November 17th, 2010
05:10 PM ET

What causes new blockages to form so quickly?

Every weekday, a CNNHealth expert doctor answers a viewer question. On Wednesday, it's Dr. Otis Brawley, a chief medical officer for the American Cancer Society.

Question asked by Angi Garton of Chariton, Iowa:

My mother had triple bypass surgery one year ago. She was having chest pain again and hospitalized. There are more blockages, one right below a bypass and 70 percent blockage through a bypass. Also one bypass has failed. Her cholesterol and blood pressure are in good ranges and under control. What would have caused the new blockages so quickly from a year ago?

Expert answer

Unfortunately, it is rather common for a patient to have blockages in the coronary arteries and in the bypass after a coronary artery bypass graft (or CABG).

The heart muscle is threatened when one or more of the arteries carrying oxygenated blood through it is partially or completely blocked. It can be blocked by a cholesterol plaque, a blood clot or a combination of the two. Heart muscle beyond the blockage cannot get enough oxygenated blood. This can cause the chest pain called angina. Prolonged decreased blood flow can cause death of heart muscle which is referred to as a myocardial infarction or a heart attack.

Minor blockages of the coronary artery are treated with medications that dilate the arteries and lower blood pressure which decreases the workload and oxygen requirement of the heart. More severe blockages have to be treated with an angioplasty, angioplasty and placement of a stent, or with a coronary artery bypass graft. Angioplasty is when a catheter is passed, usually from the femoral artery in the groin up to the heart and a balloon-like device is placed in the coronary artery to the level of the partial occlusion and inflated to open the blockage. A stent, a tiny tube, can be left behind to keep the artery open. A coronary artery bypass is an open-chest surgery. A surgeon takes a piece or graft of artery or vein from elsewhere in the body. The graft is then stitched into the coronary artery so that blood can detour around the blockage. Think of a CABG as creating a detour or alternative route for blood flow around a partial or completely blocked artery. All of these treatments are designed to allow muscle beyond the blockage to get oxygenated blood.

When CABG is done the surgeon may choose to use the saphenous vein from the leg or the internal mammary artery (IMA) from the chest and armpit for the bypass graft. The condition of the patient is factored into the decision to use one or the other. In surveys more than 80 percent of CABGs are done with the right or left internal mammary artery. In the first five years after surgery, the internal mammary artery grafts are less likely to occlude compared with the saphenous vein.

In studies of several thousand people getting CABG using the saphenous vein, 10 percent have graft occlusion within the first few weeks to a year after surgery. It occurs in 35 to 40 percent by five years after the operation and 40 to 50 percent at 10 years. Factors that predispose to saphenous vein graft disease, include the size of the vein graft. Smaller diameter veins being at higher risk. Remember women are likely to have smaller vein grafts and are thus at higher risk than men. Other risk factors include length of the vein grafted (longer being at higher risk), smoking history before and after surgery, hypertension in the weeks after surgery, and lipid abnormalities in the weeks after surgery. Interestingly diabetes and poor blood sugar control appear to have little role as a risk factor for early occlusion of the grafts but is a risk factor later.

One percent of left internal mammary artery grafts and six percent of right IMA graphs develop blockages within three months of surgery. Over the long term, 10 to 15 percent of internal mammary grafts develop occlusion. Factors that increase risk of IMA occlusion include the area of the heart that needs to be grafted and the severity of the blockages being bypassed. A more severe blockage in a coronary artery correlates with decreased chances of a blockage in the graph presumably because of higher blood flow in the graph.

IMA grafts are generally preferred because they have a higher long-term patency rate. Sometimes the internal mammary artery cannot be used, necessitating the use of the saphenous vein. In select cases, some surgeons are now using the radial artery from the forearm or the the right gastroepiploic artery (from the stomach).

Studies show that one can decrease risk of occlusion of both the veinous and arterial grafts and the coronary arteries by aggressively reducing LDL-cholesterol with statin therapy and possibly through blood pressure control to low normal levels. Patients also generally benefit from low-dose aspirin therapy, some doctors prefer the antiplatelet agent clopidogrel instead of aspirin. Avoidance of smoking, controlling the serum glucose in diabetes is also important. Unfortunately these reduce but do not eliminate risk of occlusion.

I will discuss angioplasty and cardiac stents next week.

soundoff (1,116 Responses)
  1. Aika Private Server


    May 15, 2021 at 22:29 | Report abuse | Reply
  2. FmrfEncox

    cialis online doctor http://cialisee.com/ – cialis us pharmacy discount cialis

    May 15, 2021 at 22:42 | Report abuse | Reply
  3. aika online private server


    May 16, 2021 at 01:10 | Report abuse | Reply
  4. Aika Online

    Excellent article. I absolutely love this site. Stick with it!


    May 16, 2021 at 01:56 | Report abuse | Reply
  5. brimonidine

    combigan uk combigan bottle sizecombigan

    May 16, 2021 at 04:53 | Report abuse | Reply
  6. Aika Skill Simulator

    I absolutely love your site.. Pleasant colors & theme. Did you develop this site yourself? Please reply back as I’m hoping to create my very own site and want to find out where you got this from or what the theme is named. Many thanks!


    May 16, 2021 at 04:54 | Report abuse | Reply

    Wow, fantastic weblog format! How lengthy have you
    ever been running a blog for? you made blogging glance easy.
    The whole glance of your website is fantastic, let alone the content!

    May 16, 2021 at 10:29 | Report abuse | Reply
  8. Zopiclone

    Just wish to say your article is as astonishing.
    The clearness on your put up is just nice and
    i could think you're a professional on this subject.

    Fine along with your permission let me to clutch your
    feed to stay up to date with forthcoming post. Thanks 1,000,000 and please continue the gratifying

    May 16, 2021 at 11:09 | Report abuse | Reply
  9. camera shop orange county

    After going over a handful of the blog posts on your website, I really appreciate your technique of writing a blog. I saved as a favorite it to my bookmark website list and will be checking back in the near future. Please visit my website too and tell me how you feel.


    May 16, 2021 at 12:14 | Report abuse | Reply
  10. modafinil dosage

    modafinil dosage buy modalert

    May 16, 2021 at 12:41 | Report abuse | Reply
  11. Sprinter Van Inside Computer Repair Shop


    May 16, 2021 at 13:17 | Report abuse | Reply
  12. 2006 Mercades Sprinter 2500 Turbo Actuator Repair


    May 16, 2021 at 15:49 | Report abuse | Reply
  13. Approved Sprinter Repair Shops Near Me


    May 16, 2021 at 16:40 | Report abuse | Reply
  14. Frieghtliner Sprinter Abs Module Repair


    May 16, 2021 at 17:07 | Report abuse | Reply
  15. Sprinter Van Inside Computer Repair Shop

    Aw, this was an extremely good post. Finding the time and actual effort to make a top notch article… but what can I say… I put things off a lot and don't manage to get anything done.


    May 16, 2021 at 19:35 | Report abuse | Reply
  16. Los Angeles Sprinter Repair

    An interesting discussion is worth comment. I do believe that you should write more about this subject, it might not be a taboo matter but generally people don't talk about these issues. To the next! Kind regards!!


    May 16, 2021 at 21:59 | Report abuse | Reply
  17. Sprinter Van Repair Shops


    May 16, 2021 at 22:06 | Report abuse | Reply
  18. LebnEncox

    mexican pharmacy weight loss https://xlnpharmacy.com/ canada prescription plus pharmacy

    May 16, 2021 at 22:33 | Report abuse | Reply
  19. Diesel Sprinter Repair Near Me

    Excellent web site you have here.. It’s hard to find excellent writing like yours nowadays. I truly appreciate individuals like you! Take care!!


    May 17, 2021 at 00:07 | Report abuse | Reply
  20. Maserati Birdcage 75Th


    May 17, 2021 at 00:54 | Report abuse | Reply
  21. Sprinter Repair Costs


    May 17, 2021 at 02:13 | Report abuse | Reply
  22. Mercedes Benz Sprinter Repair Shop

    Good day! I simply want to give you a huge thumbs up for the great info you've got here on this post. I am returning to your website for more soon.


    May 17, 2021 at 06:51 | Report abuse | Reply
  23. 2006 Sprinter Fuel Pump Repair

    This excellent website really has all of the information and facts I wanted about this subject and didn’t know who to ask.


    May 17, 2021 at 07:30 | Report abuse | Reply
  24. http://lendingworkbench.Com/__media__/js/netsoltrademark.php?D=cheapejuice.com

    Just desire to say your article is as surprising. The clearness for your put up
    is simply cool and i can think you're knowledgeable in this subject.
    Fine with your permission let me to grasp your feed to keep
    updated with impending post. Thanks one million and please carry on the enjoyable work.

    May 17, 2021 at 09:48 | Report abuse | Reply
  25. RV Blinds Orange County

    I really like looking through a post that can make people think. Also, thanks for permitting me to comment!


    May 17, 2021 at 13:29 | Report abuse | Reply
  26. Maserati Eva Notty


    May 17, 2021 at 13:41 | Report abuse | Reply
  27. AnooEncox

    viagra and the eye https://llviagra.com/ – venta de pastillas viagra viagra generico comprar brasil

    May 17, 2021 at 15:39 | Report abuse | Reply
  28. best rv service near me

    This is a topic that is close to my heart... Thank you! Where are your contact details though?


    May 17, 2021 at 15:55 | Report abuse | Reply
  29. rv repair santa fe


    May 17, 2021 at 16:51 | Report abuse | Reply
  30. RV Fabrication Near Me

    You should be a part of a contest for one of the greatest sites on the internet. I am going to recommend this blog!


    May 17, 2021 at 17:14 | Report abuse | Reply
  31. Automotive Courses

    Awesome article.

    May 17, 2021 at 17:21 | Report abuse | Reply
  32. JebgEncox

    Fertomid http://pharmacylo.com/ best drugstore foundation

    May 18, 2021 at 00:08 | Report abuse | Reply
  33. product roadmap

    I am truly grateful to the holder of this web page who has
    shared this fantastic paragraph at at this place.

    May 18, 2021 at 03:29 | Report abuse | Reply
  34. הגשת תמלול הקלטה

    I simply could not leave your website before suggesting that I actually enjoyed the usual
    information a person supply to your visitors? Is going to be back
    frequently to investigate cross-check new posts

    May 18, 2021 at 05:20 | Report abuse | Reply
  35. viral

    I lokved as much as you'll receive carried out right here.
    The skerch is tasteful, your authored material stylish.

    nonetheless, you command get got an impatience over
    that you wish be delivering the following. unwell
    unquestionably come more formerly again since exactly the sam nearly very often inside case you shield
    this hike.

    May 18, 2021 at 05:42 | Report abuse | Reply
  36. more information

    There's definately a great deal to find out about this topic.
    I love all of the points you made.

    May 18, 2021 at 07:16 | Report abuse | Reply
  37. things to do in azusa ca


    May 18, 2021 at 11:03 | Report abuse | Reply
  38. JebgEncox

    italian pharmacy online https://pharmacylo.com/ canada pharmacies without script

    May 18, 2021 at 18:50 | Report abuse | Reply
  39. heating and air conditioning store near me

    I was able to find good information from your content.


    May 18, 2021 at 20:18 | Report abuse | Reply
  40. poker idn

    What's up to all, how is all, I think every one is getting more from this site, and your views are
    fastidious designed for new visitors.

    May 18, 2021 at 20:55 | Report abuse | Reply
  41. New Forklift Cylinders California


    May 18, 2021 at 23:10 | Report abuse | Reply
  42. Commercial Roof Installation


    May 19, 2021 at 02:19 | Report abuse | Reply
  43. Social Media Marketing Orange County


    May 19, 2021 at 03:03 | Report abuse | Reply

    When I initially left a comment I seem to have clicked on the -Notify me when new comments are added- checkbox and from now on every time a comment is added I get 4 emails with the
    same comment. Perhaps there is a way you are able to remove me
    from that service? Thanks a lot!

    May 19, 2021 at 03:41 | Report abuse | Reply
  45. webpage

    Thamks for every otgher magnificent post. The place else may just anybody
    get that kind of info in such ann ieal method of writing?
    I have a presentation subsequent week, and I am at the look for such information.

    May 19, 2021 at 03:42 | Report abuse | Reply
  46. Best Roofing Companies Near Me


    May 19, 2021 at 06:56 | Report abuse | Reply
  47. prescribed energy pills

    Everyone loves it when folks get together and share thoughts. Great blog, keep it up!


    May 19, 2021 at 08:11 | Report abuse | Reply
  48. scr888 xmod

    Just desire to say your article is as astonishing. The clarity in your post is just
    nice and i can assume you're an expert on this subject.
    Fine with your permission let me to grab your feed to keep up to date with forthcoming post.
    Thanks a million and please continue the rewarding work.

    May 19, 2021 at 10:50 | Report abuse | Reply
  49. scr888 bet

    No matter if some one searches for his required thing, thus he/she desires to be available that in detail, so that thing is maintained over

    May 19, 2021 at 10:51 | Report abuse | Reply
  50. scr888 apk download android 2017

    It's in point of fact a great and useful piece of info.
    I am satisfied that you shared this helpful information with us.

    Please keep us informed like this. Thank you for

    May 19, 2021 at 10:52 | Report abuse | Reply
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Post a comment


CNN welcomes a lively and courteous discussion as long as you follow the Rules of Conduct set forth in our Terms of Service. Comments are not pre-screened before they post. You agree that anything you post may be used, along with your name and profile picture, in accordance with our Privacy Policy and the license you have granted pursuant to our Terms of Service.

About this blog

Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.