Stable Ischaemic Heart Disease / Chronic Coronary Syndrome

Updated to align with “Management of chronic coronary syndrome” ACE Clinical Guidance (ACG)
Added a new section on Frequently Asked Questions (FAQs) for GPs

Background

Stable Ischaemic Heart Disease (IHD) / Chronic Coronary Syndrome (CCS), encompasses six common clinical presentations, as illustrated in Figure 1 below. It most often results when coronary artery plaque develops and reduces the oxygen supply to the myocardium. Early intervention is required to prevent disease progression and cardiovascular events. This includes lifestyle modification and medical therapy as indicated.

Figure 1: Classification of Ischaemic Heart Disease¹

The focus of this Care Protocol is on the management of patients who are:

1. Asymptomatic and stable, symptomatic in whom IHD was previously diagnosed or detected at screening, and/or

2. Asymptomatic and stable, symptomatic and in the post revascularisation phase.

Clinical Approach

The goals of management of stable IHD are to manage cardiovascular risk factors to:

1. Reduce the incidence of first acute myocardial infarction in patients with screening-detected CAD.

2. Reduce the recurrence of myocardial infarctions, and

3. Prevent the onset of complications such as heart failure and atrial fibrillation.

Note on selected investigations in primary care:

1. Electrocardiogram (ECG)⁺

a. Recommended in all patients during, or after a history of chest pain

b. Recommended in higher risk patients who present with symptoms suggestive of a non-cardiac cause of chest pain at the physician's discretion.

c. Not recommended as screening for the prediction of coronary heart disease (CHD) events in asymptomatic adults at low risk of CHD events.

d. Not recommended as a routine test for asymptomatic stable IHD patients.

2. Chest X-ray

a. Recommended in patients with atypical presentation or suspicion of pulmonary disease, often with breathlessness, or reduced effort tolerance rather than chest pain.

⁺Patients with acute cardiac events may present with a normal ECG. In situations where there is a high index of suspicion for acute coronary syndrome (ACS), the patient may need to be urgently referred to the Emergency Department (ED) for serial ECGs, cardiac enzyme measurements, and closer monitoring.

Management

Non-Pharmacological Therapy

1. Dietary and Weight Management in Stable IHD

i) A diet rich in wholegrain foods, vegetables, fruit, legumes, nuts, fish, and unsaturated oils and low in saturated and trans-fat, refined sugar and cholesterol should be encouraged. Dietary intervention requires individualisation to meet the nutritional needs of patients with a variety of diseases or conditions.

ii) Dietary Advice

iii) If a patient has metabolic syndrome , further attention must be given to the following:

1. Weight management
2. Limit intake of sweet drinks and opt for unsweetened beverages.
3. Gradually increase physical activity under a physician's supervision.
4. Limit alcohol intake – for good overall health.
5. Advise patients to avoid situations that can induce psychosocial stress. Treat anxiety or depression with psychological and pharmacological interventions.

iv) In addition to these established nutrition parameters, patients interested in using further nutritional strategies may include soy products, nuts, and additional sources of omega-3 fatty acids in their eating plans.

2. Exercise

Regular physical activity and avoiding a sedentary lifestyle are important for cardiovascular health. Patients with stable IHD should be encouraged to exercise according to the principles in the Body Mass Index (BMI) Control Care Protocol, including to monitor their symptoms during exercise.

For the special subpopulation of patients who are in the post-surgery phase and undergoing cardiac rehabilitation, exercise prescriptions should be done in consultation with the hospital in which the patient had undergone surgery. Encourage patients who have attended cardiac rehabilitation programmes to continue the recommended physical activities after the programme has ended.

Exercise is contraindicated in certain patients and further assessment/advice from specialists may be needed.

Table 1: Exercise Recommendations

	Aerobic	Resistance	Neuromotor / Balance	Flexibility
Frequency	3–7x week	2–3x week	2–3x week	2–3x week
Intensity	Moderate ( ≥150 minutes per week) OR High (≥75 minutes per week) OR Equivalent combination of high and moderate intensity exercise	Mild to Moderate Volitional fatigue (aching on arms or legs) 1–3 Sets of 8–12 reps	Mild to Moderate	Within tolerance Do not overstretch
Type	Swimming Cycling Walking Running Aerobic Dancing	Major muscle groups Upper and lower limb, core muscles Free weights, exercise bands or own body weight	Taiji Yoga Qi Gong	General stretching for major muscle groups (upper, lower limb, neck and back muscles)
Time	10 mins or more for each session 150 mins/week		30–60 mins	5 x 20 secs
Progression	Increase duration before progression to intensity	Increase repetition before intensity (load)

3. Smoking Cessation

1. Strongly encourage patient and family to stop smoking and avoid passive smoking at every visit. Patients who do not currently smoke should not start. Provide counselling, pharmacological therapy and formal smoking cessation programmes as appropriate.

4. Patient Education

1. IHD, its symptoms, disease progression and clinical management.
2. Actionable steps to take when red flags are recognised.
3. Emphasise importance of adherence to medications and lifestyle interventions.

Pharmacological Therapy

While pharmacological therapy would usually have been initiated by the cardiologist, GPs' main role is to promote medication adherence and monitor for adverse effects.

1. Anti-Thrombotic Therapy

a. If initiated, maintain aspirin at 75 - 100 mg/day indefinitely, if not contraindicated. Clopidogrel (75 mg/day) can be considered as an alternative, even when aspirin is not contraindicated
b. Do a baseline full blood count for patients on anti-platelet therapy – check for anaemia and thrombocytopaenia.
c. Consider adding on proton pump inhibitor therapy for gastric protection.
d. For patients who are post PCI, ensure that they have a stipulated duration for dual antiplatelet therapy (DAPT) and clarify with referring cardiologist when necessary (e.g. if patient develops clinical conditions that warrant a shorter duration of therapy such as requiring imminent non-cardiac surgery).

2. Lipid Lowering Drugs

a. In patients with documented IHD, the recommended low density lipoprotein (LDL)-cholesterol goal level is <1.8 mmol/L (<1.4 mmol/L if post-ACS*).
b. Statins are the drug of first choice for both hypercholesterolaemia and mixed hyperlipidaemia. Continue statins indefinitely post-Acute Coronary Syndrome (ACS) as they stabilise plaques and reduce endothelial inflammation, beyond just LDL lowering.
c. Ezetimibe 10 mg may be added if LDL target is not achieved despite maximal tolerated doses of statins.
d. Consider addition of a PCSKI9 inhibitor if LDL >1.8 mmol/L despite maximum doses of statin and ezetimibe.

*These targets may not be feasible when LDL-C baseline levels are very high, even with the use of PCSK9i. For these patients, treatment should aim for a ≥50% reduction as the starting goal.

3. Renin-Angiotensin-Aldosterone System (RAAS) Blockers

a. Angiotensin-converting enzyme inhibitors (ACE-Is) are recommended in IHD patients with:

i) Diabetes mellitus and hypertension.
ii) Heart failure, reduced ejection fraction or asymptomatic left ventricular systolic dysfunction.
iii) Chronic Kidney Disease (CKD) (Refer to Chronic Kidney Disease Care Protocol for more details)

b. Angiotensin receptor blockers (ARBs) are suitable:

i) For patients who are intolerant of ACE-Is (especially those who develop a persistent cough).
ii) As a reasonable second line therapy for patients who are still hypertensive on ACE-I and diuretic therapy. There is no clear benefit for an ACE-I/ARB combination due to an increased risk of hyperkalaemia.

4. Anti-Ischaemic/ Anti-Anginal Drug

a. Immediate relief of angina symptoms:

i) Short acting nitrates

1. Sublingual nitroglycerin or nitroglycerin spray can be used for the immediate relief of angina.

b. Prevention of angina:

i) First line

1. Beta-blocker therapy is indicated in all patients with angina. In post-acute coronary syndrome patients, consider continuing it indefinitely. Before commencing beta blockers, it is important to exclude any contraindications. In general, aim to maintain a resting heart rate of 55–65 beats per minute.
2. Consider use of calcium channel blockers (CCB) if beta blockers are contraindicated.
3. Combination of non-dihydropyridine (DHP) CCB and beta blockers can be considered if initial treatment with beta blockers is not successful.

ii) Additional options

1. Long-acting nitrates, trimetazidine, ivabradine, ranolazine.
2. These may be added to a beta blocker and/or CCB if a patient is still having angina despite maximum doses. Such patients can still be managed in primary care as long as their symptoms are stable.

5. Oral Anticoagulation Agents (OAC)

a. Consider OAC monotherapy for patients with CCS and new onset AF, with no recent stents (within the last 12 months).

i) Stop antiplatelet therapy once OAC is initiated if there are no other indications for antiplatelet therapy (apart from CCS) due to increased bleeding risk.

b. Decision to initiate OAC should be guided by modified CHA₂DS₂VASc score and patient factors such as comorbidities and bleeding risk. OAC therapy is generally recommended for a CHA₂DS₂VASc score of ≥2.
c. Consult cardiologists regarding management for patients with new onset AF and stent within the last 12 months.

6. Management of Comorbidities associated with CCS

a. It is essential to optimise the management of comorbidities or associated conditions in patients with Stable IHD/CCS to reduce overall cardiovascular risk and complication.

Follow-Up

Patients with CCS on antithrombotic therapy should be followed up regularly for optimal management, even after their condition has stabilised and they are asymptomatic. Frequency of follow-up differs for each patient and is guided by the following (not exhaustive):

1. Severity of condition
2. Comorbidities and optimisation of risk factors
3. Changes in symptoms and functional capacity
4. Availability of resources

Components of follow-up:

1. Assess overall CV risk, especially in patients with comorbidities
2. Review any reported symptoms on exertion and at rest, and their impact on daily activities
3. Assess adherence to non-pharmacological advice and medications
4. Remind patients to keep up to date with vaccinations e.g. influenza vaccine
5. Assessments and (repeated) testing: perform as necessary depending on patient's symptoms, risk factors, and clinical judgement
6. Refer to tertiary care centers or specialists for further testing or collaborative care if necessary

Recommended Care Components

Table 2: Recommended Care Components

Recommended Care Components	Minimum Frequency*	Remarks
Blood Pressure Measurement	Twice a year
Weight and BMI Assessment	Twice a year	Keep BMI <23 kg/m²(For Non-Asian population, keep BMI <25 kg/m²)
Lipid Profile	Annually	Target LDL <1.8mmol/L as patients with IHD/CAD are in the “very high risk" group (target <1.4mmol/L if post-ACS)
Smoking Assessment	Annually for smokers; Once-off for non-smokers, unless there is a change in smoking habit	Assessment on smoking habits (estimated sticks/day; zero for non-or ex-smoker) and provision of smoking cessation management for smokers.
Diabetes Screening	Annually or once every three years, as clinically indicated	Screening should be carried out every three years for those with normal glucose tolerance, and annually for those with impaired fasting glycaemia (IFG) or impaired glucose tolerance (IGT). Refer to Diabetes Mellitus Care Protocol for diagnostic criteria.
Kidney Function Monitoring	Annually	Especially for patients on ACE-I. Serum Cr and estimated glomerular filtration rate (eGFR), and Urine Albumin-Creatinine (uACR) may be considered.
Influenza Vaccination	Annually or per season for: Patients with IHD aged 18 to 64 years; and All persons aged 65 years and older	As recommended under the National Adult Immunisation Schedule (NAIS)
Pneumococcal Vaccination	18 to 64 years of age: 1 dose of PPSV23 For patients with certain other medical conditions (e.g. immunocompromising conditions), PCV13 may be recommended before PPSV23. All persons aged 65 years of age and older: 1 dose of PCV13 1 dose of PPSV23 at an appropriate interval after PCV13 (and any previous PPSV23 dose)	For further details on dose schedule for PCV13 and PPSV23 based on age and medical conditions, please refer to: Care Protocol on Adult Vaccination; MOH Circular No. 23A/2017 dated 3 November 2017; MOH Circular No. 63/2016 dated 21 October 2016.
COVID-19 Vaccination	One initial COVID-19 dose for unvaccinated patients aged 5 years and above.^# An additional dose around one year (and not earlier than five months) after the last dose received for patients aged 6 months and above. ^# Two initial doses (eight weeks apart) for unvaccinated persons aged 6 months – 4 years	As recommended in MOH Circular No. 80/2024 dated 25 October 2024, for all persons aged 60 years and older, medically vulnerable individuals (e.g. patients with heart conditions) and residents of aged care facilities.

* More frequently if clinically indicated, except for vaccination.

Consideration for Specialist Referral

Specialist Review Recommended

Emergency or urgent treatment indicated, e.g., unstable angina, myocardial infarction (MI), and acute decompensated heart failure. Please convey urgently to emergency department (ED) by ambulance.
Suboptimal control of IHD risk factors despite lifestyle modification and optimised medical therapy, e.g., lipids, blood pressure (BP), and diabetes.

Consider Collaborative Care or Anchoring Care with Primary Care Physician

Stable IHD, e.g., stable angina, history of MI but otherwise stable condition.

Data Submission

The following data fields should be documented in general practitioners (GPs)' case notes as part of good clinical practice for all patients enrolled to their practice. Submission of data fields marked with asterisks* is required for Healthier SG payments.

Diagnosis

Diagnosis*
CDMP Condition(s)*
Diagnosis Year

Blood Glucose

HbA1c(%) OR Fasting Plasma Glucose (FPG) (mmol/L or mg/dL)

[If the patient with stable IHD concurrently has DM OR Pre-DM OR is being screened for DM, please refer to the respective DM, Pre-DM and CVRA screening protocols for more information on whether HbA1c or FPG is tied to payments]

Date

Blood Pressure

Systolic BP (mmHg)*
Diastolic BP (mmHg)*
Date*

Lipid Profile

LDL-Cholesterol (mmol/L or mg/dL)*
HDL-Cholesterol (mmol/L or mg/dL)
Triglycerides (mmol/L or mg/dL)
Total Cholesterol (mmol/L or mg/dL)
Date*

Kidney Assessment

Serum creatinine (µmol/L)* OR estimated glomerular filtration rate (eGFR) (ml/min/1.73m²)*
Urine ACR (mg/mmol)* OR Urine PCR (mg/mmol)*
Date*

Weight

BMI (kg/m²), calculated from height*, weight*
Waist circumference (in cm; mandatory to fill if weight is not feasible. Otherwise, optional field to fill)*
Weight not feasible (if applicable)*
Date*

Smoking History

Smoking status (Never smoker, Ex-Smoker, Current smoker)*
Year started smoking (if smoker)
No. of sticks smoked/day (For never smoker or ex-smoker, input 0)*
Stage of change: (i) Pre-contemplation, (ii) Contemplation, (iii) Preparation (iv) Action, or (v) Maintenance
Fagerstrom Test Score – For patients who are prepared to quit and are actively participating in a structured smoking cessation counselling programme, GPs can consider administering the Fagerstrom test to determine degree of nicotine dependence
Date of Smoking Assessment

Vaccination

SDD code*
Date of Vaccination*
Due Date of Next Dose
I acknowledge that I have reviewed the results and care delivery provided, that the vaccinations done are clinically indicated as per MOH's prevailing guidelines
Vaccination Exception Condition(s) (if applicable)*
COVID-19 Vaccination Dose Type*
COVID-19 Vaccination Condition(s)*

Medical Therapy

I have reviewed that the patient is on anti-platelet or anticoagulation therapy, as clinically appropriate.
I have reviewed that the patient is on ACE inhibitors (ACE-i) or Angiotensin Receptor Blockers (ARB), as clinically appropriate.
I have reviewed that the patient is on a beta-blocker, as clinically appropriate.
Date

Financing

CHAS/PG/MG cardholders who are Healthier SG enrollees can opt to use the Healthier SG Chronic Tier at their enrolled clinics, which provides percentage-based subsidies for selected chronic medications sold within the stipulated price caps.

Details on the GP Annual Service Fee for enrollees with Stable IHD can be found in the Healthier SG Enrollment Programme Agreement.

References

1. European Society of Cardiology – 2024 ESC Guidelines for the diagnosis and management of chronic coronary syndromes.

2. NHGP CPG – Stable Ischaemic Heart Disease. January 2019.

3. Chronic Disease Management Programme – Handbook for Healthcare Professionals 2024

4. Agency for Care Effectiveness (ACE). Management of chronic coronary syndrome. ACE Clinical Guidance (ACG), Ministry of Health, Singapore. March 2025.

Frequently Asked Questions (FAQ)

(Restricted Access) Click here to download.

Answer to common questions asked by General Practitioners (GPs) on the clinical conditions