Characteristics Associated with Upper-Range Doses of Beta-Blockers and Angiotensin-Renin Inhibitors in Reduced Ejection Fraction

BACKGROUND

Heart failure (HF) patients with reduced ejection fraction (HFrEF) are frequently treated with sub-optimal doses of angiotensin converting enzyme-inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), and beta blockers (BBs).

OBJECTIVES

To determine factors associated with attaining upper-range doses in patients with HFrEF.

METHODS

We examined treatment in patients with left ventricular ejection fraction (LVEF) ≤ 40% in a community-based, dedicated heart-failure clinic. Upper-range doses were defined as ≥ 75% of target recommended doses by heart failure society guidelines.

RESULTS

The majority of the 215 patients were men (82%); median age at presentation 73 years (interquartile range [IQR] 65-78) and LVEF of 30% (IQR 25-35%). Following the up-titration program, 41% and 35% of patients achieved upper-range doses of ACE-Is/ARBs and BBs, respectively. Higher body mass index (BMI) was the only parameter found to be associated with achieving upper-range doses of ACE-I/ARBs (odds ratio [OR] 1.13, 95% confidence interval [95%CI] 1.05-1.22, P = 0.001). More patients achieved this target as BMI increased, with a sharp decline in the highest obesity category (BMI ≥ 40 m2/kg). Attaining upper-range doses of BBs was associated with pre-existing diabetes mellitus (DM) (OR 2.6, 95%CI 1.34-5.19, P = 0.005); women were associated with attaining lower BBs doses (OR 0.34, 95%CI 0.13-0.90, P = 0.031).

CONCLUSIONS

Achieving upper-range doses of ACE-Is/ARBs and BBs in HFrEF outpatients in a treatment up-titration program were associated with greater BMI and DM, respectively. These findings may serve as benchmarks for up-titration programs.

Comparison of 18-Month Outcomes of Ambulatory Patients With Reduced (≤40%) Left Ventricular Ejection Fraction Treated in a Community-Based, Dedicated Heart Failure Clinic Versus Treated Elsewhere

We sought to examine the management and outcomes of ambulatory patients with heart failure and reduced ejection fraction in a community-based, dedicated clinic. Patients with left ventricular ejection fraction (LVEF) ≤40% were actively solicited to attend a community-based, dedicated clinic. Eligible patients who chose to decline constituted our control group. Of 552 patients with LVEF ≤40% (median age 73 years and median LVEF 35%), 304 (55%) agreed to attend the clinic. Patients with worse New York Heart Association class were more likely to attend the clinic (odds ratio 2.07 [1.45, 2.95], p <0.001), whereas women were more likely to decline (odds ratio 0.63 [0.42, 0.93], p <0.022). During 18 months of follow-up, patients in the dedicated clinic significantly improved their functional capacity (56% New York Heart Association 3 to 4 at baseline vs 27% at follow-up, p <0.001) and LVEF (35% [interquartile range 25, 35] at baseline vs 35% (interquartile range 30, 40) at follow-up, p <0.001). In comparison with patients managed routinely, patients treated in a dedicated clinic achieved better guideline-recommended pharmacological treatment (65% vs 85% receiving β blockers, p <0.001, 65% vs 82% receiving renin-angiotensin inhibitors, p = 0.0006, 31% vs 45% receiving mineralocorticoid receptor antagonists, p <0.001). During follow-up, electrical device implantation was similar (6% vs 7% of dedicated-HF-clinic patients, p = 0.700). Furthermore, overall survival was better in patients treated in the clinic (log rank p = 0.0006), even after censoring the first 4 months to account for potential bias (log rank p = 0.0232). In conclusion, management in a community-based, dedicated clinic compared with routine management was associated with augmented guideline-recommended treatment and improved survival.

[Tachykinin receptor subtypes involved in endothelium-dependent and -independent responses in rabbit intrapulmonary arteries]

In the present study, it was demonstrated that SP, neurokinin A (NKA), neurokinin B (NKB), SP methyl ester (SPME), [Ala5, beta-Ala8]-alpha-neurokinin fragment 4-10 (AANF) at 10(-8) M all caused contraction in non-contracted endothelium-intact arteries. SP- and SPME-induced contraction were reduced by removal of endothelium. All the peptides with the exception of AANF induced transient relaxation in the precontracted arteries. The relaxation were attenuated by removal of endothelium. The potency orders for endothelium-dependent contraction (EDC), -dependent relaxation (EDR) and -independent contraction (EIC) were SP > SPME >> NKA [symbol: see text] NKB [symbol: see text] AANF, SP > SPME > NKA > NKB >> AANF and NKA > AANF > NKB >> SP [symbol: see text] SPME, respectively. SP-induced EDC and EDR were attenuated by an NK1 antagonist but not by an NK2 antagonist. The SP-induced EIC was reduced by an NK2 antagonist. SP-induced EDC was attenuated by aspirin, OKY-046, and S-1452. The EDR was attenuated by L-NAME and methylene blue. The EDC induced by SPME was non-competitively attenuated by CP-99994, an NK1 antagonist. EDR was competitively inhibited by CP-99994. In conclusion, SP and related peptides caused EDC via NK1 receptors and TXA2 production, EDR via NK1 receptors and NO release and EIC via NK2 receptors in rabbit intrapulmonary arteries.

Inhibitory effects of various spasmolytics on the vagal afferent gastric excitatory response in cats

The inhibitory effects of atropine, cimetropium, pirenzepine and N-butylscopolamine on the vagal afferent gastric excitatory response in cats under anesthesia with pentobarbital sodium and infusion of gallamine were examined. Electrical stimulation of vagal trunk in left side (10 Hz in frequency, 3 msec in duration, 15 V in intensity and for 10 sec) caused an initial gastric excitatory response during the period of stimulation followed by a late excitatory gastric response after stimulation in normal cats. The initial response was inhibited by atropine (100 microg/kg, i.v.) and hexamethonium (10 mg/kg, i.v.), while the late response was inhibited by atropine but not by hexamethonium (10 mg/kg, i.v.). In chronic supranodose vagotomized cats 11-15 days after the operation, stimulation of the vagal trunk caused a late gastric excitatory response after the stimulation period, which was inhibited by atropine (100 microg/kg, i.v.) but not by hexamethonium (10 mg/kg, i.v.). The two types of gastric responses in normal cats have been defined as follows: the initial gastric excitatory response (atropine- and hexamethonium- sensitive) is due to activation of vagal efferent fibers and the late gastric excitatory response (atropine-sensitive and hexamethonium-resistant) is due to activation of vagal afferent fibers. ED50 values of atropine, cimetropium, pirenzepine and N-butylscopolamine in inhibiting the vagal afferent gastric response were 7.2 microg/kg (n=4), 2.4 microg/kg (n=6), 82.6 microg/kg (n=3) and 93.0 microg/kg (n=4), respectively. The inhibitory effects of atropine and cimetropium on the vagal afferent gastric excitatory response (hexamethonium-resistant) were more potent than those of pirenzepine and N-butylscopolamine. These results suggested that the potent inhibitory effects of cimetropium and atropine on the vagal afferent gastric response may involve a potent spasmolytic effect.

Pharmacological nature of TP receptor mediated contraction in human intrapulmonary artery

The present experiments were undertaken to elucidate the pharmacological nature of thromboxane A2/prostaglandin H2 receptor (TP)-mediated contraction in human intrapulmonary arteries. 9,11-epithio-11, 12-methano-thromboxane A2 (STA2) and (15S)-hydroxy-9 alpha, 11 alpha-(epoxymethano) prosta-5Z, 13E-dienoic acid (U46619) (TXA2 agonists) caused contractions in a concentration-dependent manner with EC50 values of 1.4 x 10(-9) M and 3.1 x 10(-9) M, respectively. S-1452 and ONO-3708 (TP receptor antagonists) concentration-dependently attenuated the STA2 (10(-8) M)-induced contraction with IC50 values of 5.8 x 10(-9) M and 4.2 x 10(-8) M, respectively. U-73122 (3 x 10(-6) M) and 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (3 x 10(-5) M) (phospholipase C inhibitors) significantly attenuated the STA2-induced contraction. Ca(+2)-induced contraction in the presence of STA2 (10(-8) M) in Ca(+2)-free medium was attenuated by nifedipine (10(-6) M) by 40%. The remaining nifedipine-resistant Ca(+2)-induced contraction was not attenuated by nitroglycerin (10(-5) M), but forskolin (10(-5) M) (adenylate cyclase stimulant) significantly decreased it by 75%. The results clearly indicate that in human intrapulmonary artery, there are TP receptors coupled with phospholipase C activation and that TP receptor-mediated Ca(+2)-mobilization is in part nifedipine- and nitroglycerin-resistant, but forskolin-sensitive.

Possible involvement of endothelial leukotrienes in acetylcholine-induced contraction in rabbit coronary artery

In endothelium-intact preparations of rabbit coronary artery, acetylcholine (3 x 10(-8)-10(-6) M) caused a contraction in the presence of N omega-nitro-L-arginine methyl ester (10(-4) M). Removal of endothelium significantly attenuated the contraction. The present experiments were undertaken to elucidate whether the acetylcholine-induced contraction in endothelium-intact preparations was due to arachidonic acid metabolites, endothelin or superoxide. The acetylcholine-induced contraction in endothelium-intact preparations was attenuated by manoalide (10(-6) M and 3 x 10(-6) M) or oleyloxyethyl phosphorylcholine (10(-5) M) (phospholipase A2 inhibitors), BAY x 1005 (3 x 10(-6) and 10(-5) M) or L 663,536 (10(-6) and 10(-5) M) (leukotriene synthesis inhibitors) and ONO-1078 (10(-6) and 3 x 10(-6) M) or SK&F 104353 (10(-6) and 3 x 10(-6) M) (leukotriene antagonists). The contraction was not affected by aspirin (10(-4) M) or indomethacin (10(-6) M) (cyclooxygenase inhibitors), S-1452 (10(-8) M) or ONO-3708 (10(-7) M) (thromboxane A2 antagonists), FR139317 (10(-6) M) (endothelin receptor antagonist) or superoxide dismutase (150 u/ml) combined with catalase (1000 u/ml), or allopurinol (10(-5) M) (antioxidants). In contrast, the endothelium-independent contraction induced by acetylcholine was unaffected by any of these inhibitors and antagonists listed above. The present experiments demonstrate that in the presence of N omega-nitro-L-arginine methyl ester, acetylcholine partly causes an endothelium-dependent contraction in rabbit coronary artery which is probably due to leukotriene C4 and D4, but does not involve production of thromboxane A2, endothelin or superoxide.

Pharmacological natures of caffeine-induced endothelium-dependent and -independent contraction in canine mesenteric artery

The present experiments were carried out to elucidate whether pharmacological nature of caffeine (1 mM)-induced endothelium-dependent contraction (EDC) is different from that of caffeine (10 mM)-induced endothelium-independent contraction (EIC) in canine mesenteric artery. Caffeine (1 mM)-induced EDC was abolished when arterial strips were incubated in Ca(++)-free medium for 20 min, but EIC was not abolished. EGTA and EDTA (0.5 and 1 mM) attenuated the EDC, and at the concentration of 2.5 mM completely abolished the EDC. Nifedipine (10(-6) and 3 x 10(-6) M), diltiazem (10(-6) M) and verapamil (10(-6) M) did not affect the caffeine (1 mM)-induced EDC. Lemakalim (10(-8), 3 x 10(-8) and 10(-7) M) attenuated the caffeine (1 mM)-induced EDC in a concentration-dependent manner. Lemakalim (10(-7) M) nearly abolished the EDC. The inhibitory effect of lemakalim (10(-7) M) on the EDC was antagonized in the presence of glibenclamide (3 x 10(-6) M). In contrast, caffeine (10 mM)-induced EIC was resistant to lemakalim at higher concentration (3 x 10(-7) M). Forskolin (10(-7), 3 x 10(-7) and 10(-6) M) significantly attenuated both the caffeine (1 mM)-induced EDC and caffeine (10 mM)-induced EIC. The inhibitory effect of forskolin on the EDC was augmented in the presence of rolipram (10(-6) M). Nitroglycerin (10(-5) M) attenuated significantly caffeine-induced both EDC and EIC. The inhibitory effect of nitroglycerin on the EDC was augmented in the presence of zaprinast (10(-5) M). The present experiments demonstrate that caffeine-induced EDC is due to nifedipine-resistant and lemakalim-sensitive Ca++ mobilization and the EIC is due to both nifedipine- and lemakalim-resistant Ca++ mobilization in canine mesenteric artery.

An endothelium-dependent contraction in canine mesenteric artery caused by caffeine

1. We examined whether or not caffeine caused an endothelium-dependent contraction (EDC) in canine mesenteric artery and whether the endothelium-dependent contracting factors (EDCF) were arachidonic acid metabolites. 2. Caffeine (1, 3 and 10 mM) caused a transient contraction in endothelium-intact arterial strips. Removal of the endothelium significantly attenuated the caffeine (1 and 3 mM)-induced contraction. 3. Caffeine (1 mM)-induced EDC was not affected by quinacrine and manoalide (phospholipase A2 inhibitors), indomethacin and aspirin (cyclo-oxygenase inhibitors), ONO-3078 and S-1452 (thromboxane A2 antagonists) or AA-861 and TMK-777 (lipoxygenase inhibitors). 4. Caffeine (1 mM)-induced EDC was also unaffected by 50-235 (an endothelin A receptor antagonist). In addition, catalase combined treatment with superoxide dismutase, or allopurinol (antioxidant) did not affect the EDC. 5. Gro-PIP and NCDC (phospholipase C inhibitors) did not affect the caffeine-induced EDC. However, wortmannin (a phospholipase D inhibitor) and staurosporine (a protein kinase C inhibitor) attenuated the caffeine-induced EDC. 6. The present experiments demonstrate that caffeine causes an EDC in canine mesenteric artery and suggest that the EDCF mediating this response is probably not arachidonic acid metabolites, endothelin or superoxide. Instead, caffeine-induced EDC may be due to activation of the phospholipase D pathway.

Endothelium-dependent contraction produced by acetylcholine and relaxation produced by histamine in monkey basilar arteries

The present experiments were carried out to investigate endothelium-dependence of the responses to ACh, arachidonic acid and histamine in monkey basilar arteries. As we reported previously (1), ACh (10(-7) M) and arachidonic acid (5 x 10(-7) M) caused endothelium-dependent contraction (EDC) in both monkey and canine basilar arteries. The endothelium-derived contracting factor (EDCF) is probably TXA2, since the EDC was attenuated by a cyclooxygenase inhibitor (aspirin, 5 x 10(-5) M), thromboxane A2 (TXA2) synthetase inhibitors (OKY-046, 10(-5) M; RS-5186, 10(-6) M) and TXA2 antagonists (ONO-3708, 10(-8) M; S-145, 5 x 10(-9) M). Histamine caused endothelium-dependent relaxation (EDR) in monkey basilar arteries and EDC in canine basilar arteries. The EDR in monkey basilar arteries was attenuated by nitric oxide synthetase inhibitor, NG-monomethyl-L-arginine (L-NMMA) in a concentration-dependent manner and the EDC in canine basilar arteries was attenuated by aspirin, TAX2 synthetase inhibitors and TXA2 antagonists. The EDR and EDC were antagonized by tripelennamine (10(-6) M) but not by cimetidine (10(-5) M), indicating that they are mediated by H1-receptors. From these results, we suggest that in the monkey basilar artery, either there are two types of endothelium, an EDCF type for ACh and arachidonic acid and an EDRF type for histamine, or there is single type of endothelium with two types of signalling processes, one for EDC and one for EDR.

Endothelium-dependent contraction produced by acetylcholine and relaxation produced by histamine in monkey basilar arteries

The present experiments were carried out to investigate the endothelium dependence of the responses to acetylcholine (ACh), arachidonic acid, and histamine in monkey basilar arteries. ACh and arachidonic acid caused endothelium-dependent contraction (EC) in both monkey and canine basilar arteries. The endothelium-derived contracting factor (EDCF) was probably thromboxane A2 (TxA2), as the EDC was attenuated by a cyclooxygenase inhibitor, TxA2 synthetase inhibitors, and TxA2 antagonists. On the other hand, histamine caused endothelium-dependent relaxation (EDR) in monkey and EDC in canine basilar arteries. The EDR in monkey basilar arteries was attenuated by a nitric oxide synthase inhibitor. The EDR and EDC were antagonized by tripelennamine but not by cimetidine, indicating that they are mediated by H1-receptors. From these results, we suggest that in the monkey basilar artery, either there are two types of endothelium (an EDCF type for ACh and arachidonic acid and an EDRF type for histamine) or there is a single type of endothelium with two types of signalling processes (one for EDC and one for EDR).

Nifedipine-resistant Ca(++)-induced contraction in tail artery of spontaneously hypertensive rats

Nifedipine-resistant Ca(++)-induced contractions (NR-Ca(++)-contraction) were compared in the tail arteries from SHRs and WKYs (5 and 13 week old). NR-Ca(++)-contraction of tail artery was defined as follows: Ca(++)-induced contraction in the presence of norepinephrine (NE) (10(-5) M) or 5-hydroxytryptamine (5-HT) (10(-5) M) in Ca(++)-free medium containing EGTA (0.1 mM) and nifedipine (10(-6) M). NR-Ca(++)-contractions in arteries from 5 week old SHRs and WKYs were not different. In contrast, NR-Ca(++)-contractions in arteries from 13 week old SHRs were about 2-fold greater than in arteries from 13 week old WKYs. In arteries from 13 week old WKYs and SHRs, nitroglycerin (10(-5) M) significantly reduced the NR-Ca(++)-contraction in the presence of 5-HT but not in the presence of NE. The reduction was inhibited by the presence of methylene blue (3 x 10(-6) M). 8-Bromo-cGMP (10(-4) M) reduced significantly the NR-Ca(++)-contraction in the presence of 5-HT in arteries from 13 week old SHRs and WKYs. The present experiments clearly demonstrated that the NR-Ca(++)-contractions (both in the presence of NE and 5-HT) in 13 week old SHRs were significantly greater than those in arteries from 13 week old WKYs. These results suggest that in addition to an increase in voltage-operated Ca++ mobilization reported by others, an increase in NR-Ca++ mobilization may contribute to the development of hypertension in SHR.

Inhibitory effects of beta-alanine on the vagal efferent and afferent excitatory responses of the stomach to stimulation of vagal trunk in cats

The effects of beta-alanine on the electrically evoked vagal efferent (hexamethonium-sensitive initial excitatory response) and afferent (hexamethonium-resistant delayed excitatory response) responses of the cat stomach were studied. beta-alanine (30 to 300 micrograms/kg, i.v.) dose-dependently inhibited both the efferent and afferent response. The IC50 values of beta-alanine on the efferent and afferent response were 296 +/- 65 micrograms/kg and 128 +/- 35 microgram/kg, respectively. Maximal inhibitory effects of beta-alanine (300 micrograms/kg, i.v.) appeared about 1 hr after the injection. Glycine and taurine (100 to 10,000 micrograms/kg) did not affect these responses. Treatment with hexamethonium (10 mg/kg, i.v.) prevented the efferent response, but augmented the afferent response. The treatment with hexamethonium abolished the inhibitory effect of beta-alanine on the afferent response. Both picrotoxin (100 and 500 micrograms/kg, i.v.) and bicuculline (2000 micrograms/kg, i.v.) antagonized the inhibitory effects of beta-alanine on the vagal efferent and afferent responses of the stomach. The present experiments clearly demonstrated that beta-alanine inhibited both the vagal efferent and afferent excitatory responses of stomach to electrical stimulation of vagal trunk in cats.

Pharmacological characteristics of NP-252, a new dihydropyridine slow Ca2+ channel blocker, in isolated rabbit vascular smooth muscle and guinea pig myocardium: vascular selectivity

NP-252, a new dihydropyridine derivative, and nifedipine non-competitively inhibited contractile responses to KCl and responses to Ca2+ in Ca(2+)-free medium containing KCl in rabbit aorta and renal, mesenteric, coronary and basilar arteries, mesenteric veins and vena cava. The effects of NP-252 in these smaller arteries and veins were much greater than those in aorta. However, a similar differential selectivity was not seen with nifedipine. In aorta, only NP-252 reduced total La3+ resistant 45Ca binding. However, the increases in bound 45Ca at La3+ resistant sites and 45Ca unidirectional influx due to KCl were inhibited by both NP-252 and nifedipine. The displacement of [3H]nitrendipine binding to rabbit aorta was monophasic for both NP-252 and nifedipine. In guinea-pig papillary muscles, NP-252 (greater than 10(-7) M) slightly decreased action potential duration, developed tension and slow action potentials. The cardiac effects of NP-252 were much less prominent than those of nifedipine. These results indicate that NP-252 inhibits voltage-operated Ca2+ channels in small arteries and veins much more effectively than those in aorta, and this tissue selectivity is more apparent for NP-252 than nifedipine.

Effects of 15(R)-15-methyl prostaglandin E2 (arbaprostil) on gastric secretion and various gastric lesions induced in rats

We studied the effects of 15(R)-15-methyl prostaglandin E2 (arbaprostil) on gastric secretion and various acute and chronic gastric lesions produced in rats. Arbaprostil significantly inhibited gastric secretion in 4 hr-pylorus-ligated preparations when given intraduodenally in a dose of 30 or 100 micrograms/kg. The agent, however, significantly stimulated gastric secretion of rats with either a ligated or intact pylorus when given orally in doses of 3-100 micrograms/kg. Orally administered arbaprostil dose-dependently prevented the development of HCI-ethanol-, histamine-, water-immersion stress-, or indomethacin-induced gastric erosions. Intraduodenally administered arbaprostil also dose-dependently prevented the development of aspirin-induced gastric erosions in pylorus-ligated rats. Arbaprostil, given orally in doses of 1-100 micrograms/kg twice daily for 2 weeks, had little or no effect on the healing of acetic acid-induced gastric ulcers. However, oral administration of the agent in a dose of 3 or 10 micrograms/kg twice daily for 4 weeks significantly accelerated the healing of acetic acid-induced gastric ulcers. The increase in doses up to 100 micrograms/kg twice daily for 4 weeks had no effect on ulcer healing. These results indicate that arbaprostil, at either antisecretory or even acid stimulating doses, is effective in preventing the development of acute gastric erosions and in accelerating the healing of chronic gastric ulcers.