Christoph Ellenberger

Chronic β blockade is associated with a better outcome after elective noncardiac surgery than acute β blockade: a single-center propensity-matched cohort study.

Background:Current guidelines on perioperative care recommend the prophylactic use of &bgr; blockers in high-risk patients undergoing noncardiac surgery. However, recent studies show that, in some instances, perioperative &bgr; blockade can cause harm. Furthermore, chronic &bgr; blockade, titrated to effect before surgery, may be superior to acute perioperative &bgr; blockade. The primary objective of this study was to compare major acute cardiac outcomes in patients who underwent surgery with chronic &bgr; blocker therapy with those in patients with acute &bgr;-blocker therapy. Methods:Data were collected for 10,691 consecutive patients undergoing elective noncardiac surgery between April 1, 2008, and April 30, 2010. Propensity scores, estimating the probability of receiving a preoperative &bgr; blocker, were calculated to match (1:1) the patients with acute and chronic &bgr;-blocker therapy. The primary outcome was a composite of myocardial infarction, nonfatal cardiac arrest, and perioperative mortality. The rate of cardiac events was compared in the matched cohorts. Results:A total of 962 patients were chronically treated with a &bgr; blocker before surgery; in 436 patients, the &bgr; blocker was administrated acutely. Propensity score matching created 301 patient pairs who were well-balanced for major comorbidities, concomitant drug use, and type of surgery. The primary outcome was observed in 9 (3.0%) chronic versus 24 (8.0%) acute &bgr;-blocked patients (relative risk, 2.67; 95% CI, 1.27–5.60; P = 0.011). Conclusions:Acute &bgr; blockade, initiated within the first 2 days after surgery, was associated with worse cardiac outcome compared with a matched cohort of patients who underwent surgery on chronic &bgr; blockade. These results should be validated in a larger prospective trial.

Short-Term Preoperative High-Intensity Interval Training in Patients Awaiting Lung Cancer Surgery: A Randomized Controlled Trial

Introduction: Impairment in aerobic fitness is a potential modifiable risk factor for postoperative complications. In this randomized controlled trial, we hypothesized that a high‐intensity interval training (HIIT) program enhances cardiorespiratory fitness before lung cancer surgery and therefore reduces the risk of postoperative complications. Methods: Patients with operable lung cancer were randomly assigned to usual care (UC) (n = 77) or preoperative rehabilitation based on HIIT (Rehab) (n = 74). Maximal cardiopulmonary exercise testing and the 6‐minute walk test were performed twice before surgery. The primary outcome measure was a composite of death and in‐hospital postoperative complications. Results: The groups were well balanced in terms of patient characteristics. During the preoperative waiting period (median 25 days), the peak oxygen consumption and the 6‐minute walking distance increased (median +15%, interquartile range, 25th to 75 percentile [IQR25%–75%, %] = +9% to +22%, p = 0.003 and +15%, IQR25%–75% = +8% to +28%, p < 0.001, respectively) in the Rehab group, whereas peak oxygen consumption declined in the UC group (median –8%, IQR25%–75% = –16% to 0%], p = 0.005). The primary end point did not differ significantly between the two groups: at least one postoperative complication developed in 27 of the 74 patients (35.5%) in the Rehab group and 39 of 77 patients (50.6%) in the UC group (p = 0.080). Notably, the incidence of pulmonary complications was lower in the Rehab compared with in the UC group (23% versus 44%, p = 0.018), owing to a significant reduction in atelectasis (12.2% versus 36.4%, p < 0.001), and this decrease was accompanied by a shorter length of stay in the postanesthesia care unit (median –7 hours, IQR25%–75% = –4 to –10). Conclusions: In this randomized controlled trial, preoperative HIIT resulted in significant improvement in aerobic performances but failed to reduce early complications after lung cancer resection.

Cardiovascular response to acute normovolaemic haemodilution in patients with severe aortic stenosis: assessment with transoesophageal echocardiography

Using multiplane transoesophageal echocardiography (TOE), we investigated the haemodynamic response to acute normovolaemic haemodilution (ANH) in anaesthetised patients with critical aortic stenosis. Twenty‐eight patients were randomly assigned to ANH or control groups. In the control group, haemodynamic data remained unchanged over a 20‐min period. In the ANH group, haemoglobin levels decreased from a mean (SD) of 134 (7) to 91 (9) g.l−1 (p < 0.001) whereas stroke volume, central venous pressure and left ventricular (LV) end‐diastolic area all increased significantly (mean (SD) +15 (6) ml; +2.0 (1.1) mmHg; +2.1 (0.8) cm2, respectively). During ANH, the accelerated blood flow through the stenotic valve caused an increased loss (SD) in LV stroke work: from 24 (8)% to 30 (10)%), (p < 0.01). Hence, lowering viscosity with ANH resulted in improved venous return, higher cardiac preload and increased stroke volume. However, this adaptive haemodynamic response was limited by less efficient LV stroke work due to dissipation of fluid kinetic energy.

Comparison of cardiac output as assessed by transesophageal echo-Doppler and transpulmonary thermodilution in patients undergoing thoracic surgery

STUDY OBJECTIVE To evaluate the accuracy of cardiac index (CI) as measured by echo-transesophageal Doppler monitoring (echo-TDM) with CI measured by the transpulmonary thermodilution technique. DESIGN Prospective, observational study. SETTING University hospital. PATIENTS 16 patients scheduled for elective lung cancer resection. INTERVENTIONS Patients underwent two-lung ventilation (TLV) and one-lung ventilation (OLV). MEASUREMENTS AND MAIN RESULTS CI measurements were analyzed using Bland-Altman plots. Absolute values of CI as measured by both devices were highly correlated (r(2) ranging from 0.72 to 0.77), as were relative changes in CI after the start of OLV (r(2) = 0.48, P = 0.006). Before, during, and after OLV, TDM-CI biases were 0.46 +/- 0.28 L/min/m(2), 0.25 +/- 0.18 L/min/m(2), and 0.35 +/- 0.29 L/min/m(2), respectively. Limits of agreement remained stable throughout the three measurement periods (range -1.08 to 0.21 L/min/m(2)). The mean percentage error of CI measurements was 21.9% compared with the thermodilution technique. Although no adverse events were reported, 11% of measurement sets were incomplete due to poor signal detection. CONCLUSIONS Echo-TDM is a safe technique, allowing continuous semi-invasive assessment of hemodynamic changes in most patients undergoing open-chest surgery. Doppler-derived CI values showed significant biases and moderate clinical agreement with transpulmonary thermodilution during TLV and OLV.

Clinical Review: Management of weaning from cardiopulmonary bypass after cardiac surgery

A sizable number of cardiac surgical patients are difficult to wean off cardiopulmonary bypass (CPB) as a result of structural or functional cardiac abnormalities, vasoplegic syndrome, or ventricular dysfunction. In these cases, therapeutic decisions have to be taken quickly for successful separation from CPB. Various crisis management scenarios can be anticipated which emphasizes the importance of basic knowledge in applied cardiovascular physiology, knowledge of pathophysiology of the surgical lesions as well as leadership, and communication between multiple team members in a high-stakes environment. Since the mid-90s, transoesophageal echocardiography has provided an opportunity to assess the completeness of surgery, to identify abnormal circulatory conditions, and to guide specific medical and surgical interventions. However, because of the lack of evidence-based guidelines, there is a large variability regarding the use of cardiovascular drugs and mechanical circulatory support at the time of weaning from the CPB. This review presents key features for risk stratification and risk modulation as well as a standardized physiological approach to achieve successful weaning from CPB.

Effects of methylene blue on propofol requirement during anaesthesia induction and surgery

Delayed emergence from anaesthesia and neurological disturbances have been reported in patients undergoing parathyroidectomy who received methylene blue (MB) pre‐operatively. We hypothesised that MB would decrease propofol requirements. The Bispectral index (BIS) and a target‐controlled infusion of propofol were used in two groups of 11 matched patients. Patients in one group were pretreated with MB. During induction, clinical sedation scores and BIS values were significantly lower at the predicted effect‐site propofol concentration of 2 μg.ml−1 in the MB compared with the control group. Intra‐operatively, although similar BIS values were achieved in the two groups, patients pretreated with MB required a mean 50% lower dose of propofol compared with controls. In view of these findings, care should be taken to ensure an adequate depth of anaesthesia by titrating the administration of anaesthetic agents whenever MB is infused peri‐operatively.

Thirty-day Outcome Following CoreValve Evolut R Transcatheter Aortic Valve Implantation: An All-comers Prospective Study

INTRODUCTION AND OBJECTIVES There are scarce clinical outcomes data on the new generation recapturable and repositionable CoreValve Evolut R. METHODS Data on all-comer patients undergoing transcatheter aortic valve implantation (TAVI) with the Evolut R for severe symptomatic aortic stenosis at a single center were prospectively collected between February 2015 and April 2016. Clinical endpoints were independently adjudicated according to the Valve Academic Research Consortium-2 criteria. Primary outcomes consisted of early safety composite endpoints and 30-day device success. The incidence of new permanent pacemaker implantation was recorded. RESULTS Among the 83 patients undergoing TAVI during this period, 71 (85.5% of the population; median age, 83.0 [interquartile range, 80.0-87.0] years; Society of Thoracic Surgeons scores, 4.8±3.5%) were suitable for Evolut R implantation and were included in the analysis. Repositioning was performed in 26.8% of the procedures. The early safety composite endpoint was observed in 11.3% of patients at 30 days, with 2.8% all-cause mortality. Device success was documented in 90.1% of patients. Paravalvular leakage was less than grade II in 98.4% of patients. The mean transvalvular aortic gradient was reduced from 42.5±14.5mmHg at baseline to 7.7±4.0mmHg at discharge (P<.0001 vs baseline). New permanent pacemaker implantation was required in 23.9% of patients. CONCLUSIONS The new generation Evolut R is suitable for most patients and shows high device success and acceptable mortality in an unbiased, consecutive, all-comer population at a single center performing TAVI exclusively with Medtronic valves.

Bispectral index and detection of acute brain injury during cardiac surgery.

EDITOR: Stroke, encephalopathy and cognitive disorders following cardiac surgery remain devastating problems as a result of macroor micro-embolic phenomena or global cerebral hypoperfusion [1]. Besides, more sophisticated neuromonitoring systems (i.e. raw electroencephalogram (EEG), evoked potential, near infra-red spectroscopy), the bispectral index (BIS) derived from a single channel frontal EEG may serve as a simple and less-expensive tool, which affords the unique opportunity to gauge the hypnotic level while detecting cortical dysfunction [2]. Herein, we report a case of severe depression of the BIS index and discuss a multimodal approach for early diagnosis of neurological dysfunction. A 62-yr-old female with an aneurysm of the ascending aorta and stable aortic insufficiency was scheduled for elective valve replacement and aortic prosthetic graft insertion. The patient was chronically treated for diabetes, hyperlipidaemia and hypertension. Four weeks previously, she had suffered a stroke associated with atrial fibrillation. Preoperative cardiac investigations demonstrated normal ventricular function, patent coronary arteries and a 50% stenosis on the left carotid artery with a hypoplastic right vertebral artery. At arrival in the operating room – in addition to standard equipment – a 4-electrodes BIS sensor was placed on the forehead and connected to the AXP-2000 monitoring system (software version 4.0; Aspect Medical, Newton, MA, USA). After intrathecal injection of 0.7 mg morphine, general anaesthesia was induced and maintained with a propofol infusion targeted to BIS values between 40 and 60. After endotracheal intubation and mechanical lung ventilation, transoesophageal echocardiography (TOE) demonstrated the absence of patent foramen ovale and intracardiac thrombi, whereas the ascending aorta appeared free from calcification, atheromatous plaque, intimal flap or false lumen suggestive of dissection. After heparinization, normothermic cardiopulmonary bypass (CPB) was instituted with cannula inserted in the right subclavian artery and the right atrium. After aortic cross-clamping, myocardial protection was accomplished by antegrade infusion of hyperkalaemic blood solution; 2 min later, haemodynamic and blood parameters were unchanged, but the BIS value abruptly decreased from 40 to 0 along with a steep increase in the burst suppression index to 100% (Fig. 1). While any cause of technical artefacts was excluded, the infusion of propofol was slightly decreased and the surgeons were asked to verify the position of the cannulas. Using a transthoracic 4–8 MHz echographic probe at the right temporal acoustic window, colour and pulsed Doppler failed to demonstrate blood flow in the middle and anterior cerebral arteries. While the subclavian arterial cannula was slightly withdrawn, direct puncture of the innominate artery revealed a non-pulsatile pressure value equal to the monitored radial pressure (55–60 mmHg). Although the BIS index persisted at ‘near-zero’ values with the raw EEG resembling a flat line (burst suppression ratio of 100), the surgeons completed the intervention (aortic cross-clamp time of 60 min) by inserting a 24-mm St Jude stentless valve and a 24-mm collagen impregnated Dacron graft. After ventricular de-airing, the patient was weaned from CPB without pharmacological support. Postoperatively, no clinical sign of awakening was noticed and magnetic resonance imaging documented severe and diffuse cortical lesions consistent with anoxic encephalopathy. The patient remained in a persistent coma and active life support was withdrawn on the eleventh postoperative day. Autopsy examination confirmed global brain ischaemic injuries and documented a common origin of right and left carotid arteries. Although BIS index is not designed as a tool for neurological monitoring during cardiac surgery, the sudden and sustained decrease in BIS concurrent with a flat EEG line in our case was highly suspicious for global ischaemic-induced cortical dysfunction at the time of aortic cross-clamping. Among likely causes leading to severe brain damage, one should consider malposition of the subclavian cannula (advanced too proximally) and/ or disruption of atheromatous plaque due to a ‘sandblasting’ effect generated by a high-velocity flow pattern at the orifice of the CPB cannula. Intraoperative TOE and autopsy ruled out arterial Correspondence to: Marc Licker, Service d’Anesthésiologie, Hôpital Universitaire, Rue Micheli-du-Crest, CH-1211 Geneva. E-mail: marc-joseph.licker@ hcuge.ch; Tel: 141 22 3827439; Fax: 141 22 38 27 403

Short-term preoperative exercise therapy does not improve long-term outcome after lung cancer surgery: a randomized controlled study

OBJECTIVES Poor aerobic fitness is a potential modifiable risk factor for long-term survival and quality of life in patients with lung cancer. This randomized trial evaluates the impact of adding rehabilitation (Rehab) with high-intensity interval training (HIIT) before lung cancer surgery to enhance cardiorespiratory fitness and improve long-term postoperative outcome. METHODS Patients with operable lung cancer were randomly assigned to usual care (UC, n  = 77) or to intervention group (Rehab, n  = 74) that entailed HIIT that was implemented only preoperatively. Cardiopulmonary exercise testing (CPET) and pulmonary functional tests (PFTs) including forced vital capacity (FVC), forced expiratory volume (FEV 1 ) and carbon monoxide transfer factor (KCO) were performed before and 1 year after surgery. RESULTS During the preoperative waiting time (median 25 days), Rehab patients participated to a median of 8 HIIT sessions (interquartile [IQ] 25-75%, 7-10). At 1 year follow-up, 91% UC patients and 93% Rehab patients were still alive ( P  = 0.506). Pulmonary functional changes were non-significant and comparable in both groups (FEV 1 mean -7.5%, 95% CI, -3.6 to -12.9 and in KCO mean 5.8% 95% CI 0.8-11.8) Compared with preoperative CPET results, both groups demonstrated similar reduction in peak oxygen uptake (mean -12.2% 95% CI -4.8 to -18.2) and in peak work rate (mean -11.1% 95% CI -4.2 to -17.4). CONCLUSIONS Short-term preoperative rehabilitation with HIIT does not improve pulmonary function and aerobic capacity measured at 1 year after lung cancer resection. TRIAL REGISTRY ClinicalTrials.gov; No. NCT01258478; www.clinicaltrials.gov .

Risk factors of postcardiotomy ventricular dysfunction in moderate-to-high risk patients undergoing open-heart surgery

Introduction: Ventricular dysfunction requiring inotropic support frequently occurs after cardiac surgery, and the associated low cardiac output syndrome largely contributes to postoperative death. We aimed to study the incidence and potential risk factors of postcardiotomy ventricular dysfunction (PCVD) in moderate-to-high risk patients scheduled for open-heart surgery. Methods: Over a 5-year period, we prospectively enrolled 295 consecutive patients undergoing valve replacement for severe aortic stenosis or coronary artery bypass surgery who presented with Bernstein-Parsonnet scores >7. The primary outcome was the occurrence of PCVD as defined by the need for sustained inotropic drug support and by transesophageal echography. The secondary outcomes included in-hospital mortality and the incidence of any major adverse events as well as Intensive Care Unit (ICU) and hospital length of stay. Results: The incidence of PCVD was 28.4%. Patients with PCVD experienced higher in-hospital mortality (12.6% vs. 0.6% in patients without PCVD) with a higher incidence of cardiopulmonary and renal complications as well as a prolonged stay in ICU (median + 2 days). Myocardial infarct occurred more frequently in patients with PCVD than in those without PCVD (19 [30.2%] vs. 12 [7.6%]). By logistic regression analysis, we identified four independent predictors of PCVD: left ventricular ejection fraction <40% (odds ratio [OR] = 6.36; 95% confidence interval [CI], 2.59–15.60), age older than 75 years (OR = 3.35; 95% CI, 1.64–6.81), prolonged aortic clamping time (OR = 3.72; 95% CI, 1.66–8.36), and perioperative bleeding (OR = 2.33; 95% CI, 1.01–5.41). The infusion of glucose-insulin-potassium was associated with lower risk of PCVD (OR = 0.14; 95% CI, 0.06–0.33). Conclusions: This cohort study indicates that age, preoperative ventricular function, myocardial ischemic time, and perioperative bleeding are predictors of PCVD which is associated with poor clinical outcome.