Early Experience With Embolic Protection Devices During Transcatheter Aortic Valve Replacement

Abstract: Objectives. Embolic protection devices (EPDs) have been employed to combat the risk of cerebrovascular events during transcatheter aortic valve replacement (TAVR). The use of EPD has been shown in some studies to decrease periprocedural stroke incidence when compared with non-EPD TAVR. Our study aimed to compare the postoperative outcomes of TAVR with versus without EPD. Methods. Thirty-three patients who underwent TAVR with EPD at our institution between October 2018 and February 2019 were compared with a contemporaneous control group of 50 patients who underwent TAVR during the same time period without EPD. Baseline characteristics, operative characteristics, and postoperative outcomes were compared between groups. Exclusion criteria for utilization of EPD included arch vessel tortuosity, calcified arch branches, and size discrepancy between the device and host arteries. Results. The non-EPD group had a higher Society of Thoracic Surgeons risk score (6.8% vs 3.3% in the EPD group; P<.01) and more frequently had a prior diagnosis of diabetes mellitus (52% vs 21% in EPD patients; P<.01). Intraoperative characteristics were comparable, without significant differences in access site used, valve type (Sapien 3 vs Evolut), utilization of rapid pacing, or utilization of balloon aortic valvuloplasty. Conclusion. EPD was used in lower-risk patients, possibly related to lower incidence of vessel calcification in those patients that may preclude EPD use. Although postoperative outcomes between groups were comparable, current EPD design use precludes its utilization in higher-risk patients.

J INVASIVE CARDIOL 2019;31(10):296-299.

Key words: embolic protection, outcomes, stroke, transcatheter valves

Transcatheter aortic valve replacement (TAVR) is an important intervention indicated for intermediate-risk and high-risk patients with severe aortic stenosis that are poor candidates for conventional surgical valve replacement.^1-3 Stroke is a particularly feared complication of TAVR, with most periprocedural cerebrovascular events occurring due to debris embolization during the procedure.^4,5 Despite decreasing rates compared with early TAVR experience, stroke remains one of the most devastating complications, associated with increased morbidity and mortality.- In addition, clinically silent cerebral injury, occurring in a large majority of patients, may be associated with a decline in neurocognitive function.^4-9

Cerebral embolic protection devices (EPDs) have been employed during TAVR to combat the risk of cerebrovascular events by capturing or deflecting embolic debris during the procedure, with encouraging results.^10-12 EPDs have been reported to collect embolic debris in up to 99% of patients, especially those treated with balloon-expandable valves.^7,13,14 The potential protective effect that EPDs confer on neurocognitive function related to silent ischemic injury remains unclear.^5,7,10,15-17

The aim of our study was to evaluate the indications and exclusion criteria for EPDs, and to compare postoperative outcomes of TAVR with versus without EPD.

Methods

Study design and conduct. This is a retrospective study of consecutive patients undergoing TAVR at JFK Medical Center between October 2018 and February 2019. All patients who underwent TAVR with utilization of EPD at our institution (n = 33) were compared with a contemporaneous control group who underwent TAVR without the use of EPD (n = 50). Data were obtained by a coordinating center and prospectively entered into a database. Exclusion criteria for EPD included arch vessel tortuosity, calcified arch branches, and size discrepancy between the device and host arteries. The Western Institutional Review Board granted study approval and protected health information remained confidential, as required by 1996 Health Insurance Portability and Accountability Act regulations.

The Society of Thoracic Surgeons (STS) National Database definitions were used for this study. Diabetes was defined as a history of either type 1 or type 2 diabetes mellitus, regardless of duration of disease or need for oral agents or insulin. Prolonged ventilation was defined as pulmonary insufficiency requiring ventilatory support for >24 hours postoperatively. Postoperative stroke was defined as any new major neurologic deficit, lasting for >24 hours and confirmed by either computed tomography (CT) or magnetic resonance imaging (MRI). Operative mortality included all deaths occurring within 30 days of the procedure, as well as all deaths during index hospitalization, regardless of time from procedure.

Data analysis. Categorical data are presented using number (percentage), while continuous variables are presented using median (interquartile range [IQR]). Differences in preoperative and operative characteristics, as well as postoperative outcomes, were analyzed between groups using Fisher’s exact test for categorical variables and Wilcoxon rank-sum test for continuous variables. All tests were two-sided and P-value <.05 was considered statistically significant. All statistical analyses were performed using SAS statistical software, version 9.4 (SAS Institute).

Results

Preoperative characteristics between patients undergoing TAVR with EPD vs without EPD were comparable (Table 1). A higher proportion of patients in the non-EPD group had a history of prior myocardial infarction (24% vs 9%), peripheral artery disease (28% vs 18%), and carotid stenosis (24% vs 12%), although none of these differences were statistically significant. More patients in the non-EPD group had a prior diagnosis of diabetes mellitus (52% vs 21%; P<.01). The non-EPD group had higher STS scores than the EPD group (6.8% vs 3.3%, respectively; P<.01).¹⁸

Intraoperative characteristics are summarized in Table 2. No significant differences were found in access site used, with the predominant access being transfemoral in both groups (94% in the non-EPD group vs 88% in the EPD group). The Sapien 3 valve (Edwards Lifesciences) was used in approximately 75% of patients in both groups, with the Evolut valve (Medtronic) used in the remainder.

Postoperative outcomes are shown in Table 3. The non-EPD group had higher vascular complication rates compared with the EPD group, which experienced no such complications (12% vs 0%, respectively; P=.08). Although the non-EPD group had a higher 30-day readmission rate, this difference was not statistically significant (22% vs 6% in the EPD group; P=.07).

Two patients (4%) in the non-EPD group and 1 patient (3%) in the EPD group had a perioperative stroke. Review of preoperative and postoperative MRI findings revealed that the 2 non-EPD patients had strokes that involved multiple locations in both hemispheres and were larger in volume, while the stroke in the EPD patient was single, unilateral, more localized, and smaller in volume; the EPD stroke occurred in a left transcarotid TAVR patient who had calcification of the innominate artery and underwent insertion of a single innominate artery basket. Postoperatively, the patient developed stroke at the EPD site, probably related to dislodgment of debris during wire manipulation for placement of the device.

Discussion

With expanding indications for TAVR in lower-risk patients, it is necessary to reduce complications — particularly stroke, which is catastrophic to both the patient and the health-care system. Some studies have shown promising findings and decreased risk of periprocedural stroke, a higher rate of stroke-free survival, and a mortality benefit with the use of EPDs.^11,12 EPDs have been reported to collect embolic debris (Figure 1) in up to 99% of patients.^7,13,14 While several studies indicate that clinically silent ischemic injury is reduced in TAVR with vs without EPDs, others have found no significant difference.^7,9,10,19-21 In this preliminary study, we compared the postoperative outcomes for TAVR with vs without EPDs.

EPD in lower-risk patients. In our study, EPDs appeared to be used in lower-risk patients based on STS risk score. The median STS risk score was 3.3% in patients with EPD and 6.8% in patients without EPD (P<.01); these results are similar to previous studies.^18,22,23 Furthermore, the non-EPD group had higher rates of peripheral artery disease and carotid stenosis than the EPD group, indicating a higher incidence of arch vessel calcification, which may preclude EPD insertion. One of the 33 EPD patients experienced stroke. This patient underwent TAVR via a left transcarotid approach with an EPD placed only in the innominate artery. The patient suffered a right-sided stroke, which was likely related to tortuosity and calcification of the innominate artery that resulted in debris embolization prior to deploying the EPD. The risk of stroke following TAVR in our population was 4% in those without EPD and 3% in those with EPD, which is consistent with a previously reported 30-day risk of stroke of 2%-5%.²⁴

Postoperative outcomes. Vascular complication risk was lower in the EPD group (0% vs 12% in the non-EPD group; P=.08), which was probably related to lower incidence of peripheral vascular disease. Use of EPD was associated with a reduced 30-day readmission rate (6% vs 22% in the non-EPD group; P=.07), which was possibly related to the lower risk profile of EPD patients.

Regional distribution of stroke. Two non-EPD TAVR patients in our study suffered multiple, bilateral, and larger-volume strokes compared with a single localized stroke in the right frontal subcortical region in 1 EPD TAVR patient. In the MISTRAL-C trial, MRI performed 1 day before as well as 5-7 days after TAVR showed increase in the overall number of infarcts as well as total lesion volume in the non-EPD cohort compared with the EPD cohort (P=.07 and P=.06, respectively), which is consistent with our findings.¹⁸ Similar findings were noted in a meta-analysis by Bagur et al, in which the use of EPD was associated with significantly less ischemic volume per lesion (P<.01) and less total volume of lesions (P=.02).²⁰

Clinical implications. This study analyzed a real-world population of patients who received TAVR with and without EPDs. In our study, insertion of EPD was only feasible in lower-risk patients without significant peripheral vascular disease and thus questions the expansion of the current Food and Drug Administration (FDA)-approved devices in higher-risk patients. The stroke complicating 1 EPD patient was single and isolated as compared with the multiple strokes that occurred in 2 non-EPD patients.

Study limitations. Limitations of this study include the bias inherent in the retrospective, single institution methodology. Another limitation is the small sample size, due to the recent introduction of EPD in our institution; this recent introduction also precluded long-term follow-up in this analysis. Furthermore, neurocognitive testing was beyond the scope of our study.

Conclusion

In the early adoption period that was studied, EPDs appeared to be used in lower-risk patients based on STS risk score; this was potentially attributable to increased vessel calcification in higher-risk patients, which precludes EPD placement. However, this preliminary study indicates promising results regarding the safety of EPDs, with comparable postoperative outcomes to TAVRs without EPD. Future studies and better EPD designs in the next generation of devices are required to allow the expansion and universal use of EPDs in TAVR patients.

References

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From the ¹JFK Medical Center, Atlantis, Florida; and ²University of Miami, Miller School of Medicine, Miami, Florida.

Funding: This research was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted May 19, 2019, accepted May 29, 2019.

Address for correspondence: Sotiris C. Stamou, MD, PhD, JFK Medical Center, 180 JFK Drive, Suite 320, Atlantis, FL 33462. Email: sotiris.stamou@hcahealthcare.com