• Quality of recovery: QoR-15 [ Time Frame: 3 months postoperative ]
  The quality of recovery after surgery and anaesthesia is measured using the QoR-15 questionnaire. The resulting score indicates self-reported patent well-being and perceived support with higher scores (0-100) indicating a better quality of recovery. (8)
• Health related quality of life: Questionnaire Short Form-12 (SF-12) [ Time Frame: preoperative, 3 months postoperative ]
  The World Health Organisation Disability Assessment Schedule (WHODAS) assesses six domains of functioning relating to the quality of life. Quality of life is measured using the Questionnaire Short Form-12 (SF-12), which indicates physical and psychological wellbeing. Higher scores indicate a better health related quality of life.
• Activities of daily living [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  The Lawton-Brody Instrumental Activities of Daily Living is used to assess the ability to perform activities that are central to living independently. A lower score indicates better functioning. The score ranges between 8 - 31
• Cognitive performance [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  Cognitive funtioning will be tested with the Montreal Cognitive assessment (MOCA), a standardised test that includes memory recall, verbal fluency and visuospatial abilities. A total score between 0 and 30 is calculated with a higher score indicating better cognitive functioning.
• Mobility [ Time Frame: preoperative, 3 months postoperative ]
  The time up&go-test, in which the subject starts from a sitting position, walks a defined distance of 3 m and returns to a sitting position on a chair is indicative of fall risk and mobility. The chosen cut-off in this study is 10 seconds.
• Muscle strength [ Time Frame: preoperative, 7 days postoperative ]
  Grip strength is widely used in the diagnosis of frailty and sarcopenia. It will be measured with a hand held dynamometer in kg, using the dominant hand if possible.
• Incidence of postoperative complications [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  Complications reported in hospital files or patient interview
• Duration of hospital admission [ Time Frame: 3 months postoperative ]
  Day of admission to day of discharge

• Quality of recovery: QoR-15 [ Time Frame: 3 months postoperative ]
  The quality of recovery after surgery and anaesthesia is measured using the QoR-15 questionnaire. The resulting score indicates self-reported patent well-being and perceived support with higher scores (0-100) indicating a better quality of recovery. (8)
• Health related quality of life: Questionnaire Short Form-12 (SF-12) [ Time Frame: preoperative, 3 months postoperative ]
  The World Health Organisation Disability Assessment Schedule (WHODAS) assesses six domains of functioning relating to the quality of life. Quality of life is measured using the Questionnaire Short Form-12 (SF-12), which indicates physical and psychological wellbeing. Higher scores indicate a better health related quality of life.
• Activities of daily living [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  The Lawton-Brody Instrumental Activities of Daily Living is used to assess the ability to perform activities that are central to living independently. A lower score indicates better functioning. The score ranges between 8 - 31
• Cognitive performance 1 [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  The Demtect (dementia detection) is a screening tool for mild cognitive impairment, which tests word list learning, verbal fluency, late recall and digit span reverse. A total score between 0-18 is calculated with a higher score indicating better cognitive functioning.
• Cognitive performance 2 [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  Cognitive funtioning will be tested with the Montreal Cognitive assessment (MOCA), a standardised test that includes memory recall, verbal fluency and visuospatial abilities. A total score between 0 and 30 is calculated with a higher score indicating better cognitive functioning.
• Mobility [ Time Frame: preoperative, 3 months postoperative ]
  The time up&go-test, in which the subject starts from a sitting position, walks a defined distance of 3 m and returns to a sitting position on a chair is indicative of fall risk and mobility. The chosen cut-off in this study is 10 seconds.
• Muscle strength [ Time Frame: preoperative, 7 days postoperative ]
  Grip strength is widely used in the diagnosis of frailty and sarcopenia. It will be measured with a hand held dynamometer in kg, using the dominant hand if possible.
• Incidence of postoperative complications [ Time Frame: preoperative, 7 days and 3 months postoperative ]
  Complications reported in hospital files or patient interview
• Duration of hospital admission [ Time Frame: 3 months postoperative ]
  Day of admission to day of discharge

As a consequence of the increasing life expectancy hospitals are seeing a growing number of elderly patients undergoing elective surgery. These patients are likely to suffer from one or more chronic illnesses, malnutrition, reduced physical strength and mobility and sensory impairment. Age related loss of resilience in combination with these conditions often results in frailty. Frailty syndrome describes a reduction in weight, mobility and strength, as well as declining cognitive capacities and reduced performance in daily life activities. This decline in constitution is accompanied by an increased risk of complications and mortality in the period after surgery. Frail patients are generally admitted to hospital for a longer period and are readmitted more often.

A multitude of studies has demonstrated that these risks can be significantly reduced by offering frail patients a prevention program prior to their surgery. These prevention programs are often referred to as prehabilitation and combine strength and cardiovascular training with breathing exercises. Despite the obvious benefits, prehabilitation programs are not yet commonly applied outside of research settings as they carry considerable costs and required additional skilled personnel.

In response to the unmet need for a widely applicable, cost and personnel efficient prehabilitation program a home-based prehabilitation program has been designed. This prehabilitation allows patients to safely perform an individualised set of exercises without relying on a personal trainer or a training group. Efficiency and feasibility will be evaluated in this study.

The average age of hospital patients has steadily increased with the demographic change of Germany's ageing population. In 2014, more than 27 million people living in Germany were older than 60 years and more than one third of this group had to undergo surgery within that year.

A relevant proportion of this patient group has to be considered frail or pre-frail. Over a lifetime every individual experiences a physiological reduction of functional capacity across all organ systems resulting in frailty. Consequently, physical and psychological stress, such as a hospital stay and surgery cannot be readily compensated. Therefore, frailty is a highly predictive pre-operative risk factor for increased post-operative morbidly and mortality, prolonged hospital stay and loss of independence. Multiple studies have demonstrated post-operative outcome of frail patients can be drastically improved if these patients are identified prior to elective surgery and enrolled in a multimodal prehabilitation program. The core of prehabilitation is physical exercise next to nutritional and psychological support. The improvement of cardiovascular condition, ventilator capacity and muscle strength gained during prehabilitation resulted in a reduced incidence of complications including pneumonia, shorter hospital stays and improved quality of life. Yet despite these benefits prehabilitation is not yet widely available outside of clinical studies as they carry considerable costs and demand additional skilled personnel.

In order to provide prehabilitation to a larger group of patients, a pre-operative exercise program was developed, that can safely be followed by pre-frail and frail patients at home without the need of continuous instruction and supervision by a trainer or physiotherapist. Efficacy and feasibility will be evaluated in this study.

• Experimental: Prehabilitation
  Participants are scheduled for elective surgery and follow the home-based prehabilitation for 11-17 days
  Intervention: Behavioral: Unsupervised home-based physical prehabilitation
• Experimental: Prehabilitation + TAVI
  Study participants who will undergo a TAVI form a subgroup with a modified enrolment procedure and longer duration of the intervention. The prehabilitation period is extended to 30 days.
  Intervention: Behavioral: Unsupervised home-based physical prehabilitation
• No Intervention: Control
  Participants are initially evaluated for frailty prior to scheduled surgery but subsequently receive regular care without a prehabilitation program. All pre- and postsurgical evaluations will be identical to the prehabilitation group.
• No Intervention: Control+TAVI
  The subgroup of participants who undergo a TAVI will be compared to a group of patients who will have had the same procedure. Hence the control group will also receive a screening via phone but then receive regular care. Follow-up after surgery will be identical in all groups.

• Kim SW, Han HS, Jung HW, Kim KI, Hwang DW, Kang SB, Kim CH. Multidimensional frailty score for the prediction of postoperative mortality risk. JAMA Surg. 2014 Jul;149(7):633-40. doi: 10.1001/jamasurg.2014.241.
• Makary MA, Segev DL, Pronovost PJ, Syin D, Bandeen-Roche K, Patel P, Takenaga R, Devgan L, Holzmueller CG, Tian J, Fried LP. Frailty as a predictor of surgical outcomes in older patients. J Am Coll Surg. 2010 Jun;210(6):901-8. doi: 10.1016/j.jamcollsurg.2010.01.028. Epub 2010 Apr 28.
• Jadczak AD, Makwana N, Luscombe-Marsh N, Visvanathan R, Schultz TJ. Effectiveness of exercise interventions on physical function in community-dwelling frail older people: an umbrella review of systematic reviews. JBI Database System Rev Implement Rep. 2018 Mar;16(3):752-775. doi: 10.11124/JBISRIR-2017-003551.
• Boden I, Skinner EH, Browning L, Reeve J, Anderson L, Hill C, Robertson IK, Story D, Denehy L. Preoperative physiotherapy for the prevention of respiratory complications after upper abdominal surgery: pragmatic, double blinded, multicentre randomised controlled trial. BMJ. 2018 Jan 24;360:j5916. doi: 10.1136/bmj.j5916. Erratum in: BMJ. 2019 Apr 25;365:l1862.
• Beggs T, Sepehri A, Szwajcer A, Tangri N, Arora RC. Frailty and perioperative outcomes: a narrative review. Can J Anaesth. 2015 Feb;62(2):143-57. doi: 10.1007/s12630-014-0273-z. Epub 2014 Nov 25. Review.
• Rockwood K, Song X, MacKnight C, Bergman H, Hogan DB, McDowell I, Mitnitski A. A global clinical measure of fitness and frailty in elderly people. CMAJ. 2005 Aug 30;173(5):489-95.
• Stark PA, Myles PS, Burke JA. Development and psychometric evaluation of a postoperative quality of recovery score: the QoR-15. Anesthesiology. 2013 Jun;118(6):1332-40. doi: 10.1097/ALN.0b013e318289b84b.
• Jammer I, Wickboldt N, Sander M, Smith A, Schultz MJ, Pelosi P, Leva B, Rhodes A, Hoeft A, Walder B, Chew MS, Pearse RM; European Society of Anaesthesiology (ESA) and the European Society of Intensive Care Medicine (ESICM); European Society of Anaesthesiology; European Society of Intensive Care Medicine. Standards for definitions and use of outcome measures for clinical effectiveness research in perioperative medicine: European Perioperative Clinical Outcome (EPCO) definitions: a statement from the ESA-ESICM joint taskforce on perioperative outcome measures. Eur J Anaesthesiol. 2015 Feb;32(2):88-105. doi: 10.1097/EJA.0000000000000118.

Inclusion Criteria:

• pre-frail or frail according to (Longitudinale Urbane Cohorten Altersstudie) LUCAS-functional index
• scheduled for elective surgery
• planned ward admission for at least 24h after surgery

Exclusion Criteria:

• Refusal of participation
• Presentation less than 2 weeks prior to scheduled procedure
• Pre-existing pronounced immobility (wheelchair bound, paresis of both arms or both legs)
• Minor surgical interventions such as small excisions of superficial tissues, small interventions for haemorrhoids, curettage, gastroscopy