Images in cardiovascular medicine. Unusual form of truncus arteriosus associated with 22q11 deletion

Successful treatment of sepsis caused by Staphylococcus lugdunensis in an adult with 22q11.2 deletion syndrome

A 27-year-old woman visited our hospital because of high fever. She had been diagnosed as 22q11.2 deletion syndrome (22q11.2DS) due to her cardiac history (tetralogy of Fallot), thymic hypoplasia and 22q11.2 deletion. She had a normal CD4/CD8 ratio, a slightly decreased lymphocyte count and normal serum immunoglobulin levels. Blood cultures were positive for Staphylococcus lugdunensis (S. lugdunensis). Infection route of S. lugdunensis in this case was unclear. The patient was successfully treated with several intravenous antibiotics. Infection should be considered when managing patients with 22q.11.2DS. regardless of whether their immune system is impaired.

From Pulsus to Pulseless

Computer simulations and nonlinear dynamics have provided invaluable tools for illuminating the underlying mechanisms of cardiac arrhythmias. Here, we review how this approach has led to major insights into the mechanisms of spatially discordant alternans, a key arrhythmogenic factor predisposing the heart to re-entry and lethal arrhythmias. During spatially discordant alternans, the action potential duration (APD) alternates out of phase in different regions of the heart, markedly enhancing dispersion of refractoriness so that ectopic beats have a high probability of inducing reentry. We show how, at the cellular level, instabilities in membrane voltage (ie, steep APD restitution slope) and intracellular Ca (Ca i ) cycling dynamics cause APD and the Ca i transient to alternate and how the characteristics of alternans are affected by different “modes” of the bidirectional coupling between voltage and Ca i . We illustrate how, at the tissue level, additional factors, such as conduction velocity restitution and ectopic beats, promote spatially discordant alternans. These insights have illuminated the mechanistic basis underlying the clinical association of cardiac alternans (eg, T wave alternans) with arrhythmia risk, which may lead to novel therapeutic approaches to avert sudden cardiac death.

Modulation of CD4 + CD28 null T Lymphocytes by Tumor Necrosis Factor-α Blockade in Patients With Unstable Angina

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that favors the expansion of CD4(+)CD28null T cells, an aggressive and unusual proinflammatory lymphocyte subset frequently observed in patients with unstable angina (UA). The purpose of the present ex vivo study was to evaluate whether inflammation in patients with UA may be modulated by selective blockade of TNF-alpha.

METHODS AND RESULTS

Peripheral blood samples were collected from 17 patients with UA (Braunwald's class IIIB). CD4(+)CD28null T cells were assessed by flow cytometry and expressed as a percentage of all CD4+ T cells after 24 hours of incubation of whole blood with and without increasing doses (0.1, 1, 10, and 100 microg/mL) of infliximab, an anti-TNF-alpha monoclonal antibody. In addition, CD28 expression was assessed and expressed as mean fluorescence intensity (geometric mean of the CD28 fluorescence value on all CD4+ T cells). CD4(+)CD28null T-cell percentage decreased from a median of 6.2% (range, 1.2% to 23.9%) to 4.9% (range, 1.1% to 21.9%), 4.5% (range, 1.1% to 21.6%), and 4.1% (range, 0.4% to 21.4%) after incubation with 1, 10, and 100 microg/mL of infliximab (P for trend=0.043). Analysis of CD28 mean fluorescence intensity showed that the expression of CD28 on cell surface significantly increased after incubation with increasing doses of infliximab (P for trend=0.03).

CONCLUSIONS

The findings of this ex vivo study show that CD4(+)CD28null T-cell expansion in patients with UA may be reduced by selective TNF-alpha blockade. Further studies are warranted to evaluate the clinical benefit of CD4(+)CD28null T-cell modulation.

Impact of prolonged cyclooxygenase-2 inhibition on inflammatory markers and endothelial function in patients with ischemic heart disease and raised C-reactive protein: a randomized placebo-controlled study

BACKGROUND

The impact of cyclooxygenase (COX)-2 antagonist treatment on acute coronary risk is controversial. We investigated the effect of prolonged COX-2 inhibition on inflammatory profile and endothelial function in patients with ischemic heart disease and high serum C-reactive protein (CRP) values.

METHODS AND RESULTS

In a double-blind study, 35 stable subjects on low-dose aspirin with > or =2 previous acute coronary events and 2 of 2 screening CRP values >2.0 mg/L were randomized to the COX-2 inhibitor rofecoxib (25 mg) or placebo daily for 6 months. Serum CRP, interleukin-6 (IL-6), P-selectin, matrix metalloproteinase-9 (MMP-9), and brachial artery endothelial function were evaluated. In the placebo group, CRP (median) was 3.16 mg/L (25% and 75% quartiles, 1.90 and 5.78 mg/L) at baseline and 4.22 mg/L (25% and 75% quartiles, 2.04 and 6.25 mg/L) at 6 months; in the rofecoxib group, CRP was 3.45 mg/L (25% and 75% quartiles, 2.08 and 5.78 mg/L) at baseline and 1.41 mg/L (25% and 75% quartiles, 1.17 and 4.81 mg/L) at 6 months (P=0.03). Rofecoxib compared with placebo also lowered IL-6 at 6 months (P=0.0002). There was a significant off-drug effect on CRP and IL-6 levels in the rofecoxib group 3 months after treatment (P=0.005 and P=0.009, respectively). Rofecoxib did not significantly affect P-selectin, MMP-9, and brachial artery vasoreactivity.

CONCLUSIONS

Prolonged COX-2 inhibition attenuates CRP and IL-6, does not modify P-selectin and MMP-9, and has no deleterious effect on endothelial function in stable patients with a history of recurrent acute coronary events and raised CRP. These results strengthen the rationale for evaluating the clinical benefit of COX-2 inhibition in patients with ischemic heart disease.

Inflammation as a cardiovascular risk factor

Inflammation occurs in the vasculature as a response to injury, lipid peroxidation, and perhaps infection. Various risk factors, including hypertension, diabetes, and smoking, are amplified by the harmful effects of oxidized low-density-lipoprotein cholesterol, initiating a chronic inflammatory reaction, the result of which is a vulnerable plaque, prone to rupture and thrombosis. Epidemiological and clinical studies have shown strong and consistent relationships between markers of inflammation and risk of future cardiovascular events. Inflammation can potentially be detected locally by imaging techniques as well as emerging techniques, such as identification of temperature or pH heterogeneity. It can be detected systemically by measurement of inflammatory markers. Of these, the most reliable and accessible for clinical use is currently high-sensitivity C-reactive protein. A combination of methods may provide the best identification of persons at risk for cardiovascular events who would benefit from treatment. In randomized, controlled trials, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, in the form of statins, have been shown to provide effective therapy for lowering CRP, in conjunction with their lipid-lowering effects. Although the magnitude of risk reduction associated with statin use appears to be largest for those with the highest serum levels of CRP, whether CRP reduction per se lowers cardiovascular risk is unknown.

Cyclooxygenase-2 Inhibitors

Background and Summary— Selective cyclooxygenase (COX)-2 inhibitors are increasingly being used in place of “conventional” nonsteroidal anti-inflammatory drugs (NSAIDs). This is because they are just as effective as NSAIDs in relieving arthritic pain and yet less gastrotoxic. However, the cardiovascular safety of selective COX-2 inhibitors has been questioned because they selectively reduce prostacyclin production, thus disrupting the normal homeostatic balance and promoting a prothrombotic state. These theoretical concerns appear to be supported by the results of clinical trials demonstrating an increased risk of myocardial infarction with COX-2 inhibitors compared with a conventional NSAID, and indirect comparisons of the rates of myocardial infarction among patients treated with a selective COX-2 inhibitor compared with aspirin in different trials. However, emerging data from animal, experimental and clinical studies suggest that COX-2 is atherogenic and thrombogenic, and that selective COX-2 inhibitors may be cardioprotective. Meta-analyses of randomized trials of selective COX-2 inhibitors compared with placebo have demonstrated no excess of cardiovascular events among patients allocated COX-2 inhibitors, and preliminary data from a randomized controlled trial of the selective COX-2 inhibitor meloxicam, in patients with acute coronary syndrome who were treated with aspirin, demonstrated a reduction in cardiovascular events among patients allocated the COX-2 inhibitor.

Conclusions— Continuing uncertainty regarding the direction and magnitude of any cardiovascular effects of selective COX-2 inhibitors, coupled with their widespread and increasing use, mandates prospective randomized evaluation of their efficacy and safety in patients at increased risk of future cardiovascular events.

Persistent Truncus Arteriosus

Survival of patients with persistent truncus arteriosus, otherwise known as truncus arteriosus communis, has increased over the past several years with advances in congenital heart surgery and postoperative management. Despite the fact that ongoing debate regarding timing for surgical intervention, timing and indication for truncal valve replacement, and the ideal materials to use for the right ventricle to pulmonary artery conduit, perseverance on the part of cardiac surgeons, cardiologists, and the rest of the medical team caring for these patients has resulted in longer and improved quality of life. Early, accurate diagnosis, initial stabilization, and medical management in the perinatal period, and surgical intervention are most important in preventing or decreasing long-term morbidity and mortality.

Short- and long-term COX-2 inhibition reverses endothelial dysfunction in patients with hypertension

Hypertension is associated with endothelial dysfunction that is attributable to oxidative stress and a proinflammatory state. Under these conditions, enhanced expression of cyclooxygenase-2 might lead to increased production of vasoconstrictor prostanoids and reactive oxygen species that reduce the bioavailability of endothelium-derived nitric oxide. To investigate the contribution of cyclooxygenase-2 activity to endothelial dysfunction in human hypertension, we evaluated brachial artery vasodilator function by ultrasound in 29 hypertensive patients before and after treatment with the selective cyclooxygenase-2 inhibitor celecoxib or placebo in a randomized, double-blind study. Brachial artery flow-mediated dilation improved from a baseline of 7.9+/-4.5% to 9.9+/-5.1% (P=0.005) 3 hours after the first dose and to 10.1+/-6.1% (P=0.006) after 1 week of treatment with celecoxib. In contrast, placebo treatment had no significant effect on flow-mediated dilation (8.1+/-4.4%, 8.3+/-3.5%, and 8.0+/-3.2%, respectively). Neither treatment altered nitroglycerin-mediated dilation, extent of reactive hyperemia, or baseline arterial diameter. Celecoxib treatment had no significant effect on the urinary concentrations of F2 isoprostane or thromboxane metabolites. However, urinary concentrations of the prostacyclin metabolite 2,3-dinor-6-ketoprostglandin F1alpha were significantly lower after 1 week of celecoxib treatment. Thus, cyclooxygenase-2 products contribute to endothelial dysfunction in hypertension, and treatment with a cyclooxygenase-2 inhibitor could have a beneficial effect in this setting. However, cyclooxygenase-2 inhibition also has an adverse effect on prostacyclin production that could promote thrombosis, and the net clinical consequences of improved endothelial function versus loss of prostacyclin merits further investigation.

Effects of cyclooxygenases inhibitors on vasoactive prostanoids and thrombin generation at the site of microvascular injury in healthy men

OBJECTIVE

Balance between vasoactive prostanoids that contribute to homeostasis of the circulatory system can be affected by cyclooxygenases inhibitors. Results of a recent large clinical trial show that myocardial infarction was more frequent among patients with rheumatoid arthritis treated with the selective cyclooxygenase-2 inhibitor rofecoxib compared with those treated with naproxen. Whether this difference was attributable to deleterious cardiovascular effects of rofecoxib or cardioprotective effects of naproxen has not been determined. We tested the hypothesis that naproxen, contrary to rofecoxib, exerts antithrombotic effects.

METHODS AND RESULTS

Forty-five healthy men were randomized to receive a 7-day treatment with rofecoxib (50 mg/d), naproxen (1000 mg/d), aspirin (75 mg/d), or diclofenac (150 mg/d). Formation of thromboxane, prostacyclin, and thrombin in the bleeding-time blood at the site of standardized microvascular injury was assessed before and after treatment. Naproxen, like aspirin, caused significant reduction of both thromboxane and prostacyclin, whereas diclofenac depressed prostacyclin synthesis but had no effect on tromboxane formation. Naproxen and aspirin significantly suppressed thrombin generation. Diclofenac showed a similar tendency, which did not reach statistical significance. Rofecoxib had no effect on any variables measured.

CONCLUSIONS

In healthy men, naproxen exerts an antithrombotic effect at least as potent as aspirin, whereas rofecoxib does not affect hemostatic balance.

Selective COX-2 inhibition improves endothelial function in coronary artery disease

BACKGROUND

There is an ongoing debate as to whether the gastrointestinal safety of COX-2 inhibition compared with nonsteroidal antiinflammatory drugs (NSAIDs) may come at the cost of increased cardiovascular events. In view of the large number of patients at cardiovascular risk requiring chronic analgesic therapy with COX-2 inhibitors for arthritic and other inflammatory conditions, the effects of selective COX-2 inhibition on clinically useful surrogates for cardiovascular disease, particularly endothelial function, need to be determined.

METHODS AND RESULTS

Fourteen male patients (mean age, 66+/-3 years) with severe coronary artery disease (average of 2.6 vessels with stenosis >75%) undergoing stable background therapy with aspirin and statins were included. The patients received celecoxib (200 mg BID) or placebo for a duration of 2 weeks in a double-blind, placebo-controlled, crossover fashion. After each treatment period, flow-mediated dilation of the brachial artery, high-sensitivity C-reactive protein, oxidized LDL, and prostaglandins were measured. Celecoxib significantly improved endothelium-dependent vasodilation compared with placebo (3.3+/-0.4% versus 2.0+/-0.5%, P=0.026), whereas endothelium-independent vasodilation, as assessed by nitroglycerin, remained unchanged (9.0+/-1.6% versus 9.5+/-1.3%, P=0.75). High-sensitivity C-reactive protein was significantly lower after celecoxib (1.3+/-0.4 mg/L) than after placebo (1.8+/-0.5 mg/L, P=0.019), as was oxidized LDL (43.6+/-2.4 versus 47.6+/-2.6 U/L, P=0.028), whereas prostaglandins did not change.

CONCLUSIONS

This is the first study to demonstrate that selective COX-2 inhibition improves endothelium-dependent vasodilation and reduces low-grade chronic inflammation and oxidative stress in coronary artery disease. Thus, selective COX-2 inhibition holds the potential to beneficially impact outcome in patients with cardiovascular disease.