Recommended standards for reports dealing with lower extremity ischemia: revised version

Recommended standards for analyzing and reporting on lower extremity ischemia were first published by the Journal of Vascular Surgery in 1986 after approval by the Joint Council of The Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery. Many of these standards have been accepted and are used in the current literature on peripheral arterial occlusive disease. With the passage of time, some oversights, aspects that require clarification, and better modifications have been recognized. This report attempts to correct these shortcomings while reinforcing those recommendations that have proven satisfactory. Explanatory comments are added to facilitate understanding and application. This version is intended to replace the original version.

Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicentre, randomised controlled trial

BACKGROUND

The treatment of rest pain, ulceration, and gangrene of the leg (severe limb ischaemia) remains controversial. We instigated the BASIL trial to compare the outcome of bypass surgery and balloon angioplasty in such patients.

METHODS

We randomly assigned 452 patients, who presented to 27 UK hospitals with severe limb ischaemia due to infra-inguinal disease, to receive a surgery-first (n=228) or an angioplasty-first (n=224) strategy. The primary endpoint was amputation (of trial leg) free survival. Analysis was by intention to treat. The BASIL trial is registered with the National Research Register (NRR) and as an International Standard Randomised Controlled Trial, number ISRCTN45398889.

FINDINGS

The trial ran for 5.5 years, and follow-up finished when patients reached an endpoint (amputation of trial leg above the ankle or death). Seven individuals were lost to follow-up after randomisation (three assigned angioplasty, two surgery); of these, three were lost (one angioplasty, two surgery) during the first year of follow-up. 195 (86%) of 228 patients assigned to bypass surgery and 216 (96%) of 224 to balloon angioplasty underwent an attempt at their allocated intervention at a median (IQR) of 6 (3-16) and 6 (2-20) days after randomisation, respectively. At the end of follow-up, 248 (55%) patients were alive without amputation (of trial leg), 38 (8%) alive with amputation, 36 (8%) dead after amputation, and 130 (29%) dead without amputation. After 6 months, the two strategies did not differ significantly in amputation-free survival (48 vs 60 patients; unadjusted hazard ratio 1.07, 95% CI 0.72-1.6; adjusted hazard ratio 0.73, 0.49-1.07). We saw no difference in health-related quality of life between the two strategies, but for the first year the hospital costs associated with a surgery-first strategy were about one third higher than those with an angioplasty-first strategy.

INTERPRETATION

In patients presenting with severe limb ischaemia due to infra-inguinal disease and who are suitable for surgery and angioplasty, a bypass-surgery-first and a balloon-angioplasty-first strategy are associated with broadly similar outcomes in terms of amputation-free survival, and in the short-term, surgery is more expensive than angioplasty.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA

BACKGROUND

Combination antiplatelet therapy with clopidogrel and aspirin may reduce the rate of recurrent stroke during the first 3 months after a minor ischemic stroke or transient ischemic attack (TIA). A trial of combination antiplatelet therapy in a Chinese population has shown a reduction in the risk of recurrent stroke. We tested this combination in an international population.

METHODS

In a randomized trial, we assigned patients with minor ischemic stroke or high-risk TIA to receive either clopidogrel at a loading dose of 600 mg on day 1, followed by 75 mg per day, plus aspirin (at a dose of 50 to 325 mg per day) or the same range of doses of aspirin alone. The dose of aspirin in each group was selected by the site investigator. The primary efficacy outcome in a time-to-event analysis was the risk of a composite of major ischemic events, which was defined as ischemic stroke, myocardial infarction, or death from an ischemic vascular event, at 90 days.

RESULTS

A total of 4881 patients were enrolled at 269 international sites. The trial was halted after 84% of the anticipated number of patients had been enrolled because the data and safety monitoring board had determined that the combination of clopidogrel and aspirin was associated with both a lower risk of major ischemic events and a higher risk of major hemorrhage than aspirin alone at 90 days. Major ischemic events occurred in 121 of 2432 patients (5.0%) receiving clopidogrel plus aspirin and in 160 of 2449 patients (6.5%) receiving aspirin plus placebo (hazard ratio, 0.75; 95% confidence interval [CI], 0.59 to 0.95; P=0.02), with most events occurring during the first week after the initial event. Major hemorrhage occurred in 23 patients (0.9%) receiving clopidogrel plus aspirin and in 10 patients (0.4%) receiving aspirin plus placebo (hazard ratio, 2.32; 95% CI, 1.10 to 4.87; P=0.02).

CONCLUSIONS

In patients with minor ischemic stroke or high-risk TIA, those who received a combination of clopidogrel and aspirin had a lower risk of major ischemic events but a higher risk of major hemorrhage at 90 days than those who received aspirin alone. (Funded by the National Institute of Neurological Disorders and Stroke; POINT ClinicalTrials.gov number, NCT00991029 .).

Aspirin and mortality from coronary bypass surgery

BACKGROUND

There is no therapy known to reduce the risk of complications or death after coronary bypass surgery. Because platelet activation constitutes a pivotal mechanism for injury in patients with atherosclerosis, we assessed whether early treatment with aspirin could improve survival after coronary bypass surgery.

METHODS

At 70 centers in 17 countries, we prospectively studied 5065 patients undergoing coronary bypass surgery, of whom 5022 survived the first 48 hours after surgery. We gathered data on 7500 variables per patient and adjudicated outcomes centrally. The primary focus was to discern the relation between early aspirin use and fatal and nonfatal outcomes.

RESULTS

During hospitalization, 164 patients died (3.2 percent), and 812 others (16.0 percent) had nonfatal cardiac, cerebral, renal, or gastrointestinal ischemic complications. Among patients who received aspirin (up to 650 mg) within 48 hours after revascularization, subsequent mortality was 1.3 percent (40 of 2999 patients), as compared with 4.0 percent among those who did not receive aspirin during this period (81 of 2023, P<0.001). Aspirin therapy was associated with a 48 percent reduction in the incidence of myocardial infarction (2.8 percent vs. 5.4 percent, P<0.001), a 50 percent reduction in the incidence of stroke (1.3 percent vs. 2.6 percent, P=0.01), a 74 percent reduction in the incidence of renal failure (0.9 percent vs. 3.4 percent, P<0.001), and a 62 percent reduction in the incidence of bowel infarction (0.3 percent vs. 0.8 percent, P=0.01). Multivariate analysis showed that no other factor or medication was independently associated with reduced rates of these outcomes and that the risk of hemorrhage, gastritis, infection, or impaired wound healing was not increased with aspirin use (odds ratio for these adverse events, 0.63; 95 percent confidence interval, 0.54 to 0.74).

CONCLUSIONS

Early use of aspirin after coronary bypass surgery is safe and is associated with a reduced risk of death and ischemic complications involving the heart, brain, kidneys, and gastrointestinal tract.

Acute mesenteric ischemia: a clinical review

Acute mesenteric ischemia is a life-threatening vascular emergency that requires early diagnosis and intervention to adequately restore mesenteric blood flow and to prevent bowel necrosis and patient death. The underlying cause is varied, and the prognosis depends on the precise pathologic findings. Despite the progress in understanding the pathogenesis of mesenteric ischemia and the development of modern treatment modalities, acute mesenteric ischemia remains a diagnostic challenge for clinicians, and the delay in diagnosis contributes to the continued high mortality rate. Early diagnosis and prompt effective treatment are essential to improve the clinical outcome.

The AtRial Cardiopathy and Antithrombotic Drugs In prevention After cryptogenic stroke randomized trial: Rationale and methods

RATIONALE

Recent data suggest that a thrombogenic atrial substrate can cause stroke in the absence of atrial fibrillation. Such an atrial cardiopathy may explain some proportion of cryptogenic strokes.

AIMS

The aim of the ARCADIA trial is to test the hypothesis that apixaban is superior to aspirin for the prevention of recurrent stroke in subjects with cryptogenic ischemic stroke and atrial cardiopathy.

SAMPLE SIZE ESTIMATE

1100 participants.

METHODS AND DESIGN

Biomarker-driven, randomized, double-blind, active-control, phase 3 clinical trial conducted at 120 U.S. centers participating in NIH StrokeNet.

POPULATION STUDIED

Patients ≥ 45 years of age with embolic stroke of undetermined source and evidence of atrial cardiopathy, defined as ≥ 1 of the following markers: P-wave terminal force >5000 µV × ms in ECG lead V1, serum NT-proBNP > 250 pg/mL, and left atrial diameter index ≥ 3 cm/m2 on echocardiogram. Exclusion criteria include any atrial fibrillation, a definite indication or contraindication to antiplatelet or anticoagulant therapy, or a clinically significant bleeding diathesis. Intervention: Apixaban 5 mg twice daily versus aspirin 81 mg once daily. Analysis: Survival analysis and the log-rank test will be used to compare treatment groups according to the intention-to-treat principle, including participants who require open-label anticoagulation for newly detected atrial fibrillation.

STUDY OUTCOMES

The primary efficacy outcome is recurrent stroke of any type. The primary safety outcomes are symptomatic intracranial hemorrhage and major hemorrhage other than intracranial hemorrhage.

DISCUSSION

ARCADIA is the first trial to test whether anticoagulant therapy reduces stroke recurrence in patients with atrial cardiopathy but no known atrial fibrillation.

Systematic review of survival after acute mesenteric ischaemia according to disease aetiology

BACKGROUND

Differentiation of acute mesenteric ischaemia on the basis of aetiology is of great importance because of variation in disease progression, response to treatment and outcome. The aim of this study was to analyse the published data on survival following acute mesenteric ischaemia over the past four decades in relation to disease aetiology and mode of treatment.

METHOD

A systematic review of the available literature from 1966 to 2002 was performed.

RESULTS

Quantitative analysis of data derived from 45 observational studies containing 3692 patients with acute mesenteric ischaemia showed that the prognosis after acute mesenteric venous thrombosis is better than that following acute arterial mesenteric ischaemia; the prognosis after mesenteric arterial embolism is better than that after arterial thrombosis or non-occlusive ischaemia; the mortality rate following surgical treatment of arterial embolism and venous thrombosis (54.1 and 32.1 per cent respectively) is less than that after surgery for arterial thrombosis and non-occlusive ischaemia (77.4 and 72.7 per cent respectively); and the overall survival after acute mesenteric ischaemia has improved over the past four decades.

CONCLUSION

There are large differences in prognosis after acute mesenteric ischaemia depending on aetiology. Surgical treatment of arterial embolism has improved outcome whereas the mortality rate following surgery for arterial thrombosis and non-occlusive ischaemia remains poor.

The golden hour and the silver day: detection and correction of occult hypoperfusion within 24 hours improves outcome from major trauma

BACKGROUND

The significance of occult hypoperfusion (OH) in the development of respiratory complications (RC), multiple system organ failure (MSOF), and death, and the effect of rapid identification and correction of OH in the severely injured trauma patient was investigated.

METHODS

A pilot retrospective study and the analysis of a prospective protocol to correct OH were performed. Pilot study: all trauma patients admitted to our Level I trauma center between February and December of 1995, who survived greater than 48 hours, had an Injury Severity Score greater than or equal to 20, and intensive care unit stays greater than 48 hours were evaluated. Prospective study: patients admitted between January 1, 1996, and April 30, 1997, who survived greater than 24 hours, with Injury Severity Score greater than or equal to 20, and who were hemodynamically stable (systolic blood pressure greater than 100, pulse rate less than 120, and urine output greater than 1 mL/kg per hour) were included. Serum lactic acid (LA) levels were measured at arrival and at proscribed intervals. In the pilot study, initial LA levels were examined in relation to outcome and complications. In the prospective study, patients with two consecutive LA levels greater than 2.5 mmol/L underwent invasive monitoring and vigorous resuscitation to correct their lactic acidosis.

RESULTS

Among the 31 patients studied in the pilot study, there were 4 deaths, 6 cases of MSOF, and 13 patients with RC. Lactic acidosis and poor cardiac performance, as evidenced by low cardiac index (CI) with normal filling pressures, were seen in all cases of MSOF and RC, as well as in all deaths. From these results, the prospective study was performed. Eighty-five intensive care unit patients met criteria for inclusion in the study. Six additional patients were excluded because of severe, untreatable intracranial hypertension at admission to the intensive care unit. Fifty-eight of these patients had OH in the first 24 hours. Forty-four patients corrected their OH within 24 hours with vigorous resuscitation. There were no deaths, three cases of MSOF, and 10 cases of RC in those patients who corrected OH within 24 hours. Persistent OH (>24 hours) was seen in 14 patients, despite resuscitative efforts, 43% of whom died. MSOF and RC were present in 36% and 50% of cases, respectively (p<0.05).

CONCLUSION

Initial lactic acidosis is associated with lower cardiac performance and higher morbidity and mortality. Persistent OH is associated with higher rates of RC, MSOF, and death after severe trauma. Early identification and aggressive resuscitation aimed at correcting continued elevation in serum lactate improves survival and reduces complications in severely injured trauma patients.

Endothelial cell and hepatocyte deaths occur by apoptosis after ischemia-reperfusion injury in the rat liver

BACKGROUND

Ischemic injury of the liver is generally considered to result in necrosis, but it has recently been recognized that mediators of apoptosis are activated during ischemia/reperfusion. This study was designed to characterize the extent and the type of cells within the liver that undergo apoptosis at different periods of ischemia and reperfusion.

METHODS

Male Wistar rats were subjected to 30 or 60 min of normothermic ischemia. Liver sections were evaluated at the end of ischemia and at 1, 6, 24, and 72 hr after reperfusion. Apoptosis was determined by DNA fragmentation as evaluated by laddering on gel electrophoresis, in situ staining for apoptotic cells using TdT-mediated dUTP-digoxigenin nick-end labeling (TUNEL), and morphology on electron microscopy.

RESULTS

In situ staining of liver biopsy specimens using TUNEL showed significant apoptosis after reperfusion. Sinusoidal endothelial cells (SEC) showed evidence of apoptosis earlier than hepatocytes. For example, at 1 hr of reperfusion after 60 min of ischemia, 22+/-4% of the SEC stained TUNEL positive compared with 2+/-1% of the hepatocytes (P<0.001). With a longer duration of ischemia, a greater number of SEC and hepatocytes became TUNEL positive. An increase in TUNEL-positive cells was also noted with an increasing duration of reperfusion. The presence of apoptotic SEC and hepatocytes was supported by DNA laddering on gel electrophoresis and cell morphology on electron microscopy. Several Kupffer cells were seen containing apoptotic bodies but did not show evidence of apoptosis. Only rare hepatocytes showed features of necrosis after 60 min of ischemia and 6 hr of reperfusion.

CONCLUSION

These results suggest that apoptosis of endothelial cells followed by hepatocytes is an important mechanism of cell death after ischemia/reperfusion injury in the liver.

Contemporary management of acute mesenteric ischemia: Factors associated with survival

PURPOSE

Acute mesenteric ischemia (AMI) is a morbid condition with a difficult diagnosis and a high rate of complications, which is associated with a high mortality rate. For the evaluation of the results of current management and the examination of factors associated with survival, we reviewed our experience.

METHODS

The clinical data of all the patients who underwent operation for AMI between January 1, 1990, and December 31, 1999, were retrospectively reviewed, clinical outcome was recorded, and factors associated with survival rate were analyzed.

RESULTS

Fifty-eight patients (22 men and 36 women; mean age, 67 years; age range, 35 to 96 years) underwent study. The cause of AMI was embolism in 16 patients (28%), thrombosis in 37 patients (64%), and nonocclusive mesenteric ischemia (NMI) in five patients (8.6%). Abdominal pain was the most frequent presenting symptom (95%). Twenty-five patients (43%) had previous symptoms of chronic mesenteric ischemia. All the patients underwent abdominal exploration, preceded with arteriography in 47 (81%) and with endovascular treatment in eight. Open mesenteric revascularization was performed in 43 patients (bypass grafting, n = 22; thromboembolectomy, n = 19; patch angioplasty, n = 11; endarterectomy, n = 5; reimplantation, n = 2). Thirty-one patients (53%) needed bowel resection at the first operation. Twenty-three patients underwent second-look procedures, 11 patients underwent bowel resections (repeat resection, n = 9), and three patients underwent exploration only. The 30-day mortality rate was 32%. The rate was 31% in patients with embolism, 32% in patients with thrombosis, and 80% in patients with NMI. Multiorgan failure (n = 18 patients) was the most frequent cause of death. The cumulative survival rates at 90 days, at 1 year, and at 3 years were 59%, 43%, and 32%, respectively, which was lower than the rate of a Midwestern white control population (P <.001). Six of the 16 late deaths (38%) occurred because of complications of mesenteric ischemia. Age less than 60 years (P <.003) and bowel resection (P =.03) were associated with improved survival rates.

CONCLUSION

The contemporary management of AMI with revascularization with open surgical techniques, resection of nonviable bowel, and liberal use of second-look procedures results in the early survival of two thirds of the patients with embolism and thrombosis. Older patients, those who did not undergo bowel resection, and those with NMI have the highest mortality rates. The long-term survival rate remains dismal. Timely revascularization in patients who are symptomatic with chronic mesenteric ischemia should be considered to decrease the high mortality rate of AMI.

Peripheral Angioplasty as the First-choice Revascularization Procedure in Diabetic Patients with Critical Limb Ischemia: Prospective Study of 993 Consecutive Patients Hospitalized and Followed Between 1999 and 2003

OBJECTIVE

To evaluate the effectiveness of peripheral angioplasty (PTA) as the first-choice revascularisation procedure in diabetic patients with critical limb ischemia (CLI).

DESIGN

Prospective study.

METHODS

PTA was employed as first choice revascularisation in a consecutive series of diabetic patients hospitalized for CLI between January 1999 and December 2003.

RESULTS

PTA was successful performed in 993 patients. Seventeen (1.7%) major amputations were carried out. One death and 33 non-fatal complications were observed. Mean follow-up was 26+/-15 months. Clinical restenosis was observed in 87 patients. The 5 years primary patency was 88%, 95% CI 86-91%. During follow-up 119 (12.0%) patients died at a rate of 6.7% per year.

CONCLUSIONS

PTA as the first choice revascularisation procedure is feasible, safe and effective for limb salvage in a high percentage of diabetic patients. Clinical restenosis was an infrequent event and PTA could successfully be repeated in most cases.

Effect of fibroblast growth factor NV1FGF on amputation and death: a randomised placebo-controlled trial of gene therapy in critical limb ischaemia

BACKGROUND

Patients with critical limb ischaemia have a high rate of amputation and mortality. We tested the hypothesis that non-viral 1 fibroblast growth factor (NV1FGF) would improve amputation-free survival.

METHODS

In this phase 3 trial (EFC6145/TAMARIS), 525 patients with critical limb ischaemia unsuitable for revascularisation were enrolled from 171 sites in 30 countries. All had ischaemic ulcer in legs or minor skin gangrene and met haemodynamic criteria (ankle pressure <70 mm Hg or a toe pressure <50 mm Hg, or both, or a transcutaneous oxygen pressure <30 mm Hg on the treated leg). Patients were randomly assigned to either NV1FGF at 0·2 mg/mL or matching placebo (visually identical) in a 1:1 ratio. Randomisation was done with a central interactive voice response system by block size 4 and was stratified by diabetes status and country. Investigators, patients, and study teams were masked to treatment. Patients received eight intramuscular injections of their assigned treatment in the index leg on days 1, 15, 29, and 43. The primary endpoint was time to major amputation or death at 1 year analysed by intention to treat with a log-rank test using a multivariate Cox proportional hazard model. This trial is registered with ClinicalTrials.gov, number NCT00566657.

FINDINGS

259 patients were assigned to NV1FGF and 266 to placebo. All 525 patients were analysed. The mean age was 70 years (range 50-92), 365 (70%) were men, 280 (53%) had diabetes, and 248 (47%) had a history of coronary artery disease. The primary endpoint or components of the primary did not differ between treatment groups, with major amputation or death in 86 patients (33%) in the placebo group, and 96 (36%) in the active group (hazard ratio 1·11, 95% CI 0·83-1·49; p=0·48). No significant safety issues were recorded.

INTERPRETATION

TAMARIS provided no evidence that NV1FGF is effective in reduction of amputation or death in patients with critical limb ischaemia. Thus, this group of patients remains a major therapeutic challenge for the clinician.

FUNDING

Sanofi-Aventis, Paris, France.

A decade of experience with dorsalis pedis artery bypass: analysis of outcome in more than 1000 cases

OBJECTIVE

The purpose of this study was to review our experience over the last decade with the dorsalis pedis bypass for ischemic limb salvage in patients with diabetes mellitus.

METHODS

The study was a retrospective analysis of a computerized vascular registry and chart review. From January 10, 1990 to January 11, 2000, 1032 bypasses to the dorsalis pedis artery were performed in 865 patients (27.6% of the 3731 lower extremity arterial bypass procedures performed in that time period). Five hundred ninety-seven patients (69%) were male, with a mean age of 66.8 years. Ninety-two percent had diabetes mellitus. All procedures were done for limb salvage. Conduits included 317 nonreversed saphenous vein (30.7%), 273 in situ (26.4%), 235 reversed vein (22.8%), 170 arm vein (16.5%), 35 other vein (3.4%), and two polytetrafluoroethylene (0.2%) grafts. The inflow arteries were as follows: 294 common femoral (28.5%), 550 popliteal (53.2%), 114 superficial femoral (11%), and 74 other (7.2%).

RESULTS

The mortality rate within 1 month of surgery was 0.9%, and 42 grafts (4.2%) failed in the same interval, although 13 were successfully revised. In a follow-up period that ranged from 1 to 120 months (mean, 23.6 months), primary patency, secondary patency, limb salvage, and patient survival rates were 56.8%, 62.7%, 78.2%, and 48.6%, respectively at 5 years and 37.7%, 41.7%, 57.7%, and 23.8% at 10 years. Both polytetrafluoroethylene grafts failed in less than 1 year. Primary graft patency was worse in female patients (46.5% female versus 61.6% male at 5 years; P <.009) but better in patients with diabetes (65.9% diabetes mellitus versus 56.3% non-diabetes mellitus at 4 years; P <.04). Saphenous vein grafts performed better than all other conduits with a secondary patency rate of 67.6% versus 46.3% at 5 years (P <.0001). Multivariate analysis showed that length of stay greater than 10 days and dorsalis pedis bypass for the surgical indication of previous graft occlusion were independently predictive of worse graft patency at 1 year and use of saphenous vein as conduit was predictive of better patency.

CONCLUSION

Dorsalis pedis bypass is durable with a high likelihood of ischemic foot salvage over many years. Saphenous vein is the preferred conduit when available. Short vein grafts from distal inflow sites are possible in more than 50% of cases. These results justify the routine use of pedal arterial reconstruction for patients with diabetes with ischemic foot complications.

Leukocytosis and ischemic vascular disease morbidity and mortality: is it time to intervene?

The association between leukocytosis and increased morbidity and mortality of ischemic vascular disease has been observed for more than half a century, and recent studies in >350,000 patients confirm the robustness of the association and the dramatically higher relative and absolute acute and chronic mortality rates in patients with high versus low leukocyte counts. Although there is reason to believe that the association is not causal (that is, that leukocytosis is simply a marker of inflammation), there is also reason to believe that the leukocytosis directly enhances acute thrombosis and chronic atherosclerosis. Leukocytosis also is associated with poor prognosis and vaso-occlusive events in patients with sickle cell disease, and experimental data suggest a direct role for leukocytes in microvascular obstruction. The only way to test whether leukocytes contribute directly to poor outcome in ischemic cardiovascular disease is to assess the effect of modifying leukocyte function or number. Because selective blockade of leukocyte integrin alphaMbeta2 and P-selectin have thus far been disappointing as therapeutic strategies in human cardiovascular and cerebrovascular disease, I discuss the potential risks and benefits of short-term treatment with hydroxyurea to decrease the leukocyte count in select populations of patients at the highest risk of short-term death.

Hypoxic hepatitis: clinical and hemodynamic study in 142 consecutive cases

The centrilobular liver cell necrosis observed in hypoxic hepatitis is generally attributed to failure of hepatic blood perfusion. Accordingly, this injury of the liver is commonly recognized under the terms "shock liver" or "ischemic hepatitis." During a 10-year period, 142 episodes of hypoxic hepatitis were consecutively identified in the intensive care unit of a general hospital, and the clinical, biological, and hemodynamic parameters were prospectively collected on individual files. We conducted the current study to assess retrospectively the role of the hemodynamic mechanisms of tissue hypoxia: ischemia, passive venous congestion, and hypoxemia. Among the 142 episodes of hypoxic hepatitis, 138 were separated in 4 main groups based on clinical features: decompensated congestive heart failure (80 cases), acute cardiac failure (20 cases), exacerbated chronic respiratory failure (19 cases), and toxic/septic shock (19 cases). An elementary hemodynamic evaluation, including blood pressure, central venous pressure, and arterial blood gas analysis, was carried out in every episode and a more complete hemodynamic assessment through pulmonary artery catheterization was performed in 61 episodes. The hemodynamic mechanisms responsible for hypoxic hepatitis were different in the 4 groups. In congestive heart failure and acute heart failure, the hypoxia of the liver resulted from decreased hepatic blood flow (ischemia) due to left-sided heart failure and from venous congestion secondary to right-sided heart failure. In chronic respiratory failure, liver hypoxia was mainly due to profound hypoxemia. In toxic/septic shock, oxygen delivery to the liver was not decreased but oxygen needs were increased, while the liver was unable to use oxygen properly. In all conditions underlying hypoxic hepatitis, except toxic/septic shock, a shock state was observed in only about 50% of the cases. Therefore, the expressions "shock liver" or "ischemic hepatitis" are misleading and should be replaced by the more general term "hypoxic hepatitis."

Cytoplasmic stress granules: Dynamic modulators of cell signaling and disease

Stress granule (SG) assembly is a conserved cellular strategy to minimize stress-related damage and promote cell survival. Beyond their fundamental role in the stress response, SGs have emerged as key players for human health. As such, SG assembly is associated with cancer, neurodegenerative disorders, ischemia, and virus infections. SGs and granule-related signaling circuits are therefore promising targets to improve therapeutic intervention for several diseases. This is clinically relevant, because pharmacological drugs can affect treatment outcome by modulating SG formation. As membraneless and highly dynamic compartments, SGs regulate translation, ribostasis and proteostasis. Moreover, they serve as signaling hubs that determine cell viability and stress recovery. Various compounds can modulate SG formation and dynamics. Rewiring cell signaling through SG manipulation thus represents a new strategy to control cell fate under various physiological and pathological conditions.

Poor outcomes in patients who do not receive intravenous tissue plasminogen activator because of mild or improving ischemic stroke

BACKGROUND AND PURPOSE

Some patients with mild or improving ischemic stroke symptoms do not receive intravenous tissue plasminogen activator (tPA) because they look "too good to treat" (TGT); however, some have poor outcomes.

METHODS

We retrospectively analyzed data from a prospective single-center study between 2002 and 2004. TGT patients were those arriving within 3 hours of symptom onset and not treated with intravenous tPA solely because of mild or improving symptoms.

RESULTS

Of 128 patients presenting within 3 hours, 41 (34%) were not given tPA because of mild or improving stroke. Of the TGT patients, 11 of 41 (27%) died or were not discharged home because of neurological worsening (n=6) or persistent "mild" neurological deficit (n=5). No single variable at presentation was associated with death or lack of home discharge. There were 10 of 41 TGT patients (24%) who had > or =4-point improvement in National Institutes of Health Stroke Scale score before tPA decision; these patients were more likely to have subsequent neurological worsening (relative risk, 4.1, 95% CI, 1.1 to 15.4; P=0.05).

CONCLUSIONS

A substantial minority of patients deemed too good for intravenous tPA were unable to be discharged home. A re-evaluation of the stroke severity criteria for tPA eligibility may be indicated.

Tumor necrosis factor alpha, but not Fas, mediates hepatocellular apoptosis in the murine ischemic liver

BACKGROUND & AIMS

Apoptosis of hepatocytes is a central feature of ischemic injury in the liver. The aim of this study was to identify extracellular inducers of apoptosis in the murine ischemic liver.

METHODS

Involvement of tumor necrosis factor (TNF)-alpha and Fas signaling was evaluated using various knockout mice (TNF-receptor 1 [TNF-R1]-/-, Fas[lpr]-/-, and Fas ligand[gld]-/-) and wild-type mice pretreated with pentoxifylline, an inhibitor of TNF-alpha synthesis.

RESULTS

Expression of TNF-alpha was increased after ischemia and reperfusion in wild-type mice and TNF-R1-deficient mice when compared with sham-operated animals. Pentoxifylline prevented up-regulation of TNF-alpha expression. Inhibition of TNF-alpha resulted in significant decrease of serum aspartate aminotransferase levels and prolonged animal survival. Markers of apoptosis (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, cytochrome C release, and caspase 3 activity) were consistently decreased, and animal survival was prolonged after blocking TNF-alpha. In contrast, inhibition of Fas signaling did not alter parameters of tissue injury or apoptosis, and animal survival remained unchanged.

CONCLUSIONS

We identify TNF-alpha as a crucial inducer of apoptotic cell death in the ischemic liver. A role for Fas could not be identified. These findings may lead to novel strategies to prevent ischemic injury of the liver.

Acute mesenteric ischemia: the challenge of gastroenterology

Intestinal ischemia has been classified into three major categories based on its clinical features, namely, acute mesenteric ischemia (AMI), chronic mesenteric ischemia (intestinal angina), and colonic ischemia (ischemic colitis). Acute mesenteric ischemia is not an isolated clinical entity, but a complex of diseases, including acute mesenteric arterial embolus and thrombus, mesenteric venous thrombus, and nonocclusive mesenteric ischemia (NOMI). These diseases have common clinical features caused by impaired blood perfusion to the intestine, bacterial translocation, and systemic inflammatory response syndrome. Reperfusion injury, which exacerbates the ischemic damage of the intestinal microcirculation, is another important feature of AMI. There is substantial evidence that the mortality associated with AMI varies according to its cause. Nonocclusive mesenteric ischemia is the most lethal form of AMI because of the poor understanding of its pathophysiology and its mild and nonspecific symptoms, which often delay its diagnosis. Mesenteric venous thrombosis is much less lethal than acute thromboembolism of the superior mesenteric artery and NOMI. We present an overview of the current understanding of AMI based on reported evidence. Although AMI is still lethal and in-hospital mortality rates have remained high over the last few decades, accumulated knowledge on this condition is expected to improve its prognosis.

Acute mesenteric ischemia: diagnosis with contrast-enhanced CT

PURPOSE

To evaluate the accuracy of dynamic, contrast material-enhanced computed tomography (CT) in the diagnosis of acute mesenteric ischemia.

MATERIALS AND METHODS

Reviewers blinded to patient diagnoses retrospectively compared the CT scans in a study group with those in a control group. The study group comprised 39 consecutive patients (23 men, 16 women; aged 55-88 years) with surgically proved acute mesenteric ischemia. The control group comprised 24 patients (13 men, 11 women; aged 50-82 years) with suspected acute mesenteric ischemia that was disproved at surgery.

RESULTS

For the diagnosis of acute mesenteric ischemia, each of the following findings had a specificity of more than 95% and a sensitivity of less than 30%: arterial or venous thrombosis, intramural gas, portal venous gas, focal lack of bowel-wall enhancement, and liver or splenic infarcts. When CT was used in the diagnosis of suspected acute mesenteric ischemia, the detection of at least one of these signs resulted in a sensitivity of 64% (25 of 39; confidence interval, 0.49, 0.79), a specificity of 92% (22 of 24; confidence interval, 0.81, 1.00), and an accuracy of 75% (47 of 63; confidence interval, 0.64, 0.86).

CONCLUSION

Dynamic, contrast-enhanced CT is a valuable tool in the diagnosis of and determination of prognosis in acute mesenteric ischemia.

Revascularization of a specific angiosome for limb salvage: does the target artery matter?

Ischemic wounds of the lower extremity can fail to heal despite successful revascularization. The foot can be divided into six anatomic regions (angiosomes) fed by distinct source arteries arising from the posterior tibial (three), anterior tibial (one), and peroneal (two) arteries. This study investigated whether bypass to the artery directly feeding the ischemic angiosome had an impact on wound healing and limb salvage. Retrospective analysis was performed for 52 nonhealing lower extremity wounds (48 patients) requiring tibial bypass over a 2-year period. Preoperative arteriograms were reviewed to determine arterial anatomy relative to each wound's specific angiosome and bypass anatomy. Patients were divided into two groups; direct revascularization (DR, bypass to the artery directly feeding the ischemic angiosome) or indirect revascularization (IR, bypass unrelated to the ischemic angiosome). Wound outcome was analyzed with regard to the endpoints of complete healing, amputation, or death unrelated to the wound. Time to healing was also noted for healed wounds. Based on preoperative arteriography, 51% (n = 27) of the wounds received DR to the ischemic angiosome, while 49% (n = 25) underwent IR. There were no statistically significant differences in the comorbidities of the two groups. Revascularization was via tibial bypass using the saphenous vein (n = 34, 65%) or polytetrafluoroethylene with a distal vein patch (n = 18, 35%). Bypasses were performed to the anterior tibial (n = 22, 42%), posterior tibial (n = 17, 33%), or peroneal (n = 13, 25%) arteries based on the surgeon's judgment. One bypass failed in the perioperative period and was excluded from the analysis. The remaining bypasses were patent at the time of wound analysis. Due to a 17% mortality rate during follow-up, 43 wounds were available for endpoint analysis. This analysis demonstrated that 77% of wounds (n = 33) progressed to complete healing and 23% of wounds (n = 10) failed to heal with resultant amputation. In the DR group, there was 91% healing with a 9% amputation rate. In the IR group, there was 62% healing with a 38% amputation rate (p = 0.03). In those wounds that did heal, total time to healing was not significantly different--DR 162.4 days versus IR 159.8 days (p = 0.95). Revascularization plays a crucial role in the treatment of ischemic lower extremity wounds. We believe that direct revascularization of the angiosome specific to the anatomy of the wound leads to a higher rate of healing and limb salvage. Although many factors must be considered in choosing the target artery for revascularization, consideration should be given to revascularization of the artery directly feeding the ischemic angiosome.

Superiority of clopidogrel versus aspirin in patients with prior cardiac surgery

BACKGROUND

After coronary artery bypass surgery, patients have a high cumulative rate of graft closure and recurrent ischemic events. We sought to determine whether antiplatelet therapy with clopidogrel would be more effective than aspirin, the accepted standard, in these patients.

METHODS AND RESULTS

The event rates for all-cause mortality, vascular death, myocardial infarction, stroke, and rehospitalization were determined for the 1480 patients with a history of cardiac surgery randomized to either clopidogrel or aspirin in a trial of 19 185 patients. The event rate per year of vascular death, myocardial infarction, stroke, or rehospitalization was 22.3% in the 705 patients randomized to aspirin and 15.9% in the 775 patients randomized to clopidogrel (P:=0.001). A risk reduction was also seen in each of the individual end points examined, including a 42.8% relative risk reduction in vascular death in patients on clopidogrel versus aspirin (P:=0.030). In a multivariate model incorporating baseline clinical characteristics, clopidogrel therapy was independently associated with a decrease in vascular death, myocardial infarction, stroke, or rehospitalization in patients with a history of cardiac surgery, with a 31.2% relative risk reduction (95% CI, 15.8 to 43.8; P:=0.0003). Although clopidogrel therapy was efficacious in the entire Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) population, multivariate analysis demonstrated that patients with previous cardiac surgery derived particular benefit (P:=0.015).

CONCLUSION

Compared with aspirin, clopidogrel therapy results in a striking reduction in the elevated risk for recurrent ischemic events seen in patients with a history of prior cardiac surgery, along with a decreased risk of bleeding.

Determinants of mortality and treatment outcome following surgical interventions for acute mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia (AMI) is associated with high morbidity and mortality due in part to its diagnostic difficulty and operative challenges. The purpose of this study was to review our experience of surgical management in patients with this condition and to identify variables associated with adverse outcomes following surgical interventions.

METHODS

Hospital records and clinical data of all patients undergoing surgical interventions for AMI were reviewed during a recent 12-year period. Clinical outcomes as well as factors influencing mortality were analyzed.

RESULTS

A total of 72 patients (41 females, overall mean age 65 years, range 34 to 83 years) were included in the study. Thrombosis and embolism were the cause of AMI in 48 patients (67%) and 24 patients (33%), respectively. Abdominal pain was the most common presenting symptom (96%), followed by nausea (56%). Preoperative angiogram was performed in 61 patients (85%). All patients underwent operative interventions, which included thromboembolectomy (n = 22, 31%), mesenteric bypass grafting (n = 33, 46%), patch angioplasty (n = 9, 12%), reimplantation (n = 5, 7%), and endarterectomy (n = 3, 4%). Bowel resection was necessary in 22 patients (31%) during the initial operation, and second-look operation was performed in 38 patients (53%). Perioperative morbidity and 30-day mortality rates were 39% and 31%, respectively. Univariate analysis showed renal insufficiency (P < .02), age >70 (P < .001), metabolic acidosis (P < .02), and symptom duration (P < .005), and bowel resection in second-look operations (P < .01) were associated with mortality. Logistic regression analysis showed age >70 (P = .03) and prolonged symptom duration (P = .02) were independent predictors of mortality.

CONCLUSIONS

Elderly patients and those with a prolonged duration of symptoms had worse outcomes following surgical intervention for AMI. A high index of suspicion with prompt diagnostic evaluation may reduce time delay prior to surgical intervention, which may lead to improved patient survival. Aggressive surgical intervention should be performed as promptly as possible in patients once the diagnosis of AMI is made.

Current results of open revascularization for chronic mesenteric ischemia: a standard for comparison

OBJECTIVE

Questions remain concerning the optimal site of graft origin and the extent of revascularization necessary to achieve excellent results for chronic mesenteric ischemia (CMI). Endovascular therapy also is performed for CMI. These factors prompted us to review our results to provide a current standard.

METHODS

Ninety-eight patients who underwent operation for CMI from 1989 to 1998 were reviewed. Patients with acute ischemia and arcuate ligament syndrome were excluded.

RESULTS

Seventy-six women (78%) and 22 men (22%), with an average age of 66 years (range, 36 to 87 years), participated in the study. Abdominal pain was present in 95 patients (97%), and weight loss in 92 patients (94%). The superior mesenteric artery was severely diseased (70% to 99% stenosis or occlusion) in 90 patients (92%), the celiac artery in 81 patients (83%), and both arteries in 76 patients (78%). Bypass grafts were performed in 91 patients (93%), 77 antegrade and 14 retrograde. Of the other seven patients, five had endarterectomies, one reimplantation, and one patch angioplasty. Multivessel reconstruction was performed in 79 patients (81%), and single-vessel reconstruction in 19 (19%). Twelve patients had concomitant aortic reconstruction. Three early graft thromboses were seen. Five hospital deaths occurred (5.1%); one case had concomitant aortic reconstruction (1/12 versus 4/86; P = not significant). All five patients who died were older than 70 years (5/41 versus 0/57; P =.011). The median follow-up period was 1.9 years (range, 0 to 9.6 years). Follow-up was complete in all survivors. The 1-year, 5-year, and 8-year survival rates were 83%, 63%, and 55%, respectively. These rates were worse than the rates of the age-matched/gender-matched control subjects (P <.001). Survival was worse in patients greater than 70 years of age (P =.0013). Survival was unaffected by the number of vessels revascularized. The patients with retrograde grafts had decreased median survival rates (4.0 versus 5.7 years; P =.026), but they were older (75 versus 65 years; P =.0013). The 1-year and 5-year symptom-free survival rates were 95% and 92%, respectively. Symptoms recurred in six patients (6%): four had recurrent stenosis/occlusion and two had patent grafts. Symptom-free survival was unaffected by the number of vessels revascularized or by graft orientation.

CONCLUSION

Operation for CMI was successful for most patients, with low operative mortality and excellent long-term relief of symptoms. Selective concomitant aortic procedures did not increase mortality rates. The rate of symptomatic recurrences was not different for single-vessel versus multiple-vessel reconstructions or for antegrade versus retrograde grafts. Patients older than 70 years had increased operative mortality and decreased survival rates. Endovascular therapy may be appropriate for this subset of patients.