Maintaining carotid flow by shunting during carotid endarterectomy diminishes the inflammatory response mediating ischaemic brain injury

Level of plasma catecholamine predicts surgical outcomes of carotid body tumors: Retrospective cohort study

BACKGROUNDS

Carotid body tumors (CBTs) are rare neoplasms and some of them produce catecholamine. Although operations for catecholamine-producing CBTs are safe, the relationship between prognosis and endocrine function has not been analyzed before.

METHODS

Patients diagnosed with CBTs in our department between 2009 and 2018 were analyzed. Plasma catecholamine was examined as a variable of surgical outcomes and prognosis by using statistical methods.

RESULTS

Patients who suffered CBTs and underwent operations were divided into two groups according to their plasma catecholamine. Patients in the normal group had more or heavier surgical complications, such as neurological complications (P = .008) and blood loss (P = .03), than those in the high group. However, overall survival, local recurrence, and remote metastasis were not varied significantly in both groups.

CONCLUSIONS

A high level of plasma catecholamine was a predictor for the improved operative outcomes of CBTs. Hence, nonfunctional CBTs had further short-term surgical complications.

Copeptin Levels Do Not Correlate With Cross-Clamping Time in Patients Undergoing Carotid Endarterectomy Under General Anesthesia

Copeptin is a sensitive and more stable surrogate marker for arginine vasopressin. In this study, we evaluated copeptin levels in carotid endarterectomy (CEA) patients, perioperatively, to determine whether copeptin levels can be related to carotid artery cross clamping (CC) time and to postoperative neurological outcomes. Copeptin, interleukin 6, C-reactive protein, cortisol, and brain natriuretic peptide were measured preoperatively (T1) and 3 hours postoperatively (T3) as well as intraoperatively (T2). We recruited 77 patients. Values of copeptin rose gradually over the observed times: T1 = 7.9 (6.4-9.6), T2 = 12.6 (9.3-16.8), and T3 = 72.3 (49.1-111.2) pmol/L. There was a significant difference for repeated measurement ( P = .000, P = .000, and P = .000). Duration of carotid artery CC during CEA does not affect postoperative copeptin level (CC ≤ 13 minutes: 106.8 ± 93.6 pmol/L, CC > 13 minutes: 96.7 ± 89.1 pmol/L; P = .634). Preoperative copeptin level was significantly higher in patients with ulcerated plaque morphology. Activation of the stress axis in patients undergoing CEA results in copeptin elevation. Duration of CC during CEA does not affect postoperative copeptin levels.

Oxidative Stress and Total Antioxidant Status During Internal Carotid Artery Clamping with or without Shunting: An Experimental Pilot Study

Background

The exact role of shunting during carotid endarterectomy remains controversial and unclear. The aim of this experimental study was to investigate to what degree carotid clamping may induce changes in the cerebral oxidative status and to focus on the relation of these changes with shunt insertion.

Material/Methods

Forty New-Zealand rabbits were randomized into 4 groups: group 1 classifying animals with carotid shunt and patent contralateral carotid artery; group 2 shunt and occlusion of the contralateral carotid artery; group 3 no-shunt and patent contralateral carotid artery; and group 4 no-shunt and occlusion of the contralateral carotid artery. Blood samples were collected from the ipsilateral internal jugular vein, immediately after carotid clamping (time 0), and then at 5, 10, 15, 30, and 60 minutes afterwards. Evaluation of oxidative stress was accomplished by measuring the lag-time, representing the initial phase of oxidation, rate of accumulation (RA), showing concentration of free oxygen radical and total antioxidant status (TAS) representing antioxidant composition of serum.

Results

Lag-time was significantly different in time points 0, 30 and 60 minutes within each different group. TAS was significantly different in time points 0, 15 and 60 min and RA in time points 0, 5, 10 and 60 min within each different group. 60 minutes after carotid clamping, the rate of accumulation as well as lag-time and TAS were increased in all groups, independently of using or not shunting or the presence of contralateral occlusion. After comparing groups 1, 2 and 3 regarding lag-time, TAS and RA, we did not find statistical difference among the groups at any time point. On the contrary, groups 1, 2 and 3 did show significantly different values comparing to group 4 after 60 min of occlusion.

Conclusions

Our experimental work based on cerebral metabolism found a significantly higher oxidative stress in models with contralateral carotid occlusion. The use of shunt in all other models did not have any influence on oxidative response. Future human studies should focus on the relation of oxidative status and shunt insertion to determine the benefit of selective or routine shunting during CEA.

PGE2 suppresses NK activity in vivo directly and through adrenal hormones: effects that cannot be reflected by ex vivo assessment of NK cytotoxicity

Surgery can suppress in vivo levels of NK cell cytotoxicity (NKCC) through various mechanisms, including catecholamine-, glucocorticoid (CORT)-, and prostaglandin (PG)-mediated responses. However, PGs are synthesized locally following tissue damage, driving proinflammatory and CORT responses, while their systemic levels are often unaffected. Thus, we herein studied the role of adrenal factors in mediating in vivo effects of PGs on NKCC, using adrenalectomized and sham-operated F344 rats subjected to surgery or PGE(2) administration. In vivo and ex vivo approaches were employed, based on intravenous administration of the NK-sensitive MADB106 tumor line, and based on ex vivo assessment of YAC-1 and MADB106 target-line lysis. Additionally, in vitro studies assessed the kinetics of the impact of epinephrine, CORT, and PGE(2) on NKCC. The results indicated that suppression of NKCC by epinephrine and PGE(2) are short lasting, and cannot be evident when these compounds are removed from the in vitro assay milieu, or in the context of ex vivo assessment of NKCC. In contrast, the effects of CORT are long-lasting and are reflected in both conditions even after its removal. Marginating-pulmonary NKCC was less susceptible to suppression than circulating NKCC, when tested against the xenogeneic YAC-1 target line, but not against the syngeneic MADB106 line, which seems to involve different cytotoxicity mechanisms. Overall, these findings indicate that elevated systemic PG levels can directly suppress NKCC in vivo, but following laparotomy adrenal hormones mediate most of the effects of endogenously-released PGs. Additionally, the ex vivo approach seems limited in reflecting the short-lasting NK-suppressive effects of catecholamines and PGs.

Subtle Cerebral Damage after Shunting vs Non Shunting during Carotid Endarterectomy

OBJECTIVE

To compare the extent of subtle cerebral damage (SCD) in patients undergoing carotid endarterectomy with or without shunt placement.

DESIGN

Prospective, randomised study.

PATIENTS AND METHODS

We assessed a consecutive series of 96 patients undergoing endarterectomy for severe unilateral left carotid stenosis who had been randomly assigned to receive a shunt (48) or not (48). Eligibility criteria included age up to 80 years and Mini-Mental State Examination score >24 points. Patients underwent neuropsychological testing before surgery. Serum concentrations of S100 protein, neuron-specific enolase (NSE) and interleukin-6 (IL-6) were measured intraoperatively before and after carotid clamping. Finally, each patient underwent neuropsychological testing 3 weeks after surgery.

RESULTS

Patients with and without shunt had similar serum concentrations of S100 protein, NSE and IL-6 as well as similar neuropsychological test scores, all p>0.05.

CONCLUSIONS

There was no difference in subtle cerebral damage between patients randomized to receive a shunt or not.

Increased incidence of cerebral clamping ischemia during early contralateral carotid endarterectomy

OBJECTIVES

The aim of our study was to assess the influence of previous contralateral carotid endarterectomy (CEA) and of the timing of the procedures on cerebral clamping ischemia during the second operation in patients undergoing staged bilateral CEA.

METHODS

We reviewed the 251 patients who presented with bilateral carotid stenosis of > or =70% at the time of the first admission and underwent staged bilateral CEA between January 2001 and December 2004. Surgery was performed under locoregional anesthesia. Cerebral perfusion was monitored with mental status and contralateral motor function evaluation in awake patients. Selective carotid shunting was performed for patients who manifested neurologic deficits. Univariate and multivariate analyses were performed for the variables of interest.

RESULTS

Twenty-two patients (8.8%) required carotid shunting during the first procedure and 28 (11.1%) during the second one. Nine of the latter also had shunts during the first CEA, whereas 19 tolerated cross-clamping during the first operation. Among the patients who underwent contralateral CEA < or =30 days, 23 of 146 required carotid shunting; between 31 and 60 days, 4 of 73; and after 61 days, 1 of 32 (P = .023; univariate analysis). The chi2 for trend was statistically significant (P = .009). Patients operated on the second side < or =30 days had a nearly fourfold risk of shunting during the second procedure compared with patients operated on > or =31 days. The highest risk was observed in patients with a shunt during the first operation who underwent the second CEA < or =30 days. Multivariate analysis also identified the time intervals between CEAs and the need of shunting during the first procedure as independent risk factors (P = .042 and P < .001).

CONCLUSIONS

These data show an increased incidence of cerebral clamping ischemia during contralateral endarterectomy performed < or =30 days; whereas after longer intervals between CEAs, the need for shunting is significantly reduced.

Perioperative stress response to carotid endarterectomy: The impact of anesthetic modality

OBJECTIVE

Surgery for extracranial carotid artery disease has been challenged by carotid angioplasty stenting because the latter is less invasive and avoids surgical trauma. In fact, the magnitude of the perioperative stress response evoked by carotid endarterectomy (CEA) has never been evaluated. Our aim was to determine the degree of surgical trauma caused by CEA and to define differences related to the use of locoregional or general anesthesia.

METHODS

We prospectively studied 113 consecutive CEAs performed on 109 patients admitted at a community institutional center. Patients were stratified for demographics and risk factors and operated on under locoregional (LA) or general anesthesia (GA) depending on both the surgeon preference and patient's compliance. Selective carotid shunting was performed for patients who manifested neurologic deficits under LA or had stump pressure values </=30 mm Hg under GA. Markers of the stress response, including cortisol, adrenocorticotropic hormone, prolactin, and C-reactive protein, were measured intraoperatively, before and after carotid artery cross-clamping (CACC), and postoperatively up to the third day after surgery. Hemodynamic variability was assessed during surgery and for 24 hours postoperatively. Operative times were also measured. Surgeons were considered as independent variables for stress response. Statistics were run by means of nonparametric tests and univariate and multivariate analysis with a linear regression model.

RESULTS

CEA was performed under GA in 63 cases (55.8%) and under LA in 50 (44.2%). The two groups were comparable in terms of demographics and risk factors. Intraoperatively, cortisol and adrenocorticotropic hormone levels were significantly higher in the LA group (both P <.001). CACC increased the intraoperative cortisol levels in both the GA (P =.019) and the LA groups (P =.006). However, in patients who underwent carotid shunting, this effect was abolished (GA group, P =.779; LA group, P = 1.0). During the early postoperative period there was no difference between the two groups. On postoperative day 1 the stress response was abolished in both groups. Prolactin levels increased intraoperatively in both the LA and GA groups and returned within preoperative values on postoperative day 1. Prolactin levels were higher in the GA group (P =.003 intraoperatively and P <.001 postoperatively). C-reactive protein significantly increased in both GA and LA groups on postoperative days 1 and 2 and started to decrease on day 3 with no differences between the two groups at any time. Hemodynamic variability and considered risk factors including individual surgeon were not significant variables. Gender-related differences were found only in prolactin secretion. The length of surgery had an impact for procedures that lasted >120 minutes. Three patients experienced an intraoperative neurologic event and had higher post-CACC cortisol values as compared to asymptomatic patients.

CONCLUSIONS

Intraoperative surgical stress was higher under LA and was blunted by carotid shunting under both LA and GA. Within 2 hours after surgery the anesthetic modality no longer had any impact on surgical trauma. The stress response to CEA, regardless of the type of anesthesia, was abolished within 24 hours. Intraoperative stress response, namely hypercortisolemia, directly correlated with subclinical and clinical cerebral hypoperfusion/ischemia during CACC. Hence, attenuation of the stress response to CEA might decrease the incidence of cerebral ischemic events.

Potential prophylactic measures against postoperative immunosuppression: could they reduce recurrence rates in oncological patients?

BACKGROUND

Removing the primary tumor is indispensable for eliminating the major pool of metastasizing cells, but the surgical procedure itself is suspected of promoting metastases. This adverse effect is attributed to several mechanisms acting in synergy, including mechanical release of tumor cells, enhanced angiogenesis, secretion of growth factors, and immunosuppression. Here we provide new insights into mechanisms of postoperative immunosuppression and assess the assumptions underlying the hypothesis that, by suppressing cell-mediated immunity (CMI), surgery may render the patient vulnerable to metastases that otherwise could have been controlled.

METHODS

An extensive review of relevant articles in English identified by using the MEDLINE database and cross-referencing.

RESULTS

Current literature suggests that (1) CMI can control minimal residual disease, especially if surgery is performed early; (2) major surgery transiently but markedly suppresses CMI through multiple mechanisms now better understood; (3) surgical stress promotes experimental metastasis through immunosuppression, but the clinical evidence remains indirect because of ethical limitations.

CONCLUSIONS

Minimizing postoperative immunosuppression seems feasible, may limit recurrence, and should be introduced into the broader array of considerations when planning oncological surgeries. In the short run, physicians could try to avoid immunosuppressive anesthetic approaches, inadvertent hypothermia, excessive blood transfusions, and untended postoperative pain. When feasible, minimally invasive surgery should be considered. In the long run, clinical trials should evaluate prophylactic measures, including perioperative immunostimulation and several antagonists to cytokines and hormones specified herein.

Prostaglandin e(2) suppresses NK activity in vivo and promotes postoperative tumor metastasis in rats

BACKGROUND

Prostaglandins (PGs) were shown in vitro to suppress several functions of cellular immunity. It is unclear, however, whether physiological levels of PGs can suppress cellular immunity in vivo and whether such suppression would compromise postoperative host resistance to metastasis.

METHODS

Fischer 344 rats were administered PGE(2) in doses (18 to 300 micro g/kg subcutaneously) that increased the serum levels approximately 2- to 4-fold. We then assessed the number and activity of circulating natural killer (NK) cells, as well as rats' resistance to experimental metastasis of a syngeneic NK-sensitive tumor (MADB106). To study whether endogenously released PGs after surgery compromise these indices, we tested whether laparotomy adversely affects them and whether a cyclooxygenase-synthesis inhibitor, indomethacin (4 mg/kg), attenuates these effects.

RESULTS

PGE(2) dose-dependently suppressed NK activity per NK cell and dose-dependently increased 4- and 24-hour MADB106 lung tumor retention (LTR); 240 micro g/kg of PGE(2) quadrupled the number of lung metastases counted 3 weeks later. Selective depletion of NK cells abrogated the promotion of LTR by PGE(2). Surgery significantly suppressed NK activity and increased MADB106 LTR, and indomethacin halved these effects without affecting nonoperated rats.

CONCLUSIONS

PGE(2) is a potent in vivo suppressor of NK activity, and its postoperative release may promote tumor recurrence.

Serum S100B protein levels are correlated with subclinical neurocognitive declines after carotid endarterectomy

OBJECTIVE

Carotid endarterectomy (CEA) is an effective means of stroke prevention among appropriately selected patients; however, neuropsychometric testing has revealed subtle cognitive injuries in the early postoperative period. The purpose of this study was to establish whether serum levels of two biochemical markers of cerebral injury were correlated with postoperative declines in neuropsychometric test performance after CEA.

METHODS

Fifty-five consecutive patients underwent a battery of neuropsychometric tests 24 hours before and 24 hours after elective CEA. Two patients were excluded because of postoperative strokes. The pre- and postoperative serum levels of S100B protein and neuron-specific enolase for injured patients, defined as those who exhibited significant declines in neuropsychometric test performance (n = 12), were compared with the levels for uninjured patients (n = 41).

RESULTS

There were no significant differences in the baseline S100B levels for the two groups. Injured patients exhibited significantly higher S100B levels, compared with uninjured patients, at 24, 48, and 72 hours after surgery (P < 0.05). There were no significant differences in neuron-specific enolase levels for injured and uninjured patients at any time point.

CONCLUSION

These data suggest that subtle cerebral injuries after CEA, even in the absence of overt strokes, are associated with significant increases in serum S100B but not neuron-specific enolase levels. Analyses of earlier time points in future studies of subtle cognitive injuries and biochemical markers of cerebral injury after CEA may be revealing.

Causes of perioperative stroke after carotid endarterectomy: special considerations in symptomatic patients

In order to maximize the efficacy of carotid endarterectomy (CEA), the rate of perioperative stroke must be kept to a minimum. A recent analysis of carotid surgery at our institution found that most perioperative strokes were due to technical errors resulting in thrombosis or embolization. From 1992 through 1997 we have performed nearly 1200 additional CEAs; the purpose of this study was to examine recent trends in the causes of perioperative stroke, with specific attention to differences in symptomatic and asymptomatic patients. The records of 1041 patients undergoing 1165 CEAs were reviewed from a prospectively compiled database. Analysis of these data showed that a history of preoperative stroke appears to increase the risk of perioperative stroke after CEA. Surgical factors associated with perioperative stroke include an inability to tolerate clamping, use of an intraarterial shunt, and having surgery performed under general anesthesia; these factors are clearly interrelated and only the use of intraarterial shunting remains a risk factor by multivariate analysis. Over half of all perioperative strokes (54%) appear to be caused by intraoperative or postoperative thrombosis and embolization. The patient requiring use of intraarterial shunting and/or with a preoperative stroke most likely has a significant watershed area of brain at increased risk of infarction. However, technical errors are still the most common cause of perioperative stroke in these high-risk patients. Such high-risk patients may manifest clinical stroke from small emboli that may be tolerated by asymptomatic clamp-tolerant patients. Technical precision and appropriate cerebral protection are particularly critical for successful outcomes in high-risk patients.