Processes of care for carotid endarterectomy: Surgical and anesthesia considerations

Long-term durability and clinical outcome of a prospective randomized trial comparing carotid endarterectomy with ACUSEAL polytetrafluoroethylene patching versus pericardial patching

BACKGROUND

Several studies have shown the superiority of carotid endarterectomy (CEA) with patch closure over primary closure. However, no definite study has shown any significant differences in clinical outcome between various types of patches. Because more vascular surgeons have used pericardial patching recently, this study will analyze the late clinical outcome (≥10 years) of our previously reported prospective randomized trial comparing CEA with ACUSEAL (polytetrafluoroethylene) vs pericardial patching.

METHODS

A total of 200 CEAs were randomized (1:1) to either Vascu-Guard pericardial patching or ACUSEAL patching. All patients had immediate duplex ultrasound imaging, which was repeated at 6 months and annually thereafter. Kaplan-Meier analysis was used to estimate rates of freedom from stroke, stroke-free survival, and rates of freedom from ≥50% and ≥80% restenosis.

RESULTS

Overall demographic and clinical characteristics were somewhat similar with a mean follow-up of 80 months (range: 0-149 months). The rates of freedom from stroke were 97, 97, 97, 96, 93 for ACUSEAL vs 99, 98, 97, 97, 92 for pericardial patching (P = .1112) at 1, 2, 3, 5, and 10 years, respectively. Similarly, the rates of freedom from stroke/death were 94, 93, 90, 76, 50 for ACUSEAL vs 99, 96, 91, 78, 47 for pericardial patching (P = .8591). The rates of freedom from ≥50% restenosis were 98, 98, 96, 89, 79 for ACUSEAL vs 87, 83, 83, 81, 71 for pericardial patching (P = .0489). The rates of freedom from ≥80% restenosis were 99, 99, 99, 96, 85 for ACUSEAL vs 96, 96, 96, 93, 93 for pericardial patching (P = .9407). The overall survival rates were 95, 94, 91, 77, 51 for ACUSEAL vs 100, 98, 93, 79, 50 for pericardial patching (P = .9123). Other patch complications (eg, rupture, aneurysmal dilation, infection, etc) were similar.

CONCLUSIONS

Both CEA with ACUSEAL (polytetrafluoroethylene) and pericardial patching are durable and have similar clinical outcomes at 10 years except that ACUSEAL patching has significantly better rates of freedom from ≥50% restenosis.

Intraoperative Cerebral Monitoring During Carotid Surgery: A Narrative Review

BACKGROUND

Intra-operative neurological monitoring (IONM) during carotid endarterectomy (CEA) aims to reduce neurological morbidity of surgery.

OBJECTIVE

This narrative review analyses the role and results of different methods of IONM.

METHODS

review articles on PUBMED and Cochrane Library, by searching key words related to IONM and CEA, from 2000 up to date.

RESULTS

regional anesthesia in some centers represents the "gold standard". The most often used alternative techniques are: stump pressure, electroencephalogram, somatosensory evoked potentials, transcranical doppler ultrasound, near infrared spectroscopy and routine shunting. Every technique shows limitations. Regional anesthesia can make difficult prompt intubation when needed. Stump pressure shows a wide operative range. Electroencephalogram is unable to detect ischemia in sub-cortical regions of the brain. Somatosensory evoked potentials certainly demonstrate the presence of cerebral ischemia, but are no more specific or sensitive than the electroencephalogram. Transcranical doppler monitoring is undoubtedly operator-dependent and suffers from the limitations that the probe has to be placed relatively near to the surgical site and may impede the operator, especially if it needs constant adjustments; moreover, an acoustic window may not be found in 10% -20% of the subjects. Near infrared spectroscopy appears to have a high negative predictive value for cerebral ischemia, but has a poor positive predictive value and low specificity, because predominantly estimates venous oxygenation as this makes up about 80% of cerebral blood volume. The data on the use of Routine Shunting (RS) from RCTs are limited.

CONCLUSIONS

currently, with no clear consensus on monitoring technique, choice should be guided by local expertise and complication rates. With reflection, best practice may dictate that a standard technique is selected as suggested above and this remains the default position for individual practice. Nevertheless, current techniques for monitoring cerebral perfusion during CEA are associated with false negative and false positive resulting in inappropriate shunt insertion.

Literature review of primary versus patching versus eversion as carotid endarterectomy closure

BACKGROUND

Which type of closure after carotid endarterectomy (CEA), whether primary, patching, or eversion, will provide the optimal results has remained controversial. In the present study, we compared the results of randomized controlled trials (RCTs) and systematic meta-analyses of the various types of closure.

METHODS

We conducted a PubMed literature review search to find studies that had compared CEA with primary closure, CEA with patching, and/or eversion CEA (ECEA) during the previous three decades with an emphasis on RCTs, previously reported systematic meta-analyses, large multicenter observational studies (Vascular Quality Initiative data), and recent single-center large studies.

RESULTS

The results from RCTs comparing primary patching vs primary closure were as follows. Most of the randomized trials showed CEA with patching was superior to CEA with primary closure in lowering the perioperative stroke rates, stroke and death rates, carotid thrombosis rates, and late restenosis rates. These studies also showed no significant differences between the preferential use of several patch materials, including synthetic patches (polyethylene terephthalate [Dacron; DuPont, Wilmington, Del], Acuseal [Gore Medical, Flagstaff, Ariz], polytetrafluoroethylene, or pericardial patches) and vein patches (saphenous or jugular). The results from observational studies comparing patching vs primary closure were as follows. The Vascular Study Group of New England data showed that the use of patching increased from 71% to 91% (P < .001). Also, the 1-year restenosis and occlusion (P < .01) and 1-year stroke and transient ischemic attack (P < .03) rates were significantly lower statistically with patch closure. The results from the RCTs comparing ECEA vs conventional CEA (CCEA) were as follows. Several RCTs that had compared ECEA with CCEA showed equivalency of CCEA vs ECEA (level 1 evidence) with patching in the perioperative carotid thrombosis and stroke rates. At 4 years after treatment, the incidence of carotid stenosis was lower for ECEA than for primary closure (3.6% vs 9.2%; P = .01) but was comparable between patching and eversion (1.5% for patching vs 2.8% for eversion).

CONCLUSIONS

Routine carotid patching or ECEA was superior to primary closure (level 1 evidence). We found no significant differences between the preferential use of several patch materials. The rates of significant post-CEA stenosis for CEA with patching was similar to that with ECEA, and both were superior to primary closure.

Fluctuations of serum neuron specific enolase and protein S-100B concentrations in relation to the use of shunt during carotid endarterectomy

Objective

To evaluate the changes in serum neuron specific enolase and protein S-100B, after carotid endarterectomy performed using the conventional technique with routine shunting and patch closure, or eversion technique without the use of shunt.

Materials and Methods

Prospective non-randomized study included 43 patients with severe (>80%) carotid stenosis undergoing carotid endarterectomy in regional anesthesia. Patients were divided into two groups: conventional endarterectomy with routine use of shunt and Dacron patch (csCEA group) and eversion endarterectomy without the use of shunt (eCEA group). Protein S-100B and NSE concentrations were measured from peripheral blood before carotid clamping, after declamping and 24 hours after surgery.

Results

Neurologic examination and brain CT findings on the first postoperative day did not differ from preoperative controls in any patients. In csCEA group, NSE concentrations decreased after declamping (P<0.01), and 24 hours after surgery (P<0.01), while in the eCEA group NSE values slightly increased (P=ns), accounting for a significant difference between groups on the first postoperative day (P=0.006). In both groups S-100B concentrations significantly increased after declamping (P<0.05), returning to near pre-clamp values 24 hours after surgery (P=ns). Sub-group analysis revealed significant decline of serum NSE concentrations in asymptomatic patients shunted during surgery after declamping (P<0.05) and 24 hours after surgery (P<0.01), while no significant changes were noted in non-shunted patients (P=ns). Decrease of NSE serum levels was also found in symptomatic patients operated with the use of shunt on the first postoperative day (P<0.05). Significant increase in NSE serum levels was recorded in non-shunted symptomatic patients 24 hours after surgery (P<0.05).

Conclusion

Variations of NSE concentrations seemed to be influenced by cerebral perfusion alterations, while protein S-100B values were unaffected by shunting strategy. Routine shunting during surgery for symptomatic carotid stenosis may have the potential to prevent postoperative increase of serum NSE levels, a potential marker of brain injury.

Carotid endarterectomy in awake patients: safety, tolerability and results

Objective

To analyze the results of 125 carotid endarterectomies under loco-regional anesthesia, with selective use of shunt and bovine pericardium patch.

Methods

One hundred and seventeen patients with stenosis ≥ 70% in the internal carotid artery on duplex-scan + arteriography or magnetic resonance angiography underwent 125 carotid endarterectomies. Intraoperative pharmacological cerebral protection included intravenous administration of alfentanil and dexametasone. Clopidogrel, aspirin and statins were used in all cases. Seventy-seven patients were males (65.8%). Mean age was 70.8 years, ranging from 48 to 88 years. Surgery was performed to treat symptomatic stenosis in 69 arteries (55.2%) and asymptomatic stenosis in 56 arteries (44.8%).

Results

A carotid shunt was used in 3 cases (2.4%) due to signs and symptoms of cerebral ischemia after carotid artery clamping during the operation, and all 3 patients had a good outcome. Bovine pericardium patch was used in 71 arteries ≤ 6 mm in diameter (56.8%). Perioperative mortality was 0.8%: one patient died from a myocardial infarction. Two patients (1.6%) had minor ipsilateral strokes with good recovery, and 2 patients (1.6%) had non-fatal myocardial infarctions with good recovery. The mean follow-up period was 32 months. In the late postoperative period, there was restenosis in only three arteries (2.4%).

Conclusion

Carotid artery endarterectomy can be safely performed in the awake patient, with low morbidity and mortality rates.

Comparison of morphological and rheological conditions between conventional and eversion carotid endarterectomy using computational fluid dynamics – a pilot study

Purpose:

To compare postoperative morphological and rheological conditions after eversion carotid endarterectomy versus conventional carotid endarterectomy using computational fluid dynamics.

Basic methods:

Hemodynamic metrics (velocity, wall shear stress, time-averaged wall shear stress and temporal gradient wall shear stress) in the carotid arteries were simulated in one patient after conventional carotid endarterectomy and one patient after eversion carotid endarterectomy by computational fluid dynamics analysis based on patient specific data.

Principal findings:

Systolic peak of the eversion carotid endarterectomy model showed a gradually decreased pressure along the stream path, the conventional carotid endarterectomy model revealed high pressure (about 180 Pa) at the carotid bulb. Regions of low wall shear stress in the conventional carotid endarterectomy model were much larger than that in the eversion carotid endarterectomy model and with lower time-averaged wall shear stress values (conventional carotid endarterectomy: 0.03–5.46 Pa vs. eversion carotid endarterectomy: 0.12–5.22 Pa).

Conclusions:

Computational fluid dynamics after conventional carotid endarterectomy and eversion carotid endarterectomy disclosed differences in hemodynamic patterns. Larger studies are necessary to assess whether these differences are consistent and might explain different rates of restenosis in both techniques.

Posterior transverse plication of the internal carotid artery to correct for kinking

BACKGROUND

The occasional need for shortening of the internal carotid artery (ICA) following carotid endarterectomy (CEA) to correct for kinking is still controversial. Although several technical options have been suggested, the impact on perioperative outcome remains unclear, and long-term clinical follow-up is lacking. Shortening by resection has a theoretical risk for a twisted anastomosis and subsequent ICA thrombosis. Posterior transverse plication (PTP) offers an alternative shortening technique without the need for a new anastomosis. We aimed to assess the safety and patency of CEA with concomitant PTP. Secondly, we aimed to provide an overview of different technical modalities for shortening of the carotid artery in current literature.

METHODS

Within the time frame of 2000 through 2011, 29 patients (mean age, 73.4 years) undergoing CEA with additional PTP of the ICA and standardized patchplasty were retrospectively identified. Patient characteristics, surgical procedural details, and both short- (<30 days) and long- (>30 days) term clinical and duplex ultrasound follow-up were retrieved. Restenosis was defined as ≥50% stenosis on duplex ultrasound. In addition, a literature search was performed on different techniques for ICA shortening.

RESULTS

Thirty-day outcome revealed no deaths or strokes. No postprocedural thrombosis or narrowing of the ipsilateral ICA was observed. During follow-up (mean, 34.3 months; range, 3-125 months), one patient (4%) died of a noncardiovascular cause. Three patients (11%) developed ipsilateral neurological symptoms (1 stroke, 2 transient ischemic attacks) after 5, 19, and 66 months follow-up, respectively. Of these, two patients (7%) had restenosis at the site of PTP. Asymptomatic restenosis occurred in one other patient (4%) after 16 months.

CONCLUSIONS

Although the indications for additional shortening procedures following CEA need to be defined, in this small series, PTP as an additional shortening procedure of the ICA following CEA seems feasible and safe with no additional periprocedural risk for narrowing at the plicature or thrombosis of the endarterectomy plane. However, restenosis at the plicature may hamper the long term benefit of carotid reconstruction.

Prevention of Intra-operative Cerebral Ischemia during Carotid Endarterectomy, Loco-regional versus General Anesthesia

Carotid endarterectomy (CEA), as a prophylactic operation is becoming more popular. It is performed in patients who are at risk of stroke from dislodged atheromatous plaque at the carotid bifurcation. The major concern during CEA is the detection of cerebral hypoperfusion or ischemia during carotid cross clamping. Some studies have shown that the introduction of loco-regional anesthesia has lowered the incidence of major complications compared with general anesthesia since ischemia detection is easier in conscious patient.

A large and giant bifurcation aneurysm model in canines: proof of feasibility

BACKGROUND AND PURPOSE

To our knowledge, no reproducible animal model of a giant bifurcation type aneurysm has been described. It was our aim to develop a 1-stage and reproducible model of a venous pouch giant aneurysm in canines.

MATERIALS AND METHODS

Nine canines were involved. Bilateral CCAs were exposed. The left CCA was divided and its distal segment was swung to the right side. Using the right CCA and the distal segment of the left CCA, either a bifurcation or a terminal arterial structure was constructed. Bilateral external jugular veins were also exposed. A 30-mm vein segment was harvested from each side. Each vein graft was split and unfolded to make 2 venous sheets. These sheets were then joined top-to-bottom so as to form a single cylinder in such a way that original adventitial side of the venous sheets was on the exterior surface. In 2 instances, pieces of polytetrafluoroethylene were employed along with the venous sheets. The combined vein graft was then incorporated into the arterial anastomosis. Lastly, the top of the venous pouch was closed. No medications for anticoagulant or antiplatelet were used throughout the study period. Follow-up imaging studies were performed.

RESULTS

It took 2.5 hours on average for 2 operators to create an aneurysm. Eight of the 9 aneurysms were patent at follow-up. The cause of the spontaneous thrombosis was unclear despite autopsy. All the aneurysms had a maximum diameter >20 mm.

CONCLUSIONS

We demonstrated and illustrated a 1-stage and reproducible procedure to create a model of a venous pouch bifurcation giant aneurysm in canines.

Clinical, anatomic, and procedural durability of carotid revascularization

Carotid endarterectomy and carotid angioplasty with stenting are 2 common approaches to revascularization. Phase III randomized clinical trials have focused on comparisons of periprocedural outcomes and composite outcomes that combine procedural events and clinical events during follow-up. The comparison of outcomes beyond the perioperative risk period, where the principal concern is durability, defined in clinical, anatomic, and procedural terms, has received less attention. The purpose of this review is to discuss factors that may influence durability and to compare the durability of carotid revascularization techniques beyond the perioperative period using data from randomized clinical trials.

Systematic review of randomized controlled trials of patch angioplasty versus primary closure and different types of patch materials during carotid endarterectomy

OBJECTIVE

Patch angioplasty during carotid endarterectomy (CEA) can reduce the risk of perioperative stroke or late carotid artery recurrent stenosis and subsequent ischaemic stroke. We aimed to update our previous systematic review of randomized controlled trials (RCTs) of routine or selective carotid patch angioplasty compared with CEA with primary closure, and of different materials used for carotid patch angioplasty.

METHODS

We identified new RCTs published during 2002-2010 by searching Medline, Embase and the Cochrane Stroke Group Trials Register. We also hand-searched six relevant journals. Pooled estimates of treatment effects combined with our previous review (1966-2001) were calculated on the basis of a weighted estimate of the odds ratio (OR) with the Peto method.

RESULTS

Twenty-three eligible RCTs were identified in both periods. Ten RCTs involving 2,157 operations compared primary closure with routine patch closure. Patch closure significantly reduced the combined risk of perioperative stroke and later stroke during long-term follow-up [OR = 0.49, 95% confidence interval (CI) = 0.27-0.90, p = 0.001; 7 RCTs]. Patching also reduced the risks of perioperative arterial occlusion (OR = 0.18, 95% CI = 0.08-0.41, p < 0.0001; 7 RCTs) and recurrent stenosis during long-term followup (OR = 0.24, 95% CI = 0.17-0.34, p < 0.001; 8 RCTs).

CONCLUSION

Meta-analysis of relatively small RCTs suggests that carotid patch angioplasty reduces the combined perioperative and long-term risk of stroke and the risk of restenosis. More data are needed.

Carotid Endarterectomy With Primary Closure: Analysis of Outcomes and Review of the Literature

Background:

Despite abundant published support of patch angioplasty during carotid endarterectomy (CEA), primary closure is still widely used. The reasons underlying the persistence of primary closure are not quite evident in the literature.

Objective:

To present our experience with primary closure in CEA, and provide a rationale for its persistent wide use.

Methods:

Medical records of all patients undergoing CEA by the senior author (R.F.) were retrospectively reviewed. Follow-up was supplemented with a telephone interview and completion of a structured questionnaire. A review of the current literature was performed.

Results:

From 1998 to 2010, the senior author performed 111 CEAs. Average cross-clamp time was 33 ± 11 minutes. Postoperative complications included 1 non– ST-elevation myocardial infarction and 2 strokes. No deaths, cranial-nerve deficits, or acute reocclusions were observed. After a mean follow-up of 64.6 months (7170.6 case-months), there were 3 contralateral strokes and 7 deaths. There were no ipsilateral strokes or restenoses &gt;50%. Follow-up medication compliance was 94.6% for anti-platelet agents and 91.9% for statins. The outcomes of the current study were comparable to those of the available trials comparing patch angioplasty with primary closure. A careful evaluation of the literature revealed a number of reasons potentially explaining the persistent use of patch angioplasty.

Conclusion:

In conjunction with contemporary medical management, primary closure during CEA may yield results comparable or superior to patch angioplasty. Advantages of primary closure include shorter cross-clamp times and elimination of graft-specific complications.