Most patients can resume physical activity within a few days of percutaneous coronary intervention (PCI), and cardiac rehabilitation may commence within 2 weeks, unless obvious problems are evident.  

When prescribing exercise to patients following PCI, the following should be considered:

• Underlying cardiac pathology
• Type of PCI and the risk of restenosis
• Any complications associated with the procedure
• Discomfort at rest or on exertion at, or distal to, the site of peripheral artery cannulation
• Presence of angina symptoms at rest or on exertion
• The patient's compliance with anti-platelet medications.

Objective testing of exercise capacity may be contraindicated in some patients, such as those presenting with unstable angina and arrhythmia, at this time. It is important to check with the cardiologist or cardiac surgeon on the safety of attempting objective assessment of exercise capacity and consider ECG-monitoring throughout and after the assessment.

Self-paced tests such as the 6-minute walk test (6MWT) and the 6-minute bike test (6MBT) may be preferable than externally paced tests, such as the incremental shuttle walk test (ISWT). Safety of the 6MWT in patients awaiting CABG has not been established and if there are concerns it may be substituted with a 2-minute walk test or a modified 6-minute walk assessment.

Note factors that may reduce exercise capacity such as anaemia, pain, deconditioning, fatigue, cardiac and respiratory function. 

If the patient is haemodynamically stable and there are no other contraindications, sitting out of bed and gentle ambulation should commence within the first 24 hours following surgery. All patients should undertake a progressed walking program throughout the inpatient stay.

ECG monitoring (e.g., via telemetry) is often continued for at least 4 days post procedure to monitor for bradycardia, AF or other changes in heart rhythm which may occur following CABG or combined CABG and valve procedures. Patients with AF, particularly with rapid ventricular response (>100 beats per minute) are at risk of haemodynamic compromise during exercise. Blood pressure should be measured prior to mobilising and the patient monitored for signs of hypotension, dizziness, and fatigue.

Intermittent or continuous peripheral oxygen saturation SpO₂ should be measured during exercise using a portable pulse oximeter. Supplemental oxygen should be strongly considered during exercise if resting oxygen saturation is below 92%, or if the SpO₂ drops by 5% or more during exercise. Note that accurate measures of SpO₂ may be difficult in patients with AF. Almost all patients experience respiratory dysfunction to varying degrees after cardiac surgery. Supplemental oxygen will often be needed during exercise in the first 48 to 72 hours.

Other considerations include the following:

• Instruct patients to "Keep Your Move in the Tube" See Resuming functional activity following median sternotomy surgery
• Walking aids can be used safely to progress mobilisation if warranted.  Patients should be encouraged to use equal and even pressure through both arms. A single walking stick can also be used for support if care is taken not to weight bear predominantly through one side.
• Some patients may be able to commence moderate intensity exercise using large muscle groups (such as walking or cycling) during the inpatient stay. Supervised moderate intensity walking (RPE 11-12 on the 6-20 scale) has been shown to be safe and effective for improving functional capacity and distance walked at hospital discharge.  Stationary cycling may provide an alternative for those unable to walk without an aid, provided the patient can mount and sit comfortably. Stationary bikes also allow ease of telemetry and blood pressure monitoring.
• Upper limb and thoracic (trunk) exercises has been reported to reduce post-sternotomy pain. For specific recommendations on thoracic and upper limb exercises that can be commenced during the acute post-operative phase and in the weeks following hospital discharge, see section on Prevention of musculoskeletal complications.

“Keep Your Move in the Tube” is a simple framework that guides patients to move safely following median sternotomy surgery. The concept encourages short lever arms during load-bearing upper limb movements to facilitate safe bed mobility, transfers, and activities of daily living during the recovery period. As demonstrated in the figure below, the green tube represents favourable movements whilst unfavourable movements are demonstrated by the red tube.

By moving within the green tube, there is minimal movement at the sternal bone edges so no other precautions or restrictions are needed.  Ideally this method should be taught and practiced pre-operatively.

Keep Your Move in the Tube

Image to follow

Reproduced with permission from Bayler Scott & White Health, USA

Infection or disruption of the wires connecting the surgically divided sternum may lead to sternal instability and subsequent sternal separation, pain, and excessive motion of the sternal edges. As sternal non-union may lead to mediastinitis or deep sternal wound infection, early detection and management are essential.

Risk factors for developing sternal instability following median sternotomy include:  large breasts, diabetes mellitus, obesity, bilateral internal mammary artery harvesting, reoperation procedures, increased blood product requirement, and excessive coughing.

Sternal stability assessment

Sternal instability can be diagnosed by real-time ultrasound or physical assessment of the sternum employing the Modified Sternal Instability Scale (SIS). The SIS is a reliable scale of sternal instability and prompts timely referral and management to the cardiac surgeon.

Clinical examination

Patients with sternal instability often describe a clicking, clunking sensation and pain with activities such as reaching, rolling over in bed and getting up out of a chair. Assessment post-surgery should note:

• Pain quality and location– intermittent/constant, dull/sharp, hot/cold, deep/superficial

• Feelings of instability or excessive motion – e.g., patient reports that their chest feels like it is going ‘fall open’
• Clicking, or clunking type sounds
• Activities that provoke symptoms of pain, clicking or crepitus
• Wound or scar status including the colour, sensitivity to temperature, discharge (serous or coloured), hypersensitivity, and presence of keloid scarring or adhesions.

Modified Sternal Instability Scale (SIS) assessment procedure:

Note the grade of sternal instability when palpating the sternum during movement (see table below for definitions of grades). Palpate the upper and lower regions of the sternum separately as the lower sternum is often more unstable than the upper region. Palpate between the sternal halves using the 2nd, 3rd, and 4th digits (as shown in the figure below) during the following movements:

• Shoulder flexion (unilaterally and/or bilaterally)
• Trunk lateral flexion and/or rotation
• Coughing and deep inspiration and expiration

Select the grade that corresponds with the findings of the physical examination.

Ideally, all patients should undergo a sternal stability assessment at 3 to 5 days post-surgery, at the commencement of cardiac rehabilitation (3 to 6 weeks post-surgery), and prior to commencing advanced upper limb stretches and resistance exercises.

Table: Grading of sternal stability on the modified Sternal Instability Scale

Figure: Physical assessment of sternal instability

Sternal Instability Management

Patients diagnosed with sternal instability should be monitored every 3 to 4 weeks. For those with a modified sternal instability scale grade 2 or 3, it is important to notify the medical practitioner to ensure timely medical management such as surgical re-wiring or management of infection.

Patients with sternal instability should continue to follow the “Keep Your Move in the Tube” method to ensure safe performance of transfers and daily tasks.

A medication review may be necessary for those with a dry, non-productive cough secondary to medications (e.g., ACE inhibitors) to minimise risk of sternal instability.

An external bracing system, such as in the figures below,  can provide an interim measure prior to surgical repair or to minimise pain and prevent the progression of sternal separation. Early in the post-operative period all women should be encouraged to wear a supportive bra (such as a sports bra or surgical bra) with wide straps and no underwire to minimise stress on the healing sternum and wound.

Figure: Example of external bracing (a. Qualibreath and b. Qualibra)

a.

b.

Reproduced with permission from HjorthHealth Pty Ltd, 2012

Cardiac rehabilitation, where available, should be recommended to patients following cardiac surgery, with exercise training prescribed using the principles of “Keep Your Move in the Tube.” Patients should be encouraged to participate in individually prescribed and progressed, moderate intensity endurance training, aiming for an intensity of 13 -14 on the 6-20 RPE scale.

Early resistance training is safe for patients following median sternotomy, and results in no increase in pain, adverse events or sternal complications. Early resistance training also appears to enhance cognitive recovery in these patients [#pengelly-j-royse-c-williams-g-et-al]. This is important because 40% of patients who present for cardiac surgery have mild cognitive impairment and are more susceptible to further decline and progression to dementia compared to the general population.

Following implantation of an implantable cardioverter defibrillator (ICD) or permanent pacemaker PPM), patients are encouraged to avoid elevating the arm above shoulder level for a period of time to prevent lead dislodgement. This time frame may vary depending on the cardiologist so clinicians should abide by their local protocols. Limited evidence is available regarding resistance training following device implantation.  However, overhead loaded activities such as shoulder presses, should generally be avoided to reduce the risk of “subclavian crush” (due to narrowing of the space between the clavicle and first rib), and ultimately lead fracture.

Patients with ICDs are at risk of receiving inappropriate shocks during exercise if the HR increases to the zone at which therapies are programmed. Therefore, exercise should be planned to maintain the HR at least 10-15 beats per minute below the threshold. Contact sports must be avoided; it is particularly important to remind young people of this.

Ventricular assist devices (VADs) are implanted to increase circulating blood flow for patients with very poor cardiac function. In Australia, VADs are used as a bridge to transplant and occasionally for destination therapy.  Exercise prescription for these patients is highly specialised and clinicians should have a thorough understanding of the physiology imposed by different devices, and the patient’s response to exercise Most VADs rely on adequate preload thus requiring patients to be well hydrated. Blood pressure is generally measured by doppler and should be within a defined range, determined by the medical team, to safely exercise.

Whilst VAD hardware (controllers, batteries, drive lines) may restrict certain activities, most activities can be modified to accommodate these. The exercise specialist should be familiar with the VAD alarm systems and their implications for exercise training, and should know what do in any given alarm situation. VAD parameters should generally be recorded before and after each exercise session. The medical team/VAD coordinator should be made aware of any alarms that are triggered during the exercise session and these should also be documented. In some circumstances, the VAD settings may require alteration, necessitating close liaison with the medical team/VAD coordinator. Patients with a VAD cannot swim for exercise.

Exercise training is essential to optimise functional ability and fitness prior to transplant surgery, and to accelerate recovery in the post-operative phase. The pre-transplant phase may require shorter duration activities and greater rest periods, as per guidelines for exercise in heart failure. Exercise training, particularly for the quadriceps muscle, also helps offset the effects of immunosuppressive medication (muscle atrophy, bone demineralisation, increased adiposity) and assists return to routine life following transplantation.

Exercise should be prescribed and progressed according to altered physiology (e.g. cardiac denervation), individual circumstances and clinical presentation (e.g. post-surgical complications, episodes of cardiac transplant rejection and infection risk) to enhance continued and prolonged adherence to exercise.