Gregor D. Shanik

Histologic characteristics of carotid artery plaque

Carotid plaque characteristics associated with the production of symptoms were identified with quantification of carotid plaque constituents in high-grade stenotic asymptomatic (n = 8) and symptomatic (n = 44) plaques. Asymptomatic plaques contained significantly more fibrous/collagen material (88%) than symptomatic plaques (66%) (p less than 0.05). Hemorrhage constituted 2% and 1% of asymptomatic and symptomatic plaques, respectively. The predominant nonfibrous material was a pink amorphous material mixed with cholesterol, which composed 7% of asymptomatic and 27% of symptomatic plaques (p less than 0.05). No relationship was found between plaque composition and the number of ipsilateral ischemic neurologic events, nor was there evidence of a healing process. B-mode ultrasound scanning had a sensitivity of 94% in identifying plaque with greater than 80% fibrous content. We believe that plaque composition may be a useful discriminating factor in selecting asymptomatic patients for carotid endarterectomy.

Haemorrhagic carotid plaque does not contain haemorrhage.

The presence of haemorrhage in carotid bifurcation atheromatous plaques is widely believed to be associated with the production of ischaemic neurological events. This study set out to characterise plaque composition in symptomatic (SYM) and asymptomatic (ASYM) patients and to identify, if possible, the origin of intra-plaque haemorrhage. Fifty-nine plaques (50 SYM and 9 ASYM) were serially sectioned and examined for haemorrhage, haemosiderin, fibrin, cholesterol and collagen. Immunoperoxidase and electron microscopy studies were carried out on sections from five plaques in order to identify blood breakdown products. Intra-plaque haemorrhage was identified in 40 (68%) plaques and was similar in SYM and ASYM plaques. In only one did it constitute more than 15% of plaque content, and in the remainder it consisted of small collections of erythrocytes constituting greater than 1% of plaque content in only 21 (35%) plaques. The predominant non-fibrous component was a pink amorphous material mixed with cholesterol. Apart from traces of platelet breakdown products there was no evidence of haemorrhage in this pink material. Plaque roof rupture or ulceration was seen in 39 (66%) and in almost all cases overlay the amorphous/cholesterol material. Blood vessels were identified in 51 87%) plaques but were in close proximity to haemorrhage in only nine (15%).

The comparison of type of incision for transperitoneal abdominal aortic surgery based on postoperative respiratory complications and morbidity

Equal access to the abdominal aorta can be attained through midline and transverse abdominal incisions. The surgical literature suggests that transverse incisions cause less postoperative pain and morbidity. Fifty patients (10 females and 40 males, mean age 67 years) undergoing abdominal aortic surgery were randomised to a midline (n = 25) or transverse (n = 25) incision. All patients were evaluated preoperatively and postoperatively for seven days. Changes in pulmonary function (FVC and FEV1), time to open and close the incision, analgesia used (morphine mg/kg/h), clinical or X-ray evidence of chest infection, and the duration of ICU stay were recorded. In the transverse group there was a reduction in the incidence of chest complications (20% vs. 28%, p = ns) and these incisions took longer to open (13.9 +/- 4.6 vs. 9.9 +/- 5.1, p < 0.05), but overall there was no significant difference between any other parameter in the two groups. Our results show no statistically significant difference in morbidity or analgesia consumption following transverse or midline abdominal incisions and we conclude that the type of incision used can be left to the surgeons preference.

Asymptomatic carotid stenosis: A benign lesion?

Recent reports of the risk of asymptomatic carotid stenosis have been compromised by flawed patient selection or the performance of a large number of carotid endarterectomies during follow-up. We report the natural history of a randomly selected group of asymptomatic patients (n = 188; 114 males and 74 females) with documented carotid artery disease who were prospectively followed without intervention for up to 8 years. Risk factors included ischaemic heart disease in 17%, diabetes in 10%, hypertension in 46% and 88% were smokers. The degree of internal carotid stenosis was classified by duplex scanning and a total of 259 vessels had evidence of atherosclerosis. Study end-points included TIA, CVA and death. At mean follow-up of 4 years 3% of the 96 patients with internal carotid artery stenosis of less than 50% had died and 2% suffered a stroke. Six per cent of patients with a stenosis of 50-79% had died and 4% and 2% had suffered a CVA and TIA, respectively. In the 59 patients with greater than 80% stenosis 7% had suffered a TIA and an additional 7% a CVA, while 2% had died. None of the patients suffering a stroke had an antecedent TIA. Though the incidence of ischaemic events is significantly higher in patients with greater than 80% stenosis the incidence of unheralded stroke remains low. We therefore continue to recommend a conservative approach to the management of asymptomatic carotid stenosis.

Skin Closure and the Incidence of Groin Wound Infection: A Prospective Study

Groin wound infection is a dreaded complication of vascular surgery and may jeopardize an underlying graft. A variety of skin closures have been used and the object of this study was to prospectively determine the relationship between skin closure and wound infection. One hundred fourteen consecutive patients (70 men and 44 women) undergoing bypass surgery with a groin incision (n = 173) were randomly assigned to skin closure with subcuticular Maxon, interrupted nylon, continuous nylon, or clips following a standard two-layer closure of subcutaneous tissue. Fourteen (12%) patients had diabetes and 50 (44%) had digital ulceration and gangrene. Aortofemoral bypass was performed in 25% of the patients and infrainguinal bypass in the remaining 75%. Perioperative wound cultures were obtained before closure. Wounds were inspected and cultures repeated on postoperative days 3, 5, 7, 10, and 14. Infection was defined as a positive culture. Groin wound infection occurred in 3% of the population and graft infection in 0.6%. The type of suture did not influence the incidence of infection. This study failed to demonstrate a significant difference in the incidence of wound infection with the use of different suture materials. We conclude that suture material should be selected on the basis of surgeon preference and costs.

Upper limb embolus: a timely diagnosis.

In a ten year period, 36 patients were treated surgically for embolic occlusion of upper limb vessels. The sources of embolus were cardiac (58%), peripheral aneurysm (22%) and unknown (20%). Brachial embolectomy was performed in all cases. Six out of eight peripheral aneurysms were resected. A patency rate of 94% was achieved at five years. Hospital mortality and morbidity rates were 3% and 10%, respectively. One patient died of a myocardial infarct one week postoperatively. Three patients suffered ischemic contracture or amputation; all three presented after 36 hours. We conclude that upper limb emboli are usually easy to recognize and treat. Prompt surgery (< 24 hours) produces the most satisfactory results. Late presentation or delay in treatment can result in limb loss.

Infrainguinal polytetrafluoroethylene grafts: saved limbs or wasted effort? A report on ten years' experience.

Two-hundred and twenty-four infrainguinal polytetrafluoroethylene reconstructions were performed for critical ischemia over a 10 year period: 48 to the above-knee popliteal artery, 113 to the below-knee popliteal artery, and 63 to the tibial vessels. The cumulative patency rates were 84±6% and 63±9% for above-knee popliteal, 53±5% and 35±7% for below-knee popliteal, 45±6% and 30±9% for tibial vessels at one and five years respectively. Limb salvage rates were 81±6% and 73±9% (above-knee popliteal), 69±5% and 57±9% (below-knee popliteal), 64±7% and 32±10% (tibial vessels) at one and five years respectively. Graft occlusion did not result in limb loss in 32 cases. Preoperatively, 54% of the patients had limited mobility while 43% were regarded as severely restricted. At follow-up, 57% of the patients were considered to be independent, 26% had limited mobility, and 17% were still severely restricted. Polytetrafluoroethylene provides good short-term limb salvage and improved mobility in patients with critical ischemia and poor life expectancy. Its use is well worth the effort.

Pedal vasomotor tone following aortofemoral reconstructions: a randomized study of concomitant lumbar sympathectomy.

A prospective randomized trial was undertaken to evaluate effects of lumbar sympathectomy as an adjunct to reconstructive surgery of the lower limb. The objective of this study was to assess the early postoperative effect of these procedures on pedal vasomotor tone. A pedal arterial resistance index (PARI) at rest was derived from the ratio of the ankle-digit systolic pressure gradient and pedal blood flow measured plethysmographically. Studies were performed on 32 normal individuals and pre- and postoperatively in 29 patients undergoing aortic reconstruction, 12 of whom were randomly chosen to have lumbar sympathectomy. The mean postoperative PARI in 17 patients who had reconstructions alone was 42 ± 7 (S.E.M.) units which approximated the preoperative PARI (43 ± 9 units) and normal control values (45 ± 6 units). In contrast, 12 patients who had a concomitant lumbar sympathectomy had a significant reduction in the postoperative PARI (8 ± 1 units, P < 0.005). These initial results indicate that the addition of lumbar sympathectomy to an aortic reconstruction may enhance blood flow to the foot by significantly reducing outflow resistance.

Improved limb salvage and mobility following peroneal artery bypass

During the 10-year period August 1981 to 1991, 92 consecutive patients underwent revascularisation to the peroneal artery (40 to the upper third, 30 to the mid and 22 to the distal third). The male/female ratio was 1.6:1 and the mean age was 72 years. Thirteen patients had independent mobility preoperatively while 58 had limited mobility and the remaining 18 were bed/housebound. Following surgery the patients were prospectively evaluated and mean follow-up was 25 months. The 1 and 3 year patency rates were 67 and 59% respectively and cumulative limb salvage rates were 75 and 71%. Forty-four patients returned to independent mobility while 36 had limited mobility and 11 remained housebound. Reconstruction to the peroneal artery is a valuable adjuvant for limb salvage providing satisfactory cumulative patency and facilitating improved mobility.

Critical Ischemia Transfemoral Endoluminal Aortic Management: A Minimally Invasive Option in Aortic Intervention

Conventional aortic surgery carries a significant mortality and morbidity. Transfemoral endoluminal aortic management (TEAM) offers a minimally invasive alternative. This article reports seven cases of TEAM for aortoiliac disease and abdominal aortic aneurysms with a patency rate of 100% at 24 months. Our data suggests that primary stenting can achieve excellent physiologic results and restoration of blood flow in selected patients with aortoiliac disease. Long-term study and follow-up is essential to determine the place of TEAM in the field of vascular surgery.