Effect of carotid revascularization on cerebral autoregulation in combined cardiac surgery†

Prevalence of carotid artery stenosis and intra-cranial lesions in patients with aortic arch aneurysm and its association with intraoperative regional cerebral oxygen saturation and postoperative neurological outcomes

Background

Although aortic aneurysm is associated with vascular aging and atherosclerosis, carotid and intracranial vascular disease prevalence in patients with aortic arch aneurysm remains unclear. Similarly, the effect of carotid and intracranial lesions on postoperative outcomes is unknown. This study aimed to investigate the prevalence of carotid artery stenosis and intracranial lesions in patients with aortic arch aneurysm and its association with intraoperative regional cerebral oxygen saturation (rScO2) and postoperative neurological outcomes, including delirium and cerebral infarction.

Methods

This retrospective observational study included 133 patients with true aortic arch aneurysm who underwent preoperative magnetic resonance imaging (MRI). We evaluated the prevalence of carotid and intracranial arterial lesions. Symptomatic cerebral infarction and delirium, defined by the confusion assessment method for the intensive care unit, were evaluated for their association with preoperative cerebrovascular lesions. Additionally, changes in regional saturation of the cerebral tissue at different surgical phases were evaluated for patients with and without cerebrovascular lesions.

Results

Fifteen (11.3%) patients experienced symptomatic cerebral infarction, and 64 (48.1%) had postoperative delirium. Preoperative MRI showed old infarction, microbleeds, significant carotid artery stenosis, and intracranial lesions in 21.1%, 14.3%, 10.5%, and 7.5% of the patients, respectively. White matter hyperintensities with Fazekas scale 2 were observed in 40.6% of the patients, while Fazekas scale 3 were observed in 18.8% of the patients. Preoperative MRI findings and postoperative neurological outcomes were not significantly different. Seventy-six patients underwent rScO2 monitoring intraoperatively. Changes in rScO2 in patients with and without carotid/cerebrovascular lesions were not significantly different. However, rScO2 was significantly lower in patients who developed cerebral infarction.

Conclusions

Significant carotid artery stenosis and intracranial lesions were observed in 10.5% and 7.5% of the patients, respectively. Although preoperative MRI findings and changes in rScO2 or postoperative outcomes showed no significant association, patients with postoperative cerebral infarction showed significantly lower rScO2 intraoperatively.

Alveolar Recruitment Maneuver Reduces Cerebral Oxygen Saturation and Cerebral Blood Flow Velocity in Patients During Carotid Endarterectomy

BACKGROUND This study aimed to determine the effects of alveolar recruitment maneuver (RM) on cerebral oxygen saturation and cerebral blood velocity in patients undergoing carotid endarterectomy (CEA) before clamping of the carotid artery. MATERIAL AND METHODS In this crossover exploratory study, all patients were randomized to undergo an RM (30 cmH₂O of continuous airway pressure for 30 s) and a "sham" maneuver (SM; 5 cmH₂O for 30 s), followed by an alternative intervention after a 5-min equilibration period. Near-infrared spectroscopy (NIRS) was used to monitor regional cerebral oxygen saturation (rSO₂), and transcranial Doppler ultrasonography (TCD) to evaluate blood velocity of the middle cerebral artery (V-MCA). Changes in rSO₂, V-MCA, mean arterial pressure (MAP), and heart rate (HR) in response to the 2 interventions were compared. RESULTS A total of 59 patients underwent the study procedure. RM reduced rSO₂, V-MCA, MAP, and HR, but these variables slightly changed during SM. A significant drop in rSO₂ was observed immediately after RM compared with the baseline value (68.51±4.4% vs 64.12±5.15%; P<0.001). The decrease in rSO₂ was higher during the RM than during the SM (-6±4% vs 1±2%; P<0.001). Similarly, change in V-MCA was more significant in response to RM than SM (-26±19% vs 19±16%; P<0.001). The V-MCA value changed from 39 cm/s to 29 cm/s after RM. In addition, V-MCA of the ipsilateral to the surgical side decreased more obviously than the contralateral side (-26±19% vs -20±17%; P=0.001). CONCLUSIONS An RM at 30 cmH₂O of continuous airway pressure for 30 s decreased rSO₂ and V-MCA. In addition, MAP and HR were affected.

[In-hospital outcomes of transcutaneous coronary intervention and carotid endarterectomy in hybrid and staged regimens]

The aim of this study was comparative assessment of in-hospital outcomes after hybrid and staged surgical management of patients presenting with haemodynamically significant lesions of the coronary (CA) and brachiocephalic arteries (BCA) treated by means of either endovascular or surgical techniques. Over the period from 2010 to 2017, we operated on a total of 197 patients with stenotic lesions of the carotid and coronary arteries. The strategy of revascularization included transcutaneous coronary intervention (TCI) and carotid endarterectomy (CEA). Of these, 73 (37%) patients underwent staged revascularization of the brain and myocardium in various sequence (TCI-CEA or CEA-TCI), with a mean interval between the operations amounting to 9.89±7.36 months. Unfavourable outcomes were regarded as the development of such significant cardiovascular events as myocardial infarction (MI), acute impairment of cerebral circulation, death, repeat unplanned revascularization. For hybrid strategy (TCI+CEA) the index period of assessing the outcomes was the single in-hospital period, whereas for the staged strategy it was the time period beginning from the in-hospital period of the primary operation and ending by the in-hospital period of the second stage. The groups were comparable by the absolute majority of the parameters. More than half of the patients were elderly males. One third had a history of MI. The findings of coronary angiography most often revealed lesions of 1-2 CAs. The average parameters of carotid artery stenosis, according to the BCA angiography varied from 74.9 to 82.6%, with bilateral occlusive stenotic lesions being revealed in every third patient. In connection with more frequent involvement of 1-2 CAs the patients underwent implantation of 1-2 stents. In our sample we used a total of 247 stents. Of these, 119 were uncoated and 128 were drug-eluting stents. No between-group significant differences in the development of unfavourable cardiovascular events during the in-hospital postoperative period were revealed. However, despite this, a pronounced negative tendency of the complication rate was noted in the group of staged revascularization. Non-optimal time intervals between the stages of the operations in a third of cases exceeded one year on the patient's own initiative. Nearly a quarter of patients did not come for the second stage of revascularization. An important finding of our study was no increase in the risk of stent thrombosis in hybrid operations compared with the staged approach, despite administration of a loading dose of clopidogrel after CEA, but not before TCI. Another significant result was the fact of greater availability of revascularization of the myocardium and the brain within the framework of the hybrid strategy as compared with the staged one, which may play an important role in prevention of ischaemic unfavourable events in the remote period of follow up.