Vertebral artery dissection following intravascular catheter placement: a case report and review of the literature

Vertebral artery dissections (VAD) are known to occur as a result of mechanical manipulations of the cervical region, traumatic injury, iatrogenic injury and are also known to arise spontaneously. We report a case of vertebral artery dissection following vertebral artery cannulation during a central line placement and review the literature. The patient underwent intravascular catheter placement that subsequently demonstrated arterial blood. Duplex ultrasound and computed tomographic (CT) scan confirmed vertebral artery cannulation. The catheter was removed at the bedside with pressure, and a subsequent duplex ultrasound scan revealed a vertebral artery dissection. There were no neurological sequelae. The patient was successfully anticoagulated with warfarin but died from unrelated complications. This case report describes the rare iatrogenic event of VAD and reviews its etiology, diagnosis, complications, and management.

Noninfectious Saccular Abdominal Aortic Aneurysm

Saccular aortic aneurysms are eccentrically shaped and are commonly thought to be the consequence of infection of the aorta. However, saccular-type aneurysms can be found independent of any clinical or subclinical infection and can be associated with a penetrating aortic ulcer. Moreover, penetrating aortic ulcers have been described in the thoracic aorta, but there is a paucity of any documentation of this clinical and pathologic entity occurring in the abdominal aorta. The authors describe 2 cases of symptomatic, penetrating atherosclerotic ulcers of the abdominal aorta causing saccular, noninfectious abdominal aortic aneurysms.

Prolonged Mechanical Circumferential Stretch Induces Metabolic Changes in Rat Inferior Vena Cava

OBJECTIVE/BACKGROUND

Circumferential stretch on the vein wall has been suggested as a potential etiological factor in the development of varicose veins. However, the influence of vein wall stretch on vein metabolism has not yet been explored. The aim of this study was to investigate the effect of short and prolonged mechanical stretch on vein wall metabolism.

METHODS

Circular segments of inferior vena cava from male Sprague-Dawley rats were exposed to normal 0.5-g (nonstretched) or high 2-g (stretched) tension for short (4 h) or prolonged (18 h) duration (five vein segments per group). Contraction response to phenylephrine (10^-5 M) and KCl (96 mM) was elicited to observe the effect of circumferential stretch on vein function. The polar and organic metabolites in vein tissue were extracted using a bilayer extraction method. Aqueous and organic extracts were analyzed using nuclear magnetic resonance spectroscopy and ultra performance liquid chromatography coupled to mass spectrometry, respectively. Data acquired from both analytical platforms were analyzed using mathematical modeling.

RESULTS

Increased concentrations of valine (p = .02) and choline (p = .03) metabolites and triglyceride moieties (p = .03) were observed in veins stretched for 18 h compared with the nonstretched/18 h group.

DISCUSSION

Increased concentrations of branched chain amino acid valine and cell membrane constituent choline indicate increased muscle breakdown and increased metabolism of membrane phospholipids under stretch in an ex-vivo model. Increased intensities of triglyceride moieties in stretched vein segments for 18 h suggest that high pressure may induce an inflammatory response.

CONCLUSION

This study has shown that prolonged mechanical circumferential stretch (18 h) alters the metabolic profile of rat inferior vena cava.

Mitogen-Activated Protein Kinase Pathway Regulates Cell Proliferation in Venous Ulcer Fibroblasts

Venous ulcer fibroblasts have been demonstrated to have low growth rates in response to platelet-derived growth factor (PDGF). Mitogen-activated protein kinase (MAPK) is an important signal transduction mechanism that regulates growth, differentiation, and apoptosis in eukaryotic cells. PDGF binds PDGF receptors that activate a multitiered signaling cascade involving MAPK. We hypothesize that the growth regulation in venous ulcer fibroblasts is dependent on the MAPK extracellular signal-regulated kinase (ERK) pathway in the presence of PDGF. Fibroblasts (fb) were isolated from 8 patients with venous ulcers (w-fb) and the normal skin (n-fb) of the ipsilateral thigh via punch biopsies. Fb were plated at 1,500 cells/dish and treated with PDGF-AB (10 ng/mL) for 15 days. Growth rates were determined. Immunoblot analysis of MAPK ERK for n-fb and w-fb were analyzed. To determine if PDGF-stimulated w-fb and n-fb utilized the MAPK ERK pathway in a dependent manner, the upstream kinase MAPK kinase 1 (MEK 1) was inhibited by PD 98059. In addition, fb were treated with chronic venous ulcer wound fluid (WF) to study its effect on MAPK ERK. In the presence of PDGF, growth rates were substantially lower in w-fb than in n-fb, and MAPK was activated in 6/8 w-fb and in only 2/8 n-fb. Fibroblasts expressing MAPK had significantly reduced cell proliferation compared to fibroblasts not expressing MAPK (p = 0.023). PD 98059 significantly inhibited wfb and n-fb cell proliferation from basal level, which was reversible with addition of PDGF. In neonatal fibroblasts WF demonstrated inhibition of MAPK ERK over time and addition of PD98059 was not additive. This study suggests that the MAPK ERK pathway is important for cell proliferation in venous ulcer fibroblasts. In the presence of PDGF, fibroblasts with decreased growth rate express MAPK, and proliferation is further abrogated with addition of MEK 1 inhibitor, suggesting the importance of the MAPK ERK pathway regulating w-fb and nfb proliferation. Although the majority of w-fb activated the MAPK ERK pathway in the presence of PDGF, proliferation was significantly attenuated, indicating that other MAPK inhibitory pathways are competing. Venous ulcer wound fluid directly inhibits the MAPK ERK pathway, suggesting that the venous ulcer wound environment has negative trophic factors that effect fibroblasts proliferation and ulcer healing.

Chronic venous disease - Part II: Proteolytic biomarkers in wound healing

Venous leg ulcers (VLU) are characterized by sustained proteolytic microenvironment impairing the healing process. Wound fluid (WF) reflect the biomolecular activities occurring within the wound area; however, it is unclear if WF from different healing phases have different proteolytic profiles and how VLU microenvironment affects the wound healing mechanisms. We investigated the proteolytic network of WF from distinct VLU phases, and in WF- and LPS-stimulated THP-1 monocytes treated with glycosaminoglycan sulodexide, a well known therapeutic approach for VLU healing. WF were collected from patients with VLU during inflammatory (Infl) and granulating (Gran) phases. WF and THP-1 supernatants were analyzed for nine matrix metalloproteinases (MMP) and four tissue inhibitors of metalloproteinases (TIMP) by multiplex immunoassays. Our results demonstrated that: 1) WF from Infl VLU contained significantly increased concentrations of MMP-2, MMP-9, MMP-12, TIMP-1, and TIMP-2 compared to Gran WF; 2) WF from Gran VLU showed significantly increased levels of MMP-1, MMP-7, MMP-13, and TIMP-4 compared to Infl WF; 3) LPS- and WF-stimulation of THP-1 cells significantly increased the expression of several MMP compared to untreated cells; 4) Sulodexide treatment of both LPS- and WF-stimulated THP-1 significantly down-regulated the release of several MMPs. Our study provides evidence-based medicine during treatment of patients with VLU. WF from Infl and Gran VLU have different MMP and TIMP signatures, consistent with their clinical state. The modulation of proteolytic pathways in wound microenvironment by glycosaminoglycan sulodexide, provide insights for translating research into clinical practice during VLU therapy.

Pathophysiology of wound healing and alterations in venous leg ulcers-review

Venous leg ulcer (VLU) is one of the most common lower extremity ulcerated wound, and is a significant healthcare problem with implications that affect social, economic, and the well-being of a patient. VLU can have debilitating related problems which require weekly medical care and may take months to years to heal. The pathophysiology of VLU is complex, and healing is delayed in many patients due to a persistent inflammatory condition. Patient genetic and environmental factors predispose individuals to chronic venous diseases including VLU. Changes in shear stress affecting the glycocalyx are likely initiating events, leading to activation of adhesion molecules on endothelial cells, and leukocyte activation with attachment and migration into vein wall, microcirculation, and in the interstitial space. Multiple chemokines, cytokines, growth factors, proteases and matrix metalloproteinases are produced. The pathology of VLU involves an imbalance of inflammation, inflammatory modulators, oxidative stress, and proteinase activity. Understanding the cellular and biochemical events that lead to the progression of VLU is critical. With further understanding of inflammatory pathways and potential mechanisms, certain biomarkers could be revealed and studied as both involvement in the pathophysiology of VLU but also as therapeutic targets for VLU healing.

Impact of coexisting aneurysms on open revascularization for aortoiliac occlusive disease

OBJECTIVE

National data evaluating outcomes for occlusive abdominal aortic reconstructions are well described. The relative effect of operative indication as well as the presence of concomitant abdominal aortic aneurysm (AAA) on in-hospital mortality is not well defined.

METHODS

The Nationwide Inpatient Sample was queried to identify patients who underwent open aortic surgery (2003-2010). Indication for surgery was classified by International Classification of Diseases, Ninth Revision diagnostic codes to identify isolated occlusive indications as well as combined occlusive disease and AAA. Primary outcome was in-hospital mortality. Secondary outcomes were complications and discharge disposition.

RESULTS

Overall, 56,374 underwent aortic reconstruction, 48,591 for occlusive disease (86.2%) and 7783 for combined occlusive disease with AAA (13.8%). Intermittent claudication was the most common indication for intervention (60.9%), whereas 39.7% underwent intervention for critical limb ischemia (22.2% rest pain, 17.6% gangrene). Patients with intermittent claudication had more concomitant AAAs (17.3%) than did patients with critical limb ischemia (8.4%). The baseline characteristics for those with occlusive disease and combined occlusive with AAA disease were similar in terms of obesity (4.8% vs 4.2%; P = .27) and congestive heart failure (6.6% vs 6.3%; P = .65) but differed by age (62.2 years vs 68.4 years; P < .0001) and hypertension (65.4% vs 69.1%; P = .005). Patients with combined occlusive and AAA disease had higher mortality than those with occlusive disease alone (3.9% vs 2.7%; P = .01). On multivariable regression, factors associated with in-hospital mortality included gangrene with AAA compared with gangrene alone (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.6-4.7; P < .0002), age >65 years age (OR, 3.1; 95% CI, 2.4-4.1; P < .0001), renal failure (OR, 2.7; 95% CI, 1.9-3.8; P < .0001), and concurrent lower extremity revascularization (OR, 1.3; 95% CI, 1.1-1.7; P < .02).

CONCLUSIONS

Intermittent claudication or critical limb ischemia with concomitant AAA carries a higher mortality than intermittent claudication or critical limb ischemia alone, especially in older patients with gangrene requiring revascularization and renal insufficiency. Preoperative risk stratification strategies should focus on the indication for surgery as well as the presence of concomitant AAA.

Practice patterns of adjunctive therapy for venous leg ulcers

Objectives Venous leg ulcers (VLU) are the most severe clinical sequelae of venous reflux and post thrombotic syndrome. There is a consensus that ablation of refluxing vein segments and treatment of significant venous obstruction can heal VLUs. However, there is wide disparity in the use and choice of adjunctive therapies for VLUs. The purpose of this study was to assess these practice patterns among members of the American Venous Forum. Methods The AVF Research Committee conducted an online survey of its own members, which consisted of 16 questions designed to determine the specialty of physicians, location of treatment, treatment practices and reimbursement for treatment of VLUs Results The survey was distributed to 667 practitioners and a response rate of 18.6% was achieved. A majority of respondents (49.5%) were vascular specialists and the remaining were podiatrists, dermatologists, primary care doctors and others. It was found that 85.5% were from within the USA, while physicians from 14 other countries also responded. Most of the physicians (45%) provided adjunctive therapy at a private office setting and 58% treated less than 5 VLU patients per week. All respondents used some form of compression therapy as the primary mode of treatment for VLU. Multilayer compression therapy was the most common form of adjunctive therapy used (58.8%) and over 90% of physicians started additional modalities (biologics, negative pressure, hyperbaric oxygen and others) when VLUs failed compression therapy, with a majority (65%) waiting less than three months to start them. Medicare was the most common source of reimbursement (52.4%). Conclusions Physicians from multiple specialties treat VLU. While most physicians use compression therapy, there is wide variation in the selection and point of initiation for additional therapies once compression fails. There is a need for high-quality data to help establish guidelines for adjunctive treatment of VLUs and to disseminate them to physicians across multiple specialties to ensure standardized high-quality treatment of patients with VLUs.

Venous leg ulceration pathophysiology and evidence based treatment

Venous leg ulceration (VLU) is one of the most predominate medical disorders worldwide and in the western hemisphere it affects around 1.5% of the general population and up to 5% of the elderly population. Unfortunately, this trend will only increase given the growth of an aging population worldwide. Understanding its pathophysiology that begins with venous hemodynamic abnormalities and leads to inflammatory alterations with microcirculatory changes is critical to delivering effective curative therapy. As such, the main component to treatment is reversing the underlying venous hypertension and pro-inflammatory milieu using compression treatment along with various adjuvant therapies. Given its impact, a comprehensive multi-pronged approach to care, treatment and prevention is required to reverse the increasing trend that is observed worldwide.

Glycosaminoglycan sulodexide modulates inflammatory pathways in chronic venous disease

Inflammation represents an important epiphenomenon in the etiopathogenesis of chronic venous disease, a worldwide debilitating condition affecting millions of subjects. The pathophysiology of chronic venous disease (CVD) is based on the hemodynamic abnormalities in conjunction to alterations in cellular and extracellular matrix biocompounds. The endothelial dysfunction results from early perturbation in the endothelium linked to glycocalyx injury and promoted by inflammatory cells and mediators (such as matrix metalloproteinases and interleukins), which lead to progressive dilation of the vein resulting in chronic venous insufficiency. Activated leukocytes during the inflammatory process release enzymes, free radicals, chemokines and inflammatory cytokines in the vessel microenvironment, which are responsible for the changes of the venous wall and venous valve, reflux and venous hypertension, and the development/progression of tissue destruction and skin changes. Sulodexide, a highly purified mixture of glycosaminoglycans composed by 80% fast moving heparin and 20% of dermatan sulphate, exhibits anti-thrombotic and profibrinolytic properties, restoring also the essential endothelial glycocalyx. Glycosaminoglycan sulodexide has been also characterized to reduce the release of inflammatory cytokines/chemokines and to inhibit the matrix metalloproteinases-related proteolytic cascades, counteracting endothelial dysfunctions. The pleiotropic effects of sulodexide set the basis for a very promising agent in treating the spectrum of CVD.

Pathophysiology of chronic venous disease

Chronic venous disease (CVD) is a debilitating condition with a prevalence between 60-70%. The disease pathophysiology is complex and involves genetic susceptibility and environmental factors, with individuals developing visible telengiectasias, reticular veins, and varicose veins. Patient with significant lower extremity symptoms have pain, dermal irritation, swelling, skin changes, and are at risk of developing debilitating venous ulceration. The signature of CVD is an increase in venous pressure referred to as venous hypertension. The various symptoms presenting in CVD and the clinical signs that are observed indicate that there is inflammation, secondary to venous hypertension, and it leads to a number of inflammatory pathways that become activated. The endothelium and glycocalyx via specialized receptors are critical at sensing changes in shear stress, and expression of adhesion molecules allows the activation of leukocytes leading to endothelial attachment, diapedisis, and transmigration into the venous wall/valves resulting in venous wall injury and inflammatory cells in the interstitial tissues. There is a complex of cytokines, chemokines, growth factors, proteases and proteinases, produced by activated leukocytes, that are expressed and unbalanced resulting in an environment of persistent inflammation with the clinical changes that are commonly seen, consisting of varicose veins to more advanced presentations of skin changes and venous ulceration. The structural integrity of protein and the extracellular matrix is altered, enhancing the progressive events of CVD. Work focusing on metabolic changes, miRNA regulation, inflammatory modulation and the glycocalyx will further our knowledge in the pathophysiology of CVD, and provide answers critical to treatment and prevention.

Which dressings reduce inflammation and improve venous leg ulcer healing

Chronic venous leg ulcers (VLU) affect around 1% of the adult population in the Western world. The impact of VLU is both social and economic, with significant expenditures on active venous ulcers to provide medical treatment and eventual healing. At the core of VLU is venous hypertension which affects the venous macrocirculation. The changes incurred in venous hemodynamics leads to microcirculatory changes affecting the postcapillary venule and surrounding tissues. Inflammation by leukocytes affecting the venous endothelium, promotes a complex cascade and activation of adhesion molecules expression, chemokines and cytokines released, altered growth factor responses, and activation of protease (e.g. tPA) and proteinase (e.g. MMPs) activity that causes dysregulation and compromise of tissue integrity with eventual dermal damage and ulcer development. A critical component to treating VLU is correcting the abnormal venous hemodynamics and compression therapy. Unfortunately, VLU recurrence ranges between 30–70%, and other modalities in therapy along with compression are required. The goal for adjuvant products is to restore the balance from an inflammatory chronic wound to that of a reparative wound that will promote provisional matrix and epithelialization. There are many products on the market that can be used as adjuvant to compression therapy, but it must be recognized that there is a paucity of clinical trials that have evaluated the clinical effectiveness of specific products with clearly defined end points, and most importantly a healed VLU with a low recurrence rate. This review will discuss the fundamentals of VLU inflammation, and evaluate the available literature that may have benefit in reducing inflammation and lead to effective VLU healing.

Inflammation in chronic venous ulcers

Chronic venous ulcers (CVUs) occur in approximately 1% of the general population. Risk factors for chronic venous disease (CVD) include heredity, age, female sex and obesity. Although not restricted to the elderly, the prevalence of CVD, especially leg ulcers, increases with age.1 CVD has a considerable impact on health-care resources. It has been estimated that venous ulcers cause the loss of approximately two million working days and incur treatment costs of approximately $3 billion per year in the USA.2 Overall, CVD has been estimated to account for 1–3% of the total health-care budgets in countries with developed health-care systems.1 The pathophysiology of dermal abnormalities in CVU is reflective of a complex interplay that involves sustained venous hypertension, inflammation, changes in microcirculation, cytokine and matrix metalloproteinase (MMP) activation, resulting in altered cellular function and delayed wound healing.3,4