Role of adjuvant carotid ultrasound in women undergoing stress echocardiography for the assessment of suspected coronary artery disease

Abstract

Objective: Due to the low prevalence of obstructive coronary artery disease (CAD) in women, stress testing has a relatively low predictive value for this. Additionally, conventional cardiovascular risk scores underestimate risk in women. This study sought to evaluate the role of atherosclerosis assessment using carotid ultrasound (CU) in women attending for stress echocardiography (SE).

Methods: This was a prospective study in which consecutive women with recent-onset suspected angina, who were referred for clinically indicated SE, underwent CU.

Results: 415 women (mean age 61±10 years, 29% diabetes mellitus, mean body mass index 28) attending for SE underwent CU. 47 women (11%) had inducible wall motion abnormalities, and carotid disease (CD) was present in 46% (carotid plaque in 41%, carotid intima-media thickness >75th percentile in 15%). Women with CD were older (65 vs 58 years, p<0.001), and more likely to have diabetes (41% vs 21%, p=0.001), hypertension (67% vs 36%, p<0.01) and a higher pretest probability of CAD (59% vs 41%, p<0.001). 40% of women classified as low Framingham risk were found to have evidence of CD.The positive predictive value of SE for flow-limiting CAD was 51%, but with the presence of carotid plaque, this was 71% (p<0.01). Carotid plaque (p=0.004) and ischaemia (p=0.01) were the only independent predictors of >70% angiographic stenosis. In women with ischaemia on SE and no carotid plaque, the negative predictive value for flow-limiting disease was 88%.During a follow-up of 1058±234 days, there were 15 events (defined as all-cause mortality, non-fatal myocardial infarction, heart failure admissions and late coronary revascularisation). Age (HR 1.07 (1.00-1.15), p=0.04), carotid plaque burden (HR 1.65 (1.36-2.00), p<0.001) and ischaemic burden (HR 1.41 (1.18-1.68), p<0.001) were associated with outcome. There was a stepwise increase in events/year from 0.3% when there were no ischaemia and atherosclerosis, 1.1% when there was atherosclerosis and no ischaemia, 2.2% when there was ischaemia and no atherosclerosis and 10% when there were both ischaemia and atherosclerosis (p<0.001).

Conclusion: CU significantly improves the accuracy of SE alone for identifying flow-limiting disease on coronary angiography, and improves risk stratification in women attending for SE, as well identifying a subset of women who may benefit from primary preventative measures.

Keywords: atherosclerosis; carotid artery disease; stress.

Figure 1

An example of a 59-year-old woman with atypical chest pain and exertional dyspnoea. On exercise echocardiography she exercised for 5.0 metabolic equivalents (METs) and developed left ventricular dilatation at peak stress, with inducible wall motion abnormalities seen in 9/16 wall segments (A–D). Carotid ultrasound (E) and coronary angiography (F) were entirely normal.

Figure 2

Kaplan-Meier survival curve demonstrating freedom from events based on stress echocardiography result (ischaemia vs no ischaemia). SE, stress echocardiography.

Figure 3

Kaplan-Meier survival curve demonstrating freedom from events based on carotid ultrasound result (carotid plaque vs no plaque). CP, carotid plaque.

Figure 4

A 55-year-old woman presented with left-sided chest pains. Exercise echocardiography was normal (A–D) and carotid ultrasound (CU) demonstrated a large burden of echolucent plaque in the carotid bulb (E). She presented 3 weeks later with a non-ST elevation myocardial infarction and angiography (F) demonstrated a subtotal occlusion of the proximal left anterior descending coronary artery (LAD) with heavy thrombus burden (white arrow) which was stented.

Figure 5

A suggested multimodality algorithm in women with suspected coronary artery disease (CAD). Women with ischaemia and carotid plaque (CP) should undergo invasive coronary angiography since the probability of flow-limiting disease (FLD) is 70%. In contrast, women with ischaemia and no CP may undergo CT coronary angiography since the prevalence of FLD is only around 10%. Where FLD is not demonstrated, assessment of coronary flow reserve (CFR) should be performed invasively or non-invasively using myocardial contrast echocardiography (MCE), Doppler echocardiography, cardiac magnetic resonance (CMR) or positron emission tomography (PET). Women with no ischaemia and CP may benefit from aggressive risk factor modification and lifestyle measures. Where there is no ischaemia or CP, women can be safely discharged since the prognosis is excellent. CU, carotid ultrasound; LDL, low-density lipoprotein; PTP, pretest probability; SE, stress echocardiography.