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PubMed1994

Determinants of patency after percutaneous angioplasty and atherectomy of occluded superficial femoral arteries.

BACKGROUND: Patients undergoing percutaneous recanalization of chronically occluded superficial femoral arteries were studied to determine which factors correlated with 1-year patency. Immediate change in ankle:brachial index (ABI), length of occlusion, tibial run-off, and the performance of supplemental catheter atherectomy were evaluated. METHODS: Eligible patients had at least one patient tibial run-off vessel and the absence of limb-threatening ischemia. Recanalization was performed via passage of a guidewire followed by balloon angioplasty. Tibial run-off was scored based on a modification of the angiogram scoring system of the Society for Vascular Surgery and the International Society for Cardiovascular Surgery. Supplemental transcutaneous extraction catheter atherectomy was randomly assigned to a sub-group of patients after initial experience with the recanalization technique. Clinical follow-up was employed to determine patency. RESULTS: Forty-two of 57 attempts (74%) at recanalization were immediately successful. Overall 1-year patency was 40% in 40 limbs that could be followed. In limbs with balloon angioplasty alone (n = 23), patency was 43% compared with 35% in those having supplemental atherectomy. Tibial run-off did not vary significantly between patent and occluded groups. When ABI increased by 0.3 or more, patency was 56% compared with 26% when the ABI increase was less than or equal to 0.1 (P = 0.13). Occlusion length averaged 18.1 +/- 10.6 cm for all limbs and did not vary significantly between early successes and failures. Limbs with short occlusions (less than or equal to 5 cm, n = 8) had 63% patency compared with 38% patency for limbs with long occlusions (greater than 25 cm, n = 16), but the difference was not significant by analysis of variance. CONCLUSIONS: An initial change in ABI was most predictive for patency, whereas no correlation with tibial run-off was demonstrated. Atherectomy did not increase patency. Short occlusions were more likely to remain patent than long ones, but overall patency was lower than described in other series.

Analysis of Variance↗
PubMed1991

Colour Doppler ultrasound of the post-phlebitic limb: sounding a cautionary note.

Colour Doppler ultrasound is accurate in the diagnosis of acute lower limb venous thrombosis. Some patients, however, will re-present with recurrent lower limb swelling following the acute event, and ultrasound may also become the primary imaging modality in these patients. We, therefore, undertook a prospective study of 20 patients with a diagnosis of deep venous thrombosis proven initially on both venography and ultrasound. Sixteen patients had thrombosis in the femoro-popliteal segment and four patients had isolated calf vein thrombosis. Patients with above knee thrombosis were scanned at 1, 3 and 6 months and those with isolated calf lesions at intervals of 1 week, 1 and 3 months. Results showed that in cases of above knee thrombosis, only 50% of patients showed complete recanalization by 6 months. The remaining 50%, by this time, showed only partial recanalization of thrombus, the features of which cannot be distinguished from acute non-occlusive thrombus. With respect to the four cases of isolated calf vein thrombosis, one case showed evidence of popliteal extension of thrombus, which by 3 months had fully recanalized. The remaining three cases recanalized completely without further thrombus extension. These results show that interpretation of the ultrasonic features of the post-phlebitic limb may be difficult in patients who re-present with lower limb swelling. Based on this study, we would advise routine scanning of all patients with above knee venous thromboses at 6 months to provide a baseline scan, permitting more accurate ultrasonic assessment of any future thrombotic events. This study also highlights the question of whether isolated calf vein thrombosis can safely be regarded as a benign entity.

Adult↗
PubMed1989

Thrombolytic therapy in acute myocardial infarction: Part II--rt-PA.

Thrombolysis with pharmacologic agents is a valuable modality for treatment of acute myocardial infarction. The results of several clinical studies indicate that early recanalization can be elicited with intravenous agents and that it is associated with substantial reductions of infarct size, improvement of ventricular function, and reduction in mortality. The recently introduced fibrin-selective agent, rt-PA, appears to represent a significant pharmacologic advance. Its use intravenously elicits high recanalization rates without marked derangements of the coagulation system, reflecting its relative fibrin selectivity. The efficacy of thrombolysis with any drug given by any route, unfortunately, is not 100 per cent. Bleeding remains an important risk. The optimal approach to management of residual stenosis after thrombolysis has not yet been delineated. Currently available information appears to justify the following conclusions: 1. Transmural myocardial infarction usually is caused by an acute obstructing coronary thrombus superimposed on a chronic atherosclerotic lesion. Myocardial necrosis following interruption of blood flow generally is complete within several hours. 2. The thrombus can be lysed and blood flow can be restored with intravenous agents that activate plasminogen. Intravenous rt-PA, a relatively fibrin-specific agent, elicits recanalization in 70 to 75 per cent of infarct-related arteries. 3. Recombinant t-PA evokes only modest depletion of fibrinogen (16 to 36 per cent reduction from baseline). 4. Early reperfusion preserves myocardium and ventricular function and reduces mortality. 5. The extent of benefit after pharmacologic reperfusion is correlated strongly with the brevity of myocardial ischemia prior to initiation of therapy. The greatest benefit is realized in patients treated within the first few hours of onset of acute myocardial infarction. 6. The incidence and optimal means of prevention of reocclusion and reinfarction following successful pharmacologic reperfusion are not yet entirely clear. Mechanical recanalization with PTCA in conjunction with thrombolysis is promising, but its routine immediate use on an emergency basis does not appear to be beneficial. Vigorous educational efforts are needed to heighten the awareness of prospective patients and all members of the health care team to the value of prompt diagnosis of incipient or evolving infarction so that prompt implementation of thrombolysis in appropriate candidates can be facilitated.

Heart↗
PubMed1988

Investigational use of tPA in acute stroke.

Significant current interest has focused on the possible value of fibrin-selective thrombolytic agents in acute stroke. Acute thrombosis contributes to carotid and vertebrobasilar arterial occlusions in the majority of acute stroke patients. Hence, fibrin(ogen)olytic agents may produce arterial recanalization and clinical benefit in thrombotic stroke. There are, however, unique features of cerebral tissue that suggest caution with the use of fibrin-selective agents in cerebral ischemia. The specific vascular anatomy and collateral flow suggest that salvage of the "ischemic penumbra" following vascular recanalization in focal ischemia is more likely to be successful than attempts in global ischemia. Recanalization may be associated with reperfusion injury and, more importantly, the risk of hemorrhagic transformation. There is little concrete information regarding the relative contribution of either event to post-thrombolysis cerebral injury. Early studies with exogenous fibrinolytic agents (urokinase, streptokinase) in completed stroke were regarded as inconclusive, demonstrating only an increased risk of intracerebral hemorrhage. Subsequent pilot studies in carotid and in vertebrobasilar territory thrombotic stroke have demonstrated that recanalization can result when exogenous agents are infused just proximal to the cerebral artery occlusion by interventional neuroradiological techniques. This experience and the advent of fibrin-selective agents (tissue plasminogen activator [tPA] and single-chain urokinase plasminogen activator) have led to the development of a multicenter prospective safety/dose-ranging study of tPA in acute (less than eight hours from symptom onset) thrombotic stroke. Following initial clinical assessment, computed tomography scan, and angiography, each patient with a documented cerebral artery occlusion appropriate to the clinical syndrome receives a preassigned intravenous dose of tPA over 60 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1997

A prospective, randomized, double-blind multicenter trial of a single bolus injection of the novel modified t-PA E6010 in the treatment of acute myocardial infarction: comparison with native t-PA. E6010 Study Group.

OBJECTIVES: This prospective, randomized, double-blind multicenter trial evaluated the efficacy and safety of a single bolus injection of the novel modified tissue-type plasminogen activator (t-PA) E6010 in the treatment of acute myocardial infarction compared with that of native t-PA. BACKGROUND: E6010 is a novel modified t-PA with a prolonged half-life (t1/2 alpha > or = 23 min) compared with native t-PA (t1/2 alpha = 4 min). E6010 can be administered in patients as a single intravenous bolus injection, and early recanalization can be expected. METHODS: The efficacy of E6010 was compared with that of native t-PA in 199 patients with acute myocardial infarction who were treated within 6 h of onset in a prospective, randomized, double-blind multicenter trial. Patients were given either 0.22 mg/kg body weight of E6010 intravenously over 2 min or native t-PA (tisokinase) 28.8 mg or 14.4 million IU (10% of the total dose over 1 to 2 min, the remainder infused over 60 min). RESULTS: The primary end point was the recanalization rate of the infarct-related coronary artery at 60 min after the start of treatment. Time to reperfusion was shorter in the E6010 group than in the native t-PA group. Thrombolysis in Myocardial Infarction flow grade 2 or 3 recanalization at 15, 30, 45 and 60 min after administration was observed in 37%, 62%, 74% and 79% (95% confidence interval [CI] 70% to 87%) of the E6010-treated patients and in 14%, 32%, 50% and 65% (95% CI 55% to 74%) of native t-PA-treated patients, respectively (p = 0.032 at 60 min). CONCLUSIONS: The present study indicates that, compared with native t-PA, a single bolus injection of E6010 over 2 min produces a higher rate of early recanalization of the infarct-related coronary artery without fatal bleeding complications.

Aged↗
PubMed1998

Determinants of chronic venous disease after acute deep venous thrombosis.

PURPOSE: The purpose of this investigation was to evaluate the relationship between the presenting features of an acute deep venous thrombosis (DVT), the subsequent natural history of the thrombus, and the ultimate outcome as defined according to the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery reporting standards in venous disease. METHODS: Patients with an acute DVT were followed with serial clinical and ultrasound examinations. Thrombus extent within 7 venous segments was scored retrospectively according to the reporting standards (scores ranged from 0 to 3), and segmental reflux was scored as present (1) or not present (0). The initial and final thrombus scores, the rates of recanalization and rethrombosis, and the total reflux scores were then calculated from these grading scales and related to ultimate chronic venous disease (CVD) classification. RESULTS: Sixty-eight patients with an acute DVT in 73 limbs were followed for 18 to 110 months (mean, 55 +/- 26 months). At the completion of the follow-up period, 20 extremities (27%) were asymptomatic (class 0), 13 (18%) had pain or prominent superficial veins (class 1), 25 (34%) had manifested edema (class 3), 13 (18%) had developed hyperpigmentation (class 4), and 2 (3%) had developed ulceration (class 5). In a univariate analysis, CVD classification was correlated with the reflux score (P =.003) but not with the initial or final thrombus score or with the rate of recanalization or rethrombosis. In a multivariate model of features documented at presentation, only the tibial thrombosis score was a significant predictor of CVD classification (R2 =.06). Outcome was better predicted (R2 =.29) with a model that included variables defined during follow-up the final reflux score, the final popliteal score, and the rate of recanalization. CONCLUSION: The ability to predict the severity of CVD after an acute DVT is currently limited, although the natural history appears more important than the presenting features of the event. The extent of reflux, the presence of persistent popliteal obstruction, and the rate of recanalization are related to ultimate CVD classification, but other determinants remain to be identified.

Acute Disease↗
PubMed2002

Experimental evaluation of a new transcatheter vascular embolization device in the swine model.

PURPOSE: To evaluate a new transcatheter device suitable for arterial embolization in an animal model. MATERIALS AND METHODS: A new prototype self-expanding braided embolic device (Embolizor), consisting of nitinol wire strands fixed at either end with platinum-iridium bands and covered with a film of polyethylene, was deployed through 5-F diagnostic catheters into renal artery branches in five swine. Standard stainless-steel spring coils were deployed in other renal branches and served as controls. The animals underwent follow-up selective renal arteriography to determine presence or absence of vessel recanalization or device migration 15-23 days after device deployment. Histopathologic evaluation of target vessels and peripheral renal parenchyma was also performed. RESULTS: Ten Embolizors and 10 stainless-steel coils were deployed in arteries ranging in size from 1.8 to 3.0 mm in diameter. The Embolizor was easily and precisely deployed. Angiographic evidence of vascular occlusion in the Embolizor group was noted within 30 seconds in eight device deployments and within 5 minutes in two. No early or delayed device migration was noted on follow-up arteriography. In the control group, seven of 10 previously occluded arteries were recanalized. No recanalization was noted in the Embolizor group. Light microscopy revealed evidence of infarction in all specimens examined. Whereas three specimens in the Embolizor group contained occasional giant cells, there were numerous multinucleated giant cells present within the interstices of all control spring coils. CONCLUSION: The Embolizor was easily, precisely, and successfully deployed through standard selective diagnostic angiographic catheters. Short-term follow-up demonstrated no recanalization or migration of the device. The Embolizor was shown on histopathologic analysis to have no significant foreign body reaction.

Alloys↗
PubMed1998

[Simple and effective rt-PA thrombolysis design].

PURPOSE: Assessment of a novel, simple and practical thrombolysis scheme for the purposes of a central hospital. MATERIALS AND METHODS: 314 thromboembolic lower extremity occlusions in 260 consecutive patients were treated by thrombolysis as follows: 6 ml rt-PA/h for 30 min; 3 ml rt-PA/h for another 30 min; 1 ml rt-PA/h for 7 hours, and 0.4 ml rt-PA until vessel patency. Antegrade introduction of a 5 F straight end-hole catheter through a 6 F, constantly heparin-flushed sheath, to the level of occlusion was followed by subsequent advancement of the catheter tip according to progress of lysis at time intervals of 2, 4, and 8 hours. The regimen was continued overnight. RESULTS: 82% of arterial occlusions were completely recanalized at the end of thrombolysis. Then, angioplasty was performed if appropriate. Best results (100% recanalization rate) were achieved by treating occlusions of the superficial femoral artery, even in cases of involvement of the entire length of the vessel, and isolated popliteal occlusions. A recanalization rate of 70% was achieved by treating distal crural vessel occlusion. Bypass grafts were recanalized in 50%. COMPLICATIONS: 3 x major hematoma, 2 x transluminal perforation; 16 x minor hematoma from the puncture site at the sheath, 4 x erythema, obviously reaction to rt-PA (together n = 25; 8%). CONCLUSIONS: We empirically found and solidly evaluated an effective thrombolysis scheme. Our results demonstrate that major advances are possible even in this well-grounded field.

Adult↗
PubMed1982

[Fibrinolytic treatment of acute and subacute thromboses of the deep veins of the shoulder girdle (author's transl)].

19 patients were treated with streptokinase and (or) urokinase for primary thrombosis of the subclavian and (or) axillary vein (Paget-von-Schroetter-syndrome) of 2 to 28 days' duration. Phlebograms revealed significant improvement in 18 of the 19 patients (complete recanalization in 11, partial recanalization in 7). In those 17 patients whose symptoms had been present for up to 2 weeks the clinical outcome was entirely independent of the delay between the appearance of first symptoms and the start of fibrinolytic therapy, and even in the 2 patients wih an even longer delay complete recanalization was achieved in one (delay of 3 weeks) and partial recanalization in the other (delay of 4 weeks). However, since major clinical improvement occurs also spontaneously in most patients, a clear indication for fibrinolytic therapy exists only in particularly young patients and in those patients who depend on an absolutely perfect function of their upper extremities. In addition, the good results obtained with delayed fibrinolytic therapy justify extending this indication to those remaining patients in whom prior conservative management with elevation of the arm and anticoagulant therapy does not result in sufficient clinical improvement.

Adult↗
PubMed2002

Regional hyperthermic fibrinolytic perfusion after unsuccessful venous thrombectomy of extensive deep venous thrombosis.

OBJECTIVE: Because of the dose-dependent increase in bleeding complications, the intraoperative administration of fibrinolytic agents is limited. This limitation impairs the efficacy of fibrinolytic therapy because low-dose fibrinolysis often fails in the treatment of complex deep venous thrombosis (DVT). The aim of this study was to investigate the efficacy and safety of intraoperative high-dose fibrinolytic therapy for extended DVT, which was performed with the regional hyperthermic fibrinolytic perfusion (RHFP) technique. METHODS: From January 1993 to June 2001, in 53 patients with extended DVT, unsuccessful venous thrombectomy (recanalization, <50%) was followed by RHFP with 0.5 mg/kg of body weight of recombinant tissue plasminogen activator. The extent of thrombosis was documented before, during (after the surgical thrombectomy), and after (between postoperative days 2 and 5) surgery with phlebography and was quantified with the Marder score. Intraoperative and postoperative complications were recorded prospectively. RESULTS: After RHFP, a recanalization was achieved in 64 of 146 venous segments (43.8%) that were still occluded despite thrombectomy. Eighty-two segments (56.2%) remained occluded. Compared with the preoperative phlebography, 32 patients (60.3%) had a successful recanalization (>50%). Eleven patients (20.8%) showed minimal and 10 patients (18.9%) no recanalization. No lethal complications occurred. One patient (1.9%) had pulmonary embolism develop, and two patients (3.8%) had bleeding complications develop. CONCLUSION: With the intraoperative use of hyperthermia-assisted high-dose fibrinolysis, improvement of the results of mechanical thrombectomy of extended DVT was possible. The RHFP protected against systemic side effects of the fibrinolysis and show a high safety of application.

Adult↗
PubMedDate not supplied

Long-term results of primary stenting for long and complex iliac artery occlusions.

OBJECTIVES: To evaluate the long-term results of recanalization with primary stenting for long and complex iliac artery occlusions. DESIGN: Retrospective non-randomized study. METHODS: Between 1996 and 2004, 38 patients underwent recanalization of an occluded iliac artery with subsequent stenting for TASC B lesions in 12 patients, TASC C in 10 and TASC D in 16. Thirty-one patients had Fontaine stage 2 B, four patients had stage 3 and one patient had stage 4. Two patients (5.4%) presented with acute ischemia and received trombolysis before recanalization. Patency results were calculated using Kaplan and Meier analysis. The mean follow-up was 26 months. RESULTS: Technical success was 97.4%. Thirty-day mortality was 2.7%. The primary patency rate was 94%, 89% and 77% at 1, 3 and 5 years respectively. Three re-occlusions (8.1%) and one restenosis (2.7%) were observed during follow-up. The secondary patency (SP) rate was 100%, 94% and 94% after 1, 2 and 3 years. Fifteen patients underwent an associated procedure. A kissing stent procedure in three patients, a contralateral PTA of an iliac stenosis in 8, a femoro-femoral bypass in 2, a femoropopliteal bypass in 1 and an femoral endarterectomy in 2. The procedure related complication rate was 5.4%. CONCLUSION: Long-term results of iliac recanalization are excellent without major complications if the procedure is technically successful. The endovascular procedure can be an alternative to an iliofemoral or aortobifemoral bypass in a high risk population.

Adult↗
PubMed2000

Intravascular ultrasound angioplasty in peripheral arterial occlusion. Preliminary experience.

PURPOSE: To determine if ultrasound angioplasty in a percutaneous approach was capable of recanalizing occluded arteries in acute and subacute peripheral arterial occlusions. MATERIALS AND METHODS: We applied an ultrasound angioplasty device in a percutaneous approach in 9 patients with peripheral arterial occlusions. All patients suffered from severe leg ischemia due to subacute thrombotic occlusions. RESULTS: The ultrasound transmitter easily created a channel within the occlusive material. To further reduce the mass of the occlusive material, an aspiration thrombectomy was performed in all cases, leading to a complete recanalization in 7 cases. In 2 cases, a remaining stenosis was successfully dilated. CONCLUSION: Intravascular ultrasonic devices can be useful for recanalization of occluded peripheral arteries. In particular, if thrombolytic therapy of longer peripheral arterial occlusions fails or is contraindicated, ultrasound angioplasty may be a new approach for recanalization.

Acute Disease↗
PubMed2004

Treatment of long superficial femoral artery occlusions with excimer laser angioplasty: long-term results after 48 months.

PURPOSE: To evaluate clinical and hemodynamical long-term results after laser angioplasty of long occlusions of the superficial femoral artery (SFA). MATERIAL AND METHODS: In a prospective trial of 452 patients with long occlusions of the SFA, excimer percutaneous transluminal laser angioplasty (PTLA) for recanalization was applied. The average occlusion length of the SFA was 25.5 cm (range 16-38 cm). The recanalization attempt was done with the crossover technique in 398 patients, in 36 patients with the antegrade technique and in another 18 patients with the transpopliteal technique. RESULTS: The application of laser angioplasty demonstrated a successful recanalization of the SFA in 386/452 patients (85.5%). Recanalization with PTLA was not possible in 66 patients (14.5%). The main reason for the unsuccessful PTLAs was obstructing calcified material (n = 28) resistant to PTLA application. After a follow-up period of 48 months there was a primary, primary-assisted, and secondary patency rate of 22.3%, 40.9%, and 43.2%, respectively. CONCLUSION: Laser angioplasty of long occlusions of the SFA is a feasible procedure with a low failure rate. Long-term results are promising, but additional interventions are required in most patients if a patency rate of 43.2% is to be achieved after 4 years.

Adult↗
PubMed1998

Portal and splanchnic haemodynamics in patients with advanced post-hepatitic cirrhosis and in healthy adults. Assessment with duplex Doppler ultrasound.

PURPOSE: To assess portal and splanchnic haemodynamics, and splanchnic vascular resistance in patients with advanced post-hepatitic cirrhosis and in healthy volunteers, by means of duplex Doppler ultrasound (US). MATERIAL AND METHODS: The duplex Doppler US examination was performed in 16 patients with cirrhosis and in 24 healthy volunteers. We investigated vessel diameters, mean flow velocities, and mean blood flows in the portal vein, the superior mesenteric artery (SMA), and the splenic artery (SA), and measured the resistive index values of SMA and SA. RESULTS: The mean portal venous blood flow in patients with cirrhosis (829 +/- 264 ml/min) was not statistically different from those in the volunteers (734 +/- 194 ml/min). The ratio of the SMA and SA blood flows (621 ml/min) to the portal venous blood flow (734 ml/min) was 0.85 in the control subjects. The mean portal venous blood flow (1261 ml/min) and the portal venous velocity (14.6 cm/s) were higher in the patients with recanalized para-umbilical veins than in the volunteers and in the patients without recanalized para-umbilical veins. The SMA and SA blood flows were significantly increased in patients with cirrhosis compared with volunteers. Splanchnic inflow (the sum of the SMA and SA blood flows) was higher than the portal blood flow in patients with cirrhosis except in the subjects with recanalized para-umbilical veins. SMA and SA resistive index values were significantly higher in these patients than in the volunteers. CONCLUSION: Splanchnic blood flow and splanchnic vascular impedance increased significantly in patients with advanced post-hepatitic cirrhosis. Splanchnic inflow must not exceed portal venous blood flow in patients with recanalized para-umbilical veins. Portal vein velocity and portal venous blood flow measurements alone are not useful parameters for discriminating patients with cirrhosis from healthy subjects.

Adult↗
PubMed2005

Percutaneous coronary intervention for chronic total occlusions: the Thoraxcenter experience 1992-2002.

AIMS: Chronic total occlusions (CTOs) are commonly found on diagnostic angiography, and there is some evidence from one study that successful percutaneous revascularization leads to an improvement in long-term survival rates. However, this study included patients treated for unstable angina with short-duration occlusion, and stent implantation was utilized in only 7%. We re-evaluated the long-term outcomes of a large consecutive series of patients with a CTO of >1-month duration treated at our centre, with stent implantation utilized in the majority. METHODS AND RESULTS: All patients treated with percutaneous coronary intervention (PCI) between 1992 and 2002 were retrospectively identified from a dedicated database. A total of 874 consecutive patients were treated for 885 CTO lesions. Mean follow-up time was 4.47 +/- 2.69 years (median 4.10 years). Patients were evaluated for the occurrence of major adverse cardiac events (MACE) comprising death, acute myocardial infarction, and need for repeat revascularization with either coronary artery bypass surgery or PCI. Successful revascularization was achieved in 576 lesions (65.1%), in which stent implantation was used in 81.0%. At 30 days, the overall MACE rate was significantly lower in those patients with a successful recanalization (5.5 vs. 14.8%, P < 0.00001). At 5 years, survival was significantly higher in those patients with a successful revascularization (93.5 vs. 88.0%, P = 0.02). In addition, there was a significantly higher survival free of MACE (63.7 vs. 41.7%, P < 0.0001), with the majority of events reflecting the need for repeat intervention. Independent predictors for survival were successful revascularization, lower age, and the absence of diabetes mellitus and multivessel disease. CONCLUSION: Successful percutaneous revascularization of a CTO leads to a significantly improved survival rate and a reduction in major adverse events at 5 years. Most events relate to the need for repeat reintervention, and the introduction of drug-eluting stents, with low-restenosis rates, encourages the development of technologies to improve recanalization success rates. However, failed recanalization may be associated acutely with an adverse event, and new technologies must focus on a safe approach to successful recanalization.

Aged↗
PubMed1995

Beneficial effect of nitroglycerin on arterial rethrombosis after thrombolysis. Results from a rabbit thrombosis model.

BACKGROUND: Although nitroglycerin (NTG) is commonly administered to patients with acute myocardial infarction, its effect on concomitant thrombolytic therapy has not been fully elucidated. We examined whether NTG administration further optimizes thrombolysis with rt-PA, combined with aspirin and heparin. METHODS AND RESULTS: Blood clots were produced in a rabbit femoral artery with endothelial damage and distal stenosis. rt-PA was administered in repeated bolus i.v. injections of 0.3 mg.kg-1 every 10 min for 50 min. Femoral artery flow was measured continuously for 2 h. Fourteen rabbits were randomized into two groups (group A and B), both receiving aspirin (i.v. 17 mg.kg-1) and heparin (i.v. 200 units.kg-1) prior to the first rt-PA bolus injection. NTG was administered in group B only, 10 min prior to the first rt-PA bolus, at 10 micrograms.kg-1.min-1 for 130 min. Reperfusion at the end of the 120 min observation period occurred in 5/7 group A and 6/7 group B rabbits (P = ns). In 3/7 group A rabbits, re-flow was achieved but persistent re-occlusion subsequently developed in 1/3 and oscillatory re-flow and re-occlusion cycles (cyclic re-flow) with subsequent patency developed in the remaining two rabbits. These flow patterns were not observed in any of group B rabbits. Overall patency duration was significantly prolonged with NTG (group B; 578/840 min) compared to controls (group A; 258/840 min) (P < 0.001). The mean recanalization time (group A; 30.8 +/- 9.3 vs group B; 22.5 +/- 4.7 min, P = 0.16) as well as mean rt-PA boluses needed to achieve complete recanalization (group A; 4.3 +/- 0.7 vs group B; 3.3 +/- 0.6 boluses/rabbit, P = 0.3) did not differ between groups. However, NTG infusion was associated with increased restored femoral flow following recanalization (expressed as % of stenotic flow value over observation time) compared to control group (P = 0.025 by repeated measures ANOVA). CONCLUSION: Adding NTG to a thrombolytic regimen with rt-PA, aspirin and heparin increases the magnitude of restored flow and total patency duration following recanalization in a rabbit model of arterial thrombosis.

Animals↗
PubMed2002

Aggressive mechanical clot disruption and low-dose intra-arterial third-generation thrombolytic agent for ischemic stroke: a prospective study.

OBJECTIVE: We prospectively evaluated the safety and effectiveness of aggressive mechanical disruption of clot in conjunction with intra-arterial administration of a low-dose third-generation thrombolytic agent (reteplase) to treat ischemic stroke in patients who were considered poor candidates for intravenous alteplase therapy or who failed to improve after intravenous thrombolysis. Mechanical clot disruption was used if low-dose pharmacological thrombolysis was ineffective. This strategy was adopted to increase the recanalization rate without increasing the risk of intracerebral hemorrhage. METHODS: Patients were considered poor candidates for intravenous therapy because of severity of neurological deficits, interval from symptom onset to presentation of at least 3 hours, or recent major surgery. We administered a maximum total dose of 4 U of reteplase intra-arterially in 1-U increments via superselective catheterization. After the initial doses were administered, we performed mechanical angioplasty (for proximal occlusion) or snare manipulation (for distal occlusion) at the occlusion site if recanalization had not occurred. The remaining doses of thrombolytics were subsequently administered if required for further recanalization. Angiographic responses were graded using modified Thrombolysis in Myocardial Infarction (TIMI) criteria. Clinical evaluations were performed before and 24 hours, 7 to 10 days, and 1 to 3 months after treatment. RESULTS: Nineteen consecutive patients were treated (mean age, 64.3 +/- 16.2 yr; 10 were men). Initial National Institutes of Health Stroke Scale scores ranged from 11 to 42. Time from onset to treatment ranged from 1 to 9 hours. Occlusion sites were in the following arteries: cervical internal carotid (n = 7), intracranial internal carotid (n = 1), middle cerebral (n = 9), and basilar (n = 2). Of the 19 patients, thrombolysis alone was used in 5 patients, angioplasty was performed in 11 patients, and snare maneuvers were used in 5 patients. Complete restoration of blood flow (modified TIMI Grade 4) was observed in 12 patients, near-complete restoration of flow (modified TIMI Grade 3) in 4 patients, minimal response (modified TIMI Grade 1) in 1 patient, and no response in 2 patients (modified TIMI Grade 0). Neurological improvement at 24 hours (decline of at least 4 points in National Institutes of Health Stroke Scale score) was observed in seven patients. Five other patients experienced further improvement in National Institutes of Health Stroke Scale score at 7 to 10 days. No vessel rupture, dissection, or symptomatic intracranial hemorrhages were observed. At the time of follow-up evaluation, 7 of 19 patients were functionally independent. CONCLUSION: A high rate of recanalization and clinical improvement can be observed in patients with ischemic stroke using low-dose thrombolytic agents with adjunctive mechanical disruption of clot. Moreover, this strategy may reduce the risk of intracerebral hemorrhage observed with thrombolytics.

Adult↗
PubMed2002

Capillary embolization using ethiodol-ethanol for complete renal ablation in Swine.

RATIONALE AND OBJECTIVES: To evaluate the effect of capillary embolization with superselectively administered 1:1 Ethiodol-ethanol mixture (EEM) for complete nephrectomy in normal porcine kidneys. MATERIALS AND METHODS: One kidney in each animal was completely embolized by sequential segmental arterial injections of the EEM via a microcatheter until complete capillary stasis occurred. Group 1 (n = 5): Initial embolization did not occlude the arterial compartment. Group 2 (n = 7): The capillary embolization was performed in conjunction with absolute ethanol injection and coil placement during balloon catheter occlusion. RESULTS: Group 1: Complete recanalization occurred following the EEM embolization (1-week). After the repeat embolization (EEM + pure ethanol without balloon occlusion), three of five kidneys showed partial recanalization (2-weeks). Following a third embolization (EEM + coil) in two pigs, one kidney showed partial recanalization (12-weeks). Group 2: Complete renal artery occlusion was achieved in all kidneys with no recanalization. Histologically, four kidneys exhibited total ablation whereas three showed minimal preexisting parenchyma (8-weeks). CONCLUSIONS: Permanent arterial occlusion with histologically complete renal ablation was achieved using a two-phase technique of homogeneous capillary embolization with 1:1 EEM and ethanol and coil occlusion performed during temporary balloon occlusion. Sequential segmental EEM injections alone did not produce permanent capillary embolization.

Animals↗