External polytetrafluoroethylene reinforcement of varicose autologous vein grafts in peripheral bypass surgery produces durable bypass function.

OBJECTIVE: Use of autologous veins as peripheral bypass graft may become critical in the presence of significant varicose degeneration of the harvested vein. External support of such dilated veins with standard polytetrafluoroethylene (PTFE) prostheses was recommended as an option to use these veins for peripheral bypass. A single-center experience with this technique regarding long-term graft function, secondary reinterventions, and potential graft degeneration is presented. METHODS: Between January 1995 and January 2006, there were 54 patients with varicose veins who underwent 57 consecutive infrainguinal vein bypass operations with PTFE reinforcement in 57 limbs. Indications for surgery consisted of disabling claudication (5), chronic critical ischemia (40), popliteal aneurysm (11), and acute ischemia (1). Grafts were observed with duplex ultrasound scan supplemented by additional angiography in case of recurrent ischemia, with prospective documentation of follow-up data in a computerized vascular database. Graft patency, limb salvage, and possible degeneration of the vein grafts were retrospectively analyzed. RESULTS: Mean follow-up was 79 months (range, 1-219 months). The 30-day mortality was 2%. Secondary procedures to maintain or to restore bypass patency were necessary in 12 grafts (21%). Primary, primary assisted, and secondary patency rates were 54%, 73%, and 73% after 5 years for all bypasses, with a limb salvage rate for limbs operated on for chronic critical or acute ischemia of 83%. Significant stenosis of a reinforced vein segment was detected in one case after 56 months, with subsequent replacement of the vein graft with a biologic vascular prosthesis. CONCLUSIONS: Good late graft patency and limb salvage combined with a low rate of late vein graft degeneration justify the use of external PTFE reinforcement of varicose vein segments in infrainguinal bypass surgery.

Ten-year follow-up of endovascular aneurysm treatment with Talent stent-grafts.

The purpose of this study was to evaluate the clinical results, complications, and secondary interventions during long-term follow-up after endovascular aneurysm repair (EVAR) and to investigate the impact of endoleak sizes on aneurysm shrinkage. From 1997 to March 2007, 127 patients (12 female, 115 male; age, 73.0 +/- 7.2 years) with abdominal aortic aneurysms were treated with Talent stent-grafts. Follow-up included clinical visits, contrast-enhanced MDCT, and radiographs at 3, 6, and 12 months and then annually. Results were analyzed with respect to clinical outcome, secondary interventions, endoleak rate and management, and change in aneurysm size. There was no need for primary conversion surgery. Thirty-day mortality was 1.6% (two myocardial infarctions). Procedure-related morbidity was 2.4% (paraplegia, partial infarction of one kidney, and inguinal bleeding requiring surgery). Mean follow-up was 47.7 +/- 34.2 months (range, 0-123 months). Thirty-nine patients died during follow-up; three of the deaths were related to aneurysm (aneurysm rupture due to endoleak, n = 1; secondary surgical reintervention n = 2). During follow-up, a total of 29 secondary procedures were performed in 19 patients, including 14 percutaneous procedures (10 patients) and 15 surgical procedures (12 patients), including 4 cases with late conversion to open aortic repair (stent-graft infection, n = 1; migration, endoleak, or endotension, n = 3). Overall mean survival was 84.5 +/- 4.7 months. Mean survival and freedom from any event was 66.7 +/- 4.5 months. MRI depicted significantly more endoleaks compared to MDCT (23.5% vs. 14.3%; P < 0.01). Patients in whom all aneurysm side branches were occluded prior to stent-grafting showed a significantly reduced incidence of large endoleaks. Endoleaks >10% of the aneurysm area were associated with reduced aneurysm shrinkage compared to no endoleaks or <10% endoleaks (Delta at 3 years, -1.8% vs. -12.0%; P < 0.05). In conclusion, endovascular aneurysm treatment with Talent stent-grafts demonstrated encouraging long-term results with moderate secondary intervention rates. Primary occlusion of all aortic side branches reduced the incidence of large endoleaks. Large endoleaks significantly impaired aneurysm shrinkage, whereas small endoleaks did not.

Questionable value of adjuvant arteriovenous fistula in pedal bypass at high risk for early failure.

Results of an adjuvant arteriovenous fistula (AVF) in pedal bypass surgery in the presence of poor status of the recipient artery, severely impaired intraoperative runoff, or revision for early failure and flow restitution were analyzed in a retrospective study. From January 1998 to December 2006, 24 adjuvant AVFs were constructed in autologous vein or composite pedal bypasses with low intraoperative bypass flow, poor status of the pedal artery, or during successful early bypass revision to prevent graft failure. All infrainguinal bypass operations were registered in a computerized database and prospectively followed. Pedal bypasses with adjunctive AVF were reviewed for fistula function, graft patency, limb salvage, and patient survival. Primary and secondary bypass patency rates at 1 year were 59% and 77%, respectively, with an AVF patency of 36%. Four legs were amputated despite a patent bypass with patent AVF on three occasions. The corresponding limb salvage rate was 65% at 1 year. Patient survival was 50% at 3 years. Adjuvant AVF constructed in grafts considered at high risk for early failure in pedal vein graft or composite bypass does not seem to prevent future graft failure. In patent bypasses the fistula has a significant tendency for spontaneous occlusion. It may be considered in the use of prosthetic composite pedal grafts in selected cases.

Femoropopliteal prosthetic bypass with glutaraldehyde stabilized human umbilical vein (HUV).

OBJECTIVE: Femoropopliteal bypass still is the standard surgical therapy for disabling claudication and critical ischemia. When autologous vein is not suitable synthetic or biological prostheses may be considered. Second generation glutaraldehyde tanned human umbilical vein (HUV) graft was chosen for above and below knee femoropopliteal bypass when autologous vein was not available. A single center experience regarding long-term graft function, secondary reinterventions, and potential biodegeneration of the HUV is presented. METHODS: Between January 1994 and January 2005, 211 consecutive femoropopliteal bypass operations with HUV (65 above knee and 146 below knee) were performed in 197 patients for disabling claudication (57), chronic critical ischemia (130), popliteal artery aneurysm (9), acute ischemia (14), or aneurysmal degeneration of a synthetic graft (1) in the absence of suitable ipsilateral great saphenous vein. Grafts were followed with duplex scan supplemented by additional angiography in case of recurrent ischemia with prospective documentation of follow-up data in a computerized vascular database. Surveillance of the HUV included routine evaluation of potential biodegeneration with duplex scan. Retrospective analysis of graft patency, limb salvage, and signs of aneurysmal degeneration was performed. RESULTS: Mean (median) follow-up was 44 (35) months (range 1 to 143 months). Thirty-day mortality was 2.4%. Early postoperative bypass thrombosis after a median of 4 days postoperatively (0 to 30 days) prompted revision with thrombectomy in 16% of cases. Besides late bypass thrombosis in 14.7%, additional operative or endovascular reinterventions during follow-up to maintain or restore graft patency was necessary in 8.5% of bypasses. Primary, primary assisted, secondary patency rate, and limb salvage rate after 5 years were 54%, 63%, 76%, and 92%, respectively, for all bypasses with no significant difference between above and below knee anastomosis. Duplex scan identified segmental aneurysmal degeneration in six grafts, which led to operative reintervention in three cases. The rate of detected aneurysm for grafts patent for more than three years was 7% with a rate of reintervention for aneurysm of 3.5%. CONCLUSION: Although a considerable rate of early thrombotic occlusions occurred, excellent secondary graft patency and limb salvage combined with a tolerable rate of late aneurysmal degeneration detected by means of duplex scan surveillance justify the use of the HUV in femoropopliteal bypass surgery when ipsilateral autogenous vein is not suitable.

Ischemia-Reperfusion Injury : Pathophysiology and Clinical Implications.

The term ischemia-reperfusion injury describes the experimentally and clinically prevalent finding that tissue ischemia with inadequate oxygen supply followed by successful reperfusion initiates a wide and complex array of inflammatory responses that may both aggravate local injury as well as induce impairment of remote organ function. Conditions under which ischemia-reperfusion injury is encountered include the different forms of acute vascular occlusions (stroke, myocardial infarction, limb ischemia) with the respective reperfusion strategies (thrombolytic therapy, angioplasty, operative revascularization) but also routine surgical procedures (organ transplantation, free-tissue-transfer, cardiopulmonary bypass, vascular surgery) and major trauma/shock. Since the first recognition of ischemia-reperfusion injury during the 1970s, significant knowledge has accumulated and the purpose of this review is to present an overview over the current literature on the molecular and cellular basis of ischemia-reperfusion injury, to outline the clinical manifestations and to compile contemporary treatment and prevention strategies. Although the concept of reperfusion injury is still a matter of debate, it is corroborated by recent and ongoing clinical trials that demonstrated ischemic preconditioning, inhibition of sodium-hydrogen-exchange and administration of adenosine to be effective in attenuating ischemia-reperfusion injury.

Long-term outcome after Talent endograft implantation for aneurysms of the abdominal aorta: a multicenter retrospective study.

BACKGROUND: The development of newer-generation endografts for the endovascular treatment of abdominal aortic aneurysms has resulted in considerable improvements in clinical performance. However, long-term outcome data are still scarce. To assess long-term clinical and radiographic outcomes after use of the Talent stent graft, a retrospective analysis was performed that was based on 165 patients treated with this endograft in Germany between October 1996 and December 1998. METHODS: Data were collected according to the recommendation of the ad hoc committee for standardized reporting practices in vascular surgery and were evaluated statistically by using univariate and multivariate analyses. RESULTS: A total of 165 patients were treated with a Talent endograft in 9 German centers before December 31, 1998. Most were asymptomatic (94.5%), male (97.6%), and treated with a bifurcated graft (86.7%). Two patients (1.2%) died within 30 days, and 28 (17%) died during the follow-up period. The cause of death was aneurysm rupture in one case. Survival was 95.4% +/- 1.7% at 1 year, 89% +/- 2.6% at 2 years, 78.1% +/- 3.6% at 5 years, and 76.2% +/- 4.1% at 7 years. Patients classified as American Society of Anesthesiologists grade IV had a significantly lower survival rate (24.9%) than those classified as American Society of Anesthesiologists grade II and III (91.9% and 77.3%). During a mean follow-up period of 53.2 +/- 20.1 months (range, 1-84 months), 47 secondary procedures were performed in 31 patients (18.8%). Kaplan-Meier estimates showed a freedom from secondary intervention of 94.7% +/- 1.8%, 81.7% +/- 3.3%, and 77.4% +/- 3.6% at 1, 3, and 7 years, respectively. The reason for secondary treatment was endograft thrombosis in 10 patients (6.1%), persisting primary endoleak in 9 (5.5%), late secondary endoleak in 6 (3.6%), graft migration in 3 (1.8%), aneurysm rupture in 2 (1.2%), and graft infection in 1 (0.6%). Device migration (> or =10 mm) occurred in seven patients (4.2%). Other graft changes, such as graft kinking (n = 4; 2.4%), fracture of metallic stents (n = 2; 1.2%), erosion of the longitudinal bar (n = 2; 1.2%), or modular component separation (n = 1; 0.6%), were rare. Follow-up computed tomographic imaging revealed a decrease of the maximum aneurysm sac diameter (>5 mm) in 106 (64.2%) patients and an increase in 14 (8.5%) patients. The mean aneurysm diameter significantly decreased (P < .001). Of the factors recorded at baseline, only endoleaks showed a significant correlation with the risk of aneurysm increase during follow-up (P < .001). Adverse anatomy (neck diameter >28 mm, neck length <15 mm, and '5 patent aortic branches) did not adversely influence the aneurysm shrinkage rate, the risk for a secondary procedure, or the clinical success rate. A significantly higher rate of clinical success (P < .05) was observed in patients older than 65 years of age. CONCLUSIONS: Implantation of the Talent endograft device is a safe and effective alternative to open surgery for exclusion of abdominal aortic aneurysm. In comparison with first-generation grafts, the device showed superior durability for as long as 5 to 7 years after implantation. Even if prototypes of the Talent device were implanted in this study, the graft was also successfully used in most patients, even in those with adverse anatomy. Because improvements of the endograft have been made to address connecting bar breaks, a lower incidence of graft limb occlusion can be expected in the future.

MRI versus helical CT for endoleak detection after endovascular aneurysm repair.

OBJECTIVE: The objective of our study was to investigate the diagnostic accuracy of MRI and helical CT for endoleak detection. SUBJECTS AND METHODS: Fifty-two patients underwent endovascular aneurysm repair with nitinol stent-grafts. Follow-up data sets included contrast-enhanced biphasic CT and MRI within 48 hr after the intervention; at 3, 6, and 12 months; and yearly thereafter. The endoleak size was categorized as < or = 3%, > 3% < or = 10%, > 10% < or = 30%, or > 30% of the maximum cross-sectional aneurysm area. A consensus interpretation of CT and MRI was defined as the standard of reference. RESULTS: Of 252 data sets, 141 showed evidence for endoleaks. The incidence of types I, II, and III endoleaks and complex endoleaks was 3.2%, 40.1%, 8.7%, and 4.0%, respectively. The sensitivity for endoleak detection was 92.9%, 44.0%, 34.8%, and 38.3% for MRI, biphasic CT, uniphasic arterial CT, and uniphasic late CT, respectively. The corresponding negative predictive values were 91.7%, 58.4%, 54.7%, and 56.1%, respectively. The overall accuracy of endoleak detection and correct sizing was 95.2%, 58.3%, 55.6%, and 57.1% for MRI, biphasic CT, uniphasic arterial CT, and uniphasic late CT, respectively. CONCLUSION: MRI is significantly superior to biphasic CT for endoleak detection and rating of endoleak size, followed by uniphasic late and uniphasic arterial CT scans. MRI shows a significant number of endoleaks in cases with negative CT findings and may help illuminate the phenomenon of endotension. Endoleak rates reported after endovascular aneurysm repair substantially depend on the imaging techniques used.

Colocalization of oxidized low-density lipoprotein, caspase-3, cyclooxygenase-2, and macrophage migration inhibitory factor in arteriosclerotic human carotid arteries.

Apoptotic and inflammatory processes occur in human arteriosclerotic lesions. We examined the hypothesis whether both processes are possibly associated by studying the colocalization of corresponding markers. In 11 human arteriosclerotic carotid arteries, proapoptotic markers (CPP32 (caspase-3), poly(ADP-ribose) polymerase, apoptosis-inducing factor, c-Jun/AP-1, and p53) and proinflammatory markers (macrophage migration inhibitory factor (MIF) and cyclooxygenase-2) were found in macrophages (MPhi) evaluated by computer-assisted immunohistomorphometry. Double-labeling studies demonstrated a colocalization of, both, proapoptotic and proinflammatory markers in these MPhi. Moreover, these MPhi also contained oxidized low-density lipoproteins (oxLDL). Exposure of cultured human MPhi to oxLDL, C6-ceramide, and tumor necrosis factor-alpha or H2O2 resulted in a significant increase of the apoptosis rate as well as of the MIF protein expression. Our study of MPhi in arteriosclerotic carotid arteries and in vitro experiments provide evidence that markers of apoptosis and inflammation are not only significantly increased but are also coexpressed. We conclude there are reciprocal modulatory interactions between apoptotic and inflammatory pathways in human plaque MPhi, which might importantly modify plaque progression or stability.

Involvement of growth differentiation factor-15/macrophage inhibitory cytokine-1 (GDF-15/MIC-1) in oxLDL-induced apoptosis of human macrophages in vitro and in arteriosclerotic lesions.

Growth differentiation factor-15/macrophage inhibitory cytokine-1 (GDF-15/MIC-1) is a new member of the transforming growth factor beta (TGF-beta) superfamily, which has most recently been found in activated macrophages (MPhi). We have now investigated GDF-15/MIC-1 in human MPhi after exposure to oxidized low-density lipoproteins (oxLDL) related mediators in vitro and in arteriosclerotic carotid arteries. Using RT-PCR and Western blotting a pronounced induction of GDF-15/MIC-1 expression by oxLDL, C6-ceramide, tumor necrosis factor (TNFalpha) and hydrogen peroxide (H2O2) was found in cultured human MPhi. In 11 human arteriosclerotic carotid arteries, immunohistochemical analyses supported by computer-assisted morphometry and regression analyses demonstrated a significant colocalization of GDF-15/MIC-1 immunoreactivity (IR) with oxLDL IR and manganese superoxide dismutase (MnSOD) IR in CD68 immunoreactive (ir) MPhi, which were also expressing AIF-IR (apoptosis-inducing factor), caspase-3-IR (CPP32), PARP-IR, c-Jun/AP-1-IR and p53-IR. Our data suggest that GDF-15/MIC-1 is inducible in human MPhi by oxLDL and its mediators in vitro and is supposed to contribute to oxidative stress dependent consequences in arteriosclerotic plaques, e.g. modulating apoptosis and inflammatory processes in activated MPhi.

Magnetic resonance angiography unmasks reliable target vessels for pedal bypass grafting in patients with diabetes mellitus.

OBJECTIVE: The purpose of this study was to evaluate the performance of pedal bypass grafts to foot vessels detected by magnetic resonance angiography (MRA) that were occult in conventional angiography in patients with diabetes mellitus and severe arterial occlusive disease. METHODS: Vascular surgery and radiology registries were reviewed for patients with pedal bypass grafts to arteries that were not detected with digital subtraction angiography but unmasked with MRA. From December 1997 to March 1999, 15 patients (mean age, 73 +/- 8 years) were identified and analyzed retrospectively. All the patients were diabetic, with 60% being insulin-dependent. Advanced tissue loss was the operative indication in all the cases. Distal anastomosis was performed to the dorsalis pedis artery in 10 cases and to the plantar artery in five cases, with ipsilateral greater saphenous vein as graft material in all the cases. RESULTS: The perioperative mortality rate was 7% (1 of 15 cases). One graft occlusion resulted in a secondary patency rate of 93.1%. During a mean follow-up examination period of 22 months, no graft occlusions and one major amputation were noted, which resulted in a secondary patency rate of 93.1% and a limb salvage rate of 89.5% at 36 months. CONCLUSION: Foot vessels that were occult in conventional angiography but could be detected with MRA were shown to be suitable target vessels for pedal bypass grafting with promising results.

[Endovascular aneurysm therapy--long-term treatment outcomes after 7 years]. / Endovaskuläre Aneurysmatherapie--Langzeitergebnisse nach 7 Jahren.

BACKGROUND: Stentgrafts for endovascular treatment of abdominal aortic aneurysms (AAA) have been commercially available since 1994, with now large numbers of implantations all over the world. PATIENTS AND METHODS: From 1994-2001, 115 patients were treated with Stentor, Vanguard and Talent stentgrafts in our institution. RESULTS: Late complications of the first- and second-generation stentgrafts as radiologic or surgical interventions to maintain complete exclusion of the aneurysm amounted to 30% with an additional 22% for observed endoleaks and configuration changes of the stentgraft. Third-generation stentgrafts had a lower complication rate of 12.2% for interventions and 18.3% for late endoleaks and graft changes. CONCLUSION: High costs of the devices, a pretty high late complication rate, and the uncertain maintenance of stentgraft function to prevent aneurysm rupture currently limit the widespread application of this new technology, leaving conventional aneurysmectomy the standard for aneurysm treatment and reserving the endovascular method for selected patients.

[Pedal bypass surgery in diabetic foot syndrome: indications, technique and outcome]. / Pedale Bypasschirurgie beim diabetischen Fusssyndrom: Indikation, Technik und Ergebnisse.

Peripheral arterial occlusive disease in the diabetic patients is characterized predominantly by long segmental occlusion of the tibial arteries with patent segments of pedal arteries. Neuropathy and high susceptibility for foot infection explain the dramatically increased risk of major amputation. The pattern of arteriosclerotic disease allows construction of pedal bypasses especially by the use of short autologous vein grafts employing distal origin of the bypass. Indication and performance of the bypass procedure rely on a complete angiographic evaluation of the arterial system of the diseased limb. Besides the dorsalis pedis artery with its major branches as preferentially used recipient vessel, the posterior tibial artery and its plantar branches may be anastomosed. Thus, improved foot perfusion will allow necessary minor amputations with safe wound healing. The use of autologous vein grafts is associated with a high late patency rate of more than 70% and a late limb salvage rate of more than 80%. Pedal artery bypass grafting should routinely be part of the therapeutic strategies in advanced diabetic foot syndrome with critical limb ischemia and impending limb loss.