Aortic stenosis (AS) is the most prevalent valvular disease and the one that most frequently requires surgery or percutaneous intervention in Europe.1,2 In developed countries, the occurrence of this condition is mainly due to degenerative calcification of the aortic valve.2–4 Consequently, as the population ages, the prevalence of aortic stenosis continues to rise, with approximately 3.4% of patients over the age of 75 having severe AS.5

Severe AS presents with exertional dyspnea, chest angina, presyncope, or syncope.6,7 Echocardiography is the gold-standard test for confirming the diagnosis and assessing the severity of AS, based on the mean aortic transvalvular gradient (ΔPm), the maximum aortic transvalvular velocity (Vmax), and the aortic valve area (AVA).8–11

It is known that, once symptoms appear, the average survival of patients without appropriate intervention is two to three years.3,7 Therefore, timely intervention is crucial. The only effective treatment for severe AS is aortic valve replacement (AVR), which can be performed via surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI). TAVI has been validated as an effective alternative to conventional surgery, particularly in older patients (≥75 years), those with multiple comorbidities, or those at high surgical risk.8

Despite the significant improvements observed, the quality of management of patients with severe AS remains suboptimal in various European hospital centers.12,13 Currently, there are no guidelines or recommendations on the waiting time from diagnosis to intervention issued by the European Society of Cardiology (ESC). However, intervention should take place as soon as possible to reduce the risk of heart failure (HF) and death.14 The Canadian Wait Time Alliance has established a benchmark maximum waiting time for SAVR of 42 days for elective cases and 14 days for urgent cases.15 More recently, wait time guidelines for TAVI were published and approved by the Canadian Cardiovascular Society (CCS), setting a maximum waiting time of 84 days for elective cases and 14 days for urgent cases.16

With the increasing prevalence of this condition, there is a potential overload on surgical centers, which may in turn lead to prolonged waiting times for valve intervention.

This study aims to assess the time from referral to the surgical center to the valve intervention in a sample of patients diagnosed with severe AS and to evaluate the impact this wait time may have on hospitalization and mortality among patients on the waiting list.

This is a retrospective, observational, descriptive, and analytical study conducted in the Cardiology Department of Local Health Unit of Braga.

Patients with a diagnosis of severe native valve AS confirmed by echocardiography performed at Hospital of Braga, who were either followed in cardiology outpatient consultations or hospitalized at this institution, and who were referred to the surgical reference center between January 2018 and December 2021 or died while on the waiting list for intervention during this period, were consecutively included (n=241).

Patients <18 years of age, those who had previously undergone aortic valve procedures, those who did not meet the criteria for intervention, or those who refused the procedure were excluded. Clinical information was collected based on access to the patients’ electronic medical records, including follow-up data. Wait times were calculated according to the definitions described in the Quality Indicators for TAVI document recommended by the CCS, and were also applied to SAVR (Table 1).16,17 Patients who had been previously referred for elective SAVR and required hospitalization followed by urgent intervention were not included in the calculation of total or time-to-intervention waiting periods.

Our study showed (1) a significant predominance of SAVR over percutaneous valve intervention (SAVR: 83.9% vs. TAVI: 16.1%); (2) wait times in the outpatient setting were considerably higher than recommended (median of 226 days for SAVR and 426 days for TAVI); (3) a progressive increase in adverse cardiovascular events, namely hospitalization due to HF and mortality, relative to the waiting time in the outpatient setting; (4) waiting times for SAVR and TAVI in the inpatient setting were in line with the recommended guidelines.15,16,22

Approximately 84% of patients underwent SAVR. Data regarding TAVI show that in Portugal, there is underutilization of this intervention compared to other European countries. In January 2017, we were performing about 40 TAVI procedures per million inhabitants, with this number increasing to 72 in 2019 after being included in the Valve for Life initiative.23 In Germany, France, and the UK, TAVI is already preferred over SAVR, and is performed in about 71.9% of patients undergoing intervention.13

The Portuguese Society of Cardiology and the Portuguese Society of Thoracic and Cardiovascular Surgery published a consensus statement on the maximum waiting time for heart surgery. The document sets maximum waiting times of two weeks for patients with severe symptoms, six weeks for patients with mild to moderate symptoms (NYHA class II), and 12 weeks for less severe elective patients.22 As the guidelines for wait times approved by the CCS are more recent, they were used as the reference for this study. For SAVR, the recommended waiting times are 42 days for elective cases and 14 days for urgent cases.15 For TAVI, the recommended waiting times are 84 days for elective cases and 14 days for urgent cases.16

In an inpatient setting, although the waiting time for TAVI is longer than for SAVR, our results are in line with the waiting time limit established by the CCS. However, the waiting times in the outpatient setting were considerably higher than recommended: the median total waiting time for SAVR and TAVI was 226 and 426 days, respectively; the median time-to-decision for SAVR and TAVI was 82 and 319 days, respectively; and the median time from decision to intervention for SAVR and TAVI was 133 and 136 days, respectively.

One possible explanation for these numbers is the likely overload of the surgical center's capacity. Known data in Portugal show that valvular disease accounts for half of the surgical activity in hospitals within the National Health Service network and has consistently increased over the past years. Data from 2015 on Cardiac Surgery showed that Portugal ranks in the middle of the table for the number of cases per million inhabitants (589 cases/million inhabitants), compared to other European countries. However, it has the lowest number of centers per million inhabitants (0.6 centers/million inhabitants).22 However, there are no similar published data for TAVI yet. On the other hand, it was observed that the vast majority of patients undergoing TAVI at the center where this study was conducted first attend a thoracic cardiac surgery consultation before being referred to the structural interventional cardiology consultation. This referral system, which is not transferable to other hospitals, likely explains the delay in the decision-making process for TAVI: although the time from decision to intervention is similar for both procedures, the time-to-decision for TAVI is nearly four times longer than for SAVR.

A Canadian retrospective study showed that the median waiting time for SAVR was 50 days and for TAVI it was 84 days.24 Additionally, another study evaluated different time intervals in a population of patients undergoing TAVI. Thus, the median total waiting time was 105 days; the median time from referral to decision was 54 days; and the median time from decision to intervention was 34 days.25

In our study, we found that 13% of patients required hospitalization due to HF while on the waiting list, with 70.8% of these undergoing urgent SAVR due to worsening of their condition; mortality on the waiting list reached 6%. Similar studies have shown that the probability of hospitalization on the waiting list ranges from 3.6% to 12%, and the risk of death on the waiting list for SAVR in clinical practice varies from 2% to 14%.24–29

After 90 days on the waiting list, only 4.9% of patients had undergone SAVR. Most patients were intervened after 180 days of waiting, and most of the events occurred after this period. On the other hand, a study conducted at three European centers showed that after three months of waiting, 82.3% of patients had already undergone intervention.13

The wait times in our study are significantly higher compared to other countries in Europe and around the world and are much higher than those recommended by the guidelines, which could impact the mortality and hospitalization of patients on the wait list. With the anticipated increase in the prevalence of AS, if no measures are taken, the overload of surgical centers will become increasingly noticeable. In fact, regarding cardiac surgery, we are facing a higher average number of cases per surgical center compared to most European countries. On the other hand, the number of TAVI interventions performed in Portugal per million inhabitants, compared to other European countries, is substantially lower.

The conducted study should be interpreted in the context of several limitations. Firstly, the sample size: the data collection method used did not allow us to assess the actual number of patients intervened over the four years, as patients who underwent echocardiography at an external facility to the Hospital of Braga were not included in the study. Secondly, this study only evaluated the occurrence of surgical complications or adverse events within 30 days after the valve intervention. It would be interesting to extend the follow-up period for patients after intervention, as some recovery quality markers (echocardiographic, clinical, analytical findings, etc.) require more time to become evident. On the other hand, the center where the study was conducted does not have a cardiac surgery service or a structural intervention team for TAVI placement, so the results may differ from centers with these same capabilities. Finally, our study is observational, so there may be confounding factors associated with it, and it is single-center, which limits the extrapolation of waiting times to other regions of the country.

In summary, in the studied population, the most frequent valve intervention for the treatment of severe AS is SAVR. In both settings, the wait time for TAVI is longer than for SAVR. In the outpatient setting, the waiting times found in our study are considerably higher than those recommended. Prolonged wait times in the outpatient setting are associated with adverse events, namely hospitalization and mortality while on the waiting list.

In the future, this study could serve as a reference for analyzing wait time management in other surgical centers. Equally important is the reflection within the community of cardiologists, cardiac surgeons, and interventional cardiologists on the quality of management for patients with severe AS in Braga.

Braga Hospital Ethics Commission. Reference number: 60_2022.

The authors declare no conflicts of interest.