How can arterial stiffness be confirmed and treated, and is Vitamin K or a diet high in Vitamin K beneficial?

Confirming and Treating Arterial Stiffness

Measure arterial stiffness using carotid-femoral pulse wave velocity (cfPWV), the gold standard method, and consider vitamin K supplementation as it has been shown to prevent progression of arterial stiffness in deficient patients. 1, 2

Diagnostic Confirmation

Carotid-femoral PWV is the definitive measurement method for assessing large artery stiffness, with the American Heart Association providing a Class IIa, Level A recommendation for its use in clinical settings. 1, 3 This technique measures the speed at which the arterial pulse propagates between the carotid and femoral arteries, with higher velocities indicating greater stiffness. 1

Measurement Techniques

• Applanation tonometry is the most widely used method, capturing pulse waveforms at two arterial sites and calculating velocity as distance/time (m/s). 3, 4
• Doppler ultrasound can also measure PWV by tracking pulse wave propagation along arterial segments. 3
• Advanced ultrasound techniques including pulse wave imaging and shear wave elastography are emerging methods that provide direct visualization of wave propagation and tissue stiffness. 1
• Distensibility measurements using ultrasound to assess diameter changes in response to pressure can calculate PWV through the Bramwell-Hill equation. 1

Important Caveats

• PWV measurements are pressure-dependent, capturing stiffness at specific pressure levels (typically diastolic pressure when tracking the early systolic wave front). 1
• Measures like augmentation index are not true stiffness parameters but reflect multiple factors including wave reflection. 1
• The ACC/AHA states that arterial stiffness measures outside research settings are NOT recommended for routine cardiovascular risk assessment (Class III recommendation). 3

Treatment Approaches

Vitamin K Supplementation

Vitamin K supplementation prevents progression of arterial stiffness in vitamin K-deficient patients. 2 The most compelling evidence comes from a 2023 randomized controlled trial in kidney transplant recipients:

• Menaquinone-7 (vitamin K2) at 360 μg/day for 12 weeks prevented PWV progression (-0.06 ± 0.26 m/s) compared to placebo (+0.27 ± 0.43 m/s; P=0.010). 2
• This effect occurred through improved vitamin K status, reducing inactive matrix Gla-protein (dp-ucMGP) levels by -385 pmol/L versus +39 pmol/L in placebo. 2
• The mechanism involves activation of MGP, a potent vascular calcification inhibitor that requires vitamin K for carboxylation. 5, 6

Who Should Receive Vitamin K

Screen for vitamin K deficiency by measuring plasma dp-ucMGP levels (deficiency defined as ≥500 pmol/L). 2 High dp-ucMGP levels are independently associated with increased arterial stiffness across multiple populations including heart failure patients. 5, 6

Dietary Considerations

• Foods high in vitamin K include green leafy vegetables (vitamin K1/phylloquinone) and fermented foods (vitamin K2/menaquinones). 7
• While dietary vitamin K may theoretically help, the clinical trial evidence specifically used high-dose vitamin K2 supplementation rather than dietary modification alone. 2
• Critical warning: Patients on warfarin should not increase vitamin K intake, as warfarin use is associated with increased arterial stiffness through inhibition of MGP activation. 6

Additional Treatment Strategies

Beyond vitamin K, the most effective non-pharmacologic interventions are:

• Regular aerobic exercise combined with sodium restriction (such as the DASH diet) is probably the most effective way to counteract increased large artery stiffness. 4
• Blood pressure control with antihypertensive medications reduces PWV primarily by lowering mean arterial pressure and unloading the vessel wall, though these drugs don't specifically target wall stiffness. 4

Mechanisms of Vitamin Action

Multiple vitamins affect arterial stiffness through various pathways: antiatherogenic effects, endothelial function improvement (vitamins A, C, D, E), metabolic profile enhancement (vitamins A, B12, C, D, K), RAAS inhibition (vitamin D), anti-inflammatory effects (vitamins A, D, E, K), antioxidant activity (vitamins A, C, E), and reversing arterial calcification (vitamin K). 7 However, vitamin K has the strongest specific evidence for preventing arterial stiffness progression. 2