Outcome of Near-Infrared Spectroscopy-Guided Selective Shunting During Carotid Endarterectomy in General Anesthesia.

BACKGROUND: To analyze the outcome of near-infrared spectroscopy (NIRS)-guided selective shunting during carotid endarterectomy and the procedural outcome. METHODS: In this retrospective single-center study, patients undergoing carotid endarterectomy in general anesthesia and receiving bihemispheric NIRS as single neuromonitoring tool between January 2009 and January 2014 were included. Shunting was applied if the reduction in the NIRS values after cross-clamping on the ipsilateral side exceeded 15%. Patients with contralateral occlusion of the internal carotid artery (ICA) were excluded, as were patients operated on by surgeons performing routine shunting. All patients underwent intraoperative angiography after vessel recanalization. RESULTS: NIRS trend was available in 441 patients. Twenty-eight were excluded from this study (14 due to preference for general shunting, 13 due to contralateral ICA occlusion, and 1 due to intraoperative ICA occlusion), resulting in a final sample of 413 patients. We observed a >15% drop in NIRS values on the ipsilateral side in 29 (7%) patients. Accordingly, an intraluminal shunt was placed into the ICA. Shunting was not performed in 384 patients (<15% drop in NIRS values). Interestingly, the NIRS values on the contralateral side were significantly elevated after cross-clamping compared with baseline in the group without shunt (P < 0.0001). On the contrary, patients requiring an ICA shunt revealed a statistically significant reduction in the rSO2 on the contralateral side compared with the baseline (after ipsilateral clamping) (P = 0.047). Three patients overall suffered a stroke, all of whom were in the no-shunt group (combined stroke rate of 0.8% [3/384] with no significant intergroup difference). There was no difference in morbidity factors between the two groups. However, surgical revision after intraoperative angiography was significantly more frequent in the shunt group (17.2%, 5/29) versus the no-shunt group (6%, 23/384), (P < 0.037). CONCLUSIONS: An NIRS-guided selective shunting strategy was associated with excellent clinical outcomes and has the potential to identify patients at risk for hypoperfusion during the clamping period. However, a potentially shunt-associated higher rate of requiring local revisions (due to flaps, twisting, stenosis, and kinking) in ICA was observed. Additional studies are needed to further refine cut-off values for NIRS, indicating the need for shunting.

Routine versus selective near-infrared spectroscopy-guided shunting during carotid eversion endarterectomy.

OBJECTIVES: The aim of this study was to compare outcomes of routine shunting to near-infrared spectroscopy (NIRS)-guided shunting in patients undergoing eversion endarterectomy (EEA) under general anaesthesia. METHODS: We retrospectively evaluated data of all patients undergoing EEA of the internal carotid artery (ICA) in our department from January 2011 until January 2019. Included were patients with EEA of the ICA and the patients were divided into 2 groups: selective-shunting group and routine-shunting group. Patients (i) with patch angioplasty during the surgery, (ii) undergoing surgery for restenosis and (ii) stenosis after radiation therapy, (iii) without recorded regional cerebral oxygen saturation trends, (iv) presenting with an emergency treatment indication and (v) operated upon by residents were excluded. In all patients, EEA was performed in general anaesthesia and under NIRS monitoring. One-to-one propensity score matching was used to compare EEA outcomes after routine shunting to NIRS-guided shunting. Primary end points were defined as perioperative stroke and in-hospital mortality after EEA. RESULTS: Routine and NIRS-guided selective shunting were applied in 340 (34.0%) and 661 (66.0%) patients, respectively. A total of 277 pairs were generated via propensity score matching. Fifty-eight (20.1%) from the selective-shunting group were intraoperatively shunted. Concomitant procedures were more frequently performed in the routine-shunting group [170 (61.4%) vs 47 (17.0%), 180 (65%) vs 101 (36.5%), and 60 (21.7%) vs 6 (2.2%), P < 0.001]. The perioperative stroke rate in the routine-shunting group was higher as well [11 (4.0%) vs 3 (1.1%), P = 0.022]. In-hospital death was overall 0.2% (n = 1). Multivariable logistic regression in the matched patient indicated age (odds ratio 1.050, 95% confidence interval 1.002-1.104, P = 0.046) and routine shunting (odds ratio 2.788, confidence interval 1.119-7.428, P = 0.032) as risk factors for perioperative stroke during EEA of the ICA. CONCLUSIONS: We found that, during EEA of the ICA, under general anaesthesia, NIRS-guided selective shunting was associated with a lower incidence of perioperative stroke than routine shunting.

Carotid intima-media thickness and distensibility measured by MRI at 3 T versus high-resolution ultrasound.

We evaluated an MRI protocol at 3 T for the assessment of morphological and functional properties of the common carotid artery (CCA) in 32 healthy volunteers and 20 patients with high-grade internal carotid artery stenosis. Wall thickness of the CCA was measured by using multislice 2D T2 dark blood fast spin echo sequences and compared with intima-media thickness (IMT) determined by ultrasound. Carotid distensibility coefficient (DC) quantified by blood pressure and CCA diameter change during the cardiac cycle was measured by ECG gated 3D T1 CINE MRI and M-mode ultrasound. Apart from generally higher values in MRI high agreement was found for wall thickness and compliance in volunteers and patients. Remaining differences between both methods may be attributed to slightly different methods for measuring IMT and DC. Our findings indicate that MRI at 3 T is a feasible and promising tool for the comprehensive assessment of normal carotid geometry and function.

Aortic valve annuloplasty: new single suture technique.

Reconstruction strategies for aortic valve insufficiency in the presence of aortic annulus dilatation are usually surgically challenging. We demonstrate a simple, modified Taylor technique of downsizing and stabilization of the aortic annulus using a single internal base suture. Since April 2011, 22 consecutive patients have undergone safe aortic valve annuloplasty. No reoperations for aortic valve insufficiency and no deaths occurred.

An approach towards molecular imaging of activated platelets allows imaging of symptomatic human carotid plaques in a new model of a tissue flow chamber.

The development of magnetic resonance imaging (MRI) contrast agents targeting epitopes in atherosclerosis is of general interest. In particular, early detection of activated platelets as key players in plaque rupture could provide improved triage of patients. However, so far the efficiency of contrast agents targeting human pathologies can only be examined in animal experiments, which do not necessarily reflect human in vivo conditions. We therefore describe application of a contrast agent targeting activated human platelets in an MRI tissue flow chamber, allowing detection and characterization of contrast agent binding. Microparticles of iron oxide (MPIO) were conjugated to an antibody targeting ligand-induced binding sites (LIBS) on the activated platelet glycoprotein IIb/IIIa-receptor or to control antibody, resulting in LIBS-MPIO or control-MPIO contrast agent. Human endarterectomy specimens from patients with acute stroke or transient ischemic attack were imaged ex vivo before and after contrast agent perfusion using a 9.4 T MRI system. Specimens were measured under static (n = 18) or flow conditions (n = 18) in a specially designed flow chamber setup, simulating physiological conditions in a stenosed vessel. A significant MPIO-induced negative contrast was achieved in MRI by LIBS-MPIO in specimens under static and flow conditions (LIBS-MPIO vs control-MPIO: p < 0.01), and the location of LIBS-MPIO binding corresponded well between histology and MRI (p < 0.05). The number of MPIOs per platelet area on endarterectomy specimens in histology was significantly higher with LIBS-MPIO (p < 0.001). Furthermore, the intensity of contrast agent binding and signal change showed the potential to reflect the severity of clinical symptoms. LIBS-MPIO allows the detection of activated platelets on the surface of symptomatic atherosclerotic human plaques using molecular MRI. Furthermore, the MRI tissue flow chamber setup described could help to evaluate binding properties of contrast agents, and might therefore be an interesting tool for contrast agent development from animal experiments towards clinical application.