Complications of supra-annular mitral valve placement in infants

Mitral valve replacement in children: balancing durability and risk with mechanical and bioprosthetic valves

OBJECTIVES

To investigate if there is still a place for bioprosthetic mitral valve replacement in children by comparing the prosthetic durability and transplant-free survival after bioprosthetic and mechanical mitral valve replacement.

METHODS

We reviewed all mitral valve replacements in children between 1981 and 2020. Bioprosthetic mitral valve replacement cases were individually matched to mechanical mitral valve replacement cases. The incidence rate of a 2nd replacement was calculated using the cumulative incidence function that considered death or transplantation as a competing risk.

RESULTS

The median age at implantation was 3.6 years (interquartile range 0.8-7.9) for the bioprosthetic valve cohort (n = 28) and 3 years (interquartile range 1.3-7.8) for the mechanical valve cohort (n = 28). Seven years after bioprosthetic mitral valve replacement, the cumulative incidence of death or transplantation was 17.9% [95% confidence interval (CI) 6.3-34.1] and the cumulative incidence of a 2nd replacement was 63.6% (95% CI 39.9-80.1). Seven years after mechanical mitral valve replacement, the cumulative incidence of death or transplantation was 28.6% (95% CI 13.3-46) and the cumulative incidence of a 2nd replacement was 10.7% (95% CI 2.6-25.5). Fifteen years after mechanical mitral valve replacement, the cumulative incidence of death or transplantation was 33.6% (95% CI 16.2-52.1) and the cumulative incidence of a 2nd replacement was 41.1% (95% CI 18.4-62.7). The cumulative incidence curves for bioprosthetic and mechanical mitral valve replacement were statistically different for a 2nd valve replacement (P < 0.001) but not for death or transplantation (P = 0.33).

CONCLUSIONS

There is no difference in transplant-free survival after bioprosthetic and mechanical mitral valve replacement in children. The lifespan of bioprosthetic mitral valves remains limited in children because of structural valve failure due to calcification. After 15 years, 40% of mechanical valves were replaced, primarily because of patient-prosthesis mismatch related to somatic growth.

Infant Mitral Valve Replacement: Current State of the Art

Mitral valve replacement (MVR) in the very young is an imposing clinical challenge. Early and late mortality risk is substantial, severe adverse events are common, and redo mitral valve replacement is inevitable. Therapeutic options are limited. In the older infant with an annulus of 17mm or larger, mechanical MVR is associated with low risk of mortality and predictable durability. For the very young with annular hypoplasia, bovine jugular vein conduit MVR appears to offer equivalent or better early outcomes with the possibility of subsequent valve expansion, potentially prolonging the interval to redo MVR. Experience with cylinder MVR and other forms of surgeon-manufactured MVR is quite limited, and there is currently no information on late outcomes or durability.

Mitral valve replacement in infants and younger children

Data on mitral valve replacement (MVR) in young children is still limited. Our objective was to evaluate MVR in children below 5 years and identify factors affecting the outcomes. This retrospective study included 29 patients who had MVR from 2002 to 2020. We grouped the patients into two groups according to their age: age ≤ 24 months (n = 18) and > 24 months (n = 11). Primary cardiac diagnoses were Shone complex (n = 7; 24%), isolated congenital mitral valve abnormality (n = 11; 38%), and complete atrioventricular septal defect (n = 3; 10%). The median age was 19 month (25th–75th percentile: 11–32) and 59% were females (n = 17). The hemodynamic lesions were mitral regurgitation in 66%, mitral stenosis in 10%, and combined mitral stenosis and regurgitation in 24% of the patients. St. Jude mitral valve was the most common valve implanted (n = 19, 66%), followed by CarboMedics in 21% of the patients (n = 6). The mitral valve was implanted in the supra-annular position in 6 cases (21%). Preoperative and operative data were comparable between both groups. There was no association between valve size and position with postoperative heart block (P > 0.99, for both). The median follow-up duration was 19.4 months (8.6–102.5). Nine patients had mitral valve reoperation, six had MVR, and three had clot removal from the mitral valve. There was no effect for age group on reoperation (SHR 0.89 (95% CI 0.27–2.87), P = 0.84). Valve size significantly affected reoperation (SHR 0.39 (95% CI 0.18–0.87), P = 0.02). The supra-annular position was associated with an increased risk of reoperation (SHR 3.1 (95% CI 1.003–9.4), P = 0.049). There was no difference in survival according to the age (Log-rank P = 0.57) or valve size (Log-rank P = 0.66). Mitral valve replacement in children is associated with low morbidity and mortality. The risk of reoperation could be affected by the valve size and position rather than the age.

Replacement of the Mitral Valve Under One Year of Age: Size Matters

Surgical management of mitral valve disease in neonates and infants is challenging. When repair is no longer feasible, replacement may become inevitable, but should only be considered as an option of last resort due to the remarkably high rate of associated morbidity and mortality. Mechanical valves are the preferred choice in large annuli, while stented conduits seem promising in smaller ones. In patients with a preoperative mitral valve annulus equal or larger than 15-16 mm, an intra-annular placement of the smallest mechanical valve available should be attempted. In patients with smaller annuli, the placement of a stented valved conduit seems to display a lower mortality risk. Supra-annular implantation of prostheses should be reserved for exceptional cases and to those familiar with this technique because of the high rate of associated complications.

Patient-Specific Approach to Mitral Valve Replacement in Infants Weighing 10 kilograms or less

Background:

Mitral valve replacement (MVR) is the only option for infants with severe mitral valve disease that is not reparable; however, previously reported outcomes are not always favorable. Our institution has followed a tailored approach to sizing and positioning of mechanical valve prostheses in infants requiring MVR in order to obtain optimal outcomes.

Methods:

Outcomes for 22 infants ≤10 kg who have undergone MVR in Sydney, Australia, from 1998 to 2016, were analyzed. Patients were at a mean age of 6.8 ± 4.1 months (range: 0.8-13.2 months) and a mean weight of 5.4 ± 1.8 kg at the time of MVR. Most patients (81.8%) had undergone at least one previous cardiac surgical procedure prior to MVR, and 36.4% had undergone two previous procedures. Several surgical techniques were used to implant mechanical bileaflet prostheses.

Results:

All patients received bileaflet mechanical prostheses, with 12 receiving mitral prostheses and 10 receiving inverted aortic prostheses. Surgical technique varied between patients with valves implanted intra-annularly (n = 6), supra-annularly (n = 11), or supra-annularly with a tilt (n = 5). After a mean follow-up period of 6.2 ± 4.4 years, the survival rate was 100%. Six (27.3%) patients underwent redo MVR a mean of 102.2 ± 10.7 months after initial MVR. Four (18.2%) patients required surgical reintervention for development of left ventricular outflow tract obstruction and three (13.6%) patients required permanent pacemaker placement during long-term follow-up.

Conclusions:

The tailored surgical strategy utilized for MVR in infants at our institution has resulted in reliable valve function and excellent survival. Although redo is inevitable due to somatic growth, the bileaflet mechanical prostheses used displayed appropriate durability.

Mitral valve replacement using mechanical prostheses in children: early and long-term outcomes

Compared with mitral repair, mitral valve replacement is an uncommon procedure in children due to associated high mortality and morbidity rates. The present study investigated early and late outcomes after MVR with mechanical prostheses in children at our institution. Between January 1994 and December 2009, 19 children underwent MVR. Mean patient age was 7.6 ± 5.5 years (range 3 months-16 years), and mean body weight was 23.7 ± 15.1 kg (range 5.0-58.1 kg). Mean prosthesis size was 25.8 ± 4.2 mm (range 19-31 mm). There were no operative or late mortalities. Three patients showed decreased left-ventricular function before surgery, and one of them underwent successful heart transplantation due to progressive LV dysfunction at 10 months after MVR. The proportion of patients with freedom from reoperation at 10 years was 94.7 ± 5%. There were no major thromboembolic or bleeding episodes. Although the small number of patients in our study was a limitation, MVR in children was found to result in excellent early and long-term outcomes. It appears that MVR could be considered in children before LV dysfunction develops.

Clinical characteristics of acute mitral regurgitation due to ruptured chordae tendineae in infancy-experience at a single institution

In infants, acute mitral regurgitation resulting from ruptured chordae tendineae is very rare, but often fatal. There are a few case reports, but the characteristics and etiology of chordae tendineae rupture have not been elucidated. Our aim was to determine the clinical characteristics of idiopathic acute mitral regurgitation due to chordal rupture in infancy. A retrospective analysis was performed on ten consecutive patients, with a mean onset age of 4.6 ± 1.3 months. Despite nonspecific initial symptoms, all patients developed respiratory distress and four required resuscitation within a few days (mean, 1.8 ± 1.8 days). Chest radiographs showed pulmonary congestion with a normal or mildly increased cardiothoracic ratio in all ten patients. Laboratory data and electrocardiograms showed nonspecific findings. Echocardiography revealed ruptured chordae in all patients; locations were anterior (50%), posterior (20%), and both (30%). Surgical intervention was performed within 24 h of admission in eight patients (mean, 3.6 ± 5.1 h). Pathological findings included inflammatory cells in six specimens and myxomatous degeneration in two. No bacteria were isolated from preoperative blood cultures, pathological tissues, or excised tissue cultures. Autoantibody levels were insignificant. Three preoperatively resuscitated patients developed neurological sequelae and arrhythmias occurred in four after mitral valve replacement. Acute onset and rapid deterioration in patients with ruptured chordae tendineae necessitates early surgical intervention to improve outcomes. Though the etiology remains unknown, onset is in infants approximately 4 months of age, suggesting a definite disease entity.

[Surgical management with mitral valve replacement in young infants with congenital mitral valve diseases and complete atrioventricular septal defect]

OBJECTIVES

The mechanical valve replacement may be the only option if the failing mitral valve cannot be repaired in complete AV septal defect (CAVSD), or congenital mitral valve stenosis and regurgitation in infants. In young infants the small mitral annulus-prosthesis mismatch is a big problem.

AIM

To assess the possibility of the left AV orifice repair and the necessity of mechanical valve replacement in CAVSD in young infants.

METHODS

Single center, retrospective study of 82 infants (13 pts under 3 months) who underwent complete repair of CAVSD between 2001 and 2007. Mechanical (bileaflet) valve replacement was required in 7 pts (5 weeks-7 months, 3.5-5 kg). The time interval between the two operations was 0-7 days, but the smallest baby spent 38 days in the intensive care unit waiting for increasing of his mitral annulus size from 11 to 15 mm. (Types of implanted valves: 2 Carbomedics 16 mm, 3 ATS 16 mm, 1 Sorin 17 mm, 1 Sorin 19 mm.) ATS 16 mm valves were implanted in 2 infants each with congenital mitral valve stenosis and regurgitation.

RESULTS

Early mortality (30 days) was 0, but 2 pts died in sepsis on the 46th and 71st postoperative day, respectively. In the follow-up period of 1-6 (mean 3) years 1 child (18 months later) needed reoperation (pannus removal), now all pts are doing well. Anticoagulation therapy was difficult in some cases without complication.

CONCLUSIONS

The surgical repair of congenital mitral valve diseases and CAVSD can be performed successfully in very young infants. If the anatomic characteristics of the mitral valve is not suitable for repair, only mechanical mitral valve replacement can be performed successfully even in sometimes hopeless situation (one of our pts of 3.5 kg weight, is the smallest baby mentioned in the literature). Our early and mid-time results are good, but the re-replacement will be an unavoidable problem in the future.

Mitral valve replacement in infants and children 5 years of age or younger: evolution in practice and outcome over three decades with a focus on supra-annular prosthesis implantation

OBJECTIVE

Successful mitral valve replacement in young children is limited by the lack of small prosthetic valves. Supra-annular prosthesis implantation can facilitate mitral valve replacement with a larger prosthesis in children with a small annulus, but little is known about its effect on the outcomes of mitral valve replacement in young children.

METHODS

One hundred eighteen children underwent mitral valve replacement at 5 years of age or younger from 1976-2006. Mitral valve replacement was supra-annular in 37 (32%) patients.

RESULTS

Survival was 74% +/- 4% at 1 year and 56% +/- 5% at 10 years but improved over time (10-year survival of 83% +/- 7% from 1994-2006). Factors associated with worse survival included earlier mitral valve replacement date, age less than 1 year, complete atrioventricular canal, and additional procedures at mitral valve replacement, but not supra-annular mitral valve replacement. As survival improved during our more recent experience, the risks of supra-annular mitral valve replacement became apparent; survival was worse among patients with a supra-annular prosthesis after 1991. A pacemaker was placed in 18 (15%) patients within 1 month of mitral valve replacement and was less likely in patients who had undergone supra-annular mitral valve replacement. Among early survivors, freedom from redo mitral valve replacement was 72% +/- 5% at 5 years and 45% +/- 7% at 10 years. Twenty-one patients with a supra-annular prosthesis underwent redo mitral valve replacement. The second prosthesis was annular in 15 of these patients and upsized in all but 1, but 5 required pacemaker placement for heart block.

CONCLUSIONS

Supra-annular mitral valve replacement was associated with worse survival than annular mitral valve replacement in our recent experience. Patients with supra-annular mitral valve replacement were less likely to have operative complete heart block but remained at risk when the prosthesis was subsequently replaced.

Congenital mitral valve surgery: techniques and results

PURPOSE OF REVIEW

Congenital lesions of the mitral valve are rare. Conservative surgery is recognized as the best option. In complex anatomy, however, replacement is the only solution to achieve an acceptable result. This review aims to study the long-term follow-up of classical treatments, conservative or replacement, and to examine new technical advances.

RECENT FINDINGS

The long-term results of conservative surgery are confirmed with a low incidence of reoperation except in mitral valve stenosis. The Ross II operation using a pulmonary autograft is a difficult technique that may be useful in the youngest patient group when prosthetic devices cannot be used.

SUMMARY

In the last few years, surgery of congenital mitral valve lesions has gained from echocardiography, which shows the exact function and anatomy of the mitral valve. The tendency is to avoid multistage operations. Valve replacement by biologic material (Ross II) is still under clinical evaluation.