Peripheral artery occlusion: treatment with abciximab plus urokinase versus with urokinase alone--a randomized pilot trial (the PROMPT Study). Platelet Receptor Antibodies in Order to Manage Peripheral Artery Thrombosis

PURPOSE

To evaluate the combination of a platelet glycoprotein IIb/IIIa complex receptor inhibitor and urokinase for treatment of recent (<or=6 weeks) arterial occlusion of the legs.

MATERIALS AND METHODS

Seventy patients with lower extremity arterial occlusion of less than 6 weeks duration were randomly separated into two treatment groups: urokinase plus abciximab or urokinase plus placebo. Primary end points were the rate of major complications at 30 days after randomization and the rates of amputation-free survival and survival without open surgery or major amputation at follow-up of 90 days. Two readers unaware of the patients' treatment group assignments analyzed digital subtraction angiograms as they related to the study end points, with a final consensus reading.

RESULTS

Thrombolysis relative to clot length was faster in the urokinase-plus-abciximab group (odds ratio, 0.52; 95% CI: 0.35, 0.76; P < .001). There were no procedure-related deaths or intracranial hemorrhages, but the rate of nonfatal major bleeding was higher with urokinase plus abciximab (four of 50 patients) than with urokinase alone (none of 20 patients; P = .32). At 90 days, amputation-free survival was 96% (48 of 50 patients) in the urokinase-plus-abciximab group compared with 80% (16 of 20 patients) in the urokinase alone group. The hazard ratio for the two Kaplan-Meier curves was 0.42 (95% CI: 0.16, 0.96; P = .04).

CONCLUSION

In patients with lower extremity arterial occlusion who were undergoing urokinase thrombolysis, adjunctive abciximab treatment resulted in faster thrombus dissolution and improved amputation-free survival, despite an increase in major bleeding.

Lack of efficacy of twice-weekly urokinase in the prevention of complications associated with Hickman catheters: a multicentre randomised comparison of urokinase versus heparin

Hickman catheters (HC) are associated with complications, in particular infection, occlusion and thrombosis. We tested the hypothesis that regular flushing of catheters with urokinase would reduce the frequency of these complications. Patients who required a double-lumen HC for (1) bone marrow or peripheral blood progenitor cell transplantation or (2) intensive combination chemotherapy for haematological malignancies were randomised to receive twice-weekly flushes of either urokinase (5000 units) or heparin (50 units). HC-survival analysis was determined by Cox regression. 100 patients were enrolled (urokinase=52; heparin=48) and treated for a mean of 8.5 weeks. No significant difference was observed in the incidence of HC-associated septicaemic events, which occurred in 8/52 in the urokinase group and 9/48 in the heparin group (actuarial incidence 20% versus 25%, P=0.50). Similarly, there was no differences in the incidence of exit site infections (urokinase=27/52 and heparin=28/48, P=0.122); HC-septic thromboses (urokinase=2/52 and heparin=4/48, P=0.34); lumen occlusion (urokinase=30/52 and heparin=30/48, P=0.681); or venous thrombosis (urokinase=8/52 and heparin=6/48, P=0.726). Overall, a high incidence of HC-related complications was seen in both groups; 40/52 in the urokinase group and 40/48 in the heparin group (actuarial incidence 80% versus 90%, P=0.367). Despite this only 18% of HC required early removal due to complications (urokinase=8, heparin=10). There was no difference in the incidence of complications in patients undergoing transplantation (n=68) compared with chemotherapy alone (n=32). Patients with haematological malignancies were more likely to have HC-related infective complications (P=0.006), and patients with solid tumours more likely to have venous thrombosis (P=0.027). The cumulative incidence of HC-related complications in this prospective study was higher than in previously reported series. Urokinase did not appear effective in reducing the frequency of these complications.

Recombinant tissue plasminogen activator versus urokinase for local thrombolysis of femoropopliteal occlusions: a prospective, randomized multicenter trial

PURPOSE

To report the outcome of a prospective, randomized, open multicenter trial comparing (1) the effects of local thrombolysis with recombinant tissue plasminogen activator (rtPA) or urokinase (UK) and (2) 2 administration techniques.

METHODS

Two hundred thirty-four patients with thromboembolic occlusions in 223 native femoral or popliteal arteries (95%) and 11 bypass grafts (5%) were randomized to rtPA (n = 124) or UK (n = 110) administered either through an endhole catheter (Hess technique) in 81 patients or a microporous balloon catheter (Schneider technique) in 153 patients. When lysis was incomplete, additional catheter interventions were applied to achieve patency. Results were analyzed by fluoroscopy during intervention and by angiography evaluated by independent experts blinded to the methods applied.

RESULTS

The only significant difference between rtPA and UK was found at the end of lysis using the Hess technique. Complete reperfusion (TIMI grade 3) was produced in 60% of patients by rtPA versus 37% by UK (p = 0.045). By both techniques TIMI grade 3 was achieved in 62% with rtPA and in 50% with UK (p = 0.18). Independent of delivery technique, thrombolytic agent, or additional catheter interventions, TIMI grade 3 was achieved in 81% and angiographic patency in 88%. Primary patency at 6 months was 66%, which was increased by secondary interventions to 75%. Major amputations were performed in 6%, all in patients with initial Fontaine stage III/IV ischemia.

CONCLUSIONS

With local thrombolysis alone, rtPA appears to be more effective than UK; however, additional catheter interventions further improved patency, abolishing the difference between the lytic agents.

[Thrombolytic therapy as pretreatment before vascular operations and radiologic interventions]

The authors describe their 60 cases of thrombolysis with steptokinase (SK). Thrombolysis was required in 55 patients because of arterial, while in 5 patients because of venous side thrombosis. The 73% of the patients with arterial occlusion where thrombolysis was applied belonged Fountain stage IV, while 27% to Fountain stage III. Graft occlusion occurred in 60% of all cases and the acute or subacute thrombosis of the native vessels required thrombolysis in 40%. The thrombolysis alone was sufficient in 26 patients, while it was completed with PTA in 9, with PTA and implantation of stent in 1 and with vascular surgical procedure in 10 cases. Reconstruction surgery was the final solution in 4 patients, for whom the thrombolysis was inadequate. Amputation was unavoidable in 8 cases. The thrombolysis therapy was successful in 77% in our experience. The high number of hemorrhagic complications was due to the bleeding of puncture hole. It needed surgical suture in 10 cases.

Intravenous tissue-type plasminogen activator therapy for ischemic stroke: Houston experience 1996 to 2000

CONTEXT

Intravenous tissue-type plasminogen activator (tPA) therapy using the National Institute of Neurological Disorders and Stroke criteria has been given with variable safety to less than 5% of the patients who have ischemic strokes nationwide. Our center is experienced in treating large numbers of stroke patients with intravenous tPA.

OBJECTIVE

To report our total 4-year experience in the treatment of consecutive patients who had an ischemic stroke.

DESIGN

Prospective inception cohort registry of all patients seen by our stroke team and an additional retrospective medical record review of all patients treated between January 1, 1996, and June 1, 2000.

SETTING

A veteran stroke team composed of fellows and stroke-specialty faculty servicing 1 university and 3 community hospitals in a large urban setting.

PATIENTS

Consecutive patients with ischemic stroke treated within the first 3 hours of symptom onset.

INTERVENTION

According to the National Institute of Neurological Disorders and Stroke protocol, 0.9 mg/kg of intravenous tissue-type plasminogen activator was administered.

MAIN OUTCOME MEASURES

Number and proportion treated, patient demographics, time to treatment, hemorrhage rates, and clinical outcome.

RESULTS

A total of 269 patients were treated between January 1, 1996, and June 1, 2000. Their mean age was 68 years (age range, 24-93 years); 48% were women. This represented 9% of all patients admitted with symptoms of cerebral ischemia at our most active hospital (over the final 6 months, 13% of all patients with symptoms of cerebral ischemia and 15% of all acute ischemic stroke patients). Before treatment the mean +/- SD National Institutes of Health Stroke Scale (NIHSS) score was 14.4 +/- 6.1 points (median, 14 points; range, 4-33 points). A tPA bolus was given at 137 minutes (range, 30-180 minutes); 28% of the patients were treated within 2 hours. The mean door-to-needle time was 70 minutes (range, 10-129 minutes). The symptomatic intracerebral hemorrhage rate was 5.6% of those patients with a second set of brain scans (4.5% of all patients), with a declining trend from 1996 to 2000. Protocol violations were found in 13% of all patients; the symptomatic intracerebral hemorrhage rate in these patients was 15%. At 24 hours, the NIHSS score was 10 +/- 8 points (median, 8 points; range, 0-36 points). In-hospital mortality was 15% and the patients' discharge NIHSS scores were 7 +/- 7 points (median, 3 points; range, 0-35 points).

CONCLUSIONS

Intravenous tPA therapy can be given to up to 15% of the patients with acute ischemic stroke with a low risk of symptomatic intracerebral hemorrhage. Successful experience with intravenous tPA therapy depends on the experience and organization of the treating team and adherence to published guidelines.

Repeated doses of tissue plasminogen activator for failed thrombolysis: case report and review of the literature

This article reports the first case of a patient presenting with acute myocardial infarction in whom a repeated dose of tissue plasminogen activator (t-PA) was able to achieve successful thrombolysis after a first dose of t-PA itself failed to do so. This case report presents an alternative approach for the treatment of patients who fail thrombolysis after an initial dose of t-PA, an approach that might be particularly useful in hospitals that do not have immediate access to advanced interventional services.

Alteplase: descendancy in myocardial infarction, ascendancy in stroke

Tissue type plasminogen activator is available, through recombinant technology, for thrombolytic use as alteplase. Alteplase is relatively clot specific and should cause less bleeding side effects than the non-specific agents such as streptokinase. Alteplase has been used successfully in evolving myocardial infarction (MI) to reopen occluded coronary arteries. It is probably equally effective or superior to streptokinase in opening arteries and reducing mortality in MI. Alteplase is most effective when given early in MI and is probably ineffective when given 12 h after the onset of symptoms. The effectiveness of alteplase in MI can be increased by front loading with a bolus of 15 mg, followed by an infusion of 50 mg over 30 min and 35 mg over 60 min. Percutaneous transluminal coronary angioplasty or stenting is associated with a greater patency and lower rates of serious bleeding, recurrent ischaemia and death than alteplase in MI and is likely to take over from alteplase as the standard MI treatment. A reduced dose of alteplase to increase coronary artery patency prior to angioplasty may be useful in MI. An exciting new indication for the use of alteplase is in stroke, where it has become the first beneficial intervention. Alteplase is used to reopen occluded cerebral vessels but is associated with an increased risk of intracerebral haemorrhage. Alteplase is beneficial if given within 3 h of the onset of stroke but not after this time period. Therefore, the next challenge is to increase the percentage of people being diagnosed and treated within this period. Clinical trials have not established a role for alteplase in the treatment of acute coronary syndromes or deep vein thrombosis. However, alteplase is useful in treating pulmonary thromboembolism and peripheral vascular disease.

Safety and efficacy of limited-dose tissue plasminogen activator in acute vascular occlusion

OBJECTIVE

The purposes of this study were to evaluate the safety and efficacy of limited-dose tissue plasminogen activator (t-PA) in patients with acute vascular occlusion and to compare these results with those obtained in equivalent patients receiving urokinase.

METHODS

We compared the results of 60 patients receiving catheter-directed urokinase from November 1997 to November 1998 (240,000 units/h x 4 h, 120,000 units/h thereafter for a maximum of 48 h) with those of 45 patients receiving catheter-directed t-PA from November 1998 to August 2000 (2 mg/h, total dose < or =100 mg) for acute arterial occlusion (AAO) and acute venous occlusion (AVO). Interventional approaches such as cross-catheter and coaxial techniques were used to reduce the dose of lytic agent needed to achieve pre-lysis-treatment goals (eg, complete lysis of all thrombus/unmasking graft stenosis or establishing outflow target). Statistical analysis was performed using Student t test and Fisher exact test.

RESULTS

The urokinase and t-PA groups were comparable with regard to age, comorbidities (coronary artery disease, hypertension, diabetes, renal insufficiency, smoking), duration of ischemic or occlusive symptoms, location of occlusive process, pretreatment with warfarin, and thrombotic versus embolic and native versus graft occlusion in patients with AAO. In patients with AAO and in those with AVO, t-PA was equivalent to or better than urokinase with regard to percent of clot lysis, incidence of major bleeding complications, limb salvage, and mortality. Achievement of pretreatment goals (arterial patients only) was 50% for urokinase patients and 76% for t-PA patients (P =.02). Analysis of success in individual pretreatment-goal achievement showed urokinase and t-PA to be equivalent in unmasking stenoses (85% and 84%, respectively; P = NS), whereas t-PA was superior to urokinase in the more critical task of establishing run-off (39% versus 81% for urokinase and t-PA, respectively; P =.001). Additional interventions, either endovascular or surgical, were required in 60% and 51% (P = NS) of patients receiving urokinase and t-PA, respectively, for AAO, and in 54% and 62% (P = NS) of patients receiving urokinase and t-PA, respectively, for AVO.

CONCLUSIONS

Limited-dose t-PA is a safe and effective therapy for AAO and AVO when administered by experienced teams using innovative but well-established interventional techniques.

[Fibrinolysis in pulmonary embolism]

A POTENTIALLY FATAL CONDITION: Pulmonary embolism (PE) is a potentially fatal disorder for which heparin therapy improves the outcome. In spite of anticoagulation, mortality of PE remains high, especially when associated with shock or right ventricular dysfunction. THROMBOLYSIS: Indications of thrombolytic therapy in the treatment of PE remain relatively undefined. It is well established that thrombolytic therapy achieves a more rapid but not more complete dot lysis than heparin alone. RANDOMIZED STUDIES: Only one randomized add prospective study including 8 patients with massive PE associated with shock found a beneficial effect of thrombolysis treatment regarding mortality. The other studies which involved 453 patients did not find such a beneficial effect of thrombolysis on mortality. There is no convincing evidence suggesting beneficial effect of thrombolysis regarding PE recurrence or long term recovery. However, there is an increasing risk of major bleeding when using thrombolytic agents. In summary, thrombolytic therapy use should be restricted to patients who have hemodynamic instability in absence of absolute contraindications. A large-scale prospective randomized controlled trial, comparing heparin alone and thrombolysis therapy is needed to clarify the indications of these treatments.

Thrombosed hemodialysis grafts: lyse and wait with tissue plasminogen activator or urokinase compared to mechanical thrombolysis with the Arrow-Trerotola Percutaneous Thrombolytic Device

PURPOSE

To determine if the lyse and wait (L&W) technique with a 4-mg dose of alteplase (tissue plasminogen activator; tPA) is a safe and effective method of declotting dialysis grafts as compared to use of the Arrow-Trerotola Percutaneous Thrombectomy Device (PTD) or the L&W technique with use of urokinase (UK).

MATERIALS AND METHODS

Forty patients were randomized prospectively to undergo L&W declotting with use of 4 mg of tPA or mechanical thrombolysis with the PTD. The time interval to restored graft flow, total procedure time, hemostasis time, and anatomic success, clinical success, complications, and patency rates were analyzed. These were compared with historic results in 20 patients treated with the L&W technique with use of 250,000 U UK.

RESULTS

The immediate anatomic success rate was 95% in the tPA L&W and PTD groups. The mean in-room lysis time with restored flow was 10 minutes for L&W with tPA and 19 minutes for PTD (P = .002). The mean in-room procedure time was 39 minutes for L&W and 45 minutes for PTD (P = NS). Mean hemostasis time with use of manual compression was 44 minutes for L&W with tPA and 23 minutes for PTD (P = .057). The historic group of 20 patients who underwent L&W with UK had a 95% anatomic success rate, a mean of 14 minutes of lysis time, a mean of 34 minutes of procedure time, and a mean of 26 minutes of time to hemostasis. No bleeding complications occurred in the PTD group. Seven episodes of bleeding occurred in six patients given tPA; four were delayed 60-90 minutes after the procedure, one necessitated hospitalization, and two required additional therapies. Four of the 20 patients undergoing L&W with UK had minor puncture site bleeding during the procedure. The 3-month primary patency rates were 65%, 65%, and 60% for L&W with tPA, PTD, and L&W with UK, respectively (P = NS).

CONCLUSION

The 4-mg dose of tPA is effective but results in more bleeding complications and longer hemostasis times than mechanical thrombolysis with use of the PTD. Unlike in our experience with UK, bleeding complications with tPA were both major and delayed.

Successful clot lysis using low dose of streptokinase in 22 neonates with aortic thromboses

OBJECTIVE

To determine whether intravenous infusion of low dose of streptokinase was effective in lysing umbilical arterial catheter (UAC)-associated aortic thrombi.

METHOD

A prospective cohort study of 31 consecutive newborn infants with UAC-associated aortic thrombi which were detected by abdominal ultrasonography after removal of UAC. Twenty-two infants were treated with intravenous infusion of low dose (1000 U/h) streptokinase, while nine others were not treated due to various contra-indications. Thrombolysis occurred after a mean interval of 2.2 days (standard deviation (SD) = 1.8) in the treated infants. In the untreated infants, spontaneous thrombolysis occurred significantly later, after a mean interval of 16.9 days (SD = 14.7) (95% confidence intervals of difference between mean intervals - 26.0, - 3.4; P = 0.02). Only one treated infant developed mild bleeding directly attributed to streptokinase therapy.

CONCLUSION

Low dose streptokinase infusion was effective and safe in thrombolysing UAC-associated aortic thrombi.

[Intra-arterial thrombolysis of a basilar vascular accident during coronary angiography]

The authors report the case of a 67 year old man with a previous history of aortobifemoral arterial graft who had unstable angina after carotid endarterectomy. Coronary angiography by the right brachial artery was complicated by a cerebrovascular accident with a reactive coma, convulsions and respiratory problems. Selective angiography of the right vertebral artery showed an image of occlusive thrombosis of the basilar artery. In view of the clinical state and angiographic appearances, the authors decided on immediate intra-arterial thrombolysis with Urokinase which dissolved the clot and reestablished flow in the basilar artery, the cerebellar and posterior cerebral arteries. The outcome was favourable with immediate and good recovery of consciousness and hospital discharge on the sixth day without neurological or radiological sequellae. Cerebrovascular accident is a rare and potentially serious complication of left heart catheterisation which requires immediate cerebral angiography to determine the mechanism and propose an appropriate therapeutic approach.

[Simultaneous urokinase perfusion in renal artery and vein in a case of renal vein thrombosis]

We present he case of a young man with nephrotic syndrome, caused by membranous glomerulonephritis, who developed renal vein thrombosis with extension to the inferior vena cava is presented. Renal vein thrombosis was diagnosed by echo Doppler and confirmed by angio-CT scan. At the hospitalization the patient presented a severe left flank pain, edema of the lower limbs and painful left testicular tumefaction. The treatment consisted of: 1) systemic anticoagulation with sodic heparin, 2) placement of temporary vena cava filter through the right jugular vein, 3) direct thrombolysis into endocaval thrombus with early lysis of thrombus, and 4) renal thrombolysis with selective simultaneous renal artery and renal vein infusion of urokinase. Angiography performed after 24 hours of loco-regional thrombolysis showed complete lysis of renal thrombus; clinically there was a regression of left flank pain. We conclude that, face to renal vein thrombosis, thrombolytic treatment with simultaneous renal artery and renal vein perfusion is mandatory. Furthermore it is very important, in presence of caval extension of renal thrombus, to place a temporary vena cava filter before starting thrombolysis, considering the high risk of pulmonary embolism related to this pathology.

[Optimal thrombolysis]

Thrombolytic therapy is an established reperfusion strategy in acute myocardial infarction with proven long-term survival benefit. New thrombolytic agents including reteplase, lanoteplase, and tenecteplase have been developed to optimize thrombolytic therapy. With respect to efficacy the new thrombolytic agents show mortality equivalent to front-loaded alteplase, the present gold standard of thrombolytic therapy. With respect to ease of application there are advantages because third generation agents can be given as a single or double bolus instead of a bolus followed by an infusion. The most promising strategy to optimize coronary thrombolysis seems to be the combination of thrombolytic agents in reduced dose and GP IIb/IIIa blockers in full dose. The corresponding clinical trials (TIMI-14, SPEED, and INTRO-AMI) have also shown that there is an evolution in the surrogate end points for an optimal thrombolysis. In the past, optimal thrombolysis was associated with an open infarct-related coronary artery. A few years ago it was realized that TIMI-3 flow in the epicardial coronary artery was associated with the best results. Presently, normal myocardial microcirculation is regarded an additional prerequisite for further reduced mortality in acute myocardial infarction.

Extent of ST-segment deviation in the single ECG lead of maximum deviation present 90 or 180 minutes after start of thrombolytic therapy best predicts outcome in acute myocardial infarction

In evolving myocardial infarction the extent of ST segment deviation reflects the existing ischemic myocardial injury and thus conveys very useful early prognostic information. In recent years, the sum of ST segment elevation resolution (sum STR) has been proven to be an excellent early prognostic indicator. However, the predictive power of sum STR has never been systematically compared with that of other methods of evaluation of ST segment deviation recovery. We, therefore, proposed to compare the prognostic power of ST segment changes evaluated by either sum STR or by ST segment resolution in only the one lead showing the maximal deviation (lead STR) or only by the existing ST segment deviation in the single ECG lead of maximum ST deviation present at a given time point after thrombolysis (lead STE).

METHODS AND RESULTS

In conjunction with the Intravenous nPA for Treatment of Infarcting Myocardium Early (InTIME) II Study, which compared mortality in patients with acute myocardial infarction randomized within 6 hours of symptom onset to receive either Lanoteplase or Alteplase, all 3593 German and Polish patients participated in an ST segment resolution substudy. A 12-lead ECG was recorded at baseline and at 90 and at 180 minutes after start of thrombolytic therapy. The areas under the receiver-operating characteristic (ROC) curves to compare the power to predict 30 day cardiac mortality for sum STR, lead STR, and lead STE were at 90 min 0.686, 0.714, and 0.761 (p < 0.002), and at 180 min 0.678, 0.703, and 0.755 (p < 0.001), respectively. In multivariate analysis lead STE was an independent predictor of outcome even when adjustment was made for sum STR, lead STR, and clinical variables. Cardiac mortality rates at 30 days for lead STE risk groups, classified as low, medium, or high (percent of patients in brackets), were at 90 min 1.0% (43%), 4.0% (32%), and 12.8% (25%), and at 180 min 1.5% (55%), 3.8% (31%), and 15.2% (14%), respectively.

CONCLUSIONS

Simple measurement of the ST segment deviation existing in the one ECG lead with the greatest deviation on the ECG recorded 90 or 180 minutes after thrombolysis enables the identification of the major subsets of patients who are either at very low or exceptionally high risk of mortality.

A randomized trial confirming the efficacy of reduced dose recombinant tissue plasminogen activator in a Chinese myocardial infarction population and demonstrating superiority to usual dose urokinase: the TUCC trial

BACKGROUND

Reports from Japan suggest effective myocardial infarction (MI) treatment in Asian patients with much lower doses of tissue plasminogen activators (tPA) than used in European and American regimens. Because increasing doses of fibrinolytics lead to increased bleeding complications, identification of patients who respond to reduced doses is of importance. We conducted a trial in the People's Republic of China in which reduced-dose recombinant tPA was compared with the standard local therapy, urokinase.

METHODS

Four hundred patients with acute MI within 12 hours of symptom onset were to be randomized to an 8-mg bolus of recombinant tPA followed by a 42-mg 90-minute infusion or 1.5 million units of urokinase as a 30-minute infusion. Patients received aspirin and heparin and underwent angiography to determine infarct artery patency 90 minutes after the start of therapy.

RESULTS

The Data and Safety Monitoring Board recommended premature termination after 342 patients were recruited. Infarct artery patency (grade 2 or 3) occurred in 79% of patients receiving recombinant tPA and in 53% of patients receiving urokinase (P <.001); Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow was 48% and 28%, respectively (P <.001). The higher-patency-rate recombinant tPA growth had better posttreatment left ventricular ejection fractions, 58.6% versus 54.7%, P <.01. Adverse events were infrequent and not significantly different in the 2 groups.

CONCLUSIONS

This study confirms that a substantially lower dose of recombinant tPA is effective in Asian patients compared with that required in Western patients even after consideration of body weight. Specific dose-response studies should be performed with fibrinolytic regimens to avoid overdosage with its attendant risks of excess bleeding.

Intravitreous injection of tissue plasminogen activator and gas in the treatment of submacular hemorrhage under various conditions

OBJECTIVE

To investigate the efficacy and safety of treating submacular hemorrhages secondary to age-related macular degeneration (ARMD) with intravitreous recombinant tissue plasminogen activator (rt-PA) and gas under various conditions.

DESIGN

Prospective, noncomparative case series.

PARTICIPANTS

Forty-three consecutive eyes of 42 patients with recent (range, 2-28 days) subfoveal hemorrhage secondary to ARMD were included in this study. The size of subretinal hemorrhage ranged from 0.25 to 30 disc areas.

METHODS

All patients were treated with intravitreous injections of rt-PA (50 microg) and sulfur hexafluoride (0.5 ml). Postoperative prone positioning was maintained for 24 to 72 hours. Patient follow-up ranged from 4 to 18 months (mean, 6 months).

MAIN OUTCOME MEASURES

Best and final postoperative visual acuity in relation to size and onset of hemorrhage, displacement of subretinal blood, and surgical complications.

RESULTS

Best postoperative visual acuity compared with preoperative visual acuity was improved two or more Snellen lines in 19 eyes (44%) and stable in 24 eyes (56%). Final visual acuity was improved two or more lines in 13 eyes (30%), stable in 26 (61%), and two or more lines worse in 4 eyes (9%). Duration of hemorrhage <or=14 days was associated with a better gain of lines of vision (P = 0.0058). Best postoperative acuity was maintained for an average of 4.2 months (range, 0.5-12 months). Overall, complete displacement of blood from under the fovea was achieved in 35 eyes (81%). Nine eyes (21%) developed recurrent hemorrhage, which required repeat treatment. In three patients (7%), a mild breakthrough vitreous hemorrhage was observed.

CONCLUSIONS

Our findings suggest that intravitreous injections of rt-PA and gas are of value for an improved and accelerated visual recovery in ARMD patients with submacular hemorrhage, although final visual outcome is often limited by the progression of the underlying ARMD. Patients with retinal hemorrhages of recent onset (<or=14 days) seem to have the most favorable results. A rapid displacement of submacular blood may reveal discrete choroidal neovascular membranes amenable to further treatment. The complication rate of this minimally invasive technique seems to be low.

Controlled release of clot-dissolving tissue-type plasminogen activator from a poly(L-glutamic acid) semi-interpenetrating polymer network hydrogel

With the aim of developing an effective therapeutic modality for treatment of thrombosis, a tissue-type plasminogen activator (t-PA)-loaded porous poly(L-glutamic acid) (PLGA) semi-interpenetrating polymer network (semi-IPN) hydrogel was developed as a possible local drug delivery system. Porous structure of hydrogel was essential in this system to yield a large surface area so that t-PA release could be facilitated. This semi-IPN hydrogel was prepared using the method of free-radical polymerization and crosslinking of polyethylene glycol (PEG)-methacrylate through the PLGA network. Sodium bicarbonate (NaHCO(3)) was added to function as a foaming agent under acidic conditions, rendering the semi-IPN hydrogel to be porous. While the added NaHCO(3) provided gas foam in the reaction mixture, the pH in the hydrogel increased to about 7 to 8, which stimulated the polymerization. The porous structure that was presented at both the surface and sublayer was stabilized during hydrogel formation and freeze-drying. The hydrogel thus prepared possessed a porous structure of 10-20 microm in diameter, as determined by scanning electron microscopy. Results showed that the above hydrogel preparation process did not significantly alter the specific activity of the entrapped t-PA with regard to plasminogen activation and fibrin clot lysis ability. The t-PA release from this semi-IPN hydrogel was examined by measuring the plasmin activity using the chromogenic substrate S-2251. Findings in this paper demonstrated that the porous structure of the hydrogel facilitated t-PA release when compared to the dense structure. Aside from the porous structure, other factors including the content of the crosslinker, PLGA and t-PA could all be varied to regulate t-PA release from the hydrogel. These results suggest that a porous PLGA semi-IPN hydrogel could potentially be a useful local delivery system to release active t-PA primarily at the site of a thrombus.

Jet and ultrasonic nebulization of single chain urokinase plasminogen activator (scu-PA)

Recent studies have indicated that the deposition of intra-alveolar fibrin may play a central role in the pathogenesis of acute respiratory distress syndrome (ARDS). Our aim was to study whether the indigenous fibrinolytic agent (urokinase) normally present in the alveoli can be administered locally by nebulization in a recombinant zymogen form as single chain urokinase plasminogen activator (scu-PA). We aimed to characterize the particle size distribution, drug output, and enzymatic activity of scu-PA after nebulization with a Ventstream jet nebulizer (Medic-Aid, Bognor Regis, UK) and a Syst'AM DP-100 ultrasonic nebulizer (Pulmolink, Kent, UK). The particle size distribution was measured with a laser diffraction method and the drug output was determined by collection on filters. The amount of protein on the filters was determined with the Lowry method, and the enzymatic activity after nebulization was measured with a microtiter fibrin plate assay. The mass median diameter (MMD) of the scu-PA aerosol generated with the ultrasonic nebulizer was 3.69 (3.53-3.83) microm and with the jet nebulizer 2.96 (2.91-3.03) microm (p < 0.001). The drug output from the two nebulizers did not differ between nebulizers (p = 0.054). Fibrinolytically active scu-PA was generated with both nebulizers, but in contrast to jet nebulization, ultrasonic nebulization caused partial inactivation of scu-PA (p < 0.001). In conclusion, nebulization of scu-PA with the jet nebulizer is superior to ultrasonic nebulization in terms of particle size distribution and preservation of fibrinolytic activity.

[GPIIb/IIIa blockers for optimizing thrombolysis in acute myocardial infarct]

BACKGROUND

Thrombolytic therapy is an established strategy for the treatment of acute myocardial infarction. GPIIB/IIIA BLOCKERS + MODERN THROMBOLYTIC AGENTS: At present, the most attractive development for optimizing thrombolytic therapy includes the use of GPIIb/IIIa blockers in combination with modern thrombolytic agents such as alteplase and reteplase. The review summarizes the available results of clinical studies using standard doses of thrombolytic agents (TAMI 8, IMPACT-AMI, and PARADIGM) or reduced dosages of thrombolytic agents (TIMI 14 and SPEED) for combination therapy. The review also focuses on the implications of the combination therapy for coronary angioplasty immediately following coronary thrombolysis.

ATTEMPTS: a heparin/protamine-based prodrug approach for delivery of thrombolytic drugs

The aim of this study is to develop a heparin/protamine-based prodrug system for the controlled delivery of enzyme such as tissue-type plasminogen activator (tPA). This approach, termed antibody targeted, triggered, electrically modified prodrug-type strategy (ATTEMPTS), would permit antibody-directed administration of inactive tPA, and allow a subsequent triggered release of the active tPA at the target site. Cation-modified tPA (mtPA) was attached to a heparin--antifibrin complex via ionic interaction. The active tPA can be subsequently released by the addition of protamine, a competitive heparin inhibitor. Anti-fibrin IgG was conjugated to heparin via an end-point attachment to form the heparin--antifibrin--complex which provides the targeting efficiency of the final heparin--mtPA complex. Cation-modification was performed either by chemical conjugation by linking (Arg)(7)Cys to tPA with N-succinimidy-3-(2-pyridyldithio) propionate or by recombinant DNA method. Results show that the chemical modification process did not significantly alter specific activity of tPA with regard to plasminogen activation, fibrin-binding ability, and response toward fibrinogen. Expressed modified tPA (EmtPA) produced by recombinant DNA methods retained the same catalytic activity of the parent tPA, as well as a dynamic catalytic behavior depending upon the presence of heparin and protamine. Both types of modified tPA, especially the mtPA demonstrated a significantly higher affinity toward heparin or heparin--antifibrin complex than native tPA. In addition, the complexes of mtPA--heparin did not yield any intrinsic clot lysis activity owing to the blockage of the active site of tPA by attached heparin. On the other hand, heparin-induced inhibition of both mtPA and EmtPA activity was reversed by adding protamine, as confirmed by chromogenic and in vitro clot lysis assays. These results suggested that a heparin/protamine-based tPA delivery system may be a useful tool to improve current thrombolytic therapeutic status, by both precisely regulating the release of active tPA and aborting the associated bleeding risk. Alternatively, this ATTEMPTS approach could also be used to deliver enzyme drugs while diminishing their associated toxic effects.

[Successful cardiopulmonary resuscitation with a high-dosage bolus injection of rt-PA after fulminant pulmonary embolism]

The fulminant pulmonary embolism is one of the most feared complications of hospitalized patients. A high percentage of those patients need resuscitation within a short period of time. In such cases, the thrombolysis is a quickly attained therapeutical alternative to pulmonary embolectomy. A 77-year-old man with a surgically managed femoral fracture who suffered a massive pulmonary embolism, had to be resuscitated on the 11th postoperative day. Because of the fast confirmation of the diagnosis with the ECG and transthoracical echocardiography, it was possible to initiate thrombolysis with a bolus of 100 mg rt-PA immediately after the beginning of cardiac arrest and resuscitation. After 20 min of cardiopulmonary resuscitation (CPR), the patient could be stabilized under high dosage of catecholamines. The patient survived after prolonged intensive care treatment without severe bleeding complications, neither did he present any neurological deficit. We conclude that in the case of massive pulmonary embolism with small chance of resuscitation, the high-dose bolus injection of rt-PA could enrich the therapeutical possibilities.

[Repeat thrombolysis in acute myocardial infarction]

During two years period (Jul. 97-Aug. 99) data of patients suffering from recurrent acute myocardial infarct within 6 days were compared by retrospective analysis. In this interval authors treated 58 patients with recurrent myocardial infarct. 22 patients were transmitted to a catheterisation lab, data of the other 36 patients were compared. There were two treatment groups: 18 patients received repeated thrombolysis (IT group), and 18 patients got conventional therapy (HT group). In the thrombolytic group 15 patients received streptokinase infusion again, and urokinase infusion was administred in 3 patients at second time. The patients were not transferred to a cath lab, because of their older ages (10 patients), or capacity problems (13 patients), or in absence of their signed consent (13 patients). Comparisons were made on the basis of non invasive diagnostic procedures (reperfusion signs suggested by ECGs and enzymatic changes, and left ventricular ejection fraction at discharge), bleeding rate, and frequency of recurring angina at the 3 months visit, and on the basis of mortality. Ejection fractions and reperfusion signs were better in the repeated thrombolytic group (time of maximal level ST elevation: IT 19.70 +/- 6.00 min, HT 23.17 +/- 5.15 min, p = 0.26 NS; T wave inversion time within six hours: IT 168 +/- 45.17 min, HT 170 +/- 58.99 min, p = 0.94; reperfusion arrhythmia: IT 7, HT 3, p = 0.15; CK peak time: IT 16.89 +/- 6.94 hour, HT 20.00 +/- 6.72 hour, p = 0.18 NS; CK-MB peak time: IT 12.22 +/- 7.19 hour, HT 16.67 +/- 6.17, hour, p = 0.55; > 3 x CK peak time: IT 14.18 +/- 6.03 hour, HT 20.00 +/- 7.37 hour, p = 0.06, > 3 x CK-MB peak time: IT 8.80 +/- 4.54 hour, HT 15.20 +/- 6.19 hour, p = 0.02, ECHO EF: IT 48.53 +/- 6.81%, HT 43.14 +/- 4.90%, p = 0.02, Isotope ventriculography EF: IT 50.87 +/- 5.45%, HT 44.57 +/- 4.89%, p = 0.003), however the bleeding rate was moderately higher (minor bleeding: IT 7, HT 3, p = 0.15, major bleeding: IT 3, HT 1). The frequency of ischemic episodes at 3-month visit, and 3-month mortality were similar in the two groups (episodes of angina: IT 2.00 +/- 1.57, HT 2.42 +/- 1.88, p = 0.55; mortality: IT 4, HT 6, p = 0.46). Repeated thrombolysis is an effective therapeutical tool in centres without cath lab--according to the risk-benefit ratio too--in the case of early repeated myocardial infarct.

Comparative efficacy of primary angioplasty with stent implantation and thrombolysis in restoring basal coronary artery flow in acute ST segment elevation myocardial infarction: quantitative assessment using the corrected TIMI frame count

Following thrombolysis and primary percutaneous transluminal coronary angioplasty (PTCA) for acute ST segment elevation myocardial infarction, basal flow in the culprit artery is known to influence prognosis. The purpose of this study was to determine if differences exist in basal flow in culprit and nonculprit coronary arteries in patients with acute ST segment elevation myocardial infarction who were treated with thrombolysis or primary PTCA with stent implantation. Twenty patients were randomized to thrombolysis (with recombinant tissue plasminogen activator) and 24 to primary PTCA with stent implantation within 3 hours of onset of acute ST segment elevation myocardial infarction. Coronary angiography was performed 90-120 minutes after thrombolysis or immediately after PTCA with stent implantation and again at 18-36 hours after intervention in both groups. Patients who failed to achieve thrombolysis in myocardial infarction (TIMI) grade 2 or 3 flow were excluded. The corrected TIMI frame count was used as the index of basal coronary artery flow. Early after intervention the mean corrected TIMI frame count in the culprit coronary artery was significantly lower in the primary PTCA with stent group (27.4 +/- 7.7 frames) than in the thrombolysis group (39.8 +/- 10 frames, p < 0.001). Eight thrombolysis patients (40%) and 20 primary PTCA patients (83%, p < 0.01) achieved TIMI grade 3 flow early after intervention. By 18-36 hours after intervention there were no significant differences in the mean correct TIMI frame count between the thrombolysis and primary PTCA with stent groups. There were no significant differences in the mean corrected TIMI frame count between these two groups in the nonculprit coronary artery, either early after intervention or at 18-36 hours. In successfully reperfused coronary arteries following acute ST segment elevation myocardial infarction, primary angioplasty with stent implantation reestablished TIMI grade 2 or 3 flow faster and more effectively than thrombolysis did.

[Thrombolysis of prosthetic heart valve thrombosis using recombinant tissue plasminogen activator (rt-PA) in infancy and childhood]

Thrombotic obstruction of a mechanical cardiac valve prosthesis requires urgent therapy. We report on the treatment of prosthetic valve thrombosis with recombinant tissue plasminogen activator (rt-PA) in three children at the age of 4, 10 and 18 months, in whom a St. Jude Medical prosthesis had been placed at the atrioventricular valve level 2 to 6 weeks earlier. The initial rt-PA dose was 0.4 mg/kg given over 15 min and followed by a continuous daily infusion of 1.6 to 2.0 mg/kg. In addition the patients received heparin (200 U/kg/d). Thrombolytic therapy was administered for a range of 4 to 28 days. The therapy was successful in the first case. The second child had four recurrent events of prosthetic valve thrombosis and the thrombolytic therapy was successful three times. However, the prosthesis had to be finally replaced. In the third case the thrombolytic therapy was only partially successful due to an organized thrombus requiring prosthesis replacement.

Biochemical and biophysical conditions for blood clot lysis

We have studied how pharmacological dissolution of blood clots was affected by clot retraction, the mode of transport of fibrinolytic agents into the clot and the thickness of the composite fibrin fibers. Retracted clots were resistant to fibrinolysis in a milieu without dissolved plasminogen, because the amount of fibrin-bound plasminogen in retracted clots was insufficient for successful clot lysis. In plasma containing plasminogen, retracted clots were successfully lysed with fibrin-specific plasminogen activators, but not with non-fibrin-specific activators. Preincubation of retracted clots in plasma increased their plasminogen content as well as their sensitivity to fibrinolysis. The rate of lysis was increased up to 100-times when plasminogen activator and plasminogen were introduced into cylindrical clots by pressure-induced bulk flow in comparison with diffusion alone. The magnitude of the increase was similar in retracted and nonretracted clots, but the absolute rate of lysis was faster in non-retracted clots. The influence of fibrin fiber thickness on fibrinolysis was studied by atomic force microscopy. The time to complete lateral section of fibers did not differ between thick and thin composite fibers, and the rate of diameter reduction was faster in thick fibers than in thin ones. Taken together our results suggest that lysis of retracted clots proceeds in circular stages: (a) activation of bound plasminogen followed by partial degradation of fibrin, (b) opening of new plasminogen-binding sites on partly degraded fibrin, (c) binding of plasminogen to the new binding sites which enhances the susceptibility of clots to lysis. Lysis is accelerated by bulk flow of plasminogen activator and plasminogen into clots in comparison to diffusion alone. Fibrinolysis of thick composite fibrin fibers proceeds more efficiently than lysis of thin fibers.

Early reperfusion assessment and repeated thrombolysis in acute myocardial infarction estimated by repeated standard electrocardiography. A randomised, double-blind, placebo-controlled pilot study

Thrombolytic therapy with streptokinase (SK) in acute myocardial infarction (AMI) does not result in early reperfusion in approximately 25% of patients. We hypothesized that early repeated thrombolysis with rt-PA in patients with early failed reperfusion would result in myocardial reperfusion. Fifty-nine AMI patients with a symptom delay of <6 h, treated with SK were included. ECG was taken on admission and after 90 and 180 min. An ST recovery of > or =25% at 90 min was interpreted as successful reperfusion. Sixteen patients had failed reperfusion at 90 min and were randomized to repeated thrombolysis with rt-PA or placebo. At 180 min from SK start, ST recovery was higher in the placebo group than in the rt-PA group (71 vs. 40%, p = 0.05). No serious bleeding complications were observed. Due to the limited sample size it was not possible to draw prominent conclusions.

Combined intraarterial/intravenous thrombolysis for acute ischemic stroke

BACKGROUND AND PURPOSE

The intravenous use of recombinant tissue-type plasminogen activator (rTPA) in acute ischemic stroke has been investigated in three large trials. Limited series have reflected outcome after local intraarterial thrombolysis (LIT) in the cerebral territory. The purpose of this study was to evaluate the safety and efficacy of combined intraarterial/intravenous thrombolysis using rTPA (actilyse) for acute ischemic stroke.

METHODS

Forty-five patients with acute onset of severe hemispheric stroke and without signs of major cerebral infarction on early CT scans were randomized by order of admission. Twelve patients were treated with 50 mg actilyse (maximal dose, 0.7 mg/kg); three had occlusion of the internal carotid artery and nine had occlusion of the middle cerebral artery. Thrombolysis was started by LIT and continued intravenously within 6 hours of stroke onset. Outcome, assessed after 1 and 12 months according to the modified Rankin scale (MRS), was considered good (MRS score, 0-3) for patients who were functionally independent and poor (MRS score, 4-5) for those who were dependent or had died.

RESULTS

In the thrombolysis group, outcome was good in eight patients at 1 month and in 10 patients at 12 months; in the control group, outcome was good in seven (21%) and 11 (33%) patients, respectively. Of the eight patients with a good outcome after thrombolysis, four had complete and one had partial recanalization. In the control group, the rate of intracerebral hemorrhage was 6%. Mortality at 1 month in the thrombolysis and control groups was 17% and 48%, respectively.

CONCLUSIONS

Combined intraarterial/intravenous thrombolysis with low-dose rTPA may be a safe and effective treatment for acute ischemic stroke within 6 hours in carefully selected patients.

Daily catheter-directed single dosing of t-PA in treatment of acute deep venous thrombosis of the lower extremity

The strong fibrin affinity of recombinant tissue plasminogen activator (rt-PA) theoretically obviates continuous infusion or replacement of t-PA after direct intrathrombic injection. This hypothesis led the authors to evaluate single daily catheter-directed injection of rt-PA as a thrombolytic treatment for acute deep vein thrombosis of the lower extremity. Once-daily injection of rt-PA was performed in large thrombosed veins (popliteal or larger) with use of pulse-spray catheters and in small thrombosed veins in patients' calves with use of 3-4-F coaxial catheters. Patients received only full systemic anticoagulation on his/her patient care unit. This dosing regimen has been tested in 10 patients (12 legs) with a maximum dose of 50 mg per leg per day. Extensive thrombolysis was achieved in nine patients and partial thrombolysis was achieved in one patient, at an average total dose of 106 mg of rt-PA per leg. Minor bleeding was seen in three patients and no transfusions were needed. Our technique and the rationale for this pilot study is the focus of this article.

Combination reperfusion therapy with abciximab and reduced dose reteplase: results from TIMI 14. The Thrombolysis in Myocardial Infarction (TIMI) 14 Investigators

Aims Abciximab has previously been shown to enhance thrombolysis and improve myocardial perfusion when combined with reduced doses of alteplase. The purpose of the reteplase phase of TIMI 14 was to evaluate the effects of abciximab when used in combination with a reduced dose of reteplase for ST-elevation myocardial infarction. Methods and Results Patients (n=299) with ST-elevation myocardial infarction were treated with aspirin and randomized to a control arm with standard dose reteplase (10+10 U given 30 min apart) or abciximab (bolus of 0.25 mg. kg(-1)and 12-h infusion of 0.125 microg. kg(-1). min(-1)) in combination with reduced doses of reteplase (5+5 U or 10+5 U). Control patients received standard weight-adjusted heparin (bolus of 70 U. kg(-1); infusion of 15 U. kg(-1). h(-1)), while each of the combination arms with abciximab and reduced dose reteplase received either low dose heparin (bolus of 60 U. kg(-1); infusion of 7 U. kg(-1). h(-1)) or very low dose heparin (bolus of 30 U. kg(-1); infusion of 4 U. kg(-1). h(-1)). The rate of TIMI 3 flow at 90 min was 70% for patients treated with 10+10 U of reteplase alone (n=87), 73% for those treated with 5+5 U of reteplase with abciximab (n=88), and 77% for those treated with 10+5 U of reteplase with abciximab (n=75). Complete (>/=70%) ST resolution at 90 min was seen in 56% of patients receiving a reduced dose of reteplase in combination with abciximab compared with 48% of patients receiving reteplase alone. Conclusions Reduced doses of reteplase when administered in combination with abciximab were associated with higher TIMI 3 flow rates than reported previously for reduced doses of reteplase without abciximab and were at least as high as for full dose reteplase alone

Superselective ophthalmic artery fibrinolytic therapy for the treatment of central retinal vein occlusion

AIM

To study the effect of superselective ophthalmic artery fibrinolysis as a treatment for central retinal vein occlusion (CRVO).

METHODS

Retrospective, university based single centre study. The charts of 26 eyes of 26 patients treated were reviewed. Among the 26 patients, there were nine cases of combined artery and vein occlusion, three cases of combined cilioretinal artery and CRVO, and 14 cases of classic CRVO. Complete preoperative and postoperative ophthalmological examination and fluorescein angiography were performed in all cases. The therapeutic procedure comprised the infusion of urokinase through a microcatheter into the ostium of the ophthalmic artery, via a femoral artery approach. The main outcome measure was the improvement in visual acuity 48 hours after the procedure.

RESULTS

Six eyes of six patients exhibited significant improvement in visual acuity immediately after the fibrinolysis procedure. Among them, four had a initial funduscopic appearance suggestive of combined occlusion of the central retinal artery (CRAO) and vein. For these patients, the visual benefit was maintained in the long term. Intravitreal haemorrhage occurred in two patients. There were no extraocular complications linked to the procedure.

CONCLUSIONS

Selective ophthalmic artery infusion of urokinase was followed by improvement in VA in six out of 26 cases of CRVO. Eyes with combined CRAO and CRVO with recent visual loss appeared to be the most responsive. This treatment did not prevent the occurrence of ischaemia in the failure cases. The efficacy of in situ fibrinolysis for treatment of CRVO needs to be further evaluated in a controlled study.

Argatroban and alteplase in patients with acute myocardial infarction: the ARGAMI Study

ARGAMI was designed to assess safety and efficacy of argatroban compared with heparin as adjunctive treatment to alteplase in the treatment of patients with acute myocardial infarction. ARGAMI consisted of an open-dose finding study (35 patients) followed by a placebo-controlled study with double dummy technique and 2:1 (argatroban:heparin) randomization. An argatroban dosage of 100 microg/kg bolus plus 3 microg/kg/min infusion for 72 hours was selected for the randomized study in which 82 patients were allocated to argatroban and 45 to heparin (5000 U intravenous bolus, 1000 U/h infusion). Patency of the infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow) after 90 minutes was obtained in 62 patients (76%) allocated to argatroban versus 37 patients (82%) allocated to heparin (p=ns). Angiograms after 24 hours and 5 to 10 days showed low reocclusion rates in both groups. Bleeding complications were observed in 16 patients allocated to argatroban (19.5%) and in 9 patients allocated to heparin (20.0%). One patient allocated to heparin suffered from hemorrhage stroke. Argatroban, given as adjunctive treatment to alteplase, is tolerated well in patients with acute myocardial infarction. Safety and efficacy of the combination alteplase and argatroban (with this dose regimen) are similar to those of alteplase and heparin.

Thrombolytic therapy for prosthetic valve thrombosis: short- and long-term results

BACKGROUND

Thrombolytic therapy (TT) has evolved as an alternative to surgery for prosthetic valve thrombosis (PVT), but its utility in patient management is still debated and the long-term results are not available.

METHODS

From 1990 through 1999, we treated 110 consecutive patients (52 men, mean age 35.4 +/- 10.8 years) of left-sided obstructive PVT (96 mitral, 14 aortic) with TT (streptokinase in 108, urokinase in 2) according to a specified protocol of prolonged infusion. Serial echo Doppler parameters were monitored in all patients to guide the duration of TT and to quantify its efficacy. Ninety of the 102 survivors of the index episode were followed up for a mean period of 31.3 +/- 27.8 months (range 1-112 months).

RESULTS

Complete hemodynamic response (on cinefluoroscopy and echo Doppler criteria) was seen in 90 (81.8%) episodes, partial response in 11 (10%), and failure in 9 (8.2%). The mean duration of TT was 42.8 +/- 20.4 hours. Five of the 7 patients who were initially seen in cardiogenic shock/overt pulmonary edema died during therapy. After these patients were excluded, the rate of complete response did not differ among patients with New York Heart Association class I/II (80%), class III (86.3%), or class IV (81.5%). The response rate also did not vary with the type, position of prosthesis, duration of symptoms, or time lag since surgery. There were 21 (19.1%) embolic episodes during therapy, including 6 strokes. These were significantly more frequent in patients with atrial fibrillation (AF) (odds ratio on multivariate analysis 2.3, 95% confidence interval 1.3-3.9, P =.01). On follow-up, there were 25 recurrences of PVT, of which 20 again received TT with a complete response in 14 (70%). At 5 years the actuarial survival was 85.2% and the event-free survival was 61.5%. The presence of chronic AF was a significant predictor of recurrence of PVT (odds ratio 2.2, 95% confidence interval 1.2-3.9, P =.008).

CONCLUSIONS

TT is effective in the majority of patients with PVT but is associated with a high rate of embolism, especially in patients with AF. Excluding patients with cardiogenic shock/overt pulmonary edema (in whom TT is largely ineffective), the success of TT does not vary with the New York Heart Association class, duration of symptoms, or other patient variables. The recurrence rates of PVT are high after even successful TT, especially in patients with AF.

Intravitreal injection of tissue plasminogen activator and gas bubble for treatment of subretinal hemorrhage in ARMD

BACKGROUND

Subretinal hemorrhage (SRH) can arise from any number of underlying etiologies and can stem from either the choroidal and/or retinal circulation. It is most commonly associated with age-related macular degeneration (ARMD), in which a choroidal neovascular membrane is the usual source of bleeding. Vision loss resulting from SRH can be secondary to toxic, tractional, and barrier effects from persistent blood. To minimize long-term visual loss from SRH, several treatment modalities have evolved over the past few years. The most-recent therapeutic techniques involve treatment with the thrombolytic agent tissue plasminogen activator The value of surgical removal of subretinal hemorrhage to improve visual outcome remains unsubstantiated, as definitive studies have not been completed.

CASE REPORT

A 73-year-old man manifested a 1-day history of decreased vision in his right eye. A large submacular hemorrhage had developed as a result of exudative age-related macular degeneration. Treatment included intravitreal injection of tissue plasminogen activator, followed by intravitreal injection of SF6 gas, which displaced the subretinal hemorrhage away from the fovea and resulted in clearance of the submacular blood. This case describes a new treatment for submacular hemorrhage secondary to ARMD.

CONCLUSIONS

Subretinal hemorrhage secondary to ARMD can cause significant permanent visual loss. A thorough understanding of the pathogenesis of vision loss and the treatment options available are essential in successful management of these patients. Intravitreal injection of tissue plasminogen activator and gas bubble may provide an effective treatment for subretinal hemorrhage in age-related macular degeneration.

Branch retinal artery occlusion in a young woman with Ménière's disease

An unusual case of a 32-year-old woman with branch retinal artery occlusion is presented. The patient was affected by Ménière's disease and had a history of occasional migraine headaches. A thorough clinical and laboratory investigation showed a high cholesterol level. Retinal arterial obstruction is rare in young people and it is difficult to establish the precise cause. The presumed multifactorial etiologic factors are discussed.

Combination of a direct thrombin inhibitor and a platelet glycoprotein IIb/IIIa blocking peptide facilitates and maintains reperfusion of platelet-rich thrombus with alteplase

We sought to determine the efficacy of the combination of argatroban, a direct thrombin inhibitor, and G4120, a platelet glycoprotein (GP) IIb/IIIa blocker, to enhance thrombolysis with alteplase. Platelet-rich thrombus in the rabbit arterial thrombosis model is relatively resistant to alteplase despite the addition of aspirin and heparin. The adjunctive use of either direct thrombin inhibitors or GP IIb/IIIa inhibitors in thrombolysis has been investigated with encouraging, but limited, success. The usefulness of combining both agents as adjunctive therapy to thrombolysis has not been fully explored. Following platelet-rich thrombus formation in the rabbit, argatroban (3 mg/kg), G4120 (0.5 mg/kg), G4120 plus heparin (200 U/kg), or G4120 plus argatroban were intravenously infused over 60 minutes. Alteplase was given as intravenous boluses (0.45 mg/kg) at 15-minute intervals up to 4 doses or until reperfusion. Blood flow and bleeding time were monitored for 2 hours. The combination of G4120 plus argatroban resulted in a persistent patency in 5 of 7 animals compared with 0 of 6 for argatroban alone (p=0.02), 1 of 6 for G4120 alone (p=0.08), and 2 of 6 for G4120 plus heparin (p=0.2). Although during the infusion the bleeding times were longer in the groups that received G4120 (26+/-7.7 minutes vs. 14+/-10 minutes, p<0.05), by the end of the experiment there were no statistically significant differences. Similarly, during the infusion the activated partial thromboplastin times (aPTT) was higher in groups that received heparin or argatroban (99+/-51 seconds vs. 32+/-7.6 seconds, p<0.001), but by the end of the experiment the aPTTs had returned to close to baseline in all groups except the G4120 plus heparin group. These results suggest that lysis of platelet-rich thrombus with alteplase requires the addition of both potent platelet and thrombin inhibitors. Specifically designed agents, G4120 and argatroban, are effective without additional increased risk for bleeding.

Short- and long-term results after thrombolytic treatment of deep venous thrombosis

OBJECTIVES

The goal of this study was to assess the short- and long-term efficacy of different thrombolytic therapy regimens in patients with leg or pelvic deep venous thrombosis (DVT).

BACKGROUND

It is unclear whether locoregional or systemic thrombolysis is superior in treating acute leg DVT or even whether lysis is more effective than anticoagulation therapy in preventing postthrombotic syndrome.

METHODS

A total of 250 patients averaging 40 years of age with acute DVT were randomized into five groups to receive full heparinization (1,000 IU/h) and compression treatment, with four groups also administered locoregional tissue plasminogen activator (20 mg/day) or urokinase (100,000 IU/day) or systemic streptokinase (3,000,000 IU daily) or urokinase (5,000,000 IU daily). All groups then received anticoagulation and compression treatment for one year. Primary efficacy criteria included the change after one year in the number of closed vein segments and the occurrence of postthrombotic syndrome.

RESULTS

Systemic thrombolytic therapy significantly reduced the number of closed vein segments after 12 months in patients with acute DVT compared with conventional treatment (p < 0.05). Postthrombotic syndrome also occurred with less frequency in systemically treated patients versus controls (p < 0.001). High-dose thrombolysis led to better rates of complete recanalization after seven days (p < 0.01) than locoregional lysis. However, 12 patients receiving thrombolysis (9 systemic, 3 local) suffered major bleeding complications; 9 patients on systemic treatment developed pulmonary emboli.

CONCLUSIONS

Systemic thrombolytic treatment for acute DVT achieved a significantly better short- and long-term clinical outcome than conventional heparin/anticoagulation therapy but at the expense of a serious increase in major bleeding and pulmonary emboli. Given the inherent risks for such serious complications, systemic thrombolysis, although effective, should be used selectively in limb-threatening thrombotic situations.

Percutaneous fibrin sheath stripping versus transcatheter urokinase infusion for malfunctioning well-positioned tunneled central venous dialysis catheters: a prospective, randomized trial

PURPOSE

To compare central dialysis catheter patency rates after stripping procedures with those after urokinase (UK) infusion.

MATERIALS AND METHODS

Fifty-seven tunneled catheters with either (i) flow rates less than 250 mL/min and established baseline flow rates > or = 300 mL/min or (ii) flow rates 50 mL/min less than higher established baseline flows were prospectively randomized to undergo stripping procedures (n = 28) or UK infusion (n = 29) at 30,000 U/h via each port concurrently, for a total 250,000 U. Success and patency were determined by dialysis at normal flow rates (> or = 300 mL/min) or at the previously established higher baseline rate. Flow rates were monitored weekly. Primary patency ended with catheter malfunction or removal. Kaplan-Meier survival analysis was used to construct survival curves.

RESULTS

In the stripping group, initial clinical success was 89% (25 of 28). The 15-, 30-, and 45-day primary patency rates were 75% (n = 20), 52% (n = 13), and 35% (n = 8), respectively. The median duration of additional function was 32 days (95% CI: 18-48 d). In the UK group, initial clinical success was 97% (28 of 29). The 15-, 30-, and 45-day primary patency rates were 86% (n = 21), 63% (n = 13), and 48% (n = 9), respectively. The median duration of additional patency was 42 days (95% CI: 22-153 d). The Wilcoxon test for equality detected no significant difference in the survival curves for the two treatment groups (P = .236).

CONCLUSION

There is no significant difference in time to primary patency between the two methods. Both allow temporary catheter salvage in most patients.

[Increased efficacy of thrombolytic therapy in acute myocardial infarction by improved properties of new thrombolytic agents]

Thrombolysis is a milestone in the therapy of acute myocardial infarction due to its ubiquitous availability and ease of application. The recombinant form of tissue-type plasminogen activator (rt-PA) has been proven to be superior over first generation fibrinolytic agents (streptokinase, urokinase, APSAC) with respect to efficacy and side effects and the front-loaded regimen has meanwhile become the "gold"-standard of thrombolytic therapy. Biochemically modified mutants of wild-type t-PA, e.g. r-PA (reteplase), n-PA (lanoteplase), and TNK-t-PA have altered biochemical and pharmacokinetic characteristics which make them more easy to use (as double or single bolus injection) and share a theoretical efficacy benefit. This article describes these specific characteristics focussing on clot-selectivity and PAI-1 resistance of the new mutants of wild-type t-PA and their possible clinical efficiency.