Introduction
Condado et al. reviewed the topic of TAVR and suggests that it might be primary therapy for aortic stenosis [1].
What is TAVR?
TAVR stands for Trancatheter Aortic Valve Replacement with a tissue artificial heart valve. TAVR does not involve surgical aortic valve replacement (SAVR) via thoracotomy. There are many types of Bioprosthetic TAVR’s being used, but it is not my intent to discuss that aspect of TAVR in this document.
General Concerns
My first general concern is that since I do not perform the procedure, but have sent several patients for TAVR, I get concerned about outcome, when many adverse non-cardiac conditions are present in these frequently very elderly and feeble patients. These conditions may negatively influence outcome or at least interfere with expected improvement.
A second general concern is related to who should be doing TAVR. This procedure requires a highly trained, skilled interventional cardiologist. This is not a procedure that should be done by someone who only does a few cases per month.
Work Up for Patient Being Considered for TAVR
Since I do not perform the procedure, I cannot comment on insertion techniques or valve selection. That is up to the interventional cardiologist and surgical consultant. However, I can comment on the work up of the patient from both the clinical and radiologic standpoint and the role of the non-procedure performing cardiologist. This is not a simple matter. The technical aspects of evaluating a patient for TAVR are complex and require not only a skilled interventional cardiologist but a skilled radiologist to evaluate the size of the aorta and the size of the aortic root, and other important parameters. In addition, the patient’s physician (clinical cardiologist) needs to be involved in the clinical decision making, along with the cardiac surgeon assigned to the case.
Contraindications to TAVR
Many of the “contraindications” to TAVR depend on the patient substrate. e.g. elderly feeble patients may not have as good an outcome as very active elderly patients. Not everyone with severe aortic stenosis is a candidate for the TAVR procedure for many reasons listed below.
Symptoms are not related to aortic valve disease.
Many of these patients are quite elderly coming from nursing homes etc. so, it is important to determine, as best one can, the source of the symptoms. e.g. valve failure, lung disease, etc. Old age is always a problem, so elderly patients and patients who have obvious non-cardiac comorbidities, will most probably, not be improved by aortic valve replacement.
Recent Thrombosis, Pulmonary Embolism, or Cardiac Tumor (seen on an imaging modality).
Bleeding or blood clotting problems.
Antiplatelets or anticoagulant after therapy contraindication to their use.
Inadequate aortic annulus size: either too big or too small.
Active endocarditis: this patient should be evaluated by a cardiac surgeon, I.D. physician and a clinical cardiologist, and be treated before any TAVR is performed.
Severe aortic regurgitation: TAVR can be done in these patients, but at this time there is concern about slippage of the valve, after deployment, unless there is calcification in the area of valve insertion.
Active infection anywhere: Since one is implanting a device into the patient and not just doing a cardiac catheterization, the patient needs consultation with infectious disease physicians similar to what we would get for a patient requiring a pacemaker, ICD, BiV. pacer etc.
Coronary ostia at risk for occlusion by an implanted aortic valve device. This has to be determined by a radiologist and interventional cardiologist using imaging techniques.
Valve disease in other major valves that need to be corrected by surgery.
Coronary artery disease: severe and not amendable to PCI but amendable to coronary bypass graph surgery.
Relative Contraindications of TAVR
Cardiac instability: e.g. arrhythmia, recurrent angina, etc. As with any other procedure, patients should have their instability controlled prior to undergoing TAVR.
Allergy to any or all forms of anticoagulation: Many times patients indicate that they have an aspirin allergy. This can be corrected rather simply in the coronary intensive care unit.
Life expectancy less than 12 months: This is a very touchy area and difficult to predict for the individual patient. In addition, many of these patients may be candidates for Hospice care. One could argue that performing a TAVR may provide the patient with “better” 12-month survival (comfort care) than if no TAVR was performed.
“Bicuspid” aortic valve: most of these patients have an aortopathy and some will have coarctation of the aorta. However, most of these valves are calcified and it may be quite difficult to make the diagnosis of “Bicuspid” vs “Tricuspid” aortic valve.
Hypertrophic cardiomyopathy: Perhaps these patients, especially those with HOCM, should undergo alcohol septal ablation if appropriate. But removing resistance to LV emptying may increase the pressure difference in the LV outflow area by increasing systolic anterior motion of the mitral valve and increasing mitral regurgitation.
Low Ao/LV pressure gradient, low aortic valve area: in patients with true aortic stenosis, and thus with an indication for aortic valve replacement, increased cardiac output (as a result of dobutamine infusion-dobutamine stress ECHO), frequently increases the Ao/LV pressure gradient but the aortic valve area remains low.
What is the Role of the Non-procedure Performing Patient’s Physician (Cardiologist)?
There are many things that are not known about TAVR, but what stands out in my mind is how long the transcatheter aortic valve replacement will last. We have a fair amount of information on surgical aortic valve replacement and bio-prosthetic valve durability against which TAVR must be compared. This needs to be explained to the patient and their relatives. However, durability of the valve prosthesis may not be as important in the elderly patient compared to the younger patient who would be expected to live longer than the elderly patient undergoing TAVR. Those patients receiving TAVR can expect durability of the valve of approximately 5 years.
Many other issues need discussion with family, clinical cardiologist, interventional cardiologist and cardiac surgeon, preferably at a group meeting. This is necessary to go over, what is covered in this document and to provide answers to any questions or concerns that the patient of the relatives may have, e.g. why is a dobutamine stress test being done?