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 (1,258 Responses)
  1. best gifts for baby

    An impressive share! I've just forwarded this onto a friend who had been doing a little homework on this. And he in fact bought me breakfast due to the fact that I discovered it for him... lol. So let me reword this.... Thanks for the meal!! But yeah, thanks for spending some time to discuss this issue here on your site.


    May 19, 2021 at 11:53 | Report abuse | Reply
  2. Sprinter Van Seat Fabric Repair


    May 19, 2021 at 14:19 | Report abuse | Reply
  3. AnooEncox

    what milligrams does viagra come in https://llviagra.com/ a que edad usar viagra

    May 19, 2021 at 14:42 | Report abuse | Reply
  4. trailer supplies orange county

    Very good info. Lucky me I recently found your blog by chance (stumbleupon). I have saved as a favorite for later!


    May 19, 2021 at 15:52 | Report abuse | Reply
  5. Internet Marketing Near Me


    May 19, 2021 at 17:29 | Report abuse | Reply
  6. BbshMile

    viagra for womens where to buy http://loxviagra.com/ liquid viagra

    May 19, 2021 at 17:49 | Report abuse | Reply
  7. RV Fabrication California


    May 19, 2021 at 20:27 | Report abuse | Reply
  8. Digital Marketing Specialists


    May 20, 2021 at 02:13 | Report abuse | Reply
  9. Google Marketing Company


    May 20, 2021 at 02:30 | Report abuse | Reply
  10. LebnEncox

    Doxycycline Moduretic canadadrugsonline

    May 20, 2021 at 02:57 | Report abuse | Reply
  11. Content Marketing Services


    May 20, 2021 at 03:08 | Report abuse | Reply
  12. Local Marketing Companies Near Me

    I like it when people come together and share opinions. Great site, continue the good work!


    May 20, 2021 at 03:31 | Report abuse | Reply
  13. SEO Marketing Consultants

    I like it when folks come together and share ideas. Great blog, continue the good work!


    May 20, 2021 at 04:23 | Report abuse | Reply
  14. cyclosporine

    cyclomune 0.1% eye drops cyclosporine 100 mg

    May 20, 2021 at 05:35 | Report abuse | Reply
  15. Internet Marketing Consultants


    May 20, 2021 at 05:57 | Report abuse | Reply
  16. Local Marketing Companies


    May 20, 2021 at 07:20 | Report abuse | Reply
  17. Digital Marketing Business

    I need to to thank you for this great read!! I certainly loved every bit of it. I have you bookmarked to check out new things you post…


    May 20, 2021 at 07:37 | Report abuse | Reply
  18. Digital Marketing Company

    You should take part in a contest for one of the greatest blogs on the net. I most certainly will recommend this web site!


    May 20, 2021 at 08:22 | Report abuse | Reply
  19. Local Marketing Companies Near Me


    May 20, 2021 at 11:05 | Report abuse | Reply
  20. fiberglass repair shops

    I truly love your blog.. Great colors & theme. Did you develop this amazing site yourself? Please reply back as I’m planning to create my own blog and would love to learn where you got this from or just what the theme is called. Appreciate it!


    May 20, 2021 at 13:53 | Report abuse | Reply
  21. RV Inspection Riverside

    Hi, I do believe this is a great blog. I stumbledupon it 😉 I'm going to return yet again since i have book marked it. Money and freedom is the best way to change, may you be rich and continue to help other people.


    May 20, 2021 at 13:54 | Report abuse | Reply
  22. RV Windshield California


    May 20, 2021 at 14:09 | Report abuse | Reply
  23. LbsoZisse

    cialis 10 mg price http://ucialisdas.com/ cialis viagra levitra samples

    May 20, 2021 at 14:33 | Report abuse | Reply
  24. RV Dent Repair California

    Spot on with this write-up, I really feel this web site needs far more attention. I’ll probably be back again to read more, thanks for the information!


    May 20, 2021 at 15:13 | Report abuse | Reply
  25. esurance repair shops


    May 20, 2021 at 15:59 | Report abuse | Reply
  26. slide out repair


    May 20, 2021 at 19:06 | Report abuse | Reply
  27. RV Seats Los Angeles

    Greetings! Very helpful advice in this particular post! It is the little changes that produce the most important changes. Many thanks for sharing!


    May 20, 2021 at 19:07 | Report abuse | Reply
  28. RV Flooring California


    May 20, 2021 at 19:51 | Report abuse | Reply
  29. RebfZisse

    buy some cialis http://rcialisgl.com/ cialis and viagra taken together

    May 20, 2021 at 22:25 | Report abuse | Reply
  30. RV Refrigerator California

    Nice post. I learn something new and challenging on sites I stumbleupon everyday. It will always be exciting to read through content from other writers and use something from other websites.


    May 20, 2021 at 22:48 | Report abuse | Reply
  31. Sprinter Blower Fan Repair Near Me

    A motivating discussion is definitely worth comment. I do believe that you need to write more about this subject, it may not be a taboo matter but generally folks don't talk about these topics. To the next! Best wishes!!


    May 21, 2021 at 00:33 | Report abuse | Reply
  32. rv orange county ca


    May 21, 2021 at 01:27 | Report abuse | Reply
  33. mobile rv repair los angeles


    May 21, 2021 at 03:46 | Report abuse | Reply
  34. motorhome service near me


    May 21, 2021 at 05:38 | Report abuse | Reply
  35. RebfZisse

    cialis no prescription https://rcialisgl.com/ – cialisgeneric where to get generic cialis without prescription

    May 21, 2021 at 06:22 | Report abuse | Reply
  36. flooring repair near me

    It’s difficult to find well-informed people on this subject, however, you seem like you know what you’re talking about! Thanks


    May 21, 2021 at 07:02 | Report abuse | Reply
  37. RV Alignment Orange County

    I was able to find good advice from your content.


    May 21, 2021 at 09:54 | Report abuse | Reply
  38. RV Collision Repair Riverside


    May 21, 2021 at 10:26 | Report abuse | Reply
  39. truck modification shop near me

    I was extremely pleased to discover this page. I wanted to thank you for your time for this particularly wonderful read!! I definitely loved every part of it and I have you saved as a favorite to check out new things in your blog.


    May 21, 2021 at 12:45 | Report abuse | Reply
  40. LbsoZisse

    indian cialis https://ucialisdas.com/ free samples cialis

    May 21, 2021 at 13:12 | Report abuse | Reply
  41. AnooEncox

    julio iglesias viagra https://llviagra.com/ no prescription viagra sale

    May 21, 2021 at 16:26 | Report abuse | Reply
  42. Digital Marketing Service

    Hi there! I just want to give you a huge thumbs up for your great information you have here on this post. I'll be coming back to your site for more soon.


    May 21, 2021 at 16:44 | Report abuse | Reply
  43. GtnbCrulk

    online pharmacy ezzz viagra http://jokviagra.com/ cialis or viagra

    May 21, 2021 at 17:18 | Report abuse | Reply
  44. SEO Marketing Specialist


    May 21, 2021 at 22:41 | Report abuse | Reply
  45. american leak detection orange county

    Hey there! I simply would like to offer you a huge thumbs up for the great info you've got here on this post. I am coming back to your web site for more soon.


    May 22, 2021 at 02:05 | Report abuse | Reply
  46. travel trailers orange county

    Pretty! This has been an incredibly wonderful article. Thanks for supplying this information.


    May 22, 2021 at 02:28 | Report abuse | Reply
  47. RV Dent Repair Orange County

    Excellent article. I'm going through many of these issues as well..


    May 22, 2021 at 08:14 | Report abuse | Reply
  48. RV Mechanics California

    Good web site you have got here.. It’s difficult to find high-quality writing like yours these days. I really appreciate individuals like you! Take care!!


    May 22, 2021 at 09:18 | Report abuse | Reply
  49. Internet Marketing Specialist

    I couldn’t refrain from commenting. Exceptionally well written!


    May 22, 2021 at 09:46 | Report abuse | Reply
  50. Video Marketing Companies Near Me


    May 22, 2021 at 12:01 | 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 24 25 26

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.

November 2010
  • An error has occurred, which probably means the feed is down. Try again later.