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.

Percutaneous Transvenous Mitral Valve-in-Valve Implantation Using Commercially Available Transcatheter Valve. First Australian Experience.

In patients with a degenerative mitral bioprosthesis and prohibitive surgical risk there is emerging evidence for the feasibility of valve-in-valve procedures via a percutaneous transvenous transseptal approach. This paper describes the first time this procedure has been performed in Australia.

Hemostatic Profiles of Patients Who Underwent Transcatheter Versus Surgical Aortic Valve Replacement Versus Percutaneous Coronary Intervention.

Guidelines for transcatheter aortic valve replacement (TAVR) antithrombotic prophylaxis are extrapolated predominantly from percutaneous coronary intervention (PCI) data. Here, we examined temporal coagulation changes occurring in the early perioperative period to determine the pathobiologic validity of this supposition. This was a prospective observational study of consecutive patients who underwent transfemoral TAVR (n = 27), PCI (n = 12), or surgical aortic valve replacement (SAVR) requiring cardiopulmonary bypass and cross-clamping (n = 12). Blood samples were taken at 4 time points: T1 (baseline), after general anesthesia or sedation; T2, after heparin administration; T3, at the end of the procedure; and T4, 6 hours after the procedure. The samples were assessed concurrently using standard laboratory coagulation tests and viscoelastic tests of whole blood clotting, including the latest generation thromboelastometry (ROTEM sigma) and thromboelastometry (TEG 6s). Patients in the TAVR cohort were older and a had lower baseline hemoglobin level than patients in the PCI and SAVR cohorts. The baseline platelet function was similar between the TAVR and PCI cohorts and impaired in the SAVR cohort Figure S1. The baseline hemostatic measures were comparable among cohorts. Regarding the per-patient change from baseline, the TAVR cohort showed an overall more prothrombotic state than the other cohorts, with the most marked differences from the SAVR cohort after intraoperative heparin administration and from the PCI cohorts 6 hours after the procedure. In addition, the ROTEM and TEG parameters were well correlated but not interchangeable. In conclusion, patients who underwent TAVR have a more prothrombotic hemostatic profile than PCI and SAVR patients. These findings question the current guidelines that extrapolate antithrombotic regimens from PCI to TAVR settings.

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.

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.

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.

Intraoperative Cerebral Perfusion Disturbances During Transcatheter Aortic Valve Replacement.

BACKGROUND: Transcatheter aortic valve replacement entails profound and unavoidable hemodynamic perturbations that may contribute to the neurological injury associated with the procedure. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.