Registry Report on Kinetics of Rescue Antiplatelet Treatment to Abolish Cerebral Microemboli After Carotid Endarterectomy

Tirofiban combined with heparin's effect and safety in the treatment of mild to moderate acute ischemic stroke

Tirofiban can be used to treat patients with acute ischemic stroke (AIS), this study was to evaluate the efficacy and safety of tirofiban combined with heparin in the treatment of mild to moderate AIS. A total of 98 patients with mild to moderate AIS randomly were divided into 2 groups within 48 h: the treatment group treated with tirofiban and, and the control group treated with aspirin + clopidogrel. The treatment group was given the same scheme as the control group after the treatment of tirofiban combined with heparin for 48 h. It was found that, compared with the control group, a significant decreased National Institute of Health stroke scale (NIHSS) was found in 48 h and 14 d, especially to the Barthel index (BI) in the treatment group (P < 0.05). Furthermore, Modified Rankin Scale (MRS, ≤2) in the treatment group was significantly upregulated in 90 d (P < 0.05). However, there were no significant differences in the adverse drug reactions between the two groups. It was indicated that nerve function and long-term prognosis in patients undergoing heparin for mild to moderate AIS were obviously improved than the control group.

Perioperative Stroke

PURPOSE OF REVIEW

This review overviews perioperative stroke as it pertains to specific surgical procedures.

RECENT FINDINGS

As awareness of perioperative stroke increases, so does the opportunity to potentially improve outcomes for these patients by early stroke recognition and intervention. Perioperative stroke is defined to be any stroke that occurs within 30 days of the initial surgical procedure. The incidence of perioperative stroke varies and is dependent on the specific type of surgery performed. This chapter overviews the risks, mechanisms, and acute evaluation and management of perioperative stroke in four surgical populations: cardiac surgery, carotid endarterectomy, neurosurgery, and non-cardiac/non-carotid/non-neurological surgeries.

Registry report on prediction by Pocock cardiovascular score of cerebral microemboli acutely following carotid endarterectomy

Background

Cerebral microemboli may lead to ischaemic neurological complications after carotid endarterectomy (CEA). The association between classical cardiovascular risk factors and acute cerebral microemboli following carotid surgery has not been studied. The aim of this study was to explore whether an established cardiovascular risk score (Pocock score) predicts the presence of cerebral microemboli acutely after CEA.

Subjects and methods

Pocock scores were assessed for the 670 patients from the Carotid Surgery Registry (age 71±1 (SEM) years, 474 (71%) male, 652 (97%) Caucasian) managed from January 2002 to December 2012 in the Regional Vascular Centre at University Hospitals Coventry and Warwickshire NHS Trust, which serves a population of 950 000. CEA was undertaken in 474 (71%) patients for symptomatic carotid stenosis and in 196 (25%) asymptomatic patients during the same period. 74% of patients were hypertensive, 71% were smokers and 49% had hypercholesterolaemia.

Results

A high Pocock score (≥2.3%) was significantly associated with evidence of cerebral microemboli acutely following CEA (P=0.039, Mann-Whitney (MW) test). A Pocock score (≥2.3%) did not predict patients who required additional antiplatelet therapy (microemboli signal (MES) rate >50 hour^-1: P=0.164, MW test). Receiver operating characteristic analysis also showed that the Pocock score predicts acute postoperative microemboli (area under the curve (AUC) 0.546, 95% CI 0.502 to 0.590, P=0.039) but not a high rate of postoperative microemboli (MES >50 hour⁻¹: AUC 0.546, 95% CI 0.482 to 0.610, P=0.164). A Pocock score ≥2.3% showed a sensitivity of 74% for the presence of acute postoperative cerebral microemboli. A Pocock score ≥2.3% also showed a sensitivity of 77% and a negative predictive value of 90% for patients who developed a high microembolic rate >50 hour⁻¹ after carotid surgery.

Conclusion

These findings demonstrate that the Pocock score could be used as a clinical tool to identify patients at high risk of developing acute postoperative microemboli.

Right carotid-cutaneous fistula and right carotid pseudoaneurysm formation secondary to a chronically infected polyethylene terephthalate patch

Carotid endarterectomy (CEA) remains the treatment for significant carotid stenosis and stroke prevention. Approximately 100,000 CEAs are performed in the United States every year. Randomized trials have demonstrated an advantage of patch carotid angioplasty over primary closure. Complications from patches include thrombosis, transient ischemic attack, stroke, restenosis, pseudoaneurysm (PA), and infection. PA after CEA is rare, with a reported average of 0.37% of cases. We describe an unusual case of PA after polyethylene terephthalate (PTFE) patching for CEA. An 88-year-old female with Alzheimer's disease living in a nursing facility with a history of skin cancer on her right chest developed a new area of intermittent brisk bleeding on her right neck which was initially believed to be related to her skin cancer. She had a remote history of right CEA with a PTFE patch approximately a decade ago. A computed tomography angiograph-head-and-neck with showed a partially thrombosed PA in the region of her right common carotid artery bifurcation with a tract containing gas and fluid extending to the skin surface suspicious for a partially thrombosed, leaking PA. She was taken urgently to the operating room on broad-spectrum antibiotics where we performed a right neck exploration, ligation of a bleeding carotid PA by ligation of the right common, internal, and external carotid arteries, explantation of a chronically infected polyethylene terephthalate patch, and closure with a sternocleidomastoid advanced flap with multilayered closure. She was discharged to her nursing facility with 6 weeks of ceftriaxone intravenous (IV) and metronidazole IV through a peripherally inserted central catheter (PICC) line with no neurological sequelae.

Blood purine measurements as a rapid real-time indicator of reversible brain ischaemia

To preserve the disequilibrium between ATP and ADP necessary to drive cellular metabolism, enzymatic pathways rapidly convert ADP to adenosine and the downstream purines inosine and hypoxanthine. During ischaemia, these same pathways result in the production of purines. We performed a prospective observational study to test whether purine levels in arterial blood might correlate with brain ischaemia. We made real-time perioperative measurements, via microelectrode biosensors, of the purine levels in untreated arterial blood from 18 patients undergoing regional anaesthetic carotid endarterectomy. Pre-operatively, the median purine level was 2.4 μM (95% CI 1.3-4.0 μM); during the cross-clamp phase, the purines rose to 6.7 μM (95% CI 4.7-11.5 μM) and fell back to 1.9 μM (95% CI 1.4-2.7 μM) in recovery. Three patients became unconscious during carotid clamping, necessitating insertion of a temporary carotid shunt to restore cerebral blood flow. In these, the pre-operative median purine level was 5.4 μM (range 4.7-6.1 μM), on clamping, 9.6 μM (range 9.4-16.1 μM); during shunting, purines fell to below the pre-operative level (1.4 μM, range 0.4-2.9 μM) and in recovery 1.8 μM (range 1.8-2.6 μM). Our results suggest that blood purines may be a sensitive real-time and rapidly produced indicator of brain ischaemia, even when there is no accompanying neurological obtundation.

ABCD2 risk score does not predict the presence of cerebral microemboli in patients with hyper-acute symptomatic critical carotid artery stenosis

Introduction

ABCD² risk score and cerebral microemboli detected by transcranial Doppler (TCD) have been separately shown to the predict risk of recurrent acute stroke. We studied whether ABCD² risk score predicts cerebral microemboli in patients with hyper-acute symptomatic carotid artery stenosis.

Participants and methods

We studied 206 patients presenting within 2 weeks of transient ischaemic attack or minor stroke and found to have critical carotid artery stenosis (≥50%). 86 patients (age 70±1 (SEM: years), 58 men, 83 Caucasian) had evidence of microemboli; 72 (84%) of these underwent carotid endarterectomy (CEA). 120 patients (age 72±1 years, 91 men, 113 Caucasian) did not have microemboli detected; 102 (85%) of these underwent CEA. Data were analysed using X² and Mann–Whitney U tests and receiver operating characteristic (ROC) curves.

Results

140/206 (68%: 95% CI 61.63 to 74.37) patients with hyper-acute symptomatic critical carotid stenosis had an ABCD² risk score ≥4. There was no significant difference in the NICE red flag criterion for early assessment (ABCD² risk score ≥4) for patients with cerebral microemboli versus those without microemboli (59/86 vs 81/120 patients: OR 1.05 ABCD² risk score ≥4 (95% CI 0.58 to 1.90, p=0.867)). The ABCD² risk score was <4 in 27 of 86 (31%: 95% CI 21 to 41) embolising patients and in 39 of 120 (31%: 95% CI 23 to 39) without cerebral microemboli. After adjusting for pre-neurological event antiplatelet treatment (APT), area under the curve (AUC) of ROC for ABCD² risk score showed no prediction of cerebral microemboli (no pre-event APT, n=57: AUC 0.45 (95% CI 0.29 to 0.60, p=0.531); pre-event APT, n=147: AUC 0.51 (95% CI 0.42 to 0.60, p=0.804)).

Conclusions

The ABCD² score did not predict the presence of cerebral microemboli or carotid disease in over one-quarter of patients with symptomatic critical carotid artery stenosis. On the basis of NICE guidelines (refer early if ABCD² ≥4), assessment of high stroke risk based on ABCD² scoring may lead to inappropriate delay in urgent treatment in many patients.

Prospective validation study of transorbital Doppler ultrasound imaging for the detection of transient cerebral microemboli

BACKGROUND

Transient cerebral microemboli are independent biomarkers of early risk of ischaemic stroke in acute carotid syndromes. Transcranial Doppler imaging (TCD) through the temporal bone is the standard method for detection of cerebral microemboli, but an acoustic temporal bone window for TCD is not available in around one in seven patients. Transorbital Doppler imaging (TOD) has been used when TCD is not possible. The aim of this study was to validate the use of TOD against TCD for detecting cerebral microemboli.

METHODS

The study included patients undergoing elective carotid endarterectomy; all had confirmed temporal and orbital acoustic windows. Subjects gave written informed consent to postoperative TCD and TOD monitoring, which was performed simultaneously for 30 min by two vascular scientists.

RESULTS

The study included 100 patients (mean(s.e.m.) age 72(1) years; 65 men). Microemboli were detected by one or both methods in 40·0 per cent of patients: by TOD and TCD in 24 patients, by TOD alone in ten and by TCD alone in six. For detecting microemboli, TOD had a sensitivity of 80·0 per cent, specificity of 86·1 per cent, positive predictive value of 71·6 per cent and negative predictive value of 91·2 per cent. Bland-Altman analysis revealed no significant bias (bias 0·11 (95 per cent c.i. -0·52 to 0·74) microemboli; P = 0·810) with upper and lower limits of agreement of +6 and -6 microemboli.

CONCLUSION

TOD appears a valid alternative to TCD for detecting microembolic signals in patients with no suitable temporal acoustic window.