A 56-year-old woman is admitted for elective total knee replacement. She has severely limited mobility and surgery is expected to improve this dramatically.
She is known to have hypercholesterolaemia and hypertension. In addition to simvastatin and ramipril, she takes atenolol. In preparation for her surgery she is nil by mouth from midnight. She does not take any of her medications the following morning. Whilst waiting to transfer to surgery she develops chest pain, and an assessment by the ward doctor reveals that she has inferior ST depression on ECG. Subsequent serum troponin measurement is positive.
Which one of the following therapies do you recommend?
The risks of non-cardiac surgery within the next 6 weeks are significant and therefore, in the context of non-life-threatening orthopaedic symptoms, it should not proceed. Thrombolysis is not a treatment for non-ST elevation MI. Angiography within 48 hours is indicated. Choice of stent use is a balance of many factors, but based on the information given in the question, a bare metal stent seems to be most appropriate since it will enable the discontinuation of dual-antiplatelet therapy after 1 month if necessary. The safest option is not listed. That would be a full 12 months of dual-antiplatlet therapy following angioplasty with the most appropriate stent. However, it is clear that this patient has severely limiting symptoms which may need treatment within 12 months.
A 67-year-old woman with rheumatic mitral valve disease has been under observation for many years. She is asymptomatic. Her most recent investigation reveals a normal-sized and well-functioning left ventricle. The mitral valve area is calculated as 1.3 cm2 . There is mild MR. The left atrium appears dilated. There is moderate TR with a calculated PA pressure of 45 mmHg. She is due to undergo assessment for a total hip replacement.
What recommendation can you give to the anaesthetist?
Non-cardiac surgery can be performed in asymptomatic patients with significant MS (<1.5 cm2 ) and a systolic pulmonary arterial pressure <50mm Hg. Care needs to be taken to control heart rate and fluid balance. Development of atrial fibrillation can lead to serious deterioration. Open surgical repair or valvotomy is required for symptomatic patients or those with significant MS and elevated pulmonary artery pressures.
A 73-year-old man is referred for review in the cardiac outpatient clinic. He suffers from intermittent claudication and the vascular surgeon has recommended an aorto-bifemoral bypass graft. During the work-up it is discovered that he has an ejection systolic murmur and your opinion regarding operative fitness has been sought. In your consultation you discover that he has no symptoms of chest pain or shortness of breath, and has never had a syncopal episode. Clinically, he has aortic stenosis. An echocardiogram is arranged and demonstrates a peak gradient of 85 mmHg.
What is your recommendation regarding his fitness for the vascular surgery?
Aortic stenosis with a peak gradient of 85 mmHg is categorized as severe. Even without symptoms, valve replacement should be considered for high-risk non-cardiac surgery such as this vascular procedure. Balloon valvuloplasty may be an appropriate bridge to definitive treatment in the face of emergency non-cardiac surgery, but is not appropriate here. This patient will most likely have extensive arterial disease, and needs aggressive secondary prevention, but an operation should not be denied on these grounds.
You are asked to assess a patient prior to elective orthopaedic surgery.
Which one of the following factors merits further risk assessment?
Inability to climb two flights of stairs represents a functional capacity <4 METs and requires further risk assessment. Although the other risk factors are relevant, they are each only minor predictors of perioperative risk. Optimal medical therapy would be recommended in any case.
Which one of the following sets of findings in patients undergoing non-cardiac surgery is associated with an increase in long-term mortality?
Peri-operative small elevations in troponin levels have been shown to be prognostically significant in high-risk and intermediate risk groups. Even in patients with end-stage renal disease, a minor troponin rise correlates with a worse prognosis compared to those with undetectable values. Temporary worsening of renal function has also been shown to be associated with an increase in long-term mortality.
It is estimated that almost half of all high-risk patients undergoing non-cardiac surgery have frequent ventricular premature beats (VPBs) or non-sustained VT. There is no evidence that VPBs or non-sustained VTs alone are associated with a worse prognosis.