Spectral CT of carotid atherosclerotic plaque: comparison with histology.

OBJECTIVE: To distinguish components of vulnerable atherosclerotic plaque by imaging their energy response using spectral CT and comparing images with histology. METHODS: After spectroscopic calibration using phantoms of plaque surrogates, excised human carotid atherosclerotic plaques were imaged using MARS CT using a photon-processing detector with a silicon sensor layer and microfocus X-ray tube (50 kVp, 0.5 mA) at 38-µm voxel size. The plaques were imaged, sectioned and re-imaged using four threshold energies: 10, 16, 22 and 28 keV; then sequentially stained with modified Von Kossa, Perl's Prussian blue and Oil-Red O, and photographed. Relative Hounsfield units across the energies were entered into a linear algebraic material decomposition model to identify the unknown plaque components. RESULTS: Lipid, calcium, iron and water-like components of plaque have distinguishable energy responses to X-ray, visible on spectral CT images. CT images of the plaque surface correlated very well with histological photographs. Calcium deposits (>1,000 µm) in plaque are larger than iron deposits (<100 µm), but could not be distinguished from each other within the same voxel using the energy range available. CONCLUSIONS: Spectral CT displays energy information in image form at high spatial resolution, enhancing the intrinsic contrast of lipid, calcium and iron within atheroma. KEY POINTS: Spectral computed tomography offers new insights into tissue characterisation. Components of vulnerable atherosclerotic plaque are spectrally distinct with intrinsic contrast. Spectral CT of excised atherosclerotic plaques can display iron, calcium and lipid. Calcium deposits are larger than iron deposits in atheroma. Spectral CT may help in the non-invasive detection of vulnerable plaques.

Endovascular repair of the thoracic aorta: predictors of 30-day mortality in patients on the New Zealand Thoracic Aortic Stent Database (NZ TAS).

OBJECTIVES: To evaluate data in the New Zealand Thoracic Aortic Stent database to try and identify a scoring system that could predict 30-day mortality in patients undergoing stenting of the descending thoracic aorta (TEVAR). DESIGN: Retrospective analysis of the New Zealand thoracic aortic stent database between December 2001 and August 2007. MATERIALS AND METHODS: The 30-day mortality of the 122 patients is 7.38% (n=9). Risk factors were recorded based on the Society of Thoracic Surgeons (STS) risk score. Glasgow aneurysm score was calculated and the pathology being treated analysed. Univariate analysis was carried out. RESULTS: The mortality of three pathology groups was compared. 30-day mortality was 2.04% (n=1) in the elective aneurysm group, 17.95% (n=7) in the complicated Stanford type B dissection group, and 0% (n=0) in the trauma group. Thirty-day mortality is significantly higher in the dissection group compared with the elective aneurysm (p=0.02) and trauma (p=0.03) groups. The most frequent risk factors in the dissection group of patients were peripheral vascular disease, smoking and hypertension. Although percentage mortality is higher with increasing GAS, the results are not statistically significant (p=0.34). No independent risk factors were identified from the STS risk score data. CONCLUSION: No specific risk score system seems to be able to predict mortality in TEVAR patients.

Outcomes of endovascular repair of acute thoracic aortic injury: interrogation of the New Zealand thoracic aortic stent database (NZ TAS).

OBJECTIVES: Report the New Zealand national experience of endovascular repair of acute traumatic thoracic aortic injuries (TTAIs). DESIGN: Retrospective analysis of the New Zealand thoracic aortic stent database between December 2001 and December 2007. MATERIALS AND METHODS: Of the 134 patients on the database, 27 patients (20%) underwent endovascular repair of TTAI. Data collected included age, sex, cause of injury, details of the procedure, complications and mortality. RESULTS: Most patients were young, median age 20 (15-78), male (n=19, 70%), and involved in motor vehicle accidents (n=23, 85%). Median length of aorta stented was 117 mm (77-200 mm). Great vessel origins were covered intentionally in 23 (85%) patients, four (17%) requiring a hybrid procedure. Average procedure time was 98.3 min (35-180). Primary technical success was 96%, secondary technical success 100%. Endoleaks were observed in four (15%) patients, one requiring a second endovascular procedure. There were no conversions to open surgery. Procedure-related complications occurred in four (15%) patients. No patient developed cord injury. All cause mortality at 30 days is one (4%) and at discharge is two (7%) due to associated poly-trauma. CONCLUSION: Our results add further evidence of the safety of endovascular repair of thoracic aortic injury and compare favourably with those of other centres.

Intramural haematoma of the thoracic aorta: rupture and endoluminal exclusion.

Intramural haematoma is an increasingly recognized condition, characterized by an acute haemorrhage into the aortic wall without the creation of a pseudolumen. We present a case that was diagnosed by non-contrast CT scanning, which showed a hitherto undescribed contained rupture into the mediastinum, but no haemothorax. This complicated intramural haematoma was then successfully treated with endoluminal exclusion, which was performed during frank rupture of the thoracic aorta into the left hemithorax which occurred just before the commencement of the endoluminal exclusion.

Strut failure in the body of the zenith abdominal endoprosthesis.

OBJECTIVES: Endovascular repair of abdominal aortic aneurysm is a technology that has undergone rapid technological evolution with a number of different types of grafts developed and concern has been the structural integrity of the metallic endoskeleton. We describe our experiences of strut failure in the Zenith abdominal aneurysm endograft device. DESIGN/MATERIALS/METHODS: Eighty-four patients have undergone endovascular repair of their abdominal aortic aneurysm at Christchurch Hospital from 1996 to 2005, all with the Zenith endoprosthesis. All available plain radiographs of the endoprosthesis (AP and lateral planes) were reviewed retrospectively, by a single experience observer, to assess strut failure. RESULTS: Three cases of strut failure in second-generation grafts were identified, each in the inferior body of the graft above the iliac bifurcation. There was no clear evidence that these strut failures were associated with clinical complications. CONCLUSION: This is the first time that strut failure in the Zenith abdominal endoprosthesis has been reported. Whilst in each of our three cases this does not appear to have been of clinical significance, these findings re-iterate the necessity of life-long surveillance of this technology.

Coronary subclavian steal syndrome: non-invasive imaging and percutaneous repair.

Although coronary subclavian steal syndrome (CSSS) is relatively uncommon, it is a well documented cause of graft failure in patients having undergone coronary artery bypass grafting (CABG) using the left internal mammary artery (LIMA). Here we report a case of CSSS induced by restenosis of a left subclavian artery (SCA) origin stent, identified by increased velocities within the stent and an abnormal ipsilateral vertebral artery (VA) waveform on Duplex ultrasound imaging. This was successfully treated percutaneously by re-stenting, resulting in restoration of normal SCA waveforms and velocities, and normalization of the ipsilateral VA waveform.

Ultrasound of the extracranial vertebral artery.

Ultrasound of the extracranial vertebral artery (VA) is a valuable technique. This review outlines VA anatomy and the technical aspects of ultrasound scanning of the VA, then proceeds to demonstrate and discuss the use of ultrasound of the VA in identifying vertebral-subclavian and coronary-subclavian steal syndromes, aortic valve disease, stenosis or occlusion of the VA itself, dissection and aneurysm of the VA, and vertebrobasilar insufficiency.

Endoluminal embolization of bilateral atherosclerotic common iliac aneurysms with fibrin tissue glue (Beriplast).

The standard surgical approach to nonleaking iliac aneurysms found at repair of a leaking abdominal aortic aneurysm is to minimize the operative risk by repairing the abdominal aorta only. This means that the bypassed iliac aneurysms may have to be repaired later. As this population of patients are usually elderly with coexisting medical problems, interventional radiology is being used to embolize these aneurysms, thus avoiding the morbidity and mortality associated with further general anesthesia and surgery. Various materials and stents have been reported to be effective in the treatment of iliac aneurysms. We report the successful use of endoluminal fibrin tissue glue (Beriplast) to treat two large iliac aneurysms in a patient who had had a previous abdominal aortic aneurysm repair. We discuss the technique involved and the reasons why we used tissue glue in this patient.

Using CO2-enhanced arteriography to investigate acute gastrointestinal hemorrhage.

OBJECTIVE: The objective of the study was to compare the efficacy of CO2-enhanced arteriography with that of arteriography enhanced with standard iodinated contrast material in the detection of gastrointestinal hemorrhage. CONCLUSION: For acute gastrointestinal hemorrhage, we did not find an advantage to using CO2 to show active bleeding. In fact, CO2 was inferior to iodinated contrast material in revealing nonbleeding vascular anomalies.

Sequential retroperitoneal venous hemorrhage and embolism of an angio-seal puncture closure device complicating iliac artery angioplasty.

PURPOSE: To present a case of iatrogenic puncture closure device embolization complicating surgery for retroperitoneal hemorrhage (RPH) secondary to angioplasty-induced common iliac vein trauma. METHODS AND RESULTS: A 78-year-old woman with rest pain underwent successful kissing balloon dilation of her aortoiliac bifurcation for a calcified ostial stenosis of the left common iliac artery. Hemostatic puncture closure devices (Angio-Seal) were used to secure both femoral punctures. A right-sided retroperitoneal hematoma developed, and during surgical exploration of the right groin, the Angio-Seal device was removed. The only bleeding site found was the external iliac artery puncture and it was repaired. She again became hypovolemic 18 hours later and was returned to surgery, where bilateral groin explorations and laparotomy by the vascular surgical team found a tear in the left common iliac vein. After repair, the patient was stable for 48 hours when the left leg became critically ischemic. Angiography detected a new high-grade stenosis in the left profunda femoris artery; embolectomy retrieved a footplate from the left puncture closure device. The patient died 11 days later from multiorgan failure. CONCLUSIONS: RPH should be considered early as an occult cause of hypovolemic shock developing soon after even technically straightforward iliac angioplasty. Interventionists should be aware that using the Angio-Seal device risks acute limb ischemia if footplate embolization occurs.

Peripheral thrombolysis for acute-onset claudication. Thrombolysis Study Group.

BACKGROUND: The aim of this study was to determine the outcome of patients who presented with sudden onset of incapacitating claudication of less than 2 weeks' duration and who were treated with peripheral arterial thrombolysis. METHODS: The database of the Thrombolysis Study Group was searched retrospectively for patients who received thrombolysis for acute-onset claudication. Some 108 patients (65 men, median age 69 (range 29-94) years) were treated with intra-arterial tissue plasminogen activator at 14 hospitals. The median duration of symptoms was 72 h (range from 2 h to 2 weeks). There were 52 graft and 56 native vessel arterial occlusions. RESULTS: The immediate outcome of thrombolysis for native vessel arterial occlusion was thrombus clearance in 50 patients (89 per cent) and failed lysis in six (11 per cent). Thirty-six patients (64 per cent) had a secondary radiological or surgical procedure carried out after lysis. After 30 days four patients (7 per cent) had a major amputation, eight (14 per cent) had died, 38 (68 per cent) were symptom free and seven (12 per cent) continued to have claudication. Three patients (5 per cent) suffered a major haemorrhage. The immediate outcome of thrombolysis for graft occlusion was thrombus clearance in 48 patients (92 per cent) and failed lysis in four (8 per cent); 27 patients (52 per cent) had a secondary procedure. After 30 days four patients (8 per cent) had a major amputation, seven (13 per cent) had died, 32 (62 per cent) were symptom free and nine (17 per cent) had persistent claudication. Three patients (6 per cent) suffered a major haemorrhage. CONCLUSION: Patients who presented with acute onset of incapacitating claudication had an outcome similar to that after thrombolysis for critical ischaemia. It is recommended that patients who present in this way should be observed and treated with thrombolysis only if they progress to critical ischaemia. Presented to the Association of Surgeons of Great Britain and Ireland, Edinburgh, UK, May 1998, and published in abstract form as Br J Surg 1998; 85(Suppl 1): 24

The association between laser Doppler reactive hyperaemia curves and the distribution of peripheral arterial disease.

OBJECTIVES: To determine whether postocclusive laser Doppler fluxmetry (LDF) curves can be related to the arteriographic distribution of disease. DESIGN: Prospective study. MATERIALS: Sixty-nine patients with symptomatic peripheral ischaemia and 15 healthy subjects. METHODS: Laser Doppler fluxmetry (LDF) was monitored on the dorsum of the symptomatic foot following 2 min of arterial occlusion at the ankle. During reperfusion three patterns of LDF were identified (types I-III). All patients subsequently underwent arteriography which was reported independent of LDF results. The distribution of disease, particularly patency of below-knee vessels, was related to the type of LDF curve observed during reactive hyperaemia. RESULTS: Type I curves were observed in all healthy subjects and 75% of patients with a single arterial lesion. Type II curves were found in 78% of patients with multiple lesions above the knee. The presence of either a type I or II curve was associated with a continuous vessel from knee to ankle (positive predictive value 83%, p < 0.01), whilst type III curve was associated with discontinuous infrapopliteal run-off (positive predictive value 86%, p < 0.01). CONCLUSIONS: This pilot study suggests that post-occlusive LDF curves may identify the distribution of arterial disease and may be useful in the non-invasive management of peripheral ischaemia.

The endovascular management of blue finger syndrome.

OBJECTIVES: To review our experience of the endovascular management of upper limb embolisation secondary to an ipsilateral proximal arterial lesion. DESIGN: A retrospective study. MATERIALS AND METHODS: Over 3 years, 17 patients presented with blue fingers secondary to an ipsilateral proximal vascular lesion. These have been managed using transluminal angioplasty (14) and arterial stenting (five), combined with embolectomy (two) and anticoagulation (three)/anti-platelet therapy (14). RESULTS: All the patients were treated successfully. There have been no further symptomatic embolic episodes originating from any of the treated lesions, and no surgical amputations. Complications were associated with the use of brachial arteriotomy for vascular access. CONCLUSIONS: Endovascular techniques are safe and effective in the management of upper limb embolic phenomena associated with an ipsilateral proximal focal vascular lesion.

The use of the angio-seal haemostatic puncture closure device in high risk patients.

The use of the Angio-Seal haemostatic puncture closure device in 45 patients considered to be at increased risk of puncture site complications is described. Successful device deployment occurred in 44 of 50 arteries (88%). Two major complications were associated with, but not necessarily caused by, the Angio-Seal device. Four minor complications were observed. In a subset of 23 patients well enough to mobilize early after their procedure, 17 did so at an average of 2.6 h as opposed to the routine 12-18 h for patients after a procedure involving a 6-8F sheath. Once the initial learning curve has been overcome, the Angio-Seal device is a simple and successful method of achieving arterial haemostasis following catheterization and is associated with a low risk of complications. At present we would recommend its use for high risk patients only, as manual compression is effective in the majority of routine cases.

Carbon dioxide angiography of the lower limbs: initial experience with an automated carbon dioxide injector.

Carbon dioxide (CO2) has been used as an arterial contrast agent since 1971. The development of digital subtraction angiography and an automated CO2 injector has increased the practicability and safety of using CO2 routinely. Sixty-three patients had lower limb and/or renal arteriograms performed over a 6-month period using CO2 in comparison with iodinated contrast medium. The majority (mean 74%, range 53-86%) of non-selective studies were diagnostic to the level of the popliteal artery, and 84% of selective lower limb studies were diagnostic. No serious complications occurred. The contrast and spatial resolution of CO2 digital subtraction arteriography (CO2DSA) was not consistently as good as iodinated contrast medium in peripheral lower limb or renal studies. However, due to the absence of allergic reactions and lack of nephrotoxicity, CO2 is a diagnostic alternative to iodinated contrast medium in selected patients.

A review of alternative approaches in the management of iatrogenic femoral pseudoaneurysms.

The management of iatrogenic pseudoaneurysms (IPAs) demands close co-operation between radiologist, vascular surgeon and plastic surgeon. Ideally, each patient should be reviewed employing a team approach. Many IPAs require only observation; those with a volume greater than 6 cm3 will require treatment as spontaneous thrombosis is uncommon. Radiological treatment options include ultrasound guided compression repair (UGCR), embolisation, and covered stenting. Occasionally, these are unsuccessful or contra-indicated, and the vascular surgical approach is discussed in detail. Finally, the role of the plastic surgeon in dealing with skin ischaemia is detailed.

Update on endovascular management of arterial occlusive disease.

Although balloon angioplasty is the most widely used technique for treating peripheral vascular disease, developments in endovascular therapies have extended methods of percutaneous vascular intervention. Lasers have been used to recanalize occluded arteries. Mechanical devices can remove obstructions and metallic stents can be placed to keep a vessel open with good long-term patency.