Administration Basic Sciences Clinical Sciences Centers of Excellence
 
Vascular Surgery

 

  

1)      Mechanisms of carotid atherosclerotic plaque instability and cause of stroke

 

Carotid artery atherosclerotic plaque instability and rupture leads to stroke.  Carotid-related stroke is a cause of significant morbidity and mortality in the United States; one person sustains a stroke every forty seconds.   Stroke is the third leading cause of death in the United States, with an estimated societal cost of at least $55 billion.  No reliable ways of predicting a symptomatic carotid plaque exist; asymptomatic patients are either followed clinically until symptoms develop or treated when a high-grade stenosis is found.  Predicting which asymptomatic patients will progress to symptomatology is currently not possible and the decision to intervene is left to clinical judgment.  Carotid plaque stability is likely related to differential molecular determinants of carotid atherosclerotic disease. 

 

Increasing evidence indicates beneficial anti-inflammatory effects of omega-3 fatty acids (n-3 FA), which decrease morbidity and mortality from cardiovascular disease.  Data from our laboratory provide novel and strong evidence for increased n-3 FA in stable human carotid atherosclerotic plaques, but not in unstable plaques.  Based on our data, we propose that the relative content of serum n-3 FA and other pro-inflammatory FA are associated with the transition of a stable to an unstable carotid atherosclerotic plaque.

 

We sought to test the hypothesis that pro-inflammatory cytokines are related to carotid plaque instability and thus their modulation might be related to the prevention of stroke.  Patients with at least 50% internal carotid artery stenosis undergoing carotid endarterectomy were included in this study; plaque stability was determined on the basis of clinical criteria and confirmed histologically.  Intra-plaque protein were extracted and analyzed by ELISA.  Statistical testing was performed using the two-tailed unpaired t-test.

 

Carotid plaques were obtained from 53 patients; 33 were considered stable and 19 unstable. Unstable carotid atherosclerotic plaques had significantly higher levels of expression of the chemokine MCP-1 (19.8 ± 0.61 pg/ml vs. 17.3 ± 0.56 pg/ml; p=.0051) compared to stable plaques.  Intra-plaque levels of C-reactive protein (CRP) (20.7 ± 0.64 pg/ml vs. 18.3 ± 0.53 pg/ml; p=.0056) and tumor necrosis factor-alpha (TNF-alpha) (450.1 ± 6.23 pg/ml vs. 326 ± 12.7 pg/ml; p<.0001) were similarly elevated in unstable compared to stable plaques.  Conversely, the anti-inflammatory cytokine interleukin-10 (IL-10) was decreased in unstable plaques (27.4 ± 0.40 pg/ml vs. 30.3 ± 0.52 pg/ml; p=.0002).  Unstable carotid plaques exhibit a pro-inflammatory cytokine profile.  MCP-1, which aids in the chemotaxis of monocytes, is elevated in unstable carotid atherosclerotic plaques.  Small molecule inhibition of MCP-1 may help in vulnerable plaque stabilization.

 

 

2)      Trans-radial artery approach for the endovascular management of threatened/failed arteriovenous fistula

 

Endovascular management of threatened or thrombosed arteriovenous fistulae (AVF) is generally done via a percutaneous transvenous (TV) approach. Direct AVF puncture has its limitations, including the need for a second fistula puncture to address juxta-anastomotic stenoses, increased risk of arterial embolization and fluoroscopic time.  We hypothesized that a trans-radial artery (TRA) approach would be safe and offer the full visualization of the AVF through a retrograde brachial angiogram and the ability to treat anastomotic/juxta-anastomotic stenoses through a single access sheath.  All dysfunctional AVFs (radiocephalic, brachiocephalic, and basilic vein transposition) are being entered in a prospective database.  Inclusion criteria for the TRA approach were the presence of a juxta-anastomotic stenosis and a negative Allen's test.  Endovascular treatment of juxta-anastomotic stenoses of AVFs represents a formidable challenge. The TRA approach is safe and feasible.  We demonstrate that it may be an alternative to the TV approach, particularly for the management of juxta-anastomotic stenoses.  Future studies will address whether this should be adopted for the treatment of other AVF stenoses, establish long-term patency, and address whether there is reduced radiation exposure thru this single puncture technique.

  

1)    Comparison of Carotid Ultrasound Texture Image Analysis With Histologix Specimens

Tapash K. Palit, MD
Assistant Professor of Clinical Surgery
tpalit@lsuhsc.edu

Robert Batson, MD, FACS
Professor of Surgery
Chief, Section of Vascular Surgery
bobbatson@bellsouth.net

Larry Hollier, MD, FACS
Professor of Surgery
Chancellor, LSUHSC at New Orleans
lhholl@lsuhsc.edu

Claudie Sheahan, MD
Assistant Professor of Surgery
csheah@lsuhsc.edu

Malachi Sheahan III, MD
Assistant Professor of Surgery
msheah@lsuhsc.edu

Yvonne Soniat
Coordinator, Vascular Clinic
ysonia@lsuhsc.edu

Departments and Centers Feedback School Home Search