Acute thrombo-embolic occlusion of the superior mesenteric artery: a prospective study in a well defined population.

OBJECTIVES: to characterize the clinical presentation of patients with acute thrombo-embolic occlusion of the superior mesenteric artery (SMA). DESIGN: prospective study. MATERIALS: twenty-four consecutive patients admitted to Blekinge County Hospital, Karlskrona, Sweden, with acute thrombo-embolic occlusion of the SMA, over a three-year period from April 1999 through March 2002. METHODS: clinical data were registered prospectively. Incidence, diagnostic procedures and factors associated with survival were analysed. RESULTS: the diagnosis was verified at operation in 20, and at autopsy in 4 patients. The incidence was 5.3 per 100 000 inhabitants per year. Among the 20 patients with embolic disease, atrial fibrillation was present in 95%, synchronous embolic events in 30% and warfarin treatment in 10%. D-dimer was elevated on admission in 13/13. Four patients were diagnosed at first consultation. Fifteen underwent curative revascularisation (6) or bowel resection only (9). Five were alive at one-year follow-up, of whom one had short bowel syndrome. Length of bowel ischaemia predicted institutional (p = 0.004) and one-year mortality (p = 0.005). CONCLUSIONS: the incidence was higher than expected. Embolic occlusions predominated. Old age, atrial fibrillation, severe abdominal pain and synchronous embolus suggest the diagnosis of acute bowel ischaemia. Length of bowel ischaemia predicted outcome.     

Minimal access closure of patent foramen ovale: is it also recommended for patients with paradoxical emboli?

BACKGROUND: To investigate the outcome of the port-access approach for patent foramen ovale (PFO) closure and to identify the long-term risk of recurrent thromboembolic events in the paradoxical embolus subgroup after closure. METHODS: Between 1997 and 2001, 31 patients underwent PFO closure using the port-access approach. Twelve of the 31 patients underwent PFO closure secondary to at least one paradoxical embolic event leading to either transient ischemic attack or cerebral infarction. All patients were followed longitudinally with office visits and telephone interviews. RESULTS: The mean age was 47 years (range 18 to 85 years). All procedures were completed successfully without conversion to median sternotomy. The mean duration of aortic occlusion and cardiopulmonary bypass for all patients (n = 31) was 32 minutes (range 17 to 55 minutes) and 72 minutes (range 40 to 124 minutes), respectively. Postoperative complications included pneumonia/pulmonary embolus (n = 1), transient atrial fibrillation (n = 3, 9.7%), and exploration for bleeding (n = 3, 9.7%). No deaths were recorded. All patients were assessed using transesophageal echocardiography, and the closure of the PFO was documented. The average length of hospital stay was 3.8 days (range 2 to 10 days) for patients with paradoxical emboli. The mean follow-up period for the paradoxical embolus subgroup was 23 months (range 4 to 45 months). One patient was lost to follow-up. Neither transient ischemic attack nor cerebral infarction recurred during follow-up. CONCLUSIONS: The port-access approach to PFO closure is a safe and effective procedure, with acceptable initial experience outcome and excellent low-risk rate of recurrent thromboembolic events.     

Revascularization of the superior mesenteric artery after acute thromboembolic occlusion

BACKGROUND: The outcome and prognostic factors after revascularization of acute thromboembolic occlusion of the superior mesenteric artery (SMA) are poorly documented. METHODS: Sixty patients with acute thromboembolic occlusion of the SMA had revascularization procedures at 21 hospitals from 1987 to 1998. They were registered prospectively in the Swedish Vascular Registry. Patient files were analysed retrospectively. RESULTS: The median age of the patients was 76 years; 73 per cent suffered from cardiac disease and 23 per cent had previous vascular surgery. Onset of symptoms was classified as sudden (30 per cent), acute (33 per cent) or insidious (37 per cent). The occlusions were thought to be either embolic (67 per cent) or thrombotic (33 per cent). The diagnosis was suspected on first examination in 32 per cent of patients, a group whose median time to operation was shorter (P = 0.01). Fifty-eight patients had an exploratory laparotomy and subsequent revascularization, and two were treated with thrombolysis alone. Second-look laparotomy was performed in 41, and third look in eight patients; 19 required an additional bowel resection. The overall mortality rates were 43, 52, 60 and 67 per cent at 30 days, discharge, 1 and 5 years, respectively. No patient was dependent on intravenous nutrition after 1 year. Previous vascular surgery resulted in a higher institutional mortality rate (79 per cent; P = 0.02). Patients who had a sudden onset of symptoms outside hospital had a better outcome (mortality rate 27 per cent; P = 0.02). CONCLUSION: Many non-diagnostic radiological examinations were performed and a routine second-look is warranted. The results suggest that attempts at revascularization procedures for acute mesenteric ischaemia may improve the outcome.     

Preliminary study of D-dimer as a possible marker of acute bowel ischaemia

BACKGROUND: Occlusion of the superior mesenteric artery (SMA) demands prompt recognition and diagnosis. No accurate diagnostic method is available. The aim of this study was to determine whether the fibrinolytic marker D-dimer is a useful early marker of acute bowel ischaemia. METHODS: Fourteen patients suspected of having acute bowel ischaemia were analysed for an increase in plasma D-dimer level. RESULTS: Six patients had embolic or thrombotic occlusion of the SMA and all had significantly higher D-dimer levels than those without thromboembolic occlusion (P < 0.05). Four patients with strangulation of the small bowel due to adhesions and one with a ruptured aortic aneurysm also had raised D-dimer values. CONCLUSION: In patients with suspected thromboembolic occlusive disease of the SMA, a raised level of D-dimer indicated the presence of acute bowel ischaemia, whatever the cause. A more extensive prospective study is needed to evaluate a potential survival benefit using the test as a marker of the need for urgent laparotomy.     

Detection of left heart thrombus by echocardiography is not essential before peripheral arterial thrombolysis.

Left heart thrombus has been regarded as a contraindication to thrombolysis. In this prospective study the role of echocardiography before thrombolysis in the cardiac assessment of 51 patients undergoing thrombolysis for a peripheral arterial occlusion was evaluated. Ten patients with positive echocardiograms were identified. Echocardiography contributed to the diagnosis of embolus in one patient. All eight patients with embolic arterial occlusions were successfully recanalized, comparing favourably with a success rate of 58% in patients with thrombotic occlusions. There were no embolic complications during thrombolytic treatment or in the subsequent 30 days. We conclude that thrombolysis can be performed safely despite the presence of left heart thrombus.     

Acute embolic occlusion of the distal aorta

PURPOSE: Acute occlusion of the abdominal aorta requires rapid diagnosis and intervention to prevent loss of life or limb. The overall mortality due to embolic occlusion is reported to be over 30%. The most common source of emboli is the heart, secondary to atrial fibrillation or myocardial infarction. METHODS: A patient is herein presented who arrived at the emergency department 6 hours after onset of classic signs of acute arterial occlusion. RESULTS: She had a saddle embolus of the distal abdominal aorta with extension of the clot into both iliac and femoral arteries. CONCLUSIONS: Heparin therapy and embolectomy successfully reestablished blood flow. The etiology, presentation and management of aortoiliac occlusion is discussed.     

D-dimer testing in patients with suspected acute thromboembolic occlusion of the superior mesenteric artery

BACKGROUND: There is no accurate non-invasive method available for the diagnosis of acute thromboembolic occlusion of the superior mesenteric artery (SMA). The aim of this study was to assess the diagnostic properties of the fibrinolytic marker D-dimer. METHODS: From September 2000 to April 2003 consecutive patients aged over 50 years admitted to hospital with acute abdominal pain were studied. Patients with possible acute SMA occlusion at presentation had blood samples taken within 24 h of the onset of the pain for analysis of D-dimer, plasma fibrinogen, activated partial thromboplastin time, prothrombin time and antithrombin. The value of D-dimer testing to diagnose SMA occlusion was assessed by means of likelihood ratios. RESULTS: Nine of 101 patients included had acute SMA occlusion. The median D-dimer concentration was 1.6 (range 0.4-5.6) mg/l, which was higher than that in 25 patients with inflammatory disease (P = 0.007) or in 14 patients with intestinal obstruction (P = 0.005). The combination of a D-dimer level greater than 1.5 mg/l, atrial fibrillation and female sex resulted in a likelihood ratio for acute SMA occlusion of 17.5, whereas no patient with a D-dimer concentration of 0.3 mg/l or less had acute SMA occlusion. CONCLUSION: D-dimer testing may be useful for the exclusion of patients with suspected acute SMA occlusion.     

Renal artery emboli: The role of surgical treatment

Twelve cases of emboli to the renal artery (one of which was recurrent) were reviewed. In seven patients, emboli were unilateral and the opposite kidney was functional. In five patients, emboli were bilateral or occurred in a solitary kidney, leading to anuria. Cardiac rhythm disorders were encountered in eight patients and were responsible for emboli in other areas in three. Arteriography in ten patients demonstrated seven complete truncal occlusions (one bilateral), two incomplete truncal occlusions, and one distal embolus. One patient with a distal embolus was treated by heparin alone with satisfactory results. One patient in poor general condition was treated with intraarterial streptokinase, resulting in incomplete lysis of the clot. The five patients with anuria were operated on: four regained satisfactory renal function whereas the other patient died. In five patients without anuria who were operated upon, renal function returned to normal in four, and one patient required nephrectomy. Surgical treatment is imperative with anuria and is indicated in unilateral emboli with a functional contralateral kidney, especially when there is complete occlusion of the renal trunk. If the embolus is recent, intraarterial fibrinolytic treatment or percutaneous embolectomy can be attempted, but these techniques are not of proven efficacy. Patients with distal emboli or contraindications to operation should be treated by anticoagulant therapy, alone or with local fibrinolytic treatment.     

Can varying flow velocity across an arterial anastomosis prevent thromboembolic injury?

In this study, simulated “poor” repairs applied to transverse incisions in the iliac arteries of 40 rats were the basis for comparing the effect of variations in blood flow on throm-boembolism. Using vital microscopy and digital image processing, we performed 2 experiments. In the first experiment (n = 20), the reduction of post-repair blood flow by approximately 50% resulted in an 83% reduction in the total number of emboli appearing in the microcirculation of the cremaster muscle distal to the repair. In the second experiment (n = 20), the same reduction in blood flow typically resulted in larger repair-site thrombi which required significantly more time to grow to their maximum size. We conclude that reducing pedicle artery blood flow to approximately half in our rat model during reperfusion can protect the downstream micro-circulation from embolic injury without increasing the incidence of thrombotic occlusion. © 1995 Wiley-Liss, Inc.     

Thromboembolic complications after mitral valve replacement with Hancock xenograft

Case histories of 140 patients who had mitral valve replacement with the Hancock xenograft were reviewed according to the incidence of thromboembolic complications. There were 16 patients with preoperative and/or postoperative low-output syndrome (Group A.) Eight of these patients died, and six had autopsies which showed major thrombi on the heterograft valve. In 126 long-term survivors (followed 1 to 33 months) nine thromboembolic events occurred (thromboembolic incidence 5.3 percent per patient-year). All patients with emboli were in atrial fibrillation. Additional predisposing factors included a history of systemic emboli and the presence of atrial clots at the time of surgery. The majority (7/9) of emboli occurred during the first 3 postoperative months. Two emboli occurred immediately following the operation (before oral anticoagulation therapy could have been begun). Five occurred in patients who were not on anticoagulation (Group B) and two occurred under warfarin treatment (Group C). There was no thromboembolic event in patients taking aspirin (Group D). It is concluded that hemodynamically stable patients have a decreased risk of thromboembolism and do not require anticoagulation. Patients with atrial fibrillation have an increased thromboembolic risk and should be on a regimen of warfarin for 3 months postoperatively and then on aspirin therapy.     

Clinical significance of free-floating venous thrombi

To evaluate the fate of free-floating venous thrombi, venous duplex scans of 5238 consecutive lower extremities over a 2 1/2 year period were reviewed. Acute deep venous thrombosis was found in 732 cases. Eighty-two free-floating deep venous thrombi were diagnosed in 73 of these patients. Nine of 72 patients (13%) had pulmonary emboli as diagnosed by ventilation perfusion scanning or pulmonary angiography or both. Seven of these patients (78%) had a pulmonary embolus before the initial duplex scan. Two (22%) had a pulmonary embolus after the diagnosis of free-floating thrombus. Thirty-three of 73 patients (45%) had follow-up of free-floating thrombi by duplex scanning performed in the acute period (less than 30 days): 18 (55%) showed attachment of the free-floating thrombus, three (9%) showed progression in size of the free-floating tail, and eight (24%) showed decrease in size or resolution of the free-floating thrombus. Four (12%) showed persistent thrombus without evidence of resolution, propagation, or attachment. In conclusion, free-floating venous thrombi occurred in 10% of cases of acute deep venous thrombosis. Only 13% of free-floating thrombi were associated with clinically significant pulmonary emboli, confirmed by ventilation perfusion scanning. Usually the embolus occurred before diagnosis of free-floating thrombus. Most free-floating thrombi followed noninvasively by duplex scanning do not embolize, but rather they become attached to the vein wall or resolve.     

Mural thrombus of the aorta: an important, frequently neglected cause of large peripheral emboli.

The association between white thrombus in the aorta and multiple embolic occlusions of peripheral vessels was made 22 years ago. However, mural thrombus has been neglected as a major cause of embolus because the process was attributed to paradoxical effects of heparin. Our recent experience indicates it is a more generalized problem. During the past five years, AP and lateral abdominal aortograms demonstrated the presence of large filling defects within the lumen of the aorta in 20 of 39 patients with sudden occlusion of a distal artery. Thirteen patients were not on heparin. These 3.4 X 1-2 cm defects were present anywhere from T-10 to the aortic bifurcation and were suprarenal in ten patients. The 20 patients had a total of 36 separate embolic events, with five patients experiencing seven occlusions of renal or superior mesenteric arteries. Serious medical problems coexisted, and all patients had at least two of five important "risk factors." These were heart disease, recent thrombophlebitis, heparin therapy, abdominal atherosclerosis and postoperative status. Catheter embolectomy alone was associated with recurrent embolization in four of six patients. Three patients died and two required amputation. Of 12 patients treated by embolectomy combined with open aortotomy, recurrent embolization occurred in none, death in one and amputation in two. All patients with visceral artery occlusions survived with normal function of the previously occluded structure. We urge wider application of abdominal angiography in order to treat more appropriately a sizable proportion of patients whose distal emboli originated from large chunks of white thrombus in the abdominal aorta.     

Ulmer Therapiemodell

The therapy of limb-threatening ischaemia is still a matter of controversy . The aim of this retrospective study was to determine whether the transcutaneous approach is an alternative to open surgery. We investigated and compared surgical and percutaneous interventional methods in the treatment of both embolic and thrombotic vascular occlusions in patients with pre-existing arteriosclerotic disease with the aim of establishingtherapy guidelines for the therapy of acute limb ischaemia. From 1994 to 1997, a total of 197 patients with acute limb ischaemia were treated. Of 80 patients with embolic occlusions, 23 (28.8%) were treated using percutaneous interventional methods, while the remaining 57 (71.2%) underwent surgery. There was no significant difference in the rate of limb salvage between the groups treated using the transcutaneous approach (86%) and open surgery (88%). In 117 patients with thrombotic occlusions and pre-existing arteriovascular disease, percutaneous treatment was successful in 61% of the 38 patients selected for percutaneous treatment and in 62% of patients undergoing surgery. Another 26 patients underwent additional interventional measures intraoperatively. The rate of limb salvage was 62% for the surgical group as a whole. Percutaneous mechanical thrombectomy represents a viable therapeutic alternative to surgical or surgical-interventional modalities, particularly in those patients with occlusions consisting of soft, embolic material and in those with occlusions occurring in infrapopliteal vessels. An interdisciplinary approach to defining the indications for each of these methods should be taken based on the individual patient’s clinical and angiographic findings. Additional intraoperative endovascular procedures increase the range of therapeutic options and permit optimal revascularization of vessels both proximal and distal to the site of occlusion.     

Mesenteric venous thrombosis with transmural intestinal infarction: a population-based study

OBJECTIVE: To determine the cause-specific mortality from and incidence of transmural intestinal infarction caused by mesenteric venous thrombosis (MVT) in a population-based study and to evaluate the findings at autopsy by evaluating autopsies and surgical procedures. METHODS: All clinical (n = 23,446) and forensic (n = 7569) autopsies performed in the city of Malm? between 1970 and 1982 (population 264,000 to 230,000) were evaluated. The autopsy rate was 87%. The surgical procedures were performed in 1970, 1976, and 1982. Autopsy protocols coded for intestinal ischemia or mesenteric vessel occlusion, or both, were identified in a database. In all, 997 of 23,446 clinical and 9 of 7,569 forensic autopsy protocols were analyzed. A 3-year sample of the surgical procedures, comprising 21.3% (11,985 of 56,251) of all operations performed during the entire study period, was chosen to capture trends of diagnostic and surgical activity. In a nested case-control study within the clinical autopsy cohort, four MVT-free controls, matched for gender, age at death, and year of death were identified for each fatal MVT case to evaluate the clinical autopsy findings. RESULTS: Four forensic and 23 clinical autopsies demonstrated MVT with intestinal infarction. Seven patients were operated on, of whom six survived. The cause-specific mortality ratio was 0.9:1000 autopsies. The incidence was 1.8/100,000 person years. At autopsy, portal vein thrombosis and systemic venous thromboembolism occurred in 2 of 3 and 1 of 2 of the cases, respectively. Obesity was an independent risk factor for fatal MVT (P =.021). CONCLUSIONS: The estimated incidence of MVT with transmural intestinal infarction was 1.8/100,000 person years. Portal vein thrombosis, systemic venous thromboembolism and obesity were associated with fatal MVT.     

Recurrent subarachnoid hemorrhage associated with aminocaproic acid therapy and acute renal artery thrombosis. Case report.

Epsilon aminocaproic acid (EACA) has been used to prevent rebleeding in patients with subarachnoid hemorrhage (SAH). Although this agent does decrease the frequency of rebleeding, several reports have described thrombotic complications of EACA therapy. These complications have included clinical deterioration and intracranial vascular thrombosis in patients with SAH, arteriolar and capillary fibrin thrombi in patients with fibrinolytic syndromes treated with EACA, or other thromboembolic phenomena. Since intravascular fibrin thrombi are often observed in patients with fibrinolytic disorders, EACA should not be implicated in the pathogenesis of fibrin thrombi in patients with disseminated intravascular coagulation or other "consumption coagulopathies." This report describes subtotal infarction of the kidney due to thrombosis of a normal renal artery. This occlusion occurred after EACA therapy in a patient with SAH and histopathological documentation of recurrent SAH. The corresponding clinical event was characterized by marked hypertension and abrupt neurological deterioration.     

The relationship between plasma MMP-1, -7, -8 and -13 levels and embolic potential during carotid endoluminal intervention.

BACKGROUND: Patients undergoing carotid endoluminal intervention are at risk of embolic stroke even with the use of distal protection devices. Matrix metalloproteinases (MMPs) have been implicated as a causal factor in plaque instability leading to spontaneous embolisation. We investigated whether plasma MMP levels correlated with the embolisation during carotid endoluminal intervention. METHODS: Thirty circumferentially intact carotid endarterectomy specimens were subjected to a standardised angioplasty procedure in a pulsatile ex vivo model. Emboli collected in a series of distal filters were counted and sized. Plasma samples were collected pre-operatively and analysed for MMP-7 and MMP-8 levels using Western immunoblotting. MMP-1 and MMP-13 levels were determined using ELISA. Emboli number and maximum size were correlated with plasma levels of the MMPs using Spearmans rank. RESULTS: Total MMP-8 levels were related to maximum embolus size (r=0.442, p=0.005) but not emboli number (r=0.342, p=0.052). MMP-1, -7 and -13 were not correlated with either emboli number or with maximum embolus size. CONCLUSION: Pre-operative plasma MMP-8 levels are related to the size of emboli from plaques during carotid endovascular intervention. Further in vivo studies need to be performed to assess the importance of this finding. There is potential for development of plasma markers to identify those patients at greater risk of embolic stroke during carotid endoluminal intervention.     

Safety of transfer,type of procedure,and factors predictive of limb salvage in a modern series of acute limb ischemia

Objective

The primary objective was to evaluate the safety of transfer, type of procedure, and factors associated with limb salvage in patients with acute limb ischemia (ALI) treated at a quaternary referral center.

Revascularization of the superior mesenteric artery alone for treatment of intestinal ischemia

OBJECTIVE: Complete revascularization is recommended by many authors for treatment of intestinal ischemia. The observation that postprandial intestinal hyperemia is limited to the superior mesenteric artery (SMA) has suggested to us that SMA revascularization alone should be adequate treatment. We preferentially manage intestinal ischemia with a single bypass graft to the SMA and herein update our results using this approach. METHODS: Patients were identified from a prospectively established vascular surgical registry. Each patient was assessed for acute versus chronic intestinal ischemia, preoperative angiographic findings, operation used, perioperative morbidity and mortality, late symptomatic relief, cause of death, and life table-determined survival and graft patency. Graft patency was determined by follow-up angiography or duplex scanning. RESULTS: Fifty bypass grafts to the SMA alone were performed in 49 patients (31 women, 18 men; mean age, 62 years) for treatment of intestinal ischemia. In all patients additional splanchnic arteries were available for bypass grafting. Operative indications were acute symptoms in 21 patients, 14 of whom had bowel infarction; chronic symptoms in 26 patients; and prophylaxis in conjunction with infrarenal aortic surgery in 3 patients. Thirty-two grafts originated from the aorta or an iliac artery, and 18 originated from an aortic graft. There were 40 prosthetic and 10 autogenous conduits. Perioperative mortality was 3% in patients with chronic symptoms and 12% overall. All survivors were symptomatically improved. Mean follow-up was 44 months. Nine-year assisted primary graft patency was 79%, and 5-year patient survival was 61%. Two late deaths occurred in patients with recurrent intestinal ischemia resulting from graft occlusions. CONCLUSIONS: Bypass grafting to the SMA alone appears to be both an effective and durable procedure for treatment of intestinal ischemia. Our results appear equal to those reported for "complete" revascularization for intestinal ischemia. When the SMA is a suitable recipient vessel, multiple bypass grafts to other splanchnic vessels are unnecessary in the treatment of intestinal ischemia.     

105例急怀肢体动脉阻塞的临床治疗分析

作者总结１９８２年３月－１９９６年９月收治的１０５例急性肢体动脉阻患者的临床诊断一治疗体会。对因栓塞与血栓形成两种不同原因患者的治疗结果进行比较。栓塞组肢体救治率８６．８％,高于血栓形成组５７．９％;而血栓形成组死亡率８％,低于栓塞组１５．７％。结果表明,两种不同病因所致生肢体动脉阻塞发病不同导致肢体救治率和死亡率有很大区别。     

Carotid angioplasty in a pulsatile flow model: factors affecting embolic potential.

OBJECTIVES: Carotid endoluminal intervention is an alternative to surgery but carries a risk of embolic stroke even with distal protection devices. We investigated the clinical features and degree of stenosis related to number and size of emboli during carotid angioplasty. DESIGN: An experimental ex vivo study. MATERIALS: An ex vivo pulsatile flow model was used in which temperature, velocity, flow, pressure and viscosity characteristics were designed to simulate the carotid circulation. METHODS: Carotid endarterectomy specimens excised as intact cylinders (n = 28) were subjected to a standardised angioplasty procedure using radiological guidance. Emboli collected in filters placed distally were counted and sized using microscopy. RESULTS: Median number of emboli during angioplasty was 133 (range 15-1331). Median size of the largest embolus was 700 microns (range 75-2400). Severity of stenosis correlated with increased maximum size (r = 0.55, p = 0.012). Statin therapy >4 weeks pre-operatively was associated with reduced emboli number and size (54 (range 15-748) vs 247 (range 37-1331) [p = 0.023] and 400 microm (range 75-2400) vs 1300 microm (range 600-2200) [p = 0.022]). CONCLUSIONS: In this model a wide range of emboli number and size were produced. Number and size of embolic particles were highest in patients with high-grade stenoses not receiving statin therapy.