心肌钙蛋白T在急性冠状动脉综合征临床分型和危险分层中的应用

目的探讨血清心肌钙蛋白T(cTnT)在急性冠状动脉综合征(ACS)临床分型和危险分层中的作用,评价cTnT水平与ACS的危险程度、心脏事件的发生率及预后的相关性。方法应用电化学发光免疫分析法检测急性心肌梗死(AMI)患者血清cTnT水平,临床诊断性能(ROC)曲线确立cTnT在AMI诊断中的决定限。结果用cTnT升高与否来判断ACS患者是否发生AMI,其诊断敏感性为100%,特异性为95.3%,AMI患者cTnT水平与其危险性相关。结论根据cTnT水平进行ACS的临床分型,能快速、准确的诊断非ST段抬高的AMI,比采用传统分型更科学、可靠与实用,更符合疾病发生的病理生理和临床特征。     

Effect of High-Intensity Ultrasound–Targeted Microbubble Destruction on Perfusion and Function of the Rat Heart Assessed by Pinhole-Gated SPECT

Although ultrasound-targeted microbubble destruction (UTMD) has been shown to induce bioeffects, UTMD is still desirable for therapeutic applications. Therefore, we studied the effects of UTMD on perfusion and function of the rat heart, assessed by ^99mTc-MIBI pinhole-gated SPECT (Ph-gSPECT) compared with biomarker release and histopathology. Fifty-two male Wistar rats were studied. UTMD was performed using SonoVue, with a mechanical index of 1.0 or 1.6. Controls were treated without microbubbles or without ultrasound application. At baseline, day 1, day 7 and day 30, 35 rats were imaged with ^99mTc-MIBI Ph-gSPECT to quantify left ventricular perfusion and function. In addition, troponin release and histopathology were investigated. No significant differences were observed for left ventricular ejection fractions, end-systolic and end-diastolic volumes, regional perfusion and functional scores up to 30 days after UTMD compared with controls. UTMD induced mild troponin release and early erythrocyte extravasation without necrosis, inflammation or fibrosis. Although UTMD has the potential to induce microlesions of the heart in small animals, these effects were transient without histological evidence of irreversible damage. Furthermore, UTMD does not induce abnormalities on perfusion or function of the heart, as assessed by Ph-gSPECT, which is reassuring concerning the use of SonoVue for potential therapeutic applications. (E-mail: sophie.hernot@gmail.com)     

血清心肌肌钙蛋白T对维持性血液透析患者心血管事件和血液透析充分性的评价价值

目的 探讨将血清心肌肌钙蛋白T(cTnT)列入维持性血液透析患者心血管事件和透析充分性评价体系的临床价值和意义.方法 将47例慢性肾衰竭并规律性进行维持性血液透析患者分为A组(25例)和B组(22例),A组给予普通血液透析(HD)4 h×3次/周,B组给予普通HD4 h×2次/周+高通量血液透析滤过(HDF)4 h×1次/周.于治疗前及治疗后每3个月检测1次血生化指标、cTnT和心脏彩超.观测终点为患者死亡或发生心血管事件或到研究截止日期.结果 B组于治疗第3个月开始血清cTnT水平较A组明显下降,并一直保持显著低于A组水平;A组于治疗第3个月开始二尖瓣口血流舒张早期流速与舒张晚期流速比值(E/A)逐渐减低,而B组维持相对恒定,到第18个月时,A组E/A开始显著低于B组;A组于治疗第3个月开始左心室射血分数(LVEF)逐渐减低,而B组维持相对恒定,到第12个月时,A组LVEF开始显著低于B组.治疗第12个月时,完成随访的42例患者血清cTnT与E/A和LVEF均呈显著正相关(r值分别为0.54和0.66,P＜0.05).经Kaplan-Meier生存曲线分析表明,第6个月时血清cTnT≥0.1 μg/L的患者在(28.5±9.7)个月的随访期内心血管事件的发生率显著高于cTnT＜0.1μg/L的患者(Log-rank检验:P=0.02).Cox回归分析表明,血清cTnT水平明显升高是心血管事件的独立预测因子.结论 cTnT水平可作为HD患者透析充分性的评价指标,对心血管事件有预测价值,规律的高通量HDF治疗有助于提高HD患者的透析充分性,改善患者的生存质量.     

CTnI、MYO、CK—MB质量联合检测在急性心肌梗死诊断中的意义

目的探讨用化学发光法检测肌红蛋白（MYO）、肌酸激酶同工酶（CK—MB）质量、肌钙蛋白（CTnI）对急性心肌梗死（AMI）的诊断价值。方法以65例AMI临床确诊病例为研究组,65例不稳定型心绞痛（UAP）,65例其他心脏病患者和50例健康体检为对照组,于不同时间用化学发光法检测MYO、CK—MB、CTnI含量,比较诊断AMI的敏感性和特异性,并随访AMI组患者心脏病性猝死及心绞痛事件发生情况,确定联合检测和独立检测的最佳时间具有的不同诊断价值。结果AMI组（症状6～24h）CTnI、MYO、CK—MB均显著高于对照组,具有显著性差异（P〈0．01）。在症状发生后的2—6h采样分析,CTnI、MYO联合诊断AMI的敏感性和特异性分别是81．8％、87．8％;89．4％、50．6％,MYO有高的阴性预示值。在症状发生后的6—12h采样分析,CTnI、MYO、CK—MB联合诊断AMI的敏感性和特异性分别是95．4％、99．6％;98．9％、80．6％;90．6％、80．9％。有较高的敏感性和特异性。在症状发生后的12～24h采样分析,cTnI、CK—MB联合诊断AMI敏感性和特异性分别为100％、100％;96．9％、87．3％,可达到最佳敏感性和特异性。在症状发生后的24—72h采样分析,cTnI诊断AMI的敏感性和特异性分别是89．5％和100％。结论联合检测MYO、CK—MB、CTnI能够更准确的诊断AMI,不同时间段各项指标的敏感性和特异性差异较大,因此根据不同的选择可提高AMI的诊断率和制定最佳治疗方案。     

心脏型脂肪酸结合蛋白对急性心肌梗死早期诊断的临床价值研究

目的探讨心脏型脂肪酸结合蛋白（H—FABP）在急性心肌梗死（AMI）早期诊断中的临床应用价值。方法将来本院的AMI疑似患者156例,按就诊时发病时间分为2组,分别在发病后0～3、3～6h内同时检测H—FABP、肌钙蛋白T（cTnT）、肌酸激酶同工酶（CK—MB）。计算各项指标的灵敏度、特异性、准确度,并进行比较分析。结果H-FABP在发病0～3h内诊断的灵敏度为70．7％,特异性为97．0％,准确度为82．4％,显著高于cTnT和CK—MB,差异有统计学意义（P〈0．05）。在发病3～6h内诊断的灵敏度为100．0％,显著高于cTnT,差异有统计学意义（P％0．05）,特异性为92．6％,准确度为97．6％。结论H—FABP是AMI早期诊断最敏感的指标,具有非常重要的临床应用价值。     

The diagnosis of myocardial infarction in critically ill patients: An agreement study

Purpose

The aim of the study was to assess agreement among 4 intensivists in diagnosing myocardial infarction (MI) in critically ill patients based on screening electrocardiograms (ECGs) and cardiac troponin (cTn) levels.

Methods

Consecutive patients admitted to a medical-surgical intensive care unit (ICU) underwent systematic screening with 12-lead ECGs and cTn measurements throughout their ICU stay. Independently, 4 raters interpreted the ECGs assessing for changes indicative of ischemia and then classified each patient as to whether they met diagnostic criteria for MI based on the screening cTn measurements and ECG results. A priori, 2 raters were designated the primary adjudicators, and their consensus was used as the reference for the agreement statistics. Agreement on MI diagnosis was calculated for the 4 raters and expressed as raw agreement, κ (chance-corrected agreement) and ? (chance-independent agreement, calculated using pairs).

Results

Among 103 enrolled patients, 37 (35.9%) had MI according to the primary adjudicators. The raw agreement for diagnosing MI was 79% (substantial), κ was 0.24 (fair), and ? ranged from 0.12 to 0.73 (slight to substantial).

Conclusions

Diagnosing MI in the ICU remains a challenge due to variable agreement in 12-lead ECG interpretation. Such variation in practice may contribute to underrecognition of MI during critical illness.     

Patterns and prognostic value of troponin, interleukin-6, and leptin after pediatric open-heart surgery

Purpose

Leptin and interleukin-6 (IL-6) are inversely correlated and associated with decreased survival in critically ill patients. We investigated changes in leptin, IL-6, and troponin in children undergoing open-heart surgery, hypothesizing that IL-6 and troponin will increase after cardiopulmonary bypass (CPB) and will be negatively correlated with leptin.

Patients and Methods

Serial blood samples were collected from 21 patients 24 hours before and up to 48 hours after surgery.

Results

Leptin levels decreased by 50% during CPB (P < .001), then gradually increased, reaching baseline levels 12 hours after surgery. The IL-6 levels increased (P < .001) during CPB, peaking 2 hours after surgery and remaining slightly elevated at 24 hours after surgery (P < .001). Leptin and IL-6 were negatively correlated (R = −0.448, P < .001). Troponin levels increased during CPB (P < .001). Postoperative leptin and troponin were inversely correlated (r = −0.535, P < .001). Patients with modest elevations in troponin levels (<20 μg/L) had a shorter aortic clamp and CPB time (P < .01), lower IL-6 peak levels (P = .03), and shorter duration of ventilation and inotropic support compared with patients with peak troponin levels greater than 20 μg/L.

Conclusions

Lower leptin and higher IL-6 levels correlated with troponin, a marker of myocardial injury. Because leptin may have cardioprotective effects, the postoperative drop in its levels may further contribute to myocardial dysfunction.     

Differential effects of a green tea-derived polyphenol (−)-epigallocatechin-3-gallate on the acidosis-induced decrease in the Ca2+ sensitivity of cardiac and skeletal muscle

(-)-Epigallocatechin-3-gallate (EGCg), a green tea-derived polyphenol, has received much attention as a protective agent against cardiovascular diseases. In this study, we determined its effects on the acidosis-induced change in the Ca(2+) sensitivity of myofilaments in myofibrils prepared from porcine ventricular myocardium and chicken pectoral muscle. EGCg (0.1 mM) significantly inhibited the decrease caused by lowering the pH from 7.0 to 6.0 in the Ca(2+) sensitivity of myofibrillar ATPase activity in cardiac muscle, but not in skeletal muscle. Studies on recombinant mouse cardiac troponin C (cTnC) and chicken fast skeletal troponin C (sTnC) using circular dichroism and intrinsic and extrinsic fluorescence spectroscopy showed that EGCg bound to cTnC with a dissociation constant of approximately 3-4 muM, but did not bind to sTnC. By presumably binding to the cTnC C-lobe, EGCg decreased Ca(2+) binding to cTnC and overcame the depressant effect of protons on the Ca(2+) sensitivity of the cardiac contractile response. To demonstrate isoform-specific effects of the action of EGCg, the pH sensitivity of the Ca(2+) response was examined in cardiac myofibrils in which endogenous cTnC was replaced with exogenous sTnC or cTnC and in skeletal myofibrils in which the endogenous sTn complex was replaced with whole cardiac Tn complex (cTn). The results suggest that the binding of EGCg to the cardiac isoform-specific TnC or Tn complex alters the effect of pH on myofilament Ca(2+) sensitivity in striated muscle.     

Reduced expression of systemic proinflammatory and myocardial biomarkers after off-pump versus on-pump coronary artery bypass surgery: A prospective randomized study

Background

The effects of off-pump (OffPCABG) and on-pump (OnPCABG) coronary artery bypass grafting (CABG) on myocardium and inflammation are unclear.

Objective

Compare the inflammatory response and myocardial injury from patients (pts) submitted to OffPCABG with those that undergo OnPCABG.

Methods

Patients with normal left ventricular function were assigned to OffPCABG (n = 40) and OnPCABG (n = 41). Blood samples were collected before and 24 hours after surgery for determination of creatine kinase (CK)–MB (CK-MB), troponin I (cTnI), interleukin (IL)–6, IL-8, P-selectin, intercellular adhesion molecule (ICAM)-1 and C-reactive protein (CRP). Mortalities were registered at 12 months.

Results

Preoperative CK-MB and cTnI levels were 3.1 ± 0.6 IU and 1.2 ± 0.5 ng/mL for OffPCABG and 3.0 ± 0.5 IU and 1.0 ± 0.2 ng/mL for OnPCABG pts. Postoperative CK-MB and cTnI levels were 13.9 ± 6.5 IU and 19.0 ± 9.0 ng/mL for OffPCABG vs 29.5 ± 11.0 IU and 31.5 ± 10.1 ng/mL for OnPCABG (P < .01). OffPCABG and OnPCABG pts had similar preoperative IL-6 (10 ± 7 and 9 ± 13 pg/mL), IL-8 (19 ± 7 and 17 ± 7 pg/mL), soluble P-selectin (70 ± 21 and 76 ± 23 pg/mL), soluble ICAM–1 (117 ± 50 and 127 ± 52 ng/mL), and CRP (0.09 ± 0.05 and 0.11 ± 0.07 mg/L). At 24 hours, for OffPCABG and OnPCABG: IL-6 was 37 ± 38* and 42 ± 41*^,† g/mL; IL-8, 33 ± 31* and 60 ± 15*^,† pg/mL; soluble P-selectin, 99 ± 26 and 172 ± 30*^,† pg/mL; soluble ICAM-1, 227 ± 47 and 236 ± 87*^,† ng/mL; and CRP, 10 ± 11* and 14 ± 13*^,† mg/L (*P < .01 vs preoperation; ^†P < .01 vs OffPCABG). Increased 24-hour postoperative CRP levels was the only marker to have significant positive correlations with events and occurred just for the OnPCABG pts. In-hospital and 1-year mortalities for the OnPCABG and OffPCABG pts were 2.0% and 2.2% (P = .1) and 2.7% and 4.7% (P = .06), respectively.

Conclusions

Thus, the absence of CPB during CABG preserves better the myocardium and attenuates inflammation—however, without improving survival.