Surgery and Stents

March 1, 2009

Stents are the ingenious hi-tech devices implanted in blocked coronary arteries by cardiologists, our high priests of interventional medicine. In the last 3-5 years we’ve learned unfortunately that coronary stents are not the panacea once hoped for. A major problem with stents is that they tend to become blocked off themselves unless anti-platelet medication, such as Plavix, is taken, for months or even years.

One of the main purposes of pre-surgery evaluation is to find out whether a patient has coronary artery disease and is therefore at risk for having a heart attack or other heart complication during or after surgery. We used to assume that  offering these patients stents (‘re-vascularisation’) would protect them from these kinds of heart problems.

In fact, studies have shown that patients who’ve been very recently ‘stented’ often have worse outcomes. For major surgery, anti-platelet drugs are usually stopped, in order to prevent bleeding. Unfortunately stopping these medications, combined with the complex effects of surgery on blood clotting, leads to a much greater chance that the stent, and therefore the artery, will block off, thereby causing the cardiac complication we were trying at all costs to avoid.

Guidelines from the American College of Cardiology, the American Heart Association, and the American Society of Anesthesiologists, now recommend postponing major elective surgery in which there is significant risk of bleeding, in patients with new coronary stents.

If you have a bare-metal stent the minimum recommended wait is 4-6 weeks. If you have a drug-eluting stent the wait is 12 months after implantation.

Decision-making (e.g. when to have the surgery, when to stop or continue medications) can be quite complex in this situation. Very often, surgery cannot be postponed, and the risks have to be carefully weighed to make a good choice.

What You Should Do

Make sure your anesthesiologist and your surgeon know that you have a coronary stent, when it was put in, what type it is, and what medications you are taking.

Assessing risks and benefits, to guide decision-making about going forward (or postponing) surgery, and about stopping or continuing anti-platelet drugs will involve a discussion between your surgeon, your anesthesiologist, and your cardiologist. With your input of course.

Reference

Practice Alert for the Perioperative Management of Patients with Coronary Artery Stents: A Report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology: January 2009 – Volume 110 – Issue 1 – pp 22-23. Link.

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Questioning the need for blood transfusion

October 29, 2008

Have Jehovah’s witnesses been right all along? About blood transfusion, that is.

There is increasing evidence that a “liberal” approach to the transfusion of blood is the wrong approach. For instance, transfusion seems to increase the risk of infection. But it’s not the kind of infection that most people worry about, dread viruses like hepatitis or HIV. Rather, transfusion inhibits the immune system and leads to higher rates of so-called nosocomial, or hospital-acquired, bacterial infection (bloodstream infections, pneumonia, urinary infection).

There’s even a seldom appreciated increased risk of acquiring cancer over subsequent years.

A new retrospective study has shown that banked blood stored for more than 4 weeks is associated with more infection in the patients who receive it. Blood is scarce and expensive, and most blood banks store it for up to 42 days before administration.

What’s the right perspective? Except for certain religious groups blood transfusion isn’t evil and, as always, an appreciation of risks and benefits is necessary. Blood can be life-saving. And patients with severe heart or lung disease, for example, do poorly without transfusion in circumstances that healthier people easily tolerate.

What you can do

  1. If you are in a position to do so – e.g. before elective joint surgery – it’s wise to ask a few questions of your doctor about blood transfusion. The right questions, plus a lot useful information, is contained in a nice booklet (PDF) put out by the Society for Advancement of Blood Management.
  2. If you are about to undergo surgery in which significant blood loss is expected, your hemoglobin level should be checked ahead of time. A low level (anemia) detected only in hospital could lead to an unnecessary blood transfusion, avoidable through the administration of iron, by mouth, or an injection of erythropoietin, a drug that stimulates the body to produce red blood cells.