Tests
1st tests to order
HbA1c
Test
A value of ≥6.5% (≥48 mmol/mol) is a diagnostic test for type 2 diabetes if confirmed with a repeat HbA1c or another type of test (fasting plasma glucose or plasma glucose 2 hours after 75 g oral glucose).[29]
HbA1c is also used to monitor long-term glycemic control.
Result
≥6.5% (≥48 mmol/mol)
lipid profile
Test
Consists of total cholesterol (TC), triglycerides, and LDL-, HDL-, and non-HDL-cholesterol.
TC, HDL-cholesterol (HDL-C), and LDL-cholesterol (LDL-C) levels are required for atherosclerotic CVD risk calculation. The level of LDL-C is a factor in determining intensity of LDL-lowering therapy such as statins, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, or other treatment.[113]
Result
may show elevated TC, LDL-C, and triglycerides, and low HDL-C
Tests to consider
B natriuretic peptide (BNP)/N-terminal prohormone B-natriuretic peptide (NT-proBNP)
Test
Can be considered to screen asymptomatic adults with diabetes for heart failure.[29] If abnormal natriuretic peptide levels are detected, echocardiography is recommended. Identification, risk stratification, and early treatment of risk factors in people with diabetes and asymptomatic stages of heart failure reduce the risk for progression to symptomatic heart failure.[29]
Result
raised levels (BNP ≥35 nanograms/L [≥35 picograms/mL] or NT-proBNP ≥125 nanograms/L [≥125 picograms/mL]) are suggestive of heart failure and warrant further assessment with echocardiography
transthoracic doppler echocardiogram
Test
Transthoracic two-dimensional echocardiography with doppler assessment at rest is a key diagnostic test in evaluation of chest pain or shortness of breath as well as establishing the initial diagnosis and cause of clinical heart failure.[140] Visualization of left and right ventricular function and regional wall motion abnormalities allows for the assessment of CAD risk and may help to guide clinical decision-making. Performance of echocardiography at the bedside is ideal for patients with acute chest pain and can be done using point-of-care or handheld devices in institutions where such capabilities are available.[29]
Result
may be normal; focal wall motion abnormalities may indicate prior myocardial infarction and the extent of any impact on cardiac function
exercise ECG
Test
Exercise ECG testing, with or without echocardiography, may be used as an initial test for patients with cardiac symptoms plus abnormal resting ECG.[29] It is suitable for patients who can exercise and who have a resting ECG that is interpretable for ST-segment shifts.[141][142]
Symptom-limited exercise ECG involves graded exercise until physical fatigue, limiting chest pain, marked ischemia, or a drop in blood pressure occurs. Candidates for exercise ECG are those: a) without disabling comorbidity (e.g., frailty, marked obesity [body mass index >40 kg/m²], peripheral artery disease, chronic obstructive pulmonary disease, or orthopedic limitations) and capable of performing exercise safely; and b) without ST-T abnormalities on resting ECG (e.g., >0.5 mm ST depression, left ventricular hypertrophy, paced rhythm, left bundle branch block, Wolff-Parkinson-White pattern, or digoxin use).[142]
There is a paucity of data on the predictive power of exercise testing in patients with diabetes, but available data suggest that an ischemic finding on exercise ECG is predictive of prognosis.[143] In a study of 1282 patients (15% with diabetes), sensitivity (47% vs. 52%), and specificity (81% vs. 80%) for exercise treadmill testing were similar in people with and without diabetes.[144]
Result
exercise-induced ST depression or arrhythmia
exercise (stress) imaging test
Test
Patients with cardiac symptoms plus abnormal resting ECG who are able to exercise should have an exercise stress test, with or without imaging.[29] If imaging is used, the modality (either echocardiography or nuclear scan [single-photon emission CT/PET) may depend on availability.[141][142] Stress echocardiography can be used to define ischemia severity and for risk stratification purposes. Nuclear imaging enables detection of perfusion abnormalities, measures of left ventricular function, and high-risk findings, such as transient ischemic dilation.[142]
Result
reversible or irreversible wall motion abnormalities
pharmacologic (stress) imaging test
Test
Patients in whom stress testing is indicated, but who have resting ECG abnormalities that preclude exercise stress testing (e.g., left bundle branch block, ventricular pacing) or who are unable to exercise should undergo pharmacologic stress testing with echocardiographic or nuclear (single-photon emission CT or PET) imaging.[29][141][142] Stress echocardiography can be used to define ischemia severity and for risk stratification purposes. Nuclear imaging enables detection of perfusion abnormalities, measures of left ventricular function, and high-risk findings, such as transient ischemic dilation.[142]
Result
reversible or irreversible areas of decreased perfusion
cardiac MRI or stress cardiac MRI
Test
In select patients, such as patients with diabetes with multivessel disease and severe left ventricular dysfunction, cardiac MRI or stress cardiac MRI can be useful.[145] These tests have the capability to accurately assess global and regional left and right ventricular function, detect and localize myocardial ischemia and infarction, and determine myocardial viability, without the need for radiation.[142][145] They can also detect myocardial edema and microvascular obstruction, which can help differentiate acute versus chronic myocardial infarction, as well as other causes of acute chest pain, including myocarditis.[142]
However, do not recommend performing stress cardiac MRI in patients with acute chest pain and high probability of CAD/ACS.[146] Stress cardiac MRI can increase risk and delay treatment in patients with acute chest pain and markers of high risk, such as ST segment elevation and/or positive cardiac biomarkers.[146]
Result
reversible or irreversible areas of decreased perfusion; also defines cardiac anatomy, chamber size/function, and valvular pathology
ankle-brachial index (ABI)
Test
Joint American Heart Association and American College of Cardiology guidelines recommend that all patients with history or physical examination findings suggestive of peripheral arterial disease (PAD) should have a resting ABI measured, with or without ankle pulse volume recordings and/or Doppler waveforms.[28] Screening with resting ABI is also considered reasonable in patients with any of the following characteristics: age ≥65 years or older; age 50 to 64 with risk factors for atherosclerosis (e.g., diabetes, smoking history, dyslipidemia, hypertension), chronic kidney disease, or family history of PAD; age <50 years with diabetes and one additional risk factor for atherosclerosis; patients with known atherosclerotic disease in another vascular bed (e.g., coronary, carotid, subclavian, renal, mesenteric artery stenosis, or abdominal aortic aneurysm).[28] The American Diabetes Association recommends screening for PAD using ABI in asymptomatic people with any of the following characteristics: age ≥50 years; diabetes with duration ≥10 years; comorbid microvascular disease; clinical evidence of foot complications; or any end-organ damage from diabetes.[29]
ABI may not be accurate in patients with noncompressible arteries, such as those with long-standing diabetes mellitus or chronic kidney disease (CKD), particularly those on dialysis. Diagnosis of PAD should not be excluded based on normal or raised ankle brachial pressure index alone in people with diabetes or CKD.[28] See Peripheral arterial disease.
Result
ABI 1.0 to 1.4 normal; 0.91 to 0.99 borderline; ≤0.9 abnormal
CT coronary angiography
Test
CT angiography may be useful for patients with equivocal myocardial perfusion scanning, for ruling out left main or triple-vessel coronary artery disease (CAD), patients with nonischemic cardiomyopathy, and young patients undergoing valvular surgery.[148]
Screening asymptomatic obstructive CAD among high-risk patients with diabetes using CT angiography is not recommended.[151] Do not use CT angiography in high-risk emergency patients presenting with acute chest pain.[150][152]
Result
defines coronary anatomy, location and degree of stenosis
CT coronary calcium scan
Test
Studies using ≥16-slice CT scanners have shown that coronary artery calcium (CAC) score >400 is associated with high likelihood of inducible myocardial ischemia and should prompt further testing.[147] In patients with pretest likelihood of CAD <50%, a CAC score of 0 provides very strong evidence against the presence of CAD, with a high degree of certainty.[148]
Do not order a CAC scan in patients with known atherosclerotic disease, including those with stents and bypass grafts, as it offers limited incremental prognostic value for these individuals.[149][150]
Result
defines coronary calcium burden
invasive coronary angiography
Test
Coronary angiography after injection of radiopaque dye is usually reserved for patients with acute coronary syndrome, frequent angina, high-risk and/or high pretest probability of CAD that requires surgical or percutaneous intervention, and/or high-risk findings on stress testing.[142]
Result
defines coronary anatomy, location and degree of stenosis; directs medical or mechanical therapy
noncontrast head CT
Test
First test to obtain if symptoms suggest possible acute stroke.
Result
acute cerebrovascular accident
brain MRI
Test
Used to further evaluate for possible acute stroke, especially white matter lesions, brainstem, and posterior fossa lesions.
Result
acute, subacute, or prior cerebrovascular accident
duplex ultrasonography of carotid arteries
Test
Patients with symptomatic stenosis ≥50% may be candidates for intervention as well as asymptomatic patients with a stenosis ≥70%.[164]
Result
degree of stenosis in carotid arteries
C-reactive protein
chest x-ray
Test
A chest x-ray is not a routine test but may be useful to assess heart size and pulmonary congestion and evaluate for alternative causes of dyspnea.
The sensitivity of chest x-ray for making a diagnosis is poor. For example, 1 in 5 individuals with acute heart failure has no signs of congestion on a chest x-ray.[140]
Result
can evaluate the lung parenchyma, pleural space, and cardiomegaly
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