Abstract
Mitral valve replacement in the setting of extensive mitral annular calcification is technically challenging and associated with high mortality and morbidity, including stroke. This is the first published report of direct surgical transcatheter valve implantation with use of a cerebral embolic protection device. (Level of Difficulty: Intermediate.)
Key Words: cerebral embolic protection, mitral annular calcification, mitral valve surgery, stroke
Central Illustration
History of Presentation
An 85-year-old woman presented with symptomatic severe mitral regurgitation with severe mitral annular calcification (MAC) and a near porcelain aorta.
Learning Objectives
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To recognize the role for cerebral protection devices in stroke prevention in high-risk surgical patients.
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To understand the strengths and limitations of direct implantation of transcatheter valves in MAC.
Past Medical History
The patient had a medical history of obesity (body mass index: 35 kg/m2), hypertension, hyperlipidemia, chronic kidney disease (glomerular filtration rate: 29 mL/min/1.73 m2), chronic obstructive pulmonary disease, atrial fibrillation, severe calcific stenosis of the infrarenal abdominal aorta, and pulmonary hypertension. Because of uterine cancer, she had undergone hysterectomy and chemotherapy (2019). Additionally, the patient previously experienced cardiac arrest caused by bradycardia, which resulted in pacemaker implantation (2022).
Investigations
Preoperative transesophageal echocardiography (TEE) revealed a left ventricular ejection fraction of 55% and severe mitral regurgitation (MR) (vena contracta: 9.62 mm; posterior-directed jet; reverse systolic flow in the left pulmonary vein); severe MAC encompassing both the anterior and posterior annuli with thickened, calcified leaflets and calcified subvalvular apparatus; and moderate tricuspid regurgitation (TR) (Video 1). Computed tomography confirmed that the degree of MAC precluded a standard mitral valve replacement (MVR) because of the inability and risk of placing the sutures into the calcium. Moreover, the large size of the mitral annulus posed a risk of poor anchoring, valve embolization, and paravalvular leakage (PVL) for transvenous transseptal transcatheter mitral valve replacement. Additionally, a near porcelain aorta was revealed (Figure 1). The patient underwent alcohol septal ablation because of left ventricular outflow tract (LVOT) obstruction (2022) in preparation for possible transcatheter mitral valve replacement but nevertheless remained at risk for LVOT obstruction.
Figure 1.
Computed Tomography Showing Extensive Calcifications
(A) Mitral annulus. (B) Aorta.
Because of the high risk of traditional surgical MVR and anatomic unsuitability for a transcatheter approach, the patient was offered a direct transatrial implantation of a Sapien 3 Ultra (Edwards Lifesciences) into the native mitral valve, avoiding the need for calcium debridement. Given the high risk of calcium embolization because of MAC and near porcelain aorta, the Sentinel Cerebral Protection System (Boston Scientific) was used for cerebral embolic protection (CEP). The study has been approved by the Institutional Review Board (AAAT5941).
Management
A 6-F sheath was placed in the right radial artery, and a pigtail catheter was placed in the aortic root. Median sternotomy was performed, activated clotting time-guided heparinization was instituted (>400s), and both the superior and inferior vena cava were cannulated. Next, the Sentinel was deployed in the innominate artery and the left carotid artery (Video 1) under fluoroscopic guidance. Peripheral cannulation was not possible because of severe stenosis of the infrarenal aorta, so a soft spot was found in the near porcelain ascending aorta, and cannulation was performed.
Bypass was begun, and the patient was cooled (32°C). The aorta was cross-clamped, and cardioplegia was given. The left atrial appendage was ligated with an Atriclip (AtriCure). Because of concern for residual LVOT obstruction, a septal myectomy was performed by making an oblique aortotomy in the aorta and resecting 4 to 7 cm3 of septal muscle tissue.
As expected, inspection of the mitral valve revealed severe MAC throughout the annulus with severe calcium at P2 and P3. A full left-sided cryoablation was performed. A Sapien in MAC was performed as previously described.1
In brief, the anterior leaflet was resected, leaving a 1-cm rim of tissue. The valve orifice opening was sized using the 29-mm Sapien Certitude delivery balloon (Edwards Lifesciences). The prosthesis was prepared on the back table by sewing a felt skirt to the frame at the base (atrial side) and later crimped. Concurrently, sutures were placed circumferentially through the anterior and posterior mitral leaflet tissue with pledgets on the atrial side. The Sapien 3 Ultra Resilia valve system was then directly introduced into the left atrium and through the mitral valve orifice over a soft J-wire, positioned, and deployed. All anchoring sutures were placed through the valve frame and tied down. The valve was postdilated with the same balloon volume.
The atriotomy was closed, heart de-aired, aortic clamp released, and rhythm restored. TEE subsequently revealed a severe PVL posteriorly (P2 adjacent to the large immobile calcium bar, forming a crevice) that required re-arresting the heart and exposing the valve again. A felt patch was fashioned and sewn to the left atrial wall and the valve frame, closing the defect. The surgical closing resumed, and no further PVL/MR was observed in TEE.
The Sentinel was removed, showing extensive calcium debris captured in both the proximal and distal filter (Figure 2). The patient was successfully weaned from bypass and decannulated, and hemostasis was achieved (cardiopulmonary bypass: 262 min; cross clamp: 176 min). Because of hypotension and high ventilatory pressures, a delayed chest closure was conducted 4 days later.
Figure 2.
Visible Calcium Debris Captured by Cerebral Embolic Protection Device
Discussion
Mitral annular calcification is a chronic degenerative process of the mitral annulus that can affect the leaflets and surrounding myocardium, leading to valve dysfunction. Its prevalence is 8% to 15%, increasing with age and other cardiovascular risk factors.2 MAC is associated with increased risk of mortality and stroke.3 The presence of extensive calcifications makes surgery challenging, greatly increasing the perioperative mortality and morbidity as well as diminishing the technical success rate of mitral valve surgery.2
The surgical implantation of transcatheter valve-in-mitral annular calcification (ViMAC) has emerged as an alternative to both surgical and transcatheter MVR, especially in patients deemed at prohibitive anatomic risk of LVOT obstruction.4 Although the technique significantly reduced mortality and achieved high technical success, the rate of complications remained high when compared to non-MAC interventions (30-day risk of stroke: 3.9%).5, 6, 7 This situation is compounded by concomitant conditions strongly associated with MAC, such as porcelain aorta, that further increase the risk of stroke.7
To the best of our knowledge, the use of cerebral embolic protection has not been reported previously in ViMAC or other high-risk cardiac surgery. The Sentinel has been investigated as an adjunct device to capture embolic debris and decrease the risk of cerebral embolic injury during transcatheter aortic valve replacement (TAVR). Several studies have demonstrated that the device is safe and effective at capturing debris during TAVR,8 and although the recent PROTECTED TAVR (Stroke PROTECTion With SEntinel During Transcatheter Aortic Valve Replacement) trial failed to prove a significant reduction in perioperative stroke, it did suggest a reduction in the incidence of disabling stroke.9 Because of the high embolic risk of surgery with MAC and other high-risk cardiac surgery, we believe that these patients might benefit from the use of a CEP filter. In the current case, the Sentinel was able to capture a large volume of debris that would have potentially embolized cerebral arteries, causing stroke. Despite the high risk of surgery and the extensive calcifications, no neurologic deficits or Sentinel-related complications were reported in this patient, suggesting that the filter was safe and effective in providing cerebral embolic protection.
Follow-Up
TTE the following day showed a stable bioprosthesis position with no PVL/MR (Video 1). Sedation was weaned, and the patient was fully awakened on postoperative day (POD) 1. No neurologic deficit was observed. The postoperative course was complicated by acute kidney injury requiring renal replacement therapy (POD5), cardiogenic shock requiring inotrope support, pneumonia, sternal wound infection, and respiratory failure requiring tracheostomy (POD13). The patient remained interactive and conversive both before and after tracheostomy, and no signs of neurologic injury were present. Neurologic imaging was not performed because there was no clinical concern for neurologic injury. The patient’s clinical condition gradually deteriorated, and the patient was eventually moved to comfort care and died (POD64).
Conclusions
This is a novel clinical report presenting the feasibility of use of a commercially available CEP device during ViMAC. In cases with significant MAC or other high-risk features, the use of cerebral filters may reduce the risk of periprocedural stroke. Further research is required to demonstrate the safety and efficacy of CEP devices in capturing embolic debris and reducing stroke risk in cardiac surgery.
Funding Support and Author Disclosures
Dr George has served as a consultant (honoraria) for Zimmer Biomet, Atricure, Neosurgery, Neptune Medical, AbbVie, Johnson & Johnson, Boston Scientific, Edwards Lifesciences, Medtronic, Help-TheraX, 3ive, Encompass, Summus Medical, Abbott SJM, Encompass Medical, BCI, and NeeToor Cardio; as served on advisory boards for Edwards Surgical, Medtronic Surgical, Medtronic Structural Mitral & Tricuspid, Trisol Medical, AbbVie, Johnson & Johnson, Foldax Medical, Zimmer Biomet, Neosurgery, Boston Scientific, Summus Medical, BCI, and NeeToor Cardio; holds equity in Valcare Medical, Durvena, CardioMech, Vdyne, MitreMedical, and MITRx; and has received institutional funding to Columbia University from Edwards Lifesciences, Medtronic, Abbott Vascular, Boston Scientific, and JenaValve. Dr Nazif has served as a consultant (honoraria) for Medtronic, Boston Scientific, EnCompass Medical, and Teleflex. Dr Kachel has reported that he has no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
Appendix
For a supplemental video, please see the online version of this paper.
Appendix
Preoperative Echocardiography, Cerebral Embolic Protection Device Insertion, MAC: Surgical View, Postoperative Echocardiography
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Supplementary Materials
Preoperative Echocardiography, Cerebral Embolic Protection Device Insertion, MAC: Surgical View, Postoperative Echocardiography