Thrombosis and morphology of plaque rupture using optical coherence tomography.

BACKGROUND: Thrombosis following plaque rupture is the main cause of acute coronary syndrome, but not all plaque ruptures lead to thrombosis. There are limited in vivo data on the relationship between the morphology of ruptured plaque and thrombosis. METHODS: We used optical coherence tomography (OCT) to investigate the morphology of plaque rupture and its relation to coronary artery thrombosis in patients with coronary heart disease. Forty-two patients with coronary artery plaque rupture detected by OCT were divided into two groups (with or without thrombus) and the morphological characteristics of ruptured plaque, including fibrous cap thickness and broken cap site, were recorded. RESULTS: The fibrous cap of ruptured plaque with thrombus was significantly thinner compared to caps without thrombus ((57.00 ± 17.00) µm vs. (96.00 ± 48.00) µm; P = 0.0076). CONCLUSIONS: Plaque rupture associated with thrombosis occurs primarily in plaque covered by a thin fibrous cap. Thick fibrous caps are associated with greater stability of ruptured plaque.

[Ex vivo assessment of coronary lesions by optical coherence tomography and intravascular ultrasound in comparison with histology results].

OBJECTIVE: To explore the diagnostic accuracy of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in the detection of ex vivo coronary plaques with different compositions compared with histology results. METHODS: OCT and IVUS were performed in 15 autopsied heart specimens and the isolated coronary artery was assessed by routine histological processing thereafter. Coronary plaques were classified into 3 types (lipid-rich plaque, calcified plaque and fibrous plaque) according to standard criteria respectively. Sensitivity and specificity for detection of different types of plaque by OCT and IVUS were calculated according histology results. RESULTS: Seventy seven coronary plaques were analyzed. OCT demonstrated a sensitivity and specificity of 69% and 88% for lipid-rich plaque, 93% and 92% for calcified plaque, 88% and 98% for fibrous plaque. IVUS demonstrated a sensitivity and specificity of 61% and 92%, 98% and 97%, 68% and 90% respectively. The agreement between OCT and IVUS in assessment of coronary plaque was 0.831 (Kappa = 0.72, P < 0.01). CONCLUSIONS: Both OCT and IVUS correctly detected ex vivo coronary plaques and there was a good agreement in assessment of coronary plaques between OCT and IVUS. OCT is superior to IVUS in assessment of fibrous plaque and is similar as IVUS in assessment of calcified plaque.

Optical coherence tomography assessment of edge dissections after drug-eluting stent implantation in coronary artery.

BACKGROUND: Edge dissections after coronary stent implantation are associated with increased short-term risk of major adverse cardiovascular events. The incidence and outcome of edge dissections after coronary stent implantation were reportedly different using different imaging techniques. We used optical coherence tomography (OCT) to assess the incidence, morphological findings and related factors of edge dissections after drug-eluting stent (DES) implantation. METHODS: Totally 42 patients with 43 de novo lesions in 43 native arteries undergoing DES implantation with OCT imaging were enrolled in this study. RESULTS: Nine edge dissections were detected in 43 arteries after DES implantation. There were four morphological patterns of stent edge dissections indentified in this study: (1) superficial intimal tears (n = 3), (2) subintimal dissections (n = 4), (3) split of media (n = 1), (4) disruption of the fibrotic cap of plaque (n = 1). Stent edge expansion and stent expansion were both higher in the group with dissections than those in the group without dissections (1.682 ± 0.425 vs. 1.229 ± 0.285, P = 0.0290; 1.507 ± 0.445 vs. 1.174 ± 0.265, P = 0.0072). CONCLUSIONS: The incidence of stent edge dissections detected by OCT was 21%. Stent edge dissection is related with stent edge expansion and stent expansion.

[Changes of vasoactive substances in myocardium of chronic renal ischemia rats].

OBJECTIVE: To investigate the relationship between the vasoactive substances including endothelin-1 (ET-1), calcitonin gene-related peptide (CGRP), and nitric oxide (NO) in myocardium and the cardiac functions in chronic renal ischemia rats. METHODS: Male Wistar rats weighting 180-200 g were randomly divided into 2 groups: operation group (n=30) and sham operation group (n=10). A ligation of abdominal aorta between right and left renal artery was made by silk suture in operation group and the necrosis degree of aorta was about 50%. Aorta was not ligated in sham operation group. Sixteen weeks after operation, invasive measurement of blood pressure and cardiac function were performed, and content of ET-1, CGRP, and NO in myocardium were determined. RESULTS: Compared with sham operation group, blood pressure significantly increased in the operation group after ligation, along with decreased cardiac systolic and diastolic function, increased left ventricular mass index. After 16 weeks, compared with sham operation group, the content of ET-1 in cardiac tissue were significantly elevated in operation group [(361.0+/-118.7) vs. (503.4+/-139.6 ) pg/ml, P<0.01), along with significantly decreased CGRP content [(74.4+/-24.8) vs. (45.4+/-15.1) pg/ml, P<0.01). The content of ET-1 in cardiac tissue was negatively correlated with the maximum pressure rise rate of left ventricular r=-0.37, P<0.05). CONCLUSIONS: Chronic kidney ischemia caused by abdominal aorta ligation may result in the increase of ET-1 content in cardiac tissue and decrease of CGRP decreased. The content of ET-1 in cardiac tissue is also negatively correlated with left ventricular systolic function.