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Ann Thorac Surg 2005;80:507-510
© 2005 The Society of Thoracic Surgeons
Division of Cardiac Surgery, University of Maryland Medical System, Baltimore, Maryland
Accepted for publication February 3, 2005.
* Address reprint requests to Dr Cardarelli, Division of Cardiac Surgery, University of Maryland Medical System, 22 South Greene St, Suite N4W94, Baltimore, MD 21201 (Email: mcard001{at}umaryland.edu).
Presented at the Poster Session of the Fifty-first Annual Meeting of the Southern Thoracic Surgical Association, Cancun, Mexico, Nov 2–4, 2004.
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Abstract |
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METHODS: Between August 2000 and September 2003, TVR for severe tricuspid insufficiency was performed in 8 patients. Indications were infective endocarditis (7) and iatrogenic damage (1). Mean age was 42.2 years old (20 to 58 years old). Five patients were male and 3 patients had a concomitant procedure (mitral valvuloplasty, coronary bypass grafting, and aortic valve replacement). A stentless aortic root, size 27 mm (n = 5) or 29 mm (n = 3) was placed inverted in the tricuspid position after the valsalva sinuses were scalloped. Interrupted 4-0 polypropylene sutures were used between the tricuspid valve annulus and the sewing ring. The struts equivalent on the stentless valve were anchored to the septal, anterior and posteroinferior wall of the right ventricle using 5-0 PTFE pledgeted sutures.
RESULTS: Hospital survival was 100% and mean hospital stay was 12.5 days (3 to 18 days). Intraoperative and follow-up echocardiograms revealed no stenosis or insufficiency. Mean follow-up was 17.2 months (1–38 months). There were 3 late deaths due to continued IV drug use (n = 2) and end-stage renal failure (n = 1).
CONCLUSIONS: This is a novel surgical alternative for a very high risk population. Potential advantages over current options include minimization of blood contact with nonbiological surfaces, preservation of annular motion, freedom from anticoagulation, and a theoretical lower rate of calcification.
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Introduction |
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Stented biological valves risk early failure due to rapid degeneration and calcification while mechanical valves require anticoagulation. Both types of valves freeze the tricuspid annulus preventing normal systolic motion [1]. We present a simple technique for TVR with the use of a stentless aortic root placed inverted in the annular position.
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Material and Methods |
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TopAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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Since August 2000, 8 consecutive patients (male:female = 5:3), ages 20 to 58 years old (mean 42.2 years old), underwent TVR with a stentless aortic root xenograft (Freestyle, Medtronic, Minneapolis, MN), 27 mm (n = 5) or 29 mm (n = 3) in diameter. Indications for surgery were endocarditis resistant to antibiotic management with symptomatic tricuspid insufficiency and pulmonary embolization in 7 patients. The remaining patient developed severe tricuspid insufficiency after iatrogenic damage to the tricuspid valve by catheter manipulation of a stent lost and trapped in the tricuspid apparatus. Concomitant procedures included mitral valvuloplasty (n = 1), coronary artery bypass grafting times three (n = 1), and aortic valve replacement (n = 1).
Technique
As umbilical tapes around the cavae are tourniqueted down, the right atrium is entered while the heart is beating to minimize cross-clamp time. The infected tricuspid valve and vegetations are excised and removed and the right ventricular cavity is flushed with cold saline to washout residual debris.
The largest fitting stentless aortic root xenograft is tailored appropriately (Fig 1). At this time the aorta is cross-clamped and antegrade blood cardioplegia is administered. Interrupted sutures with pledgets (4-0 polypropylene) are placed between the tricuspid annulus and the xenograft-sewing ring. Care is taken to position the graft in such a way that, once the valve is seated in the annulus, the right ventricular outflow tract will align with one of the valve sinuses.
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Results |
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Infected patients were discharged on long-term intravenous antibiotics or antifungal agents, either to home or to rehabilitation. No anticoagulation regimen was instituted.
Mean follow-up was 17.2 months (1 to 38 months). Transthoracic echocardiogram was performed at last visit in all surviving patients. In all cases there was no gradient across the valve, and no signs of insufficiency. Ventricular function was unchanged from the preoperative ultrasound. Long-term there were 3 deaths at 38, 24, and 2 months due to continued IV drug use (n = 2) and end-stage renal failure (n = 1).
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Comment |
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At our institution TVR represents only 2.1% of all valve replacements performed over the last 10 years. Our decision to replace the valve is not carried lightly as we would always choose a borderline repair over a replacement. During the span of this small series, 50 patients with similar pathology were concomitantly treated by valvuloplasty with or without annuloplasty. As demonstrated in our intraoperative image (Fig 4), the degree of damage when a replacement was decided, at least in our hands, was beyond repair. The case of iatrogenic damage to the valve occurred in a patient with chronic renal failure and an occluded dialysis fistula, subjected to stent placement at the obstruction site. The stent migrated into the heart, being trapped by the tricuspid chordae. Although the interventional radiologist attempt at catheter retrieval was successful at extracting the stent, unfortunately it removed more than 50% of the tricuspid valve leaflets, leaving no option but replacement.
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Late survival after TVR is also inferior to aortic and mitral valve replacement. According to the United Kingdom Valve Registry the 10-year survival rate is only 42.9% [6]. Rizzoli and colleagues [5] reported a 31% and 29% survival rate at 15 and 20 years, respectively. Nakano and coworkers [7] have noted better long-term results with a survival of 68.7% 18 years after the procedure. Among TVR survivors, freedom from reoperation is 100% for mechanical and 90.9% for biological prosthesis at 5 years [4], and 97.7% and 98% at 10 years [6].
Arbulu and associates’ [8] report on simple valvectomy, based on a series of 55 patients, had notable results. Initial surgical mortality was 11%, and late mortality at 13 years was 18%, although patients affected by severe heart failure after valvectomy required prosthetic tricuspid replacement and had dismal results [8]. One clear conclusion is that once symptoms of congestive heart failure have begun in patients who had their tricuspid valve removed, placement of a prosthetic valve would not change the final outcome.
Freedom from reoperation and long-term survival does not seem to be affected by use of mechanical compared with biological valves [4–7]. A review by Rizzoli and colleagues [9] of patients with failing prosthetic valves in different positions determined that the need for re-intervention was not related to the type of device, and a recent metaanalysis on TVR results by the same author again fails to favor a preferential selection for any type of valve [10].
Mitral and tricuspid homografts have been used in a few instances to totally or partially replace the tricuspid valve. Although technically demanding, homografts avoid the use of synthetic material in an infected area [11–13]. Ramsheyi and coworkers [3] suggested a three-step approach; excision of the valve, long-term antibiotic treatment, and followed by homograft valve replacement until blood cultures are cleared [3].
Semilunar valves have been used in the past for tricuspid replacement, but always with the "top-hat" technique. This technique consists of placing the semilunar valve (usually a homograft) inside a tube of Dacron slightly larger in diameter than the homograft itself. The proximal and distal ends of the homograft and the Dacron tube are sutured to each other creating a de-facto stented valve. At this point the distal end of the hybrid graft is attached to the tricuspid annulus, leaving the rest of the prosthesis overhanging into the right atrium (hence its name). The advantage of that technique is that it keeps the right ventricle free of struts by placement of the valve in a supra-annular position. The main drawback of the top-hat technique is the presence of a tube of synthetic material into the right atrium, with a potential for infection, calcification, and clot formation [14, 15].
A number of new biological valves with a softer stent support and subjected to processes to delay calcification have recently come into the market. Although they might achieve similar preservation of the tricuspid annular motion and a prolonged durability, at the present time and as with our series, the long-term results remain in the realm of speculation.
We have no anatomic specimens to show the status of the very small portion of aortic wall remnants or the fate of the commissural attachments. All evaluations of the implanted valve were clinical and echocardiographic (Fig 5). On follow-up echocardiograms there is no evidence of echo-dense images in the portion of aortic wall left behind, which in the absence of infection might signify early calcification. As for the fate of the endocardial attachments of the valve commissures to the myocardium, two of the three attachments are placed through the free wall of the right ventricle, and would unlikely suffer spontaneous detachment. The anchor to the septal wall of the right ventricle is placed with a technique similar to the one used for chordal replacement in mitral valvuloplasty, already proven to have good long term results even when subjected to higher stresses.
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Although repair and in many cases replacement of the tricuspid valve could be achieved without the use of aortic cross clamp, being a new technique we trusted cardioplegic arrest would give us the opportunity to prudently assess valve positioning and commissural attachment.
Summary
Valve replacement, with this or any other technique, should be reserved for those cases in which repair is unfeasible. When unavoidable, a stentless aortic root in the tricuspid position offers, in the short-term and medium-term, a reliable, reproducible alternative for TVR. It avoids the use of anticoagulation, conforms to the tricuspid annulus preserving tricuspid annular motion, allows for the use of transvenous pacemakers and it has, potentially, a lower degree of calcification. Long-term follow-up is needed before this procedure can be accepted as a routine surgical alternative.
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References |
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This article has been cited by other articles:
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  R. J. Shemin Tricuspid Valve Disease Card. Surg. Adult, January 1, 2008; 3(2008): 1111 - 1128. [Full Text]
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 W. B. Keeling, T. S. Maxey, D. Sayad, N. Martini, E. Blazick, and K. E. Sommers A Novel Stentless Mitral Valve Surgical Innovation, March 1, 2007; 14(1): 9 - 11. [Abstract] [PDF]
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