Emergent Transcatheter Aortic Valve Implantation Procedure ― Time to Change the Theory ―
Article ID: CJ-23-0034
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Article ID: CJ-23-0034
In recent decades, the treatment of patients with severe aortic stenosis (AS) using transcatheter aortic valve implantation (TAVI) has expanded to include not only high and intermediate surgical risk patients but also low risk patients.1 Previous pivotal clinical trials have demonstrated a better prognosis of TAVI compared with other medical treatments, including balloon aortic valvuloplasty (BAV), but similar to that of surgical aortic valve replacement (SAVR).2,3 However, the potential advantage of non-elective (i.e., emergent) TAVI for AS patients in a critical condition is still debated. There are no definitive conclusions regarding the usefulness of emergent TAVI compared with other therapeutic approaches, partly because of the diverse backgrounds of patients and the difficulty of gaining bioethics approval to conduct randomized trials. Therefore, the treatment approach for patients with AS in unstable condition is likely to be determined by individual centers.
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In this issue of the Journal, Kitahara et al4 publish the clinical outcomes of urgent/emergent TAVI using data from the representative national-based Japan-Transcatheter Valve Therapies (J-TVT) registry. Although salvage TAVI cases were excluded from their study, the 30-day and 1-year mortality rates for urgent and emergent cases were 6.7% and 22.8%, respectively. Considering this cohort’s higher surgical risk and multiple comorbidities, the authors suggest that emergent TAVI procedures were successfully performed. In addition, the mortality rates in the study were comparable to those reported in previous studies. The 30-day mortality rate with emergent TAVI ranges from 3.3% to 23.8% and the 1-year mortality rate from 10% to 30%.5,6 The Society of Thoracic Surgeons-American College of Cardiology (STS/ACC) Transcatheter Valve Therapy (TVT) registry, using data from 3,952 urgent/emergent TAVI cases, reported that the 30-day mortality rate was 8.7% and the 1-year mortality rate was 29.1%.7 Large-scale, multicenter Japanese TAVI data from the Optimized Transcatheter Valvular Intervention (OCEAN)-TAVI registry also revealed 30-day and 1-year mortality rates of 9.2% and 29.3%, respectively, for emergent TAVI.8 Although the results of the OCEAN-TAVI registry included “salvage” cases in addition to urgent/emergent cases, the current study results showed similar or better clinical results than in the STS/ACC/TVT and OCEAN-TAVI registries.
As for other therapeutic approaches for patients in unstable condition, there are also few reports of emergent SAVR. Classical data demonstrated a 30-day mortality rate >30% after emergent SAVR.9 A very small number of single-center studies showed a 30-day mortality rate of 5% for emergent SAVR, whereas the estimated operative risk between TAVI and SAVR was significantly different.10 The TAVI procedure is less invasive than SAVR, so selection bias is clinically inevitable when selecting between TAVI and SAVR for patients in emergent conditions. BAV may play an important role for AS patients in an unstable condition. Physicians can choose BAV as a bridge to future additional TAVI or SAVR when the patient’s condition improves. Nonetheless, the 30-day mortality rate of emergent BAV for critical patients was 33%, reflecting the lower treatment effect of BAV compared with TAVI.5
The question then arises: even if the physician decides that emergent TAVI should be performed, can it be performed in all TAVI centers in Japan? As the authors point out, urgent/emergent TAVI procedures are performed only in limited numbers in Japan compared with other Western countries. Several barriers to emergent TAVI are different centers’ experiences, heart team considerations, multidisciplinary approaches, and the regulation of TAVI setups that allows the procedure to be performed in hybrid operating rooms. However, if invasive therapy, including TAVI, is not performed at the appropriate time, the patient’s prognosis is definitively affected. According to a previous study, patients with a history of TAVI refusal, even just once, and those who eventually underwent the procedure, had a significantly worse prognosis.11 This current study showed that the 1-year mortality rate in the elective group was 10.3%, whereas that of delayed TAVI due to the patient’s refusal of the first TAVI procedure was 28.8%.11 Even if the patient survives after refusing TAVI, the malignant cycle of readmission continues. In addition, the prognosis worsens when patients with severe AS are medically treated. Among the inoperable or high surgical risk cohort, patients with severe AS with medical or BAV treatment showed a 1-year mortality rate of 50.7% and a 2-year mortality rate of 68.0%.2 Thus, conservative medical treatment for severe AS is associated with a worse prognosis than for emergent TAVI.
According to the results of previous and current registry data, we can propose a risk-benefit analysis of invasive and non-invasive treatments for critical AS patients (Figure). The final decision regarding the indication for emergent TAVI must take into consideration the patient’s background, such as multiple comorbidities, frailty status, life expectancy, social support, and procedural risk. We should also respect patient preference as an important factor in deciding on invasive therapy, and thereafter, high-quality, lifelong supportive care can be considered. Adequately managing AS patients with unstable condition remains a challenge. However, the number of emergent TAVI cases in Japan’s aging society is expected to increase annually. Therefore, the heart team at TAVI centers is required to adapt emergent TAVI to save critical AS patients. Ten years have passed since the introduction of TAVI in Japan, and as both the technology and our understanding of the procedure advance, we may be at a tipping point of the conventional theories.
Risk-benefit analysis of each treatment for critical aortic stenosis (AS) patients. After emergency admission, AS patients (or their families or caregiver) can be provided with clinical information by the heart team. Although challenging in an emergent situation, we should explain the risks and benefits of each option based on the estimated risk of invasive and noninvasive treatments. Finally, patients can choose the treatment option that leads to an appropriate clinical course.
M.Y. is a clinical proctor for Edwards Lifesciences and Medtronic. M.Y. receives lecture fees from Edwards Lifesciences, Medtronic, and Daiichi-Sankyo. T.S. receives lecture fees from Edwards Lifesciences, Medtronic, and Daiichi-Sankyo.
