Carotid Endarterectomy: experience in 8743 cases

INTRODUCTION

Recently published case series of patients undergoing carotid endarterectomy suggested a reduction in the rate of perioperative neurologic events when compared to those reported in the large randomized trials performed in the 1990s, without great differences between high and low risk patients.

METHODS

As a major center of Vascular Surgery we prospectively collected data on 8743 carotid endarterectomy procedures (eversion technique 75%, patch closure 17.5%) performed in the period 1992-2009.

RESULTS

Perioperative mortality was 0.32% (27/8743) with myocardial infarction being the most frequent cause (9 patients). Perioperative neurological morbidity was 1.04% (91/8743) with 51 major and 40 minor strokes. In 201 cases (2.3%) a cervical hematoma (suture-line bleeding in 41 cases and or diffuse oozing in 160 cases) in the early postoperative period necessitated urgent wound revision. In 262 (3.0%) cases we observed permanent or transient lesions of cranial nerves in the postoperative period. There was no significant difference in the combined ipsilateral stroke and perioperative death rate in octogenarian patients (2.1% in octogenarians and 1.2% in younger patients, p>0.05), even though an increasing trend was evident.

CONCLUSIONS

Carotid endarterectomy has a reduced rate of perioperative complications when compared to those previously reported in literature. The low complication rate is related to improved preoperative patients evaluation, surgeons' increasing experience and to surgical and anesthesiological techniques. Carotid angioplasty and stenting should have their results compared to these real world results of carotid endarterectomy in order to asses their reliability when treating extracranial cerebrovascular disease.

Visceral Artery Aneurysms

Visceral artery aneurysms (VAA) frequently present as life-threatening emergencies. The purpose of this study was to review our experience with VAA treatment. Between 1988 and April 2002, 31 VAA were treated in 28 patients (14 males, 14 females) with average age of 55 +/- 15 years. The most common locations were the splenic artery (16) and the hepatic artery (7). Three patients underwent emergency surgery, 22 patients had elective open surgery, and 7 patients underwent endovascular treatment. In the surgical group the perioperative mortality rate was 3.6%. The perioperative morbidity rate was 7.1% (one case of respiratory distress manifested in the immediate postoperative period and one urgent case of bilious fistula). In the endovascular group none of the patients died; the perioperative morbidity rate was of 14.3% (one case of hepatic artery thrombosis after failure of gastroduodenal artery aneurysm embolization). Failure of the procedure was 42.9% (3 cases of aneurysm recanalization). In conclusion, we believe that an aggressive surgical approach is justified, even in the case of asymptomatic VAA, because of the low morbidity and mortality rates. Endovascular treatment should be reserved for selected cases.

Carotid endarterectomy in the octogenarian: outcomes of 345 procedures performed from 1995-2000

The purpose of this study is to evaluate the efficacy and the safety of carotid endarterectomy (CEA) in the octogenarian patient. From January 1995 to December 2000, we have performed 3430 CEAs in 2743 patients: 345 CEAs in 269 octogenarian patients (Group 1) and 3085 CEAs in 2474 younger patients (Group 2). Age was the only selection criteria for including patients in Group 1. Octogenarians' perioperative mortality (1.4%) was greater than that in Group 2 (0.3%) (p<0.05). No differences can be found between the groups' perioperative ipsilateral stroke rates (1.7% in Group 1 vs 1.2% in Group 2) and combined ipsilateral stroke and death rates (2.3% in Group 1 vs 1.3% in Group 2) (p>0.05). The octogenarians' Kaplan-Meier 6-year overall and free-stroke survival rates were 86 and 76% respectively. CEA can be performed in selected octogenarian patients with low early and late mortality and neurologic morbidity rates.

Vascular prosthetic graft infection: epidemiology, bacteriology, pathogenesis and treatment

Vascular prosthetic graft infection remains a major surgical challenge. Prevention of risk factors and antibiotic therapy can reduced but not eradicate it. Management of infected vascular grafts depends on several factors, including the location of the infected prosthesis, the extent of infection, and the underlying micro-organism. Classic treatment consists of extra-anatomic bypass grafting. The disappointing results due to the high mortality and amputation rate have kindled interest in alternative approaches, such as in situ reconstruction with antibiotic-bonded prostheses, autogenous veins or arterial allografts.

PURPOSE

We focused on the treatment of aortic graft infection by means of both fresh and cryopreserved arterial allograft. Here, the experience of the Italian Collaborative Vascular Homograft Group is reported.

METHODS

Between March 1994 and December 2000 seventy-nine patients with aortic graft infection were treated. The results of 68 patients are analysed. Eleven patients were treated with fresh, and 57 with cryopreserved homograft. Emergency surgical procedures were performed in 12 patients (17%). Aortoenteric fistula was diagnosed in 22 patients. The mean interval between the first procedure and the insertion of a homograft for patients with infected aortic graft was 3 years (range 1-15). The mean duration of follow-up was 30 months (range 1-68). Clinical and duplex scanning evaluation were routinely performed. Computer tomography (CT), magnetic resonance (MR), or arteriography were performed on the basis of duplex scanning results.

RESULTS

The analysis was performed on 68 cases for which there were sufficient reliable data. Eleven deaths occurred during the early postoperative period (30 days), a mortality rate of 16%. There were also seventeen late deaths, a mortality rate of 25%. Eleven patients had graft occlusion; six cases were successfully treated with thrombectomy. In three cases leg amputation was necessary. The results of fresh and cryopreserved homografts were compared. No significant differences of early postoperative mortality, late mortality, homograft-related mortality, graft failure were observed. The presence of aortoenteric fistula is a negative predicting factor of perioperative early mortality, which causes a rapid decline in the survival curve. Thirty-six months after the surgery the actuarial survival of the patients was 57% and the actuarial patency of the allograft was 41%.

CONCLUSION

No significant difference in terms of clinical outcome was observed when using fresh, rather than cryopreserved homografts. The only factor that significantly influenced the survival rate appeared to be the aorto-enteric fistula.

Hyperammonemia and chronic hepatic encephalopathy: an in vivo PMRS study of the rat brain

The brain energy metabolism of rats affected by chronic hepatic encephalopathy due to portacaval shunting was monitored by in vivo 31P-nuclear magnetic resonance spectroscopy before and after ammonium acetate administration. With respect to healthy unoperated and to sham operated controls, portacaval shunting decreased the levels of the nuclear magnetic resonance (NMR) visible brain phosphocreatine and nucleoside phosphates, and the intracellular [free Mg(2+)]. Ammonium acetate induced a further decrease of the levels of the NMR detectable phosphocreatine and nucleoside triphosphates and of the [free Mg(2+)], while the PMR spectra of the brain of non-shunted rats did not show any significant change even after treatment with ammonium acetate.

Intraoperative stenting of the internal carotid artery after unsuccessful eversion endarterectomy

Stenting of the internal carotid artery (ICA) has been shown to be feasible in atherosclerotic lesions, in restenosis after carotid endarterectomy, and in spontaneous carotid dissections. To correct an intimal flap that detached distal occlusion of the ICA after eversion carotid endarterectomy, as shown with intraoperative completion angiography, we successfully used stenting of the ica with a self-expandable stainless steel stent placed during surgery through the common carotid artery.

Fresh and cryopreserved arterial homografts in the treatment of prosthetic graft infections: experience of the Italian Collaborative Vascular Homograft Group

Following the experience of cardiac surgeons with homografts in the treatment of infective aortic valve endocarditis, cardiovascular surgeons have investigated in situ revascularization by means of homografts in the management of vascular prosthetic graft infections. Preliminary results are encouraging, but their late fate in long-term follow-up and the influence of preservation techniques are still under investigation. This article reports the experience of the Italian Collaborative Vascular Homograft Group, with the use of fresh and cryopreserved arterial homografts for the treatment of prosthetic graft infections. Between March 1994 and December 1996, 44 patients with prosthetic graft infection were treated with homografts (13 preserved at 4 degrees C, 31 cryopreserved). The mean age of the patients was 65 years. Emergency surgical procedures were performed in eight patients (18%). Sepsis was diagnosed in 11 patients, aortoenteric fistula in 13, and false aneurysms in 10. Staphylococcus was the main cause of infection. The types of vascular reconstruction with homograft were: 32 aortobifemoral, 3 aortoaortic, 2 iliofemoral, 4 peripheral, and 3 axillobifemoral. Human lymphocyte antigen (HLA) and antibody (ABO) blood group system compatibility between donors and recipients was not respected. The mean duration of follow-up was 15 months (range 1-33). Clinical and duplex scanning evaluations were routinely performed. Computed tomography (CT) or magnetic resonance (MR) scanning or arteriography were performed on the basis of duplex scanning results. There were six deaths during the early postoperative period (30 days) with a mortality rate of 13.6%. During the follow-up there were five late deaths with a mortality rate of 11.4%. Eight patients had graft occlusion. Three cases were successfully treated with thrombectomy. Two cases were successfully treated with femoropopliteal bypass with autologous vein. In three cases leg amputation was necessary. The results of fresh and cryopreserved homograft were compared. No significative differences of early postoperative mortality, late mortality, homograft related mortality, and graft occlusion were observed. We have evaluated the actuarial survival of the patients and the actuarial patency of the homografts on the aortoiliac reconstructions. Twelve months after the surgery the actuarial survival of the patients was 73% and the actuarial patency of the homografts was 56%. In our preliminary experience, we have not observed any significant difference in terms of clinical outcome by using fresh rather than cryopreserved homografts. In the near future it will be our policy to employ only cryopreserved homografts. Moreover, we will extend vessel harvesting to nonheart-beating donors, thus maximizing retrieval. The aforementioned solutions will supply the best graft availability to obtain dimensional and ABO compatibility between donors and recipients.

Biomechanics of abdominal aortic aneurysm in the presence of endoluminal thrombus: experimental characterisation and structural static computational analysis

OBJECTIVES

To evaluate the role played by biomechanical and geometrical parameters of endoluminal thrombus and of aortic wall on abdominal aortic aneurysm (AAA) behaviour.

MATERIALS AND METHODS

Tensile tests on 21 AAA thrombus specimens from six patients undergoing AAA repair and numerical evaluation of aneurysmal aortic wall stress and strain distribution. Parameters of the analysis were lumen eccentricity, thrombus Young's Modulus and the aortic wall constitutive equation.

RESULTS

There was a linear stress/strain for all the thrombus specimens. The numerical analyses show the mechanical behaviour of AAA as a function of lumen eccentricity and biomechanical parameters.

CONCLUSIONS

Well organised thrombus reduces the effect of the pressure load on the aneurysmal aortic wall.

In search of biological markers of high-risk carotid artery atherosclerotic plaque: enhanced LDL oxidation

The oxidation of low density lipoprotein (LDL) is a key event in the development and progression of atherosclerosis because it generates molecular epitopes that are more atherogenic than parent LDL. We found previously that patients with carotid atherosclerosis have a significantly higher titer of autoantibodies against oxidatively modified LDL than normal subjects. The aim of this study is to correlate biological markers of in vivo LDL oxidation with the degree of carotid stenosis and of plaque ulceration (PU) in a series of patients undergoing carotid endoarteriectomy (CEA). Ninety-four consecutive patients (68M and 26F, aged 67.3 +/- 8.2 years) who underwent CEA at our institution between June 1993 and January 1994 were included in the study. The degree of carotid stenosis and the presence and extent of PU were correlated with the level of autoantibodies (IgG) against oxidatively modified LDL (Cu++-oxidized [oxLDL] or malondialdehyde derivatized LDL [MDA-LDL]), that consistently mirrors the occurrence of oxidative modifications in vivo. A statistically significant correlation (r = 0.23, p = 0.039) was found between the degree of carotid stenosis and antiMDA-LDL specific ratio (a parameter that describes the specificity of LDL towards other proteins as target for oxidative modification). A statistically significant correlation was also found between the PU score and antioxLDL IgG (r = 0.32, p = 0.011), antiMDA-LDL IgG (r = 0.25, p = 0.045) and antiMDA-LDL IgG specific ratio (r = 0.38, p = 0.002). None of the classical biochemical parameters (total, LDL and HDL cholesterol and triglycerides) correlated with the above-mentioned plaque characteristics. The results shown, support the use of biological markers of in vivo LDL oxidation (antioxidatively modified LDL autoantibody titers) to evaluate the clinical setting of high-risk carotid atherosclerosis both in screening and in follow-up studies.

Avidin and 111In-labelled biotin scan: a new radioisotopic method for localising vascular graft infection

OBJECTIVES

To evaluate a new imaging technique, for diagnosis of prosthetic vascular graft infection. Avidin is a protein which accumulates nonspecifically at sites of inflammation or infection. Due to its extremely low dissociation constant with biotin sites of infection can be imaged, using avidin as a pre-target, followed by injection of 111In-labelled biotin. This technique is much simpler than the common scintigraphic methods which employ labelling of blood components and its target-to-background ratio is greater than the methods employing radiolabelled proteins.

DESIGN

Prospective clinical study.

SETTING

A single department of vascular surgery and one of nuclear medicine of a Northern Italian hospital.

MATERIALS

Between May 1993 and May 1994, 31 grafts in 26 patients were studied; the series included 23 men and three women with a mean age of 65.5 years (range 54-76 years). The prosthetic graft (Dacron -16, ePTFE -15) were: aortoaortic 5, aortobifemoral 15, aortoiliac 1, and femoropopliteal 10. Sixteen patients were suspected of having a vascular graft infection (Group A), the other 10 patients served as controls (Group B). 20 mg of Avidin were injected iv, followed 24 h later by i.v. injection of 500 micrograms of Biotin labelled with 74 MBq of 111In.

CHIEF OUTCOME MEASURES

Whole-body imaging was performed at 10 min and 2 h post-injection, along with SPECT imaging when indicated. Scan results were correlated with the traditional imaging modalities and the clinical outcome of the patients.

MAIN RESULTS

In Group A: two patients (three grafts) were excluded from the study, there were six true-positives, one false-positive and 11 true-negatives. Results in Group B: 10 true-negatives. The overall sensitivity was 100%, the specificity 95%, the accuracy 96%, the positive predictive value 86% and the negative predictive value 100%.

CONCLUSIONS

These data suggest that Avidin/111In-labelled Biotin scintigraphy is a useful non invasive diagnostic method for early diagnosis of suspected prosthetic vascular graft infection.

Mural thrombi in abdominal aortic aneurysms: MR imaging characterization--useful before endovascular treatment?

PURPOSE

To evaluate magnetic resonance (MR) imaging accuracy in the characterization of mural thrombi in abdominal aortic aneurysms (AAAs).

MATERIALS AND METHODS

Forty-five patients (37 men, eight women; mean age, 68 years) with an AAA with mural thrombus thicker than 1 cm at sonography underwent T1- and T2-weighted spin-echo MR imaging. The thrombi were prospectively classified as one of three signal intensity (SI) categories: category 1 corresponds to low SI on both T1- and T2-weighted images; category 2, high SI on T1-and T2-weighted images; and category 3, inhomogeneous SI with hyperintense areas on both T1- and T2-weighted images. During surgery, thrombi were classified as organized, unorganized, and partially organized. MR imaging and surgical findings were compared.

RESULTS

SI category 1 corresponded to organized thrombi in 24 of 24 patients. Category 2 corresponded to unorganized thrombi in 11 of 11 patients. In category 3, focal hyperintense areas corresponded (both for presence and location) to unorganized portions of partially organized thrombi in 10 of 10 patients.

CONCLUSION

MR imaging is accurate in AAA thrombus characterization.

A new ePTFE stretch graft for aorto-iliac reconstructions. Surgical evaluation and one year follow-up with magnetic resonance imaging

Since its introduction at the beginning of the 60s Dacron has proved to be a reliable and durable substitute for aortic reconstructions. It is however susceptible to late thrombosis, infection and aneurysmal dilatation in a significant number of cases. ePTFE vascular prosthesis, introduced in 1972, have proved to perform well for peripheral reconstructions and was used in aortoiliac position since 1980. In 1991 a new type of ePTFE rendered longitudinally extensible (Gore-Tex Stretch) was introduced into clinical practice. The aim of this study is to evaluate surgical performance, short term patency and interaction with periprosthetic tissues of Gore-Tex Stretch straight and bifurcated prosthesis. Between October 1991 and December 1993, 59 patients underwent aortic reconstruction at our Institution either for infrarenal aortic aneurysm (19 patients, 16 males, 3 females, mean age 68.8 +/- 8.5 years) or for aortoiliac occlusive disease (40 patients, 36 males, 4 females, mean age 60.5 +/- 7.2 years). Forty-eight bifurcated and eleven straight grafts were implanted using Gore-Tex sutures. Preoperative workup included Ultrasonography, Magnetic Resonance Imaging (MRI) in patients with aneurysms and Intra Arterial Digital Subtraction Arteriography (DSA) in patients with occlusive disease. Intraoperative parameters were recorded. Postoperative follow-up included ultrasonographic evaluation at 1st and 7th day, 15th postoperative week and at 3 monthly intervals; Intra Venous DSA before dismission and MRI at the 1st and 15th postoperative week. Intraoperatively the grafts proved to be soft and flexible with good handling and suturing characteristics. Perioperative bleeding was 480 +/- 299 ml for occlusive disease cases and 633 +/- 314 for aneurysm cases. No operative mortality was recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

LDL oxidation in patients with severe carotid atherosclerosis. A study of in vitro and in vivo oxidation markers

Among the various risk factors involved in the development and progression of carotid atherosclerosis, the oxidation of LDL has been proposed to play a relevant role. LDL oxidation has been investigated in 94 patients with severe carotid atherosclerosis undergoing elective carotid artery endarterectomy and in 42 matched control subjects. LDL oxidation was evaluated in all patients as (1) the susceptibility to in vitro oxidation, (2) vitamin E concentration and its efficiency in LDL, and (3) the presence of autoantibodies against oxidatively modified lipoprotein to monitor the occurrence of the oxidative processes taking place in vivo. No difference was detected between control subjects and patients concerning vitamin E concentration and the kinetics of conjugated diene formation in isolated LDL exposed to CuSO4. However, vitamin E efficiency was lower (9.6 +/- 4.2 versus 30.2 +/- 7.6 min/nmol vitamin E) and the duration of the vitamin E-independent lag phase was longer (105.5 +/- 16.5 versus 58 +/- 11.8 minutes) in the patient group. Autoantibodies against oxidatively modified lipoproteins were measured with an ELISA method using native LDL, Cu(2+)-oxidized LDL (oxLDL), or malondialdehyde-derivatized LDL (MDA-LDL) as antigens. To monitor cross-reactivity of the antibodies detected with other oxidatively modified proteins, human serum albumin (HSA) and MDA-derivatized HSA (MDA-HSA) were also employed. The antibody titer was calculated as the ratio of antibodies against modified versus native proteins.(ABSTRACT TRUNCATED AT 250 WORDS)