Stable chest pain

Cardiology

Stable chest pain is characterised by angina or angina-equivalent symptoms provoked reliably by physical or emotional stress.

AHA recommendation is that clinicians assess the pre-test probability of CAD based on age and symptoms in order to decide on further testing.

The darker green and orange squares above denote groups in which non-invasive testing is most beneficial (pre-test probability >15%).

Table of Contents

SCOT-HEART

CT coronary angiography in patients with suspected angina due to CAD
Lancet 2015. All patients referred from primary clinics to Cardiology for Ix
Standard care vs. Standard care + Calcium score and CTCA for patients referred to Cardiology clinic for investigation of chest pain
Primary endpoint – Certainty of diagnosis of angina secondary to CAD at 6 weeks
Clarified diagnosis, enabled targeted interventions and non-significant reduction of MI risk

At 6 weeks CTCA + coronary calcium score
- Increased certainty of coronary artery disease RR 2.56 and angina due to coronary artery disease RR 1.79
- Increased frequency of coronary artery disease RR 1.09 but reduced frequency of angina due to coronary artery disease RR 0.93
Diagnosis changed in CTCA group of coronary artery disease in 27% of participants vs. 1% of standard care group
Diagnosis changed in CTCA group of angina due to coronary artery disease in 23% vs 1% of standard care group

Changed in planned investigations in 15% of CTCA group vs. 1% of standard care group
Use of CTCA resulted in cancellation of 121 functional tests and 29 invasive coronary angiograms
CTCA associated with 94 further invasive coronary angiograms however
These changes resulted in changes in recommendations for preventative therapies (18% vs. 4%)

SCOT-HEART 5 years

SCOT-HEART 5 years

5-year rate of MI or death from CAD
- 2.3% vs. 3.9% standard care
- Rates of invasive coronary angiography and revascularization higher in CTCA group in first few months but equal at 5 years
  - May have driven reduced event rate overall however given earlier intervention
- More preventative therapies (statin/aspirin) in CTCA group vs. standard group (19% vs. 14%) as it was protocoled that positive CTCA was prescribed this vs. standard group positive stress tests not mandated to be started on medications

Outcomes of anatomical versus Functional testing for CAD
NEJM 2015
10 000 symptomatic patients to CTCA vs. functional testing
Functional testing
- 67% MPS, 22% stress echo, 10% stress ECG
- 30% of stress tests were pharmacological
Composite primary endpoint = Death, MI, Unstable angina or major complication
Secondary endpoints = Invasive angiography that did not show obstructive CAD and radiation exposure
No difference in positivity
Overall composite primary endpoint over 25 months
- 3.3% in CTA group vs. 3.0% in functional group
CTCA associated with fewer negative invasive caths (3.4% vs 4.3%)
CTCA associated with more caths overall within 90 days (12.2% vs. 8.1%)
CTCA associated with more revascularization (6.2 vs. 3.2%) but this was not a trial endpoint
Median cumulative radiation exposure per patient less in CTA group but overall radiation exposure higher in CTA group
Overall, test groups and ~53% risk of coronary artery disease pre-test (intermediate risk) but in the end had relatively low levels of disease
Suggests our pre-test risk calculations are relatively inaccurate and that there is scope for improved selection of patients for noninvasive testing

PROMISE Subgroup (Hoffman et al. Circulation 2017)

Prognostic value of noninvasive cardiovascular testing in patients with stable chest pain
Intermediate pre-test probability group functional vs. CTCA
Normal test result 33% CTCA vs 78% functional
Incidence rate of events 0.9% CTCA vs. 2.1% functional
In CTCA group, 54% of events were from non-obstructive CAD (<70% stenosis)
Determined discriminatory ability of CTCA to predict events was better than functional testing
Rates of non-obstructive disease on CTCA (not seen on functional imaging) predicts future MACE and probably indicates optimised medical care in line with COURAGE

Prospective natural history of coronary atherosclerosis
In patients with ACS, 50% of subsequent MACE were from non-culprit lesions
Non-culprit lesions were 32% +- 20% stenosed but more likely to have a plaque burdern >70%, minimal luminal area <4mm2 or classified on USS as thin-cap fibroadenomas
Raises the question of treating initial culprit lesion actually changes natural history of subsequent events

Optimal medical therapy or angiography +- PCI for positive CTCA/MPS
OMT based on COURAGE trial
All stable angina or anginal equivalent in patients over 40 with planned non-invasive imaging for diagnosis
Results pending

Does PCI alter outcomes in stable angina
2287 patients across 50 centres
Inclusion
- Stable CAD with >70% stenosis in at least one proximal epicardial coronary vessel AND
- Objective evidence of myocardial ischaemia
  - Positive stress
  - Stenosis >80% with classic angina on provocative testing
Exclusion
- Persistent Class IV angina despite medical therapy
- Markedly positive stress test (substantial ST depression or hypotension in Stage 1 of Bruce Protocol)
- Refractory heart failure
- Cardiogenic shock
- EF <30%
- Revascularisation in last 6 months
- Unsuitable coronary anatomy
Primary outcomes – Death and non-fatal MI over 2.5-7 years
Composite – Death, MI, stroke
No significant difference in either primary or secondary outcomes
Medical optimisation was undertaken by both groups
- Antiplatelet, long-acting metoprolol/amlodipine/ISMN, lisinopril/losartan, simvastatin +- ezetimibe and lifestyle counselling
Issues –
- 85% male patients
- Highly monitored optimal medical therapy
- Mostly bare metal stents

5 studies included found no significant reduction in death, non-fatal MI, unplanned revascularisation or angina

3.5 year follow-up interim results showed no difference in CV events between PCI/CABG group vs. conservative therapy for patients with stable IHD and moderate-severe angina

PCI vs. placebo for stable angina blinded RCT
Sham procedures
Stable angina
Exclusions
- >50% stenosis in another vessel
- ACS
- Left main CAD
- Severe LV impairment
Had 6 week medical optimisation prior
- Minimum weekly phone Cardiology Consult
- Home BP and pulse monitoring
- Aim for at least 2 anti-anginals per patients
6 week post-randomisation follow-up
No significant differences between groups in baseline physiology or uptake of medical therapy
No significant difference in:
- Exercise time
- Time to 1mm ST depression on exercise
- Angina
- Quality of life
Did not look at long-term symptom control, MI and/or mortality given only 6 week follow-up time frame
Microvascular pathology may explain anginal symptomatology
Needs external validation

Last Updated on December 24, 2021 by Andrew Crofton