Roberto Chiesa

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 Youngs 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.

EVIDENCE BASED ASSESSMENT OF LONG-TERM RESULTS OF PLAQUE INCISION AND VEIN GRAFTING FOR PEYRONIE’S DISEASE

PURPOSE We assessed the long-term outcome of plaque incision and vein grafting in select patients with Peyronies disease by extensive preoperative and postoperative subjective and objective analysis. MATERIALS AND METHODS From January 1995 to June 1998, 50 men 28 to 62 years old (mean age 44) underwent surgery. Patients were evaluated preoperatively, 3 months after surgery and at a mean long-term followup of 32 months by sexual history, physical examination, determination of penile length and degree of curvature, dynamic color power Doppler sonography of the penile vessels and nocturnal RigiScan* evaluation for 3 nights. Study inclusion criteria were penile curvature 45 degrees or greater that made vaginal intromission impossible, stable disease for at least 6 months, patient reported normal penile rigidity, normal penile hemodynamics on color power Doppler ultrasound, normal nocturnal penile rigidity with at least 1 erection nightly (including base and tip rigidity greater than 60%, and a duration of 10 minutes) and absent base-tip discrepancies. Plaque was usually approached via a combined subcoronal and midline sagittal scrotal incision. Maximal rigidity was created intraoperatively and 1 to 3 plaque incisions were made. Saphenous vein patches were then grafted at the incision sites. Postoperatively patients were systemically treated with neurotrophic factors and low molecular weight heparin. Local vacuum supported corporeal stretching was done and weekly alprostadil injections were given to optimize corporeal oxygenation. RESULTS At long-term followup complete penile straightening was achieved in 40 cases (80%), minor residual curvature of 30 degrees or less persisted in 7 (14%) and significant disease recurred in 3 (6%). Penile rigidity was equal to that preoperatively in 47 patients (94%), while 3 (6%) reported clinically significant decreased potency. Penile length was equal to that preoperatively in 30 patients (60%), while 20 (40%) noticed slight penile shortening. Postoperatively penile color power Doppler sonography showed vascular impairment in 5 men (10%) and nocturnal RigiScan testing revealed a significant decrease in nightly erections in 5 (10%). Surgical complications included penile hypoesthesia in 1 case (2%), penile hematoma in 2 (4%), wound infection in 1 (2%) and glandular ischemia in 1 (2%). CONCLUSIONS Plaque incision and vein grafting achieved satisfactory clinical results in the majority of patients with severe and stable Peyronies disease, intact penile rigidity preoperatively, normal penile color power Doppler ultrasound and normal nocturnal RigiScan testing.

Three dimensional time-of-flight magnetic resonance angiography in carotid artery surgery: A comparison with digital subtraction angiography

Three dimensional time-of-flight magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (DSA), considered the gold-standard technique, were compared for pre- and postoperative evaluation of the carotid bifurcation. Images of suitable quality of 194 bifurcations were available with both techniques. Percentage stenosis was graded into 5 groups: A = 0-29%, B = 30-59%, C = 60-89%, D = 90-99%, E = 100% (occlusion). Preoperative MRA (126 bifurcations) overgraded the stenosis in 14 cases and undergraded it in 11. The two techniques agreed in 101 cases and the extent of misgrading was never more than one category. Regression analysis showed a good correlation between the two methods. Severe ulceration was better identified by DSA. As far as the surgical indication was concerned, MRA had a sensitivity of 92.6% and a specificity of 98.3%. In 68 operated cases, postoperative MRA and intraoperative completion angiography showed a satisfactory endarterectomy with no residual stenosis in any of the cases. In conclusion, MRA seems an accurate modality for imaging of carotid bifurcations. Significant limitations still exist for an adequate demonstration of intracranial circulation.

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.

Surgical septic complications in diabetic patients

SummaryIn a retrospective study postoperative septic complications were evaluated in 140 insulin-dependent diabetic patients who underwent surgery. The data collected were matched with those of a group of non-diabetic patients, homogeneous for sex, age, and type of surgical procedure. Patients of each group were further divided into 3 subgroups according to the risk of intraoperative contamination (clean-, clean-contaminated, and contaminated procedures). Diabetic patients had a significantly (p<0.01) higher rate of septic complications in clean- and clean-contaminated procedures particularly of wound infections. Our experience suggests that diabetes represents an important risk factor.

Thoraco-abdominal aorta

Thoraco-abdominal aorta , Thoraco-abdominal aorta , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

Liver biopsy and percutaneous cholangiography using a posterior approach: 500 needle biopsies and 121 cholangiographies

A technique of posterior percutaneous liver biopsy and cholangiography was used in 500 liver biopsies and 121 cholangiographic examinations of the biliary tract. It provided a successful liver biopsy in 98.6 percent of cases and was associated with a less than 2 percent complication rate. Successful cholangiography was possible in all patients with dilated ducts and in 87 percent of patients with normal undilated ducts. Percutaneous cholangiography was associated with a 5 percent complication rate. The advantages of this technique are that it can be performed by relatively inexperienced physicians with minimal risk of hemo- or choleperitoneum. It has a low failure rate and can be performed in obese patients or patients with coagulation defects. The route of entry eliminates the risk of injury to the gallbladder or colon. Due to the posterior position, this technique can be used in relatively uncooperative patients.

Thoracic and Abdominal Aorta Percutaneous Treatment

Aortic disease is a potentially serious condition that in many cases can be diagnosed and treated before it becomes dangerous. The most appropriate management is related to the severity, extension, and site of disease and to the specific patient’s clinical characteristics and risk factors.

Hybrid Procedures forThoraco-Abdominal Aortic Aneurysm

Thoraco-abdominal aortic aneurysm (TAAA) hybrid repair consists of rerouting of abdominal aortic visceral branches followed by TAAA endograft exclusion. In this chapter we report our single-center experience of 34 patients (28 males, median age 68.2 years, range 23 to 83 years) who underwent hybrid TAAA repair (13 type I, 4 type II, 7 type III, 3 type IV — Crawford classification — and 7 aneurysms of the visceral aortic patch) between 2001 and 2009. Patients’ data were prospectively collected in a computerized database. All patients were excluded from standard open surgery because of increased surgical risk and/or local technical concerns. Hybrid TAAA repair has been technically feasible in all cases undergoing TAAA exclusion, with a variety of operative strategies and materials. Typical complications of standard open surgery have not been eliminated by hybrid TAAA repair and there are still significant mortality and morbidity, and new threatening mid-term procedure-related complications have been reported. Larger series of hybrid TAAA repair with clear inclusion criteria and long-term follow-up are needed to establish a standardized operative technique and to make any statistically meaningful comparisons with standard open repair. Based on our experience with high-risk patients, hybrid TAAA repair should currently be limited as an alternative to simple observation in patients unfit for standard open repair.

Endovascular Treatment of Aortic Isthmic Rupture

Thoracic endovascular aortic repair (TEVAR) has recently been considered an appealing alternative to open treatment of traumatic aortic ruptures. However, the feasibility of TEVAR is limited by several problems, including the need for prompt availability of computed tomography imaging studies and endovascular materials, aortic arch angulation, small aortic diameters, and small size of access vessels. Among 32 patients admitted to our institution for a blunt traumatic aortic injury (BTAI) between 2003 and 2010, 24 patients (19 males, mean age 39.4 ± 12.5 years) were treated by means of TEVAR. Twelve patients (50%) were hemodynamically unstable at presentation, and 18 patients (75%) presented severe associated injuries. Twenty patients (83%) were treated emergently, whereas four patients (17%) underwent prior clinical stabilization of severe associated injuries. The primary technical success rate was 100%. No patient required conversion to open thoracic surgical repair. No paraplegia or stroke were observed. Procedure-related complications included an external iliac artery lesion during introducer sheath removal. The left subclavian artery was intentionally covered in seven cases (29%), and revascularized in two patients prior to stent-graft deployment. Associated abdominal surgical procedures were necessary in five patients (21%). Two patients died due to multi-organ failure, for a total in-hospital mortality of 8.3%. At a mean follow-up of 21.2 ± 6.7 months, the remaining patients are well with intact device. In our experience, endovascular treatment of acute traumatic thoracic aortic injury using commercially available stent-grafts allowed us to obtain satisfactory short- and medium-term results.