[The role of vascular endothelial growth factor (VEGF)]

The authors present the role of VEGF in microaneurysm formation, blood-retinal barrier breakdown, development of capillary nonperfusion and retinal neovascularization in pathogenesis of diabetic retinopathy. Inhibitors of VEGF in treatment of diabetic retinopathy are presented.

Extensive dynamics in location, shape, and size of aneurysms in a patient with idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome. Idiopathic retinal vasculitis, aneurysms, and neuroretinitis

PURPOSE

To describe an unusual case of idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome with rapid dynamics in the number and appearance of the aneurysms.

DESIGN

Observational case report.

METHODS

Clinical and angiographic data of the patient were reviewed.

RESULTS

In the course of only 6 months, preexisting retinal aneurysms resolved while new ones appeared. Changes were observed in the shape and size of preexisting lesions. The resolution of lesions in eyes previously untreated by laser is reported for the first time.

CONCLUSIONS

Vascular lesions in IRVAN syndrome may show an unusually rapid turnover. The resolution of aneurysms is a part of the natural course of the disease and may occur without previous retinal laser photocoagulation.

Brain tissue oxygenation monitoring supplementary to somatosensory evoked potential monitoring for aneurysm surgery. Initial clinical experience

The object of the study was to evaluate brain tissue oxygenation (p(ti)O2) for intra-operative monitoring of critical ischemic events during early cerebral aneurysm surgery of the anterior circulation supplementary to somatosensory evoked potentials (SEPs). P(ti)O2 was continuously evaluated during surgery for an intracranial aneurysm in 28 patients. Standard cortical SEP monitoring was simultaneously performed. The two monitoring methods were compared by evaluating their respective responses to intra-operative events (particularly temporary vessel occlusion), clinical and neuroradiological outcome. P(ti)O2 and SEPs were reliably used for monitoring in 16 patients. Seven patients were excluded due to too high or too low p(ti)O2 readings or initial absence of SEPs (six patients). Of 64 intra-operative events 19 events (eight patients) were associated with a significant decrease in p(ti)O2 (below 10 mmHg), 22 events (13 patients) were associated with a significant change in SEP amplitude (< 50% decrease related to baseline). Temporary vessel occlusion (six SEP andp(ti)O2 changes each in eightpatients) and surgical dissection were most likely to be followed by significant changes in a monitoring method. Intra-operative p(ti)O2 was found to be a safe, rapid method for documenting ischemic events. P(ti)O2 was found to supplement SEP monitoring. The use of p(ti)O2 measurement as a routine monitoring method in aneurysm surgery is limited by its focal spatial resolution. Nevertheless, it might be helpful as an adjunct in situations when SEPs are absent at baseline, in aneurysms when parent vessel anatomy is complex or if temporary vessel occlusion is planned.

Extracranial head and neck circulation aneurysms in a case of polyarteritis nodosa

Polyarteritis nodosa (PAN) is a rare systemic necrotising medium vessel vasculitis. The hallmark of this condition is aneurysms which are seen in visceral arteries. Aneurysms of extracranial neck and head vessels are rare. We describe a case of PAN who had such aneurysms together with characteristic aneurysms in the mesenteric circulation.

Reversal of pulmonary hypertension after ligation of a brachiocephalic arteriovenous fistula

The arteriovenous (AV) fistula is the access method of choice for long-term hemodialysis according to DOQI guidelines. Among the recognized complications of upper extremity AV fistulae fashioned for hemodialysis are infection, aneurysm formation, and high-output left ventricular failure. We describe a novel cardiopulmonary complication--secondary pulmonary hypertension resulting from an aneurysmal brachiocephalic AV fistula. The clinical presentation, investigation, management, and pathophysiology of this complication are discussed.

Changes of flow characteristics by stenting in aneurysm models: influence of aneurysm geometry and stent porosity

An endovascular technique using a stent has been developed and successfully applied in the treatment of wide neck aneurysms. A stent can facilitate thrombosis in the aneurysm pouch while maintaining biocompatible passage of the parent artery. Insertion of the stent changes the flow characteristics inside the aneurysm pouch, which can affect the intra-aneurysmal embolization process. The purpose of this study is to clarify the velocity and wall shear stress changes that are caused by stenting in fusiform and lateral aneurysm models. We used a flow visualization technique that incorporated a photochromic dye in order to observe the flow fields and measure the wall shear rates. The intra-aneurysmal flow motion was significantly reduced in the stented aneurysm models. Coherent inflow along the distal wall of the aneurysm was diminished and inflow was distributed along the pores of the stent wall in the stented models. Also, sluggish intra-aneurysmal vortex motion was well maintained in the stented aneurysm models during the deceleration phase. A less porous stent generally reduced the intraneurysmal fluid motion further, but the porosity effect was not significant. The magnitude and pulsatility of the wall shear rate were reduced by stenting, and the reductions were more significant in the lateral aneurysm models compared to the fusiform aneurysm models. The hemodynamic changes that were observed in our study can help explain the efficacy of in vivo thrombus formation caused by stenting.

True giant common hepatic artery aneurysm associated with obstructive jaundice: a case report

The appropriate treatment for extrahepatic hepatic artery aneurysms remains controversial, with arguments for and against embolization. We describe a case of a giant true aneurysm of the common hepatic artery associated with obstructive jaundice of nonhemobilia origin. The patient, a 49-year-old previously healthy man, presented with upper midepigastric pain, jaundice, and low-grade fever. The diagnosis of the aneurysm was mainly based on computed tomography scan findings. The aneurysm was successfully embolized using wire coils, and the patient was operated on for acute abdomen. Necrotizing acalculus cholecystitis was found, and cholecystectomy followed by aneurysmectomy without hepatic artery reconstruction was performed. The jaundice subsided spontaneously, and the patient was discharged in good condition. Giant common hepatic artery aneurysms can be managed by either surgery or embolization. In the absence of liver ischemia there is no need for common hepatic artery reconstruction unless a bilioenteric bypass has to be performed to resolve the issue of jaundice. If the latter is required, reconstruction of the hepatic artery might be justifiable to maximize the blood supply to the bile duct.

Intra-aneurysmal pressure after incomplete endovascular exclusion

PURPOSE

An endoleak results from the incomplete endovascular exclusion of an aneurysm. We developed an experimental model to analyze hemodynamic changes within the aneurysm sac in the presence of an endoleak, with and without a simulated open collateral branch.

METHODS

With a latex aneurysm model connected to a pulsatile pump, pressures were measured simultaneously within the system (systemic pressure) and the aneurysm sac (intrasac pressure). The experiments were performed without endoleak (control group) and after creating a 3.5-mm (group 1), 4.5-mm (group 2), and 6-mm (group 3) diameter orifice in the endograft, simulating an endoleak. Pressures were also registered with and without a patent aneurysm side branch.

RESULTS

In each endoleak group, the intrasac diastolic pressure (DP) and mean pressure (MP) were significantly higher than the systemic DP and MP (P =.01, P =.006, and P =.001, respectively), although the pressure curve was damped. The presence of an open side branch significantly reduced the intrasac DP and MP.

CONCLUSION

In this model, intrasac pressures were significantly higher than systemic pressures in the presence of all endoleaks, even the smallest ones. Intrasac pressures higher than systemic pressure may pose a high risk for aneurysm rupture. Although patent side branches significantly reduce these pressures, the aggressive management of an endoleak should be pursued.

Multi-detector row CT angiography of lower extremity arterial inflow and runoff: initial experience

PURPOSE

To assess the patterns of lower extremity arterial inflow and runoff opacification with four-channel multi-detector row computed tomographic (CT) angiography in a cohort of patients with disease warranting imaging of the lower extremity arterial system.

MATERIALS AND METHODS

Twenty-four patients with symptomatic lower extremity arterial occlusive or aneurysmal disease underwent imaging with four-channel multi-detector row CT from the supraceliac abdominal aorta through the feet. Transverse sections were acquired with a 2.5-mm nominal detector width and pitch of 6.0 (3.2-mm effective section thickness) following intravenous injection of 174-185 mL of iodinated contrast medium (300 mg iodine per milliliter). In each patient, attenuation measurements were recorded in 16 arterial and 16 venous locations. In 18 patients, two radiologists assessed the detectability and stenosis degree of 21 arterial segments per patient relative to these features at conventional angiography.

RESULTS

A mean scanning time of 66 seconds was required to cover a mean of 1,233 mm, resulting in a mean of 908 transverse reconstructions. All 504 arterial segments were depicted and analyzable. Mean arterial attenuation ranged from 253 HU in the midabdominal aorta to 357 HU in the popliteal artery and 253 HU in the dorsalis pedis or posterior tibial artery measured inferior to the tibiotalar joint. Maximum mean venous enhancement (99 HU) was observed in the saphenous vein at the ankle, with all other venous stations measuring less than 74 HU.

CONCLUSION

The arteries of lower extremity inflow and runoff can be reliably depicted with minimal venous enhancement by using multi-detector row CT.

Effect of Guglielmi detachable coil placement on intraaneurysmal pressure: experimental study in canines

BACKGROUND AND PURPOSE

Treatment of ruptured aneurysms with Guglielmi detachable coils (GDCs) has been shown to prevent repeat bleeding. To assess whether GDC coiling alters aneurysmal pressure, we measured intraaneurysmal pressure in two canine types of carotid artery aneurysms before and after GDC placement.

METHODS

A 0.014-inch guidewire with a pressure transducer was inserted into parent arteries and domes of surgically created aneurysms. Intravascular static pressures were recorded before and during saline power injections (10, 20, and 30 mL over 1 and 2 s), before and after GDC placement. Common femoral arterial pressure was monitored.

RESULTS

Saline power injections reproducibly and abruptly increased pressure in parent arteries and aneurysms. Mean intraaneurysmal pressure varied (18 +/- 4 [10 mL] to 75 +/- 15 mm Hg [30 mL]), independent of injection duration. Intraaneurysmal baseline pressures were higher after GDC placement (111 +/- 10 versus 93 +/- 15 mm Hg; P =.05). Aneurysmal pressure increases with saline injections were slightly higher after GDC placement, which dampened intraaneurysmal pressure amplitude at baseline (26.5 +/- 5.6 versus 19.6 +/- 7.4 mm Hg; P =.003) and during hypertension (25.3 +/- 5.4 versus 19.8 +/- 7.5 mm Hg, P =.002). The pressure increase slope with saline injection was delayed with GDC placement (0.24 +/- 0.1 versus 0.38 +/- 0.19 s; P <.001).

CONCLUSION

Graded saline power injections into parent arteries can rapidly increase intraaneurysmal pressure. GDC treatment did not attenuate mean intraaneurysmal pressures, but both dampened the pressure amplitude and delayed pressure increases during locally induced hypertension.

Venous aneurysms of the wrist

We describe 2 cases of primary atraumatic venous aneurysm affecting the wrist. Both aneurysms were in branches of the cephalic vein in close proximity to the radial artery. The definitive treatment for these venous aneurysms was surgical excision. There was no recurrence after 9 years in case 1 and after 11 years in case 2. Modern diagnostic modalities were used, including physical examination, Doppler ultrasonography, aspiration, magnetic resonance imaging, and venography. The pathologic analysis was consistent with those venous aneurysms reported in other parts of the body. The hand surgeon should be aware of this rare condition when formulating a differential diagnosis for soft tissue masses of the wrist.

Examination of the apoptotic pathway and proteolysis in the pathogenesis of popliteal artery aneurysms

OBJECTIVES

to investigate the role of apoptosis, expression of death-promoting molecules and mediators of apoptosis in the development of popliteal artery aneurysms.

METHODS

ten popliteal artery aneurysm (PAA) specimens were obtained from patients undergoing elective surgical repair. Normal controls were popliteal arteries obtained from patients without PAA undergoing infrainguinal bypass surgery (n=8). Standard histochemistry techniques were used to assess elastic lamellae fragmentation and inflammatory infiltrate in PAA. Vascular smooth muscle cells (VSMC), macrophages, T lymphocytes, death-promoting molecules, CPP-32, Fas, p53, perforin, apoptosis-mediating Bcl-2 family proteins and apoptotic death substrate, poly(ADP-ribose) polymerase (PARP) were detected immunohistochemically. Detection of apoptosis was by TUNEL assay. Proteolytic activity was determined by 10% gelatin gel zymography.

RESULTS

there is a conspicuous disruption and fragmentation of elastic lamellae in PAA as compared to normal arteries. Increased gelatinolytic activity was observed at 92, 84, 72 and 67 kDa in PAA tissues. There is a significant decrease of VSMCs in the PAA walls (p=0.02). The control arteries had fewer CD68+ macrophages and CD3+ T cells in their media (p<0.01). There was a significant increase in the number of cells undergoing apoptosis in aneurysmal tissue than in the normal vessels, (p<0.02) as well as an increased expression of Bax, CPP-32, Fas, p53 and perforin.

CONCLUSIONS

the data confirm the architectural disruption of the PAA wall and illustrate an apparent biological response involving inflammatory infiltrate, apoptosis and signalling molecules capable of initiating cell death. In addition to compromising the mechanical integrity of the vessel wall, VSMC loss may contribute to imbalance in the protein profile, accelerating extracellular matrix degradation that could favour PAA development.

The fate of small aneurysms of the internal iliac artery following proximal ligation in abdominal aortic aneurysm repair

To assess the natural history of small internal iliac artery aneurysms (IIAA) measuring 2.0-3.0 cm in diameter, proximally ligated in association with abdominal aortic aneurysm (AAA) repair, we examined 9 of 12 patients who underwent this type of surgery. Postoperative computed tomography scanning demonstrated that three IIAAs were still patent and the other six were thrombosed. An increase in the maximum diameter from that at the time of surgery was seen in four IIAAs. One patient suffered serious complications in that a dilated IIAA caused right ureteral obstruction and subsequent hydronephrosis accompanied by unilateral renal dysfunction. This was successfully treated by resection of the IIAA. The findings of this analysis led us to conclude that small IIAAs associated with AAA repair should be treated by either endoaneurysmorrhaphy or resection of the aneurysm after both proximal and distal ligation.

Real-time observation of hemodynamic changes in glomerular aneurysms induced by anti-Thy-1 antibody

BACKGROUND

Blood flow in the microvasculature plays a pivotal role in determining the outcome of injury and repair in inflamed tissue. Real-time observation of the kidney microvasculature, including the glomerular capillary tufts, is extremely difficult because of the methodological limitations of currently available microscope optics. In the present study, we attempted to analyze hemodynamic events that occurred in vivo during microvascular regeneration following destruction of the glomerular capillary tuft, functionally and quantitatively by the use of a real-time confocal laser-scanning microscope (CLSM) system.

METHODS

A polyethylene catheter was inserted into the carotid artery to allow blood pressure measurement. Mesangiolytic lesions producing microaneurysms were induced by the injection of anti-Thy-1.1 antibody. On days 3 and 7 after antibody injection, we examined hemodynamic changes under an intravital microscope equipped with real-time CLSM in combination with a high-speed CCD video camera. To measure vessel diameter and erythrocyte velocity, rats were injected with fluorescein isothiocyanate (FITC)-labeled dextran and FITC-labeled red blood cells (RBCs).

RESULTS

On day 3 of the disease, mean arterial blood pressure was 112 +/- 5 mm Hg, which was significantly higher than that of normal rat or of rats on day 7 (93 +/- 1 and 101 +/- 9 mm Hg, respectively). Within mircroaneurysms on day 3, RBC velocity was greatly suppressed. By day 7, RBC velocity, in glomeruli with normal appearances, recovered to about half of the level seen in normal controls (430.6 +/- 284.7 microm/sec), while in narrowed glomerular tufts, it was still only 104.6 +/- 35.1 microm/sec.

CONCLUSIONS

The noninvasive procedure, using CLSM in combination with a high-speed video camera, allowed us to examine hemodynamic events quantitatively and to analyze microvascular architecture three dimensionally in the kidney. It is useful for estimating hemodynamic response and vascular regeneration in vivo and may be promising for clinical application.

Aneurysmal dilatation of the paraumbilical vein in an infant

The paraumbilical veins are one of the most common collateral pathways developing in portal hypertension. Aneurysmal dilatation of a patent paraumbilical vein is a very unusual finding. We report the first infant case of a paraumbilical vein aneurysm and its Doppler ultrasound findings.

Vascular pathology in the throwing athlete

Vascular pathology in the upper extremity of a throwing athlete comprises a spectrum of serious disorders apt to threaten the patient's career and the viability of the involved parts. Such pathology includes digital vessel thrombosis, proximal thrombosis with distal embolization, vessel aneurysm, and vessel compression, such as in thoracic outlet syndrome and quadrilateral space syndrome. This article provides a description of vascular disorders prone to result from sports activities and a review of published data relevant to throwing athletes. Recognition of vascular compromise as a cause for dead arm syndrome or painful digital dysfunction among athletes is essential to prevent the grave consequences of progressive ischemia.

Asymptomatic aneurysm of the proximal right subclavian artery: a rare ultrasound diagnosis

True aneurysms of otherwise normal subclavian arteries are uncommon peripheral vascular anomalies. Most patients with subclavian artery aneurysms are symptomatic by presenting neurologic signs. We report a young woman who had an asymptomatic true aneurysm of the right subclavian artery assumed to be of congenital origin. This case is unique in that the aneurysm was in the extremely rare anatomic location of the right supraclavicular fossa between the origins of the right subclavian artery and the vertebral artery. Aneurysms of the right subclavian artery may represent a potential pitfall in conventional gray-scale ultrasound of the neck particularly the supraclavicular fossa. Differential diagnosis includes cervical cyst, pharyngo-esophageal diverticulum, vascular anomalies, struma, enlarged lymph node, as well benign or malignant neoplasms. Color duplex ultrasound should be performed as the method of choice for further analysis of suspected aneurysms. In this report the role of B-mode ultrasound and color duplex ultrasound is discussed in relation to digital subtraction- and MR angiography in confirmation of the diagnosis.

Mechanotransduction and arterial smooth muscle cells: new insight into hypertension and atherosclerosis

Vascular cells depend on multiple stimuli to maintain a biomechanically and biologically stable environment. Mechanical stresses contribute significantly to multiple cellular processes that regulate vascular structure and function. For example, fluid shear stresses control endothelial cell molecular responses. Less attention has focused on responses of the smooth muscle cell, the 'other' major vascular cell, to mechanical stimuli, in part because of the experimental difficulties in applying precisely controlled deformation. With the advent of new bioengineered devices, combined with modern technologies for studying molecular expression, we are beginning to understand how the smooth muscle cell responds to and controls the biomechanical environment. These studies will help us to understand vascular diseases where vascular mechanics plays a prominent role, such as hypertension, aneurysm formation and atherosclerotic plaque rupture.

Surgical treatment of extracranial internal carotid artery aneurysms

PURPOSE

Extracranial internal carotid artery aneurysms (EICAs) can be treated by carotid ligation or surgical reconstruction. In the consideration of the risk of stroke after internal carotid artery (ICA) occlusion, the aim of this study was to report the results of reconstructive surgery for these aneurysms, including lesions located at the base of the skull.

METHODS

From 1980 to 1997, 25 ICA reconstructions were performed for EICA: 22 male patients and 3 female patients (mean age, 54.4 years). The cause was atherosclerosis (n = nine patients), dysplasia (n = 12 patients), trauma (n = three patients), and undetermined (n = one patient). The symptoms were focal in 15 cases (12 hemispheric, three ocular), nonfocal in three cases (trouble with balance and visual blurring), and glossopharyngeal nerve compression in one case. Six cases were asymptomatic, including three cases that were diagnosed during surveillance after ICA dissection. In nine cases, the upper limit of the EICA reached the base of the skull. A combined approach with an ear, nose, and throat surgeon allowed exposure and control of the ICA.

RESULTS

After operation, there were no deaths, one temporary stroke, two transient ischemic attacks, and 11 cranial nerve palsies (one with sequelae). The ICA was patent on the postoperative angiogram in all but one case. During follow-up (mean, 66 months), there were two deaths (myocardial infarction), one occurrence of focal epileptic seizure at 2 months, and one transient ischemic attack at 2 years. In December 1998, duplex scanning showed patency of the reconstructed ICA in all but one surviving patient.

CONCLUSION

Surgical reconstruction is a satisfactory therapeutic choice for EICA, even when located at the base of the skull.

Paraclinoid aneurysms of the internal carotid artery: hydraulic simulation study on their locations and shape of the carotid siphon

Hemodynamics of paraclinoid aneurysms were investigated focusing on the effects of their locations and shape of the carotid siphon. A transparent silicon model of the carotid siphon was constructed and a model aneurysm was attached to the outside of the curvature at three different sites. Glycerol solution was perfused into the model, and the half-life of the dye injected into the aneurysm was calculated as an index of the stagnant flow. Values of half-life changed significantly depending on the aneurysmal location and the siphon angle. When the siphon angle was 0 degree where C2 and C4 segments were parallel to each other, the half-life value was the lowest in the C2-C3 junction aneurysm, highest in the C3 segment aneurysm and intermediate in the C2 segment aneurysm. While the C2-C3 junction aneurysm maintained low values regardless of the angle, the C3 segment aneurysm values decreased and C2 segment aneurysm values increased with increases in the angle. These changes of half-life occur because the point at which the faster moving fluid component strikes the curved wall changes according to the siphon angle. These results are considered useful to determine the surgical indications, treatment modalities and post-surgical management of the aneurysms.

Microaneurysms in the development of diabetic retinopathy (UKPDS 42). UK Prospective Diabetes Study Group

AIMS/HYPOTHESIS

To determine whether microaneurysms, in the absence of other lesions, have a predictive role in the progression of diabetic retinopathy in Type II (non-insulin-dependent) diabetes mellitus.

METHODS

Retinal photographs taken at diagnosis in patients participating in the United Kingdom Prospective Diabetes Study, and thereafter at 3 yearly intervals, were assessed using a modified Early Treatment of Diabetic Retinopathy grading system for lesions of diabetic retinopathy and end points of vitreous haemorrhage and photocoagulation. The number of microaneurysms in each eye was recorded.

RESULTS

The changes between diagnosis and later photographs were analysed in 2424 patients at 6 years, 1236 at 9 years and 414 at 12 years. Of the 2424 patients studied in the 6 year cohort 1809 had either no retinopathy or microaneurysms only at entry. In these patients the presence of microaneurysms alone and also the number of microaneurysms had a high predictive value for worsening retinopathy at 3, 6, 9, and 12 years after entry into the study (e. g. at 6 years chi(2) for trend = 75 on 1 df, p < 0.001). The predictive value of the presence or absence of microaneurysms and their number at 3 years from diagnosis and subsequent worsening retinopathy was similar to that at entry.

CONCLUSION/INTERPRETATION

Microaneurysms are important lesions of diabetic retinopathy and even one or two microaneurysms in an eye should not be regarded as unimportant.

Isolated iliac artery aneurysms in patients with or without previous abdominal aortic aneurysm repair

BACKGROUND

Isolated iliac artery aneurysms (IAA) in patients with or without previous abdominal aortic aneurysm (AAA) repair are rare. We wanted to compare the presentation, distribution, treatment, outcome and patterns of subsequent aneurysm formation in these patients.

METHODS

We retrospectively reviewed patients with isolated IAA over a 10-year period. Patients with primary isolated IAA (group 1) were compared with patients who presented with IAA after previous AAA repair (group 2).

RESULTS

There were 23 patients in each group. Demographics and comorbidities were similar. No aneurysms were detected outside of the iliac system in group 1; 22% of patients in group 2 had other aneurysms. The mean time after AAA repair to IAA diagnosis was 8.8 +/- 3.2 years for operated on patients. The in-hospital mortality was 0% for elective cases and 50% for emergency cases for both groups. Three patients in group 2 (13%) developed new aneurysms during follow-up, whereas the only new aneurysm in group 1 was a contralateral IAA.

CONCLUSIONS

Patients with new IAA after AAA repair have a greater tendency to develop further aneurysms in other sites, synchronously or metachronously. The time to detection of new IAA after AAA repair is at least 5 years in most cases. In both groups, a quarter to a third of patients present with rupture, with a resultant mortality of 30% to 50%, whereas those operated on electively have minimal morbidity and almost no mortality.

Long-term follow-up of endoluminal grafting for aneurysmal and occlusive disease in the superficial femoral artery

PURPOSE

To examine the long-term outcome of patients treated with endoluminal grafts (ELGs) for aneurysmal and occlusive disease in the femoropopliteal (FP) segment.

METHODS

ELGs of radially expandable polytetrafluoroethylene with terminal Palmaz stents were used to form intimal conduits to revascularize lengthy occlusive disease and exclude aneurysms in the FP segment. Patient records were reviewed retrospectively for outcome.

RESULTS

Fifty-five (98%) of 56 ELGs were placed successfully in 51 patients treated from August 1993 to February 1996. Over a mean 36-month follow-up, 28 (50%) ELGs occluded. Half of these failures reflected early technical difficulties. There were 11 (20%) stent stenoses, 6 in the proximal stent and 5 in the distal device. The majority of the graft failures were treated with endovascular techniques; however, FP bypass was required in 7 (25%) patients, while 2 (7%) were not treated. Life-table analysis demonstrated 46% primary and 68% secondary patency rates at 24 months. Among demographic and procedural variables, only previous dilation or stent procedures in the target artery was associated with failure (p < 0.0001).

CONCLUSIONS

The prototype ELG used in this series demonstrated durability similar to conventional surgical therapy utilizing synthetic material. Endoluminal grafting of FP lesions may be a more durable alternative to classical bypass once devices and techniques are refined.

[White-noise field campimetry in HIV+ patients]

PURPOSE

The first morphological changes in eyes with HIV infection are microvascular disease of the retina with cotton-wool spots and microaneurysms. The study was performed to find out if evidence of disturbances of ocular microcirculation can be established by non-invasive methods.

PATIENTS AND METHODS

Twenty-seven patients with HIV infection and without opportunistic infections underwent thorough ophthalmologic examination with threshold-oriented, suprathreshold perimetry (TAP 2000 ct, Oculus) and white-noise field campimetry (TEC, Oculus).

RESULTS

Visual field examination was normal in 23 out of 27 patients (85%), whereas 4 patients showed relative field defects in at least one eye. In white-noise field campimetry 13 out of 23 perimetrically unaffected patients (56%) perceived scotomas in one or both eyes. These scotomas were not stable. Three of 4 patients with relative scotomas in the visual field had cotton-wool spots in the retina and showed a stable scotoma in campimetry. Visual acuity, IOP, and cup/disc ratio were within normal ranges.

CONCLUSION

White-noise field campimetry complements the standard examination of patients with HIV and might be capable of indicating disturbances of ocular microcirculation by a non-invasive method before morphological changes in the retina can be seen.

Improved graft patency and altered remodeling in infrainguinal vein graft reconstruction for aneurysmal versus occlusive disease

PURPOSE

This study attempted to determine whether autogenous vein used for infrainguinal reconstruction in patients with aneurysmal disease might demonstrate an altered adaptive response compared with those patients who underwent reconstructive surgery for occlusive disease, potentially altering graft patency.

METHODS

From 1974 to 1997, 43 patients underwent vein grafting for 60 popliteal artery aneurysms (PAA).

RESULTS

In an attempt to monitor early vein graft adaptation, serial graft surveillance by Duplex ultrasound scan was performed in a statistically valid subset of age-, sex-, and distal anastomotic site-matched patients with PAA and patients with occlusive disease (OD; n = 8 PAA; n = 8 OD). Compared with an age-matched and sex-matched cohort of patients (n = 60 grafts in each group) with occlusive disease and who had femoral below-knee bypass grafts (FBP) only, patients undergoing infrainguinal reconstruction for PAA had a higher 5-year primary graft patency (92% +/- 4% for PAA vs 66% +/- 7% for FBP; P <.01). Duplex surveillance demonstrated a progressive increase in arterialized vein graft diameter in the PAA group versus the OD group. In univariant analysis, aneurysmal disease was a significant predictor of final follow-up diameter (P =.002). In a linear regression model, controlling for diameter at first follow-up after bypass grafting, first follow-up diameter was also predictive of final follow-up diameter.

CONCLUSION

These data suggested altered remodeling of vein grafts in patients with popliteal artery aneurysm, which may have a beneficial effect on patency.

Portal venous system aneurysms: report of five cases

Until recently aneurysms in the portal venous system were considered to be very rare lesions. This opinion has largely been changed by the increasing number of cases reported in recent years. In this paper we report the cases of five patients with portal venous system aneurysms, including one with splenic vein aneurysm. One patient had associated portal hypertension. The reexamination of two patients 2 years later showed no change in the aneurysms. The sonographic features and related literature are reviewed. In the light of this series and the information in the literature, we recommend that portal venous system aneurysms should no longer be considered exceptionally rare entities.

A steady flow analysis on the stented and non-stented sidewall aneurysm models

As part of a general investigation on the effects of blood flow patterns in sidewall aneurysm, in vitro steady flow studies on rigid aneurysm models have been conducted using Particle Image Velocimetry over a range of Reynolds number from 200 to 1600. Above Reynolds number 700, one large recirculating vortex would be formed, occupying the entire aneurysmal pouch. The centre of the vortex is located at region near to the distal neck. A pair of counter rotating vortices would however be formed at Reynolds numbers below 700. For all the aneurysm models considered, the vortex strength, in general, is stronger at higher Reynolds numbers but lower at larger aneurysm size. Maximum strength of the vortex is about 15% of the bulk mean velocity in the upstream parent tube. Estimates of the wall shear stresses are derived from the near wall velocity measurements. Highest level of wall shear stresses always appears at the distal neck of the aneurysmal pouch. Stents and springs of different porosity have been used to dampen the flow movement inside the aneurysm so as to induce the possible formation of thrombosis. It is found that the flow movement inside the aneurysmal pouch can be suppressed to less than 5% of the bulk mean velocity by both devices. Furthermore, regions of high wall shear stresses at the distal neck could also be suppressed by almost 90%. The present results would be useful for further improvements in stent (or spring) technology.

Subclavian steal syndrome and flow-related aneurysm. Another reason to treat

A 48-year-old woman presented with a symptomatic right subclavian steal syndrome due to proximal subclavian artery stenosis. Anatomically the innominate artery was absent. Collateral circulation followed the vertebro-vertebral pathway with reversal of blood flow in the ipsilateral vertebral artery. There was also multiple dilated intervertebral collaterals and an associated saccular aneurysm on one of them. Surgical carotid-subclavian transposition permitted relief of clinical symptoms, disappearance of collateral circulation and subtotal regression of the aneurysm. This spontaneous evolution confirmed the role of high-flow in the pathogenesis of some aneurysms and the habitually good prognosis of flow-related aneurysms with correction of the cause. Arteriography still appears essential in diagnosis, pretherapeutic assessment and sometimes post-treatment evaluation in subclavian steal syndrome.

Healing mechanisms in experimental aneurysms. I. Vascular smooth muscle cells and neointima formation

PURPOSE

The purpose of this work is to better define healing phenomena in this model, in an effort to find strategies to improve long term results of endovascular treatment.

METHODS

Lateral wall venous pouch aneurysms were constructed on both carotid arteries in 30 pigs. The aneurysms were packed with collagen sponges per-operatively in 25 animals. Angiography, serial histological studies and immuno-histochemistry tests were used to study healing phenomena and measure neointima formation at various time intervals from 1 day to 9 weeks after surgery. GDC embolization was performed in 5 other pigs for comparison with the collagen sponge model. Explants from the neointima at the neck of aneurysms as well as from the parent artery of 8 pigs were prepared in an attempt to grow and to characterize in vitro cells responsible for healing porcine aneurysms using immunocytochemistry and enzymatic assays. To confirm the hypothesis that an analogy exists between cells involved in aneurysmal healing and neointimal cells found in restenosis, explant outgrowths were scored and compared to explants from intact carotid arteries and carotid arteries subjected to angioplasty in 3 other animals. In addition, to test the value of neointima measurements in quantifying results, 6 dogs were analysed to correlate the thickness of the neointima formed at the neck of aneurysms with angiographic results in animals prone to recurrences.

RESULTS

Histopathological findings with collagen sponge packing were similar to the ones following coil embolization. Porcine aneurysms had a strong tendency to heal with a thick neointima primarily composed of vascular smooth muscle cells (VSMCs). Aneurysms in dogs did not heal as well and the neointima at the neck of treated lesions was thin. Cells responsible for healing of experimental porcine aneurysms could be cultured in vitro, and are activated VSMCs. These cells, similar to those harvested following balloon injury, had a higher colony forming capacity and an accelerated explant outgrowth rate as compared to cells derived from the parent artery.

CONCLUSION

Animals which heal poorly harbor a thin or deficient neointima at the neck of treated aneurysms. Favorable healing in porcine aneurysms involves VSMCs which form a thick neointima. These VSMCs can be cultured in vitro. They share similar outgrowth characteristics with VSMCs recovered after balloon angioplasty. The collagen sponge model may be useful to harvest cells for in vitro experimentation and in the in vivo evaluation of the local delivery of potential therapeutic molecules thought to improve healing following embolization of aneurysms.

Aneurysm of the splenic artery

Splenic artery aneurysms, once considered rare entities are now being reported with increasing frequency. Due to a high incidence of fatal rupture, they are considered dangerous. Rupture is often the first and only symptom. With an increased index of suspicion and early aggressive treatment of asymptomatic splenic artery aneurysms, mortality has drastically decreased. We present a case of an unusually large asymptomatic aneurysm which was treated surgically, and discuss incidence, pathophysiology, clinical presentation, evaluation and treatment.

Peripheral and central colour contrast sensitivity in diabetes

PURPOSE

To study the influence of diabetes, with or without early retinopathy, on peripheral and central colour contrast sensitivity.

METHODS

The study included 32 patients with diabetes mellitus type II and 47 age-matched normals. The patients were divided into three sub-groups. 1. Diabetics with no retinopathy (on photographs or biomicroscopy). 2. Diabetics with microaneurysms only. 3. Diabetics with microaneurysms and hard exudates. Colour contrast sensitivity was measured with a computer graphics system along the protan, deutan and tritan axes.

RESULTS

The peripheral colour contrast thresholds were significantly elevated for all axes when comparing the group with microaneurysms and exudates to normals. There were also significant differences between the group with microaneurysms and hard exudates and the two other diabetic groups, respectively, but only for the tritan axis. Diabetics with no retinopathy or with microaneurysms only did not differ significantly from normals. The central colour contrast thresholds showed significant differences between normals and the group with microaneurysms, but only for the protan and deutan axes. There were significant differences for all three axes between normals and the group with microaneurysms and hard exudates. There were also significant differences between the group with microaneurysms and hard exudates and the two other diabetic groups, but only for the tritan axis. Diabetics with no retinopathy did not differ significantly from normals.

CONCLUSION

Peripheral colour contrast sensitivity was affected by low-grade diabetes type II retinopathy. This finding has to be considered if the method is to be used in screening for glaucoma. The central colour contrast sensitivity test seems to correlate to the degree of retinopathy and thereby perhaps provides a new screening method for diabetes retinopathy. Further studies are required in order to evaluate such a possibility.

Evaluation of intraaneurysmal blood velocity by time-density curve analysis and digital subtraction angiography

PURPOSE

Our purpose was to evaluate intraaneurysmal blood velocity by using time-density curve analysis and digital subtraction angiography.

METHODS

In 31 aneurysms, aneurysmal blood velocity was examined with digital subtraction angiography to determine mean transit time (MTF), peak density time (time to peak opacification) (PDT), and time to half-peak opacification (T1/2). Thirty frames per second were acquired, and the time-density curve was calculated. Regions of interest were drawn on the proximal parent artery, on the distal parent artery, and on the aneurysm itself.

RESULTS

There was no significant difference in MTT of blood velocity in the proximal site on the parent artery, in the distal site on the parent artery, and in the aneurysm. Similarly, there was no significant difference in PDT in the parent artery, in the distal site on the parent artery, and in the aneurysm; nor was there a significant difference in T1/2 in the parent artery, in the distal site on the parent artery, and in the aneurysm; that is, intraaneurysmal blood velocity was similar to that in the parent artery. PDT and T1/2 of small aneurysms were faster than that of large aneurysms; that is, blood velocity of small aneurysms was faster than that of large aneurysms.

CONCLUSION

Intraaneurysmal blood velocity in small aneurysms is similar to that in the parent artery; consequently, the central stream probably reaches the aneurysmal wall. Intraaneurysmal blood velocity in large aneurysms appears to be somewhat slower than that in small aneurysms.

[Multiple and de novo aneurysms in Ehlers-Danlos syndrome]

BACKGROUND AND PURPOSE

In 1964, the first case of "de novo" aneurysm has been reported by Graf and Hamby. The risk of late formation of aneurysm is unknown. Some factors could influence risk: history of hypertension, oral contraceptives, cigarette smoking. We report a rare case of "de novo" aneurysm associated with Ehlers-Danlos syndrome.

RESULTS

A 35-year-old female developed a subarachnoid hemorrhage (SAH). Angiography demonstrated 4 aneurysms. Five years before, she presented a SAH. At that time, four vessels angiography demonstrated only one PICA aneurysm. A Ehlers-Danlos syndrome was suspected, which was demonstrated on skin biopsies.

CONCLUSION

At our knowledge, this is the first case of "de novo" aneurysm associated with a Ehlers-Danlos syndrome.

Occlusive disease associated with popliteal aneurysms: impact on long term graft patency

OBJECTIVE

Correlate graft patency and limb salvage outcomes following popliteal aneurysm repair with the extent of tibial occlusive disease.

EXPERIMENTAL DESIGN

Retrospective study with a mean follow-up of 36 months (range, 2-96 months).

SETTING

Institutional teaching hospital.

PATIENTS

Of 20 popliteal aneurysms among 16 patients undergoing repair, 75% were associated with preoperative tibial vessel occlusion. Normal, three vessel infrapopliteal runoff was present in 5 patients, two vessels in 7 patients, and one or no vessels in 8 patients. Fifty percent of limbs were asymptomatic, while the remainder suffered from a variety of ischemic symptoms.

INTERVENTIONS

Eighteen of the 20 aneurysms were repaired with femoropopliteal bypass grafts, and two femoral-tibial bypasses were performed. Autogenous saphenous vein was used in 18 cases (10 in situ, 8 reversed) and PTFE in two short segment femoral-popliteal bypasses.

MEASURES

Graft patency was determined by presence of a palpable pulse, the re-establishment of normal ankle-brachial indices, or duplex scanning. Patency and limb salvage rates were estimated using life table analysis by the Kaplan-Meier method.

RESULTS

Preoperative symptoms did not correlate with tibial runoff, except in two patients presenting with acute thrombosis and ischemia. Cumulative graft patency by life table analysis was not different for either good (2-3 vessels, N-12) or poor (0-1 vessels, N-8) runoff. Overall primary patency at 60 months was 73%, and cumulative secondary patency was 100% with no limbs lost at 60 months.

CONCLUSIONS

Concomitant distal arterial occlusive disease is frequently associated with popliteal aneurysms, yet did not appear to substantially impact either long-term graft patency or limb salvage.

[Hemodynamic assessment of venous aneurysm of the lower leg and therapeutic consequences]

Based on the hemodynamic findings in patients with fusiform and saccular aneurysms, one can conclude that only cases with a saccular aneurysm will subsequently form parietal thrombi in the aneurysm that will bear the danger of pulmonary embolism. In fusiform aneurysms no disturbance of flow was noted. We have been comparing two patients from our institution with the current literature. As far as the treatment plan is concerned, it can be said that aneurysms with a history of thromboembolic complications and/or mural thrombi will undoubtedly be a strict indication for operative correction. The remainder of patients can be followed by means of color Doppler and duplex sonography.

Cerebrovascular disorders complicating pregnancy--beyond eclampsia

OBJECTIVE

Our purpose was to investigate the problems encountered in the diagnosis and management of cerebrovascular disorders associated with pregnancy and the puerperium.

STUDY DESIGN

Pregnancies complicated by cerebrovascular disorders were identified by retrospective chart review (1985 to 1995). Events associated with trauma, neoplasm, drug ingestion, and infection were excluded.

RESULTS

The study population comprised 24 women with a variety of cerebrovascular disorders: 14 with infarction (5 arterial, 9 venous), 6 with intracranial hemorrhage (3 anatomic malformation, 3 unknown etiology), 3 with hypertensive encephalopathy, and 1 with an unruptured aneurysm. Blood pressure reflected physical condition at presentation and did not predict diagnosis or outcome except in the 3 women with hypertensive encephalopathy. Only 4 of 14 women with infarction and 1 of 6 with intracranial hemorrhage had a diastolic blood pressure > or = 110 mm Hg. Presumption of eclampsia delayed the diagnosis in 10 women (41.7%). In addition, patient delay in seeking medical attention complicated 10 cases. After review, none of the adverse maternal outcomes were deemed preventable by earlier physician intervention. Seven maternal deaths occurred (29.2%). Neonatal outcome was related to the gestational age and the maternal condition at presentation.

CONCLUSION

Cerebrovascular disorders are an uncommon and unpredictable complication of pregnancy that are associated with substantial maternal and fetal mortality. Suspected eclampsia unresponsive to magnesium sulfate therapy warrants an immediate neuroimaging study. Interestingly, in women with intracranial hemorrhage, severe hypertension was not an associated predictive factor.

Modeling of flow in a straight stented and nonstented side wall aneurysm model

We investigated the changes of flow patterns in a blood vessel with a side wall aneurysm resulting from placement of a stent. Local hemodynamics can be markedly altered by placing an intravascular stent, which covers the orifice of the aneurysm. The alternations in flow patterns can lead to flow stasis in the aneurysmal pouch and promote the formation of a stable thrombus. Furthermore, a porous stent can serve as substrate for neointimal growth and subsequently induce a remodeling of the diseased arterial segment. To examine changes in local hemodynamics due to stent placement, a stented and nonstented aneurysm model was investigated computationally in a three-dimensional configuration using a finite element fluid dynamics program. The finite element model was studied under incompressible, pulsatile, viscous, Newtonian conditions. The fluid dynamic similarity parameter, i.e., the maximum/minimum Reynolds number, was set at about 240/25 based on cross-sectional average instantaneous flow. The Womersley number was set to 2.5. These values are representative of large cerebral arteries. The results of the stented versus the nonstented model show substantial difference sin flow patterns inside the aneurysmal pouch. Flow activity inside the stented aneurysm model is significantly diminished and flow inside the parent vessel is less undulated and is directed past the orifice. A high-pressure zone at the distal neck and the dome of the aneurysm prior to stenting decreases after stent placement. However, elevated pressure values are found at the stent filaments facing the current. Higher shear rates are observed at the distal aneurysmal neck after stenting, but are confined to a smaller region and are unidirectional compared to the nonstented model.

Traumatic aneurysm of the temporal artery: a report of five cases

Five cases of traumatic aneurysm of the superficial temporal artery are reported. Four patients clearly stated that they had sustained traumatic injuries within 3 months prior to the appearance of the pulsating aneurysms; in the remaining case, more than two years had passed before the appearance of the nodule, and it was without pulsation. Color Doppler echography was very useful for observing the circulation in these aneurysms. Histologically, these cases were pseudoaneurysms composed of small vessels with internal elastic lamina and adjacent connective tissue proliferation, suggesting a break in the arterial wall.