Now seems like a good time to revisit a study presented in late 2005 at the European Society of Cardiology meetings in Stockholm. In that study, investigators report that patients with intermediate blockages in their coronary arteries (that is, blockages of about 50 - 75%,) but without evidence of angina on stress testing, do not benefit from stenting procedures.
The DEFER study evaluated 325 patients with intermediate blockages. If testing in these patients did not show evidence that the blockages were significantly obstructing blood flow, these patients were randomized to receive either stent therapy or medical therapy alone. After 5 years, patients who received stent therapy had no reduction in heart attacks, the need for bypass surgery, or death as compared to the medically treated patients. The investigators concluded that patients with these "functionally insignificant" partial blockages had an excellent prognosis with medical therapy alone (i.e., their risk of heart attack or death was less than 1% per year,) and that risk was not reduced further with stenting.
DrRich comments:
Current guidelines endorsed by the American Heart Association recommend that, before stenting is performed, a stress test be done to look at whether a partial blockage in a coronary artery is capable of producing ischemia. That is, a stress-perfusion study ought to be performed to assess the true functional significance of the partial blockage, to see whether it is capable of actually obstructing blood flow. So the results of the DEFER study should not be surprising or controversial - the DEFER study merely supports the recommendations made in current AHA guidelines.
However, especially in the era of drug-coated stents and especially in the US, cardiologists have gotten into the habit of simply throwing a stent at every coronary artery lesion they see, as long as it "might" be significant. The reasons they give for doing this include: a) drug coated stents are really, really effective; b) the patient is right here in the cath lab, right now, today - and you want me to pull out the catheters, schedule a stress test, and then (if the stress test is positive) reschedule another cath procedure? Talk about inefficiency!
Both of these excuses are subject to criticism. Even drug-eluting stents (DES) carry risks, including (apparently) the risk of late, sudden occlusion. And in most circumstances, stress-perfusion testing ought to be done before a cath procedure (because, if it is negative, the cath in most cases would not be necessary.)
All of this is not to say that stents are always the wrong thing to do with intermediate coronary artery lesions. But if you are scheduled for a cath procedure and possibly a stent, you might want to discuss with your cardiologist ahead of time what the plan of attack will be if an intermediate blockage is found, and get an idea from him/her what the rationale is for their approach. If the answer does not make sense (or if they just get defensive about it,) you may want to get a second opinion.
