In the news: Omega-3s Decrease Arterial Stiffness; May Reduce Hospital Stay Post Cardiac Surgery

Arterial Elasticity: Predictor of CV Mortality

Large arteries moderate increases in systolic pressure and maintain sufficient diastolic pressure to perfuse the heart. With age and disease, these arteries lose their natural elasticity leading to high systolic and low diastolic blood pressure levels.

That loss of elasticity, or arterial stiffness, is now considered an increasingly important, independent predictor of cardiovascular mortality in the elderly, hypertensives, diabetics, and renal failure patients as well as in the general population.

Arterial Stiffness’ Role in Ocular Conditions?

Arterial stiffness may also play a role in some ocular diseases. It’s been reported that patients with AMD have increased systemic arterial stiffness compared with age-matched controls, for example. Arterial stiffness indices have also been found to be abnormal in patients with branched retinal vein occlusion vs. healthy and hypertensive controls. And in a recent study (1), greater arterial stiffness was associated with both glaucoma and normotensive glaucoma in diabetics vs. age matched controls.

PWV for Evaluating Arterial Stiffness

Among the different methods of evaluating arterial stiffness, the most widely used in the literature is pulse wave velocity (PWV). PWV measures the rate of pressure waves moving down a vessel, specifically in the area running from the common carotid artery to the common femoral artery.

In stiffer arteries the speed at which the pressure wave moves increases, as does the speed at which reflected pressure waves move back toward the heart. When these pressure waves travel faster, the cardiovascular system has to work harder.

Supplemental Omega-3s Improve Artery Elasticity

Researchers from the University of Pennsylvania College of Medicine evaluated the effect of omega-3 supplements on arterial stiffness in both younger (aged 21 – 35, mean 25 yrs) and older (aged 60 – 80, mean 66 yrs) healthy men and women (2). The participants received two 1 gram capsules of omega-3 fatty acids (465 mg EPA and 375 mg DHA) twice daily for 12 weeks. Central arterial stiffness was measured by carotid-femoral PWV, and arterial wave reflection by central augmentation index.
 
Carotid-femoral PWV and central augmentation index were greater in the older group (988 + 65 cm/sec and 33 + 2%) than in young adults (656 + 16 cm/sec and 3 + 4%; both P < 0.05) before the intervention.

Omega-3 supplementation significantly decreased PWV by 9% in older, but not younger subjects. Central augmentation index and arterial blood pressure were unchanged. The mechanism underlying reduced central arterial stiffness with omega-3 supplementation is not known, but may be independent of effects on arterial blood pressure or arterial wave reflections. Previous research found improved arterial stiffness and a parallel anti-inflammatory effect with omega-3 supplementation in adults with metabolic syndrome. Larger and longer controlled trials are warranted.

Pre-Surgical omega-3s May Reduce Hospital Stay

A new meta-analysis and systematic review (3) which included 11 RCTs and 1,038 patients, found no effect of pre-operative omega-3son the primary outcome of length of stay in the intensive care unit.

However, the analysis did find changes in pre-defined secondary outcomes: omega-3 supplements reduced overall length of hospital stay by up to 2.4 days (P = 0.010). A 22% odds reduction in the occurrence of post-operative atrial fibrillation was also noted (P = 0.004). The results are in agreement with a 2013 meta-analysis (4), which found pre-operative omega-3 dosing significantly prevented post-operative atrial fibrillation in patients undergoing cardiac surgery, especially coronary artery bypass surgery.

References:

1. Shim SH, et al. The role of systemic arterial stiffness in open-angle glaucoma with diabetes mellitus. Biomed Res Int. Epub Oct 18, 2015.
2. Monahan KD, et al. Effect of omega-3 polyunsaturated fatty acid supplementation on central arterial stiffness and arterial wave reflections in young and older healthy adults. Physiological Reports, 3:e12438, 2015.
3. Langlois P, et al. Omega-3 poly-unsaturated fatty acids in cardiac surgery patients: An updated systematic review and meta-analysis. Clin Nutr. Epub May 27, 2016.
4. Costanzo S, et al. Prevention of postoperative atrial fibrillation in open-heart surgery patients by preoperative supplementation of n-3 polyunsaturated fatty acids: an updated meta-analysis. J Thorac Cardiovasc Surg. 146:906-11, 2013.