Heart Attack Signs and Symptoms

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Heart Attack 4

How Does "Clot Buster" Treatment Compare With Emergency Angioplasty and Coronary Stenting?

This is an excellent question for which there is no easy answer. Let’s first look at intravenous thrombolytic (clot buster) treatment which became one of the more important advances in the treatment of heart attacks since its introduction. It offers the following advantages:

In comparison with standard medical treatment, thrombolytic therapy reduces the 35-day mortality (death rate) by 21%. This corresponds to an overall reduction of 21 deaths per 1000 patients treated in this manner.
Time is of essence with the use of thrombolytic treatment. Higher benefits are achieved when it is given within 6 hours of the onset of heart attack symptoms. Best results are observed within two to three hours but continue to be beneficial even if started within 12 hours.
35 per 1000 lives are saved when it is used within the first hour of symptoms. This drops to 16 lives saved per thousand if treatment is delayed for 7 to 12 hours.
Thrombolytic therapy benefits the patient regardless of age, sex or presence of risk factors for coronary artery disease.
Disadvantages include a small risk of a stroke (2%) with a little over half of these (1.1%) due to bleeding. To place this in proper perspective, the risk of a stroke due to thrombolytic treatment is far outweighed by the number of lives that are saved.

Reference: ACC/AHA Guidelines for Patients with Acute Myocardial Infarction: Executive Summary, Circulation, Nov 1, 1996

Next, let us examine the advantages of angioplasty performed as a primary procedure in the treatment of a heart attack. According to the recommendations of the American College of Cardiology and the American Heart Association Guidelines (above), primary angioplasty may be performed as an alternative to thrombolytic therapy in the following circumstances:

It can be accomplished in a timely manner by skilled and experienced staff.
There is prompt access to coronary bypass graft surgery.

Advantages of Primary Angioplasty

About half of patients treated with thrombolytic therapy continue to have a significant blockage (since the treatment breaks up blood clots but does nothing for the underlying blockage) and reduced blood flow in the affected artery. In comparison, blood flow is brisk and mild or no blockage is left behind in over 90% of cases treated with primary angioplasty with or without stenting.
The mortality or death rate with primary angioplasty is 60% lower than that achieved with thrombolytic therapy (4.4% compared to 6.5%).(Reference: JAMA 278:2093, 1997)
The risk of stroke is reduced by more than 50%, compared to thrombolytic therapy.
The probability of having an open artery after 6 months with thrombolytic therapy alone is 59%. The odds improve to 87-91% at 3-6 months with primary angioplasty (References: NEJM: 328, 1993 and Circulation 90:156, 1994).
In studies where patients were randomized to thrombolytic therapy versus primary angioplasty, those treated with thrombolytic therapy required subsequent PTCA or bypass surgery in 30% of cases. In contrast, only 5% of patients treated with primary angioplasty required a subsequent procedure or surgery during the 3-6 month follow-up (Reference: Circulation 10 [Suppl A] 12A, 1998).
With Primary Stenting in heart attacks, the success rate of the procedure is increased to greater than 95% with less than 1% (0.8%) mortality (death rate) within the hospitalization period (Reference: Cathet Cardiovasc Diag 44, 118, 1998).
The restenosis rate (chance of blockage returning at same site) is around 25% at 7 months in cases of primary stenting for heart attacks (Reference: J Am Coll Cardiol 31, 23, 1998).

If Primary Angioplasty and Stenting Are So Good, Why Aren’t They Used in Every Patient With a Heart Attack?

Since only 18% of hospitals are equipped to perform emergency angioplasty and stenting in patients with heart attacks, this form of treatment is not available in the remaining 82% of hospitals that admit patients with chest pain. Importantly, time is of essence in getting rid of obstructing blood clots and salvaging heart muscle. In most cases, the patient is much better receiving a "clot buster" medication in the emergency room if access to a hospital with a cardiac cath lab is not readily available.