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Aims: To understand wound healing after drug-eluting stents (DES) placement in humans, we studied the histology of in-stent restenosis (ISR) tissue obtained by atherectomy from bare metal stents (BMS) and DES in comparison with de novo atherosclerosis., Methods and Results: The tissue was retrieved from ISR in ten sirolimus-eluting stents (SES) and nine paclitaxel-eluting stents (PES), six BMS, and nine stenotic de novo atherosclerotic lesions and processed for histology and immunocytochemistry. Patients with ISR in PES showed a significantly higher incidence of unstable angina upon presentation for re-intervention (P = 0.046). De novo tissue tended to be more collagen rich, whereas ISR tissue tended to be more proteoglycan rich. In all groups, cell content consisted almost exclusively of smooth muscle cells. Histology showed that fibrinoid in ISR tissue was present only in DES (P = 0.004), as late as 2 years following DES placement, indicating a persistent incomplete healing response. The amount of fibrinoid, given as a percentage of total tissue in each atherectomy specimen, was greater in PES than in SES (17 vs. 5%, P = 0.026)., Conclusion: ISR in DES shows incomplete neointimal healing as late as 2 years after implantation. Patients with ISR in PES presented with more unstable angina and showed more pronounced signs of delayed healing than SES.

Objective: To describe the complications that occur within 30 days following the placement of a stent in the carotid artery in patients with considerable symptomatic carotid stenosis., Design: Retrospective., Method: Data were collected on 98 patients who received a carotid stent due to symptomatic carotid stenosis of > or = 70% of the lumen at the Erasmus MC, Rotterdam, the Netherlands, in the years 1999-2004. A filter, distal occlusion balloon or the Parodi anti-embolism system was used to prevent cerebral embolism. Outcome measures were complications within 30 days following intervention., Results: Four patients were excluded in the period between diagnosis and stenting. Major complications occurred in 3 patients: 1 died due to cerebral haemorrhage and 2 experienced cerebral infarction. Transient neurological complications occurred in 4 patients who recovered completely. Dissection of the renal artery occurred in 1 patient, which necessitated a stent. Vascular damage of the internal carotid artery was not observed in any patient. The 3 major adverse events and 3 of the 4 minor adverse events occurred in the first 47 patients treated. None of the last 47 patients treated developed major adverse events.

Purpose: To investigate the pressure gradient and degree of flow reduction associated with embolus protection filters for carotid stenting in an in vitro experiment., Methods: Three filter devices with a perforated membrane design and one wire mesh type filter were tested. At a pressure of 70 mmHg, the flow reduction and pressure gradient were measured in a 5-mm tube using blood-mimicking fluid., Results: The pressure gradient in the wire mesh filter was 1.65+/-0.49 mmHg (95% CI 1.32 to 1.86). The mean pressure gradient in the perforated membrane filters was 6.88+/-2.62 mmHg (95% CI 6.22 to 7.55, p<0.0001). There was also a significant correlation between pressure gradient and flow reduction (r=-0.77, p<0.01)., Conclusion: Embolic protection filters cause a pressure gradient and obstruct blood flow. This effect is marked in perforated membrane filters and almost absent in the wire mesh filter.