Coronary artery disease pt.2 Flashcards
Basic testing in patients suspected of having CCS
Basic (first-line) testing in patients with suspected CAD includes (can be done on an outpatient basis):
- Standard laboratory biochemical testing
- A resting ECG, possible ambulatory ECG monitoring
- Resting echocardiography
- In selected patients, a chest X-ray
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What should laboratory testing include for patients suspected of having CCS?
- Full blood count (including haemoglobin)
- Creatinine measurement and estimation of renal function (eGFR)
- A lipid profile (including including total cholesterol, high density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides)
- Fasting plasma glucose and glycated haemoglobin (HbA1c) should be measured in every patient with suspected CAD. If both are inconclusive, an additional oral glucose tolerance test is recommended
- Assessment of thyroid function is recommended in case of clinical suspicion of thyroid disorders
- If there is a clinical suspicion of CAD instability or ACS, biochemical markers of myocardial injury—such as troponin T or troponin I— should be measured, preferably using high-sensitivity assays
- It may also be reasonable to measure the uric acid level, as hyperuricemia is a frequent comorbid condition and may also affect renal function (not a recommendation but opinion)
Why is knowledge of glucose metabolism important in patients suspected of having CCS?
Important because of the well-recognized association between diabetes and adverse cardiovascular outcome
ECG recommendations in patients suspected of having CCS
- A resting 12 lead ECG is recommended in all patients with chest pain without an obvious non-cardiac cause
- A resting 12 lead ECG is recommended in all patients during or immediately after
an episode of angina suspected to be indicative of clinical instability of CAD
Typical initial ECG findings in patients suspected of having CAD
Two scenarios of clinical evaluation are encountered:
(i) a patient without symptoms of chest pain or discomfort
(ii) a patient with ongoing anginal symptoms
- The former situation is far more prevalent and a normal resting ECG is frequently recorded
- However, even in the absence of repolarization abnormalities, an ECG can demonstrate indirect signs of CAD, such as signs of previous MI (pathological Q waves) or conduction abnormalities [mainly left bundle branch block (LBBB) and
impairment of atrioventricular conduction
- Atrial fibrillation (AF) is a frequent finding in patients with chest pain (usually atypical).
- ST segment depression during supraventricular tachyarrhythmias is not predictive of obstructive CAD
Opinion on ambulatory ECG monitoring in initial assessment of CAD
- Ambulatory ECG monitoring may reveal evidence of silent myocardial ischemia in patients with CCS, but rarely adds relevant diagnostic or prognostic information that cannot be derived from stress testing
- Most importantly, therapeutic strategies targeting silent ischemia detected by ambulatory monitoring have not demonstrated clear survival benefit
Screening recommendations for patients suspected of having CAD
- Total risk estimation using a risk-estimation system such as SCORE is recommended for asymptomatic adults >40 of age without evidence of CVD, diabetes, CKD, ir familial hypercholesterolaemia
- Assessment of family history of premature CVD is recommended as part of cardiovascular risk assessment
- It is recommended that all individuals aged <50 with a family history of premature CVD in a first degree relative or familial hypercholesterolaemia are screened using a validated clinical score
Equations used to estimate GFR
- Chronic kidney disease epidemiology (CKD-EPI) creatinine equation
- Cockcroft-Gault equation
Cockcroft-Gault equation
CrCl (male) = [([140-age] × weight in kg)/(serum creatinine × 72)] x 0.85 if female
Formula to calculate LDL cholesterol
Friedewald formula
Friedewald formula
LDL cholesterol= Total cholesterol - [HDL + (triglycerides/5)]
Resting echo recommendation and why its done
A resting transthoracic echocardiogram is recommended in all patients suspected of having CAD to:
(1) Exclude alternative causes of angina (e.g. pericarditis, valvular heart diseases, HF, and most cardiomyopathies, but it is important to remember that these diseases often coexist with obstructive CAD);
(2) Identify of regional wall motion abnormalities suggestive of CAD;
(3) Measurement of LVEF for risk stratification; and
(4) Evaluation of diastolic function
Typical Echo findings in initial screening for CAD
- LV ejection fraction (LVEF) is often normal in patients with CCS
- A decreased LV function and/or regional wall motion abnormalities may increase the suspicion of ischaemic myocardial damage, and a pattern of LV dysfunction following the theoretical distribution territory of the coronary arteries is typical in patients who have already had an MI
- Decreased diastolic LV function has been reported to be an early sign of ischaemic myocardial dysfunction and could also be indicative of microvascular dysfunction
X-Ray recommendation in patients suspected of having CAD
Chest X-ray is recommended for patients with atypical presentation, signs and symptoms of HF, or suspicion of pulmonary disease
