Absence of association between whole blood viscosity and delirium after cardiac surgery: a case-controlled study

Background

Delirium after cardiothoracic surgery is common and associated with impaired outcomes. Although several mechanisms have been proposed (including changes in cerebral perfusion), the pathophysiology of postoperative delirium remains unclear. Blood viscosity is related to cerebral perfusion and thereby might contribute to the development of delirium after cardiothoracic surgery. The aim of this study was to investigate whether whole blood viscosity differs between cardiothoracic surgery patients with and without delirium.

Methods

In this observational study postoperative whole blood viscosity of patients that developed delirium (cases) were compared with non-delirious cardiothoracic surgery patients (controls). Cases were matched with the controls, yielding a 1:4 case–control study. Serial hematocrit, fibrinogen, and whole blood viscosity were determined pre-operatively and at each postoperative day. Delirium was assessed using the validated Confusion Assessment Method for the Intensive Care Unit or Delirium Screening Observation scale.

Results

In total 80 cardiothoracic surgery patients were screened of whom 12 delirious and 48 matched non-delirious patients were included. No significant difference was found between both groups in fibrinogen (p = 0.36), hematocrit (p = 0.23) and the area under curve of the whole blood viscosity between shear rates 0.02 and 50 s^-1 (p = 0.80) or between shear rates 0.02 and 5 s^-1 (p = 0.78).

Conclusion

In this case control study in cardiothoracic surgery patients changes in whole blood viscosity were not associated with the development of delirium.

Effect of metformin pretreatment on myocardial injury during coronary artery bypass surgery in patients without diabetes (MetCAB): a double-blind, randomised controlled trial

BACKGROUND

During coronary artery bypass graft (CABG) surgery, ischaemia and reperfusion damage myocardial tissue, and increased postoperative plasma troponin concentration is associated with a worse outcome. We investigated whether metformin pretreatment limits cardiac injury, assessed by troponin concentrations, during CABG surgery in patients without diabetes.

METHODS

We did a placebo-controlled, double-blind, single-centre study in an academic hospital in Nijmegen (Netherlands) in adult patients without diabetes undergoing an elective on-pump CABG procedure. We randomly assigned patients (1:1) in blocks of ten via a computer-generated randomisation sequence to either metformin hydrochloride (500 mg three times per day) or placebo (three times per day) for 3 days before surgery. The last dose was given roughly 3 h before surgery. Patients, investigators, trial staff, and the statistician were all masked to treatment allocation. The primary endpoint was the plasma concentration of high-sensitive troponin I at 6, 12, and 24 h postreperfusion after surgery, analysed in the per-protocol population with a mixed-model analysis using all these timepoints. Secondary endpoints included the occurrence of clinically relevant arrhythmias within 24 hours after reperfusion, the need for inotropic support, time to detubation, duration of stay in the intensive-care unit, and postoperative use of insulin. This study is registered with ClinicalTrials.gov, number NCT01438723.

FINDINGS

Between Nov 8, 2011, and Nov 22, 2013, we randomly assigned 111 patients to treatment (57 to metformin and 54 to placebo). Five patients dropped out from the metformin group, and six from the placebo group. 52 patients in the metformin group and 48 patients in the placebo group were included in the per-protocol analysis. Geometric mean high-sensitivity troponin I increased from 0 μg/L to 3·67 μg/L (95% CI 3·06-4·41) with metformin and to 3·32 μg/L (2·75-4·01) with placebo at 6 h after reperfusion; 2·84 μg/L (2·37-3·41) and 2·45 μg/L (2·02-2·96), respectively, at 12 h; and to 1·77 μg/L (1·47-2·12) and 1·60 μg/L (1·32-1·94) at 24 h. The concentrations did not differ significantly between the groups (difference 12·3% for all timepoints [95% CI -12·4 to 44·1] p=0·35). Occurrence of arrhythmias did not differ between groups (three [5·8%] of 52 patients who received metformin vs three [6·3%] of 48 patients who received placebo; p=1·00). There was no difference between groups in the need for inotropic support, time to detubation, duration of stay in the intensive-care unit, or postoperative use of insulin. No patients died within 30 days after surgery. Occurrence of gastrointestinal discomfort (mostly diarrhoea) was significantly higher with metformin than with placebo (11 [21·2%] of 52 vs two [4·2%] of 48 patients; p=0·01).

INTERPRETATION

Short-term metformin pretreatment, although safe, does not seem to be an effective strategy to reduce periprocedural myocardial injury in patients without diabetes undergoing CABG surgery.

FUNDING

Netherlands Organisation for Health Research and Development and Netherlands Heart Foundation.

Mediastinal staging in daily practice: endosonography, followed by cervical mediastinoscopy. Do we really need both?

OBJECTIVES

In patients with lung cancer, endosonography has emerged as a minimally invasive method to obtain cytological proof of mediastinal lymph nodes, suspicious for metastases on imaging. In case of a negative result, it is currently recommended that a cervical mediastinoscopy be performed additionally. However, in daily practice, a second procedure is often regarded superfluous. The goal of our study was to assess the additional value of a cervical mediastinoscopy, after a negative result of endosonography, in routine clinical practice.

METHODS

In a retrospective cohort study, the records of 147 consecutive patients with an indication for mediastinal lymph node staging and a negative result of endosonography were analysed. As a subsequent procedure, 124 patients underwent a cervical mediastinoscopy and 23 patients were scheduled for an intended curative resection directly. The negative predictive value (NPV) for both diagnostic procedures was determined, as well as the number of patients who needed to undergo a mediastinoscopy to find one false-negative result of endosonography (number needed to treat (NNT)). Clinical data of patients with a false-negative endosonography were analysed.

RESULTS

When using cervical mediastinoscopy as the gold standard, the NPV for endosonography was 88.7%, resulting in a NNT of 8.8 patients. For patients with fluoro-2-deoxyglucose positron emission tomography positive mediastinal lymph nodes, the NNT was 6.1. Overall, a futile thoracotomy could be prevented in 50% of patients by an additional mediastinoscopy. A representative lymph node aspirate, containing adequate numbers of lymphocytes, did not exclude metastases.

CONCLUSIONS

In patients with a high probability of mediastinal metastases, based on imaging, and negative endosonography, cervical mediastinoscopy should not be omitted, not even when the aspirate seems representative.

[Descending necrotizing mediastinitis: the need for early diagnosis and aggressive treatment]

Three patients developed descending necrotizing mediastinitis (DNM): a 44-year-old man due to poor dental status; a 54-year-old women due to a throat infection, 6 weeks after a tooth extraction; and a 30-year-old man a few days after a tooth extraction. Presenting symptoms were dyspnoea, fever, trismus, cervical oedema, and pain. The first two patients had multiple drainage of the cervical region and mediastinum in combination with pathogen-specific antibiotics. Both recovered without any complications. The third patient probably had inadequate surgical drainage of the mediastinum directly after diagnosis, and died. If the CT scan is suggestive of DNM, the patient should be referred to a thoracic surgical unit immediately. The optimal treatment consists of vigorous surgical drainage of both the neck and mediastinum with irrigation in combination with pathogen-specific antibiotic therapy. An early diagnosis followed by adequate antibiotic and surgical treatment improves the outcome in patients with DNM.

The importance of an organized follow-up for the evaluation of mortality after hospital discharge in cardiac surgery

OBJECTIVES

Does a structured follow-up, after cardiac surgery in an adult, provide additional information on the operation related mortality especially if mortality is used as an outcome parameter within the quality control?

METHOD

Mortality data of 1132 patients undergoing cardiac surgery in 2003 and 2004 in the Academic Hospital Nijmegen, The Netherlands were registered by a structured follow-up one year after surgery.

RESULTS

One year after surgery this follow-up is missing information for eight patients (0.7%). Six patients (0.5%) refused further follow-up. Of the 31 patients who died during the first postoperative year, 21 (68%) were registered thanks to this structured follow-up. In 29 patients it was possible to retrieve the cause of death.

CONCLUSION

A structured follow-up one year after cardiac surgery has a high response and not only provides a better total picture of mortality, but also information on the cause of death. Both aspects are important if mortality is used as a parameter for quality control in cardiac surgery.

Gender and physical activity one year after myocardial revascularization for stable angina

Improvement in physical activity (PA) is an important benefit for patients undergoing CABG. It is suggested that women make less improvement than men. Of 568 patients (466 men and 102 women) undergoing an isolated primary CABG for stable angina (NYHA<4) pre- and 1-year postoperative PA was registered. The Corpus Christi Heart Project criteria are used for assessing PA. The different PA-levels are coded from 1, the worst, to 5, the best. Preoperatively, female patients were older, in a higher NYHA class, and PA level was significantly different and lower 2.30+/-1.01 vs. 2.89+/-1.03 (P=0.000). At follow-up, the mean PA increased significantly for women (2.7+/-1.02) and men (3.2+/-1.06) (P=0.000). Despite this broad increase, 20% of men and 10% of women had a decreased PA. Multiple logistic regression analysis identified a preoperative high PA-level, diabetes, vascular- and pulmonary disease (odds ratio 7.11, 2.6, 2.3, 2.69) as variables that contribute independently to a worse PA for men and only high preoperative PA level (odds ratio 11.0) for women. This study confirms that patients with a preoperative high level PA are unlikely to improve PA, but in men, diabetes, vascular- and pulmonary disease are also independent risk factors.

Use of tissue expanders in adult postpneumonectomy syndrome

OBJECTIVE

Mediastinal shift and rotation after pneumonectomy can lead to severe symptomatic airway compression. Historically, a variety of treatments, such as muscle-flap transposition, pericardial fixation, and plombage, have been used. In this study we retrospectively evaluated the effectiveness of intrathoracic tissue expansion in postpneumonectomy syndrome.

METHODS

Since 1990, our center has used tissue expanders as plombage in patients with postpneumonectomy syndrome. Between 1990 and 2005, a total of 20 patients were treated. The outcome was evaluated by using preoperative, perioperative, and postoperative bronchoscopy and imaging studies. Patient satisfaction was determined with a validated questionnaire.

RESULTS

In 19 of the 20 patients, up to 3 tissue expanders were placed and filled within the pleural cavity. Access to the pleural cavity could not be obtained in 1 patient because of adhesions. Perioperative and postoperative bronchoscopic scans demonstrated decompression of the left main bronchus in 16 (84%) of 19 patients. On discharge, all patients reported improvement of their respiratory symptoms. Six (32%) patients required reoperation because of herniation (n = 2), luxation (n = 1), inadequate positioning (n = 2), and leakage of the tissue expander (n = 4). In 4 patients additional filling was performed in the outpatient clinic, with immediate improvement of respiratory distress.

CONCLUSION

Use of tissue expanders in adults with postpneumonectomy syndrome is an effective means of decompressing the remaining bronchus, thereby leading to a significant improvement in respiratory symptoms. Although 32% of patients required reoperation for complications, each complication was readily correctable.

Comparison of On-Pump or Off-Pump Coronary Artery Revascularization With Lung Resection

BACKGROUND

The simultaneous occurrence of coronary artery disease and lung cancer is rare. The best surgical treatment strategy remains controversial: performing a combined procedure with or without the use of extracorporeal circulation (ECC). The aim of this study was to compare the surgical procedure, postoperative complications, and survival of combined surgery with the use of ECC to combined surgery without ECC.

METHODS

Forty-three patients underwent a combined procedure between 1994 and 2005. Twenty-eight patients (25 male and 3 female; mean age, 66 years; range, 54 to 76 years) underwent coronary artery (CA) revascularization with ECC after the lung resection was carried out (on-pump). Fifteen patients (14 male and 1 female; mean age, 71 years; range, 50 to 79 years) had first CA revascularization without ECC followed by lung resection (off-pump). Survival was estimated by the Kaplan-Meier method and analyzed using the log-rank test and the Cox proportional hazard regression model.

RESULTS

Postoperative complications and hospital survival were not significantly different between groups. However, in the on-pump group late survival was significantly better. Late survival was significantly longer in patients without recurrent vessel disease and with stage I lung cancer.

CONCLUSIONS

These results show no significant difference in using an on-pump or off-pump technique to perform a combined cardiac and lung surgery in relation to postoperative complications and hospital survival. However, our data show a significantly longer late survival period in the on-pump group. Because the off-pump patients were older and had more advanced lung malignancy, the off-pump technique should be continued and evaluated.

The Carpentier-Edwards Classic and Physio Mitral Annuloplasty Rings: A Randomized Trial

<P>Objective: To evaluate clinical and echocardiographic outcomes for the semi-flexible Carpentier-Edwards Physio and the rigid Classic mitral annuloplasty ring. </P><P>Methods: Ninety-six patients were randomized for either a Classic (n = 53) or a Physio (n = 43) ring from October 1995 through July 1997. Mean follow-up was 5.1 years (range .1-6.6). We included standard patient characteristics at baseline and during follow-up. Analyses were adjusted for age and gender, and for factors that differed across groups at baseline. In 2002, echocardiography was performed in 74% of the survivors. </P><P>Results: We found a 16% difference in mortality: 14% in the Physio group (n = 6) and 30% in the Classic group (n = 16) (adjusted P = .41). Life table analysis shows that the absolute risk of death after 30 months is lower in the Physio group. Intra-operative repair failure occurred in 3 patients (6%) of the Classic group, and in 4 (9%) of the Physio group, resulting in mitral valve replacement. Late failure occurred in 1 patient (2%) in the Classic group, and in 4 (9%) in the Physio group. At follow-up, left ventricular function did not differ across groups (ejection fraction 45% and 48% (adjusted P = .65)). The combined NYHA class III-IV had improved for the Classic group in 42% and for the Physio group in 34%. </P><P>Conclusion: Although the 16% difference in mortality did not reach statistical significance, it is considered clinically important. No differences in morbidity, valve function, and left ventricular function were found. Further research to explain the difference in mortality is required.</P>

Combined Minimally Invasive Pulmonary Vein Isolation, Left Atrial Appendage Excision and Cardiac Resynchronization Therapy for Heart Failure: Case Report

A 76-year-old male with ischemic cardiomyopathy presented with heart failure symptoms in the absence of angina. Several hospitalizations were required due to heart failure exacerbation and paroxysmal atrial fibrillation. Electrocardiography and tissue synchronization imaging confirmed ventricular dyssynchrony, requiring biventricular pacing. After a failed attempt of percutaneous placement of the left ventricular lead, a novel minimally invasive approach was indicated. It consisted of left ventricular epicardial lead placement, microwave pulmonary vein isolation, and left atrial appendage excision through bilateral minithoracotomies. The postoperative recovery was unremarkable, with reestablishment of the ventricular synchrony and regular rhythm.

Surgical treatment of Pancoast tumours

Due to its localisation in the apex of the lung with invasion of the lower part of the brachial plexus, first ribs, vertebrae, subclavian vessels or stellate ganglion, a superior sulcus tumour causes characteristic symptoms, like arm or shoulder pain or Horner's syndrome. If rib invasion is the only feature, lysis of the rib must be evident on the chest radiograph; otherwise the tumour cannot be defined as a Pancoast tumour. It is important to adequately stage the tumour, because staging significantly influences survival. Survival is better for T3 than T4 tumours and mediastinal lymph node involvement has been found to be a negative prognostic factor. Also Horner's syndrome and incompleteness of resection worsen survival. The management of superior sulcus tumours has evolved over the past 50 years. Before 1950 it was considered to be inoperable and uniformly fatal. Shaw and Paulson introduced combined modality treatment and for many years, this combination of radiotherapy and surgery was the treatment of choice with a mean 5-year survival of approximately 30%. Postoperative radiotherapy or brachytherapy does not improve survival in patients with complete or incomplete resection. The tumour can be resected through the classic posterior Shaw-Paulson approach or the newer anterior transcervical approach, introduced by Dartevelle. This method facilitates better exposure of the extreme apex of the lung, brachial plexus and subclavian vessels. Regarding the extent of pulmonary resection, en bloc resection of the involved ribs with a lobectomy is recommended. Recent multimodality studies, involving chemoradiotherapy and surgical resection, show promising results regarding completeness of resection, local recurrence and survival, provided that appropriate staging has been carried out. However, careful patient selection and adequate perioperative management with protection of the bronchial stump or anastomosis are important to achieve reasonable rates of morbidity and mortality. As brain metastases remain one of the most common forms of relapse, further studies are needed to examine the role of prophylactic cranial irradiation in patients with complete resection. Also the addition of other chemotherapy agents or biologic agents such as angiogenesis inhibitors or tyrosine kinase inhibitors gives a new perspective in the treatment of Pancoast tumours.

Results of surgical treatment of T4 non-small cell lung cancer

OBJECTIVE

Because of location and invasion of surrounding structures, the role of surgical treatment for T4 tumors remains unclear. Extended resections carry a high mortality and should be restricted for selected patients. This study clarifies the selection process in non-small cell T4 tumors with invasion of the mediastinum, recurrent nerve, heart, great vessels, trachea, esophagus, vertebral body, and carina, or with malignant pleural effusion.

METHODS

From 1977 through 1993, 89 patients underwent resection for primary non-small cell T4 carcinomas. Resection was regarded as complete in 34 patients (38.2%) and incomplete in 55 patients (61.8%). Actuarial survival time was calculated and risk factors for late death were identified.

RESULTS

Overall hospital mortality was 19.1% (n=17). Mean 5-year survival was 23.6% for all hospital survivors, 46.2% for patients with complete resection and 10.9% for patients with incomplete resection (P=0.0009). In patients with complete resection, mean 5-year survival for patients with invasion of great vessels was 35.7%, whereas mean 5-year survival for invasion of other structures was 58.3% (P=0.05). Age, mediastinal lymph node involvement, type of operative procedure, and postoperative radiotherapy did not significantly influence survival.

CONCLUSION

In certain T4 tumors complete resection is possible, resulting in good mean 5-year survival especially for tumors with invasion of the trachea or carina. High hospital mortality makes careful patient selection imperative.

Operative risk factors of type A aortic dissection: analysis of 252 consecutive patients

OBJECTIVE

We examined operative risk factors for postoperative death after surgery for acute type A aortic dissection.

METHODS

Between 1974 and 1999, 252 patients, 163 men and 89 women (mean+/-SD age, 58+/-12 years) underwent surgery for acute type A aortic dissection. Fifty-eight (23.0%) were in cardiogenic shock at time of surgery. Most patients underwent ascending aorta replacement which was combined with aortic valve replacement by means of a composite graft in 30 (11.9%) patients and an isolated aortic valve replacement in 16 (6.3%) patients.

RESULTS

The overall operative mortality rate was 25.0% (n=63); 27.0% for patients operated upon with aortic cross-clamping, 23.7% after deep hypotherm circulatory arrest and 23.3% after antegrade selective cerebral perfusion (ASCP) (p=0.73). Multivariate analysis revealed iatrogenic dissection (p=0.0096, odds ratio=5.7), preoperative cardiopulmonary resuscitation (p=0.0095, odds ratio=5.5) and every quarter of an hour longer extracorporeal circulation (p=0.049, odds ratio=1.1) as independent risk factors for operative mortality. Aortic valve replacement or Bentall procedure (p=0.0185, odds ratio=0.3) were protective factors. There were 44 new postoperative strokes: 4.7% in the group operated upon with and 20.1% in the group without ASCP (p=0.01).

CONCLUSION

In order to avoid cardiogenic shock and preoperative cardiopulmonary resuscitation, patients with acute type A aortic dissection should be treated promptly. The choice to use an aortic valve prosthesis or Bentall procedure when applicable seems to benefit the postoperative early survival. The risk of new postoperative neurological events might be reduced by avoiding the appliance of an aortic cross-clamp and by using ASCP.