Aortic Valve Replacement (AVR) and Transcatheter aortic-valve replacement (TAVR)
Severe aortic stenosis is defined with an aortic transvalvular velocity ≥4 m/sec and an aortic valve area ≤1 cm2. There are multiple treatment options, including: medical optimization, percutaneous balloon aortic valvotomy, transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR). The choice of intervention will depend on patient's anticipated life expectancy and functional status.
Cardiology
InShort
PART 1:
Aortic Valve Replacement
by Cheng-Hung Tai, MD and
David B. Grossberg, MD, FACC
Aortic valve replacement (AVR) is a surgical procedure that is indicated for severe aortic stenosis(AS). Severe aortic stenosis is defined with a maximum aortic transvalvular velocity ≥4 m/sec and an aortic valve area ≤1 cm2. There are multiple treatment options, including: medical optimization which is usually of limited benefit at this grade of valvular stenosis, percutaneous balloon aortic valvotomy which is mostly a palliative treatment with only short-term benefits and high procedural risks and periprocedural CVA risks, transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR). The choice of intervention will depend on patient's anticipated life expectancy and functional status.
Indications
A diagnosis of severe aortic stenosis can be made on physical examination but always necessitates a transthoracic echocardiography. Next, a heart valve replacement team should be consulted to assess the patient. If the patient's life expectancy is felt to be greater than 1 year if a surgical aortic valve replacement or transcatheter aortic valve replacement is performed AND if it is expected that the SAVR/TAVR procedure will improve the patient's quality of life, then the patient can be surgically risk assessed for TAVR or SAVR.
Patients that are low to intermediate surgical risk with an inaccessible transfemoral TAVR (or any other adverse anatomic features) are recommended to undergo SAVR. Extreme and high surgical risk patients with an accessible transfemoral approach for TAVR are recommended to undergo TAVR. If this is not possible, then a careful risk/benefit assessment should be done to look for alternative sites for access for TAVR, or have the patient's medical therapy optimized.
Current AHA/ACC guidelines for SAVR in patients with AS are as follows:
Symptomatic severe high gradient AS
Asymptomatic severe AS with left ventricular ejection fraction (LVEF) <50%
Severe AS when undergoing coronary bypass or other cardiac surgery
The latter two are strong considerations for valve replacement given risk for rapid disease progression:
Asymptomatic very severe AS and low surgical risk
Asymptomatic severe AS with decrease in systemic blood pressure or exercise tolerance during physical activity.
The recently published SURTAVI trial showed TAVR is non-inferior to SAVR in a large randomized cohort of intermediate risk patients. (1)
Primary endpoint: All-cause mortality or disabling stroke for TAVR vs. SAVR at 24 months: 12.6% vs. 14.0%, p < 0.05 for non-inferiority
Coronary Revascularization Results: After randomization to treatment, there were 169 TAVR and PCI patients, 163 SAVR and coronary artery bypass grafting (CABG) patients, 695 TAVR only patients, and 633 SAVR only patients. Complete revascularization was not significantly different between TAVR + PCI vs. SAVR and CABG. No significant difference in the rate of the primary endpoint was found between TAVR and PCI, and SAVR and CABG.
Overall Results: The results of this landmark trial indicate that TAVR is non-inferior to SAVR for the primary endpoint of mortality/disabling stroke at 24 months for the treatment of severe symptomatic aortic stenosis in intermediate-risk patients. Vascular complications were higher in TAVR patients at 30 days (6.0% vs.1.1% with SAVR). In the patients getting SAVR some complications were more frequent: new-onset atrial fibrillation was higher in the SAVR group (43% vs.12.9% with TAVR), as was the incidence of acute kidney injury, and the need for blood transfusions. 25.9% of patients required a new pacemaker post-TAVR, compared with 6.6% post-SAVR. Valve performance at 2 years was similar between the two strategies. From the patient’s perspective, TAVR provided earlier symptomatic benefit, but at 2 years of follow-up, symptoms were similar in both the TAVR and SAVR groups. Functional status improvement was also faster among patients undergoing TAVR rather than SAVR, but functional status measurements were similar in both groups at both 1 and 2 years of follow-up.
On 5-year follow-up, clinical outcomes were similar. There were more repeat valve interventions post-TAVR, but the majority were within the first 2 years.
This is a landmark trial in this field. Longer-term follow-up is going to be essential to understand long-term performance and the risk of other complications such as sub-clinical leaflet thrombosis which may lead to increased embolic events, and structural valve degeneration which can lead to increased risk of aortic insufficiency (AI).
Sources and further reading:
Nishimura RA, Otto CM, Bonow RO, et al. 2017 AHA/ACC Focused Update of the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017;70(2):252-289.
Vahanian A, Alfieri O, Andreotti F, et al. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 2012;33(19):2451-96.
Goel SS, Agarwal S, Tuzcu EM, et al. Percutaneous coronary intervention in patients with severe aortic stenosis: implications for transcatheter aortic valve replacement. Circulation. 2012;125(8):1005-13.
(1) Tuttle MK, Kiaii B, Van Mieghem NM, et al. Functional Status After Transcatheter and Surgical Aortic Valve Replacement: 2-Year Analysis From the SURTAVI Trial. JACC Cardiovasc Interv 2022;15:728-38.
Editorial Comment: Wood DA, Sathananthan J. The Next Frontier in TAVR: Identifying Nonresponders and Treating Concomitant Pathologies. JACC Cardiovasc Interv 2022;15:728-38.
PART 2:
Transcatheter Aortic-Valve Replacement
by Andrew Kupersmith, M.D.
Transcatheter aortic-valve replacement (TAVR) often is performed in a manner similar to conventional cardiac catheterization. A folded balloon-mounted bioprosthetic valve is inserted via a femoral artery, advanced across the diseased aortic valve (stenotic, insufficient, or both), and then deployed by inflating the balloon. If a patient does not have femoral arteries of sufficient caliber, TAVR may be performed via a surgical approach through a small left lateral chest incision and then advanced through the left ventricular apex and across the native aortic valve. This obviates the need for a full sternotomy. Before being considered for a TAVR procedure, a patient must be evaluated at a center that performs the procedures frequently.
Pear to Know
TAVR procedures are recommended, and currently are only commercially approved, for patients who are poor candidates for standard surgical-valve replacements. Such patients tend to be older and too frail to tolerate a sternotomy procedure involving general anesthesia. Ongoing studies are evaluating the efficacy of TAVR procedures in healthier people.
Author: Andrew Kupersmith
Editor’s Comment- “TAVR may be performed via a surgical approach through a small left lateral chest incision”. In the early days of TAVR, the chest wall approach was anterolateral. I suspect that this approach in women may have seen a significant incidence of chest wall infections including MRSA.
FibonacciMD.app Compendium (our medical encyclopedia) has over 6,000 medical terms and medications.