Understanding Neurologic Complications Following TAVR

Utility of cerebral oximetry in balloon mitral valvotomy and its correlation with post-procedure neurological complications: A pragmatic prospective observational study

Background and Aims

Neurological complications (NCs) are significantly associated with reduced regional cerebral saturation (rSO₂) in patients undergoing cardiac surgeries, as assessed with cerebral oximetry (COx). However, limited evidence is available in patients undergoing balloon mitral valvotomy (BMV). Thus, we evaluated the utility of COx in patients undergoing BMV, the incidence of BMV-related NCs and the association of >20% reduction in rSO₂ with NCs.

Methods

This pragmatic, prospective, observational study was performed after ethical approval, over November 2018 to August 2020, in the cardiology catherization laboratory of a tertiary care hospital. The study involved 100 adult patients undergoing BMV for symptomatic mitral stenosis. The patients were evaluated at initial presentation, pre-BMV, post-BMV and 3 months after the BMV.

Results

The incidence of NCs was 7%, including transient ischaemic attack (n = 3), slurred speech (n = 2) and hemiparesis (n = 2). A significantly greater proportion of patients with NCs had a > 20% decrease in the rSO₂ (P value = 0.020). At >20% cut-off, the COx had a sensitivity and specificity of 57.1% and 80%, respectively, in the prediction of NCs. Female sex (P value = 0.039), history of cerebrovascular episodes (P value < 0.001) and number of balloon attempts (P value < 0.001) were significantly associated with NCs. Patients with and without NCs had a significantly greater post-BMV mean % change in rSO₂ than pre-BMV (both right and left sides), but the magnitude of mean % change was greater in those with NCs.

Conclusions

COx alone has low sensitivity and specificity in the prediction of NCs and cannot reliably predict the development of post-BMV NCs.

Efficacy of Intraventricular Sponge Placement to Capture Debris in Aortic Valve Replacement

Objective: Surgical aortic valve replacement (SAVR) carries the known risk of shedding debris into the left ventricle during valve leaflet excision and annulus debridement. Embolization of this debris may have devastating effects for the patient. Although surgeons have developed methods to mitigate this risk, no data exist as to their efficacy. Herein, we present the first study that evaluates the efficacy of a technique for capturing debris during SAVR. Methods: Our group conducted a prospective case series of 20 patients who underwent SAVR using the insertion of an intraventricular surgical sponge prior to valve leaflet excision and annulus debridement to capture debris. Surgical sponges were grossly, radiographically, and histologically examined for the presence of cellular and acellular debris to determine the efficacy of this technique. Results: Of the 20 surgical sponges analyzed, 15 specimens (75%) registered positivity for cellular and/or acellular debris. Seven sponges (35%) were grossly positive, 15 sponges (75%) were radiographically positive, and 4 sponges (20%) were histologically positive for calcified debris on examination. Conclusions: This is one of the few studies to objectively evaluate a method used to capture debris in SAVR procedures. Our results demonstrate a high frequency of debris captured within intraventricular surgical sponges and confirms the efficacy of this technique. While these data are promising, numerous additional approaches exist to capture debris, and a best practice standard should exist across the specialty.  In addition, this study does not address the clinical outcomes associated with this technique. To these ends, additional data and multicenter collaboration are required.

Brain Injury After Transcatheter Replacement of Bicuspid Versus Tricuspid Aortic Valves

BACKGROUND

An increasing number of bicuspid aortic valve (BAV) patients are undergoing transcatheter aortic valve replacement (TAVR), but the risk of brain injury in diffusion-weighted magnetic resonance imaging (DW-MRI) is currently unknown.

OBJECTIVES

This study sought to evaluate the risk of brain injury in BAV patients following TAVR.

METHODS

A total of 204 consecutive severe aortic stenosis patients who underwent TAVR were enrolled. A total of 83 (40.7%) patients were BAV patients, and the other 121 patients were tricuspid aortic valve (TAV) patients. All patients received DW-MRI at baseline, and after TAVR.

RESULTS

Median ages (76 years [interquartile range (IQR): 71 to 81 years] vs. 79 years [IQR: 74 to 83 years]; p = 0.004) and Society of Thoracic Surgeons scores (4.87 [IQR: 3.72 to 8.54] vs. 6.38 [IQR: 3.96 to 9.50]; p = 0.044) of the BAV and TAV patients were significantly different, while the overt stroke rates (2.4% vs. 1.7%; p = 0.704) were comparable between the 2 groups. BAV patients were associated with higher number of new lesions (4.0 [IQR: 1.0 to 8.0] vs. 2.0 [IQR: 1.0 to 5.0]; p = 0.008), total lesion volume (290 mm³ [IQR: 70 to 930 mm³] vs. 140 mm³ [IQR: 35 to 480 mm³]; p = 0.008), and the volume per lesion (70.0 mm³ [IQR: 45.0 to 115.0 mm³] vs. 57.5 mm³ [IQR: 24.5 to 93.0 mm³]; p = 0.037) in DW-MRI. Moreover, the proportion of patients with lesions larger than 1 cm³ (28.6% vs. 10.9%; p = 0.005) was higher in BAV patients than in TAV patients.

CONCLUSIONS

BAV patients may encounter more severe brain injuries not only due to greater number of lesions, but also due to larger lesion size in the early phase after TAVR. (Transcatheter Aortic Valve Replacement Single Center Registry in Chinese Population [TORCH]; NCT02803294).

Transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is indicated in some patients with severe aortic stenosis for whom surgical intervention is not deemed appropriate. This article explores when TAVR may be the preferred treatment option over surgical aortic valve replacement and discusses various prosthetic valve devices. The TAVR procedure, diagnostic screenings, complications, postoperative management, and nursing considerations are also outlined.

Neuroprotective measures throughout the TAVI pathway

Aortic stenosis (AS) is the most common clinical valvular heart disorder that warrants active treatment. Symptomatic and severe AS is associated with increased morbidity and mortality if left untouched. Transcatheter aortic valve implantation (TAVI) is an innovative therapeutic modality approved initially for patients with prohibitive surgical risk and subsequently became a mainstream practice and the preferred treatment modality for many patients with severe AS at high and moderate surgical risk. Consistently global TAVI volumes have increased and indications continue to widen toward younger and lower-risk patients. However, periprocedural stroke is one of the most feared complications of TAVI, and when clinically evident, it is often associated with significant increase in mortality, physical disability, social isolation and financial costs. Furthermore, even when clinically overt stroke is not evident following TAVI, highly sensitive imaging modalities have demonstrated new post-procedural ischemic lesions in most patients. Although little is known about the long-term clinical significance of these lesions, there are strong signals showing they might be related with reduced subsequent neurocognitive function. This review provides a comprehensive contemporary insight of the definitions, incidence and temporal trends of stroke in TAVI patients, as well as the mechanisms, etiologies and risk factors for such neurological events. Furthermore, an integrated approach of neuroprotective measures targeted to reduce the incidence of stroke during each phase of the periprocedural TAVI pathway is suggested with a special focus on the role of embolic protective devices.