Quantification of coronary artery stenosis with high-resolution CT in comparison with histopathology in an ex vivo study

Quantitative and large-format histochemistry to characterize peripheral artery compositional gradients

The femoropopliteal artery (FPA) is a long, flexible vessel that travels down the anteromedial compartment of the thigh as the femoral artery and then behind the kneecap as the popliteal artery. This artery undergoes various degrees of flexion, extension, and torsion during normal walking movements. The FPA is also the most susceptible peripheral artery to atherosclerosis and is where peripheral artery disease manifests in 80% of cases. The connection between peripheral artery location, its mechanical flexion, and its physiological or pathological biochemistry has been investigated for decades; however, histochemical methods remain poorly leveraged in their ability to spatially correlate normal or abnormal extracellular matrix and cells with regions of mechanical flexion. This study generates new histological image processing pipelines to quantitate tissue composition across high-resolution FPA regions-of-interest or low-resolution whole-section cross-sections in relation to their anatomical locations and flexions during normal movement. Comparing healthy ovine femoral, popliteal, and cranial-tibial artery sections as a pilot, substantial arterial contortion was observed in the distal popliteal and cranial tibial regions of the FPA which correlated with increased vascular smooth muscle cells and decreased elastin content. These methods aim to aid in the quantitative characterization of the spatial distribution of extracellular matrix and cells in large heterogeneous tissue sections such as the FPA. RESEARCH HIGHLIGHTS: Large-format histology preserves artery architecture. Elastin and smooth muscle content is correlated with distance from heart and contortion during flexion. Cell and protein analyses are sensitive to sectioning plane and image magnification.

Effects of long-term statin-treatment on coronary atherosclerosis in patients with inflammatory joint diseases

Background

The effect of statins over time on coronary atherosclerosis in patients with inflammatory joint diseases (IJD) is unknown. Our aim was to evaluate the change in coronary plaque morphology and volume in long-term statin-treated patients with IJD.

Methods

Sixty-eight patients with IJD and carotid artery plaque(s) underwent coronary computed tomography angiography before and after a mean of 4.7 (range 4.0–6.0) years of statin treatment. The treatment target for low density lipoprotein cholesterol (LDL-c) was ≤1.8 mmol/L. Changes in plaque volume (calcified, mixed/soft and total) and coronary artery calcification (CAC) from baseline to follow-up were assessed using the 17-segment American Heart Association-model.

Results

Median (IQR) increase in CAC after statin treatment was 38 (5–236) Agatston units (p<0.001). Calcified and total plaque volume increased with 5.6 (0.0–49.1) and 2.9 (0.0–23.5) mm³, respectively (p<0.001 for both). The median (IQR) change in soft/mixed plaque volume was -10 (-7.1–0.0), p = <0.001. Patients who had obtained the LDL-c treatment target at follow-up, experienced reduced progression of both CAC and total plaque volume compared to patients with LDL-c >1.8mmol/L (21 [2–143] vs. 69 [16–423], p = 0.006 and 0.65 [-1.0–13.9] vs. 13.0 [0.0–60.8] mm³, p = 0.019, respectively).

Conclusions

A progression of total atherosclerotic plaque volume in statin-treated patients with IJD was observed. However, soft/mixed plaque volume was reduced, suggesting an alteration in plaque composition. Patients with recommended LDL-c levels at follow-up had reduced atherosclerotic progression compared to patients with LDL-c levels above the treatment target, suggesting a beneficial effect of treatment to guideline-recommended lipid targets in IJD patients.

Intermediate CD14++CD16+ monocyte predicts severe coronary stenosis and extensive plaque involvement in asymptomatic individuals

Circulating leukocyte subtypes and monocyte subsets are independent predictors of cardiovascular events. We hypothesized that an increased leukocyte subtype would predict severe coronary stenosis and extensive plaque involvement. We retrospectively analyzed clinical, laboratory, and coronary CT data in a total of 588 asymptomatic adults (69% men; mean age, 57 ± 9 years) undergoing a general health check-up. Intermediate CD14⁺⁺CD16⁺ monocyte count had the strongest association with mixed and calcified plaque scores, whereas the numbers of neutrophils and classical CD14⁺⁺CD16^- monocytes were significantly associated with non-calcified plaque score. Only high CD14⁺⁺CD16⁺ monocyte count (>12 cells/μL) significantly predicted extensive plaque involvement [odds ratio 3.16 (95% confidence interval 1.84-5.43), P < 0.001; quartile 4 vs. 1-3] and severe coronary stenosis [3.67 (1.84-7.33), P < 0.001; quartile 4 vs. 1-3] after adjustments for Framingham Risk Score (FRS), metabolic syndrome, and C-reactive protein. The CD14⁺⁺CD16⁺ monocyte count, when added to FRS, significantly reclassified 30.4 and 26.7% of the overall and 50.2 and 36.2% of the intermediate-risk population (FRS 6-20%) for predicting extensive plaque involvement and severe coronary stenosis, respectively. Thus, in asymptomatic individuals, intermediate CD14⁺⁺CD16⁺ monocyte could independently predict severe CAD and improve risk stratification.

Calcium Scoring and Cardiac Computed Tomography

Although recent advances in noninvasive imaging technologies have potentially improved diagnostic efficiency and clinical outcomes of patients with acute chest pain, controversy remains regarding much of the accumulated evidence. This article reviews the role of coronary computed tomography (CT) angiography in the assessment of coronary risk, and its usefulness in the emergency department in facilitating appropriate disposition decisions. Also discussed is coronary artery calcification incidentally found on CT scans when done for indications such as evaluation of pulmonary embolism or lung cancer. The evidence base and clinical applications for both techniques are described, together with cost-effectiveness and radiation exposure considerations.