Diagnosing Coronary Disease in 2025

Objectives

  • Overview of diagnostic modalities available for chronic coronary disease.

  • Approach to choosing the optimal test.

  • Special cases, new technologies, and future directions.

Relevant Guidelines

  • European: 2024 Guidelines for the management of chronic coronary syndromes

  • American: 2023 Multimodality Appropriate Use Criteria for the Detection and Risk Assessment of Chronic Coronary Disease

  • Canadian: 2014 (Outdated)

Rationale

  • Recent fellowships in Stress Echo and Nuclear Cardiology (SPECT and PET)

  • PET is expanding in Canada

  • Recent advances in Stress Echo (expanded protocols), Nuclear (PET + myocardial blood flow), and Clinical (ANOCA/INOCA)

Assessing Risk

Assessment

  • Rule out ACS
  • Non-cardiac causes
  • Assess pre-test probability

History

  • New studies show women and men present with typical chest pain similarly
    • 2/3 of both men/women present with symptoms categorized as non-characteristic
  • Women with CAD:
    • Older, hypertensive, dyslipidemia, + family Hx
    • Lower risk calculated by risk scores
  • Asymptomatic: more often in DM2, elderly, severe disease
  • Typical vs Atypical
    • Typical can predict obstructive CAD but less predictive for microvascular disease and vasospasm

Baseline Tests

  • ECG
  • Risk factor blood work
    • CBC, Lytes, Creatinine, Glucose, A1C, Lipids, TSH
    • LP(a) [once in patient's life]
  • Transthoracic Echo

Lipoprotein (a)

  • LP(a)
  • Genetically inherited cholesterol
  • Stable over the course of a lifetime
  • Associated with increased risk of CVD
  • No current targeted drugs on market but in testing
  • If elevated - aggressively manage other RFs
  • Lower threshold to refer to Cardiology to risk stratify 

CCS +

LP(a)

Note: FRS 5% + and elevated LP(a) should consider statin

Notes

  • Modify risk % further if other strong RF (ie. FH or PAD) or other clinical data (ie. vascular calcium on imaging)

 

  • Old risk tables based solely on chest pain, not accurate

Low Risk

  • <5% Very Low Risk - Defer testing
  • 5-15% Low Risk
    • Calcium score
    • GXT
    • Non-coronary imaging
      • Aorta/Carotid US
      • CT Thorax
  • Help decide on statin

RF Score + Calcium Score

https://www.jacc.org/doi/10.1016/j.jcmg.2021.11.019

Intermediate

  • Risk >15%:
    1. Stress Echo
    2. SPECT or preferably PET
    3. Stress Cardiac MRI
    4. CT Coronary (risk >5%)
    5. GXT not recommended first line

 

 

Note: no straight to cath option

ANOCA/INOCA

Definitions

  • INOCA: ischemia without obstructive CAD

  • ANOCA: angina without obstructive CAD

  • MINOCA: myocardial infarction without obstructive CAD

  • Endotypes: vasospasm vs microvascular disease
    • Vasospasm can be diagnosed on cardiac monitoring or provocative testing on cath (if high suspicion)
    • Microvascular disease diagnosed on cath or non-invasive tests
  • Treatment
    • ASA if CAD
    • Statin
    • Anti-anginals

Stress Echo 2025

Traditional Stress Echo

  • Identification of regional wall motion abnormalities to identify obstructive coronary artery disease
    • Qualitatively assessed

 

  • Other prognostic parameters:
    • Exercise duration, BP response, ST-T changes and LV dilation (not reliably reported)

 

  • Functional test: thus does not diagnose non-obstructive atherosclerotic disease that can still cause events

Compared to Alternatives

  • Advantages
    • ​Inexpensive
    • No radiation
    • Portable
    • Exercise and non-exercise
    • Less environmental impact compared to MRI/SPECT

Compared to Alternatives

  • Disadvantages
    • Functional testing thus may not pick up non-obstructive clinical atherosclerosis that can cause future events
      • Compared to Coronary CT
    • WMA are later in the ischemic cascade (not capturing perfusion changes)
      • Compared to myocardial perfusion imaging
    • WMA based protocol less useful in evaluating INOCA (ischemia with no obstructive CAD)

Pelikka 2019

Rest

Post Exercise

LAD Ischemia

Why New Protocol?

  • Change in referral pattern leading to a dropping positivity rate (<10% in some studies)
    • Reduced predictive value

 

  • Traditional stress echo protocol does not capture other areas of vulnerability in a heterogeneous population beyond identifying obstructive CAD
    • ie. lung water, LV contractile reserve, coronary microcirculation and cardiac autonomic dysfunction

 

  • New parameters are able to be implemented in Echo Labs without new technologies/sofware

ABCDE-SE Protocol

A - Wall motion abnormalities, volumes*

B - B Lines

C - Left ventricular contractile reserve*

D - Coronary flow reserve

E - Heart rate reserve*

 

*do not require additional imaging based on current protocol

Example: CAD

Example: Microvascular Dx

Al-Mohaissan 2023

Study

European Heart Journal 2021

Ciampi et al.

Prognostic value of stress echocardiography assessed by the ABCDE protocol

Predictors of Mortality

  • Postive:
    • B-lines
    • Coronary flow velocity reserve
    • Heart rate reserve
    • ABCDE Score 3 or greater
  • Negative:
    • Regional Wall Motion Abnormalities
    • Left ventricular contractile reserve

 

  • The mortality rate was 0.4%/year for a normal SE compared with 2.7%/year when all SE steps were abnormal.

Stress Echo 2030

ABCDE + F (regurgitant flow) G (LVOT gradients) L (left atrial volume/function) P ( pulmonary and LV pressures) L (RV function)

Practical Summary

  • Patients are becoming more complex

 

  • Canadian health care focuses on tech that provides value
    • Stress Echo is a relatively inexpensive tool and we are currently not harnessing its full potential

 

  • Patients to consider extended stress echo protocols:
    • Angina/ischemia with normal coronories (LAD flow)
    • Unexplained dyspnea (Diastolic stress test with B-lines)
    • High risk patients - further risk stratify (ABCDE protocol)

Ultrasound Enhancing Agents (UEAs)

  • Stress echo is dependent on endocardial resolution and UEAs dramatically increases visualization

 

  • Lipid microbubbles (unrelated to CT/MRI contrast)

 

  • Contraindications:
    • Hypersensitivity reaction to previous UEA or PEG 

 

  • Practical Summary:​
    • Academic hospital labs use UEA for the majority of patients, but workflow allows ad hoc usage
    • Clinics need to plan time for contrast (if not ordered may not use)
    • Unless known excellent images, recommend order with contrast and if issue, clinic will not use it

Perfusion Imaging 2025

SPECT

  • Still the foundation of myocardial perfusion imaging
    • Relatively cheaper (compared to PET)
    • Readily available
    • Calcium assessment*

 

  • Significant advances in the technology
    • Digital SPECT (no longer UNCLEAR medicine)
      • Lower radiation
      • Multiple positions
      • Quicker scan times
      • Most non-hospital clinics use DSPECT

Radiation

ASNC Board Review Course

Average annual dose from natural background radiation in Canada is 1.8 mSv. A typical chest CT scan is 7 mSv.

Example

https://www.mdpi.com/2075-1729/13/9/1879

Cardiac PET

Why PET

  • Higher diagnostic accuracy
  • Consistent high image quality, independent of patient characteristics (ie. increased BMI)
  • Reduced study times
  • Lower radiation exposure
  • Myocardial blood flow quantification
  • Always calcium assessment

Why Not PET

  • More expensive
  • No exercise (currently, but will be possible soon)
  • Low accessibility (geography and radioisotope factors)

Myocardial Blood Flow

  • Absolute quantification of blood flow through the coronary arteries
    • Rather than perfusion imaging which is a relative assessment
  • Measure blood at rest, stress and calculate relative change (reserve)
  • Gives more confidence for obstructive CAD as there should be paired perfusion defect AND reduced blood flow
  • Allows diagnosis of other endotypes of coronary disease
    • Microvascular disease

Classic Examples

  • Obstructive CAD
    • Perfusion Defect
    • Decrease in blood flow (stress, reserve, and +/- rest)
    • Calcium on CT
    • Abnormal cath

 

  • Microvascular Disease
    • Normal/abnormal perfusion
    • Decrease in stress blood flow relative to rest
    • No calcium on CT
    • Normal cath

Example - Obstructive CAD

ASNC Board Review Course

Example - Normal Perfusion

ASNC Board Review Course

Practical Summary

  • PET is expensive and not readily accessible but is a very high quality diagnostic tool

 

  • Canada is fortunate as Cardiac PET is expanding across the country

 

  • Patients to consider Cardiac PET:
    • Angina/ischemia with normal coronories
    • Need to minimize radiation dose
    • Cardiovascular Implantable Electronic Device Infections
    • Query sarcoid
    • High-risk patients - further risk stratify 

Coronary CT

Why CT

  • Anatomic test
    • Even if non-obstructive, additional knowledge of atherosclerosis can guide risk factor treatment
  • Relatively quick acquisition
  • New protocols have relatively low radiation
  • Evidence in low risk patients and higher
  • Complementary test to functional imaging
  • Non-invasive

Why Not CT

  • Long wait times (up to one year unless private)
  • No functional assessment
  • IV contrast needed

Practical Summary

  • Patients to consider Cardiac CT:
    • Postive function tests (Stress Echo/Nuclear) 
      • Rule out Left Main/Multivessel Disease which has evidence to intervene regardless of symptoms
      • Assess for false positives

 

  • Patients NOT to consider Cardiac CT:
    • Patients who likely need intervention
      • High-risk stress tests
      • Symptoms despite GDMT
    • Long wait times not appropriate

Thank you

Questions?