The distribution of atherosclerotic lesions in the coronary arterial tree: relation to cardiac risk factors

Small Vessel Coronary Artery Disease: Rationale for Standardized Definition and Critical Appraisal of the Literature

Small vessel coronary artery disease (CAD) is present in 30% to 67% of patients undergoing percutaneous coronary intervention according to different series, representing an unmet clinical need in light of an increased risk of technical failure, restenosis, and need for repeated revascularization. The definition of small vessel is inconsistent across trials, and no definite cutoff value has yet been determined. The lack of consensus on the definition of small vessel CAD has contributed to the high degree of heterogeneity in the safety and efficacy of the various revascularization options. Therefore, the aim of this article is to provide a critical appraisal of existing reports and to propose a reference vessel diameter of <2.5 ​mm definition of small vessel CAD to guide future clinical trials and clinical decision-making.

Endothelial Barrier Function and Leukocyte Transmigration in Atherosclerosis

The vascular endothelium is a highly specialized barrier that controls passage of fluids and migration of cells from the lumen into the vessel wall. Endothelial cells assist leukocytes to extravasate and despite the variety in the specific mechanisms utilized by different leukocytes to cross different vascular beds, there is a general principle of capture, rolling, slow rolling, arrest, crawling, and ultimately diapedesis via a paracellular or transcellular route. In atherosclerosis, the barrier function of the endothelium is impaired leading to uncontrolled leukocyte extravasation and vascular leakage. This is also observed in the neovessels that grow into the atherosclerotic plaque leading to intraplaque hemorrhage and plaque destabilization. This review focuses on the vascular endothelial barrier function and the interaction between endothelial cells and leukocytes during transmigration. We will discuss the role of endothelial dysfunction, transendothelial migration of leukocytes and plaque angiogenesis in atherosclerosis.

Effects of Altered Levels of Pro- and Anti-Inflammatory Mediators on Locations of In-Stent Reocclusions in Elderly Patients

Imbalances of proatherogenic inflammatory and antiatherogenic inflammatory mediators were involved in the pathogenesis of atherosclerosis. This study sought to investigate the effects of proatherogenic inflammatory and antiatherogenic inflammatory mediators on the proximal, middle, and distal coronary artery reocclusions in elderly patients after coronary stent implantations. We measured the expression levels of proatherogenic inflammatory/antiatherogenic inflammatory cytokines. This included interleukin-1 β (IL-1 β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), high-sensitivity C-reactive protein (hs-CRP), interleukin-10 (IL-10), interleukin-17 (IL-17), interleukin-13 (IL-13), and interleukin-37 (IL-37) in the elderly patients with the proximal, middle, and distal coronary artery reocclusions after coronary stent implantations. Levels of IL-1 β, IL-6, IL-8, TNF-α, and hs-CRP were remarkably increased (P < 0.001), and levels of IL-10, IL-17, IL-13, and IL-37 were remarkably lowered (P < 0.001) in the elderly patients with the proximal, middle, and distal coronary artery reocclusions. Imbalances of proatherogenic inflammatory and antiatherogenic inflammatory mediators may be involved in the formation and progression of proximal, middle, and distal coronary artery reocclusions in elderly patients after coronary stent implantations.

Coronary artery size in North Indian population - Intravascular ultrasound-based study

Objective

The coronary artery dimensions have important diagnostic and therapeutic implications in management of coronary artery disease (CAD). There is paucity of data on the coronary artery size in the Indian population as measured by intravascular ultrasound (IVUS).

Methods

A total of 303 patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) with intravascular ultrasound underwent analysis along with quantitative coronary angiography (QCA). Of the 492 proximal coronary segments; 221 relating to left main (LM), 164 to left anterior descending artery (LAD), 45 to left circumflex artery (LCX), and 62 to right coronary artery (RCA) were considered.

Results

Patient's mean age was 53.37 ± 3.5 years; men 80%; hypertension 35% and diabetes 24.8%. On IVUS, mean minimal lumen diameter as compared to QCA in LM (4.60 mm versus 4.50 mm, p < 0.001), LAD (3.71 mm versus 3.45 mm, p < 0.001), LCX (3.55 mm versus 3.16 mm, p < 0.001) and RCA (3.85 mm versus 3.27 mm, p < 0.001) were significantly larger. Lumen and external elastic membrane (EEM) cross-sectional area (CSA) were larger in males as compared to females with statistical significance for lumen CSA in LM (p = 0.04); RCA (p = 0.02) and EEM CSA in LM (p = 0.03); RCA (p = 0.006) but no significance for adjusted body surface area (BSA). In multivariate models, BSA and age were independent predictors of LM and LAD diameters and areas, but age was an independent predictor indexed to BSA.

Conclusion

The coronary artery dimensions by IVUS are significantly larger than QCA. No gender difference in coronary artery size. Age was an independent predictor of coronary artery size in left main and LAD. The coronary artery size may not be a risk factor for acute coronary syndrome.

Optical Coherence Tomography For the Detection of the Vulnerable Plaque

Morphological characteristics of the atheromatous plaque have been associated with the development of plaque rupture and the pathogenesis of acute coronary syndromes (ACS). Plaques with a specific morphological phenotype that are at high risk of causing ACS are called vulnerable plaques, and can be identified in vivo through the use of intracoronary imaging. Optical coherence tomography (OCT) is a high-resolution intravascular imaging modality that enables detailed visualization of atheromatous plaques. Consequently, OCT is a valuable research tool for examining the role of morphological characteristics of atheromatous plaques in the progression of coronary artery disease and plaque destabilisation, which leads to the clinical manifestation of ACS. This article summarises the pathophysiological insights obtained by OCT imaging in the formation and rupture of the vulnerable plaque.

Circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 levels are associated with proximal/middle segment of the LAD lesions in patients with stable coronary artery disease

BACKGROUND/OBJECTIVES

Atherosclerosis is the main underlying pathology of coronary artery disease (CAD), which is the leading cause of mortality worldwide. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is involved in multiple phases of vascular dysfunction, including endothelial dysfunction, atherosclerotic plaque formation, and destabilization. The purpose of the current study was to determine whether soluble LOX-1 is associated with proximal/mid and distal segment of the left anterior descending (LAD) artery lesion in patients with stable CAD.

METHODS

Sixty-four patients with proximal/mid segment of the LAD lesions and 51 patients with distal segments of the LAD lesions were included in this study. Soluble LOX-1 levels were measured in all study subjects.

RESULTS

Baseline characteristics of the two groups were similar. In stable CAD, patients with proximal/middle segment of the LAD lesions had significantly higher circulating soluble LOX-1 levels than patients with distal segments of the LAD lesions (1.07 ± 0.33 vs. 0.70 ± 0.17 ng/ml, p < 0.001). No correlation was found between plasma-soluble LOX-1 levels and fasting glucose, lipid profile. For predicting proximal/middle LAD lesions, the highest specificity (95,2%) and sensitivity (53,8%) levels were obtained at the cut-off value of 0.68.

CONCLUSION

Our study demonstrated that serum-soluble LOX-1 levels were associated with proximal/mid segment of the LAD lesions. Furthermore, this study suggested soluble LOX-1 might be a useful biomarker of coronary plaque vulnerability in patients with stable CAD. Soluble LOX-1, the novel biochemical marker, may provide new insights into not only risk stratification but also therapeutic strategy for CAD.

Location of coronary culprit lesions at autopsy in 41 nondiabetic patients with acute myocardial infarction

BACKGROUND

Coronary artery disease and myocardial infarction (MI) are major causes of patient morbidity, hospital mortality, and out-of-hospital sudden death. The precise location of culprit lesions in acute MI at autopsy has not been reported.

OBJECTIVE

The purpose of this retrospective histopathologic autopsy study was to determine the distribution of coronary culprit lesions in acute fatal MI.

METHODS

Cross-sections of epicardial coronary arteries were evaluated microscopically. For each culprit lesion, its distance from the coronary ostium and its grade of luminal stenosis were recorded.

RESULTS

The study group included 41 nondiabetic patients (mean age of 65 years, 66% males) who underwent autopsy at Mayo Clinic Rochester (1994-2005). Culprit lesions occurred within the proximal 3.0 cm of the left anterior descending artery in 86% and the left circumflex artery in 100%. In contrast, culprit plaques within the right coronary artery (RCA) were distributed evenly throughout its length.

CONCLUSIONS

Among nondiabetic patients with acute fatal MI, culprit lesions exhibited proximal clustering in the left anterior descending artery and left circumflex artery, in contrast to more uniform distribution in the RCA. Thus, for the autopsy investigation of sudden death, evaluation for culprit lesions in the entire length of the RCA, not just its proximal region, is recommended.

Relation of coronary artery plaque location to extent of coronary artery disease studied by computed tomographic angiography

BACKGROUND

Distal coronary artery disease (CAD) is less amenable to surgery or stenting compared with proximal disease. However, little is known about the epidemiology of distal versus proximal CAD.

METHODS

We determined the prevalence and factors associated with proximal, mid, and distally located plaque in the left anterior descending, left circumflex, and right coronary arteries in 418 subjects without prior CAD history who underwent coronary computed tomographic angiography for symptoms or stress test results. Clinical characteristics and coronary artery calcium (CAC) scores were also determined.

RESULTS

Most subjects (88%) had plaque, but only 18% of plaques were associated with stenosis >50%. In subjects with single-vessel plaque, only 7% had distal plaque, whereas 75% had proximal plaque. With 3-vessel plaque, 70% had distal and 100% had proximal plaques. Of subjects with a single location of plaque along a vessel, most had proximal plaque (69%); isolated distal-vessel plaque was rare (2%). Distal plaque was dominantly found in association with both proximal and mid plaque (88%). After multivariable adjustment for demographics, traditional, and nontraditional risk factors, both increasing number of vessels with plaque and clinically significant CAC scores were independently associated with higher odds of distal plaque, whereas associations of traditional risk factors were weaker. Distal plaque was independently associated with stenosis > 50%.

CONCLUSION

These data support the concept that early lesions are most often proximal and that CAC scoring may be a poor screening tool for detecting proximal disease. Furthermore, distal lesions are more associated with advanced disease than with traditional cardiovascular risk factors.

Computed tomography coronary angiography plaque burden in patients with suspected coronary artery disease

PURPOSE

To determine the relationship between established cardiovascular risk factors, clinical presentation and the extent of coronary artery disease (CAD), as described with computed tomography coronary angiography.

MATERIAL AND METHODS

In this cross-sectional study, we included 567 symptomatic individuals without a history of CAD who consecutively underwent 64-slice computed tomography coronary angiography for evaluation of suspected CAD. We analyzed the prevalence of CAD depending on sex, age, symptoms and risk factors.

RESULTS

A total of 8542 segments were analyzed. No evidence of CAD was observed in 225 patients (40%), nonsignificant CAD in 221 patients (39%) and significant CAD (luminal narrowing >50%) in the remaining 121 patients (21%). CAD increased with advancing age, significantly above 50 years (P < 0.05). Female patients had a higher prevalence of normal coronary arteries and males of significant CAD (P < 0.01). With the increase of risk factors, there was a significant increase of the significant disease (P < 0.01). Typical pain with respect to atypical pain had the strongest association with significant CAD (16 vs. 38%; P < 0.05). In multivariate analysis, the number of risk factors, age, male sex and typical pain remained strong predictors of significant CAD (P < 0.0001).

CONCLUSION

Computed tomography coronary angiography may play an important role in risk stratification of patients with suspected CAD.

High echogenic thickening of proximal coronary artery predicts the far advanced coronary atherosclerosis

BACKGROUND

Detection of subclinical, nonobstructive coronary artery disease will require the evaluation of coronary arterial walls and external coronary diameter in order to detect increases in arterial wall thickness and compensatory remodeling before luminal narrowing. We assessed the meaning of high echogenic thickening (HET) on transthoracic coronary echogram of proximal coronary arteries and evaluated whether HET predicts the severity of coronary artery disease on angiogram.

METHODS

Ninety-seven patients (M:F = 61:36, mean age = 61+/-8 years) referred for coronary angiography were included in this study. We detected proximal coronary artery using transthoracic coronary echogram. We defined that HET is more than 1.5 mm in thickness with high echogenicity and persistence. Of these patients, 29 vessels were examined by IVUS (intravascular ultrasound).

RESULTS

(1) HET on coronary echogram had a sensitivity of 44.4% and specificity of 95% for identifying calcification on IVUS. (2) HET had a sensitivity of 73.5% and specificity of 85.7% for identifying the significant stenosis of proximal left coronary artery. (3) HET was observed more frequently in three-vessel diseases and more complex lesion compared to normal and one- or two-vessel diseases (P < 0.05, respectively).

CONCLUSION

HET may be related to the presence of calcification and predicts far advanced coronary atherosclerosis.

Coronary atherosclerotic lesions in human immunodeficiency virus-infected patients: a histopathologic study

BACKGROUND

Studies suggest human immunodeficiency virus-positive (HIV+) patients have an increased risk of coronary artery disease (CAD), yet little is known about the histopathology, severity, or distribution of lesions.

METHODS

The coronary arteries of 66 deceased AIDS patients and 19 HIV controls (age <55) were dissected and graded for percent luminal stenosis by intimal lesions, percent of intima involved with lipid, and extent of intimal calcification on a scale of 0 to 3. Medical histories, antiretroviral therapies, and CAD risk factors were reviewed.

RESULTS

HIV+ patients were older than controls (P=.06), and more were male (P=.02). Thirty-five percent of HIV+ patients had stenosis >or=75% of at least one artery. Compared to controls, HIV+ patients had three times greater odds of stenosis >or=75%, controlling for age and sex (one-sided P=.03). Older age and male sex were also risk factors (one-sided P<.001). HIV seropositivity was associated with increased plaque lipid content (one-sided P=.02) and calcification (one-sided P=.08). Duration of HIV infection, antiretroviral therapy, and immune status did not predict severe disease in multivariate analyses. Previously unreported patterns of dystrophic calcification were observed in HIV+ patients and older controls.

CONCLUSIONS

Young to middle-aged patients dying from advanced AIDS have atherosclerotic CAD that may result in luminal narrowing, heavy calcification, and high plaque lipid content. The pattern of disease, location of lesions, and plaque composition are typical of atherosclerosis in HIV-negative patients. No relationship between antiretroviral therapies and atherosclerosis was seen in this small study of heavily treated patients.

Anatomic characteristics of culprit sites in acute coronary syndromes

BACKGROUND

A detailed analysis of the anatomic relationships of the site of culprit lesions that have resulted in acute coronary syndromes (ACS) has not been reported.

METHODS

Coronary angiograms of consecutive patients who presented with ACS were analyzed according to multiple anatomic criteria.

RESULTS

In left anterior descending artery (LAD) (n = 85), 85% of culprit lesions were located in the first 40 mm from the ostium. The presence of angulation on the lesion increased the risk of an ACS 1.92 times (95% confidence interval [CI] 1.9-3.07), and the presence of bifurcation after the lesion increased the risk 1.65 times (95% CI 1.04-2.62). Angulated lesions located within the first 40 mm from the ostium and before a bifurcation presented an 11-fold increased risk for an ACS. In right coronary artery (RCA) (n = 58), the risk of plaque rupture was almost 2.5 times higher in lesions located between 10 and 50 mm from the ostium compared to those located in 90-130 mm (relative risk [RR] 2.38, 95% CI 1.25-4.56). In left circumflex (LCx) (n = 40), the risk of plaque rupture was almost 4.5 and 5 times higher in the first 20 mm, and between 20 and 40 mm from the ostium, respectively, compared to 60 and 80 mm (relative risk [RR] 4.58, 95% CI 1.01-20.68 for 0-20 mm, and RR 4.95, 95% CI 1.14-21.47 for 20-40 mm) after adjustment for the presence of curve on the lesion. The presence of lesion angulation increased the risk of plaque rupture almost three times (RR 3.22, 95% CI 1.49-6.93).

CONCLUSION

Specific anatomic features of the coronary arteries predispose to development and/or subsequent rupture of vulnerable plaques.

Large and Small Vessels Atherosclerosis: Similarities and Differences

Atherosclerosis is a systemic, multifocal disease leading to a various symptoms and clinical events. Beyond disparities related to the organs involved, some differences might exist according to whether the lesions occur in the large (proximal) or small (distal) arteries. Atherosclerotic lesions occur predominantly in the large vessels first, and more distal lesions occur with aging. Proximal lesions are usually more evolving, especially with higher rates of unstable plaques in the proximal segments of coronary arteries. Racial differences regarding lesion distribution exist, with higher rates of distal lesions observed in races other than caucaians. Despite conflicting results found in each vascular territory, there is a suggestion of a stronger association between large vessel disease and smoking and dyslipidemia, whereas diabetes appears more specific for small vessel disease. Hypertension is more frequently reported in intracranial than in extracranial cerebrovascular disease. Preliminary studies report inflammatory markers preferably associated to large-vessel atherosclerosis. Proximal lesions in 1 territory are more frequently associated with concomitant lesions in other territories. Geometric, hemodynamic, and histologic particularities in large and small vessels may at least partially explain these differences, and some recent data point out different biologic properties of the endothelium according to its location.

Hemodynamic factors and atheromatic plaque rupture in the coronary arteries: from vulnerable plaque to vulnerable coronary segment

Coronary plaque disruption with superimposed thrombosis is the underlying pathology in the acute coronary syndromes and sudden death. Coronary plaques are constantly stressed by a variety of mechanical and hemodynamic forces that may precipitate or 'trigger' disruption of vulnerable or, at extreme conditions, even stable plaques. This paper reviews the exciting new evidence on the hemodynamic factors that may play a role in this process and provides the rationale for the introduction of the concept of the vulnerable coronary segment in the study of acute coronary syndromes.

Plaque Composition in the Left Main Stem Mimics the Distal But Not the Proximal Tract of the Left Coronary Artery

OBJECTIVES

We sought to investigate whether plaques located in the left main stem (LMS) differ in terms of necrotic core content from those sited in the proximal tract of the left coronary artery.

BACKGROUND

Plaque composition, favoring propensity to vulnerability, might be nonuniformly distributed along the vessel, which might explain the greater likelihood for plaque erosion or rupture to occur in the proximal but not in the distal tracts of the coronary artery or in LMS.

METHODS

A total of 72 patients were included prospectively; 48 (32 men; mean age 57 +/- 11 years; 25 with stable angina and 23 affected by acute coronary syndromes) underwent a satisfactory nonculprit vessel investigation through spectral analysis of intravascular ultrasound radiofrequency data (IVUS-Virtual Histology, Volcano Corp., Rancho Cordova, California). The region of interest was subsequently divided into LMS and LMS carina, followed by 6 consecutive nonoverlapping 6-mm segments in left anterior descending artery in 34 patients or in circumflex artery in 14 patients.

RESULTS

Necrotic core content (%): 1) was minimal in LMS (median [interquartile range]: 4.6 [2 to 7]), peaked in the first 6-mm coronary segment (11.8 [8 to 16]; p < 0.01), and then progressively decreased distally; 2) was overall greater in patients with acute coronary syndromes (11.4 [5.5 to 19.8]) than stable angina (7.3 [3.2 to 12.9]; p < 0.001); 3) was largely independent from plaque size; and 4) did not correlate to systemic levels of C-reactive protein or lipid profile.

CONCLUSIONS

Plaques located in the LMS carry minimal necrotic content. Thus, they mimic the distal but not the proximal tract of the left coronary artery, where plaque rupture or vessel occlusion occurs more frequently.

Are complex coronary lesions more frequent in patients with diabetes mellitus?

BACKGROUND

Coronary atherosclerotic burden is excessive in diabetic patients. Diabetes mellitus (DM) is an independent predictor for both death and myocardial infarction. It is not known whether the prevalence of complex coronary lesions, such as bifurcation and ostial lesions, is different in diabetics from nondiabetics.

OBJECTIVE

The aim of present study was to investigate the prevalence of these lesions in patients with DM.

METHODS

One thousand fourteen consecutive patients (mean age 61.3+/-10.7 years) were investigated. Coronary angiograms were examined for bifurcation and ostial lesions using a digital quantitative system. Patients were classified as diabetic (n=281) or nondiabetic (n=733).

RESULTS

Patient mean age, and rates of hypertension and hyperlipidemia were significantly higher in the diabetic group than in the nondiabetic group (P<0.0001), although smoking was significantly lower (P=0.001). Reasons for coronary angiography and treatment were comparable between the two groups. The prevalence of bifurcation lesions and ostial lesions was significantly greater in the diabetic group than in the nondiabetic group (9.8% versus 4.3% [P=0.001] and 38.4% versus 29.2% [P=0.003] in the diabetic group versus the nondiabetic group). The presence of DM and greater age were found to be independent predictors for bifurcation lesions (OR=2.27 [P=0.004] and OR=1.03 [P=0.01], for DM and age, respectively) and ostial lesions (OR=1.40 [P=0.027] and OR=1.02 [P=0.001], for DM and age, respectively) in multivariate analysis.

CONCLUSIONS

Complex coronary lesions such as bifurcation and ostial lesions were significantly more common in diabetic patients than in nondiabetic patients. Greater age and the presence of DM were independent predictors for these complex lesions. These results may help to explain the poor prognosis of coronary artery disease among diabetic patients.

Intravascular ultrasound assessment of the spatial distribution of ruptured coronary plaques in the left anterior descending coronary artery

BACKGROUND

Plaque rupture is a substrate for thrombosis, occlusion, and myocardial infarction. The left anterior descending coronary artery (LAD) subtends the largest amount of myocardium; therefore, the location of LAD plaque rupture is of particular importance in detecting vulnerable plaques. The aim of our study was to assess the location of ruptured atherosclerotic plaques in the LAD.

METHODS

Using intravascular ultrasound, we detected 160 ruptured LAD plaques. Of these, accurate intravascular ultrasound distance measurements (with consistent automatic transducer pullback [0.5 mm/s] to the LAD ostium) could be determined in 112 ruptured plaques.

RESULTS

There were 104 patients (91 men, age 63.8 +/- 11.7 years). The total length of the LAD that was imaged measured 48.8 +/- 24.8 mm. The distance from the LAD origin to the maximal plaque cavity was 16.2 +/- 10.3 mm; the maximal plaque cavity was localized to the first 20 mm of the LAD in 71% and the first 30 mm in 88%. Only 2 ruptured plaques were found beyond 40 mm from the LAD ostium.

CONCLUSIONS

The majority of LAD ruptured plaques are located within the proximal 30 mm of the artery. This area of the LAD should be targeted for vulnerable (rupture-prone) plaque detection and prevention.

Anatomy of coronary disease in diabetic patients: an explanation for poorer outcomes after percutaneous coronary intervention and potential target for intervention

There are over 1.3 million known diabetic patients in the UK and a similar number who have the disease undiagnosed. Over 90% have non-insulin dependent diabetes mellitus usually characterised by insulin resistance and adult onset. Over half of all diabetic patients die of coronary disease and account for over a fifth of percutaneous coronary intervention (PCI) revascularisation procedures. Despite recent therapeutic advances such as new antiplatelet treatments and drug eluting stents, outcomes for diabetic patients after PCI are still significantly worse than for non-diabetic patients. This article summarises what is known about the pattern and severity of diabetic coronary disease, what mechanisms are responsible for these differences, and whether this information can help explain the poorer prognosis for these patients after PCI and form the basis of interventions to improve outcome.

Multislice computed tomography of the coronary arteries

Multislice spiral CT (MSCT) of the coronary arteries is developing rapidly as a noninvasive method for assessing coronary artery anatomy and for calculating various parameters of cardiac function. This article reviews the issues involved in MSCT coronary angiography and the methods used to overcome them. The current clinical applications for MSCT coronary angiography are summarized with reference to published clinical studies. The capabilities of CT are compared with those of MRI. Both modalities have a wide range of indications in the noninvasive diagnostic assessment of the heart and partly overlap in their clinical application.

The assessment of the vulnerable atherosclerotic plaque using MR imaging: a brief review

The study of atherosclerotic disease during its natural history and after therapeutic intervention may enhance our understanding of the progression and regression of this disease and will aid in selecting the appropriate medical treatments or surgical interventions. Several invasive and non-invasive imaging techniques are available to assess atherosclerotic disease vessels. Most of these techniques are strong in identifying the morphological features of the disease such as lumenal diameter and stenosis or wall thickness, and in some cases provide an assessment of the relative risk associated with the atherosclerotic disease. However, none of these techniques can fully characterize the composition of the atherosclerotic plaque in the vessel wall and therefore are incapable of identifying the vulnerable plaques. High-resolution, multi-contrast, magnetic resonance (MR) can non-invasively image vulnerable plaques and characterize plaques in terms of lipid and fibrous content and identify the presence of thrombus or calcium. Application of MR imaging opens up whole new areas for diagnosis, prevention, and treatment of atherosclerosis.

Angiographic severity and extent of coronary artery disease in patients with type 1 diabetes mellitus

Studies of the characteristics of coronary artery disease (CAD) in diabetic patients have shown conflicting results. Only 2 studies exploring the severity of CAD, specifically in type 1 diabetes, have been published, and neither of them has used computer-aided quantitative coronary angiography. This retrospective study comprised 64 (24 women and 40 men) type 1 diabetic patients and nondiabetic control subjects. To estimate the severity, extent, and overall "atheroma burden" of CAD, we used quantitative coronary angiographic-based segmental analysis of coronary angiograms. Type 1 diabetic patients had greater global severity (p < 0.001), global extent (p < 0.001), and global atheroma burden (p < 0.001) indexes than nondiabetic control subjects. Quantitative coronary angiographic-derived indexes of CAD were, on average, 1.4- to 4.3-fold higher in diabetic than in nondiabetic patients. These differences were particularly marked in women. We found that type 1 diabetic patients with a clinical indication for coronary angiography, especially women, have more severe, extensive, and distal type of CAD than individually matched nondiabetic control patients. Our findings, including a loss of sex difference for CAD among type 1 diabetic patients and a marked impact of type 1 diabetes in women, are not explained by established risk factors.

Noninvasive in vivo human coronary artery lumen and wall imaging using black-blood magnetic resonance imaging

BACKGROUND

High-resolution MRI has the potential to noninvasively image the human coronary artery wall and define the degree and nature of coronary artery disease. Coronary artery imaging by MR has been limited by artifacts related to blood flow and motion and by low spatial resolution.

METHODS AND RESULTS

We used a noninvasive black-blood (BB) MRI (BB-MR) method, free of motion and blood-flow artifacts, for high-resolution (down to 0.46 mm in-plane resolution and 3-mm slice thickness) imaging of the coronary artery lumen and wall. In vivo BB-MR of both normal and atherosclerotic human coronary arteries was performed in 13 subjects: 8 normal subjects and 5 patients with coronary artery disease. The average coronary wall thickness for each cross-sectional image was 0.75+/-0.17 mm (range, 0.55 to 1.0 mm) in the normal subjects. MR images of coronary arteries in patients with >/=40% stenosis as assessed by x-ray angiography showed localized wall thickness of 4.38+/-0.71 mm (range, 3.30 to 5.73 mm). The difference in maximum wall thickness between the normal subjects and patients was statistically significant (P<0.0001).

CONCLUSIONS

In vivo high-spatial-resolution BB-MR provides a unique new method to noninvasively image and assess the morphological features of human coronary arteries. This may allow the identification of atherosclerotic disease before it is symptomatic. Further studies are necessary to identify the different plaque components and to assess lesions in asymptomatic patients and their outcomes.

Quantitative comparison of angiographic characteristics of coronary artery disease in patients with noninsulin-dependent diabetes mellitus compared with matched nondiabetic control subjects

The angiographic characteristics of coronary artery disease (CAD) in noninsulin-dependent diabetes mellitus (NIDDM) patients were studied by quantitative coronary angiography (QCA). Fifty-seven consecutive NIDDM patients undergoing clinically indicated elective coronary angiography and 57 nondiabetic coronary artery disease (CAD) patients were individually matched for sex, age, and body mass index. Technically adequate coronary angiograms, available for 55 subjects in each group, were analyzed with third-generation QCA software. To evaluate the anatomic severity and extent of CAD, several QCA-derived parameters were incorporated into indexes describing various per-patient features of CAD. These measures reflect CAD severity, extent, and overall "atheroma burden," and were calculated separately for different coronary segments (i.e., left main, proximal, mid, and distal segments), for the different coronary arterial territories (i.e., left main, left anterior descending, left circumflex, and right), and for the entire coronary tree. No significant differences were found between the NIDDM and nondiabetic groups (global severity index, 51 +/- 14 vs 54 +/- 13, p = NS; global extent index, 34 +/- 13 vs 32 +/- 12, p = NS; global atheroma burden index, 27 +/- 16 vs 24 +/- 12, p = NS). We also found no between-group differences in proximal, mid, or distal segments, in separate vessel territories, or in left ventricular function. Our data suggest that CAD patients, with and without NIDDM, who have similar symptoms at a given age, have similar severity and extent of CAD.

Transthoracic echocardiographic detection of coronary atherosclerosis

Coronary atherosclerosis is a pathologic process that produces thickening of the walls of the coronary arteries to the point that flow through those vessels may be impaired. This study attempts to use transthoracic echocardiography to detect coronary atherosclerosis. Eighty-nine patients undergoing coronary angiography were examined with a broad-band ultrasonic transducer with a frequency between 3 and 5 MHz. A modified short axis examination was utilized to identify left main and proximal left anterior descending arteries. The examination was recorded digitally and displayed in a 32-cell, quad screen cine loop. Fifty-six of the 89 patients (63%) had obstructive coronary artery disease (CAD) (i.e, at least 1 vessel with 50% obstruction). There were 14 patients with CAD but no vessel had > or = 50% obstruction. Nineteen patients (21%) had angiographically normal arteries. The coronary echograms were judged qualitatively for brightness, uniformity, and persistence (defined as the ability to see segments of the artery walls in more frames than other segments). The length of the coronary artery visualized, the width of the left main coronary artery, and the width of the thickest segment of the coronary artery walls were quantitatively measured. More than 2 cm of the left coronary artery was seen in almost all patients. Segmental changes were noted in 52 of the 56 patients with obstructive CAD, 12 of the 14 patients with nonobstructive CAD, and 3 of the 19 patients with normal arteries. Persistence greatly enhanced the ability to judge the segmental changes. Forty-six patients with obstructive disease had wall thickness > or = 1.5 mm. Only 6 patients with nonobstructive coronary arteries had this wall thickness, and only 1 normal subject had thick walls. The ultrasonic findings were useful in predicting the presence or absence of coronary atherosclerosis to varying degrees of sensitivity and specificity based on the segmental findings and wall thickness measurements. The results of this study indicate that a transthoracic ultrasonic examination of the proximal left coronary artery could be a clinically valuable tool in the qualitative identification of coronary atherosclerosis.