Lipoprotein(a) and small LDL

It's been my suspicion for some time that the combination of lipoprotein(a), or Lp(a), in combination with small LDL particles is a really bad risk for heart disease. People with this combination seem to have much higher heart scan scores for age than others. This seems to be a pattern that we'll see in the occasional woman less than 50 years old who already has a high heaert scan score. (It's unusual for women to have detectable coronary plaque before age 50.)

Very little data exists to support this idea and we are in the process of performing a small study to see whether it's true or not. My gut sense: it's among the most potent causes of coronary plaque around.

Case in point: Even though I spend a great deal of my time and energy advocating heart disease prevention, I still maintain my hospital privileges and skills. I had to cover one of the emergency rooms in town this past weekend (a requirement to maintain my hospital privileges).

One of the patients I saw was a 40-year old man--we'll call him Roland-- suffering a very large heart attack, a so-called "anterior myocardial infarction", or a heart attack involving the most important front portion of the heart. Thankfully, he came to the ER within 45 minutes after his chest pain started. The situation was immediately obvious and I was called to the ER. We quickly took him to the cardiac catheterization laboratory and put a stent in the left anterior descending artery and flow was restored. His chest pain dissipated over the next few minutes.

Nonetheless, Roland was left with a large area of reduced contraction of his heart muscle. Only time will tell how much recovery he'll have.

Roland was extremely lucky. The majority of people with closure of the artery that he'd experienced die within minutes. He did, in fact, "arrest" briefly, i.e., his heart became electrically unstable, though he recovered promptly.

Along with the multiple tubes of blood we required to run tests for his heart attack management, we had Roland's lipids and other measures sent off, as well. Wouldn't you know: Lp(a) and small LDL. This may have accounted for a heart attack at age 40.

Keep a lookout for this when you have lipoprotein testing. Conveniently, niacin can be used to treat both patterns, though higher doses are generally required for the Lp(a) part of the pattern. It's also my belief that the sort of Lp(a) measurement performed by the Liposcience laboratory (www.liposcience.com) is superior. They use a particle number based measure, not a weight-based measure. It is therefore independent of particle size, which can vary. Further work will, I believe, reveal some very important insights into the dreaded Lp(a).

Comments (1) -

  • wccaguy

    10/20/2007 4:18:00 PM |

    Just getting around to reading some of your older blog posts.

    Although I'm not completely certain, it's my impression that Marcovina was a student of Professor Sally McCormick of Otago University in New Zealand.

    http://biochem.otago.ac.nz/staff/mccormick/smccormick.html

    Notice they both participated in this seminal article.

    Sharp RH, Perugini MA, Marcovina SM, McCormick SPA: Structural features of apolipoprotein B synthetic peptides that inhibit lipoprotein(a) assembly. J Lipid Res 45:2227-2234, 2004.

    I'm very certain that Rebeca Sharp was a student at Otago.

    More importantly, Sally McCormick has applied for a patent mirroring the article title linked to above at wipo.int.  Don't have the link handy.

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