Heart Valve Operation: Patient Follow-Up and Complications
Essentials
Prophylaxis of prosthetic valve thrombosis and thromboembolism consists of careful anticoagulation and patient education. The direct anticoagulants (dabigatran, rivaroxaban, apixaban, edoxaban) should not be used for anticoagulation in patients with a mechanical valve prosthesis.
The aim of follow-up is to detect complications (valve thrombosis, developing of pannus formation preventing valve movement, paravalvular leak, endocarditis, bleeding complications) at an early stage and refer the patient to the correct unit for treatment.
Endocarditis prophylaxis is carried out.
Any underlying diseases (hypertension, congestive heart failure, diabetes) should be treated carefully.
All this should be done in cooperation with specialized care.
General remarks
If the patient has a mechanical valve prosthesis, optimal anticoagulant treatment and its follow-up are the most important tasks in outpatient care to prevent thrombosis and bleeding complications.
Other follow-up in primary health care can normally take place at 1-year intervals if the patient is otherwise healthy and has no major risk factors.
Annually, about 4-8% of heart valve replacement patients have serious complications. About half of these are associated with the underlying disease and are therefore difficult to prevent.
Most problems occur in the first few months after surgery, when the patient is still being followed up by specialized care.
As serious complications often occur between follow-up visits, the importance of contacting the responsible physician/unit if there are changes in the patient's condition should be emphasized to the patient.
Empiric antimicrobial treatment should not be started in a patient with a valve prosthesis and fever, unless the cause of fever is evident.
Patients with a valve prosthesis need endocarditis prophylaxis in association with high-risk procedures.
During monitoring after valve surgery, patients frequently develop atrial fibrillation, often with absent or only mild symptoms. This is an indication for anticoagulant therapy even in cases where it would not have been necessary because of a biological or TAVI valve alone. After implantation of a biological valve prosthesis, direct oral anticoagulants can be used to treat a patient with atrial fibrillation.
The direct anticoagulants (dabigatran, rivaroxaban, apixaban, edoxaban) are not recommended for anticoagulation therapy in patients with a mechanical prosthesis because it was shown in a study that the efficacy of dabigatran was clearly inferior to that of warfarin, and there is no evidence available regarding the other direct anticoagulants in this indication.
The INR is usually set at 2.5-3.5 for patients with a mitral valve prosthesis and at 2.0-3.0 for patients with an aortic valve prosthesis. Depending on the patient's individual risk factors the target level may be set somewhat higher. The target is set at a level at which the combined risk of thromboembolic and severe bleeding complications is lowest. The therapeutic target must be set by a cardiologist / cardiac surgeon.
The target level of anticoagulation should be precise, and the medication must not be reduced or interrupted even temporarily for a common surgical procedure with a low bleeding risk. Surgery with a high risk of bleeding usually requires temporary reduction of anticoagulation (INR target level usually 1.5).
If the INR falls below target level, warfarin therapy should temporarily be complemented with a LMW heparin at a therapeutic dose, at least for patients with a mitral valve prosthesis.
LMW heparin heparin is started immediately if the INR falls below the target range, and it may be discontinued when the INR has been in the target range for 2 days.
Successful anticoagulation therapy is not possible without adequate patient information. The patient must be aware of the defined target level and the rules of management when the target is not achieved.
The patient must be aware of the influence of diet and other medication on the anticoagulation therapy. There should be no great variation in the level of vitamin K intake. Regular vitamin K supplementation may help if INR levels are highly unstable. Good results have been obtained with INR self-monitoring.
More frequent INR monitoring is required in all situations that may affect the balance of anticoagulation therapy (injuries, acute illnesses, changes in other medication etc.).
In some patients with a mitral valve prosthesis and other risk factors for thromboembolism (AF, heart failure, another valve prosthesis), warfarin therapy may be supplemented with additional aspirin.
After an acute coronary syndrome and insertion of a stent, anti-platelet drugs are added to the medication for a short period of time, after hospital treatment usually clopidogrel, only.
In such cases, the INR should be monitored more frequently, and it should be ensured that no anaemia emerges. A gastroprotective drug should usually be included in the treatment.
In association with INR monitoring, basic blood count with platelet count should be checked from time to time (about 2 or 3 times a year) in order to detect occult bleeding.
Pregnancy presents many problems and challenges to both the mother with a valve prosthesis and the foetus. A cardiologist should evaluate the risks before conception. Whenever possible, valve replacement should be scheduled for after pregnancy. Warfarin is teratogenic and is replaced by heparin at least during the first trimester and also before delivery to avoid bleeding complications. In Europe, the recommendations concerning the two latter trimesters are not as strict as they are in the United States.
For instructions on warfarin therapy in scheduled surgery and procedures, see Warfarin Therapy.
After the insertion of a biological valve (mitral valve surgery, in particular) or valvuloplasty, warfarin therapy is still often used for a period of 3 months. After this period and depending on risk factors (e.g. predisposition to atrial fibrillation), the medication may be changed to either direct anticoagulants or aspirin at a dose of 100 mg/day.
After a TAVI procedure, aspirin is generally used as long-term therapy, unless there are other reasons for anticoagulation. Patients with atrial fibrillation are given just anticoagulants, either direct oral anticoagulants or warfarin therapy.
After the insertion of a biological valve or valvuloplasty, patients with atrial fibrillation can be given direct anticoagulants.
Thrombosis of the mechanical heart valve prosthesis is the most important postoperative complication of valve replacement surgery; it often rapidly becomes life-threatening, and the diagnosis of the condition should be promptly established.
A mechanical prosthesis is more liable to thrombosis in the mitral or tricuspid position than in the aortic position. The risk also depends on the type of prosthesis and on patient-specific factors, including comorbidities.
Most cases of valve thrombosis are caused by failure of anticoagulant therapy.
Symptoms
Physical decline or sudden collapse
Dyspnoea, syncope, angina pectoris
Local symptoms of arterial thromboembolism, most often cerebrovascular disorders
Symptoms may last from days to weeks.
Clinical findings
Weakened or absent prosthesis clicks
Louder ejection or flow murmur, new regurgitation murmur
Hypotension, narrow pulse-pressure, tachycardia
Dilatation of the heart or signs of heart failure
Heart auscultation findings should be entered in the patient record while the valve prosthesis is functioning normally. This will allow detection of any changes.
Diagnosis
The most essential thing is to keep the possibility of a valvular complication in mind!
Echocardiography (transoesophageal if needed) rapidly confirms or excludes a valvular complication.
If needed, a fluoroscopic study can be used for easy confirmation of the valve leaflet movements.
Treatment
A patient with a suspected valve thrombosis must be referred without delay to a cardiology unit.
The therapeutic alternatives are thrombolysis or, if necessary, surgery. In an emergency situation, the obstructed valve may also be opened by using catheter procedure.
Other complications
Infection of the valve prosthesis is a serious complication and usually requires reoperation.
Fever of unknown origin in a patient with a heart valve prosthesis should be considered an infection of the prosthesis until proven otherwise, and the patient must be referred without delay to specialized care for diagnosis and treatment.
Paravalvular leak may occurimmediately after the operation due to a misshaped valve ring or a suture break.
A leak occurring later may also be caused by a slow infection.
The leak sounds may be quiet, the condition may be associated with increased haemolysis and anaemia, and a severe leak leads to heart failure.
A significant paravalvular leak can be repaired either by repeat heart surgery or by a catheter-based procedure.
The postpericardiotomy syndrome usually appears within a few weeks from the operation. Symptoms suggesting the postpericardiotomy syndrome include low-grade fever, loss of appetite and mild decline in the general condition. ESR and CRP are usually increased, and atrial fibrillation occurs quite often.
The diagnosis should usually be confirmed by echocardiography.
Bioprosthetic valves are increasingly used especially in the treatment of elderly patients (over 60-65 years of age).
Bioprosthetic valves may gradually degenerate, and 10 years after implantation functional defects possibly leading to significant regurgitation or stenosis are already found in up to one valve in three.
In outpatients, bioprosthetic valves are usually monitored annually. If new cardiac symptoms occur or new cardiac findings are made, the patient should be assessed by ultrasonography in specialized care. The severity of the defect and the need for reoperation or catheter intervention is assessed according to the same principles as applied to defects of native valves.
Atrial fibrillation often appears after valve procedures, particularly in elderly patients. It is often either asymptomatic or produces few symptoms. Patients who are not taking anticoagulants should be instructed to monitor their heart rate regularly and be advised of what to do if suspicion of atrial fibrillation arises.
References
Baumgartner H, Falk V, Bax JJ et al. 2017 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J 2017;38(36):2739-2791. [PubMed]
Makkar RR, Thourani VH, Mack MJ et al. Five-Year Outcomes of Transcatheter or Surgical Aortic-Valve Replacement. N Engl J Med 2020;382(9):799-809. [PubMed]
Brouwer J, Nijenhuis VJ, Delewi R et al. Aspirin with or without Clopidogrel after Transcatheter Aortic-Valve Implantation. N Engl J Med 2020;383(15):1447-1457. [PubMed]
Guimarães HP, Lopes RD, de Barros E Silva PGM et al. Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve. N Engl J Med 2020;383(22):2117-2126. [PubMed]
Björn R, Nissinen M, Lehto J et al. Late incidence and recurrence of new-onset atrial fibrillation after isolated surgical aortic valve replacement. J Thorac Cardiovasc Surg 2021;():. [PubMed]