Intraluminal Diameter Research Articles

Prolonged mechanical ventilation increases diaphragm arteriole circumferential stretch without changes in stress/stretch: Implications for the pathogenesis of ventilator-induced diaphragm dysfunction.

Prolonged mechanical ventilation (MV; ≥6h) results in large, time-dependent reductions in diaphragmatic blood flow and shear stress. We tested the hypothesis that MV would impair the structural and material properties (ie, increased stress/stretch relation and/or circumferential stretch) of first-order arterioles (1A) from the medial costal diaphragm. Shear stress was estimated from isolated arterioles and prior blood flow data from the diaphragm during spontaneous breathing (SB) and prolonged MV (6h MV). Thereafter, female Sprague-Dawley rats (~5months) were randomly divided into two groups, SB (n=6) and 6h MV (n=6). Following SB and 6h MV, 1A medial costal diaphragm arterioles were isolated, cannulated, and subjected to stepwise (0-140cmH2 O) increases in intraluminal pressure in calcium-free Ringer's solution. Inner diameter and wall thickness were measured at each pressure step and used to calculate wall:lumen ratio, Cauchy-stress, and circumferential stretch. Compared to SB, there was a ~90% reduction in arteriolar shear stress with prolonged MV (9±2 vs 78±20dynes/cm2 ; p≤.05). In the unloaded condition (0cmH2 O), the arteriolar intraluminal diameter was reduced (37±8 vs 79±13μm) and wall:lumen ratio was increased (120±18 vs 46±10%) compared to SB (p≤.05). There were no differences in the passive diameter responses or the circumferential stress/stretch relationship between groups (p>.05), but at each pressure step, circumferential stretch was increased with 6h MV vs SB (p≤.05). During prolonged MV, medial costal diaphragm arteriolar shear stress is severely diminished. Despite no change in the material behavior (stress/stretch), prolonged MV resulted in altered structural and mechanical properties (ie, elevated circumferential stretch) of medial costal diaphragm arterioles. This provides important novel mechanistic insights into the impaired diaphragm blood flow capacity and vascular dysfunction following prolonged MV.

Arterial evaluation of systemic sclerosis patients with Doppler ultrasound: What did we find?

The aim of this study was to detect macrovascular findings in systemic sclerosis (SSc) by means of color Doppler ultrasonography (CDUS) and to evaluate the relationship between the laboratory and clinical findings in the setting of the disease. This was a cross-sectional study. Eighty-eight patients were included in the study. CDUS examinations of the bilateral carotid, vertebral, and peripheral arteries were performed. The presence of macrovascular involvement was investigated and recorded, and its relationships with the clinical, laboratory, and cardiovascular risk factors were evaluated. An atheromatous plaque was found in 67.7% of the 1936 arteries examined by CDUS. Of these 1936 arteries, 37.4% demonstrated a narrowing of the intraluminal diameter. On the other hand, the carotid intima-media thickness (CIMT) was found to have increased in 55.7% of the patients. This increase was found to be statistically correlated with disease duration, the modified Rodnan Skin Thickness Score, and the Medsger Disease Activity Score. But no relation existed with the disease subtype, age, or cardiovascular risk factors. Arterial occlusion was detected in 10 patients. An association was found between the CIMT values and arterial occlusion. In this study, we examined the arteries by means of CDUS, and we detected structural alterations in the peripheral and carotid arteries. We witnessed that these macrovascular changes had a close association with certain features of SSc. We think there is a need for broader prospective studies in order to evaluate the contribution of these factors to the macrovascular changes stated in the article.

Enhancement of Endothelial KCa Channel Activity as a Novel Strategy to Oppose Atherosclerosis

Atherosclerosis is a harmful cardiovascular condition in which low-density lipoprotein cholesterol (LDL-C) elevates in the blood, passes through the arterial endothelium, and promotes endothelial dysfunction (ED). ED can facilitate fatty plaque formation, which decreases intraluminal arterial diameter and blood flow, and increases arterial stiffness. A hallmark feature of ED is decreased bioavailability of nitric oxide (NO), a pluripotent compound with vasodilatory effects, along with anti-inflammatory and anti-proliferative actions in the arterial wall. Our group has previously reported that pharmacological activation of endothelial Ca2+-activated K+ channels, i.e. KCa2.3 and KCa3.1, can reverse ED, in part by enhancing endothelial NO production. Given the contributions of ED and NO in atherosclerosis, we hypothesize that enhancing endothelial function will mitigate the development and/or severity of atherosclerosis. The aim of this proof-of-concept study is to determine whether prolonged administration of the KCa channel activator SKA-31 in vivo can mitigate atherosclerosis by decreasing ED, arterial stiffness and/or fatty plaque formation. In this presentation, I will describe preliminary data obtained during the initial phase of this study. To mimic human atherosclerosis, we are using male Apoe knockout (Apoe-/-) mice, which begin to develop signs of progressive aortic injury at ~8 weeks of age. Experimentally, Apoe-/- mice on a regular chow diet receive one of three daily treatments for 16 weeks: SKA-31 (10 mg/kg), the KCa3.1 channel blocker senicapoc (40 mg/kg) or drug vehicle alone. As previous studies have reported that KCa3.1 channel blockers can reduce atherosclerotic events, we are using this treatment condition as a benchmark in our study. Drugs are formulated in miglyol and condensed milk, which is readily ingested by the mice. Plasma LDL-C levels are being measured to determine whether drug treatment modifies the levels of this important pathogenic molecule. Echocardiography is being used to measure standard cardiac function, along with aortic flow and pulse wave velocity as markers of arterial stiffness. Following euthanasia, vasodilatory responses of the aorta are examined by wire myography to determine whether drug treatment improves endothelial function. Histopathological analyses are being performed to elucidate aortic structure and integrity (with H&E staining) and the extent of atherosclerotic plaque formation in the aorta (with Oil Red O staining). Lastly, macrophage proliferation in the aortic wall will be assessed by immunocytochemistry, as macrophages proliferate rapidly in fatty plaque sites. Positive results from this study will facilitate future research to investigate the underlying cellular mechanisms by which endothelial KCa channel activation opposes atherogenesis.

Intraluminal Stent Optimization for the Baerveldt Glaucoma Implant: An Experimental Study.

Our laboratory study determined the approximate suture diameter for use in intraluminal stenting of the Baerveldt glaucoma implant (BGI) to prevent postoperative hypotony. Commercial 3-0 monofilament nylon sutures which are commonly used may vary significantly outside of this diameter. Postoperative hypotony is a complication of surgical treatment of glaucoma using the BGI. One method utilized to prevent early postoperative hypotony is intraluminal stenting of the implant with monofilament sutures. The present study attempted to determine optimal stent diameter in microns for 3-0 monofilament sutures to reduce outflow and thereby reduce the risk of postoperative hypotony using the BGI. A laboratory bench model of the anterior chamber was utilized to measure the outflow rate of balanced salt solution through the BGI at pressures of 20 and 40 mm Hg while utilizing commercially available 3-0 monofilament nylon stents of various diameters. The BGI tube has an inner diameter of 300 µm. In addition, 3-0 nylon sutures were studied for variability by measuring the diameters at 10 equally spaced points along the length of each sample using a digital micrometer. Average experimental flow rates decreased with increasing intraluminal stent diameter and increased with increasing pressure. An intraluminal stent diameter of 250 µm yielded a flow rate of 40 µL/min at a nominal pressure of 20 mm Hg. Diameters of the tested 3-0 monofilament nylon sutures were all within the United States Pharmacopeia diameter range of 200 to 250 µm, but diameters varied significantly depending on the manufacturer. In our laboratory model, the optimal stent diameter to reduce aqueous flow to a level approaching the normal aqueous production is at least 250 µm. Secondarily, commercially available 3-0 monofilament nylon suture materials showed variable diameters within the United States Pharmacopeia diameter range.

Transient receptor potential channel-dependent myogenic responsiveness in small-sized resistance arteries.

It is well documented that the inherent ability of small arteries and arterioles to regulate intraluminal diameter in response to alterations in intravascular pressure determines peripheral vascular resistance and blood flow (termed myogenic response or pressure-induced vasoconstriction/dilation). This autoregulatory property of resistance arteries is primarily originated from mechanosensitive vascular smooth muscle cells (VSMCs). There are diverse biological apparatuses in the plasma membrane of VSMCs that sense mechanical stimuli and generate intracellular signals for the contractility of VSMCs. Although the roles of transient receptor potential (TRP) channels in pressure-induced vasoconstriction are not fully understood to date, TRP channels that are directly activated by mechanical stimuli (e.g., stretch of VSMCs) or indirectly evoked by intracellular molecules (e.g., inositol trisphosphate) provide the major sources of Ca2+ (e.g., Ca2+ influx or release from the sarcoplasmic reticulum) and in turn, evoke vascular reactivity. This review sought to summarize mounting evidence over several decades that the activation of TRP canonical, TRP melastatin, TRP vanilloid, and TRP polycystin channels contributes to myogenic vasoconstriction.

Anatomic Considerations of Microvascular Free Tissue Transfer in Endoscopic Endonasal Skull Base Surgery

Objective Though microvascular free tissue transfer is well established for open skull base reconstruction, normative data regarding flap design and inset after endoscopic endonasal skull base surgery (ESBS) is lacking. We aim to describe anatomical considerations of endoscopic endonasal inset of free tissue transfer of transclival (TC) and anterior cranial base resection (ACBR) defects. Design and Setting Radial forearm free tissue transfer (RFFTT) model. Participants Six cadaveric specimens. Main Outcome Measures Pedicle orientation, pedicle length, and recipient vessel intraluminal diameter. Results TC and ACBR defects averaged 17.2 and 11.7 cm 2 , respectively. Anterior and lateral maxillotomies and endoscopic medial maxillectomies were prepared as corridors for flap and pedicle passage. Premasseteric space tunnels were created for pedicle tunneling to recipient facial vessels. For TC defects, the RFFTT pedicle was oriented cranially with the flap placed against the clival defect (mean pedicle length 13.1 ± 0.6 cm). For ACBR defects, the RFFTT pedicle was examined in three orientations with respect to anterior-posterior axis of the RFFTT: anteriorly, posteriorly, and laterally. Lateral orientation offered the shortest average pedicle length required for anastomosis in the neck (11.6 ± 1.29 cm), followed by posterior (13.4 ± 0.7cm) and anterior orientations (14.4 ± 1.1cm) ( p < 0.00001, analysis of variance). Conclusions In ACBR reconstruction using RFFTT, our data suggests lateral pedicle orientation shortens the length required to safely anastomose facial vessels and protects the frontal sinus outflow anteriorly while limiting pedicle exposure through a maxillary corridor within the nasal cavity. With greater understanding of anatomical factors related to successful preoperative flap planning, free tissue transfer may be added to the ESBS reconstruction ladder.

Endothelial inflammatory and thrombogenic expression changes in microvascular anastomoses – An immunohistochemical analysis

The aim of this study was to investigate intraluminal vessel diameters and endothelial expression levels of pro-inflammatory and -thrombotic mediators in patent and non-patent microvascular anastomoses.Endothelial expression of CD31, VCAM-1, E− and P-Selectin, eNOS, iNOS and PAI-1 was evaluated by immunohistochemistry and compared to non-anastomosed arteries as controls. Intraluminal diameters were determined via H.E.-staining.In 20 human anastomoses (8 patent, 12 non-patent) neither the analysis of endoluminal de-endothelialization (p = 0.966) nor luminal narrowing (p = 0.750) revealed any significant differences between patent and non-patent microanastomoses. Expressions of pro-inflammatory mediators were significantly higher in patent anastomoses compared to controls but did not show any difference compared to non-patent anastomoses (p > 0.050). iNOS was higher in non-patent compared to patent anastomoses (p = 0.030) and controls (p = 0.001), whereas eNOS did not reveal any differences between these groups (p = 0.611 and p = 0.130). In non-patent anastomoses PAI-1 was expressed higher compared to patent anastomoses and controls (p = 0.021 and p < 0.001).Irrespective of their patency, anastomoses are characterized by endothelial dysfunction with a pro-inflammatory and pro-thrombotic milieu. Avoiding endothelial trauma during suturing is essential in order not to aggravate existing endothelial dysfunction in microanastomoses. Additionally, the influence of medication-related changes on anastomoses should be investigated as this is still an indistinctive topic.

872 Racial differences in spiral artery remodeling

Maternal race is a determinant of the frequency and severity of ischemic placental disease. Current Doppler methods infer, but do not directly assess, function of the spiral arteries (SA), the root of placental dysfunction. We developed a novel ultrasound method combining B-flow, spatiotemporal image correlation (STIC) and M-Mode to image and measure SA intraluminal diameter during the maternal cardiac cycle in both systole (S) and diastole (D)(Fig 1). We tested the hypothesis that measurable SA function differs between races. In an IRB-approved prospective longitudinal observational study, we defined a supernormal population (parity=0, no co-morbidities or pregnancy complications) to control covariables. S and D were quantified in all trimesters, with a compound ultrasound technique: In B-flow mode, STIC/4D image blocks of individual SA were acquired systematically in the placental bed. S and D diameters were measured via M-Mode. At the first trimester visit, serum analytes (PAPP-A, PlGF, AFP) were obtained. At each visit, BMI, mean arterial blood pressure, mean uterine artery-PI, gestational age (GA), race and age were recorded. Quality control included formal training, written criteria for image acceptance and screening of every image by senior study personnel, all blinded to patient characteristics/outcome. Longitudinal analysis utilized a linear mixed-effects model with random intercept and random slope. A total of 645 SA were measured serially in 43 women (15 each) at 11-32 weeks. Women self-assigned race as Black (24), White (14) or Asian (5). S and D diameters rose with GA (p<0.001 for both). S was significantly higher in W than B and A (Fig 2) The model showed significant interaction between S and PAPP-A (p<0.0001). The study shows B-flow/M-mode can detect and quantify SA remodeling and illustrates the normal loss of mural tone of these vessels as pregnancy advances. Even when pregnancy outcome is normal, black women show less remodeling, a potential clue to their liability for placental dysfunction across pregnancy and the puerperium.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Ultrasound Evaluation of Endo-AVF Using a Dialysis Access Clamp

Percutaneous endovascular arteriovenous fistula (Endo-AVF) is a minimally invasive alternative to conventional surgical dialysis access. Endo-AVF may represent a significant advance in the creation of dialysis access but may require a variety of additional procedures to achieve adequate flow. To maximize flow through the cephalic vein, usually the preferred vessel, it may be necessary to permanently occlude competing outflow branches such as the brachial or basilic vein. Ultrasound monitoring of cephalic vein flow in the vascular lab can be used to predict the efficacy of basilic vein ligation but requires 2 operators to perform. We developed a simple technique to temporarily obstruct basilic vein outflow using a standard dialysis clamp that can be performed by a single vascular technologist. With the patient in the supine position, the spring-loaded dialysis clamp is positioned over the basilic vein in the upper arm using ultrasound guidance. The clamp applies mild, painless obstruction of the basilic vein without interfering with arterial inflow or cephalic vein outflow. Cephalic vein peak systolic velocity, intraluminal diameter, and flow volume are recorded. This technique was used in 6 patients, 4 to 6 weeks, following the initial Endo-AVF procedure. Ultrasound surveillance confirmed that the basilic vein outflow was effectively occluded in all 6 cases. The same ultrasound machine was used in all 6 studies. Cephalic vein flow increased significantly in each case (pre-clamp cephalic flow volume 301 ± 66.8 mL/min vs post-clamp 702 ± 156.5 mL/min after, P = 1.0). Ultrasound observation of the basilic vein post-clamp application concluded there were no complications related to the use of the dialysis clamp. The average duration of the procedure was less than 20 minutes. We have successfully developed a simple non-invasive technique to predict the effect of basilic vein occlusion on cephalic vein flow that can be accomplished by a sole vascular technologist. This technique can be used to guide the need for embolization of the basilic vein.

Tunica-Specific Transcriptome of Abdominal Aortic Aneurysm and the Effect of Intraluminal Thrombus, Smoking, and Diameter Growth Rate

There is no medical treatment to prevent abdominal aortic aneurysm (AAA) growth and rupture, both of which are linked to smoking. Our objective was to map the tunica-specific pathophysiology of AAA with consideration of the intraluminal thrombus, age, and sex, and to subsequently identify which mechanisms were linked to smoking and diameter growth rate. Approach and Results: Microarray analyses were performed on 246 samples from 76 AAA patients and 13 controls. In media and adventitia, there were 5889 and 2701 differentially expressed genes, respectively. Gene sets related to adaptive and innate immunity were upregulated in both tunicas. Media-specific gene sets included increased matrix disassembly and angiogenesis, as well as decreased muscle cell development, contraction, and differentiation. Genes implicated in previous genome-wide association studies were dysregulated in media. The intraluminal thrombus had a pro-proteolytic and proinflammatory effect on the underlying media. Active smoking resulted in increased inflammation, oxidative stress, and angiogenesis in all tissues and enriched lipid metabolism in adventitia. Processes enriched with active smoking in control aortas overlapped to a high extent with those differentially expressed between AAAs and controls. The AAA diameter growth rate (n=24) correlated with T- and B-cell expression in media, as well as lipid-related processes in the adventitia. This tunica-specific analysis of gene expression in a large study enabled the detection of features not previously described in AAA disease. Smoking was associated with increased expression of aneurysm-related processes, of which adaptive immunity and lipid metabolism correlated with growth rate.

Effects of preoperative visceral artery stenosis on target artery outcomes after fenestrated/branched endovascular aortic aneurysm repair

ObjectiveTarget artery stenosis might affect the outcomes of fenestrated/branched endovascular aortic aneurysm repair (F-BEVAR). The aim of the present study was to assess the effects of preoperative stenosis of the celiac artery (CA) and superior mesenteric artery (SMA) on the target artery outcomes after F-BEVAR. MethodsDuring a 4-year period, 287 consecutive patients, 204 men (71%) and 83 women (29%), had undergone F-BEVAR using fenestrated (83%), fenestrated-branched (4.5%), branched (3.5%), and off-the-shelf t-Branch (9%) devices (Cook Medical Inc, Bloomington, Ind). Preoperative SMA and CA significant stenosis was defined as a computed tomography angiography-based intraluminal diameter reduction >50%. The primary endpoints included primary patency, freedom from target vessel instability, and patient survival. ResultsThe median patient age was 71 years (interquartile range, 67-77 years). Suprarenal (36%), juxtarenal (25%), and thoracoabdominal (39%) aortic aneurysms were treated. The technical success rate was 99%. The 30-day survival was 97%. Among 981 stented vessels, 179 (18%) were CAs and 270 (27.5%) were SMAs. Significant preoperative CA stenosis was identified in 39 patients (22%) and SMA stenosis in 24 (9%). The median follow-up was 29.9 months. The primary patency rates at 12, 36, and 60 months were 98%, 92%, and 92% for the CA and 99%, 98%, and 98% for the SMA, respectively. Primary patency was significantly lower in the patients with previous significant CA stenosis than in those without stenosis (83%, 83%, and 76% vs 100%, 100%, and 97% at 12, 36, and 60 months, respectively; P < .01). Freedom from celiac branch instability was also significantly lower among patients with significant stenosis (84%, 84%, and 76% vs 100%, 93%, and 93% at 12, 36, and 60 months; P < .01). The presence of significant SMA stenosis did not affect either primary patency or freedom from target vessel instability. The survival rates at 12, 36, and 60 months were significantly lower for the patients with CA stenosis than for those without stenosis (67%, 61%, and 55% vs 90%, 84%, and 82%, respectively; P < .01). Similarly, lower survival rates were observed for patients with significant SMA stenosis (70%, 60%, and 60% vs 87%, 79%, and 78% at 12, 36, and 60 months, respectively; P = .04). ConclusionsF-BEVAR was associated with overall primary patency rates >90% for the CA and SMA. Preoperative CA stenosis was associated with lower primary patency and freedom from target vessel instability. In contrast, neither SMA branch primary patency nor freedom from target vessel instability were affected by preoperative SMA stenosis. We found visceral artery stenosis was a marker of atherosclerosis burden associated with reduced mid- and long-term patient survival.

DAPT, a potent Notch inhibitor regresses actively growing abdominal aortic aneurysm via divergent pathways.

Abdominal aortic aneurysm (AAA) is a localized pathological dilation of the aorta exceeding the normal diameter (∼20 mm) by more than 50% of its original size (≥30 mm), accounting for approximately 150000-200000 deaths worldwide per year. We previously reported that Notch inhibition does not decrease the size of pre-established AAA at late stage of the disease. Here, we examined whether a potent pharmacologic inhibitor of Notch signaling (DAPT (N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester)), regresses an actively growing AAA. In a mouse model of an aneurysm (Apoe-/- mice; n=44); DAPT (n=17) or vehicle (n=17) was randomly administered at day 14 of angiotensin II (AngII; 1 µg/min/kg), three times a week and mice were killed on day 42. Progressive increase in aortic stiffness and maximal intraluminal diameter (MILD) was observed in the AngII + vehicle group, which was significantly prevented by DAPT (P<0.01). The regression of aneurysm with DAPT was associated with reduced F4/80+Cd68+ (cluster of differentiation 68) inflammatory macrophages. DAPT improved structural integrity of aorta by reducing collagen fibrils abnormality and restoring their diameter. Mechanistically, C-C chemokine receptor type 7 (Ccr7)+F4/80- dendritic cells (DCs), implicated in the regression of aneurysm, were increased in the aorta of DAPT-treated mice. In the macrophages stimulated with AngII or lipopolysaccharide (LPS), DAPT reverted the expression of pro-inflammatory genes Il6 and Il12 back to baseline within 6 h compared with vehicle (P<0.05). DAPT also significantly increased the expression of anti-inflammatory genes, including c-Myc, Egr2, and Arg1 at 12-24 h in the LPS-stimulated macrophages (P<0.05). Overall, these regressive effects of Notch signaling inhibitor emphasize its therapeutic implications to prevent the progression of active AAAs.

AT2R agonist NP‐6A4 mitigates aortic stiffness and proteolytic activity in mouse model of aneurysm

Clinical and experimental studies show that angiotensin II (AngII) promotes vascular pathology via activation of AngII type 1 receptors (AT1Rs). We recently reported that NP‐6A4, a selective peptide agonist for AngII type 2 receptor (AT2R), exerts protective effects on human vascular cells subjected to serum starvation or doxorubicin exposure. In this study, we investigated whether NP‐6A4–induced AT2R activation could mitigate AngII‐induced abdominal aortic aneurism (AAA) using AngII‐treated Apoe−/− mice. Male Apoe−/− mice were infused with AngII (1 µg/kg/min) by implanting osmotic pumps subcutaneously for 28 days. A subset of mice was pre‐treated subcutaneously with NP‐6A4 (2.5 mg/kg/day) or vehicle for 14 days prior to AngII, and treatments were continued for 28 days. NP‐6A4 significantly reduced aortic stiffness of the abdominal aorta induced by AngII as determined by ultrasound functional analyses and histochemical analyses. NP‐6A4 also increased nitric oxide bioavailability in aortic tissues and suppressed AngII‐induced increases in monocyte chemotactic protein‐1, osteopontin and proteolytic activity of the aorta. However, NP‐6A4 did not affect maximal intraluminal aortic diameter or AAA incidences significantly. These data suggest that the effects of AT2R agonist on vascular pathologies are selective, affecting the aortic stiffness and proteolytic activity without affecting the size of AAA.

Preoperative dilated esophagus is associated with a high risk of intrathoracic anastomotic leakage for patients with esophageal cancer.

BackgroundThe association between the preoperative condition of the esophagus and anastomotic leakage has seldom been studied. We observed a dominant dilation of the esophagus under barium esophagography in some esophageal cancer patients. In consideration of the larger circular stapler are applied in colorectal surgery, we wonder if larger circular stapler should be applied in these patients to fit the larger esophagus. The larger size of the circular stapler also could decrease the incidence of anastomosis stricture. Thus, we made this study to explore if patients with a dilated esophagus were facing a higher risk of anastomotic leakage when applying the 25 mm circular stapler.MethodsA retrospective review of patients undergoing gastroesophageal intrathoracic anastomosis using a 25 mm circular stapler was performed. Patients with endoscopy or barium esophagography confirmed anastomotic leakage was assigned to leakage group (LG) while the left was enrolled in no leakage group (NLG). The measurement of the diameter of the esophagus was carried out at the level of 5 centimeters away from the upper margin of the tumor on esophagography.ResultsLG had a greater intraluminal mucosal phase diameter (IMPD) than NLG (P=0.010). The ROC curve indicated 1.79 cm as the cutoff value for IMPD. Patients with IMPD greater than 1.79 cm had a statistically significant higher rate of leakage. In the multivariate logistic regression analysis, dilated IMPD was proven to be a risk factor of 25 mm-circular-stapler anastomotic leakage.ConclusionsPatients with an IMPD over 1.79 mm are facing a higher risk of intrathoracic anastomosis leakage when applying the 25 mm circular stapler. Larger circular stapler or hand-sewn would be the better choice for these patients.

Measurement of Pulse Propagation Velocity, Distensibility and Strain in an Abdominal Aortic Aneurysm Mouse Model.

An abdominal aortic aneurysm (AAA) is defined as a localized dilation of the abdominal aorta that exceeds the maximal intraluminal diameter (MILD) by 1.5 times of its original size. Clinical and experimental studies have shown that small aneurysms may rupture, while a subpopulation of large aneurysms may remain stable. Thus, in addition to the measurement of intraluminal diameter of the aorta, knowledge of structural traits of the vessel wall may provide important information to assess the stability of the AAA. Aortic stiffening has recently emerged as a reliable tool to determine early changes in the vascular wall. Pulse propagation velocity (PPV) along with the distensibility and radial strain are highly useful ultrasound-based methods relevant for assessing aortic stiffness. The primary purpose of this protocol is to provide a comprehensive technique for the use of ultrasound imaging system to acquire images and analyze the structural and functional properties of the aorta as determined by MILD, PPV, distensibility and radial strain.

Assessment of intima-media thickness of the carotid artery and intraluminal diameter of the brachial artery as cardiovascular risk markers in Brazilian adolescents with overweight or obesity.

Background The intima-media thickness of the carotid artery (cIMT) and endothelial dysfunction are associated with cardiovascular (CV) disease. Objectives To evaluate the correlation between cIMT, brachial intraluminal diameter and flow-mediated vasodilation on the reactive hyperemia phase in adolescents with obesity with predictors of CV risk. Methods Seventy-three pubertal patients with overweight or obesity were evaluated (45 girls) with a mean (standard deviation [SD]) age of 12.9 (2.5) years. Patients underwent anthropometric measurements and had the lipid profile, oral glucose tolerance test (oGTT) and serum intercellular adhesion molecule-1 (sICAM-1) levels analyzed. The ratios of the waist circumference (WC)/height (WHtR) and triglycerides (TG)/high-density lipoprotein cholesterol (HDL-C), homeostatic model assessment of insulin resistance (HOMA-IR), the Matsuda index and insulin area under the curve (AUC) were calculated. All patients were evaluated for cIMT and arterial blood flow velocity of the brachial artery. Results 75.3% of the patients had high cIMT values. We found a positive correlation between WHtR and cIMT (r = 0.233; p = 0.050). There was a positive correlation between sICAM-1 and insulin AUC (r = 0.323; p = 0.012) and WHtR (r = 0.258; p = 0.047). Patients with abnormal arterial dilation had higher sICAM-1 values (p = 0.02) despite having smaller WHtR (p = 0.046). Conclusions These adolescents with obesity had high cIMT values. Insulin resistance was associated with sICAM-1. Endothelial dysfunction was positively correlated with sICAM-1. There is no consensus about what the best laboratorial approach to evaluate insulin resistance in adolescents is, and the cutoff values of each method are arbitrary. So, as we saw earlier, the association between anthropometric data (WHtR) and ultrasound findings could be useful to evaluate the CV risk of these adolescents with obesity, because of its practical, direct and low-cost value.

Normal ultrasonographic dimensions of the gallbladder and common bile duct in neonates

Background: Ultrasound (US) is the first choice of imaging in neonates presenting with persistent jaundice to exclude surgically correctable causes and differentiate obstructive from nonobstructive causes. Previous studies on normal dimensions of gallbladder (GB) and common bile duct (CBD) recruited adults and children spread across a wide age group. Aims: This study aimed to determine GB and CBD normal dimensions in a large homogeneous neonatal population as well as guide decision regarding pre-US fasting in neonates who require GB evaluation. Materials and Methods: Five hundred and twenty-eight healthy newborns were recruited between May 2009 and May 2011. The widest intraluminal anterior-posterior diameters of GB and CBD were measured. Neonatal age in days, sex, birth weight, weight and height, gestational age at delivery, and time interval since last feed recorded. Results: The mean age was 9.56 ± 7.66 days, and 50.6% were males. The mean CBD diameter was 1.16 ± 1.61 mm while the mean GB diameter was 4.42 ± 2.16 mm. GB and CBD were clearly seen and measurable in 297 (55.8%) neonates and 237 (44.38%) neonates, respectively. There was a significant correlation between CBD diameter and GB diameter (P = 0.04) but no correlation with any demographic parameter. GB visualization was not dependent on time interval from last feed. Conclusion: Mean neonatal values for CBD and GB were established, but neonates have a wider range of GB diameters compared with older children, so GB diameter may not be a reliable parameter for neonatal GB pathologies. GB visualization was not dependent on time interval from last feed; hence, a recent feed should not delay emergency scans, especially in ill neonates

Utilization of Intraparotid Segments of Superficial Temporal Vessels for Head and Scalp Free Flap Microanastomosis: A Clinical, Histological, and Cadaveric Study.

The superficial temporal vessels (STV) are an underutilized target for head and neck microvascular reconstruction. Most surgeons regard the dissection as difficult, unreliable, and the anastomosis prone to vasospasm. The intraparotid course of the STV may provide more reliable flow without accompanying morbidity. A retrospective review of patients who underwent head and scalp free flap reconstruction utilizing STV intraparotid segment was performed. Demographic factors such as intraoperative and postoperative complications are reported. Five bilateral cadaver heads were dissected to describe the relationship to the facial nerve. STV histology was performed on four of the cadavers, noting intraluminal diameter and vessel wall thickness. Thirty-nine patients underwent free flap reconstruction with anastomosis to intraparotid STVs. Defect etiology included tumor resection (71.8%), traumatic brain injury (10.3%), intracranial bleed (12.8%), and acute trauma (5.1%). Flaps transferred included anterolateral thigh (51.3%), latissimus (33.3%), thoracodorsal artery perforator (7.7%), radial forearm (2.8%), and vastus lateralis (5.1%). Two flaps (5.1%) required takeback for arterial thrombosis, with one incidence of total flap loss (2.8%). There were no instances of transient or permanent facial nerve damage nor sialocele. On cadaver dissection, three distinct vessel segments were identified. Segments 1 and 2 represented the STVs superior to the upper tragal border. Segment 3 (intraparotid segment) began at the upper tragal border and STVs enlarged with a targeted anastomosis point at an average of 16.3 mm medial and 4.5 mm inferior to the upper border of the tragus. The frontal branch coursed 11.7 mm inferior and 11.5 mm anterior to this point. On histology, the intraluminal diameter of segment 3 was significantly larger than segment 2 (1.2 vs. 0.9 mm, p = 0.007). Head and neck free flap reconstruction with microanastomosis to the intraparotid segment of STVs can be safely and reliably performed.

Precise measurement of coronary stenosis diameter with CCTA using CT number calibration.

Coronary x-ray computed tomography angiography (CCTA) continues to develop as a noninvasive method for the assessment of coronary vessel geometry and the identification of physiologically significant lesions. The uncertainty of quantitative lesion diameter measurement due to limited spatial resolution and vessel motion reduces the accuracy of CCTA diagnoses. In this paper, we introduce a new technique called computed tomography (CT)-number-Calibrated Diameter to improve the accuracy of the vessel and stenosis diameter measurements with CCTA. A calibration phantom containing cylindrical holes (diameters spanning from 0.8mm through 4.0mm) capturing the range of diameters found in human coronary vessels was three-dimensional printed. We also printed a human stenosis phantom with 17 tubular channels having the geometry of lesions derived from patient data. We acquired CT scans of the two phantoms with seven different imaging protocols. Calibration curves relating vessel intraluminal maximum voxel value (maximum CT number of a voxel, described in Hounsfield Units, HU) to true diameter, and full-width-at-half maximum (FWHM) to true diameter were constructed for each CCTA protocol. In addition, we acquired scans with a small constant motion (15mm/s) and used a motion correction reconstruction (Snapshot Freeze) algorithm to correct motion artifacts. We applied our technique to measure the lesion diameter in the 17 lesions in the stenosis phantom and compared the performance of CT-number-Calibrated Diameter to the ground truth diameter and a FWHM estimate. In all cases, vessel intraluminal maximum voxel value vs diameter was found to have a simple functional form based on the two-dimensional point spread function yielding a constant maximum voxel value region above a cutoff diameter, and a decreasing maximum voxel value vs decreasing diameter below a cutoff diameter. After normalization, focal spot size and reconstruction kernel were the principal determinants of cutoff diameter and the rate of maximum voxel value reduction vs decreasing diameter. The small constant motion had a significant effect on the CT number calibration; however, the motion-correction algorithm returned the maximum voxel value vs diameter curve to that of stationary vessels. The CT number Calibration technique showed better performance than FWHM estimation of diameter, yielding a high accuracy in the tested range (0.8mm through 2.5mm). We found a strong linear correlation between the smallest diameter in each of 17 lesions measured by CT-number-Calibrated Diameter (DC ) and ground truth diameter (Dgt ), (DC =0.951×Dgt +0.023mm, r=0.998 with a slope very close to 1.0 and intercept very close to 0mm. Computed tomography-number-Calibrated Diameter is an effective method to enhance the accuracy of the estimate of small vessel diameters and degree of coronary stenosis in CCTA.

Mechanical Properties of the Every Second Matters for Mothers-Uterine Balloon Tamponade (ESM-UBT) Device: In Vitro Tests.

Objective Postpartum hemorrhage (PPH) is the most common cause of maternal mortality and morbidity worldwide, most of which occurs in resource-poor settings. Placement of a uterine balloon may be life-saving in uncontrolled PPH. The Every Second Matters for Mothers-Uterine Balloon Tamponade (ESM-UBT) device is an ultra-low-cost uterine balloon designed for global access. The purpose of this study was to evaluate the mechanical properties of the ESM-UBT device. Study design Intraluminal pressures, diameters, and burst volumes of condom uterine balloons and Foley catheter balloons of ESM-UBT devices were measured in open air and inside uterus models. Condom uterine balloons were tested with uterus model sizes of 100, 250, and 500mL. The condom-catheter O-ring attachment tensile strength was also evaluated. Results All 28 samples of ESM-UBT condom uterine balloons maintained their integrity for at least 3 hours when subjected to pressures of 200 mm Hg or greater across each of the tested uterine volumes. No Foley catheter balloons burst after instillation of 30mL, O-rings withstood forces of 15.4 ± 2.1 N, and condom uterine balloons stretched to 35.8 ± 2.1 cm without loss of integrity. Conclusion The mechanical properties of the ESM-UBT device make it attractive for scale across resource-poor settings.