Late Migration of a Transcatheter Heart Valve

Migration or embolization of transcatheter aortic valve replacement (TAVR) prosthesis is an uncommon (usually acute) complication. Associated risk factors include malpositioning, pacing miscapture, undersizing, postdilation, and bicuspid anatomy. Delayed migration is exceedingly rare with little experience reported. The presentation can be catastrophic, requiring emergency surgery. Herein, we present a case of late TAVR migration managed with repeat transfemoral TAVR.

One year prior, he had undergone TAVR at our institution with a 23-mm S3.The postprocedure course was significant for persistent conduction disturbances, which required implantation of a dual chamber pacemaker.The patient did well otherwise.
He was asymptomatic and physical examination was unremarkable.Routine echocardiogram now demon-strated a mean aortic gradient of 27 mm Hg (increased from 7 mm Hg, 1 month after the index procedure).

PAST MEDICAL HISTORY
The past medical history included hypertension, prior transient-ischemic-attack, and coronary artery disease with previous percutaneous transluminal coronary angioplasty to a large diagonal branch.

DIFFERENTIAL DIAGNOSIS
Our main differential diagnoses were hypoattenuated leaflet thickening and early structural valve deterioration.Patient-prosthesis mismatch was felt to be unlikely because the postprocedure gradients had been normal.

FOLLOW-UP
Four months later, the patient remains asymptomatic, with stable position of the valves on fluoroscopy.
Recent echocardiography shows a mitral gradient of 6 mm Hg across the aortic valve without PVL.

DISCUSSION
Migration of TAVR prostheses is a rare complication that typically occurs during the intraprocedural setting or on the first day afterward.[3][4][5][6] Table 1 lists   Alirhayim et al Late Migration of a Transcatheter Heart Valve As an alternative to surgery, some investigators have suggested that a transapical approach in this Alirhayim et al Late Migration of a Transcatheter Heart Valve setting may be safer, 4,5 arguing that the transapical approach can mitigate the risks of retrograde wire crossing of both native and migrated valve with potential further dislocation.Because our patient was hemodynamically stable, we felt that a redo TAVR option through the transfemoral approach was feasible with careful and meticulous technique.We also felt that, with careful planning, a surgical approach could still be performed if redo TAVR failed, with advanced priming of the cardiopulmonary bypass circuit and the presence of a surgical team in the hybrid operating room.
Several procedural aspects warrant mention.First, as an added precaution before advancement of the second THV, we would recommend performing rotational cineangiography to confirm that the guidewire has crossed through the opening of the previously implanted valve and not behind its stent frame.The choice of whether to use a self-expanding or balloon-expandable valve should be informed by computed tomography planning, weighing the risks of landing lower or higher than intended, with resultant aortic regurgitation through the second THV skirt at the aortic annulus level.Although either option may have been possible, we selected a self-expanding valve instead of a balloon-expandable valve (BEV).If we had used another BEV for the redo TAVR, we would have likely selected a second 23-mm S3 to overlap with the first one, which had an average diameter of 21 mm when measured inside the metal frame at the outflow.We were concerned that the intra-annular design of the BEV would pose a challenge, particularly relating to elevated THV gradients after the procedure.We, therefore, selected a self-expanding valve for the redo TAVR with the goal of overlapping with the S3 frame and pinning its leaflets, while allowing us to achieve lower gradients.In patients who are unstable, those with a low surgical risk, or Alirhayim et al Late Migration of a Transcatheter Heart Valve those with significant interaction with the mitral valve leaflets, a surgical approach is likely preferable.

CONCLUSIONS
Delayed TAVR prosthesis migration is an uncommon clinical scenario.Its management is often risky and complex, usually requiring surgery.Redo TAVR is a feasible option in selected cases, subject to careful planning and a thoughtful approach.
His echocardiogram showed normal left ventricular ejection fraction, restricted native aortic valve LEARNING OBJECTIVES To formulate a differential diagnosis in the patient with elevated gradients after TAVR.To understand the technical considerations of redo-TAVR in the stable patient with migrated TAVR prosthesis.opening with a mean gradient of 27 mm Hg, and a more ventricular position of the TAVR prosthesis (Video 1).Review of the index computed tomography angiography (Figures 1A and 1B) showed an annular area of 442 mm 2 , at the margin between 23 and 26 mm when sized for an S3 valve.Given the smaller left ventricular outflow tract (LVOT) dimensions, a 23-mm S3 had been selected.Notably, index imaging had shown only mild leaflet calcification, without LVOT or annular calcification.The initial cine-angiogram (Video 2) demonstrated deployment in a 70/30 position, with 70% of the stent frame in the aortic position and 30% in the LVOT.There had been moderate paravalvular regurgitation (PVL) (Video 3), which immediately resolved after postdilation (Video 4) with an additional 3 mL of volume in the inflation device.Because of the echocardiographic findings (Figure 2A), we proceeded with a repeat computed tomography angiography (Figures 2B to 2G), which revealed complete retrograde migration of the S3 into the LVOT, with its outflow located 1.5 mm below the native aortic annular plane.There was no evidence of hypoattenuated leaflet thickening or structural valve deterioration.MANAGEMENT The patient was reviewed by the multidisciplinary heart team for consideration of surgical explant of the TAVR prosthesis with SAVR, versus redo TAVR.Given the patient's advanced age, lack of significant interaction with the aortic-mitral curtain by the displaced transcatheter heart valve (THV) (mean mitral gradient, 4 mm Hg), and increased surgical risk, a decision was made to proceed with redo TAVR.The goal of the procedure was to treat the native valve AS and to prevent further migration of the original prosthesis.Owing to concerns regarding acute ventricular embolization of the TAVR prosthesis during the procedure, our cardiothoracic surgeons prepared a bail-out surgical plan with a primed cardiopulmonary bypass circuit on pump standby.We crossed the aortic valve with an AL1 diagnostic catheter and a straight guidewire.Proper positioning of the guidewire through the orifice of the THV was confirmed by rotational angiography (Videos 5A and 5B).The AL1 was exchanged for a pigtail catheter through which a curved pre-shaped Circulo 0.035-inch wire (Abbott Vascular) was placed at the LV apex.Balloon predilatation was not performed.A 26-mm Evolut FX valve was overlapped with the frame of the previously implanted S3 (Figures 3A to 3D).5C and 5D).The THV delivery system was withdrawn and partial reversal of heparin was achieved with 20 mg of protamine sulfate.The patient was monitored in the stepdown unit and discharged home the next day.

FIGURE 1
FIGURE 1 CTA Images

FIGURE 2
FIGURE 2 CTA images

FIGURE 2
FIGURE 2 Continued FIGURE 2 Continued

TABLE 1
Factors That May Contribute to Retrograde TAVR TAVR ¼ transcatheter aortic valve replacement.