Plaque volume,composition, and fraction versus ischemia and outcomes in patients with coronary artery disease

BackgroundThe various plaque components have been associated with ischemia and outcomes in patients with coronary artery disease (CAD). The main goal of this analysis was to test the hypothesis that, at patient level, the fraction of non-calcified plaque volume (PV) of total PV is associated with ischemia and outcomes in patients with CAD. This ratio could be a simple and clinically useful parameter, if predicting outcomes.MethodsConsecutive patients with suspected CAD undergoing coronary computed tomography angiography with selective positron emission tomography perfusion imaging were selected. Plaque components were quantitatively analyzed at patient level. The fraction of various plaque components were expressed as percentage of total PV and examined among patients with non-obstructive CAD, suspected stenosis with normal perfusion, and those with reduced myocardial perfusion. Clinical outcomes included all-cause mortality and myocardial infarction.ResultsIn total, 494 patients (age 63 ​± ​9 years, 55% male) were included. Total PV and all plaque components were significantly larger in patients with reduced myocardial perfusion compared to patients with normal perfusion and those with non-obstructive CAD. During follow-up 35 events occurred. Patients with any plaque component ​≥ ​median showed worse outcomes (log-rank p ​< ​0.001 for all). In addition, low-attenuation plaque ​≥ ​median was associated with worse outcomes independent of total PV (adjusted HR: 2.754, 95% CI: 1.022–7.0419, p ​= ​0.045). The fractions of the various plaque components were not associated with outcomes.ConclusionLarger total PV or any plaque component at patient level are associated with abnormal myocardial perfusion and adverse events. The various plaque components as fraction of total PV lack additional prognostic value.     

Potential utility of rubidium 82 pet quantification in patients with 3-vessel coronary artery disease

BACKGROUND: Standard perfusion imaging may underestimate the extent of disease in 3-vessel coronary atherosclerosis. This study determined whether positron emission tomography quantification of perfusion reserve by use of rubidium 82 net retention defined a greater extent of disease than the standard approach in patients with 3-vessel disease. METHODS AND RESULTS: Rb-82 net retention was quantified as an estimation of absolute perfusion at rest and with dipyridamole stress by use of dynamic positron emission tomography imaging. The percent of abnormal myocardial sectors, as compared with a normal database, for a standard and quantification approach was determined. Twenty-three patients were evaluated. Defect sizes were larger in patients with 3-vessel disease (n = 13) by use of quantification methods: 44% +/- 18% of the myocardial sectors were abnormal by use of the standard approach versus 69% +/- 24% of sectors when measured by quantification of the stress-rest perfusion difference (P =.008). In patients with single-vessel disease (n = 10), defect sizes were smaller with quantification methods. CONCLUSIONS: Quantification of Rb-82 net retention to measure the stress-rest perfusion difference in the myocardium defined a greater extent of disease than the standard approach in this group of patients with triple-vessel disease. More accurate measurement of the extent of coronary artery disease could facilitate better risk stratification and identify more high-risk patients in whom aggressive intervention is required.     

腺苷负荷99mTc-MIBI心肌SPECT/CT显像诊断冠心病及检测存活心肌的研究

 目的 评价国产腺苷负荷心肌灌注断层显像对心肌缺血的诊断及腺苷试验的安全性.方法 60例临床疑似冠心病的患者行腺苷负荷99mTc-MIBI(甲氧基异丁基异腈)心肌灌注断层显像,其中40例行冠脉造影检查.腺苷按0.84 mg/kg通过输液泵静脉双通路给药,对心肌灌注显像图作定性分析.结果 60例患者行冠脉造影者40例,其中正常8例,1支以上狭窄≥50%者32例,其中病变为单支11例,双支14例,3支7例.60例行腺苷负荷心肌灌注显像检查总阳性率为80%(48/60).腺苷试验不良反应轻时间短,发生率为80%(48/60).结论 腺苷负荷心肌灌注显像安全可靠.     

Multislice CT angiography assessment of left coronary artery: correlation between bifurcation angle and dimensions and development of coronary artery disease

Purpose

To investigate the relationship between left coronary bifurcation and dimensional changes and development of coronary artery disease using multislice CT angiography.

Materials and methods

30 patients (18 men, 12 women, mean age, 56 years ± 8) suspected of coronary artery disease undergoing 64- and 256-slice CT angiography were included in the study. Left bifurcation angle and left coronary diameter were measured to determine the relationship between angulation and plaque formation and subsequent dimensional changes.

Results

Plaques were present in the left coronary artery in 22 patients with variable angulations and dimensional changes. The mean bifurcation angle between left anterior descending and left circumflex arteries was measured 89.1° ± 13.1° (range, 55.3°, 134.5°) among all patients. The mean bifurcation angle measured in patients with normal and diseased left coronary artery was 75.5° ± 19.8° (range, 60°, 96.1°), and 94° ± 19.7° (range, 55.3°, 134.5°), respectively, with significant difference between these two groups (p = 0.02). Similarly, there is a significant difference in the mean diameters of left anterior descending and left circumflex between patients with normal and diseased left coronary artery (p < 0.001), which were measured 2.8 ± 0.3 mm (range, 2.2, 3.2 mm) and 2.1 ± 0.4 mm (range, 1.9, 2.9 mm) for the normal left coronary arteries, 4.0 ± 0.8 mm (range, 2.5, 6.1 mm) and 2.9 ± 0.5 mm (range, 1.6, 3.9 mm) for the diseased left coronary arteries, respectively.

Conclusion

There is a direct correlation between left bifurcation angle and dimensional changes and formation of plaques. Multislice CT angiography can be used to provide relevant features of left coronary atherosclerosis.     

Relation of coronary vasoreactivity and coronary calcification in asymptomatic subjects with a family history of premature coronary artery disease

Electron-beam computed tomography (EBCT) allows non-invasive imaging of coronary calcification and has been promoted as a screening tool for coronary artery disease (CAD) in asymptomatic high-risk subjects. This study assessed the relation of coronary calcifications to alterations in coronary vascular reactivity by means of positron emission tomography (PET) in asymptomatic subjects with a familial history of premature CAD. Twenty-one subjects (mean age 51±10 years) underwent EBCT imaging for coronary calcifications expressed as the coronary calcium score (CCS according to Agatston) and rest/adenosine-stress nitrogen-13 ammonia PET with quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR). The mean CCS was 237±256 (median 146, range 0–915). The CCS was <100 in eight subjects and >100 units in 13. As defined by age-related thresholds, 15 subjects had an increased CCS (>75th percentile). Overall mean resting and stress MBF and CFR were 71±16 ml 100 g^–1 min^–1, 218±54 ml 100 g^–1 min^–1 and 3.20±0.77, respectively. Three subjects with CCS ranging from 114 to 451 units had an abnormal CFR (<2.5). There was no relation between CCS and resting or stress MBF or CFR (r=0.17, 0.18 and 0.10, respectively). In asymptomatic subjects a pathological CCS was five times more prevalent than an abnormal CFR. The absence of any close relationship between CCS and CFR reflects the fact that quantitative myocardial perfusion imaging with PET characterises the dynamic process of vascular reactivity while EBCT is a measure of more stable calcified lesions in the arterial wall whose presence is closely related to age.     

Smoking and obesity predict high-risk plaque by coronary CTA in low coronary artery calcium score (CACS)

BackgroundThe AHA recommends statins in patients with CACS>100 AU. However in patients with low CACS (1–99 AU), no clear statement is provided, leaving the clinician in a grey-zone. High-risk plaque (HRP) criteria by coronary CTA are novel imaging biomarkers indicating a higher a-priori cardiovascular (CV) risk, which could help for decision-making. Therefore the objective of our study was to identify which CV-risk factors predict HRP in patients with low CACS 1–99.Methods1003 symptomatic patients with low-to-intermediate risk, a clinical indication for coronary computed tomography angiography (CCTA) and who had a coronary artery calcium score (CACS) between 1 and 99 AU, were enrolled. CCTA analysis included: stenosis severity and HRP-criteria: low-attenuation plaque (LAP <30HU, <60HU and <90HU) napkin-ring-sign, spotty calcification and positive remodeling. Multivariate regression models were created for predicting HRP-criteria by the major 5 cardiovascular risk factors (CVRF) (smoking, arterial hypertension, positive family history, dyslipidemia, diabetes) and obesity (BMI>25 ​kg/m²).Results304 (33.5%) were smokers. 20.4% of smokers had HRP compared with only 14.9% of non-smokers (p ​= ​0.045). Male gender was associated with HRP (p ​< ​0.001).Smoking but not the other 5 CVRF had the most associations with HRP-criteria (LAP<60HU/≥2 criteria:OR 1.59; 95%CI:1.07–2.35), LAP<90HU (OR 1.57; 95%CI:1.01–2.43), Napkin-Ring-Sign (OR 1.78; 95%CI:1.02–3.1) and positive remodelling (OR 1.54; 95%CI:1.09–2.19). Smoking predicted fibrofatty LAP<90HU in males only. Obesity predicted LAP<60HU in both females and males.ConclusionsIn patients with low CACS 1-99AU, male gender, smoking and obesity, but not the other CVRF predict HRP. These patients would rather benefit from intensification of primary CV-prevention measures such as statins.     

Non-invasive assessment of coronary artery geometry using coronary CTA

AimTo assess the association of coronary artery geometry with the severity of coronary artery disease (CAD).Methods73 asymptomatic individuals at increased risk of CAD due to peripheral vascular disease (18 women, mean age 63.5 ± 8.2 years) underwent coronary computed tomography angiography (coronary CTA) using first generation dual-source CT. Curvature and tortuosity of the coronary arteries were quantified using semi-automatically generated centerlines. Measurements were performed for individual segments and for the entire artery. Coronary segments were labeled according to the presence of significant stenosis, defined as >70% luminal narrowing, and the presence of plaque. Comparisons were made by segment and by artery, using linear mixed models.ResultsOverall, median curvature and tortuosity were, respectively, 0.094 [0.071; 0.120] and 1.080 [1.040; 1.120] on a per-segment level, and 0.096 [0.078; 0.118] and 1.175 [1.090; 1.420] on a per-artery level. Curvature was associated with significant stenosis at a per-segment (p < 0.001) and per-artery level (p = 0.002). Curvature was 16.7% higher for segments with stenosis, and 13.8% higher for arteries with stenosis. Tortuosity was associated with significant stenosis only at the per-segment level (p = 0.002). Curvature was related to the presence of plaque at the per-segment (p < 0.001) and per-artery level (p < 0.001), tortuosity was only related to plaque at the per-segment level (p < 0.001).ConclusionCoronary artery geometry as derived from coronary CTA is related to the presence of plaque and significant stenosis.     

Detecting and assessing severity of coronary artery disease in humans

Quantitation of stenosis severity has become an essential part of cardiac diagnosis and therapy, not only in research but also in clinical practice. Since our introduction of the concept 15 years ago, arterial coronary flow reserve for assessing effects of coronary narrowing has evolved into two independent but complementary measurements: coronary flow reserve and stenosis flow reserve. Coronary artery flow reserve and/or myocardial perfusion reserve takes into account not only stenosis geometry but also collateral function and physiologic conditions of perfusion pressure, vasomotor tone, coronary venous pressure, and myocardial vascular bed size. Coronary artery flow reserve is measured invasively by flowmeter or by Doppler catheter. Its noninvasive equivalent is myocardial perfusion reserve, assessed by myocardial perfusion imaging with positron emission tomography before and after intravenous dipyridamole with hand grip stress. Both have been experimentally and clinically validated for identifying and/or quantifying severity of coronary artery disease. By either invasive or noninvasive methods, coronary artery or myocardial perfusion reserve may be subcategorized as either absolute flow or perfusion reserve (max flow/resting flow) and/or relative flow or perfusion reserve (max flow through stenotic artery/max flow through normal artery). Absolute flow reserve depends not only on stenosis severity but also on unrelated physiologic parameters such as aortic pressure and the vasodilatory state of the distal coronary vascular bed; in contrast, relative flow reserve is independent of these physiologic variables and reflects stenosis severity alone. Stenosis flow reserve is invasively determined by automated, quantitative coronary arteriography accounting for all stenosis dimensions and is independent of ambient physiologic conditions such as pressure, vasomotor tone, or other variables affecting the distal coronary vascular bed. It has also been validated experimentally, tested clinically, and is applicable to cine x-ray film-based systems or to on-line digital angiographic cath lab facilities for quantifying effects of therapeutic interventions. Both functional and anatomic measurements are necessary to completely define stenosis severity. Of noninvasive functional approaches for assessing stenosis severity, cardiac positron emission tomography (PET) is the optimum for assessing relative and absolute myocardial perfusion reserve. Of the invasive anatomic approaches, quantitative coronary arteriography is the optimum for determining stenosis flow reserve from all stenosis dimensions under standard conditions.     

阿托伐他汀对冠心病患者肱动脉内皮依赖性舒张功能的影响

目的：应用高频超声观察冠心病（CAD）患者，经阿托伐他汀治疗后对肱动脉内皮依赖性舒张功能（EDD）的改善作用。方法：经冠脉造影（CAG）确诊为CAD患者59例，利用高频超声血管技术检测阿托伐他汀对CAD患者治疗前后肱动脉EDD的疗效。结果：阿托伐他汀治疗2年后，EDD比治疗前有明显改善（P〈0．05），与对照组相比无显著性差异（P〉0．05）。常规治疗组治疗2年后，EDD无明显改善（P〉0．05），与阿托伐他汀组治疗后及对照组相比差异有显著性（P〈0．05）。结论：阿托伐他汀具有改善EDD的作用。     

Comparison of thallium-201 single-photon emission tomography after rest injection and fluorodeoxyglucose positron emission tomography for assessment of myocardial viability in patients with chronic coronary artery disease

This prospective study in 42 patients with chronic coronary artery disease and severe wall motion abnormalities (sWMA) on cineventriculography (24 patients with previous myocardial infarction; ejection fraction, 45%±13%) was designed to compare myocardial thallium-201 uptake after rest injection and normalized fluorodeoxyglucose (¹⁸FDG) uptake (after oral glucose load) for assessment of a rest ²⁰¹Tl protocol to evaluate myocardial viability. The left ventricle was divided into the supply territory of the left anterior descending coronary artery (LAD) and the lateral wall and posterior territory (inferior, posterior and posteroseptal segments) because of the high variability of left circumflex and right coronary artery supply territories. Segmental ²⁰¹Tl uptake in single-photon emission tomography (SPET) and segmental normalized ¹⁸FDG uptake (13 segments per patient) showed a close linear relationship in the LAD territory (r=0.79) and in the lateral wall (r=0.77), while the correlation in the posterior territory was considerably lower (r=0.52). ²⁰¹Tl/¹⁸FDG concordance was defined as an ¹⁸FDG uptake exceeding ²⁰¹Tl uptake by < 20%. Discordance was assumed if ¹⁸FDG exceeded ²⁰¹Tl uptake by at least 20%. Concordant results were shown by 81% (439/541) of segments. In segments with severe ²⁰¹Tl reduction ( 50% of peak, n=78) discordance was observed in 10% of segments in the LAD territory and lateral wall (n=62) and in 44% of segments in the posterior territory (n=16). In segments with moderate ²⁰¹Tl reduction (51%–75%, n=205) discordance occured in 12% (LAD and lateral wall, n=126) or 46% (posterior territory, n=79) of segments, respectively. Severe defects were defined as the entire area with ²⁰¹Tl uptake 50% within a defined territory. Discordance was observed in 6/43 (14%) of these. Of 90 areas with sWMA on cineventriculography, 12 showed discordant results. Ten of these 12 discordant areas affected septum or posterior wall. In areas with normal wall motion or only mild hypokinesis, discordance occured in the septum or posterior wall in 22% whereas the figure for the anterior or lateral wall was only 2%. These results point to a significant role of photon attenuation in ²⁰¹Tl SPET imaging in the septum and posterior wall. It is concluded that ²⁰¹Tl SPET using a rest protocol identifies viable myocardium in the supply area of the LAD and in the lateral wall with high accuracy compared to ¹⁸FDG positron emission tomography while disordance in the posterior territory may be governed by photon attenuation in the SPET study rather than by a pathophysiological difference. Correspondence to: C. Aftehoefer     

A comparison of planar and tomographic thallium scintigraphy in patients with coronary artery disease

Planar and tomographic scans from 57 patient are compared and related to coronary arteriographic results. Tomography identified inferior and septal defects not seen on planar imaging. Planar imaging better identified apical defects. Lesions of the left circumflex were poorly defined by both techniques.     

A comparison of99mTc-MIBI myocardial SPET with electron beam computed tomography in the assessment of coronary artery disease

We compared technetium-99m methoxyisobutylisonitrile (MIBI) myocardial perfusion single-photon emission tomography (SPET) (MPS) and electron beam computed tomography (EBCT) in order to assess their respective value in the detection of coronary artery disease (CAD).^99mTc-MIBI SPET (stress-resting) and EBCT studies were performed in 51 patients with suspected CAD who underwent coronary angiography (CAG). CAG showed that of the 51 patients, 36 had coronary stenosis 50% while 15 had normal results. A moderate positive rank correlation was found between coronary calcification detected by EBCT and MPS score (r _s=0.5283,P<0.01). The concordance between EBCT and MPS for the evaluation of CAD was 72.5% (37/51). The sensitivity of EBCT in detecting CAD in 51 patients was comparable to that of MPS (81% vs 94%, NS). However, the accuracy of EBCT was lower than that of MPS (78% vs 94%,P<0.025). As regards the detection of individual coronary artery disease, there was no significant difference in sensitivity between EBCT and MPS (65% vs 75%, NS); however, the specificity and accuracy of EBCT were lower than those of MPS (specificity: 77% vs 95%,P<0.005; accuracy 71% vs 85%,P<0.005). The sensitivity, specificity and accuracy of MPS in detecting single-vessel disease were higher than those of EBCT (sensitivity: 86% vs 42%,P<0.025; specificity: 96% vs 70%,P<0.025; accuracy: 93% vs 61%,P<0.005). However, no significant differences in the sensitivity, specificity and accuracy of MPS and EBCT were found in respect of multivessel disease. In conclusion:^99mTc-MIBI myocardial perfusion SPET and EBCT provide different information in the assessment of CAD. The sensitivity of EBCT for the detection of CAD is comparable with that of MPS; however, the specificity and accuracy of EBCT are lower than those of MPS. More reliable results will be obtained if both myocardial perfusion SPET and EBCT are performed.     

动态容积320排冠状动脉CT血管成像诊断冠状动脉疾病的意义

目的：研究320排动态容积冠状动脉CT成像（CCTA）诊断冠状动脉疾病（CAD）的可行性。方法：5961例临床诊断CAD的患者进行CCTA检查,其中186例接受常规X线冠状动脉造影术（CAG）,对照分析其检查结果。1490例接受CCTA检查的健康查体者作为对照。结果：成像质量均在I～III级,无呼吸伪影图像。在186例CAD患者中,CCTA诊断冠状动脉狭窄（狭窄度≥50％）的敏感性为96．72％,特异性98．95％,阳性预测值95．16％,阴性预测值99．30％,准确度98．56％。结论：320排动态容积CT冠状动脉成像图像清晰,对诊断CAD具有重要的临床价值。     

128-Detector-Row Computed Tomography coronary angiography assessing differences in morphology and distribution of atherosclerotic plaques between patients with and without pre-test probability of significant coronary artery disease

Objectives

To evaluate and compare morphology, distribution and orientation of atherosclerotic plaques at the coronary arteries between patients with low and intermediate pre-test probability of significant coronary artery disease (CAD) by non-invasive coronary angiography using 128-Multi Detector Computed Tomography (MDCT).

Materials and methods

The study included 120 patients divided into two groups according to their clinical pre-test probability of having significant CAD: 38 patients (group A) with intermediate pre-test probability and 82 patients (group B) with low pre-test probability of significant CAD. Atherosclerotic plaques were characterized according to their morphology, distribution and orientation.

Results

A total of 482 plaques were analyzed. In group A, we found statistically significant higher percentages of RCA plaques (p = 0.0005), of concentric (p < 0.0001) and non-branching (p = 0.013) plaques, of myocardial plaques (p = 0.029), of plaques in distal RCA (p = 0.0009) and distal LAD (p = 0.001). In group B, we found statistically significant higher percentages of LAD plaques (p < 0.0001), of eccentric (p < 0.0001) and branching (p = 0.013) plaques, of lateral plaques (p = 0.012), of Medina 1.0.0 (p = 0.0069), 0.1.0 (p = 0.022) and 1.1.1 (p = 0.0068) branching plaques, and of plaques in proximal LAD (p = 0.02).

Conclusion

128-MDCT coronary angiography can provide important information on morphology and distribution of atherosclerotic plaques and may in the future play a potential role in patient management.     

阿托伐他汀对冠心病患者颈动脉内-中膜厚度的影响

目的：应用高频超声观察冠心病（cAD）患者，经阿托伐他汀治疗后对颈动脉内-中膜（IMT）的改善作用。方法：经冠脉造影（cAG）确诊为CAD并伴有颈动脉粥样硬化患者59例，利用高频超声血管技术检测阿托伐他汀对CAD患者治疗前后颈动脉最厚处和最薄处IMT。结果：阿托伐他汀组治疗2年后，冠心病患者颈动脉IMT最厚处和最薄处与治疗前相比均无显著性改变（P〉0．05）；常规治疗组治疗2年后，颈动脉IMT最厚处与治疗前相比无显著性改变（P〉0．05），IMT最薄处显著增厚（P〈0．05）。结论：阿托伐他汀具有稳定斑块、延缓粥样硬化斑块进展的作用。     

Diagnostic value of left ventricular function after adenosine triphosphate loading and at rest in the detection of multi-vessel coronary artery disease using myocardial perfusion imaging

Background  Although transient left ventricular (LV) dilation is a well-known marker for extensive coronary artery disease (CAD), few studies performed quantitative analysis of LV function of post adenosine triphosphate (ATP) stress and at rest to detect extensive CAD. Methods  One hundred nineteen patients with suspected CAD underwent post-stress and resting gated single-photon emission computed tomography (SPECT). Myocardial perfusion was assessed with a 20-segment model, and the changes in LV volume and function with ATP were analyzed. In addition, the stress-induced volume ratio (SIVR), defined as stress-to-rest ratios (end-systolic volume × 5 + end-diastolic volume), was calculated. All the patients underwent coronary angiography within 3 months of gated SPECT. Results  In the 62 patients with multi-vessel CAD, the summed stress score (SSS) (16.6 ± 8.7 vs 11.5 ± 9.1; P < .002), summed difference score (SDS) (9.6 ± 5.8 vs 3.9 ± 4.2; P < .0001), the post-stress increase in end-diastolic volume (EDV) (7.7 ± 7.9 vs 2.2 ± 5.3 mL; P < .0001), the post-stress increase in end-systolic volume (ESV) (9.4 ± 6.0 vs 2.7 ± 4.0 mL; P < .0001), and the (SIVR) (1.21 ± 0.14 vs 1.06 ± 0.10; P < .0001) were greater than in the 57 patients with insignificant or single-vessel CAD, whereas the post-stress increase in ejection fraction (EF) was less (−6.0 ± 4.9 vs −2.0 ± 4.4%; P < .0001). In the detection of multi-vessel CAD, an SSS of ≥14 and an SDS of ≥9 showed sensitivities of 57% and 52%, respectively, and specificities of 63% and 88%, respectively, while increase in EDV of ≥6 mL, increase in ESV of ≥6 mL, decrease in EF of ≥5% after stress, and SIVR of ≥1.13 demonstrated sensitivities of 60%, 81%, 60%, and 74% and specificities of 74%, 77%, 77%, and 79%, respectively. The multivariate discriminant analysis revealed that the combination of post-stress increase in ESV and the SDS best identified multi-vessel CAD, with 81% sensitivity and 77% specificity (χ² = 63.6), whereas the SDS alone showed 52% sensitivity and 88% specificity (χ² = 22.4). Conclusions  The addition of “post-ATP stress” and “at rest” LV functional analysis using gated SPECT to conventional perfusion analysis helps to better identify patients with multi-vessel CAD.     

64排螺旋CT冠脉成像在冠心病诊断中的应用

目的 评价64排螺旋CT冠状动脉(冠脉)成像(CTA)在冠心病诊断中的应用价值.方法 以选择性冠脉造影(SCA)结果为金标准,采用64排螺旋CT对68例疑诊冠心病患者的冠脉主干及主要分支272节段进行重建和分析,评价其诊断冠心病的灵敏度和特异度.结果 CTA能够清晰显示冠脉主干及其分支狭窄、钙化、开口起源异常及桥血管病变,CTA发现钙化病变52节段,SCA仅发现钙化病变35节段.CTA诊断冠脉病变的灵敏度96.33%,特异度98.16%,阳性预测值97.22%,阴性预测值97.56%.其中对左主干、左前降支病变及＞75%的病变灵敏度最高,分别达到100%和94.4%.结论 CTA对冠脉狭窄病变、桥血管、开口畸形、支架管腔均显影良好,对冠心病诊断有较高的准确性,对钙化病变诊断率优于冠脉造影,可以作为冠心病高危人群无创性筛选检查及冠脉支架术后随访手段.     

The association of coronary lumen volume to left ventricle mass ratio with myocardial blood flow and fractional flow reserve

BackgroundA diminished coronary lumen volume to left ventricle mass ratio (V/M) derived from coronary computed tomography angiography (CCTA) has been proposed as factor contributing to impaired myocardial blood flow (MBF) even in the absence of obstructive disease on invasive coronary angiography (ICA).MethodsPatients underwent CCTA, and positron emission tomography (PET) prior to ICA. Matched global V/M, global, and vessel specific hyperaemic MBF (hMBF), coronary flow reserve (CFR), and, FFR were available for 431 vessels in 152 patients. The median V/M (20.71 mm³/g) was used to divide the population into patients with either a low V/M or a high V/M.ResultsOverall, a higher percentage of vessels with an abnormal hMBF and FFR (34% vs. 19%, p = 0.009 and 20% vs. 9%, p = 0.004), as well as a lower FFR (0.93 [interquartile range: 0.85–0.97] vs. 0.95 [0.89–0.98], p = 0.016) values were observed in the low V/M group. V/M was weakly associated with vessel specific hMBF (R = 0.148, p = 0.027), and FFR (R = 0.156, p < 0.001). Among vessels with non-obstructive CAD on ICA (361 vessels), no association between V/M and vessel specific hMBF nor CFR was noted. However, in the absence of obstructive CAD, V/M was associated with (R = 0.081, p = 0.027), and independently predictive for FFR (p = 0.047).ConclusionOverall, an abnormal vessel specific hMBF and FFR were more prevalent in patients with a low V/M compared to those with a high V/M. Furthermore, V/M was weakly associated with vessel specific hMBF and FFR. In the absence of obstructive CAD on ICA, V/M was weakly associated with notwithstanding independently predictive for FFR.     

Assessment of myocardial perfusion and viability with technetium-99m methoxyisobutylisonitrile and thallium-201 rest redistribution in chronic coronary artery disease

We compare thallium-201 rest redistribution and fluorine-18 fluorodeoxyglucose ([¹⁸F]FDG) for the assessment of myocardial viability within technetium-99m methoxyisobutylisonitrile (MIBI) perfusion defects in 27 patients with chronic stable coronary artery disease. The following studies were performed: (1) stress^99mTc-MIBI, (2) rest^99mTc-MIBI, (3)²⁰¹T1 rest-redistribution single-photon emission tomography, (4) [¹⁸F]FDG positron emission tomography. The left ventricle was devided into 11 segments on matched tomographic images. The segment with the highest activity at stress was taken as the reference (activity=100%). Perfusion defects at^99mTc-MIBI rest were classified as severe (activity<50%), moderate (activity 50%–60%) or mild (activity 60%–85%). Uptakes of [¹⁸F]FDG and rest-redistributed²⁰¹Tl were recognized as significant if they exceeded 50% of that in the reference segment. Among the 33 segments with severe^99mTc-MIBI rest perfusion defects, 21 had significant [¹⁸F]FDG and 10 significant rest-redistributed²⁰¹Tl uptake. As regards the 37 segments with moderate defects, [¹⁸F]FDG was present in 29 and²⁰¹Tl in 31, while of the 134 segments with mild defects, 128 showed [¹⁸F]FDG uptake, and 131,²⁰¹Tl uptake. In conclusion, there is an inverse relationship between the severity of^99mTc-MIBI perfusion defects and the uptake of rest-redistributed²⁰¹Tl and [¹⁸F]FDG. Both tracers are adequate markers of viability in mild and moderate defects; in severe defects²⁰¹Tl might underestimate the presence of viability as assessed by [¹⁸F]FDG.     

Computational fluid dynamics in coronary artery disease

Computational fluid dynamics (CFD) is a widely used method in mechanical engineering to solve complex problems by analysing fluid flow, heat transfer, and associated phenomena by using computer simulations. In recent years, CFD has been increasingly used in biomedical research of coronary artery disease because of its high performance hardware and software. CFD techniques have been applied to study cardiovascular haemodynamics through simulation tools to predict the behaviour of circulatory blood flow in the human body. CFD simulation based on 3D luminal reconstructions can be used to analyse the local flow fields and flow profiling due to changes of coronary artery geometry, thus, identifying risk factors for development and progression of coronary artery disease. This review aims to provide an overview of the CFD applications in coronary artery disease, including biomechanics of atherosclerotic plaques, plaque progression and rupture; regional haemodynamics relative to plaque location and composition. A critical appraisal is given to a more recently developed application, fractional flow reserve based on CFD computation with regard to its diagnostic accuracy in the detection of haemodynamically significant coronary artery disease.