Scott Beattie

Mild to Moderate Atheromatous Disease of the Thoracic Aorta and New Ischemic Brain Lesions After Conventional Coronary Artery Bypass Graft Surgery

Background and Purpose— The presence of new ischemic brain infarcts, detected by diffusion-weighted magnetic resonance imaging (DW-MRI), have been reported in considerable number of patients after cardiac surgery. We sought to determine the role of proximal thoracic aortic atheroma in predicting embolic events and new ischemic brain lesions in patients undergoing conventional coronary revascularization surgery. Methods— Transesophageal echocardiography and epiaortic scanning was performed to assess the severity of aortic atherosclerosis in the ascending aorta and the aortic arch. Patients were allocated to either low-risk group, (intimal thickness ≤2mm), or high-risk group (intimal thickness >2mm). Transcranial Doppler was used to monitor the middle cerebral artery. DW-MRI was performed 3–7 days after surgery. The NEECHAM Confusion Scale was used for assessment and monitoring patient consciousness level. Results— Patients in the high-risk group were considerably older; 71±6 (n=38) versus 67±6 (n=72) years, P =0.004 and were more likely to have impaired left ventricular function. Confusion was present in 6 (16%) patients in the high-risk group and 5 (7%) patients in the low-risk group. Patients in the high-risk group had a three-fold increase in median embolic count, 223.5 versus 70.0, P =0.0003. DW-MRI detected brain lesions were only present in patients from high-risk group, 61.5 versus 0%, P <0.0001. There was significant correlation between the NEECHAM scores and embolic count in the high-risk group; r=0.63, P <0.001. Conclusions— The findings of this investigation suggest that mild to moderate atheromatous disease of the ascending aorta and the aortic arch (intimal thickness >2mm) is a major contributor to ischemic brain injury after cardiac surgery.

Volatile-based Short-term Sedation in Cardiac Surgical Patients: A Prospective Randomized Controlled Trial

Objective: To evaluate the differences in extubation times in a group of cardiac surgical patients who were anesthetized and sedated with either IV propofol or inhaled volatile anesthetic agents. Design: This was a prospective randomized controlled trial performed between September 2009 and August 2011. Setting: Cardiovascular ICU within a tertiary referral university-affiliated teaching hospital. Patients: One hundred forty-one patients undergoing coronary artery bypass graft surgery with normal or mildly reduced left ventricular systolic function. Intervention: Participants were randomly assigned to receive anesthesia and postoperative sedation using IV propofol (n = 74) or inhaled volatile (isoflurane or sevoflurane) anesthetic agent (n = 67). Measurements and Main Results: Patients sedated using inhaled volatile agent displayed faster readiness to extubation time at 135 minutes (95–200 min) compared with those receiving IV propofol at 215 minutes (150–280 min) (p < 0.001). Extubation times were faster within the volatile group at 182 minutes (140–255 min) in comparison with propofol group at 291 minutes (210–420 min) (p < 0.001). The volatile group showed a higher prevalence of vasodilatation with hypotension and higher cardiac outputs necessitating greater use of vasoconstrictors. There was no difference in postoperative pain scores, opioid consumption, sedation score, ICU or hospital length of stay, or patient mortality. Conclusions: Inhaled volatile anesthesia and sedation facilitates faster extubation times in comparison with IV propofol for patient undergoing coronary artery bypass graft surgery.

Off-pump coronary bypass surgery: risk of ischemic brain lesions in patients with atheromatous thoracic aorta.

PurposeThe purpose of this study was to determine if there is an association between the proximal thoracic aortic (ascending aorta and aortic arch) atheroma and ischemic brain lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) after on-pump (ONCAB) and off-pump (OPCAB) coronary artery bypass surgery.MethodsPatients who underwent ONCAB surgery (n = 13) and who had aortic atheroma > 2 mm were compared to a risk-adjusted prospective cohort of patients (n = 13) undergoing OPCAB surgery. Transesophageal echocardiography and epiaortic scanning were performed to assess the proximal thoracic aorta. Patients were evaluated for new ischemic brain lesions utilizing DW-MRI three to seven days after surgery. The NEECHAM confusion scale was used to evaluate patient consciousness.ResultsThe groups were comparable with respect to demographic data, and prevalence of preoperative risk factors. The extent and severity of aortic atheroma was similar in the two groups. The average maximum height of atheroma was 5.0 ± 2.0 mm in the OPCAB and 4.8 ± 1.9 in the ONCAB groups, respectively. The prevalence of new ischemic brain lesions on DW-MRI was 0% in the OPCAB group and 61 % in the ONCAB group (P = 0.001). Patients in the OPCAB group were less confused during the first two postoperative days.ConclusionPatients with aortic atheroma > 2 mm may have a lower risk of new ischemic brain lesions as identified by DW-MRI after OPCAB surgery. Patient stratification based upon aortic atheroma burden should be addressed in future trials designed to tailor treatment strategies to improve short- and long-term neurological outcomes in patients undergoing cardiac surgery.RésuméObjectifDéterminer s’il y a une association entre l’athérome de l’aorte thoracique proximale (aorte ascendante et crosse de l’aorte) et les lésions cérébrales ischémiques à l’examen d’imagerie par résonance magnétique pondérée par diffusion (IRM-PD) à la suite du pontage aortocoronarien avec circulation extracorporelle (PACCE) et un PAC à cœur battant (PACCB).MéthodeDes patients subissant un PACCE (n = 13) et ayant de l’athérome aortique > 2 mm ont été comparés à une cohorte prospective de patients à risque ajusté (n = 13) subissant un PACCB. L’échocardiographie transœsophagienne et le balayage épiaortique ont permis d’évaluer l’aorte thoracique proximale. La présence de nouvelles lésions cérébrales ischémiques a été vérifiée avec l’IRM-PD trois à sept jours après l’opération. La conscience des patients a été évaluée par l’échelle de confusion NEECHAM.RésultatsLes données démographiques et à la prévalence de facteurs de risque préopératoires intergroupes étaient comparables. L’étendue et la sévérité de l’athérome aortique étaient aussi similaires. La hauteur maximale moyenne de l’athérome était de 5,0 ± 2,0 mm pour le groupe de PACCB et de 4,8 ± 1,9 pour le groupe de PACCE. La prévalence de nouvelles lésions cérébrales ischémiques à l’IRM-PD était de0% avec PACCB et de 61 % avec le PACCE (P = 0,001). Les patients de PACCB étaient moins confus pendant les deux premiers jours postopératoires.ConclusionLes patients avec athérome aortique > 2 mm peuvent présenter un risque plus faible de lésions cérébrales ischémiques comme l’a montré l’IRM-PD après le PACCB. La stratification des patients selon le degré d’athérome aortique devrait être étudiée ultérieurement pour adapter les traitements visant à améliorer les résultats à court et à long terme chez les patients qui subissent une intervention chirurgicale cardiaque.

Can we develop a Canadian Perioperative Anesthesiology Clinical Trials Group

In Canada, research in the field of anesthesiology has been restricted mainly to the domains of basic science and applied physiology. Despite being of valuable scientific relevance and importance, most of this research evaluates physiologic outcomes or surrogate clinical outcomes rather than clinically significant outcomes that could change the way in which we practice. While many medical specialties have appreciated the importance of evaluating outcomes, such as mortality, quality of life, length of stay or efficiency of care, anesthesiology has lagged behind. One of the main reasons Canadian anesthesiology has been slow to embrace outcome studies is the delayed development of a collaborative network of anesthesia investigators to advance multicentre clinical research projects. Clinical research is at a turning point and is rapidly evolving, not only in Canada but worldwide. We strongly believe that Canadian anesthesiologists are capable of markedly improving their research capacity by fostering collaborative outcome-driven research. We further believe that such research can and will change clinical practice. In order to attain this goal, we have initiated a collaborative research network, the Perioperative Anesthesiology Clinical Trials (PACT) group. The PACT group is a collaborative group of Canadian academic anesthesiologists with an interest in the design, implementation, conduct, and publication of multicentre clinical trials in anesthesiology and perioperative medicine. The aim of the PACT initiative is to help anesthesiology clinician investigators 1) to identify and investigate clinically relevant questions in anesthesiology and perioperative medicine; 2) to build research programs that answer their research questions; 3) to structure and conduct quality research with sound methodology; 4) to facilitate collaboration amongst various investigators across Canada so as to conduct multicentre research; 5) to acquire peer-reviewed funding from granting agencies; and finally 6) to execute and publish their results in high-impact peer-reviewed journals. The primary focus of the PACT initiative is to generate knowledge in perioperative anesthesia by providing a forum for the development and implementation of multicentre clinical trials that are designed to answer research questions. It is anticipated that the forum will have a fundamental impact on the practice of anesthesiology and perioperative medicine. In addition, the PACT group will provide mentoring to new investigators as a collaborative network and will facilitate the dissemination of research knowledge, best practices, and standardization of practice parameters, thereby informing the practice of anesthesiology and ensuring its continued advancement as a profession. R. Hall, MD S. Beattie, MD D. Cheng, MD P. Choi, MD A. Y. Denault, MD D. Mazer, MD W. A. C. Mutch, MD A. F. Turgeon, MD H. Yang, MD Perioperative Anesthesiology Clinical Trials Group Steering Committee, Halifax, NS, Canada