38. Hypertension + IHD Flashcards
You are presented with an 80-year-old woman with hypertension,
diabetes mellitus and a touch of indigestion on climbing stairs.
Describe her pre-operative assessment for cataract surgery
Hypertension and diabetes are risk factors for ischaemic heart disease and the ‘indigestion’ on exertion may reflect undiagnosed angina.
A history of similar pains at rest or associated with other precipitants should be sought
Other features should be looked for in the history pointing to end-organ
damage such as orthopnoea, SOBOE or ankle swelling from ventricular
failure, renal disease or CVAs.
An assessment of exercise tolerance should be made, and if all she can
manage is a flight of stairs before getting angina, this warrants further
investigation as it is a predictor of mortality.
Describe her pre-operative assessment for cataract surgery
General
Control of the diabetes and hypertension may be evident from the notes, the GP’s letters or from the patient.
A medication history is important with regard to the diabetes and hypertension.
Other routine enquiries such as previous anaesthetics, last meal and reflux, airway assessment and an explanation of the procedure are, of course,
mandatory.
If you are concerned about her having IHD,
how would you investigate her?
Clinical assessment may reveal evidence of ventricular failure or peripheral vascular disease, for example, and help guide your assessment.
Simple tests such as the ECG can provide evidence of previous infarcts,
ischaemia, ventricular hypertrophy and the state of the conducting system.
CXR can assess the cardiac size and show evidence of LVF with lung
congestion.
Simple tests for end-organ damage include measurement of urea and
electrolytes and dipstick urine analysis. A lipid profile should be checked
An echocardiogram is useful if there is a history or clinical findings
suggestive of failure or of valvular heart disease to quantify the resting
function.
Dynamic assessment can be difficult in this group as mobility may be a
problem, but the simplest test is an exercise ECG which may prove
diagnostic as her pain seems to be brought on with minimal effort.
More formal dynamic functional testing may be appropriate as may
coronary angiography if her first-line tests show ischaemia.
She may also have a GI cause for her pain and, after excluding a cardiac
cause, USS of the abdomen or endoscopy may be necessary.
How would you assess control of her diabetes?
Motivated patients often keep records of their blood sugars and isolated BMs
can often be found in the medical records.
Hba1c is the commonest method of assessing control over about the
previous 6 weeks.
An Hba1c of 7% represents an average blood sugar of 8.3 mmol/l during
this time.
Good control is usually considered to be a value less than 7%.
With regard to control of her blood pressure, what drugs is she likely
to be on?
There are various classes of drugs used to treat hypertension:
ACE inhibitors are particularly useful in the diabetic as they can delay
progression of renovascular disease and protect against left ventricular
dysfunction.
Angiotensin II antagonists may be used if there is intolerance to ACEIs.
Thiazide diuretics are advocated as first-line therapy for isolated
hypertension and in the treatment of heart failure, particularly in the
elderly.
B-blockers can be used, particularly if there is associated ischaemic heart
disease but these should be used with caution in diabetics.
Alpha-blockers are used to treat hypertension, but they can cause
hypotension in the elderly.
Calcium channel blockers are appropriate especially if there is associated
ischaemic heart disease.
Her BP is 190/105 mmHg after three measurements both at pre-op
assessment and today. What would you do?
She has poorly controlled hypertension.
Assess what investigations and treatment she has received so far along with compliance with her current drug regimen.
‘White coat’ hypertension is a possibility and blood pressures from the
primary care physician may be available.
As she is having non-urgent surgery, her operation should be postponed
while her blood pressure is controlled and her cardiac symptoms
investigated.
What are the risks in anaesthetising her?
The biggest risks are of peri-operative cardiac events.
The commonest problems are:
Haemodynamic instability
(particularly profound hypotension on induction)
Myocardial ischaemia
Cardiac arrhythmias.
Hypertension
Isolated hypertension itself, with no evidence of end-organ damage, is
probably not directly linked to an increase in peri-operative morbidity
and mortality.
Hypertension though can be associated with cardiovascular, renal,
endocrine and cerebrovascular disease, which may be underlying or as
a consequence of the hypertension.
Careful pre-operative assessment should identify these patients and
they should be investigated further and treated as appropriate.
Describe the control of blood pressure in this lady, both in the immediate
and long term.
Her blood pressure is not dangerously elevated and so I would discuss this with her primary care physician and leave the choice of drug to them.
In the elderly, small doses of short-acting drugs are generally best to start
with and depending on her current therapy, the addition of a thiazide
diuretic, calcium channel blocker or ACE inhibitor may be appropriate.
Causes of secondary hypertension (which is usually endocrine or renal in
origin) should always be excluded.
These may be indicated by history and examination, but usually occurs in
younger patients.
Obesity, salt intake, hypercholesterolaemia and diabetes should also be
addressed.
Acute control of severe hypertension can usually be gained by intravenous infusions of nitrates or b-blockers, including labetalol or calcium channel blockers such as nifedipine.
A cardiologist should be involved.
Oral therapy with B-blockers, ACE inhibitors and diuretics can usually be
started once the acute crisis is controlled.
If she comes back with her cardiovascular problems under control and
she is scheduled to have her cataract done under a local anaesthetic
block, how would you manage her diabetes peri-operatively?
The Royal College of Anaesthetists and The Royal College of Ophthalmologists
have produced guidance for the management of patients having cataract
surgery under local anaesthesia and these state that fasting is not required,
assuming that there are no anticipated peri-operative problems and that the patient is not going to have any sedation.
The patient should take their usual insulin or anti-hypoglycaemic tablets
and eat and drink as normal.
Diabetic patients should still be done early on the list to allow them the
maximum time to recover,
but the emphasis is on minimising disruption
both to their physiology and to their normal routine.
Regular BMs should be taken.
White coat hypertension
So-called white coat hypertension is relevant to anaesthetic practice and
can be defined as a persistently elevated clinic arterial pressure in
combination with a normal ambulatory arterial pressure. Values currently
accepted are a BP of 140/90 mm Hg or greater in the presence of an
average daytime reading of less than 135/85 mm Hg. (This can obviously
be difficult to measure.)
The majority of the studies in this area show a benign prognosis for
white coat hypertension. Data suggests that patients who present for
elective surgery with admission hypertension that then settles to
normotensive levels are probably at less risk of cardiovascular
complications than patients with sustained hypertension
