Archive for June, 2009

From the Associated Press:

Heart attack survivors are again being enrolled in a controversial federal study of an alternative treatment while the government investigates whether they were told enough about possible health risks.

The $30 million study, with 1,500 participants so far, is one of the largest alternative medicine experiments ever launched. It tests high doses of vitamin and mineral supplements and chelation, a treatment used for lead poisoning that has not been proved safe or effective for heart disease.

Researchers suspended enrollment last August, when the federal Office of Human Research Protections began a probe into whether the people in the study were being fully informed of risks and adequately protected.

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From PTCA.org comes an excellent article converning the use of IVUS (emphasis mine):

A study, published in the current issue of JACC Interventions, details 120 drug-eluting stent cases as viewed by intravascular ultrasound (IVUS) in order to examine characteristics that may lead to in-stent restenosis (ISR) or stent thrombosis.

Underexpansion of stents, both drug-eluting and bare metal, has been long identified as a significant predictor of adverse clinical events. Prominently discussed by Dr. Antonio Colombo in the early days of stenting, inadequate expansion of the stent struts is known to increase these problems.

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Fractional Flow Reserve, or FFR, is a guide wire-based procedure. Its utilility is that it can accurately measure blood pressure and flow rate through a specific part of the coronary artery. Is is performed through a standard diagnostic catheter during the actual coronary cathaterization. Using Fractional Flow Reserve, the interventinalist can assess whether or not to perform angioplasty or stenting on “intermediate” blockages – blocakges that may or may not cause angina symptoms or lead to serious ischemic events.

The entire point of using a stent in the coronary arteries is to increase blood flow to the heart. However, a number of studies have shown that if a “functional measurement”, such as Fractional Flow Reserve, indicates the flow is not significantly obstructed, the blockage or lesion does not need to be revascularized (angioplasty) and the patient can be treated safely with medical therapy.

The Interventinalist’s tendency to stent is well documented. Some more aggressive than others. In the case of my cardiologist, if he notices a blockage of 75% or greater, he will stent it. Some cardiologists will stent a 50% blockage. But what if FFR indicated that an intervention won’t have a significant impact on a particular blockage? Being able to better select cases not only saves health care costs, but contributes to more appropriate patient care.

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