Animal models in the research of abdominal aortic aneurysms development.

Abdominal aortic aneurysm (AAA) is a prevalent and potentially life threatening disease. Many animal models have been developed to simulate the natural history of the disease or test preclinical endovascular devices and surgical procedures. The aim of this review is to describe different methods of AAA induction in animal models and report on the effectiveness of the methods described in inducing an analogue of a human AAA. The PubMed database was searched for publications with titles containing the following terms "animal" or "animal model(s)" and keywords "research", "aneurysm(s)", "aorta", "pancreatic elastase", "Angiotensin", "AngII" "calcium chloride" or "CaCl(2)". Starting date for this search was set to 2004, since previously bibliography was already covered by the review of Daugherty and Cassis (2004). We focused on animal studies that reported a model of aneurysm development and progression. A number of different approaches of AAA induction in animal models has been developed, used and combined since the first report in the 1960's. Although specific methods are successful in AAA induction in animal models, it is necessary that these methods and their respective results are in line with the pathophysiology and the mechanisms involved in human AAA development. A researcher should know the advantages/disadvantages of each animal model and choose the appropriate model.

Evaluation of cerebrovascular reserve capacity in symptomatic and asymptomatic internal carotid stenosis with transcranial Doppler.

Cerebrovascular reserve capacity (CVRC) is a hemodynamic parameter indicating the brain's capacity to overcome ischemia. Transcranial Doppler (TCD) is a useful device to measure CVRC, with high availability and low cost. The aim of the study is to investigate asymptomatic patients with affected CVRC, who could benefit from CEA. One hundred and forty five consecutive patients (60 symptomatic and 65 asymptomatic), with internal carotid artery (ICA) stenosis >70 % and 20 healthy individuals without internal carotid stenosis underwent TCD-inhalation CO(2) tests in order to measure the CVRC in both hemispheres of each patient. CVRC between asymptomatic and symptomatic patients were significantly different in the 95 % confidence interval (CI) as well as the mean CVRC value in contralateral carotid artery. The correlation between CVRC in the carotid artery with stenosis and the existence of symptoms is significant at the 0.01 level. Additionally, symptoms and CVRC of the contralateral carotid artery are also significant at the 0.05 level and CVRC values in asymptomatic patients and the control group at the 0.01 level. None of the covariant factors, except the age, are significantly correlated with CRVC. CVRC could be an early mark-index to evaluate the risk of stroke in this group of patients and to design their therapeutic approach.

Homocysteine as a risk factor of restenosis after carotid endarterectomy.

AIM: Homocysteine (Hcy) has been identified as a potential risk factor for vascular disease. This study investigates the role of serum Hcy as clinical risk factor for restenosis after carotid endarterectomy (CEA). METHODS: In a prospective design, we studied patients who underwent carotid endarterectomy with venous patch closure technique with respect to alterations of Hcy levels pre and postoperatively. The patients studied were subjected to reevaluation for possible restenosis at time-points 3, 6, 9, 12, 18 and 24 months postoperatively. RESULTS: Fifty-three symptomatic and 37 asymptomatic patients with stenosis of internal carotid artery >70% were studied. Restenosis appeared in 7.25% of the patients within 24 months postoperatively. Hcy was the only parameter that correlated significantly with the presence of restenosis (P=0.010) and the presence of type VI (complicated) atheromatous plaque (P=0.005) within 24 months postoperatively. CONCLUSION: Hcy levels were found to be statistically significantly correlated with both the presence of complicated atheromatous plaque and the degree of internal carotid artery restenosis after CEA.

The effect of revascularization procedures on healing of mixed arterial and venous leg ulcers.

AIM: The optimal management of venous leg ulcers in patients with concomitant peripheral artery disease (PAD) remains unclear. The aim of the present study was to evaluate the effectiveness of revascularization procedures in healing of the ulcers of mixed etiology. METHODS: During a 6-year period a total of 20 patients with evidence of chronic venous insufficiency, impaired arterial perfusion (ABI<0.75) and active leg ulcer were treated. Patients with moderate PAD (0.5

Elective bypass surgery for chronic mesenteric ischemic disease: report of 3 cases and review of the literature.

Chronic mesenteric ischemic disease is an unusual cause of chronic abdominal pain. We present our experience from open surgical treatment of patients with this rare disease followed by a short review of the literature. During the period 2006-2008, three patients were referred to our department with clinical and radiological findings of chronic mesenteric ischemic disease. In all patients, at least 2 out of 3 splachnic vessels (celiac artery, superior and inferior mesenteric artery) were occluded, with severe stenosis of the third. Open surgical revasculation was performed in all patients, using autologous or synthetic (Dacron) bypass grafts. Graft patency was examined with triplex ultrasound studies at 3, 6 and 12 months postoperatively and/or follow up CT angiography. All patients had patent grafts during the follow up period and have regained their normal body weight. Immediate and late results, technical details and controversies in open surgical revasculation for chronic mesenteric ischemic disease are reviewed. In conclusion open surgical revasculation for chronic mesenteric ischemic disease is a technically challenging procedure with good results in patients younger than 70 years old , with long occlusions of the splachnic vessels and severe calcification of the vessel wall.

ICU transfer after elective abdominal aortic aneurysm repair can be succesfully reduced with a modified protocol. A fourteen year experience from a University Hospital.

AIM: To compare different selective criteria for Internal Care Unit (ICU) admission in two different timeframes, after abdominal aortic aneurysm (AAA) repair. A retrospective audit of acquired data was performed. METHODS: During a period of fourteen years (1994-2008), 1152 patients underwent an elective open operation for infrarenal abdominal aortic aneurysm, in our department. Six hundred and two patients (Group A) were treated in the period January 1994-January 2003, and 550 patients (Group B) between January 2003 and August 2008. Postoperatively, all patients were transferred to postanesthesia unit (PAU). After a 2 hours period of close observation, they were transferred either to the ICU or to the surgical ward, according to certain selective criteria (SC). In group A we used SC-A, for admission to an ICU, and in group B we used new, stricter, criteria (SC-B). Thirty-day mortality and morbidity, elective admissions to ICU, rate of subsequent ICU admission, from ward to ICU, and the mean hospital and ICU length of stay, were compared between the two groups. RESULTS: The use of SC-B resulted in a significant reduction of elective admissions to ICU (3.1% vs 8.5%, P<0.001). Nevertheless, the portion of patients, which were transferred with a severe postoperative complication from the ward to ICU, remained similar between the two groups (1.1% vs 0,9%, in group A and B, respectively). All other endpoints were similar in both groups. CONCLUSION: Modifying the protocol of ICU transfer, after elective abdominal aortic aneurysm repair, we can reduce the number of patients requiring ICU, without compromising patients' safety.

Carotid endarterectomy versus carotid angioplasty with or without stenting for treatment of carotid artery stenosis: an updated meta-analysis of randomized controlled trials.

Carotid angioplasty with or without stent placement (CAS) has been proposed as an alternative to carotid endarterectomy (CEA) for the treatment of carotid artery stenosis. We performed a systematic review and meta-analysis of randomized controlled trials to compare the safety and efficacy of endovascular techniques with surgery for carotid stenosis. We searched MEDLINE, PubMed and Cochrane databases to identify randomized controlled trials comparing CAS with CEA. Both random and fixed effects models were used to calculate the pooled odds ratios (OR) and their confidence intervals, with values lower than one indicating a benefit from the endovascular approach. Continuity correction was used for studies with zero events in one arm. We identified 11 trials randomizing a total of 3 258 patients; 1 623 to CEA and 1 635 to CAS. By random effects model, there was no significant difference between the treatments for any stroke (OR, 1.28; 95% CI, 0.82-2.02), or death or any stroke at 30-day (OR, 1.30; 95% CI, 0.92-1.84) and death or any stroke at 6 months (OR, 1.34; 95% CI, 0.86-2.09) or 1 year (OR, 1.41; 95% CI, 0.24-8.27). However there was a significantly higher risk of 30-day death or any stroke (OR, 1.33; 95% CI, 1.01-1.75) after CAS by fixed effects model. Endovascular treatment significantly reduced the risk of 30-day cranial nerve injury (OR, 0.13; 95% CI, 0.04-0.44). In conclusion treating carotid artery stenosis with CAS offers lower rates of cranial nerve injury compared with CEA. CAS could not be proved to be as safe as CEA in treating carotid artery stenosis. The results of ongoing randomized trials comparing CAS with CEA are easily awaited because they may provide sufficient evidence for a change in clinical practice.

Transradial access for carotid artery stenting: a single-center experience.

AIM: The aim of this study was to report our initial experience using the radial artery as access for carotid artery stenting (CAS) and review the existing literature. METHODS: From January to June 2008, nine high-risk consecutive patients were treated with carotid stents by using the radial artery as an access point. Major complications (perioperative myocardial infarction, stroke, transient ischemic attack [TIAs] and death) and minor complications (radial artery occlusion or hematomas) were evaluated during this procedure. RESULTS: Seven of these patients had a right (77.8%) and two had a left (22.2%) sided carotid artery stenosis. Patients were symptomatic (TIAs or strokes or both) and had a >60% stenosis of the internal carotid artery. The technical success rate was 100% and all patients mobilized two hours after the procedure and were discharged home on the first postoperative day. No major or minor complications were reported. CONCLUSION: Patients with vessel pathology or unfavorable anatomy in the iliofemoral arteries or/and the aorta, can be candidates for CAS through the radial artery. Refinement of the technique and improvement in endovascular devices may lead to the replacement of the conventional femoral access by the transradial route in the near future.

Guided remote endarterectomy for superficial femoral artery occlusions: a technical note.

The aim of this paper was to describe a new modification of the remote endarterectomy for the treatment of long superficial femoral artery (SFA) occlusions and to present our preliminary results. Through a subinguinal incision and arteriotomy over the SFA origin, a hydrophilic guidewire was introduced into the subintimal plane of the SFA and advanced distally until reentry into the distal patent popliteal artery. The hydrophilic guidewire is exchanged for an Ablatz wire to provide support for the advancement of the single endarterectomy ring. The MollRing Cutter was introduced in the SFA after the removal of the single endarterectomy ring and it was advanced until the re-entry point. The atherosclerotic core was removed and a nitinol self-expanding stent was placed at the peripheral end of the endarterectomy. Arteriotomy was closed with a patch. Guided subintimally-assisted remote endarterectomy seems to be a successful and safe modification of the traditional technique in the treatment of SFA occlusion, in patients with critical limb ischemia.

Cellular proliferation in complicated versus uncomplicated atherosclerotic lesions: total cell population, foam cells and newly formed microvessels.

Although cellular proliferation is a key component in the progression of atherosclerosis, research so far has been focused primarily on VSMCs. In this study we attempted to evaluate overall proliferation rates in general, as well as foam cells and the endothelial cells lining newly formed plaque microvessels in particular. For this purpose, cellular proliferation was assessed through immunohistochemical staining for PCNA in 10 fresh human carotid artery samples received from patients undergoing carotid endarterectomy. Overall proliferative activity was found significantly higher (P

Vein patch angioplasty with non-penetrating titanium clips. Comparison to standard suture technique.

Our purpose was to compare the Vascular Closure Staples (VCS) clips to a standard suture technique for vein patch angioplasty in a porcine model. Six female pigs underwent vein patch angioplasty of the common iliac arteries with either VCS clips or continuous suturing. The reconstructed vessels were evaluated macroscopically, angiographically and histologically after two months by re-operation. There was a non significant trend towards shorter reconstruction (6.5 +/- 1.8 min. for clips vs. 8.5 +/- 1.7 min. for sutures, p = 0.15) and clamp times when clips were used (8.4 +/- 1.5 min. vs. 10.1 +/- 1.3 min., p = 0.15). At re-operation all vessels were found patent without significant histological differences regarding the intimal reaction. VCS clips are a reliable alternative to sutures for vein patch angioplasty.

Can the diameter of endoluminal shunt influence the risk of hyperperfusion syndrome after carotid endarterectomy?

AIM: The aim of this study was to evaluate if there is a possible relation between the size of endoluminal shunt, in carotid endarterectomy (CEA), and the risk of postoperative hyperperfusion syndrome. METHODS: We retrospectively studied prospectively collected data from 156 patients, who were subjected to CEA using shunting and vein patch angioplasty. One hundred and thirty-eight of the patients had bilateral, high grade (> or = 90%) internal carotid lesions and the remaining 18 had a high-grade stenosis (> or = 90%) and a contralateral internal carotid artery (ICA) occlusion. In 81 patients varying diameters of shunts were used (8-14 Fr) according to the diameter of ICA (group A) and in the other 75 patients (group B) only the smallest shunt was used (8 Fr). Development of hyperperfusion syndrome was evaluated both clinically and radiologically with magnetic resonance imaging. RESULTS: Fifteen patients developed hyperperfusion syndrome (9.6%), between 0 to 6 days postoperatively. Thirteen belonged to group A (86.6%), and 2 (13.3%) belonged to group B (P<0.05). One had an intracerebral hemorrhage (0.6% of the study group) the 3rd postsurgical day. CONCLUSIONS: During CEA in patients with high-grade bilateral lesions, we recommend the use of a shunt with small diameter: this aims at reducing the risk of hyperperfusion syndrome.

Laparoscopic hybrid techniques for ectopic or accessory renal arteries debranching in complex endovascular aneurysm repair.

The aim of this study was to report an assisted or totally laparoscopic approach for renal revascularization in patients with congenital renal vascular anomalies during endovascular abdominal aneurysm repair (EVAR). In three patients with an ectopic main or a large accessory renal artery (>3mm) arising from the aneurysm, laparoscopic exposure of the target renal artery and the ipsilateral iliac bifurcation was performed. In two patients a small incision was made over the area between the iliac bifurcation and the renal target vessel in order to facilitate the anastomotic procedure. In the third patient a totally laparoscopic bypass between a big left inferior renal polar artery and the left common femoral artery was carried out. In all patients the aneurysm was successfully excluded using an endovascular graft. Technical success was achieved in all three patients. The mean total operative time was 126 min (range 110-152 min). The mean hospital length of stay (HLS) was 3.5 days. Renal function of the patients remained unchanged. All bypasses were found to be patent and endoleaks was not observed at 6-month follow-up. Laparoscopic assisted or totally laparoscopic renal revascularization may increase the applicability of EVAR in complex abdominal aortic aneurysms.

Totally laparoscopic aortohepatic bypass for aortic debranching during endovascular thoracoabdominal aneurysm repair.

INTRODUCTION: Endovascular grafting of the aorta is gaining widespread acceptance for treating aortic aneurysms. Para-renal aneurysms or thoraco-abdominal aneurysms may be a relative contra-indication for endovascular aneurysm repair (EVAR) unless visceral vessels can be debranched. REPORT: We describe a case of thoraco-abdominal aneurysm extending from the descending thoracic aorta to the level of coeliac artery. A totally laparoscopic retrograde aorto-hepatic bypass was performed in conjunction with endograft exclusion of the aneurysm and coverage of the coeliac artery ostium. DISCUSSION: Laparoscopic debranching of visceral vessels extends the indications of EVAR.

A short incision for carotid endarterectomy results in decreased morbidity.

OBJECTIVES: To investigate the effect of a short incision (<5 cm) on the complication rate of the carotid endarterectomy (CEA). DESIGN: A retrospective cohort study. PATIENTS AND METHODS: From January 1994 to December 2005, 874 patients underwent 1048 primary carotid endarterectomy (CEA) procedures. Seven hundred and sixty nine operations were performed through a long neck incision (group A), while 279 were performed through a smaller incision (<5 cm) according to a standard protocol (group B). Preoperative and postoperative cranial nerve assessment was completed on all patients. The main outcome measures were stroke, death, cranial and cervical nerve injuries rates. RESULTS: The 30-day mortality rate was 0.26% in group A and 0.35% in group B (p=.792). The stroke rate was 0.13% and 0% in group A and B respectively (p=.839). The mean length of stay was 2.59 days in group A and 1.67 days in group B (p<.0001). In group A the overall incidence of motor and sensory nerve deficits was 13.5% (104 CEA, 92 patients) but in group B 2.9% (8 CEA, 7 patients, p<.0001, odds ratio [OR] 0.189, 95% confidence interval [CI] 0.091-0.393). CONCLUSIONS: Carotid endarterectomy through a small incision is a feasible and safe approach that provides cosmetic results and fewer nerve complications without compromising the safety of the procedure.

Changing patterns in the etiology of acute lower limb ischemia.

AIM: The aim of this study was to examine the causes of acute lower limb ischemia (ALLI) in a major referral center in Greece. METHODS: Hospital records of patients that were admitted with ALLI between January 1, 2000 and December 31, 2004, were retrospectively reviewed for this purpose. A total of 440 cases of ALLI in 351 patients were identified. RESULTS: In 174 (39.54%) cases, the ischemia was attributed to embolism; in 221 (50.23%) to thrombosis and in the remaining 45 (10.23%) to less common causes of ALLI (trauma [iatrogenic and non], vasculitis, dissection). Of 174 cases of embolism, 136 (78.16%) were of cardiac origin, 22 (12.64%) were due to non-cardiac emboli, while in the remaining 16 cases (9.2%) no specific origin of embolism was found. Of 221 cases of thrombosis 66 (29.86%) concerned native arterial thrombosis, while 155 (70.14%) concerned postinterventional thrombosis, including 144 (65.16%) cases of bypass graft thrombosis and 11 (4.98%) cases of iliac or femoral stent thrombosis. Sixty patients were admitted more than once with ALLI, most commonly due to repeated bypass graft thrombosis (85%). The latter was diagnosed in 32.73% of all ALLI cases and presented more often than native arterial thrombosis by a ratio of approximately 2.2:1. CONCLUSION: This study indicates that currently the leading cause for hospital admissions in patients with ALLI is thrombosis which most commonly occurs in bypass grafts rather than in native arteries.

Abdominal aortic aneurysm repair in patients with end stage renal disease.

OBJECTIVE: Abdominal aortic aneurysm (AAA) in patients with end stage renal disease (ESRD) represents a challenging therapeutic problem. This study was undertaken to analyze the surgical outcome of AAA repair in patients with ESRD and discuss the optimal peri-operative management of problems that resulted. METHODS: Between January 1995 and January 2005, 11 patients with ESRD underwent abdominal aortic aneurysm repair. All patients were under chronic haemodialysis. Risk factors related to surgical morbidity were evaluated. RESULTS: The average age was 68 years (57-84 years). Nine patients were men: 8 were hypertensive, 6 had diabetes, 4 had coronary artery disease, 3 had suffered a previous stroke, 3 had prior myocardial infarct and 8 were smokers. The duration of haemodialysis was 19 months (range 2 to 46 months). Five of the 11 patients had bilateral common iliac aneurysms in addition to the abdominal aortic aneurysm. The average diameter of infrarenal AAA was 6 cm (4.8-7.5). The mean duration of operation was 191 min. All patients underwent haemodialysis on the day before operation with an average period of 8.5 hours (6-12) and 2 to 20 hours postoperatively. The mean follow-up was 11.5 months (range 1 to 93 months). None of the patients died during the 30-day postoperative period. Two patients died from heart failure 3 and 7 months later. CONCLUSION: Abdominal aortic aneurysm can be repaired in patients with end stage renal disease with good results, despite the increased morbidity and mortality of this population.

Simultaneous venous gangrene in both lower and upper limbs. A case report.

Cancer-related venous gangrene is an extremely rare paraneoplastic syndrome. Here, we present the case of a woman, who suffered from cervical cancer of the uterus and was admitted to our Clinic with venous gangrene in both the right lower and upper limbs. Neither the anticoagulant therapy, nor thrombolysis, succeeded in improving her clinical condition. Cancer is one of the most important causes of venous thromboembolism. Venous gangrene is rarely seen in these patients. Despite adequate therapy, venous gangrene in some very rare occasions may progress to affect further limbs. Mortality in these patients remains very high.

Outcome of infrainguinal revascularization for critical limb ischemia in diabetics with end stage renal disease.

BACKGROUND: End stage renal disease [ESRD] and diabetes have a negative effect on outcome of arterial reconstructions, because they are associated with a vulnerability to infection, an infrageniculate arterial occlusive disease and an increased perioperative risk. The combination of both in critically ischemic patients is traditionally considered a great threat to their limb or life. The risk/benefit ratio of revascularization in this clinical setting is marginal and therefore the decision making is controversial. This study was undertaken to determine the results of arterial reconstruction in patients with end-stage renal disease and diabetes mellitus. PATIENTS AND METHODS: The outcome of 97 patients undergoing 121 arterial reconstructions due to lower limb threatening ischemia were reviewed. Primary and secondary patency rates as well as survival and limb salvage were estimated. RESULTS: Thirty-day operative mortality rate was 10.3%. At one month, one year and 2 year follow-up, the survival rate was 89.7%, 77.6% and 44.2% respectively. Limb salvage at 6 months was 85.6%, at 12 months 75.3% and at 2 years 56.3%. The primary and secondary patency was 92.4% and 93.2% at 6 months and 71.7% and 72.7% at 12 months, respectively. CONCLUSIONS: Diabeticpatients with ESRD attained an acceptable graft patency and limb salvage but they sustained higher perioperative mortality and morbidity and reduced survival.