Prolongation of atrio-ventricular node conduction in a rabbit model of ischaemic cardiomyopathy: Role of fibrosis and connexin remodelling.

Conduction abnormalities are frequently associated with cardiac disease, though the mechanisms underlying the commonly associated increases in PQ interval are not known. This study uses a chronic left ventricular (LV) apex myocardial infarction (MI) model in the rabbit to create significant left ventricular dysfunction (LVD) 8weeks post-MI. In vivo studies established that the PQ interval increases by approximately 7ms (10%) with no significant change in average heart rate. Optical mapping of isolated Langendorff perfused rabbit hearts recapitulated this result: time to earliest activation of the LV was increased by 14ms (16%) in the LVD group. Intra-atrial and LV transmural conduction times were not altered in the LVD group. Isolated AVN preparations from the LVD group demonstrated a significantly longer conduction time (by approximately 20ms) between atrial and His electrograms than sham controls across a range of pacing cycle lengths. This difference was accompanied by increased effective refractory period and Wenckebach cycle length, suggesting significantly altered AVN electrophysiology post-MI. The AVN origin of abnormality was further highlighted by optical mapping of the isolated AVN. Immunohistochemistry of AVN preparations revealed increased fibrosis and gap junction protein (connexin43 and 40) remodelling in the AVN of LVD animals compared to sham. A significant increase in myocyte-non-myocyte connexin co-localization was also observed after LVD. These changes may increase the electrotonic load experienced by AVN muscle cells and contribute to slowed conduction velocity within the AVN.

Long-term impact on healthcare resource utilization of statin treatment, and its cost effectiveness in the primary prevention of cardiovascular disease: a record linkage study.

AIMS: To assess the impact on healthcare resource utilization, costs, and quality of life over 15 years from 5 years of statin use in men without a history of myocardial infarction in the West of Scotland Coronary Prevention Study (WOSCOPS). METHODS: Six thousand five hundred and ninety-five participants aged 45-54 years were randomized to 5 years treatment with pravastatin (40 mg) or placebo. Linkage to routinely collected health records extended follow-up for secondary healthcare resource utilization to 15 years. The following new results are reported: cause-specific first and recurrent cardiovascular hospital admissions including myocardial infarction, heart failure, stroke, coronary revascularization and angiography; non-cardiovascular hospitalization; days in hospital; quality-adjusted life years (QALYs); costs of pravastatin treatment, treatment safety monitoring, and hospital admissions. RESULTS: Five years treatment of 1000 patients with pravastatin (40 mg/day) saved the NHS £710 000 (P < 0.001), including the cost of pravastatin and lipid and safety monitoring, and gained 136 QALYs (P = 0.017) over the 15-year period. Benefits per 1000 subjects, attributable to prevention of cardiovascular events, included 163 fewer admissions and a saving of 1836 days in hospital, with fewer admissions for myocardial infarction, stroke, heart failure and coronary revascularization. There was no excess in non-cardiovascular admissions or costs (or in admissions associated with diabetes or its complications) and no evidence of heterogeneity of effect over sub-groups defined by baseline cardiovascular risk. CONCLUSION: Five years' primary prevention treatment of middle-aged men with a statin significantly reduces healthcare resource utilization, is cost saving, and increases QALYs. Treatment of even younger, lower risk individuals is likely to be cost-effective.

Rosuvastatin and cardiovascular events in patients undergoing hemodialysis.

BACKGROUND: Statins reduce the incidence of cardiovascular events in patients at high cardiovascular risk. However, a benefit of statins in such patients who are undergoing hemodialysis has not been proved. METHODS: We conducted an international, multicenter, randomized, double-blind, prospective trial involving 2776 patients, 50 to 80 years of age, who were undergoing maintenance hemodialysis. We randomly assigned patients to receive rosuvastatin, 10 mg daily, or placebo. The combined primary end point was death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. Secondary end points included death from all causes and individual cardiac and vascular events. RESULTS: After 3 months, the mean reduction in low-density lipoprotein (LDL) cholesterol levels was 43% in patients receiving rosuvastatin, from a mean baseline level of 100 mg per deciliter (2.6 mmol per liter). During a median follow-up period of 3.8 years, 396 patients in the rosuvastatin group and 408 patients in the placebo group reached the primary end point (9.2 and 9.5 events per 100 patient-years, respectively; hazard ratio for the combined end point in the rosuvastatin group vs. the placebo group, 0.96; 95% confidence interval [CI], 0.84 to 1.11; P=0.59). Rosuvastatin had no effect on individual components of the primary end point. There was also no significant effect on all-cause mortality (13.5 vs. 14.0 events per 100 patient-years; hazard ratio, 0.96; 95% CI, 0.86 to 1.07; P=0.51). CONCLUSIONS: In patients undergoing hemodialysis, the initiation of treatment with rosuvastatin lowered the LDL cholesterol level but had no significant effect on the composite primary end point of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. (ClinicalTrials.gov number, NCT00240331.)

Alternans of action potential duration and amplitude in rabbits with left ventricular dysfunction following myocardial infarction.

T-wave alternans may predict the occurrence of ventricular arrhythmias in patients with left ventricular dysfunction and experimental work has linked discordant repolarization alternans to the induction of re-entry. The aim of this study was to examine the occurrence of transmural repolarization alternans and to investigate the link between alternans and ventricular arrhythmia in rabbits with left ventricular dysfunction following myocardial infarction. Optical mapping was used to record action potentials from the transmural surface of left ventricular wedge preparations from normal and post-infarction hearts during a progressive reduction in pacing cycle length at 30 and 37°C. Data were analyzed using custom software, including spectral analysis. There were no significant differences in baseline transmural electrophysiology between the groups. Post-infarction hearts had a lower threshold for both repolarization alternans (286 vs. 333 bpm, p<0.05) and ventricular arrhythmias (79 vs. 19%, p<0.01) during rapid pacing, which was not accounted for by increased transmural discordant alternans. In VF-prone hearts, alternans in optical action potential amplitude was observed and increased until 2:1 block occurred. The degree of optical action potential amplitude alternans (12.0 ± 7.0 vs. 1.8 ± 0.3, p<0.05), but not APD(90) alternans (1.4 ± 0.6 vs. 1.1 ± 0.1, p>0.05) was associated with VF inducibility during rapid pacing. Post-infarction hearts are more vulnerable to transmural alternans and ventricular arrhythmias at rapid rates. Alternans in optical action potential amplitude was associated with conduction block and VF. The data suggest that changes in optical action potential amplitude may underlie a mechanism for alternans-associated ventricular arrhythmia in left ventricular dysfunction.

Long-term follow-up of the West of Scotland Coronary Prevention Study.

BACKGROUND: The West of Scotland Coronary Prevention Study was a randomized clinical trial comparing pravastatin with placebo in men with hypercholesterolemia who did not have a history of myocardial infarction, with an average follow-up of approximately 5 years. The combined outcome of death from definite coronary heart disease or definite nonfatal myocardial infarction was reduced from 7.9 to 5.5% (P<0.001) in the treatment group. Extended follow-up data were obtained for approximately 10 years after completion of the trial. METHODS: For the survivors of the trial, all deaths, hospitalizations and deaths due to coronary events and stroke, and incident cancers and deaths from cancer were tracked with the use of a national computerized record-linkage system. The results were analyzed with time-to-event analyses and use of Cox proportional-hazards models. RESULTS: Five years after the trial ended, 38.7% of the original statin group and 35.2% of the original placebo group were being treated with a statin. In the period approximately 10 years after completion of the trial, the risk of death from coronary heart disease or nonfatal myocardial infarction was 10.3% in the placebo group and 8.6% in the pravastatin group (P=0.02); over the entire follow-up period, the rate was 15.5% in the placebo group and 11.8% in the pravastatin group (P<0.001). Similar percentage reductions were seen in the combined rate of death from coronary heart disease and hospitalization for coronary events for both periods. The rate of death from cardiovascular causes was reduced (P=0.01), as was the rate of death from any cause (P=0.03), over the entire follow-up period. There were no excess deaths from noncardiovascular causes or excess fatal or incident cancers. CONCLUSIONS: In this analysis, 5 years of treatment with pravastatin was associated with a significant reduction in coronary events for a subsequent 10 years in men with hypercholesterolemia who did not have a history of myocardial infarction.

Effect of activation sequence on transmural patterns of repolarization and action potential duration in rabbit ventricular myocardium.

Although transmural heterogeneity of action potential duration (APD) is established in single cells isolated from different tissue layers, the extent to which it produces transmural gradients of repolarization in electrotonically coupled ventricular myocardium remains controversial. The purpose of this study was to examine the relative contribution of intrinsic cellular gradients of APD and electrotonic influences to transmural repolarization in rabbit ventricular myocardium. Transmural optical mapping was performed in left ventricular wedge preparations from eight rabbits. Transmural patterns of activation, repolarization, and APD were recorded during endocardial and epicardial stimulation. Experimental results were compared with modeled data during variations in electrotonic coupling. A transmural gradient of APD was evident during endocardial stimulation, which reflected differences previously seen in isolated cells, with the longest APD at the endocardium and the shortest at the epicardium (endo: 165 ± 5 vs. epi: 147 ± 4 ms; P < 0.05). During epicardial stimulation, this gradient reversed (epi: 162 ± 4 vs. endo: 148 ± 6 ms; P < 0.05). In both activation sequences, transmural repolarization followed activation and APD shortened along the activation path such that significant transmural gradients of repolarization did not occur. This correlation between transmural activation time and APD was recapitulated in simulations and varied with changes in intercellular coupling, confirming that it is mediated by electrotonic current flow between cells. These data suggest that electrotonic influences are important in determining the transmural repolarization sequence in rabbit ventricular myocardium and that they are sufficient to overcome intrinsic differences in the electrophysiological properties of the cells across the ventricular wall.

Low serum cortisol predicts early death after acute myocardial infarction.

OBJECTIVE: To determine whether low serum cortisol concentrations are associated with adverse prognosis in patients with acute myocardial infarction. Low serum cortisol concentrations have been associated with adverse prognosis in critical illness of diverse etiology. DESIGN: Nested case-control study. SETTING: Prospective cohort study of consecutive patients admitted with acute myocardial infarction to nine Scottish hospitals. PATIENTS: A total of 100 patients who survived 30 days (controls) and 100 patients who died within 30 days (cases). MEASUREMENTS AND MAIN RESULTS: Admission cortisol concentrations were lower in patients who died than those who survived (median, 1189 nmol/L vs. 1355 nmol/L; p < .001). A cortisol concentration in the bottom quartile (<1136 nmol/L) was a strong predictor of death within 30 days and remained so after adjustment for age and cardiac troponin concentration (adjusted odds ratio, 8.78; 95% confidence interval, 3.09-24.96; p < .001). CONCLUSIONS: Patients who mount a lesser cortisol stress response to acute myocardial infarction have a poorer early prognosis.

Isoprenaline increases the slopes of restitution trajectory in the conscious rabbit with ischemic heart failure.

Roughly speaking, restitution is the dependence of recovery time of cardiac electrical activity on heart rate. Increased restitution slope is theorized to be predictive of sudden death after heart injury such as from coronary artery occlusion (ischemia). Adrenaline analogs are known to increase restitution slope in normal hearts, but their effects in failing hearts are unknown. Twenty-six rabbits underwent coronary ligation (n = 15) or sham surgery (n = 11) and implantation of a lead in the heart for recording electrocardiograms. Eight weeks later, unanesthetized rabbits were given 0.25-2.0 ml of 1 µmol/L isoprenaline intravenously, which increased heart rate. Heart rate was quantified by time between QRS peaks (RR) and heart activity duration by R to T peak time (QTp). Ligated rabbits (n = 6) had lower ejection fraction than sham rabbits (n = 7, p < 0.0001) indicative of heart failure, but similar baseline RR (269 ± 15 vs 292 ± 23 ms, p = 0.07), QTp (104 ± 17 vs 91 ± 9 ms, p = 0.1), and isoprenaline-induced minimum RR (204 ± 11 vs 208 ± 6 ms, p = 0.4). The trajectory of QTp vs TQ plots displayed hysteresis and regions of negative slope. The slope of the positive slope region was >1 in ligated rabbits (1.27 ± 0.66) and <1 in sham rabbits (0.35 ± 0.14, p = 0.004). The absolute value of the negative slope was greater in ligated rabbits (- 0.81 ± 0.52 vs - 0.35 ± 0.14, p = 0.04). Isoprenaline increased heart rate and slopes of restitution trajectory in failing hearts. The dynamics of restitution trajectory may hold clues for sudden death in heart failure patients.

Paced ventricular electrogram fractionation predicts sudden cardiac death in hypertrophic cardiomyopathy.

AIMS: Paced electrogram fractionation analysis (PEFA) has been assessed for the prediction of sudden cardiac death (SCD) in a large-scale, prospective study of patients with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS: We determined the positive predictive value (PPV) of PEFA in relation to other risk factors for SCD and outcomes in 179 patients with HCM and no prior history of cardiac arrest. Patients were followed over a mean 4.3 years (range: 1.1-6.3 years). Thirteen patients had SCD-equivalent events: four of these patients died suddenly, three were resuscitated from ventricular fibrillation (VF), and six had implantable cardioverter-defibrillator (ICD) discharges in response to VF. PEFA identified nine of these patients and another 14 non-VF patients yielding a censored PPV of between 0.19 and 0.59 that was greater than the PPV that was the formal stopping point of the trial (0.18). Eighty per cent of patients were followed for 4 years or more. The PPV for the identification of SCD in this group was 0.38 (0.17-0.59). The use of two or more conventional markers to predict SCD identified five patients with SCD-equivalent events in the 4-year follow-up group and 42 other patients without events yielding a PPV of 0.106 (confidence limits 0.02-0.15). CONCLUSION: PEFA identifies HCM patients at risk of SCD with greater accuracy than non-invasive techniques and may have an important role in determining indications for ICD prescription.

Paroxysmal bidirectional ventricular tachycardia with tachycardiomyopathy in a pregnant woman.

Palpitations in pregnancy are not an uncommon complaint. We present a case of palpitations in the third trimester related to bidirectional ventricular tachycardia with evidence, of left ventricular systolic dysfunction. The case was successfully managed with flecainide therapy and urgent elective caesarean section. The rhythm stabilised to sinus rhythm and left ventricular systolic function normalised. We discuss the possible underlying diagnosis of catecholaminergic polymorphic ventricular tachycardia with resultant tachycardiomyopathy. A literature review of bidirectional ventricular tachycardia is presented. This is the first reported case of bidirectional VT producing LV systolic dysfunction, which normalised following stabilisation of rhythm. The complex issues of management of this case in particular with regard to the pregnancy are discussed.

The link between repolarisation alternans and ventricular arrhythmia: does the cellular phenomenon extend to the clinical problem?

T-wave alternans is considered a potentially useful clinical marker for the risk of ventricular arrhythmia in patients with heart disease. Cellular repolarisation alternans is thought to underlie T-wave alternans, and moreover, to cause re-entrant ventricular arrhythmia. This review examines the experimental and clinical evidence linking repolarisation alternans and T-wave alternans with the occurrence of ventricular arrhythmia. Repolarisation alternans, manifest as alternating changes in action potential duration, is observed in isolated ventricular cardiomyocytes and in multicellular preparations. Its underlying causes are discussed particularly with respect to the role of intracellular Ca(2+). The repolarisation alternans observed at the single cell level is compared to the alternating behaviour observed in isolated multicellular preparations including the perfused ventricular wedge and Langendorff perfused heart. The evidence concerning spatial differences in repolarisation alternans is considered, particularly the situation where adjacent regions of myocardium exhibit repolarisation alternans of different phases. This extreme behaviour, known as discordant alternans, is thought to produce marked gradients of repolarisation that can precipitate unidirectional block and re-entrant ventricular arrhythmias. Finally, the difficulties in extrapolating between experimental models of alternans and arrhythmias and the clinical manifestation are discussed. The areas where experimental evidence is weak are highlighted, and areas for future research are outlined.

C-reactive protein and prediction of coronary heart disease and global vascular events in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER).

BACKGROUND: The role of C-reactive protein (CRP) in predicting vascular events and response to statin therapy remains uncertain. Additional large prospective studies are required. METHODS AND RESULTS: Baseline CRP was related to risk over 3.2 years for primary a combined end point (definite or suspected death from coronary heart disease, nonfatal myocardial infarction, and fatal or nonfatal stroke; n=865 events) and secondary (coronary heart disease events or stroke alone) and tertiary (stroke plus transient ischemic attack) end points in the Prospective Study of Pravastatin in the Elderly at Risk (n=5804 men and women; age, 70 to 82 years). CRP levels were higher in subjects who had a subsequent primary end-point event compared with those who did not (geometric mean; 3.64 mg/L [SD, 3.08 mg/L] versus 3.01 mg/L [SD, 3.05 mg/L]; P<0.0001). CRP correlated positively with body mass index and smoking status and negatively with high-density lipoprotein cholesterol. The unadjusted hazard ratio for the primary end point was 1.48 (95% CI, 1.26 to 1.74) in a comparison of top and bottom thirds for CRP, falling to 1.36 (95% CI, 1.15 to 1.61) with adjustment for established predictors and body mass index. Similar results were obtained for other end points or when results were examined separately by history of vascular disease. However, baseline CRP added minimally to risk prediction beyond conventional predictors and did not relate to the magnitude of pravastatin benefit. CONCLUSIONS: Elevated CRP minimally enhances cardiovascular disease prediction beyond established vascular risk factors and does not predict response to statin therapy in elderly subjects at risk. These data suggest that CRP has limited clinical value in cardiovascular disease risk stratification or predicting response to statin therapy in elderly people.

Heterogeneity of ventricular fibrillation dominant frequency during global ischemia in isolated rabbit hearts.

INTRODUCTION: Ventricular fibrillation (VF) studies show that ECG-dominant frequency (DF) decreases as ischemia develops. This study investigates the contribution of the principle ischemic metabolic components to this decline. METHODS AND RESULTS: Rabbit hearts were Langendorff-perfused at 40 mL/min with Tyrode's solution and loaded with RH237. Epicardial optical action potentials were recorded with a photodiode array (256 sites, 15 x 15 mm). After 60 seconds of VF (induced by burst pacing), global ischemia was produced by low flow (6 mL/min), or the solution changed to impose hypoxia (95% N2/5% CO2), low pH(o) (6.7, 80% O2/20% CO2), or raised [K+](o) (8 mM). DF of the optical signals was determined at each site. Conduction velocity (CV), action potential duration (APD90), effective refractory period (ERP), activation threshold, dV/dt(max), and membrane potential were measured in separate experiments during ventricular pacing. During VF, ischemia decreased DF in the left ventricle (LV) (to [58 +/- 6]%, P < 0.001), but not the right (RV) ([93 +/- 5]%). Raised [K+](o) reproduced this DF pattern (LV: [67 +/- 12]%, P < 0.001; RV: [95 +/- 9]%). LV DF remained elevated in hypoxia or low pH(o). During ventricular pacing, ischemia decreased CV in LV but not RV. Raised [K+](o) did not change CV in either ventricle. Ischemia and raised [K+](o) shortened APD90 without altering ERP. LV activation threshold increased in both ischemia and raised [K+](o) and was associated with diastolic depolarization and decreased dV/dt(max). CONCLUSIONS: These results suggest that during VF, decreased ECG DF in global ischemia is largely due to elevated [K+](o) affecting the activation thresholds in the LV rather than RV.

Mapping of epicardial activation in a rabbit model of chronic myocardial infarction:.

INTRODUCTION: This study examines the consequences of a large transmural apical infarct on the epicardial electrical activity in isolated rabbit hearts. METHODS AND RESULTS: Hearts were isolated 8 weeks after coronary artery ligation. Membrane voltage from the epicardial surface of the left ventricle (LV) including the infarct was monitored using the voltage sensitive dye RH237. Optical action potentials were detected from the epicardial surface of the infarct; the signal amplitude was approximately 20% of those in the noninfarcted zone (NZ). Epicardial activation mapping of the LV free wall showed that during right atrial (RA) pacing, the activation sequence was not significantly different between infarcted and sham-operated groups. However, direct stimulation of the epicardium in the NZ revealed an area of slow conduction velocity (CV approximately 5 cm/s(-1), approximately 10% of normal values) at the margin of the infarct zone (IZ). Within the IZ, CV was approximately 50% of normal. A prominent endocardial rim of myocardium in the infarct was not the source of epicardial optical signals because chemical ablation of the endocardium did not affect the epicardial activation pattern. CONCLUSION: Therefore, remnant groups of myocytes in the mid-wall and epicardium of the infarct scar support normal electrical activation during RA pacing. Areas of delayed conduction emerge only on epicardial stimulation.

Effect of pravastatin on rate of kidney function loss in people with or at risk for coronary disease.

BACKGROUND: Limited data suggest that HMG-CoA reductase inhibitors (statins) reduce rates of kidney function loss. We performed this analysis to determine whether pravastatin reduced the rate of kidney function loss over approximately 5 years in people with or at high risk for coronary disease. METHODS AND RESULTS: This was a post hoc subgroup analysis of data from 3 randomized double-blind controlled trials comparing pravastatin 40 mg/d and placebo in subjects with a previous acute coronary syndrome or who were at high cardiovascular risk. The primary outcome was the rate of change in estimated glomerular filtration rate (GFR; in mL/min per 1.73 m2/y). The Modified Diet and Renal Disease Study (MDRD) and Cockcroft-Gault equations were used to estimate GFR. We studied 18,569 participants, 3402 (18.3%) of whom had moderate chronic kidney disease as defined by an estimated GFR of 30 to 59.9 mL/min per 1.73 m2 body surface area. In subjects with moderate chronic kidney disease at baseline, pravastatin reduced the adjusted rate of kidney function loss by approximately 34%, although the absolute reduction in the rate of loss was small (0.22 mL/min per 1.73 m2/y by MDRD-GFR; 95% CI, 0.07 to 0.37). Pravastatin did not reduce the frequency of > or =25% decreases in kidney function in this group when MDRD-GFR was used to estimate GFR (relative risk [RR], 0.84; 95% CI, 0.66 to 1.06). When all 18,569 subjects were considered, pravastatin reduced the adjusted rate of kidney function loss by 8% (0.08 mL/min per 1.73 m2/y by MDRD-GFR; 95% CI, 0.01 to 0.15) and the risk of acute renal failure (RR, 0.60; 95% CI, 0.41 to 0.86) but did not significantly reduce the frequency of a > or =25% decline in kidney function by MDRD-GFR (RR, 0.94; 95% CI, 0.88 to 1.01). CONCLUSIONS: Pravastatin modestly reduced the rate of kidney function loss in people with or at risk for cardiovascular disease. However, the primary indication for the use of statins in people with or at risk for coronary events remains the reduction in mortality that results from their use.

Plasma lipoproteins and apolipoproteins as predictors of cardiovascular risk and treatment benefit in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).

BACKGROUND: Statins are important in vascular disease prevention in the elderly. However, the best method of selecting older patients for treatment is uncertain. We assessed the role of plasma lipoproteins as predictors of risk and of treatment benefit in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). METHOD AND RESULTS: The association of LDLc and HDLc with risk was examined in the 5804 70- to 82-year-old subjects of PROSPER. Baseline LDLc showed no relation to risk of the primary end point in the placebo group (P=0.27), nor did on-treatment LDLc in the pravastatin group (P=0.12). HDLc was inversely associated with risk in subjects on placebo (P=0.0019) but not in those on pravastatin (P=0.24). Risk reduction on pravastatin treatment was unrelated to baseline LDLc (P=0.38) but exhibited a significant interaction with HDLc (P=0.012). Subjects in the lowest 2 quintiles of HDLc (<1.15 mmol/L) had a risk reduction of 33% (hazard ratio, 0.67; 95% confidence limits, 0.55, 0.81; P<0.0001), whereas those with higher HDLc showed no benefit (RR, 1.06; 95% confidence limits, 0.88, 1.27; P=0.53). During follow-up, there was no relation between achieved level of LDLc or HDLc and risk. However, the change in the LDLc/HDLc ratio on statin treatment appeared to account for the effects of therapy. CONCLUSIONS: In people >70 years old, HDLc appears to be a key predictor of risk and of treatment benefit. Findings in PROSPER suggest that statin therapy could usefully be targeted to those with HDLc <1.15 mmol/L or an LDLc/HDLc ratio >3.3.

Microvascular function, metabolic syndrome, and novel risk factor status in women with cardiac syndrome X.

To characterize microvascular function, candidate risk pathways, and metabolic syndrome prevalence in women with cardiac syndrome X, 52 nondiabetic women with angiographically normal epicardial arteries but >1 mm of planar ST depression during exercise testing (patients) and 24 healthy controls of similar age were recruited. In addition to fasting blood samples and anthropometric measurements, forearm cutaneous microvascular function after iontophoresis of acetylcholine and sodium nitroprusside was assessed by laser Doppler imaging. Despite body mass index correction and a larger proportion on statin therapy, patients had high levels of insulin (p=0.016), triglycerides (p=0.018), intercellular adhesion molecule-1 (p=0.021), von Willebrand factor (p=0.005), and leptin (p=0.005) and lower levels of high-density lipoprotein cholesterol (p=0.042) compared with controls. Consistent with these data, 30% of patients but only 8% of controls fulfilled criteria for the metabolic syndrome as defined by the National Cholesterol Education Program (p=0.015). Endothelium-dependent and -independent microvascular functions were markedly impaired in patients (p<0.001), and the odds ratio for cardiac syndrome X was 7.38 (95% confidence interval 2.2 to 24.7) if the acetylcholine response was <8,710 flux units. In conclusion, women with cardiac syndrome X more commonly have metabolic syndrome and related adiposity, metabolic, and inflammatory derangements. They also have significantly impaired skin microvascular function as assessed by laser Doppler imaging, consistent with generalized vascular dysfunction, a finding with potential diagnostic implications.

Safety and tolerability of pravastatin in long-term clinical trials: prospective Pravastatin Pooling (PPP) Project.

BACKGROUND: Therapeutic decisions regarding pharmacological therapy should be based on safety and tolerability as well as efficacy data. Clinical trials designed to assess efficacy are often insufficiently powered to generate reliable safety data. METHODS AND RESULTS: The West of Scotland Coronary Prevention Study (WOSCOPS), the Cholesterol and Recurrent Events (CARE), and Long-term Intervention with Pravastatin in Ischemic Disease (LIPID) studies collectively accumulated >112 000 person-years of exposure in double-blind randomized trials comparing placebo and pravastatin (40 mg once daily). During 5 years of exposure, the incidence of fatal and nonfatal cancers was similar between pravastatin and placebo groups. No differences in noncardiovascular serious adverse events were detected. With >243 000 blood sample analyses, the percentage of patients with any abnormal liver function test after baseline sampling was similar (>3x the upper limit of normal for alanine aminotransferase: 128 [1.4%] versus 131 [1.4%] patients for pravastatin versus placebo, respectively). Study medication was withdrawn in 3 pravastatin and 7 placebo patients due to creatine phosphokinase elevations; no cases of mild or severe myopathy were reported. A Cox regression model considering treatment group, age, diabetes, smoking, whether primary or secondary prevention study, and cardiovascular serious adverse events indicates that the likelihood of discontinuing pravastatin was less than placebo. CONCLUSIONS: This prospective analysis indicates that during prolonged exposure, 40 mg of pravastatin is well tolerated, with no excess of noncardiovascular serious adverse events, including liver function abnormalities and laboratory and clinical evidence for myositis. These extensive safety and tolerability data provide important information for therapeutic decisions regarding this pharmacological agent.

Effect of pravastatin on cardiovascular events in people with chronic kidney disease.

BACKGROUND: Limited data describe the cardiovascular benefit of HMG-CoA reductase inhibitors (statins) in people with moderate chronic kidney disease (CKD). The objective of this analysis was to determine whether pravastatin reduced the incidence of cardiovascular events in people with or at high risk for coronary disease and with concomitant moderate CKD. METHODS AND RESULTS: We analyzed data from the Pravastatin Pooling Project (PPP), a subject-level database combining results from 3 randomized trials of pravastatin (40 mg daily) versus placebo. Of 19 700 subjects, 4491 (22.8%) had moderate CKD, defined by an estimated glomerular filtration rate of 30 to 59.99 mL/min per 1.73 m2 body surface area. The primary outcome was time to myocardial infarction, coronary death, or percutaneous/surgical coronary revascularization. Moderate CKD was independently associated with an increased risk of the primary outcome (adjusted HR 1.26, 95% CI 1.07 to 1.49) compared with those with normal renal function. Among the 4491 subjects with moderate CKD, pravastatin significantly reduced the incidence of the primary outcome (HR 0.77, 95% CI 0.68 to 0.86), similar to the effect of pravastatin on the primary outcome in subjects with normal kidney function (HR 0.78, 95% CI 0.65 to 0.94). Pravastatin also appeared to reduce the total mortality rate in those with moderate CKD (adjusted HR 0.86, 95% CI 0.74 to 1.00, P=0.045). CONCLUSIONS: Pravastatin reduces cardiovascular event rates in people with or at risk for coronary disease and concomitant moderate CKD, many of whom have serum creatinine levels within the normal range. Given the high risk associated with CKD, the absolute benefit that resulted from use of pravastatin was greater than in those with normal renal function.

Metabolic syndrome with and without C-reactive protein as a predictor of coronary heart disease and diabetes in the West of Scotland Coronary Prevention Study.

BACKGROUND: The National Cholesterol Education Program (NCEP) recently proposed a simple definition for metabolic syndrome. Information on the prospective association of this definition for coronary heart disease (CHD) and type 2 diabetes is currently limited. METHODS AND RESULTS: We used a modified NCEP definition with body mass index in place of waist circumference. Baseline assessments in the West of Scotland Coronary Prevention Study were available for 6447 men to predict CHD risk and for 5974 men to predict incident diabetes over 4.9 years of follow-up. Mean LDL cholesterol was similar but C-reactive protein was higher (P<0.0001) in the 26% of men with the syndrome compared with those without. Metabolic syndrome increased the risk for a CHD event [univariate hazard ratio (HR)=1.76 (95% CI, 1.44 to 2.15)] and for diabetes [univariate HR=3.50 (95% CI 2.51 to 4.90)]. Metabolic syndrome continued to predict CHD events (HR=1.30, 95% CI, 1.00 to 1.67, P=0.045) in a multivariate model incorporating conventional risk factors. Men with 4 or 5 features of the syndrome had a 3.7-fold increase in risk for CHD and a 24.5-fold increase for diabetes compared with men with none (both P<0.0001). C-reactive protein enhanced prognostic information for both outcomes. With pravastatin, men with the syndrome had similar risk reduction for CHD as compared with those without (HR, 0.73 and 0.69; pravastatin versus placebo). CONCLUSIONS: A modified NCEP metabolic syndrome definition predicts CHD events, and, more strikingly, new-onset diabetes, and thus helps identify individuals who may receive particular benefit from lifestyle measures to prevent these diseases.