Reperfusion therapy

Restoring bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. flow in a coronaryRelating to the arteries supplying the heart itself. arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. can be done in one of two ways: by giving 'clot-busting' drugs, which are called thrombolyticsA medication that breaks up blood clots., or by a procedure called angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility. (also known as percutaneous coronary interventionAngioplasty: the mechanical widening or clearing of a narrowed or obstructed blood vessel.; percutaneous simply means 'through the skin'). Angioplasty involves clearing out the coronaryRelating to the arteries supplying the heart itself. arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. mechanically, rather than dispersing the clot using medication.

Both options are effective,[1] and there has been much debate about which path is best initially.[2,4]

Thrombolysis

Coronary thrombolysisBreaking up a blood clot by administering medications called thrombolytics. uses 'clot-busting' drugs to help to restore bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. flow through the coronaryRelating to the arteries supplying the heart itself. arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood.. Given early, this limits any damage to the heart muscleTissue made up of cells that can contract to bring about movement. and improves the person's chances of survival.

When successful, thrombolysisBreaking up a blood clot by administering medications called thrombolytics. restores bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. flow, relieves pain and resolves ECGAbbreviation for electrocardiogram, a tracing of the electrical activity of the heart to help in the diagnosis of heart disease. changes. The drugs are given intravenously and are most effective when administered within a few hours of symptoms starting. The accepted 'window' for giving thrombolytic therapy is usually at most 12 hours from the onset of symptoms.[1,3] After receiving thrombolysisBreaking up a blood clot by administering medications called thrombolytics., many patients will go on to have angiographyX-ray imaging of the blood vessels following the injection of a dye to improve visibility..

In around 10-20 per cent of people given thrombolysisBreaking up a blood clot by administering medications called thrombolytics., the affected bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. vessel may become blocked again later on.

The main adverse effect resulting from thrombolytic therapy is bleeding, which can, in extreme cases, result in a stroke. Because of this, the benefits of thrombolysisBreaking up a blood clot by administering medications called thrombolytics. must be weighed up against its risks before it can be given. For example, the risk of bleeding is increased in people who have a history of active peptic ulcerationAn ulcer caused by the erosion of the lining of the gastrointestinal tract by digestive juices.. People who have had a stroke in the past may also not be eligible for thrombolyticsA medication that breaks up blood clots..[1-3]

Thrombolysis is widely available and easy to administer. However, another potential problem is that it does not always fully restore bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. flow. In around 10-20 per cent of people given thrombolysisBreaking up a blood clot by administering medications called thrombolytics., the affected bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. vessel may become blocked again later on. In addition, 1-2 per cent of people treated with thrombolyticsA medication that breaks up blood clots. will have a stroke.[5,6]

Angioplasty

During angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility., a very thin flexible tube called a catheterA tube used either to drain fluid from the body or to introduce fluid into the body. is passed through an arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood., for example, in the groin or arm, and threaded up through to the arteries of the heart - the coronaryRelating to the arteries supplying the heart itself. arteries. This is first used to examine the arteries, a test called angiographyX-ray imaging of the blood vessels following the injection of a dye to improve visibility.. Then a small fine wire is used to cross any blocked arteries and a balloon is inflated within the blocked arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. to open a stentA tube placed inside a tubular structure in the body, to keep it patent, that is, open., a small device that is left in place to keep the walls of the arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. open. This widens the arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. so that bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. flow can be restored.

Many doctors believe that angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility. is the best method of reperfusionRestoration of blood flow through a previously blocked vessel. therapy if it is available in time - in practical terms, this means that a nearby catheterA tube used either to drain fluid from the body or to introduce fluid into the body. laboratory needs to be open at the time that the person needs treatment.

Angioplasty has better outcomes than thrombolysisBreaking up a blood clot by administering medications called thrombolytics. and there is a lower risk of stroke or recurrent heart attackThe death of a section of heart muscle caused by an interruption in its blood supply. Also called a myocardial infarction.,[1,2,6] but because it is not always available, thrombolysisBreaking up a blood clot by administering medications called thrombolytics. is often the first-line treatment for a heart attackThe death of a section of heart muscle caused by an interruption in its blood supply. Also called a myocardial infarction..[1,2]

However, even if thrombolysisBreaking up a blood clot by administering medications called thrombolytics. is used as the initial treatment, people still have an option of an angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility. at a later stage if reperfusionRestoration of blood flow through a previously blocked vessel. by thrombolysisBreaking up a blood clot by administering medications called thrombolytics. has been unsuccessful.[7] This means that people who have thrombolysisBreaking up a blood clot by administering medications called thrombolytics. as their immediate treatment are often transferred to a facility where angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility. is available, in case this is needed at a later time.[5]

Angiography also allows for better identification of any complications of a heart attackThe death of a section of heart muscle caused by an interruption in its blood supply. Also called a myocardial infarction..[5] In addition, advances in angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility. have improved outcomes even further. One example is drug-eluting stents, which slowly release medication within the arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. to prevent the formation of scar tissueA type of connective tissue that forms after a wound heals., although the long-term outlook with this type of stentA tube placed inside a tubular structure in the body, to keep it patent, that is, open. is still under review.

Patients may gain better relief of ongoing symptoms of coronaryRelating to the arteries supplying the heart itself. arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. disease, such as anginaA central chest pain caused by insufficient oxygen supply to the heart., with an operation known as coronary artery bypass.[8,9]

References: 
  1. Diagnosis and management of ST elevation myocardial infarctionDeath of an area of heart muscle due to poor blood supply.: a review of the recent literature and practice guidelines.  Hahn SA and Chandler C. The Mount Sinai Journal of Medicine 2006;73:469-81.
  2. Unstable anginaA central chest pain caused by insufficient oxygen supply to the heart. and non-ST-segment myocardial infarctionDeath of an area of heart muscle due to poor blood supply.: an evidence-based approach to management. Kou V and Nassisi D. The Mount Sinai Journal of Medicine 2006;73(1):449-68.
  3. Boon NA, Colledge NR and Walker BR. Davidson's Principles and Practice of Medicine. Churchill Livingstone Elsevier. 2006; 20th edition.
  4. Immediate angioplastyThe mechanical widening or clearing of a narrowed or obstructed blood vessel, performed during angiography, which is used to help with visibility. after thrombolysisBreaking up a blood clot by administering medications called thrombolytics.: a systematic review. Cantor WJ, Brunet F, Ziegler CP et al. CMAJ 2005;173(12):1473-81.
  5. Narrative review: reperfusionRestoration of blood flow through a previously blocked vessel. strategies for ST-segment elevation myocardial infarctionDeath of an area of heart muscle due to poor blood supply.. Ting HH, Yang EH and Rihal CS. Ann Intern Med 2006;145:610-7.
  6. Primary percutaneous coronary interventionAngioplasty: the mechanical widening or clearing of a narrowed or obstructed blood vessel. for acuteHas a sudden onset. MIMyocardial infarction. Death of a segment of heart muscle, which follows interruption of its blood supply.: improving access and outcomes. Karha J, Hook MA and Brener SJ. Cleveland Clinic Journal of Medicine 2005;72:559-76.
  7. Recent advances in primary percutaneous intervention for acuteHas a sudden onset. myocardial infarctionDeath of an area of heart muscle due to poor blood supply.. Smith EJ, Mathur A and Rothman MT. Heart 2005;91:1533-6.
  8. Status of percutaneous coronary interventionAngioplasty: the mechanical widening or clearing of a narrowed or obstructed blood vessel. and coronaryRelating to the arteries supplying the heart itself. arteryA blood vessel that carries blood away from the heart. Apart from the pulmonary artery and umbilical artery, all arteries carry oxygenated blood. bypass. Barner HB. European Journal of Cardio-thoracic Surgery 2006;30:419-24.
  9. Drug-eluting stentA tube placed inside a tubular structure in the body, to keep it patent, that is, open.: a review and update. Htay T and Liu MW. Vascular Health and Risk Management 2005;1:263-76.