[Long-term results of surgical treatment of the extracranial arteries aneurysm]

Aneurysms of extracranial arteries are sufficiently rare pathology in the extracranial arteries surgery. The authors aimed to research the frequency of occurrence of the extracranial arteries aneurysm, reasons of the onset, the localization, clinical manifestations and surgical treatment strategy. A retrospective study presents 10 cases of the extracranial arteries aneurysm for the last 5 years. A presence of aneurysmatic dilatation of extra-cranial arteries was detected according to the data of ultrasonic duplex scanning (UDS) and patients were directed to the hospital. The UDS was carried out as a routine procedure because of the presence of earlier acute stroke or the transitory ischemic attack. All the patients were carefully examined. A computed tomography and the recurring UDS were performed and the neurologic status of patients was estimated. An indication to surgical treatment was an increase of the internal carotid artery diameter and the common carotid artery more than 50% or equal to it. The presence of the local saccular aneurysm was one of the reasons. Surgical treatment strategy was determined by the anatomic position and possibilities for the reconstruction. The results of given operations showed, that the surgical treatment strategy should be recommended and could be fully justified in this pathology.

The multilayer flow modulator stent for the treatment of arterial aneurysms

AIM

The purpose of this manuscript was to: 1) report our experience with the Multilayer Flow Modulator (MFM) for the treatment of peripheral, visceral and aortic aneurysms; 2) review the published literature regarding the outcomes of patients treated with the MFM; and 3) develop initial treatment guidelines regarding the MFM.

METHODS

We reviewed our clinical experience with the MFM in 58 high surgical risk patients. Thirty-one peripheral (PAAs), 9 visceral (VAAs) and 18 aortic aneurysms (10 thoracoabdominal [TAAA]; 8 abdominal) were treated. In addition, the PubMed database through April 2013, along with relevant websites and scientific presentations at international meetings, were quered regarding the MFM. Seventeen articles and 3 presentations were identified. Data regarding 178 patients treated with the MFM were included for analysis including 57 PAAs, 31 VAAs and 90 complex degenerative aortic lesions. Outcomes including technical success, 30-day mortality, endoleak rate and aneurysm-related survival were studied.

RESULTS

In our experience, there were 47 males and the mean age was 62 years (16-80). In patients with PAAs and VAAs, technical success with the MFM was 100%. At 30 days, there were no deaths. Initial MFM patency was 97.5% (39/40) with patency of the thrombosed MFM successfully restored. Longer-term follow-up (mean 16 ± 8 months) demonstrated progressive thrombosis and shrinkage of the aneurysm sacs and all side-branches were patent. In patients with aortic aneurysms, technical success was 100%, with no complications and no deaths at 30 days. Longer-term follow-up (8 ± 7 months) demonstrated aneurysm-related survival of 100%, all-cause survival of 83.3%, intervention-free survival of 100% and 100% patency of the side branches. The longest duration for aneurysm sac thrombosis was 18 months. A significant mean diameter reduction was observed at 6 months (17.3 mm for the transversal maximal diameter and 13.83 mm for the antero-posterior diameter) in the TAAA group. In the literature review, there was 100% technical success and a 97.7% 30-day survival rate in patients with PAAs and VAAs treated with the MFM. In follow-up (range 5-26 months), there were no aneurysm-related deaths or aneurysm ruptures and the overall survival was 95.5%. Complete aneurysm exclusion was observed in 94.3% of the patients with significant aneurysm shrinkage in 83% of the patients. Nine (10%) MFMs occluded with most occlusions resulting from pre-existing conditions. Patency of 5 occluded MFMs were restored and 4 occluded MFMs were not treated and were asymptomatic. All covered side branches were patent except in a patient with thrombophilia who also had an occluded MFM. The treatment of complex aortic degenerative lesions with MFM demonstrates a 95.5% 30-day survival with 2 aneurysm ruptures for contrindicated use (previously ruptured aneurysm; mycotic aneurysm). Over the follow-up (range 3-28 months), all-cause survival was 87.8% and aneurysm-related survival was 96.7% (1 late rupture due to a type 1 endoleak). Side branches were patent for 97.7% of the treated cases and a 13.3% endoleak rate was reported. There were no neurological, renal or respiratory complications. Complete exclusion and size stability were achieved for most of the cases.

CONCLUSION

Clinical experience with the MFM is increasing. The MFM has been used to treat many types of aneurysms including peripheral, visceral and aortic. Early results suggest that use of the MFM can help prevent aneurysm-related mortalities while maintining branch vessel patency. Additional study and investigation is needed.

Recanalization of thrombosed arteriovenous fistulas for hemodialysis by minimal venotomy

The present work describes the preliminary results of a new method of minimally invasive thrombectomy in the treatment of thrombosed arteriovenous fistula (AVF) with dilated aneurysm. Data from 25 patients who were treated with this minimal venotomy technique were retrospectively reviewed. The minimal venotomy was made on the dilated fistula, and thrombectomy was performed with forceps and Fogarty catheters through the venotomy site. Technical and clinical success was achieved in all 25 patients. There were two major and two minor complications (8% each). The two major complications consisted of bleeding at the venotomy site after early suture removal.

Hemodynamic Changes Caused by Flow Diverters in Rabbit Aneurysm Models: Comparison of Virtual and Realistic FD Deployments Based on Micro-CT Reconstruction

Adjusting hemodynamics via flow diverter (FD) implantation is emerging as a novel method of treating cerebral aneurysms. However, most previous FD-related hemodynamic studies were based on virtual FD deployment, which may produce different hemodynamic outcomes than realistic (in vivo) FD deployment. We compared hemodynamics between virtual FD and realistic FD deployments in rabbit aneurysm models using computational fluid dynamics (CFD) simulations. FDs were implanted for aneurysms in 14 rabbits. Vascular models based on rabbit-specific angiograms were reconstructed for CFD studies. Real FD configurations were reconstructed based on micro-CT scans after sacrifice, while virtual FD configurations were constructed with SolidWorks software. Hemodynamic parameters before and after FD deployment were analyzed. According to the metal coverage (MC) of implanted FDs calculated based on micro-CT reconstruction, 14 rabbits were divided into two groups (A, MC >35%; B, MC <35%). Normalized mean wall shear stress (WSS), relative residence time (RRT), inflow velocity, and inflow volume in Group A were significantly different (P<0.05) from virtual FD deployment, but pressure was not (P>0.05). The normalized mean WSS in Group A after realistic FD implantation was significantly lower than that of Group B. All parameters in Group B exhibited no significant difference between realistic and virtual FDs. This study confirmed MC-correlated differences in hemodynamic parameters between realistic and virtual FD deployment.

Multilayer stents, a new progress in the endovascular treatment of aneurysms

OBJECTIVE

To review the recent progress of multilayer stents in treating arterial aneurysms and to draw an initial conclusion about its paradigm.

DATA SOURCES

PubMed database and ELSEVIER database were searched with the keywords "cardiatis" or "multilayer stent" for relevant articles from January 2008 to September 2012. Relevant websites (provided by Cardiatis) were also involved in the review process.

STUDY SELECTION

Well-controlled, relatively large-scale, retrospective studies as well as meaningful individual cases were all selected as materials.

RESULTS

A total of 23 articles were involved in this review. The newly introduced Cardiatis multilayer stent aims at creating an active flow-modulating barrier between normal blood flow and aneurismal sac, which can induce thrombosis within aneurismal sac and preserve collateral circulation at the same time. Currently, it has been applied for complicated aneurysms located in different segments of the arterial system.

CONCLUSION

This new concept of multilayer uncovered stent offers a promising alterative in the treatment of arterial aneurysms. However, a further large-scale clinical and hemodynamic study is required to evaluate the long-term effects.

[Hybrid operation for a posttraumatic saccular aneurysm of the aortic arch]

The article deals with a case report of successful hybrid surgical treatment of a patient presenting with a posttraumatic large false saccular aneurysm of the aortic arch with mediastinal displacement and compression of the left recurrent laryngeal nerve and trachea. The patient was subjected to a hybrid operation, i. e., bypass grafting of the brachiocephalic trunk and the left common carotid artery with a bifurcation prosthesis from the ascending aorta through sternotomy, carotid-vertebral and carotid-subclavian bypass grafting on the left in a combination with endoprosthetic repair of the aortic arch with the stent graft Valiant Thoracic 40 × 224 mm (VAMF 4040c200TE) manufactured by the Medtronic Company. The postoperative period was uneventful followed by rather rapid rehabilitation of the patient. One month after the operation, the clinical state improved considerably. His voice restored virtually completely, and breathlessness disappeared. According to the findings of MSCT angiography, the aneurysmatic cavity is thrombosed, with the stent graft showing no evidence of either dislocation or endoleak. The bifurcation bypass graft is functioning. According to the data of duplex scanning, the anastomoses established on the neck are patent.

A case of extrinsic chronic cerebrospinal venous insufficiency in a patient with multiple sclerosis

We aim to present a very rare case of chronic cerebrospinal venous insufficiency due to both brachiocephalic vein obstruction by aberrant right subclavian artery and internal jugular vein distal compression by first cervical vertebra transverse process, demonstrated by multislice computerized tomography in a patient with multiple sclerosis.

Effect of saccular aneurysm and parent artery morphology on hemodynamics of cerebral bifurcation aneurysms

Morphological descriptors of aneurysms have been used to assess aneurysm rupture. This study investigated the relation between the morphological parameters and the flow related parameter of energy loss (EL). Four size indices and one shape index were assessed in idealized middle cerebral artery models with various aneurysm morphologies. Four patient-specific aneurysms (2 ruptured, 2 unruptured) were virtually manipulated by removing the aneurysms from their parent arteries and merging them with the idealized bifurcation models. EL was calculated from the energy difference between inflow and outflow. The results indicate that among size indices, EL is mostly dependent on bottleneck factor and less dependent on the aspect ratio. Results also showed that there is a direct relationship between nonsphericity index (NSI) and EL in manipulated models. No specific correlation was found between EL and NSI in patient-specific models.

[Endografting of a true aneurysm of the internal carotid artery]

Aneurysms of the internal carotid artery are a rarely encountered nosological entity, with only sporadic clinical cases being reported in both Russian and foreign literature. In the majority of instances, this pathology is removed by means of prosthetic repair of the internal carotid artery. However, recent trends are toward increased use of endovascular endografting. Described in the article is a case of an internal carotid artery aneurysm successfully treated by a self-opening stent graft.

Can aspect ratio be used to categorize intra-aneurysmal hemodynamics?--A study of elastase induced aneurysms in rabbit

Clinical studies suggest that aneurysm aspect ratio (AR) is an important indicator of rupture likelihood. The importance of AR is hypothesized to arise from its influence on intra-aneurysmal hemodynamics. It has been conjectured that slower flow in high AR sacs leads to a cascade of biological activities that weaken the aneurysm wall (Ujiie et al.,1999). However, the connection between AR, hemodynamics and wall weakening has never been proven. Animal models of saccular aneurysms provide a venue for evaluating this conjecture. The focus of this work was to evaluate whether a commonly used elastase induced aneurysm model in rabbits is suitable for a study of this kind from a hemodynamic perspective. In particular, to assess whether hemodynamic factors in low and high AR sacs are statistically different. To achieve this objective, saccular aneurysms were created in 51 rabbits and pulsatile computational fluid dynamics (CFD) studies were performed using rabbit specific inflows. Distinct hemodynamics were found in the low AR (AR<1.8, n=25), and high AR (AR>2.2, n=18) models. A single, stable recirculation zone was present in all low AR aneurysms, whereas a second, transient recirculation zone was also found in the superior aspect of the aneurysm dome for all high AR cases. Aneurysms with AR between 1.8 and 2.2 displayed transitional flow patterns. Differences in values and distributions of hemodynamic parameters were found between low and high AR cases including time averaged wall shear stress, oscillatory shear index, relative residence time and non-dimensional inflow rate. This work lays the foundation for future studies of the dependence of growth and remodeling on AR in the rabbit model and provides a motivation for further studies of the coupling between AR and hemodynamics in human aneurysms.

Estimation of aneurysm wall stresses created by treatment with a shape memory polymer foam device

In this study, compliant latex thin-walled aneurysm models are fabricated to investigate the effects of expansion of shape memory polymer foam. A simplified cylindrical model is selected for the in-vitro aneurysm, which is a simplification of a real, saccular aneurysm. The studies are performed by crimping shape memory polymer foams, originally 6 and 8 mm in diameter, and monitoring the resulting deformation when deployed into 4-mm-diameter thin-walled latex tubes. The deformations of the latex tubes are used as inputs to physical, analytical, and computational models to estimate the circumferential stresses. Using the results of the stress analysis in the latex aneurysm model, a computational model of the human aneurysm is developed by changing the geometry and material properties. The model is then used to predict the stresses that would develop in a human aneurysm. The experimental, simulation, and analytical results suggest that shape memory polymer foams have potential of being a safe treatment for intracranial saccular aneurysms. In particular, this work suggests oversized shape memory foams may be used to better fill the entire aneurysm cavity while generating stresses below the aneurysm wall breaking stresses.

The adverse effects of flow-diverter stent-like devices on the flow pattern of saccular intracranial aneurysm models: computational fluid dynamics study

BACKGROUND

Stent deployment across the aneurysmal neck has been established as one of the endovascular methods to treat intracranial aneurysms with or without coils.

OBJECTIVE

The purpose is to study the possible adverse effects of deployment of the new flow-diverter stent-like devices (FD) on the flow characteristics of saccular aneurysm models.

METHODS

Numerical simulations of the blood flow patterns in the artificial models of three aneurysms were studied. One model was designed without an FD stent, the second model with one FD stent, and the third model with two stents. Numerical simulation for incompressible laminar blood flow was conducted in the three artificial cerebral aneurysm models by means of computational fluid dynamics.

RESULTS

There was a noticeable increase in the values of the circumferential pressure distributed on the walls of the aneurysm after stent deployment; this led to an increase the tension of the aneurysm surface and was considered to be an adverse effect. This pressure increase was further aggravated by the deployment of another stent. However, there is a beneficial effect of using FD stents, translating into the reduction of the flow velocity inside the aneurysm and wall shear stress at the inflow zone. This reduction decreases further with the deployment of another stent.

CONCLUSION

Aneurysms become tenser after the deployment of one flow-diverter stent and (more tense still) after after the deployment of another stent. This principle should be kept in mind when choosing which group of aneurysms is the best candidate for such a treatment strategy. This study recommends deploying several FD stents during endovascular procedures until complete arrest of the blood flow occurs during the procedure; otherwise, the aneurysm may become tenser and dangerous if a slow blood flow jet still exists inside it at the end of the procedure.

Endovascular solutions for the management of visceral aneurysms

Visceral artery aneurysms is a rare but important condition associated with significant mortality when rupture occurs. Technological advance has increased the role endovascular therapy plays in their management, particularly in patients whom surgery is considered to pose significant risk. Maintenance of end organ perfusion is vital when selecting the optimal endovascular treatment to exclude the aneurysm. This review will discuss the precautions required in different vascular territory outlining the endovascular treatments available. The evidence supporting the endovascular treatments and associated risks will also be discussed.

Surgical options for the management of visceral artery aneurysms

Visceral artery aneurysm (VAA) is a rare entity but increased use of abdominal imaging has led to an increased prevalence. Rupture is related to a high mortality rate. Open repair, endovascular treatment and laparoscopic techniques have been described as treatment options. In this systematic review we describe the surgical options for treating VAA. A literature search identified articles focussing on the key issues of visceral artery aneurysms and surgical options using the Pubmed and Cochrane databases. Case reports dominate the literature about VAA. Twenty-seven small case series and ten review articles have been published in the last 20 years concerning the surgical options for VAA. The evidence does not exceed level 3. Surgical treatment is dictated by both patient and aneurysm characteristics. Whether VAA should be treated largely depends upon age, gender, presence of hypertension (e.g. in renal aneurysm), aneurysm size and presentation. Aneurysm size and characteristics, anatomical location and presence of collateral circulation dictate the surgical option to be chosen. The mortality and morbidity rates after elective open repair are low. Literature about surgical options for treating VAA remains scarce. Only a few clinical trials have shown the possibilities and results of open surgical repair. In general, there is no consensus on the surgical treatment of VAA and the highest level of evidence is based upon expert opinions.

Endovascular treatment of visceral artery aneurysms with Cardiatis multilayer flow modulator: preliminary results at six-month follow-up

AIM

The aim of this study was to analyze our initial experience with Cardiatis multilayer flow modulator and value its efficacy in the treatment of visceral artery aneurysms (VAA) at one and six months follow up in terms of aneurysms exclusion, patency of collateral vessels (when present) and shrinkage of the lesion.

METHODS

Between June 2009 and June 2010, 19 patients (13 men and 6 women, mean age 60 years, range 19-86) with true visceral aneurysms underwent endovascular procedure with Cardiatis multilayer peripheral flow modulator in 12 clinical centers (10 vascular interventional radiology and 2 vascular surgery). The site of aneurysmal lesions was splenic artery in five cases (26.3%), hepatic artery in five cases (26.3%), celiac trunk in three (15.8%), superior mesenteric artery in two cases (10.5%), renal artery in three (15.8%) and gastroduodenal artery in one case (5.3%). The mean size of all the VAAs was 32.75 mm (±21.6). Early results in term of mortality and complications were evaluated. Follow-up consisted of clinical and CT scan examination at 1 and 6 months with particular attention to sac thrombosis, patency of the stent and collateral vessels (when present) and shrinkage/diameter reduction of the lesion.

RESULTS

Technical success was achieved in all patients. The one perioperative death was due to pulmonary embolism at 24 hours yielding a perioperative mortality rate of 5.3% (1/19 patients). We had not major or access related complications. In two cases we had stent occlusion (one at 48 hours and another at two weeks) leading to a stent patency rate at one month of 87.5% (14/16 patients). At the CT scan performed at one month follow-up we achieved sac thrombosis in 14/16 patients (87.5%) with patency of collateral vessels; the mean size of all the visceral artery aneurysms was 31.68 mm (±21.9). At six-month follow-up we still had complete sac thrombosis in 14/16 patients (87.5%) and patency of stent and collateral vessels in all cases. The mean size of all the lesions at this scheduled control was 27.6 mm (±21.1) with shrinkage of the lesions in 12/16 cases (75%) (shrinkage range 2-15 mm, mean 5 mm ±4.7, P=0.0006, P<0.05).

CONCLUSION

Even if our study has some limitations and longer follow-up is needed, preliminary results showed Cardiatis multilayer flow modulator to be a reliable tool for endovascular aneurysms exclusion of visceral artery aneurysms even in those lesions with collateral vessels arising from the sac or the neck with complete aneurysm thrombosis and shrinkage of the lesion at six-month follow-up. Overcoming limitations of traditional endovascular devices for visceral artery aneurysms exclusion, this new device allows a broaden number of patients, not suitable before for minimally invasive treatment, to undergo exclusion of these lesions with endovascular approach.

Retinal microaneurysm count predicts progression and regression of diabetic retinopathy. Post-hoc results from the DIRECT Programme

OBJECTIVE

To study the association between baseline retinal microaneurysm score and progression and regression of diabetic retinopathy, and response to treatment with candesartan in people with diabetes.

METHODS

This was a multicenter randomized clinical trial. The progression analysis included 893 patients with Type 1 diabetes and 526 patients with Type 2 diabetes with retinal microaneurysms only at baseline. For regression, 438 with Type 1 and 216 with Type 2 diabetes qualified. Microaneurysms were scored from yearly retinal photographs according to the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol. Retinopathy progression and regression was defined as two or more step change on the ETDRS scale from baseline. Patients were normoalbuminuric, and normotensive with Type 1 and Type 2 diabetes or treated hypertensive with Type 2 diabetes. They were randomized to treatment with candesartan 32 mg daily or placebo and followed for 4.6 years.

RESULTS

A higher microaneurysm score at baseline predicted an increased risk of retinopathy progression (HR per microaneurysm score 1.08, P < 0.0001 in Type 1 diabetes; HR 1.07, P = 0.0174 in Type 2 diabetes) and reduced the likelihood of regression (HR 0.79, P < 0.0001 in Type 1 diabetes; HR 0.85, P = 0.0009 in Type 2 diabetes), all adjusted for baseline variables and treatment. Candesartan reduced the risk of microaneurysm score progression.

CONCLUSIONS

Microaneurysm counts are important prognostic indicators for worsening of retinopathy, thus microaneurysms are not benign. Treatment with renin-angiotensin system inhibitors is effective in the early stages and may improve mild diabetic retinopathy. Microaneurysm scores may be useful surrogate endpoints in clinical trials.

Non-dimensional modeling in flow simulation studies of coronary arteries including side-branches: a novel diagnostic tool in coronary artery disease

AIMS

Blood flow, vascular shape and size and local remodeling of the vascular wall are linked through wall shear stress (WSS) signaling. Inter-individual comparison of shape and WSS is hampered by large differences in size of flow and shape. We performed non-dimensional modeling to discriminate different types of coronary artery remodeling based on WSS patterns and vessel morphology.

METHODS AND RESULTS

Blood flow was simulated in three-dimensional reconstructed right coronary artery trees from seven controls, five patients with coronary artery disease (CAD) and five patients with aneurysmatic CAD (AnCAD) classified by expert visual diagnosis. A discriminant model using low WSS area, a remodeling index, and cross-correlation of WSS in main trunks and complete trees (K) as non-dimensional parameters classified CAD and AnCAD correctly and identified three patients with high risk profile and functional disease in controls. The new model was compared with discriminant analysis of identical cases simulated without side-branches. The inclusion of K (information from side-branches) and replacement of the mean diameter by a non-dimensional remodeling index improved the model. We found significant (p<0.005) gender differences in the remodeling index.

CONCLUSION

The combination of non-dimensional modeling and WSS profiling should be further investigated as a novel diagnostic tool in CAD beyond local stenosis.

[Endovascular treatment of a female patient with resistant arterial hypertension secondary to a renal artery aneurysm]

Described herein is a successful therapeutic outcome in a female patient presenting with resistant arterial hypertension secondary to a gigantic intraorganic aneurysm of the right renal artery. Treatment consisted of intravascular prosthetic repair of the parenchymatous portion of the renal artery, eventually making itpossible to entirely bypass the aneurysmatic sac and to restore the lumen of the renal artery, followed by normalization of arterial pressure.

[Long-term patency of a popliteal venous aneurysm treated surgically]

Popliteal venous aneurysms are infrequent but should be screened for with venous ultrasound in patients with acute or chronic venous diseases because of the unpredictable high risk of thromboembolism and potential curability. Therapeutic alternatives are discussed: follow-up, anticoagulation, surgery with different techniques. To illustrate this, we report the case of a 51-year-old woman presenting pulmonary embolism and left popliteal venous aneurysm treated surgically. Anticoagulation was stopped 12 months after surgery and primary patency was maintained 40 months after surgery. In patients with thromboembolism disease, clinicians should search for popliteal venous aneurysms in order to prevent recurrent thrombosis and adapt follow-up and treatment.

Arteria lusoria aneurysm with truncus bicaroticus: surgical resection without restoring blood supply to the right arm

Arteria lusoria, an aberrant or anomalous right subclavian artery, is the most common anomaly of the aortic arch. It may be associated with other congenital anomalies of the heart and great vessels-including, rarely, truncus bicaroticus (a common trunk of both common carotid arteries), and, even more rarely, aneurysmal formation.Herein, we report the case of a 72-year-old man who had both an atherosclerotic aneurysm of an aberrant right subclavian artery and truncus bicaroticus. We resected the aneurysm through a posterolateral thoracotomy and did not restore the distal pulsatile blood supply to the right arm. During long-term clinical follow-up, the patient experienced no arm ischemia or cerebrovascular insufficiency.Aneurysm of arteria lusoria should be suspected in the presence of a right superior mediastinal mass on chest radiographs and should be considered as a cause of new-onset dyspnea, chest pain, or dysphagia. Symptomatic right arteria lusoria aneurysm should be removed promptly after diagnosis. Despite disagreement among investigators regarding the need to restore pulsatile blood flow to the right arm, we recommend reconstructing that flow, when possible.

Origin of axial prestretch and residual stress in arteries

The structural protein elastin endows large arteries with unique biological functionality and mechanical integrity, hence its disorganization, fragmentation, or degradation can have important consequences on the progression and treatment of vascular diseases. There is, therefore, a need in arterial mechanics to move from materially uniform, phenomenological, constitutive relations for the wall to those that account for separate contributions of the primary structural constituents: elastin, fibrillar collagens, smooth muscle, and amorphous matrix. In this paper, we employ a recently proposed constrained mixture model of the arterial wall and show that prestretched elastin contributes significantly to both the retraction of arteries that is observed upon transection and the opening angle that follows the introduction of a radial cut in an unloaded segment. We also show that the transmural distributions of elastin and collagen, compressive stiffness of collagen, and smooth muscle tone play complementary roles. Axial prestresses and residual stresses in arteries contribute to the homeostatic state of stress in vivo as well as adaptations to perturbed loads, disease, or injury. Understanding better the development of and changes in wall stress due to individual extracellular matrix constituents thus promises to provide considerable clinically important insight into arterial health and disease.

Recent advances in the application of computational mechanics to the diagnosis and treatment of cardiovascular disease

During the last 30 years, research into the pathogenesis and progression of cardiovascular disease has had to employ a multidisciplinary approach involving a wide range of subject areas, from molecular and cell biology to computational mechanics and experimental solid and fluid mechanics. In general, research was driven by the need to provide answers to questions of critical importance for disease management. Ongoing improvements in the spatial resolution of medical imaging equipment coupled to an exponential growth in the capacity, flexibility and speed of computational techniques have provided a valuable opportunity for numerical simulations and complex experimental techniques to make a contribution to improving the diagnosis and clinical management of many forms of cardiovascular disease. This paper contains a review of recent progress in the numerical simulation of cardiovascular mechanics, focusing on three particular areas: patient-specific modeling and the optimization of surgery in pediatric cardiology, evaluating the risk of rupture in aortic aneurysms, and noninvasive characterization of intraventricular flow in the management of heart failure.

Popliteal artery aneurysms and popliteal phymas

For the differential diagnosis of popliteal phymas, popliteal artery aneurysms are evaluated. They are frequent among peripheral aneurysms. However, diagnosis is difficult in some patients because clinical symptoms vary. We report 2 patients who consulted our hospital for popliteal phymas. In these patients, surgery was performed via a posterior approach. In 1 patient, reconstruction was conducted using a great saphenous vein graft (SVG). Even when employing the posterior approach, SVG collection and reconstruction are possible without changing the posture for short-distance reconstruction. This procedure may prolong patency in comparison with artificial blood vessels.

[Surgical treatment of symptomatic aneurysm of popliteal artery]

The results of treatment of 17 patients, suffering symptomatic aneurysm of popliteal artery (APA) were analyzed. According to angiographic data, the APA thrombosis was revealed in 6 patients, and according to ultrasonographic Doppler scanning data the APA rupture with hematoma in adjacent tissues was diagnosed in 5 patients. The tactics of treatment was established in accordance with the distal blood flow character: the conservative therapy was conducted in the presence of APA up to 40 mm in diameter in condition of the artery passability preservation and poor distal blood flow--in 6 observation operative treatment was conducted in the presence of satisfactory distal blood flow--in 4, according to urgent indications due to critical ischemia--in 2, and for the aneurysm rupture--in 5. Operative treatment of symptomatic APA showed ineffective in presence of thrombotic complications in 23.1% patients. In conservative and surgical treatment of APA, complicated by an acute thrombosis, the poor results (the lower extremity amputation) were noted in 33.3% patients.

Hyperemic maximal venous outflow unmasks symptomatic lower extremity venous obstruction

Venous obstruction is an underappreciated and often unrecognized component of the pathophysiology of symptomatic chronic venous disease (CVD). Moreover, standard methods used to detect venous obstruction, such as maximal venous outflow, are inadequate as they typically test patients at rest and in the supine position when the pathophysiology of CVD is defined in the upright patient performing exercise. This report describes a patient with incapacitating venous claudication in whom standard noninvasive venous function tests were normal and whose phlebography was interpreted as showing no evidence of venous obstruction. A postocclusive reactive hyperemic technique was used to unmask significant outflow obstruction, leading to operative correction and subsequent symptom resolution.

Effects of cyclosporine, tacrolimus and sirolimus on vascular changes related to immune response

BACKGROUND

Despite the use of newer immunosuppressors such as sirolimus (SRL) and tacrolimus (TRL) in heart transplantation, the rate of humoral rejection has remained unchanged. The aim of this study was to analyze the immunologic and histologic effects of cyclosporine (CsA), SRL, and TRL in a porcine model of arterial transplantation.

METHODS

Each transplant recipient animal (n = 49) received an autograft and an allograft and was then allocated to one of four treatment groups and a 7- or 30-day follow-up period, as follows: a WOT group (without immunosuppressor treatment), 7 days (n = 6) and 30 days (n = 5); a CsA group, 7 days (n = 5) and 30 days (n = 6); an SRL group, 7 days (n = 7) and 30 days (n = 8); and a TRL group, 7 days (n = 6) and 30 days (n = 6). The presence of donor-specific antibodies (DSA) was tested at the end of the follow-up period. Morphometric parameters and inflammatory infiltration were analyzed in the explanted grafts.

RESULTS

At 30-day follow-up, SRL was the only treatment capable of suppressing DSA formation (0 of 7 vs 4 of 5 in the WOT group; p < 0.05). SRL completely prevented aneurismal dilation and reduced the number of macrophages in the allografts. TRL treatment achieved a greater reduction of T lymphocytes. CsA did not prevent the reduction in total vascular area at 7 days that was achieved with the SRL and TRL groups. Animals treated with CsA had the largest number of T lymphocytes and macrophages in both follow-up periods.

CONCLUSIONS

SRL prevented DSA formation and reduced the number of macrophages as compared with TRL and CsA.

Postoperative hepatic artery aneurysms development and remodeling in Ehlers-Danlos syndrome type IV. Case report

Patients affected by Ehlers-Danlos syndrome (EDS) type IV are at risk for aneurysm formation and rupture. This case report shows the extreme vascular fragility of these patients. We studied a 31-year-old man that developed hepatic artery aneurysms 3 weeks after splenectomy. Computed tomography angiography showed the extreme vascular remodeling of the aneurysms. We conclude that remote site complications should be kept in mind by all surgeons in vascular EDS patients even after general surgery operations.

Hypothenar hammer syndrome: gray-scale and color Doppler sonographic appearances

We report a case of hypothenar hammer syndrome following a single severe blunt trauma in a 24-year-old man with a painful pulsatile mass, numbness in the fourth and fifth fingers, and intolerance to cold. The gray-scale and color Doppler sonographic findings are presented with correlation with MRI.

Saccular aneurysms of the extracranial internal carotid artery. Experience and review of the literature

The aim of this study was to describe the surgical technique employed and our results in the treatment of saccular aneurysms of the internal carotid artery at the extracranial level. We describe 3 cases of patients with saccular aneurysms of the extracranial internal carotid who underwent surgery at our unit within the last 3 years. We report on indications for treatment, surgical technique and results in terms of morbidity-mortality and also review the pertinent literature. Surgical treatment was indicated on the grounds of the patients being symptomatic: 2 had a history of cerebral ischemia, and 1 showed local compression symptoms. The surgical approach was presternocleidomastoid cervicotomy extended distally, and in 2 patients was accompanied by nasotracheal intubation to achieve adequate exposure. In 2 cases, we performed an aneurysmectomy with end-to-end anastomosis. In the third patient, the aneurysm neck was ligated from within the sac followed by aneurysmectomy. There was no mortality or neurological morbidity (local or general). The patients remain free from neurological symptoms with a patent carotid axis. Our clinical experience suggests that, despite the anatomically unfavorable location of this type of aneurysm and the greater complexity of the surgical technique, this patient group can be effectively treated. The frequent presence of an elongated carotid axis and an aneurysmal neck means the surgeon can easily restore arterial continuity by direct procedures.

Sonographic diagnosis of inferior mesenteric artery aneurysm and marginal artery of Drummond

We report the case of a patient in whom sonographic examination revealed an aneurysm of the inferior mesenteric artery with severe proximal stenosis and poststenotic dilatation--the enlargement of the proximal portion of the artery of Drummond. This collateral pathway should be kept in mind when studying bowel ischemia, especially when stenosis is present or when there is occlusion of the superior mesenteric artery.

Matrix Metalloproteinase-9 May Play a Role in Recanalization and Recurrence after Therapeutic Embolization of Aneurysms or Arteries

PURPOSE

Matrix metalloproteinase (MMP)-9 plays various roles in vascular healing and angiogenesis. This study was conducted to determine if MMP-9 is involved in healing or recanalization after therapeutic occlusion of arteries or aneurysms.

MATERIALS AND METHODS

Angiographic and pathologic changes were investigated in canine bilateral venous pouch carotid aneurysms embolized with gelatin sponges with or without previous endothelial denudation, a procedure that can prevent recanalization. To assess a potential role of MMP-9, messenger RNA (mRNA) and protein were compared in denuded and nondenuded aneurysms 4, 7, and 14 days after embolization. To assess if MMP-9 is essential to arterial recanalization, transmyocardial angiography and pathologic findings were compared 14 days after carotid occlusion with platinum coils in MMP-9-knockout and wild-type mice.

RESULTS

Denudation of the endothelial lining led to improved angiographic results at 3 weeks (P < .001). Neointimal closure of the aneurysm neck was more complete in denuded versus nondenuded aneurysms. Denudation was followed by a decrease in MMP-9 mRNA (86%, P < .05) and protein (30%, P < .05) 7 days after embolization and a decrease in von Willebrand factor compared with nondenuded aneurysms. MMP-9 immunostaining of axial sections from embolized aneurysms confirmed MMP-9-positive endothelialized clefts, which were absent in denuded aneurysms. Transmyocardial angiography and pathologic examination showed recanalization of one of nine coiled carotid arteries of MMP-9-knockout mice, compared with five of seven controls (P = .035).

CONCLUSIONS

MMP-9 may play a role in recanalization of arteries after coil occlusion and in recurrences after sponge embolization of aneurysms.

Significance of the Early Postoperative Duplex Result in Infrainguinal Vein Bypass Surveillance

BACKGROUND

Duplex surveillance of infrainguinal vein grafts may not be efficient.

METHODS

Consecutive patients who had received infrainguinal vein grafts were enrolled in a duplex surveillance program. A first scan at 6 weeks after surgery categorized grafts into four groups: (a) low risk grafts, (b) mild flow disturbance, (c) intermediate stenosis and (d) critical stenosis. Disease progression was assessed over time.

RESULTS

Of 364 grafts followed-up for a median of 23 months, 236 (65%) had no flow abnormality at 6-weeks, and had a 40-month cumulative patency rate of 82%. The remaining 128 (35%) grafts had a flow disturbance. Of 29 critical stenoses, 15 were repaired, 11 occluded and three did not change. Of 57 intermediate lesions, 32 progressed to critical, nine occluded, two were repaired and 14 did not change or improved. Of 42 mild lesions, 16 progressed to a higher grade, four occluded and 22 did not change or improved. There was no significant difference in graft patency between grafts with repaired stenoses and those without stenoses, but grafts with untreated critical stenoses were associated with lower patency (p<0.001).

CONCLUSIONS

A duplex scan 6 weeks after operation can predict those patients who require continuing duplex surveillance.

Splenic artery aneurysms in pregnancy--a systematic review

Visceral artery aneurysm is an uncommon pathology, with a potential for rupture. Splenic artery aneurysms (SAA) are most commonly (60%) associated with a high mortality rate of 25% in case of aneurysm rupture. This increases disproportionately to 75% among pregnant women with fetal mortality of 95%. Although this is a rare event, because of the associated catastrophic consequences, prompt management of splenic artery aneurysms (SAA) is of prime importance. This systematic review provides up-to-date information about the management of splenic artery aneurysms in pregnancy.

Computer Simulation of Hemodynamic Changes After Right Lobectomy in a Liver with Intrahepatic Portal Vein Aneurysm

BACKGROUND/PURPOSE

Intrahepatic portal vein aneurysm is rare and its natural history is unknown. A 22-year-old healthy man, who wished to donate part of his liver to his diseased father, was incidentally diagnosed to have an intrahepatic portal vein aneurysm. The surgical decision of performing live donor hepatectomy for such a patient is normally difficult. We combined modern imaging reconstruction technologies with scientific computing as a new modality to foresee the risks of surgical complications.

METHODS

Cross-sectional computed tomography images were used to reconstruct the three-dimensional image of portal vein distribution using the 3D-Doctor v3.5 software. The reconstructed images were further employed to generate surface and interior meshes with CFX software. Simulated hemodynamic changes in velocity, pressure, and wall stress were determined for the right lobectomy case pre- and postoperatively.

RESULTS

The simulation results indicated that aneurismal pressure would be elevated significantly to 12.03 mmHg after operation. The left segmental portal venous blood flow would increase from 2.95- to 4.25-fold. The area near the branch point of one left segmental portal vein, which supplies blood to liver segment 4, and the portal vein aneurysm would endure high shear stress gradient. The resulting elevated aneurismal pressure may cause the thin wall to enlarge and rupture, while the high shear stress gradient would lead to vascular endothelial cell injury. Living donor surgery was not recommended hemodynamically based on the simulated results.

CONCLUSION

Scientific computing and modern imaging technologies can be applied together to aid surgeons to make the best decision in difficult clinical situations.

Surgical technique and long-term results after popliteal artery aneurysm repair: Results from 717 legs

BACKGROUND

This study investigated the importance of surgical technique on long-term outcome after treatment of popliteal artery aneurysms (PAAs).

METHODS

Records from 571 patients (717 legs) primarily operated on for PAAs were identified in the Swedish Vascular Registry. Surgical approach, type of graft, and anastomotic and ligation techniques were studied. After mean 7.2 years (range, 2 to 18 years) information on amputation was obtained for all patients, and 190 patients were re-examined with ultrasound imaging.

RESULTS

The approaches used were medial (medial approach group, MAG) in 87%, posterior (PAG) in 8.4%, endovascular in 3.6%, and other in 1.4%. Primary patency at 1 year with venous and prosthetic grafts was 85% vs 81% in the PAG (P = .719) and 90% vs 72% in the MAG (P < .001). Sixty-three legs (8.8%) were amputated <or=1 year, and 80 (11%) had been amputated at re-examination or by the end of follow-up. The median time from operation to amputation of 17 legs amputated after 1 year was 3.1 years (range, 1.1 to 9.8 years). The frequency of late amputation was 3.7% (2/54) in the PAG and 2.6% (15/571) in the MAG. In a Cox regression model, age (odds ratio [OR] 1.06/year, P < .001), emergency procedure (OR 2.67, P < .001), and prosthetic graft (OR 2.02, P = .008) were independently associated with long-term amputation rate. The risk of expansion of the excluded PAA at re-examination was 33% in the MAG and 8.3% in the PAG (P = .014). It was not affected by the ligation technique used.

CONCLUSIONS

The risk of late amputation was higher with prosthetic grafts. Operation with a posterior approach decreased the risk of expansion.

The medial versus the posterior approach in the repair of popliteal artery aneurysms: A multicenter case-matched study

OBJECTIVES

This study was conducted to compare the early and mid-term results of the medial and posterior approaches in the surgical treatment of popliteal artery aneurysms (PAAs).

METHODS

From 1992 to 2006 in three hospitals, 110 popliteal aneurysms needed surgical repair by a posterior or a medial approach. Of 36 aneurysms repaired by the posterior approach, 33 could be case-matched to a medially excluded PAA according to the criteria of (1) patient age, (2) cardiovascular comorbidity, (3) indication for PAA repair, (4) diameter of PAA at time of surgical repair, (5) number of distal outflow vessels at time of surgical repair, and (6) type of bypass or interposition graft (venous or polytetrafluoroethylene).

RESULTS

During the 30-day postoperative period, seven complications (21%) occurred in each group, no patients died, and no amputations were necessary. Two patients in the posterior group vs none in the medial group (P < .05) needed thrombectomy because of occlusion of the reconstruction. The mean follow-up was 47 months (range, 2 to 176). In this period, 13 deaths occurred, but none were related to the previous interventions. The primary patency rates at 6 months and at 1, 3, and 4 years were 84%, 79%, 66%, and 66% in the posterior group and 96% (P < .05), 93% (P < .05), 76% (P = NS), and 69 % (P = NS) for the medial group, respectively. The secondary patency rates at 6 months, and at 1, 3, and 4 years were 100%, 100%, 100%, and 90% in the posterior group and 96%, 96%, 96%, and 90% in the medial group, respectively (P = NS). Limb salvage rates were 97% for the posterior group and 100% for the medial group (P = NS). No neurologic complications or venous damage was seen in either group. Irrespective of approach, venous reconstructions resulted in significantly higher patency rates compared with prosthetic reconstructions at the 3-year follow-up (84% vs 67%, P < .01). During follow-up, which included duplex scanning, two patients in the medial group needed renewed surgical intervention and posterior exclusion because of persistent flow and growth of the native aneurysm.

CONCLUSION

Early (<1 year) primary patency rates of the medial approach were significantly better than the posterior approach, possibly because of the limited posterior exposure. However, in the absence of a significant difference in long-term primary and secondary patency rates between the posterior and medial approach, and considering the substantial risk of aneurysm growth after medial approach (up to 22%), the posterior approach might be the surgical method of preference for PAA repair in the long run.

Cardiac involvement in systemic inflammatory diseases

Systemic inflammatory diseases represent a large group of rare diseases that may involve all organs and also the heart. The three layers of the heart can be affected and some manifestations such as pericarditis in systemic lupus erythematosus are rather well known, yet others are not known even for cardiologists. Modern sophisticated imaging techniques reveal cardiac abnormalities in most of these diseases and the reported frequency of cardiac involvement ranges widely depending upon the applied diagnostic methods and selection of patients. The clinical significance of these findings is not always established. However, better knowledge and awareness of cardiac involvement is necessary because it conveys a major risk for mortality in several of these rare diseases.

Surgical and endovascular treatment of atherosclerotic popliteal artery aneurysms

Popliteal artery aneurysms are the most common peripheral aneurysms. Patients with unrecognized aneurysms may present with acute limb ischemia and considerable threat for limb loss due to thromboembolic complications. This article reviews short-term and long-term results of surgical and endovascular treatment for mainly elective repair of popliteal artery aneurysms. A systemic review was conducted of data in the English literature from 1990. The review included 1 prospective randomized trial, 6 prospective studies, and 42 retrospective studies on the management of popliteal artery aneurysms. These studies contained 2 197 patients with 2 882 popliteal artery aneurysms. Short-term results are acceptable, with average 1-year patency rates of 90% for surgical treatment and 75% for endovascular treatment, and respective limb salvages rates of 95% and 100%. Endovascular treatment lacks long-term follow-up, whereas venous surgical repair has an average 5-year patency rate of up to 85% (prosthetic grafts, 40-80%). There is a need for randomized trials comparing long-term results of surgical versus endovascular treatment of popliteal artery aneurysms. So far, long-term results of elective surgical repair for popliteal artery aneurysms are acceptable if venous grafts are used. In any case, acute repair of popliteal artery aneurysms must be avoided.

Endovascular treatment of asymptomatic popliteal aneurysms: 8-year concurrent comparison with open repair

AIM

The aim of this prospective comparative study was to compare the results of 8-years experience of endovascular treatment (ET) of popliteal aneurysms (PAs) using the Hemobahn/Viabahn endograft with those achieved with open repair (OR). Endpoints were primary and secondary patency rate.

METHODS

The study was a prospective randomized clinical trial from January 1999 to December 2003 and a prospective comparative study from January 2004 to December 2006. Patients with an asymptomatic aneurismal lesion in the popliteal artery 2 cm at angio-computed tomography were included in the study. Indication for ET was PA (proximal and distal neck length >1 cm); contraindications were: 1) age <50 years; 2) poor distal run-off; 3) contraindication to antiplatelet, anticoagulant or thrombolytic therapy.

RESULTS

Between January 1999 and December 2006, of a total of 42 patients with 48 PA, 27 were treated with OR (group A) and 21 with ET (group B). The primary patency rate was 100% in group A and 80.9% in group B at 12 months and 71.4% and 88.1%, respectively, at 72 months; the secondary patency rate at 72 months was 88.15% and 85.9% in groups A and B, respectively. No statistical differences were observed at the log-rank test. During the entire study period, 3 (14.3%) patients in group B required conversion to open surgery because of endograft occlusion.

CONCLUSION

Within the power limitations of this study, ET for asymptomatic PA in patients with suitable anatomy can be considered safe, with long-term results comparable with those of OR.

Endovascular treatment of popliteal artery aneurysms: is the technique a valid alternative to open surgery?

AIM

Feasibility of endovascular repair of popliteal artery aneurysms has been established. The results of this technique and the effect of the learning curve on the occurrence of complications were evaluated in a prospective cohort.

METHODS

Between June 1998 and February 2007, 73 popliteal aneurysms were treated by endovascular means. Primary outcome was stent-graft patency. Secondary outcome was a combined end-point of stent-graft related complications, including occlusion, migration, stent-graft fracture, and stenosis. To study the learning curve, the cohort of patients was divided into 2 groups (group A from 1 to 23; group B from 24 to 73). Cut-off point chosen was the introduction of the more aggressive postoperative anticoagulation protocol with clopidogrel.

RESULTS

Eighteen (25%) stent-grafts occluded. This resulted in a reintervention in 11 patients. Migration, fracture, and stenosis were diagnosed in 9, 3 (2 leading to occlusion), and 2 limbs, respectively; these 14 complications accounted for reinterventions in 8 additional patients. In total, 19 of the 73 limbs (26%) required 20 reinterventions. Overall 3-and 5-year patency rates were 77% and 70% for primary patency, and 86% and 76% for secondary patency, respectively. There were more occlusions in group A (8/23, 35%) versus group B (10/50, 20%) (P= 0.22). With regard to the combined endpoint, there were more events in group A (14/23, 61%) than in group B (16/50, 32%) (P= 0.016).

CONCLUSION

Results of endovascular repair of popliteal artery aneurysms are improving and in range with those of open repair.