Warfarin After Anterior ST-Elevation Myocardial Infarction

NCT ID: NCT00662467

Last Updated: 2008-04-21

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

20 participants

Study Classification

INTERVENTIONAL

Study Start Date

2006-11-30

Study Completion Date

2008-01-31

Brief Summary

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Following severe heart attacks involving the front wall of the heart (anterior myocardial infarction), patients are at risk of developing blood clots in the main pumping chamber that can cause a stroke. In the past, studies have shown that a blood thinner (warfarin) can decrease the risk of stroke and clot formation if administered to patients after an anterior myocardial infarction.

However, in today's current practice, certain heart attack patients are commonly treated with two blood-thinning medications (aspirin and clopidogrel) to prevent recurrent heart attacks.

Thus, a clinical problem is created as physicians are not clear how to treat patients after an anterior myocardial infarction who are at risk of a clot but require aspirin and clopidogrel to keep their blood vessels open. Adding warfarin to the combination of aspirin and clopidogrel will possibly decrease the risk of stroke but increase the risk of bleeding. Currently, there is no good evidence to help guide physicians. As demonstrated by a survey done at the Hamilton Health Sciences, there is a fifty/fifty split between physicians who use dual (aspirin and clopidogrel) versus triple (aspirin, clopidogrel, and warfarin) therapy in the treatment of similar patients as described above.

The purpose of this study is to address the bleeding and stroke complications in patients after a severe anterior myocardial infarction. Half of the eligible patients will receive dual therapy and half will receive triple therapy. We will compare the incidence of stroke, blood clots, and bleeding complications between the two groups at 3 months.

Detailed Description

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Rationale:

Left ventricular mural thrombus (LVT) remains a common complication after anterior ST-elevation myocardial infarction (STEMI) with a reported incidence ranging from 12- 17%. Previous studies from the pre-thrombolytic era have shown that warfarin therapy significantly reduces the incidence of LVT and embolic events in patients post anterior STEMI. However, the risk/benefit ratio of warfarin therapy in the setting of early revascularization and dual antiplatelet therapy with aspirin and clopidogrel remains unknown.

Purpose:

To compare the incidence of death, MI, stroke, embolic events, LVT, and bleeding complications at 3 months in patients with an anterior STEMI and ejection fraction less than 40% treated with ASA and clopidogrel alone versus those treated with aspirin, clopidogrel, and warfarin (triple therapy group).

Sample Size:

This is a pilot project to help establish the feasibility of conducting a full scale externally funded study. As such sample size calculations are not applicable. The primary aim of the study is to determine the safety and feasibility of conducting a large-scale trial, and this pilot project in not expected to reveal a statistically significant difference between the 2 groups.

Design/Methodology:

All patients will be randomized to either aspirin and clopidogrel alone or to triple therapy with aspirin, clopidogrel and warfarin. The randomization process will be centralized and computer generated. Patients with a clear indication for oral anticoagulation such as atrial fibrillation, LV thrombus, mechanical heart valve, or DVT/PE will not undergo randomization but will be followed as part of a registry of patients on triple therapy. All patients will remain on the allocated therapy for 3 months at which time outcomes will be determined.

Study interventions:

Patients will be treated with either ASA and clopidogrel alone (dual therapy) or with aspirin, clopidogrel and warfarin (triple therapy) in combination for 3 months. Patients in the triple therapy arm will be bridged with intravenous unfractionated heparin, low molecular weight heparin, or fondaparinux until their INR is therapeutic, and will be followed by the thrombosis service for the duration of the study.

Conditions

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Myocardial Infarction

Keywords

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Myocardial Infarction Hemorrhage Thromboembolism Clopidogrel Aspirin Warfarin

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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1

aspirin and clopidogrel

Group Type ACTIVE_COMPARATOR

aspirin + clopidogrel

Intervention Type DRUG

Dual therapy

2

aspirin, clopidogrel, and warfarin

Group Type EXPERIMENTAL

aspirin + clopidogrel + warfarin

Intervention Type DRUG

Triple therapy

Interventions

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aspirin + clopidogrel

Dual therapy

Intervention Type DRUG

aspirin + clopidogrel + warfarin

Triple therapy

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Anterior STEMI
* An ejection fraction less than 40% as per initial LV angiography or echocardiogram
* Randomization possible within hospital admission if anticoagulated with no interruption \> 24 hours
* Patient able and willing to give informed consent to participate in this trial

Exclusion Criteria

* history of intracranial hemorrhage
* history of GI bleed last 6 months
* hemoglobin \< 90 g/L
* platelet count \< 100 x 10exp9/L
* ischemic stroke last 30 days
* intracranial tumor or aneurysm
* significant pericardial effusion
* severe renal failure (creatinine \> 250 mmol/L).
Minimum Eligible Age

18 Years

Maximum Eligible Age

85 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Hamilton Health Sciences Corporation

OTHER

Sponsor Role lead

Responsible Party

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McMaster University

Principal Investigators

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Jon-David R Schwalm, MD, FRCPC

Role: PRINCIPAL_INVESTIGATOR

McMaster University

Mayraj Ahmad, MD, FRCPC

Role: PRINCIPAL_INVESTIGATOR

McMaster University

Locations

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Hamilton Health Sciences-Hamilton General Hopsital

Hamilton, Ontario, Canada

Site Status

Countries

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Canada

References

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Nihoyannopoulos P, Smith GC, Maseri A, Foale RA. The natural history of left ventricular thrombus in myocardial infarction: a rationale in support of masterly inactivity. J Am Coll Cardiol. 1989 Oct;14(4):903-11. doi: 10.1016/0735-1097(89)90463-4.

Reference Type BACKGROUND
PMID: 2794276 (View on PubMed)

Asinger RW, Mikell FL, Elsperger J, Hodges M. Incidence of left-ventricular thrombosis after acute transmural myocardial infarction. Serial evaluation by two-dimensional echocardiography. N Engl J Med. 1981 Aug 6;305(6):297-302. doi: 10.1056/NEJM198108063050601.

Reference Type BACKGROUND
PMID: 7242633 (View on PubMed)

Meltzer RS, Visser CA, Fuster V. Intracardiac thrombi and systemic embolization. Ann Intern Med. 1986 May;104(5):689-98. doi: 10.7326/0003-4819-104-5-689.

Reference Type BACKGROUND
PMID: 3516044 (View on PubMed)

Kupper AJ, Verheugt FW, Peels CH, Galema TW, Roos JP. Left ventricular thrombus incidence and behavior studied by serial two-dimensional echocardiography in acute anterior myocardial infarction: left ventricular wall motion, systemic embolism and oral anticoagulation. J Am Coll Cardiol. 1989 Jun;13(7):1514-20. doi: 10.1016/0735-1097(89)90341-0.

Reference Type BACKGROUND
PMID: 2723267 (View on PubMed)

Chiarella F, Santoro E, Domenicucci S, Maggioni A, Vecchio C. Predischarge two-dimensional echocardiographic evaluation of left ventricular thrombosis after acute myocardial infarction in the GISSI-3 study. Am J Cardiol. 1998 Apr 1;81(7):822-7. doi: 10.1016/s0002-9149(98)00003-4.

Reference Type BACKGROUND
PMID: 9555769 (View on PubMed)

Nayak D, Aronow WS, Sukhija R, McClung JA, Monsen CE, Belkin RN. Comparison of frequency of left ventricular thrombi in patients with anterior wall versus non-anterior wall acute myocardial infarction treated with antithrombotic and antiplatelet therapy with or without coronary revascularization. Am J Cardiol. 2004 Jun 15;93(12):1529-30. doi: 10.1016/j.amjcard.2004.02.066.

Reference Type BACKGROUND
PMID: 15194027 (View on PubMed)

Stratton JR, Lighty GW Jr, Pearlman AS, Ritchie JL. Detection of left ventricular thrombus by two-dimensional echocardiography: sensitivity, specificity, and causes of uncertainty. Circulation. 1982 Jul;66(1):156-66. doi: 10.1161/01.cir.66.1.156.

Reference Type BACKGROUND
PMID: 7083502 (View on PubMed)

Vaitkus PT, Barnathan ES. Embolic potential, prevention and management of mural thrombus complicating anterior myocardial infarction: a meta-analysis. J Am Coll Cardiol. 1993 Oct;22(4):1004-9. doi: 10.1016/0735-1097(93)90409-t.

Reference Type BACKGROUND
PMID: 8409034 (View on PubMed)

Weinreich DJ, Burke JF, Pauletto FJ. Left ventricular mural thrombi complicating acute myocardial infarction. Long-term follow-up with serial echocardiography. Ann Intern Med. 1984 Jun;100(6):789-94. doi: 10.7326/0003-4819-100-6-789.

Reference Type BACKGROUND
PMID: 6721297 (View on PubMed)

Chen ZM, Jiang LX, Chen YP, Xie JX, Pan HC, Peto R, Collins R, Liu LS; COMMIT (ClOpidogrel and Metoprolol in Myocardial Infarction Trial) collaborative group. Addition of clopidogrel to aspirin in 45,852 patients with acute myocardial infarction: randomised placebo-controlled trial. Lancet. 2005 Nov 5;366(9497):1607-21. doi: 10.1016/S0140-6736(05)67660-X.

Reference Type BACKGROUND
PMID: 16271642 (View on PubMed)

Sabatine MS, Blake GJ, Drazner MH, Morrow DA, Scirica BM, Murphy SA, McCabe CH, Weintraub WS, Gibson CM, Cannon CP. Influence of race on death and ischemic complications in patients with non-ST-elevation acute coronary syndromes despite modern, protocol-guided treatment. Circulation. 2005 Mar 15;111(10):1217-24. doi: 10.1161/01.CIR.0000157733.50479.B9.

Reference Type BACKGROUND
PMID: 15769761 (View on PubMed)

Antman EM, Anbe DT, Armstrong PW, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr, Alpert JS, Anderson JL, Faxon DP, Fuster V, Gibbons RJ, Gregoratos G, Halperin JL, Hiratzka LF, Hunt SA, Jacobs AK; American College of Cardiology; American Heart Association Task Force on Practice Guidelines; Canadian Cardiovascular Society. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). Circulation. 2004 Aug 31;110(9):e82-292. No abstract available.

Reference Type BACKGROUND
PMID: 15339869 (View on PubMed)

Other Identifiers

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06-281

Identifier Type: -

Identifier Source: org_study_id