Valve-in-Valve Therapy

13.1

Key Points

• Transcatheter valve implantation is feasible in failing surgical aortic, mitral, pulmonic and tricuspid bioprostheses.

• Access may be transarterial (femoral, subclavian, axillary), transvenous (femoral, subclavian, jugular), transapical, transatrial, or direct transaortic.

• Paravalvular regurgitation (PR) must be distinguished from valvular regurgitation, because it will not respond to valve-in-valve (VIV) implants.

• The specific model and the labeled (external) diameter of the bioprosthesis must be confirmed.

• The internal diameter of the bioprosthesis must be determined from the manufacturer and noninvasive imaging.

• The transcatheter valve size must match or exceed the internal diameter of the surgical bioprosthesis.

• VIV implantation in very small surgical bioprostheses may lead to high transvalvular gradients.

• The radiographic and echocardiographic appearance of the surgical bioprosthesis posts and sewing ring should be understood.

• Transcatheter valves depend largely on anchoring within the sewing ring, not the stent posts.

• The durability of VIV implants is unknown at the present time.

Reoperative replacement of failing bioprosthetic heart valves carries a higher risk of morbidity and mortality than the initial valve replacement procedure. An alternative to reoperation is transcatheter VIV implantation. Transcatheter VIV implantation has been successfully performed for failing surgical bioprostheses in the aortic, mitral, pulmonic, and tricuspid positions. This chapter covers the practical challenges, selection criteria, techniques, and outcomes of VIV implantation.

13.2

Causes of Bioprosthetic Valve Failure

Bioprosthetic valves are derived from animal tissue (xenograft or heterograft) or from human tissue (homograft). The most commonly used biologic materials are porcine aortic valve and bovine pericardial tissue. In stented bioprostheses the leaflet tissue is suspended from a frame made of various alloys or plastics. The stent is seated on a basal ring, which may be circular or saddle shaped. Freedom from bioprosthetic valve failure is reportedly 70% to 90% at 10 years and 40% to 70% at 15 years. Failure may occur because of stenosis, regurgitation, both of these, or a paravalvular leak.

A major contributor to bioprosthetic failure is calcification, which involves an interaction between phospholipids, glutaraldehyde collagen cross-linking, and circulating calcium. Younger age at implantation, diabetes, renal failure, and abnormalities of calcium metabolism such as hyperparathyroidism are risk factors for accelerated valve calcification. Structural failure may also occur as a result of a leaflet tear, which may occur in the absence of calcification. Typically this occurs in the area of the commissures, where the leaflet stress is highest. Whereas growth of host tissue onto the valve frame is part of a natural healing process, proliferative overgrowth with pannus restricts leaflet mobility. Additional mechanisms of structural valve failure include infective endocarditis and valve thrombosis, both contraindications for VIV procedures.

13.3

Patient Selection and Indications for Valve-in-Valve Therapy

Transcatheter VIV implantation may be considered in patients with failing surgical bioprostheses caused by severe regurgitation, stenosis, or both, regardless of surgical valve position. Significant PR has to be excluded, because it does not respond to VIV therapy. Endocarditis and valve thrombosis are generally considered contraindications. The lack of long-term durability data restricts VIV procedures to patients at high or prohibitive surgical risk. Furthermore, the internal diameter of the surgical bioprosthesis limits the size of the transcatheter heart valve (THV), which is of concern when dealing with a very small bioprosthesis. Patients need to undergo thorough screening to determine the most appropriate access site that allows safe and effective THV delivery. Comorbidities that may influence life expectancy should be taken into account before pursuing with VIV treatment.

Dimensions of Surgical Bioprosthetic Heart Valves

Surgical bioprostheses are usually referred to according to their labeled size, a number that roughly corresponds to the diameter in mm of the aortic annulus as determined by a surgeon intraoperatively. This labeled size does not refer to the internal diameter of the valve, which is the most important diameter to consider in VIV treatment ( Figure 13–1 ). In most cases the labeled size corresponds to the outer diameter of the stent; however, in the case of stentless valves it typically corresponds to the external diameter of the valve. Unfortunately valve size labeling varies by manufacturer and is not standardized; moreover, different models of valves with the same reported label size (external diameter) may have different internal diameters.

A surgical operative report or patient valve implant card should be obtained to verify the specific manufacturer, model, and labeled size of the valve actually implanted. The internal diameter should then be ascertained from the manufacturer. The dimensions of a range of commonly implanted surgical bioprostheses are found in Tables 13–1 to 13–3 . The nominal external diameter of the THV for VIV implantation should match or exceed the internal diameter of the surgical bioprosthesis. Undersizing the THV may lead to intervalvular regurgitation or embolization. Excessive oversizing of the THV may result in underexpansion of the THV frame within the surgical bioprosthesis and lead to compromised hemodynamics and leaflet durability. In the authors’ experience, underexpansion up to 20% of the nominal THV diameter is generally acceptable. However, sizing considerations should not only take into account the internal prosthesis diameter, but also the nature of surgical bioprosthetic valve failure. Highly calcified, stenotic valves or those with prominent pannus may have smaller internal diameters. Imaging findings from computed tomography or transesophageal echocardiography should be taken into account when assessing THV sizing. However, their accuracy and reproducibility have not been tested for this indication.

TABLE 13–1

Valve Dimensions for Selected 18- to 23-mm Surgical Bioprostheses, as per Manufacturer Product Information

(Reprinted with permission from Elsevier; Gurvitch, R, Cheung, A, Ye, J, et al: Transcatheter valve-in-valve implantation for failed surgical bioprosthetic valves. J Am Coll Cardiol 58:2196-2209, 2011.)

Valve Label Size	Valve Type/Model	External Sewing Ring Diameter (ED), mm	Stent Outer Diameter (OD), mm	Internal Stent Diameter (ID), mm
18	Soprano (Sorin)	26	21	17.8
19	Magna (Edwards Lifesciences)	24	19	18
	Perimount (Edwards Lifesciences)	26	19	18
	Mosaic (Medtronic)	25	19	17.5
	Hancock Ultra (Medtronic)	24	19	17.5
	Hancock II (Medtronic)	N/A	N/A	N/A
	Mitroflow (Sorin)	21	18.6	15.4
	Trifecta (St. Jude Medical)	24	19	N/a
	Epic/Bicor (St. Jude Medical)	N/A	N/A	N/A
	Epic Supra/Bicor Supra (St. Jude Medical)	N/A	N/A	N/A
20	Soprano (Sorin)	28	23	19.8
21	Magna (Edwards Lifesciences)	26	21	20
	Perimount (Edwards Lifesciences)	29	21	20
	Mosaic/Hancock II (Medtronic)	27	21	18.5
	Hancock/Hancock Ultra (Medtronic)	26	21	18.5
	Mitroflow (Sorin)	23	20.7	17.3
	Trifecta (St. Jude Medical)	26	21	N/A
	Epic/Bicor (St. Jude Medical)	N/A	21	19
	Epic Supra/Bicor Supra (St. Jude Medical)	N/A	21	21
22	Soprano (Sorin)	30	25	21.7
23	Magna (Edwards Lifesciences)	28	23	22
	Perimount (Edwards Lifesciences)	31	23	22
	Mosaic/Hancock II (Medtronic)	30	23	20.5
	Hancock/Hancock Ultra (Medtronic)	28	23	22
	Mitroflow (Sorin)	26	22.7	19
	Trifecta (St. Jude Medical)	28	23	N/A
	Epic/Biocor (St. Jude Medical)	N/A	23	21
	Epic Supra/Biocor Supra (St. Jude Medical)	N/A	23	23

TABLE 13–2

Valve Dimensions for Selected 24- to 29-mm Surgical Bioprostheses, as per Manufacturer Product Information

(Reprinted with permission from Elsevier; Gurvitch, R, Cheung, A, Ye, J, et al: Transcatheter valve-in-valve implantation for failed surgical bioprosthetic valves. J Am Coll Cardiol 58:2196-2209, 2011.)

Valve Label Size	Valve Type/Model	Sewing Ring External Diameter (ED), mm	Stent Outer Diameter (OD), mm	Stent Internal Diameter (ID), mm
24	Soprano (Sorin)	32	27	23.7
25	Magna (Edwards Lifesciences)	28	23	22
	Perimount (Edwards Lifesciences)	31	23	22
	Mosaic/Hancock II (Medtronic)	30	23	20.5
	Mosaic Ultra/Hancock I Ultra (Medtronic)	30	25	22.5
	Mitroflow (Sorin)	29	25.1	21
	Trifecta (St. Jude Medical)	31	25	N/A
	Epic/Biocor (St. Jude Medical)	N/A	25	23
	Epic Supra (St. Jude Medical)	N/A	25	25
26	Soprano (Sorin)	35	29	25.6
27	Magna (Edwards Lifesciences)	32	27	26
	Perimount (Edwards Lifesciences)	35	27	26
	Mosaic/Hancock II (Medtronic)	36	27	24
	Mosaic Ultra/Hancock II Ultra (Medtronic)	32	27	24
	Mitroflow (Sorin)	31	27.3	22.9
	Trifecta (St. Jude Medical)	33	27	N/A
	Epic/Biocor (St. Jude Medical)	N/A	27	27
	Epic Supra (St. Jude Medical)	N/A	27	27
28	Soprano (Sorin)	38	31	27.6
29	Magna (Edwards Lifesciences)	34	29	28
	Perimount (Edwards Lifesciences)	37	29	28
	Mosaic/Hancock II (Medtronic)	39	29	26
	Mosaic Ultra/Hancock II Ultra (Medtronic)	34	29	26
	Mitroflow (Sorin)	33	29.5	24.7
	Trifecta (St. Jude Medical)	35	29	N/A
	Epic/Biocor (St. Jude Medical)	N/A	29	27
	Epic Supra (St. Jude Medical)	N/A	N/A	N/A

TABLE 13–3

Valve Dimensions for Selected Stentless Valves, as per Manufacturer Product Information

(Reprinted with permission from Elsevier; Gurvitch, R, Cheung, A, Ye, J, et al: Transcatheter valve-in-valve implantation for failed surgical bioprosthetic valves. J Am Coll Cardiol 58:2196-2209, 2011.)

Valve Label Size	Bioprosthesis	Company	Outer Diameter (OD), mm	Internal Diameter (ID), mm
19	Freestyle	Medtronic	19	16
	Prima Plus	Edwards	19	16
	3F Therapeutics	ATS Medical	19	17
	Toronto SPV	St. Jude Medial	N/A
	Pericarbon Freedom	Sorin Biomedical	19	17
21	Freestyle	Medtronic	21	18
	Prima Plus	Edwards	21	18
	3F Therapeutics	ATS Medical	21	19
	Toronto SPV	St. Jude Medial	21	18
	Pericarbon Freedom	Sorin Biomedical	21	19
23	Freestyle	Medtronic	23	20
	Prima Plus	Edwards	23	20
	3F Therapeutics	ATS Medical	23	21
	Toronto SPV	St. Jude Medial	23	20
	Pericarbon Freedom	Sorin Biomedical	23	21
25	Freestyle	Medtronic	25	21
	Prima Plus	Edwards	25	21
	3F Therapeutics	ATS Medical	25	23
	Toronto SPV	St. Jude Medial	25	21
	Pericarbon Freedom	Sorin Biomedical	25	23

13.4