Long term surgical outcome for idiopathic acute rupture of mitral chordae tendineae in infants

Y. Tominaga¹, K. Imai², M. Komori², H. Ichikawa², S. Iwai^1
1Department of Pediatric Cardiac Surgery, National Cerebral and Cardiovascular Center, Suita, Osaka ²National Cerebral and Cardiovascular Center, Suita, Osaka

Purpose: Infantile idiopathic acute mitral valve (MV) chordae tendineae rupture is a rare and rapidly developing circulatory-respiratory failure often requiring emergent surgical treatment. Acute progression, with little mitral valve annulus dilatation and degeneration of valves, limits surgical treatment options. This study aimed to investigate long-term surgical outcomes and our surgical strategy.

Methods: Twenty infants were evaluated who underwent surgical treatment for idiopathic MV chordal rupture at our hospital from 2001 to 2015. Those with bacterial infection, connecting tissue disorder, rheumatic fever, ischemic condition, and congenital lesions were excluded. The median age and weight at surgery were 5.5 months old (interquartile range: 4.5-7.2) and 7.1 kg (5.9-8.0), respectively. Seventeen patients (85%) suffered cardiogenic shock, and three (15%) received cardiopulmonary resuscitation. Preoperative mitral regurgitation (MR) was severe in all patients, with a median mitral annulus diameter of 16.1 mm (14.8-19.2) [z-score 1.1 (0.06-2.5)]. Emergent surgery within 24 hours after admission was necessary for 15 patients (75%).
Infants underwent MV repair with artificial chordae reconstruction using ePTFE sutures and Kay’s annuloplasty or edge-to-edge repair via a right-sided left atrial incision at first. Conversion to mitral valve replacement (MVR) was performed when regurgitation control was unsuccessful.
We investigated the surgical outcomes and factors influencing prognosis.

Results: At the initial surgery, the prolapsed leaflets were anterior in four, posterior in eight, and both in eight cases. The number of prolapsed leaflet segments was 3 (1-3). Twelve patients (60%) exhibited yellowish to reddish edematous degeneration of leaflets and/or papillary muscles. Thirteen patients (65%) underwent MV repair, while seven patients (35%) underwent MVR (primary MVR). Three infants required MVR within one month after MV repair due to worsening MR (early MVR conversion). Reasons for MR exacerbation were additional chordal rupture or progressive degeneration to leaflets.
The median follow-up period was 12.9 years (10.6-14.4) with no mortality.
Among the ten patients discharged after MV repair, eight had less than mild MR, and the other two had moderate MR without re-intervention. Three of the ten patients who underwent initial MVR or early MVR conversion required re-MVR at 9.3 (9.2-10.4) years after MVR due to patient-prosthesis mismatch.
Univariable logistic regression analysis revealed that the degeneration of leaflets and/or papillary muscles (odds ratio 21, 95% CI 1.8-251, P=0.015) and number of prolapsed leaflet segments (odds ratio 4.6/ one segment, 95% CI 1.2-17, P=0.025) were significant factors associated with primary MVR or early MVR conversion.

Conclusion: Prompt valve surgery for acute mitral valve chordae tendineae rupture yielded good long-term results with no mortality. MV repair using artificial chordae reconstruction did not require reoperation during the follow-up period and was a reasonable choice in infancy. Although it would be most desirable for MV repair to be successful, the degeneration of leaflets and papillary muscles and a large number of prolapsed segments were associated with primary MVR or early conversion to MVR.

Identify the source of the funding for this research project: none