Rupture ofposterior wallofleft ventricle after mitral valve replacement

Possible aetiological factors, presentation, andmanagement were reviewed in18 patients withposterior left ventricular rupture complicating mitral valve replacement seenatone centre oversixandahalf years.Thepatients wereelderly (meanage57), predominantly women (16ofthe18), andsuffering frommitral stenosis. Rupture wasmuchmorecommonafter isolated replacemenit ofthemitral valve (16outof797operations) thanafter double valve replacement (oneout236)ormitral valvereplacement andcoronaryartery bypass graft (oneoutof70).A total of1221mitral valve replacements were performed overthis period, withanoverall inci- denceofrupture of1i47%. Damagetothevalve annulus occurred five times. Onfouroccasions haemorrhage followed avigorous responsetoabolus doseofaninotrope. Withtheexception of these features, itwas difficult todefine specific riskfactors. Elevenpatients bledwhilestill in theatre; one ofthemsurvived longtermandanother fourlived forfourto10days. Repair after restarting cardiopulmonary bypass madeshort termsurvival muchmore likely. Insevenrupture developed after return totheintensive therapy unit; again only one survived long term.Innearly all casesbleeding was at,orjust below, theatrioventricular groove. Rupture probably occursafter endocardial damagetoa thinmyocardium thathaslostthe internal buttress ofthesubvalvar apparatus. Withtherise inintraventricular pressureattheend ofbypass blooddissects intothemyocardium, resulting ina large haematomaandeventual rupture.