The inflammatory response to cardiopulmonary bypass: part 2--anti-inflammatory therapeutic strategies

Miniaturized extracorporeal circulation vs. off-pump coronary artery bypass grafting: What the evidence shows?

Recognition of the potentially deleterious effects of esxtracorporeal circulation led to off-pump coronary artery surgery (OPCAB) experiencing a surge in popularity in the initial decade after its conception. However, OPCAB has its own limitations and technical difficulties, such as coronary access, increased left ventricular size and reduced function, which may lead to the potential for suboptimal revascularization. As an alternative technique, miniaturized extracorporeal circulation (mECC) may provide a more controlled operative field in which the heart may be manipulated whilst minimizing the inflammatory, coagulopathic and haemodilutional effects of cardiopulmonary bypass. In this review, we outline the proposed benefits of the mECC system, discuss the pitfalls associated with mECC, and directly compare mECC to ‘off-pump’ coronary surgery for a variety of clinical and non-clinical outcomes.

Modulation of the cellular and humoral immune response to pediatric open heart surgery by methylprednisolone

BACKGROUND

With the intention to reduce overshooting immune response, glucocorticoids are frequently administered perioperatively in children undergoing open heart surgery. In a retrospective study we investigated extensively the modulation of the humoral and cellular immune response by methylprednisolone (MP).

METHODS

This study was carried out on blood samples from two groups of children who had undergone surgical correction of atrial or ventricular septal defects, either without (MP⁻, n = 10), or with MP administration (MP+, n = 23, dose median 11 (IQR 10-16) mg kg⁻¹ body weight) before cardiopulmonary bypass (CPB, duration median 42 (IQR 36-65) min). EDTA blood was obtained 24 h preoperatively, after anesthesia, at CPB begin and end, 4, 24, and 48 h after surgery, at discharge and at out-patient follow-up (median 8.2 (IQR 3.3-12.2) months after surgery). Complex blood analysis including clinical chemistry and flow cytometry were performed to monitor humoral immune response, differential blood count, lymphocyte subsets, and the degree of activation of various leukocyte subpopulations.

RESULTS

The patients' postoperative courses and follow-up were uneventful. Release of IL-6 and IL8 was reduced and that of the anti-inflammatory cytokine IL-10 upregulated by MP. Significant increase of circulating neutrophils and monocytes as inflammatory reaction to surgery and CPB contact was detected in both groups. However, invasion of monocytes to the periphery was delayed with MP. CD4+ and CD8+ T-lymphocyte counts were lower with MP treatment. B-lymphocyte count increased significantly after surgery in MP+ but remained constant in MP⁻ group.

CONCLUSIONS

MP treatment partially decreased the pro-inflammatory effect of CPB surgery and induced anti-inflammatory effect on the cellular and humoral level.

Update on the association of inflammation and atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia and is associated with significant morbidity and mortality. The pathogenesis of AF remains incompletely understood and management remains a difficult task. Over the past decade there has been accumulating evidence implicating inflammation in the pathogenesis of AF. Inflammation appears to play a significant role in the initiation and perpetuation of AF as well as the prothrombotic state associated with AF. Inflammatory biomarkers (C-reactive protein and interleukin-6) have been shown to be associated with the future development, recurrence and burden of AF, and the likelihood of successful cardioversion. Therapies directed at attenuating the inflammatory burden appear promising. Animal and clinical studies have evaluated statins, angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers, and corticosteroids for the treatment or prevention of AF. The purpose of this review is to provide current evidence on the relationship between inflammation and AF and potential therapies available to modulate the inflammatory state in AF.

Benefits and Risks of Corticosteroid Prophylaxis in Adult Cardiac Surgery

Background— Cardiopulmonary bypass and cardiac surgery are associated with a significant systemic inflammatory response that may increase postoperative complications. This meta-analysis assessed whether the benefits and risks of corticosteroid use were dose dependent in adult cardiac surgery.

Methods and Results— Randomized controlled trials of the use of corticosteroid prophylaxis in adult cardiac surgery (>18 years of age) requiring cardiopulmonary bypass were selected from MEDLINE (1966 to August 1, 2008), EMBASE (1988 to August 1, 2008), and the Cochrane controlled trials register without any language restrictions. A total of 3323 patients from 50 randomized controlled trials were identified and subject to meta-analysis. Corticosteroid prophylaxis reduced the risk of atrial fibrillation (25.1% versus 35.1%; number needed to treat, 10; relative risk, 0.74; 95% confidence interval [CI], 0.63 to 0.86; P <0.01) and length of stay in the intensive care unit (weighted mean difference, −0.37 days; 95% CI, −0.21 to −0.52; P <0.01) and hospital (weighted mean difference, −0.66 days; 95% CI, −0.77 to −1.25; P =0.03) compared with placebo. The use of corticosteroid was not associated with an increased risk of all-cause infection (relative risk, 0.93; 95% CI, 0.61 to 1.41; P =0.73), but hyperglycemia requiring insulin infusion after corticosteroid prophylaxis was common (28.2%; relative risk, 1.49; 95% CI, 1.11 to 2.01; P <0.01). No additional benefits were found on all outcomes beyond a total dose of 1000 mg hydrocortisone, and very high doses of corticosteroid were associated with prolonged mechanical ventilation.

Conclusions— Evidence suggests that low-dose corticosteroid is as effective as high-dose corticosteroid in reducing the risk of atrial fibrillation and duration of mechanical ventilation but with fewer potential side effects in adult cardiac surgery.

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Traditional anticoagulant agents such as vitamin K antagonists (VKAs), unfractionated heparin (UFH), low molecular weight heparins (LMWHs) and fondaparinux have been widely used in the prevention and treatment of thromboembolic diseases. However, these agents are associated with limitations, such as the need for regular coagulation monitoring (VKAs and UFH) or a parenteral route of administration (UFH, LMWHs and fondaparinux).

Several non-VKA oral anticoagulants (NOACs) are now widely used in the prevention and treatment of thromboembolic diseases and in stroke prevention in non-valvular atrial fibrillation. Unlike VKAs, NOACs exhibit predictable pharmacokinetics and pharmacodynamics. They are therefore usually given at fixed doses without routine coagulation monitoring. However, in certain patient populations or special clinical circumstances, measurement of drug exposure may be useful, such as in suspected overdose, in patients experiencing a hemorrhagic or thromboembolic event during the treatment’s period, in those with acute renal failure, in patients who require urgent surgery or in case of an invasive procedure. This article aims at providing guidance on laboratory testing of classic anticoagulants and NOACs.