Safety, feasibility, and early efficacy of subfascial endoscopic perforator surgery: a preliminary report from the North American registry.

PURPOSE: The North American Subfascial Endoscopic Perforator Surgery (NASEPS) Registry was established to evaluate the safety, feasibility, and efficacy of minimally invasive endoscopic Linton operations for treatment of chronic venous insufficiency. METHODS: Retrospective analysis was performed on the clinical data of 151 patients who underwent attempt at 158 SEPS in 17 medical centers in the United States and Canada between June 1993 and February 1996. RESULTS: SEPS was completed on 155 limbs of 148 patients, 81 male and 67 female (mean age, 56 years; range, 27 to 87 years). Three procedures were aborted. Seven patients had bilateral procedures (data from one limb were analyzed). One hundred four limbs (70%) had active ulcers, and 22 (15%) had healed ulcers. A single endoscopic port without insufflation was used in 66 procedures (45%) and laparoscopic instrumentation, with two or three ports, in 82 (55%), with CO2 insufflation in 78 (53%). A tourniquet was used on 112 patients (76%). Concomitant venous procedures were performed in 106 patients (72%; saphenous stripping in 71, high ligation in 17, varicosity avulsion in 85). No early deaths or thromboembolism occurred. Complications included wound infections (9), superficial thrombophlebitis (5), cellulitis (4), and saphenous neuralgia (10). Seven patients with wound infection had open ulcers; nine of 10 with neuralgia had concomitant procedures. A roll-on tourniquet caused skin necrosis in one patient. The clinical score improved from 9.4 to 2.9 after surgery (p < 0.0001). Mean follow-up was 5.4 months; 31 patients had > or = 6 months follow-up. Ulcers healed in 88% (75 of 85); recurrence or new ulcer was reported in 3% (4 of 120). CONCLUSIONS: The SEPS modified Linton operation appears safe, with no postoperative deaths or early thromboembolism. Wound infection after SEPS remains important. Early results indicate rapid ulcer healing. Prospective evaluation of long-term results is warranted.

Complementary distal arterio-venous fistula combined with deep vein interposition to improve infrapopliteal prosthetic bypass patency.

The rapid evolution of vascular surgical techniques over the last few years coupled with the availability of an adequate venous conduit has allowed a more liberal and successful approach to salvage ischemic limbs caused by advanced atherosclerosis. This aggressive approach can be exemplified by the construction of arterial bypasses to the terminal branches of tibial vessels. However, a significant number of patients will continue to face the threat of a major amputation because of insufficient amounts of vein(s) to perform a totally autogenous bypass to one of the infrapopliteal arteries.

[Acute embolic stroke treated with rt-PA during elective coronary angiography]. / Acidente vascular cerebral isquêmico agudo embólico tratado com rt-PA durante cinecoronariografia eletiva.

A 56-year-old female with unstable angina, presented an acute embolic ischaemic stroke of right medium cerebral artery during elective coronary angiography. Complete patency was achieved after an intraarterial infusion of rt-PA (60mg/60min) with important functional improvement.

Complementary distal arteriovenous fistula and deep vein interposition: a five-year experience with a new technique to improve infrapopliteal prosthetic bypass patency.

PURPOSE: In an attempt to improve graft patency results of prosthetic bypasses to infrapopliteal arteries, we used a new type of adjunctive technique that combines an arteriovenous fistula and vein interposition (AVF/VI). METHODS: Over the past 5 years, 68 such reconstructions were performed in 62 patients with critical ischemia in whom a totally autogenous vein bypass was not feasible. Forty-seven patients (76%) had one or more failed ipsilateral infrainguinal bypasses. The AVF/VI was performed by transposing the central portion of the adjacent deep vein onto the side of the recipient artery. The distal end of a 6-mm polytetrafluoroethylene (PTFE) ringed graft then was anastomosed to the hood of the AVF. The segment of vein interposed between the PTFE graft and the recipient artery widened the anastomosis and improved the compliance mismatch. Simultaneous pressure measurements of the radial artery and the distal portion of the graft were obtained in all cases. RESULTS: Significant pressure gradients ranging from 35 to 70 mm Hg were detected in 26 bypasses (38%), which led to banding of the venous outflow that decreased the gradient to within 20 mm Hg. A gradient < or = 30 mm Hg was found in 28 bypasses (41%), and no banding was required if the absolute intragraft systolic pressure was > or = 100 mm Hg. Only 14 bypasses (21%) had no detectable pressure gradients. Twenty-six bypasses originated from femoral arteries, 34 from iliac arteries, and 8 from patent proximal grafts. The recipient arteries were the anterior tibial artery in 33 cases, posterior tibial in 17, peroneal in 15, dorsalis pedis in 2, and lateral plantar in 1. All patients began a regimen of heparin 6 to 8 hours after surgery and continued to receive chronic anticoagulation. Cumulative, 3-year assisted primary graft patency rates were 78%, 70%, and 62%, respectively. Cumulative 3-year AVF patency rates were 65%, 57%, and 46%, respectively. The 3-year limb salvage rate was approximately 78%. CONCLUSION: Adjunctive AVF/VI significantly improves infrapopliteal PTFE graft patency and limb salvage rates. The combination of a decreased compliance mismatch at the distal anastomosis and the abolishment of a large pressure gradient at the distal anastomosis while maintaining higher graft flow rates may have contributed to the improved results.

Perfluorocarbon emulsion prevents eicoasanoid release in skeletal muscle ischemia and reperfusion.

Eicosanoids play an important role in mediating deleterious effects following skeletal muscle ischemia-reperfusion injury. It has previously been shown that oxygenated perfluorocarbon emulsion (O2 Fluosol-DA 20%) decreases the amount of muscle necrosis and neutrophil sequestration when given during the reperfusion phase following skeletal muscle ischemia. As thromboxane is known to alter the endothelial cytoskeleton, thereby favoring diapedesis of neutrophils, the effects of O2 Fluosol-DA 20% on thromboxane release in a canine gracilis muscle model were investigated. The gracilis muscle on one randomly selected side of 14 adult mongrel dogs (body-weight 22-26 kg) was subjected to 6 h of normothermic ischemia followed by 48 h of normothermic reperfusion. The control group (n = 7) underwent ischemia-reperfusion, but without any pharmacological intervention. The Fluosol group (n = 7) were infused with O2 Fluosol-DA 20% (4.3(0.2) ml O2/100 ml) at 12 ml/min for 40 min via the gracilis artery following the ischemic period. Thromboxane B2 levels were measured from blood samples obtained at pre-ischemia, and at 1 h and 48 h of reperfusion. The gracilis muscles were harvested at the end of the experiment and extent of muscle necrosis quantitated by serial transections, nitroblue tetrazolium staining and computed planimetry. The mean(s.e.m.) muscle necrosis in the control group (59(6)%) was significantly higher than in the Fluosol group (22(5)%, P < 0.05, t-test). Thromboxane levels (pg/ml) in the control group at 1 h of reperfusion were significantly higher than the pre-ischemic and 48-h reperfusion levels (7286(1383) versus 1336(592) and 2314(1297), P < 0.05 by ANOVA and Student-Newman-Keuls test). The thromboxane level in the Fluosol group at 1 h reperfusion was significantly lower than the control group (2700(556) and 7286(1383) pg/ml, respectively; P < 0.05, t-test). In contrast, there was no statistically significant difference between thromboxane levels in the Fluosol group at 1 h reperfusion compared with levels at pre-ischemia and 48 h reperfusion (2700(556) versus 1336(592) and 1400(474). Thus, perfluorocarbons are effective in decreasing skeletal muscle necrosis, probably by maintaining the endothelial integrity and preventing vasospasm, secondary to their inhibitory effect on thromboxane release. Perfluorocarbons may also minimize some of the deleterious pulmonary effects known to be caused by increased levels of eicosanoids during reperfusion.

The natural history of the external carotid artery after carotid endarterectomy: implications for management.

PURPOSE: Most surgeons perform some type of endarterectomy of the external carotid artery (ECA) routinely during standard carotid endarterectomy (CEA). This approach has been shown to result in a small percentage of ECA occlusions, the clinical significance of which remains poorly understood. We have modified our approach to the management of the ECA during standard CEA by averting any attempt at external CEA. To evaluate the natural history of the untreated ECA after CEA, we reviewed the preoperative, postoperative, and follow-up duplex scans obtained from 232 CEAs over the past 4 years. METHODS: Preoperative and postoperative carotid artery duplex examinations with specific evaluation of the extent of ECA stenosis were available for review on 114 CEAs performed between January 1991 and July 1994. All CEAs were performed for internal carotid artery stenosis greater than 75% as determined by duplex scanning, which was confirmed by either contrast arteriography or magnetic resonance angiography. RESULTS: Seventy-three (64.0%) procedures were performed for symptomatic lesions, whereas 41 (36.0%) were performed for asymptomatic stenosis. There were no perioperative strokes or transient ischemic attacks in this group, and there was one postoperative death (0.9%). Short- and intermediate-term follow-up demonstrated insignificant changes in ECA diameter after operation, with no cases of ECA occlusion and only five cases progressing to greater than 75% on the 1-year follow up duplex examination. CONCLUSION: We conclude from these data that averting external CEA during standard CEA does not result in significant progression of ECA stenosis or occlusion.

Superior vena caval Greenfield filters: indications, techniques, and results.

PURPOSE: This study assessed the clinical feasibility of placement of the titanium Greenfield filter within the superior vena cava (SVC) in patients with upper extremity deep venous thrombosis and evaluated the short-term results. METHODS: During the past 14 months, we have encountered 6 patients who had upper extremity central venous thrombosis in whom anticoagulation was deemed either contraindicated or ineffective in preventing recurrent pulmonary embolism. All patients underwent percutaneous insertion of a Greenfield filter into the SVC for prophylaxis for pulmonary embolism. Two of these patients had already undergone insertion of an inferior vena cava filter and two other patients had simultaneous insertion of SVC and inferior vena caval filters. RESULTS: No complications such as filter migration, misplacement, excessive hemorrhage, or pneumothorax occurred. Two patients subsequently underwent uncomplicated insertion of a Swan-Ganz catheter despite the presence of the filter. Two patients died of unrelated causes without clinical evidence of complications related to the filter. During the follow-up period from 4 to 14 months, there was no clinical evidence of pulmonary embolism in the remaining four patients. CONCLUSIONS: This procedure can be performed safely and is effective for the prevention of pulmonary embolism in patients with upper extremity venous thrombosis.

Preliminary results of a nonoperative approach to saphenofemoral junction thrombophlebitis.

PURPOSE: A prospective, nonrandomized study was conducted to evaluate the efficacy of a nonoperative approach of anticoagulation therapy to manage saphenofemoral junction thrombophlebitis (SFJT). METHODS: Over a 2-year period between January 1993 and January 1995, 20 consecutive patients with SFJT were entered into the study. They were hospitalized and given a full course of heparin. Duplex ultrasonography was performed before admission, both to establish the diagnosis and to evaluate the deep venous system. Two to 4 days after admission a follow-up scan was obtained to assess resolution of SFJT and to reexamine the deep venous system. Patients with SFJT alone and resolution of SFJT by duplex scanning were maintained on warfarin (Coumadin) for 6 weeks. Those with SFJT and deep venous thrombosis (DVT) were maintained on Coumadin for 6 months. Incidence of concurrent DVT and its location were noted. The efficacy of anticoagulation therapy was evaluated by measuring SFJT resolution, recurrent episodes of SFJT, and occurrence of pulmonary embolism (PE). RESULTS: There was a 40% incidence (eight of 20 patients) of concurrent DVT with SFJT. Of the eight patients, four had unilateral DVT, two had bilateral DVT, and two had development of DVT with anticoagulation. DVT was contiguous with SFJT in five patients and noncontiguous in three patients. Of 13 duplex scans obtained at 2 to 8 months follow-up, seven demonstrated partial resolution of SFJT, five had complete resolution, and one did not demonstrate resolution. There were no episodes of PE, no recurrences, and no complications of anticoagulation at maximum follow-up of 14 months. CONCLUSIONS: Anticoagulation therapy to manage SFJT was effective in achieving resolution, preventing recurrence and preventing PE within our follow-up period. There is a high incidence of DVT associated with SFJT that merits careful evaluation of the deep venous system during the course of management.

Noninvasive predictors of patency for infrapopliteal PTFE bypasses with combined arteriovenous fistula and vein interposition technique.

BACKGROUND: Despite recent increased indications for infrapopliteal prosthetic bypass grafts with complementary arteriovenous fistulas, objective documentation of improved perfusion to the foot is lacking. In addition, the value of post operative noninvasive testing in the prediction of bypass success remains unclear. PATIENTS AND METHODS: Over a 3-year period, 41 patients with limb-threatening ischemia were treated with 41 infrapopliteal 6-mm polytetrafluoroethylene (PTFE) bypasses with a complementary arteriovenous fistula at our institution. Twenty-four patients were men and 17 were women, with an average age 71.3 +/- 8.6 years. Thirty-one patients (76%) had undergone at least 1 previous failed ipsilateral arterial bypass. Preoperative and early postoperative (less than 1 month) pulse-volume recordings of transmetatarsal amplitude (TMA) were available for analysis in 28 patients. Postoperative duplex evaluations of graft velocity, fistula patency, and prograde distal arterial flow were performed in 26 of the original 41 patients. These data were correlated to early graft failure in an attempt to identify specific noninvasive predictors. RESULTS: Cumulative primary patency rates of the original 41 patients were 79.0%, 69.2%, and 63.8% at 1, 2, and 3 years, respectively. The early postoperative TMA values ranged from 3 to 50 mm with a mean of 21.6 +/- 14.8 mm (P < 0.001). Twenty-one patients (75%) had patent grafts on follow-up of 2 to 37 months (mean 18.6). The early postoperative TMA in this group of patients was 26.5 +/- 12.4 mm compared with 3.3 +/- 2.8 mm in the 6 patients whose grafts failed within 6 months (P < 0.001). A TMA of < 5 mm was 83% sensitive and 95% specific for the prediction of early graft failure. Of the graft examined by duplex ultrasonography, 21 (81%) remained patent during the follow-up period. The midgraft peak systolic velocity (PSV) of these grafts was 109 +/- 8.0 cm/s compared with 74.2 +/- 15.3 cm/s for the 5 initially patent bypasses that subsequently failed at any time during the follow-up period (P < 0.05). PSV of < 70 cm/s was 60% sensitive and 86% specific in predicting early graft failure. The combination of early postoperative TMA < 5 mm and early midgraft PSV < 70 cm/s was 100% sensitive and 100% specific for the prediction of early graft failure. CONCLUSIONS: These data show that infrapopliteal PTFE arterial bypasses with complementary arteriovenous fistulas significantly improve arterial perfusion at the level of the foot in the majority of patients. Also, both the postoperative TMA and midgraft PSV appear to be reliable predictors of graft outcome. Further experience with the noninvasive surveillance of these bypasses may become as rewarding as it is in standard vein bypasses.

The value and limitations of L-arginine infusion on glomerular and tubular function in the ischemic/reperfused kidney.

PURPOSE: The nitric oxide precursor, L-arginine, has been shown to have a salutary effect on ischemia and reperfusion injury in skeletal muscle, skin, and intestines. Because L-arginine also increases renal blood flow, glomerular filtration, and urine flow in experimental animals with normal renal function, we postulated that L-arginine may also improve renal function after renal ischemic injury. METHODS: Eighteen adult New Zealand white rabbits weighing 3 to 3.5 kg were subjected to bilateral normothermic renal ischemia by clamping both renal pedicles for 1 hour followed by 2 hours of reperfusion. The animals were randomized into three groups: group I (control, n = 6) received no additional treatment; group II (pretreatment, n = 6) received systemic intravenous L-arginine at 150 mg/kg over 20 minutes before induction of ischemia; group III (posttreatment, n = 6) received systemic intravenous L-arginine at 150 mg/kg over 20 minutes from the onset of reperfusion. Urine flow, creatinine clearance (CCR), fractional excretion of sodium (FENa), and renal failure index (RFI) were calculated before ischemia and 2 hours after reperfusion, by use of standard formulas. The changes of the various renal parameters were compared among the three groups. RESULTS: Bilateral normothermic renal ischemia for 1 hour produced a significant deterioration of glomerular filtration as evidenced by a CCR decrease from 11.1 +/- 1.8 to 2.49 +/- 0.9 ml/min (p < 0.01), FENa increase from 2.9% +/- 1.0% to 20.8% +/- 1.5% (p < 0.01) and RFI increase from 4.0 +/- 1.3 to 28.8 +/- 2.6 (p < 0.01). Pretreatment with L-arginine (group II) minimized the deleterious effects caused by ischemia on glomerular filtration (CCR of 2.49 +/- 0.9 ml/min in group I vs 4.95 +/- 2.5 ml/min in group II, p < 0.05) and tubular function (FENa of 20.8% +/- 1.5% in group I vs 13.0% +/- 5.6% in group II and RFI of 28.8 +/- 2.6 in group I vs 18.6 +/- 8.0 in group II, p < 0.05). Infusion of L-arginine at the onset of reperfusion (group III) produced a significant diuretic effect (urine flow from 32.6 +/- 13.4 ml/hr in group I to 63.3 +/- 18.8 ml/hr in group III, p < 0.05) and also minimized glomerular damage (CCR from 2.49 +/- 0.9 ml/min in group I to 4.80 +/- 1.2 ml/min in group III, p < 0.05); however, no beneficial effect was observed on tubular function. CONCLUSION: Induction of nitric oxide production by systemic L-arginine infusion can best preserve glomerular and tubular function in the ischemic/reperfused kidney when given before the ischemic insult.

Outcome of patients with abnormal ocular pneumoplethysmographic measurements undergoing coronary artery bypass grafting.

A total of 1780 patients without symptoms of cerebral ischemia undergoing coronary artery bypass grafting (CABG) were screened before surgery for carotid stenosis by pneumophlethysmography. An abnormal test was defined as a difference in ophthalmic artery pressures of > or = 5 mmHg or ophthalmic-brachial pressure index < or = 0.69. Some 99 patients (5.6%) had an abnormal ocular pneumoplethysmographic measurement (89 unilateral, ten bilateral). Of these, 26 patients underwent prophylactic carotid endarterectomy before CABG (group 1), while the remaining 73 patients had reconstruction without previous carotid endarterectomy (group 2). A total of 100 patients (group 3) with normal ocular pneumoplethysmographic results were used as controls. The three groups were comparable with respect to age, diabetes, hypertension, smoking and severity of coronary artery disease. Early (30-day) postoperative stroke rates were 0 and 4% (n = 3) for groups 1 and 2 respectively, and 0% for group 3 (P > 0.07). Early mortality rates after CABG for groups 1 and 2 were 4% (n = 1) and 1% (n = 1), respectively and 2% (n = 2) for groups 3 (P > 0.4). Late follow-up (mean 48 months) demonstrated stroke rates of 0% for group 1, and 10% and 4% for groups 2 and 3 (P > 0.08). The early mortality and stroke rates in the ten patients with bilateral abnormal ocular pneumoplethysmographic values were 0 and 0%. However, late strokes occurred significantly more often (43%) in patients with bilateral abnormal results compared with those with unilateral abnormal findings when both groups did not undergo carotid endarterectomy (P < 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Unilateral renal artery revascularization can salvage renal function and terminate dialysis in selected patients with uremia.

Revascularization of renal arteries to salvage glomerular function in patients with chronic renal failure is performed infrequently. However, during the past 12 months we have encountered three patients over 60 years of age known to have chronic renal failure who were on dialysis for 2 weeks, 3 weeks, and 2 months, respectively. All three patients were hypertensive, requiring between four and five antihypertensive medications. One patient was ventilator dependent in intractable cardiac failure with pulmonary artery systolic pressures ranging from 60 to 70 mm Hg. Standard biplanar arteriography revealed occlusion of the left renal artery with distal reconstitution in two patients and a 99% stenosis of the right renal artery in the remaining patient. The contralateral renal artery was totally occluded in two patients and diffusely stenotic in one. The recipient kidneys measured 8, 10, and 11 cm in length. Kidney function was assessed by renal scintigraphy and creatinine clearance. Two splenorenal bypasses and one hepatorenal bypass with 6 mm polytetrafluoroethylene graft were performed successfully. After surgery, renal function improved in all patients with two of three patients resuming normal function as evidenced by reduction of serum creatinine levels to 0.9 and 1.3 mg/dl. The third patient recovered to have a creatinine level of 3.2 mg/dl. All patients were discharged home within 1 month with a daily urine output greater than 1500 ml. At discharge, each patient required only two antihypertensive medications to control blood pressure. Duplex scanning 3, 6, and 12 months after surgery confirmed patency of all reconstructions.(ABSTRACT TRUNCATED AT 250 WORDS)

The preferential use of the external iliac artery as an inflow source for redo femoropopliteal and infrapopliteal bypass.

PURPOSE: It is believed that secondary operations involving the inguinal region are associated with a significant morbidity that includes infection, lymphatic obstruction, lymphorrhea, and neurovascular injury. To prevent these potentially important complications we have avoided a redo groin incision in 38 patients with severely symptomatic disease who had primary (23 cases) or secondary (15 cases) femoropopliteal bypass thrombosis during the past 3 years. METHODS: All patients were candidates for prosthetic bypasses because of lack of a suitable vein. Twenty-nine external iliac-to-popliteal bypasses (18 above-knee; 11 below-knee) and nine external iliac-to-infrapopliteal bypasses (five anterior tibial; two posterior tibial; two peroneal) were performed with 6 mm polytetrafluoroethylene ringed grafts in 38 patients. Adjunctive distal arteriovenous fistulas were constructed in all infrapopliteal bypasses. The external iliac artery was exposed via a retroperitoneal approach. The second incision was placed just below the scarred area and deepened to the level of the medial border of the sartorius muscle. A tunnel that connected both incisions was easily created by blunt dissection alongside the anterolateral border of the femoral artery. RESULTS: Four popliteal bypasses occluded at 4, 6, 10, and 28 months after operation. The remaining 25 grafts are patent (mean 14 months). Three of the infrapopliteal bypasses occluded at 0, 2, and 3 months after operation. The remaining six grafts are patent with follow-up from 4 to 18 months (mean 12 months). Only one patient had a superficial wound infection at the below-knee popliteal incision, which healed with local treatment. All other patients had an uneventful postoperative course. CONCLUSIONS: Thus we believe this approach to be simple, safe, and durable and should be used preferentially to avoid the difficult and hazardous dissection of a previously operated groin.

Acute mesenteric ischemia after cardiopulmonary bypass.

Three thousand sixty-six patients underwent cardiopulmonary bypass at the Maimonides Medical Center over a 5-year period from January 1, 1987, to January 1, 1992. Of these patients, 1,890 (62%) were less than 70 years of age, 969 (32%) ranged from 70 to 79 years of age, and 207 (7%) were 80 years of age or older. The overall 30-day mortality rate was 8%. Eleven patients developed acute mesenteric ischemia from 24 hours to 12 days postoperatively. At the time of diagnosis, the majority of patients presented with late classical signs and symptoms of acute mesenteric ischemia including abdominal distension, respiratory distress, hypotension, oliguria, and sepsis. All patients underwent immediate laparotomy. Extensive bowel necrosis was found in all, and resection was possible in eight patients. All patients died as a result of this complication. Using the exact trend test, we found a statistically significant increase in the incidence of deaths due to acute mesenteric ischemia after cardiopulmonary bypass in older compared with younger patients. This fatal complication after cardiopulmonary bypass occurs more often than previously believed and is a relatively common cause of death in the elderly.

The relationship between timing of repair of disruptions and subsequent aneurysm formation in laser-assisted microvascular anastomoses.

In this study we investigated the effects of duration of bleeding after laser-assisted microvascular anastomoses and the amount of laser energy used to control bleeding on aneurysm formation. Eighty femoral arteries were exposed in 40 Sprague-Dawley rats anesthetized with chloral hydrate. The arteries were transected and then anastomosed end-to-end with three nylon stay sutures followed by irradiation of the vessels with energy from a CO2 laser. The laser power was kept at 90 mW, and each of three segments between stay sutures was exposed for 6 seconds to continuous laser energy. If anastomotic disruption (defined as bleeding after completion of the anastomosis) occurred, it was controlled with pressure over the disrupted site for 10, 25, or 40 seconds. Disruptions were required with exposure to additional laser energy for either 6 (group 1) or 12 seconds (group 2). The anastomoses were inspected at 21 days postoperatively to assess patency and aneurysm formation. Twenty-six of 80 vessels (32%) were anastomosed without the occurrence of disruptions: these 26 vessels had a 100 per cent patency rate and did not develop aneurysms. In group 1, the incidence of redisruption following a primary disruption was the same irrespective of duration of bleeding (4/8, 3/6, and 3/6 for 10-, 25-, and 40-seconds bleeding time, respectively P = NS). Similarly, there was no difference in the incidence of aneurysm formation in this group (0/8, 2/6, and 2/6 for 10, 25, and 40", respectively, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Association of intra-abdominal pathologies and vascular anomalies with infrarenal aortic aneurysm: a computed tomographic study.

The prevalence of potentially significant intra-abdominal pathologies or vascular anomalies in candidates for infrarenal aortic aneurysm repair remains unclear. This study retrospectively reviewed 130 consecutive patients with aortic aneurysms (4.5-10.0 cm in largest diameter) who had undergone contrast-enhanced abdominal computed tomography. The overall incidence of potentially significant pathologies was 31.5%. Gallstones were detected in 25 patients (19.2%), adrenal masses in six (4.6%), pancreatic tumors in two (1.5%), renal stones in two (1.5%), liver metastases in one (0.8%), retroperitoneal lymphoma in one (0.8%) and left gastric artery aneurysm in one (0.8%). Other pathologies included renal cysts in 42 patients (32.3%), colonic diverticulosis in nine (6.9%) and hepatic cysts in three (2.3%). Major vascular anomalies were encountered in only three of the 130 patients (2.3%) and these included two with a left-sided inferior vena cava and one case of retroaortic left renal vein. This study emphasizes the high incidence of potentially significant intra-abdominal pathologies and the low incidence of major vascular anomalies associated with infrarenal aortic aneurysm. The impact of such findings on the management of aortic aneurysms is discussed.

Silent myocardial ischemia is not predictive of myocardial infarction in peripheral vascular surgery patients.

Continuous ambulatory ECG (CAECG) monitoring has been advocated as an effective low-cost preoperative method for detecting silent myocardial ischemia in patients undergoing peripheral vascular surgery. In addition, silent ischemic events are associated with an increased incidence of postoperative myocardial infarctions. Ninety-six patients (mean age 73 years) admitted for elective aortic (24) or infrainguinal (72) operations over a 2-year period underwent 24-hour two- or three-lead CAECG monitoring. Results were reviewed by a single cardiologist blinded to the study. The criterion for ischemia was ST segment depressions of 1 mm or greater for 40 seconds or more 60 msec after the J point. Postoperative myocardial infarction was determined by ECG changes and/or elevated serum creatinine phosphokinase with positive MB isoenzymes. Risk factors included hypertension (71%), history of coronary artery disease (66%), smoking (61%), and diabetes mellitus (47%). Nine out of 96 patients (9.4%) had a positive CAECG test for silent myocardial ischemia. Only one patient (11.1%) developed postoperative myocardial infarction and there were no deaths in this group. The incidence of postoperative myocardial infarction in the nonischemic group was 16.1% (14/87). However, the mortality in this group was 6.9% (6/87). New and malignant arrhythmias requiring preoperative medical intervention were observed in seven patients (7.4%): two cases of ventricular tachycardia and five cases of atrial flutter/fibrillation. Contrary to previous reports, CAECG monitoring for silent ischemia was not a significant predictor of postoperative myocardial infarction or mortality in our patient population. However, we continue to recommend the preoperative use of CAECG monitoring as a diagnostic tool for unsuspected malignant arrhythmias.

Intrathecal perfusion of an oxygenated perfluorocarbon prevents paraplegia after aortic occlusion.

A canine model was used to evaluate the effects of continuous intrathecal perfusion of an oxygenated perfluorocarbon emulsion on systemic and cerebral hemodynamics and neurologic outcome after 70 minutes of normothermic aortic occlusion. Twelve mongrel dogs were instrumented to monitor proximal and distal arterial blood pressure, cerebrospinal fluid pressure, spinal cord perfusion pressure, and somatosensory evoked potentials. The intrathecal perfusion apparatus consisted of two perfusing catheters, placed in the intrathecal space through a laminectomy, and a draining catheter percutaneously inserted in the cisterna cerebellomedullaris. The aorta was cross-clamped just distal to the left subclavian artery for 70 minutes. Animals were randomized into two groups: group 1 (n = 6) animals were treated with intrathecal perfusion of saline solution, whereas group 2 (n = 6) animals received oxygenated Fluosol-DA 20%. Data were acquired at baseline, during the cross-clamp period, and after reperfusion. Normothermic Fluosol or saline solution was infused at a rate of 15 mL/min beginning 15 minutes before cross-clamping and continued throughout the ischemic interval. There was no difference in proximal arterial blood pressure (97.2 versus 95.4 mm Hg; p > 0.05) or distal arterial blood pressure (14.6 versus 15.0; p > 0.05) between the two groups throughout the cross-clamp interval. Cerebrospinal fluid pressure rose significantly in both groups with the onset of intrathecal perfusion of either saline solution or Fluosol (7 +/- 1 versus 24 +/- 5 and 8 +/- 1 versus 40 +/- 4 mm Hg, respectively; p < 0.05). The rise in cerebrospinal fluid pressure was sustained throughout the perfusion interval in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Do cytokines play a role in skeletal muscle ischemia and reperfusion?

Cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF) are known to mediate host cell response to sepsis, trauma, and myocardial ischemia. We have previously found increased levels of IL-1 in the venous effluent during the reperfusion phase of skeletal muscle ischemia in a canine model. This study was done to evaluate whether TNF also played a role in skeletal muscle ischemia-reperfusion injury since IL-1 and TNF have inter-related functions. In twelve adult mongrel dogs (28-32 kg) one gracilis muscle was subjected to six hours of normothermic ischemia followed by normothermic reperfusion. The contralateral side served as a control and remained normally perfused throughout the experiment. Gracilis venous samples were collected at pre-ischemia and one hour of reperfusion. Systemic (arterial) blood samples were taken simultaneously with the venous samples at one hour of reperfusion. At the end of the experiment the muscles were harvested and amount of necrosis quantitated by serial transections, nitroblue tetrazolium staining and computerized planimetry. Muscle necrosis on the experimental side was found to be 48.86 +/- 5.37%. Sera were analyzed for TNF activity using a bioassay. TNF levels in the gracilis venous effluent at one hour of reperfusion were not significantly different from the simultaneous systemic (arterial) levels (27.15 +/- 5.05 pg/ml vs 18.23 +/- 4.27 pg/ml). Pre-ischemic levels of TNF were 96.50 +/- 20.12 pg/ml, which was significantly higher than either venous or arterial levels obtained after one hour of reperfusion (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)