Vasopeptidase inhibition in heart failure.
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Biomedical subjects
Publications and source records attributed to W H van Gilst.
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This study describes the rationale, design, and baseline characteristics of a trial to determine whether treatment with fosinopril 20 mg/day and/or pravastatin 40 mg/ day will prevent cardiovascular and renal disease in nonhypertensive (RR <160/100 mm Hg and not using antihypertensive medication) and nonhypercholesterolemic (total cholesterol <8.0 or <5.0 mmol/L in case of previous myocardial infarction and not using lipid lowering medication) men and women with persistent microalbuminuria (urinary albumin excretion >10 mg/L once in an early morning spot urine and 15 to 300 mg/24-hour at least once in two 24-hour urine collections). The Prevention of REnal and Vascular ENdstage Disease Intervention Trial is a single-center, double-blind, randomized, placebo-controlled trial with a 2 x 2 factorial design. The 864 randomized subjects will be monitored for a minimum of 4 years and a maximum of 5 years. The primary efficacy parameter is defined as the combined incidence of all-cause mortality or hospital admission for documented (1) nonfatal myocardial infarction, (2) myocardial ischemia, (3) heart failure, (4) peripheral vascular disease, (5) cerebrovascular accident and/or (6) end-stage renal disease.
BACKGROUND: Diltiazem reduces non-fatal reinfarction and refractory ischaemia after non-Q-wave myocardial infarction, an acute coronary syndrome similar to the incomplete infarction that occurs after successful reperfusion. We postulated that this agent would reduce cardiac events in patients after acute myocardial infarction treated initially with thrombolytic agents-a clinical application previously unexplored with heart-rate-lowering calcium antagonists. METHODS: A prospective, randomised, double-blind, sequential trial was done in 874 patients with acute myocardial infarction, but without congestive heart failure, who first received thrombolytic agents. Patients received either 300 mg oral diltiazem once daily, or placebo, initiated within 36-96 h of infarct onset, and given for up to 6 months. The trial primary endpoint was the cumulative first event rate of cardiac death, non-fatal reinfarction, or refractory ischaemia. Additional prespecified endpoints included several composites of non-fatal cardiac events (non-fatal reinfarction combined with refractory ischaemia, all recurrent ischaemia, or the need for myocardial revascularisation). The diagnosis of ischaemia, whether refractory or recurrent, and the need for myocardial revascularisation, was always based on objective electrocardiographical evidence of ischaemia, either at rest or on exertion. RESULTS: For the trial primary endpoint, 131 events occurred in the 444 placebo patients and 97 events in the 430 diltiazem patients (hazard ratio 0.79; 95% CI, 0.61-1.02; p=0.07). For non-fatal cardiac events, diltiazem treatment was associated with a relative decrease (0.76; 0.58-1.00) in the combined event rate of non-fatal reinfarction and refractory ischaemia. There was a similar decrease in the composite non-fatal endpoints of non-fatal reinfarction combined with all recurrent ischaemia (0.80; 0.64-1.00) and non-fatal reinfarction combined with the need for myocardial revascularisation (0.67; 0.46-0.96). The need for myocardial revascularisation alone was significantly reduced by 42% (0.61; 0.39-0.96). No major safety issues were encountered. CONCLUSIONS: Diltiazem did not reduce the cumulative occurrence of cardiac death, non-fatal reinfarction, or refractory ischaemia during a 6-month follow-up, but did reduce all composite endpoints of non-fatal cardiac events, especially the need for myocardial revascularisation.
BACKGROUND: To date, the use of beta-blockers in treating patients with chronic heart failure gains support, this since several large clinical trials reported reduced mortality after chronic beta-blockade. Part of these beneficial effects may result from inhibition of deleterious neurohormone activation that accompanies progression of chronic heart failure. The present study evaluates whether this neurohormone inhibition is preserved after chronic beta-blockade. METHODS: In a retrospective analysis the neurohormonal profiles of patients with moderate to severe chronic heart failure were studied from three treatment subgroups: (1) Without beta-blockers or ACE-inhibitors (n=15), (2) without beta-blockers, with ACE-inhibitors (n=324), (3) with beta-blockers and ACE-inhibitors (n=31). Patients were on beta-blockers for an average period of 3.8 years. Plasma samples were obtained under controlled conditions. RESULTS: Despite uneven group sizes, the groups were well matched for clinical characteristics. Plasma renin levels were significantly lower in patients treated adjunctively with beta-blockers. Plasma aldosterone and endothelin-I levels also tended to be lower after chronic beta-blockade, however, this did not reach statistical significance. CONCLUSIONS: Chronic adjunctive beta-blocker treatment shows significantly lower plasma renin levels when compared to single ACE-inhibition. This persistent reduction of plasma neurohormone activation may concomitantly reduce the chance of neurohormones to escape from inhibition.
In the present study, predictors of complicated initiation of beta blockade in patients with idiopathic dilated cardiomyopathy was studied. We found that generally accepted measures of severity of heart failure are not predictable, whereas low systolic blood pressure (< or =120 mm Hg) was the strongest predictor for problematic (up)titration.
UNLABELLED: Beta-adrenoceptor density is altered in different cardiac diseases. In heart failure beta-adrenoceptor density is down regulated but in acute myocardial ischemia beta-adrenoceptor density is up regulated. In hearts with myocardial infarction total beta-adrenoceptor density is decreased shortly after myocardial infarction. AIMS AND METHODS: To investigate whether total beta-adrenoceptor number is altered in the chronic phase after myocardial infarction, and to identify the specificity of alteration, we studied male Wistar rats (n = 18) which underwent a ligation of the left coronary artery or a sham operation. Twelve weeks after coronary ligation, rats were sacrificed and hearts were excised, perfused to obtain blood-free myocardium and frozen in liquid nitrogen. Infarcted myocardium was identified visually and separated from non-infarcted myocardium. Total beta-adrenoceptor number was calculated in fmol (-)-[125I]iodocyanopindolol specifically bound/mg protein and the relative amount of beta1- and beta2-adrenoceptor density was measured by inhibition of (-)-[125I]iodocyanopindolol binding with CGP 20712 A. RESULTS: Total beta-adrenoceptor number in infarcted myocardium was significantly decreased (25.7+/-1.4 vs. 24.9+/-2.2 vs. 20.1+/-3.2 fmol/mg protein (P=0.03) resp. Sham vs. Non-infarcted vs. Infarcted myocardium), due to a decrease of only beta1-adrenoceptor density (14.7+/-0.61 vs. 12.7+/-1.09 vs. 4.84+/-0.96 fmol/mg protein (P=0.004) resp.), whereas the beta2-adrenoceptor density and the dissociation constant (Kd) were not significantly decreased. CONCLUSION: In the infarcted myocardium total beta-adrenoceptor density is decreased due to a decreased beta1-adrenoceptor density at 12 weeks after myocardial infarction.
It has been suggested that local activation of the renin-angiotensin system is involved in early stages of myocardial pathophysiology. To date, there is increasing evidence for interactions between the renin-angiotensin system and the sympathetic nervous system; consequently, local sympathetic activation may also be involved in this. Microdialysis has great potential in the direct investigation of neurohormonal interactions. Therefore, the present study employs microdialysis to study the local effects of exogenous angiotensin II on the interstitial norepinephrine concentration of the normally innervated left ventricle of the anaesthetised rat. The present study investigates the effect of increasing dosages of exogenous angiotensin II on local interstitial norepinephrine. Furthermore, a single dose of losartan was infused on top of the highest dose of angiotensin II, in order to study possible involvement of angiotensin II type 1 (AT1) receptors. Both infusion and sampling were carried out locally, via the microdialysis probes. Concomitantly, circulating norepinephrine levels, heart rate and respiratory rate were monitored to evaluate physiologic stability of the preparation throughout the experiment. Time controls consisted of rats that were perfused with only a Ringer's solution. Angiotensin II induced a dose dependent increase in norepinephrine that was significantly reduced by losartan. Norepinephrine levels in both plasma (infusion experiment and time controls) and the left ventricular wall (time controls) remained stable throughout the experiment, just as heart rate and respiratory rate did. This study for the first time employs microdialysis to demonstrate direct interaction between the sympathetic nervous system and the renin-angiotensin system in the rat left ventricle. The data strongly suggest that AT1 receptors are involved in this interaction, since selective AT1 receptor blockade with losartan significantly reduced the angiotensin II induced norepinephrine concentration.
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OBJECTIVES: We performed positron emission tomography (PET) to evaluate myocardial ischemia in patients with idiopathic dilated cardiomyopathy (IDC). BACKGROUND: Patients with IDC have anatomically normal coronary arteries, and it has been assumed that myocardial ischemia does not occur. METHODS: We studied 22 patients with IDC and 22 control subjects using PET with nitrogen-13 ammonia to measure myocardial blood flow (MBF) at rest and during dipyridamole-induced hyperemia. To investigate glucose metabolism, fluorine-18 deoxyglucose (18FDG) was used. For imaging of oxygen consumption, carbon-11 acetate clearance rate constants (k(mono)) were assessed at rest and during submaximal dobutamine infusion (20 microg/kg body weight per min). RESULTS: Global MBF reserve (dipyridamole-induced) was impaired in patients with IDC versus control subjects (1.7 +/- 0.21 vs. 2.7 +/- 0.10, p < 0.05). In patients with IDC, MBF reserve correlated with left ventricular (LV) systolic wall stress (r = -0.61, p = 0.01). Furthermore, in 16 of 22 patients with IDC (derived by dipyridamole perfusion) mismatch (decreased flow/increased 18FDG uptake) was observed in 17 +/- 8% of the myocardium. The extent of mismatch correlated with LV systolic wall stress (r = 0.64, p = 0.02). The MBF reserve was lower in the mismatch regions than in the normal regions (1.58 +/- 0.13 vs. 1.90 +/- 0.18, p < 0.05). During dobutamine infusion k(mono) was higher in the mismatch regions than in the normal regions (0.104 +/- 0.017 vs. 0.087 +/- 0.016 min(-1), p < 0.05). In the mismatch regions 18FDG uptake correlated negatively with rest k(mono) (r = -0.65, p < 0.05), suggesting a switch from aerobic to anaerobic metabolism. CONCLUSIONS: Patients with IDC have a decreased MBF reserve. In addition, low MBF reserve was paralleled by high LV systolic wall stress. These global observations were associated with substantial myocardial mismatch areas showing the lowest MBF reserves. In geographically identical regions an abnormal oxygen consumption pattern was seen together with a switch from aerobic to anaerobic metabolism. These data support the notion that regional myocardial ischemia plays a role in IDC.
BACKGROUND: The EUROHEART programme is a rolling programme of cardiovascular surveys among the member nations of the European Society of Cardiology (ESC). These surveys will provide information on the nature of cardiovascular disease and its management. This manuscript describes a survey into the nature and management of heart failure. AIMS: The EuroHeart Failure survey aims to describe the quality of hospital care, diagnostic and therapeutic, for patients with suspected or confirmed heart failure in ESC member countries. Patients will be interviewed subsequent to hospital discharge to assess their understanding of their condition, side effects from and their compliance with therapy and their satisfaction with the management for heart failure. The quality of management will be judged against the recommendations contained in the ESC guidelines on diagnosis and treatment of heart failure. Outcome will be further assessed by repeat interviews in 6-12 months time. A further survey of heart failure in 2001/2002 is also planned. METHODS: A prospective survey of all deaths and discharges from medical (cardiology, internal medicine and geriatric medicine) and cardiac surgical wards to identify patients with heart failure, suspected or confirmed. Approximately 70 hospital clusters, comprising two to six hospitals in each cluster, in 24 member countries of the ESC are conducting the study. At the time of writing, approximately 30000 deaths and discharges have been screened and approximately 4000 patients have been enrolled. CONCLUSIONS: The EuroHeart Survey will allow actual practice to be compared to ESC guidelines on the diagnosis and treatment of heart failure. The surveys and guidelines should prove mutually informative. The main EuroHeart Failure project will be completed by late 2000. However, new centres volunteering to participate in the study (contact corresponding author) may be accepted providing they have the necessary research personnel and provided funding can be agreed for statistical support and administration.
The QUO VADIS (the effects of QUinapril On Vascular Ace and Determinants of ISchemia) study was a randomized, double-blind, placebo-controlled trial designed to evaluate the effects of long-term angiotensin-converting enzyme (ACE) inhibition on angiotensin II formation in human vasculature. Patients (n = 187) scheduled for coronary artery bypass surgery used study medication 27 +/- 1 days before surgery. Segments of internal mammary arteries were exposed to increasing doses (0.1 nM-1 microM) of angiotensin I and II in organ baths. The rate of local angiotensin II formation is a function of the reciprocal of the difference between the pEC50's of the dose response curves to angiotensin I and II (-log/mol) and of the area between the curves (units). Quinapril (40 mg) and captopril (3 x 50 mg) similarly and significantly reduced mean blood pressure compared with placebo (p = 0.04). Difference between pEC50's was 0.90 +/- 0.08 in quinapril patients compared with 0.60 +/- 0.08 for placebo (p = 0.01); the area between curves was 91 +/- 8 for quinapril patients compared with 67 +/- 8 for placebo (p = 0.03). Angiotensin II formation was decreased to a lesser extent with captopril and was not statistically different from placebo (p = 0.3); the difference between pEC50's was 0.83 +/- 0.15; the area between curves was 84 +/- 12. This is the first randomized study to demonstrate that long-term oral treatment with an ACE inhibitor reduces vascular angiotensin II formation in humans.
We evaluated the role of SH-groups in improvement of endothelial dysfunction with ACE-inhibitors in experimental heart failure. To this end, we compared the vasoprotective effect of chronic treatment with zofenopril (plus SH-group) versus lisinopril (no SH-group), or N-acetylcysteine (only SH-group) in myocardial infarcted (MI) heart failure rats. After 11 weeks of treatment, aortas were obtained and studied as ring preparations for endothelium-dependent and -independent dilatation in continuous presence of indomethacin to avoid interference of vasoactive prostanoids, and the selective presence of the NOS-inhibitor L-NMMA to determine NO-contribution. Total dilatation after receptor-dependent stimulation with acetylcholine (ACh) was attenuated (-49%, P<0.05) in untreated MI (n=11), compared to control rats with no-MI (n=8). This was in part due to impaired NO-contribution in MI (-50%, P<0.05 versus no-MI). At the same time the capacity for generation of biologically active NO after receptor-independent stimulation with A23187 remained intact. Chronic treatment with n-acetylcysteine (n=8) selectively restored NO-contribution in total dilatation to ACh. In contrast, both ACE-inhibitors fully normalized total dilatation to ACh, including the part mediated by NO (no significant differences between zofenopril (n=10) and lisinopril (n=8)). Zofenopril, but not lisinopril, additionally potentiated the effect of endogenous NO after A23187-induced release from the endothelium (+100%) as well as that of exogenous NO provided by nitroglycerin (+22%) and sodium nitrite (+36%) (for all P<0.05 versus no-MI). We conclude that ACE-inhibition with a SH-group has a potential advantage in improvement of endothelial dysfunction through increased activity of NO after release from the endothelium into the vessel wall. Furthermore, this is the first study demonstrating the selective normalizing effect of N-actylcysteine on NO-contribution to ACh-induced dilatation in experimental heart failure.
AIM: To assess the value of microalbuminuria as an indicator of increased cardiovascular risk in a non-diabetic population. METHODS AND RESULTS: 7579 non-diabetic subjects were studied with ages ranging from 28 to 75 years selected from a population based cohort. Using computerized Minnesota coding, ischaemic electrocardiographic abnormalities were divided into three categories: infarct patterns, major ischaemia, and minor ischaemia. Urinary albumin excretion was measured as the mean of two 24-h urine collections. Cardiovascular risk indicators were defined as an age above 60 years, male sex, hypertension, hypercholesterolaemia, smoking, obesity and a positive cardiovascular family history. Microalbuminuria was associated with age, sex, blood pressure, serum cholesterol, serum glucose, body mass index and all three categories of electrocardiographic abnormalities. In a multivariate model, adjusted for established cardiovascular risk indicators, microalbuminuria was independently associated with infarct patterns (OR [95% CI] 1.61 [1.12-2.32]), major ischaemia (OR 1.43 [1.08-1.91]) and minor ischaemia (OR 1.32 [1.03-1.68]). CONCLUSIONS: The independent association between microalbuminuria and ischaemic electrocardiographic abnormalities suggests that microalbuminuria has additional value to conventional risk indicators in predicting cardiovascular disease in non-diabetics. Assessment of microalbuminuria could be an instrument to identify those at an increased risk for coronary vascular disease in an early stage.
Multiple indirect lines of evidence point at a cardioprotective role for enhanced bradykinin formation. In particular, the inhibition of angiotensin-converting enzyme, also known as kininase II, can protect against cardiac ischemia, putatively via accumulation of bradykinin. To address whether an increase in kinin formation is sufficient to protect against cardiac ischemia, we studied transgenic rats harboring the human tissue kallikrein gene TGR(hKLK1) under the control of the metallothionein promoter, which drives expression of the transgene in various organs including the heart. We subjected the isolated hearts from transgenic rats and their transgene negative littermates to ex vivo regional cardiac ischemia and reperfusion. During the experiment, the hearts were treated with either vehicle or the specific bradykinin type 2 receptor antagonist HOE 140 (10-9 M). In the transgenic rats, overflow of nucleotide breakdown products upon reperfusion was significantly less (455 +-54 nmol/min/g in transgene negative rats vs. 270+-57 nmol/min/g in the transgenic rats, P.
Dopaminergic agonists remain of interest in the treatment of heart failure; however, concomitant stimulation of alpha- and beta-receptors should be avoided. This study evaluates the dopaminergic and adrenergic (vasodilating) properties of Z1046, epinine (the active metabolite of ibopamine), and dopamine. Isotonic contraction experiments were performed on human internal mammary artery rings in vitro. alpha1-Antagonistic effects of Z1046 were demonstrated by performing cumulative dose-response curves with the selective alpha1-agonist phenylephrine in the presence of Z1046. Furthermore, both alpha1- and dopamine-mediated receptor effects of Z1046, epinine, and dopamine were studied by performing cumulative dose-response relations both at baseline and in precontracted artery rings both with and without the D1-like antagonist SCH23390. In contrast to both epinine and dopamine, Z1046 is devoid of alpha1-receptor-mediated contraction. Furthermore, Z1046, epinine, and dopamine induced direct dopamine receptor-mediated vasodilation when interfering alpha1 effects were blocked. In contrast to epinine and dopamine, Z1046 is devoid of vasoconstricting properties at higher dosages. Because of its D1-like agonistic and alpha1-antagonistic properties, Z1046 is an effective vasodilator in the whole dosage range. Because of its total receptor profile, Z1046 appears to be more favorable for treatment of heart failure than is ibopamine.
An adenine/cytosine (A/C) base substitution at position 1166 in the angiotensin II type 1 receptor (AT(1)R) gene is associated with the incidence of essential hypertension and increased coronary artery vasoconstriction. However, it is still unknown whether this polymorphism is associated with a difference in angiotensin II responsiveness. Therefore, we assessed whether the AT(1)R polymorphism is associated with different responses to angiotensin II in isolated human arteries. Furthermore, we evaluated whether inhibition of the renin-angiotensin system modifies the effect of the AT(1)R polymorphism. One hundred twelve patients who were undergoing coronary artery bypass graft surgery were prospectively randomized to receive an ACE inhibitor or a placebo for 1 week before surgery. Excess segments of the internal mammary artery were exposed to angiotensin II (0.1 nmol/L to 1 micromol/L) and KCl (60 mmol/L) in organ bath experiments. Patients homozygous for the C allele (n=17) had significantly greater angiotensin II responses (percentage of this maximal KCl-induced response) than did patients genotyped with AA+AC (n=95, P<0.05). Although ACE inhibition increased the response to angiotensin II, the difference in the response to angiotensin II, between CC and AA+AC patients remained intact in ACE inhibitor-treated patients. These results indicate increased responses to angiotensin II in patients with the CC genotype. The mechanism is preserved during ACE inhibition, which in itself also increased the response to angiotensin II. This reveals that the A1166C polymorphism may be in linkage disequilibrium with a functional mutation that alters angiotensin II responsiveness, which may explain the described relation between this polymorphism and cardiovascular abnormalities.
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The effect of beta blockade on heart rate in patients with either idiopathic or ischemic cardiomyopathy was studied. It was found that beta blockade reduced the early morning increase in heart rate to a greater extent in patients with idiopathic dilated cardiomyopathy than in those with ischemic dilated cardiomyopathy.