Clinical application of point of care transthoracic echocardiography in perioperative period

Transthoracic echocardiography (TTE) has established its role for diagnosis and management in cardiology and is used by various other specialities in medicine, but it is not routinely practised by anaesthesiologists in the perioperative period including the pre-admission clinic/outpatient clinic. The last decade has seen the emerging role of anaesthesiologist as a 'Perioperative physician'. This review article highlights the potential role and clinical utility, education, teaching and limitations of point of care (POC) TTE modality in perioperative care. Various echocardiography society guidelines and endorsements, diagnostic protocols and limitations are enumerated. This article also discusses some of the possibilities for future education and development related to clinical ultrasound including POC TTE in anaesthetic training curriculum

Evaluation of latest viscoelastic coagulation assays in the transcatheter aortic valve implantation setting

Background Point of care viscoelastic measures with thromboelastography (TEG; Haemonetics Corporation, Switzerland) and thromboelastometry (ROTEM, Tem Innovations GmbH, Germany) now supersede laboratory assays in the perioperative assessment and management of coagulation. To the best of our knowledge, this sophisticated coagulation assessment has not been performed to characterise thrombotic changes in the transcatheter aortic valve implantation (TAVI) setting, nor have the two latest iteration cartridge-based systems been directly compared in the elective perioperative period.Methods Patients undergoing TAVI were prospectively recruited. Samples (n=44) were obtained at four timepoints (postinduction of anaesthesia, postheparin (100 IU/kg), postprotamine (1 mg/100 IU heparin) and 6 hours postoperatively). Each sample was concurrently assessed with standard laboratory tests (prothrombin time/international normalised ratio, activated partial thromboplastin time, thrombin clotting time, platelet count and direct fibrinogen, ROTEMSigma and TEG6s).Results Clot strength showed a statistically significant increase postheparin/TAVI deployment. When considering the subgroup of samples taken following the administration heparin, the heparinase channel of the TEG6s did not yield clotting strength results in 55% of samples and clotting time exceeded the upper limit of normal in 70% of samples. It was retrospectively recognised that the arachidonic acid channel of the TEG6s Platelet Mapping Cartridge had been decommissioned prohibiting assessment of aspirin effect.Conclusions This study demonstrated a small intraprocedural prothrombotic change of uncertain clinical importance during the transcatheter aortic valve procedure. Further comparison with percutaneous coronary intervention and aortic valve replacement cohorts are needed to assess the merits of current antithrombotic guidelines, which are extrapolated from the PCI setting. The heparin effect was more consistently quantified by ROTEM

Outcomes of the First 300 Cases of Transcatheter Aortic Valve Implantation at a High-Volume Australian Private Hospital

Background: Transcatheter aortic valve implantation (TAVI) was first performed in Australia in 2008 with a steady increase in the number of implanting centres from seven in 2008 to 42 in 2018 (24 private and 18 public hospitals). There is limited published data on outcomes from Australian centres and no published data from Australian private hospitals. We describe outcomes of the first 300 cases at Queensland's first TAVI implanting private hospital. Methods: From July 2015 to August 2018, 300 patients with severe, symptomatic aortic stenosis underwent TAVI at our centre. A heart team assessed all patients as suitable. All patients underwent computed tomography (CT) assessment of valve sizing and peripheral access. Results: Median age was 85 years, 58% male, mean Society of Thoracic Surgeons’ score 4.0%, 49% had New York Heart Association Class III/IV, 28% previous coronary artery bypass grafts, 14% peripheral vascular disease and 3.7% renal impairment (creatinine >177 μmol/L). At 30 days mortality was 1%, stroke 1.3%, myocardial infarction (MI) 0.3%, major vascular complication 3.0%, no life-threatening or disabling bleeding and new permanent pacemaker (PPM) requirement was 9.0%. Paravalvular leak was none, trace and mild in 27%, 53% and 20% respectively with 0.3%≥moderate paravalvular leak. At 1 year, mortality was 4.2%, stroke 2.1%, MI 0.3%, no life-threatening bleeding and PPM 11.4%. Lower rates of mortality, stroke, and major vascular complications were observed compared to the well-established TAVI centres in USA and Germany. Conclusion: Excellent TAVI clinical outcomes can be achieved in the Australian private hospital setting. Expert heart team assessment and CT guided procedural planning are key to these outcomes

Intraoperative Cerebral Perfusion Disturbances During Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement entails profound and unavoidable hemodynamic perturbations that may contribute to the neurological injury associated with the procedure.Thirty-one patients were monitored with cerebral oximetry as a surrogate marker of perfusion while undergoing transcatheter aortic valve replacement via a transfemoral approach under general anesthesia to detect intraoperative hypoperfusion insult. Serial neurologic, cognitive, and cerebral magnetic resonance imaging assessments were administered to objectively quantify perioperative neurologic injury and ascertain any association with significant cerebral oximetry disturbances.Cerebral oximetry reacted promptly to rapid ventricular pacing with significant cerebral desaturation, relative to baseline, of greater than 12% and greater than 20% in 12 of 31 (68%) and 9 of 31 (29%) patients, respectively; or to an absolute measurement of less than 50% in 10 of 31 (33%) patients. Hyperemia occurred immediately following relief of aortic stenosis exceeding baseline by greater than 10% and greater than 20% in 14 of 31 (45%) and 5 of 31 (16%) patients. Postoperative cognitive dysfunction was evident in 3 of 31 (10%) patients and new magnetic resonance imaging-defined ischemic lesions were seen in 17 of 28 (61%) patients. No patient experienced clinically apparent stroke.Cerebral oximetry reacted promptly to rapid ventricular pacing with significant desaturation and hyperemia a common occurrence. However, no association between this intraoperative insult and objective neurologic injury was detected

Radiation exposure of operators performing transesophageal echocardiography during percutaneous structural cardiac interventions

Background: Transesophageal echocardiography operators (TEEOP) provide critical imaging support for percutaneous structural cardiac intervention procedures. They stand close to the patient and the associated scattered radiation. Objectives: This study sought to investigate TEEOP radiation dose during percutaneous structural cardiac intervention. Methods: Key personnel (TEEOP, anesthetist, primary operator [OP1], and secondary operator) wore instantly downloadable personal dosimeters during procedures requiring TEE support. TEEOP effective dose (E) and E per unit Kerma area product (E/KAP) were calculated. E/KAP was compared with C-arm projections. Additional shielding for TEEOP was implemented, and doses were measured for a further 50 procedures. Multivariate linear regression was performed to investigate independent predictors of radiation dose reduction. Results: In the initial 98 procedures, median TEEOP E was 2.62 μSv (interquartile range [IQR]: 0.95 to 4.76 μSv), similar to OP1 E: 1.91 μSv (IQR: 0.48 to 3.81 μSv) (p = 0.101), but significantly higher than secondary operator E: 0.48 μSv (IQR: 0.00 to 1.91 μSv) (p < 0.001) and anesthetist E: 0.48 μSv (IQR: 0.00 to 1.43 μSv) (p < 0.001). Procedures using predominantly right anterior oblique (RAO) and steep RAO projections were associated with high TEEOP E/KAP (p = 0.041). In a further 50 procedures, with additional TEEOP shielding, TEEOP E was reduced by 82% (2.62 μSv [IQR: 0.95 to 4.76] to 0.48 μSv [IQR: 0.00 to 1.43 μSv] [p < 0.001]). Multivariate regression demonstrated shielding, procedure type, and KAP as independent predictors of TEEOP dose. Conclusion: TEE operators are exposed to a radiation dose that is at least as high as that of OP1 during percutaneous cardiac intervention. Doses were higher with procedures using predominantly RAO projections. Radiation doses can be significantly reduced with the use of an additional ceiling-suspended lead shield