Preservation of deep epigastric perforators during anterior component separation technique (ACST) results in equivalent wound complications compared to transversus abdominis release (TAR).

PURPOSE: The use of component separation results in myofascial release and increased rates of fascial closure in abdominal wall reconstruction(AWR). These complex dissections have been associated with increased rates of wound complications with anterior component separation having the greatest wound morbidity. The aim of this paper was to compare the wound complication rate between perforator sparing anterior component separation(PS-ACST) and transversus abdominus release(TAR). METHODS: Patients were identified from a prospective, single institution hernia center database who underwent PS-ACST and TAR from 2015 to 2021. The primary outcome was wound complication rate. Standard statistical methods were used, univariate analysis and multivariable logistic regression were performed. RESULTS: A total of 172 patients met criteria, 39 had PS-ACST and 133 had TAR performed. The PS-ACST and TAR groups were similar in terms of diabetes (15.4% vs 28.6%, p = 0.097), but the PS-ACST group had a greater percentage of smokers (46.2% vs 14.3%, p < 0.001). The PS-ACST group had a larger hernia defect size (375.2 ± 156.7 vs 234.4 ± 126.9cm2, p < 0.001) and more patients who underwent preoperative Botulinum toxin A (BTA) injections (43.6% vs 6.0%, p < 0.001). The overall wound complication rate was not significantly different (23.1% vs 36.1%, p = 0.129) nor was the mesh infection rate (0% vs 1.6%, p = 0.438). Using logistic regression, none of the factors that were significantly different in the univariate analysis were associated with wound complication rate (all p > 0.05). CONCLUSION: PS-ACST and TAR are comparable in terms of wound complication rates. PS-ACST can be used for large hernia defects and promote fascial closure with low overall wound morbidity and perioperative complications.

Change of Vertebral Left Atrial Size in Dogs With Preclinical Myxomatous Mitral Valve Disease Prior to the Onset of Congestive Heart Failure.

INTRODUCTION/OBJECTIVES: It has been proposed that vertebral left atrial size (VLAS) on thoracic radiographs can be used to assess the left atrial enlargement in dogs with myxomatous mitral valve disease (MMVD). However, it remains unclear whether VLAS can be used to distinguish dogs between pre-clinical MMVD that are at a greater risk of developing congestive heart failure (CHF) from those at a lower risk. We investigated this possibility. ANIMALS, MATERIALS AND METHODS: Forty-one dogs with MMVD were retrospectively classified into one of two groups, a group that developed CHF (group CHF, n = 17) or remained CHF-free (group no-CHF, n = 24). The value of vertebral heart scale (VHS) and VLAS at three time-points, change in VHS and VLAS at a specific time interval (ΔVHS, ΔVLAS) and rate of change in the values per month (ΔVHS/month, ΔVLAS/month) were compared. RESULTS: At the first visit, there were no significant differences in VLAS between the groups. At the median of 105 (interquartile ranges 83-155) days prior to the onset of CHF (group CHF) or the last visit (group no-CHF), VLAS was significantly higher in group CHF (mean, 2.9; standard deviation ± 0.4) than in group no-CHF (2.6 ± 0.3) (p = 0.028). ΔVLAS/month (area under the curve, 0.91; p<0.001) showed high diagnostic accuracy in distinguishing which dogs would develop CHF within 180 days and which would not. CONCLUSIONS: VLAS and ΔVLAS/month in dogs with pre-clinical MMVD may be useful to identify dogs at risk of developing CHF within the next 180 days.

Haemodynamic flow conditions at the initiation of high-shear platelet aggregation: a combined in vitro and cellular in silico study.

The influence of the flow environment on platelet aggregation is not fully understood in high-shear thrombosis. The objective of this study is to investigate the role of a high shear rate in initial platelet aggregation. The haemodynamic conditions in a microfluidic device are studied using cell-based blood flow simulations. The results are compared with in vitro platelet aggregation experiments performed with porcine whole blood (WB) and platelet-rich-plasma (PRP). We studied whether the cell-depleted layer in combination with high shear and high platelet flux can account for the distribution of platelet aggregates. High platelet fluxes at the wall were found in silico. In WB, the platelet flux was about twice as high as in PRP. Additionally, initial platelet aggregation and occlusion were observed in vitro in the stenotic region. In PRP, the position of the occlusive thrombus was located more downstream than in WB. Furthermore, the shear rates and stresses in cell-based and continuum simulations were studied. We found that a continuum simulation is a good approximation for PRP. For WB, it cannot predict the correct values near the wall.

Conversional Weight Loss Surgery: an Australian Experience of Converting Laparoscopic Adjustable Gastric Bands to Laparoscopic Sleeve Gastrectomy.

BACKGROUND: Bariatric surgery is the most effective treatment for severe obesity, capable of producing more than 50% excess weight loss at 10-year follow-up (James Clin Dermatol 1; 22:276-80; O'Brien Br J Surg 2; 102:611-17; Buchwald et al. Metab Syndr 3; 347-56). The success of bariatric surgery extends far beyond weight loss, with up to 80-90% of patients having improvement or resolution of many of their weight-related co-morbidities including type II diabetes mellitus and hypertension (Puzziferri et al. JAMA 4; 312:934-42; Buchwald et al. Am J Med 5; 122:248-56). However, there is a paucity of data regarding conversional bariatric surgery. OBJECTIVE: This study aims to explore the efficacy, safety and feasibility of conversional surgery. SETTING: This study represents the largest Australasian series focusing on conversional bariatric surgery. The study was conducted in the Norwest Private Hospital and Hospital for Specialist Surgery (HSS), both private Hospitals in Sydney, Australia. METHODS: Data was collected prospectively at regular intervals for more than 12 months from 1 January 2012 to 1st November 2015 for all patients requiring a laparoscopic sleeve gastrectomy (LSG) as secondary procedure after prior laparoscopic adjustable gastric band (LAGB). Excess weight loss (EWL), percentage total body weight loss (TWL) and excess BMI loss (EBMIL) as well as any complications were recorded. RESULTS: There were low rates of morbidity (1.1%) and no mortality at 12-month follow-up. Satisfactory EWL of 60% (95% CI: 56.6-63.4%), EBMIL of 60.1% (95% CI: 48.8-71.4%) and 16% TWL was achieved at 12-month follow-up. CONCLUSION: We therefore conclude that sleeve gastrectomy is a safe and valid option for conversional bariatric surgery following LAGB.

A study on the effects of covered stents on tissue prolapse.

Polyvinyl alcohol (PVA) cryogel covered stents may reduce complications from thrombosis and restenosis by decreasing tissue prolapse. Finite element analysis was employed to evaluate the effects of PVA cryogel layers of varying thickness on tissue prolapse and artery wall stress for two common stent geometries and two vessel diameters. Additionally, several PVA cryogel covered stents were fabricated and imaged with an environmental scanning electron microscope. Finite element results showed that covered stents reduced tissue prolapse up to 13% and artery wall stress up to 29% with the size of the reduction depending on the stent geometry, vessel diameter, and PVA cryogel layer thickness. Environmental scanning electron microscope images of expanded covered stents showed the PVA cryogel to completely cover the area between struts without gaps or tears. Overall, this work provides both computational and experimental evidence for the use of PVA cryogels in covered stents.

Rapid platelet accumulation leading to thrombotic occlusion.

Platelet thrombosis under arterial conditions remains a large clinical problem. Previous in vitro experiments have concentrated on early adherence without thrombotic occlusion. We have developed a controllable hemodynamic system that creates intravascular thrombosis to occlusion. Lightly heparinized (3.5 USP units/mL), whole, porcine blood is perfused through a 1.5 mm inner diameter, tubular, collagen-coated stenosis. The microscopic growth of thrombus is optically recorded using a high resolution CCD camera. Occlusive thrombus is examined using microcomputed tomography and histology. Thrombus consistently formed in the throat of the stenosis where wall shear rates were greatest. Rapid platelet accumulation (RPA) reached rates as high as 13.7 µm(3 )µm(-2) min(-1). Total occlusion of flow occurred after 17 ± 2.6 min (n = 6). The average thrombus volume accumulation of 7.8 ± 3.5 µm(3) µm(2) min(-1) occurred under very high wall shear rates exceeding 100,000 s(-1). Significant volumes of thrombus did not form until 7.6 ± 3.6 min after the onset of flow, a delay consistent with activation of adherent mural platelets. Platelets did not accumulate with large volume for normal wall shear rates <2000 s(-1). Very high wall shear rates stimulate the capture of millions of circulating platelets with exposure times <2 ms in an arterial stenosis.

Augmentation of bone tunnel healing in anterior cruciate ligament grafts: application of calcium phosphates and other materials.

Bone tunnel healing is an important consideration after anterior cruciate ligament (ACL) replacement surgery. Recently, a variety of materials have been proposed for improving this healing process, including autologous bone tissue, cells, artificial proteins, and calcium salts. Amongst these materials are calcium phosphates (CaPs), which are known for their biocompatibility and are widely commercially available. As with the majority of the materials investigated, CaPs have been shown to advance the healing of bone tunnel tissue in animal studies. Mechanical testing shows fixation strengths to be improved, particularly by the application of CaP-based cement in the bone tunnel. Significantly, CaP-based cements have been shown to produce improvements comparable to those induced by potentially more complex treatments such as biologics (including fibronectin and chitin) and cultured cells. Further investigation of CaP-based treatment in the bone tunnels during ACL replacement is therefore warranted in order to establish what improvements in healing and resulting clinical benefits may be achieved through its application.

The calcium ionophore A23187 induces endothelium-dependent contractions in femoral arteries from rats with streptozotocin-induced diabetes.

BACKGROUND AND PURPOSE: To study the importance of endothelium-derived contracting factors (EDCFs) in arteries of rats with type I diabetes. EXPERIMENTAL APPROACH: Rat femoral arteries were collected four or twelve weeks after induction of diabetes with streptozotocin. Rings, with or without endothelium, were suspended in organ chambers for isometric tension measurement. COX protein levels were determined by Western blotting. KEY RESULTS: Four weeks after the injection of streptozotocin, the endothelium-dependent relaxations (during contractions to phenylephrine) to A23817 were attenuated, but the endothelium-dependent contractions (quiescent preparations) to the ionophore were augmented. Indomethacin and S18886 prevented the endothelium-dependent contractions, while dazoxiben reduced them in rings from streptozotocin-treated rats, suggesting that thromboxane A2, activating TP- receptors, is involved. Twelve weeks after the injection of streptozotocin, the changes in endothelium-dependent relaxations and contractions to A23187 were even more noticeable. The protein expression of COX-1 was increased in femoral arteries of the diabetic rats. Valeryl salicylate and SC560 inhibited the contractions, suggesting that the EDCFs are produced by COX-1. At that time, a combination of S18886 with EP1-blockers was required to abolish the contractions, suggesting that the EDCFs involved act at both TP- and EP-receptors. Rings without endothelium from streptozotocin-treated rats exhibited a reduced maximal contraction to potassium chloride and U46619, combined with hyper-responsiveness to the latter, suggesting that more prolonged diabetes also alters the responsiveness of vascular smooth muscle. CONCLUSION AND IMPLICATIONS: The production of EDCFs is progressively increased in the course of type I diabetes. Eventually, the disease also damages vascular smooth muscle.

Protein Z, protein S levels are lower in patients with thrombophilia and subsequent pregnancy complications.

OBJECTIVE: We posit that low levels of protein S (PS) and protein Z (PZ) contribute to adverse pregnancy outcome (APO). PATIENTS: We evaluated 103 women with subsequent normal pregnancy outcome (NPO), 106 women with APO, and 20 women with thrombophilia (TP). METHODS: We compared first trimester (1st TRI) PZ levels in 103 women with NPO, 106 women with APO, and in 20 women with TP. We compared plasma levels of PZ and free PS antigen during the second (2nd TRI) and third trimesters (3rd TRI) of pregnancy in 51 women with APO and 51 matched women with NPO. RESULTS: The mean 1st TRI PZ level was significantly lower among patients with APO, compared to pregnant controls (1.81 +/- 0.7 vs. 2.21 +/- 0.8 microg mL(-1), respectively, P < 0.001). Of patients with known TP, those with APO had a tendency for lower mean PZ levels compared to those TP women with NPO (1.5 +/- 0.6 vs. 2.3 +/- 0.9 microg mL(-1), respectively, P < 0.0631). There was a significant decrease in the PZ levels in patients with APO compared to NPO (2nd TRI 1.5 +/- 0.4 vs. 2.0 +/- 0.5 microg mL(-1), P < 0.0001; and 3rd TRI 1.6 +/- 0.5 vs. 1.9 +/- 0.5 microg mL(-1), P < 0.0002). Protein S levels were significantly lower in the 2nd and 3rd TRIs among patients with APO compared to patients with NPO (2nd TRI 34.4 +/- 11.8% vs. 38.9 +/- 10.3%, P < 0.05, respectively; and 3rd TRI 27.5 +/- 8.4 vs. 31.2 +/- 7.4, P < 0.025, respectively). CONCLUSIONS: We posit that decreased PZ and PS levels are additional risk factors for APO.

The use of coagulation activation markers (soluble fibrin polymer, TpP, prothrombin fragment 1.2, thrombin-antithrombin, and D-dimer) in the assessment of hypercoagulability in patients with inherited and acquired prothrombotic disorders.

A total of 260 consecutive patients, referred for hypercoagulable assessment, was included in this study. Four coagulation activation markers were utilized to assess these patients [enzyme-linked immunosorbent assays for soluble fibrin polymer (TpP), prothrombin fragment 1.2, thrombin-antithrombin complex, and D-dimer]. The mean levels of the activation markers directly correlated with the number of hypercoagulable abnormalities. The percentage of patients with increased TpP levels for each group was lower than the other activation markers. The findings indicate that activation markers reflect the number of underlying thrombophilic abnormalities. Our data suggest that there is a utility in performing a panel of coagulation activation markers to assess the thrombotic risk. The measurement of soluble fibrin polymer may be more reflective of an impending vascular event.

Quantitative prediction of improvement in cardiac function after revascularization with MR imaging and modeling: initial results.

PURPOSE: To evaluate a model that can be used quantitatively to predict changes in postrevascularization left ventricular function based on classification of myocardial tissue as hibernating, scarred, or normal with cine magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eleven patients with chronic left ventricular dysfunction were studied before and after revascularization with cine MR imaging. Regional myocardial contractility and wall thickness were used in the model to predict postrevascularization ejection fraction (EF). The actual EF from the postrevascularization MR images was compared with the EF from the prerevascularization images predicted with the model by using regression analysis and Bland-Altman analysis. RESULTS: Correlation between the actual EF after revascularization and the EF predicted by using the model yielded an R value of 0.98, with a standard error of 1.3 EF percentage points. Predicting changes in function in a myocardial segment was less successful because only 55% of segments classified as hibernating actually improved resting function after revascularization. In nonimproved segments, 78% were either adjacent to infarcted segments or had nontransmural wall thinning. CONCLUSION: A simple mathematical model combined with functional information provided by MR imaging was used to predict improvements in global EF resulting from revascularization.

Thrombophilia and pregnancy: review of the literature and some original data.

The association of thrombophilia with pregnancy complications has received increasing attention. It is now apparent that thrombophilia is responsible for a large number of the serious complications of pregnancy such as venous thrombosis, pulmonary embolism, fetal loss, pregnancy loss, intrauterine fetal demise, and preeclampsia. The inherited thrombophilia abnormalities, factor V Leiden mutation, prothrombin gene mutation 20210A, and antithrombin III, protein C, and protein S deficiency, and the acquired disorders, the anticardiolipin syndrome and lupus inhibitor, are responsible for a large share of the incidences of premature termination of pregnancy and many of the above complications. The normal physiology of pregnancy may be prothrombotic, with evidence for increased markers of activated coagulation and coagulation factors. There is a decrease in protein S and resistance to activated protein C occurs in a significant number of pregnancies in the absence of the factor V Leiden mutation. In the following article, we review some of the major studies that have correlated the thrombophilia and other acquired disorders that adversely impact pregnancies.

Contractile responses in arteries subjected to hypertensive pressure in seven-day organ culture.

Early stage changes in hypertensive arteries have a significant effect on the long-term adaptation of the arteries. Compared to the long-term adaptation, little is known about the early dimensional and functional changes in hypertensive arteries in the first few days of hypertension. To study the early stage changes in hypertensive arteries, porcine common carotid arteries were cultured for seven days in a simplified ex vivo artery organ culture system with pulsatile flow under hypertensive (200+/-30 mm Hg) or normotensive (100+/-20 mm Hg) pressure conditions while maintaining a physiological mean wall shear stress of 15 dyn/cm2. Vessel viability was demonstrated by contractile diameter responses to norepinephrine (NE), carbachol (CCh), and sodium nitroprusside (SNP) as well as staining for mitochondrial activity and cell apoptosis/necrosis. The results show that arteries demonstrated strong contractile responses to NE, CCh, and SNP, basal tone, and viable mitochondria in the organ culture system for seven days. Hypertensive arteries demonstrated a stronger contractile response than normotensive arteries (p<0.05). Diameter enlargement was observed in hypertensive arteries as compared to arteries cultured under normotensive conditions. In conclusion, the pulsatile culture system can maintain arteries viable with active vasomotion tone for up to seven days. Hypertensive pressure causes arterial adaptation by significantly increasing arterial diameter and contractile response within the first seven days.