Primary insomnia means difficulty sleeping not due to another medical or sleep disorder. It's a common problem but has not been conclusively linked with increased risk of medical illness. It has been shown to increase risk of depression. Part of what I do when I treat chronic insomnia is to explain that insomnia by itself is not medically dangerous. The studies that have shown links between insomnia and medical problems have not distinguished primary from secondary insomnia. Insomnia secondary to obstructive sleep apnea (OSA) can increase risk for cardiovascular (CV) disease, but it's the OSA, not the insomnia that is raising the CV risk.
Here is an article confirming what's already known about primary insomnia and high blood pressure. The results showed no link between insomnia and high blood pressure, even for 'severe' insomnia.