The importance of intraoperative detection of residual flow abnormalities after carotid artery endarterectomy

Applications of intraoperative Duplex ultrasound in vascular surgery: a systematic review

Objective

This review aims to summarise the contemporary uses of intraoperative completion Duplex ultrasound (IODUS) for the assessment of lower extremity bypass surgery (LEB) and carotid artery endarterectomy (CEA).

Methods

We performed a systematic literature search using the databases of MEDLINE. Eligible studies evaluated the use of IODUS during LEB or CEA.

Results

We found 22 eligible studies; 16 considered the use of IODUS in CEA and 6 in LEB. There was considerable heterogeneity between studies in terms of intervention, outcome measures and follow-up. In the assessment of CEA, there is conflicting evidence regarding the benefits of completion imaging. However, analysis from the largest study suggests a modest reduction in adjusted risk of stroke/mortality when using IODUS selectively (RR 0.74, CI 0.63–0.88, p = 0.001). Evidence also suggests that uncorrected residual flow abnormalities detected on IODUS are associated with higher rates of restenosis (range 2.1% to 20%). In the assessment of LEB, we found a paucity of evidence when considering the benefit of IODUS on patency rates or when considering its utility as compared to other imaging modalities. However, the available evidence suggests higher rates of thrombosis or secondary intervention in grafts with uncorrected residual flow abnormalities (up to 36% at 3 months).

Conclusions

IODUS can be used to detect defects in both CEA and LEB procedures. However, there is a need for more robust prospective studies to determine the best scanning strategy, criteria for intervention and the impact on clinical outcomes.

Practice patterns in the use of completion imaging after carotid endarterectomy

BACKGROUND

The use of intraoperative completion imaging (completion carotid duplex ultrasound or angiography) to confirm the technical adequacy of carotid endarterectomy (CEA) remains a matter of controversy. The purpose of this study was to describe vascular surgeons' practice patterns in the use of completion imaging after CEA and to study the association between completion imaging and postoperative stroke/death and high-grade restenosis (>70%).

METHODS

Patients who underwent CEA without concomitant procedures in the Vascular Quality Initiative database between 2003 and 2018 were included. Surgeons' practice patterns were defined on the basis of the distribution of completion imaging use among annual CEA cases per surgeon. Multivariable and Cox proportional hazards models were used to study the association between different practice patterns of completion imaging and perioperative and 1-year outcomes after CEA.

RESULTS

Of 98,055 CEA cases, 26,716 (27.3%) were performed with completion imaging. Compared with cases in which completion imaging was not performed, completion imaging was associated with increased rates of immediate re-exploration (3.5% vs 0.9%; odds ratio [OR], 3.84; 95% confidence interval [CI], 2.74-5.38; P < .001), overall return to the operating room (RTOR; 1.6% vs 1.2%; OR, 1.24; 95% CI, 1.08-1.42; P < .01), and longer operative time (median [interquartile range], 105 minutes [82-132] vs 119 minutes [92-148]; P < .001). Of 1920 surgeons in our cohort, 45% never performed completion imaging, whereas 26% rarely performed completion imaging (for ≤20% of annual CEA cases), 9.5% performed it selectively (21%-79% of annual CEAs), and 19.6% used completion imaging routinely (≥80% of annual CEAs). Rarely performing completion imaging had higher rates of immediate re-exploration (6.5% vs 0.9%; OR, 7.2; 95% CI, 5.7-9.2; P < .001), in-hospital stroke (4.0% vs 1.1%; adjusted OR [aOR], 3.4; 95% CI, 2.6-4.6; P < .001), RTOR for bleeding (1.9% vs 0.9%; aOR, 2.1; 95% CI, 1.5-2.9; P < .001), and neurologic events (1.5% vs 0.4%; aOR, 3.6; 95% CI, 2.2-5.9; P < .001) compared with not performing completion imaging. It was also associated with increased stroke/death and repeated revascularization at 30 days and significant restenosis at 1 year. On the other hand, performance of selective and routine completion imaging was associated with increased immediate re-exploration (selective: aOR, 3.2 [95% CI, 1.9-5.5; P < .001]; routine: aOR, 3.7 [95% CI, 2.5-5.6; P < .001]) without any increase in in-hospital, 30-day, and 1-year adverse outcomes compared with cases performed without completion imaging.

CONCLUSIONS

The performance of selective or routine completion imaging during CEA is safe and is not associated with increased adverse events compared with not using intraoperative completion imaging. However, rarely performing completion imaging is associated with a significant increase in the odds of perioperative stroke/death and RTOR, possibly because of unnecessary re-exploration for minor defects. The operator's experience and establishing a criterion for fixing residual defects are important to avoid unnecessary re-exploration.

Completion imaging techniques and their clinical role after carotid endarterectomy: Systematic review of the literature

BACKGROUND

Completion imaging has been suggested for the intraoperative quality control assessment of the carotid endarterectomy technical success, in order to immediately resolve pathologic findings and accordingly improve patients' outcome. The aim of this study was to present existing evidence of different completion imaging techniques after carotid endarterectomy and their role on clinical outcome.

MATERIAL AND METHODS

A systematic review was performed searching in MEDLINE, CENTRAL, and Cochrane databases including studies reporting on completion imaging techniques after carotid endarterectomy.

RESULTS

A total of 12,378 patients in 35 studies (20 retrospective and 15 prospective) underwent a completion imaging technique after carotid endarterectomy: in 19 studies, 5340 patients underwent arteriography; in 5 studies, 2095 angioscopy; in 21 studies, 5722 DUS; and in 2 studies, 150 patients underwent transcranial Doppler. Ten studies assessed > 1 imaging technique. The mean age was 67 ± 7 years old (69% males) with common co-morbidities to be hypertension (74%), smoking (64%), and hyperlipidemia (54%). Almost half of the patients (4949; 44%) were treated for symptomatic disease. In 1104 (9.7%) patients, a major defect was identified intra-operatively, while in 329 patients (2.9%), a minor defect. Common pathological findings were the presence of mural thrombus, carotid dissection, residual stenosis, and intimal flaps. An immediate re-intervention was undertaken in 75% (790/1053) of the patients to treat a major intra-operative imaging finding. In patients with re-intervention, only 2.3% (14/609) had an intra-operative stroke and 0.8% (5/609), a transient ischemic attack, while only 1.4% (8/575) had a stroke and 0.2% a transient ischemic attack (1/575) during 30-day post-operative period. No intra-operative death was reported. In the same period, the restenosis rate of internal and common carotid artery was 0.5% (3/575) and 0.2% (1/575), respectively.

CONCLUSION

Completion imaging techniques can detect defects in almost 10% of patients that may lead to immediate intra-operative surgical revision with low intra-operative stroke/transient ischemic attack rate and low early carotid restenosis. During the 30-day follow-up period, in those patients, the incidence of stroke/transient ischemic attack may be low but present. This review cannot provide any evidence on which completion imaging technique is better, and the clinical impact conferred by each technique in the absence of a randomized control studies.

Role of Residual Defects Following Carotid Endarterectomy in the Occurrence of Cerebrovascular Symptoms

Carotid endarterectomy deals successfully with carotid atheromatous lesions, thus eliminating a potential source of cerebral emboli. At times, however, residual hemodynamic irregularities may occur as a result of technique imperfection or anatomic variations. These irregularities have been associated with a number of immediate and late postoperative complications, such as recurrent cerebrovascular symptoms and secondary episodes of stroke. For this reason, the detection of flow abnormalities or intimal defects in patients undergoing carotid endarterectomy and the achievement of normal intraoperative and postoperative hemodynamics are essential for the elimination of potentially life-threatening perioperative and late cerebrovascular events.

Use of intraoperative duplex ultrasonography for identification and patch repair of kinking stenosis after carotid endarterectomy: a single-surgeon retrospective experience

OBJECTIVE

To provide an incidence and descriptive evaluation of kinking of the internal carotid artery (ICA) after carotid endarterectomy (CEA) in a consecutive CEA series that included the use of intraoperative duplex ultrasonography (IDUS) monitoring and to determine the effect of kink patch repair on long-term postoperative ICA restenosis.

METHODS

The electronic medical records and IDUS recordings of all CEA cases performed over a 10-year period (March 2000 to October 2010) by a single neurosurgeon were retrospectively reviewed to assess cases of kinking after CEA.

RESULTS

IDUS assisted in the identification of 27 of 285 cases (9.5%) of kinking after CEA. Kinked vessels with hemodynamically significant peak systolic velocities of ≥ 120 cm/second on IDUS (11 of 285 cases; 3.9%) were repaired using a synthetic patch. During follow-up, there were no neurologic symptoms, stroke, or death related to a cerebrovascular accident associated with kinking. The total incidence of postoperative stroke in this CEA series was 3 of 285 cases (1.1%).

CONCLUSIONS

ICA kinking stenosis after CEA was a common finding in this CEA series. Because of their unique anatomic and hemodynamic properties, the identification and assessment of kinks after CEA required the use of IDUS monitoring. A selective patch closure method for kinked vessels with peak systolic velocities of ≥ 120 cm/second identified by IDUS was effective in resolving hemodynamically significant stenosis and minimizing long-term postoperative restenosis.

Eight-year experience with carotid artery stenting for correction of symptomatic and asymptomatic post-endarterectomy defects

BACKGROUND

Carotid endarterectomy (CEA) has been shown to be superior to medical therapy alone in the prevention of stroke only if it can be safely performed (ie, with a complication rate less than 3% in asymptomatic patients and less than 6% in symptomatic patients). Technical defects are the most common cause of neurological complications after CEA, and their correction has traditionally been performed through standard surgical techniques.

METHODS

From 1999, we started to treat intimal flaps, dissection, or partial thrombosis after CEA with carotid artery stenting (CAS). A retrospective analysis of the operating room registry and of the registry of our Interventional Cardiology laboratory was conducted in order to identify all the patients that underwent stenting of the internal carotid artery after CEA between January 2001 and June 2009.

RESULTS

During the time period considered, 5012 CEA were performed at our institution and a total of 34 patients (34/5012; 0.6%) were found to have received carotid stenting after CEA, both for symptomatic and asymptomatic defects. Immediate technical success was obtained in all patients. One major cerebrovascular adverse event (1/34; 3%) in the immediate perioperative period was recorded. At a mean follow-up of 18.6 months (range, 3-84 months; median, 12 months), we did not observe any neurological symptoms related to the treated carotid artery, nor hemodynamic in-stent restenosis. Long-term follow-up (ie, equal or greater than 4 years) was available for five patients: all patients remained event-free during the entire period.

CONCLUSIONS

Our study adds to the assumption that CAS in post-CEA symptomatic and asymptomatic patients is safe and technically feasible, and represents a valid and quick alternative to standard surgical revision. Even if in a small group of patients, long-term results seem promising.

Completion imaging after carotid endarterectomy in the Vascular Study Group of New England

OBJECTIVES

We studied surgeons' practice patterns in the use of completion imaging (duplex or arteriography), and their association with 30-day stroke/death and 1-year restenosis after carotid endarterectomy (CEA).

METHODS

Using a retrospective analysis of 6115 CEAs, we categorized surgeons based on use of completion imaging as rarely (<5% of CEAs), selective (5% to 90%), or routine (≥90%). Crude and risk-adjusted 30-day stroke/death and 1-year restenosis rates were examined across surgeon practice patterns. Finally, we audited 90 operative reports of patients who underwent re-exploration and characterized findings and interventions. We analyzed the effect of re-exploration on outcomes.

RESULTS

Practice patterns in completion imaging varied: 51% of surgeons performed completion imaging rarely, 22% selectively, and 27% routinely. Crude 30-day stroke/death rates were highest among surgeons who routinely used completion imaging (rarely: 1.7%; selectively: 1.2%, routinely: 2.4%; P = .05). However, after adjusting for patient characteristics predictive of stroke/death, the effect of surgeon practice pattern was not statistically significant (odds ratio [OR] for routine-use surgeons, 1.42; 95% CI, 0.93-2.17; P = .10; selective-use surgeons, 0.75; 95% CI, 0.40-1.41; P = .366). Stenosis >70% at 1 year showed a trend toward lowest rates for surgeons who performed completion imaging (rarely: 2.8%, selectively: 1.1%, and routinely: 1.1%; P = .09). This effect became statistically significant for selective-use surgeons after adjustment (hazard risk [HR] for selective-use surgeons, 0.52; 95% CI, 0.29-0.92; P = .02). Overall, 178 patients (2.9%) underwent operative re-exploration. Routine-use surgeons were most likely to perform re-exploration (7.6% routine, 0.8% selective, 0.9% rare; P < .001). An audit of 90 re-explored patients demonstrated technical problems, the most common being flap, debris, and plaque. Rates of stroke/death were higher among patients who underwent re-exploration (3.9% vs 1.7%; P = .03); however, this affect was attenuated after adjustment (OR, 2.1; 95% CI, 0.9-5.0; P = .08).

CONCLUSIONS

The use of completion imaging during CEA varies widely across our region. There is little evidence that surgeons who use completion imaging have lower rates of 30-day stroke/death, although selective use of completion imaging is associated with a small but a significant reduction in stenosis 1 year after surgery. We also demonstrate an association between re-exploration and higher risk of 30-day stroke/death, although this effect was attenuated after adjustment for patient-level predictors of stroke/death. Future work is needed to direct the selective use of completion imaging to prevent stroke, rather than cause unnecessary re-exploration.

Routine Completion Angiography during Carotid Endarterectomy is not Mandatory

OBJECTIVE

Intraoperative quality control after carotid endarterectomy (CEA) has been advocated to improve the results of surgical treatment of extracranial carotid artery disease. The aim of this study was to evaluate the usefulness of completion angiography (CA) in prevention of stroke and restenosis after CEA in a single center experience.

MATERIALS AND METHODS

Data concerning 914 consecutive CEAs performed in 3 years (2000-2002) were prospectively collected in a dedicated database. Patients were divided into two groups: in the first group (mandatory-CA group; 430 cases) CA was routinely carried out, except in presence of contraindications to iodinate contrast agents; in the second group (selective-CA group, 484 cases) CA was performed only in selected cases, at surgeon's discretion.

RESULTS

There were no significant differences between the two groups in terms of neurological complications at awakening (0.5% in mandatory-CA group and 0.4% in selective-CA group; p=n.s.) and in 30-day stroke and death rate (1.9% and 1.4%, respectively; p=n.s.). A surgical revision on the basis of CA findings was performed in 5 cases in mandatory-CA group and in 2 cases in selective-CA group (1.2% and 0.4%, respectively; p=n.s.). In the second group, the conditions significantly associated with the need for CA examination were internal carotid near-occlusion, preoperative symptoms, shunt insertion, kind of surgical reconstruction, redo surgery. Estimated absence of ipsilateral stroke and absence of restenosis at 18 months was 98.9% and 89.7% in mandatory-CA group and 99.3% and 93.4% in selective-CA group (p=n.s.) respectively.

CONCLUSIONS

Based on our experience, routine CA following CEA is not suggested. A policy of selected CA at the surgeon's discretion seems to make the intervention safe and durable as well.

Cost-effectiveness of Intraoperative Imaging in Carotid Endarterectomy

OBJECTIVE:

There has never been a large, randomized controlled trial to assess the impact of intraoperative imaging on the success of carotid endarterectomy (CEA). This comparison involves cost-effectiveness analysis.

METHODS:

We constructed a decision-analytic model to compare effectiveness and costs of intraoperative ultrasound (IUS) and completion angiography as adjuncts to CEA. Data on procedural mortality, morbidity, and costs were obtained from the English-language literature. The review included a total of 52 reports, encompassing more than 22,000 patients. The main components of costs were those of the monitoring interventions and the care of perioperative stroke.

RESULTS:

Mean perioperative outcome without completion imaging is approximately 96.7% of what it would be in the absence of perioperative stroke or death. IUS and completion angiography each result in approximately 2% improvement in expected outcome. Mean perioperative costs are $396.50 for IUS, $721.30 for no monitoring, and $840.90 for completion angiography. Because IUS is significantly more effective at detecting technical errors that would likely result in perioperative stroke than no imaging and is significantly less costly than angiography, this strategy dominates the other two (i.e., it provides greater effectiveness at lower cost).

CONCLUSION:

Although surgical complications are uncommon, IUS substantially lowers the rate of perioperative stroke and mortality and thus is significantly more cost-effective than either completion angiography or no operative imaging.

Intraoperative carotid artery duplex scanning in a modern series of 650 consecutive primary endarterectomy procedures

PURPOSE

Thromboembolic complications after carotid endarterectomy are frequently associated with technical defects. We analyzed the effect of intraoperative duplex scanning in detection of significant but clinically unsuspected technical defects and residual common carotid artery (CCA) disease as a potential source of postoperative transitory ischemic attack (TIA) and stroke.

METHODS

From April 2000 to April 2003, 650 consecutive primary carotid endarterectomy procedures were performed in 590 patients at a single institution by two vascular surgeons. Patients included 335 men (57%) and 255 women (43%). Indications for surgery were asymptomatic internal carotid artery (ICA) stenosis (>or=70%) in 464 patients (71%). All procedures were performed with the patient under general anesthesia, with synthetic patch angioplasty in 644 (99.1%). Major technical defects at intraoperative duplex scanning (>30% luminal internal carotid artery stenosis, free-floating clot, dissection, arterial disruption with pseudoaneurysm) were repaired. CCA residual disease was reported as wall thickness (0.7-4.8 mm; mean, 1.7 +/- 0.7) and percent stenosis (16%-67%; mean, 32% +/- 8%) in all cases. Postoperative 30-day TIA, stroke, and death rates were analyzed.

RESULTS

There were no clinically detectable postoperative thromboembolic events in this series. All 15 major defects (2.3%) identified with duplex scanning were successfully revised. These included 7 intimal flaps, 4 free-floating clots, 2 ICA stenoses, 1 ICA pseudoaneurysm, and 1 retrograde CCA dissection. Diameter reduction ranged from 40% to 90% (mean, 67 +/- 16%), and peak systolic velocity ranged from 69 to 497 cm/s (mean, 250 +/- 121 cm/s). Thirty-one patients (5%) with the highest residual wall thickness (>3mm) in the CCA and 19 (3%) with the highest CCA residual diameter reduction (>50%) did not have postoperative stroke or TIA. Overall postoperative stroke and mortality rates were 0.3% and 0.5%, respectively; combined stroke and mortality rate was 0.8%. One stroke was caused by hyperperfusion, and the other occurred as an extension of a previous cerebral infarct. No patients had TIAs. Two deaths were caused by myocardial infarction, and one death by respiratory insufficiency.

CONCLUSION

We believe intraoperative duplex scanning had a major role in these improved results, because it enabled detection of clinically unsuspected significant lesions. Residual disease in the CCA does not seem to be a harbinger of stroke or TIA.

Intraoperative duplex ultrasound of visceral revascularizations: optimizing technical success and outcome

PURPOSE

The purpose of this study was to evaluate the use of intraoperative duplex ultrasound scanning (IOUS) during visceral revascularizations and correlate its results with clinical outcome.

METHODS

We studied 68 patients (15 men and 53 women, mean age 66.5 years, range 27-86 years) who underwent visceral revascularization with concomitant IOUS examination of 120 visceral arteries (52 celiac, 60 superior mesenteric, and 8 inferior mesenteric arteries) from 1992 to 2002. Patients were divided into two groups on the basis of ultrasound findings: normal and abnormal IOUS. The incidence of early and late graft-related complications (thrombosis, restenosis, recurrent symptoms, reintervention) and graft-related death was compared in both groups.

RESULTS

One-hundred and two (85%) arteries had normal IOUS. Eight (6.6%) arteries had minor defects, including small kinks (4), mild residual stenoses (3), and small intimal flap (1). Ten (8.4%) arteries had major defects, consisting of hemodynamically significant residual stenoses (4), thrombus (2), kinks (2), bidirectional flow (1), and intimal flap (1). Major defects were successfully revised in all except three cases: two persistent mild stenoses and one bidirectional flow. Patients with abnormal IOUS at the end of the operation had increased incidence of graft-related complications and/or death (55.5% vs 7.8%; P =.004), early graft thrombosis (14.2% vs 1.0; P =.04), reintervention (21.4% vs 3.2%; P =.03), and graft-related death (33.3% vs 1.9%; P =.02), compared with patients with normal IOUS.

CONCLUSION

This study supports the routine use of IOUS during visceral revascularizations to optimize technical success and outcome. Persistent ultrasound scanning abnormalities are associated with risk of early graft failure, reintervention, and death. Patients with normal ultrasound scans can expect excellent results.

Intraoperative duplex ultrasonography as an adjunct to technical excellence in 100 consecutive carotid endarterectomies

PURPOSE

To evaluate the relationship of intraoperative duplex ultrasonography (duplex) results to neurologic outcomes and restenosis among patients undergoing carotid endarterectomy (CEA).

METHODS

One hundred consecutive CEAs were performed at a military medical center over 28 months. Prospectively acquired demographics, duplex results, revisions, and surgical outcomes were reviewed.

RESULTS

Thirty-four percent (34 of 100) of sites were abnormal by completion duplex. Of these, 70% (24 of 34) were B-mode flap type defects located in the common carotid artery (CCA), internal carotid artery (ICA), or external carotid artery (ECA). Twenty-one percent of the defects (7 of 34) were technically unacceptable and immediately revised. Subsequently, 3 perioperative neurologic events occurred, 2 strokes and 1 transient ischemic attack (TIA), all among patients with an identified but unrepaired defect involving the ICA or CCA. This association of unrepaired defect with early stroke or TIA was significant (P = 0.02). No significant association (P >0.05) between unrepaired defects and late ipsilateral stroke or TIA or restenosis was identified.

CONCLUSIONS

Intraoperative duplex scanning is a useful adjunct to CEA that can identify correctable mechanical problems. Residual elevated velocities or B-mode flaps 2 mm or greater in the ICA warrant consideration for immediate repair. Findings not requiring revision include flaps <2 mm, as well as isolated ECA defects. Prospectively validated duplex criteria are needed to further define which defects require immediate repair.

Importance of a arteriography for intraoperative quality control during carotid artery surgery

The purpose of this study was to determine the impact of intraoperative quality control using arteriography on the conduct and immediate outcome of carotid artery surgery. This retrospective study included 623 carotid artery repair procedures performed between January 1993 and January 2000. There were 427 men and 159 women (37 bilateral procedures) with a mean age of 71.6 years. The repair technique consisted of conventional endarterectomy alone in 353 cases, conventional endarterectomy with patch closure in 95 cases, eversion in 44 cases, and vein (n = 105) or prosthetic (n = 26) grafting in 131 cases. Findings of intraoperative arteriography, which is used routinely in our department, were reviewed and analyzed in all cases. Our findings indicate that intraoperative quality control with arteriography is an important part of carotid artery surgery. In 11.7% of cases in this study, intraoperative arteriography revealed significant defects that are the main cause of postoperative neurological complications.

Correlation of intra-operative duplex findings during carotid endarterectomy with neurological events and recurrent stenosis at one year

OBJECTIVES

Carotid endarterectomy has been used to treat both asymptomatic and symptomatic disease and this has meant that recurrent stenosis and its effect on late stroke risk have become increasingly important. In this study we compared anatomical defects and residual stenosis identified intra-operatively with recurrent stenosis and new symptoms developing in the first year after surgery.

DESIGN, MATERIALS & METHODS

Two hundred and forty-four consecutive patients undergoing carotid endarterectomy were studied prospectively. Residual anatomical defects were noted; residual stenosis was defined by intra-operative duplex ultrasound as >50%. New stenoses and clinical events during the one-year surveillance period were documented.

RESULTS

There was an increased incidence of recurrent stenosis at one year in vessels with residual stenoses (p<0.001) and in vessels containing a residual anatomical defect (p=0.037). There was no significant difference in recurrent stenosis rate with respect to closure (primary or patch) or seniority of surgeon but recurrent stenosis was increased in females (p=0.026). The majority (70%) of restenotic lesions were localised to the origin of the internal carotid artery. The late stroke rate was 0.9% and was not related to recurrent stenosis or symptoms.

CONCLUSIONS

Residual stenosis and intra-luminal defects at completion increase the recurrent stenosis rate at one year. The aetiology of recurrent stenosis is multi-factorial and further studies are required to determine whether it is justified to modify the criteria for re-exploration with a view to reducing recurrent stenosis.

Internal carotid artery flow volume measurement and other intraoperative duplex scanning parameters as predictors of stroke after carotid endarterectomy

PURPOSE

Intraoperative duplex scanning (IDS) after carotid endarterectomy (CEA) has been shown to reliably identify major defects either by significant changes in peak systolic velocities or by B-mode imaging. To evaluate whether IDS could also predict postoperative strokes in technically flawless CEAs, we analyzed several hemodynamic parameters and correlated them with patient outcome.

METHODS

From March 2000 to February 2001, 226 consecutive primary CEAs were performed in 208 patients (120 men). Of these, 153 lesions were asymptomatic. General anesthesia and synthetic carotid artery patches were used routinely. Intraluminal shunts were used when internal carotid artery (ICA) back-pressures were <50 mm Hg (35% of cases). IDS consisted of B-mode and color-flow imaging and spectral analyses of the common, external, and internal carotid arteries. Volume flows were measured three times, and the mean flow rate was used for this study.

RESULTS

The first set of data was analyzed when the twenty-ninth patient had the second immediate postoperative stroke. It was noted that the two patients who had postoperative strokes had mean ICA volume flows (MICAVF) of 48 mL/min and 85 mL/min. Only two additional patients had MICAVF <100 mL/min. The remaining 25 cases had MICAVF ranging from 102 to 299 mL/min, with a mean of 165 +/- 57 mL/min (+/-SD) (P <.02). Although there was a significant correlation between MICAVF and ICA peak systolic velocity (P <.01), the latter was not found to be a significant predictor of postoperative stroke. Moreover, end-diastolic velocities, resistive index, ICA diameter, and ICA back-pressure also did not correlate with neurologic events. These findings led us to change our protocol for patients with MICAVF <100 mL/min. This included a repeat set of volume flow measurements after 15 to 20 minutes, withholding the reversal of heparin, and the liberal use of completion arteriography. Of the following 197 CEAs, 26 (13%) were found to have MICAVF <100 mL/min (range 55 to 99 mL/min; mean 79 +/- 18 mL/min). Of these, five had arteriography that documented spasm of the intracranial portion of the ICA in four and a small-diameter ICA (<2 mm) in one. Except for the five cases, the remaining 21 cases had MICAVF >100 mL/min (range 105 to 158 mL/min, mean 127 +/- 20 mL/min [+/-SD]) on repeat study. Four patients with persistent ICA low flow (70 to 99 mL/min) were treated with postoperative anticoagulation. One of the last 197 patients had a stroke caused by hyperperfusion syndrome 2 weeks after operation. Overall, six of 226 cases (2.7%) required revision on the basis of abnormal B-mode imaging results or peak systolic velocities >150 cm/s. There were two common carotid artery flaps, two ICA stenoses, one ICA flap, and one localized thrombus. All six were successfully revised and had repeat normal IDS study results, and none of these patients had a postoperative stroke.

CONCLUSIONS

IDS is helpful in identifying residual lesions or defects that may contribute to postoperative neurologic deficits. MICAVF <100 mL/min are suggestive of spasm that could lead to thrombus formation and stroke, particularly in the presence of synthetic patches. We suggest that heparin reversal should not be used unless ICA flow rates are >100 mL/min. ICA spasm is short lived in most patients undergoing CEA.

Carotid artery patch angioplasty: impact and outcome

Our study objective was to determine if patch angioplasty after carotid endarterectomy decreases the incidence of post-reconstruction technical defects and recurrent stenosis. This was a retrospective review of a prospectively maintained database from February 1980 to February 2000. Main outcome measures included incidence of intraoperative technical defects, residual disease within 3 months of endarterectomy, and early/late carotid restenosis >50%. During the study period, 71% (1053) of patients had primary closure and 29% (435) had patch closure. Immediate post-reconstruction intraoperative imaging with angiography or duplex ultrasound was accomplished in all cases. Technical defects prompted the reopening of 136 (13%) carotid arteries closed primarily but only 9 (2%) of those that were patched (p < 0.0001). There were no instances of residual disease in either group. Overall rate of recurrent stenosis was 2%, 3%, and 3.5% at 5, 10, and 15 years, respectively by life-table analysis. Early and late restenosis was significantly reduced by patch angioplasty (p = 0.024 and 0.006, respectively). This study demonstrates that carotid artery patch angioplasty significantly reduces the incidence of detectable technical defects and the early/late recurrent stenosis rate.

Comparison of intraoperative and postoperative duplex ultrasound for carotid endarterectomy

Intraoperative (IO) duplex ultrasound (DU) is used to identify correctable technical defects at the time of carotid endarterectomy (CEA). Postoperative (p.o.) DU is used to evaluate recurrent or residual stenosis. We compared IO and p.o. DU to determine the value and significance of these studies in the management of patients undergoing CEA. We performed completion IO DU following CEA and p.o. DU a mean of 8 weeks after surgery in 78 patients. IO studies were performed by the operating surgeon and p.o. studies were performed in an accredited vascular laboratory. Peak systolic velocity (PSV) was measured in the internal carotid (ICA), external carotid, and common carotid (CCA) arteries. The criteria used for an abnormal study were an ICA PSV > 150 cm/sec and a ratio of ICA to CCA PSVs(ICA/CCA) > 3.0. Completion angiograms were also performed on all patients intraoperatively. Technical defects identified on DU or angiogram were corrected whenever possible. From our results, we concluded that in many patients, early p.o. DU will demonstrate an elevated ICA PSV compared to the IO PSV. If the ICA/CCA remains normal, this increase is unlikely to represent a clinically relevant recurrent or residual stenosis. A postoperative ICA/CCA ratio > 3.0 may be a more reliable indicator of significant stenosis and a lesion that is likely to progress or occlude than PSVs alone.

Intraoperative duplex ultrasound during carotid endarterectomy

The purpose of this study was to examine the technical aspects of intraoperative duplex ultrasound (DUS) following carotid endarterectomy (CEA), suggest criteria to differentiate significant lesions requiring immediate surgical revision from normal or benign defects, and evaluate how frequently intraoperative DUS provides useful or unsuspected information. A retrospective study was performed on all patients who had both CEA and intraoperative carotid DUS between January 1, 1990, and January 1, 1995. A total of 155 DUS examinations were performed in 149 patients. Findings were grouped into three categories: normal; minor/insignificant lesions; and hemodynamically significant lesions based on the presence or absence of elevated peak systolic velocities, visible stenosis/thrombus, or intimal flap/dissection. Postoperative status was correlated with intraoperative DUS findings. Ninety-one (59%) examinations performed on 87 patients produced normal findings. Forty-seven (30%) examinations performed on 45 patients showed minor abnormalities consisting of insignificant residual plaque, residual external carotid artery stenoses, small intimal flaps, elevated velocities with no associated anatomic lesion, or an arterial kink. Fourteen patients (9%) had significant findings requiring immediate surgical revision. These consisted of large intimal flaps or dissection in six patients, marked residual plaque and significant stenosis in five patients, thrombus in two patients, and a kink in one patient. Three additional patients (2%) had significant findings but were not revised for various reasons. No significant difference was identified in morbidity or mortality rates between those patients with normal findings, those patients with minor technical defects, and those patients with significant abnormalities undergoing immediate surgical revision. However, two of three patients who had significant abnormalities within the common carotid artery that were not revised suffered perioperative ipsilateral strokes. Intraoperative DUS is a safe and accurate method to assess the technical adequacy of CEA. Intraoperative DUS showed significant lesions in 11% of patients. Identification and immediate repair of significant technical defects may decrease perioperative complication rate and long-term restenosis rate.

Frequency of postoperative carotid duplex surveillance and type of closure: results from a randomized trial

BACKGROUND/PURPOSE

In several nonrandomized studies investigators have reported on the value of postoperative carotid duplex surveillance (PCDS) with mixed results; however the type of closure was not analyzed in these studies. In this study we analyze the frequency and timing of postoperative carotid duplex ultrasound scanning according to the type of closure from a randomized carotid endarterectomy (CEA) trial comparing primary closure (PC) versus patching.

PATIENT POPULATION AND METHODS

We randomized 399 CEAs into 135 PCs, 134 polytetrafluoroethylene (PTFE) patch closures, and 130 vein patch closures (VPCs) with a mean follow-up of 47 months. PCDS was done at 1, 6, and 12 months and every year thereafter (a mean of 4.0 studies per artery). Kaplan-Meier analysis was used to estimate the rate of > or = 80% restenosis over time and the time frame of progression from < 50%, to 50%-79% and > or = 80% stenosis.

RESULTS

Restenoses of > or =80% developed in 24 (21%) arteries with PC and nine (4%) with patching. Kaplan-Meier estimate of freedom of > or = 80% restenosis at 1, 2, 3, 4, and 5 years was 92%, 83%, 80%, 76%, and 68% for PC, respectively, and 100%, 99%, 98%, 98%, and 91% for patching, respectively, (P <.01). Of 56 arteries with 20% to 50% restenosis, two of 28 patch closures and 10 of 28 PCs progressed to 50% to < 80% restenosis (P =.02); none of the patch closures and six of 28 PCs progressed to > or =80% (P =.03). In PCs, the median time to progression from <50% to 50%-79%, < 50% to > or =80%, and 50%-79% to > or = 80% was 42, 46, and 7 months, respectively. Of the 24 arteries with > or =80% restenosis in PC, 10 were symptomatic. Thus, assuming th symptomatic restenosis would have undergone duplex scan examinations regardless, there were 14 asymptomatic arteries (12%) that could have been detected only with PCDS (estimated cost, $139, 200), and those patients would have been candidates for redo CEA. Of the 9 arteries (3 PTFE closures and 6 VPCs) with > or =80% restenosis with patch closures, 6 asymptomatic (4 VPCs and 2 PTFE closures) arteries (3%) could have been detected with PCDS. In patients with normal duplex scan findings at the first 6 months, only four (2%) of 222 patched arteries (two asymptomatic) developed > or = 80% restenosis versus five (38%) of 13 in patients with abnormal duplex scan examination findings (P<.001).

CONCLUSIONS

PCDS is beneficial in patients with PC, but is less beneficial in patients with patch closure. PCDS examinations at 6 months and at 1- to 2-year intervals for several years after PC are adequate. For patients with patching, a 6-month postoperative duplex scan examination with normal results is adequate.

A rational algorithm for duplex scan surveillance after carotid endarterectomy

PURPOSE

This study was undertaken to determine the appropriate timing and frequency of duplex ultrasound scanning after carotid endarterectomy (CEA) for the detection of high-grade stenosis caused by recurrent carotid stenosis or contralateral atherosclerotic disease progression.

METHODS

In 221 patients who underwent 242 CEAs, duplex scanning was performed before, during, and after operation (in 3-month to 6-month intervals). High-grade internal carotid artery (ICA) stenosis (peak systolic velocity, >300 cm/s; diastolic velocity, >125 cm/s; ICA/common carotid artery ratio, >4) prompted the recommendation for repair. An average of four postoperative scanning procedures was performed during a mean follow-up period of 27.4 months.

RESULTS

Intraoperative duplex scan results prompted the immediate revision of 12 repairs (4.9%), and one perioperative stroke (<1%) occurred. Six CEAs (2.7%) had asymptomatic recurrent stenosis (>50% diameter-reduction [DR]; systolic velocity, >125 cm/s) develop. Only one of six patients had >75% DR stenosis develop and underwent reoperation (<1% yield for CEA surveillance). The yield of surveillance of the unoperated ICA was higher (P =.003), and 12% of unoperated sides had progressive stenosis (n = 21) or occlusion (n = 3) develop, which led to seven CEAs for high-grade stenosis. Disease progression to >75% DR stenosis was five times as frequent (P =.002) in patients with >50% DR stenosis initially. All patients but one who required contralateral endarterectomy for disease progression had >50% ICA stenosis when first seen. During the follow-up period, no disabling strokes ipsilateral to an operated carotid artery occurred, but three strokes occurred in the hemisphere of the contralateral unoperated ICA.

CONCLUSION

The yield of duplex scan surveillance after CEA was low. Only 13 patients (5.9%) had severe disease develop to warrant additional intervention. Progression of contralateral disease rather than restenosis was the most common abnormality that was identified. Duplex scanning at 1-year to 2-year intervals after CEA is adequate when a technically precise repair is achieved and minimal contralateral disease (<50% DR) is present. A policy of duplex scan surveillance and reoperation for high-grade stenosis was associated with a 1.6% incidence rate of disabling stroke during the follow-up period.

Use of intraoperative duplex ultrasonography and routine patch angioplasty in patients undergoing carotid endarterectomy

OBJECTIVE

To determine the value of routine patch angioplasty and intraoperative duplex ultrasonography (US) during carotid endarterectomy (CEA) for high-grade internal carotid artery stenosis.

PATIENTS AND METHODS

The charts of 102 consecutive patients who underwent CEA with routine patching and intraoperative duplex US for treatment of high-grade carotid stenosis between June 1991 and January 1997 were reviewed retrospectively. Recurrent stenosis was defined as a narrowing in the common or internal carotid artery of more than 40%.

RESULTS

Of 102 patients, 65 (63.7%) were men, and 37 (36.3%) were women (mean age, 72.4 years). Thirteen patients (12.7%) had bilateral CEAs. Intraoperative duplex US revealed abnormalities during 29 (25.2%) of 115 CEAs; 14 abnormalities (12.2%) were major and underwent immediate revision. No perioperative neurologic events or deaths occurred. Mean length of follow-up was 21.3 months (range, 1.3-72.6 months). Late neurologic events occurred in 2 patients, and 5 patients died during follow-up. All neurologic events and deaths were unrelated to the patients' carotid surgery. Twelve patients (11.8%) developed moderate restenosis (40%-69%). In 4 of these patients restenosis resolved during further follow-up. No patient developed severe recurrent carotid stenosis.

CONCLUSION

Morbidity and mortality following CEA with routine patch angioplasty and intraoperative duplex US appear to be low. Routine intraoperative duplex US detects correctable technical problems that subsequently lead to a low incidence of symptomatic stenosis. The low incidence of recurrent stenosis suggests that routine postoperative follow-up may not be necessary or cost-effective unless the patient has symptoms or a contralateral stenosis.

Intraoperative assessment of technical perfection in carotid endarterectomy: a prospective analysis of 1305 completion procedures. Collaborators of the EVEREST study group. Eversion versus standard carotid endartectomy

OBJECTIVE

to define the incidence of technical defects and the impact of technical errors on ipsilateral carotid occlusion, ipsilateral stroke, and early restenosis rates, we analysed 1305 patients undergoing carotid completion procedures.

DESIGN

prospective multicentre study.

PATIENTS AND METHODS

adequacy of CEA was assessed intraoperatively by angiography in 1004 (77%), by angioscopy in 299 (22%), and by duplex scan in two patients (1%). Arteriograms and angioscopic findings were interpreted at the time of the procedure by the operating surgeon, who also established the need for immediate surgical revision.

RESULTS

perioperatively, 13 major strokes (0.9%, all ipsilateral) and six deaths (0.4%) were recorded. Overall, 112 defects (9%) were identified intraoperatively: 81 (72%) were located in the common carotid artery (CCA) or internal carotid artery (ICA), and 31 (28%) in the external carotid artery. In 48 patients (4%) the defects were revised. Logistic regression analysis revealed that carotid plaque extension >2 cm on the ICA was a positive independent predictor of CEA defects (odds ratio (OR) 1.5p=0.03). A significant association was found between the incidence of revised defects of the CCA and ICA and perioperative ipsilateral stroke (OR 11.5p=0.0002). In contrast, patients with minor non-revised defects had an ipsilateral stroke rate comparable to that of patients with no defects (p=0.4). No significant association was found between revised or non-revised defects and occurrence of restenosis/occlusion at 6-month follow-up.

CONCLUSIONS

the incidence of major technical defects during CEA is low, yet the perioperative neurological prognosis of patients with major defects warranting revision is poor. Completion angiography or angioscopy and possible correction of defects did not protect per se from an unfavourable early outcome after CEA. Therefore, surgical excellence is mandatory to achieve satisfactory results after CEA.

Timing and frequency of perioperative carotid color-flow duplex scanning: A preliminary report

PURPOSE

The results of intraoperative and early postoperative carotid color-flow duplex scanning (CFS) after endarterectomy were reviewed to determine whether any perioperative studies could be eliminated.

METHODS

Patients undergoing carotid endarterectomy with intraoperative CFS between 1986 and 1997 were identified. Early postoperative CFS was performed between 1 day and 3 weeks postoperatively, then it was performed again at 6 months postoperatively.

RESULTS

During the study period, 560 patients, 325 men and 235 women, underwent 621 carotid endarterectomies. A satisfactory intraoperative carotid CFS was completed in 611 (98.4%) patients. There were 20 (3.2%) vessels with a major defect that required revision for fronds or flaps (n = 11), retained atheroma (n = 5), low flow (n = 2), high velocity or turbulence (n = 1), or dissection (n = 1). Another 146 vessels (23.5%) had minor defects, such as retained proximal atheromas or small (less than 3 mm) fronds, but were not revised. The remaining 445 vessels were normal. The first postoperative CFS was normal in all the revised carotids and in 138 (94.5%) vessels with minor intraoperative defects. At 6 months, recurrent stenosis (more than 75% area reduction) was identified in 1 of 18 revised carotids (5.5%), 4 of 138 vessels (2. 9%) with minor defects, and 17 of 406 vessels (4.2%) that were normal intraoperatively. The incidence of recurrent stenosis was not significantly different in the three groups (P =.7).

CONCLUSION

Intraoperative CFS is useful because major unsuspected defects can be corrected immediately, thus avoiding potential neurologic morbidity. However, the postoperative day 1 CFS can be eliminated in most cases, because it does not provide any relevant clinical information.

Intraoperative duplex scanning for carotid endarterectomy

OBJECTIVES

To evaluate the results of intraoperative duplex scans during carotid endarterectomy.

DESIGN

Retrospective case review.

MATERIALS

One-hundred consecutive intraoperative carotid duplex scans performed during carotid endarterectomy between July 1993 and December 1995 at a university teaching hospital.

METHODS

Abnormalities of the B-mode image and/or the Doppler flow analysis were classified. The result of intraoperative carotid duplex scans (ICDS) were related to the events of the intraoperative course, perioperative neurologic morbidity and mortality, and to residual carotid stenosis.

RESULTS

Abnormalities of the ICDS were demonstrated in 13 cases (13%). Abnormalities were classified into four types: I, internal carotid artery spasm (n = 9); II, high distal resistance flow (n = 2); III, high grade residual stenosis (n = 1); IV, intraluminal thrombosis (n = 1). Immediate intraoperative exploration and revision of the endarterectomy was performed based on the ICDS in two cases (type III and IV) and the findings of ICDS were confirmed. The other 11 cases with abnormal ICDS (types I, II) were not revised and duplex scans done 1 month postoperatively (available in 10 cases) showed normal carotid artery flow. Intraoperative angiography was performed selectively in five cases and confirmed the results of ICDS. Reversible abnormalities of the ICDS were not associated wit perioperative morbidity or residual carotid stenosis.

CONCLUSIONS

Intraoperative carotid duplex scanning can be used to assess the immediate technical adequacy of carotid endarterectomy. B-mode image and Doppler flow abnormalities which are reversible can be distinguished from those which require immediate revision.

Intraoperative high resolution duplex imaging during carotid endarterectomy: which abnormalities require surgical correction?

OBJECTIVES

This study evaluates high resolution, duplex ultrasound imaging for quality control of carotid endarterectomy in order to determine which technical factors were linked to residual stenosis and to define duplex criteria for re-exploration.

DESIGN, MATERIAL AND METHODS

A consecutive series of 100 patients undergoing carotid endarterectomy were evaluated. Duplex imaging was performed prior to wound closure and repeated at 6-8 weeks postoperatively. Stenoses were classified as non-significant, moderate or severe based on duplex criteria. Intimal flaps, shelves, kinks, clamp damage and fronds were identified by ultrasound imaging.

RESULTS

Five moderate stenoses were noted in the proximal endarterectomy site (PES), and at follow-up three had resolved. Adherent fronds were detected in 83% of vessels and resolved in all but three cases. At the distal endarterectomy site there were 10 severe and 12 moderate stenoses. Intimal flaps were associated with an increased incidence of residual stenosis (p = 0.010).

CONCLUSIONS

We conclude that severe stenoses with an intimal flap should be corrected immediately. Further data is required to establish the significance of kinks. Residual intimal flaps in the PES appear to remodel. The role of completion duplex may lie in the modification of surgical technique to eradicate anatomical and haemodynamic imperfections.

Vascular ultrasound

Surgeon-interpreted diagnostic ultrasound has become the preferred screening test and often the definitive test for the diagnosis of arterial stenosis, aneurysm, and venous thrombosis. As a modality for surveillance, its noninvasive quality makes it particularly appealing as the test of choice to screen patients for abdominal aortic aneurysms or to perform follow-up examinations on those patients with a carotid endartectomy or in situ bypass grafts. The increasing reliance on intraoperative duplex imaging of vascular procedures demands that the surgeon learn the skills to perform the studies without a technologist or radiologist to interpret the examination.

Carotid recurrent stenosis and risk of ipsilateral stroke: a systematic review of the literature

BACKGROUND

The main goal of follow-up after carotid endarterectomy is to prevent new strokes caused by recurrent stenosis. To determine the most cost-effective follow-up schedule, it is necessary to know the incidence of recurrent stenosis and the risk of stroke it carries.

METHODS

A systematic review of the literature was performed using standard meta-analytical techniques.

RESULTS

Incidence of recurrent stenosis: The data were very heterogeneous. The risk of recurrent stenosis was 10% in the first year, 3% in the second, and 2% in the third. Long-term risk of recurrent stenosis is about 1% per year. Risk of stroke: The reported relative risks of stroke in patients with recurrent stenosis compared with patients without recurrent stenosis showed extreme heterogeneity and ranged from 10 to 0.10. The random effects summary estimator of relative risk was 1.88.

CONCLUSIONS

The data were very heterogeneous, and much better data are needed to arrive at truly reliable estimates of these important parameters of follow-up. It is clear, though, that the risk of recurrent stenosis is highest in the first few years after carotid endarterectomy and very low in later years. By use of general decision-analytic arguments, it can be argued that, given the test characteristics of carotid ultrasound, a small number of tests can be done in the first few years and that testing for restenosis should not be done after 4 years.

Conservative management of residual and recurrent lesions after carotid endarterectomy: long-term results

PURPOSE

To document the natural history of residual and recurrent carotid stenoses that are initially treated without surgery, and to identify risk factors for recurrent stenosis.

METHODS

Review of data from a prospective carotid database with clinical and duplex follow-up. Analysis of rate of restenosis and rate of late reoperation by life table. Risk factor analysis by chi 2 and LEE-DESU statistics.

RESULTS

Three hundred forty-eight patients were available for follow-up, with 12 residual lesions (3.7%) and 22 recurrent lesions (6.6%). Rate of recurrent stenosis by life table analysis was 8.7% and 13% at 3 and 5 years. Restenosis was associated with smoking (p = 0.04) and contralateral progression. Only 21% of patients were underwent an operation within 5 years (p = 0.007) of restenosis developing, but eventually 10 of 22 patients required reoperation at long-term follow-up, eight for symptoms and two for progressive proximal stenoses. The late stroke rate was increased in patients who had residual or recurrent lesions compared with those who had normal duplex study results (18% vs 6%; p = 0.16) and was related to the ipsilateral artery.

CONCLUSIONS

Recurrent lesions that remain asymptomatic can be managed without operation with likelihood of success in the near term (5 years). However, these patients are at increased risk of late stroke, and almost half will eventually require operation. Therefore, in good-risk patients operation for asymptomatic restenosis should be considered.

Completion angiography, is it really necessary?

BACKGROUND

Routine completion imaging after carotid endarterectomy (CEA) has been advocated by many investigators to detect and repair unsuspected defects with the goal of reducing perioperative morbidity and residual disease. However, completion imaging has been performed rarely in our practice. Our carotid registry was interrogated to determine whether omitting routine completion imaging adversely affected outcome.

METHODS

A retrospective review of 229 consecutive CEAs performed by one vascular surgeon during 1988 to 1996 was completed. Duplex follow-up was used to identify persistent residual defects, which were classified as 50% to 74%, 75% to 99%, and occlusion in the common (CCA), internal (ICA), and external (ECA) arteries and was available in 192 cases.

RESULTS

During the study period, eight completion angiograms were performed (3.5%) and 5 arteries were reopened. Combined stroke and death rate was 3.1% (7 of 229). Duplex follow-up, available on 192 patients, showed residual lesions in 29 patients (15%), but only 7 (3.6%) involving the internal or common carotid.

CONCLUSION

Routine completion imaging is not required to achieve acceptable morbidity and mortality and minimize residual problems after CEA. Attention to operative details with selective imaging will give excellent results.

Factors contributing to recurrent carotid disease following carotid endarterectomy

BACKGROUND

Retrospective analysis was performed to assess the effect of gender, age, hypertension, diabetes, and smoking upon residual disease, recurrent disease, and progression of disease following carotid endarterectomy (CE). The effect of patch versus primary closure was also studied.

METHODS

Postoperative duplex studies were performed following 323 CEs at months 1, 6, 12, and 24. Residual disease was defined as luminal stenosis >59% at 1 month. Progression of disease was defined as stenosis at any month that was greater than stenosis at month 1. Recurrent disease was nonresidual stenosis >79%.

RESULTS

Correlation was found between age at operation <65 years and cigarette smoking; both also correlated with progression of disease on serial studies, as well as recurrent stenosis <79%. Primary closure of the arteriotomy correlated with residual disease.

CONCLUSION

Primary closure of the arteriotomy following CE increases the likelihood of residual disease. Smokers and those aged <65 years are predisposed to progression of postoperative disease, and to development of recurrent stenosis.

Duplex imaging findings predict stenosis after carotid endarterectomy

PURPOSE

This study was performed to determine whether early duplex findings predicted restenosis after carotid endarterectomy.

METHODS

One hundred ninety-two symptomatic patients who underwent carotid endarterectomy were studied with color duplex imaging at 1 day and 1 week after surgery to identify minor residual disease (causing < 50% stenosis), arterial kinking, and suture stricture, and to measure the external and luminal diameters of the carotid bulb and distal internal carotid artery. Patients were then observed prospectively with duplex surveillance for a median of 24 months to identify > 50% restenosis.

RESULTS

Twenty-five stenoses > 50% of the operated carotid artery (13%) were identified, four at 1 day (residual) and 21 at a median follow-up of 6 months (restenosis). On multiple logistic regression analysis, > 50% restenosis was found to be associated with minor day-1 residual stenosis (p = 0.01) and with small luminal diameter of the distal internal carotid artery (p = 0.03) as measured 1 week after carotid endarterectomy. Life table analysis showed restenosis at 24 months to be more common for patients with below-median than patients with above-median carotid bulb external diameter (18% vs 5%, respectively; p = 0.01).

CONCLUSIONS

Duplex scanning within a week of carotid endarterectomy identifies > 50% residual stenosis, in addition to minor residual 25% to 50% stenosis and small carotid dimensions, which are good predictors of > 50% restenosis at 6 months.

Relationship between intraoperative color-flow duplex findings and early restenosis after carotid endarterectomy: a preliminary report

PURPOSE

This study was undertaken to examine the relationship between intraoperative color-flow duplex (CFD) findings and the development of restenosis in patients undergoing carotid endarterectomy (CEA).

METHODS

Seventy-eight patients (43 male and 35 female; mean age, 65 years) underwent 86 CEAs (eight staged bilateral) and intraoperative CFD during a 31-month period. Three patients (three CEAs, 3%) underwent both CFD and a completion arteriographic scan. Patients were observed in a postoperative protocol using CFD surveillance. The follow-up interval ranged from 6 to 24 months (average, 12 months).

RESULTS

After undergoing CEA, 10 patients (10 CEAs, 11%) had an abnormality detected by intraoperative CFD; one was confirmed with a completion arteriographic scan. These abnormalities consisted of elevated peak systolic velocities (PSV) with a mosaic color pattern suggesting turbulence seen in six CEAs, including one internal carotid artery (ICA) with abnormal hemodynamics and an unremarkable completion arteriogram. Intimal defects on B-mode were seen in another four CEAs. These carotid arteries were reexplored, defects (intimal flaps with platelet thrombus) were confirmed by direct examination, and all were repaired with or without a patch (six ICAs, three external carotid arteries, and one common carotid artery). No cerebrovascular events occurred in the perioperative period. No carotid restenosis (> or = 50% diameter reduction) was identified during follow-up of 43 patients (48 CEAs, 56%). Two patients had recurrent neurologic symptoms.

CONCLUSION

Intraoperative CFD is an effective test for detecting flow abnormalities or intimal defects in patients undergoing CEA. Ensuring normal intraoperative hemodynamics after CEA may be a major factor associated with decreased incidence of perioperative cerebrovascular events and subsequent carotid artery restenosis.

The fate of residual defects following carotid endarterectomy detected by early postoperative duplex ultrasound

BACKGROUND

The purpose of this study is to evaluate the results of color-flow duplex ultrasound (CFD) soon after carotid endarterectomy (CEA) to determine the incidence of residual abnormalities and their effect on subsequent outcome and management.

METHODS

We reviewed 318 consecutive CEAs performed over a 48 month-period. Of these, 206 were followed up with CFD, 195 prior to discharge and 11 at first follow-up (within 9 weeks). Patients (43) followed up with only oculoplethysmography (OPG) or those with no OPG or CFD (69) were excluded from the study. All CEAs were performed under general anesthesia with routine shunting and patch angioplasty.

RESULTS

Twelve of the 206 studies (5.8%) were abnormal. Two patients with an abnormal CFD sustained perioperative stroke, both of whom had distal intimal lesions of > 60% diameter stenosis by velocity criteria. Four patients had > 60% stenosis and were reoperated upon to correct technical errors. The remaining 6 patients are asymptomatic. Four had residual lesions of < 60% stenosis, three of which have returned to normal on subsequent CFD. Two residual lesions had > 60% stenosis; one returned to normal by CFD and the other remains abnormal at 10 months. In the group of 192 normal postoperative CFD studies, there were no strokes, deaths, or redo procedures (0%, 95% confidence interval 0% to 1.54%) compared with a combined 50% rate (6 of 12) of either stroke (2 of 12) or redo procedure (4 of 12) when the postoperative CFD was abnormal (95% confidence interval 22.3% to 77.7%, P < 0.0001). During the study period the CEA stroke rate was 0.9% (3 of 318), with a combined stroke-mortality rate of 1.3% (4 of 318).

CONCLUSIONS

Early postoperative CFD identified residual abnormalities in 5.8% of carotid endarterectomies despite a low overall stroke mortality rate. One half of these abnormalities resulted in stroke or required operative correction. Colorflow duplex ultrasound is useful in identifying residual abnormalities following CEA and should be considered for intraoperative use.

The role of intra-operative duplex imaging in arterial reconstructions

BACKGROUND

This study is a cost-benefit analysis of a less invasive method of intra-operative duplex imaging compared with the use of intra-operative angiogram (including C-arm fluoroscopy) in arterial reconstruction.

METHODS

From September 1994 to May 1995, 93 intra-operative duplex imaging studies were performed. Duplex scanning results were recorded for carotid endarterectomy (35), iliac balloon angioplasty and stent placement (12), and infra-inguinal bypass (46). Average cost and time were calculated for each type of study.

RESULTS

Thirty-four carotid endarterectomy patients (97%) had normal duplex findings. Three (9%) underwent intra-operative angiogram due to abnormal duplex findings and post-operative neurological deficit. In iliac balloon angioplasty and stent placement cases (12), both intra-operative duplex and C-arm post-stent angiography yielded comparable results in both normal (11) and abnormal (1) studies. In infra-inguinal bypass cases (46), 2 had abnormal duplex findings of the native vessels. Average time and cost required to perform intra-operative duplex studies is significantly less than that required for intra-operative angiogram or C-arm studies.

CONCLUSION

Compared with traditional intra-operative angiography, the use of intra-operative duplex imaging is less expensive, less invasive, quicker, and equally accurate when used as an adjunct to access surgical results of arterial reconstructions.

An outcome analysis of carotid endarterectomy: the incidence and natural history of recurrent stenosis

PURPOSE

This report identifies the incidence of recurrent carotid stenosis after carotid endarterectomy (CEA) and records the natural history of the disease process to gain further insight into its proper management.

METHODS

A prospective surveillance protocol with duplex imaging and velocity spectral analysis was used to detect recurrent stenosis ( > 50% diameter reduction) and to document the clinical outcomes of patients who underwent CEA. Between 1984 and 1993, 619 consecutive CEAs were performed in 587 patients.

RESULTS

Recurrent carotid stenosis developed in 48 CEA sites (7.8%) during a mean follow-up interval of 34 months (range, 2 to 118 months). Normal results on intraoperative assessment correlated with a 5.6% incidence of recurrent stenosis, compared with a 19% incidence when a residual hemodynamic abnormality was present (p < 0.0003). In the first year after surgery, there were no transient ischemic attacks, strokes, or carotid occlusions from recurrent stenosis, compared with a 27% morbidity rate in later follow-up (p < 0.01). Three patients with recurrent stenosis subsequently had occlusion at the CEA site, two of whom had severe ipsilateral strokes.

CONCLUSIONS

The incidence of recurrent carotid stenosis is low. Patients are at significant risk for neurologic morbidity when a recurrent stenosis occludes. With a 0.3% incidence of late stroke resulting from carotid bifurcation disease, these data confirm that CEA does provide long-term protection from stroke.

Intraoperative duplex scanning as a means of quality control during carotid endarterectomy

OBJECTIVES

To identify correctable technical errors following carotid endarterectomy using intraoperative colour duplex sonography (ATL, UM9, HDI). Results were compared with intraoperative flow measurements using an operative flow meter and with middle cerebral artery velocity measured by trans-cranial Doppler (TCD).

DESIGN

Prospective study.

MATERIALS AND METHODS

50 consecutive patients undergoing carotid endarterectomy were investigated. Follow-up was performed at 6 weeks using duplex scanning and clinical evaluation.

RESULTS

Significant intraoperative technical errors were detected in three patients and were re-explored. Two scans demonstrated kinking or pinching at the distal endarterectomy site requiring patch-plasty and the third revealed a large mass of intramural thrombus. A further 18 endarterectomies yielded 21 additional minor abnormalities.

CONCLUSIONS

Duplex sonography provides a sensitive intraoperative technique for detecting thrombus and technical errors. It yields both anatomic and hemodynamic details and is superior to intraoperative flow measurements and transcranial doppler.

Intraoperative duplex scanning of arterial reconstructions: fate of repaired and unrepaired defects

PURPOSE

Because unrecognized lesions can cause an arterial reconstruction to fail, duplex ultrasonography was evaluated as an intraoperative aid to assess technical adequacy and provide criteria for which lesions should be repaired immediately versus safely followed.

METHODS

Since 1990 intraoperative color duplex scanning(7 to 10 MHz linear array probe, pulsed-wave Doppler test spectrum analysis) was used to assess the frequency and severity of residual lesions in 368 patients after carotid endarterectomy (n = 210), infrainguinal vein bypass (n=135) or visceral/renal reconstruction (n = 23). Duplex scan results were categorized as normal or abnormal, with immediate repair of lesions demonstrating both lumen reduction and severe focal flow abnormalities (peak systolic velocity [Vp] > 150 to 180 cm/sec;velocity ratio [Vr] > 2.4). Arteriography was also performed in 81% of lower limb bypass procedures.

RESULTS

Duplex scanning identified technical (residual plaque, stricture) or intrinsic defects (platelet thrombus, distal thrombosis) requiring revision in 37 (10%) of the reconstructions. Infrainguinal bypass had the highest incidence of corrected defects (14%) and adverse events (3%). No adverse events occurred in patients with normal duplex scan results or after carotid endarterectomy. Overall, 76% of identified defects were corrected (carotid, 17 of 24; infrainguinal bypass, 19 of 24; visceral bypass, 1 of 1). Unrepaired flow defects (Vp = 150 to 190 cm/sec; Vr = 1.8 to 2.5) led to one graft occlusion and three early revisions. Postoperative duplex scanning demonstrated residual stenosis in seven of 12 patients with unrepaired defects, two of 36 patients with repaired defects, and five of 312 patients with normal scan results (p < 0.001).

CONCLUSION

Based on the types of lesions corrected and the low (< 0.5%) complication rate after a normal or modified arterial reconstruction, duplex scanning was found to be a valuable intraoperative aid. Unrepaired defects require close surveillance for progression.

Routine completion study during carotid endarterectomy is not necessary

The results of many studies have suggested the need for a completion study during carotid endarterectomy (CE). This paper describes our experience not routinely using completion studies. We retrospectively reviewed the charts of 417 patients who underwent 455 CEs. Demographic features, risk factors, ipsilateral neurologic events during the first 30 days, and mortality data were identified. There were 14 neurologic events and 4 deaths. No technical defects were found in 13 patients; 1 patient did not have exploratory surgery after an occlusion. Long-term follow-up shows 10 of the 14 arteries are open. Two patients were lost to follow-up, 1 patient died, and 1 artery was not explored. We conclude that CE may be carried out without routinely using a completion study, with an acceptable postoperative neurologic complication rate. Careful technique is mandatory.

Intraoperative duplex monitoring of the carotid bifurcation for the detection of technical defects

OBJECTIVES

Intraoperative Duplex examination can be used to identify technical imperfections during carotid endarterectomy. The objectives of this study were: (1) to evaluate the technical feasibility of intraoperative Duplex; (2) to compare Duplex findings with contrast arteriography; (3) to correlate intraoperative Duplex findings with postoperative complications and with Duplex data obtained during follow-up.

DESIGN

Prospective clinical study.

SETTING

Department of Vascular Surgery, Catharina Hospital, Eindhoven, The Netherlands.

MATERIALS

44 patients underwent Duplex scanning at the completion of carotid endarterectomy. In addition intraoperative arteriography was performed in the first 16 consecutive patients. Follow-up included a Duplex examination at three monthly intervals during the first postoperative year.

OUTCOME MEASURES

Technical defects and flow disturbance at the time of surgery, and postoperative restenosis.

RESULTS

At contrast arteriography a distal intimal ridge with 15-20% diameter reduction was observed in two, an occlusion of the external carotid artery in three and moderate kinking in one patient. All abnormalities were identified at Duplex imaging. In none of the cases were the Duplex findings considered an indication to re-explore the endarterectomised internal carotid artery. Postoperative complications occurred in six patients: three strokes, two transient ischaemic attacks and two internal carotid occlusions (in one patient combined with a stroke). Severe spectral broadening (spectral class D) correlated significantly with early postoperative complications (p = 0.027). In contrast, moderate defects on Duplex imaging did not correlate significantly with early complications. Duplex examination during the first year of follow-up demonstrated recurrent stenosis in four patients. Intraoperative spectral broadening did not correlate significantly with the development of common or internal carotid restenosis. However, external carotid recurrent stenosis was positively related to intraoperative flow disturbance (p = 0.0003).

CONCLUSION

Duplex scanning is easy to use after completion of carotid endarterectomy. There is good agreement between intraoperative Duplex scanning and contrast arteriography. Extensive spectral broadening of the Doppler velocity signal is associated with an increased prevalence of early postoperative complications. Restenosis at follow-up appears to be related to severe flow disturbance as was demonstrated for the external carotid artery.