Why don't stents prevent heart attack?

No study has ever documented that stents prevent future heart attack. But, in day-to-day practice, stents are frequently implanted for just this reason.

A little clarification. Stents do prevent heart attack--if the heart attack is already underway, either as an "acute myocardial infarction" or "unstable angina."

In other words, a plaque in a coronary artery can rupture just like a little volcano. Rather than spewing lava, the underlying plaque contents--fibrous tissue, inflammatory cells, cholesterol crystals, fatty material, debris--are exposed to flowing blood and trigger spasm of the artery and blood clot formation. A ruptured plaque is typically found in people who go to the emergency room with severe chest pain or have difficulty breathing.

A heart catheterization is performed, a severe (e.g., 90-100%--completely closed) is found. A stent in this situation is of clear-cut benefit.

What is not clearly beneficial is someone with no symptoms, symptoms only with physical activity that has been present for at least several months, or someone with a high heart scan score and no symptoms. In these circumstances, stent implantation does not reduce risk for future heart attack.


Take a look at this angiogram of a right coronary artery. You can seen plaque all along the artery (represented by areas that appear pinched off. There are at least 4 visible.)

Putting one 15 millimeter stent in the artery will only affect the area of artery stented. (Stents vary in length, but typically are 12-18 millimeters in length.) The right coronary artery is about 10 times or more this length. There are also two other arteries of similar length. A stent at one location will do nothing to affect the potential for rupture in any of the other plaque-laden areas.

Say a stent is implanted in the "worst" blockage in this right coronary artery, the plaque located at around 9 o'clock. What about all the other plaques? They can still rupture.

Why not put in many stents, say, 4 or 5, and stent all the visible plaques?

Two reasons: 1) Plaque you can't even see on an angiogram can still rupture, and 2) it is very costly (easily $30,000 at the very least), 3) incurs greater procedural risk, and 4) messes up the artery for future procedures, since a steel-lined artery that develops more disease in future will be more difficult to re-implant stents, bypass, or perform other procedural manipulations.

The point: Putting in stents does not reduce potential for plaque rupture in the entire artery.

What can prevent plaque rupture? That's the whole point of following an effective prevention program: prevent plaque rupture.

(Of course, this discussion cannot encompass the wide variety of potential situations that may cause your doctor to individualize your approach. Nonetheless, when advised to have an elective heart procedure, a healthy dose of skepticism and is clearly a good practice.)

Top image courtesy National Heart, Lung, and Blood Institute.

Comments (11) -

  • Get Primal

    2/13/2009 2:17:00 AM |

    Great post, it's too bad more effort and resources don't go into the initial prevention.  I'm a sales rep that works in the cath lab (peripheral vascular and vessel closure products), love the blog!

  • vin

    2/13/2009 9:57:00 AM |

    I don't ever remember my doctor ever talking about the chance of a plaque rupturing at one of the almost blocked points. His reason for putting in a stent at the worst point is to protect the patient from a total blockage at that point. So argument for a stent is to give the patient a few more years prior to a follow up bypass surgery.

  • Kiwi

    2/13/2009 10:07:00 AM |

    Hi Dr. Davis,
    What other procedures are likely in the future regarding blocked arteries? I understand dissolvable stents are being trialed. Are we likely to see any other developments?

  • Lynn

    2/17/2009 3:45:00 AM |

    I am an otherwise very active and healthy 57 year old female who has already had 4 stents placed in my RCA following 2 separate MI's.  Each event was 5 years apart. Needless to say I feel like a time bomb.  I have visited several cardiologists and have finally found one who is looking at my CAD from a more aggressive standpoint and that is prevention. Following a recent cath procedure I have slightly 40% at the site of the last stenting.  This will no doubt need to be addressed but when?  I would prefer before I have another event!  However...I've yet to hear about what supplements (Vitamin D3 ) that could perhaps slow the progression of my disease of perhaps elminate/reduce the placque already there.
    Any suggestions?  If indeed you could answer, I'd prefer an email. Thanks for educating us!

  • Anonymous

    2/20/2009 2:32:00 AM |

    I am 45 year old (from India) have
    VERY strong history ( Father-3 Mi's)
    of Coronary disease and diabetes.
      My annual checkup showed
    TC- 282
    TG- 442
    LDL- 173
    HDL- 39
    Had slightly elevated #s before(10yr)
    My Internist sent me for a heart scan and MY SCORE is ZERO / ZERO /
    and ZERO, ANY comments Dr.

  • selahV

    2/27/2009 9:38:00 PM |

    I am scheduled for an angiogram next Friday.  My stress test showed what appears to be a blockage in a front artery of my heart, the doctor says.  What he didn't say was what would happen if I have a blockage when they get inside.  Should I be asking more questions?  what should I ask?

  • Anonymous

    6/29/2009 9:08:16 AM |

    I am a 47 year male from India and have undergone angiogram recently and the report shows there is 80% block in the main artery. Advice and guide whether  stent is adviceable if the patient is diabetic.

  • buy jeans

    11/3/2010 9:22:00 PM |

    (Of course, this discussion cannot encompass the wide variety of potential situations that may cause your doctor to individualize your approach. Nonetheless, when advised to have an elective heart procedure, a healthy dose of skepticism and is clearly a good practice.)

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    1/26/2011 5:42:45 AM |

    Medications are the best way to prevent this from happening.there is no reason to think stents would prevent heart attack. "What happens when you put a stent in is you're attacking one narrowing in the artery, but it's not the narrowing that's going to cause the next heart attack,"

  • how to

    2/3/2011 7:11:50 PM |

    I recently came across this article and have been reading along. I thought I would leave my first comment. I don't know what to say except that I have enjoyed reading. Really a nice post here!


    3/5/2011 6:01:21 AM |

    I am scheduled for an angiogram on Friday. My stress test showed what appears to be a blockage in an artery in front of my heart, says doctor. He did not say was what would happen if I have a crash when they are inside. Should I ask more questions? What should I do?

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