Ask the Expert
Transcatheter Aortic Valve Replacement for Aortic Stenosis: What Geriatricians Should Know and How They Can Help
Aortic stenosis is a narrowing of the aortic valve opening that impedes blood flow. In the United States, the condition affects 5% of the general population by age 70 and 20% by age 90. The condition ranges from mild to severe, with mild cases producing no symptoms. As the disease progresses and the aortic valve further narrows, common symptoms include angina, syncope, and dyspnea. Once these symptoms occur, survival rates decrease dramatically, with only 50% of symptomatic patients being alive at 2 years and only 20% being alive at 5 years. The only definitive treatment options for aortic stenosis include an open-heart procedure that replaces the damaged aortic valve with an artificial one, and transcatheter aortic valve replacement (TAVR), which places the SAPIEN artificial heart valve using a minimally invasive approach. The US Food and Drug Administration (FDA) approved TAVR in November 2011 for use in patients who are not candidates for open-heart procedures, and, in October 2012, it expanded its approval to include high-risk patients (ie, those eligible for open-heart procedures but at high risk for serious surgical complications or death).
Clinical Geriatrics® (CG) had the opportunity to discuss TAVR with Bruce Bowers, MD, Medical Director of Invasive and Non-invasive Cardiology, Medical City Dallas, Dallas, TX, to get an update about the procedure and the role that geriatricians can play in improving diagnosis and outcomes.
CG: When we interviewed your colleague Todd Dewey, MD, about TAVR last year at the 2012 American Geriatrics Society Annual Meeting, he indicated that knowledge of this treatment option is still lacking, especially among specialties outside of cardiology, resulting in the condition being undertreated and under-referred. He mentioned that an estimated 40% of patients are not being sent for therapy. Are you still finding this to be the case, even now that the FDA has expanded its approval to include high-risk patients?
Dr. Bowers: Aortic valve replacement is the only definitive therapy for the treatment of symptomatic severe aortic stenosis. There is a 50% mortality rate at 2 years for patients who suffer with this valvular heart problem. The vast majority of patients with aortic stenosis are over the age of 65. At our center, over the past several years, the average age of patients we have seen at the Dallas Valve Institute is over 80 years old. Many of these patients have multiple comorbidities, including diabetes, coronary disease, and hypertension. They are usually significantly debilitated and frail. Thus, they are often deemed too high risk to be considered for aortic valve replacement when evaluated by primary care physicians in the outpatient setting. This results in intermediate to high-risk patients being under-referred for consideration of aortic valve replacement, even TAVR. Despite the FDA approval for TAVR, which was granted for these higher risk patients, we still have a significant lack of awareness of the minimally invasive treatment options that are available, across primary care practitioners. Today, the number of patients eligible for valve replacement who are not referred still hovers around 40%.
How can geriatricians ensure a more timely diagnosis of aortic stenosis (ie, what should they specifically be looking for) and when should they refer a patient to a cardiologist for further evaluation?
The first clue to the diagnosis is typically the systolic ejection murmur that is detected on physical examination. The classic murmur along with a provocative questioning of the patient about symptoms of decreased exercise tolerance, diminished ability to perform daily living activities, congestive heart failure, angina or syncope, tend to make the diagnosis. Affirmative answers to any of these questions should prompt referral to a cardiologist familiar with the latest treatments available for aortic stenosis.
Once a patient is handed off to a cardiologist, is there still a role for the geriatrician to play, including with regard to follow-up care?
The geriatrician is critical to the successful treatment of the advanced-age, high-risk aortic stenosis patient. The geriatrician has the expertise to manage the multiple comorbidities and polypharmacy that are common in this group of patients. Ideally, the geriatrician should be part of the initial evaluation of these patients in an integrative, multidisciplinary valve clinic. We would welcome the opportunity to have a geriatrician in our clinic and be a meaningful part of our team. Certainly, if the geriatrician were involved in the outpatient evaluation, the in-patient management, and the postoperative follow-up, the patient would benefit.
Can you talk about the outcomes following TAVR, including what’s been observed with regard to complications and morbidity and mortality rates?
In the high-risk aortic stenosis cohort, the mortality rate for TAVR versus conventional aortic valve replacement (CAVR) was equivalent at 2-year follow-up. There is a higher incidence of stroke in the TAVR group when compared with CAVR. Improved operator experience with TAVR, new iterations of TAVR technology, and improved preoperative screening of patients will likely result in a decrease in the stroke rate seen in the initial studies of TAVR.
Particularly in medicine, there is often concern about using first-generation devices. Currently, the next-generation SAPIEN heart valve, SAPIEN XT, is in clinical trials. Can you outline what improvements have been made?
The second- and third-generation SAPIEN technologies offer several advantages. They are lower profile, allowing them to be delivered through smaller femoral arteries. They are also available in a number of sizes to allow the valve to be better matched for each patient’s particular anatomy.
It is always interesting hearing some personal accounts. Are there any cases, in particular, that stand out in your mind?
Being involved in the development of a new treatment option for patients that have been told they have no option is always a great feeling. It is particularly gratifying when many of the men and women we have the privilege of treating are octogenarians who have sacrificed so much for our country. To return the favor to World War II veterans and their loved ones, with a cutting-edge technology such as TAVR, is a great experience.
Do you have any concluding thoughts you’d like to share with geriatricians and physicians caring for elderly persons?
I hope that over time, geriatricians, cardiac surgeons, and cardiologists can forge a multidisciplinary team to address the medical complexities of these patients. Geriatricians should not be timid about getting involved with this treatment for their patients. We would welcome it!
Disclosures: Dr. Bowers is a paid consultant to Edwards Lifesciences, manufacturer of the SAPIEN heart valve.