Twenty-Four-Hour Ambulatory Pulse Wave Analysis in Hypertension Management: Current Evidence and Perspectives

The predictive value of vascular biomarkers such as pulse wave velocity (PWV), central arterial pressure (CAP), and augmentation index (AIx), obtained through pulse wave analysis (PWA) in resting conditions, has been documented in a variety of patient groups and populations. This allowed to make appropriate recommendations in clinical practice guidelines of several scientific societies. Due to advances in technologies, largely operator-independent methods are currently available for estimating vascular biomarkers also in ambulatory conditions, over the 24 h. According to the acceptable accuracy and reproducibility of 24-h ambulatory PWA, it appears to be a promising tool for evaluating vascular biomarkers in daily life conditions. This approach may provide an opportunity to further improve the early cardiovascular screening in subjects at risk. However, concerning the clinical use of PWA over the 24 h in ambulatory conditions at the moment, there is no sufficient evidence to support its routine clinical use. In particular, long-term outcome studies are needed to show the predictive value of 24-h PWV, CAP, and AIx values, provided by these devices, over and beyond peripheral blood pressure, and to answer the many technical and clinical questions still open. To this regard, the VASOTENS Registry, an international observational prospective study recently started, will help providing answers on a large sample of hypertensive patients recruited worldwide.     

Switching from ACE inhibitors,beta-blockers,calcium antagonists or diuretics to candesartan improves efficacy and tolerability

OBJECTIVE: To evaluate the efficacy and safety of candesartan in patients previously treated with, but displaying adverse reactions to, ACE inhibitors, beta-blockers, calcium antagonists or thiazide diuretics. METHODS: 968 mild to moderate essential hypertensive patients (aged 18-74 years) entered an 8-week treatment period with candesartan 8 or 16 mg according to a multicenter, randomized, open-label, parallel-group design. After the first 4 weeks of treatment, candesartan was doubled in 33.6% of patients taking the 8-mg dose, in whom blood pressure was > 140/90 mmHg. RESULTS: Sitting diastolic and systolic blood pressures were significantly reduced (mean and 95% confidence interval) after 4 [3.7 (3.2-4.2)/8.9 (8.0-9.9) mmHg; n = 930] and even more after 8 [5.8 (5.4-6.3)/12.1 (11.1-13.0) mmHg; n = 890] weeks of treatment. The rate of improvement in the tolerability profile (success) was always greater than the rate of failure (93.3 vs 6.7% at the end of treatment). Adverse reactions amounted to 1125 at baseline, 129 at 4 weeks and 46 at 8 weeks of treatment. Adverse events to candesartan were reported in 2.7% of patients. Efficacy and safety were similar when data were analyzed taking into account the type of previous antihypertensive treatment. CONCLUSION: Candesartan is an effective and safe alternative to common antihypertensive drugs when they are not tolerated by patients.     

The trough:peak ratio and the smoothness index in the evaluation of control of 24 h blood pressure by treatment in hypertension

The duration and homogeneity of the antihypertensive effect of a drug are commonly quantified by computation of the trough:peak ratio (T/P) from 24 h ambulatory blood pressure recordings [i.e. the ratio of the reduction in blood pressure at the end of the interval between doses (trough) and the reduction in blood pressure at the time of the maximal effect of a drug (peak)]. Although it is widely employed, this index has a lot of limitations: it makes use of only a small portion of a 24 h blood pressure recording; individual T/P values do not have a normal distribution, unless responders at peak are selected; it bears no relation to 24 h blood pressure variability; peak changes in blood pressure are affected by a placebo effect and thus T/P needs correction for effects of placebo; peak and trough changes in blood pressure are reproducible over time but T/P is not; and, finally, it was shown in the SAMPLE study that T/P is not correlated to changes in left ventricular mass induced by treatment, and thus has a limited clinical value.     

Frovatriptan vs. other triptans for the acute treatment of oral contraceptive-induced menstrual migraine: pooled analysis of three double-blind,randomized, crossover,multicenter studies

Oral contraceptive-induced menstrual migraine (OCMM) is a particularly severe form of migraine triggered by the cyclic hormone withdrawal. To review the efficacy of frovatriptan vs. other triptans, in the acute treatment of OCMM through a pooled analysis of three individual randomized Italian studies. With or without aura migraineurs were randomized to frovatriptan 2.5 mg or rizatriptan 10 mg (study 1), frovatriptan 2.5 mg or zolmitriptan 2.5 mg (study 2), frovatriptan 2.5 mg or almotriptan 12.5 mg (study 3). All studies had a multicenter, randomized, double-blind, crossover design. After treating 1–3 episodes of migraine in 3 months with the first treatment, patients switched to the other treatment for the next 3 months. In this analysis, the subset of 35 of the 280 women of the intention-to-treat population taking combined oral contraceptives and experiencing a migraine attack during the withdrawal phase, were analyzed. The proportion of pain free and pain relief at 2 h were 25 and 51 % with frovatriptan and 28 and 48 % with comparators (p = NS). At 24 h, 71 and 83 % of frovatriptan-treated patients and 60 and 76 % of comparator-treated patients were pain free (p < 0.05 between treatments) and had pain relief (p = NS), respectively. Relapse at 24 and 48 h was significantly (p < 0.05) lower with frovatriptan (17 and 21 %) than with the comparators (27 and 31 %). Our results suggest that, due to its sustained antimigraine effect, frovatriptan may be particularly suitable for the management of OCMM than other triptans.     

Restless legs syndrome is not associated with migraine with aura: a clinical study

Based on recent data about the association between restless legs syndrome (RLS) and migraine, we performed an observational study on the occurrence of RLS in patients affected by “pure” migraine with aura (pMA). We recruited 63 patients (33 females and 30 males) affected by MA without other types of primary headache among all patients referred in five Italian headache centers in a 1-year period. The prevalence of RLS in pMA patients (9.5%) is similar to that observed in Italian headache-free subjects (8.3%). No significant differences were found between pMA patients with and without RLS about clinical features of MA attacks and systemic and psychiatric diseases were investigated. Moreover, no association appeared between RLS and familial cases of MA. Differently from migraine without aura, our data do not confirm the existence of an association between RLS and MA, not even when a genetic factor is involved.

     

Efficacy of frovatriptan in the acute treatment of menstrually related migraine: analysis of a double-blind,randomized, multicenter,Italian, comparative study versus zolmitriptan

Menstrually related migraine (MRM) is a particularly difficult-to-treat pain condition, associated with substantial disability. Aim of this study was to compare the efficacy and safety of frovatriptan and zolmitriptan in the treatment of MRM attacks, analyzing data from a multicenter, randomized, double blind, cross-over study. We analyzed the subset of 76 regularly menstruating women who participated in one head-to-head multicenter, randomized, double blind, cross-over clinical trial and who took the study drugs to treat MRM attacks. In a randomized sequence, each patient received frovatriptan 2.5 mg or zolmitriptan 2.5 mg: after treating three episodes of migraine in no more than 3 months with the first treatment, the patient had to switch to the other treatment. MRM was defined according to the criteria listed in the Appendix of the last Classification of Headache disorders of the International Headache Society. A total of 73 attacks, classified as MRM, were treated with frovatriptan and 65 with zolmitriptan. Rate of pain relief at 2 h was 52% for frovatriptan and 53% for zolmitriptan (p = NS), while rate of pain free at 2 h was 22 and 26% (p = NS), respectively. At 24 h, 74 and 83% of frovatriptan-treated and 69 and 82% of zolmitriptan-treated patients were pain free and had pain relief, respectively (p = NS). Recurrence at 24 h was significantly (p < 0.05) lower with frovatriptan (15 vs. 22% zolmitriptan). Frovatriptan proved to be effective in the immediate treatment of MRM attacks, similarly to zolmitriptan, but showed lower recurrence rates, and thus a better sustained relief.

     

Smooth blood pressure control obtained with extended-release felodipine in elderly patients with hypertension: evaluation by 24-hour ambulatory blood pressure monitoring

OBJECTIVE: To assess, by smoothness index (SI), distribution of the antihypertensive effect of extended-release (ER) felodipine over 24 hours in elderly patients with hypertension. METHODS: After a 4-week washout phase, 35 elderly patients (mean age 69 +/- 4 years) with mild-to-moderate hypertension received 2 weeks' treatment with ER felodipine 5mg once daily. The dosage of ER felodipine was doubled to 10 mg/day and given for a further 2 weeks in non-responders (sitting clinic blood pressure > 140/90mm Hg). The study had an open-label design with no placebo control. After each period, clinic and ambulatory blood pressures were measured. Trough-to-peak (T/P) ratio was computed by dividing the blood pressure (BP) change at trough (22 to 24 hours after drug intake) by the change at peak (2 adjacent hours with a maximal BP reduction between the second and eighth hour after drug intake). SI was calculated as the ratio between the average of the 24, hourly, treatment-induced BP changes and its standard deviation. RESULTS: After the initial 2-week treatment period, clinic and 24-hour ambulatory BP values were higher in non-responders (145 +/- 11/87 +/- 8 and 135 +/- 17/80 +/- 6mm Hg, respectively) than in responders (133 +/- 6/81 +/- 3 and 130 +/- 9/77 +/- 7mm Hg). In non-responders, clinic and 24-hour BP values were lowered after a further 2 weeks of treatment with ER felodipine 10 mg/day (128 +/- 11/78 +/- 6 and 128 +/- 12/75 +/- 5mm Hg). SI was high in responders (0.8 +/- 0.8/0.7 +/- 0.7 for systolic/diastolic BP) and low in non-responders (0.5 +/- 0.6/0.3 +/- 0.6) during the first 2-week treatment period. It increased in non-responders after an additional 2 weeks of treatment with ER felodipine 10 mg/day (1.0 +/- 0.8/0.7 +/- 0.6). Median T/P ratios were 0.73 and 0.61 (systolic BP and diastolic BP) in responders and 0.41 and 0.61 in non-responders after 2 weeks of treatment. At variance with SI, T/P ratios did not increase in non-responders after doubling the dosage of ER felodipine (0.34 and 0.18). ER felodipine did not increase 24-hour heart rate. A total of nine adverse events were recorded in six patients (17%), but no patients withdrew from the study. CONCLUSION: ER felodipine 5 to 10 mg/day smoothly and safely reduces 24-hour ambulatory BP in elderly patients with hypertension.     

The importance of blood pressure variability in hypertension

Use of ambulatory blood pressure monitoring (ABPM) techniques has revealed that blood pressure is characterized by a considerable degree of variability over a 24 h period as a result, not only of the well-known fluctuations that occur between wakefulness and sleep, but also of the minute-to-minute changes induced by a variety of behavioural conditions. The degree of these variations is also influenced by neural mechanisms responsible for cardiovascular regulation, such as the arterial baroreflex. Blood pressure variability increases with age and blood pressure values, and its magnitude has been shown to correlate independently with the target-organ damage of hypertension. This has stimulated both the development of antihypertensive drugs able to reduce blood pressure homogeneously over 24 h, and recent proposals to develop more accurate indices, such as the smoothness index, to quantify the distribution of the antihypertensive effect over the entire day and night. Despite the important information that ABPM can provide concerning daily-life blood pressure variations and their modification by treatment, international guidelines suggest that it should not yet be used routinely in daily practice, but rather reserved for selected patients.