{"product_id":"seeing-the-problem-before-it-happens-how-carotid-ultrasound-helps-predict-heart-attacks-and-strokes","title":"Seeing the Problem Before It Happens: How Carotid Ultrasound Helps Predict Heart Attacks and Strokes","description":"\u003cp\u003eCarotid ultrasound (an imaging test that uses sound waves to picture the neck arteries) can quickly and reliably measure how much atherosclerosis — fatty plaque buildup — a person has. A large body of research shows that measuring the total area of carotid plaque predicts future heart attacks and strokes. This is better than traditional risk factors or than measuring only the artery's inner lining thickness. Carotid plaque volume has predictive power comparable to coronary calcium scoring, but it avoids radiation exposure. European guidelines now suggest considering a carotid scan to refine risk estimates, especially for people who fall into the intermediate-risk group.\u003c\/p\u003e\n\n\u003ch1\u003eBonn Zurich Sonographic assessment of carotidatherosclerosis\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eWhy This Matters: The Burden of Cardiovascular Disease\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#problem\"\u003eThe Problem with Traditional Risk Calculators\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#technical\"\u003eHow Carotid Ultrasound Works\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#measure\"\u003eMeasuring Plaque: IMT, TPA, and TPV Explained\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#outcomes\"\u003eWhat the Research Shows: Large Outcome Studies\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#meta\"\u003eMeta-Analyses: Carotid Plaque Beats IMT\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#direct\"\u003eDirect Comparison: Carotid Plaque vs. Coronary Calcium\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#treatment\"\u003eCould Treatment Shrink Carotid Atherosclerosis?\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#choose\"\u003eWhat Should Be Measured — and What Is Practical?\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#implications\"\u003eClinical Implications for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eLimitations and Open Questions\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations and Actionable Advice\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCarotid ultrasound measures plaque buildup in neck arteries and predicts heart attacks and strokes better than traditional risk factors or intima-media thickness alone.\u003c\/li\u003e\n\u003cli\u003eIn the BioImage study of 5,808 healthy subjects, carotid total plaque volume was noninferior to coronary calcium for predicting cardiovascular events, without radiation.\u003c\/li\u003e\n\u003cli\u003eEuropean guidelines suggest considering a carotid scan to refine risk estimates, especially for people classified as intermediate risk by standard calculators.\u003c\/li\u003e\n\u003cli\u003eA meta-analysis of 41 trials with 18,307 participants found active treatment reduced cardiovascular events and death, but IMT reduction did not correlate with fewer events.\u003c\/li\u003e\n\u003cli\u003eTotal plaque area is considered the most practical measurement for clinical practice because it is reproducible, vendor-independent, and requires no extra software.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eWhy This Matters: The Burden of Cardiovascular Disease\u003c\/h2\u003e\n\n\u003cp\u003eWhenever illness or injury occurs, a natural question arises: could it have been prevented? That question drives a huge amount of ongoing research into identifying which factors predict future risk — so that risk can be managed and eventually reduced.\u003c\/p\u003e\n\n\u003cp\u003eThe INTERHEART study showed that major, independent cardiovascular risk factors together contribute to 90% of cardiovascular events (heart attacks and strokes). According to the Swiss Federal Statistical Office, cardiovascular and cancer diseases remained the leading causes of death in Switzerland in 2015. National Health Accounts were highest for cardiovascular disease, at 15.6%. Cardiovascular disease together with cancer accounted for 22% of healthcare spending in Switzerland.\u003c\/p\u003e\n\n\u003cp\u003ePreventing diseases linked to atherosclerosis is therefore a primary healthcare issue. Traditionally, primary care doctors assess atherosclerosis risk by looking for established risk factors. The modification of just seven risk factors has great potential to prevent premature illness and death across the population. Those seven factors are:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eSmoking\u003c\/li\u003e\n  \u003cli\u003eHigh blood pressure\u003c\/li\u003e\n  \u003cli\u003eHigh cholesterol\u003c\/li\u003e\n  \u003cli\u003eObesity\u003c\/li\u003e\n  \u003cli\u003eSedentary (inactive) lifestyle\u003c\/li\u003e\n  \u003cli\u003eMalnutrition (poor diet)\u003c\/li\u003e\n  \u003cli\u003eDiabetes mellitus (high blood sugar)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eDespite this, many patients arrive at hospital with their first ischaemic event. An ischaemic event is a heart attack or stroke caused by blocked blood flow. Yet those same patients had been classified as low-risk by standard risk calculators such as PROCAM and SCORE.\u003c\/p\u003e\n\n\u003ch2 id=\"problem\"\u003eThe Problem with Traditional Risk Calculators\u003c\/h2\u003e\n\n\u003cp\u003eDirect visualisation of atherosclerosis may therefore be warranted. Seeing plaque in the arteries could help reclassify people according to their true individual risk, rather than relying on risk formulas alone.\u003c\/p\u003e\n\n\u003cp\u003eThe authors previously studied two populations — one from Olten, Switzerland, and one from Koblenz, Germany. They showed that the sensitivity of global risk calculators such as PROCAM and SCORE is low for detecting advanced carotid atherosclerosis. Sensitivity is the ability to correctly detect disease when it is present. Advanced carotid atherosclerosis was measured as the total carotid plaque area. They also found that agreement between PROCAM and SCORE regarding risk category appears to be limited. This is the rationale for adding ultrasound to atherosclerosis management — the topic of this review.\u003c\/p\u003e\n\n\u003ch2 id=\"technical\"\u003eHow Carotid Ultrasound Works\u003c\/h2\u003e\n\n\u003cp\u003eCarotid ultrasound is performed with a linear array probe — a flat-headed scanning device — at a high frequency of at least 7 MHz. This frequency is needed to obtain sufficient resolution to image very small structures. Image resolution depends on the depth of the tissue and the frequency used, and is usually around 0.3 mm.\u003c\/p\u003e\n\n\u003cp\u003eThe anatomical region of interest is the tunica intima, the innermost layer of the artery wall. It is assessed with 2D imaging without Doppler (the colour-flow overlay used in some scans). Intima-media thickness (IMT) is the distance between the endothelium (the inner lining of the artery) and the tunica adventitia (the outer supporting layer).\u003c\/p\u003e\n\n\u003cp\u003eAccording to the Mannheim consensus, IMT is preferably measured in the far wall of the last 10 mm of the common carotid artery. The Mannheim consensus is an international agreement on how to standardise these measurements. One major problem with carotid IMT measurements is that researchers use many different methods, as described extensively elsewhere.\u003c\/p\u003e\n\n\u003cp\u003eThe variability of carotid IMT measurements is lowest in the far wall of the common carotid artery when carotid plaque is excluded. However, this improvement in reproducibility comes with a real cost: it reduces the ability to predict cardiovascular events.\u003c\/p\u003e\n\n\u003cp\u003eCarotid ultrasound has several practical advantages for clinical use. It is rapid and reliable, it is vendor-independent (meaning no additional software costs for tracing plaque on the image), and results can be obtained without extra software.\u003c\/p\u003e\n\n\u003ch2 id=\"measure\"\u003eMeasuring Plaque: IMT, TPA, and TPV Explained\u003c\/h2\u003e\n\n\u003cp\u003eThe definition of atherosclerotic plaque versus non-atherosclerotic intimal thickening has not been applied uniformly in the literature. For clinical purposes, the most commonly used definition is an IMT increase of more than 1.5 mm, or a focal thickening of more than 50% compared with adjacent structures.\u003c\/p\u003e\n\n\u003cp\u003eResearchers have proposed many different ways to quantify carotid plaque. These are summarised in the article's reference table and include:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eIncrease of IMT greater than 1.0 mm (Spence, 1991)\u003c\/li\u003e\n  \u003cli\u003eDoubling of IMT (Spence, 1991; Mannheim Consensus)\u003c\/li\u003e\n  \u003cli\u003eThickening of IMT greater than 1.2 mm (Handa)\u003c\/li\u003e\n  \u003cli\u003eSubjective visual assessment (Polak; Peters, for plaque burden from none to severe)\u003c\/li\u003e\n  \u003cli\u003eEncroaching into the lumen by 0.5 mm (Mannheim Consensus)\u003c\/li\u003e\n  \u003cli\u003eIncrease of IMT of 1.5 mm or more (Mannheim Consensus; Spence)\u003c\/li\u003e\n  \u003cli\u003eTexture changes (Singh)\u003c\/li\u003e\n  \u003cli\u003ePlaque present yes or no (Nambi)\u003c\/li\u003e\n  \u003cli\u003eNumber of plaques (Plichart)\u003c\/li\u003e\n  \u003cli\u003ePlaque thickness in millimetres (Rundek)\u003c\/li\u003e\n  \u003cli\u003ePlaque area in square millimetres (Spence)\u003c\/li\u003e\n  \u003cli\u003ePlaque volume in cubic millimetres (Baber)\u003c\/li\u003e\n  \u003cli\u003eEcho lucency (brightness on grayscale imaging) (Stein)\u003c\/li\u003e\n  \u003cli\u003ePlaque vascularity using a contrast agent (Coli)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eTwo newer measures are central to this review. The first is \u003cstrong\u003etotal plaque area (TPA)\u003c\/strong\u003e — the sum of the longitudinal area of all plaques in the carotid wall. It is measured from the clavicles up to the jaw, using multiple angles. This captures the full longitudinal circumference of all plaques in the carotid tree, including the proximal brachial artery if possible.\u003c\/p\u003e\n\n\u003cp\u003eThe second is \u003cstrong\u003etotal plaque volume (TPV)\u003c\/strong\u003e. This recently became available using the Philips iU 22 ultrasound system, equipped with a single-sweep volumetric transducer. That probe covers 3.8 cm of the carotid artery and visualises the distal part of the common carotid artery, the bulb, and the proximal parts of the internal carotid artery. Off-line software calculates plaque areas from all the transversal images to produce the total plaque volume.\u003c\/p\u003e\n\n\u003cp\u003eBecause the field of view is only 3.8 cm, some plaques located proximal or distal to the transducer are missed. Those plaques are instead captured by the total plaque area derived from longitudinal carotid images. The advantage of the longitudinal plaque imaging (TPA technique) is its high reproducibility, its vendor independence, and the fact that no additional software is needed. The correlation between TPA and TPV is strong: the correlation coefficient is r² = 0.921 (p \u0026lt;0.0001).\u003c\/p\u003e\n\n\u003cp\u003eThe most complete picture of total plaque burden therefore comes from TPA, followed by TPV and then IMT. However, TPV can capture plaques located laterally in the vessel wall that the TPA method cannot see. For this reason, TPA should also incorporate lateral plaque seen on transversal images.\u003c\/p\u003e\n\n\u003ch2 id=\"outcomes\"\u003eWhat the Research Shows: Large Outcome Studies\u003c\/h2\u003e\n\n\u003cp\u003eOutcome studies linking the amount of carotid atherosclerosis to heart and brain ischaemic events are numerous. The largest cohorts — each with at least 4,000 participants — are summarised below.\u003c\/p\u003e\n\n\u003cp\u003eOne of the first studies on the prognostic impact of carotid ultrasound imaging appeared in 1991. In 1,288 Finnish men, coronary event risk rose as follows:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntimal thickening:\u003c\/strong\u003e 2.2-fold increase in risk (p = not significant)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSmall carotid plaques:\u003c\/strong\u003e 4.2-fold increase (p \u0026lt;0.01)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStenotic plaque (narrowing of the artery):\u003c\/strong\u003e 6.7-fold increase (p \u0026lt;0.01)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn 1995, Japanese researchers found that carotid stenosis and plaque ulcerations predicted ischaemic stroke. In 1996, Belcaro and colleagues found that increases in plaque burden in the carotid and femoral arteries predicted cardiovascular events and death in 2,322 asymptomatic people after six years of follow-up. The same finding held in 13,221 low-risk subjects (the CAFES-CAVE study) after 10 years.\u003c\/p\u003e\n\n\u003cp\u003eSpence showed in 2002 that TPA predicted cardiovascular events, with risk increasing in the higher quartiles of total plaque area. That analysis included 1,686 patients, most of whom had already had a stroke or transient ischaemic attack (TIA — a \"mini-stroke\" that resolves). Of these, 684 were originally primary care patients. For that primary care group, adding posterior test probabilities based on the Bayes theorem improved discrimination for predicting future heart attacks after 3.3 years of follow-up. The area under the curve was 0.68 for the NCEP III risk score. The area under the curve is a measure of how well a test separates people who will have events from those who won't. The area under the curve rose to 0.75 for the TPA-based posterior test probability (p = 0.038).\u003c\/p\u003e\n\n\u003cp\u003eOther landmark findings include:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2003 (Hollander, Rotterdam study):\u003c\/strong\u003e In 6,913 prospectively followed healthy subjects, carotid IMT (including regions with plaque) was a stronger predictor of subsequent stroke than carotid plaque alone.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2004 (van der Meer, Rotterdam study):\u003c\/strong\u003e In 6,389 subjects assessed for structural changes, all measures — carotid and femoral plaque, carotid IMT with plaque included, and aortic plaque — had equal predictive power for ensuing heart attacks.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2007 (Stein, Tromsø study):\u003c\/strong\u003e In 6,226 originally healthy people, TPA was a stronger and statistically significant marker of incident heart attacks than IMT, especially in women, after correction for several conventional risk factors. This observation remained significant after extended follow-up of 15 years.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eXie et al. (China):\u003c\/strong\u003e In 1,734 subjects screened for future heart attacks and strokes, all measures of carotid structural change (IMT at six sites, TPA, and number of plaques) were effective for risk prediction after adjustment for conventional risk factors.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2010 (Lorenz, Atherosclerosis Progression Study):\u003c\/strong\u003e In 4,904 low-risk patients followed for 10 years, carotid IMT measured at the common carotid artery, the bulb, and the internal carotid artery was \u003cem\u003eless\u003c\/em\u003e predictive than the Framingham and SCORE risk models — but only 5% of these subjects actually had carotid plaques.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2010 (Chambless, ARIC study):\u003c\/strong\u003e In 13,145 subjects followed for 15 years, the AUC increased significantly when carotid IMT or carotid plaque was added to traditional risk factors.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2011 (Mathiesen, Tromsø study):\u003c\/strong\u003e In 6,584 subjects, TPA — but not common carotid IMT — predicted incident ischaemic stroke after multivariate adjustment.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2011 (Polak, Framingham Offspring Study):\u003c\/strong\u003e In 2,965 members followed for 7 years, both internal carotid IMT and internal carotid plaque formation (defined as IMT of 1.5 mm or more) significantly improved the AUC compared with the Framingham risk equation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe article notes that Naqvi has published an excellent, comprehensive overview of outcome studies performed with carotid ultrasound.\u003c\/p\u003e\n\n\u003cp\u003eBelow are the specific hazard ratios (HR — how many times more likely an event is in one group versus another) from the major cohort studies:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCAFES-CAVE (10,000 people, death):\u003c\/strong\u003e No plaque — 0.1% event rate; carotid plaque — 3.0% event rate\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRotterdam (6,389 people, heart attack):\u003c\/strong\u003e Plaque yes\/no — HR 1.6, 95% confidence interval (CI) 1.2–2.2\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRosvall (5,163 people, heart attack):\u003c\/strong\u003e Plaque yes\/no — HR 1.8, 95% CI 1.5–2.9; IMT lowest third vs highest third — HR 1.5, 95% CI 0.8–2.6\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRosvall (5,163 people, stroke):\u003c\/strong\u003e Plaque yes\/no — HR 1.3, 95% CI 0.8–2.1; IMT tertiles — HR 2.5, 95% CI 1.2–5.4\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eARIC men (5,552 people, heart attack):\u003c\/strong\u003e IMT ≥1.0 mm — HR 1.9, 95% CI 1.3–2.7\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eARIC women (7,685 people, heart attack):\u003c\/strong\u003e IMT ≥1.0 mm — HR 5.1, 95% CI 3.1–8.4\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eARIC women (7,685 people, stroke):\u003c\/strong\u003e IMT \u0026lt;0.6 vs \u0026gt;1.0 mm — HR 8.5, 95% CI 3.5–20.7\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eARIC men (6,349 people, stroke):\u003c\/strong\u003e IMT \u0026lt;0.6 vs \u0026gt;1.0 mm — HR 3.6, 95% CI 1.5–9.2\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTromsø (6,257 people, heart attack):\u003c\/strong\u003e TPA tertiles — HR 2.5, 95% CI 2.1–3.0\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTromsø men (6,226, heart attack):\u003c\/strong\u003e TPA tertiles — HR 1.6, 95% CI 1.04–2.4; IMT quartiles — HR 1.7, 95% CI 0.98–3.1\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTromsø women (6,226, heart attack):\u003c\/strong\u003e TPA tertiles — HR 4.0, 95% CI 2.2–7.2; IMT quartiles — HR 2.9, 95% CI 1.1–7.7\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTromsø men (6,844, stroke):\u003c\/strong\u003e TPA tertiles — HR 1.7, 95% CI 1.2–2.5; IMT quartiles — HR 1.4, 95% CI 0.8–2.4\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTromsø women (6,844, stroke):\u003c\/strong\u003e TPA tertiles — HR 1.6, 95% CI 1.04–2.5; IMT quartiles — HR 1.3, 95% CI 0.7–2.3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMESA (6,698 people, cardiovascular disease):\u003c\/strong\u003e IMT quartile — HR 1.7, 95% CI 1.2–2.5\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMESA (4,955 people, cardiovascular disease):\u003c\/strong\u003e Carotid score — HR 1.2, 95% CI 1.2–1.4\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"meta\"\u003eMeta-Analyses: Carotid Plaque Beats IMT\u003c\/h2\u003e\n\n\u003cp\u003eSeveral more recent reviews and meta-analyses (studies that pool data from many smaller studies) have tried to put different imaging methods into perspective.\u003c\/p\u003e\n\n\u003cp\u003eSimons analysed the prognostic impact of carotid IMT compared with carotid plaques using c-statistics (a statistical measure of prediction accuracy). Carotid IMT was not superior to the Framingham risk score for predicting ischaemic heart disease.\u003c\/p\u003e\n\n\u003cp\u003eIn 2012, Den Ruijter and colleagues published a meta-analysis of 14 population-based cohorts with data from 45,828 subjects, comparing common carotid IMT with the Framingham risk score. They found a modest improvement in reclassification and hazard ratio, but not for AUC:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eFramingham AUC: 0.76 (95% CI 0.75–0.76)\u003c\/li\u003e\n  \u003cli\u003eCarotid IMT AUC: 0.76 (95% CI 0.75–0.77)\u003c\/li\u003e\n  \u003cli\u003eComparison of AUCs: no statistically significant improvement\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eInaba and colleagues published a meta-analysis of 11 population-based studies that included 54,336 patients. Compared with carotid IMT, carotid plaque was a significantly better predictor of future heart attacks:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eCarotid plaque AUC: 0.64 (95% CI 0.61–0.67)\u003c\/li\u003e\n  \u003cli\u003eCarotid IMT AUC: 0.61 (95% CI 0.59–0.64)\u003c\/li\u003e\n  \u003cli\u003eRelative diagnostic odds ratio: 1.4 (95% CI 1.1–1.8); p = 0.04\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"direct\"\u003eDirect Comparison: Carotid Plaque vs. Coronary Calcium\u003c\/h2\u003e\n\n\u003cp\u003eEarly outcome studies compared one imaging method against traditional risk factors. Two large-scale studies — BioImage and MESA — went further and directly compared coronary calcification (calcium deposits in the heart's arteries) with carotid ultrasound imaging.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eThe BioImage study\u003c\/strong\u003e involved 5,808 healthy subjects and was published in 2015 by Baber and colleagues. It directly compared the total volume of carotid plaques acquired with the Philips iU 22 ultrasound system. This was compared against the presence and amount (score) of coronary calcium. Coronary calcium measures the total calcified plaque burden across the whole coronary tree. In a low- to intermediate-risk population, carotid total plaque volume was \u003cem\u003enoninferior\u003c\/em\u003e (no worse than) coronary calcium for predicting cardiovascular events — and it avoided radiation.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eThe MESA study\u003c\/strong\u003e included 6,779 healthy subjects and was published by Gepner and colleagues in 2015. It compared the presence of coronary calcium with the presence of carotid plaques and carotid IMT above the 75th percentile. Only coronary calcium and carotid plaque presence were predictive; carotid IMT was not. For predicting stroke or transient ischaemic attack, only the presence of carotid plaques was predictive after 9.5 years of observation.\u003c\/p\u003e\n\n\u003cp\u003eFor context, here are the key coronary artery calcification (CAC) findings:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eRaggi (10,377 people, death): AUC 0.72–0.78, p = 0.001\u003c\/li\u003e\n  \u003cli\u003eDetrano (6,772 people, major adverse cardiovascular events): AUC 0.79–0.83, p = 0.009\u003c\/li\u003e\n  \u003cli\u003eArad (4,903 people, major events): AUC 0.68–0.79, p = 0.001\u003c\/li\u003e\n  \u003cli\u003eErbel (4,129 people, major events): AUC 0.65–0.76, p = 0.001\u003c\/li\u003e\n  \u003cli\u003eMESA (6,814 people, major events): AUC 0.75–0.80, p = 0.001\u003c\/li\u003e\n  \u003cli\u003eMESA (6,698 people, cardiovascular disease): highest vs lowest quartile — HR 4.4, 95% CI 2.8–6.8\u003c\/li\u003e\n  \u003cli\u003eMESA (4,955 people, cardiovascular disease): HR 1.78, 95% CI 1.16–1.98\u003c\/li\u003e\n  \u003cli\u003eMESA (6,814 people, cardiovascular disease): CAC score of 0 — event rate 1.3–5.6%; CAC score above 300 — event rate 13.1–25.6%\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"treatment\"\u003eCould Treatment Shrink Carotid Atherosclerosis?\u003c\/h2\u003e\n\n\u003cp\u003eA meta-analysis of 41 randomised trials, including 18,307 participants and published in 2010, showed that active treatment significantly reduced cardiovascular events and all-cause death. However, there was no significant relationship between the reduction in IMT and cardiovascular events. This was later confirmed in a second meta-analysis by Goldberger and colleagues.\u003c\/p\u003e\n\n\u003cp\u003eThe picture was not confirmed in the IMPROVE-IT study, which included 3,703 high-risk patients (average Framingham risk score 22%). There, carotid IMT and its progression — but not carotid plaque — led to significant improvements in risk reclassification.\u003c\/p\u003e\n\n\u003cp\u003eThis means that measuring plaque burden may be more useful than measuring IMT alone when tracking whether treatment is working.\u003c\/p\u003e\n\n\u003ch2 id=\"choose\"\u003eWhat Should Be Measured — and What Is Practical?\u003c\/h2\u003e\n\n\u003cp\u003eRegardless of traditional risk factors, structural arterial changes revealed by atherosclerosis imaging are associated with adverse cardiovascular outcomes. Screening with atherosclerosis imaging has not received a class I recommended indication in primary care (the strongest level of medical recommendation). Yet most cardiovascular events occur in people who are \u003cem\u003enot\u003c\/em\u003e classified as high risk by traditional risk factors. By inference, additional testing might help with further risk stratification.\u003c\/p\u003e\n\n\u003cp\u003eAdding carotid plaque quantification to cardiovascular risk prediction has significantly improved discrimination and reclassification of subjects in primary care. Carotid plaque is caused by atherosclerosis involving foam cells, smooth muscle cells, calcifications, macrophages, lipid cores, and a fibrous cap. However, the definition of plaque on ultrasound is not uniform.\u003c\/p\u003e\n\n\u003cp\u003eSeveral factors influence which test a clinician chooses:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eExpertise and availability — unavoidable requirements\u003c\/li\u003e\n  \u003cli\u003eCost\u003c\/li\u003e\n  \u003cli\u003eRadiation burden\u003c\/li\u003e\n  \u003cli\u003eValidity\u003c\/li\u003e\n  \u003cli\u003eReproducibility\u003c\/li\u003e\n  \u003cli\u003eFeasibility\u003c\/li\u003e\n  \u003cli\u003eTest rapidity\u003c\/li\u003e\n  \u003cli\u003eThe ability to track atherosclerosis over time to observe treatment effects\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn the authors' opinion, carotid total plaque area (TPA) is probably the most suited for clinical practice. They recommend following this with a search for femoral bifurcation plaque and aortic plaque. They also recommend use of the ankle-arm index, which compares blood pressure at the ankle and arm. Another option is measurement of plaque height with ultrasound in various vascular beds.\u003c\/p\u003e\n\n\u003cp\u003eMore sophisticated tests are often time-consuming and costly, or involve radiation exposure — though it has recently been shown that radiation exposure can be reduced. The acquisition of IMT is technically demanding. It requires an ECG signal to time images during diastole (the heart's resting phase) and a room temperature of 22–25°C. Plaque should not be excluded from measurements, in order to improve predictive accuracy for cardiovascular events.\u003c\/p\u003e\n\n\u003cp\u003eLaclaustra reported a comparative study that used the presence (score above 0) and extent (score above 300) of coronary calcium as the gold standard. That study compared traditional risk factors, 3D carotid plaque volumes, and 3D femoral plaque volumes for correctly detecting coronary calcium within the same subject. Both carotid and femoral plaque were better markers for the presence and extent of coronary calcifications than traditional risk factors. There was a tendency toward better performance of femoral over carotid plaque, especially in smokers.\u003c\/p\u003e\n\n\u003ch2 id=\"implications\"\u003eClinical Implications for Patients\u003c\/h2\u003e\n\n\u003cp\u003eCardiovascular risk increases with the carotid plaque burden quantified as total plaque area. What does this mean for patients?\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eIf you have been told you are \"low risk\" or \"intermediate risk\" based on a calculator, a carotid ultrasound may reveal plaque you didn't know about. A carotid ultrasound may change your true risk category.\u003c\/li\u003e\n  \u003cli\u003eCarotid plaque measurement appears more informative than intima-media thickness for predicting heart attacks and strokes.\u003c\/li\u003e\n  \u003cli\u003eCarotid plaque volume has predictive power comparable to coronary calcium scoring, but without radiation exposure.\u003c\/li\u003e\n  \u003cli\u003eThe European Joint ESC guidelines now say a carotid artery scan should be considered for adjusting risk levels, especially in intermediate-risk subjects.\u003c\/li\u003e\n  \u003cli\u003eTracking plaque over time — its presence, progression, stability, or regression — may be a valuable clinical tool for optimising the intensity of preventive therapies.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWays to incorporate imaging results into clinical decision-making include using \"arterial age\" instead of chronological age in risk equations. Another way is calculating post-test risk using the sensitivity and specificity of a given carotid plaque burden result. For example, the Bayes theorem formula for the post-test probability of disease when a test is positive is: (prevalence × sensitivity) ÷ [prevalence × sensitivity + (1 – prevalence) + (1 – specificity)]. The formula for a negative test is: [prevalence × (1 – sensitivity)] ÷ [prevalence × (1 – sensitivity) + specificity × (1 – prevalence)].\u003c\/p\u003e\n\n\u003cp\u003eIn subjects with low or intermediate cardiovascular risk, the search for atherosclerosis may be appropriate. Ultrasound of the carotid or femoral arteries could be the primary method applied, depending on local expertise.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eLimitations and Open Questions\u003c\/h2\u003e\n\n\u003cp\u003eThis review is not a single new study; it is a synthesis of existing research, and several limitations are apparent across that body of work.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eThe definition of carotid plaque on ultrasound is not uniform, which makes comparisons between studies difficult.\u003c\/li\u003e\n  \u003cli\u003eCarotid IMT measurements are affected by a diversity of methods. Variability is only lowest when plaque is excluded from the common carotid far wall. That is the very approach that reduces event prediction.\u003c\/li\u003e\n  \u003cli\u003eCarotid total plaque volume covers only a 3.8 cm field of view, so some plaques proximal or distal to the transducer are missed.\u003c\/li\u003e\n  \u003cli\u003eActive treatment reduced cardiovascular events and death in a meta-analysis of 41 trials. But IMT reduction did not correlate with event reduction in that analysis. This leaves it unclear exactly how to monitor treatment success.\u003c\/li\u003e\n  \u003cli\u003eScreening with atherosclerosis imaging has not been given a class I recommendation in primary care.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThese gaps suggest that standardised plaque definitions and further head-to-head outcome studies remain needed.\u003c\/p\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations and Actionable Advice\u003c\/h2\u003e\n\n\u003cp\u003eBased on this review, the following practical steps can be considered by patients and their clinicians:\u003c\/p\u003e\n\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eKnow your risk category.\u003c\/strong\u003e If a standard calculator such as PROCAM or SCORE places you at low or intermediate risk, remember this. Many people who have a first heart attack or stroke were classified this way.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAsk about carotid ultrasound.\u003c\/strong\u003e The latest European Joint ESC guidelines state that carotid artery scanning should be considered for adjusting the level of risk, especially in intermediate-risk subjects.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFocus on total plaque area if a scan is done.\u003c\/strong\u003e The authors consider TPA the most practical measurement for clinical practice, because it is highly reproducible, vendor-independent, and does not require extra software.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConsider femoral and aortic plaque screening too.\u003c\/strong\u003e Where local expertise allows, ultrasound of the carotid or femoral arteries may be appropriate; femoral plaque performed at least as well as carotid plaque in one comparison, especially in smokers.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTrack change over time.\u003c\/strong\u003e Assessing plaque presence, progression, stability, and regression may help optimise the intensity of preventive therapy, because carotid IMT reduction alone did not track with better outcomes in pooled trial data.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eContinue to control the seven modifiable risk factors:\u003c\/strong\u003e smoking, blood pressure, cholesterol, obesity, sedentary lifestyle, poor nutrition, and diabetes.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003eIn short, carotid ultrasound is a rapid, radiation-free, and increasingly well-validated tool. When used as an addition to — not a replacement for — traditional risk assessment, it may give both patients and doctors a clearer picture of true cardiovascular risk.\u003c\/p\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat is carotid ultrasound and what does it measure?\u003c\/h3\u003e\n\u003cp\u003eCarotid ultrasound is an imaging test that uses sound waves to picture the neck arteries. It measures how much atherosclerosis, or fatty plaque buildup, a person has. It can assess intima-media thickness, total plaque area, and total plaque volume. The test is rapid, reliable, and does not use radiation.\u003c\/p\u003e\n\u003ch3\u003eWhy might I need a carotid ultrasound if my risk calculator says I'm low or intermediate risk?\u003c\/h3\u003e\n\u003cp\u003eMany patients classified as low risk by standard calculators such as PROCAM and SCORE later have a first heart attack or stroke. European guidelines now suggest considering a carotid scan to refine risk estimates, especially for people in the intermediate-risk group. A scan may reveal plaque and change your true risk category.\u003c\/p\u003e\n\u003ch3\u003eHow does carotid plaque measurement compare with coronary calcium scoring?\u003c\/h3\u003e\n\u003cp\u003eCarotid plaque volume has predictive power comparable to coronary calcium scoring, but it avoids radiation exposure. In the BioImage study of 5,808 healthy subjects, carotid total plaque volume was noninferior to coronary calcium for predicting cardiovascular events in a low- to intermediate-risk population. Both approaches can help assess risk.\u003c\/p\u003e\n\u003ch3\u003eWhat is the difference between IMT and total plaque area?\u003c\/h3\u003e\n\u003cp\u003eIntima-media thickness (IMT) is the distance between the inner lining and outer supporting layer of the artery wall. Total plaque area (TPA) is the sum of the longitudinal area of all plaques in the carotid wall. Research suggests plaque measures predict heart attacks and strokes better than IMT alone.\u003c\/p\u003e\n\u003ch3\u003eCan treatment shrink carotid plaque, and how is it monitored?\u003c\/h3\u003e\n\u003cp\u003eA meta-analysis of 41 randomised trials including 18,307 participants showed active treatment significantly reduced cardiovascular events and all-cause death. However, reduction in IMT did not correlate with fewer events. Measuring plaque burden may be more useful than IMT alone when tracking whether treatment is working.\u003c\/p\u003e\n\u003ch3\u003eWhat are the limitations of carotid ultrasound?\u003c\/h3\u003e\n\u003cp\u003eThe definition of carotid plaque on ultrasound is not uniform, making study comparisons difficult. IMT measurements vary by method. Total plaque volume covers only a 3.8 cm field of view, so some plaques may be missed. Screening with atherosclerosis imaging has not received a class I recommendation in primary care.\u003c\/p\u003e\n\u003ch3\u003eWhat should I do if I have a carotid ultrasound scan?\u003c\/h3\u003e\n\u003cp\u003eIf a scan is done, focus on total plaque area, which is highly reproducible, vendor-independent, and needs no extra software. Consider femoral and aortic plaque screening where expertise allows. Track plaque presence, progression, stability, and regression over time. Continue controlling the seven modifiable risk factors with your clinician.\u003c\/p\u003e\n\u003ch3\u003eIf a risk calculator says I'm low or intermediate risk, when should I get a second opinion about a carotid ultrasound?\u003c\/h3\u003e\n\u003cp\u003eMany people who have a first heart attack or stroke were classified as low risk by standard calculators such as PROCAM and SCORE. European Joint ESC guidelines say a carotid artery scan should be considered for adjusting risk levels. This is especially true in intermediate-risk subjects. A second opinion is reasonable when a calculator places you at low or intermediate risk. A second opinion is also reasonable when you want your imaging reviewed. A second opinion is reasonable when you are deciding whether carotid plaque measurement should guide preventive treatment. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e Bonn Zurich Sonographic assessment of carotidatherosclerosis\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Romanens Michel, Sudano Isabella, Adams Ansgar, Schober Edward A.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthor affiliations:\u003c\/strong\u003e Vascular Risk Foundation, Olten, Switzerland; University Heart Centre, Cardiology Department, University Hospital Zurich, Switzerland; BAD Gesundheitsvorsorge und Sicherheitstechnik GmbH, Bonn, Germany; Fairfond Stiftung für Fairness im Gesundheitswesen, Olten, Switzerland.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication details:\u003c\/strong\u003e Swiss Medical Weekly. 2019;149:w20142. Published 17 November 2019. doi:10.4414\/smw.2019.20142. Article type: Review article (Biomedical intelligence).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e This patient-friendly article is based on peer-reviewed research. It preserves the original data, findings, and conclusions while translating technical language for a general audience. Please discuss any decisions about cardiovascular screening or treatment with your own healthcare provider.\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47415300063388,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0599\/5449\/5644\/files\/ddn-medical-article-seeing-the-problem-before-it-happens-how-carotid-ultrasound-helps-predict-heart-attacks-and-strokes-hero.png?v=1790204695","url":"https:\/\/diagnosticdetectives.com\/sv\/products\/seeing-the-problem-before-it-happens-how-carotid-ultrasound-helps-predict-heart-attacks-and-strokes","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}