Vascular anomalies: classification, imaging characteristics and implications for interventional radiology treatment approaches

The term vascular anomaly represents a broad spectrum of vascular pathology, including proliferating vascular tumours and vascular malformations. While the treatment of most vascular anomalies is multifactorial, interventional radiology procedures, including embolic therapy, sclerotherapy and laser coagulation among others, are playing an increasingly important role in vascular anomaly management. This review discusses the diagnosis and treatment of common vascular malformations, with emphasis on the technique, efficacy and complications of different interventional radiology procedures.

Catheter-directed gastric artery chemical embolization suppresses systemic ghrelin levels in porcine model

PURPOSE

To prospectively test, in a porcine model, the hypothesis that catheter-directed gastric artery chemical embolization (GACE) can result in suppression of systemic ghrelin levels and affect weight gain.

MATERIALS AND METHODS

This study, which had Animal Care and Use Committee approval, was performed in healthy, growing swine (weight range, 40-45 kg; n = 10). GACE was performed in five swine with the infusion of sodium morrhuate (125 mug) selectively into the gastric arteries that supply the fundus. Five control animals underwent a sham procedure with 5 mL of saline. Weight and fasting plasma ghrelin levels were obtained in animals at baseline and in weeks 1-4. Statistical testing for substantial differences in ghrelin blood levels over time and between treated and untreated animals was performed by using a cross-sectional time-series linear model with feasibility generalized least squares.

RESULTS

The pattern of the change in ghrelin levels over time was significantly different between control and treated animals (P < .004). In treated animals, ghrelin levels were significantly reduced at week 1 (mean, 664.1 pg/mL +/- 103.1 [standard error of the mean], P < .02), week 2 (mean, 618.1 pg/mL +/- 180.4, P < .001), week 3 (mean, 578.4 pg/mL +/- 214.9, P < .001), and week 4 (mean, 876.6 pg/mL +/- 228.6, P < .03) relative to baseline (mean, 1006.3 pg/mL +/- 190.1). The percentage change in serum ghrelin values in swine treated with GACE decreased from baseline to -34%, -38.6%, -42.5%, and -12.9% during weeks 1-4, respectively. In control swine, percentage change in serum ghrelin was -1.7%, -9.7%, +2.6%, and +18.2% during weeks 1-4, respectively. At the end of 4 weeks, control swine continued to gain weight, with a 15.1% increase from their original weight, while the weight in swine treated with GACE plateaued at an increase of 7.8% from the original weight.

CONCLUSION

Catheter-directed GACE can suppress the appetite hormone ghrelin and affect weight gain.

Catheter-directed gastric artery chemical embolization for modulation of systemic ghrelin levels in a porcine model: initial experience

PURPOSE

To prospectively test, in a porcine model, the hypothesis that use of catheter-directed gastric artery chemical embolization (GACE) can result in substantial suppression of systemic ghrelin levels.

MATERIALS AND METHODS

The institutional animal care and use committee approved this study. Adult healthy swine (40-45 kg, n=8) were tested. GACE was performed by infusing morrhuate sodium selectively into the left gastric artery. Six swine (animals A-F) underwent left GACE by using a dose-escalating regimen of morrhuate sodium, whereas two control swine underwent a sham procedure. Weight and fasting plasma ghrelin levels were compared in swine at baseline and at weeks 1-4. At week 4, stomachs were excised and analyzed. Analysis of the change in ghrelin values and weight was performed with both paired t test and unpaired Student t test.

RESULTS

In control swine (n=2), there was no significant difference in ghrelin values before (844.8 pg/mL +/- 40 [standard deviation]) and after (997 pg/mL +/- 93) the procedure (P=.5). Swine that received a low dose of morrhuate sodium (animals A-D) showed a significant increase in serum ghrelin values from 683.7 pg/mL +/- 241 to 1555.9 pg/mL +/- 312 (P=.002). At a higher dose, the mean baseline ghrelin values decreased from 466 pg/mL to 187 pg/mL +/- 162. Weight changes of +1.4% and +8.6% were seen in swine that underwent GACE and control swine, respectively. Histochemical staining showed preservation of overall tissue architecture and parietal cells.

CONCLUSION

Use of GACE can result in increased or suppressed ghrelin levels.

Role of image-guided vascular intervention in therapeutic angiogenesis translational research

Therapeutic angiogenesis, the process of growing collateral blood vessels to better perfuse ischemic tissue, has been hailed as an up-and-coming treatment for symptomatic lower-extremity peripheral arterial occlusive disease. A minimally invasive durable treatment would be welcome since current treatment options for this disease carry high risk, limited efficacy or limited durability. Unfortunately, as evidenced by disappointing results in multiple clinical trials, therapeutic angiogenesis has yet to deliver in humans the success it has seen in animal models. In this review, we discuss the challenges of translating therapeutic angiogenesis into effective clinical treatments for lower-extremity peripheral arterial occlusive disease and we highlight the role that experts in image-guided vascular interventions can play in advancing the field.

Who needs the surgical headlight?

OBJECTIVE

The use of surgical headlights may lead to awkward posture and limit the mobility and visibility of the operating team. Despite the vast availability of fiber-optic instruments, many surgeons continue to use the surgical headlight, which may be harmful to their health and career. We report the use of the Lumitex LightMat surgical illuminator instead of the conventional surgical headlight in cleft palate surgery.

METHODS

The LightMat is a disposable single-use device that is bright, flexible, and malleable and attaches easily to most retractors. Twenty cleft palate and five pharyngeal flaps cases were performed in which the LightMat was attached to the Dingman mouth retractor with biocompatible two-sided adhesive tapes.

RESULTS

The LightMat was successfully used in all 25 cases. No cases required the surgeon to put on additional lighting such as a headlight. In addition, no cases required the LightMat surgical illuminator to be replaced.

CONCLUSION

The LightMat provides excellent surgical light for cleft palate surgery and pharyngeal procedures. It affords the surgeon several advantages: it provides a cool operative light, flexibility in surgical position, and improved visibility and mobility; the surgeon avoids the delay in obtaining an appropriate working headlight; and, more importantly, it may prevent postural problems that could lead to spinal sprain and disability.

Constitutively active HIF-1alpha improves perfusion and arterial remodeling in an endovascular model of limb ischemia

OBJECTIVE

Hypoxia-inducible factor 1 (HIF-1) regulates the expression of angiogenic growth factors. We analyzed the effect of intramuscular (i.m.) delivery of AdCA5, an adenovirus encoding a constitutively active form of the HIF-1alpha subunit, in a novel model of limb ischemia.

METHODS

AdCa5 or AdLacZ (6 x 10(8) pfu) was injected into male New Zealand White rabbits that were untreated or subjected to occlusion of the left superficial femoral artery by endovascular coils. Expression of mRNAs was quantified 1, 3, and 7 days after adenovirus injection into rabbits without occlusion. Calf blood pressure (BP), angiography, and immunohistochemical analyses were performed 14 days after arterial occlusion and adenovirus injection.

RESULTS

AdCA5 increased the expression of HIF-1alpha, monocyte chemotactic protein-1, placental growth factor, platelet-derived growth factor B, stromal-derived factor 1alpha, and vascular endothelial growth factor (VEGF) mRNA as well as HIF-1alpha and VEGF protein. On day 14, AdCA5-injected limbs showed improved calf BP ratios (0.89+/-0.13 vs. 0.51+/-0.05, p=0.02), angiographic perfusion scores (3.50+/-0.56 vs. 8.33+/-1.31, p=0.007), and distal deep femoral artery diameter ratio (1.84+/-0.25 vs. 0.93+/-0.22, p=0.02) relative to those receiving AdLacZ. The capillary/myocyte ratio (0.93+/-0.03 vs. 0.78+/-0.06, p=0.04) and arterial luminal area (0.32+/-0.05 mm2 vs. 0.21+/-0.03 mm2, p=0.04) were significantly increased in the AdCA5 group.

CONCLUSION

In a model that resembles atherosclerotic obstruction of peripheral arteries in patients, the i.m. administration of AdCA5 promoted arteriogenic and angiogenic responses.

Endovascular Model of Rabbit Hindlimb Ischemia: A Platform to Evaluate Therapeutic Angiogenesis

PURPOSE

Current animal hindlimb ischemia models involve surgical ligation of the femoral artery and delivery of therapeutic angiogenic agents into the adductor compartment. The authors hypothesize that an endovascular model of hindlimb ischemia would be a more appropriate platform, closely resembling atherosclerosis by occluding the vessel from within, causing less inflammation, wound healing and subsequent collateralization.

MATERIALS AND METHODS

The left superficial femoral artery in 17 rabbits was occluded by endovascular coil embolization (n=9) or surgical ligation (n=8). Animals (n=3; in each group) were sacrificed on day 3 to determine the arteriolar luminal area, number of arterioles, microsphere determined perfusion, and degree of inflammation. On day 28, the remaining animals underwent calf blood pressure measurements and angiography to determine the number of collaterals and diameter of vessels supplying the hindlimb.

RESULTS

Immediate postprocedure (day 0) and presacrifice (day 3 or 28) occlusion rates were 89% (eight of nine rabbits) and 100% for the endovascular model; 100% and 100% for the surgical model, respectively. Hindlimb paralysis and muscle atrophy was found in one surgical animal. On day 3, there was an increase in hindlimb perfusion (surgery, 0.04+/-0.01; endovascular, 0.02+/-0.01; P=.02), an increase in arteriolar luminal area (surgery, 481 microm+/-240; endovascular, 345 microm+/-151; P=.04), and a trend toward more inflammation (surgery, 5.5+/-3.8; endovascular, 2.5+/-3.0; P=.08) in the surgical group. There was no difference in number of vessels between both groups. On day 28 there was no difference in the calf blood pressure ratios or in the number of collaterals. However, there was enlargement of the distal profunda femoris artery, the vessel closest to the surgical incision, in the surgical group (L/R ratio: immediate post-occlusion, 1.06+/-0.11; day 28, 1.27+/-0.08; P=.02).

CONCLUSION

The endovascular model was efficacious in providing occlusion of the superficial femoral artery, and induced less of an arteriogenic response compared with the surgical model. The authors believe that this endovascular model is a superior platform for studying therapeutic angiogenic agents.

Extracorporeal Expulsion of a Vascular Endograft Used to Treat a Mycotic Aneurysm

A 65-year-old woman with a right common iliac artery mycotic aneurysm and an overlying sacral pressure ulcer was treated with placement of a vascular endograft. The mycotic aneurysm was successfully excluded, but 3 months after the procedure, the endograft was expelled through the wound. Fortunately, the patient had minimal clinical sequelae. This case emphasizes the importance of frequent noninvasive imaging of mycotic aneurysms treated with endografts. A rigorous postoperative imaging protocol is proposed based on the current regimen for abdominal aortic aneurysm surveillance after endograft implantation.

Intradermal radioisotope is superior to peritumoral blue dye or radioisotope in identifying breast cancer sentinel nodes

BACKGROUND

Sentinel lymph node (SLN) mapping and biopsy have emerged as the technique of choice for axillary staging of breast cancer. Several methods have been developed to identify SLNs, including peritumoral or intradermal injection of isosulfan blue dye or technetium sulfur colloid (TSC). We hypothesize that intradermal TSC is the optimal mapping technique and can be used alone to identify SLNs.

STUDY DESIGN

From March 1997 through January 2001, 180 women with T1 and T2 invasive breast cancer and clinically negative axilla underwent SLN mapping and biopsy. Peritumoral TSC was injected in 74 patients, 62 of whom also received peritumoral blue dye. Intradermal TSC (above tumor) was performed in 94 patients, 76 of whom also received peritumoral blue dye. Technetium-rich nodes were identified intraoperatively using a hand-held gamma probe and blue nodes were identified visually. Hematoxylin- and eosin-stained SLN sections were examined by light microscopy for breast cancer metastases.

RESULTS

Overall, the SLN mapping procedures were successful in 91% of patients. Peritumoral and intradermal TSC were successful in identifying SLNs in 78% and 97% of patients, respectively. Peritumorally injected isosulfan blue was successful in identifying 83% of SLNs. Intradermal TSC was found to be superior to peritumoral TSC and peritumoral blue dye in identifying SLNs (p = 0.00094, chi-squared, and p = 0.020, ANOVA).

CONCLUSIONS

SLN mapping by intradermal TSC has a significantly higher success rate than peritumoral TSC or blue dye. There was minimal benefit in identifying additional SLNs with addition of peritumoral blue dye to intradermal TSC. So, SLN mapping and biopsy using intradermal-injected TSC can be used alone to effectively stage the axilla for breast cancer.

A U.S. Army Forward Surgical Team’s Experience in Operation Iraqi Freedom

BACKGROUND

The Forward Army Surgical Team (FST) was designed to provide surgical capability far forward on the battlefield to stabilize and resuscitate those soldiers with life and limb threatening injuries. Operation Iraqi Freedom represents the largest military operation in which the FST concept of health care delivery has been employed. The purpose of our review is to describe the experience of the 555FST during the assault phase of Operation Iraqi Freedom.

METHODS

During the 23 days beginning 21 March 2003, data on all patients seen by the 555 FST were recorded. These data included combatant status, injuries according to anatomic location, and operative procedures performed.

RESULTS

During the twenty-three day period, the 555 FST evaluated 154 patients. There were 52 EPWs, 79 U.S. soldiers, and 23 Iraqi civilians treated. Injuries to the lower extremity and chest (48% and 25%) were the most common in the EPW group. Upper extremity and lower extremity injuries were the most common in the civilian (57% and 39%) and U.S. soldier groups (32% and 30%). The number of injured regions per patient were 1.14 for U.S. soldiers, 1.33 for EPWs, and 1.52 for Iraqi civilians (p < 0.003). EPWs had proportionately more thoracic and abdominal injuries than the other groups (p < 0.05).

CONCLUSIONS

Majority of the life threatening injuries evaluated involved EPWs. A combination of body armor and armored vehicles used by U.S. soldiers limited the number of torso injuries presenting to the FST. Early resuscitation and stabilization of U.S. soldiers, EPWs, and civilians can be successfully accomplished at the front lines by FSTs. Further modification of the FST's equipment will be needed to improve its ability in providing far forward surgical care.

Effect of age on the contraction of pulmonary venous sphincters in rats

Pulmonary veins of rats have regular focal ringlike muscular constrictions (sphincters) that deepen with stimuli, such as head injury, sufficient to cause pulmonary edema. The depth of the individual constrictions on the veins can be determined by casting the pulmonary circulation, fracturing the cast veins at their narrowed points, and measuring the constriction using a scanning electron microscope. A recent study in rats given a blow to the head showed that the venous constriction was attenuated by alpha-adrenergic antagonism, but interaction between the antagonist, the animal body weight, and sex was found. Older, heavier male animals constricted more. To clarify these factors and assess the change in pulmonary venous sphincter contraction with age, 20 female Sprague-Dawley rats aged 5, 10, 15, 20, and 30 wk had their lung vasculature cast with methyl methacrylate. Of the 4 animals in each age group 3 were given a blow to the head to constrict the veins while the plastic was solidifying. The lungs were digested and the casts of the blood vessels were fractured, exposing the constricted portions of the veins. The depths of these focal constrictions were measured. In animals that received the head blow the constrictions were 2.9 +/- 0.3% (5 wk), 4.1 +/- 0.3% (10 wk), 5.8 +/- 0.4% (15 wk), 6.8 +/- 0.4% (20 wk), and 7.1 +/- 0.5% (30 wk) (p < 0.0001). To separate age from weight, a multivariate regression that accounted for venous contraction was carried out. Although head blow, age, and weight were each individually important, the combined model showed age was insignificant (p = 0.9) when weight (p = 0.02) was present.(ABSTRACT TRUNCATED AT 250 WORDS)