Exercise-based Cardiac Rehabilitation in Patients With Aortic Stenosis After Transcatheter Aortic Valve Implantation

Effect of Physiotherapist-led Exercise-based Cardiac Rehabilitation in Older Patients With Aortic Stenosis Who Have Undergone TAVI?

Aortic valve stenosis (AS) is the most common valve disease among older individuals. In symptomatic AS, mortality is high, and the only treatment that improves prognosis and survival is transcatheter aortic valve implantation (TAVI). TAVI is a growing treatment in Sweden, allowing previously inoperable older patients with AS, who are often frail and have comorbidities, to receive intervention. This results in the need for postoperative cardiac rehabilitation for patients treated with TAVI. Previous systematic reviews and meta-analyses examining the effect of physiotherapist-led exercise-based cardiac rehabilitation (PT-X) after TAVI have shown that participation in PT-X can improve physical fitness (the highest measured oxygen uptake (VO2peak)), walking distance, walking speed, and health-related quality of life (HR-QoL). However, the included studies are limited, and there is selection bias, resulting in low evidence. Therefore, access to PT-X is currently almost non-existent in Sweden. As more patients undergo TAVI, it is crucial to investigate whether PT-X after TAVI can further improve physical fitness, HR-QoL, and reduce hospital admissions in older individuals with AS.

Objective: Primary, to investigate whether participation in PT-X after TAVI can impact physical fitness, physical activity level, and health-related quality of life. Secondary, to study the prevalence of frailty and the number of hospital admissions during the first postoperative year after TAVI.

Expected outcome: If patients with AS who have undergone TAVI can improve physical fitness, it could potentially strengthen the evidence and optimize the patient's physical capabilities. Increased access to PT-X and awareness of frailty in these patients could reduce the risk of falls and possibly the number of hospital readmissions. This would decrease healthcare consumption and improve the patient's quality of life.

Aortic valve stenosis (AS) is the most common valve disease with the highest prevalence in older individuals. Healthcare is unequal, with women receiving specialist care and interventions less frequently than men. They also receive the diagnosis later, and mortality rates are higher. AS develops over time, and in the presence of symptomatic AS such as angina pectoris, syncope, and heart failure, the prognosis is poor, and mortality is high. If untreated, AS is a disease with a 2-year relative mortality risk of 50%. In older patients at high risk with symptomatic AS, transcatheter aortic valve implantation (TAVI) is the only medical treatment that improves prognosis and survival.

Since 2008, TAVI has been performed in Sweden as a standard treatment with priority 3 in the the recommendations given by the National Board of Health and Welfare in Sweden. The number of TAVI procedures in Sweden is steadily increasing and now exceeds isolated open aortic valve surgery. This development allows patients with severe symptoms and high risk, who were previously inoperable, to undergo valve intervention.

Frailty is a condition where at least three of the following criteria should be met: involuntary weight loss, self-reported fatigue, sarcopenia, reduced physical capacity, slow walking speed, and low physical activity level. Studies show that 50-70% of those undergoing TAVI due to AS are defined as frail elderly individuals with comorbidities such as heart failure and renal failure. Furthermore, studies have demonstrated an increased risk of falls and difficulty participating in daily activities due to reduced peak oxygen uptake (VO2peak), short walking distance, lower walking speed, and impaired Health Related Quality of Life (HR-QoL). It is well-established that a low VO2peak correlates with increased risk of premature death in both healthy individuals and those with chronic disease (19). Moreover, there is a strong correlation between a short walking distance and prognosis in patients with chronic diseases.

Since patients with AS already have reduced physical fitness preoperatively, a prolonged recovery time is usually observed postoperatively. Systematic reviews and meta-analyses examining the effect of physiotherapist-led exercise-based cardiac rehabilitation (PT-X) after TAVI have shown that participation in PT-X can improve VO2peak, walking distance, walking speed, and HR-QoL. However, the included studies are few and exhibit varying study quality, leading to selection bias. Despite this, the opportunity to participate in PT-X after TAVI is virtually non-existent in Sweden due to low evidence, and national and international cardiac care guidelines do not mention the possibility of PT-X after TAVI.

This has resulted in patients who have undergone TAVI not being recommended PT-X as part of their medical treatment, unlike conditions such as heart failure and ischemic heart disease, which have high priority and high evidence. As more patients undergo TAVI, it is of utmost importance to investigate whether PT-X after TAVI can further improve physical capacity, quality of life, and reduce hospital admissions.

Objective: Primary, to investigate whether participation in PT-X after TAVI can impact physical fitness, physical activity level, and health-related quality of life. Secondary, to study the prevalence of frailty and the number of hospital admissions during the first postoperative year after TAVI.

How will participation in PT-X impact exercise capacity compared to the control group that is allowed to continue with their usual life? How will participation in PT-X impact the muscle function compared to the control group that is allowed to continue with their usual life? How will participation in PT-X impact the patients physical activity level compared to the control group that is allowed to continue with their usual life? How will participation in PT-X impact HR-QoL compared to the control group that is allowed to continue with their usual life?

Secondary Research Questions:

What is the prevalence of frailty in the study population that has undergone 12 weeks of PT-X compared to the control group? What is the incidence of hospital admissions in patients who have undergone 12 weeks of PT-X compared to the control group?

Method:

Study Population: Patients, 65 years or older, with AS who have undergone TAVI and are being followed-up at SV Alingsas Hospital will be invited to participate in an intervention study. The control group consists of matched controls based on age, gender, and exercise capacity in watts, followed up at Sahlgrenska University hospital in Gothenburg. Patients in the control group will be approached for participation by a research nurse from Sahlgrenska Universityhospital. All patients will be informed verbally and in writing, and informed consent will be obtained. The study follows the Helsinki Declaration,

Data Analysis and statistical power:

Ratio and interval data will be presented as mean ± 1 standard deviation, ordinal data as median and interquartile range, and nominal data in absolute and relative numbers.

Depending on normal distribution, Student's T-test or Mann-Whitney's U-test will be used to examine differences between groups.

Paired T-test or Wilcoxon signed-rank test will highlight within-group differences, and Chi-square test will study differences in nominal data.

Multiple regression will be used to study the relationship between group membership and the primary outcome measure, work capacity in watts.

Statistical power was calculated with an 80% power (β) to detect a statistically significant difference (α) at 5%. For the training group to achieve a significant (p=0.05) improvement of 10 watts in work capacity compared to the control group, 56 individuals must be included in each group. Considering a potential dropout of approximately 20%, a total of 135 individuals will be included in the study.

Expected Result / Clinical Significance:

If patients with AS who have undergone TAVI can improve physical fitness, it could potentially strengthen the evidence and optimize the patient's physical fitness.

Increased access to PT-X and awareness of frailty in these patients could reduce the risk of falls and possibly the number of hospital readmissions, leading to reduced healthcare consumption and increased quality of life for the patient.

Gender Perspective of the Project:

The study will include both men and women to achieve groups as similar as possible regarding gender, age, and exercise capacity in watts.

Inclusion Criteria:

• Aortic stenosis treated with TAVI.

Exclusion Criteria:

• Patients who, due to another disability, cannot perform the study protocol for physical fitness, PT-X, or complete the questionnaires included in the study.