**6.3 Arterial hypertension**

The available data on NFC in arterial hypertension is scanty, but microangiopathy has been demonstrated in different studies. Decreased capillary density has been described as being related with the mean diastolic pressure and the blood hyperviscosity [61]. These abnormalities are even more severe in the hypertensive elderly population, once capillary loops become longer and narrower. A slow flow capillary sludge is usually found in individuals with a hypertensive systolic pressure. Capillary density is reversible, as it has been proved in different ethnic groups that a reduction in ingested salt would result in augmented capillary density [62]. A different study revealed a significant narrowing of arterial loops in patients with either arterial hypertension or prehypertension stage, regardless of their age [11].
