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Cardio Notes: Vitamin D Lipid Role Unclear

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An analysis of laboratory results suggested that treating low serum vitamin D levels with supplements may not have an impact on cholesterol. Also, ticagrelor (Brilinta) goes head to head with clopidogrel in patients with peripheral arterial disease, and transcatheter aortic valve implantation (TAVI) moves into lower-risk patients.

Vitamin D May Not Aid Lipid Profile

Even though vitamin D deficiency has been associated with both dyslipidemia and cardiovascular disease in cross-sectional studies, correcting a vitamin D deficiency does not appear to improve an individual's lipid parameters, according to study in Circulation.

Harvey Kaufman, MD, of Quest Diagnostics in Madison, N.J., and colleagues examined more than 4 million patient laboratory results. A cross-sectional analysis confirmed that low serum levels of 25-hydroxyvitamin D were associated with higher levels of total cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides, and lower levels of high density lipoprotein (HDL) cholesterol.

In an analysis of patients with more than one test result, however, increasing serum vitamin D levels from less than 20 ng/mL to at least 30 ng/mL -- compared with remaining at less than 20 ng/mL -- was associated with a slight increase in HDL cholesterol (+0.42 mg/dL, P=0.02), but no significant change in levels of LDL cholesterol (+0.32 mg/dL, P=0.06) and triglycerides (+0.04 mg/dL, P=0.97).

The researchers said a definitive answer to whether vitamin D supplementation will affect lipid parameters requires a large randomized controlled trial.

"However," they wrote, "until such results are available, this study challenges the utility of extrapolating the cross-sectional associations between vitamin D and lipids into a rationale for treating patients with vitamin D supplements to improve the lipid profile."

Ticagrelor versus Clopidogrel in PAD

AstraZeneca will put its antiplatelet ticagrelor (Brilinta), which was approved last July for use in patients with acute coronary syndromes, up against clopidogrel in patients with peripheral arterial disease (PAD).

The EUCLID trial has a target enrollment of 11,500 patients, 50 and older, who will be randomized to ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily. The primary outcome will be a composite of cardiovascular death, myocardial infarction (MI), and ischemic stroke.

EUCLID is part of the larger PARTHENON program designed to evaluate ticagrelor in more than 51,000 patients worldwide. The first trial in the PARTHENON program was PLATO, in which ticagrelor significantly reduced the rate of cardiovascular death, MI, and ischemic stroke compared with clopidogrel in patients with acute coronary syndromes.

The principal investigator of EUCLID is William Hiatt, MD, of the University of Colorado in Denver.

SCAD Patients May Need Close Follow-up

The clinical features and prognosis of spontaneous coronary artery dissection (SCAD) have not been well described, but a single-center study reported in Circulation suggested that about half of patients with the condition will have a life-threatening event within 10 years.

Rajiv Gulati, MD, PhD, of the Mayo Clinic in Rochester, Minn., and colleagues identified 87 patients with angiographically confirmed SCAD treated at their center. The mean age of the patients was 42.6 and 82% were women.

Extreme exertion at the onset of SCAD was more common in men than in women (44% versus 3%, P<0.001), and about half of the patients (49%) presented with ST-segment elevation MI.

In general, initial conservative treatment and coronary artery bypass graft were associated with an uncomplicated initial hospital stay, but percutaneous coronary intervention resulted in a high rate of technical failure (35%).

During a median follow-up of nearly 4 years, 15 patients (17%) had a recurrence of SCAD, all of them female. The researchers estimated that 47% of the patients who have a major adverse cardiovascular event within 10 years, which "together with the unpredictability in timing of SCAD recurrence (ranging from 3 days to 12 years in this series) highlight the need for both close and long-term follow-up," they wrote.

TAVI to be Tested in Lower-Risk Patients

Medtronic, maker of the CoreValve prosthesis, announced that it has started the SURTAVI trial to compare the use of TAVI with its valve with surgical aortic valve replacement in patients with severe aortic stenosis.

Previous studies, including the PARTNER trial, have evaluated TAVI in patients who were either inoperable or who carried a high risk for surgical complications. SURTAVI will include patients with an intermediate surgical risk, defined as a Society of Thoracic Surgeons' mortality risk of 4% to 10%.

The first procedures in the trial have been completed at Rigshospitalet Copenhagen University Hospital by interventional cardiologist Lars Søndergaard, MD, and cardiothoracic surgeon Daniel Steinbrüchel, MD, DMsc.

The trial is expected to involve up to 75 centers, with some likely in the U.S., according to a press release from the company, and is expected to enroll about 2,500 patients. The primary outcome of the non-inferiority trial is the 2-year rate of all-cause mortality or major stroke.

Although the Edwards SAPIEN valve has been approved for use in the U.S., the CoreValve prosthesis has not.