Influence of Abdominal Aortic Aneurysm Size on the Feasibility of Endovascular Repair

Purpose:

To assess the effect of abdominal aortic aneurysm (AAA) size on overall aneurysm morphology with special attention to possible relationships among various anatomic variables that determine the feasibility of endovascular repair.

Methods:

One hundred sixty-eight patients were assessed with spiral computed tomographic angiography to measure the length and diameter of the AAA, the proximal neck, and the common iliac arteries. Anatomic variables were correlated with aneurysm size using Spearman's rank order correlation coefficients (rs); comparisons among small, intermediate, and large aneurysms were made using the Chi-square test.

Results:

Correlations between aneurysm size and the anatomic variables above were weak. The strongest association was between aneurysm size and aortic length (rs = 0.41, p < 0.001). Subgroup analysis showed no difference in proximal neck length, neck diameter, or overall suitability for endovascular repair between aneurysms greater or smaller than 5.5-cm diameter. However, significantly more short (< 1.5 cm), wide (> 3 cm), and, hence, unsuitable proximal necks were found in patients with aneurysms > 7 cm in diameter (χ2 = 7.8, p < 0.01).

Conclusions:

Shortening and widening of the proximal neck seems to increase with aneurysm size but only after the aneurysm expands beyond 7 cm in diameter. Aneurysms with diameters in the 4.5- to 5.5-cm range are no more suitable for endovascular repair than those between 5.5 and 7 cm. The lack of any significant correlation between anatomic variables emphasizes the need for accurate preoperative assessment of the anatomy of each individual patient before endovascular repair.

Spiral CT Angiography versus Aortography in the Assessment of Aortoiliac Length in Patients Undergoing Endovascular Abdominal Aortic Aneurysm Repair

Purpose:

To compare measurements of aortoiliac length obtained with spiral computed tomographic angiography (CTA) and aortography in patients undergoing endovascular aneurysm repair.

Methods:

The distances from the lower-most renal artery to the aortic bifurcation and from the aortic bifurcation to the common iliac artery (CIA) bifurcation were measured using both CTA and aortography in 108 patients with abdominal aortic aneurysms.

Results:

The level of agreement between CTA and aortography was high, with 69% of aortic and 76% of iliac measurements within 1 cm and > 90% within 2 cm of each other. Mean differences were −0.35 ± 1.20 cm and 0.25 ± 1.10 cm, respectively, for aortic and iliac lengths. Aortography overestimated renal artery to aortic bifurcation length in comparison to CTA (p = 0.003), particularly in patients with large aneurysms (> 6.5 cm) and lumen diameters > 4.5 cm (p < 0.0001). Measurements of CIA length were shorter by aortography than CTA (p = 0.02).

Conclusions:

There is a high level of agreement between CTA and aortography in the measurement of aortoiliac length, but aortography overestimates renal artery to aortic bifurcation length in patients with large-diameter aneurysms and wide aneurysm lumens. CTA is sufficiently accurate in the majority of cases to be used as the sole basis for the construction of endovascular grafts.

Investigation of the relationship between transcranial impedance and intracranial pressure

Studies on piglets have shown that cranial bioimpedance (Z) measurements correlate well with invasively measured intracranial pressure (ICP). We have tested the feasibility of collecting transcranial impedance from a clinical device for measuring whole-body water content (ImpediMed SFB7). In the clinical study, 50 normal healthy volunteers had transcranial impedance measured using nine different head montages (forehead to mastoid (left/right), temporal to mastoid (left/right), forehead to temporal (left/right), forehead to occipital (left/right) and temporal to temporal). Impedance was measured 20 times over a frequency range per montage and ANOVA used to test for effects of electrode position upon recorded value. For the experimental study, five sedated and ventilated Marino sheep were instrumented for intraventricular ICP and transcranial impedance measurement. Measures of ICP were recorded while ICP was increased from baseline to greater than 50 mmHg in five steps using an intraventricular infusion of mock CSF. There is a significant effect of electrode position and gender upon transcranial impedance (p < 0.001). The temporal-mastoid electrode position had significantly lower impedance values in keeping with its shorter path length. ICP correlated with craniospinal compliance measurements and Impedance vs Freq by ICP step shows a clear ICP dependence (p = 0.007) across the sheep.

Reducing the oxygen concentration of gases delivered from anaesthetic machines unadapted for medical air

High fractional concentrations of inspired oxygen (FiO(2)) delivered over prolonged periods produce characteristic histological changes in the lungs and airway of exposed animals. Modern medical anaesthetic machines are adapted to deliver medical air (FiO(2)=0.21) for the purpose of reducing FiO(2); anaesthetic machines designed for the veterinary market have not been so adapted. Two inexpensive modifications that allow medical air to be added to the gas flow from veterinary anaesthetic machines are described. The advantages and disadvantages of each modification are discussed.

Radiological classification of optic pathway gliomas: experience of a modified functional classification system

Optic pathway gliomas (OPGs) in childhood are associated with neurofibromatosis type 1 (NF1) and since 1958 have been classified anatomically using the Dodge classification (DC). MR scanning permits a more detailed anatomical description than can be classified by this historical system. A modified Dodge classification (MDC) has been applied to MRI scans from a cohort of 72 patients (36.1% NF1-positive) from 4 centres participating in an international clinical trial. The MDC was feasible, applicable and more detailed than the original DC. NF1-positive cases more commonly involved both optic nerves (p = 0.021) and other multiple locations (p = 0.001). NF1-negative tumours more commonly involved the central chiasm (p = 0.005) and hypothalamus (p = 0.003). Fewer hypothalamus-positive tumours were associated with optic nerve involvement (p = 0.009), whereas more were associated with central chiasm involvement (p<0.001). From diagnosis to follow-up, there was concordance between DC and MDC in 51/72 cases (70.8%). The MDC is therefore proposed for use in clinical trials of new treatments for OPGs.

An oral carcinogenicity and toxicity study of senna (Tinnevelly senna fruits) in the rat

Senna (Tinnevelly senna fruits), a known laxative derived from plants, was administered by gavage to Sprague-Dawley (Crl:CD (SD) BR) rats once daily at dose levels of 0, 25, 100 and 300 mg/kg/day for up to 104 consecutive weeks. Based upon clinical signs related to the laxation effect of senna, the highest dose (300 mg/kg/day) was considered to be a maximum tolerated dose. Sixty animals per sex were assigned to the control and dose groups. Assessments included clinical chemistry, hematology, full histology (control and high-dose groups; in addition, low and mid dose: intestinal tract, adrenals, liver, kidneys, brain and gross lesions) and toxicokinetics. The primary treatment-related clinical observation was mucoid feces seen at 300 mg/kg/day. When compared to controls, animals administered 300 mg/kg/day had slightly reduced body weights, increased water consumption and notable changes in electrolytes in serum (increases in potassium and chloride) and urine (decreases in sodium, potassium and chloride). The changes in electrolytes are most likely physiologic adaptations to the laxative effect of senna. At necropsy, dark discoloration of the kidneys was observed in animals in all treated groups. Histological changes were seen in the kidneys of animals from all treated groups and included slight to moderate tubular basophilia and tubular pigment deposits. In addition, for all treated groups, minimal to slight hyperplasia was evident in the colon and cecum. These histological changes, together with the changes seen in the evaluation of clinical chemistry and urine parameters, have been shown to be reversible in a previous 13-week rat study of senna. No treatment-related neoplastic changes were observed in any of the examined organs. Based upon these data, it is concluded that senna is not carcinogenic even after daily administration for 2 years at dosages of up to 300 mg/kg/day in Sprague-Dawley rats.

A 13-week oral toxicity study of senna in the rat with an 8-week recovery period

Senna was administered by gavage to Sprague Dawley rats once daily at dose levels of 0, 100, 300, 750 or 1500 mg/kg for up to 13 consecutive weeks followed by an 8-week recovery period for selected animals. Dose- and treatment-related clinical signs included abnormal feces, which were seen to varying degrees from animals at 300 mg/kg per day and more. Animals receiving 750 or 1500 mg/kg per day had significantly reduced body weight gain (males only) and, related to the laxative properties of senna, increased water consumption and notable changes in electrolytes in both serum and urine. At both the terminal and recovery phase necropsy, an increase in absolute and relative kidney weights was seen for male and female animals receiving 750 and/or 1500 mg/kg per day. A dark discoloration of the kidneys was observed at necropsy along with histopathological changes in the kidneys (slight to moderate tubular basophilia and pigment deposits) at 300 mg/kg and above. However, there were no indications in laboratory parameters of any renal dysfunction. In addition, for all treated groups, minimal to slight hyperplasia was recorded in the forestomach and large intestine. Following 8 weeks of recovery, with the exception of the brown pigment in the kidneys, there were no histopathological abnormalities. Thus, the biochemical and morphological changes seen following 13 weeks of treatment of senna significantly reversed following 8 weeks of recovery.

Handwashing

Hands are easily contaminated by transient bacteria and nurses must be aware of when and how to wash them and whether social handwashing or hygienic hand disinfection is required. Regular updates on good practice are recommended.

Feasibility of using dynamic contrast-enhanced magnetic resonance angiography as the sole imaging modality prior to endovascular repair of abdominal aortic aneurysms

OBJECTIVES

to establish the feasibility of using magnetic resonance imaging (MRI) with dynamic contrast-enhanced (DCE) MRA as the sole imaging modality in the assessment of patients prior to endovascular repair of abdominal aortic aneurysms (AAAs).

DESIGN

DCE MRA with MRI and helical computed tomography (CT) examinations were performed in patients being assessed for suitability for an endovascular approach to repair of their AAA. Management outcomes determined by the two techniques were compared.

MATERIALS

sixteen patients with AAA.

METHODS

all subjects underwent DCE MRA/MRI and helical CTA. Criteria for suitability for endovascular repair were established. The management outcomes determined by the MRI findings were compared with those obtained by CTA.

RESULTS

high-quality MRA/MRI and CT images were obtained in 16 patients. Six patients were considered suitable for an endovascular approach, one was considered borderline and nine were judged unsuitable. In all cases, the overall management determined by the two methods concurred.

CONCLUSIONS

comparison of the two imaging modalities resulted in agreement as to suitability for an endovascular approach. We therefore conclude that in our group the use of MRI and DCE-MRA proved effective as a sole imaging modality for the assessment of these patients.

Severe retinopathy of prematurity and its association with different rates of survival in infants of less than 1251 g birth weight

BACKGROUND

There is controversy over whether improved survival of preterm infants has resulted in a higher incidence of severe (grade 3 or greater) retinopathy of prematurity (ROP).

AIM

To compare survival rates and rates of > or = stage 3 ROP-that is, with a high risk of sequelae-in preterm infants in five English cities where, anecdotally, the incidence of ROP is reported to show considerable variation.

METHODS

All infants of birth weight < 1500 g and or gestational age < 32 weeks, born in 1994 in one of the cities or transferred in within 48 hours, were studied. The populations were adjusted for case mix variation using CRIB (clinical risk index for babies, a disease severity scoring system). The incidence of severe ROP, the actual death rate, and that adjusted for disease severity were determined.

RESULTS

The rate of severe ROP per 1000 births was higher in city 1 than in all the other cities. This increase in comparison with city 2 and city 4 was significant (city 1, 167 (95% confidence interval (CI) 96 to 260); city 2, 24 (6 to 59); city 4, 16 (1 to 84)). A significant difference was not seen between city 1 and cities 3 (23 (1 to 120)) and 5 (74 (21 to 79)). The relative risk of developing severe ROP in city 1 compared with all the other cities was 5.5 (2.5 to 11.9). The actual death rate per 1000 births in city 1 was significantly lower than that predicted by modelling death against CRIB score (city 1: actual 270; predicted 385 (95% CI 339 to 431)). In contrast, the other cities had actual death rates as predicted, or worse than predicted, by CRIB.

INTERPRETATION

A significantly higher incidence of severe ROP was identified in one of the five cities studied. Variation in survival rates among high risk infants may explain this observation.

Mortality rates following endovascular repair of abdominal aortic aneurysms

PURPOSE

To present the perioperative and late mortality following endovascular repair (EVR) of abdominal aortic aneurysms (AAAs).

METHODS

Data were collected prospectively on 221 patients undergoing AAA EVR over a 4-year period (median 5-month follow-up). Patients were classified preoperatively as high risk with at least 1 of these features: serum creatinine > 150 micromol/L, ischemic heart disease or poor left ventricular function, respiratory function < 50% of predicted normal, ruptured or symptomatic AAA, contraindication to or failed open repair, and age > 80 years.

RESULTS

One hundred forty (63.3%) patients were classified as high risk, the most common criterion being cardiac disease (n = 96, 68.6%). There were 25 (11.3%) deaths in the 30-day perioperative period, 22 (15.7%) in the high-risk group compared to 3 (3.7%) in the acceptable-risk group (p = 0.02). The most common causes of perioperative death were multisystem organ failure and myocardial infarction. A further 21 (9.5%) late deaths occurred, 16 (11.4%) in the high-risk group and 5 (6.2%) in the acceptable-risk group (p > 0.1).

CONCLUSIONS

The mortality of patients at acceptable risk undergoing EVR compares with the best published series for conventional open AAA repair. The perioperative and late mortality in the high-risk patients are substantially higher.

Vascular surgical society of great britain and ireland: changes in proximal aortic neck dimensions following endovascular repair of abdominal aortic aneurysm

BACKGROUND: Dilatation of the proximal neck following conventional open repair of abdominal aortic aneurysm (AAA) has been reported. Such continued dilatation following endovascular repair (EVR) could potentially be a disaster resulting in graft slippage, endoleak and aneurysm rupture. The aim of this study was to detect any change in proximal neck diameter following EVR of AAAs. METHODS: One hundred patients had undergone EVR of an AAA over a 4-year period in whom contrast-enhanced spiral computed tomography was performed both before and after EVR (1 week, 3, 6 and 12 months and annually thereafter). Change in aortic proximal neck diameter, change in maximum aortic diameter, presence of endoleaks, and change in length from the lowest renal artery to the aortic bifurcation was sought. RESULTS: The median anteroposterior and transverse diameter decreased from 64 mm before operation to 56 and 54 mm respectively after operation. This trend in reduction in maximum diameter was not seen in patients with endoleaks. There was no significant change in proximal neck diameter when measured at 5-mm intervals following EVR. There was also no significant change in the aortic length following EVR. CONCLUSION: There was no evidence of proximal neck dilatation or aneurysm length reduction following EVR of AAAs.

A prospective study to assess changes in proximal aortic neck dimensions after endovascular repair of abdominal aortic aneurysms

OBJECTIVE

The purpose of this study was to detect any change in the proximal neck diameter after endovascular repair of abdominal aortic aneurysm.

METHODS

The study was performed in a teaching hospital with an endovascular program on 112 patients who had undergone endovascular repair of abdominal aortic aneurysm. The interventions were pre-endovascular and postendovascular repair of abdominal aortic aneurysms with contrast-enhanced, spiral computerized tomography, and the main outcome measures were change in aortic proximal neck diameter, change in maximum aortic diameter, presence of endoleaks, and change in length from lowest renal artery to aortic bifurcation.

RESULTS

The median anterior-posterior and transverse diameter decreased from 63.5 mm before surgery to 50.4 and 54.5 mm, respectively, after surgery in a period of 4 years. This trend in reduction in maximum diameter was not seen in the patients with endoleaks. There was no significant change in the proximal neck diameters when measured at 5-mm intervals after endovascular repair. There was also no significant change in the aortic length after endovascular repair.

CONCLUSION

We have not demonstrated any evidence for proximal neck dilatation after endovascular repair of abdominal aortic aneurysm.

The standard of laparoscopic intraoperative cholangiography: a quality control study

BACKGROUND AND STUDY AIMS

One reason why many surgeons do not attempt laparoscopic cholangiography is that it is considered to be technically difficult and to produce poor-quality images.

PATIENTS AND METHODS

A retrospective comparison was made of twenty randomly selected intraoperative cholangiograms taken during laparoscopic cholecystectomy for each year from 1991 to 1994 (n = 80) by assigning a score (0-4) on the basis of anatomical parameters and radiographic quality. Twenty randomly selected intraoperative cholangiograms taken during open cholecystectomy (OC) were used as controls.

RESULTS

The average score for the laparoscopic cholangiograms (LCs) was significantly lower than the average for OC cholangiograms (2.3 vs. 3.4, P< 0.001). In addition, a learning curve was demonstrated, which showed significant improvement in the quality of LCs over the years. Analysis showed that in LCs, only 34 % succeeded in demonstrating the entire biliary tree and only 49% managed to show the extrahepatic duct system. Choledocholithiasis could only be ruled out in 53 % of LC films, compared with 80 % of controls.

CONCLUSIONS

Despite an improvement in the quality of laparoscopic cholangiography, it remains inferior to cholangiography during open cholecystectomy. Recommendations are made regarding ways in which improvements could be achieved.

Thrombus distribution and changes in aneurysm size following endovascular aortic aneurysm repair

OBJECTIVES

To determine (a) changes in aneurysm size following endovascular repair, (b) the significance of collateral lumbar artery blood flow and (c) the relationship between thrombus distribution within the aneurysm sac and the development of a "lumbar endoleak".

MATERIALS AND METHODS

72 patients treated with endovascular stent-grafts were followed up with spiral computed tomography for a median of 11 (range 3-27) months. The cross-sectional area of the aneurysm was measured at the point of maximum diameter pre- and post-operatively. The distribution and quantity of thrombus was recorded pre-operatively and this was related to changes in aneurysm size and the development of lumbar endoleaks post-operatively.

RESULTS

An increase in aneurysm size occurred in 22 patients, of whom 10 had endoleaks. Fifteen aneurysms did not change in size, including four with endoleak, and 35 aneurysms decreased in size with no endoleaks. There was a significant difference between the endoleak and no endoleak groups (Chi-squared test = 17.1 with 2 degrees of freedom (d.f.), p < 0.001). Nine endoleaks were from patent lumbar arteries. No patients with thick circumferential or posteriorly placed thrombus developed an endoleak arising from lumbar vessels (0/23 cases) compared to those with minimal or anteriorly placed thrombus (9/49 cases) (Chi-squared test with Yate's correction = 3.17 with 1 d.f., p < 0.1).

CONCLUSIONS

Aneurysms do not decrease in size in the presence of a lumbar endoleak, and some expand significantly. A number of aneurysms increase in size despite no evidence of an endoleak on computed tomography (CT). Patterns of thrombus distribution may be able to predict patients at risk from persistent endoleak via lumbar vessels.

A study on the patency of the inferior mesenteric and lumbar arteries in the incidence of endoleak following endovascular repair of infra-renal aortic aneurysms

OBJECTIVE

An endoleak is defined as the presence of contrast medium within the aneurysm sac on post-operative contrast-enhanced computed tomography scans (CT) in patients following endovascular repair (EVR) of abdominal aortic aneurysms (AAA). The aim of this study was to correlate the incidence of endoleaks with the presence of patent lumbar (LA) and inferior mesenteric arteries (IMA) as seen on pre-operative angiography.

DESIGN, MATERIALS AND METHODS

Forty-seven patients were assessed pre-operatively by both CT and angiography by a blinded radiologist prior to EVR of AAA. The number and size of patent vessels was recorded and correlated with the incidence of LA or IMA endoleaks on follow-up CT. Patent lumbar vessels were scored: 1 = small, 2 = medium, 3 = large.

RESULTS

Five patients were noted to have patent IMA on pre-operative angiography but none developed an endoleak. In this series, five patients had an endoleak due to a patent LA. The median score for patients with no endoleak was 1 (0-9) and for those with a lumbar endoleak 2 (0-5) (P = 0.26, Mann-Whitney U-test). The number of patent lumbar arteries was not predictive of a subsequent endoleak. Two out of nine (22 %) patients with large patent LA subsequently developed an endoleak. If a policy of pre-operative embolization on the basis of large patent LA had been adopted, seven patients would have had an unnecessary invasive procedure.

CONCLUSION

Pre-operative angiography to look for patent LA and IMAs is not required in patients undergoing EVR or AAA.

Spiral CT angiography versus aortography in the assessment of aortoiliac length in patients undergoing endovascular abdominal aortic aneurysm repair

PURPOSE

To compare measurements of aortoiliac length obtained with spiral computed tomographic angiography (CTA) and aortography in patients undergoing endovascular aneurysm repair.

METHODS

The distances from the lower-most renal artery to the aortic bifurcation and from the aortic bifurcation to the common iliac artery (CIA) bifurcation were measured using both CTA and aortography in 108 patients with abdominal aortic aneurysms.

RESULTS

The level of agreement between CTA and aortography was high, with 69% of aortic and 76% of iliac measurements within 1 cm and > 90% within 2 cm of each other. Mean differences were -0.35 +/- 1.20 cm and 0.25 +/- 1.10 cm, respectively, for aortic and iliac lengths. Aortography overestimated renal artery to aortic bifurcation length in comparison to CTA (p = 0.003), particularly in patients with large aneurysms (> 6.5 cm) and lumen diameters > 4.5 cm (p < 0.0001). Measurements of CIA length were shorter by aortography than CTA (p = 0.02).

CONCLUSIONS

There is a high level of agreement between CTA and aortography in the measurement of aortoiliac length, but aortography overestimates renal artery to aortic bifurcation length in patients with large-diameter aneurysms and wide aneurysm lumens. CTA is sufficiently accurate in the majority of cases to be used as the sole basis for the construction of endovascular grafts.

Common iliac artery aneurysms in patients with abdominal aortic aneurysms

OBJECTIVES

To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter.

METHODS

Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA.

RESULTS

The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak.

CONCLUSIONS

The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.

Common iliac artery aneurysms in patients with abdominal aortic aneurysms

OBJECTIVES

To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter.

METHODS

Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA.

RESULTS

The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak.

CONCLUSIONS

The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.

Influence of abdominal aortic aneurysm size on the feasibility of endovascular repair

PURPOSE

To assess the effect of abdominal aortic aneurysm (AAA) size on overall aneurysm morphology with special attention to possible relationships among various anatomic variables that determine the feasibility of endovascular repair.

METHODS

One hundred sixty-eight patients were assessed with spiral computed tomographic angiography to measure the length and diameter of the AAA, the proximal neck, and the common iliac arteries. Anatomic variables were correlated with aneurysm size using Spearman's rank order correlation coefficients (rS); comparisons among small, intermediate, and large aneurysms were made using the Chi-square test.

RESULTS

Correlations between aneurysm size and the anatomic variables above were weak. The strongest association was between aneurysm size and aortic length (rS = 0.41, p < 0.001). Subgroup analysis showed no difference in proximal neck length, neck diameter, or overall suitability for endovascular repair between aneurysms greater or smaller than 5.5-cm diameter. However, significantly more short (< 1.5 cm), wide (> 3 cm), and hence, unsuitable proximal necks were found in patients with aneurysms > 7 cm in diameter (chi 2 = 7.8, p < 0.01).

CONCLUSIONS

Shortening and widening of the proximal neck seems to increase with aneurysm size but only after the aneurysm expands beyond 7 cm in diameter. Aneurysms with diameters in the 4.5- to 5.5-cm range are no more suitable for endovascular repair than those between 5.5 and 7 cm. The lack of any significant correlation between anatomic variables emphasizes the need for accurate preoperative assessment of the anatomy of each individual patient before endovascular repair.

False aneurysm of a lumbar artery following vertebral biopsy

Vertebral body biopsy is regarded as a simple and relatively safe technique, with a low complication rate. We report the case of an 80-year-old man who developed a false aneurysm of a lumbar artery following biopsy of the fourth lumbar vertebra.

The anatomy of abdominal aortic aneurysms: implications for sizing of endovascular grafts

OBJECTIVE

To determine the full range of aorto-iliac anatomy of patients with abdominal aortic aneurysms (AAAs) and thence the range of endovascular graft sizes required to deal with the majority of AAAs.

DESIGN

Analysis of preoperative spiral CT measurements.

MATERIALS

One hundred and sixty-eight patients with AAAs.

METHODS

Multiplanar reconstruction measurements were taken of proximal aortic neck diameter and length, lowermost renal artery to the aortic bifurcation distance and length and diameter of common iliac arteries. Based on these measurements a range of graft sizes that would fit the majority of AAAs was determined.

RESULTS

Ranges of anatomical variables were as follows: proximal aortic neck diameter 18-30 mm, renal artery to aortic bifurcation distance 93-210 mm, common iliac artery length 13-108 mm, common iliac artery diameter 6-67 mm. Over 750 graft sizes would be required to cover all anatomical combinations using a one-piece aorto-uni-iliac graft.

CONCLUSION

A wide variety of aorto-iliac anatomy exists in patients with AAAs. The large number of graft sizes required to deal with the majority of AAAs makes the production of one-piece endovascular grafts commercially impractical. A proposed two-piece modular graft would allow the majority of AAAs to be treated using only 16 graft sizes.

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.

Early results of endovascular aortic aneurysm surgery with aortouniiliac graft, contralateral iliac occlusion, and femorofemoral bypass

PURPOSE

The aim of this study was to evaluate the feasibility of endovascular aortic aneurysm repair with use of an aortouniiliac graft secured with self-expanding (Gianturco) stents.

METHODS

Thirty patients with a median age of 72 years (age range, 52 to 86 years) and aneurysm diameter of 6.0 cm (range, 4.0 to 9.0 cm) were treated with an aortouniiliac endovascular graft. Of these 30 procedures, 28 were carried out electively and two as emergencies for leaking aneurysm. Of the 30 patients, 21 (70%) were considered to be at high risk for open surgery. A modified Gianturco stent, Dacron graft, and Wallstent were used for these procedures.

RESULTS

Endovascular repair was successfully carried out in 25 of 30 (83.3%) patients. All these patients were mobile and had resumed a normal diet within 48 hours of the procedure. The overall 30-day mortality rate was two in 30 (6.6%), but it was one in 28 (3.5%) for the elective cases; all deaths occurred in the group at high risk for surgery. Other complications encountered within 30 days of procedure included myocardial infarction in one patient, pneumonia in two patients, homonymous quadrantanopia in one patient, and colonic ischemia in one patient, giving an overall morbidity rate of four in 30 (13.3%). At a median follow-up of 4 months (range, 1 to 13 months), 27 of 30 (90%) patients remain alive and well.

CONCLUSION

Endovascular aortouniiliac repair of abdominal aortic aneurysm with Gianturco stent is feasible in both elective and emergency situations. It appears to be minimally traumatic, and the majority of patients deemed to be at high risk for open surgery can safely undergo endovascular repair. However, data on more patients with longer follow-up is required to determine its role in the management of abdominal aortic aneurysm.

Results of 100 cases of pulse-spray thrombolysis for acute and subacute leg ischaemia

BACKGROUND

Pulse-spray thrombolysis is a rapid technique for the treatment of limb ischaemia of recent onset. Early results have been published but the longer term results are not known.

METHODS

This study consisted of a series of 100 legs with acute and subacute ischaemia treated using this method with a follow-up interval of up to 3 years. Eighty-three limbs were classified as Fontaine grade III or IV and 42 had a sensory or motor deficit. Sixty-seven limbs were treated with pulse spray alone and 33 had an additional low-dose infusion. In 71 cases an additional catheter-directed intervention was required.

RESULTS

Median duration of lysis was 135 (range 35-1540) min and median dose of recombinant tissue plasminogen activator used was 18 (range 4-61) mg. Complete radiological patency was achieved in 79 limbs and the ankle:brachial pressure index improved from a median of 0 (range 0-0.8) to 0.8 (range 0-1.5) (P < 0.0001). At 30 days ten patients had died, eight needed amputation and a further 11 had rethrombosed. Cumulative limb salvage rate at 30 months was 79 per cent (standard error 8) and the estimated cumulative patency rate for successful cases was 72 per cent (standard error 10). The incidence of major bleeding was 7 per cent and of minor bleeding 24 per cent. There were no haemorrhagic strokes but three thrombotic strokes occurred within 30 days of thrombolysis.

CONCLUSION

Pulse-spray thrombolysis achieves rapid and safe revascularization of acute and subacute leg ischaemia.

Value of a weekly surgical x-ray meeting

Surgical x-ray meetings attended by surgeons and radiologists are used for the clarification of x-ray reports and education of those present. Although the value of these meetings is generally accepted in terms of education, it is not known in what way they contribute to patient management. An audit of the authors' weekly surgical x-ray meeting to determine whether such reports and management decisions are modified following review and whether this is of benefit to patients is described.

Carbon dioxide: an alternative to iodinated contrast media

OBJECTIVES

To study the use of carbon dioxide as a contrast medium for arteriography.

METHODS

Carbon dioxide was used as a contrast medium for intra-arterial digital subtraction lower limb angiography in 12 examinations on 11 patients.

RESULTS

No complication was encountered and no significant changes occurred in the arterial pH, PaCO2 and PaO2. The quality of images as assessed by an independent observer was adequate for the majority of the vessels (77%).

CONCLUSIONS

Carbon dioxide is a safe alternative in patients at an increased risk of adverse reaction to iodinated ionic or non-ionic contrast medium and is very cheap.

Prospective randomised comparative study of pulse spray and conventional local thrombolysis

OBJECTIVES

To compare the time required to achieve lysis with the pulse spray technique and the conventional slow continuous infusion technique.

DESIGN

Prospective randomised open Study.

METHODS

Eighteen patients suitable for intra-arterial thrombolytic therapy with conventional and pulse spray technique were randomised 1:1 to receive either pulse spray thrombolysis with 0.33 mg/ml rt-PA injected as a bolus of 0.2 ml or conventional thrombolysis with 0.05 mg/ml rt-PA infused at a rate of 10 ml/h.

RESULTS

The age, duration of symptoms, length of occlusion and prethrombolysis ankle brachial pressure index were comparable in the two groups. The median duration of thrombolytic therapy in the pulse spray group was 195 min (range 90-1260) compared to 1390 min (range 300-2400) in the Conventional group. The difference between the two groups was significant, p < 0.002 (Mann-Whitney test).

CONCLUSIONS

Significantly shorter time is required to achieve local thrombolysis with pulse spray compared to the conventional infusion method.

Endoluminal transfemoral abdominal aortic aneurysm repair with aorto-uni-iliac graft and femorofemoral bypass

Endoluminal transfemoral repair of abdominal aortic aneurysm (AAA) is an important development but large aneurysms seldom have a distal neck suitable for the currently available devices for a straight aortoaortic graft1–3. A bifurcated graft system overcomes the limitation of lack of distal neck but it is unsuitable for a significant proportion of aneurysms because of a wide or aneurysmal iliac vessel1. An alternative technique of aorto-uni-iliac graft with occlusion of the contralateral common iliac with embolization and a femorofemoral crossover graft is described.

Immediate and early follow-up results of purse spray thrombolysis in patients with peripheral ischaemia

Pulse spray thrombolysis is a technique of accelerated peripheral thrombolysis which has been evaluated in 38 patients, 29 with threatened limb viability and nine with a viable but critically ischaemic limb. The median length of occlusion was 26.5 (range 3-65) cm. The lytic agent used was recombinant tissue plasminogen activator (rtPA), injected manually via a pulse spray catheter at a concentration of 0.33 mg/ml and a bolus size of 0.2 ml. The median total dose of rtPA was 18 (range 5-35)mg. Patency and flow were completely restored in 34 of 38 patients and clinical success at 30 days was maintained in 27 of 38. The median lysis time was 120 (range 35-1125) min, compared with a median duration of 1545 (range 42-5760) min in 120 consecutive patients previously treated with conventional low-dose infusion thrombolysis using rtPA. This represents a 12-fold reduction in lysis time (P < 0.001). The overall estimated cumulative limb salvage rate for the 38 patients who entered the study was 84 per cent and the cumulative patency rate for the 34 patients in whom patency was restored was 74 per cent at 18 months follow-up. Pulse spray thrombolysis rapidly restores patency with good limb salvage at 30 days; the benefit is sustained even in patients with limbs at immediate risk of irreversible ischaemic injury who are not considered suitable for conventional thrombolysis.

Eye splashes during invasive vascular procedures

In recent years there has been an increased awareness among health care workers regarding possible risk of nosocomial transmission of blood borne pathogens. The aim of this study is to document the risk of contamination of radiologists' eyes during invasive vascular procedures. Radiologists performing these examinations were asked to wear glasses throughout. After each examination the glasses were inspected for droplets. 150 procedures were performed on 123 patients (M = 80, F = 43). 10 procedures (6.7%) resulted in splashes to glasses. In four of these cases the radiologist was not aware of the "eye splash" nor was there a spray event to account for it. Radiologists were aware of 13 spray events (8.7% of all procedures). There was a significantly increased risk of spray events and eye splashes during thrombolysis (chi 2 = 14.93, p < 0.001) and of spray events during angioplasty when compared with perfemoral arteriography (chi 2 = 8.816, p < 0.01). Procedures lasting longer than 30 min were associated with a significantly increased risk of spray events (chi 2 = 5.63, p < 0.02). Significantly more eye splashes were associated with more than two catheter changes (chi 2 = 8.912, p < 0.01). It is suggested that protective eye wear should be used routinely during invasive vascular procedures.

Congenital hypertrophy of the retinal pigment epithelium and mandibular osteomata as markers in familial colorectal cancer

Congenital hypertrophy of the retinal pigment epithelium (CHRPE) and multiple mandibular osteomata are markers of familial adenomatous polyposis (FAP). We have assessed their prevalence in non-polyposis familial colorectal neoplasia. Multiple mandibular osteomata were present in 1/29 (3%) patients with familial colorectal neoplasia. CHRPE was present in 11/33 (33%) patients with familial colorectal neoplasia compared with 3/36 (8%) with sporadic disease (P = 0.01) and 4/32 (12.5%) control subjects (P = 0.04). Seven patients with familial colorectal neoplasia had multiple areas of CHRPE compared with one with sporadic disease (P = 0.02) and one control subject (P = 0.02). There was no obvious correlation between calculated familial colorectal cancer risk and the presence of multiple areas of CHRPE. A proportion of patients with familial colorectal cancer have a marker found in FAP and may therefore have a constitutional genetic defect, at least in part responsible for their cancer, making them an interesting group for genetic study. Ophthalmoscopy may contribute to risk assessment in familial colorectal cancer.

Experience with pulse-spray technique in peripheral thrombolysis

Pulse-spray thrombolysis (PST) is a new technique of accelerated peripheral arterial thrombolysis. This technique has been evaluated on 24 patients with limb ischaemia. Severe acute limb-threatening ischaemia with sensory and motor deficit was present in 11/24 (45.8%) patients. The median dose of recombinant tissue plasminogen activator (rt-PA) used was 18 mg (10-35 mg) injected in a concentration of 0.33 mg/ml and bolus size of 0.2 ml. The median length of occlusions treated was 23 cm (range 4-55 cm). Complete initial lysis was achieved in 23/24 (95.8%) and limb salvage at 30 days was achieved in 18/24 (75%) of the cases. The overall 30-days mortality was 4/24 (16.6%) and 2/4 (50%) in those who required surgical intervention. The median duration of thrombolytic treatment was 137.5 minutes (range 35-1125 minutes) which is an 11-fold and significant reduction (p < 0.001, Mann-Whitney) in lysis time compared with the results of conventional low dose infusion of rt-PA at a rate of 0.5 mg/h in 120 consecutive patients in our unit. PST rapidly restores vascular patency and may become the treatment of choice for acute limb ischaemia including those at immediate risk of irreversible ischaemic injury which would not be considered suitable for conventional thrombolysis.

The role of angiography in the investigation of acute or chronic gastrointestinal haemorrhage

We have reviewed the clinical details and radiology of all patients with non-variceal gastrointestinal haemorrhage referred for angiography during an 8 year period. Forty-six patients with a history of overt bleeding had 49 technically satisfactory angiograms of which 29 were true positives but 16 were false negatives (sensitivity 64%, accuracy 63%). The accuracy of angiography in this group was much higher (92%) in those patients referred within 24 h of admission. Nine patients who had a history of iron-deficiency anaemia due to sub-acute blood loss had 9 angiograms. Five studies in this group were correct (two true negatives and three true positives) but there were four false positive studies. Angiography is an effective means of diagnosis in patients with acute gastrointestinal haemorrhage who have a negative endoscopy but best results will only be achieved when the study is performed with minimal delay following negative endoscopy. Angiography should also be considered in patients with continuing subacute blood loss when other investigations are negative.

Peripheral arterial thrombolysis: intermediate-term results

To determine the intermediate-term results of intra-arterial thrombolysis, 127 consecutive patients receiving 129 courses of treatment were reviewed at a median follow-up of 3 years. At initial review, 30 days after treatment, thrombolysis was successful in 63 cases (49 per cent). Of these patients, 16 were lost to follow-up: 15 died without further vascular symptoms and one moved from the area. Some 35 patients were alive and asymptomatic, of whom 33 had either angiographic or clinical evidence of continued arterial patency. Symptomatic reocclusion occurred in 12 cases; a further two patients remained asymptomatic and reocclusion was detected at follow-up. Two of the 12 symptomatic patients required amputation. Estimated patency rates were 80 per cent at 1 year, 72 per cent at 2 years and 70 per cent at 3 years. The intermediate-term results in the 66 cases in which lysis was unsuccessful were worse, only 16 patients (24 per cent) surviving to follow-up with the treated limb intact. It is concluded that, if thrombolysis is successful at 30 days, the intermediate-term results are good.

Community ophthalmology pilot study

A randomly selected sample of subjects over 75 years old or housebound in three London inner city general practices were screened for eye disease by an ophthalmologist and an ophthalmic trained nurse. All subjects were examined at specialist outreach clinics run at the surgery of their general practitioner (GP), except for the housebound who were assessed by domiciliary visit. Patients presenting to their GP with an eye problem during the study were also seen at the outreach clinic at the GP's request. Over the 3-month period of the study, 126 over-75s, 62 housebound and 35 GP referrals were seen. This pilot study found high prevalence rates of treatable eye disease in the elderly and housebound subjects and these are compared with the findings of other epidemiological surveys. The needs for health care provision to this sector of the community and the feasibility of providing it through outreach clinics are also discussed.

Case report: congenital mediastinal arteriovenous fistula in an adult--diagnosis with digital subtraction angiography

A case of asymptomatic congenital mediastinal arteriovenous fistula detected in an adult patient is presented. The diagnosis was suspected clinically and confirmed with intravenous digital subtraction angiography. The clinical and radiological features are discussed and the literature reviewed.

Current uses of ophthalmic lasers

Current laser treatments are quick, relatively painless, and well tolerated. Some ophthalmic techniques can be performed only by laser while others have a lower morbidity than alternative treatments. Peripheral retinal photocoagulation and focal photocoagulation now offer greatly improved visual prognosis for diabetic patients with proliferative diabetic retinopathy or diabetic macular disease. Selected cases of macular degeneration may be treated by focal laser photocoagulation. The role of lasers in treating sub-retinal neovascular membranes is limited by the extent and location of the membrane at presentation and the high risk of recurrence after treatment. Patients with distorted vision must be referred urgently for specialist ophthalmic assessment. Flat retinal holes and tears may be sealed by laser therapy, thus preventing retinal detachment. Short pulsed neodymium-YAG photodisruptive capsulotomy effectively clears the visual axis of thickened posterior lens capsule after cataract surgery. Short pulsed neodymium-YAG photodisruptive iridotomy may be used to treat and prevent angle closure glaucoma. Laser trabeculoplasty aids the control of open angle glaucoma. Research is continuing into the role of other lasers in managing open angle glaucoma and of photoablative lasers in treating refractive errors and superficial corneal disorders.

Recombinant tissue-type plasminogen activator is superior to streptokinase for local intra-arterial thrombolysis

The results of local intra-arterial thrombolysis in 98 patients treated with streptokinase and 69 patients treated with recombinant tissue plasminogen activator (rtPA) have been compared. The two groups of patients were well matched and their treatment protocols were identical except with regard to the thrombolytic agent used. Strict criteria for defining successful thrombolysis were used. Successful lysis was achieved in 40 of 98 patients (41 per cent) receiving streptokinase and 40 of 69 patients (58 per cent) receiving rtPA (P less than 0.05). The time to lysis was significantly shorter with rtPA, median time 22 h, than with streptokinase, median time 40 h (P less than 0.002). There was no difference in the incidence of haemorrhagic complications. These results suggest that rtPA is superior to streptokinase for local intra-arterial thrombolysis.

An audit of lower limb arteriography in diabetic patients

The outcome of 83 diabetic patients with peripheral vascular disease who underwent arteriography between 1984 and 1988 was reviewed. Angioplasty was possible in 42 legs and was technically successful in 31 but led directly to clinical improvement in only 15. Five of 20 patients referred for vascular surgery also improved. Factors associated with a clinically successful outcome were presentation with claudication, palpable pulses in the contralateral foot, and radiographic evidence of either a short proximal lesion or 2-3 vessel run-off. Median life expectancy following arteriography was 36 months. The median time to amputation was 21 months and median survival with both life and limb intact was only 13 months.

Case report: occlusion of subclavian artery treated by percutaneous angioplasty

Percutaneous transluminal angioplasty (PTA) has been shown to be an effective method of treatment of subclavian artery stenoses. We report a case in which a subclavian artery occlusion was successfully treated by this method.