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At least 55 records · Page 3Linked to original sources
PubMed2007

Pretreatment ipsilateral regional cortical blood flow influences vessel recanalization in intra-arterial thrombolysis for MCA occlusion.

BACKGROUND AND PURPOSE: The aim of acute stroke interventions is to achieve recanalization of the target occluded artery. We sought to determine whether pretreatment cortical cerebral blood flow (CBF) was associated with vessel recanalization in patients undergoing intra-arterial therapy. METHODS: This is a retrospective analysis of patients who underwent a quantitative xenon CT blood flow study and were noted to have a documented M1 middle cerebral artery (MCA) or carotid terminus occlusion less than 6 hours from symptom onset between January 1997 and April 2001. Twenty-three patients who underwent intra-arterial thrombolysis were included in the analysis. Univariate and multivariate analyses were performed to determine whether pretherapy CBF was correlated to the likelihood of recanalization. RESULTS: A total of 23 patients were studied in this analysis with a median age of 69 (range 32-81) and median National Institutes of Health Stroke Score of 19 (range, 8-22). Twelve patients (52%) underwent combined intravenous/intra-arterial therapy, and 11 patients (48%) were treated with intra-arterial thrombolytics alone. Successful vessel recanalization (Thrombolysis in Myocardial Infarction classification 2 or 3 flow) occurred in 13 patients (57%). The only variable associated with recanalization in multivariate modeling was mean ipsilateral MCA CBF (odds ratio, 1.25; 95% confidence interval, 1.01-1.54; P = .035). A receiver operating characteristic curve was generated, and a mean ipsilateral MCA CBF threshold of 18 mL/100 g/min was found to be the threshold for successful recanalization. CONCLUSIONS: Our study suggests that patients with higher mean ipsilateral MCA CBF are more likely to recanalize. The threshold for successful revascularization may be 18 mL/100 g/min. Further study is required to determine whether pretreatment CBF is related to recanalization success.

Adult↗
PubMed1990

Laser recanalization in high risk patients.

Laser recanalization was attempted in 13 patients in whom the risk of surgical therapy was increased by severe angina, infection, absent venous conduit, or recent deep venous thrombosis, and in 4 patients at high risk for limb loss due to severe infrapopliteal arterial occlusive disease. Total occlusions of the superficial femoral, tibial, or peroneal arteries were treated. Recanalization was accomplished using Argon laser power and a Spectraprobe-PLR. Two patients also required common femoral artery endarterectomy to improve inflow. Laser recanalization was successful in 9 patients (53%), and 8 (47%) had relief symptoms. None of the 4 patients with tibial and peroneal artery occlusion had successful recanalization or limb salvage. Restenosis or reocclusion developed in 4 patients during the first year after successful recanalization, but only 1 had recurrent symptoms. Limb salvage was initially achieved in 5 of 8 recanalization failures by surgical reconstruction but 3 developed graft infections requiring graft removal in 2 and amputation in 1. Thus, laser recanalization can accomplish limb salvage in selected patients whose medical or surgical risks complicate arterial bypass surgery.

Adult↗
PubMed1992

In vitro laser recanalization of chronically occluded prosthetic grafts.

Polytetrafluoroethylene (PTFE) and Dacron grafts were implanted in canine femoral and carotid arteries using PTFE and Prolene suture, respectively. Arteries containing occluded grafts were explanted and laser recanalization was attempted in vitro. Laser recanalization was successful in 78% of PTFE grafts compared to 30% of Dacron grafts. Recanalization was complete (residual stenosis less than 5%) in opened PTFE grafts, whereas residual stenosis averaged 60% in recanalized Dacron grafts. PTFE graft/PTFE suture anastomotic tensile strength was unchanged after recanalization, while Dacron graft/Prolene suture anastomotic tensile strength decreased significantly. In addition, anastomotic bursting pressure was significantly higher for lased PTFE grafts with PTFE sutures (300 mg Hg) compared to lased Dacron grafts with Prolene sutures (70 mm Hg). Chronically occluded PTFE grafts with PTFE suture can be safely and effectively opened by laser recanalization. In contrast, attempted laser recanalization of Dacron grafts sutured with Prolene suture is seldom successful, significantly weakens the graft artery anastomosis, and should be avoided.

Anastomosis, Surgical↗
PubMed1982

Percutaneous transluminal coronary artery recanalization in evolving myocardial infarction.

A brief description of recanalization of the thrombotic coronary artery is provided, including the historical background and our own first experience of recanalization during the event of an acute catheter complication. Mechanical recanalization of occluded coronary arteries as initially performed by us is described. The subsequent use of intracoronary infusion of streptokinase is also detailed. An account is given of the angiographic and clinical results in a study of 59 patients. We then consider the encountered and potential complications of percutaneous transluminal coronary artery recanalization (PTCR) based on a study of 232 acute infarction patients treated in four different centers. A discussion of the potential benefits of the intervention is provided, including lower mortality in a patient subgroup that underwent successful recanalization, as well as improved left ventricular function as seen angiographically in successfully recanalized patients. Use of intracoronary thallium injections before and after recanalization is discussed. It is stated that precise delineation of efforts will require randomized control trials. Finally, we provide some suggestions as to the potential follow-up treatment and future development of the technique.

Angioplasty, Balloon↗
PubMed2002

Local intra-arterial thrombolysis in the carotid territory: does recanalization depend on the thromboembolus type?

Little is known about whether recanalization of carotid territory occlusions by local intra-arterial thrombolysis (LIT) depends on the type of the occluding thromboembolus. We retrospectively analysed the records of 62 patients with thromboembolic occlusions of the intracranial internal carotid artery (ICA) bifurcation or the middle cerebral artery who were undergoing LIT with urokinase within 6 h of symptom onset. We determined the influence of thromboembolus type (according to the TOAST criteria), thromboembolus location, leptomeningeal collaterals, time interval from onset of symptoms to onset of thrombolysis, and patient's age on recanalization. The thromboembolus type was atherosclerotic in six patients, cardioembolic in 29, of other determined etiology in four, and of undetermined etiology in 23 patients. Thirty-three (53%) thromboembolic occlusions were recanalized. The thromboembolus location but not the TOAST stroke type nor other parameters affected recanalization. In the TOAST group of patients with cardioembolic occlusions recanalization occurred significantly less frequently when transoesophageal echocardiography showed cardiac thrombus. The present study underlines the thromboembolus location as being the most important parameter affecting recanalization. The fact that thromboembolic occlusions originating from cardiac thrombi had a lower likelihood of being resolved by thrombolysis indicates the thromboembolus type as another parameter affecting recanalization.

Carotid Artery Thrombosis↗
PubMed2006

Recanalization after endovascular treatment of intracerebral aneurysms.

INTRODUCTION: The aim of this study was to evaluate the risks of endovascular therapy, aneurysm regrowth, recanalization and the need for reembolization. METHOD: A prospective analysis was performed on 211 aneurysms treated endovascularly from February 2000 to December 2003. Of these 211 aneurysms, 81 were asymptomatic and 130 were ruptured. The risks of endovascular therapy, aneurysm regrowth, recanalization and the need for reembolization were evaluated. RESULTS: The mean observation time was 10 months (ranging from 178 to 830 days). Complete occlusion (100%) in the initial intervention was achieved in 171 of 201 aneurysms (85%), 80-95% occlusion in 24 aneurysms (12%), and <80% occlusion in 6 aneurysms (3%). Recanalization had occurred at the first follow-up in 34 of all 153 aneurysms reassessed (22.2%). Of 133 aneurysms with initial 100% occlusion, 107 (80.4%) remained completely occluded, 17 (12.7%) showed recanalization, and 9 (6.7%) showed neck regrowth. Among those with 80-95% occlusion, 20 were reassessed, and of these 2 showed spontaneous occlusion, 10 (50%) still showed the initial neck, and 8 (40%) showed increased recanalization. One aneurysm which initially showed <80% occlusion remained unchanged, and another showed showed recanalization. Of the 153 aneurysms, 12 (7.8%) were recoiled, 2 initially <80% occluded, 7 initially 80-95% occluded and 3 initially totally occluded. CONCLUSION: In spite of low morbidity and mortality, one in four aneurysms will show recurrence. The initial degree of occlusion seems to have an influence on the likelihood of recanalization.

Aneurysm, Ruptured↗
PubMedDate not supplied

Percutaneous recanalization of acute internal carotid artery occlusions in patients with severe stroke.

BACKGROUND: Sudden symptomatic occlusions of the proximal internal carotid artery (ICA) resulting in severe middle cerebral artery (MCA) ischemia and stroke are usually not accessible by rt-PA thrombolysis and the prognosis is usually very poor. Mechanical recanalization of the proximal ICA combined with intravenous and intra-arterial thrombolysis was therefore used as a rescue procedure. METHODS: Ten patients (9 men, 1 woman; mean age 56.1 years) were treated with emergency recanalization of the proximal carotid artery by using stents and/or balloon angioplasty as a rescue procedure. Three patients showed dissection, and 7 had atherothrombotic occlusions. Nine of 10 presented with an initial modified Rankin Scale (mRS) of 5, the remaining patient with mRS 4 (average NIHSS 21.4). After sonographic confirmation of ICA with associated MCA/distal ICA occlusion and bridging with rt-PA (without abciximab) an emergency angiography was performed with subsequent mechanical recanalization by percutaneous transluminal angioplasty (PTA) (n = 1) or primary stenting (n = 9) using self-expanding stents. Distal protection was used in 1 of 10 patients. RESULTS: Recanalization of the proximal ICA was achieved in all. At least partial recanalization of the intracerebral arteries was achieved in all, and complete recanalization in 5. In 4 of 10 patients limited hemorrhage was detected during CT controls. Major complications included 2 patients who had to undergo hemicraniectomy. One patient died from malignant infarction. At the time of discharge from the stroke unit 9 of 10 patients had improved markedly, 5 patients having an mRS of < or =2, and 3 patients a mRS of 3. At control after a mean of 20 weeks, 7 of 8 (88%) patients had a mRS < or =2, and 1 a mRS of 3. CONCLUSIONS: Primary mechanical recanalization of ICA occlusions by stent and PTA combined with fibrinolysis and/or GPIIb/IIIa-receptor antagonists seems to be feasible to improve patient outcome significantly.

Acute Disease↗
PubMed2004

Bovine pericardium buttress limits recanalization of the uncut Roux-en-Y in a porcine model.

In contrast to the traditional Roux-en-Y reconstruction, an uncut Roux-en-Y provides biliopancreatic diversion and may preserve myoelectric continuity. Previous iterations of the uncut Roux have been plagued by recanalization of the uncut staple line in the afferent small bowel. Our aim was to determine if bovine pericardium buttress prevents recanalization of the stapled small bowel partition in a porcine model. Sixteen female pigs ( approximately 30 kg) underwent a side-to-side stapled jejunojejunostomy, 20 cm distal to the ligament of Treitz, with placement of a nondivided stapled partition with a single row of 2.5 mm width staples in the intervening jejunal loop. Nine animals in the experimental group had a bovine pericardium buttressed staple line (5 permanent, 4 absorbable), whereas seven animals in the control group had a nonbuttressed staple line. At 6 or 12 weeks, necropsy was performed and the primary outcome, staple line recanalization, was assessed grossly and histologically. Statistical analysis was performed by means of the chi-square test. There were no major complications and all animals gained weight. Overall, eight of nine bovine pericardium buttressed staple lines were grossly and histologically intact at necropsy, whereas all nonbuttressed uncut staple lines had recanalized completely (P<0.05). At 6 weeks, both permanent (N=4) and absorbable (N=3) buttress preparations prevented recanalization. At 12 weeks the permanent buttress remained closed (N=1), but the absorbable buttress had allowed partial recanalization (N=1). The use of bovine pericardium buttress will prevent small bowel recanalization of uncut small bowel staple lines at early follow-up. Pilot data at intermediate follow-up suggest permanent buttress is more durable than absorbable buttress. These results warrant investigation of bovine pericardium for intestinal applications in humans.

Anastomosis, Roux-en-Y↗
PubMed1996

Recanalization of obstructed fallopian tube by selective salpingography and transvaginal bougie dilatation: outcome and cost analysis.

OBJECTIVE: To investigate effectiveness and cost of transcervical salpingography and recanalization in the management of infertility caused by tubal occlusion. DESIGN: Retrospective analysis of patients investigated with transcervical selective salpingography and, in some instances, treated by transcervical recanalization. SETTING: Four hundred patients with hysterosalpingography diagnosis of obstructed fallopian tubes (clinical environment) are investigated. A repeat hysterosalpingogram after administration of a prostaglandin antagonist demonstrated patency of the tubes in 82 patients and selective transcervical salpingography demonstrated patency in an additional 131 patients. INTERVENTION: Transcervical tubal recanalization. Of the remaining 187 patients, recanalization by transcervical technique was successful in 145 patients. The underlying etiology for tubal obstruction was salpingitis isthmica nodosa in 62, salpingitis and perisalpingitis in 71, endometriosis in 8, failed surgical anastomosis in 43, and undeterminate cause in 3 patients. Pregnancy was attained in 24 patients, there were 10 minor and 1 major complication. OUTCOME MEASURE: Attained and maintained patency of tubes, pregnancy, attendant complications. CONCLUSION: A pregnancy rate of 12.8% was attained after transcervical recanalization of obstructed tubes. An attendant increased rate of pregnancy in patients proven patent after selective salpingography, valuable detailed information about proximal and distal tubes after recanalization of the obstructed proximal tube segment, the low rate of complications, and low cost are factors recommending the use of this technique. Moreover, tubal surgery or IVF treatment are not influenced adversely by prior transcervical tubal recanalization and remain an option for patients who failed to attain pregnancy.

Adult↗
PubMed1998

Recanalization therapies for acute ischemic stroke.

Angiographic studies performed within 6 hours of stroke onset have demonstrated that 75-80% of patients with an acute ischemic stroke have an angiographically visible occlusion of an extracranial and/or intracranial artery that is the cause of the ischemic stroke. The NINDS t-PA Stroke Study demonstrated that recanalization of occluded brain arteries can successfully salvage ischemic brain if intravenous tissue plasminogen activator (t-PA) is initiated within 3 hours of stroke onset. The effectiveness and safety of intravenous t-PA beyond 3 hours has yet to be shown. Large clots in the internal carotid artery, vertebral or basilar artery, or middle cerebral artery trunk are infrequently lysed by intravenous t-PA during the first hour of treatment. Intraarterial delivery of a thrombolytic agent appears to lyse clots in cerebral arteries more effectively than intravenous t-PA. However, a head-to-head comparison of full-dose intravenous t-PA and intraarterial therapy has yet to be done, and recanalization rates reported in the intraarterial studies are at longer times after the start of therapy than the rates of recanalization reported in intravenous t-PA studies. Intraarterial delivery of thrombolytic therapy takes longer than intravenous delivery, and even intraarterial delivery takes 2 hours on average to partially or completely lyse 75% of clots. Intraarterial delivery of a thrombolytic agent has yet to be proven effective and safe in improving long-term outcome of ischemic stroke patients. The approach of combining intravenous and intraarterial delivery of t-PA or other pharmacologic agents is an attractive option that deserves further study. Mechanical lysis of clots, in combination with pharmacologic therapies, is a more effective way to recanalize coronary arteries and salvage heart muscle than intravenous thrombolytic therapy alone. This approach is likely to be effective in ischemic stroke as well. What is needed is advances in catheter technology that meet the special requirements of clot lysis in cerebral vessels. Whether neuroprotective agents can extend the therapeutic window for effective clot lysis and recanalization remains to be seen. Thrombolytic therapy and other pharmacologic treatments of clot in cerebral vessels will likely remain a two-edged sword. Pharmacologic therapies that increase the likelihood of clot lysis and recanalization, such as thrombolytic agents, the platelet GIIbIIIa receptor blockers, defibrinogenating agents, and even the newer more potent thrombolytic agents, also concomitantly increase the risk of bleeding into the brain. What we will be searching for in the coming decade is the correct mechanical strategy, dose of a given pharmacologic agent, or combination of agents that maximizes recanalization and minimizes the risk of intracerebral hemorrhage.

Angioplasty, Balloon↗
PubMed1992

[Recanalization of occluded coronary arteries using the Magnum system].

Recanalization procedures with the "Magnum" system were undertaken in 137 patients (113 men, 24 women; mean age 57.1 +/- 8.1 years) with complete occlusion of a coronary artery. The system consists of a 0.021 inch guidewire with a flexible 1 mm diameter olive tip, a double-lumen probing catheter and a Magnarail balloon catheter. Chronic coronary artery occlusion of maximally 3 months was present in 51 patients (37%), for over 3 months in 52 (38%), while the duration of occlusion was unknown in 18 (13%). An acute coronary occlusion was successfully recanalized in 7 patients (5%), while in 9 (7%) it was accomplished when it had occurred during or shortly after a percutaneous coronary artery angioplasty (PCTA). The occlusion was successfully passed in 87 patients (64%); in 15 of them recanalization with another system had failed. The highest success rates were obtained with an acute occlusion (5 of 7; 71%), occlusion of 3 months' duration or less (39 of 51; 76%), and occlusion during PTCA (8 of 9; 89%). The success rates were lower for occlusions over 3 months' duration (25 of 52; 48%; P < 0.05) and of unknown duration (10 of 18; 56%; n.s.). Recanalization after failed recanalization was successfully accomplished by rotation-angioplasty (n = 2) or a standard system (n = 4).--These results indicate that the Magnum system is suitable for recanalizing chronic or acute coronary occlusion. But cardiologists should be capable of using several systems to increase the chances of successful recanalization.

Adult↗
PubMed1989

Recanalization of total arterial occlusions with the Kensey dynamic angioplasty catheter.

The Kensey dynamic angioplasty catheter is a new device for recanalization of peripheral arterial occlusions. Twelve patients with segmental occlusions who were not considered candidates for conventional bypass surgery because of cardiovascular risk factors were studied. Four of the patients were treated in the operating room. Two had excellent primary results in limb salvage situations, and recanalization of an occluded femoropopliteal bypass graft was successful in another. Bilateral iliac recanalizations in the fourth patient were locally successful but did not prevent the patient's death from advanced ischemic disease. Eight patients were treated percutaneously. Initial recanalization was successful in seven. Four had early reocclusions and required amputation below the knee. One suffered distal embolization after recanalization of a 6-cm popliteal segment and underwent above-the-knee amputation. Long-term follow-up (7-18 months) in the other three patients with successful primary recanalizations has confirmed patency of the recanalized segments.

Angiography↗
PubMed2003

Regression of collateral function after recanalization of chronic total coronary occlusions: a serial assessment by intracoronary pressure and Doppler recordings.

BACKGROUND: Collaterals can maintain myocardial function or preserve viability in chronic total coronary occlusions (CTOs). It is unknown whether and to what extent collaterals regress after successful recanalization of a CTO. METHODS AND RESULTS: In 103 patients with successful recanalization of a CTO collateral function was assessed by intracoronary Doppler and pressure recordings before and after recanalization, and again after 5.0+/-1.3 months. Doppler (CFI) and pressure-derived collateral function indexes (CPI) and collateral (RColl) and peripheral resistance indexes (RP) were calculated. In 10 patients with reocclusion, all without myocardial infarction during follow-up, collateral function had reached a similar level as before the first recanalization. In the other 93 patients with or without restenosis, collateral function was attenuated during follow-up. CPI had decreased by 23% immediately after recanalization (P<0.001) and decreased further by another 23% at follow-up (P<0.001). The RColl increased immediately after recanalization by 82% (P<0.001) and by a further 273% at follow-up (P<0.001). In contrast, RP increased only by 22% after recanalization (P<0.001) and by an additional 12% at follow-up (P<0.05). The initial size of the collaterals but not the incidence of a restenosis influenced the collateral regression. Only 18% of patients at follow-up had collaterals with a CPI >0.30, presumably sufficient to prevent ischemia during acute occlusion. CONCLUSIONS: Collateral function regresses during long-term follow-up, especially in collaterals with a small diameter. In the majority of patients, collaterals are not readily recruitable in the case of acute occlusion. However, collaterals have the potential to recover in the case of chronic reocclusion.

Aged↗
PubMed2005

Revascularization end points in stroke interventional trials: recanalization versus reperfusion in IMS-I.

BACKGROUND AND PURPOSE: The acute stroke literature lacks a standard convention regarding the critical end point of revascularization. Two distinct parameters may be clinically important: (1) recanalization of the primary arterial occlusive lesion (AOL) and (2) global reperfusion of the distal vascular bed. We sought to determine their relationship in the Interventional Management of Stroke (IMS) Phase I trial of combined intravenous (IV) and intraarterial (IA) recombinant tissue plasminogen activator. METHODS: Sixty-one angiograms were reanalyzed using recanalization and reperfusion scores. The AOL Score was defined as: 0=no recanalization of the primary occlusion, I=incomplete or partial recanalization of the primary occlusion with no distal flow, II=incomplete or partial recanalization of the primary occlusion with distal flow, or III=complete recanalization of the primary occlusion with distal flow. The Thrombolysis in Myocardial Infarction (TIMI) Score was defined as: 0=no perfusion, 1=perfusion past the initial occlusion but no distal branch filling, 2=perfusion and incomplete or slow distal branch filling, or 3=full perfusion with filling of all distal branches. We compared the 2 scores with one another and with good clinical outcome (modified Rankin Score zero to 2). RESULTS: AOL and TIMI scores showed modest agreement (kappa, 0.30; confidence interval, 0.16 to 0.44). Good clinical outcome was seen in 49% of patients with AOL II/III scores (P=0.055) and 54% with TIMI 2/3 scores (P=0.019). The 2 methods did not significantly differ in predicting outcome (P=0.13). CONCLUSIONS: AOL recanalization and TIMI reperfusion scores comparably predict clinical outcome in this treatment paradigm. Other modalities may show different relationships between these 2 revascularization end points. Future studies should distinguish between these parameters semantically and methodologically.

Acute Disease↗
PubMed2000

High rate of complete recanalization and dramatic clinical recovery during tPA infusion when continuously monitored with 2-MHz transcranial doppler monitoring.

BACKGROUND AND PURPOSE: Clot dissolution with tissue plasminogen activator (tPA) can lead to early clinical recovery after stroke. Transcranial Doppler (TCD) with low MHz frequency can determine arterial occlusion and monitor recanalization and may potentiate thrombolysis. METHODS: Stroke patients receiving intravenous tPA were monitored during infusion with portable TCD (Multigon 500M; DWL MultiDop-T) and headframe (Marc series; Spencer Technologies). Residual flow signals were obtained from the clot location identified by TCD. National Institutes of Health Stroke Scale (NIHSS) scores were obtained before and after tPA infusion. RESULTS: Forty patients were studied (mean age 70+/-16 years, baseline NIHSS score 18.6+/-6.2, tPA bolus at 132+/-54 minutes from symptom onset). TCD monitoring started at 125+/-52 minutes and continued for the duration of tPA infusion. The middle cerebral artery was occluded in 30 patients, the internal carotid artery was occluded in 11 patients, the basilar artery was occluded in 3 patients, and occlusions were multiple in 7 patients; 4 patients had no windows; and 1 patient had a normal TCD. Recanalization on TCD was found at 45+/-20 minutes after tPA bolus: recanalization was complete in 12 (30%) and partial in 16 (40%) patients. Dramatic recovery during tPA infusion (total NIHSS score <3) occurred in 8 (20%) of all patients (baseline NIHSS range 6 to 22; all 8 had complete recanalization). Lack of improvement or worsening was associated with no recanalization, late recanalization, or reocclusion on TCD (C=0.811, P< or =0.01). Improvement by > or =10 NIHSS points or complete recovery was found in 30% of all patients at the end of tPA infusion and in 40% at 24 hours. Improvement by > or =4 NIHSS points was found in 62.5% of patients at 24 hours. CONCLUSIONS: Dramatic recovery during tPA therapy occurred in 20% of all patients when infusion was continuously monitored with TCD. Recovery was associated with recanalization on TCD, whereas no early improvement indicated persistent occlusion or reocclusion. At 24 hours, 40% of all patients improved by > or =10 NIHSS points or recovered completely. Ultrasonic energy transmission by TCD monitoring may expose more clot surface to tPA and facilitate thrombolysis and deserves a controlled trial as a way to potentiate the effect of tPA therapy.

Adult↗
PubMed2002

In situ beta radiation to prevent recanalization after coil embolization of cerebral aneurysms.

BACKGROUND AND PURPOSE: Endovascular treatment of cerebral aneurysms, a minimally invasive alternative to surgery, is too often followed by recanalization and recurrences. The purpose of this work was to assess if in situ beta radiation can inhibit recanalization after coil embolization. METHODS: Radioactive platinum coils (32P-coils) were produced by ion implantation of 32P. A single-coil arterial occlusion model was used to compare angiographic and pathological results at 1 to 12 weeks after nonradioactive and 32P-coil embolization of maxillary, cervical, and vertebral arteries in 26 dogs. Coils of varying activities were used and results compared to define the minimal activity required to inhibit recanalization. Similar experiments were performed in 16 porcine maxillary and lingual and 8 rabbit axillary arteries. Results of 32P-coil embolization of bifurcation aneurysms were then compared with embolization with nonradioactive coils in 12 dogs at 3 months. RESULTS: Nonradioactive coil embolization of canine arteries led to occlusion at 1 week, followed by recanalization at 2 weeks, which persisted at 3 months in all cases. 32P-coils, ion-implanted with activities above 0.13 microCi/cm, led to persistent occlusion at 3 months in 80% of arteries. 32P-coils ion-implanted with the same activity inhibited recanalization in porcine and rabbit arteries. Bifurcation aneurysms treated with 32P-coils had better angiographic results at 3 months (P=0.006) than aneurysms treated with nonradioactive coils. Arteries occluded were filled with fibrous tissue at 3 months. Aneurysms embolized with 32P-coils showed more complete neointimal coverage of the neck, without recanalization, as compared with aneurysms treated with nonradioactive coils. CONCLUSION: In situ low-dose beta radiation inhibits recanalization after coil embolization and may improve long-term results of endovascular treatment of aneurysms.

Animals↗
PubMed2006

Frequency and patterns of early recanalization after vasectomy.

BACKGROUND: Our understanding of early post-vasectomy recanalization is limited to histopathological studies. The objective of this study was to estimate the frequency and to describe semen analysis patterns of early recanalization after vasectomy. METHODS: Charts displaying serial post-vasectomy semen analyses were created using the semen analysis results from 826 and 389 men participating in a randomized trial of fascial interposition (FI) and an observational study of cautery, respectively. In the FI trial, participants were randomly allocated to vas occlusion by ligation and excision with or without FI. In the cautery study, sites used their usual cautery occlusion technique, two with and two without FI. Presumed early recanalization was based on the assessment of individual semen analysis charts by three independent reviewers. Discrepancies were resolved by consensus. RESULTS: Presumed early recanalization was characterized by a very low sperm concentration within two weeks after vasectomy followed by return to large numbers of sperm over the next few weeks. The overall proportion of men with presumed early recanalization was 13% (95% CI 12%-15%). The risk was highest with ligation and excision without FI (25%) and lowest for thermal cautery with FI (0%). The highest proportion of presumed early recanalization was observed among men classified as vasectomy failures. CONCLUSION: Early recanalization, occurring within the first weeks after vasectomy, is more common than generally recognized. Its frequency depends on the occlusion technique performed.

Follow-Up Studies↗
PubMed1992

Type and extent of hemispheric brain infarctions and clinical outcome in early and delayed middle cerebral artery recanalization.

We evaluated the influence of time of recanalization or degree of initial leptomeningeal collateral blood flow in cardioembolic or arterio-arterial middle cerebral artery (MCA) occlusion on infarct size and clinical outcome in a series of 34 consecutive acute stroke patients with main stem (N = 31) or major branch (N = 3) occlusions using CT, initial cerebral arteriography (N = 21), repetitive close-meshed transcranial Doppler ultrasonography, and a neurologic stroke scale. We treated 15 patients with tissue plasminogen activator intravenously within the first 6 hours. The type and size of infarction depended on the location of the occluding lesions within the MCA trunk. Proximal MCA occlusion always led to infarction involving the striatum and internal capsule. Sixty-five percent of patients showed recanalization of the occluded MCA within 1 week. Following MCA recanalization, hyperperfusion was present in 38 to 44% of cases. There was a marginally significant relation between size of infarction on CT and recanalization time within the first 24 hours. The more rapidly recanalization occurred, the smaller the size of the infarct. When recanalization time was greater than 8 hours, the lesions always extended to the cortex. An additional good leptomeningeal collateral blood flow significantly reduced the size of the infarct and improved clinical outcome after 17 days and after 10 months. Early recanalization of embolic MCA occlusions within up to 8 hours, in conjunction with good transcortical collateralization, has a favorable impact on infarct size and outcome and may constitute the therapeutic window of opportunity.

Aged↗