Randomized cross-over trial of short-term water-only fasting: metabolic and cardiovascular consequences

BACKGROUND AND AIMS

Routine, periodic fasting is associated with a lower prevalence of coronary artery disease (CAD). Animal studies show that fasting may increase longevity and alter biological parameters related to longevity. We evaluated whether fasting initiates acute changes in biomarker expression in humans that may impact short- and long-term health.

METHODS AND RESULTS

Apparently-healthy volunteers (N = 30) without a recent history of fasting were enrolled in a randomized cross-over trial. A one-day water-only fast was the intervention and changes in biomarkers were the study endpoints. Bonferroni correction required p ≤ 0.00167 for significance (p < 0.05 was a trend that was only suggestively significant). The one-day fasting intervention acutely increased human growth hormone (p = 1.1 × 10⁻⁴), hemoglobin (p = 4.8 × 10⁻⁷), red blood cell count (p = 2.5 × 10⁻⁶), hematocrit (p = 3.0 × 10⁻⁶), total cholesterol (p = 5.8 × 10⁻⁵), and high-density lipoprotein cholesterol (p = 0.0015), and decreased triglycerides (p = 1.3 × 10⁻⁴), bicarbonate (p = 3.9 × 10⁻⁴), and weight (p = 1.0 × 10⁻⁷), compared to a day of usual eating. For those randomized to fast the first day (n = 16), most factors including human growth hormone and cholesterol returned to baseline after the full 48 h, with the exception of weight (p = 2.5 × 10⁻⁴) and (suggestively significant) triglycerides (p = 0.028).

CONCLUSION

Fasting induced acute changes in biomarkers of metabolic, cardiovascular, and general health. The long-term consequences of these short-term changes are unknown but repeated episodes of periodic short-term fasting should be evaluated as a preventive treatment with the potential to reduce metabolic disease risk. Clinical trial registration (ClinicalTrials.gov): NCT01059760 (Expression of Longevity Genes in Response to Extended Fasting [The Fasting and Expression of Longevity Genes during Food abstinence {FEELGOOD} Trial]).

Usefulness of left atrial appendage volume as a predictor of embolic stroke in patients with atrial fibrillation

Stroke prevention in atrial fibrillation (AF) is guided by clinical factors with inadequate predictive power. Most thrombi observed in AF are observed in the left atrial appendage (LAA). This study was designed to determine (1) the association between LAA and the incidence of AF-related stroke and (2) the power of LAA to predict stroke. Patients (n = 48) with a history of AF and stroke were compared with control subjects (n = 48) with a history of AF but no history of stroke. Magnetic resonance images from both case and control populations were manually segmented to determine LAA volume. Patients with a history of stroke had larger LAA mean volumes than control subjects (28.8 ± 13.5 cm(3) vs 21.7 ± 8.27 cm(3), p = 0.002). Stroke risk is highest in patients with a LAA volume >34 cm(3) (multivariable OR 7.11, p = 0.003). In conclusion, larger LAA volume is associated with stroke in the setting of AF, and this measure can potentially improve risk stratification for stroke risk management in AF patients.

Cardiovascular risk among patients on clopidogrel anti-platelet therapy after placement of drug-eluting stents is modified by genetic variants in both the CYP2C19 and ABCB1 genes

Long-term (at least one year) dual anti-platelet therapy incorporating aspirin and clopidogrel is currently recommended following percutaneous coronary intervention with placement of a drug-eluting stent (DES). Genetic variants in both the ABCB1 and CYP2C19 genes have been associated with cardiovascular events among patients on clopidogrel. We examined the concurrent contribution of the CYP2C19 *2 and *17 alleles and the ABCB1 3435 alleles to one-year clinical risk among patients (n=1,034 on clopidogrel therapy following the placement of a DES. For CYP2C19*2, event rates were 8.4%, 10.9% and 44.4% for patients with 0, 1 and 2 *2 alleles, respectively (p=0.016). ABCB1 3435 was not associated with events in univariate analysis. However, 72% of patients with a *2 variant also possessed the ABCB1 3435 C allele; among these patients (*2/C genotype) the event rate for myocardial infarction (MI) was 14.2% vs. 6.9% for those lacking both *2 and C alleles (p=0.027) and for MI/death, 16.9% vs. 9.6% (p=0.046). Overall for all genotypes, the presence of the gain-of-function (protective) *17 allele significantly reduced the one-year rate of MI from 11.1% to 7.0% (p=0.045) and trended to reduce the combined rate of MI/death from 13.8% to 10.5% (p=0.182). In conclusion, the ABCB1 3435 locus and the *2 allele combine to impart a significant trend toward increased risk. This trend was largely reversed by the simultaneous carriage of one or two *17 alleles. These findings suggest that assessment of a combined genotype may improve risk assessment.

Prognostic value of B-type natriuretic peptide for cardiovascular events independent of left ventricular end-diastolic pressure

BACKGROUND

B-type natriuretic peptide (BNP) correlates with left ventricular (LV) end-diastolic pressure (LVEDP) and predicts cardiovascular events. We sought to determine whether BNP has prognostic value independent of LVEDP.

METHODS

Eligible patients were referred for coronary angiography between March 15, 2002, and April 30, 2008, at a single institution. Inclusion criteria were having BNP, LV ejection fraction (EF), and LVEDP measured within 24 hours of the angiogram. The predictive value of BNP for events independent of LVEDP, EF, and other confounders was determined.

RESULTS

The study population (n = 1,059) was followed for a mean of 1.8 +/- 1.7 years. The mean age was 63 +/- 13 years. The median BNP value was 182 pg/mL; 59% of patients had LVEDP > or =16 mm Hg. B-type natriuretic peptide and LVEDP had a modest but statistically significant correlation (r = 0.24, P < .0001). After adjustment for LVEDP and EF, the hazard ratio for the composite outcome of heart failure admissions and death was 1.37 (1.21-1.55, P < .0001) per unit increase in log BNP. After adjustment for BNP and EF, LVEDP did not predict heart failure admissions and death (hazard ratio 1.05 [0.95-1.10], per 5-mm Hg increase, P = .30). Those with BNP value below the median had longer event-free survival as compared to those with BNP value above the median, regardless of the LVEDP strata (log-rank P < .0001 for LVEDP > or =16 and <16 mm Hg).

CONCLUSION

B-type natriuretic peptide has prognostic value independent of LVEDP in this cohort with suspected coronary artery disease, suggesting this biomarker is not just a prognostic surrogate for elevated LV filling pressure.

Generating genetic risk scores from intermediate phenotypes for use in association studies of clinically significant endpoints

While previous results of genetic association studies for common, complex diseases (eg., coronary artery disease, CAD) have been disappointing, examination of multiple related genes within a physiologic pathway may provide improved resolution. This paper describes a method of calculating a genetic risk score (GRS) for a clinical endpoint by integrating data from many candidate genes and multiple intermediate phenotypes (IPs). First, the association of all single nucleotide polymorphisms (SNPs) to an IP is determined and regression beta-coefficients are used to calculate an IP-specific GRS for each individual, repeating this analysis for every IP. Next, the IPs are assessed by a second regression as predictors of the clinical endpoint. Each IP's individual GRS is then weighted by the regression beta-coefficients from the second step, creating a single, composite GRS. As an example, 3,172 patients undergoing coronary angiography were evaluated for 3 SNPs from the cholesterol metabolism pathway. Although these data provide only a preliminary example, the GRS method detected significant differences in CAD by GRS group, whereas separate genotypes did not. These results illustrate the potential of the GRS methodology for multigenic risk evaluation and suggest that such approaches deserve further examination in common, complex diseases such as CAD.

Update of antibiotic trials for secondary prevention of coronary heart disease

The possibility that infection is a stimulus for the vascular inflammation that promotes atherogenesis has spawned clinical trials of antibiotics. These have focused primarily on Chlamydia pneumoniae as a potential atherogenic agent. In contrast to pilot studies, recent large trials, capped by the Azithromycin and Coronary Events Study and PRavastatin Or AtorVastatin Evaluation and Infection Therapy mega trials, indicate that standard antibiotics (e.g., azithromycin and gatifloxacin) are ineffective for secondary cardiovascular prevention. Despite this, observations continue to mount that infection can be a stimulus for atherothrombosis. Thus, one should rethink, revise and reformulate hypotheses, and research strategies, including novel antibiotics and treatment at earlier stages of disease, rather than discard infection prematurely as a potential etiologic factor.

Optimal duration of eptifibatide infusion in percutaneous coronary intervention (an ESPRIT substudy)

Although randomized trials have clearly demonstrated the clinical efficacy with regimens of platelet glycoprotein IIb/IIIa antagonists that result in >80% inhibition of baseline platelet aggregation in percutaneous coronary intervention (PCI), there are no data available concerning the optimal duration of infusion of these agents. In an era when the length of hospitalization has a major impact on health care costs, the determination of the optimal duration of the infusion of these drugs after PCI is of great relevance. The investigators therefore sought to determine the optimal length of the infusion of eptifibatide after PCI by analyzing the outcomes of patients enrolled in the Enhanced Suppression of the Platelet IIb/IIIa Receptor With Integrilin Therapy trial who were randomized to treatment with eptifibatide.

A genomewide scan for early-onset coronary artery disease in 438 families: the GENECARD Study

A family history of coronary artery disease (CAD), especially when the disease occurs at a young age, is a potent risk factor for CAD. DNA collection in families in which two or more siblings are affected at an early age allows identification of genetic factors for CAD by linkage analysis. We performed a genomewide scan in 1,168 individuals from 438 families, including 493 affected sibling pairs with documented onset of CAD before 51 years of age in men and before 56 years of age in women. We prospectively defined three phenotypic subsets of families: (1) acute coronary syndrome in two or more siblings; (2) absence of type 2 diabetes in all affected siblings; and (3) atherogenic dyslipidemia in any one sibling. Genotypes were analyzed for 395 microsatellite markers. Regions were defined as providing evidence for linkage if they provided parametric two-point LOD scores >1.5, together with nonparametric multipoint LOD scores >1.0. Regions on chromosomes 3q13 (multipoint LOD = 3.3; empirical P value <.001) and 5q31 (multipoint LOD = 1.4; empirical P value <.081) met these criteria in the entire data set, and regions on chromosomes 1q25, 3q13, 7p14, and 19p13 met these criteria in one or more of the subsets. Two regions, 3q13 and 1q25, met the criteria for genomewide significance. We have identified a region on chromosome 3q13 that is linked to early-onset CAD, as well as additional regions of interest that will require further analysis. These data provide initial areas of the human genome where further investigation may reveal susceptibility genes for early-onset CAD.

Femoral arterial puncture management after percutaneous coronary procedures: a comparison of clinical outcomes and patient satisfaction between manual compression and two different vascular closure devices

BACKGROUND

Vascular access site management is crucial to safe, efficient and comfortable diagnostic or interventional transfemoral percutaneous coronary procedures. Two new femoral access site closure devices, Perclose and Angio-Seal , have been proposed as alternative methods to manual compression (MC). We compared these two devices and tested them in reference to standard MC for safety, effectiveness and patient preference.

METHODS

Prospective demographic, peri-procedural, and late follow-up data for 1,500 patients undergoing percutaneous coronary procedures were collected from patients receiving femoral artery closure by MC (n = 469), Perclose (n = 492), or Angio-Seal (n = 539). Peri-procedural, post-procedural, and post-hospitalization endpoints were: 1) safety of closure method; 2) efficacy of closure method; and 3) patient satisfaction.

RESULTS

Patients treated with Angio-Seal experienced shorter times to hemostasis (p < 0.0001, diagnostic and interventional) and ambulation (diagnostic, p = 0.05; interventional, p < 0.0001) than those treated with Perclose. Those treated with Perclose experienced greater access site complications (Perclose vs. Angio-Seal, p = 0.008; Perclose vs. MC, p = 0.06). Patients treated with Angio-Seal reported greater overall satisfaction, better wound healing and lower discomfort (each vs. Perclose or vs. MC, all p < or = 0.0001). For diagnostic cath only, median post-procedural length of stay was reduced by Angio-Seal (Angio-Seal vs. MC, p < 0.0001; Angio-Seal vs. Perclose, p = 0.009). No difference was seen in length of stay for interventional cases.

CONCLUSIONS

Overall, Angio-Seal performed better than Perclose or MC in reducing time to ambulation and length of stay among patients undergoing diagnostic procedures. There was a higher rate of successful deployment and shorter time to hemostasis for Angio-Seal, and this was accomplished with no increase in bleeding complications throughout the follow-up. Additionally, Angio-Seal performed better than Perclose in exhibiting a superior 30-day patient satisfaction and patient assessment of wound healing with less discomfort.

Usefulness of in-hospital prescription of statin agents after angiographic diagnosis of coronary artery disease in improving continued compliance and reduced mortality

Despite well-documented clinical benefit of the use of statins in patients with coronary artery disease (CAD) and even mild lipid elevations, studies have documented the presence of a significant "treatment gap" between those patients in whom treatment is indicated and those patients who actually receive it. It has been proposed that a prescription for statin therapy given to indicated patients at the time of initial angiographic diagnosis of CAD has the potential to improve long-term medication compliance, but this requires further evaluation. We prospectively followed 600 patients with angiographically demonstrated CAD (diameter stenosis > or = 70%) who met the National Cholesterol Education Project (NCEP) guidelines for statin therapy for an average of 3.0 years (range 2.0 to 4.6). Patients were an average of 65 years of age, 78% were men, 77% presented initially with acute ischemic syndrome, and 64 (10.7%) died during follow-up. Overall, 105 patients (18%) were discharged from the initial hospitalization with a statin prescription. At long-term follow-up, the number of patients taking statins had increased to 47%. However, long-term statin compliance was significantly higher among patients initially discharged with a statin prescription than those who were not (77% vs 40%; p < 0.0001). Additionally, those patients discharged with a statin prescription had significantly reduced mortality rate at long-term follow-up (5.7% vs 11.7%; p = 0.05). Cox hazard regression analysis, controlling for all known clinical baseline variables, confirmed the absence of a prehospital discharge statin prescription to be an independent predictor of increased mortality (hazard ratio 2.4) with a statistical trend (p = 0.06). Thus, this study demonstrates that after angiographic diagnosis of CAD, prescription of appropriate statin therapy at the time of hospital discharge improves long-term statin compliance and may significantly enhance survival.

Prospective study of pathogen burden and risk of myocardial infarction or death

BACKGROUND

We previously demonstrated that the risk of coronary artery disease (CAD) increased in relation to the number of pathogens (the "pathogen burden") in a cross-sectional study. In the present prospective study with a different patient cohort, we evaluated the effect of pathogen burden on the risk of myocardial infarction (MI) or death among CAD patients.

METHODS AND RESULTS

IgG antibodies to cytomegalovirus (CMV), hepatitis A virus (HAV), herpes simplex virus type 1 (HSV1), HSV type 2 (HSV2), Chlamydia pneumoniae and Helicobacter pylori, and C-reactive protein (CRP) levels were tested in baseline blood samples from 890 patients who had significant CAD on angiography. The mean follow-up period was 3 years. The baseline prevalence of antibodies directed against CMV, HAV, HSV1, or HSV2, but not C pneumoniae and H pylori, was significantly higher among patients who subsequently developed MI or death than among control subjects. After adjustment for traditional risk factors, number of diseased vessels, and clinical presentation, relative hazards (95% confidence limits) for MI or death were 2.0 (1. 4 to 3.2) for CMV, 1.6 (1.1 to 2.3) for HAV, and 1.5 (1.0 to 2.2) for HSV2. Increasing pathogen burden was significantly associated with increasing risk of MI or death in a dose-response fashion. Adjusted relative hazards of MI or death associated with pathogen burden were significant among individuals with low or high CRP levels.

CONCLUSIONS

The results suggest that infection plays an important role in incident MI or death and that the risk posed by infection is independently related to the pathogen burden.

Statin therapy, lipid levels, C-reactive protein and the survival of patients with angiographically severe coronary artery disease

OBJECTIVES

The joint predictive value of lipid and C-reactive protein (CRP) levels, as well as a possible interaction between statin therapy and CRP, were evaluated for survival after angiographic diagnosis of coronary artery disease (CAD).

BACKGROUND

Hyperlipidemia increases risk of CAD and myocardial infarction. For first myocardial infarction, the combination of lipid and CRP levels may be prognostically more powerful. Although lipid levels are often measured at angiography to guide therapy, their prognostic value is unclear.

METHODS

Blood samples were collected from a prospective cohort of 985 patients diagnosed angiographically with severe CAD (stenosis > or =70%) and tested for total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and CRP levels. Key risk factors, including initiation of statin therapy, were recorded, and subjects were followed for an average of 3.0 years (range: 1.8 to 4.3 years) to assess survival.

RESULTS

Mortality was confirmed for 109 subjects (11%). In multiple variable Cox regression, levels of TC, LDL, HDL and the TC:HDL ratio did not predict survival, but statin therapy was protective (adjusted hazard ratio [HR] = 0.49, p = 0.04). C-reactive protein levels, age, left ventricular ejection fraction and diabetes were also independently predictive. Statins primarily benefited subjects with elevated CRP by eliminating the increased mortality across increasing CRP tertiles (statins: HR = 0.97 per tertile, p-trend = 0.94; no statins: HR = 1.8 per tertile, p-trend < 0.0001).

CONCLUSIONS

Lipid levels drawn at angiography were not predictive of survival in this population, but initiation of statin therapy was associated with improved survival regardless of the lipid levels. The benefit of statin therapy occurred primarily in patients with elevated CRP.

Cytomegalovirus seropositivity and C-reactive protein have independent and combined predictive value for mortality in patients with angiographically demonstrated coronary artery disease

BACKGROUND

The role of inflammation in coronary artery disease (CAD) is being increasingly recognized. Markers of inflammation (eg, C-reactive protein [CRP]) and infection (eg, seropositivity to Chlamydia pneumoniae, cytomegalovirus [CMV], and Helicobacter pylori) have been proposed as risk factors for CAD, but these associations require further evaluation.

METHODS AND RESULTS

We prospectively tested whether CRP levels and IgG seropositivity to C pneumoniae, CMV, and H pylori are predictors of subsequent mortality in 985 consecutive patients with angiographically demonstrated CAD (stenosis >/=70%). Patients were followed for an average of 2.7 years (range 1.5 to 4.0 years). Patients averaged 65 years of age; 77% were men; and 110 (11.2%) died during follow-up. CRP levels were significantly elevated in nonsurvivors compared with survivors (mean CRP 3.1 mg/dL versus 1.5 mg/dL, P:=0.003). After controlling for all known baseline variables, the 2nd and 3rd tertiles of CRP compared with the 1st produced a Cox hazard ratio (HR) for mortality of 2.4 (P:=0.001). Of the 3 infectious markers tested, only seropositivity to CMV (HR=1.9, P:<0.05) was predictive of mortality. The majority of mortality risk associated with elevated CRP or CMV seropositivity occurred when both risk factors were present (P: for trend <0.0001). Other independent predictors of increased risk of mortality were age (HR=1.07 per year, P:<0.0001), left ventricular ejection fraction (HR=0.97 per percent, P:<0.0001), and diabetes mellitus (HR=1.7, P:=0.02).

CONCLUSIONS

CMV seropositivity and elevated CRP, especially when in combination, are strong, independent predictors of mortality in patients with CAD. This suggests an interesting hypothesis that a chronic, smoldering infection (CMV) might have the capacity to accelerate the atherothrombotic process.

Randomized secondary prevention trial of azithromycin in patients with coronary artery disease: primary clinical results of the ACADEMIC study

BACKGROUND

Chlamydia pneumoniae is associated with coronary artery disease (CAD), although its causal role is uncertain. A small preliminary study reported a >50% reduction in ischemic events by azithromycin, an antibiotic effective against C pneumoniae, in seropositive CAD patients. We tested this prospectively in a larger, randomized, double-blind study.

METHODS AND RESULTS

CAD patients (n=302) seropositive to C pneumoniae (IgG titers >/=1:16) were randomized to placebo or azithromycin 500 mg/d for 3 days and then 500 mg/wk for 3 months. The primary clinical end point included cardiovascular death, resuscitated cardiac arrest, nonfatal myocardial infarction (MI), stroke, unstable angina, and unplanned coronary revascularization at 2 years. Treatment groups were balanced, and azithromycin was generally well tolerated. During the trial, 47 first primary events occurred (cardiovascular death, 9; resuscitated cardiac arrest, 1; MI, 11; stroke, 3; unstable angina, 4; and unplanned coronary revascularization, 19), with 22 events in the azithromycin group and 25 in the placebo group. There was no significant difference in the 1 primary end point between the 2 groups (hazard ratio for azithromycin, 0.89; 95% CI, 0.51 to 1.61; P:=0.74). Events included 9 versus 7 occurring within 6 months and 13 versus 18 between 6 and 24 months in the azithromycin and placebo groups, respectively.

CONCLUSIONS

This study suggests that antibiotic therapy with azithromycin is not associated with marked early reductions (>/=50%) in ischemic events as suggested by an initial published report. However, a clinically worthwhile benefit (ie, 20% to 30%) is still possible, although it may be delayed. Larger (several thousand patient), longer-term (>/=3 to 5 years) antibiotic studies are therefore indicated.