with consequent reduction in angiot

with consequent reduction in angiotensin II concentrations.A sympatholytic effect also occurs by blocking 2-receptor–mediated increases in norepinephrine release from sympathetic nerve terminals. These mechanisms of action have implications for the effectiveness of -blockers in AfricanAmericans and in the elderly. Because African Americanstend to have low-renin and salt-sensitive hypertension, it is not surprising that -blockers reduce blood pressure much less in this ethnic group than in Caucasian hypertensive patients.25 African Americans with heart failure, however, experience the same reduction in mortality and morbidity with-blockers as do Caucasian patients.26 The elderly tend not only to have a higher incidence of low-renin hypertension than younger individuals but also to exhibit blunted-receptor–mediated responses to -agonists.27 These differences may explain why the elderly derive less survival benefit from -blockersthan do their younger counterparts.28 A concern has been expressed in the literature about using-blockers in patients with cardiovascular disease who have concomitant reactive airway disease. -blockers, especially those with a high affinity for the 2 receptor, are relatively contraindicated in patients with asthma and chronic lung disease with a significant bronchospastic component. 29 The results of a recent meta-analysis of studies that have explored the use of cardioselective-blockers in these patients suggest that cardioselective -blockers not only are safe but actually may enhance sensitivity to inhaled -agonists because of receptor activation.30,31 Although-blockers have been used extensively in hypertension and related disorders for a number of years, a recent extensive re-analysis of various trials suggested that atenolol exerts no therapeutic benefits whatsoever.32 The investigators surveyed the major trials in hypertension that used atenolol and concluded that it was no better than a placebo and significantly inferior to other antihypertensive drugs. Whether these findings are applicable to other -blockers is unclear. Nevertheless, this provocative re-appraisal of atenolol casts doubt on the relative use of -blocker therapy in patients with hypertension. Much debate can be expected as a result of this observation from atenolol-based studies. Some credence to these observations is gained by the demonstration of reduced benefits from atenolol therapy compared with losartan in the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study.33 In this trial, losartan-based treatment compared with an atenolol-based regimen at equivalent blood pressure levels decreased the risk for fatal and nonfatal strokes in a high-risk population. Thus, one could argue for angiotensin-receptor blockade over -blockade for superior target organ protection in patients with hypertension, at least in those older patients with left ventricular hypertrophy.

ผลลัพธ์ (แอฟริกา) 1:

met gevolglike afname in angiotensien II concentrations.A simpatolitiese effek kom ook deur die sluit van 2-reseptor-gemedieerde stygings in norepinefrien vrylating uit die simpatiese senuwee terminale. Hierdie meganismes van aksie het implikasies vir die effektiwiteit van -blockers in AfricanAmericans en in die bejaardes. Omdat Afrika Americanstend lae-renien en sout sensitiewe hoë bloeddruk te hê, is dit nie verbasend dat -blockers verminder bloeddruk baie minder in hierdie etniese groep as in Ander hipertensiewe patients.25 Afro-Amerikaners met hartversaking, maar ervaar dieselfde vermindering in. sterftes en siektes met-blokkers as doen Blank patients.26 Die bejaardes is geneig om nie net 'n hoër voorkoms van lae-renien hipertensie as jonger individue te hê, maar ook afgestomp-reseptor-gemedieerde antwoorde om hierdie verskille te -agonists.27 kan verduidelik waarom uit te stal. bejaardes lei minder oorlewing voordeel t van -blockersthan hul jonger counterparts.28 A kommer is uitgespreek in die literatuur oor die gebruik van-blokkers in pasiënte met kardiovaskulêre siekte, wat gepaardgaande reaktiewe lugwegsiekte het. -blockers, veral dié met 'n hoë af oneindigheid vir die 2 reseptor, is relatief teenaangedui in pasiënte met asma en chroniese longsiekte met 'n beduidende brongospastiese komponent. 29 Die resultate van 'n onlangse meta-analise van die studie is dat die gebruik van cardioselective-blokkers in hierdie pasiënte ondersoek het daarop dui dat cardioselective -blockers nie net veilig is maar eintlik kan sensitiwiteit verbeter ingeasem -agonists gevolg van reseptor activation.30,31 Hoewel. -blockers is op groot skaal in hoë bloeddruk en verwante versteurings vir 'n aantal jare 'n onlangse uitgebreide re-ontleding van verskeie toetse het voorgestel dat atenolol oefen geen terapeutiese voordele whatsoever.32 Die ondersoekbeamptes van die groot toetse in hoë bloeddruk wat gebruik atenolol en die gevolgtrekking gekom dat die opname. dit was niks beter as 'n placebo en beduidend minderwaardig aan ander antihipertensiewe middels. Of hierdie bevindinge is van toepassing op ander -blockers is onduidelik. Nietemin, hierdie uitdagende re-evaluering van atenolol twyfel oor die relatiewe gebruik van -blocker terapie in pasiënte met hipertensie. Baie debat verwag kan word as 'n gevolg van hierdie waarneming van atenolol studies. Sommige geloofwaardigheid aan hierdie waarnemings word verkry deur die demonstrasie van verminderde voordele van atenolol terapie in vergelyking met losartaan in die Losartaan Intervensie vir eindpunt Vermindering in Hipertensie (LIFE) study.33 In hierdie verhoor, losartaan-gebaseerde behandeling in vergelyking met 'n atenolol-gebaseerde dieet op. ekwivalent bloeddruk vlakke verminder die risiko vir noodlottige en nonfatal beroertes in 'n hoë-risiko bevolking. Dus, kan 'n mens argumenteer vir angiotensien reseptor blokkade oor -blockade vir beter teikenorgaan beskerming in pasiënte met hoë bloeddruk, ten minste in die ouer pasiënte met linker ventrikulêre hipertrofie.