Effect of allopurinol on mortality and hospitalisations in chronic heart failure: a retrospective cohort study

OBJECTIVE

To examine whether allopurinol is associated with any alteration in mortality and hospitalisations in patients with chronic heart failure (CHF). This hypothesis is based on previous data that a high urate concentration is independently associated with mortality with a risk ratio of 4.23 in CHF.

DESIGN

Retrospective cohort study.

SETTING

Medicines Monitoring Unit, Ninewells Hospital, Dundee, UK.

PATIENTS

1760 CHF patients divided into four groups: those on no allopurinol, those on long term low dose allopurinol, those on short term low dose allopurinol, and those on long term high dose allopurinol.

MAIN OUTCOME MEASURES

Total mortality, cardiovascular mortality, cardiovascular hospitalisations, cardiovascular mortality or hospitalisations.

RESULTS

Long term low dose allopurinol was associated with a significant worsening in mortality over those who never received allopurinol (relative risk 2.04, 95% confidence interval (CI) 1.48 to 2.81). This may be because low dose allopurinol is insufficient to negate the adverse effect of a high urate concentration. However, long term high dose (> or = 300 mg/day) allopurinol was associated with a significantly better mortality than longstanding low dose allopurinol (relative risk 0.59, 95% CI 0.37 to 0.95). This may mean that high dose allopurinol can fully negate the adverse effect of urate and return the mortality to normal.

CONCLUSIONS

Long term high dose allopurinol may be associated with a better mortality than long term low dose allopurinol in patients with CHF because of a dose related beneficial effect of allopurinol against the well described adverse effect of urate. Further work is required to substantiate or refute this finding.

The prevalence of treatable left ventricular systolic dysfunction in patients who present with noncardiac vascular episodes: a case-control study

OBJECTIVES

We sought to determine the prevalence of treatable left ventricular (LV) systolic dysfunction (LVSD) in patients who present with their first noncardiac vascular episode.

BACKGROUND

Screening for LV dysfunction in patients who present with their first stroke (cerebrovascular accident), their first transient ischemic attack (TIA) or their first manifestation of peripheral vascular disease (PVD) may represent a golden opportunity to identify treatable LV dysfunction, and so their known high incidence of sudden cardiac death may be reduced.

METHODS

Participating in this study were 522 (75%) of 700 consecutive patients (302 patients with stroke, TIA or PVD and 220 age- and gender-matched control subjects). Each underwent a full clinical assessment, 12-lead electrocardiography and two-dimensional echocardiography. Left ventricular dysfunction was defined as LV ejection fraction < or = 40%.

RESULTS

Seventy-two (28%) patients with vascular disease and 11 (5.5%) control subjects were found to have LVSD. Twenty-six (28%) stroke patients, 22 (26%) patients with TIA and 24 (31%) patients with PVD had LVSD. Left ventricular systolic dysfunction was symptomatic in 44% of patients and in 35% of control subjects.

CONCLUSIONS

Left ventricular systolic dysfunction is five times more common among patients with stroke, TIA and PVD than among age- and gender-matched control subjects. Asymptomatic LVSD is more common than symptomatic LVSD in these patients. These findings suggest that routine screening of all patients with noncardiac vascular episodes for LVSD should now be considered. Future studies should investigate whether identifying and treating LVSD in these patients would reduce their known high rate of cardiac death.

Impact of aldosterone on vascular pathophysiology

The fact that spironolactone reduces deaths in cardiac failure suggests that aldosterone promotes cardiac death in heart failure, which begs the question: What are the mechanisms whereby it does this? The mechanisms whereby aldosterone promotes cardiac death are likely to be a combination of its production of endothelial dysfunction, myocardial fibrosis, and autonomic imbalance. It is quite possible that all three of these mechanisms actually stem from aldosterone's adverse effects on the endothelium. The term "aldosterone vasculopathy" has been coined to describe that the fundamentally adverse effect of aldosterone may well be on endothelial nitric oxide.

Heart failure in frail elderly patients: diagnostic difficulties, co-morbidities, polypharmacy and treatment dilemmas

BACKGROUND

Heart failure (HF) is difficult to diagnose and treat in older patients. Symptoms may be non-specific and the presence of co-morbidities and polypharmacy complicate treatment strategies. There are, however, few data to quantify the extent of these problems in the very elderly.

METHODS

A retrospective study of 116 patients (median age 86; range 65-98) with an established diagnosis of HF during their hospital admission.

MAIN OUTCOME MEASURES

the accuracy of diagnosis of heart failure according to the European Society of Cardiology (ESC) definition. The aetiology and frequency of associated co-morbidities and the nature of drug treatment.

RESULTS

The specificities of clinical signs, chest X-rays and abnormal ECGs for heart failure (ESC definition) were 50%, 20% and 9%, respectively. Only 28% of patients were admitted for worsening symptoms which could be attributed to HF. None of the patients had HF as their only medical problem. Co-morbidities included chest disease (30%), incontinence (29%), cerebrovascular disease (26%), musculoskeletal problems (41%). Barthel (activities of daily living) score was < or = 16/20 in 35%. Mental state questionnaire (MSQ) score was < or =7/10 in 38%. Ninety percent were taking four or more different medications. Thirty-nine percent were on psychotropic drugs. On discharge, a total of 88% of patients returned home to live independently and 35% were monitored by regular day hospital attendance.

CONCLUSION

Heart failure in frail elderly patients is often compounded by other major illnesses and polypharmacy which have a profound impact on their functional status. This has implications for the most effective targeting of evidence based treatment.

The neurohormonal natural history of essential hypertension: towards primary or tertiary aldosteronism?

Use of the aldosterone-to-renin ratio has controversially suggested that approximately 10% of hypertensives have primary aldosteronism, and most of these individuals are thought to have idiopathic hyperaldosteronism. The usual renin-angiotensin system control is intact in these individuals and is similar to that in low renin and essential hypertensives, differing only in the degree of sensitivity. There is recent evidence suggesting that hyperaldosteronism relates to aldosterone synthase genetic polymorphism, and also that increased angiotensin II stimulation of the adrenal glands appears to paradoxically upregulate the receptors increasing angiotensin II sensitivity. Taken together, the possibility arises that, in susceptible hypertensives, hyperaldosteronism could be acquired. Indeed, it is well known that renin-driven renovascular hypertension is associated with the development of hyperaldosteronism. Hypothetically, within the wider hypertensive population, these findings set the scene that angiotensin II adrenal sensitivity increases over time until the secretion of aldosterone becomes "autonomous" and hence "tertiary" aldosteronism in a significant proportion of hypertensives.

Cigarette smoking in men and vascular responsiveness

AIMS

Smoking is a major risk factor for developing atherosclerosis. In order to understand the vascular abnormalities observed in smokers, we investigated vascular responsiveness in cigarette smokers.

METHODS

We performed two consecutive matched group comparative studies to investigate vascular responsiveness using venous occlusion plethysmography. The mean effects of three incremental doses of each vasoactive agent are presented. Both studies compared smokers with nonsmokers.

RESULTS

The first investigated 68 subjects (smokers = 29; mean +/- s.d. ages; 24 +/- 6 vs 25 +/- 5 years; P = NS) and found smoking was associated with a significant blunting of the flow ratio between treated and untreated arms to endothelium-dependent vasodilatation to acetylcholine (mean +/- s.d., nonsmokers vs smokers) 4.07 +/- 2.18 vs 3.42 +/- 1.79 (P = 0.04, 95% CI 0.02, 1.12). By contrast, there was no significant difference in the responses to the endothelium-independent vasodilators sodium nitroprusside and verapamil. Smoking was also associated with a significant impairment in endothelium-dependent vasoconstriction induced by monomethyl-L-arginine (L-NMMA) 0.78 +/- 0.22 vs 0.87 +/- 0.21 (P = 0.006, 95% CI -0.14, -0.02) and a trend to blunted endothelium-independent vasoconstrictor responses to noradrenaline. In the second study we investigated the response to angiotensin I and II in 23 subjects (smokers = 12; mean +/- s.d. ages; 34 +/- 10 vs 32 +/- 11 years). There was significant impairment in smokers of the mean vasoconstrictor response to angiotensin I 0.51 +/- 0.15 vs 0.59 +/- 0.16 (nonsmokers vs smokers; P = 0.003, 95% CI -0.13, -0.03) and a nonsignificant trend towards impairment of the response to angiotensin II.

CONCLUSIONS

Cigarette smoking in male volunteers is associated with blunted basal and stimulated nitric oxide bioactivity. Endothelial independent vasodilator responses (to nitroprusside and verapamil) were unaltered in smokers. A defect in the vasoconstrictor response to angiotensin I was also seen.

Lisinopril improves endothelial function in chronic cigarette smokers

Cigarette smoking is a pernicious risk factor for the pathogenesis of coronary artery disease, and endothelial dysfunction is an important antecedent event in this process. This is important, as cigarette smoke is directly toxic to endothelial cells. Inhibitors of angiotensin-converting enzyme (ACE) have been shown to improve endothelial function in diabetes and hypercholesterolaemia, and are a promising option in smokers. We treated 23 subjects (age 38+/-12 years; mean+/-S.D.) for 8 weeks with 20 mg of lisinopril in a randomized controlled trial. Endothelial function was assessed by measurement of forearm blood flow responses to intra-arterial infusions of endothelial-dependent and -independent vasodilators and an endothelial-dependent vasoconstrictor [acetylcholine, sodium nitroprusside and monomethyl-L-arginine (L-NMMA) respectively] using venous occlusion plethysmography. Lisinopril significantly increased the forearm blood flow response to acetylcholine by 20% [lisinopril, 3.12+/-0.37 (mean+/-S.E.M.); placebo, 2.58+/-0.25; P=0.02, 95% confidence intervals (CI) 0.09, 1.06] (values given are ratios of flow in the infused arm to that in the control arm); there was no effect on the response to sodium nitroprusside (lisinopril, 3.97+/-0.40; placebo, 3.92+/-0.39; P=0.84; 95% CI -0.50, 0.61). The vasoconstrictor response to L-NMMA demonstrated a significant improvement (lisinopril, 0.77+/-0.06; placebo, 0.95+/-0.05; P<0.001; 95% CI -0.09, -0.27). In conclusion, these results indicate that ACE inhibition can improve endothelial function in cigarette smokers. We show that lisinopril improves both receptor-mediated and tonic NO release. The mechanism could be either that lisinopril limits the angiotensin II-induced production of superoxide radicals which would normally inactivate NO, or that lisinopril may increase bradykinin-mediated NO release.

Circadian variation in the effects of aldosterone blockade on heart rate variability and QT dispersion in congestive heart failure

OBJECTIVES

The study was designed to comprehensively evaluate the circadian effects of aldosterone blockade on autonomic tone and QT dispersion in chronic heart failure (CHF).

BACKGROUND

Spironolactone therapy given in addition to angiotensin-converting enzyme inhibitors improved survival in CHF, but the mechanism of its benefit is uncertain. Experimental evidence suggests that aldosterone may have detrimental effects on the autonomic nervous system, especially during the morning hours.

METHODS

Twenty-eight patients with New York Heart Association class II to IV CHF received spironolactone 50 mg daily and placebo for four weeks each in a double-blind crossover fashion. After each treatment phase, a full circadian assessment was undertaken of spironolactone's autonomic effects. The assessment included monitoring heart rate, QT dispersion, continuous Holter recordings, heart rate variability (HRV) and norepinephrine kinetics.

RESULTS

Spironolactone significantly reduced all indices of QT dispersion. The reductions in QTcmax, QTd and QTcd were greatest at 6 AM. In addition, spironolactone had favorable autonomic effects, which were limited to the morning (6-10 AM), including heart rate reduction and an improvement in HRV.

CONCLUSIONS

Spironolactone reduced heart rate and improved HRV and QT dispersion in CHF. Its effects were particularly prominent during the morning hours.

A placebo-controlled study examining the effect of allopurinol on heart rate variability and dysrhythmia counts in chronic heart failure

AIMS

Allopurinol improves endothelial function in chronic heart failure by reducing oxidative stress. We wished to explore if such an effect would attenuate autonomic dysfunction in CHF in line with many other effective therapies in CHF.

METHODS

We performed a prospective, randomized, double-blind cross-over study in 16 patients with NYHA Class II-IV chronic heart failure (mean age 67 +/- 10 years, 13 male, comparing allopurinol (2 months) at a daily dose of 300 mg (if creatinine < 150 micromol l-1) or 100 mg (if creatinine > 150 micromol l-1) with matched placebo. Mean heart rate and dysrhythmia counts were recorded from 24 h Holter tapes at monthly intervals for 6 months. We assessed autonomic function using standard time domain heart rate variability parameters (HRV): SDNN, SDANN, SDNN index, rMSSD and TI.

RESULTS

Allopurinol had no significant effect on heart rate variability compared with placebo; the results are expressed as a difference in means +/- s.d. with 95% confidence interval (CI) between allopurinol and placebo: SDNN mean = 6.5 +/- 4.8 ms, P = 0.18 and 95% CI (-3.7, 17); TI mean = -2.1 +/- 1.4, P = 0.16 and 95% CI (-5.2, 0.8); SDANN mean = -2.8 +/- 7 ms, P = 0.68 and 95% CI (-18, 12); SDNNi mean = 2 +/- 6.6, P = 0.7 and 95% CI (-12, 16); RMSSD mean = -0.9 +/- 2, P = 0.68 and 95% CI (-5.6, 3.7). For mean heart rate the corresponding results were 0.9 +/- 1.4, P = 0.5 and 95% CI (-2, 3.8). Log 24 h ventricular ectopic counts (VEC) were 0.032 +/- 0.37, P = 0.7 and 95% CI (-0.1, 0.2). Patient compliance with study medication was good since allopurinol showed its expected effect of reducing plasma uric acid (P < 0.001).

CONCLUSIONS

Allopurinol at doses, which are known to reduce oxidative stress appear to have no significant effect on resting autonomic tone, as indicated by time domain heart rate variability or on dysrhythmia count in stable heart failure patients.

Exercise blood pressure correlates with the maximum heart rate corrected QT interval in hypertension

Submaximal exercise systolic blood pressure (ExSBP) is a recognised predictor of cardiac mortality. This study examined the possibility that this might be related to increased QT dispersion or prolonged maximum QT(c) interval (QTcmax). Twenty-nine untreated hypertensive subjects were assessed. Each subject underwent an echocardiographic examination and a 24-h ambulatory blood pressure (ABP). ExSBP was measured during a 3-min lightweight submaximal Dundee step test. In multiple regressional analyses, only left ventricular mass index significantly predicted QT dispersion (R2 = 22.4%, P = 0.018) and QT(c) dispersion (R(2) = 25.3%, P = 0.012). However, with respect to QTcmax, ExSBP (R2 = 21.6%, P = 0.02) emerged as the sole significant predictor of this index. Five (17.2%) out of the 29 subjects had prolonged QTcmax > or = 430 ms and these subjects were not differentiated by 24-h ABP (146 (s.d. 21)/83 (16) vs 140 (14)/88 (11) mm Hg, P = Ns) but by ExSBP (226 (15) vs 188 (24) mm Hg, P = 0.002). In conclusion, systolic blood pressure measured during exercise correlated with QT(c) max in hypertension. This finding may partly explain the prognostic value of exercise blood pressure.

Adverse cardiac effects of salt with fludrocortisone in hypertension

The effect of salt on blood pressure (BP) is controversial. A more important question is whether salt can produce cardiac target-organ damage, irrespective of its effect on BP. We assessed the effect of salt with fludrocortisone on QT dispersion and echocardiographic left ventricular diastolic function in a prospective interventional study involving 29 hypertensive subjects with a raised aldosterone/renin ratio who were hospitalized for investigation of possible primary aldosteronism. Each subject over 4 days was given a total of 28.8 g (480 mmol) of sodium chloride and 1.5 mg of fludrocortisone with potassium supplementation. Baseline and posttreatment 12-lead ECGs and echocardiograms were obtained. There were no significant changes in body weight, pulse rate, or BP after treatment with salt and fludrocortisone. Plasma sodium was significantly increased from 141.4 (SD 2.1) to 142.6 (SD 2.4) mmol/L (P:=0.001). QT and QTc dispersion both significantly increased: +19.6 (SD 16.5) ms (95% CI, 13.4 to 25.9) (P:<0.001) and +19.8 (SD 20.9) ms (95% CI, 11.8 to 27.7) (P:<0.001), respectively. There were no significant changes in (n=15) left ventricular dimensions or systolic function, but all diastolic filling indexes, including the preload-independent index, flow propagation velocity (55.49 [SD 10.91] to 48.96 [SD 11.40] cm/s, P:=0.018) worsened, suggesting significant deterioration of left ventricular diastolic function with salt and fludrocortisone. In conclusion, a combination of salt with fludrocortisone increased QT dispersion and impaired left ventricular diastolic relaxation in hypertensive patients with high aldosterone/renin ratios. This raises the possibility that salt may have BP-independent adverse cardiac effects in susceptible hypertensive subjects.

Careful screening to target interventions to prevent sudden cardiac death

1. Cardiac death is due not only to coronary artery disease, but also to left ventricular (LV) abnormalities (fibrosis, dysfunction) and arrhythmogenic triggers, such as autonomic imbalance. 2. Nitric oxide deficiency could be a key mediator leading not only to coronary atherosclerosis, but also to LV abnormalities and autonomic imbalance. 3. It may be possible to screen for the above abnormalities (e.g. echocardiography and brain natriuretic peptide levels for LV abnormalities, 24 h tapes for autonomic imbalance and QT interval analysis). 4. Once individuals are identified as being at high risk, a range of interventions is possible (e.g. intensive statin therapy or angiotensin-converting enzyme inhibitors if LV abnormalities or autonomic imbalance are found).

Differential expression and synthesis of natriuretic peptides determines natriuretic peptide receptor expression in primary cultures of human proximal tubular cells

INTRODUCTION

The natriuretic peptides and natriuretic peptide receptors may play a beneficial role in hypertension and heart failure and possibly in opposing associated detrimental cellular changes in the heart, vasculature and kidney. These responses may be, in part, modulated by the natriuretic peptide clearance receptor rather than the natriuretic peptide receptors (NPR-A or NPR-B).

OBJECTIVE

To investigate the expression of the natriuretic peptide receptors (NPR-A,-B,-C) and the natriuretic peptides (ANP, BNP, CNP) in primary cultures of human proximal tubular cells and the role played by endogenously released natriuretic peptides in natriuretic peptide receptor expression.

RESULTS

Northern analysis demonstrated that freshly isolated human proximal tubular cells express the NPR-C only. However, at confluence mRNA transcripts for both the NPR-A and -B were expressed, accompanied by a significant cyclic guanosine monophosphate (cGMP) response to ANP and CNP, indicating the development of functionally active receptors. A significant increase in immunoreactive ANP, BNP and CNP in the cell supernatant accompanied the appearance of these receptors. Incubation of freshly isolated cells with exogenous ANP, BNP, CNP or with the NPR-C specific ligand C(4.23)ANF induced similar changes in receptor expression, suggesting that these changes were mediated via the NPR-C rather than the NPR-A or -B.

CONCLUSIONS

Significant changes in peptide and receptor expression occur during cell culture and may be integrally linked, with functionally active NPR-A and -B occurring in response to an increase in the expression of the natriuretic peptides possibly acting at the NPR-C.

Nonadherence with ACE inhibitors is common and can be detected in clinical practice by routine serum ACE activity

Our objective was to assess whether serum angiotensin-converting enzyme (ACE) activity during routine clinical practice accurately reflects patient adherence to ACE inhibitor treatment in chronic heart failure (CHF). During 1994-95, ACE was measured in 73 CHF patients who were routinely attending the heart failure clinic at Ninewells Hospital. At the same time, the Medicines Monitoring Unit collected data on whether and when prescriptions for ACE inhibitors were redeemed at community pharmacies, which enabled each patient's adherence over a prolonged period to be assessed. We then correlated whether an elevation in serum ACE was associated with poor adherence with ACE inhibitor treatment. In total, 18% of CHF patients appeared to exhibit less than 70% adherence with their ACE inhibitor treatment, with 34% exhibiting less than 85%adherence and 58% exhibiting less than 100% adherence. A serum ACE activity of more than 12 U/L gave 91% positive predictive accuracy that the patient was less than 100% adherent with his or her ACE inhibitor treatment. At the other extreme, a serum ACE less than 6.5 U/L gave 81% positive predictive accuracy that the patient was more than 85% adherent with ACE inhibitor treatment. Nonadherence with ACE inhibitor treatment, therefore, was found to be common in patients with CHF. The simple, inexpensive test of serum ACE activity can be used in CHF patients to identify many, although not all, nonadherent patients so that adherence-enhancing strategies can be targeted toward them. Further work is clearly required to explore the precise clinical utility of this promising test. (c)2001 by CHF, Inc.