Clinical Management of Resistant Hypertension: Practical recommendations from the Italian Society of Hypertension (SIIA)

Resistant Hypertension: An Incurable Disease or Just a Challenge For Our Medical Skill?

Resistant hypertension is classically defined as a clinical condition in which target blood pressure values of 140/90 mmHg are not achieved despite an optimal pharmacological therapy of at least three antihypertensive drugs, including a diuretic. The aim of this review is to give an outline of the nosography of this disorder, highlighting the differences between true and apparent resistant hypertension. Since the proportions of patients who can be defined as resistant to antihypertensive treatment is elevated, this distinction is mandatory in order to identify only those who need special clinical attention and, possibly, newer non-traditional techniques. While at first glance resistant hypertension may appear as an insuperable problem, an accurate clinical work-up of these patients, aimed at excluding reversible causes and optimizing pharmacological treatment, represents an effective solution in most cases.

Endothelium-dependent and -independent vasorelaxant actions and mechanisms induced by total flavonoids of Elsholtzia splendens in rat aortas

Elsholtzia splendens (ES) is, rich in flavonoids, used to repair copper contaminated soil in China, which has been reported to benefit cardiovascular systems as folk medicine. However, few direct evidences have been found to clarify the vasorelaxation effect of total flavonoids of ES (TFES). The vasoactive effect of TFES and its underlying mechanisms in rat thoracic aortas were investigated using the organ bath system. TFES (5-200mg/L) caused a concentration-dependent vasorelaxation in endothelium-intact rings, which was not abolished but significantly reduced by the removal of endothelium. The nitric oxide synthase (NOS) inhibitor N(ω)-nitro-l-arginine methyl ester (100μM) and the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,2-α]quinoxalin-1-one (30μM) significantly blocked the endothelium-dependent vasorelaxation of TFES. Meanwhile, NOS activity in endothelium-intact aortas was concentration-dependently elevated by TFES. However, indomethacin (10μM) did not affect TFES-induced vasorelaxation. Endothelium-independent vasorelaxation of TFES was significantly attenuated by KATP channel blocker glibenclamide. The accumulative Ca(2+)-induced contraction in endothelium-denuded aortic rings primed with KCl or phenylephrine was markedly weakened by TFES. These results revealed that the NOS/NO/cGMP pathway is likely involved in the endothelium-dependent vasorelaxation induced by TFES, while activating KATP channel, inhibiting intracellular Ca(2+) release, blocking Ca(2+) channels and decreasing Ca(2+) influx into vascular smooth muscle cells might contribute to the endothelium-independent vasorelaxation conferred by TFES.