Mortality after Weight Loss surgery 

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Regarding Surgical Mortality Statistics

By G. Wesley Clark, MD, bariatric surgeon, San Diego, CA
(co. 2003, reprinted by permission of the author)

I am a weight-loss surgeon, with an experience of over 2000 operations, over the last 17 years. I was an originator of the Laparoscopic Gastric Bypass, Roux en-Y. My personal mortality is about 1:1000 for the laparoscopic procedure, somewhat higher for the open operation (not because the operation is more dangerous that way, but because more high-risk patients must be done by that method). I have the advantage of operating in a hospital where the entire team has experience, and where we have special equipment for the obese patient.

Mortality from surgery is usually determined by taking mortality from all causes within 30 days of the operation. For example, if one had a minor and safe operation, and was run down by a beer truck 27 days later, it would be considered a surgical mortality, even though it is apparently not related to the operation. This is a very stringent method, but eliminates any judgments about whether or not the death was caused by the operation. This method may overstate mortality from a safer operation: if one gets better fast, and is more active, there is a slightly greater chance of death from an unrelated cause, due to activity. On the other hand, a patient with severe surgical complications might survive for several months before expiring, and not be counted. That’s the problem with statistics.

Low mortality rates for 3 days after surgery are very misleading. Even the patient with a severe sepsis, or a brain-death, will usually survive for that long, and not be counted against the surgery.

The most commonly cited mortality rate for bariatric surgical operations, across the United States, is 0.5%. That looks pretty good, till you do the math and realize that means about 1 out of 200 patients will experience a fatal result.

This increased risk arises from numerous factors, and is not just for bariatric surgery, but any surgery performed on a very obese patient. I call this the “fat penalty”. The increased mortality arises from numerous factors:

  • Anesthetic Risk
    Most anesthesiologists shudder to see an obese person on their table. They know it may be very difficult to insert the anesthetic tube into the airway, and very dangerous if it comes out too soon. Ventilator pressures must be set a lot higher, because of the weight of the chest. Drugs and anesthetic gases may be absorbed by the fat, requiring much higher doses to take effect, and much longer to be eliminated when they are no longer needed. Obese patients don’t breath well to begin with (they get out-of-breath from simple daily activities), and may have much more difficulty after surgery. Moving an unconscious patient is always difficult and tricky, but can be much more so when the patient weighs 400 pounds. Our hospital has special equipment to assist with this and make it safer. You want a highly skilled anesthesiologist, experienced with treating obese patients.
  • Surgical “Degree of Difficulty”
    Obese persons are much more difficult for the surgeon to operate upon. Normally, the abdominal organs are all fitted together, with no space between them. In order for the surgeon to see to operate, they must be separated and held apart in some way – this is called “surgical exposure”. Exposure can be very challenging to achieve and maintain, when there are large amounts of fat constantly slipping and sliding about, and getting in the way. Fat on the surface of the organs may make it harder to place sutures accurately.
    The abdominal wall may be 4 – 5 inches thick in the obese patient. That means that ordinary surgical instruments won’t reach, and we have to use extra-long instruments, which are much harder to learn to manipulate precisely.
    That’s why you want a highly skilled and experienced Bariatric Surgeon.
  • Surgical Complications
    Obese persons have a much higher rate of complications. Obesity is a risk factor for Pulmonary Embolism, which is often fatal. Post-operative Pneumonia is also more likely in the obese. Wound infections are considered more likely, and because of the size and depth of the wound, can be very challenging to heal. Complications can be much harder to diagnose and manage in the obese patient. For example, X-Rays do not penetrate as well, and the pictures are less clear. Very large patients will not fit in some equipment, such as the CT scanner.

    Many surgeons with limited experience in surgery of the obese patient will decline to operate on an obese person, even when the indications are there, because of their perception of the increased risk, and the altered risk/benefit ratio. Many transplant surgeons will refuse to transplant organs in an obese patient (not overtly, they just never seem to find the right organ match). Many orthopedic surgeons decline to do joint replacements, especially knees, in obese persons.

    All surgery carries risks, and all surgeons have patients who experience complications, even when surgery is done "perfectly". When a complication occurs, the most important factor in determining mortality, I believe, is the experience, knowledge and skill of the treatment team.

What about the Benefits?

One should only seek Bariatric Surgery to protect or to restore health. It is not a cosmetic operation, although it has some pleasant side-benefits. To decide whether Bariatric Surgery is right for you, the risks and the benefits should be understood, and weighed one against the other. We do that all the time in life, usually without realizing it. (I ride a motorcycle, even though I know it’s risky, because I get such a high from it. I don’t eat sushi, because I don’t like it that much, and raw fish can have bad things in it).

The benefits of bariatric surgery, beyond a lighter weight and smaller dress size, have been relatively poorly demonstrated in the surgical literature. We found (and published) that in our first 500 Laparoscopic Gastric Bypasses, there were 1572 major co-morbidities (health problems related to obesity) --over 3 per patient, on the average. Following surgery, one year later, these were reduced by 96%. Ninety-six percent of the obesity-related health problems were gone.

Of 80 diabetics, only one continued to require any medication. Risk factors for cardiac disease were dramatically reduced. Arthritic symptoms almost disappeared, and even when some joint pain remained, it was much lessened.

Dr. Kenneth McDonald has published a study of diabetics who undergo bariatric surgery, and showed a 75% reduction in mortality after surgery (even including a slightly higher than average surgical mortality).

That's the kind of results that justifies the risk of the operation -- my wife had a Laparoscopic Gastric Bypass 3 years ago, on my recommendation, and I'd be on the table next week myself, if I met the basic weight criteria, or if I developed Diabetes.

I started out years ago as a General Surgeon, taking out gallbladders, removing breasts, cutting out cancers. Nothing compares to the thrill I get when my patients return to me a year later, and want to hug me (no woman ever hugged me for taking her breast off). They've changed into beautiful butterflies, excited with their new lives, able to do things they never dared to dream about before. I became a physician, because I dreamt of healing people. I found my way to heal, and I love it.

G. Wesley Clark, MD
San Diego