PLATELET DEPOSITION AFTER CAROTID ENDARTERECTOMY DECREASES WITH TIME.

1987 ◽  
Author(s):  
A C Meek ◽  
P Jarvis ◽  
C M Backhouse ◽  
CN McCollum ◽  
RM Greenhalgh
Keyword(s):  
Carotid Endarterectomy ◽  
Intimal Hyperplasia ◽  
Gamma Camera ◽  
Contralateral Side ◽  
Uptake Ratio ◽  
Platelet Deposition ◽  
Platelet Accumulation

Platelets are deposited on the exposed media following carotid endarterectomy and will continue to accumulate until neointima covers this thrombogenic surface. Radiolabelled platelet uptake was measured to assess the time to intimal repair.Autologous llllndium labelled platelets were infused 2 days and 2 months postoperatively in 10 patients undergoing unilateral carotid endarterectomy. Platelet accumulation was measured daily by gamma camera images counting radioactivity over the operated artery and comparing it to the contralateral side as Carotid Uptake Ratio (CUR).Mean (±sem) counts per gamma camera cell over the operated side at 24 hours were 46.3± 4.3 compared to 38.6± 3.9 on the unoperated side (p<0.001). At 2 months this difference had disappeared with counts of 38.8± 3.2 and 39.1± 3.2 over the operated and reference arteries respectively. Early postoperative CUR at 1.22± 0.04 was significantly higher than 1.01± 0.06 at 2 months which equates to no radiolabelled platelet uptake (p< 0.01). Radioiabellea platelet uptake was visible on 8 of the 10 early scans, but this was seen in only 2 patients at 2 months, both of whom had a persistently high CUR indicating continued platelet accumulation at that time.Early postoperative platelet deposition decreases in the weeks following carotid endarterectomy presumably due to the development of a neointima. Those cases with persistently high platelet accumulation may have luminal thrombus which could lead intimal hyperplasia and restenosis.

PATCH ANGIOPLASTY INCREASES PLATELET DEPOSITION FOLLOWING CAROTID ENDARTERECTOMY

1987 ◽  
Author(s):  
A C Meek ◽  
P Jarvis ◽  
R A Harper ◽  
C N McCollum
Keyword(s):  
Carotid Endarterectomy ◽  
Gamma Camera ◽  
Thrombus Formation ◽  
Uptake Ratio ◽  
Simple Closure ◽  
Patch Angioplasty ◽  
Significant Difference ◽  
Patch Closure ◽  
Platelet Accumulation ◽  
Dacron Patch

Patch angioplasty with vein or Dacron may be required to prevent narrowing when the arteriotomy is closed following carotid endarterectomy. We studied the effect of such patches on intraluminal thrombus formation by measuring radiolabelled platelet uptake in patients following simple closure and patch angioplasty.Following unilateral carotid endarterectomy in 33 patients, the arteriotomy was closed by direct suture in 23, Dacron patch in 6 and saphenous vein patch in 4. Autologous 111In-platelets were infused on the second postoperative day and platelet uptake over the carotid measured on daily gamma camera images for 3 days. Radioactivity over the operated and contralateral carotids were compared as the Carotid Uptake Ratio.Mean (±sem) counts per gamma camera cell at 24 hours in the operated carotid of 43.6±3.0 were consistently higher than the reference artery of 35.4±2.4 (p<0.001). The overall carotid uptake ratio was 1.21±0.04 with that of 1.41±0.07 in patch angioplasty significantly higher than 1.14±0.04 found following standard arteriotomy closure (p<0.01). All 10 patch angioplasties were easily visible as "hot spots" on gamma camera compared to only 11 out of 23 with simple closure but there was no significant difference between platelet uptake with vein or Dacron patches with ratios of 1.47±0.35 and 1.37±0.15 respectively (p>0.5).The greater local platelet accumulation with patch angioplasty may be due to turbulence from excessive widening of the vessel combined with the thrombogenic surface following endarterectomy. Until the significance of platelet accumulation is established platelet inhibitory therapy should be considered when patch closure is unavoidable.

PLATELET DEPOSITION AND PSEUDO-INTIMAL HYPERPLASIA IN PROSTHETIC VASCULAR GRAFTS

1987 ◽  
Author(s):  
R A Harper ◽  
I F Lane ◽  
C M Backhouse ◽  
C N McCollum ◽  
A C Meek
Keyword(s):  
Femoral Artery ◽  
Intimal Hyperplasia ◽  
Vascular Grafts ◽  
Graft Occlusion ◽  
Intimal Thickening ◽  
Arterial Grafts ◽  
Post Operative Period ◽  
Platelet Deposition ◽  
Platelet Accumulation ◽  
The Relationship

Platelet and fibrin accumulation in arterial grafts may cause pseudo-intimal hyperplasia and graft occlusion. The relationship between the rate of post-operative platelet accumulation and subsequent pseudo-intimal hyperplasia has been studied in prosthetic grafts implanted in greyhounds.The femoral artery in 30 greyhounds was replaced by a 6cm length of 6mm PTFE. Autologous 111In-platelet deposition over the graft was measured by probe and ratemeter for 7 days and radioactivity compared to the contralateral thigh. The daily increase in this ratio graft over reference was calculated as the Thrombogenicity Index (TI). Grafts were removed at 8 weeks and sectioned at 5, 30 and 55mm for measurement of pseudo-intimal thickening by grid microscopy.The animals subsequently developing occlusion or pseudo-intimal harrowing of greater than 50% of the lumen had a markedly greater TI of 0.22±0.027 compared to 0.03±0.019 in the 23 grafts maintaining wide patency (p<0.05). TI was highest in the 4 grafts which occluded at 0.3110.09 compared to 0.04±0.02 in the 26 that remained patent (p<0.01). There was a highly significant correlation (r=0.69) between post-operative TI and subsequent pseudo-intimal hyperplasia (p<0.001).Platelet deposition in the early post-operative period appears to promote the development of progressive pseudo-intimal thickening and ultimate occlusion

Neurosurgical applications of ocular pneumoplethysmography

1981 ◽  
Vol 54 (5) ◽  
pp. 588-595 ◽  
Author(s):  
William F. Bingham
Keyword(s):  
Standard Deviation ◽  
Carotid Artery ◽  
Intracranial Aneurysm ◽  
Carotid Endarterectomy ◽  
Contralateral Side ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Content Type ◽  
Final Adjustment ◽  
Fine Print

✓ Ocular pneumoplethysmography (OPG), a semiautomated form of suction ophthalmodynamometry, was used to evaluate and follow 15 patients who underwent carotid endarterectomy and two patients in whom gradual carotid artery occlusion was performed for inoperable intracranial aneurysm. Postoperative corrected ophthalmic arterial pressures (COAP's) on the operated side in the carotid endarterectomy patients averaged 12.5 mm Hg higher than before surgery, the standard deviation being 4.9 mm Hg for clinically stable patients. There was no significant change in COAP on the contralateral side. Several problems were encountered in closing down carotid clamps, the most potentially serious being a precipitous fall in COAP with the final adjustment. The current uses of OPG and similar techniques are reviewed, and potential neurosurgical applications are discussed.

Pravastatin and Clopidogrel Combined Inhibit Intimal Hyperplasia in a Rat Carotid Endarterectomy Model

2006 ◽  
Vol 40 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Shelly L. Bledsoe ◽  
John C. Barr ◽  
Ryan T. Fitzgerald ◽  
Aliza T. Brown ◽  
Fred H. Faas ◽  
...  
Keyword(s):  
Carotid Endarterectomy ◽  
Intimal Hyperplasia

Quantitation Of Platelet Lysis, Platelet Consumption On Oxygenator And Stabilization Of Platelet Membrane With Prostacyclin And Ibuprofen During Cardiopulmonary Bypass Surgery In Dogs

1981 ◽  
Author(s):  
M K Dewanjee ◽  
S R Vogel ◽  
K A Peterson ◽  
M P Kaye
Keyword(s):  
Cardiopulmonary Bypass ◽  
Surface Coating ◽  
Ionization Chamber ◽  
Gamma Camera ◽  
Bypass Surgery ◽  
Postoperative Bleeding ◽  
Membrane Oxygenator ◽  
Duration Of Action ◽  
Platelet Deposition ◽  
And Function

Prostacyclin (PGI2) and Ibuprofen (IP) may preserve platelet integrity and function during cardiopulmonary bypass (CPB). Platelet consumption on bubble and membrane oxygenator, platelet lysis, and platelet microembolism were studied in 7 control, 6 PGI2-, and 5 IP-treated dogs undergoing CPB. At 18 hours after I.V. administration of autologous In-Ill-labeled platelets (300 μCi), 7 heparinized dogs (300 u/kg), and 6 dogs treated with I.V. infusion of PGI2 (25 ng/kg/min) and heparin (100 u/kg), and 5 dogs with I.V. IP (12.5 mg/kg) 15 min prior to bypass procedure underwent CPB for 1 hour. In-111 in plasma obtained from platelet lysis was determined by centrifugation at 200,000 G of serial blood samples at 5-min intervals during CPB. Hemodilution was measured with I-125-labeled serum albumin (10 μCi). Platelet deposition on oxygenator was imaged with a gamma camera and quantitated with an ionization chamber. An insignificant amount of platelet (<0.2%) was found in the heat exchanger. In-111-labeled platelet level in blood of control dogs 20 min after CPB initiation decreased to 23 ± 5% of prebypass level, 38 ± 5% in PGI2 group, and 25 ± 5% in the IP group. Plasma In-111 increased to 34±7% in control, 15±5% in PGI2 group, and 17±3% in IP group (p< 0.01). Platelet deposition on the oxygenator amounted to 20±5% of In-111 platelets in control, 11±3% of PGI2, and 13±4% in IP group (p< 0.01). These results indicate that both PGI2 and IP significantly reduce platelet consumption in oxygenator and platelet lysis during CPB. Thus PGI2 may reduce postoperative bleeding. Ibuprofen, although preserving platelet function, has a longer duration of action and, hence, systemic administration prior to CPB is not practical. Surface coating of extracorporeal surfaces with IP might be beneficial.

The Duration Of Thrombotic Activity In Maturing Prosthetic Vascular Grafts In Man

1981 ◽  
Author(s):  
M Goldman ◽  
D Simpson ◽  
R J Hawker ◽  
H Norcott ◽  
Z Drolc ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Prosthetic Graft ◽  
Early Postoperative Period ◽  
Graft Occlusion ◽  
Survival Times ◽  
Normal Platelet ◽  
Platelet Survival ◽  
Platelet Accumulation ◽  
Reduced Rate

Prosthetic graft occlusion is most frequent in the early postoperative period when the luminal surface is highly thrombogenic. It is generally believed that graft maturation ultimately results in a non-thrombogenic surface. The accumulation of 111-Indium labelled autologous platelets in Dacron aorto-femoral grafts has been measured one week following surgery and at intervals of 3 months to 1 year.Platelets from 9 patients were labelled with 111-In-oxine and reinjected. Isotope emissions over the graft and a reference site (aortic arch) were measured daily for 7 days and gamma camera images taken on alternate days. Graft thrombo-genicity was calculated as the daily rise in the ratio of emissions graft/reference.All grafts, regardless of age, accumulated platelets and were imaged by gamma camera. Mean thrombogenicity (± SEM) one week after surgery was 0.207 ± 0.037 compared with 0.08 ± 0.025 at follow-up (p <0.01). The platelet survival during the early study was reduced at 6.805 ± 0.61 days but had recovered to a near normal value of 8.57 ± 0.78 days (p < 0.001) at follow up.Although at a reduced rate, platelet accumulation still occurs on Dacron grafts 1 year following surgery despite the presence of normal platelet survival times.

Sign in / Sign up

Export Citation Format

Share Document