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Notes: Abstract  Endovascular repair of thoracic aortic aneurysms is a promising modality that may someday replace open surgical repair. While stent grafts have been used with moderate success in small to moderate-sized retrospective series, there have been no completed multicenter clinical trials directed at gaining approval from the U.S. Food and Drug Administration. The available data suggest that morbidity and mortality of the procedure may be lowered with endovascular techniques. Paraplegia occurs, but despite the inability to maintain perfusion of intercostal vessels, the rate is at least as low as that associated with open repair. Similar to the minimally invasive repair of infrarenal aneurysms, the trade-off between the open and endovascular approach rests in the necessity to follow patients closely with after endovascular repair. The long-term durability of available devices is unproved, and serial imaging studies must be followed in order to detect device failure prior to the development of devastating clinical sequelae.

Notes: [Auszug] Distant thromboembolic events, such as deep venous thrombosis, myocardial infarction and stroke caused by blood clots, comprise some of the most frequent complications that occur following major operative procedures, traumatic injury and malignancy. In this issue, Murciano et al. ...

Notes: Abstract Thrombolytic therapy is frequently used for the treatment of peripheral arterial occlusion, but clinical predictors of success have not yet been defined. We prospectively evaluated 80 consecutive patients receiving intra-arterial urokinase for acute (〈 14 days) ischemia. Fifty-five patients (69%) were treated for bypass graft occlusion and 25 patients (31%) for native arterial occlusion. Two primary outcome measures were evaluated using multivariate techniques (stepwise logistic regression) to determine the independent predictors of immediate arteriographic success: successful (〉80%) thrombolysis and avoidance of adjuvant operative or endovascular procedures. Independent variables examined included age, sex, comorbid conditions, severity, duration, etiology and location of the ischemic process, and positioning of the infusion catheter and guidewire. Overall, successful lysis was achieved in 57 patients (71%) and adjuvant procedures were avoided in 22 patients (28%). Successful outcome was more frequent in prosthetic graft (78%) and native arterial (72%) occlusions than in vein graft occlusions (53%,p =0.017) and in nondiabetics than in diabetics (80% vs. 52%,p =0.031). Lysis was dependent on placement of the catheter into the substance of the thrombus (85% vs. 0% success,p=0.004) and passage of a guidewire through the occlusive process (92% vs. 10% success,p=0.001). The only parameter independently predictive of successful outcome without the use of adjuvant procedures was the location of the occlusion; additional procedures were necessary in 88% of aortoiliac and 82% of infrainguinal occlusions vs. only 17% of upper extremity occlusions (p=0.005). Thus specific parameters can be identified that predict those patients in whom success, as determined by arteriographic criteria, is most likely to be achieved. Appropriate patient selection is important since unsuccessful thrombolysis protracts the ischemic process and increases the risk of bleeding complications.

Notes: Abstract There exists clinical evidence for a difference in the relative thrombogenicity of arterial and venous surfaces. We studied this phenomenon in an in vitro model where the effects of hemodynamic differences could be controlled. Nonanticoagulated human blood was perfused across injured (air-insufflated) arterial and venous surfaces in a recirculating perfusion system at shear rates of 500 and 1500/sec. Thrombus formation was assessed by measuring radiolabeled platelet (111 In) and fibrin (125I)deposition on the surfaces. The role of von Willebrand factor (vWF) in arterial and venous thrombosis was evaluated by blocking its effect with polyclonal anti-vWF antibody (vWF Ab). Raw data were converted to log 10 for statistical analysis. The increased thrombogenicity of injured venous vs. arterial segments was confirmed by these studies (p〈0.001).The addition of vWF Ab decreased platelet and fibrin deposition (p〈0.001)and these effects were greater in veins than in arteries. The difference in platelet deposition between arteries and veins was more pronounced at lower shear rates (p〈0.05),an effect not observed with fibrin deposition. To determine whether the increased thrombogenicity of veins could be explained by an increased content of subendothelial vWF, the amount of vWF was assessed by incubating injured vessels with 125 I vWF Ab and then measuring the radioactivity of the vessels. Veins had a higher content of vWF than arteries, as implied by the higher amount of radiolabeled vWF Ab (813±90 in veins vs. 2173±317 in arteries,p〈0.001).These observations suggest that increased thrombogenicity of veins may in part be explained by intrinsic differences in subendothelial vWF and subsequent platelet attachment.

Notes: Abstract The presence of horseshoe kidney in conjunction with abdominal aortic disease significantly increases the technical difficulty of aortic reconstruction. Preservation of the renal blood supply and collecting system during the surgical procedure is the goal of operative management. The pertinent issues that remain unresolved include the need for specific preoperative studies, the optimal operative approach and the safety of isthmus division. From 1979 to 1994 eight patients with horseshoe kidney underwent operative intervention for aortic disease. Five men and three women who had a mean age of 66 years underwent seven reconstructions for aneurysmal disease and one for aortoiliac occlusive disease. All operations were elective and the transperitoneal approach was used in all cases. In the patients with aneurysmal disease the mean maximal aortic diameter was 7.3 cm. The mean preoperative serum creatinine value was 1.1 mg/dl. Preoperative identification of horseshoe kidney was accomplished in all seven patients with aneurysmal disease but not in the patient with occlusive disease. The anomaly was correctly identified by CT scan in seven of seven (100%) patients, arteriography in two of eight (25%) patients, ultrasonography in two of seven (29%) patients, and renal scan in one patient. In the three patients who underwent intravenous pyelography (IVP) the caliceal system was demonstrated to be completely separate from the isthmus. Renal artery anomalies were present in six (75%) patients; in three (50%) these anomalies could be not visualized on the preoperative arteriogram. Renal revascularization was accomplished by a variety of techniques, including reimplantation of multiple (one patient) and single (four patients) renal arteries and branch grafting to an individual renal artery (one patient). Isthmus division was required in three patients. Seven patients had no postoperative elevation in the serum creatinine level including the three patients in whom the isthmus was divided. One patient had postoperative renal failure requiring permanent hemodialysis; this patient had massive intraoperative blood loss due to technical difficulties unrelated to the horseshoe kidney. There were no perioperative deaths. Preoperative identification of horseshoe kidney is best accomplished by CT scanning. Arteriography and IVP should be performed routinely to evaluate the arterial and caliceal anatomy. Arteriography frequently fails to identify anomalous circulation; the transperitoneal approach affords the best opportunity to identify these anomalies intraoperatively. Preoperative IVP allows identification of the renal collecting system, facilitating safe division of the isthmus if necessary.

Notes: Abstract Sixty-two bypass grafts to the peroneal artery were performed at the University of Rochester Medical Center between 1984 and 1990. An autogenous conduit was used in 45 patients and a prosthetic conduit in 17 patients. Primary cumulative patiency rates were 49% at two years and 30% at four years following operation. Limb salvage was achieved in 68% of patients. The two year cumulative patency rate was significantly better when the peroneal artery was of good quality arteriographically compared with those in which stenoses were present (75% versus 25%, p〈0.05); in patients without inflow disease compared with patients with inflow disease (56% versus 11%, p〈0.05); and in saphenous vein grafts compared with prosthetic grafts (55% versus 17%, p〈0.05). The factors that did not influence patency were the presence of a direct peroneal collateral vessel filling a pedal vessel, age, sex, diabetes, and the size of the peroneal artery. The results of peroneal artery bypass in end-stage patients are dependent on the presence of adequate autogenous vein and a recipient peroneal vessel free of disease. Under these circumstances, the results of the procedure approach that of standard femorotibial reconstruction.

Notes: Abstract A total of 1572 carotid endarterectomies were performed at one institution between 1975 and 1987. One hundred five patients had early (〈3 weeks) neurologic events following carotid endarterectomy. Sixty-five patients had cerebral vascular accidents (CVAs) (4.1%), 14 patients had reversible ischemic neurologic deficits (0.9%), and 26 patients had transient ischemic attacks (1.7%). Eight patients died from CVAs (0.5%). The mean follow-up was 31 months (range 1 to 137 months) with a 5-year cumulative survival of 77%. The median time of occurrence of neurologic events was 4 hours. Ages, cerebral protection, patches, carotid occlusion time (mean 29 minutes), gender, and status of the contralateral carotid arteries were not predictors of outcome. Death from neurologic events increased significantly in patients who had preoperative CVAs compared with patients with preoperative transient neurologic deficits (p〈0.05). The time of occurrence of CVA after carotid endarterectomy affected outcome, and an early CVA (〈4 hours) was associated with a higher mortality at 30 days and at 4 months as a consequence of the initial CVA (p=0.11). Patients who had a neurologic event more than 4 hours after surgery had a significantly better resolution of their symptoms (66%) compared with patients who had an early neurologic event (35%,p〈0.05). The long-term follow-up of the surviving patients demonstrated an improvement in neurologic function in 75% of the CVA group (36/48) and 92% (76/83) of all patients who had neurologic events in long-term follow-up.