Transcatheter “Sandwich” Valve-in-Valve Implantation Technique for Pure Aortic Regurgitation: Operation Skills and Early Experience

Abstract

No commercial “on-label” transfemoral transcatheter aortic valve replacement (TAVR) device for aortic regurgitation (AR) is available in most countries. TAVR for AR with an “off-label” self-expanding device has shown acceptable procedural success but it elevated rates of early mortality and other complications. Valve disposition or displacement frequently occurs during transfemoral TAVR (TF-TAVR) for AR with a self-expanding valve, because of weak anchoring force. To overcome this problem, we propose a transcatheter “sandwich” valve-in-valve implantation (SVIV) technique, which has achieved good results. Our initial results and experience in a case series comprising seven patients suggest that the SVIV technique using commercially available self-expanding valves may be an option for treating selected patients with AR with high risk for surgical valve replacement. Compared with the traditional method, this technique can decrease the incidence of complications, particularly conduction block, but several technical details require the operator’s attention. Additional research is required to confirm the superiority of this technology.

Main article text

Transcatheter aortic valve replacement (TAVR), a safe and effective minimally invasive therapy, has become a first-line treatment for older patients with aortic stenosis (AS) [1, 2]. TAVR was initially applied to treat AS, and its use gradually expanded to aortic regurgitation (AR) treatment. Transapical TAVR (TA-TAVR) devices have been found to be safe and effective in treating patients with AR with high surgical risk [3, 4]. However, transfemoral TAVR (TF-TAVR) has been associated with less trauma, greater safety, and lower incidence of death and complications than TA-TAVR, and thus has become the preferred method [5, 6]. However, no “on-label” transfemoral TAVR device is currently commercially available in most countries, including China and the USA, and most transfemoral TAVR devices remains in clinical trials [7, 8]. TAVR for AR with an “off-label” self-expanding device is associated with acceptable procedural success, but elevated rates of early mortality and other complications [9–13]. Valve disposition or displacement frequently occurs during TF-TAVR for AR with a self-expanding valve, because of weak anchoring force; this complication is among the most important and common for TAVR in patients with AR [9, 12, 13]. To overcome this problem, we propose the transcatheter “sandwich” valve-in-valve implantation (SVIV) technique [14], which has achieved good results. This article introduces the surgical techniques of this method and describes our relevant experience.

Technical Principles and Advantages

The technical principle of SVIV is that the first and second valves are securely attached and connected to form an overall structure that clamps the native leaflets; the native leaflets firmly drag the overall structures of the two valves, thereby preventing upward valve movement. The first prosthesis is placed at the bottom of the Valsalva sinus, thus preventing downward movement of the two valves. The first valve, native leaflets, and second valve form a sandwich structure, after which the technique is named. Valves placed with this technique should be more stable than those placed with a traditional valve-in-valve technique. With the traditional technique, the first valve is placed in the outflow tract, and the two valves can move down because of insufficient radial support of the native aortic valve and its surrounding anatomy for the valve stents, even when two valves are used. Conduction abnormalities, particularly permanent pacemaker implantation risk, might be lower with this technique compared to traditional valve-in valve technique, because the valves can be placed in a higher position of the left ventricular outflow tract.

The SVIV technique uses only self-expanding valves, particularly retrievable valves. However, we believe that using a self-expanding valve as the first valve and a balloon valve as the second valve might be also feasible. The SVIV technique can serve as a bail-out remedy if the first valve is placed too high and jumping up to the ascending aorta (we call this method the passive SVIV technique), and can also be performed as a pre-planned procedure, in which the first valve is directly released in the ascending aorta (we call this method the active SVIV technique). However, for use of the latter technique, patients should be well evaluated. The aortic annulus should not be too large to prevent paravalvular leak (perimeter <95 mm); the risks of coronary and aortic dissection should be low; and the patient should be at high risk of, or contraindicated for, surgical valve replacement, and should have a large annulus.

Operation Skills and Process

First, the first valve is implanted in the ascending aorta through a passive or active method (Figure 1A). A super-stiff wire (preferably an extra stiff wire, such as a Lunderquist wire) is placed into the femoral accessory 6 F pigtail catheter to enhance the catheter support force. The operator then places the end of the pigtail catheter and the stiff wire in the sinus or the crown of the prosthesis, then pushes the first prosthesis forward and allows it to sit at the bottom of the Valsalva sinus (Figure 1B). The end of the extra stiff wire must be shaped into a large circle to create a driving force on the crown or sinus of the valve stent without sliding toward the left ventricle from between the prosthesis leaflets. This step is the primary challenge and is key to the entire procedure; thus, the lower end of the first valve stent must reach the native aortic sinus. However, the stent need not be inserted into all three sinus bottoms – only one sinus bottom is acceptable. Another 6 F pigtail catheter is advanced through the radial artery or other routes used for aortic root angiography. A second prosthesis is placed through a valve-in-valve procedure and released 2–4 mm below the native annulus (Figure 1C). The size of the second valve is consistent with that of the first valve. The second valve should be released rapidly and allowed to quickly fix the first valve, but it must not move past a retrievable position during the release process. The first valve should be firmly pushed on the sinus bottom and should not move upward (Video 1). Transesophageal echocardiography can be used to confirm the above procedure and whether both valves have clamped onto the native valve. If this situation is not achieved, the second valve should be retrieved and not released. The distance between the lower end of the first valve and the second valve should not exceed 8 mm; otherwise, their fixation force may be insufficient and may cause mutual movement after release of the second valve. The pigtail catheter for angiography may be sandwiched between the valve stents, in which case it cannot be forcefully pulled out; otherwise, valve displacement might occur. One wire should be inserted from the pigtail catheter and pushed, and the reaction force should be used to make the pigtail catheter quickly get out of the valve stents. Subsequently, the wire is slowly pulled out by the operator. Finally, an angiography is performed to verify the results (Figure 1D).

Figure 1

Case Demonstration of the SVIV Technique [14].

A. A 30-mm self-expanding valve was released in the ascending aorta. B. The valve was pushed to the bottom of the Valsalva sinus with a super-stiff wire and 6 F pigtail catheter. C. The second valve was released valve-in-valve approximately 2 mm below the native annulus. D. The first valve, native leaflets, and second valve formed a “sandwich” structure.

Attention must be paid to the potential risks of this technique: (1) The native annulus should not be too large (e.g., perimeter >95 mm), to avoid the risk of the first valve shifting to left ventricular and perivalvular leakage. (2) The risk of coronary obstruction should be excluded through detailed evaluation of preoperative computer tomography (CT). The sinutubular junction (e.g., diameter >30 mm) and sinus should be sufficiently large. (3) In addition, a potential risk of aortic dissection exists with this technique. After the release of the first valve, the valve should be immediately pushed to the bottom of the sinus to prevent the valve from moving back and forth and damaging the ascending aorta. The risk of leaflet thrombosis may increase with valve-in-valve implantation.

Case Series Results

We collected data from seven patients who underwent SVIS procedures at Zhongshan Hospital Fudan University (five cases), the First Affiliated Hospital of Nanchang University (one case), and the First Affiliated Hospital of Zhejiang University (one case) between October 2022 and June 2023. All patients had pure severe AR, a high Society of Thoracic Surgery (STS) score, age above 60 years, and indications for aortic valve replacement. All patients had a regurgitation valve, and the circumference of the aortic annulus was between 71.0 mm and 92.6 mm. The prosthesis valves used included Vitaflow (MicroPort, Shanghai, CN), Evolute R (Medtronic, USA), and Taurus Nxt (Peijia Medical, Suzhou, CN), all of which are self-expanding retrievable valves (Table 1).

Table 1

Patients’ Baseline Characteristics.

Case	Case 1	Case 2	Case 3	Case 4	Case 5	Case 6	Case 7
Baseline
Age	63	68	76	77	70	71	73
Sex	M	F	M	M	F	F	F
Symptom	Chest tightness and shortness of breath	Chest tightness, and activity endurance	Chest tightness, dyspnea, dizziness	Palpitations, chest tightness, chest pain	Shortness of breath	Chest pain, shortness of breath	Shortness of breath, dyspnea
STS score, %	10.5	7.4	5.4	5.5	6.2	5.5	4.8
NYHA	IV	III	II	III	III	III	III
LVEF, %	35	52	65	62	46	58	55
LVDD (mm)	48	60	48	53	60	60	62
CT parameter
Aortic valve type	TAV	TAV	TAV	TAV	TAV	TAV	TAV
Calcification	None	None	Moderate	None	None	None	None
Annulus circumference (mm)	92.6	81.7	71	77	86	81.9	72.9
LVOT circumference (mm)	102.5	83.5	73.8	128.7	88.2	82.8	81.4
Aorta diameter (long × short)	36.2 × 42.5	40.1 × 45.6	39.2 × 38.1	48.3 × 56.5	39.5 × 37.9	45.0 × 42.5	32.7 × 34.3
STJ diameter (long × short)	33.4 × 35.8	30.5 × 32.4	32.7 × 32.0	37.7 × 35.9	35.6 × 35.4	40.5 × 38.5	26.1 × 29.2
Mean Sinus diameter	35.0	36.8	34.5	39.5	38.5	45.2	31.7
LCA height	16.1	15.7	8.3	11.9	14.4	6.7	12.4
RCA height	19.9	18.2	10.5	23.9	21.3	14.7	13.2
Prothesis	30-mm VitaFlow × 2	30-mm VitaFlow × 2	Medtronic 29 mm × 2	27-mm VitaFlow × 2	30-mm VitaFlow × 2	30-mm VitaFlow × 2	Taurus one 29 mm × 2

M, male; F, female; STS, Society of Thoracic Surgeons; NYHA, New York Heart Association; LEF, left ventricular ejection fraction; LVDD, left ventricular end diastolic dimension; LVOT, left ventricular outflow tract; STJ, sinotubular junction; LCA, left coronary artery; RCA, right coronary artery.

In case 1 and case 5, the active SVIS technique was used. In cases 3, 4, and 6, the first valve was placed too low, but during pulling the valve up, the valve jumped up to the ascending aorta. A remedy second valve was then implanted. In cases 2 and 7, the first valve was placed too high and jumped up to the ascending aorta. A passive SVIV was then performed.

The SVIV procedure was successfully performed in all cases except case 5, without any complications (Table 2), including permanent pacemaker implantation. Case 5 was in a 70-year-old man with an annulus circumference of 86 mm; a 30 mm VitaFlow was released in the ascending aorta (Figure 2A). During the release of the second valve, the first valve moved up from the bottom of the sinus, but the operator did not retrieve the second valve and released the valve (Figure 2B). The second valve was 12 mm lower than the first valve (Figure 2C). However, several minutes later, the second valve had moved down into the left ventricle from the first valve, thus causing a severe perivalvular leak and moderate mitral regurgitation (Figure 2D). The patient was then transferred to surgery. We believe that if the second valve had not been released, and had instead been repositioned and released again, according to the steps described above, this complication could have been avoided. All cases except case 5 showed good positioning of the valve stent and hemodynamic valve performance, as assessed with echocardiography at 1 month follow-up.

Figure 2

Intraoperative X-Ray Images of Case 5.

A. A 30-mm self-expanding valve was released in the ascending aorta. B. During the release of the second valve, the first valve moved up from the bottom of the sinus. C. The second valve was 12 mm lower than the first valve. D. The second valve moved down into the left ventricle from the first valve.

Table 2

Patients’ Procedure Outcomes.

Case	Case 1	Case 2	Case 3	Case 4	Case 5	Case 6	Case 7
Procedure type	Active sandwich	Too high for the first valve	Too low; first valve pulled up	Too low; first valve pulled up	Active sandwich	Too low; first valve pulled up	Too high for the first valve
Procedure success	Yes	Yes	Yes	Yes	No	Yes	Yes
Postoperative complications	None	None	None	None	Transfer to surgery	None	None
Postoperative aortic regurgitation	None	None	None	None	-	None	None
Discharge NYHA class	II	I	I	I	-	I	I

Conclusions

Our initial case series results and experience suggest that the new SVIV technique using commercially available self-expanding valves may be an option for treating selected patients with AR at high surgical risk, even those with an extremely large aortic annulus. This technique might also serve as an effective remedy for too high placement of the first valve, reaching the ascending aorta. Compared with the traditional method, this technique can decrease the incidence of complications, particularly conduction block, but several technical details require the operator’s attention. Additional research is necessary to confirm the superiority of this technology. In the absence of further validation studies, this method may be used primarily used as a remedial measure to avoid open-heart surgery and achieve better clinical outcomes, but it cannot be used as a routine procedure for patients with AR. Novel valves might achieve better results for treating AR, but these valves remain in clinical trials and are not yet commercially available [8, 15].

Acknowledgements

The authors thank all participants in this work.

Conflict of Interest

The authors declare no conflicts of interest.

Contributors

All authors contributed to the literature review and the drafting, editing, and final preparation of the manuscript.

Supplementary Material

Video 1. Rapid release of the second valve, while firmly pushing the first valve, to complete the sandwich implantation.

Supplementary Video for this paper can be found at https://youtube.com/shorts/_1Uoxyz8AYs.

Citation Information

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