Influence of continuously evolving transcatheter aortic valve implantation technology on cerebral oxygenation

Cerebral regional oxygen saturation as a predictive parameter for preoperative heart failure and delayed hemodynamic recovery in transcutaneous aortic valve implantation: a retrospective cohort study

This study aimed to investigate the relationship of perioperative cerebral regional oxygen saturation (rSO2) with various preoperative clinical variables and hemodynamic changes during transfemoral transcatheter aortic valve implantation (TAVI) under general anesthesia. We retrospectively analyzed cerebral rSO2 values from left-hemisphere measurements obtained using near-infrared spectroscopy (O3™ regional oximetry) at five time points: pre-induction, the start of the procedure, the start of valve deployment, time of lowest cerebral rSO2 value during valve deployment, and the end of the procedure. This study included 91 patients (60 with balloon-expandable valves and 31 with self-expandable valves). The baseline cerebral rSO2 values were correlated with B-type natriuretic peptide, hemoglobin, fractional shortening, ejection fraction, left ventricular mass index, left ventricular end-systolic diameter, STS risk of mortality, and STS morbidity or mortality. The patients who took longer to recover their systolic blood pressure to 90 mmHg after valve deployment with a balloon-expandable valve (group B) had lower cerebral rSO2 values during deployment compared to patients with faster recovery with balloon-expandable valve (group A) and with self-expandable valve (group C). Baseline cerebral rSO2 is associated with preoperative variables related to cardiac failure and function, and a significant decline during valve deployment may indicate a risk of prolonged hypotension during TAVI.

Cerebral Tissue Oxygen Saturation Is Enhanced in Patients following Transcatheter Aortic Valve Implantation: A Retrospective Study

Transcatheter aortic valve implantation (TAVI) has emerged as an alternative to surgical aortic valve replacement. The aim of this study was to evaluate whether a relevant alteration in cerebral tissue oxygen saturation (rSO2) could be detected following TAVI. Retrospective data analysis included 275 patients undergoing TAVI between October 2016 and December 2020. Overall, rSO2 significantly increased following TAVI (64.6 ± 10% vs. 68.1 ± 10%, p < 0.01). However, a significant rise was only observed in patients with a preoperative rSO2 < 60%. Of the hemodynamic confounders studied, hemoglobin, mean arterial pressure and blood pH were lowered, while central venous pressure and arterial partial pressure of carbon dioxide (PaCO2) were slightly elevated (PaCO2: 39 (36−43) mmHg vs. 42 (37−47) mmHg, p = 0.03; pH: 7.41 (7.3−7.4) vs. 7.36 (7.3−7.4), p < 0.01). Multivariate linear regression modeling identified only hemoglobin as a predictor of altered rSO2. Patients with a EuroScore II above 4% and an extended ICU stay were found to have lower rSO2, while no difference was observed in patients with postoperative delirium or between the implanted valve types. Further prospective studies that eliminate differences in potential confounding variables are necessary to confirm the rise in rSO2. Future research should provide more information on the value of cerebral oximetry for identifying high-risk patients who will require further clinical interventions in the setting of the TAVI procedure.

Intraoperative hypotension and delirium among older adults undergoing transcatheter aortic valve replacement

Background

Postoperative delirium (POD) is a frequently observed complication after transcatheter aortic valve replacement (TAVR). The effects of intraoperative hypotension (IOH) on POD occurrence are currently unclear.

Methods

A retrospective observational cohort study of patients who underwent TAVR was conducted. We predefined IOH as area under the threshold (AUT) of five mean arterial blood pressures (MBP), varying from <100 to <60 mmHg. The AUT consisted of the combination of duration and depth under the MBP thresholds, expressed in mmHg*min. All MBP AUTs were computed based on the complete procedure, independent of procedural phase or duration.

Results

This cohort included 675 patients who underwent TAVR under general anesthesia (n = 128, 19%) or procedural sedation (n = 547, 81%). Delirium occurred mostly during the first 2 days after TAVR, and was observed in n = 93 (14%) cases. Furthermore, 674, 672, 663, 630, and 518 patients had at least 1 min intraoperative MBP <100, <90, <80, <70, and <60 mmHg, respectively. Patients who developed POD had higher AUT based on all five MBP thresholds during TAVR. The penalized adjusted odds ratio varied between 1.08 (99% confidence interval [CI] 0.74–1.56) for the AUT based on MBP < 100 mmHg and OR 1.06 (99% CI 0.88–1.28) for the AUT based on MBP < 60 mmHg.

Conclusions

Intraoperative hypotension is frequently observed during TAVR, but not independently associated with POD after TAVR. Other potential factors than intraoperative hypotension may explain the occurrence of delirium after TAVR.

Effects of a dual-filter-based cerebral embolic protection device in transcatheter aortic valve replacement on cerebral oxygen saturation: A prospective pilot study

PURPOSE

The Sentinel Cerebral Protection System (Sentinel-CPS) is increasingly used in transcatheter aortic valve replacement (TAVR). However, the impact of inserting the Sentinel-CPS inside the brain-supplying arteries on cerebral perfusion and oxygenation is unknown.

METHODS

Twenty patients undergoing transfemoral TAVR with (n = 10) and without (n = 10) cerebral embolic protection using the Sentinel-CPS were prospectively observed. All patients received conscious sedation and cerebral oxygen saturation (rSO₂ ) was continuously measured with near-infrared spectroscopy (NIRS). The cumulative perioperative cerebral desaturation was calculated for each patient by multiplying rSO₂ below an individualized desaturation threshold by time. In addition, rSO₂ values at the time of Sentinel-CPS insertion, filter positioning, and device retraction were analyzed.

RESULTS

There was no significant difference in cumulative cerebral desaturation in patients with Sentinel-CPS (median [IQR]) (0 [0/81] s%) and without (median [IQR]) (0 [0/23] s%), p = .762. A total of 6 patients (33.3%) experienced a perioperative decrease in rSO₂ below the individualized desaturation threshold (n = 3 with Sentinel-CPS, n = 3 without Sentinel-CPS; p = 1.000). Cerebral desaturation was detected during valve deployment (n = 5) and after postdilatation (n = 1). No desaturation events occurred during Sentinel-CPS insertion, filter positioning, or retraction.

CONCLUSION

Our pilot study revealed no difference in cumulative perioperative cerebral desaturation between TAVR with and without Sentinel-CPS. Catheter- and filter-based manipulations in the brain-supplying arteries for Sentinel-CPS application were not associated with a decrease of cerebral perfusion and oxygenation.

Effect of Transcatheter Aortic Valve Replacement on Retinal Layer Thickness Measured by Optical Coherence Tomography

Transcatheter aortic valve replacement (TAVR) is associated with clinically significant cerebral microembolism and cognitive status changes. There are no data on the impact of TAVR on retinal layers. We assessed the influence of TAVR on the retinal nerve fiber layer, ganglion cell complex (GCC), and macular thickness (MT) measured by spectral domain optical coherence tomography (SD-OCT). Elderly patients (n = 50) with severe aortic stenosis undergoing TAVR were included in this study (mean age: 78.5 ± 6.9 years). Retinal nerve fiber layer, GCC, and MT were measured with SD-OCT by an ophthalmologist before and on the first day and in the first month after TAVR. The average MT was significantly increased on the first day after TAVR compared with the basal value (P = .04). Ganglion cell complex thickness was significantly thinner on the first day after TAVR than the basal value in the inner inferior quadrant and outer temporal quadrant of the left eye (P = .03 and .04, respectively). Postoperative changes observed on the first day compared with the preoperative period returned to basal values in the first month. In conclusion, TAVR did not cause permanent changes in retinal layers.