Marc R.H.M. van Sambeek

Endovascular versus Conventional Open Repair of Acute Abdominal Aortic Aneurysm: Feasibility and Preliminary Results

PURPOSE To evaluate the feasibility of endovascular treatment of acute abdominal aortic aneurysm (AAA) with commercially prepared bifurcated systems. METHODS From January through July 2001, 22 patients (17 men; mean age 73.6 years, range 59-89) were referred with an acute (symptomatic/ruptured) AAA. Six patients were treated with emergent open surgery because of hemodynamic instability, but the other 16 patients underwent computed tomographic angiography with multidirectional reconstruction. Six (27%) aneurysms were suitable for endovascular repair (EVR) and were successfully treated. Procedural variables, morbidity, and mortality were compared between the EVR group and 6 patients of equivalent hemodynamic status from among the conventionally treated patients. RESULTS There was no mortality in either group. The median aneurysm diameter in the EVR group was 63 mm (range 48-84) versus 80 mm (45-82) in the matched surgically treated AAAs (p=0.628). Procedural duration was 193 minutes (150-265) for the EVR group compared to 203 minutes (130-270) for the matched group (p=0.630). Median blood loss was significantly less (p=0.010) in the EVR group (125 versus 3400 mL). Median length of stay (LOS) in intensive care was 8 hours (0-21) versus 62 hours (48-112) for the surgical group (p=0.004). Hospital LOS was significantly reduced (p=0.024) for the EVR patients (7.5 [2-16] versus 15.5 [10-34] days). CONCLUSIONS Endovascular treatment of acute aneurysm is feasible, and preliminary results are promising.

Accurate assessment of abdominal aortic aneurysm with intravascular ultrasound scanning: Validation with computed tomographic angiography☆☆☆★

PURPOSE The purpose of this study was to assess the accuracy of intravascular ultrasound (IVUS) parameters of abdominal aortic aneurysm, used for endovascular grafting, in comparison with computed tomographic angiography (CTA). METHODS This study was designed as a descriptive study. Between March 1997 and March 1998, 16 patients with abdominal aortic aneurysms were studied with angiography, IVUS (12.5 MHz), and CTA. The length of the aneurysm and the length and lumen diameter of the proximal and distal neck obtained with IVUS were compared with the data obtained with CTA. The measurements with IVUS were repeated by a second observer to assess the reproducibility. Tomographic IVUS images were reconstructed into a longitudinal format. RESULTS IVUS results identified 31 of 32 renal arteries and four of five accessory renal arteries. A comparison of the length measurements of the aneurysm and the proximal and distal neck obtained with IVUS and CTA revealed a correlation of 0.99 (P <.001), with a coefficient of variation of 9%. IVUS results tended to underestimate the length as compared with the CTA results (0.48 +/- 0.52 cm; P <.001). A comparison of the lumen diameter measurements of the proximal and distal neck derived from IVUS and CTA showed a correlation of 0.93 (P <.001), with a coefficient of variation of 9%. IVUS results tended to underestimate aneurysm neck diameter as compared with CTA results (0.68 +/- 1.76 mm; P =.006). Interobserver agreement of IVUS length and diameter measurements showed a good correlation (r = 1.0; P <.001), with coefficients of variation of 3% and 2%, respectively, and no significant differences (0.0 +/- 0.16 cm and 0.06 +/- 0.36 mm, respectively). The longitudinal IVUS images displayed the important vascular structures and improved the spatial insight in aneurysmal anatomy. CONCLUSION Intravascular ultrasound scanning results provided accurate and reproducible measurements of abdominal aortic aneurysm. The longitudinal reconstruction of IVUS images provided additional knowledge on the anatomy of the aneurysm and its proximal and distal neck.

The Carotid Body Tumor

A 63-year old female was referred to our hospital because she had a mass on the right side of the neck. The swelling had slowly progressed in a couple of months. Besides problems with swallowing there were no other complaints. Her previous medical history was unremarkable and she could not remember any family members with similar lesions. Physical examination showed a non-tender mass with a diameter of around 6 cm located just anterior of the sternocleidomastoid muscle in the anterior triangle of the neck. The mass was mobile in a back-forward direction but could not be moved in a cranial-caudal direction. No signs of cranial nerve deficits were detected. An ultrasound examination showed a highly vascularized structure in the bifurcation between the internal and external carotid artery (Fig. 33.1).

Endoscopic aneurysm sac fenestration as a treatment option for growing aneurysms due to type II endoleak or endotension

Purpose: To evaluate endoscopic fenestration as a treatment option for growing aneurysm due to a type II endoleak or endotension after endovascular aneurysm repair (EVAR). Methods: Eight patients (7 men; median age 69 years, range 55–79) who underwent “successful” EVAR were diagnosed with a growing aneurysm due to a type II endoleak (n = 4) or endotension (n=4). Surgical intervention consisted of endoscopic fenestration of the sac and removal of all the thrombus material, preceded by clipping of the inferior mesenteric and all lumbar arteries in cases of endoleak. Fluid samples from the fenestrated aneurysm sac were analyzed for the presence of microorganisms and fibrin degradation products (FDP) and/or D-dimers. Results: The median duration of operation was 220 minutes (range 111–333). There was no perioperative mortality. In one patient, the endoscopic procedure was converted to an open fenestration procedure. Seven patients had uncomplicated follow-up and a clear decrease in the diameter of the sac; one patient was converted to open repair owing to continued sac growth despite fenestration. Bacterial cultures were negative in all patients, but high levels of FDP and/or D-dimers were found in all available samples, indicating continued fibrinolysis. Conclusion: Endoscopic fenestration, with or without endoscopic clipping of all side branches, seems to be an effective, reliable and minimally invasive treatment option for patients with a growing aneurysm due to type II endoleak or endotension. The high levels of FDP and/or D-dimers in the aneurysm sac are suggestive of hyperfibrinolysis, which may play an important role in aneurysm growth after EVAR.

Endovascular Repair of an Extracranial Internal Carotid Artery Aneurysm Complicated by Heparin-Induced Thrombocytopenia and Thrombosis

Purpose: To report the endovascular treatment of a symptomatic extracranial internal carotid artery (ICA) aneurysm that was complicated by heparin-induced thrombocytopenia and thrombosis. Methods and Results: After undergoing a coronary artery bypass graft procedure, a patient was diagnosed with a symptomatic, 3.5-cm ICA aneurysm by computed tomography and angiography. Via a semiclosed access, an Enduring vascular graft was inserted under controlled back bleeding from the ICA. The patient was recovering uneventfully when routine duplex scanning on the fifth postoperative day suggested multiple thrombi within the graft, which was confirmed by arteriography. Thrombectomy and local fibrinolysis were performed; however, the graft occluded the next day without causing neurological symptoms. Heparin-induced thrombocytopenia was diagnosed by enzyme-linked immunosorbent assay. Conclusions: Endovascular repair of high cervical extracranial ICA aneurysms is feasible, and protection against intracerebral embolization can be achieved using a semiclosed technique with controlled back bleeding from the ICA during endograft deployment. However, multiple thrombi or thrombotic occlusion during the postoperative period, particularly in a patient already sensitized to heparin, should direct attention toward possible heparin-induced thrombocytopenia.

Thrombolysis of Occluded Synthetic Bypass Grafts in the Lower Limb: Technical Success and 1-Year Follow-up in 32 Patients

Purpose: To evaluate prospectively the technical success and clinical outcome of thrombolysis for acute occlusion of synthetic arterial bypass grafts in the lower limb. Methods: Thirty-two consecutive patients (27 men; median age 65 years, range 41–80) with occluded polytetrafluoroethylene bypass grafts were treated with direct-catheter thrombolysis (100,000-IU bolus of urokinase with 100,000-IU/h infusion) followed by ancillary interventions to treat underlying stenosis whenever necessary. All patients received oral anticoagulation to maintain the international normalized ratio at 3.0 to 4.0. Clinical follow-up and duplex ultrasound examinations were performed at 3-month intervals up to 1 year. Results: Thrombolysis was technically successful in 27 (84%) patients; 3 of the 5 failed patients had amputations. Mean duration of urokinase therapy was 36±14 hours. In 18 patients, underlying stenoses (11 distal anastomosis, 5 proximal anastomosis, and 3 inflow) were treated, 15 by an endovascular procedure and 3 surgically. Four major complications occurred: groin hematoma, sepsis, transient renal dysfunction, and a hemorrhage at the proximal anastomosis after urokinase treatment. At 1 year, 21 bypass grafts had reoccluded (20% patency rate on intention-to-treat basis); 3 reocclusions resulted in amputation (overall 19% amputation rate). Conclusions: Thrombolysis in the setting of acute lower limb bypass graft occlusion is associated with good initial technical success rates and satisfactory clinical results. However, the re-occlusion rate within 1 year is high.

Comparison of catecholamine hormone release in patients undergoing carotid artery stenting or carotid endarterectomy.

Purpose: To investigate the pattern of catecholamine response in patients undergoing carotid endarterectomy (CEA) or carotid artery stenting (CAS). Methods: Adrenaline, noradrenaline, and renin levels were measured at 5 time points in 12 patients undergoing 13 CEAs (1 bilateral) and 13 patients undergoing unilateral CAS. Arterial blood samples were taken at the following time points: (1) after induction in CEA patients or 5 minutes following first contrast injection in CAS patients, (2) 5 minutes following ICA clamp release in surgical patients or deflation of the balloon in the CAS cohort, (3) 60 minutes following ICA clamp release in surgical patients or deflation of the balloon in the CAS cohort, and (4) 24 hours following the procedure. Intraoperative blood pressure and heart rate were recorded using radial arterial monitoring. Changes in adrenaline, noradrenaline, and renin levels are expressed as ratios versus baseline. Results: Patterns of adrenaline and noradrenaline release were significantly different in patients undergoing CAS and CEA, with much higher and more variable surges of adrenaline and noradrenaline occurring in CEA patients. Adrenaline and noradrenaline levels increased significantly over baseline following carotid artery clamping in patients undergoing CEA (noradrenaline ratio before clamping: 1.54±1.25, 24 hours after unclamping: 8.38±16.35 [p<0.001]; adrenaline ratio before clamping: 1.12±0.49, 60 minutes after unclamping: 17.59± 19.14 [p<0.001]). Conversely, in patients undergoing CAS, catecholamine levels remained unchanged (noradrenaline ratio before dilation: 0.96±0.23, 24 hours after the procedure: 0.92±0.32 [p = NS]; adrenaline ratio before dilation: 0.83±0.33, 60 minutes after balloon deflation: 0.56±0.32 [p = NS]). Conclusions: CAS is associated with a significantly less marked catecholamine response than CEA, which may reflect down-regulation of the sympathetic nervous system in response to carotid sinus stimulation during carotid angioplasty.

Local anisotropic mechanical behavior of human carotid atherosclerotic plaques : characterization using indentation test and inverse finite element analysis

Atherosclerosis is a disorder of the arterial wall. The vessel wall is invaded by lipids and inflammatory cells which can lead to thickening of the arterial wall and eventually to formation of a vulnerable atherosclerotic plaque. Such a vulnerable plaque consists of intraplaque hemorrhage, inflammatory cells, a lipid rich necrotic core (LRNC) and a thin fibrous cap separating the thrombogenic LRNC from the blood stream. The thin fibrous cap is prone to rupture, which can cause thrombus formation and subsequent embolization of thrombus into distal vessels or acute occlusion. This is the major cause of stroke and myocardial infarction.Copyright

What Vascular Surgeons Want from Vascular Ultrasound

“Endovascular surgery” has emerged from the interest in minimal invasive surgery. The collaboration between cardiologists, interventional radiologists and vascular surgeons has been of eminent importance for the evolution of endovascular techniques. The development of endovascular techniques prompted the need for improved vascular imaging and better diagnostics. Angiography displays only a ‘lumenogram’ of the vessel. Color flow duplex, computed tomographic angiography and magnetic resonance imaging are important in the pre- and postintervention assessment of vascular disease, however, in smaller peripheral vessels, these techniques do not always give accurate information on the dimensions of the vessel and the extent of the disease. In contrast, intravascular ultrasound (IVUS) provides histology-like cross-sections of the blood vessel, allowing qualitative evaluation of plaque composition and mural thrombus and quantitative assessment of lumen area, vessel area and plaque area.