Neoatherosclerosis: overview of histopathologic findings and implications for intravascular imaging assessment.

Despite the reduction in late thrombotic events with newer-generation drug-eluting stents (DES), late stent failure remains a concern following stent placement. In-stent neoatherosclerosis has emerged as an important contributing factor to late vascular complications including very late stent thrombosis and late in-stent restenosis. Histologically, neoatherosclerosis is characterized by accumulation of lipid-laden foamy macrophages within the neointima with or without necrotic core formation and/or calcification. The development of neoatherosclerosis may occur in months to years following stent placement, whereas atherosclerosis in native coronary arteries develops over decades. Pathologic and clinical imaging studies have demonstrated that neoatherosclerosis occurs more frequently and at an earlier time point in DES when compared with bare metal stents, and increases with time in both types of implant. Early development of neoatherosclerosis has been identified not only in first-generation DES but also in second-generation DES. The mechanisms underlying the rapid development of neoatherosclerosis remain unknown; however, either absence or abnormal endothelial functional integrity following stent implantation may contribute to this process. In-stent plaque rupture likely accounts for most thrombotic events associated with neoatherosclerosis, while it may also be a substrate of in-stent restenosis as thrombosis may occur either symptomatically or asymptomatically. Intravascular optical coherence tomography is capable of detecting neoatherosclerosis; however, the shortcomings of this modality must be recognized. Future studies should assess the impact of iterations in stent technology and risk factor modification on disease progression. Similarly, refinements in imaging techniques are also warranted that will permit more reliable detection of neoatherosclerosis.

Optical coherence tomography assessment of the spatial distribution of culprit ruptured plaques and thin-cap fibroatheromas in acute coronary syndrome.

AIMS: Plaque rupture and subsequent thrombosis is known to be the most important pathology leading to acute coronary syndrome (ACS). We investigated by optical coherence tomography (OCT) whether in ACS there is an association of the location of the culprit plaque in the coronary tree with plaque rupture and/or thin cap fibroatheroma (TCFA). METHODS AND RESULTS: We included 74 patients presenting with ACS that underwent OCT study of the culprit lesion. The distance of the culprit lesion from the ostium was measured angiographically, and the presence of rupture and/or TCFA was assessed by OCT. Sixty-seven patients were analysed. Forty-five ruptured plaques were identified by OCT (67.1%). The distance from the ostium was lower for culprit ruptured plaques versus culprit non-ruptured plaques (p<0.01), particularly in the left anterior descending (LAD) and the left circumflex (LCx) arteries. The majority of culprit ruptured plaques (68.9%) was located in the proximal 30 mm of the coronary arteries. A distance from the ostium of ≤30.54 mm predicted plaque rupture with 71.1% sensitivity and 68.2% specificity. Culprit lesions in the proximal 30 mm are associated with rupture (p<0.05), TCFA (p<0.05), and lower minimal cap thickness (p<0.05). CONCLUSIONS: Culprit ruptured plaques in ACS seem to be predominately located in the proximal segments of the coronary arteries.

Discordance of the pediatric surgeon's intraoperative assessment of pediatric appendicitis with the pathologists report.

BACKGROUND/PURPOSE: The nature and duration of postoperative treatment in children with appendicitis is largely defined by the surgeon's intraoperative assessment of the degree of disease. Therefore, misclassification of patients could result in either inadequate or excessive duration of treatment. MATERIALS/METHODS: During the execution of an institutional review board-approved multicenter, randomized, prospective, single-blinded trial of laparoscopic versus open appendectomy in children, we tracked the attending pediatric surgeon's determination of the degree of appendicitis and compared it to the pathologists report. Postoperative care was determined, per protocol, by the surgeon's intraoperative classification. "Interval" appendectomies were excluded from the analysis. Statistical significance was analyzed using chi(2) analyses. RESULTS: A total of 133 patients were randomized into the open group, whereas 122 randomized to laparoscopy during the first 2 years of the study. The attending pediatric surgeons and pathologists were concordant in the determination of acute appendicitis in 90% of open patients and 93% of laparoscopic patients (P = not significant). When children were classified by the attending surgeon as having complicated appendicitis (gangrenous or ruptured), the concordance rate dropped to 38% and 52%, respectively (P = not significant). When open and laparoscopic patients were combined, the length of postoperative stay (LOS) of concordantly classified acute appendicitis patients was 35 +/- 16 hours. Concordantly classified complicated appendicitis LOS was 118 +/- 61 hours, and discordantly classified complicated appendicitis (pathology = acute) LOS was 85 +/- 41 hours (P = .01). Wound infection rates in the concordant and discordant "complicated" appendicitis groups were 23% and 7%, respectively (P = .05). When the surgeons are grouped as "junior"(n = 2) and "senior" (n = 3), there is a trend toward greater concordance in the latter group (P = .08). CONCLUSIONS: In the 2 institutions studied, the 5 pediatric surgeon's intraoperative classification of appendicitis correlated with the pathologist's reading in a high percentage of those patients labeled "acute" but in only approximately one half of those defined as "complicated." These phenomena are independent of the operative approach but may correlate with surgeon experience. Interventions to improve the timeliness of pathologic diagnosis may improve the accuracy and efficiency of care of pediatric appendicitis.