Elevation in plasma MMP-9 following carotid endarterectomy is associated with particulate cerebral embolisation
K J Molloy1, M M Thompson, E C Schwalbe
1Department of Surgery, University of Leicester, UK.
Insights
Plasma matrix metalloproteinase-9 (MMP-9) levels increase after carotid endarterectomy (CEA) only in patients experiencing embolisation. This rise in MMP-9, a marker of cerebral damage, is more significant with higher emboli counts during CEA.
Area of Science:
- Biochemistry
- Neurology
- Vascular Surgery
Background:
- Matrix metalloproteinase-9 (MMP-9) is implicated in vascular remodeling and inflammation.
- Carotid endarterectomy (CEA) is a procedure to prevent stroke in patients with carotid artery disease.
- The role of MMP-9 in the context of CEA and potential embolisation is not fully understood.
Purpose of the Study:
- To investigate changes in plasma MMP-9 levels before and after CEA.
- To correlate MMP-9 levels with the presence and extent of embolisation during CEA.
Main Methods:
- An observational study involving 75 patients undergoing CEA.
- Plasma samples collected pre-operatively and 48 hours post-operatively.
- MMP-9 concentrations measured using ELISA; embolisation detected via Transcranial Doppler (TCD).
Main Results:
- Post-operative MMP-9 levels were significantly higher in patients with emboli (14.9 ng/ml) compared to pre-operative levels (8.8 ng/ml; p=0.038).
- No significant change in MMP-9 was observed in patients without embolisation (7.7 ng/ml vs. 7.1 ng/ml; p=0.364).
- A marked increase in MMP-9 was noted in patients with >2 emboli (3.4 to 19.3 ng/ml; p=0.041) versus those with 1-2 emboli (10.1 to 12.8 ng/ml; p=0.340).
Conclusions:
- Elevated plasma MMP-9 after CEA is associated with intraoperative embolisation.
- The magnitude of MMP-9 increase correlates with the number of emboli detected.
- These findings suggest MMP-9 elevation is a response to cerebral microembolic damage during CEA.
Objectives:
To study plasma MMP-9 levels before and after carotid endarterectomy (CEA).
Design:
Observational study.
Methods:
Pre-operative (morning of surgery) and post-operative (48 h) plasma samples were obtained from 75 consecutive patients undergoing CEA. MMP-9 concentrations were quantified using ELISA. Transcranial Doppler monitoring was performed on each patient to detect particulate embolisation during the dissection phase of the CEA, until the application of carotid clamps.
Results:
The median post-operative plasma MMP-9 level of emboli-positive patients was significantly higher than their median pre-operative value (14.9 ng/ml vs. 8.8 ng/ml; p=0.038). However, no significant difference was seen in the plasma MMP-9 level of emboli-negative patients (7.7 ng/ml vs. 7.1 ng/ml; p=0.364). A greater rise was seen in the median plasma MMP-9 levels of those patients suffering >2 emboli (from 3.4 to 19.3 ng/ml; p=0.041) than those patients suffering 1 or 2 emboli (from 10.1 to 12.8 ng/ml; p=0.340).
Conclusions:
Plasma MMP-9 only rises after CEA in patients with evidence of embolisation. This increase is more pronounced in those with high numbers of emboli. These data suggest that the increase in MMP-9 is due to cerebral damage caused by embolisation.
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