Recurrent Occlusion Research Articles

Management of recurrent cerebral arterial occlusion in a patient with cardiac decompensation

We describe a woman with congestive heart failure who presented with acute cardiac decompensation followed by ischemic stroke. The management of the patient posed unique challenges for thrombolytic treatment (due to existing coagulopathy) and subsequent optimization of hemodynamic status. Issues related to rethrombosis and use of platelet glycoprotein IIB/IIIA inhibitors are also discussed.

Resistenz gegen Azetylsalizylsäure und Clopidogrel

Resistance to acetylsalicylic acid (ASA) or clopidogrel is understood from the clinical point of view as failure of the drugs to prevent recurrent vascular occlusions. Non-response to ASA and clopidogrel is defined from the laboratory aspect as an inability to cause in vitro detectable platelet function inhibition. It would be beneficial to monitor non-response to ASA or clopidogrel with platelet function methods, which detect the specific effect of these drugs, and thus prevent clinical events caused by failure of therapy. Non-response to ASA and clopidogrel are detected with different platelet function methods, which are not always clinically standardized and are assessing only the global platelet function and not the specific drug effect. Although various studies reporting 5 to 59% non-response for both drugs, support a clinical relevance of ASA and clopidogrel non-response, well-designed clinical prospective trials are required to identify patients with antiplatelet drug resistance. Furthermore, mechanisms explaining this phenomenon of drug resistance are still unknown.

Chronic mesenteric ischemia: Treatment of recurrent disease

A 42-year-old man with history of transaortic endarterectomies of the celiac and superior mesenteric arteries for chronic mesenteric ischemia (CMI) and a descending thoracic aorta-to-left external iliac artery bypass for Leriche-type symptoms, presented to our clinic after emergency laparotomy for gangrenous small bowel 5 years after the primary operation. He reported postprandial abdominal pain and recurrent weight loss. Angiography showed recurrent occlusion of the celiac, superior, and inferior mesentericarteries.Thepatentaorto-leftexternaliliacgraft(A)suppliedmostofhis mesenteric blood flow through the left hypogastric artery (B). Because the native aorta was diseased, the aorto-left external iliac bypass was used as an inflow source for a bypass to the patent distal superior and inferior mesenteric arteries using a bifurcated polytetrafluoroethylene graft (Cover). The limb to the superior mesenteric artery was configured in a gentle, retrograde loop configuration (C, large arrow). The limb to the inferior mesenteric artery was short, straight, and antegrade (C, small arrow). A palpable pulse was appreciated distally in both the superior and inferior mesenteric arteries after the anastomoses were complete. Before discharge he complained of mild abdominal pain after eating. Angiography confirmed patency of the prosthetic bypass (C). The abdominal pain resolved without further treatment. At 2-year follow-up, he was asymptomatic, had gained 15 pounds, and had quit smoking. Recurrent CMI is a rare condition occurring in approximately 17% of patients. 1 Recurrence is more common in younger patients and those who present at follow-up with significant weight loss. Mean number of vessels revascularized is usually significantly less in those patients who have recurrent chronic ischemia. Postoperative mortality is high in patients with recurrent acute visceral ischemia (85% vs 7% in CMI). Patients with recurrent CMI present a treatment dilemma. Reoperation with the same technique may not provide long-term relief and may be technically challenging. Choosing a secondary procedure complementary to the original surgery (visceral bypass after transaortic endarterectomy, or vice versa) affords patients the best chance for long-term relief of symptoms. 1

Cirugía de salvamento de extremidad: El cirujano vascular versus la amputación mayor

Este trabajo prospectivo muestra cómo entre marzo de 2001 y mayo de 2004 se manejaron siete pacientes que consultaron al Hospital de San José y la Clínica Fundadores en la Ciudad de Bogotá, Colombia, con lesiones isquémicas en el pie secundarias a oclusión aterosclerótica de las arterias infrapoplíteas. Dos de ellos cursaron con insuficiencia renal crónica, cuatro eran diabéticos y uno fumador durante varios años. El examen físico reveló lesiones isquémicas localizadas en el pie y pulso poplíteo adecuado con ausencia de pedio y tibial posterior. A todos se les realizó estudio arteriográfico mediante técnica de Seldinger, en el cual se confirmó oclusión de las arterias infrapoplíteas. Todos fueron llevados a exploración quirúrgica bajo anestesia regional, encontrando en cuatro de ellos buen lecho receptor a nivel de la arteria pedia, por lo que se les realizó injerto poplíteo-pedio con safena invertida, y en los tres restantes buen lecho a nivel de la arteria tibial posterior, por lo que se les practicó injerto poplíteo-tibial también con safena invertida. Después se procedió a desbridamiento de las áreas necrosadas. El seguimiento postoperatorio mostró que en los pacientes a los que se realizó injerto poplíteo-tibial hubo fracaso de los mismos, dos por infección del injerto y otro por oclusión recurrente. En ninguno de ellos se logró cicatrización de las lesiones del pie y por último uno requirió amputación infracondílea y dos supracondílea. En aquellos en los que se revascularizó la arteria pedia, se apreció permeabilidad adecuada del injerto con una cicatrización total de las áreas desbridadas al cabo de 90 días con recuperación de la marcha y funcionalidad total de la extremidad. Se concluye que en estos enfermos se debe siempre intentar algún procedimiento de revascularización y es la exploración quirúrgica la que en últimas define esta posibilidad, que si bien no siempre es efectiva, permite evitar amputaciones mayores en un número importante de casos, lo que se traduce en menor incapacidad laboral y mejor calidad de vida.

Can low molecular weight heparin replace unfractionated heparin during peripheral arterial reconstruction? An open label prospective randomized controlled trial

Objective This study was undertaken to evaluate the effect of low molecular weight heparin (LMWH) compared with unfractionated heparin (UFH) on the rate of occlusion and bleeding during peripheral vascular surgery. Methods The study was an open label, prospective, randomized trial, carried out by 20 Swedish surgical and vascular surgical departments that report to the Swedish Vascular Registry (SWEDVASC). Study subjects included patients undergoing peripheral vascular procedures, except carotid surgery. Of the 849 patients included, 817 were followed up to 30 days. LMWH (40 mg of enoxaparin) or UFH (5000 IU heparin) was given intravenously immediately before clamping. The same formulation in diluted form was used for vascular rinsing. Main outcome measures included patent reconstruction at day 1, perioperative blood loss, and the percentage of patients requiring protamin. Further, 30-day data for mortality, repeat operation, and recurrent occlusion are reported. Results The mortality rate at 30 days was 2.7%, with no difference between groups. The patency rate at 1 day was 91.2% to 98.4%, depending on diagnosis and type of reconstruction. No difference was recorded between study groups (0.6 < P < 1.0). At 30 days the patency rate was 83.1% to 100% (0.2 < P < .9). Median blood loss was 350 mL (interquartile range [IQR], 200-800 mL) in the LMWH group and 425 mL (IQR, 200-900 mL) in the UFH group ( P = .02). Protamin was given to significantly fewer patients in the LMWH group ( P = .001). LMWH was comparable to UFH during peripheral vascular reconstruction in terms of 1-day and 30-day graft patency, operative blood loss, and hemorrhagic complications. Protamine was required less often after LMWH. In this randomized trial LMWH was as effective as UFH in preventing thrombosis without excess bleeding or hemorrhagic complications.

Recurrent Peripheral Arterial Occlusion in Acute Promyelocytic Leukemia

Recurrent Peripheral Arterial Occlusion in Acute Promyelocytic Leukemia

High Dose Rate Brachytherapy for Nonmalignant Airway Obstruction: New Treatment Option

High dose rate (HDR) endobronchial brachytherapy is widely used as a palliative treatment for symptomatic airway obstruction by primary or secondary malignant tumors. We report on a successful use of HDR brachytherapy in patients with nonmalignant airway obstruction. Case series Six patients received HDR brachytherapy for airway obstruction caused by granulation tissue around a metal stent placed for restoration of the airway patency for nonmalignant causes. In four patients, brachytherapy was performed following recurrent occlusion of the airway by granulation tissue formation; in two patients, it was done as a prophylactic procedure. HDR brachytherapy catheters were passed through the metal stents under direct fluoroscopic guidance. Simulation and computerized treatment planning were done, and a single dose of 10 Gy was administered using a brachytherapy remote afterloader with a (192)Ir source. The dose was prescribed to a distance of 1 cm from the center of the source, with a margin of 1 cm from the proximal and distal ends of the stent. At a median follow-up of 15 months, moderate granulation tissue formation was observed in only one patient; in four others, it was categorized as minimal, 5 to 30 months from the procedure. Restoration of the lumen was complete in four patients, near complete in one patient, and partial in one patient. In one patient, previously treated by external radiotherapy, local tissue necrosis was evident. HDR brachytherapy can be used safely for nonmalignant airway obstruction. Further studies including more patients and longer follow-up are needed.

Phospholipid Autoantibodies and the Antiphospholipid Antibody Syndrome: Diagnostic Accuracy of 23 Methods Studied by Variation in ROC Curves with Number of Clinical Manifestations

We analyzed the diagnostic accuracies for the diagnosis of antiphospholipid syndrome (APS) of 23 antiphospholipid antibody (APL-Ab) assays targeted at different antigen preparations and immunoglobulin isotypes. In 144 patients with suspected APS, anti-cardiolipin (aCL) and anti-beta2-glycoprotein I (abeta2GPI) antibodies were measured with 23 different ELISAs from three manufacturers. Data were analyzed by ROC curves. In the absence of an accepted criterion standard, the endpoint "diagnosis of APS" was varied according to the number (two through five) of signs and symptoms of APS. Although the presence of lupus anticoagulant was associated significantly with APL-Ab in 10 of 23 assays (P = 0.01-10(-4)) and recurrent arterial or venous occlusions were significantly associated with APL-Ab of IgM isotype in 5 of 6 assays (P = 0.02-10(-4)), sensitivity for detection of APS did not exceed 67%. With the exception of IgA APL-Ab, the diagnostic accuracy of the assays improved when the diagnosis of APS was based on an increasing number of simultaneous features of APS. For most methods, areas under the ROC curves were >0.8 irrespective of the method's subclass specificity and antigen preparation (aCL or abeta2GPI), if the clinical diagnosis of APS was based on four or more signs and symptoms of APS. Despite considerable heterogeneity in the individual test results, a single test of IgG or IgM isotype targeted at either aCL or abeta2GPI antibodies has excellent diagnostic accuracy when the criterion for diagnosis requires four or more typical manifestations of APS.

Femoropopliteal arteries: immediate and long-term results with a Dacron-covered stent-graft.

To assess immediate and long-term outcome after femoropopliteal implantation of a Dacron-covered stent-graft in patients with peripheral arterial disease. This prospective cohort study included 30 consecutive patients who underwent Dacron-covered stent-graft implantation because of recurrent stenosis after percutaneous transluminal angioplasty in the femoropopliteal segment. After interventional treatment, 100 mg of acetylsalicylic acid daily and oral anticoagulation therapy (therapeutic level, international normalized ratio, 2.0-3.0) were administered. Patients were followed up with ankle-brachial index measurement, color-coded duplex ultrasonography, and angiography. Primary and secondary patency rates and postintervention complications were documented as was initial technical success. Kaplan-Meier and life table analyses were used for calculation of patency rates. Initial technical success was achieved in all 30 patients, with significant improvement of ankle-brachial index from a preintervention mean of 0.5 +/- 0.14 (SD) to a postintervention mean of 0.8 +/- 0.17 (P <.001). Postimplantation noninfectious fever and leukocyte and C-reactive protein level elevation occurred in 12 patients (40%), and 17 patients (57%) reported persistent pain at the site of implantation for a mean of 5 days (range, 2-28 days). Early recurrent occlusion within the first 24 hours was found in five patients (17%). Within the mean follow-up period of 60 months +/- 10, restenosis occurred in 25 patients (83%). At 6, 12, 36, and 72 months, respectively, primary patency rates were 27%, 23%, 17%, 17%, and secondary patency rates were 63%, 60%, 34%, 34%. Implantation of Dacron-covered stent-grafts for treatment of femoropopliteal lesions leads to high early and late restenosis rates, with a considerable rate of complications, such as fever and pain.

Radiologic after-care of transjugular intrahepatic stent shunt (TIPSS)]

The transjugular intrahepatic stent-shunt (TIPSS) is a well accepted minimal invasive therapy for complications of portal hypertension: recurrent variceal bleeding, refractory ascites and liver failure due to the Budd-Chiari syndrome. The high frequency of shunt stenoses and occlusions makes regular follow up examinations essential. Despite modern non invasive imaging methods direct portography still is the gold standard for shunt surveillance in TIPSS. Ultrasound is helpful to detect shunt dysfunction, but nevertheless its failure rate is considerable despite the use of contrast enhancers such as Levovist because of anatomic and physical limitations, particularly when TIPSS-tracts deep in the liver are present. Reintervention rates approach 90-100% after 24 months, with 100% in child's A patients with comparatively good liver function. However, a strict shunt surveillance program with early portography and reintervention when necessary guarantees high clinical success rates associated with very low rebleeding rates below 10%. Overall the secondary success rate is 80%. Secondary failures are mainly caused by lack of patient compliance during follow-up. In a subgroup of patients no shunt maturation is observed, requiring multiple shunt revisions. In cases of recurrent shunt occlusions an association with bile leaks is presumed. In selected cases patients with chronically recurrent shunt stenosis or occlusions may benefit from placement of TIPSS stent grafts.

Atheromatous plaque formation and thrombogenesis: formation, risk factors and therapeutic approaches

Angiographic and ultrasound analyses of the coronary arteries have confirmed the importance of acute thrombosis as the primary cause of myocardial infarction and acute coronary syndromes. Intravenous treatments aimed at recanalizing the obstructed arteries can help achieve acute reperfusion of the organ, but often a thrombus-triggering plaque remains active for some time. It is not yet known how long a plaque remains active, but it has been shown that systemic markers of coagulation remain elevated as long as 6 months after the event. The presence of a residual mural thrombus overlying an active plaque predisposes to recurrent thrombosic vessel occlusion. A fragmented thrombus appears to be one of the most powerful thrombogenic substrates, and residual thrombus may predispose to recurrent thrombosis. Non-acute, chronic antithrombotic treatments and pharmacological interventions should aim to block thrombosis and preserve vascular prostacyclin formation. Experimental work has shown that both aspirin and triflusal inhibit the growth of a thrombus on a fresh mural thrombus to the same extent, but triflusal was found to preserve cyclooxygenase-2 activity in the vessel wall. Research to uncover the mechanism of action of triflusal at the vascular level is in progress.

The role of cytokines in sickle cell disease.

Sickle cell disease (SCD) is characterized by chronic hemolysis, frequent infections, and recurrent occlusions of microcirculation, which cause painful crises and result in chronic organ damage and failure. Occlusions of the microcirculation and infections are important factors that stimulate the production of cytokines and acute-phase proteins. Cytokines seem to be involved with several possible mechanisms in the pathogenesis of vasoocclusive phenomena in SCD: vascular endothelial activation, induction of red-cell adhesiveness to vascular endothelium, induction of neutrophil adhesiveness to endothelium, development of vascular intimal hyperplasia, platelet activation, endothelin-1 production, and dysregulation of endothelial apoptosis. Cytokines are also thought to be involved in the regulation of hemopoiesis, the inhibition of immune functions, and the development of growth deficits. Investigation of cytokines in SCD patients will elucidate the pathogenesis of the disease and its complications and may help in assessing disease severity and prognosis.

Recurrent Abrupt Occlusion after Transluminal Angioplasty for Basilar Artery Stenosis: Case Report

Recurrent Abrupt Occlusion after Transluminal Angioplasty for Basilar Artery Stenosis: Case Report

Laparoscopic salvage of malfunctioning peritoneal catheters.

Malfunction of peritoneal catheters due to mechanical outflow problems is an annoying complication in patients undergoing chronic peritoneal dialysis (PD). Correction often involves catheter replacement or revision via laparotomy. Twenty-five patients undergoing PD who developed mechanical catheter flow restriction underwent 28 laparoscopic procedures. Preoperative diagnoses were made by contrast catheter radiography and were: catheter sequestration (36%), omental wrap (64%). Pneumoperitoneum was induced after general anesthesia and laparoscopy was performed using a Storz laparoscope. The catheter was then identified and manipulation was attempted using instruments placed percutaneously. In 26 cases (93%), the catheter was freed and function restored. In two cases (7%), adhesions were so numerous and dense that the distal catheter could not be visualized. Four episodes of peritonitis developed subcutaneous leakage of peritoneal fluid which responded to cessation of PD for 2 weeks. Four patients had recurrent occlusions; three of these were managed laparoscopically. Two patients developed late hernias at the site of insertion of the laparoscope. Catheter patency averaged 9.2 months postoperatively. Laparoscopic revision is a successful technique for salvage of occluded peritoneal catheters.

Endoscopic biliary stenting: Plastic stent or expandable metallic stent?

Since its introduction 1979, endoscopic biliary stenting has become the method of first choice to treat cholestasis in malignant or benign biliary obstuction or leakage of biliary fistulas. The success rate of endoscopic biliary stenting generally exceeds 90% and procedure-related complications are rare. Although metal stents are becoming more popular, plastic stents are still the first choice. Their major drawback is occlusion with sludge mediated by bacteria. Pharmaco-chemical measures failed to prevent occlusion. With Teflon material and a 10-French stent, stent exchange rates were reduced to 15% in patients with malignant biliary obstruction, the shape without sideholes showing the best results. Stent exchange is easily feasable. Metal stents are expensive and more difficult to handle. Occlusion with sludge is rare, but patency is limited by tumor ingrowth. Metal stents may be indicated in selected patients, such as those with recurrent stent occlusion causing cholangitis. If only a small-caliber prosthesis (7-Fr) can be placed (e.g. in Klatskin tumor) metal stents may have a longer patency than plastic stents. Metal stents should not be used in benign biliary obstruction because these stents are not removable.

Application of axillo-bifemoral bypass combined with intraoperative stent-optimized angioplasty of subclavian artery in a high-risk patient with recurrent occlusions following aorto-iliac vascular reconstructions

Application of axillo-bifemoral bypass combined with intraoperative stent-optimized angioplasty of subclavian artery in a high-risk patient with recurrent occlusions following aorto-iliac vascular reconstructions

Failure of thrombin inhibition to prevent intracoronary thrombosis in the dog.

1. Recurrent occlusion after thrombolysis may be caused by thrombin receptor-mediated platelet thrombosis occurring in a residual stenosis. To test the relative importance of the platelet thrombin receptor under conditions of high shear and endothelial damage (the Folts model of intracoronary thrombosis) we used the specific thrombin inhibitor recombinant hirudin. 2. A critical coronary artery stenosis overlying an area of crushed endothelium was used in a repeated measures study of eight open-chest anaesthetized dogs. In the control period, recurrent thrombosis occurred at an average rate (+/- SD) of 4.4 +/- 1.4 ml/min2. Infusion of recombinant hirudin at 1.6 mg h-1 kg-1 abolished recurrent thrombosis in three dogs, but the thrombosis rate averaged 4.7 +/- 2.9 ml/min2 in the remaining five animals. 3. Haematological measurements demonstrated the activity of recombinant hirudin: thrombin time rose from 13 +/- 3 s to > 165 s universally (P < 0.01), partial thromboplastin time rose from 14 +/- 2 s to 29 +/- 10 s (P < 0.01). Bleeding time rose from 2.3 +/- 0.8 min to 4.7 +/- 1.8 min (P < 0.05). 4. It is concluded that specific thrombin inhibition, despite affecting coagulation, is relatively ineffective in preventing intracoronary thrombosis under conditions of high shear.

Editorial: Oxygen radical scavengers as adjuvant therapy for coronary reperfusion

The cornerstone of modern reperfusion therapy is the well-established experimental and clinical observation that timely and sustained restoration of blood flow can limit myocardial infarct size, enhance the long-term recovery of left ventricular function, and improve survival post-infarction [1,2]. Reperfusion has, however, been termed a double-edged sword [3], due in large part to the potentially deleterious burst of cytotoxic oxygen-derived free radicals--most notably the superoxide anion, hydroxyl radical, and their intermediary, hydrogen peroxide--documented to occur upon restoration of blood flow to previously ischemic tissue [4-6]. Indeed, overwhelming attention has focused on the role of these reactive oxygen species in precipitating so-called lethal reperfusion injury (i.e., the death of previously ischemic but viable myocytes by reperfusion per se), a concept that, despite intensive investigation, remains unsubstantiated [7-9]. Oxygen radicals may, however, confound the benefits of early reperfusion by a second means, by triggering platelet aggregation [10] and thereby contributing to acute reocclusion following initially successful thrombolysis [2,11,12]. In contrast to the uncertainties surrounding lethal reperfusion injury, the incidence and dire consequences of recurrent occlusion are clear. For example, recent analysis of data from the Primary Angioplasty in Myocardial Infarction (PAMI) trial revealed a significant increase in the rate of death or reinfarction, a greater need for further interventional procedures, and prolonged hospitalization in the 28% of patients initially reperfused with recombinant tissue-type plasminogen activator (rtPA) who subsequently developed recurrent ischemia [12]. This editorial focuses on this second and less well-appreciated facet of free radical production in the setting of ischemia/reperfusion, and asks the question, Does adjuvant therapy with oxygen radical scavenging agents offer a promising therapeutic strategy to maintain vessel patency and maximize the benefits of early reperfusion? The Premise: Oxygen Radicals Trigger Platelet Aggregation

Functional and ultrastructural alterations of canine myocardium subjected to very brief coronary occlusions.

The effects of very brief and recurrent coronary occlusions on myocardial regional shortening and its ultrastructure have been analysed. Ultrasonic crystals were implanted in the left ventricular subendocardium of 23 anaesthetized dogs with the thorax open, to measure the shortening fractions of an ischaemic and a control segment. Twenty 2 min total occlusions were provoked in the left anterior descending coronary artery, with 3 min recovery intervals (reperfusion) between occlusions. The shortening fraction decreased progressively with each occlusion, reaching a value 18.9% lower than the basal after the last ischaemic episode (P < 0.05); 32.3% after 4 h of reperfusion (P < 0.01), and 28.6% after 24 h (P < 0.01). Qualitative and quantitative ultrastructural analysis showed an increase in the mitochondrial volume of the ischaemic tissue (158% vs control, P < 0.001) with significant damage to the cell components (7.7-fold increases vs control mitochondria). These results show that when the myocardium is subjected to very brief and repeated coronary occlusions, there is progressive deterioration of systolic function with structural alterations, mainly at the mitochondrial level. These modifications are still observable 24 h after the end of ischaemic stimulation and could be the cause of transitory and/or chronic systolic dysfunctions in the absence of previous heart attack.

Endoscopic application of new membrane covered self-expandable biliary metal stent (Covered modified-giantruco biliary stent)

ENDOSCOPIC APPLICATION OF NEW MEMBRANE COVERED SELF-EXPANDABLE BILIARY METAL STENT (COVERED MODIFIED-GIANTRUCO BILIARY STENT) CS Shim, DW Song, CW Park, JS Lee, MS Lee, SW Cho. Division of Gastroenterology, Department of Internal Medicine, Soon Chun Hyang University,. Seoul, Korea Many kind of biliary stents have been used to maintain patency of a bile duct which is obstructed due to benign stricture~ or tumors. However, the biliary stents in current use have a tendency to block. The long-torm functioning of biliary stents is limited by clogging. In order to maintain Iong-term-stent patency, a larger diameter of biliary stents is needed and expandable metal stents have been developed. But the limitations of these expandable metal stents are non-removability, ingrowth and overgrowth of the tumor. Indeed, tumor may grow through the spaces between the wires and recurrence of occlusion by ingrowth of the tumors was frequently observed in patients with malignant obstruction. To overcome these limitations, we developed new membrane covered self-expandable metal stent (covered modified-Giantruco biliary stent) with polytetrafluoro -ethylene (PTFE) which used to artificial vessel. This stent has more advantages; applied stent is removable and tumor ingrowth is protected. We applied this new stent (10 cm in length) endoscopically to 66 year-old female with malignant biliary obstruction (distal CBD cancer). This covered stent was compressed into 14 Fr. polyethylene introducer (180 cm in length), and advanced via transpapillary route by motherscope (TJFM20) with large working channel (5.5 mm in diameter) using 12 Fr. pusher catheter. We expect this stent has long-term patency and adequacy of biliary drainage, but we cann't evaluate disadvantage of this stent until now due to short-term follow up.