Event Of Occlusion Research Articles

It's time to stop using nitrous oxide for pediatric mask induction.

Mask induction of anesthesia for pediatric patients has included the use of nitrous oxide since the inception of pediatric anesthesia. However, the use of nitrous oxide precludes adequate preoxygenation. Additionally, pediatric physiology (less Functional Residual Capacity, higher oxygen consumption), increased risk of laryngospasm and lack of intravenous access increase the risk of a severe airway complication in the event of airway occlusion. Nitrous oxide does not facilitate tranquil mask placement on an unwilling child and does not meaningfully speed mask induction. Exposure to nitrous oxide has potential occupational health concerns and nitrous oxide has significant environmental detriment. Utilizing other, evidence-based, techniques to facilitate tranquil mask placement will assure that patients have a pleasant induction experience and avoiding nitrous oxide will reduce the environmental impact, as well as improve the safety of, pediatric mask induction.

Modified Allen Test Assessment via Imaging Photoplethysmography

Abstract The modified Allen test (MAT) is a widely used tool to examine the perfusion capacities of the arteries (ulnar or radial) of the hand. In clinical practice, MAT is utilized to ensure that in the event of occlusion, remaining vessels guarantee sufficient hand perfusion. This work shows that perfusion assessment via imaging photoplethysmography (iPPG) can be used to assess MAT. We captured the hands of seven subjects with a standard RGB camera while performing a MAT. Out of these captured video recordings, the iPPG signal was extracted via plane-orthogonal-to-skin transformation. Based on these extracted signals, we derive the heart rate, signal-to-noise ratio, DC parameter, and correlation with a reference iPPG signal to determine if an Allen test was pathological or inconspicuous. For all seven subjects, the results of our MAT assessment were identical to the medical expert’s assessment. This paper presents a procedure and initial thresholds for objectively evaluating and quantifying MAT.We show how globally and locally calculated parameters can be used to assess the perfusion of the investigated hand. This analysis makes it possible to quantify the exact point in time when the perfusion is again sufficient. If a reperfusion problem occurs, we are able to localize the spatial regions of occurrence. The presented hardware setup is affordable and can be easily installed and used in every doctor’s office.

10 clinical tips for advancing patient safety when using syringe pump systems for microinfusion intravenous drug therapy.

10 clinical tips for advancing patient safety when using syringe pump systems for microinfusion intravenous drug therapy.

Association of pre-mechanical thrombectomy collateral scores with functional outcomes in the early versus extended window for thrombectomy.

Introduction: Cerebral collateral circulation refers to the anastomoses that reroute the blood flow to the ischemic penumbra in the event of a large vessel occlusion (LVO). We aim to determine the utility of pre-mechanical-thrombectomy (MT) collateral scores in the early (<6 h from onset) versus extended (6-24 h from onset) window for MT with respect to a 3-month functional outcome, 3-month mortality, and early neurological improvement. Methods: We performed a retrospective chart review of patients who underwent MT for an anterior circulation LVO at a comprehensive stroke center from 7/2014 to 12/2020. A board-certified neuroradiologist, who was blinded to the clinical outcomes, used the collateral grading scales of Miteff (ordinal), Maas (ordinal), and modified-Tan (dichotomous) to designate collateral scores on the pre-MT CT Angiogram. The patients were divided into early (<6 h from onset) versus extended (6-24 h from onset) window groups depending on their timing of presentation to the emergency department. A regression analysis was performed, controlling for the baseline parameters, with the pre-MT collateral grading scores as predictors. The outcome measures were a good functional outcome (3-month mRS 0-2), mortality, and early neurological improvement. Results: A total of 220 patients met the inclusion criteria. In the overall cohort, the pre-MT scale of Maas was associated with a good functional outcome (OR, 0.58; 95% CI, 0.34-0.99; P 0.047) and mortality (OR, 0.55; 95% CI, 0.31-0.97; P 0.036). For the 162 patients who presented in the early window for MT, all of three pre-MT scales of Maas (OR, 0.39; 95% CI, 0.2-0.77; P 0.006), Miteff (OR, 0.43; 95% CI, 0.19-0.97; P 0.042) and modified-Tan (OR, 5.62; 95% CI, 1.16-27.37; P 0.033) were associated with a good functional outcome, whereas the Maas (OR, 0.48; 95% CI, 0.26-0.9; P 0.021) and the Miteff scale (OR, 0.4; 95% CI, 0.22-0.74; P 0.003) were associated with mortality. For the 58 patients who presented in the extended window for MT, none of the collateral grades were associated with functional outcome, mortality, or early neurological improvement. Conclusions: Our study demonstrates that while several collateral grades are helpful to predict outcomes in patients presenting in the early window, none of the pre-MT collateral scores were associated with outcomes in patients who presented in the extended window for MT. Thus, the current strategy of using perfusion imaging for the selection of patients for MT in the extended window should continue.

Role of collateral circulation in maintaining and restoring the left ventricular function and modern methods for its assessment

The coronary blood flow plays an important role in protecting the myocardium from ischemia and maintaining the cardiomyocyte function in the event of occlusion of one of the epicardial arteries. It also has a potential for restoring the contractile function during subsequent myocardial revascularization, which requires its more detailed research. Most methods for assessing coronary collaterals are carried out to define the potential of their use for Retrograde chronic total occlusion recanalization. Currently, the most widely used method for assessing collateral blood flow is angiography, which, despite its relative simplicity and good knowledge, has following limitations: invasiveness, operator dependence, limited visualization, etc. At the same time, a number of other diagnostic methods can also be used to assess collateral flow. This review article is aimed at a detailed study of modern invasive and non-invasive methods for assessing the development and function of collateral vessels.

Stent Graft Outcomes in Dialysis Circuits: A Review of Clinical Trials and Literature.

End-stage renal disease is a prevalent medical condition causing significant problems as the majority of patients are being treated with dialysis. While dialysis provides a means to compensate for the renal impairment, arteriovenous grafts and fistulas are often complicated by neointimal hyperplasia, loss of primary patency, and graft failure. Over the last decade, stent grafts have emerged as an alternative to balloon angioplasty and bare metal stents for revascularization in the event of arteriovenous graft occlusion or stenosis. Several randomized controlled trials have investigated the efficacy of stent grafts compared with balloon angioplasty for improving the function and durability of dialysis circuits. In this review, we present a comprehensive review of clinical trials. Stent grafts appear to offer increased primary patency over balloon angioplasty in the treatment of dialysis circuit stenosis. However, there is generally no significant difference between the two treatment modalities on other clinically relevant measures like complication rates and overall survival.

Association between the triglyceride glucose index and coronary collateralization in coronary artery disease patients with chronic total occlusion lesions

BackgroundRecent studies have substantiated the role of the triglyceride glucose (TyG) index in predicting the prognosis of coronary artery disease (CAD) patients, while no relevant studies have revealed the association between the TyG index and coronary collateralization in the event of coronary chronic total occlusion (CTO). The current study intends to explore whether, or to what extent, the TyG index is associated with impaired collateralization in CAD patients with CTO lesions.MethodsThe study enrolled 1093 CAD patients undergoing cardiac catheterization for at least one CTO lesion. Data were collected from the Beijing Anzhen Hospital record system. The degree of collaterals was determined according to the Rentrop classification system. The correlation between the TyG index and coronary collateralization was assessed.ResultsOverall, 318 patients were included in a less developed collateralization (Rentrop classification 0-1) group. The TyG index was significantly higher in patients with impaired collateralization (9.3±0.65 vs. 8.8±0.53, P<0.001). After adjusting for various confounding factors, the TyG index remained correlated with the occurrence of impaired collateralization, with odds ratios (ORs) of 1.59 and 5.72 in the T2 and T3 group compared with the first tertile group (P<0.001). In addition, subgroup analysis showed that higher TyG index values remained strongly associated with increased risk of less developed collateralization. To compare the risk assessment efficacy for the formation of collateralization between the TyG index and other metabolic abnormality indicators, an area under the receiver-operating characteristic (ROC) curve (AUC) was obtained. A significant improvement in the risk assessment performance for impaired collateralization emerged when adding the TyG index into a baseline model.ConclusionsThe increased TyG index is strongly associated with less developed collateralization in CAD patients with CTO lesions and its risk assessment performance is better than single metabolic abnormality indicators.

Outcomes after Endovascular Stent Placement for Long-Segment Superficial Femoral Artery Lesions

Endovascular intervention is commonly pursued as first-line management of symptomatic, long-segment superficial femoral artery (SFA) disease. The relative effectiveness and comparative long-term outcomes among bare metal stents (BMS), covered stents (CS), and drug-eluting stents (DES) for long-segment SFA lesions remain uncertain. A retrospective cohort study identified patients with symptomatic SFA lesions measuring at least 15cm in length who successfully received an endovascular stent (BMS, CS, or DES). The outcomes were patency, patient presentation upon stent occlusion, amputation-free survival (AFS), and all-cause mortality. Proportional hazards regressions and a multinomial logistic regression model were used to control for significant confounders. A total of 226 procedures were analyzed (BMS: 95 [42%]; CS: 74 [33%]; DES: 57 [25%]). There were no significant differences among the 3 stent types with respect to age, prevalence of either diabetes or end-stage renal disease, or smoking history. The median length of the SFA lesion varied across the cohorts (BMS: 28cm [interquartile range, IQR 20-30]; CS: 26cm [IQR 20-30]; DES: 20cm [IQR 16-25]; P=0.002). The unadjusted primary patency of BMS at 12, 24, and 48 month following index stent placement was 57%, 47%, and 44%, respectively. This is compared to 62%, 49%, and 42% for CS, and 81%, 66%, and 53% for DES, respectively (log-rank P=0.044). In adjusted models, however, there were no significant differences in primary patency among the stent types. Compared to CS however, DES was associated with improved primary-assisted patency (hazard ratio [HR] for patency loss: 0.35, P=0.008) and secondary patency (HR: 0.32, P=0.011). Across the entire follow-up period, stent occlusions occurred in 38 (40%) BMS cases, 42 (57%) CS, and 11 (19%) DES (P<0.001). Of these, acute limb ischemia (ALI) occurred in 2 (5%) BMS cases, 14 (33%) CS, and 1 (9%) DES (P=0.010). After adjustment, the relative risk of presenting with ALI as opposed to claudication was 27 times greater among patients re-presenting with occluded CS compared to BMS (P=0.020). There were no significant differences in AFS or all-cause mortality across the 3 cohorts. For long-segment SFA lesions, DES is associated with improved primary-assisted and secondary patency over long-term follow-up. In the event of stent occlusion, CS is associated with an increased risk of ALI.

Elevated repulsive guidance molecule-a mRNA in peripheral blood mononuclear cells are associated with impaired leptomeningeal collaterals in patients with middle cerebral artery occlusions.

In the event of middle cerebral artery occlusion (MCAO), leptomeningeal collaterals (LMCs) play a crucial role in determining the survival of brain tissue distal to occlusion. Previous findings indicated that genes controlling arteriogenesis can impact the extent of LMCs. Therefore, probe for potential genetic parameters correlating of arteriogenesis may be clinically useful in predicting LMCs status in MCAO. During the screening process, we focused on repulsive guidance molecule a (RGMa), which has been reported to play a negative role in angiogenesis after stroke by decreasing the proliferation, migration, and tube formation of endothelial cells (ECs) in vivo and in vitro. Indeed, endothelial function plays a main role in arteriogenesis and is essential in determining the LMCs status. Therefore, in present study, we aimed to testify the hypothesis that RGMa might be associated with LMCs status in MCAO. We prospectively enrolled patients with acute M1 MCA +/- intracranial internal carotid artery (ICA) occlusions (n=96) and healthy controls (n=33). Status of LMCs was evaluated according to computed tomographic angiography (CTA) on admission. Baseline RGMa mRNA expression was quantified by using quantitative real-time PCR. Patients with poor LMCs showed significantly higher RGMa mRNA levels than patients with good LMCs status (P=0.001) as well as healthy controls (P=0.002), respectively; whereas good LMCs group showed similar baseline RGMa levels than controls (P=1.000). RGMa mRNA level and baseline NIHSS score were independent predictors for impaired LMCs. In MCAO patients, elevated PBMCs RGMa mRNA levels were associated with impaired LMCs status, indicating that measurement of RGMa mRNA expression in the early phase of stroke, together with other clinical approaches, was logically expected to be useful for predicting LMCs status. Moreover, a role for RGMa in leptomeningeal arteriogenesis following ischemic stroke can be hypothesized.

How Imaging Can Help Us Better Understand the Migraine-Stroke Connection.

Migraine and stroke are among the most prevalent and disabling neurological diseases. Epidemiologic studies showed that there is an association between migraine and stroke. Migraineurs, especially those with aura, are more likely to develop subclinical infarct-like lesions in the brain and are at risk for cryptogenic or cardioembolic stroke. Migrainous headache can be found at the onset of acute ischemic stroke in some patients, and in rare instances, an infarction can be directly attributed to a prolonged migraine aura, ie, migrainous infarction. Importantly, recent studies suggest that in the event of cerebral artery occlusion, even a history of migraine is sufficient to accelerate infarct progression and worsen outcomes. The mechanisms underlying the migraine-stroke connection are multifactorial, with genetic predisposition, aura-related electrophysiological mechanisms (cortical spreading depolarization), and cerebral microembolism being the most convincing ones at this point. Here, we provide a comprehensive overview on recent imaging studies that have helped us better understand the complex association between migraine and stroke.

Feasibility and safety of endoscopic ultrasound-guided gallbladder drainage using a newly designed lumen-apposing metal stent.

Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) is increasingly accepted as an effective treatment option in patients who require drainage for acute cholecystitis. A newly designed lumen-apposing metal stent (LAMS) has been introduced recently in this procedure. In this study, we evaluated the feasibility and safety of the newly designed LAMS in patients with acute cholecystitis who were unsuitable for cholecystectomy. Between Mar 2017 and Oct 2017, 22 patients with acute cholecystitis who were unsuitable for cholecystectomy underwent EUS-GBD with the newly designed LAMS. We evaluated the technical and clinical success and the adverse event profiles. EUS-GBD with newly designed LAMS was technically and clinically successful in 21 of the 22 patients. EUS-GB stenting was performed at urgent setting in 17 patients, while 5 patients, who had undergone initial PTGBD, underwent EUS-GB stenting to remove PTGBD tube. The median procedure time was 11.5 (range 8.8-17.0) min. A late adverse event of stent occlusion developed in one patient. Stent migration was not observed during follow-up (median 318.0 days, range 39.0-398.0days) and cumulative stent patency rate at 1year was 95%. EUS-GBD with newly designed LAMS is feasible and shows acceptable safety profiles for both the urgent drainage of acute cholecystitis and elective internalization following PTGBD in patients with high surgical risk.

The use of GTN paste in impending necrosis following soft-tissue augmentation

One of the actions of Glyceryl trinitrate (GTN), otherwise known as nitroglycerin, is initiating the relaxation of smooth muscle cells in blood vessels to promote blood flow to various parts of the body. GTN comes in a number of forms and has a range of indications; however, unfortunately GTN has some common side effects, which in some cases may limit therapy. These side effects include flushing, headache and postural hypotension. One significant, yet controversial, off-license use for GTN paste is for the adjunctive treatment of necrosis or impending necrosis following the use of dermal fillers for soft tissue augmentation. In the event of occlusion or damage and impending necrosis, the goal is to promote blood flow to the area as quickly as possible and treatment should always be immediate. Emergency treatment of the area with hyaluronidase should be initiated first, with adjunct treatments to improve blood supply to the area following shortly.

Posterior communicating artery occlusion and recanalization through a fusiform aneurysm after flow diversion

Occlusion of branch vessels is a known potential sequela of the treatment of intracranial aneurysms with flow diversion. We present a case of occlusion and distal reconstitution of the origin of the posterior communicating artery through a fusiform aneurysm of the internal carotid artery after flow diversion. A 56-year-old woman was incidentally found to have a large fusiform aneurysm of the posterior communicating segment of the internal carotid artery incorporating the origin of the posterior communicating artery. The aneurysm was treated with placement of a Pipeline flow diverter. Follow-up computed tomography angiogram at 7 months demonstrated no change in aneurysm filling. A follow-up digital subtraction angiogram at 12 months demonstrated occlusion of the native origin of the posterior communicating artery with distal reconstitution through two accessory channels through the aneurysm. The remainder of the aneurysm was thrombosed. The patient had not had any clinical symptoms during this event. The unorganized nature of the thrombus within aneurysms after flow diversion may allow accessory vascular channels to form in the event of occlusion of a side branch.

Su1401 FEASIBLITY AND SAFETY OF EUS-GUIDED GALLBLADDER DRAINAGE WITH NEW LUMEN APPOSING METAL STENT (SPAXUS) IN PATIENTS WITH ACUTE CHOLECYSTITIS WHO ARE UNSUITABLE FOR CHOLECYSTECTOMY

Endoscopic ultrasound (EUS) guided gallbladder drainage increasingly accepted as an effective alternative to percutaneous drainage in a patient who needs drainage for acute cholecystitis. Stent migration is the main obstacles in EUS guided gallbladder drainage (EUS-GBD) with conventional biliary metal stent. To overcome this adverse event, a lumen apposing metal stent (LAMS) has recently been introduced in this procedure. In this study, we have evaluated the feasibility and safety of newly developed LAMS (SPAXUS®) in patients with acute cholecystitis who were unsuitable for cholecystectomy. Between Mar 2017 to Oct 2017, a total of 22 patients with acute cholecystitis who did not respond to initial medical treatment and were unsuitable cholecystectomy were enrolled. We evaluated technical, clinical success and adverse event profiles. EUS-GBD with newly developed LAMS was technically and clinically successful in 21/22 patients. Mean procedure time was 12.5 ± 5.0 minutes. Purpose of EUS-GBD was urgent drainage in 17 and establish of internal drainage before percutaneous transhepatic gallbladder drainage (P-GBD) removal in 5 patients. Early adverse events were occurred in 2/21 patients (1 stent occlusion by stone and 1 pyloric ring obstruction by proximal flange of SPAXUS). In the cases with pyloric ring obstruction, pyloric stent was applied temporarily. In 10 patients, direct cholecystoscopy was conducted one or two days after EUS-GBD Late adverse event of stent occlusion developed in 1/21 patients. Stent migration was not observed during follow up period. P-GBD removal was possible in all 5 patients who underwent EUS-GBD for internal drainage before P-GBD removal. Mean stent patency duration was 162.5 days (95% CI 146.37-178-63). EUS-GBD with new lumen apposing metal stent is technically feasible and shows acceptable safety profile in patients with acute cholecystitis who has high surgical risk.

Adult Wilms tumor with inferior vena cava thrombus and distal deep vein thrombosis \u2013 a case report and literature review

BackgroundAdult Wilms tumor (WT, nephroblastoma) is a rare, but well-described renal neoplasm. Although inferior vena cava tumor thrombosis is present in up to 10% of Wilms tumors in childhood, only few cases of this clinical manifestation in adults have been reported. To the best of our knowledge, this is the first case of adult WT infiltrating into inferior vena cava (IVC) with concomitant distal deep vein thrombosis.Case presentationA 28-year-old male patient with gross hematuria and right flank pain was diagnosed with right kidney tumor penetrating to IVC. Preoperatively, acute distal thrombosis in inferior vena cava and lower extremities veins occurred. Right radical nephrectomy with tumor thrombectomy via cavotomy was performed. In order to prevent pulmonary embolism, IVC was ligated below left renal vein level. Histopathological examination revealed a triphasic nephroblastoma without anaplastic features. Postoperatively, patient was diagnosed with metastatic liver disease, which was treated with two lines of chemotherapy followed by radiotherapy with achievement of complete response.ConclusionsAdult WT occurs usually in young patients, under 40 years of age. Neoadjuvant chemotherapy proved to be effective in children, resulting with tumor shrinkage and venous tumor thrombus regression. Therefore, percutaneous biopsy should be always considered in young patients presenting with renal tumor invading venous system. IVC ligation is a safe treatment option in the event of complete inferior vena cava occlusion due to distal thrombosis concomitant to tumor thrombus, provided collateral venous pathways are well-developed.

Occlusion-Aware Correlation Particle Filter Target Tracking Based on RGBD Data

In recent decades, there have been considerable improvements in target-tracking algorithms. However, aspects such as target occlusion, scale variation, and illumination changes still present significant challenges to existing algorithms. In this paper, we describe an occlusion-aware correlation particle filter target-tracking method based on RGBD data. First, we derive a target occlusion judgment mechanism based on a depth image and the histogram of oriented gradients (HOG) feature. We then formulate the tracking mechanism for the target prediction–tracking–optimization–redetection process using a correlation maximum likelihood estimation particle filter algorithm. We propose an adaptive update strategy whereby the system saves a well-tracked model when no occlusion occurs, and then uses this saved model to replace poorly tracked models in the event of occlusion. Furthermore, we consider the scale variation and adjust the target size according to the depth image, but we leave the HOG feature vector dimension of the target area unchanged. Thus, the problems such as model offset, scale variation, and loss of features are corrected over time. The experimental results demonstrate that the proposed target-tracking algorithm can detect target occlusion and track targets well, requires fewer calculations to perform target prediction–tracking–optimization–redetection, reduces the impact of illumination changes, and achieves better real-time performance and accuracy than many existing algorithms.

Voxel based analysis of recurrence dynamics in intracranial aneurysms after coiling

BackgroundUnderstanding aneurysm growth is critical for the appropriate follow-up of patients after coil embolization and the need for retreatment. The purpose of the study was to stratify the growth dynamics...

Fully automated stroke tissue estimation using random forest classifiers (FASTER)

Several clinical trials have recently proven the efficacy of mechanical thrombectomy for treating ischemic stroke, within a six-hour window for therapy. To move beyond treatment windows and toward personalized risk assessment, it is essential to accurately identify the extent of tissue-at-risk (“penumbra”). We introduce a fully automated method to estimate the penumbra volume using multimodal MRI (diffusion-weighted imaging, a T2w- and T1w contrast-enhanced sequence, and dynamic susceptibility contrast perfusion MRI). The method estimates tissue-at-risk by predicting tissue damage in the case of both persistent occlusion and of complete recanalization. When applied to 19 test cases with a thrombolysis in cerebral infarction grading of 1–2a, mean overestimation of final lesion volume was 30 ml, compared with 121 ml for manually corrected thresholding. Predicted tissue-at-risk volume was positively correlated with final lesion volume (p < 0.05). We conclude that prediction of tissue damage in the event of either persistent occlusion or immediate and complete recanalization, from spatial features derived from MRI, provides a substantial improvement beyond predefined thresholds. It may serve as an alternative method for identifying tissue-at-risk that may aid in treatment selection in ischemic stroke.

Atheromatous Occlusive Lesions of the Popliteal Artery Treated with Stent Grafts: Predictive Factors of Midterm Patency

Because of its location, the popliteal artery is exposed to important biomechanical constraints, inducing a specific risk of thrombosis of stents, little studied in the literature. The objective of this monocentric retrospective study was to evaluate the patency of stents implanted in the popliteal artery to treat atheromatous lesions and the risk factors predisposing to thrombosis. Between January 2009 and July 2013, all the patients receiving stents for a residual stenosis or a complication of angioplasty in the popliteal artery or the distal anastomosis of a femoropopliteal bypass were included retrospectively and in an intention to treat. Forty-six patients (17 women), with a 71.5years median age (range, 45-90years), including 17 diabetic patients (37%) and 7 hemodialysis patients (15%), were operated in 51 limbs for claudication (n=25, 49%), critical ischemia (n=18, 35%), or acute ischemia (n=8, 16%). Thirty stenoses >70% (59%) and 21 thromboses (41%) were treated with 56 autoexpandable stents, with an average diameter of 6mm (range, 5-8mm) and an average length of 5cm (range, 4-15cm), including 39 lesions in P1 (above the patella), 8 in P2 (articular), and 4 in P3 (distal popliteal artery). The following factors were analyzed according to univariate and multivariate models: age, gender, Society for Vascular Surgery score, symptomatology, type and location of lesion, number of stents deployed, and dimension of stents. Technical success was of 98% (n=50), including 1 insufficient result of the endovascular treatment. At 30days, one patient treated for critical ischemia died (2%) and one residual popliteal stenosis was treated by bypass (2%). After a 27.6±10.07month follow-up, restenosis (>50%) was detected in 5 cases including 4 asymptomatic and a popliteal thrombosis occurred in 9 cases, including 3 asymptomatic cases. Eight secondary interventions were necessary, including 4 endovascular procedures, 3 bypasses, and only 1 major amputation (thigh). The primary and secondary patencies at 12months and 24months were 80% and 65%, and 90% and 74%, respectively. The multivariate analysis showed that the type of lesion (stenosis versus occlusion; odds ratio [OR], 5.1; 95% confidence interval [CI], 1.2-22.9, P=0.032) and the number of stents implanted (1 vs. 2 stents; OR [95% CI], 12.7 [1.8-88.5]; P=0.011) were independent predictive factors of secondary thrombosis. The endovascular treatment of the atheromatous popliteal lesions appears to be a satisfactory alternative. The implantation of 1 stent in the popliteal artery is recommended in the event of popliteal occlusion, whereas for a stenosis, it must be reserved for patients with residual stenosis or in the event of complications of angioplasty, such as dissection or elastic recoil. Stent must be single, with deployment of a long stent in the event of long lesion.

Neurovascular Regulation in the Ischemic Brain

The brain has high energetic requirements and is therefore highly dependent on adequate cerebral blood supply. To compensate for dangerous fluctuations in cerebral perfusion, the circulation of the brain has evolved intrinsic safeguarding measures. The vascular network of the brain incorporates a high degree of redundancy, allowing the redirection and redistribution of blood flow in the event of vascular occlusion. Furthermore, active responses such as cerebral autoregulation, which acts to maintain constant cerebral blood flow in response to changing blood pressure, and functional hyperemia, which couples blood supply with synaptic activity, allow the brain to maintain adequate cerebral perfusion in the face of varying supply or demand. In the presence of stroke risk factors, such as hypertension and diabetes, these protective processes are impaired and the susceptibility of the brain to ischemic injury is increased. One potential mechanism for the increased injury is that collateral flow arising from the normally perfused brain and supplying blood flow to the ischemic region is suppressed, resulting in more severe ischemia. Approaches to support collateral flow may ameliorate the outcome of focal cerebral ischemia by rescuing cerebral perfusion in potentially viable regions of the ischemic territory.