Although there have been some reports of self-expanding valvular rupture early after a primary TAVR [1], there has been, within the scope of our search, no report on emergent SAVR for acute AR due to sudden dehiscence of the prosthetic valve leaflet of balloon-expandable long-term after a primary TAVR. From October 2013, when insurance coverage of TAVR began in Japan, until April 2021, when the procedure was performed in this reported case, we performed TAVR for 1303 patients at our institution alone. During this period, only six (0.5%) patients had unscheduled reoperation after TAVR, requiring a repeat surgery. Prosthetic valve cusp rupture, as described above, has also been reported in bioprosthetic valves implanted via SAVR. One study reported a valvular leaflet rupture of the Carpentier-Edwards Magna Ease (Edwards Lifesciences Corp., Irvine, CA, USA) [2], which is similar to SAPIEN XT (Edwards Lifesciences), 8.7 years postoperatively. During the development of the SAPIEN XT, endurance tests were conducted for 200 million beats, equivalent to 25 years of heartbeats, and the results were reported to be comparable to those of Carpentier-Edwards Magna Ease [3]. The SAPIEN XT transcatheter heart valves (THV) removed in the current surgeries were validated by the Edwards Lifesciences Corporation, and manufacturing problems have not been reported. In both cases, the THV was implanted oversized and post-BAV was performed, which may have placed excessive stress on the THV. Unfortunately, no histological evaluation was performed. It is generally stated that bioprosthetic valves may deteriorate over time due to the deposition of calcareous components, growth of autologous tissue, and adhesion of thrombi [4].
The difference in the sewing method between the SAVR and TAVR valve leaflets may possibly have an effect, but unfortunately, a public documentation about how to fix SAVR and TAVR prosthesis leaflets is not provided by the manufacturing company.
Additionally, it has been reported that the durability of surgical bioprosthetic valves is inadequate for younger patients compared to older patients [5], and the current recommendation of preferring older patients for TAVR is appropriate until the long-term results become clearer.
TAVR valve removal requires care, and we carefully detached the frame and intima from the top of the transcatheter aortic valve in a circumferential fashion, bending the valve as we detached it. Nakazato et al. reported an interesting method of removing the valve by cutting the frame longitudinally with nippers to release the radial force [6].
The cause of acute AR in these cases is unclear. Both patients underwent regular follow-ups with TTE and periodic medication adjustments. Patient 1 had undergone a scheduled follow-up 10 days prior to symptom onset. At that time, the patient had no symptoms of heart failure, TTE showed mild paravalvular AR related to SAPIEN XT THV, and the examining physician considered the patient to be doing well. The patient presented with acute heart failure and was suspected to have acute-onset severe prosthetic valve dysfunction. We surmised that the sudden rupture of the prosthetic valve leaflet and the resulting gap caused severe AR, leading to acute heart failure. Patient 2 had no heart failure symptoms 1 year prior to onset, and on TTE, there was only mild paravalvular AR related to SAPIEN XT. Six months prior to the TTE, the paravalvular AR was rated as mild to moderate. During the next 6 months, the valve leaflet ruptured, which caused severe AR, leading to acute heart failure. Additionally, the worsening of AR from mild to moderate at 1-year and 6-month follow-up may have been a predictor of this event. Placement of a THV inside a transcatheter aortic valve (TAV-in-TAV) has been reported as an effective procedure [7]. Since this was a high-risk patient with a history of twice coronary artery bypass grafting procedures, we would have preferred performing TAV-in-TAV. We had to select SAVR because TAV-in-TAV is not covered by insurance in Japan at present. Approval for TAV-in-TAV in Japan is anticipated.
On the other hand, a new problem has occurred. TAV-in-TAV increased the risks for technically impossible coronary access or coronary obstruction, valve thrombosis, and aortic regurgitation due to perivalvular leakage. Mauler-Wittwer et al. reported that TAV-in-TAV was not suitable in 30% of cases due to anatomical limitations and that it was not always feasible [8]. In a report on aortic valve reintervention after TAVR in a real-world multicenter registry, Fukuhara et al. reported that the number of reinterventions increased and TAVR explants among all reintervention procedures are increasing year by year [9].
Currently, SAPIEN XT is not used in Japan, and a modified version, SAPIEN 3, is in use. Pibarot et al. reported that SAPIEN XT had more events than surgical valves over 5 years, but SAPIEN 3 was comparable to surgical valves [10]. SAPIEN 3 is expected to have good durability. Our institution has never experienced leaflet dehiscence with SAPIEN 3. However, it has been only 5 years since the introduction of SAPIEN 3 in Japan, and no conclusion can be drawn. Continued careful follow-up is required.
In conclusion, although the cause of the valvular disease is unknown, we are seriously concerned that the number of similar cases will increase in the future. We should be cautious in expanding the indications of TAVI without evidence of long-term safety.
