Perioperative cerebral perfusion in aortic arch surgery: a potential link with neurological outcome.

OBJECTIVES: The aim of this study was to examine whether perioperative changes in cerebral blood flow (CBF) relate to postoperative neurological deficits in patients undergoing aortic arch surgery involving antegrade selective cerebral perfusion (ASCP). METHODS: We retrospectively analysed data from patients who underwent aortic arch surgery involving ASCP and perioperative transcranial Doppler assessments. Linear mixed-model analyses were performed to examine perioperative changes in mean bilateral blood velocity in the middle cerebral arteries, reflecting changes in CBF, and their relation with neurological deficits, i.e. ischaemic stroke and/or delirium. Logistic regression analyses were performed to explore possible risk factors for postoperative neurological deficits. RESULTS: In our study population (N = 102), intraoperative blood velocities were lower compared to preoperative levels, and lowest during ASCP. Thirty-six (35%) patients with postoperative neurological deficits (ischaemic stroke, n = 9; delirium, n = 25; both, n = 2) had lower blood velocity during ASCP compared to patients without (25.4 vs 37.0 cm/s; P = 0.002). Logistic regression analyses revealed lower blood velocity during ASCP as an independent risk factor for postoperative neurological deficits (odds ratio = 0.959; 95% confidence interval: 0.923, 0.997; P = 0.037). CONCLUSIONS: Lower intraoperative CBF during ASCP seems independently related to postoperative neurological deficits in patients undergoing aortic arch surgery. Because CBF is a modifiable factor during ASCP, our observation has significant potential to improve clinical management and prevent neurological deficits.

Transcranial Doppler 24 Hours after Carotid Endarterectomy Accurately Identifies Patients Not at Risk of Cerebral Hyperperfusion Syndrome.

OBJECTIVES: Intra-operative transcranial Doppler (TCD) is the gold standard for prediction of cerebral hyperperfusion syndrome (CHS) in patients after carotid endarterectomy (CEA) under general anaesthesia. However, post-operative cerebral perfusion patterns may result in a shift in risk assessment for CHS. This is a study of the predictive value of additional post-operative TCD measurements for prediction of CHS after CEA. METHODS: This was a retrospective analysis of prospectively collected data in patients undergoing CEA with available intra- and post-operative TCD measurements between 2011 and 2016. The mean blood flow velocity in the middle cerebral artery (MCAVmean) was measured pre-operatively, intra-operatively, and post-operatively at two and 24 h. Intra-operative MCAVmean increase was compared with MCAVmean increase two and 24 h post-operatively in relation to CHS. Cerebral hyperperfusion (CH) was defined as MCAVmean increase ≥ 100%, and CHS as CH with the presence of headache or neurological symptoms. Positive (PPV) and negative predictive values (NPV) of TCD measurements were calculated to predict CHS. RESULTS: Of 257 CEA patients, 25 (9.7%) had CH intra-operatively, 45 (17.5%) 2 h post-operatively, and 34 (13.2%) 24 h post-operatively. Of nine patients (3.5%) who developed CHS, intra-operative CH was diagnosed in two and post-operative CH in eight (after 2 h [n = 5] or after 24 h [n = 6]). This resulted in a PPV of 8%, 11%, and 18%, and a NPV of 97%, 98%, and 99% for intra-operative, 2 h and 24 h post-operative TCD, respectively. CONCLUSIONS: TCD measurement of the MCAVmean 24 h after CEA under general anaesthesia is most accurate to identify patients who are not at risk of CHS.

A functional assessment of the circle of Willis before aortic arch surgery using transcranial Doppler.

BACKGROUND: Antegrade selective cerebral perfusion (ASCP) with systemic moderate hypothermia is routinely used as brain protection during aortic arch surgery. Whether ASCP should be delivered unilaterally (u-ASCP) or bilaterally (bi-ASCP) remains controversial. METHODS: We routinely studied the functional anatomy of the circle of Willis (CoW in all patients scheduled for arch surgery using transcranial color-coded Doppler over a decade. On the basis of these data, we classified observed functional variants as being "safe," "moderately safe," or "unsafe" for u-ASCP. RESULTS: From January 2005 to June 2015, 1119 patients underwent aortic arch surgery in our institution. Of these, 636 patients had elective surgery performed with ASCP. Preoperative full functional assessment of the CoW was possible in 61% of patients. A functionally complete CoW was found in only 27%. Of all variants, 72% were classified as being safe for u-ASCP, whereas 18% were moderately safe for u-ASCP, and 10% unsafe. Unsafe variants for bi-ASCP were observed in 0.5% of patients. CONCLUSIONS: The risk of ischemic brain damage due to malperfusion is estimated to be substantially higher during right u-ASCP than during bi-ASCP. Bi-ASCP is therefore highly preferable over u-ASCP if the function of the CoW is unknown. We propose a tailored approach using this full functional assessment preoperatively by applying u-ASCP via the right subclavian artery when considered safely possible, and bi-ASCP when considered a necessity to prevent cerebral malperfusion, and thus thereby try to reduce the embolic stroke risk of ostial instrumentation in bi-ASCP.

Long-term results of carotid stenting and risk factors in patients with severe carotid artery stenosis undergoing subsequent cardiac surgery.

AIMS: To identify risk factors for composite outcome of mortality, stroke or myocardial infarction in patients with severe carotid stenosis undergoing staged carotid artery stenting (CAS) with subsequent cardiac surgery. METHODS AND RESULTS: In this prospective observational study, we enrolled 643 consecutive patients with both symptomatic (i.e., with history of stroke) and asymptomatic severe carotid artery disease, who required cardiac surgery. Generally, cardiac surgery was planned 30 days after the CAS procedure. The composite outcome consisted of death, stroke and myocardial infarction. The composite outcome rate was 26.3% at 5 years and 47% at 8 years after CAS. Age ≥ 80 years (hazard ratio [HR] = 1.89; 95%CI, 1.18-3.03; P = 0.008), history of stroke (HR = 1.66, 1.16-2.37; P = 0.006), chronic obstructive pulmonary disease (HR = 1.86; 1.07-3.24; P = 0.03) and kidney disease (HR = 1.83, 1.11-3.04; P = 0.02) were independent risk factors for the composite outcome during long-term follow-up. CONCLUSIONS: In this study with staged CAS followed by cardiac surgery, we confirm previously reported event-free survival rates and identify several risk factors for the composite outcome. Future studies are needed to confirm the importance of the identified risk factors and to assess their predictive ability.

Surgical left subclavian artery revascularization for thoracic aortic stent grafting: a single-centre experience in 101 patients.

OBJECTIVES: To evaluate the indications, perioperative strategy and postoperative outcome of surgical left subclavian artery (LSA) revascularization combined with thoracic endovascular aortic repair (TEVAR) covering the LSA. METHODS: Between 2000 and 2017, a total of 101 consecutive patients underwent surgical revascularization of the LSA prior to, concomitant or following TEVAR. Revascularization was performed through a small supraclavicular incision and consisted of a transposition or bypass graft, using intraoperative transcranial Doppler monitoring. Data regarding indication, procedural details and postoperative results were retrospectively analysed. RESULTS: In total, 63 subclavian-carotid bypass grafts and 38 subclavian-carotid transpositions were performed in the context of TEVAR. The majority was performed prior to stent grafting to reduce the risk of stroke (n = 50), spinal cord ischaemia (n = 20), left arm malperfusion (n = 10) or to preserve a patent left internal mammary artery coronary bypass graft (n = 2). Secondary revascularization was performed in 14 patients, 2 times immediately due to acute left arm malperfusion and 12 times to treat invalidating left arm claudication. No in-hospital mortality and permanent spinal cord ischaemia occurred. Two (2%) ischaemic strokes were observed in patients with concomitant procedures, and none when separate, staged procedures were performed. Additional complications observed were permanent peripheral nerve palsies (9%), chyle leakage requiring diet (6%) and 1 bypass occlusion requiring a redo procedure. CONCLUSIONS: In patients predominantly selected upon the anticipated risk of (posterior) stroke, spinal cord ischaemia and left arm malperfusion, surgical revascularization of the LSA proved to be a safe treatment option to preserve antegrade LSA flow in the context of TEVAR.

Double-blind clinical trial of thalamic stimulation in patients with Tourette syndrome.

Deep brain stimulation of the thalamus has been proposed as a therapeutic option in patients with Tourette syndrome who are refractory to pharmacological and psychotherapeutic treatment. Patients with intractable Tourette syndrome were invited to take part in a double-blind randomized cross-over trial assessing the efficacy and safety of stimulation of the centromedian nucleus-substantia periventricularis-nucleus ventro-oralis internus crosspoint in the thalamus. After surgery, the patients were randomly assigned to 3 months stimulation followed by 3 months OFF stimulation (Group A) or vice versa (Group B). The cross-over period was followed by 6 months ON stimulation. Assessments were performed prior to surgery and at 3, 6 months and 1 year after surgery. The primary outcome was a change in tic severity as measured by the Yale Global Tic Severity Scale and the secondary outcome was a change in associated behavioural disorders and mood. Possible cognitive side effects were studied during stimulation ON at 1 year postoperatively. Interim analysis was performed on a sample of six male patients with only one patient randomized to Group B. Tic severity during ON stimulation was significantly lower than during OFF stimulation, with substantial improvement (37%) on the Yale Global Tic Severity Scale (mean 41.1 ± 5.4 versus 25.6 ± 12.8, P = 0.046). The effect of stimulation 1 year after surgery was sustained with significant improvement (49%) on the Yale Global Tic Severity Scale (mean 42.2 ± 3.1 versus 21.5 ± 11.1, P = 0.028) when compared with preoperative assessments. Secondary outcome measures did not show any effect at a group level, either between ON and OFF stimulation or between preoperative assessment and that at 1 year postoperatively. Cognitive re-assessment at 1 year after surgery showed that patients needed more time to complete the Stroop Colour Word Card test. This test measures selective attention and response inhibition. Serious adverse events included one small haemorrhage ventral to the tip of the electrode, one infection of the pulse generator, subjective gaze disturbances and reduction of energy levels in all patients. The present preliminary findings suggest that stimulation of the centromedian nucleus-substantia periventricularis-nucleus ventro-oralis internus crosspoint may reduce tic severity in refractory Tourette syndrome, but there is the risk of adverse effects related to oculomotor function and energy levels. Further randomized controlled trials on other targets are urgently needed since the search for the optimal one is still ongoing.