heart assist device, etc.15 International Normalized Ratio (INR) is a measurement of the level of anticoagulant medication activity in the blood. An INR of 1.0 (one) is normal for people not taking anticoagulant medication. For patients with mechanical heart valves, an INR of 2-3.5 is recommended.15 The generic name for this medicine is warfarin sodium and the most common brand name is Coumadin®.16 Warfarin sodium has been used for more than forty years and is safe and effective when taken as directed.
What is a platelet inhibitor?
The most commonly used platelet inhibitor is aspirin, but there are several others. These drugs decrease the ability of platelets to initiate the clotting sequence.
Can I test my blood at home for “blood thinner” effectiveness?
If you are prescribed anticoagulant medication, home monitoring of INR level has been shown to reduce postoperative complications by as much a 50%.17 Your insurance coverage may pay for lease of the monitor and the test cartridges. Medicare coverage is available three months after surgery. You can purchase these materials with a prescription if your insurance does not pay for them. A good web site to check out these devices/tests is www.hometestmed.com for Quality Assured Services (QAS), the leading supplier of home testing devices and monitoring. On-X Life Technologies Inc. and QAS have formed an alliance called On-X Valve INR Care to help patients receive training and supplies needed for home monitoring of INR level.
On-X Valves + On-X Valve INR Care = FEWER COMPLICATIONS FROM VALVE SURGERY!
For further information about On-X Valve INR Care, please call (800) 504-3916 or (888) 339-8000.
Anticoagulant-related bleeding (hemorrhage) – With all mechanical heart valves and many tissue heart valves, your physician will prescribe an anticoagulant medication (Figure 7) and platelet inhibiting drugs for you to take continually after surgery. Anticoagulant medication is commonly referred to as “blood thinner”, but it does not really thin the blood. It interferes with the clotting sequence and increases the amount of time to form a clot. This gives time for any damaged blood cells to be washed away from the implanted valve and less likelihood of clot formation.
In some instances, patients may suffer from unexpected bleeding due to these medications. Some signs to watch for are: cloudy urine, black bowel movements, general weakness and unusual pains in the abdomen. It is extremely important when taking an anticoagulant that you have your blood monitored closely, that you work closely with your physician to be sure you are taking the drug in the right amount and that you take this drug at the same time every day without fail. If you think you have the symptoms described above, contact your physician immediately. It is highly recommended that you carry identification noting that you are taking an anticoagulant. Identification cards and bracelets are available from several sources, including the MedicAlert Foundation, 2323 Colorado Avenue, Turlock, California 95382, 1(888) 633-4298, www.medicalert.org.
Thrombotic complication – With any valve including tissue heart valves, it is possible that blood could clot on the valve. Such a blood clot (thrombus) could grow large enough to affect the proper function of the valve (valve thrombosis) or could break loose (embolize) and travel with the blood to another part of the body and then block blood flow to that area (thromboembolism). After surgery, if you notice a return of some of the same problems you had before surgery (shortness of breath), or if you experience any unusual dizziness, blurred vision, loss of hearing, numbness or weakness, contact your physician immediately. The occurrence of bleeding and thrombotic complications reflect the delicate balance required in taking your anticoagulants. Close cooperation with your physician in controlling your medicine can minimize the occurrence of both these complications. Regular, routine blood tests will be required to assure that your anticoagulant prescription is correct. Proper diet will prevent any unwanted effects on anticoagulant medication. You may opt to test your blood at home as is discussed in Figure 7.
Prosthetic heart valve infection – Any foreign body placed inside the body is subject to the possibility of becoming infected. While this does not occur often with prosthetic heart valves, certain precautions should be taken to reduce risk. Any fever that you experience should be reported to your physician. Any prolonged incident (more than two or three days) of sinusitis or upper respiratory symptoms such as a cold or flu should be reported to your physician. Remind him/her that you have a prosthetic heart valve. He/she may conduct tests to rule out prosthetic heart valve infection. You can minimize the chance of infection occurring by keeping all your physicians informed that you have a heart valve prosthesis implanted. Especially inform your dentist, because any dental procedure carries the risk of infecting your prosthesis. Your dentist will prescribe an important antibiotic treatment prior to your dental appointments to help avoid infection. Inform physicians performing any other invasive procedure such as surgery, colonoscopy, gastroscopy, angiography, heart catheterization, etc., about your implanted valve. Be careful with any skin abrasion or wound that could lead to an infection, such as cuts and blisters, and keep your physician informed of any suspicious events.
Hemolytic anemia (hemolysis) – In rare circumstances, cases of anemia have been reported with heart valve replacement.18-21 This occurs when too many red blood cells are damaged and broken down by contact with, or flow through, an artificial valve (tissue or mechanical). Red blood cell breakdown leads to a reduction in oxygen-carrying hemoglobin, which can cause listlessness, weakness, or fatigue. Your physician is aware of this possibility and can provide treatment when necessary. This is not the same process as bleeding or hemorrhage caused by anticoagulant medication.
Complications not related to the implanted heart valve – There is a wide range of problems that may be associated with heart surgery but not the valve specifically. These are also infrequent and include: arrhythmia (irregular heart beat), fluid in the lungs (pleural effusion) or heart cavity (pericardial effusion), inflammation of the lining of the lung cavity (pleuritis), infection/inflammation in the lungs (pneumonia), breastbone (sternum/sternal) wound infection, infection of the heart cavity (pericarditis), heart failure due to non-valvular causes such as blocked heart arteries and others. Again, if you have any change of health including symptoms such as chest pain, dizziness, persistent cough, fever, sore throat/infection, sinus infection, ear pain/infection and others, please contact your cardiologist and/or surgeon and discuss these conditions with them.