Recent data are reshaping how angina is approached. Firstly, a large RCT (the ISCHEMIA study) re-iterated that we need not automatically proceed to revascularisation for stable angina, given no clear mortality benefit in doing so (after excluding left main stem or high-grade 3 vessel disease, and of course unstable angina). Secondly, a sham-controlled RCT (ORBITA) showed that aggressively up-titrating anti-anginals often obviates any additional symptomatic gains from a stent, at least in the short term.
Historically, angina was frequently treated by percutaneous intervention. Now, after excluding high-grade disease by CT Coronary Angiography (CTCA), chest pain clinics are more likely to recommend medical therapy in the first instance. Consequently, patients are more likely to need GP input in managing anti-anginals.
First-line anti-anginal therapy
All major guidelines recommend either beta-blockers (e.g. atenolol) or calcium-channel blockers (e.g. amlodipine). Many doctors assume beta-blockers are “cardio-protective”, but this is only the case if there is also reduced ejection fraction or recent heart attack. In fact, amlodipine may be a marginally more effective anti-anginal.
One way of choosing is to look at the heart-rate (atenolol first if fast) and blood pressure (amlodipine first if high). Combining both is the optimal treatment if one drug isn’t sufficient; up-titrate to the maximally tolerated dose and review response after 2-4 weeks. As needed sub-lingual GTN should also be prescribed.
Beta-blockers are well-tolerated, but side effects can include erectile dysfunction, claudication, hyperglycaemia, worsening psoriasis, and bronchospasm. Concern in COPD is generally unwarranted, however. Amlodipine can cause ankle-swelling, especially at higher doses.
Many turn, next, to long-acting oral nitrates, but other options are non-dihydropyridine CCBs (verapamil and diltiazem), nicorandil, and ivabradine. Bradycardia may preclude many of these, but nitrates and nicorandil are OK. Hypotension can also be tricky – ivabradine is an option but there is some concern about potential increased risk of MI and AF. Many doctors are unaware that allopurinol is an effective anti-anginal – a great option if both bradycardia and hypotension are present. Ranolazine is also widely used in Europe in this setting; not currently authorised in Australia but a TGA application is apparently imminent.
Avoid adding verapamil to beta-blockers (risk of heart-block), and warn about constipation. Nicorandil has little additional benefit if already receiving long-acting nitrates, and watch for rectal/oral ulceration. GTN patches are useful if GI malabsorption, and pre-medicating with sublingual GTN prior to exercise is surprisingly effective.
Timing of specialist advice
Unstable/crescendo symptoms will often prompt invasive management, and ongoing angina despite two drugs at a good dose warrants further assessment. In parallel, it is worth checking for anaemia, hypoxia, fast AF and thyrotoxicosis as unrecognised precipitants. Finally, statins and aspirin remain your patient’s main defence against MI.
Western Radiology is the largest community-based provider of CTCA in Perth, with branches across the metropolitan area. Our reporting cardiologists understand how important it is to provide clinical context to the report, ensuring you are best supported in managing your patient amidst an ever-shifting landscape of evidence-base and technology.
About the Author
Dr Adil Rajwani leads the CTCA and CMR service at Western Radiology, and the echo service at Royal Perth Hospital. He has a particular interest in CMR, and is one of the few cardiologists in WA to hold Level III accreditation by the Society for Cardiovascular Magnetic Resonance (SCMR).