***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Treatment with heparin or streptokinase was allocated r and omly to 30 patients with life-threatening pulmonary embolism verified by angiography . Treatment was given for 72 hours and pulmonary angiography was repeated . There was significantly greater ( P < 0·001 ) evidence of thrombolysis in those patients treated with streptokinase compared with those treated with heparin .  The reduction of systolic and mean pulmonary arterial pressures was also significantly greater ( P < 0·05 and P < 0·02 respectively ) in the streptokinase group . Seven patients failed to complete 72 hours of the trial treatment : five successfully underwent pulmonary embolectomy . Six of these “ failures ” had initial pulmonary angiographic scores of 24 or more and systemic systolic blood pressure recordings of 100 mm Hg or less . Patients with these features should probably be considered for pulmonary embolectomy as the initial treatment . A febrile reaction commonly occurred in the streptokinase group ; otherwise side effects were no more common than in the heparin group Dissolution of pulmonary emboli with heparin and urokinase is ascribed , respectively , to anticoagulation and fibrinolysis . Since truly independent assessment of these effects in man is lacking , we administered each drug alone . Fibrinogen and plasminogen plasma levels and the resolution of pulmonary emboli were measured in three r and omized groups of 10 patients each : groups A and C infused with small repeated doses of urokinase and a large single dose of urokinase , respectively , and group B who received heparin . After 6 h of treatment , fibrinogen fell in all the groups , while , after 12 h , remained equally reduced in groups A and B and declined further in group C. Plasminogen behaved similarly . Up to 60 h , statistical analysis showed that these effects were related to timing and amounts of urokinase and heparin infusion . These observations suggest that heparin may induce a lytic state . As to signs of pulmonary emboli resolution , no differences between groups were found in lung perfusion and gas exchange recovery at any time ( from 1 day to 1 year ) and in pulmonary artery pressure reduction at 1 week . The greater angiographic and scintigraphic recovery observed with urokinase , versus heparin alone , after 1 day of treatment in the Urokinase Pulmonary Embolism Trial may be ascribed to a synergistic effect with urokinase of heparin administered during the diagnostic work-out . The indications of heparin and urokinase should be evaluated in the light of these results BACKGROUND The role of echocardiographic right ventricular ( RV ) dysfunction in predicting clinical outcome in clinical ly stable patients with pulmonary embolism ( PE ) is undefined . In this study , we assessed the prevalence and clinical outcome of normotensive patients with RV dysfunction among a broad spectrum of PE patients . METHODS AND RESULTS This prospect i ve clinical outcome study included cohort of 209 consecutive patients ( age , 65+/-15 years ) with documented PE . Acute RV dysfunction was diagnosed in the presence of > /=1 of the following : RV dilatation ( without hypertrophy ) , paradox septal systolic motion , and Doppler evidence of pulmonary hypertension . Four groups were identified : 28 patients presenting with shock or cardiac arrest ( 13 % ) , 19 hypotensive patients without shock ( 9 % ) , 65 normotensive patients with echocardiographic RV dysfunction ( 31 % ) , and 97 normotensive patients without RV dysfunction ( 47 % ) . Among normotensive patients with RV dysfunction , 6 ( 10 % ) developed PE-related shock after admission : 3 of these patients died , and 3 were successfully treated with thrombolytic agents . In comparison , none of the 97 normotensive patients without RV dysfunction developed shock or died as a result of PE . CONCLUSIONS A significant proportion ( 31 % ) of normotensive patients with acute PE presents with RV dysfunction ; these patients with latent hemodynamic impairment have a 10 % rate of PE-related shock and 5 % in-hospital mortality and may require aggressive therapeutic strategies . Conversely , normotensive patients without echocardiographic RV dysfunction have a benign short-term prognosis . Thus , early detection of echocardiographic RV dysfunction is of major importance in the risk stratification of normotensive patients with acute PE BACKGROUND The effect of alteplase versus heparin in pulmonary embolism has not been studied extensively with serial pulmonary angiograms . OBJECTIVES The aim of this r and omized , open trial was to evaluate the efficacy and safety of alteplase followed by heparin , versus heparin alone , in 36 patients with angiographically documented pulmonary embolism . METHODS Twenty patients were allocated r and omly to a 2-h infusion of alteplase ( 10 mg bolus , then 90 mg over 2 h ) followed by heparin ; the other 16 patients were given intravenous heparin at a continuous infusion rate of 1,750 IU/h . RESULTS The vascular obstruction , assessed by the Miller index at pulmonary angiography , decreased significantly in alteplase-treated patients ( p less than 0.01 ) from a baseline of 28.3 + /- 2.9 to a value of 24.8 + /- 5.2 2 h after the start of infusion ; in the heparin group there was no change ( from 25.3 + /- 5.3 to 25.2 + /- 5.4 ) . Mean pulmonary artery pressure decreased significantly from a baseline of 30.2 + /- 7.8 mm Hg to 21.4 + /- 6.7 in the alteplase group and increased in the heparin group ( from 22.3 + /- 10.5 to 24.8 + /- 11.2 mm Hg ) . For a subset of patients , lung scans were performed at baseline and on days 7 and 30 . There were no differences between the two groups in the follow-up lung scans , but there were significant decreases from the baseline values . Bleeding occurred in 14 of 20 alteplase-treated patients and in 6 of 16 in the heparin group ( p = NS ) . There were three major bleeding episodes in the alteplase group and two in the heparin group . Two patients died after fibrinolysis ( one of acute renal failure after cardiac tamponade and one of cardiac arrest after cerebral hemorrhage ) and one patient in the heparin group died of recurrent pulmonary embolism . CONCLUSIONS Alteplase result ed in a greater and faster improvement of the angiographic and hemodynamic variables compared with heparin . However , the high frequency of bleeding observed with alteplase in this trial suggests that patients should be carefully selected before thrombolytic therapy is given BACKGROUND Pulmonary embolism is a potentially fatal disorder . Information about the outcome of clinical ly recognized pulmonary embolism is sparse , particularly given that new treatments for more seriously ill patients are now available . METHODS We prospect ively followed 399 patients with pulmonary embolism diagnosed by lung scanning and pulmonary angiography , who were enrolled in a multicenter diagnostic trial . We review ed all hospitalizations , all new investigations of pulmonary embolism , and all deaths among the patients within one year of diagnosis . RESULTS Of the 399 patients , 375 ( 94 percent ) received treatment for pulmonary embolism , usually conventional anticoagulation . Only 10 patients ( 2.5 percent ) died of pulmonary embolism ; 9 of them had clinical ly suspected recurrent pulmonary embolism . Clinical ly apparent pulmonary embolism recurred in 33 patients ( 8.3 percent ) , of whom 45 percent died during follow-up . Ninety-five patients with pulmonary embolism ( 23.8 percent ) died within one year . The conditions associated with these deaths were cancer ( relative risk , 3.8 ; 95 percent confidence interval , 2.3 to 6.4 ) , left-sided congestive heart failure ( relative risk , 2.7 ; 95 percent confidence interval , 1.5 to 4.6 ) , and chronic lung disease ( relative risk , 2.2 ; 95 percent confidence interval , 1.2 to 4.0 ) . The most frequent causes of death in patients with pulmonary embolism were cancer ( in 34.7 percent ) , infection ( 22.1 percent ) , and cardiac disease ( 16.8 percent ) . CONCLUSIONS When properly diagnosed and treated , clinical ly apparent pulmonary embolism was an uncommon cause of death , and it recurred in only a small minority of patients . Most deaths were due to underlying diseases . Patients with pulmonary embolism who had cancer , congestive heart failure , or chronic lung disease had a higher risk of dying within one year than did other patients with pulmonary embolism STUDY OBJECTIVES To assess the potential benefit of thrombolysis in patients with massive pulmonary embolism ( PE ) with stable hemodynamics and right ventricular dysfunction . DESIGN Retrospective , cohort study . SETTING University-based , tertiary referral medical center . PATIENTS One hundred fifty-three consecutive patients with massive PE from January 1992 to December 1997 treated with heparin or thrombolysis .  MEASUREMENTS AND RESULTS Massive PE was confirmed by perfusion lung scan or pulmonary angiography . Right ventricular dysfunction was assessed by echocardiography ( right ventricular/left ventricular [ RV/LV ] diastolic diameter ratio > 0.6 ) in all patients . In order to study a homogeneous population , 64 patients treated with thrombolysis ( group 1 ) were matched on baseline RV/LV diameter ratio to 64 patients treated with heparin ( group 2 ) . Perfusion lung scan was repeated at day 7 to day 10 . Mean relative improvement in perfusion lung scans was higher in group 1 than group 2 ( 54 % vs 42 % , respectively ) . PE recurrences were the same in both groups ( 4.7 % ; n = 3 ) . There were no bleeding complications and no deaths in group 2 . Conversely , in group 1 , 15.6 % ( n = 10 ) of patients suffered from bleeding ( 4.7 % ; n = 3 with intracranial bleeding ) and 6.25 % ( n = 4 ) of them died . CONCLUSIONS The results of this monocenter registry do not support the indication for thrombolysis in patients suffering from massive PE with stable hemodynamics and right ventricular dysfunction . Appropriate therapy in such patients still remains unknown . Further prospect i ve r and omized trials should be performed To test the efficacy of thrombolytic therapy in massive pulmonary embolism , we conducted a prospect i ve r and omized controlled trial . Eight patients were r and omized to receive either 1,500,000 IU of streptokinase in 1 hour through a peripheral vein followed by heparin or heparin alone . All patients had major risk factors for deep vein thrombosis ( DVT ) and were considered to have high clinical suspicion for pulmonary embolism ( PE ) . At baseline all patients had a similar degree of systemic arterial hypotension , pulmonary arterial hypertension , and right ventricular dysfunction . The time of onset of cardiogenic shock in both groups was comparable ( 2.25 ±0.5 hours in the streptokinase group and 1.75 ±0.96 hours in the heparin group ) . The four patients who were r and omized to streptokinase improved in the first hour after treatment , survived , and in 2 years of follow-up are without pulmonary arterial hypertension . All four patients treated with heparin alone died from 1 to 3 hours after arrival at the emergency room ( p=0.02 ) . Post-thrombolytic therapy the diagnosis of PE was sustained in the streptokinase group by high probability V/Q lung scans and proven DVT . A necropsy study performed in three patients in the heparin group showed massive pulmonary embolism and right ventricular myocardial infa rct ion , without significant coronary arterial obstruction . The results indicate that thrombolytic therapy  reduces the mortality rate of massive acute pulmonary embolism Experiments in animals have demonstrated that recombinant tissue plasminogen activator ( rt-PA ) produces continuing thrombolysis after it is cleared from the circulation and that thrombolysis is both increased and accelerated , and bleeding is reduced when rt-PA is administered over a short period . In previous studies in patients with thrombotic disease , rt-PA has been shown to be an effective thrombolytic agent when administered by continuous infusion over a period between 90 minutes and 8 hours . To determine whether a short course regimen of rt-PA can achieve thrombolysis , a double-blind r and omized trial has been conducted in which patients with objective ly established acute symptomatic pulmonary embolism who were receiving heparin were allocated to either a 2-minute infusion of rt-PA at a dose of 0.6 mg/kg  ( 33 patients )  or saline placebo ( 25 patients ) . Perfusion lung scanning was used to assess the change in pulmonary perfusion at 24 hours and seven days post- study drug administration . Thirty-four percent of the rt-PA patients had a greater than 50 percent resolution in the perfusion defect at 24 hours compared to 12 percent of placebo 
    Output:
    
Because 30 % to 50 % of patients with PE present with echocardiographic evidence of RV dysfunction , the administration of a thrombolytic treatment toallof them would have significant implication s. The arguments for thrombolysis in such patients are essentially the following:(1)RVdysfunctionisastrong prognostic factor in patients with acute PE ; ( 2 ) the ability of thrombolytic agents to improve pulmonary reperfusion and enhanceRVfunction should translate into clinical benefit ; and ( 3 ) results of several studies have suggestedabeneficialeffectof thrombolysis in patients with acute PE and RV dysfunction .