Load max
194 Watt
VO2 max
20 ml/min/kg
78 % pred
HR max
102 bpm
62 % pred
RER max
1.21
VE max
94 L/min
110 % pred
VE/VCO2 slope
42
πO2
21.2 ml
107 % pred
FEV1
2.18 L
55 % pred
FVC
3.02 L
60 % pred
Tiffeneau index
58 %
When interpreting the CPET results, we can conclude that it was a maximal exercise test (RER max, 1.21; HR max, 62 % pred; VR = VE max/MVV = 108 %) with ventilatory, rather than cardiovascular limitation and a reduced aerobic capacity (VO2 max, 78 % pred).
Cardiovascular parameters confirmed a normal blood pressure evolution during the CPET (not shown), a normal oxygen pulse and therapy-induced chronotropic incompetence. Ventilatory parameters revealed a mixed restrictive-obstructive lung function, an abnormally elevated VE/VCO2 slope and ventilatory exercise test limitation.
Based on these findings there was a high suspicion for a pleural effusion, which was later confirmed by RxTx (Fig. 9.1).
Fig. 9.1
Chest X-ray illustrating evident blunting of the left costodiaphragmatic sinus, typical for a pleural effusion
Question
What can be done in the rehabilitation setting?
Diagnosis: Heightened suspicion for common complications is needed in the first weeks of ambulatory rehabilitation. Clinical examination in patients complaining of persistent dyspnoea or showing a lack of normal progression in the exercise load will easily exclude significant pleural effusion, severe paralysis of a haemidiaphragm or obstructive lung disease. An ergospirometry performed in the first weeks after the start of ambulatory rehabilitation will very often show 30–40 % reduction in the maximal tidal volume during exercise, but this tends to normalise during the program. A control ergospirometry in patients showing lack of progress will allow to differentiate between pulmonary and other causes. Further examinations can be done as needed (Rx Thorax, pleurocentesis, echocardiography, pulmonary function tests EMG of the phrenic nerve).
Rehabilitative therapy: It is not yet well known which physiotherapy techniques significantly influence the natural course of the pulmonary function after sternotomy [13, 14]. Most pleural effusions tend to disappear spontaneously or after a short course of anti-inflammatory drugs; in some cases, recurrent pleurocenteses or even pleurodesis is necessary. Hemidiaphragm paralysis due to phrenic nerve injury recovers spontaneously in 70–90 % of patients [15]. In severe cases, surgical intervention with plicage of the diaphragm is proposed [15]. Preoperative inspiratory muscle training [3, 4] can be a good technique to reduce the risk of postoperative pulmonary complications in patients with a compromised pulmonary function. If there is a place for postoperative respiratory muscle training remains to be determined. In some cases of reduced pulmonary function due to persistent respiration-dependent pain, a consultation with an osteopath can be of help to some patients [16].
Case (Part 3)
Which are the other rehabilitation problems that need attention in the first weeks after the start of the rehab program in this patient?
- 1.
Sternal wound healing: Externally, the wounds seem to heal well, but the sensation of movement at the sternal level, especially when provoked by changing position in bed, could point to incomplete healing of the bone. Crepitations felt during palpation next to the sternal wound are a clinical sign suggesting delayed healing. Delayed healing of the sternum is more frequent in patients after bilateral mammary artery operations and diabetics. In cases where sternal instability is suspected, all (asymmetrical) exercises with the upper limbs should be avoided until complete healing. In some cases, some instability persists; in severe cases, a refixation can be planned. The pain between the shoulder blades are a typical complication of sternotomy: the costovertebral joints are stressed importantly, with local bleeding, partial dislocation and an inflammatory process as a consequence of the opening of the chest during the operation. Painkillers may be required to allow the patient to sleep normally in the first weeks. Studies in our lab have shown that after a classical rehabilitation programme, some pain and reduced mobility persist in up to one third of the patients even 15 months after the operation. This may be related to the presence of a pleural drain and/or the exposure of the internal mammary artery. Up to now, it is not known which is the optimal therapy for these low-grade persistent pain problems: mobilisation exercises may have a place in the treatment, but definitive studies are lacking. In our rehabilitation centre, patients with persistent thoracic cage or spine problems are referred for advice by an osteopath.
- 2.
Heart rate: The heart rate suggests recurrence of atrial fibrillation (AF), which is very common after cardiac surgery [17, 18]. Up to 60 % of patients experience an often self-limiting episode of AF in the first days after operation, but during the ambulatory rehabilitation, it is much less frequent. Patients presenting in the rehabilitation unit with AF should be treated by anticoagulation and antiarrhythmic drugs or cardioversion. The rehabilitation setting is a very good place to detect these recurrences. Some categories of patients are more prone to recurrences and need to be checked regularly: mitral valve operations, COPD, obese patients, reduced systolic function, elderly patients, patients not treated with beta-blockers, etc.
- 3.
Obesity: After complicated surgery, it is not the ideal moment to immediately start a calorie-restricted diet. Also, more and more evidence is accumulating regarding the different roles of overweight and/or obesity in primary versus secondary prevention for cardiovascular disease (the so-called obesity paradigm) [19, 20]. In secondary prevention the optimum body weight is shifting to a higher BMI range, to appreciate the association of higher body weight and outcome in cardiovascular disease. Lifestyle recommendations for patients who are overweight/obese should be made, with more careful consideration of the often catabolic condition of chronic cardiovascular disease and may be more focused on encouraging exercise and a healthy diet that may not necessarily include caloric restriction.
- 4.
Swollen ankles: Swelling of the ankles is a frequent phenomenon after exposure of veins for bypass surgery. Normally, the swelling disappears spontaneously after 6–12 weeks, even without intervention. Diuretics are not advised, as they can cause disturbances of electrolytes and renal function and may reduce the blood pressure, which is often low in the first 4–6 weeks after CABG. Support stockings reduce traction on the scars in the legs and are advised to be used during daytime until swelling disappears
- 5.
Hypotension: Patients after coronary bypass surgery often show a reduced blood pressure in the first weeks after rehabilitation. This reduction in blood pressure is multifactorial (bed rest, reduced food and fluid intake, blood pressure-lowering treatment, etc.). This can give rise to orthostatic reactions if the preoperative antihypertensive therapy is not (temporarily) reduced. In most cases, the blood pressure returns to its preoperative value 6–8 weeks after surgery, and the antihypertensive therapy will therefore often be reduced in the beginning of the rehabilitation program, while increasing treatment is needed at the end of the programme. In the meantime, advice concerning low-salt food should be given.
- 6.
Postoperative peripheral neuropathies [21–23]: The majority of neuropathies occur as a consequence of entrapment or elongation of a part of the root of the plexus brachialis (nervus ulnaris) or of the peroneal nerve and are apparent only in the postoperative stage (often seen only in ambulatory rehabilitation):
- (a)
Brachial plexus palsy: With an incidence of 5 and 24 %, it is mainly caused by the positioning of the arm (or both arms) in abduction (90°) and external rotation (30°) during surgery [13, 16, 24]. This combination puts the plexus in a maximal stretch situation. The retraction of the sternum and possible fractures of the first rib are also described as causal factors [16]. The plexus stretch can be further accentuated by turning the head of the patient into the contralateral direction. Exposure of the internal mammary artery, necessitating a greater retraction of the chest wall, has also been mentioned as a causal factor. In most patients especially, the lower roots (giving rise to the ulnar nerve) are injured and general pain is the primary complaint. Medical assessment is by electromyographic evaluation of the brachial plexus region. The majority of the patients also need to be included in an extensive physiotherapeutical treatment. Nevertheless the functional recovery process of the injured nerve is often complete after an average convalescence period between 3 weeks and maximum 1 year.
- (b)
Peroneal nerve injury [24]: The prevalence of this postoperative nerve lesion is rare: literature sources mention an incidence of 0.30 % [13] up to 6 % [24]. In most cases the problem is attributed to excessive external rotation of the leg(s) and/or the hip(s) during surgery. Considering the superficial location of the peroneal nerve(s) compression around the head of the fibula can be expected. In most of the cases, the injury is unilateral (59 %) [13], and the patient experiences reduced dorsal flexion of the ankle as well as impairments of skin sensitivity and pain. Electromyographic evaluation is recommended, but as the first signs of nerve denervation are visible at earliest 10 up to 14 days after the first occurrence of the peripheral nerve lesion, the examination needs to be postponed to the third postoperative week. In spite of the fact that the prognosis of this problem is good in most cases, some cases with a long-term impairment of the nerve function are reported. For both neurological disorders, some comorbidity problems such as diabetes, older age, subnormal body weight and the duration of the operation can have a significant negative influence [13, 14, 16, 24].
- (a)
Case (Part 4)
The patient suffered from several postoperative problems. Are there novel treatment options that could prevent some of these?
Minimally invasive coronary artery bypass grafting has become an interesting alternative to conventional coronary artery bypass grafting [25–29], not necessitating the midline sternotomy. The endoscopic atraumatic coronary artery bypass (endo-ACAB) can be differentiated from the endoscopic coronary artery bypass grafting (endo-CABG) and the hybrid coronary revascularisation. In endo-ACAB, an off-pump bypass is created between the LIMA and LAD through multiple small holes (Fig. 9.2). In endo-CABG, an on-pump bypass is created between both the LIMA, RIMA and > 1 stenotic/occluded coronary arteries. Hybrid revascularisation combines minimally invasive coronary artery bypass surgery (of the LAD) and a percutaneous coronary intervention of a non-LAD lesion [30]. These novel treatment options have the advantage of reducing perioperative blood loss, postoperative pain, hospital admission duration and accelerating patient recovery and return to work [31].
Fig. 9.2
Endo-ACAB procedure
Theoretically these minimally invasive care strategies could be recommended for patients with an eligible coronary anatomy, who are considered too high risk for open cardiopulmonary bypass surgery via midline sternotomy, including those with a high risk of deep sternal wound infection (diabetes mellitus, morbid obesity), severely impaired left ventricular systolic function, chronic kidney disease, significant carotid or neurological disease, severe aortic calcification, prior sternotomy and lack of venous conduits [32].
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