Gianfranco Varetto

Fractal parameters and vascular networks: facts & artifacts

BackgroundSeveral fractal and non-fractal parameters have been considered for the quantitative assessment of the vascular architecture, using a variety of test specimens and of computational tools. The fractal parameters have the advantage of being scale invariant, i.e. to be independent of the magnification and resolution of the images to be investigated, making easier the comparison among different setups and experiments.ResultsThe success of several commercial and/or free codes in computing the fractal parameters has been tested on well known exact models. Based on such a preliminary study, we selected the code Frac-lac in order to analyze images obtained by visualizing the angiogenetic process occurring in chick Chorio Allontoic Membranes (CAM), assumed to be paradigmatic of a realistic 2D vascular network. Among the parameters investigated, the fractal dimension Df proved to be the most robust estimator for CAM vascular networks. Moreover, only Df was able to discriminate between effective and elusive increases in vascularization after drug-induced angiogenic stimulations on CAMs.ConclusionThe fractal dimension Df is likely to be the most promising tool for monitoring the effectiveness of anti-angiogenic therapies in various clinical contexts.

A one-stage approach to the treatment of intravenous leiomyomatosis extending to the right heart

This report describes the case of a 60-year-old woman with a history of hysterectomy for myomas, totally asymptomatic, with incidental evidence of a pelvic intracaval mass extending to the right atrium. She underwent a staged procedure (sternothomic and abdominal) through a thoracolaparotomic approach in circulatory arrest and deep hypothermia. Using a one-stage surgical approach, we were able to withdraw one portion of the mass from the right atrium and another from the abdominal inferior vena cava, thus minimizing the risk of unexpected venous or atrial wall injury during surgical manipulation.

Ultrasound-activated decafluoropentane-cored and chitosan-shelled nanodroplets for oxygen delivery to hypoxic cutaneous tissues

Ultrasound (US)-activated perfluoropentane-cored oxygen-loaded nanobubbles (OLNBs) were recently proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature (e.g. diabetes-associated chronic wounds, anaerobic infections, cancer). Here we introduce a new platform of oxygen nanocarriers, constituted of 2H,3H-decafluoropentane (DFP) as core fluorocarbon and chitosan as shell polysaccharide, and available either in liquid or gel formulations. Such oxygen-loaded nanodroplets (OLNDs) display spherical morphology, ∼700 nm diameters, cationic surfaces, good oxygen carrying capacity (without singlet oxygen generation after sterilization by ultraviolet-C rays), and no toxic effects on human keratinocytes. In vitro, OLNDs are more effective in releasing oxygen to hypoxic environments than former OLNBs, either with or without complementary US administration (f = 1 MHz; P = 5 W). In vivo, sonication of topically applied OLNDs appears essential to allow significant and time-sustained oxygen release. Taken together, the present data suggest that US-activated chitosan-shelled/DFP-cored OLNDs might be innovative, suitable and cost-effective devices to treat several hypoxia-associated pathologies of the cutaneous tissues.

2H,3H-decafluoropentane-based nanodroplets: new perspectives for oxygen delivery to hypoxic cutaneous tissues.

Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues.

Use of Contrast-Enhanced Ultrasound in Carotid Atherosclerotic Disease: Limits and Perspectives

Contrast-enhanced ultrasound (CEUS) has recently become one of the most versatile and powerful diagnostic tools in vascular surgery. One of the most interesting fields of application of this technique is the study of the carotid atherosclerotic plaque vascularization and its correlation with neurological symptoms (transient ischemic attack, minor stroke, and major stroke) and with the characteristics of the “vulnerable plaque” (surface ulceration, hypoechoic plaques, intraplaque hemorrhage, thinner fibrous cap, and carotid plaque neovascularization at histopathological analysis of the sample after surgical removal). The purpose of this review is to collect all the original studies available in literature (24 studies with 1356 patients enrolled) and to discuss the state of the art, limits, and future perspectives of CEUS analysis. The results of this work confirm the reliability of this imaging study for the detection of plaques with high risk of embolization; however, a shared, user-friendly protocol of imaging analysis is not available yet. The definition of this operative protocol becomes mandatory in order to compare results from different centers and to validate a cerebrovascular risk stratification of the carotid atherosclerotic lesions evaluated with CEUS.

Popliteal Artery Entrapment Syndrome in a Young Girl: Case Report of a Rare Finding

The popliteal artery (PA) entrapment syndrome, a rare cause of arterial thrombosis, is most often encountered in young male athletes. Here, we report a very unusual case of PA entrapment syndrome in a 14-year-old girl who presented with a 1-month history of calf claudication to our observation facility. Diagnostic work-up revealed obesity, sedentary lifestyle, and an aberrant accessory slip of the medial head of gastrocnemius around the PA. Arterial echo color Doppler ultrasonography and computed tomographic angiography studies were performed. Surgical treatment involved revascularization with resection of the medial head of gastrocnemius, the cause of the arterial entrapment, and enlargement angioplasty using an autologous saphenous vein patch, in combination with antiplatelet therapy, resulting in restitution ad integrum of the affected limb and, finally, an improved quality of life of the patient. This case underscores the importance of clinical suspicion, diagnosis, and treatment of lower-limb claudication in very young patients presenting with unusual symptoms. If missed, the condition may evolve dramatically. Prompt diagnosis and surgical treatment are key to complete recovery and the prevention of irreversible complications that may result in limb loss.

Preoperative and Postoperative Evaluation of New Double Mesh Carotid Stents with Contrast-Enhanced Ultrasound and Diffusion-Weighted Imaging

In this case series, we selected 4 patients with asymptomatic severe carotid stenosis due to unstable plaques, which were identified with contrast-enhanced ultrasound. These patients underwent carotid stenting with a new generation double mesh stent. Diffusion-weighted magnetic resonance imaging (DW-MRI) was executed before and after the procedure to detect early cerebral microembolizations. No early neurological complications occurred nor cerebral microembolizations were detected at DW-MRI. New double mesh carotid stents appear to be a safe option also in asymptomatic patients with unstable plaques at high risk for surgery.

Primary Aortoenteric Fistula of a Saccular Aneurysm: Case Study and Literature Review

Primary aortoenteric fistula is a direct communication between the aorta and intestinal lumen and it represents a rare but potentially lethal complication of an abdominal aortic aneurysm. However, it may occur less frequently in a naive non-aneurysmatic aorta. Diagnosis is often difficult and delayed in most cases, unless there is a high level of clinical awareness. Urgent surgery is still the recommended treatment. We describe the case of primary aortoenteric fistula of a saccular aneurysm. A 55-year-old woman was referred to our center with hematemesis, melena, and severe anemia who was dignosed previously with unknown saccular abdominal aneurysm.

Successful Management with 2 Overlapping Bare Stents for Post–Carotid Endarterectomy Carotid Pseudoaneurysm Secondary to Carotid Shunt

Pseudoaneurysms are a rare complication of carotid endarterectomy. We successfully excluded with 2 overlapping bare stents a distal carotid artery pseudoaneurysm very likely induced by a Pruitt-Inahara shunt 2 months after carotid endarterectomy.

Rupture of giant superficial femoral artery aneurysm in a leukemic patient submitted to chemotherapy.

The superficial femoral artery (SFA) is a relatively rare location for lower limb aneurysmatic disease. In the literature, this disease is described an association between a relatively high growth rate and/or the rupture of aneurysms and chemotherapeutic agents. We report a case of the rupture of a giant SFA aneurysm in a patient during chemotherapy for acute lymphatic leukemia.