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THROMBOLYSIS. Acute MI. Reducing delay is our major challenge. Delay in context : Delay thrombolysis by 1 hour = 21 deaths/1000 patients in one month (and probably as many again die in 2 years) Rawles 1998. How to establish reperfusion. Thrombolysis Coronary Angioplasty ( PTCA).
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Acute MI Reducing delay is our major challenge • Delay in context : • Delay thrombolysis by 1 hour = 21 deaths/1000 patients in one month (and probably as many again die in 2 years) • Rawles 1998
How to establish reperfusion • Thrombolysis • Coronary Angioplasty ( PTCA)
AAC/AHA Guidelines for Thrombolysis • All patients who have symptoms suggesting AMI • Within 12 hours of onset of symptoms • ECG changes of AMI (STEMI, new BBB) • No contraindications
Thrombolysis : What to give ? • Streptokinase : 1.5MU in 100 ml. 5% Dextrose/0.9% saline over 60 mins. • tPA : 15 mg bolus , followed by 50mg over 60 mins.& residual 35 mg over 30 mins. • Reteplase : 10 IU bolus, then 10 IU after 30 mins. • Tenecteplase : 30-50mg IV bolus • Door-to-needle time – 30 min
Thrombolytics Streptokinase AlteplaseReteplaseTenecteplase 1.5 MU over Up to 100 mg 10 U IV x 2 30-50 mg 30-60 min eachin 90 min over 2 min Patency 90 min 50% 75% 60-70% 75%
Problems with thrombolysis • Only 30 % pts.recieve it • Patency rate 66% (Tenecteplase) 63% (Reteplase) ; 54% (tPA); ! 30% (STK) • 30% reocclude in 3 months • Not for haemodynamically unstable pts. • Residual stenosis
Time to ThrombolysisInt J Cardiol 1995; 49: 33-37 EMIP MITI GREAT Benefit Gradient 23 / 1000 / Hour
2008 guidelines ACC/AHA • The use of prehospital 12-lead electrocardiography is encouraged to increase the efficiency of care for STEMI.
Time saved by prehospital thrombolysis ( min.) • McNeil 68 • Castaigne 60 • Barbash 40 • Schofer 43 • GREAT 130 • McAleer 34 • EMIP 55 • MITI 33
Feasibility of prehospital thrombolysis • For whom ? :STEMI / New BBB No age limit • What setting ? :home to hospital>90 min • Major problems : VF (2.5 vs 1.6%) Shock ( 6.3 vs 3.9%) • Which agent?: Antistreplase; Reteplase • Skills / Equipment?: Trained paramedic, 12-lead ECG, well-developed emergency medical services
Thrombolysis : do not use • Active internal bleeding • CVA ~ 2 months • Known CNS neoplasm • Recent trauma / Major surgery ~ 2 wks. • Pregnancy • BP > 180 / 110 • Prolonged CPR > 5-10 mins
Pulmonary EmbolismTHROMBOLYTIC THERAPY • Thrombolysis • (with iv Steptokinase, Urokinase, rTPA) leads to • Quicker resolution of clot . • Reverse RT. Heart failure & Improved haemodynamics • Probably improved long term outcomes • Effective for up to 10-14 days after symptoms • But NOT • Reduced mortality • Reduced PE recurrence
Dose Schedule in PE • 1. STK - IV bolus 250,000 U over 30‘ followed by infusion 100,000U/hr for 12-24hrs • 2. rtPA – IV bolus of 15 mg in 10’ followed by 85 mg in next 2hrs <total= 100mg> to be followed by heparin on completion of rtPA. • 3. UK - 4400 U/kg for 10’ by 4400 U/kg/hr for 24hrs. • Drawbacks- danger of severe & often fatal bleeding: ICH 1-3% , failed thrombolysis 8-10%
Acute Ischaemic Stroke: Thrombolysis • rtPA is the treatment of choice for thrombolysis in acute stroke. rtPA is the treatment of choice for patients who present within 3(4.5) hours of the onset of stroke symptoms. • Treatment with streptokinase is not recommended, and reteplase, urokinase, and other thrombolytic agents should not be used outside of the setting of a clinical trial. • Intra-arterial thrombolysis may be used for patients with occlusions of the middle cerebral artery who can be treated within 6 hours of symptom onset.
Acute IschaemicStroke:IVtPA • 0.9mg/Kg max 90mg infused over 60 min • 10% dose administered as initial IV bolus over 1 min • Following tPA no aspirin, heparin, or warfarin for 24 hours