The calcium connection: why hip and knee replacements might increase the risk of heart attack
15 March 2016 | Editor
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Hip Replacements: short term increase in heart attack risk
A Dutch study of 95,000 Danes undergoing hip or knee replacements has shown in increased risk of heart attack in the 2 weeks following surgery for patients over the age of 60. The results also led to a recommendation that a prior heart attack in the year leading up to surgery should be a contraindication for knee and hip replacement operations.
People having hip replacements are 25 times more likely to have a heart attack in the fortnight after their operation, and those having knee replacements 31 times more likely.
What is unclear is why that is the case. The Dutch team considered the role of cutting into the bone, which may increase the risk of clot formation in the bone marrow, particularly with hip replacements.
We also know that the stress caused by the anaesthetic, the surgery and the anticipation of surgery may exacerbate any narrowing of the arteries that is already there. In addition, blood loss during surgery means that the heart may become deprived of oxygen – and if the heart is already struggling due to narrowed arteries, then surgery may take this to a dangerous level of oxygen deprivation.
The calcium connection
We can start to make sense of this by looking at some of the criteria that link hip and knee replacements with heart attacks. Hip and knee replacements are usually offered to people with osteoporosis, rheumatoid arthritis or osteoarthritis, where the joint has deteriorated due to combinations of inflammation, degradation and weakness. Underlying each of these conditions is a pH imbalance, where excess acidity is sent to the cartilage and fascia (both types of connective tissue) in the area of the joint. Calcium is then often drawn out of the bone and pushed into the tissue to try and buffer some of the acidity.
Now let's consider what causes heart attacks. Usually there will already be narrowing of the arteries by a mixture of cholesterol and calcification. We do not know why these deposits form, but one theory is that the mixture forms a kind of putty where the artery wall has weakened, and many talk about the body "dumping" excess calcium and cholesterol into the arteries. Blood clots can form where some of this putty-like mixture breaks off, which then may cause a blockage in the artery and prevent it supplying the heart with oxygen via the blood. If heart tissue goes too long without oxygen, then the tissue can die, and this is what happens during a heart attack.
In both situations, a holistic approach would seek to improve the pH and basic underlying conditions in the tissue, be it artery walls or joint cartilage and fascia, and at the same time use magnesium alongside endocrine support to help reposition calcium into the blood and bones. Magnesium is key to calcium placement in the body.
The medical approach, however, is usually to prescribe calcium supplementation for those with joint problems, and focus on reducing cholesterol intake for those with narrow arteries - in both cases ignoring the issue of calcium misplacement.
Calcium carbonate associated with increased risk of heart attack
Not only does this make little biochemical sense, the form of calcium prescribed is usually calcium carbonate – or chalk!– which is poorly absorbed and utilised in the body, and may be worsening both the arteries and the joints. Perhaps unsurprisingly, calcium supplementation was last year shown to increase the risk of heart attack by 30%.2 An earlier German study on the effects of calcium carbonate on cardiovascular calcification and bone density concluded:“This 2 year study shows that calcium carbonate use is continuously associated with progressive arterial calcification in haemodialysis patients. In addition, it suggests that it is also associated with decreased trabecular bone density.3
The Dutch study of hip and knee replacement patients did not take into account medication or supplementation taken, so we cannot know how many of the patients had been prescribed calcium carbonate supplements as part of their treatment for osteoporosis or arthritis.
Finally, we know from a UK report that stress can increase arterial calcification - so anxiety about the operation, and also the stress of the anaesthetic and operation itself, may well be adding to this picture.4
A naturopathic approach
So a possible explanation is that people with a history of over-acidity, leading to the drawing of calcium from the bones and into the tissue- to the extent that they end up needing a hip or knee replacement - may also be at greater risk of calcification in the arteries. Calcium supplementation would seem to exacerbate this risk, and now we see that surgery under anaesthetic increases it further, possibly through mechanisms of stress and oxygen deprivation.
Rather than let things get this far, why not add in more sensible biochemical support in the form of magnesium citrate, an alkalising and hydrating diet and some appropriate endocrine support - bearing in mind the role of the thyroid and parathyroid glands in calcium placement. High-concentration phosphatidyl choline has also been shown to increase cholesterol's solubility and so reduce the build-up of arterial plaque that narrows the arteries. Phosphatidyl choline is most commonly taken in the form of lecithin granules.