G. Patrick Clagett

The North American Symptomatic Carotid Endarterectomy Trial: Surgical Results in 1415 Patients

BACKGROUND AND PURPOSE This study reports the surgical results in those patients who underwent carotid endarterectomy in the North American Symptomatic Carotid Endarterectomy Trial (NASCET). METHODS The rates of perioperative stroke and death at 30 days and the final assessment of stroke severity at 90 days were calculated. Regression modeling was used to identify variables that increased or decreased perioperative risk. Nonoutcome surgical complications were summarized. The durability of carotid endarterectomy was examined. RESULTS In 1415 patients there were 92 perioperative outcome events, for an overall rate of 6.5%. At 30 days the results were as follows: death, 1.1%; disabling stroke, 1.8%; and nondisabling stroke, 3.7%. At 90 days, because of improvement in the neurological status of patients judged to have been disabled at 30 days, the results were as follows: death, 1.1%; disabling stroke, 0.9%; and nondisabling stroke, 4.5%. Thirty events occurred intraoperatively; 62 were delayed. Most strokes resulted from thromboembolism. Five baseline variables were predictive of increased surgical risk: hemispheric versus retinal transient ischemic attack as the qualifying event, left-sided procedure, contralateral carotid occlusion, ipsilateral ischemic lesion on CT scan, and irregular or ulcerated ipsilateral plaque. History of coronary artery disease with prior cardiac procedure was associated with reduced risk. The risk of perioperative wound complications was 9.3%, and that of cranial nerve injuries was 8.6%; most were of mild severity. At 8 years, the risk of disabling ipsilateral stroke was 5.7%, and that of any ipsilateral stroke was 17.1%. CONCLUSIONS The overall rate of perioperative stroke and death was 6.5%, but the rate of permanently disabling stroke and death was only 2.0%. Other surgical complications were rarely clinically important. Carotid endarterectomy is a durable procedure.

Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities: A Critical Review

Atherosclerosis is the most common cause of chronic arterial occlusive disease of the lower extremities. The arterial narrowing or obstruction that occurs as a result of the atherosclerotic process reduces blood flow to the lower limb during exercise or at rest. A spectrum of symptoms results, the severity of which depends on the extent of the involvement and the available collateral circulation. Thus, symptoms may range from intermittent claudication to pain at rest. Intermittent claudication denotes pain that develops in the affected limb with exercise and is relieved with rest. This pain usually occurs distal to the arterial narrowing or obstruction. Since the superficial femoral and popliteal arteries are the vessels most commonly affected by the atherosclerotic process, the pain of intermittent claudication is most often localized to the calf. The distal aorta and its bifurcation into the two iliac arteries are the next most frequent sites of involvement. Narrowing of these arteries may produce pain in the buttocks or the thighs as well as the legs. Epidemiological studies indicate that up to 5% of men and 2.5% of women 60 years of age or older have symptoms of intermittent claudication.1 2 The prevalence is at least threefold higher when sensitive noninvasive tests are used to make the diagnosis of arterial insufficiency in asymptomatic and symptomatic individuals.3 The symptoms of chronic arterial insufficiency of the lower extremities progress rather slowly over time. Thus, after 5 to 10 years, more than 70% of patients report either no change or improvement in their symptoms, while 20% to 30% have progressive symptoms and require intervention, and less than 10% need amputation.4 5 Despite the relatively benign prognosis for the affected limb, however, symptoms of intermittent claudication should be viewed as a sign of systemic atherosclerosis. This explains why, compared with …

Low-dose and high-dose acetylsalicylic acid for patients undergoing carotid endarterectomy: a randomised controlled trial *

BACKGROUND Endarterectomy benefits certain patients with carotid stenosis, but benefits are lessened by perioperative surgical risk. Acetylsalicylic acid lowers the risk of stroke in patients who have experienced transient ischaemic attack and stroke. We investigated appropriate doses and the role of acetylsalicylic acid in patients undergoing carotid endarterectomy. METHODS In a randomised, double-blind, controlled trial, 2849 patients scheduled for endarterectomy were randomly assigned 81 mg (n=709), 325 mg (n=708), 650 mg (n=715), or 1300 mg (n=717) acetylsalicylic acid daily, started before surgery and continued for 3 months. We recorded occurrences of stroke, myocardial infarction, and death. We compared patients on the two higher doses of acetylsalicylic acid with patients on the two lower doses. FINDINGS Surgery was cancelled in 45 patients, none were lost to follow-up by 30 days, and two were lost by 3 months. The combined rate of stroke, myocardial infarction, and death was lower in the low-dose groups than in the high-dose groups at 30 days (5.4 vs 7.0%, p=0.07) and at 3 months (6.2 vs 8.4%, p=0.03). In an efficacy analysis, which excluded patients taking 650 mg or more acetylsalicylic acid before randomisation, and patients randomised within 1 day of surgery, combined rates were 3.7% and 8.2%, respectively, at 30 days (p=0.002) and 4.2% and 10.0% at 3 months (p=0.0002). INTERPRETATION The risk of stroke, myocardial infarction, and death within 30 days and 3 months of endarterectomy is lower for patients taking 81 mg or 325 mg acetylsalicylic acid daily than for those taking 650 mg or 1300 mg.

Autogenous aortoiliac/femoral reconstruction from superficial femoral-popliteal veins: Feasibility and durability

PURPOSE Autogenous aortoiliac/femoral reconstruction with superficial femoral-popliteal veins (SFPVs) has been successfully used to treat prosthetic infection and failure, but outcome data are scant. In this prospective, observational study, we hypothesized that (1) replacement of the aortoiliac/femoral system with SFPVs could be performed with perioperative morbidity and mortality rates equal to those of conventional methods; (2) long-term patency rates would be excellent; (3) limb salvage rates would be correspondingly high; (4) aneurysmal degeneration would not occur, and (5) venous morbidity would be minimal. METHODS Since 1990, 41 patients have undergone complete or partial aortoiliac/femoral reconstruction with 63 SFPVs with a mean (+/-SD) follow-up time of 32 +/- 21 months. With the exception of two patients lost to follow-up, all have been observed at 6-month intervals with clinical examination and noninvasive tests. RESULTS There were no immediate operative deaths, but three patients (7.3%) died of multisystem organ failure after 1 month. Forty-nine percent of patients had significant perioperative complications including amputation (5%), compartment syndrome (12.3%), and pulmonary embolism (2.4%). Most patients (85%) had multilevel occlusive disease, and the mean SVS/ISCVS runoff score for the group was 4.9 +/- 2.6 (1 = normal, 10 = no runoff). Fifty-eight percent of all distal anastomoses were end-to-end, and in 68% of limbs the profunda femoris artery or superficial femoral artery was the sole runoff vessel. At 5 years, the cumulative secondary patency rate was 100%; primary patency rate, 83%; limb retention rate, 86%; and survival rate, 69%. Four patients had permanent limb edema controlled by compression stockings but none have had venous ulceration. There has been no aneurysmal dilation of SFPV grafts, and mean diameter shown by serial duplex imaging at 6 months (10.8 +/- 1.1 mm) was not significantly different from that at 60 months (7.8 +/- 1.1 mm). CONCLUSIONS Aortoiliac/femoral reconstruction with SFPVs is a successful and durable option for infection and other complex aortic problems.

Creation of a neo-aortoiliac system from lower extremity deep and superficial veins

OBJECTIVE This study evaluated the morbidity, mortality, and intermediate term follow-up of patients undergoing replacement of their aortoiliac-femoral systems with lower extremity deep and superficial veins. SUMMARY BACKGROUND DATA The most commonly used treatment for aortic prosthetic infection is ectopic bypass and removal of the prosthesis. The overall mortality rate with this approach is approximately 20%, with an amputation rate of 10% to 14%. Other limitations include thrombosis of the ectopic bypass leading to limb loss, reinfection of the ectopic bypass, and aortic stump blowout. Dissatisfaction with this approach has led the authors to develop the following. METHODS A neo-aortoiliac system (NAIS) was fashioned from lower extremity deep veins (DV), greater saphenous veins (GSV), or both in patients with infected aortobifemoral prosthesis (n = 17) and other complex aortic problems (n = 3). Removal of infected prosthetic material, harvest of vein, and creation of NAIS was performed as a single-staged procedure. RESULTS The in-hospital mortality and amputation rates were 10% each. The mean (+/- standard deviation [SD]) operative time was 6.5 +/- 1.8 hours and the blood transfusion requirement was 4 +/- 3 units. Four patients experienced postoperative gastrointestinal complications with peritonitis and sepsis; NAIS vein graft resisted infection and remained intact. The mean follow-up time was 22.5 +/- 16 months. NAISs constructed from GSVs were prone to the development of focal stenoses requiring intervention or diffuse neointimal hyperplasia leading to occlusion. In contrast, all NAISs from larger caliber DVs have remained widely patent. The failure rate of GSV NAISs was 64%, compared to 0% for DV NAISs (p = 0.006). Despite the high failure rate in patients with GSV NAISs, none has required amputation. In patients who had DVs harvested for NAIS reconstruction, limb edema and other signs of venous hypertension have been minimal. CONCLUSION NAIS reconstruction from lower extremity veins is a successful option in patients with extensive aortic prosthetic infection and other complex aortic problems.

Effectiveness of pulmonary artery catheters in aortic surgery: A randomized trial

PURPOSE To evaluate the routine use of pulmonary artery catheters (PAC) in patients who undergo aortic surgery. METHODS One hundred twenty patients were randomized to placement of PACs for perioperative monitoring and hemodynamic optimization (tune up) in the intensive care unit on the night before aortic operation, or to intravenous hydration in the ward and perioperative monitoring without PACs. Before randomization, all patients underwent routine adenosine thallium-201 scintigraphy. RESULTS To meet predetermined endpoints, 30 PAC patients (50%) received nitrates, inotropic agents, or both. PAC patients received more fluid in the preoperative period (p < 0.001) and in the first 24 hours after operation (p = 0.002) than control subjects. Eleven PAC patients (18%) and three control subjects (5%) had adverse intraoperative events (p = 0.02). There were 20 adverse postoperative events in 15 PAC patients (25%; nine cardiac, seven pulmonary, four acute tubular necrosis), which was not different compared with 11 postoperative events in 10 control subjects (17%; five cardiac, five pulmonary, one acute tubular necrosis). There were also no differences in duration of mechanical ventilation, intensive care unit stay, or hospital stay between groups. Postoperative cardiac complications were more common among patients who had a history of congestive heart failure (p = 0.02; odds ratio, 3.75; confidence interval, 1.3 to 11) or reperfusion defects on adenosine thallium scintigraphy (p = 0.01; odds ratio, 3.4; confidence interval, 1.2 to 9.4), regardless of group. CONCLUSIONS Routine use of PACs for perioperative monitoring with the above protocol during aortic surgery is not beneficial and may be associated with a higher rate of intraoperative complications. Preoperative tune up does not prevent postoperative cardiac, renal, and other complications. Variables such as cardiac risk factors and adenosine thallium scintigraphy may be more important predictors of cardiac events in patients who undergo aortic operations.

Early endarterectomy for severe carotid artery stenosis after a nondisabling stroke: Results from the North American Symptomatic Carotid Endarterectomy Trial

PURPOSE The timing of carotid endarterectomy (CE) after a recent nondisabling stroke remains controversial. Delaying surgery in such cases may needlessly place patients at risk for a recurrent stroke that may be major and disabling. This study examines the prognostic implications of performing early endarterectomy compared with delayed endarterectomy in patients from the North American Symptomatic Carotid Endarterectomy Trial. METHOD This retrospective, subgroup analysis involved 100 surgical patients with severe (70% to 99%) angiographically defined carotid artery stenosis, who were diagnosed with a nondisabling hemispheric stroke at entry into the trial. Forty-two CEs were performed within 30 days (early group, ranging 3 to 30 days), and 58 were performed beyond 30 days (delayed group, range 33 to 117 days) after stroke. The risk of subsequent stroke after CE was compared between the two groups. RESULTS Baseline clinical characteristics were comparable in both the early and delayed groups. In the delayed group more lesions were identified ipsilateral to the symptomatic side on the preoperative computed tomography scans. The postoperative (30 days after endarterectomy) stroke rate was 4.8% in the early group and 5.2% in the delayed group, yielding a relative rate of 0.92 (95% confidence interval, 0.16 to 5.27; p = 1.00). No deaths occurred after operation in either group. At the end of 18 months, the rates of any stroke or death were 11.9% and 10.3% for the early and delayed groups, respectively, resulting in a relative rate of 1.15 (95% confidence interval, 0.38 to 3.52; p = 1.00). No association was found between an abnormal preoperative computed tomography scan result and the subsequent risk of stroke when early operation was used. CONCLUSION Early CE for severe carotid artery stenosis after a nondisabling ischemic stroke can be performed with rates of morbidity and mortality comparable to those who receive delayed endarterectomy. Delaying the procedure by 30 days for patients with symptomatic high-grade stenosis exposes them to a risk of a recurrent stroke, which may be avoidable by earlier surgery.

Vein patch versus primary closure for carotid endarterectomy: A randomized prospective study in a selected group of patients

During a 4-year period, 136 patients undergoing 152 carotid endarterectomies consented to be randomized to primary or saphenous vein patch closure of the arteriotomy. At operation, before randomization, careful assessment of arterial dimensions and anatomy was made. Patients who had an internal carotid artery (ICA) diameter less than 5 mm, arteriotomy extending more than 3 cm beyond the origin of the ICA, or tortuous or kinked ICAs were not randomized; they received obligatory vein patch closure (necessary in 20% cases). All patients were followed up every 3 months for 1 year and every 6 months thereafter with duplex scanning, ocular pneumoplethysmography, and neurologic assessment. The incidence of atherosclerotic risk factors was equal in the groups and all except one of the patients were male. Perioperative morbidity was not significantly different among those having primary closure (n = 60), saphenous vein patch closure (n = 62), and obligatory vein patch closure (n = 30). Operative time among patients having primary closure (122 +/- 4 minutes) was significantly less (p less than 0.001) than among those having saphenous vein patch closure (150 +/- 3 minutes). Three perioperative strokes were evenly distributed among the groups (2% for all procedures); no deaths and no acute postoperative occlusions occurred. Recurrent disease occurred in 12.9% of patients having saphenous vein patch closure compared with its occurrence in 1.7% of those having primary closure (p less than 0.05). However, most recurrences were moderate stenoses (25% to 50% diameter reduction), all were smooth-surfaced, and none required a second operation. All except one of the recurrences among those patients with saphenous vein patch closure were in the bulb and the origin of the ICA; two had evidence of regression. This finding suggested that thrombus layering in the dilated part of the saphenous vein patch reconstruction was the cause. This study demonstrates that in men with carotid arteries of predetermined minimal dimensions undergoing carotid endarterectomy routine saphenous vein patch closure does not produce superior results, is associated with a higher incidence of early recurrence, and increases operative time. In selected patients with anatomic risk factors for recurrent disease or acute postoperative occlusion, saphenous vein patch closure is appropriate.

Trends and outcomes of concurrent carotid revascularization and coronary bypass

BACKGROUND The management of concurrent carotid and coronary artery disease is controversial. Although single-center observational studies have revealed acceptable outcomes of combined carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG), community-based outcomes have been substantially inferior. Recently, carotid artery stenting (CAS) has been introduced for the management of high-risk patients with carotid stenosis, including those with severe coronary artery disease. This study was undertaken to evaluate the nationwide trends and outcomes of CAS before CABG vs combined CEA and CABG and to assess the risk for adverse events. METHODS The Nationwide Inpatient Sample (NIS) was used to identify patients discharged after concurrent carotid and coronary revascularization procedures. All patients that underwent CAS before CABG and combined CEA-CABG during the years 2000 to 2004 were included. The type of revascularization and major adverse events (ie, in-hospital stroke and death rates) were determined by cross-tabulating discharge diagnostic and procedural codes. Risk stratification was performed using the Charlson Comorbidity Index. Weighted exact Cochrane-Armitage trend test and multivariate logistic regression were used to assess the association between types of revascularization, comorbidities, complications, and risk-adjusted mortality. RESULTS During the 5-year period, 27,084 concurrent carotid revascularizations and CABG were done. Of these, 96.7% underwent CEA-CABG, whereas only 3.3% (887 patients) had CAS-CABG. From 2000 to 2004, the proportion of patients undergoing CAS-CABG vs CEA-CABG did not significantly changed (P = .27). Patients undergoing CAS-CABG had fewer major adverse events than those undergoing CEA-CABG. CAS-CABG patients had a lower incidence of postoperative stroke (2.4% vs 3.9%), and combined stroke and death (6.9% v. 8.6%) than the combined CEA-CABG group (P < .001), although in-hospital death rates were similar (5.2% vs 5.4%). After risk-stratification, CEA-CABG patients had a 62% increased risk of postoperative stroke compared with patients undergoing CAS before CABG (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.1-2.5; P = .02). However, no differences in the risk of combined stroke and death were observed (OR, 1.26; 95% CI, 0.9-1.6; P = NS). CONCLUSION Although CAS may currently be performed for high-risk patients, it is still infrequently used in patients who require concurrent carotid and coronary interventions. In the United States, patients who undergo CAS-CABG have significantly decreased in-hospital stroke rates compared with patients undergoing CEA-CABG but similar in-hospital mortality. CAS may provide a safer carotid revascularization option for patients who require CABG.

Venous morbidity after superficial femoral-popliteal vein harvest

PURPOSE The superficial femoral-popliteal vein (SFPV) is a reliable conduit for aortoiliac, infrainguinal, and venous reconstructions. In this prospective study, we characterized the anatomic and physiologic changes in SFPV harvest limbs and their relationship to the development of late venous complications. METHODS Since 1990, we have studied 61 patients after harvest of 86 SFPVs at 6-month intervals with clinical examinations, lower-extremity venous duplex, and venous function tests. The CEAP system was used as a means of categorizing clinical changes. RESULTS Mean (+/- SEM) follow-up was 37 +/- 3 months. Less than one third of harvest limbs had edema without skin changes (C3). No patient had major chronic venous changes (C4 to C6) or venous claudication. There were no significant differences in limb measurements between harvest and non-harvest limbs, except in a subgroup of patients with unilateral harvest in which there was a small but significant (P =.046) increase in harvest limb thigh and calf circumference, compared with the opposite non-harvest limb. These clinical results were not affected by the presence or absence of an intact greater saphenous vein (GSV). Large, direct collaterals (4 to 6 mm in diameter) between the popliteal vein stump and profunda femoris vein (PFV) were seen by means of duplex ultrasonography in 29 harvest limbs (34%). The remainder appeared to have smaller, less direct collaterals to the PFV. Mild venous reflux with rapid cuff deflation was present at the popliteal or posterior tibial vein in nine of 79 harvest limbs (11%). Six of these nine limbs (67%) with reflux were clinical class C3, compared with only 19 of the 70 limbs without reflux (27%; P =.02). Ambulatory venous pressure (AVP) with exercise was significantly increased in harvest limbs (60 +/- 4.7 mm Hg), compared with non-harvest limbs (47.8 +/- 5.2 mm Hg; P =.049). The AVP recovery time of harvest limbs (14.0 +/- 1.0 seconds) was reduced, compared with non-harvest limbs (23.5 +/- 4.5 seconds; P =.02). AVPs (exercise) remained stable or decreased in six of 10 harvest limbs measured serially. Venous refill time in harvest limbs (15.1 +/- 1.1 seconds) was shortened, compared with non-harvest limbs (22.3 +/- 2. 1 seconds)(P =.002). Venous outflow obstruction measured by means of plethysmography was present in 93% of harvest limbs, compared with 36% of non-harvest limbs (P =.001). CONCLUSION SFPV harvest results in minimal mid-term to late-term lower-extremity venous morbidity despite outflow obstruction. The most likely mechanisms preserving clinical status include the low incidence of mild reflux, the presence of collateral venous channels, and the lack of progression in abnormal harvest limb physiology. The absence of the ipsilateral GSV does not adversely affect clinical outcome.