Intraoperative assessment of carotid endarterectomy: a comparison of techniques

Intraoperative completion studies in carotid endarterectomy: systematic review and meta-analysis of techniques and outcomes

Background

Declining perioperative stroke and death rates over the past 3 decades have been paralleled by an increasing use of intraoperative completion studies (ICS) following carotid endarterectomy (CEA). Techniques applied include angiography, intraoperative duplex ultrasound (IDUS), flowmetry, and angioscopy. This systematic review and meta-analysis is aiming on providing an overview of techniques and corresponding outcomes.

Methods

A PubMed based systematic literature review comprising the years 1980 through 2020 was performed using predefined keywords to identify articles on different ICS techniques. Pooled analyses and meta-analyses estimating risk ratios (RR) and 95% confidence intervals (CI) were performed to compare outcomes of different ICS modes to nonapplication of any ICS. I² values were assessed to quantify study heterogeneities.

Results

Identification of 34 studies including patients undergoing CEA with angiography (n=53,218), IDUS (n=20,030), flowmetry (n=16,812), and angioscopy (n=2,291). Corresponding rates of perioperative stroke were 1.5%, 1.8%, 3.6%, and 1.5%, perioperative stroke or death occurred in 1.7%, 1.9%, 2.2%, and 2.0%. Intraoperative surgical revision rates were 6.2%, 5.9%, and 7.9% after CEA with angiography, IDUS, and angioscopy, respectively. Compared to nonapplication of any ICS, the pooled analysis revealed angiography to be significantly associated with lower rates of stroke (RR 0.47; 95% CI, 0.36–0.62; P<0.0001) and stroke or death (RR 0.76; 95% CI, 0.70–0.83; P<0.0001). IDUS was significantly associated with lower rates of stroke (RR 0.56; 95% CI, 0.43–0.73; P<0.0001) and stroke or death (RR 0.83; 95% CI, 0.74–0.93; P=0.0018), whereas angioscopy showed a significant association with a lower stroke rate (RR 0.48; 95% CI, 0.033–0.68; P=0.0001), but no effect on the combined stroke or death rate. Angioscopy was associated with a higher intraoperative revision rate compared to angiography (RR 1.29; 95% CI, 1.07–1.54; P=0.006). The meta-analyses confirmed lower perioperative stroke or death rates for angiography (RR 0.83; 95% CI, 0.76–0.91) and IDUS (RR 0.86; 95% CI, 0.76–0.98) compared to non-application of any ICS, whereas flowmetry showed no significant association.

Conclusions

This study represents the first systematic literature review and meta-analysis on usage of ICSs in CEA. Data strongly indicate a significant beneficial effect of angiography, IDUS, and angioscopy on perioperative CEA outcomes. Any carotid surgeon should consider implementation of ICSs in his routine armamentarium.

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.

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.

Prospective Comparison of Duplex Ultrasound and Angiography for Intra-operative Completion Studies after Carotid Endarterectomy

OBJECTIVE

The application of intra-operative completion studies may have contributed to the ongoing improvement of peri-operative outcomes in carotid surgery.

METHODS

This prospective study aimed to compare angiography and duplex ultrasound (IDUS) as intra-operative completion studies after carotid endarterectomy (CEA) with respect to differences in the rating of vessel wall defects and interobserver reliability. Patients undergoing CEA for symptomatic or asymptomatic carotid stenosis were included. After CEA, angiography and IDUS were performed. Intra-operatively obtained video footage was evaluated at a later date by three independent and blinded raters with different levels of clinical experience. Rating was done according to a four step rating scale, with higher grades representing more severe defects. Standard statistical methods (Pearson's chi square test; permutation test; Wilcoxon signed rank test; Kendall's coefficient of concordance, Wt) were applied.

RESULTS

In total, 150 patients (mean ± standard deviation age 72 ± 7 years, 68.7% male, 33.3% symptomatic) were enrolled between March 2016 and September 2017. Significantly more defects requiring intra-operative revision (grades 3 and 4 on rating scale) were detected by IDUS, which, in part, remained undetected by angiography: 22 (14.7%) vs. 10 (6.7%) (p = .040). Defects were also judged to be more severe with IDUS than with angiography: median rating grade 1: 74 (49.3%) vs. 102 (68.0%); grade 2: 54 (36.0%) vs. 38 (25.3%); grade 3: 21 (14.0%) vs. 9 (6.0%); grade 4: 1 (0.7%) vs.1 (0.7%) (p < .001). Furthermore, Wt was significantly higher for IDUS compared with angiography (0.70 vs. 0.57; p = .003).

CONCLUSION

IDUS revealed more defects after CEA than angiography. Despite both techniques only showing moderate interobserver reliability, IDUS is less dependent on the surgeon's subjectivity than angiography. Taking into account the absence of procedure associated risks (i.e., adverse effects of iodinated contrast media and Xray), IDUS could be considered as an alternative intra-operative morphological assessment tool in carotid surgery.

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.

[Will carotid thromboendarterectomy remain competitive? Influence of intraoperative duplex ultrasound quality control]

BACKGROUND

Thromboendarterectomy (TEA) and stenting are in competition for treatment of carotid artery lesions. Both treatment modalities have to improve significantly. The goal of the study was to evaluate the influence of routine intraoperative duplex ultrasound examination.

METHODS

In a continuous prospective study, 575 patients underwent 620 carotid operations. Intraoperative duplex ultrasound examination was performed prior to wound closure: 9.5% had significant contralateral ICA stenoses and 6.7% ICA occlusion; 8.5% presented special lesions. An eversion TEA was performed in 20.5% while 78.5% underwent conventional TEA with patch plasty and graft interposition in 1%. Intraoperative quality control revealed unexpected lesions in 10% requiring immediate repair.

RESULTS

The combined morbidity/mortality rate (MMR) of the total series was 2.6%. Women had an elevated risk (4.2%) in comparison to men (1.9%). The risk of elder patients (>75 years, n=151) was remarkably low. The neurological complication rate of the total series was 1.6% and the incidence of major strokes 1.1%.

CONCLUSIONS

Routine intraoperative duplex ultrasound examination of the carotid reconstruction allows early diagnosis and immediate correction of morphologic as well as hemodynamic lesions. Competing with stent placement a further reduction of complications of carotid TEA seems to be possible and necessary.

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.

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 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.

Computerized tomographic angiography scan following carotid endarterectomy

The purpose of this study was to evaluate the role of computed tomographic angiography (CTA) for postoperative assessment of carotid endarterectomy (CE). Twenty carotid endarterectomies were performed and controlled by using (1) intraoperative angiography, (2) postoperative duplex scanning and CTA with multiprojection volume reconstruction (MPVR). Intraoperative angiographic controls were deemed satisfactory for all patients. In 12 patients, the postoperative morphological aspect was satisfactory with CTA and duplex scanning. In the eight remaining patients, CTA and/or duplex scanning revealed 12 abnormalities: 3 were equally visualized on CTA and duplex scanning, 6 only on CTA and 3 only on duplex scanning. CTA is a rapid and noninvasive technique allowing the surgeon to get informative and comparative data. It might be an interesting alternative to postoperative angiography.