11-year experience with anatomical and extra-anatomical repair of mycotic aortic aneurysms.

BACKGROUND: We have reviewed our management, of both ruptured and non-ruptured, abdominal and thoraco-abdominal mycotic aneurysms in order to determine the safety and efficacy of in situ and extra-anatomical prosthetic repairs. METHODS: Data regarding presenting symptoms, investigations, operative techniques and outcome, were collected on patients treated at a singe centre over 11 years. RESULTS: There were 11 men and four women, with a median age of 70 years (range, 24-79). All but one patient were symptomatic and six had a contained leak on admission. In six patients no organisms were identified in either blood or tissue cultures. Pre-operative CT identified; four infra-renal, four juxta-renal, three (Crawford thoraco-abdominal) type IV, three type III and one type II, aortic aneurysms. Thirteen were repaired with in situ prostheses and two required axillo-femoral prosthetic grafts. There were four early deaths. All surviving patients have been followed-up for a median duration of 38 months (range 1/2-112 months). There were two late deaths at 3 months (juxta-renal) and at 2 years (type III), the latter relating to graft infection. CONCLUSIONS: In the absence of uncontrolled sepsis, repair of mycotic aortic aneurysms using prosthetic grafts can achieve durable results.

Haemodynamic effect of intermittent pneumatic compression of the leg after infrainguinal arterial bypass grafting.

BACKGROUND: Intermittent pneumatic compression (IPC) may increase blood flow through infrainguinal arterial grafts, and has potential clinical application as blood flow velocity attenuation often precedes graft failure. The present study examined the immediate effects of IPC applied to the foot (IPC(foot)), the calf (IPC(calf)) and to both simultaneously (IPC(foot+calf)) on the haemodynamics of infrainguinal bypass grafts. METHODS: Eighteen femoropopliteal and 18 femorodistal autologous vein grafts were studied; all had a resting ankle : brachial pressure index of 0.9 or more. Clinical examination, graft surveillance and measurement of graft haemodynamics were conducted at rest and within 5 s of IPC in each mode using duplex imaging. Outcome measures included peak systolic (PSV), mean (MV) and end diastolic (EDV) velocities, pulsatility index (PI) and volume flow in the graft. RESULTS: All IPC modes significantly enhanced MV, PSV, EDV and volume flow in both graft types; IPC(foot+calf) was the most effective. IPC(foot+calf) enhanced median volume flow, MV and PSV in femoropopliteal grafts by 182, 236 and 49 per cent, respectively, and attenuated PI by 61 per cent. Enhancement in femorodistal grafts was 273, 179 and 53 per cent respectively, and PI attenuation was 63 per cent. CONCLUSION: IPC was effective in improving infrainguinal graft flow velocity, probably by reducing peripheral resistance. IPC has the potential to reduce the risk of bypass graft thrombosis.

Renal dysfunction and prolonged visceral ischaemia increase mortality rate after suprarenal aneurysm repair.

BACKGROUND: Elective juxtarenal abdominal aneurysm repair has a significantly lower mortality rate than suprarenal repair. Identification of factors affecting outcome may lead to a reduction in mortality rate for suprarenal repair. METHODS: Data were collected prospectively between 1993 and 2000 for 130 patients who underwent type IV thoracoabdominal aneurysm (TAA) repair and 44 patients who had juxtarenal aneurysm (JRA) repair. Preoperative risk factors and operative details were compared between groups and related to outcome after TAA repair (there were only two deaths in the JRA group). RESULTS: The in-hospital mortality rate was significantly higher following TAA repair (20.0 per cent; 26 of 130 patients) than JRA repair (4.5 per cent; two of 44). Raised serum creatinine concentration was the only preoperative factor (P = 0.013) and visceral ischaemia the only significant operative factor (P = 0.001) that affected mortality after TAA repair. CONCLUSION: JRA repair was performed with similar risks to those of infrarenal aneurysm repair. Impaired preoperative renal function was related to death following TAA repair and conservative treatment should be considered for patients with a serum creatinine level above 180 micromol/l. Reducing the duration of visceral ischaemia might improve outcome.

Increased platelet aggregation and activation in peripheral arterial disease.

OBJECTIVES: patients with peripheral arterial disease (PAD) have a threefold increase in cardiovascular mortality. Standard antiplatelet treatment may not confer uniform benefit in different patient groups. This study aimed to compare platelet function in patients with lower limb PAD, carotid disease and abdominal aortic aneurysm (AAA) with age- and sex-matched healthy controls. METHODS: patients with lower limb PAD (n = 20), carotid disease (n = 40), AAA (n = 13) and age/sex matched healthy controls (n= 20) were studied. Whole blood methods to detect spontaneous platelet aggregation (SPA), and adenosine diphosphate (ADP) and collagen-induced aggregation were used. The detection of platelet P-selectin and the PAC-1 antigen by flow cytometry were also used as markers of platelet activation and aggregation. RESULTS: patients with lower limb PAD or AAA had higher baseline SPA compared to normal controls (p < 0.01). There was significantly higher collagen-induced aggregation in IC patients compared to normal controls (p < 0.01). However, there was no difference in ADP-induced aggregation between lower limb PAD and control patients. There was no difference in PAC-1 binding between control patients and the patients with lower limb PAD, carotid disease or AAA. Patients with carotid disease had a higher expression of P-selectin compared to normal controls (p < 0.05). CONCLUSIONS: this study provides further evidence that platelet hyperactivity is present in patients with PAD despite the use of antiplatelet therapy. Further antiplatelet strategies may be indicated to protect these patients.

Platelet activation during carotid endarterectomy and the antiplatelet effect of Dextran 40.

OBJECTIVE: To determine changes in platelet activation during carotid endarterectomy (CEA) and the antiplatelet effect of Dextran 40. METHODS: Prospective study in 40 patients undergoing CEA. Platelet activity was measured by whole blood flow cytometry and platelet aggregometry during CEA. The expression of P-selectin and the PAC-1 antigen were used as markers of platelet activation and aggregation. Patients received aspirin (75-300 mg) preoperatively and 5,000 units unfractionated heparin during surgery. High intensity transient signals (HITS) in the ipsilateral middle cerebral artery were monitored using transcranial Doppler (TCD) perioperatively. RESULTS: P-selectin expression increased after carotid clamping (P < 0.01) and clamp release (P < 0.05). There was higher expression of PAC-1 after carotid clamping (p < 0.05). Spontaneous and ADP-induced platelet aggregation increased after carotid clamping (P< 0.01) and release (P < 0.01). TCD monitoring showed an increased HITS count from preoperative levels, after clamp release (P < 0.01) and during recovery (P < 0.01). After the operation, patients with more than 50 HITS per 30 min were started on an infusion of dextran 40 (n = 6). P-selectin expression decreased 24 h after dextran 40 (P < 0.01). CONCLUSION: Significant platelet activation and aggregation occurs during CEA despite the current use of antiplatelet treatment. Dextran 40 had an antiplatelet effect after CEA providing further evidence that it may contribute to reducing thromboembolic complications.

Transcription factor NF kappa B expression and postsurgical organ dysfunction.

OBJECTIVE: To examine the role of neutrophil NF kappa B activation in organ dysfunction after major surgery. SUMMARY BACKGROUND DATA: NF kappa B is a transcription factor involved in the signal transduction of many stimuli that may participate in the pathogenesis of sepsis and resultant multiple organ dysfunction syndrome (MODS). It may therefore be a potential target for modulation in the reduction of postsurgical MODS. METHODS: Twenty-five patients undergoing major vascular surgery (thoracoabdominal aortic aneurysm repair) were studied. Perioperative levels of neutrophil NF kappa B, CD11b, and glutathione were measured. In vitro inhibition experiments using NF kappa B inhibitors were also performed. RESULTS: No differences in clinical parameters were apparent before surgery between the patients who subsequently developed MODS and those who did not. However, there was a significant difference in preoperative levels of NF kappa B between the patients who developed postoperative organ dysfunction and those who did not. There was also a significant preoperative difference between patients who survived surgery and those who did not. Glutathione levels were reduced both in patients who developed MODS and those who did not at the onset of surgery. NF kappa B inhibitors suppressed patient plasma-stimulated NF kappa B activation in healthy neutrophils. CONCLUSIONS: Preoperative neutrophil NF kappa B status may be a marker of postoperative outcome after major surgery, and therapy aimed at attenuating neutrophil NF kappa B activation may reduce postoperative sepsis and organ dysfunction.

Warfarin induced skin necrosis.

BACKGROUND: Warfarin induced skin necrosis is a rare complication with a prevalence of 0.01-0.1 per cent. It was first described in 1943. METHODS: A literature review was undertaken using Medline; all relevant papers on this rare compli-cation of warfarin therapy were used. RESULTS: There are several adverse skin manifestations associated with the use of oral anticoagulants, ranging from ecchymoses and purpura, haemorrhagic necrosis, maculopapular vesicular urticarial eruptions to purple toes. This article concentrates mainly on warfarin induced skin necrosis. The syndrome typically occurs during the first few days of warfarin therapy, often in association with the administration of a large initial loading dose of the drug. Although the precise nature of the disease is still unknown, advances in knowledge about protein C, protein S and antithrombin III anticoagulant pathways have led to a better understanding of the mechanisms involved in pathogenesis. Differential diagnosis between warfarin induced skin necrosis and necrotizing fasciitis, venous gangrene and other causes of skin necrosis may be difficult; the disease may also be confused with other dermatological entities. CONCLUSION: Warfarin induced skin necrosis, while rare, is an important complication. All surgeons should be aware of its existence.

Endotoxemia during supraceliac aortic crossclamping is associated with suppression of the monocyte CD14 mechanism: possible role of transforming growth factor-beta1.

PURPOSE: Monocyte CD14 and its soluble form (sCD14) mediate the proinflammatory response to endotoxemia. The aim of this study was to measure the changes to these factors after major aortic surgery and the possible inhibitory role of transforming growth factor-beta(1) (TGF-beta(1)) during these procedures. METHODS: Twenty-four patients with supraceliac aortic crossclamping during thoracoabdominal aortic aneurysm (TAAA) repair and 12 patients with infrarenal aortic crossclamping as part of infrarenal aneurysm repair (AAA) were studied. Blood was collected at incision, aortic clamping, and reperfusion and at 1, 8, and 24 hours after reperfusion. Samples were assayed for endotoxin, peripheral blood monocyte CD14 expression, sCD14, tumor necrosis factor-alpha, and TGF-beta(1). RESULTS: Although there was significant endotoxemia on reperfusion in both groups of patients, peak plasma endotoxin levels were significantly higher in patients with TAAA (P =.001). Monocyte CD14 and plasma sCD14 were significantly decreased in patients with TAAA at reperfusion and 1 hour after reperfusion (P <.01, both points). In patients with AAA, a significant upregulation of CD14 was observed at 24 hours after reperfusion (P <.01), but no significant changes in sCD14 were observed. TNF-alpha showed no significant changes during the study period in both groups. In patients with TAAA, TGF-beta(1) showed significant elevation at all time points (P <.01); whereas in patients with AAA, TGF-beta(1) showed no significant changes. CONCLUSION: Splanchnic ischemia reperfusion in patients who undergo supraceliac aortic clamping is associated with peripheral blood monocyte CD14 suppression and significant elevation of TGF-beta(1). TGF-beta(1) may play an important role in modulating the immune response to endotoxemia during major aortic aneurysm surgery.

Myocardial injury in major aortic surgery.

PURPOSE: The purpose of this study was to examine the effects of major aortic surgery and its associated oxidative stress and injury on the myocardium. METHODS: Plasma from 27 patients who underwent thoracoabdominal aortic aneurysm (TAAA) repair and 17 patients who underwent infrarenal aortic aneurysm (AAA) repair was collected at incision, aortic crossclamping, and reperfusion and 1, 8, and 24 hours thereafter. Samples were assayed for the myocardial specific protein troponin-T, total antioxidant status, and lipid hydroperoxides. RESULTS: Ten patients experienced cardiac dysfunction in the first 24 hours after surgery (eight patients in the TAAA group and two patients in the AAA group). Immediately after reperfusion, total antioxidant status levels dropped in all patients with TAAA and with AAA; this was more marked in patients with TAAA, leading to a significant difference between the two groups at this time point and for up to 1 hour thereafter (P <.01). Patients with TAAA showed a sharp rise in lipid hydroperoxide levels immediately after reperfusion, and levels were significantly higher than in patients with AAA (P =.0007). In patients with AAA, no significant change in troponin-T was observed throughout the study period; whereas in patients with TAAA, levels were significantly elevated at 8 and 24 hours after reperfusion (P <.01). Troponin-T levels significantly correlated with total antioxidant status (r = -0.5) and lipid hydroperoxides (r = 0.78) but not with systolic blood pressure. CONCLUSION: Supracoeliac aortic crossclamping is associated with a significant release of the myocardial injury marker troponin-T. This seems to correlate with the severity of oxidative rather than hemodynamic stresses. Ameliorating oxidative injury during TAAA surgery may therefore have a cardioprotective effect.