Comparison of Quantification Methods of111In-Labelled Platelet Deposition in Peripheral Bypass Grafts

The action of antithrombotic drugs can be evaluated by measuring the deposition of111In-labelled platelets on peripheral bypass grafts several days after injection. This evaluation can be performed qualitatively (visual interpretation on the daily images) or quantitatively. Four different methods which calculate the ratio of platelet uptake with a reference region are compared: two methods use a gamma camera and two a detector. A blood sample or the region under the sternal angle are used as reference. The daily ratio of the counts, recorded by a gamma camera in a region of interest covering the graft, and the blood radioactivity interpolated from a platelet survival curve appears to be the most reliable method. The information of all the ratios can be combined in a single thrombogenicity index which reflects the daily rise of a linear or exponential regression versus time.

Outcome and One Year Follow-up of Intra-arterial Staphylokinase in 191 Patients with Peripheral Arterial Occlusion

Wild-type or equipotent variants of recombinant staphylokinase (rSak) were given intra-arterially (as a 2 mg bolus injection followed by an infusion of 1 mg/h or 0.5 mg/h overnight, with concomitant heparin [1000 IU/h]) to 191 patients of less than 80 years (62 ± 1 years, mean ± SEM), with a peripheral arterial occlusion (PAO) of less than 120 days (mean 14 ± 1 days, median 11 days, 5 to 95 percentiles 3 to 30 days). Ninety nine patients presented with acute or subacute ischemia, 57 with severe claudication, 33 with chronic rest pain and 2 with gangrene. Occlusion occurred in 122 native arteries and in 69 grafts. Revascularization was complete in 83 percent (158/191), partial in 13 percent (24/191) and absent in 4 percent (7/191) after administration of 12 ± 0.5 mg rSak over 14 ± 0.7 h. Complete revascularization of acute occlusions of popliteal or more distal arteries was less frequent (60 percent, 15/25) than of acute occlusions of more proximal native arteries (95 percent, 37/39, p <0.001) or grafts (89 percent, 50/56, p = 0.005). Additional endovascular procedures were performed in 47 percent and subsequent elective bypass surgery in 23 percent of patients. Major bleeding occurred in 12 percent (23/191), one month mortality was 3.1 percent (6/191) and one year mortality was 6.9 percent (12/174). However, four patients (2.1 percent) had an intracranial bleeding following therapy: a 85 year old woman with severe diabetic arteriopathy, who was included in violation of the protocol, a 79 and a 74-year-old woman and a 74-year-old man, all with severe hypertension and limb threatening ischemia; these four patients died within two months after treatment. Amputations were performed within the first year in 16 of 162 surviving patients (9.8 percent): in 7 percent (7/96) with an occluded native artery and 14 percent (9/66) with an occluded graft (p = 0.19). No significant difference in lysis rate, one month mortality or one year amputation-free survival was observed in occlusions of recent onset (<14 days, n = 126) as compared to occlusions of longer duration (<14 days, n = 65). Treatment was interrupted prematurely in 4 patients because of a suspected allergic reaction. Fibrinogen levels remained unaffected during treatment (3.3 ± 0.1 g/l before vs. 3.3 ± 0.1 g/l after infusion, n = 167).

In conclusion, rSak appears to be a highly effective thrombolytic agent in patients with PAO, resulting in a low one month mortality (3.1 percent) and a high one year amputation free survival (84 percent), with an acceptable incidence of major bleedings, but with occasional fatal intracranial hemorrhages.

Banking and Distribution of Large Cryopreserved Arterial Homografts in Brussels: Assessment of 4 Years of Activity by the European Homograft Bank (EHB) with Reference to Implantation Results in Reconstruction of Infected Infrarenal Arterial Prostheses and Mycotic Aneurysms

In 1991 European Homograft Bank (EHB) initiated a program of cryopreservation and distribution of large arteries to meet a new demand for quality-controlled arterial homo grafts of various sizes. From May 1991 to June 1995, 308 arteries have been registered from 136 donors: 122 brain death cases and 14 cadavers (mean age 34 years, male/female ratio 1.52/1); 263 arteries were cryopreserved (113 aortas, 64 aortic bifur cations, and 86 femoral); 19 were discarded for atherosclerosis (6.7%); 10 batches of arteries were partially or totally discarded because of persistent contamination and further eight batches for positive or doubtful viral serology. One hundred patients were treated in nine European centers with one (N = 69) or more EHB homografts. Indications were: infected prosthesis 70 (17 with aortoenteric fistula); mycotic aneurysm 19 (four ascending aortas, two with bronchial fistula); neoplastic infiltration of subrenal aorta one; extracardiac reconstructions/shunts 10. (continued on next page) (Abstract continued) Results from homograft reconstructions in infected prosthesis or mycotic aneurysm were available in 90 patients. There were 19 early deaths and 24 early complications, three were directly graft-related and included a fatal case of homograft rupture. Sixty- seven vascular cases were followed up from 1 month onward (mean: 16 months): 50 were uneventful; there were nine late deaths, of which two resulted from graft-related digestive hemorrhage; there were eight cases of late complications; three arteries were partly explanted as a result of focal thrombosis. Four patients were lost to follow-up. In the cases of aortoenteric fistula, however, the results were disappointing with only five late survivors of the 16 treated patients. Finally, these results show that cryopreserved arteries seem to perform as well in the midterm as the fresh ones.

Both the banking activity of cryopreserved homografts and the short- to mid-term performances of the implants in cases of prosthetic or native arterial infection are very satisfactory, provided no aortoenteric fistula is present. Cryopreserved arteries can also be used for extracardiac shunts and reconstructions.

Endoprosthetic Treatment of a Mycotic Superficial Femoral Artery Aneurysm

Purpose:

To describe the successful stent-graft exclusion of a mycotic aneurysm of the superficial femoral artery.

Case Report:

A 78-year-old man presented with Salmonella arteritis and the formation of a mycotic false aneurysm of the superficial femoral artery. Antibiotics were administered; the aneurysm was excluded using 2 Hemobahn stent-grafts, and the surrounding hematoma was drained. One year postoperatively, there are no clinical or biochemical signs of infection. Ultrasound examination does not show any fluid around the patent stent-graft.

Conclusions:

Stent-graft placement might be an alternative to traditional surgery in selected cases of mycotic aneurysm.

Aorto-iliac stent graft infection complicated by endotension and consequent rupture of the aneurysmal sac: a case report

We present a case report of a bifurcated aorto-iliac stent graft infection two years after implantation. The initial procedure of implantation as well as the patient's recovery was uneventful. Two years later the patient presented with a growing aneurysmal sac without a detectable endoleak and consequent rupture. Instead of graft explantation, we left the graft in situ and performed thorough debridement and an omentoplasty, because of the poor condition of the patient. A Staphylococcus species grew out of the cultures of the aortic wall. The patient recovered well without persistent infection and is still doing well after 43 months. This conservative approach might be an alternative in patients who are deemed to be at high risk for classic graft explantation and an extra-anatomic bypass or in situ bypass.

Does medical specialty influence the treatment of asymptomatic carotid stenosis? a Belgian multidisciplinary survey

AIM

The aim of this study was to supplement the few data that exist regarding the potential effect of the referring medical specialty on the proposed treatment for asymptomatic carotid stenosis.

METHODS

In a web survey, we presented Belgian cardiologists, neurologists and vascular surgeons with two fairly uncomplicated case vignettes on asymptomatic carotid stenosis differing only in the degree of stenosis (70-80% in case 1 and >80% in case 2).

RESULTS

In both cases the suggested therapies were different per medical specialty (P<0.000002 and P<0.00002, respectively). Cardiologists were more conservative and vascular surgeons were more aggressive. Preferred therapies for both cases differed statistically significantly (odds ratio 8.63; 95% confidence interval 5.11-14.58). Suggesting a different therapy or not for case 1 and case 2 was also different per medical specialty (P<0.035). Cardiologists were most inclined to suggest a different therapy and vascular surgeons the least. Nobody switched to a more conservative treatment. Younger physicians suggested a more conservative approach (P<0.014).

CONCLUSION

Different medical specialties prefer different treatments for asymptomatic carotid stenosis. Also, younger physicians seem more conservative. We elaborate on the different reasons that could explain these findings.

Paraparesis after thoracic stent-graft relining for an unrecognized type III endoleak

BACKGROUND

We examined the reasons for missing a type III endoleak on conventional imaging and the pathophysiology of paraparesis after relining this stent graft.

METHODS AND RESULTS

A 46-year-old man was treated with a thoracic stent graft for thoracic rupture of a chronic type B thoracoabdominal dissection with aneurysm formation. In a second intervention, retrograde revascularization of the visceral and renal arteries was performed in combination with insertion of an abdominal stent graft. After initial shrinkage of the aneurysmal sac, the thoracic aortic diameter started increasing again. Consecutive three-phase helical computed tomographic scans did not reveal any endoleak. Because of unbearable back pain, an open surgical exploration was performed. This showed a type III endoleak. Relining of the thoracic stent graft was performed, but paraparesis developed.

CONCLUSION

In patients with unexplained increase of the aneurysmal sac contrast-enhanced magnetic resonance imaging could help to illuminate the underlying endoleak. The collateral network concept can explain spinal cord injury by even minor hemodynamic changes.

Aortoduodenal fistula six weeks after EVAR for abdominal aortic aneurysm: a case report

The technique of endovascular repair of abdominal aortic aneurysm has markedly improved over the years, showing a lower 30-day mortality rate compared to the open technique. Despite improvements, the percentage of reinterventions remains high due to late failure. A rare but severe complication of EVAR is the development of an aortoduodenal fistula, which has a very high mortality rate. The pathogenesis still remains unclear.

Heparin-bonded ePTFE grafts compared with vein grafts in femoropopliteal and femorocrural bypasses: 1- and 2-year results

OBJECTIVE

Many patients with peripheral arterial occlusive disease who require a lower-limb bypass have no available autologous saphenous vein (ASV) for the procedure and thus require a prosthetic graft. Expanded polytetrafluoroethylene (ePTFE) grafts are commonly used, but results with these prostheses have varied, especially when the distal anastomosis is below the knee. However, there is increasing evidence that ePTFE grafts to which heparin has been bound with use of covalent endpoint linkage provide better results. This nonrandomized study compared the performance of these grafts with that of ASV conduits in the largest clinical series of heparin-bonded ePTFE graft implantations reported so far.

METHODS

The records of 350 patients who underwent a lower-limb bypass procedure that used either a heparin-bonded ePTFE graft (n = 240) or an ASV graft (n = 110) were reviewed, and preoperative, operative, and follow-up data were recorded. Kaplan-Meier analyses were used to calculate primary patency and limb salvage rates in the two graft groups; results were compared by using log-rank testing.

RESULTS

The primary patency rates at 1 year for the heparin-bonded ePTFE grafts were 92% for above-knee femoropopliteal (AK FP) bypasses, 92% for below-knee femoropopliteal (BK FP) bypasses, and 79% for femorocrural (FC) applications. The corresponding 2-year rates were 83%, 83%, and 69%, respectively. In the ASV group, the 1-year primary patency rates for AK FP, BK FP, and FC bypasses were 91%, 72%, and 69%, respectively; the 2-year rates were 80%, 72%, and 64%, respectively. There were no significant differences in patency when AK FP, BK FP, or FC procedures were considered separately. Two-year limb salvage rates in the heparin-bonded ePTFE graft group were 92%, 98%, and 87%, respectively, for AK FP, BK FP, and FC bypasses; in the ASV group, the rates were 100%, 91%, and 96%, respectively. Two infections occurred in patients given a heparin-bonded ePTFE graft.

CONCLUSION

In this large retrospective study, heparin-bonded ePTFE grafts had 1- and 2-year primary patency results that were not significantly different from those for ASV grafts. Results in BK FP and FC applications were especially promising. Randomized studies comparing the use of heparin-bonded ePTFE and ASV grafts in the treatment of peripheral arterial disease are needed to substantiate our results.

PEPE II--a multicenter study with an end-point heparin-bonded expanded polytetrafluoroethylene vascular graft for above and below knee bypass surgery: determinants of patency

AIM

The Propaten European Product Evaluation (PEPE II) study was a product evaluation intended to characterize the performance of the GORE PROPATEN vascular graft in above-knee (AK) and below-knee bypass (BK) surgery.

METHODS

This prospective multicenter trial enrolled 142 patients with peripheral arterial disease. In 87 patients AK and in 52 patients BK bypasses (including 15 femorocrural) were implanted (67.6% males, 32.4% females).

RESULTS

The one-year overall primary and secondary patency rates were 80% and 84.7%, respectively. Overall limb salvage rate at 12-months was 96.2%. The primary patency rate for AK bypasses was 82.7%, for BK femoro-popliteal bypasses 74.2% and for BK tibial-peroneal bypasses 79.4%. Secondary patency rates were 87.3%, 78.8% and 85.1%, respectively. Primary patency rates decreased depending on the number of patent run-off vessels (three 84.3%, two 80.8%, one 73.3%). Subgroup analysis showed that female patients had a significantly higher primary patency rate for BK bypasses (95.5% vs. 67.8%, P=0.037 ) compared to male patients. Subgroup analysis comparing patients younger and older than 70 years did not show a statistically significant difference in patency rates. Twenty-one patients underwent 42 reinterventions after bypass surgery.

CONCLUSIONS

Present data show that the end-point heparin-bonded polytetrafluoroethylene graft yields patency rates comparable to those obtained with other graft material in above-knee locations. The encouraging results for BK bypasses suggests that this graft is an excellent option for small diameter vascular reconstructions when autologous vein is unavailable.

Endovascular aneurysm repair or open surgery for treatment of abdominal aortic aneurysm with involvement of both common iliac arteries?

Endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAA) involving the entire common iliac arteries requires proximal coil embolisation of both internal iliac arteries and extension of the stent graft into the external iliac arteries (type E according to the Eurostar classification). A potential complication of this treatment is pelvic ischemia. Therefore, this type of aneurysm is a relative contra-indication for EVAR. In this case-report we describe a hybrid procedure preserving antegrade circulation in one of the internal iliac arteries in a patient with a type E aneurysm who was unfit for open surgery.