Risk factors of atrial fibrillation following off-pump coronary artery bypass graft surgery: predictive value of C-reactive protein and transfusion requirement

Objectives: Considering the role of inflammatory reaction on the pathogenesis of atrial fibrillation (AF), the aim of this study is to investigate perioperative risk factors of AF, as well as to validate the predictive value of high-sensitive C-reactive protein (hsCRP), and transfusion requirement following off-pump coronary bypass surgery (OPCAB) in a prospective and observational trial. Methods: In this cohort, 315 consecutive patients with normal sinus rhythm (NSR) undergoing elective isolated OPCAB are prospectively studied. The patients were classified as either NSR or AF group according to their postoperative rhythm, which was continuously monitored for the first 6 postoperative days. Results: AF developed in 66 patients (19%). Univariate analysis demonstrated old age, pre-existing chronic renal failure, low left ventricle ejection fraction (LVEF <30%), highest hsCRP before the onset of AF, vasopressor and inotropic therapy, packed red blood cells (pRBCs) transfusion and amount of chest tube drainage as predictors of postoperative AF. In a stepwise multivariate analysis of these risk factors, low LVEF (odds ratio: 2.88; 95% confidence interval: 1.07–7.75; p = 0.037), highest hsCRP before the onset of AF (odds ratio: 1.06; 95% confidence interval: 1.01–1.11; p = 0.018), vasopressor therapy (odds ratio: 1.93; 95% confidence interval: 1.04–3.57; p = 0.038) and pRBC transfusion (odds ratio: 5.32; 95% confidence interval: 2.80–10.11; p < 0.001) remained as independent predictors of postoperative AF. Conclusions: Prophylactic strategies aimed at AF reduction may also be considered especially in patients with increased transfusion requirement, which showed highest predictive value for postoperative AF.     

Biatrial substrate properties in patients with atrial fibrillation

Introduction: The atrial substrate plays an important role in the maintenance of atrial fibrillation (AF). Further investigation of the biatrial substrate may be helpful for understanding the mechanism of AF. The aim of this study was to investigate the properties of right and left atrial (RA and LA) substrate in AF patients and their impact on the catheter ablation.
Methods: Biatrial electroanatomic mapping using a three-dimensional mapping system (NavX) was performed in 117 consecutive patients with paroxysmal (n = 99) and persistent (n = 18) AF. The biatrial voltage and total activation time (TAT) were obtained during sinus rhythm.
Results: The LA had a lower voltage (1.6 ± 0.5 vs 2.0 ± 0.6 mV, P < 0.001) than the RA. The TAT correlated with the voltage (r =–0.65, P< 0.001). The patients with persistent AF had a lower atrial voltage, higher coefficient of variance for the LA voltage, longer LA TAT, and more extensive scar than those with paroxysmal. The patients with recurrent AF after catheter ablation had a lower LA voltage and higher incidence of LA scarring than those without recurrence. A scar located in the low anteroseptal or low posterior wall of LA was related to recurrence of AF. LA scarring was the independent predictor of AF recurrence after catheter ablation.
Conclusion: The LA voltage was lower than the RA, and the atrial voltage correlated with the TAT. Electroanatomical remodeling of the atria could be crucial to the maintenance of AF. The LA substrate properties may play an important role in the recurrence of AF after catheter ablation of AF.     

The interval between prothrombin time tests and the quality of oral anticoagulants treatment in patients with chronic atrial fibrillation

BACKGROUND: The incidence of stroke in patients with atrial fibrillation (AF) can be significantly reduced with warfarin therapy especially if optimally controlled. OBJECTIVES: To evaluate the effect of the interval between consecutive prothrombin time measurements on the time in therapeutic range (INR 2-3) in a cohort of patients with AF on chronic warfarin treatment in the community. METHODS: All INR measurements available from a relatively large cohort of patients with chronic AF were reviewed and the mean interval between consecutive INR tests of each patient was correlated with the time in therapeutic range (TTR). RESULTS: Altogether 251,916 INR measurements performed in 4408 patients over a period of seven years were reviewed. Sixty percent of patients had their INR measured on average every 2 to 3 weeks and most others were followed at intervals of 4 weeks or longer. A small proportion (3.6%) had their INR measured on average every week. A significant decline in the time in therapeutic range was observed as the intervals between tests increased. At one to three weeks interval the TTR was 48%, at 4 weeks interval 45% and at 5 weeks 41% (P<0.0005). A five percent increment in TTR was observed if more tests were performed at multiplications of exactly 7 days (43% vs 48% P<0.0001). CONCLUSIONS: A better control with an increase in the TTR was observed in patients with atrial fibrillation if prothrombin time tests are performed at regular intervals of no longer than 3 weeks.     

Prolonged survival of porcine hepatocytes in cynomolgus monkeys

BACKGROUND & AIMS: Management of patients with liver failure can be a significant medical challenge, and transplantation of the liver is the only definitive therapy. Whole liver allotransplantation is limited by a shortage of human donors and the risks of the surgery in those most ill. Transplants consisting of xenogeneic hepatocytes might overcome these problems, and work in rodents indicates that such transplants can correct some metabolic deficiencies and can prevent the complications and mortality associated with hepatic failure. As a prelude to clinical application, we tested the feasibility of hepatocyte xenotransplantation in nonhuman primates. METHODS: One to 2 billion hepatocytes from outbred swine were transplanted into the spleens of cynomolgus monkeys using conventional immunosuppression to control rejection. Duration of graft function was determined based on assay for porcine albumin. RESULTS: Following a single infusion, xenogeneic hepatocytes functioned for more than 80 days and, following re-transplantation, for more than 253 days. Engraftment in the spleen was confirmed 40 days after transplantation by asialoglycoprotein receptor-directed nuclear scanning. The humoral immune response to the transplanted porcine cells had no discernible impact on the survival of the grafts. CONCLUSIONS: Xenotransplantation of hepatocytes should be explored as a readily available, minimally invasive form of therapy for hepatic failure.     

Natriuretic peptides

Natriuretic peptides (NPs) are released from the heart in response to pressure and volume overload. B-type natriuretic peptide (BNP) and N-terminal-proBNP have become important diagnostic tools for assessing patients who present acutely with dyspnea. The NP level reflects a compilation of systolic and diastolic function as well as right ventricular and valvular function. Studies suggest that using NPs in the emergency department can reduce the consumption of hospital resources and can lower costs by either eliminating the need for other, more expensive tests or by establishing an alternative diagnosis that does not require hospital stay. Caveats such as body mass index and renal function must be taken into account when analyzing NP levels. Natriuretic peptide levels have important prognostic value in multiple clinical settings, including in patients with stable coronary artery disease and with acute coronary syndromes. In patients with decompensated heart failure due to volume overload, a treatment-induced drop in wedge pressure is often accompanied by a rapid drop in NP levels. Knowing a patient's NP levels might thus assist with hemodynamic assessment and subsequent treatment titration. Monitoring NP levels in the outpatient setting might also improve patient care and outcomes.     

脊柱胸腰段骨折AF内固定手术后断钉11例临床分析

目的 探讨胸腰段脊柱骨折钉棒(AF)内固定手术后断钉的原因及预防措施.方法 回顾性分析2003年至2008年60例行(AF)钉内固定脊柱胸腰段骨折的病例,60例病例随访时间4个月至3年,有11例手术后出现椎弓根钉断裂.结果 11例断钉病例手术后神经功能恢复提高2～3级,60例中有8例出现骨折复位轻度丢失.发现手术操作技术不当、手术未作植骨或植骨方法欠妥当、过早过度负重活动、器械系统本身的设计缺陷等是断钉的主要原因.结论 手术前内固定物正确选择,手术的细致操作及正确进钉,椎间植骨并及时取出内固定物,手术后正确的康复指导可减少断钉的发生.