6th March 2024

Stable angina

Pathophysiology

Angina pectoris, or stable angina, is often the first warning symptom of underlying coronary artery disease. It occurs when there is an imbalance between the myocardial oxygen supply and the myocardial oxygen demand.  Build-up of fatty plaques within the wall of the coronary artery causes the artery to narrow. During times of increased myocardial oxygen demand, this narrowing or stenosis of the artery prevents adequate myocardial supply, leading to the symptoms of angina. There are several risk factors for developing coronary artery disease. Modifiable ones include smoking, diabetes, hypertension, hypercholesterolemia, and obesity. Unmodifiable risk factors include increasing age, male gender and family history. NICE defines typical anginal pain as (1) a constricting discomfort in the front of the chest or in the neck, shoulders, jaw or arms (2) that is precipitated by exertion and (3) relieved by GTN within about 5 minutes. The presence of two of the features previously mentioned is referred to as atypical anginal pain, whereas the presence of only one or none of the features is referred to as non-anginal chest pain. 

Investigations

First line investigations include ECG and CT coronary angiogram. If significant coronary artery disease is found on CTCA, stable angina can be confirmed. Second line investigations include non-invasive functional testing for myocardial ischaemia such as myocardial perfusion scan with SPECT, stress echocardiography, first pass contrast-enhanced MR perfusion or MR imaging for stress induced wall motion abnormalities. These investigations are used to look for reversible myocardial ischaemia. NICE recommends offering coronary angiography as a third line investigation when the results of all the above-mentioned non-invasive functional tests are inconclusive. 

Management

Monotherapy with a beta blocker or rate limiting calcium/non dihydropyridine channel blocker (verapamil, diltiazem) should be initiated and titrated to the maximum tolerated dose. If a beta blocker cannot be tolerated, consider switching to a calcium channel blocker and vice versa. If symptoms persist despite maximum monotherapy dose, a combination of beta blocker and a long acting dihydropyridine calcium channel blocker may be used.

Where a beta blocker or calcium channel blocker cannot be added and symptoms are not controlled on monotherapy, the following may be considered: 

• A long-acting nitrate – Isosorbide mononitrate
• Ivabradine 
• Nicorandil 
• Ranolazine 

If symptoms are not controlled on dual beta-blocker and calcium channel blocker therapy, then consider adding only one of the above-mentioned drugs while the patient awaits revascularisation (PCI or CABG). A GTN spray should be offered to everyone in order to abort anginal attacks. 

For secondary prevention of coronary vascular disease patients should receive aspirin 75mg daily; a statin and have blood pressure and diabetes optimised. In patients with angina and diabetes consider offering an ACE-inhibitor.

References 

• Recent-onset chest pain of suspected cardiac origin: assessment and diagnosis. CG95. Published 24 March 2010. Last updated 30 November 2016. Accessible at: https://www.nice.org.uk/guidance/cg95/chapter/Recommendations#people-presenting-with-stable-chest-pain 
• Stable angina management. CG126. Published 23 July 2011. Last updated 25 August 2016. Accessible at: https://www.nice.org.uk/guidance/cg126/chapter/1-Guidance#anti-anginal-drug-treatment