Stable Ischaemic Heart Disease / Chronic Coronary Syndrome

Stable Ischaemic Heart Disease (IHD) Care Protocol will be implemented from January 2025 – HSG GPs may refer to updates from AIC for details on the implementation of these protocols.

Background

Stable Ischaemic Heart Disease (IHD) includes 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 or stable symptomatic in whom IHD was previously diagnosed or detected at screening, and/or

2. Asymptomatic or 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. To prevent the onset of complications such as heart failure and atrial fibrillation.

Note on selected investigations in primary care:

1. Electrocardiogram (ECG)⁺

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

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

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

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

2. Chest X-ray

1. 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. Gradual increase physical activity under a physician's supervision.
4. Limiting alcohol intake – for good overall health.

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

Daily 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.

Table 1: Exercise Recommendations

	Aerobic	Resistance	Neuromotor / Balance	Flexibility
Frequency	5–7x week	2–3x week	2–3x week	2–3x week
Intensity	Moderate	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)

*For the special subpopulation of patients who are post-surgery and undergoing cardiac rehabilitation, exercise prescriptions should be done in consultation with the hospital in which the patient had undergone surgery.

3. Smoking Cessation

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

4. Education

1. IHD, its symptoms, disease progression and clinical management.
2. Actionable steps to take when red flags are recognised.

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

If initiated, maintain aspirin at 100 mg/day indefinitely, if not contraindicated. Consider clopidogrel (75 mg/day) if aspirin is contraindicated.
Do a baseline full blood count for patients on platelet therapy – check for anaemia and thrombocytopaenia.
Consider adding on proton pump inhibitor therapy for gastric protection.

2. Lipid Lowering Drugs

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).
Statins are the drug of first choice for both hypercholesterolaemia and mixed hyperlipidaemia.
Ezetimibe 10 mg may be added if LDL target is not achieved despite maximal tolerated doses of statins.

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

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

Diabetes mellitus and hypertension.
Heart failure, reduced ejection fraction or asymptomatic left ventricular systolic dysfunction.

ii) Angiotensin receptor blockers (ARBs) are suitable:

For patients who are intolerant of ACE-Is (especially those who develop a persistent cough).
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 Drugs

Sublingual nitroglycerin or nitroglycerin spray can be used for the immediate relief of angina.
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.
Trimetazidine may be prescribed if a patient is still having angina after maximum dose of other anti-anginal drugs. Such patients can still be managed in primary care as long as their symptoms are stable.

Influenza, Pneumococcal and COVID-19 Vaccinations

Ensure that influenza, pneumococcal and COVID-19 vaccinations are up to date. Please refer to the table on Recommended Care Components below for further details on vaccinations for patients with IHD.

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 <23 kg/m²(For Non-Asian population, keep body mass index <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	Two initial COVID-19 vaccine doses at an interval of eight weeks apart An additional dose in 2024, around one year (and not earlier than five months) after the last dose received, is recommended for all persons aged 60 years and above, medically vulnerable individuals (e.g. patients with heart conditions) and residents of aged care facilities.	As recommended in MOH Circular No. 12/2024 dated 29 February 2024

* More frequently if clinically indicated.

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 subsidy claims and 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)*

[COVID-19 Vaccination fields will be implemented in HSG-Compatible CMSes in Nov 2024]

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. When making claims for these medications, GPs will need to submit the quantities and selling prices for the drug product prescribed.

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

References

European Society of Cardiology – 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes.
NHGP CPG – Stable Ischaemic Heart Disease. January 2019.
Chronic Disease Management Programme – Handbook for Healthcare Professionals 2022