A Diagnostics & Imaging Week

The American Diabetes Association (ADA; Alexandria, Virginia) and the American College of Cardiology (Washington) have issued a consensus statement saying that the measurement of LDL particle number by nuclear magnetic resonance (NMR) is one of the more accurate ways to evaluate cardiometabolic risk (CMR).

The study, published in the April Diabetes Care, reinforces that LDL cholesterol may not be the best way to quantify a patient's risk for cardiovascular disease (CVD). CMR is associated with Type 2 diabetes and CVD-obesity, insulin resistance, hyperglycemia and hypertension are risk factors that often cluster together, the organizations note in a statement.

Robert Rosenson, MD, director of Lipoprotein Disorders and Clinical Atherosclerosis Research at the University of Michigan School of Medicine (Ann Arbor) and presenter at a consensus panel meeting, said that ApoB and LDL particle concentration "appear to be more closely associated with these markers of CMR than LDL cholesterol or non-HDL cholesterol. Subsequently, lipoprotein abnormalities are commonly found in patients with CMR.

And ApoB and LDL particle number by NMR "appear to be more discriminating measures of the adequacy of LDL lowering therapies than are traditional LDL and HDL cholesterol measures."

He added: "Several studies have shown that LDL cholesterol (LDL-C) poorly characterizes lipid abnormalities in patients with cardiometabolic risk. Additionally, LDL-Pconcentrations, compared to LDL-C and non HDL-C, have been shown to be stronger predictors of cardiovascular risk."

The only test that quantifies LDL particle number using NMR is the NMR LipoProfile test, developed by LipoScience (Raleigh, North Carolina).

"This consensus statement further demonstrates the critical role that the NMR LipoProfile test can play for the millions of people with diabetes or cardiovascular disease risk," said Rick Brajer, president/CEO of LipoScience. "Measuring LDL particle number by NMR presents physicians and patients with the opportunity to better manage cardiometabolic risk."

Lung capacity: affecting inhalable insulin?

In another study related to diabetes, appearing in the April issue of Diabetes Care, researchers are advising the developer of inhaled insulin to consider the issue of declining lung capacity in patients with Type 2 diabetes.

While the recommendation is to take diminished lung capacity into consideration in clinical trials with these patients, the finding may indicate another barrier for developing the inhalable product an effort already exited by three companies over the past year.

The research, part of a larger investigation known as the Atherosclerosis Risk in Communities (ARIC) study, confirmed previous indications that the lung is a target organ for diabetic injury and that lung abnormalities accelerate once diabetes takes hold. Previous research by the same authors established that decreased lung capacity precedes and may predict a diagnosis of diabetes.

The study found that people with Type 2 diabetes experience a more rapid decline in forced vital capacity, the measure of how well the lungs fill with air, than people who did not have diabetes. Though all people experience a decline in forced vital capacity as they age, those with diabetes appear to undergo a more rapid loss that appears before the diabetes diagnosis, and this accelerates after the disease sets in.

"Think of the lung as a crime victim who unwittingly abets the perpetrator to hasten the demise of the host," wrote Dr. Connie Hsia, of the Department of Internal Medicine at the University of Texas Southwestern Medical Center (Dallas), in an editorial accompanying the study. She suggested that the loss of pulmonary function could add to diabetic morbidity and mortality, and raised concerns about the potential use of inhaled insulin, since it may "trigger or exacerbate pulmonary dysfunction."

"Manufacturers of inhaled insulin should find these data useful as they study potential long-term effects of their product on lung function," said Fred Brancati, MD, one of the study's lead researchers. "The results suggest that doctors and patients should keep an eye on the literature about diabetes and the lung down the road, since there's a stronger connection than we previously thought."

The researchers hypothesize that the primary activity in this association is a stiffening of lung tissue resulting from high blood sugar levels, or because the fat tissue in the chest and abdomen may confine the lungs more in people with diabetes.

They concluded the study with this advice to clinicians: to pay heightened attention to pulmonary function in patients with Type 2 diabetes.

CT dose-reduction course offered

CVCTA Education (San Francisco) reported the introduction of an education program intended to help physicians reduce the radiation dose to patients during a CT Angiogram (CTA), avoiding making these doses significantly higher than needed and creating a downstream cancer risk. CVCTA Education addresses this problem with its new LOW DOSE initiative, augmenting CVCTA's dose reduction curriculum.

CVCTA Education's LOW DOSE initiative follows a simple mnemonic:

• Length of scan minimized.

• Optimized X-ray parameters and gating technique to the individual.

• Working with vendors to optimize the system.

• Dose Modulation.

• Operator Training.

• Scrutinize the effective dose.

• Evaluate dose at regular intervals, implement changes to minimize.

CVCTA delivers its courses at centers in San Francisco, New York and Houston.