Carotid Doppler microembolic signals in patients one year after heart valve surgery

Doppler ultrasound has been used to detect microemboli during and after cardiopulmonary bypass (CPB). The aim of the present study was to examine the frequency of microembolic signals (MES) in patients one year after heart valve replacement, to look for possible risk factors associated with MES and for any correlation with cerebral events. One hundred patients, 69 male and 31 female, mean age 66.3 +/- 12.4 years, were examined one year after heart valve replacement. Thirty patients, 61% male and 39% female, mean age 62.5 +/- 8.7 years, who had undergone cardiovascular operations without heart valve pathology served as controls. A newly developed microemboli detector, EMEX-25 (Hatteland Instrumentering, Norway) was used to detect MES from both carotid arteries. MES were detected in 61% of the valve patients. A correlation was found between the number of MES, previous cardiovascular operations, emergency surgery and EuroSCORE (p <0.05). There was no correlation between the number of MES and the level of anticoagulation expressed as international normalization ratio (INR), atrial fibrillation, serum-cholesterol, New York heart association (NYHA) class, gender, age, valve type or valve position. The average number of MES was not increased in seven patients who had experienced major (three) or minor (transient, four) cerebral events during follow-up. In the 30 nonvalve controls, MES were detected in 46% of the patients. MES were detected in valve patients as well as in nonvalve patients one year after surgery. In valve patients, a significant correlation was found between MES and previous surgery, emergency surgery and EuroSCORE. There was no correlation between the number of MES and INR level or postoperative cerebral events.     

Microemboli detection on extracorporeal bypass circuits

Numerous authors have associated gaseous microembolization with adverse cerebral outcomes during cardiopulmonary bypass (CPB). The introduction to this review provides background on the connection between microemboli and adverse cerebral outcomes. This connection is often difficult to quantify, as outcomes depend on a number of factors, including the size of the bubble, where it passes through the patient, patient comorbidities and other factors. Nonetheless, numerous studies have shown statistically significant differences in the mean number of cerebral emboli detected in patients that stroked and those that did not, as well as for patients with major cardiac complications and patients with a longer length of hospital stay. Our introduction is followed by case reports and laboratory studies showing how monitoring for gaseous microemboli (GME) can be used to reduce the embolic load delivered to the patient through the bypass circuit. These methods include improved qualification of bypass circuit design prior to surgery, modification of priming procedures to reduce air in the circuit at the start of surgery, new methods for injecting drugs into the circuit during surgery, and better detection of removal of sources of air during surgery. The review concludes with background on the ultrasonic detection of GME, comparing through-transmission gross air detectors and Doppler ultrasound technology with fixed-beam ultrasonic imaging of emboli, a new ultrasonic technique that images moving emboli in the blood using a single ultrasound transducer element in a fixed position. This overview is meant to shed light on why different ultrasonic detection technologies report widely varying counts and emboli loads, and why fixed-beam ultrasonic imaging represents an improvement in the ability to monitor, measure and quantitate embolic load during CPB.     

The dynamic bubble trap reduces microbubbles in extracorporeal circulation and high intensity transient signals in the middle cerebral artery: a case report

Microemboli during extracorporeal circulation (ECC) might be a reason for postoperative neuropsychological dysfunction. This case report shows that reduction of microbubbles in the arterial line, as well as high intensity transient signals (HITS) in the middle cerebral artery (MCA), could be accomplished by use of a dynamic bubble trap (DBT) during routine coronary artery bypass graft (CABG) surgery in a 63-year-old male. The DBT was placed after the arterial filter, an ultrasound Doppler device was used for detection of microemboli before and after the DBT. HITS were measured by a transcranial ultrasound Doppler in both MCAs. For first 32 min of ECC, the DBTwas excluded; 54 916 microbubbles and 507 HITS were counted. In the next 30 min, blood flow was directed through the DBT. This led to a significant reduction of microbubbles from 55 888 to 18 237; accordingly, only 120 HITS were registered. A DBT, integrated in ECC for routine CABG, effectively reduces air bubbles, thus protecting the cerebrovascular system from microembolization, as demonstrated by lower HITS counts.     

70岁以上高龄心脏瓣膜手术患者术后发生便秘的影响因素分析及对策

目的探讨70岁以上高龄心脏瓣膜手术患者术后发生便秘的影响因素,制定护理对策。方法回顾性分析本院心胸外科2017年12月—2018年12月收治的53例70岁以上高龄心脏瓣膜病患者的临床资料,将术后发生便秘的32例患者作为病例组,未发生便秘的21例患者作为对照组,进行术后发生便秘的相关因素分析;以高龄心脏瓣膜病患者术后是否发生便秘为因变量,将单因素分析中有统计学意义的变量作为自变量,采用二分类非条件Logistic回归分析探讨发生便秘的影响因素。结果70岁以上高龄心脏瓣膜手术患者术后便秘的发生率为60.38%。二分类非条件Logistic回归分析结果显示,与对照组相比,病例组患者有便秘史(OR=10.481,P<0.05)、术后发生谵妄(OR=4.936,P<0.05)和术后早期下床活动不足(OR=7.953,P<0.05)差异有统计学意义。结论有便秘史、术后发生谵妄和术后早期下床活动不足是70岁以上高龄心脏瓣膜手术患者术后发生便秘的影响因素,应根据危险因素实施针对性护理措施。     

Quantification of Embolic Showers Using Radio-Frequency Based TCD Analysis

During cardiac surgery and cardiology interventions, microemboli may be generated and disperse in the systemic circulation. The amount of microemboli that ends up in cerebral blood vessels is associated with postoperative neurologic complications. During cardiac surgery a large amount of cerebral microemboli can occur at once and create so-called “cerebral embolic showers.” To correlate postoperative neurologic outcome to cerebral embolic load, a quantitative evaluation of these embolic showers is necessary. The standard monitoring technology to visualize cerebral microemboli is transcranial Doppler (TCD). Although the conventional TCD systems are equipped with software claiming to detect microembolic signals, none of the existing TCD systems is capable of an accurate estimation of the number of cerebral microemboli in embolic showers. In this study, an algorithm with a high temporal resolution, based on the radiofrequency (RF) signal of a TCD system, has been designed to quantify these showers. Evaluation by three independent observers of a training set demonstrates that the proposed method has a sensitivity of at least one order of magnitude better than the automatic detection algorithm on the existing Doppler device used. RF-based emboli detection can possibly become a standard addition to conventional Doppler methods, considering that accurate estimation of the embolic load supports quantification of neurologic risk during various surgical procedures. (E-mail: l.sauren@ctc.unimaas.nl)     

TCD技术检测缺血性脑血管病动脉内微栓子

经颅多普勒(TCD)微栓子检测技术为无创性检测手段。由于两种物质的密度差不同,反射声波信号不同,利用此原理检测动脉内微栓子。微栓子主要来自动脉、心脏。临床主要用于检测颈动脉系统脑梗死患者的动脉内微栓子。早期发现微栓子信号,可及时采取预防和治疗措施,减少脑梗死发生。     

A prospective clinical study of cerebral microemboli and neuropsychological outcome comparing vent-line and auto-venting arterial line filters: both filters are equally safe

INTRODUCTION: Microemboli are the main implicated cause of neuropsychological (NP) impairment after cardiac surgery. This prospective clinical trial compared the effect of an auto-venting arterial line filter on intraoperative cerebral microemboli and NP outcome compared to an arterial line filter with a vent line, in patients undergoing elective coronary artery bypass graft (CABG) surgery. METHODS: One hundred and ten patients received either an Avecor Affinity (n =73) or Pall AV-6 (n =37) control filter. Cerebral microemboli during cardiopulmonary bypass were recorded by transcranial Doppler monitoring of the right middle cerebral artery. Evidence of cerebral impairment was obtained by comparing patients' performance in a NP test battery (nine tests) administered 6-8 weeks postoperatively with their preoperative scores. RESULTS: During cardiopulmonary bypass, the median number and range of microemboli were 67 (5-846) and 55 (2-773) for the Avecor and AV-6 groups, respectively (p = 0.47). There was no difference in NP outcome. CONCLUSION: There is no difference in the filtering ability of vent-line and auto-vent filters as assessed by cerebral microemboli. This, together with the similar NP outcome, suggests that both types of filter are equally safe for clinical use.     

心脏瓣膜置换后早期住院患者死亡因素分析

背景：积极加强对高危患者心脏瓣膜置换前、中和置换后的处理,可降低心脏瓣膜置换后早期死亡率。 目的：分析心脏瓣膜病患者置换治疗后早期住院死亡的危险因素,提高手术治愈率。方法：回顾分析488例心脏瓣膜病患者行手术治疗作为临床资料;以置换后早期住院死亡为研究终点,采用单素及多因素Logistic回归方法分析置换后早期死亡的危险因素。结果与结论：488例心脏瓣膜置换患者中,置换后早期死亡27例,总死亡率5.5%。主要的死亡原因是低心排综合征、恶性心律失常、多器官功能衰竭。单因素分析显示：年龄≥60岁、心功能IV级、联合瓣膜手术以及同期冠状动脉旁路移植、左室射血分数≤50%、左室舒张末内径≥70 mm、体外循环时间≥120 min、主动脉阻断时间≥ 60 min与心脏瓣膜后死亡的发生具有相关性（P 〈 0.05）。多因素Logistic回归分析结果：年龄≥ 60岁、心功能IV级、瓣膜手术同期冠状动脉旁路移植、体外循环时间≥120 min、左室射血分数≤50% 、左室舒张末内径≥70 mm是影响心瓣膜置换后早期死亡的独立危险因素。重视围手术期处理,针对这些因素合理把握手术指征、选择合适的手术方式以及心肌保护,可以进一步降低这类患者手术并发症和病死率。     

体外循环术中高血糖对术后认知功能的影响

目的研究体外循环（CPB）心脏手术中高血糖症与术后认知功能障碍的关系。方法本院86例CPB下行心脏瓣膜置换术（CVR）或冠状动脉旁路移植术（CABG）的非糖尿病成年患者,在术前及术后6周用标准化神经系统检查进行认知功能评分,并在术中监测患者血糖水平,按照术中出现高血糖（〉200mg／dL）与否分为A、B两组,比较两组患者的术前术后认知功能评分,分析术中高血糖与术后认知功能障碍的关系。结果术中出现高血糖的患者,与术中未出现高血糖的患者比较,术后认知功能评分显著降低,认知功能障碍发生率明显增加（P〈0．01）。结论在接受体外循环手术的患者中,术中高血糖是术后出现认知功能障碍的独立毹险因素。     

Neurologic dysfunctions following cardiac surgery.

This article has discussed three major categories of neurologic injury following cardiac surgery. The primary pathophysiologic mechanisms for cerebral injury are thought to be related to reperfusion phenomena and neuronal cellular changes, hypoperfusion, and microemboli while on CPB. The type of symptoms the patient manifests range from fatal cerebral injury to more commonly seen episodes of mild, transient confusion. Preoperative, intraoperative, and postoperative risk factors are discussed. The critical care nurse's role in assessing early detection of changes, offering reassurance to both the family and patient, and providing continuity of care are summarized.     

老年瓣膜病患者瓣膜置换术术后死亡原因分析

目的 探讨分析老年瓣膜病患者瓣膜置换术术后死亡原因;方法 回顾性分析我院2007年2月-2013年2月收治的150例老年瓣膜病患者的临床资料,并分析对本组老年瓣膜病患者行瓣膜置换术术后发生死亡原因;结果 本组150例患者中死亡7例,占4.67%.临床经过统计分析可以得知,年龄、体外循环时间、阻断时间、术前心功能分级和心胸比与早期死亡发生有很大的关系;将这些具有显著差异因素进行多元Logistic分析结果表明,年龄、心功能、心胸比可能是造成老年心脏瓣膜置换术后早期死亡的独立危险因子（P＜0.01）.结论 老年瓣膜病患者瓣膜置换术术后死亡原因与年龄、心功能、心胸比以及患者自身疾病因素有很大的关系,临床早期治疗,及时改善患者心功能,术中谨慎操作,加强心肌保护,能够有效降低术后死亡率的发生.     

Permanent Pacemaker Implantation Following Cardiac Surgery: Indications and Long-Term Follow-Up

Background: Conduction disturbances requiring permanent pacemaker implantation after heart surgery occur in about 1.5% of patients. Early pacemaker implantation may reduce morbidity and postoperative hospital stay. We reviewed our experience with patients undergoing surgery to try and identify predictors for pacemaker requirements and patients who will remain pacemaker dependent.
Methods: We performed a retrospective review of 4,999 patients undergoing surgery between the years 1993 and 2005. Patient age was 64 ± 12 years, and 71% were males. Coronary bypass was performed in 4,071 (81%), aortic valve replacement in 675 (14%), and mitral valve replacement in 968 (18%) patients.
Results: Seventy-two patients (1.4%) required implantation of a permanent pacemaker after surgery. Indications for pacemaker implantation included complete atrioventricular block in 59, symptomatic bradycardia/slow atrial fibrillation in nine, second-degree atrioventricular block in two, and other conduction disturbances in two patients. Predictors for pacemaker requirement by multivariate analysis were left bundle branch block and aortic valve replacement (P < 0.001). Late follow-up was available in 58 patients, at 72 ± 32 months. Thirty-seven (63%) were pacemaker dependent. Predictors for late pacemaker dependency were third-degree atrioventricular block after surgery and preoperative left bundle branch block (P < 0.001).
Conclusions: Patients at high risk for pacemaker implantation after heart surgery include those with preexisting conduction disturbances, and those undergoing aortic valve replacement. Of those receiving a pacemaker, about one-third will recover at late follow-up. For patients in the high-risk group who are pacemaker dependent after surgery, we recommend implanting a permanent pacemaker at 5 days after surgery, thus enabling early mobilization and early discharge.     

风湿性心脏病二尖瓣置换术后三尖瓣返流的再手术治疗

目的分析风湿性心脏病二尖瓣置换术后再发三尖瓣返流（TR）患者的临床特点、外科手术方法和疗效,总结围手术期处理经验。方法2000年1月至2011年12月,17例风湿性心脏病二尖瓣置换术后再发三尖瓣返流的患者在我院接受单纯再次三尖瓣手术,行三尖瓣成形术10例,包括单纯DeVega成形术1例、瓣叶成形＋人工瓣环成形9例;行三尖瓣置换术7例,其中置换生物瓣4例,双叶机械瓣3例,回顾性分析其临床表现、诊治经过和预后情况。结果术后早期死亡1例（5．88％,1／17）,死于术后左心功能衰竭。术后发生低心排血量综合征3例,肾功能不全2例,呼吸功能不全2例,均成功救治。随访14例,随访时间3～9年,心功能I级2例,Ⅱ级8例,Ⅲ级4例。失访2例。结论对风湿性心脏病二尖瓣置换术后三尖瓣返流患者再手术治疗效果较好,合理掌握手术指征、手术时机和良好的围手术期处理是提高手术成功率的关键。     

The matching pursuit: a new method of characterizing microembolic signals?

Detection of clinically silent circulating microemboli within cerebral arteries by transcranial Doppler ultrasound (US) is now being widely investigated in the hope of identifying patients at increased risk for stroke. However, the widespread application of embolus detection is still limited in clinical practice because current transcranial Doppler systems have not the required sensitivity and specificity to analyze microembolic signals, particularly to distinguish between gaseous, or solid brain emboli and artefacts. In this work, we proposed to investigate the potential of a new approach for the analysis of microembolic signals via the so-called matching pursuit, which is closely related to wavelet transform and is not subject to the same limitations as the fast Fourier transform. Our preliminary results clearly indicate that matching pursuit is well suited to this task.     

动脉瘤性蛛网膜下腔出血早期认知功能减退的临床研究

目的观察动脉瘤性蛛网膜下腔出血(subarachnoid hemorrhage,SAH)患者早期认知功能减退的发生率并探讨其发生的危险因素。方法回顾性分析2016年1月至2020年8月在福建省立医院就诊的195例动脉瘤性SAH并急诊行血管内介入栓塞治疗患者的临床资料,按照术后2周简易精神状态检查(Mini-Mental State Examination,MMSE)评定结果,分为认知功能减退组(n=40)与认知功能正常组(n=155),比较两组患者性别、年龄、高血压、糖尿病、吸烟、血脂、尿酸、肌酐、抽搐表现、心肌损伤、超敏C反应蛋白(high-sensitivity C-reactive protein,hs-CRP)、格拉斯哥昏迷量表(Glasgow coma scale,GCS)、Hunt-Hess分级、术前出血巴罗神经学研究所(Barrow Neurological Institute,BNI)评分、蛛网膜下腔出血早期脑水肿评分(Subarachnoid hemorrhage early brain edema scale,SEBES)、术前脑积水、术前改良Rankin评分(modified Rankin scale,mRS)、动脉瘤位置、动脉瘤大小、介入栓塞手术方式、是否脑脊液引流、合并甲状腺机能低下、脑血管痉挛、迟发性脑梗死等指标并进行比较,应用单因素、多因素Logistic 回归分析蛛网膜下腔出血出现早期认知功能下降的危险性因素。结果单因素分析显示:认知功能减退组患者年龄、尿酸、肌酐水平高于认知功能正常组,差异有统计学意义(P<0.05)。与认知功能正常组相比,认知功能减退组在合并hs-CRP升高、抽搐、肌钙蛋白升高等临床表现、脑功能损伤评分高(Hunt-Hess分级≥3级、GCS评分≥8分、术前出血BNI评分≥3分、早期脑水肿SEBES评分≥3分)、出现围手术期并发症(术前脑积水、术前mRS评分>3分、脑血管痉挛、合并迟发性脑梗死)方面可能性更高,差异有统计学意义(P<0.05)。多因素分析示高龄(OR=7.990,95%CI:1.021~1.121,P=0.005)、高尿酸(OR=4.059,95%CI:1.000~1.011,P=0.044)、早期脑水肿SEBES评分高(OR=7.072,95%CI:2.344~277.908,P=0.008)、术后超声经颅多普勒超声(transcranial Doppler,TCD)提示脑血管痉挛(OR=8.064,95%CI:2.100~57.244,P=0.005)、合并迟发性脑梗死(OR=5.118,95%CI:1.173~9.238,P=0.024)是动脉瘤性SAH行介入栓塞术后发生早期认知功能下降的独立危险因素。结论建议对aSAH合并高龄、高尿酸、脑水肿严重、继发脑血管痉挛及迟发性脑梗死的患者进行动态的神经心理学评估,早期识别认知功能减退并积极干预。     

Early regression of left ventricular hypertrophy after aortic valve replacement by the Ross procedure detected by cine MRI.

AIM: The primary objective of our study was to assess the time course of left ventricular remodeling after the Ross procedure with the use of cine magnetic resonance imaging (MRI). METHODS: In a prospective study, 10 patients with isolated aortic valve disease were examined prior to aortic valve surgery, as well as at early follow-up (mean 4 weeks) and at late follow-up (mean 8 months) after pulmonary autograft aortic valve replacement (Ross procedure). The heart was imaged with a 1.5 T MR scanner along the short and long axes using a breath-hold, electrocardiogram (ECG)-triggered, cine gradient-echo sequence (FLASH). Myocardial mass and ventricular function were assessed. RESULTS: After aortic valve replacement, left ventricular myocardial mass (LVM) decreased by 13% (261 +/- 74 g to 230 +/- 65 g, p < 0.05) in the early postoperative period and by a further 16% in the late postoperative period to 192 +/- 31 g (p < 0.05). In addition, left ventricular end-diastolic and end-systolic volumes decreased from preoperative 187 +/- 89 mL (LV EDV) and 73 +/- 59 mL (LV ESV) to 119 +/- 55 mL and 56 +/- 42 mL, respectively, in the early postoperative period. In the late postoperative period, there was a further decrease to 98 +/- 30 (p < 0.05) and 33 +/- 19 mL, respectively. Ejection fraction did not change markedly after surgery (preoperatively 61 +/- 13% vs. 56 +/- 14% postoperatively). Patients with leading aortic stenosis were characterized by predominant regression of LVM and patients with leading aortic regurgitation by predominant regression of LV EDV (each p < 0.05). CONCLUSION: Cine MRI allows accurate assessment of left ventricular structure and geometry before and after aortic valve replacement with pulmonary autograft and is very sensitive in detecting relatively small changes of left ventricular myocardial mass and volumes early after hemodynamic relief as well as during serial assessment.     

Evaluation of an alternative S100b assay for use in cardiac surgery: relationship with microemboli and neuropsychological outcome

INTRODUCTION: The aim of the study was to investigate the relationship between S100b release, neuropsychological outcome and cerebral microemboli. Peri-operative assay of the astroglial cell protein S100b has been used as a marker of cerebral damage after cardiac surgery but potential assay cross-reactivity has limited its specificity. The present study uses an alternative enzyme-linked immunoabsorbant assay (ELISA) for serum S100b that has documented sensitivity and specificity data in patients undergoing coronary artery bypass grafting (CABG). METHODS: Fifty-five consecutive patients undergoing routine CABG surgery received serial venous S100b sampling at five time points: i) Pre-operative, ii) At the end of cardiopulmonary bypass (CPB), iii) 6 hrs, iv) 24 hrs and v) 48 hrs post skin closure. A previously described sandwich ELISA with monoclonal anti- S100b was used. This assay has a lower limit of detection of 0.04 microg/L and < 0.006% reactivity with S100a at a concentration of 100 microg/L S100a. Cerebral microemboli during surgery were recorded by transcranial Doppler monitor over the right middle cerebral artery. Evidence of cerebral impairment was obtained by comparing patients' performance in a neuropsychological battery of 9 tests administered 6-8 weeks post-operatively with their pre-operative scores. RESULTS: There was a significant increase in S100b only at the end of bypass (mean 0.30 microg/L, SD +/- 0.33 and range .00 to 1.57). S100b levels at the end of bypass did not correlate with neuropsychological outcome or microemboli counts. CONCLUSIONS: The low levels of S100b detected using the present assay, despite its high sensitivity and despite the routine use of cardiotomy suction, suggest that the assay may have higher specificity for cerebral S100b than previously used assays. There was no evidence that this assay is related to neuropsychological change or cerebral microemboli in cardiac surgery.     

3例经心尖行二尖瓣瓣中瓣手术老年患者的护理

总结3例二尖瓣置换术后老年患者经心尖行二尖瓣瓣中瓣手术的护理。护理内容如下。组建多学科照护团队,制订术前评估策略。术后监测血流动力学,改善心功能;优化气道管理,降低肺部并发症;监测凝血功能、肾功能,做好血糖管理,临时起搏器的护理,积极预防并发症的发生。实施多层面干预措施,改善患者预后。3例经过精心的治疗和护理,顺利出院,1个月后随访,恢复良好。     

Exhaled nitrite/nitrate levels as a marker of respiratory complications after heart valve surgery

Purpose

The purposes of this study are to measure the nitric oxide metabolites nitrite and nitrate (NOx) in the exhaled breath condensates (EBCs) of patients submitted to heart valve surgery and to assess the correlation between NOx levels and postoperative respiratory complications.

Materials and Methods

Exhaled breath condensate and blood samples were collected from each patient during spontaneous breathing preoperatively, during invasive mechanical ventilation in the fourth hour after surgery and 12, 24, 48, and 72 hours after the operation. Nitrite and nitrate levels in the EBC and serum were measured by chemiluminescence.

Results

Thirty-two patients were included in the study. In patients who presented with postoperative respiratory complications, the postoperative levels of NOx were significantly higher in the EBC from the fourth postoperative hour compared with those who experienced uneventful postoperative periods (P = .027). However, the preoperative and postoperative serum levels of NOx were not significantly different in between-group analyses (P = .995).

Conclusion

Our results suggest that the postoperative NOx level in the EBC is an early marker of respiratory complications after heart valve surgery. Additional studies using large cohorts are necessary to corroborate our results and to better define the clinical usefulness of assessing NOx in the EBC after cardiac surgery.     

巨大左心室瓣膜置换术的外科治疗经验

目的总结合并巨大左心室的心脏瓣膜置换术的外科治疗经验。方法1998年7月至2007年4月51例合并巨大左心室的心脏瓣膜病人实施换瓣术。其中主动脉瓣置换术34例，双瓣置换术17例；同时行左房折叠术12例，三尖瓣成形术17例。结果术后早期死亡8例（占15．7％），晚期死亡6例（占11.8％）。影响瓣膜置换术早期疗效及导致死亡的主要因素是术前严重左室扩大，舒张末直径（LVEDD）〉8．5cm；严重左室收缩功能下降，射血分数（EF）〈0．40；术后恶性心律失常和严重低心排以及多脏器功能衰竭；术后室颤和术前严重左室扩大伴收缩功能下降也是导致晚期死亡的主要原因。结论对心脏左室功能的正确评估、手术适应证和时机的选择、围术期的正确处理是治疗关键。