PubMed · 672725
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M S Bickle. 1978-04-08. Blood pressure testing pilot study: evaluation.. https://doi.org/10.5694/j.1326-5377.1978.tb107923.x
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A simple, rapid method for the simultaneous determination of cardiovascular drugs: celiprolol, bisoprolol and irbesartan in human plasma is described. The two main features of the proposed method deal first, with a simultaneous solid phase extraction of weakly basic beta-blockers derivatives and irbesartan which exhibit weak acidic properties; second with an absorbance monitoring using diode array detection in order to insure an improved selectivity. The separation is performed on a C(18) Kromasil 4.6 mm x 150 mm column using a linear gradient to achieve an entire separation of the four species in less than 20 min. The full analytical validation is performed according to guidance for industry for bioanalytical method validation. Linearity of the response was demonstrated for each drug for a range fulfilling the reported plasma levels, that is 10-500, 5-250 and 20-1000 ng l(-1) for celiprolol, bisoprolol and irbesartan respectively. Intra- and inter-day relative standard deviations for all compounds were, in any case, lower than 11% and the method exhibits a convenient accuracy (percentage of relative error lower than 6% for each drug). In each case, the LOD were sufficient to detect post dose trough concentrations for checking patient's observance. Moreover, selectivity towards either endogenous species or co-administered drugs was demonstrated by combination of the use of the solid phase extraction process, gradient elution and diode array detection facilities, making thus, the proposed technique especially suitable for routine drug monitoring of resistant hypertensive patients.
CONTEXT: Self-measurement of blood pressure is increasingly used in clinical practice, but how it affects the treatment of hypertension requires further study. OBJECTIVE: To compare use of blood pressure (BP) measurements taken in physicians' offices and at home in the treatment of patients with hypertension. DESIGN, SETTING, AND PARTICIPANTS: Blinded randomized controlled trial conducted from March 1997 to April 2002 at 56 primary care practices and 3 hospital-based outpatient clinics in Belgium and 1 specialized hypertension clinic in Dublin, Ireland. Four hundred participants with a diastolic BP (DBP) of 95 mm Hg or more as measured at physicians' offices were enrolled and followed up for 1 year. INTERVENTIONS: Antihypertensive drug treatment was adjusted in a stepwise fashion based on either the self-measured DBP at home (average of 6 measurements per day during 1 week; n = 203) or the average of 3 sitting DBP readings at the physician's office (n = 197). If the DBP guiding treatment was above (>89 mm Hg), at (80-89 mm Hg), or below (<80 mm Hg) target, a physician blinded to randomization intensified antihypertensive treatment, left it unchanged, or reduced it, respectively. MEAN OUTCOME MEASURES: Office and home BP levels, 24-hour ambulatory BP, intensity of drug treatment, electrocardiographic and echocardiographic left ventricular mass, symptoms reported by questionnaire, and costs of treatment. RESULTS: At the end of the study (median follow-up, 350 days; interquartile range, 326-409 days), more home BP than office BP patients had stopped antihypertensive drug treatment (25.6% vs 11.3%; P<.001) with no significant difference in the proportions of patients progressing to multiple-drug treatment (38.7% vs 45.1%; P =.14). The final office, home, and 24-hour ambulatory BP measurements were higher (P<.001) in the home BP group than in the office BP group. The mean baseline-adjusted systolic/diastolic differences between the home and office BP groups averaged 6.8/3.5 mm Hg, 4.9/2.9 mm Hg, and 4.9/2.9 mm Hg, respectively. Left ventricular mass and reported symptoms were similar in the 2 groups. Costs per 100 patients followed up for 1 month were only slightly lower in the home BP group (3875 vs 3522 [4921 dollars vs 4473 dollars]; P =.04). CONCLUSIONS: Adjustment of antihypertensive treatment based on home BP instead of office BP led to less intensive drug treatment and marginally lower costs but also to less BP control, with no differences in general well-being or left ventricular mass. Self-measurement allowed identification of patients with white-coat hypertension. Our findings support a stepwise strategy for the evaluation of BP in which self-measurement and ambulatory monitoring are complementary to conventional office measurement and highlight the need for prospective outcome studies to establish the normal range of home-measured BP.
BACKGROUND: Endothelin (ET) is implicated in the pathophysiology of chronic renal failure (CRF). We therefore studied the systemic and renal hemodynamic effects of ET receptor antagonists in CRF and examined differences between selective ETA, selective ETB, and combined ETA/B receptor blockade. METHODS AND RESULTS: We conducted a randomized, placebo-controlled, double-blind, 4-way crossover study comparing selective ET receptor antagonists BQ-123 (ETA) and BQ-788 (ETB), given alone and in combination, in acute studies in 8 hypertensive CRF patients and 8 matched healthy controls. BQ-123, alone and in combination with BQ-788, reduced blood pressure in CRF, particularly with BQ-123 alone (mean arterial pressure: controls -4+/-2%, CRF -13+/-2%, P<0.01 versus placebo). In CRF, in the face of this fall in blood pressure, BQ-123 substantially increased renal blood flow (38.8+/-23.9%, P<0.01 versus placebo) and reduced renal vascular resistance (-44.5+/-11.3%, P<0.01 versus placebo) when given alone but not when combined with BQ-788. These changes were accompanied by a reduction in effective filtration fraction. BQ-123, alone or in combination with BQ-788, had minimal effects on the renal circulation in healthy controls, and BQ-788 alone produced both systemic and renal vasoconstriction in CRF and healthy controls. CONCLUSIONS: ETA receptor antagonism was highly effective in lowering blood pressure in CRF patients currently treated for hypertension. In addition, there were effects consistent with a renoprotective action. However, because the ETB receptor appears to play a key role in the maintenance of tonic renal vasodilation, combined ETA/B receptor antagonism, although it lowered blood pressure, did not confer these renal benefits.