The endovascular treatment of cerebral arteriovenous aneurysms and malformations

Despite the progress made in cerebral aneurysm microneurosurgery, some morphologic and anatomic characteristics, or also clinical reasons, make surgical clipping of the aneurysmatic column difficult or unfeasible, justifying an endovascular therapeutic alternative. Despite the great progress made, the risk of endovascular intervention with microballoons is significant, particularly in the acute post-haemorrhagic phase: 17.9% mortality and 10.7% morbidity in endosaccular embolisation therapy with the detachable balloon maintaining the arterial lumen permeable. The use of the GDC system (Guglielmi Detachable Coil) has permitted the treatment of proximal and distal aneurysms in the carotid and vertebrobasilar arterial regions. Microcatheterisation also allows intravascular treatment of the vasospasm, by mechanical means--angioplasty, or by pharmacological vasodilatation. With the GDC system one can obtain a complete occlusion of small and medium aneurysms in over 85% of cases, definitive morbidity of 5% to 7% and mortality of 1% to 3%. The objective of AVM endarterial occlusions is to obliterate the nidus through the arterial pedicles that can be microcatheterised by means of a certain embolic agent (Cyanocrilate, PVA or other embolic products). Thus, it is possible to reduce the dimension of the nidus as well as diminish the severity of the arteriovenous shunt, later facilitating the operation or radiosurgery, with the possibility of complete surgical removal in 96% of patients after embolisation. The mortality directly related to this endovascular therapy is approximately 0.9% with severe morbidity below 2%. Complete obliteration of a cerebral AVM can be achieved with endovascular techniques in 15% to 20% of cases, particularly in small lesions, sustain AVMs require careful multidisciplinary discussion aimed at finding the best treatment for each case.     

Results of surgical treatment of ruptured abdominal aortic aneurysms

This paper analyzes results of 5-year surgical treatment of patients with ruptured abdominal aorta aneurysms (1991.-1995.) at the Clinic for Vascular and Transplantation Surgery of the Institute of Surgery in Novi Sad. 105 patients with abdominal aorta aneurysm underwent surgery, whereas in 31 patients there was a suspicion of rupture and it was confirmed by US and CT examination. One of basic factors to decrease mortality in these patients is early diagnosis and surgery before hemorrhagic shock occurs. Results in hemodynamic stabile patients with blood pressure over 100 mmHg and regular diuresis are much better with mortality of 20%. In order to estimate the correlation of hemodynamic state and outcome of the operation, patients were divided into three groups--hemodynamic stable with blood pressure over 100 mmHg and regular diuresis at admission: hemodynamic unstable patients with signs of mild or moderate shock and blood pressure under 100 mmHg and without initial diuresis which was regulated at the beginning of therapy and hemodynamic unstable patients in severe shock and unmeasurable blood pressure. The highest survival rate (10% mortality) and the least complications occurred in the first group of patients. The total mortality of patients after surgery was 48.48%. Timely diagnosis, suspicion of rupture and adequate first and with urgent transfer to a competent surgical institution are key factors in treatment of this disease and its outcome.     

Rupture during treatment of recently ruptured aneurysms with Guglielmi electrodetachable coils

BACKGROUND AND PURPOSE: We describe four cases of aneurysmal rupture during embolization with Guglielmi electrodetachable coils (GDCs) in an attempt to identify those aneurysms whose rupture during embolization represents a life-threatening risk; our emphasis is on emergency management, in particular, ventriculostomy. METHODS: Medical records were reviewed retrospectively for 91 aneurysms treated with GDCs 0 to 21 days after subarachnoid hemorrhage. Rupture was ascertained by the presence of extravascular effusion of contrast medium. RESULTS: Of the perforated aneurysms, two involved the anterior communicating artery, one the posterior inferior communicating artery, and one the basilar artery. Only two patients, whose aneurysms were located in the posterior fossa, had major complications (arterial hyperpressure, mydriasis, angiographically documented circulatory arrest or slowing). One of these patients died and the other improved after emergency ventriculostomy. CONCLUSION: Aneurysmal perforation during embolization may be accompanied by severe intracranial hypertension, which causes either a decrease or arrest of cerebral perfusion, the duration of which determines clinical outcome. Emergency ventriculostomy (which should be performed in the angiographic suite) is an effective means to reduce intracranial pressure. Recognition of aneurysms associated with a high risk of mortality by rupture in the course of embolization (recently ruptured small aneurysms, posterior fossa aneurysms, associated ventricular dilatation, massive cisternal hemorrhage) and use of proper logistics should ensure the effective management of this devastating complication.     

Endovascular treatment of ruptured posterior circulation aneurysms using electrolytically detachable coils

The murine interleukin-7 (IL-7) gene was disrupted to examine the role of IL-7 in the lymphoid system. Expansion of lymphoid cells is sharply curtailed in IL-7-deficient mice. This is evident in a dramatic reduction but not elimination of lymphoid cells in the thymus, bone marrow and spleen. The few thymocytes present express CD4 and/or CD8 markers associated with T-cell maturation. Similarly, a limited number of B cells detected in the bone marrow rearrange and express immunoglobulin genes. Small but distinct populations of B and T cells are found in the spleens of IL-7-deficient mice. Thus the signal transmitted by IL-7 plays a central role in the expansion of lymphocytes while it is not absolutely required for their maturation. A transgene that directs expression of IL-7 to lymphoid cells was found to restore the numbers of thymocytes, bone marrow B-cell progenitors and splenic lymphocytes of IL-7-deficient mice to approximately normal levels. This genetic complementation confirms that the lymphoid defect is specifically due to the absence of IL-7 and demonstrates that the expansion of lymphoid cells in an organism is regulated by their exposure to IL-7.     

Saccular intracranial aneurysms: endovascular treatment with mechanical detachable spiral coils

PURPOSE: To evaluate endovascular treatment of saccular intracranial aneurysms with mechanical detachable spiral coils. MATERIALS AND METHODS: Fifty-three patients with 56 saccular aneurysms underwent endovascular treatment with spiral coils. All but five had symptomatic subarachnoid hemorrhage staged according to the Hunt and Hess classification as follows: stage IV or V (n = 20), stage III (n = 10), stage I or II (n = 20), and stage 0 (asymptomatic [n = 6]). RESULTS: Forty-seven aneurysms were occluded (100% occlusion) on follow-up angiograms with the following time distribution: 24 months for six aneurysms (six patients), 12 months for 14 aneurysms (11 patients), 6 months for 13 aneurysms (13 patients), 4 months for four aneurysms (four patients), and only immediate postprocedure study for 16 aneurysms (16 patients) (excludes two deaths and one failure). CONCLUSION: In this relatively small group, endovascular treatment with mechanical detachable spiral coils had a success rate of 90%, and it appears to be a rapid, reliable, and relatively safe technique in the treatment of life-threatening subarachnoid hemorrhage.     

Future endovascular management of cerebral aneurysms

The endovascular management of cerebral aneurysms is undergoing revolutionary growth. Recent advances in endovascular surgery including balloon remodeling, revascularization techniques, functional cerebral rearrangement, intracranial stents, treatment for vasospasm and coil design are discussed, as are their future considerations.     

Embolization for ruptured superior mesenteric artery aneurysms

Superior mesenteric artery (SMA) aneurysms are very uncommon. They are difficult to detect until they rupture and cause hypovolaemic shock. We performed embolization in four cases of aneurysm of branches of the superior mesenteric artery, succeeding in three cases without the need for surgical treatment. In the first case, the aneurysm was excised because of migration of a microcoil into the left hepatic artery. It was not retrieved because sufficient blood flow to the liver was shown on angiography after migration and no ischaemic change of liver was detected on laparotomy. In the second case, the aneurysm arose from the anterior pancreaticoduodenal artery. In the third case, the patient had two SMA aneurysms; one had been resected at surgery, another was revealed on follow-up angiography and embolized with microcoils. The fourth patient had a jejunal artery aneurysm with extravasation; haemostasis was achieved by packing it. In all four cases, no major complications were observed in the clinical course after embolization. Microcoils were considered to be the desirable embolic material, in order to prevent post-therapeutic ischaemic change. Embolization should be the treatment of choice for SMA aneurysms, because it is less invasive and takes less time than surgical treatment.     

Initial experience with collagen-filled Guglielmi detachable coils for endovascular treatment of experimental aneurysms

PURPOSE: To evaluate the effectiveness of Guglielmi detachable coils (GDCs) filled with collagen threads in the permanent treatment of experimental aneurysms. METHODS: Seventeen side-wall aneurysms were surgically constructed in the canine common carotid artery; six were treated with conventional GDCs and 11 with collagen-filled GDCs. One aneurysms was removed at 1 week, the others were studied by digital subtraction angiography for a period of 8 to 12 weeks. Longitudinal sections of all aneurysms were examined by light microscopy. RESULTS: Angiograms obtained throughout the follow-up period showed no significant difference between aneurysms treated with conventional GDCs and those treated with collagen-filled GDCs. Light microscopy revealed a dense meshwork of newly formed collagen and fibroblasts near the collagen-filled GDCs, whereas a loose cellular meshwork surrounded the conventional GDCs at 8 and 12 weeks after treatment. CONCLUSION: Collagen threads within GDCs do not noticeably improve angiographic treatment of experimental aneurysms; however, these threads did induce local proliferation of fibroblasts and production of collagen within the aneurysmal cavities.     

Results and complications after endovascular reconstruction of aortic aneurysms

Between August 1994 and December 1996 137 patients (10 female and 127 male, mean age 66 yrs., range 27-85) with aortoiliac aneurysmal disease were treated with endovascular stent grafts. Pathology included 5 thoracic, 131 abdominal and 1 isolated iliac artery aneurysm. 88 straight tube grafts (75 Mintec, 12 EVT, 1 Chuter) and 43 bifurcated grafts (21 Mintec, 20 EVT, 2 Chuter) were implanted in the infrarenal aorta. 5 (Mintec) tube grafts were used for the thoracic aneurysms. One tapered tube graft was used to exclude the isolated iliac aneurysm. 11 patients (8%) required conversion to open surgical repair. This was due to defective devices in 5, device related occlusion of a renal artery in 2, aortic dissection in 1, occlusion of iliac outflow in 1, a large unmanageable proximal endoleak in 1 and a retroperitoneal bleeding resulting in hemorrhagic shock in 1 patient. There was one procedure related death for a mortality of 0.7%. Patients were followed every 3-6 months using CT with i.v. contrast and ultrasound duplex examinations with adjunctive usage of an intravenous ultrasound contrast agent (Levovist, Schering AG). Intraarterial DSA was used only when called for by thrombotic or stenotic complications. At a mean follow-up of 9.2 months (range 2-24 months) 16 (17%) primary and 8 (8.5%) secondary leaks (at the distal anchoring zone) were detected after implantation of tube grafts. 11 (25.6%) leaks were detected after implantation of bifurcated grafts. Iliac artery occlusion was observed in 2 patients after placement of a straight endograft, 6 times after reconstruction with a Mintec bifurcated device and 3 times after implantation of an EVT bifurcated endograft. Successful treatment of iliac artery occlusion without the need for subsequent amputation or major disability included extraanatomic bypass in 7 patients, PTA (3 patients) and implantation of wallstents (2 patients) or conservative management (1 patient).     

Percutaneous endovascular stent-graft repair of iliac artery aneurysms

There has been a tremendous explosion in the area of DNA vaccine research over the last 4 years, particularly in relation to antiviral vaccines. This report discusses the development and application of this new technology with regard to parasitic infections. Progress has been made towards the development of a vaccine against malaria, cryptosporidiosis, leishmaniasis, toxoplasmosis and schistosomiasis. In the future, nucleic acid vaccines will be a useful tool to help control these and other parasitic infections.     

Complex intracranial aneurysms: combined operative and endovascular approaches

OBJECTIVE: Endovascular management of complex intracranial aneurysms is increasingly being considered as an alternative to standard surgical clipping. However, little attention has been paid to the complementary nature of surgery and endovascular therapy. METHODS: Between September 1992 and May 1997, 12 patients with complex intracranial aneurysms were treated with combined operative and endovascular methods. Seven patients demonstrated subarachnoid hemorrhage (two of Grade II, two of Grade III, and three of Grade IV). Five patients demonstrated unruptured aneurysms, i.e., three giant aneurysms (one vertebrobasilar junction aneurysm, one middle cerebral artery bifurcation aneurysm, and one internal carotid artery-ophthalmic artery aneurysm), one large internal carotid artery-ophthalmic artery aneurysm, and one middle cerebral artery serpentine aneurysm. Management strategies involved either surgery followed by endovascular therapy (S-E; n = 5) or endovascular therapy followed by surgery (E-S; n = 7). S-E paradigms included aneurysm exploration followed by endovascular treatment (S-E1; n = 3), partial aneurysm clipping followed by endovascular aneurysm packing (S-E2; n = 1), and extracranial-to-intracranial bypass followed by endovascular parent vessel occlusion (S-E3; n = 1). E-S paradigms included superselective angiography followed by surgical clipping (E-S1; n = 2), Guglielmi detachable coil partial dome packing followed by delayed surgical clipping (E-S2; n = 2), proximal temporary vessel balloon occlusion followed by aneurysm clipping (E-S3; n = 2), and proximal permanent vessel occlusion followed by surgical aneurysm decompression for mass effect treatment (E-S4; n = 1). RESULTS: Eleven aneurysms (92%) were completely eliminated. The remaining aneurysm was 90% obliterated and remained quiescent at the 34-month follow-up examination, despite presenting with subarachnoid hemorrhage. No patient experienced repeat bleeding (follow-up period, 23+/-28 mo). There were no deaths. One patient achieved a fair outcome (Glasgow Outcome Scale score of III); all other patients experienced excellent outcomes (Glasgow Outcome Scale score of I). In all cases, the aneurysm management paradigm chosen had a positive effect on definitive therapy. CONCLUSION: Several factors can contribute to the complexity of intracranial aneurysms. Management strategies that combine operative and endovascular techniques in a complementary way, for the best possible outcomes for these patients, can be designed accordingly.     

Endoleaks after endovascular graft treatment of aortic aneurysms: classification, risk factors, and outcome

PURPOSE: Incomplete endovascular graft exclusion of an abdominal aortic aneurysm results in an endoleak. To better understand the pathogenesis, significance, and fate of endoleaks, we analyzed our experience with endovascular aneurysm repair. METHODS: Between November 1992 and May 1997, 47 aneurysms were treated. In a phase I study, patients received either an endovascular aortoaortic graft (11) or an aortoiliac, femorofemoral graft (8). In phase II, procedures and grafts were modified to include aortofemoral, femorofemoral grafts (28) that were inserted with juxtarenal proximal stents, sutured endovascular distal anastomoses within the femoral artery, and hypogastric artery coil embolization. Endoleaks were detected by arteriogram, computed tomographic scan, or duplex ultrasound. Classification systems to describe anatomic, chronologic, and physiologic endoleak features were developed, and aortic characteristics were correlated with endoleak incidence. RESULTS: Endoleaks were discovered in 11 phase I patients (58%) and only six phase II patients (21%; p < 0.05). Aneurysm neck lengths 2 cm or less increased the incidence of endoleaks (p < 0.05). Although not significant, aneurysms with patent side branches or severe neck calcification had a higher rate of endoleaks than those without these features (47% vs 29% and 57% vs 33%, respectively), and patients with iliac artery occlusive disease had a lower rate of endoleaks than those without occlusive disease (18% vs 42%). Endoleak classifications revealed that most endoleaks were immediate, without outflow, and persistent (71% each), proximal (59%), and had aortic inflow (88%). One patient with a persistent endoleak had aneurysm rupture and died. CONCLUSIONS: Endoleaks complicate a significant number of endovascular abdominal aortic aneurysm repairs and may permit aneurysm growth and rupture. The type of graft used, the technique of graft insertion, and aortic anatomic features all affect the rate of endoleaks. Anatomic, chronologic, and physiologic classifications can facilitate endoleak reporting and improve understanding of their pathogenesis, significance, and fate.     

Anatomical and morphological factors correlating with rupture of intracranial aneurysms in patients referred for endovascular treatment

Ambulatory blood pressure (ABP) measurements were performed in a Danish population of 295 males and 275 females aged 19-21 years. Individualised day and night periods were defined from the subjects own recording of bedtime and rising on the day of their ABP measurements. During these individualised periods the ABP values for daytime, night-time and for the whole 24-h period were measured. The mean +/- s.d. values for systolic/diastolic ABP for the whole population were (124+/-11)/(70+/-7) mm Hg in the daytime, (106+/-12)/(60+/-9) mm Hg in the night-time, and (120+/-11)/(68+/-7) mm Hg in the whole 24-h period. Males had a mean systolic ABP of 9 mm Hg and mean diastolic ABP of 5 mm Hg higher than females. In males mean +/- s.d. systolic/diastolic ABP values in the daytime were (129+/-10)/(73+/-7) mm Hg, in the night-time (111+/-12)/(63+/-8) mm Hg, and in the whole 24-h period (125+/-10)/(71+/-7) mm Hg. The corresponding values in females were (119+/-10)/(68+/-6) mm Hg, (103+/-11)/(57+/-8) mmHg, and (115+/-10)/(66+/-6) mm Hg, respectively. In conclusion this study provides sex-specific normal values for ABP in a 19 to 21-year-old age group based on individualised daytime and night-time periods.     

Anatomical suitability of abdominal aortic aneurysms for endovascular repair

BACKGROUND: Aortic aneurysm anatomy is crucial when considering patients for endovascular repair. The aim of this study was to determine the proportion of patients with aortic aneurysm suitable for endovascular repair with three different graft-stent systems. METHODS: Spiral computed tomographic angiography was used to assess the anatomy of 154 abdominal aortic aneurysms. Measurements were made of aneurysm neck length and diameter, renal artery to aortic bifurcation length, common iliac artery diameter and length, and external iliac artery diameter. Aneurysms were assessed for anatomical suitability for currently available aortoaortic, aortobi-iliac and aortouni-iliac devices. RESULTS: Six patients (4 per cent) had a distal aortic neck suitable for implantation of a straight aortic graft. Fifteen patients (10 per cent) had arterial anatomy suitable for implantation of a bifurcated graft and 85 (55 per cent) patients were suitable for endovascular repair with an aortouni-iliac graft. The primary reasons for unsuitability were: proximal neck length less than 1.5 cm (44 patients), proximal neck diameter greater than 3.0 cm (12), and angulation of the proximal neck (three). A further ten patients were considered unsuitable for an aortouni-iliac graft because of bilateral common iliac artery aneurysms (four), tortuous iliac arteries (four) and narrow external iliac arteries (two). CONCLUSION: The aortouni-iliac device has the widest applicability of the currently available endovascular systems but open repair remains the only option for a large proportion of patients.     

Learning disorders after ruptured aneurysms of the anterior communicating artery

The aim of this study was to reevaluate short term and long term memory disorders after anterior communicating artery rupture, then to more specifically assess the importance and the role of forgetting, proactive and retroactive interferences, impaired memory for temporal order, attention disorders and dysexecutive syndrome, and finally MRI-defined brain lesions. Twenty one patients presenting with selective anterior brain injury, were assessed at the secondary and late post stroke phases. The short term memory analysis showed the digit span was reduced at the secondary stage, but that mean performances were preserved in the Peterson and Sternberg paradigms. Verbal and visuospatial learning in long term memory showed a severe deficit in free recall, chiefly serial, and associative recall. Recognition was mildly impaired at the secondary phase, and later normalized. A definite and lasting increase of proactive and retroactive interferences and an impairment in discriminating the temporal order of word presentations were observed. Amnesic impairment was relatively well correlated with forgetting, severity of interferences and temporal order amnesia, so as with disorders of attention and executive functions (Wisconsin Card Sorting Test). However, intrusions in free recall and false recognitions were not clearly related with the dysexecutive syndrome. The severity of amnesia was associated with lesions of the left anterior cingulate cortex, and of the corpus callosum. These results suggest that these patients mainly had a deficit in information retrieval, mostly compromising long term memory, but also to a lesser degree short term memory. Forgetting, interferences and the dysexecutive syndrome probably play an important role in the decline of mnemonic performance, but do not clearly explain intrusions in recall and errors in recognition.     

Isoenzyme analysis of hyperamylasaemia associated with ruptured abdominal aortic aneurysms

Hyperamylasaemia may occur following abdominal aortic aneurysm rupture and its use as a prognostic indicator has been suggested. However, the isoenzyme responsible for the rise in serum amylase has not been investigated. In this study, isoenzyme analysis was performed on the serum of patients noted to have a raised amylase from their routine biochemistry samples. Individual cases were then reviewed regarding clinical course and outcome. The pancreas has been thought to be the predominant source of the observed hyperamylasaemia. However, in this study a mixed picture of pancreatic and salivary isoenzymes was found. Of the four highest recorded amylase levels two were salivary in origin, one pancreatic and one mixed. The highest recorded amylase level was of salivary origin in a patient that survived without any major complication. The four patients that died all showed evidence of gut infarction/ischaemia. Two had hyperamylasaemia of a mixed pattern, one pancreatic and one of salivary origin.     

Long-term survival and late complications after repair of ruptured abdominal aortic aneurysms

PURPOSE: Long-term survival and late vascular complications in patients who survived repair of ruptured abdominal aortic aneurysms (RAAA) is not well known. The current study compared late outcome after repair of RAAA with those observed in patients who survived elective repair of abdominal aortic aneurysms (AAA). METHODS: The records of 116 patients, 102 men and 14 women (mean age: 72.5 (8.3 years), who survived repair of RAAA (group I) between 1980 to 1989 were reviewed. Late vascular complications and survival were compared with an equal number of survivors of elective AAA repair matched for sex, age, surgeon, and date of operation (group II). Survival was also compared with the age and sex-matched white population of west-north central United States. RESULTS: Late vascular complications occurred in 17% (20/116) of patients in group I and in 8% (9/116) in group II. Paraanastomotic aneurysms occurred more frequently in group I than in group II (17 vs. 8, p = 0.004). At follow-up, 32 patients (28%) were alive in group I (median survival: 9.4 years) and 53 patients (46%) were alive in group II (median survival: 8.7 years). Cumulative survival rates after successful RAAA repair at 1, 5, and 10 years were 86%, 64%, and 33%, respectively. These were significantly lower than survival rates at the same intervals after elective repair (97%, 74%, and 43%, respectively, p = 0.02) or survival of the general population (95%, 75%, and 52%, respectively, p < 0.001). Coronary artery disease was the most frequent cause of late death in both groups. Vascular and graft-related complications caused death in 3% (3/116) in group I and 1% (1/116) in group II. Cox proportional hazards modeling identified age (p = 0.0001), cerebrovascular disease (p = 0.009), and number of days on mechanical ventilation (p = 0.01) to be independent prognostic determinants of late survival in group I. CONCLUSIONS: Late vascular complications after repair of RAAA were higher and late survival rates lower than after elective repair. These data support elective repair of AAA. As two-thirds of the patients discharged after repair of RAAA are alive at 5 years, aggressive management of RAAA remains justified.