As you may or may not know, mortality in bariatric surgery occurs at a very acceptable 0.2-0.3% rate. Compare this to gall bladder or appendix surgery (0.3 to 0.4%).
This means that in this class of obese people, if we operate on a thousand, two will die. If you take these same thousand people and just let them carry on the same way (with medical treatment, etc.) HALF of them would be dead in 20 years! In fact, the five year mortality of these patients is high enough to justify bariatric surgery.
Even though this is pretty impressive stuff to demonstrate how life-saving and life-altering bariatric surgery can be, what happens to an individual case where the patient dies? For that family, the mortality rate is 100%! Can things be any worse for them? No.
Therefore, if we could try and reduce the mortality of surgery even further, why would we not do it?
If we could weed out the highest risk cases, it would be half the battle won. We could then simply try not to operate on this high-risk class of patients, UNLESS there is a clear and explicit understanding and acceptance that they have a significant chance of dying within a month of surgery.
So the highest risk is seen in these groups:
- Elderly
- Males
- High BMI
- Smokers, alcoholics
- History of pulmonary embolism/DVT
- Re-do bariatric surgery
Recently, a paper showed statistics that suggest that bariatric surgery in elderly men does NOT offer the benefits other patients derive from it.
Why do patients die?
The most common reason is Pulmonary Embolism. Obese patients are prone to get blood clots in the leg and pelvic veins (Deep Vein Thrombosis) that can fragment and go into the blood stream before they get trapped in the lungs and obstruct the right heart’s main artery (pulmonary artery). To prevent this, we employ three common methods in hospital:
- Chemical prophylaxis: injections of heparin or low molecular wight heparin (LMWH) daily under the skin till the patient is mobile and ambulant.
- Mechanical prophylaxis: Sequential Compression Device (SCD) is used universally. The legs get compressed serially from below up by a machine that pumps air under pressure into stockings worn on the lower limbs.
- Mobilisation: pre- and post-op movement out of bed is strongly encouraged. In special situations (paralysis, orthopedic handicap) the mobilisation may be done by a special physiotherapist.
Statistically, DVT/PE occurs even at home two weeks after the patient gets discharged. This clearly suggests that there is a chance of PE two weeks after stopping DVT prophylaxis. As this chance is maximal in the first month or so, it may be appropriate to continue LMWH injections for 30-45 days at home, especially when the patient falls into the high-risk category.
At BMI, we have now adopted this policy clearly for the higher risk patients.
In patients with a history of deep vein thrombosis or PE, further episodes of PE may be avoided by placing an umbrella in the IVC (the Inferior Vena Cava — the great vein carrying blood from the lower limbs and pelvis to the heart). This is done through a needle puncture in the groin.
Coronary heart disease is also a major cause of mortality. Obviously, the disease is pre-existing in these patients. Appropriate specialist care is needed, again obviously. It may be mentioned that almost all the risk factors for a heart attack are improved after bariatric surgery.
Among the surgical causes of death,
leaks take the cake. Apart from that, intra-abdominal abscesses and bowel obstruction following
gastric bypass or BPD/DS are important causes.
It has been said that most deaths following any surgery do not result from a single gigantic error, but rather from a series of small errors, each of which compounds and amplifies the complication leading to the patient’s demise. Suffice it to say that while the surgical complications mentioned above themselves are significant, they become lethal because of delayed diagnosis in two-thirds of cases. Negligence has been noted in nearly a third of such deaths.
As far as the surgical strategies to reduce mortality are concerned, we need to reduce leaks and obstructions and detect them early when they occur.
Leak prevention includes using staple-line buttresses, suturing,
avoiding too narrow a tube, and avoiding thermal injuries. Bowel obstruction prevention largely deals with closure of internal defects at the time of gastric bypass and avoiding the retrocolic approach.
References:
- Causes of 30-day bariatric surgery mortality: with emphasis on bypass obstruction– Mason EE, Renquist KE, Huang YH, Jamal M, Samuel I.
- The SOS Study: Sjöström
- The Pennsylvania bariatric mortality study
- Long-Term Mortality after Gastric Bypass Surgery: Ted D. Adams, et al.
- Medicolegal analysis of 100 malpractice claims against bariatric surgeons: Cottam D, Lord J, Dallal RM, Wolfe B, Higa K, McCauley K, Schauer P.
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