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Cardiac Transplantation REVIEW PAPER

A Review and Guidelines for Exercise Rehabilitation

BeuerLeg ELLis

Key Wonls Cardiac care, transplants, exercise.

SlJmm8V This paper reviews current literature concerning the physiological effects of cardiac transplantation and their impact upon exercise rehabilitation. The second part aims to outline the Papworth approach to rehabilitating these patients. Many reviews have outlined the problems, but very few suggest potential treatment. There is tremendous scope for physiotherapy intervention in the short- and long-term management of these patients.

Introduction Cardiac transplantation offers an increasingly successful treatment for patients in end-stage heart failure. Sophisticated donor and recipient screening and management have resulted in ever-improving survival rates,

Patients accepted for transplantation are gener- ally middle-aged with a history of deteriorating ventricular function as a result of severe ischaemic heart disease or dilated cardiomyopathy; thus severe physical debilitation is commonplace. This is a result of pre-operative congestive cardiac failure which causes poor cardiac ejection fractions, dyspnoea, reduced exercise tolerance, and fatigue. The dramatic variation between individual medical histories gives rise to a variety of physical and psychological problems. In general transplant recipients are capable of returning to full and potentially very active lives (Kavanagh et al, 1988).

With transplant recipients surviving longer the need to maximise quality of life and physical recovery is paramount. Anecdotal evidence suggests that physiotherapy intervention within the multidisciplinary rehabilitation of these patients helps to avoid the perpetuation of chronic physical debilitation and anxiety which may curtail return to an active life. ‘Pransplant rehabilitation is a challenging arena in which physiotherapists can integrate and exploit their knowledge of exercise rehabilitation.

The implications of transplantation for physio- therapists are many and varied. Several literature reviews have documented the physiological changes associated with cardiac transplantation ffivanagh, 1991; Keteyian et al, 1989; Niset et al, 1991; Banner, 1992; Shepherd, 1992; Squires, 1991). While a number of studies have assessed the training effect upon transplant patients several

months or years following transplantation (Degre et al, 1987; Kavanagh et al, 1988; Keteyian et al, 1991; Brubaker et al, 1993), an extensive literature review revealed little research concerned with the in-patient rehabilitation of these patients.

The majority of research has been undertaken in America and Canada where it appears that patients remain in the locality for a number of months after transplant. Because most UK transplant centres take patients from all Over Great Britain, exercise rehabilitation here must begin during the three- to five-week admission period and then be continued in the home community, dependent purely upon the motivation of the recipient. Physiotherapy intervention therefore must be effective in initiating a behavioural change to incorporate exercise into everyday life, if physical rehabilitation is to be maximised.

Physiological Changes Associated with Transplantation Cardiac transplantation involves the removal of the native heart and the anastamosis of a donor heart to the recipient atrium. The nature of the operation and the medication required to prevent rejection all have a profound effect upon the physiology of the heart and body (see table).

Physiological changes associated with heart tmnsplant8

At rest Resting tachycardia Reduced resting stroke volume Normal or low cardiac output Resting hypertension Raised pulmonary artery pressure Decreased left ventricular ejection fraction

On exercise Delayed heart rate increase at onset of exercise Delayed return to resting heart rate on completion of exercise Reduced stroke volume increase on exercise (40-50% normal) Reduced cardiac output Decreased lef! and right ventricular ejection fraction Increased left ventricular end diastolic pressure Reduced anaerobic threshold Reduced peak power output Decreased maximal oxygen uptake Slow oxygen uptake by periphery Increased exercise ventilatory equivalent for oxygen and

Increased pulmonary artery and right atrial pressures carbon dioxide

Catmu of Physidogical Change Denemation of the Traneplanted Heart Transplantation renders the new heart denervaM the remaining recipient atrium plays no part as impulses are unable to cross the suture line. Heart rate (HR) is therefore determined by the intrinsic rate of the donor sineatrial node which is released from vagal inhibition (Banner, 1992). The new relatively high HR of 90 to 110 beats per minute (de Mameffe et d, 1986) results in a smaller resting stmke volume (Kavanagh et al, 1986) and a reduced Mireaerva HR responses to increased activity are therefore dependent upon the initial increased venous return mediated by increased muscular and thoracic pumping. This causes up to a 20% increase in etroke volume during early exercise (Frank- Starling mechanism) m p e et all 1980). For prolonged or vigomw exembe increased heart rate and cardiac output are dependent upon c h n e tropic and inotropic responses to the &dating catecholamines (Yusef et all 1987). T h w cate- cholaminea take up to ten minutes to have full &ect and then up to 16 minutea to be broken down, hence the attenuated HR response and recovery times crusef et d, 1987; Kavanagh, 1991). peak heart rates appear to be lower than in age matched controls (de MarneBe et 4 1986) due to raiaed d i n g heart rates and i n c r e d rewnse to catecholaminea Stroke volume and cardiac output are ale0 both reduced at peak exercise (Kavanagh, 1988). Hmewr, these mimic results found in cardiac patients in the early stages after Surgery (Ehrman et UZ, 1989).

Normal HR and blood pressure (BPI responses to training are mediated uia adjustments in sympathetic and parasympathetic tone This cannot take place aRer transplantation due to denervation (Kavanagh et al, 1988).

Reduction in Myocardial Compliance walr syetolic blood pressure (Kavanagh et al, 1988) is d u d in the acute &ages as a result of: OMyoCadd changes aseociated with the man- agement d brain death in the donor (Niaet et d, 1991). 0 %ti- cardiac d m 4 due to iachaemic time d the donor argan, impaired lymphatic

and the aperative and reperfueion insults This d t a in a reduction in left ventricular ejection fraction and impaired diastolic filling (Stovin and English, 1987).

In the long tenn peak SJrStolic BP ie lowed as a d t d:

d long-term immunosuppreesion (Stmin d 4 1987) d t l c k g lqY0cardia.1 compliance

.The effects of rejection episodes leading to concentric narmwing of the small coronary -arteries resulting in silent (due to denervation) ischaemic damage. Accelerated atherosclerosis due to rejection episodes, steroid-induced hyperlipidaemia or cytomegaloviru is shown at five years after oper- ation by 40% of transplant patients (Mann, 1992).

Immunosuppression (Cyclosporin, Azathioprine Prednisolone) Cyclosporin is markedly nephrotoxic, causing tubular dysfunction which in turn causes increased sq9tolic and diastolic BP at rest (Stovin eta& 1987; Starling and Cody, 1990). Pulmonary Musion capacity is reduced owing to the effect of immunosuppression upon the lungs (Casan et aZ, 1987).

Steroids may induce myopathy and osteoporosis (Harber et al, 1985). Kavanagh ef aZ(1988) state that steroid administration in the immediate post- operative period exacerbates the lean tissue loss caused by pre-operative inactivity. Sambrook et a1 (1994) state that steroid administration in the early stages after transplantation accelerates osteoporotic changes.

Noradrenalin Elevated circulating noradrenalin levels and increased myocardial sensitivity to circulating catecholamines (Yusef ef al, 1987) cause increased ayetolic and diastolic blood pressure at rest; however on exercise the circulating catecholamines are insufEcient to increase myocardial contractility to the degree normally mediated by the sympathetic nervous system, hence the blunted peak heart rate response. Chronic high levels of circulating noradrenalin cause an essential down-regulation of cate- cholamine receptors, which may explain the blunted BP response to maximal exercise (Borrow et al, 1985).

Heart rate may continue to increase a short time into recovery and will be slow to return to normal (Kavanagh et al, 1988).

Cardiac Failupe Pre-operative congestive cardiac failure causes reduced vascular compliance resulting in hypertension (Starling and Cody, 1990); and may

slightly r a i d pulmonary artery pressure in some patiente miset et al, 1991).

Physical Debilitation Reduced anaerobic threshold, as a result of debilitation, precipitates fatigue. It is combined with a resultant increase in ventilation, above that

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anticipated in age-matched normals (Niset et al, 1988; Kavanagh et al, 1988) and age-matched general surgery patients (Ehrman et al, 1989). Oxygen consumption at ventilatory and anaerobic thresholds is substantially reduced, which may be a result of debilitation (unconditioned ventilatory and peripheral responses to increasing oxygen requirement) or reduced cardiac output.

Reduced aerobic capacity of exercising muscles is due to unconditioned musculature and the reduced cardiovascular response to exercise.

Lean tissue loss following major surgery is common and is exacerbated by steroid administration (Kavanagh et al, 1988). Because of low peak oxygen uptake, exercise is quickly halted .by fatigue. A vicious circle may then result of lean tissue loss, weakness and susceptibility to fatigue.

Strengthening of skeletal muscle through exercise may facilitate muscle perfusion and thus reduce afterload on the heart, while increasing arterio- venous oxygen difference and thus oxygen delivery for a given cardiac output (Niset et al, 1991).

Anxiety The pre-operative psycho-social adjustment to transplantation is complex and individual. Post- operative feelings of resurrection and dis- orientation are common. Patients may often oscillate between euphoria and depression, and exhibit difficulty in concentrating and bouts of irritability. The cause of this is unknown, but it may be due to the prolonged anaesthesia, medication side-effects, or most likely simple psychological adjustment (Squires, 1991; Wallwork and Caine, 1985).

Poor exercise test and peak power output tests in patients following cardiac transplantation for

stated levels of perceived exertion may often be a result of debilitation and anxiety.

With exercise training, transplant recipients exhibit similar training effects as those with innervated hearts:

0 Higher peak heart rates. @Reduced resting systolic and diastolic blood pressure. @Reduced peak diastolic blood pressure due to reduced afterload. @Increased power input.

Later onset of anaerobiosis. @Reduced perception of effort.

Increased lean tissue mass. Increased peak oxygen uptake. Increased feelings of well-being and reductions

in anxiety and depression.

Spontaneous Recovery Without randomly allocated controlled studies the question of spontaneous or intervention mediated recovery can never be accurately answered. Spontaneous recovery is reputed to occur within the first six weeks following transplantation (Niset et al, 1991; Shepherd, 1992). Anecdotally the pre-operative debilitation, the psychological adjustment to increased activity and the fact that patients benefit greatly from exercise training at any stage following transplant, appear to support firmly the case of physiotherapy intervention following cardiac transplantation.

The remainder of this paper outlines the approach of Papworth Hospital, Cambridge, to the exercise rehabilitation of this client group.

Guidelines for Exercise Prescription Papworth Hospital transplants patients from all over Britain and so an out-patient programme is unrealistic. Rehabilitation after transplant must therefore be firmly established during the approximate three- to five-week hospital stay. In general a typical transplant patient will present with the following problems:

Active Problems 1. Potential respiratory problems secondary to anaesthesia, thoracic surgery, pain, immobility and immunosuppression.

2. Reduced exercise tolerance secondary to pre- operative debilitation and surgery.

3.Lack of knowledge concerning safe, effective exercise following cardiac transplantation.

Potential Problems 4.Anxiety due to psychological adjustment to transplantation.

5. Sternal incision takes six to 12 weeks to heal.

6. Lack of social support for increased activity.

7. Other existing medical/musculoskeletal problems.

8. Potential rejection episodes.

9. Reduced muscle plasticity, potential muscle injury or tendonitis as a result of deconditioning and steroid administration.

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matment Piam Respiratory Assessment Patients are usually extubated early on the first post-operative day. They are taught the active cycle of breathing technique and supported cough, and encouraged to repeat this cycle hourly. They are also encouraged to lie on alternate sides and seek adequate analgesia, to aid respiratory function. Chest phpiotherapy aims to prevent infection after anaesthetic, a problem compounded by the immunosupression. If set- are excessive, physiotherapy input is increased accordingly.

Mobilisation is started as soon as patients are c a r d i d a r l y stable, to aid respiratory function. It is essential that respiratory function is monitored throughout the hospital stay and that patients are advised about the signs of chest infedion and ita early treatment.

Rehabilitation Assuming a routine recovery, active upper and lower limbbed exerciees are begun on the first poet operative day, once patients are awake (either extubatad or intubated).

When the patients are cardiovaecularly stable (usually on the eecond day after operation) mobiliaation is started within their individual capacity. Gentle weight bearing exm5ees and static cycling are added and pmgresaed 88 appropriate. Exerciae intemity is purely symptom-timited, primarily by fatigue, and is progreseed by the therapiets ae appropriate.

Attention should be paid to maintaining full range shoulder movement following a sternal incision.

Once inotropic support is minimal or removed and the medical atafl are happy, patienta attend the gym twicedaily. There, exercise rehabilitation begins with a comprehensive generic warm-up (essential to stimulate catecholamine production) and mtchhg Warm-up should last for a t least ten minutea The exerciee component cowista of either aerobic circult training (with each patient exercieing at an individual level within the group) or progressive aerobic work using the treadmill, bike or walking in the grounda The emphasis is placed upon &up cohesion and support, eqjoyment, education and noncompetitive peraonal -achievement.

Patient8 are encouraged to work between 12- 16 on the Borg scale of perceived exertion (Borg, 1982) or within their physical limitations. comprehensive c o o l d m and stretching is vital after exercise, to enable catecholamine breakdown and to facilitate the development of suppleness. Cooldown should alao laat about ten minutes.

Once discharged to the half-way house, patients are encouraged to take increased responsibility for their rehabilitation. They are encouraged to keep a diary of their exercise participation and are loaned pedometers to help quantify their activity. Physiotherapy supewision continues three days a week.

Prior to discharge, realistic personal goals are agreed between patients and physiotherapists. Letters are issued to enable the patients to approach a community health and fitness professional safely and confidently, or in isolated cases a referral is made to the btient's local physiotherapy service for continued rehabilitation. Advice is given about abstaining fmm resisted upper limb work for the initial six- to 12-week period of sternal healing. The major part of discharge advice is to motivate and support the patienta to continue their exercises once at home.

Education Patients are supplied with a detailed educational package (the Papworth Programme) outlining the need to make a lifestyle change incorporating exerciee into daily life. b t r a n s p l a n t risk factors for IHD remain and are exacerbated by the immunosuppressive medication - exercise has been well shown to ameliorate these risk factors. This teaching is gradually reinforced throughout the rehabilitation process.

Clienta require individual attention and motiv- ation.if'behavioural change is to occur and be sus- tained. It is also helpful to promote discussion among transplant patients to motivate and support this lifestyle change.

Relapse prevention strategies are an essential pait of education. Patients need to be prepared for relapse and educated on how to reinstate exercise programmes. In the event of rejection they should reduce or cease exercise - depending upon the severity of the rejection. Patients should also be made aware that accelerated coronary artery disease (which occu1'8 because of repeated rejection) will no longer present as angina, thus progressive increasinq ahoi-tness of breath in the absence of rejection should always be medically investigated.

If patients are to adhere to any exercise prog- ramme, it must be appealing, convenient, involve friends or family, and be self-motivated. The initia1 home programme is initially geared towards waking and lower limb exercise. Durjng the six to 12 weeks of sternal healing there must be limitation of limb work, impact exercise, cycling, raquet and contact sports. Goal setting on an individual basis is an essential part of establishing the home programme and aiding compliance. Spouses are encouraged to exercise alongside the

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patients to help allay anxiety and to promote support which it is hoped will continue after discharge. Support is also given in establishing input from a qualified health and fitness professional.

Physiotherapists encountering such patients in the early stages after transplant can simply follow the exercise guidelines above Therapists requested to exercise patients several monthdyears after transplant need to be more aware of the problems of silent coronary occlusive diseaee. It is preferable to exercise test these patients or aeek the advice of the transplant centre before starting a vigorous programme of exercise Once sternal healing has occurred these patients are able to do virtually anything that they train for. Warm-up, stretches and oooldown remain an essential part of training. The best means of rating intensity of effort is via the Borg scale of perceived exertion. The ultimate aim is that patients will adhere to the American College of Sports Medicine (ACSM) (1990) guidelines which state that in order to gain any beneficial effects from exercise participation, aerobic exercise needs to be undertaken at least three times a week for 20 to 30 minutes. Thus patients will derive health benefits from their exercise and will be actively ameliorating existing risk factors for coronary artery disease

The ACSM (1993) guidelines streseed the beadits of a basic increase in daily activity, ie bouts of aerobic exercise totalling 30 minutes each day. Although this is w f d as a prelude to increased activity, these patients, who have a history daften severe debilitation, frequently require more formal training. Yet some patients will never want to exercise, regardless of its preaentation. Thus the ACSM guidelines (1993) are useful in an attempt to encourage these patients to undertaken some exercise.

Conclusion In the long term, cardiac transplant patients have the potential to respond well to exercise training. Indeed it is essential if their recovery is to be maximised. Transplant patients running marathons or competing in the transplant games are, sadly, the exceptions. It is difficult to persuade people to increase their activity levels if they previously did not enjoy exercise or were physically limited.

The clienta require the information and positive experience to enable them to make informed behavioural changes for life, not merely for the duration of their hospital stay to appease the medical staff. The dedicated multidisciplinary rehabilitation team offers an impatient' form of cardiac rehabilitation, followed by an informal

support and continual information service as long as the patients live.

If all that the therapists achieve is an increase in patients' basic levels of activity, then, according to the ACSM guidelines (1993) their clients will derive some health benefits from this activity and add life to their years and perhaps even add years to their lives.

Author and Addmss Ibr Corrsspondenor, B a w i e y U l i s B S c M C S P w a s a s e n k w ~ . atpapworth Hospital, Cambridge. This artide is a prelude to a re88ardl &dy undenakenaspartdanMScdegreemureealtheCityUniversny, London. Miss Ellis is now working d the Royal London Hospital, Whitechapel. London El 16&

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Abstract of Higher Degree Thesis

Artificial Neural Networks and Other Approaches to the Classification of Common Patterns of Human Movement

Thia thesie aime to apply neural networka in the clamification of human patterm ah mooememt and to cumpam the amunq d thie techniqua with existing methOde(amvEmb 'onal statbtica and diaieal aeeesament). Three difkent axamplea of human movement and one a € p o & m rn ehoeen faa study and a varietp of bioandudd param&ers ueed to deacrib them. The temporal panunetere of gait pat tar^, related to apead dwalking and walking with qlintad knee *r weighted ~ r r e r e ~ T b e ~ d i 6 p ~ t d b O t h h i p e andlursecr- msss\ned dming gohg upor d m &pa

Ocfive difFenmt heighk Merent atanding poatutes were studied by measuring the disposition of body landmarks associated with imagined moods of human mbjecta Finally, changes of the sit-stand-sit manoeuvre due to chronic low back pain, expressed as joint movement and forces exerted on the ground, were recorded. Patterne were c l d i e d by neural networks, linear diecriminant analysis and, in the case of sit-stand patterns, by qualified clinicians. By altering the number of variables to discriminate between patterns, benefits of the a h classifiem were identified. The SUCC~BB in classification of the measured patterns by neural netmrb was found to have an accuracy a t least as high as that of linear discriminant analysis. A neural network is a ueeful tool for the discrimination of pattern of human movements; its main advantage is the ability to deal with a large number OfpRdiCtor variablea A swcesfd trained and tested neural network can easily be eet up in a computer and, on the evidence presented, could be used to help clinicians diagnose or assess pathological patterns of movement.