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Background: Adequate microcirculation in different tissues maintains the physiological function and heals surgical wounds. In any surgical procedure, the commonly used instruments are cautery, tissue forceps, and clamps. The fact that their inappropriate use produces an adverse effect on microcirculation is often not realized. By this study, we could demonstrate live, the effect of these surgical traumas., Methods: The study was conducted on the inferiorly based fasciocutaneous flap with a fascial extension in patients with a distal leg defect. The extended fascial flap was mounted on a glass slide and observed for live microcirculation under x160 magnification. Three methods were used: (a) cautery in low power, (b) microcrushing forceps to crush the vessels, and (c) noncrushing clamps at the base of the fascial flap., Results: It was observed that the vessels are well protected within the deep fascia. Once the fascia was pierced the current damaged the vessel wall. As the wattage was increased, it caused charring of the tissue and multiple vessels ultimately leading to cessation of blood flow. Once the vessel wall was crushed by forceps, blood extravasated in a variable intensity depending upon the size of the vessel. Clamping led to gradual slowing of blood flow with microclot formation. In certain vessels, there was discontinuity in the blood column and ultimately the blood flow stopped., Conclusion: This study showed live demonstration of the effect of surgical traumas on microcirculation. It should guide the surgeons to select the use of appropriate instruments which will cause minimal damage to vascularity and thereby lead to a better surgical outcome.

Objectives: To understand the logistics and supply management system of drugs at different levels within the district health care delivery system of Dharbanga in Bihar., Method: This was a cross-sectional study in 3 Primary Health Centres (PHCs), 3 Additional Primary Health Centres (APHCs) and 6 Subcentres (SCs) during September-December 2008. The study subjects were Civil Surgeon, Pharmacists, Medical Officers, ANMs. Data was collected using qualitative and quantitative techniques from different stakeholders., Result: The health centers were severely understaffed and drug stores are managed by unqualified/untrained pharmacists. Drug list available was not fully matching with the need/requirement of the population. The vital and essential drugs required for various health centers were of short supply or unavailable in medical stores. MOs were unaware of budget allocation/allotment for their centers. Demand estimation of the drug items were not done scientifically hence quantity of drugs supplied was not in consonance with community needs. The existing guidelines were not followed as a result drugs like Zinc, Misoprostol and Magsulf were not available at the PHCs or APHCs. The storage and transportation facilities of drugs were found to be poor. Community members were not satisfied with the availability of drugs., Conclusion: The logistic and supply system of drugs in Darbhanga district is very weak, hence the needs of the catering population related to medicines was not fully met.

Background: Cilostazol has proven efficacy in increasing walking distance in claudicants, but it has not been demonstrated to be more effective than placebo in secondary cardiovascular prevention. The direct effect of exercise on platelet function remains less well defined. We have investigated the effect of combination treatment with aspirin and cilostazol on platelet activity in claudicants subjected to repeated treadmill exercise., Methods: Nineteen claudicants completed a double-blind, randomised, controlled, cross-over trial. Each subject received a 2-week course of aspirin (75mg) and placebo and aspirin and cilostazol (100mg twice daily). Following each 2-week treatment period, patients participated in a standardised treadmill test (3.2kmh(-1), 10 degrees incline) walking to maximal claudication distance. The exercise was repeated thrice in total, and blood was sampled before and after exercise. Platelet activation was measured using free platelet counting aggregation, flow cytometry for surface markers of platelet activation and soluble P-selectin assay., Results: Compared to aspirin and placebo, combination treatment with aspirin and cilostazol was associated with reduced arachidonic-acid-induced platelet aggregation (p<0.01, Wilcoxon signed-rank test). Aspirin and placebo treatment were associated with elevated P-selectin expression, platelet-monocyte aggregation and reduced CD42b expression (p<0.05, Wilcoxon signed-rank test) post-exercise. No difference was seen in spontaneous platelet aggregation whilst soluble P-selectin was reduced post-exercise with combination treatment with aspirin and cilostazol (p<0.05, Wilcoxon signed-rank test)., Conclusions: Combination treatment with aspirin and cilostazol results in suppression of platelet activation and reduces the effect of exercise on platelets. The benefit seen may be a result of cilostazol enhancing the inhibitory effect of aspirin on the cyclo-oxygenase pathway.

Background: Meckel's diverticulum of the small bowel is the commonest congenital abnormality of the gastrointestinal system. It is a recognised cause of small bowel obstruction; however, the mechanism behind such obstruction is variable., Case Report: We present case report about an adult male who presented with small bowel obstruction, requiring a laparotomy. He was found to have a strangulated loop of small bowel with an encircling Meckel's diverticulum around the base of the mesentry. This was resected with a small bowel anastomosis.He made a good recovery and was discharged home., Conclusions: Our case illustrates a rarely seen complication of obstruction and strangulation caused by Meckel's diverticulum. Yet this is not frequent enough to justify routine excision and the debate as to whether to remove an incidental Meckel's shall continue.

Introduction: The management of concurrently occurring abdominal aortic aneurysm and another intra-abdominal pathology is controversial and represents a difficult management problem for the surgeon. Most surgeons are reluctant to perform a second non vascular procedure at the time of the aneurysm repair because of the risk of graft infection. Some evidence suggests that the one-stage elective surgical treatment in selected patients with concomitant abdominal aortic aneurysm and other pathologies; especially Gastro-Intestinal malignancies, is safe with superior cost effectiveness. However, there is a major dilemma in the management patients with large aneurysm which require an urgent repair and presented with concomitant pathologies that carry a high risk of sepsis. In this case report, we describe an unusual presentation of a large aneurysm with concomitant Acute Appendicitis where both needed an urgent surgical intervention. To our best knowledge, there has been no similar case report published in literature., Case Report: A 66 years old Caucasian male presented with a dual pathology of large abdominal aortic aneurysm and acute appendicitis. The diagnosis was confirmed by Computerized Tomography scan of his abdomen. He underwent a 2-stage operation; open Appendicectomy followed by open repair of his aneurysm to avoid the risk of graft infection. He had an uneventful recovery period with a full return to normal life., Conclusion: The incidence of patients with abdominal aortic aneurysm and coexistent intra-abdominal surgical pathology is increasing, and the surgical strategy for those patients remains controversial. There are not enough studies that looked directly into the management of large abdominal aortic aneurysm which require an urgent repair and presented with concomitant pathologies that carry a high risk of sepsis. In such situations, simultaneous operations should be avoided because of the risk of prosthetic graft infection and priority should be given to the symptomatic or most life threatening condition. The second pathology should be dealt with as soon as possible; preferably within the same admission. More studies are needed to look into this issue; however, this would be rather difficult because of the uncommon and complex nature of such presentations.

Objective: To evaluate the effectiveness of a lingual mucosal graft (LMG) urethroplasty for anterior urethral strictures and the donor site complications., Methods: A total of 30 patients underwent urethroplasty for anterior urethral strictures using dorsal on-lay of a LMG from March 2006 to December 2006. Most patients had balanitis xerotica obliterans as the etiology. The mean stricture length was 10.2 cm (range 3.7-16.5). Postoperatively, all patients underwent pericatheter urethrography at 3 weeks, followed by retrograde urethrography with micturating cystourethrography, and uroflowmetry at 3 and 6 months. Repeat uroflowmetry was done as, and when, required., Results: The mean period of follow-up was 9 months (range 4-12). The overall success rate was 83.3%. The mean peak flow rate increased postoperatively from 4.36 mL/s to 35.5 mL/s at 3 months and 25.06 mL/s at 6 months of follow-up. One patient developed repeat stricture at the anastomotic site, and 4 patients developed recurrent meatal stenosis., Conclusions: The results of LMG urethroplasty were comparable to that of buccal mucosal graft urethroplasty. LMG is easy to harvest. Most importantly, the donor site complications were minimal without any functional or esthetic deficiency.

Objectives: To systematically review data to determine if endovenous laser ablation (EVLA), radio frequency ablation (RFA), and foam sclerotherapy (FS) have any advantages or disadvantages in comparison with conventional surgical ligation and stripping of great saphenous vein (GSV) varices., Evla Versus Surgery: The failure rate of GSV closure after EVLA was between 0% to 34%. In comparison the recurrence rate after high ligation and stripping was up to 28% in a meta analysis of 7 studies. The overall complication rate after EVLA is about 20%. This showed no difference from that after primary LSV surgery which is between 17% and 20%., Rfa Versus Surgery: There was no significant difference between RFA and surgery in terms of symptoms improvement. However, the pain score was better in the RFA groups. Moreover, there was significant difference in the sick leave taken after each treatment with the mean of 6.5 days and 4.7 days for RFA, and 15.6 days and 12.4 days for surgery. RFA versus EVLT: Immediate technical success was obtained in all (100%) of EVLA procedures and in (96%) of RFA cases. The overall complication rate was (20.8%) after EVLA and 7.6% after RFA., Foam Sclerotherapy: The recurrence rate after sclerotherapy reached 30.5 % after one year, and 51% after 10 years. However, the rates were better for foam than the liquid sclerosants. When compared to surgery, sclerotherapy had higher recurrence rate than that after surgery. The median time to return to normal activities was significantly reduced in the foam sclerotherapy group (2 days) compared to the surgical group (8 days)., Current & Future Development: When comparing the recurrence rate and overall complication rate and symptoms relief, surgery was not inferior to endovenous procedures. Reported follow up periods for the endovenous procedures were relatively short.

Background: P-selectin (PS) is a marker of platelet activation measured on the platelet surface as platelet PS (pPS) or in serum as soluble PS (sPS). Controversy remains over the exact relationship between sPS, pPS, and other markers such as spontaneous platelet aggregation (SPA)., Objective: To investigate correlations between pPS, sPS, and SPA in patients with peripheral arterial disease., Methods: SPA, pPS, and sPS levels were measured in venous blood sampled from patients following intermittent claudication (n = 18) or an acute stroke (n = 18)., Results: SPA and sPS correlated significantly in the claudicants (Pearson correlation coefficient, r = 0.661; P = .0020) and stroke patients (r = 0.514; P = .020). No significant correlation was identified between pPS and SPA, or sPS and pPS., Conclusions: The 2 methods of assessing PS are not comparable. Although pPS is accepted as a platelet activation marker, sPS may be a better indicator of aggregation represented by SPA.

Intra-arterial thrombolysis is an alternative treatment to surgery for acute limb ischemia. We report our own experiences by retrospectively assessing initial and long-term outcomes using this strategy. Patients (n = 48; 50 events) underwent thrombolysis according to our protocol (64.6% male, median age 68.5 years). Using thrombolysis as an initial treatment strategy, overall limb survival on index admission was 84%. Of this group who had successful limb salvage, 76% was attributable to thrombolysis alone, and 24% had limb salvage attributable to subsequent surgery after failed thrombolysis or anticoagulation. Significant complications occurred in 8% of cases, and no deaths were attributed to thrombolysis. Patients alive at 6 and 24 months after index admission who had limb salvage attributable to thrombolysis alone had limb survival rates of 89% and 82%, respectively. The majority of these patients had not required subsequent secondary procedures to maintain limb survival. Thrombolysis is an acceptable and less invasive treatment of acute limb ischemia, with many patients not needing subsequent surgery.

The most common symptom of lower extremity peripheral arterial disease (PAD) is intermittent claudication. The severity of PAD is closely related with the risk of myocardial infarction, ischaemic stroke, and death from vascular causes. Despite the higher prevalence of PAD, far less importance is given to its diagnosis and management. Patients with peripheral arterial disease should be offered secondary prevention strategies including aggressive risk factor modification and anti-platelet drug therapy. Cilostazol, a reversible, selective inhibitor of PDE III with antiplatelet, antithrombotic and vasodilatory effects, was approved by the FDA in 1999 for the treatment of Intermittent Claudication. It is believed that the collective pharmacology effect of cilostazol actually improves blood flow to the lower extremities. The efficacy of cilistazol has been demonstrated in eight Phase three clinical trials. Cilostazol is the first drug to consistently demonstrate clinical efficacy in many double-blind randomised control trials. It is indicated for the improvement of the maximal and pain-free walking distances in patients with IC, who do not have rest pain and who do not have evidence of peripheral tissue necrosis. In this review we highlight the role of Cilostazol in the management of peripheral arterial disease. The combined effect of aspirin with Cilostazol was recently patented.

The interfaces influence the phase stability of small particles. For embedded indium-tin alloy particles, the interface among the phases present within the particles and the matrix contribute significantly to the free energy and hence influences the phase stability at small sizes. Our results show that upon rapid cooling, we obtain a combination of larger two-phase alloy particles consisting of beta- and y-phases and very fine precipitates of In or Sn. Both beta- and gamma-phases possess an orientation relationship with Al. The in situ results suggest that the beta-rich phase gradually dissolved in the eutectic liquid before melting and the particles retain the facets much above the melting temperature of the alloy particle. We have tried to explain the formation and stability of these phases in terms of favorable nucleation kinetics.

Hypothenar Hammer syndrome' (HHS) describes the symptoms and signs produced by thrombosis or aneurysm of the ulnar artery as a consequence of repeated blunt trauma to the hypothenar eminence. We describe a case report of a man presenting with symptoms of ulnar artery thrombosis as result of blunt trauma secondary to his occupation and related patents. Radiological findings and management options are briefly discussed.

Objectives: Platelet monocyte aggregates (PMA) and monocyte chemoattractant protein-1 (MCP-1) play a significant role in atherosclerotic disease but the effect of aspirin and their role in peripheral arterial disease (PAD) requires further investigation. We have compared p-selectin, PMA and MCP-1 in patients with PAD treated with aspirin (75 mgs daily), with age matched controls not treated with aspirin., Materials and Methods: Using flow cytometry and ELISA, P-selectin, PMA and MCP-1 were compared in 3 populations; healthy controls (n=12), intermittent claudication (n=19) and critical limb ischaemia (CLI), (n=10)., Results: P-selectin was significantly higher in CLI patients (3.48% positive) compared to the claudicants (1. 36% positive) and the controls (1.76% positive). PMA levels were significantly higher for CLI population (44.5% positive) compared to the claudicants (20.48% positive) and the controls (28.33% positive). MCP-1 levels expression was significantly higher for the CLI patients (175.4 pg/mL) compared to the claudicants (76.1 pg/mL) and the controls (117.0 pg/mL)., Conclusion: Despite aspirin treatment CLI patients have higher platelet activation and MCP-1 expression than controls and claudicants. With increasing severity of disease aspirin is unable to suppress markers of platelet activation and pro-atherosclerotic chemokine expression which may represent another form of aspirin resistance.

Conjunctivo dacrocysto rhinal fistula is an abnormal communication between the conjunctival sac and nose through the lacrimal sac. This is a rare and infrequent complication of acute dacrocystitis and only scanty literature is available. Its management requires two layered closure, one for nasal lining and the other for the conjunctiva. We report such a fistula and its management in a young girl.

Defects involving the distal leg and foot are frequently encountered following various aetiological factors. Paucity of local tissue causes surgeons to resort to the retrograde peninsular flap, the cross leg flap or the free flap. With specific knowledge of perforators, the fasciocutaneous flap from the calf area can be transferred to the defect in a single stage based on skeletonised distal perforators. The surgical anatomy, flap planning and procedure have been detailed. Nineteen patients were treated during the period 1995 to 2005. The perforators were identified preoperatively by audio Doppler. The flaps were marked and dissected proximal to the defect skeletonising the distal perforators under loupe magnification and transferred to the defect in a single stage. The donor site was skin grafted. Out of 19 cases, 16 flaps healed uneventfully, one flap necrosed completely and in two cases there was marginal necrosis. The cases were followed up for 2-10 years with an average of 6 years. With detailed knowledge of perforators one can safely reconstruct distal moderate-size defects of the lower limb in a single stage, thus having the benefits of free tissue transfer without resorting to microsurgery. This technique has proved to be an advancement in the reconstructive repertoire allowing flaps of non conventional dimensions to be perfused by skeletonised perforators.

A distally based tenosynovial sheath of peroneal tendons was used as a flap with skin graft to cover the exposed tendo Achilles. The flap has a reliable blood supply being perfused by a constant sizeable musculofascial perforator. Cadaveric dissection with methylene blue dye study has been conducted to prove the rationality and reliability of blood supply. The position of the perforator had been confirmed prior to surgery by a hand-held Doppler. The flap used to cover the exposed Achilles tendon in five cases yielded positive results. To our knowledge, a retrograde flap of this nature is unprecedented though an antegrade flap of similar composition has been described.

Extensive studies have been carried out to understand the vascular anatomy of fasciocutaneous flaps both in human cadavers and in experimental models. Seldom has angiographic study been undertaken in clinical cases. Before peroperative clinical angiography, microangiographic study was performed on rabbits to understand the vascular supply of the skin and deep fascia. Major vascular dominance could be seen in the deep fascia compared with the skin. Thereafter, peroperative angiography was carried out to visualize the vascular network of fasciocutaneous flaps. The study was conducted in 10 patients who required antegrade fasciocutaneous flap for exposed upper two thirds of the tibia. It showed longitudinally oriented rich vascular network in the flap. This study provided peroperative objective assessment of the nature of vascularity and an explanation for the viability of fasciocutaneous flaps of nonconventional dimensions. The procedure did not have any detrimental effect on the physiology of the flap.

This is a study of 97 patients who underwent 106 femoropopliteal bypass grafts (9 bilateral bypasses) for short-distance claudication and critical ischemia. Patients were divided into 2 groups. The first group (n=64) was followed up by use of duplex scans. The second group (n=42) was followed up in clinic without duplex surveillance. Twenty-three patients from the surveillance group developed stenoses of the grafts. Of these, 14 underwent successful angioplasty. A total of 43 grafts became blocked. Graft occlusion was significantly more common in the nonsurveillance group (n=29) as compared to the surveillance group (n=14) after both 1 and 3 years of observation (p=0.001). Patients with critical ischemia showed a higher rate of graft occlusion than the claudicants (p=0.0075). Sixteen patients in the nonsurveillance group underwent above/below-knee amputation compared to 1 in the surveillance group. There was no significant difference in the mortality rate in the 2 groups. Graft surveillance helped to improve patency of grafts by identifying the correctable lesions.

Introduction: the diagnosis of thoracic outlet syndrome (TOS) relies heavily on subjective rather than objective assessment criteria. Subsequently, published results after surgical decompression vary considerably. This study aimed to use a symptom-based patient-directed questionnaire to assess the outcome after decompression for TOS., Methods: sixty patients who underwent decompression procedures were identified from a prospectively maintained vascular database. Patient records were analysed for details regarding initial presentation, investigation, type of procedure used for decompression and management. Outcome questionnaires were sent to all identified patients to give a patient-based outcome measure., Results: eighty-four per cent of patients responded. In 90% of these patients there was an improvement in symptoms post-surgery with a median follow up of 43 months. The results were not influenced by the procedure or approach used., Conclusion: surgery remains an effective tool in the management of TOS. A simple patient-directed questionnaire as used in this study could assist in the standardisation of outcome assessment.

Cells in the blood circulating through a vascular graft can contribute to endothelialization of its flow surface. We hypothesized that granulocyte colony-stimulating factor (G-CSF) could enhance this process by increasing circulating bone marrow progenitor cells. Ten dogs received composite grafts that were shielded from any source of endothelialization other than the circulating blood. On the seventh postoperative day and for 7 days thereafter, five dogs were injected subcutaneously with 10 mg/kg/day of human G-CSF. The additional five dogs, used as controls, received no G-CSF. Grafts were retrieved at 4 weeks. All dogs recovered promptly postoperatively. White cell counts in G-CSF dogs increased by an average of 9.5-fold at the end of treatment, and had returned to normal before retrieval. All grafts remained patent. G-CSF grafts had significantly higher endothelialization than the controls (82.2 +/- 9.2% vs. 23.7 +/- 4.4%, p = 0.0004), with extensive flow surface neointima, covered with a single layer of endothelium verified by FVIII/vWF and CD34 staining. Control grafts had virtually no neointima and were covered with a thin layer of fibrin coagulum. Significantly more endothelial-lined microvessels were also found in the G-CSF grafts than in the controls. Dogs treated with G-CSF have increased endothelialization of synthetic vascular grafts due to increased circulating bone marrow progenitor cells.

This study was designed to develop a large-animal model to study and validate transluminally placed endovascular grafts and related techniques for treating abdominal aortic aneurysms with minimal trauma. In four dogs, a segment of infrarenal abdominal aorta was dissected and an endarterectomy was performed through an aortotomy to remove the entire intima of this controlled aortic segment. The opening was patched with chemically processed bovine pericardium, and an identical patch was applied after aortotomy of the opposite side of the aorta. Aortic diameter and flow were measured before and after the procedure. Angiograms were obtained just before retrieval. All dogs recovered quickly with no complications. Aortic diameter increased approximately 2.7-fold. Aneurysm size and shape remained stable until the end of the experiments at 4 or 8 weeks. Gross and histologic studies for 4- and 8-week specimens were similar. Factor VIII/von Willebrand factor staining showed complete reendothelialization of the endarterectomized wall, with a moderate degree of intimal hyperplasia. The patch material retained its acellular nature and its surface was covered with thrombus or fibrinous material mixed with blood cells and inflammatory cells. Thus, this model is feasible and suitable for endovascular graft healing studies.

The authors have shown accelerated endothelialization on polyethylene terephthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow cells have a subset of early progenitor cells that express the CD34 antigen on their surfaces. A recent in vitro study has shown that CD34(+) cells can differentiate into endothelial cells. The current study was designed to determine whether CD34(+) progenitor cells would enhance vascular graft healing in a canine model. The authors used composite grafts implanted in the dog's descending thoracic aorta (DTA) for 4 weeks. The 8-mm x 12-cm composite grafts had a 4-cm PET graft in the center and 4-cm standard ePTFE grafts at each end. The entire composite was coated with silicone rubber to make it impervious; thus, the PET segment was shielded from perigraft and pannus ingrowth. There were 5 study grafts and 5 control grafts. On the day before surgery, 120 mL bone marrow was aspirated, and CD34(+) cells were enriched using an immunomagnetic bead technique, yielding an average of 11.4 +/- 5. 3 x 10(6). During surgery, these cells were mixed with venous blood and seeded onto the PET segment of composite study grafts; the control grafts were treated with venous blood only. Hematoxylin and eosin, immunocytochemical, and AgNO(3 )staining demonstrated significant increases of surface endothelialization on the seeded grafts (92% +/- 3.4% vs 26.6% +/- 7.6%; P =.0001) with markedly increased microvessels in the neointima, graft wall, and external area compared with controls. In dogs, CD34(+) cell seeding enhances vascular graft endothelialization; this suggests practical therapeutic applications. (Blood. 2000;95:581-585)

Background: We evaluated human and canine internal thoracic arteries (ITAs) to determine whether the latter is valid for studies relevant to clinical use., Methods: We studied 19 human ITAs obtained from 1 female and 14 male victims of recent fatal accidents who had no evidence of cardiovascular disease (mean age = 39+/-19 years; range = 15 to 79 years), and ITAs of 21 randomly-selected mongrel dogs of both sexes, weighing 18-40 kg (average = 24.3+/-5.7 kg). Specimens were fixed in formalin at a controlled pressure of 120 mm Hg, before extensive assessment that included intimal thickening, condition of the internal elastic lamina, and number of medial elastic lamellae and vasa vasorum., Results: The canine morphology and histology were similar to the human ITAs, but there was no intimal hyperplasia, and the media and adventitia were thinner (ITAs of humans older than 40 years had significant increases in medial thickness, as well as in overall length). Morphologically and histologically, the left and right canine ITAs were almost completely the same., Conclusions: Canine ITAs are valid for bilateral comparative studies and are a useful tissue source and model for clinically-relevant experimental studies.

The objective was to study results of carotid endarterectomies performed between 1975 and 1991, comparing primary closure to Dacron patch closure. This was a retrospective study. Data from patient follow-up by physical examination, chart review, and Duplex study were used. Scan data were obtained in 92 of the primary cases, at a mean of 5 years postoperatively, and in 63 of the patch cases, at a mean of 4.1 years postoperatively. During this period, 269 endarterectomies were closed primarily and 101 were closed with a knitted Dacron patch. Twenty patients in the primary group and nine patients with patch closure were lost to follow-up, which extended for up to 12.5 years, with a mean of 4.7 +/- 3.6 years. No acute closures, infections or aneurysms developed in either group. Perioperative stroke incidence was 4.1 per cent for primary closure and 3.0 per cent for the patch group (P > 0.05). Late stenosis occurred in 17.3 per cent of the primary group and 11.1 per cent of the patch closure group (P > 0.05). Five-year survival was 76.2 per cent in the primary group, compared with 79.2 per cent for patch closure. Late stroke incidence was 2.8 per cent in the primary group and 3.3 per cent in the patch closure group. Results of smaller (< or = 3.5 mm) carotid arteries closed with knitted Dacron patches are equivalent to those of larger carotid arteries closed primarily.