Rfp. Deac et al., NEW EVOLUTION IN MITRAL PHYSIOLOGY AND SURGERY - MITRAL STENTLESS PERICARDIAL VALVE, The Annals of thoracic surgery, 60(2), 1995, pp. 433-438
The human adult mitral valve, with a mean diastolic area of up to 7.6
cm(2), excess leaflet surface area for coaptation in systole, mitral a
nnulus-papillary muscle continuity, and systolic constriction of the p
osterior left ventricular wall around the mitral annulus functions in
concert with other components of the left side of the heart. Mitral va
lve replacement with an artificial valve that interferes with the norm
al physiology could account for less than adequate late results. A ste
ntless biologic mitral valve substitute has been designed, constructed
, and tested. The size of the valve is selected according to the circu
mference of the excised valve within certain limits. The valve is manu
factured of two square or trapezoidal pieces of selected stabilized hu
man autologous or bovine pericardium. The pericardial pieces are sutur
ed together by their lateral margins, thus creating a frusto-conical v
alvular body. The upper circumference of the valvular body is sutured
at the mitral annulus and the lower margin with the new chordae is att
ached by suture at each papillary muscle. In vitro testing of six sten
tless bovine pericardial valves in a Rowan-Ash fatigue tester at 1,200
cycles/min revealed a durability of more than 320 million cycles. Cli
nical use of described technique initiated in 1989 was performed in 18
patients by one surgeon (30 patients in the same institution). The me
an valve size was 29 mm circularized diameter. There was no mortality
in this group of patients up to 70 months of follow-up. Valve competen
ce was obtained in every case by adequate sizing of the valve. One reo
peration was necessary at 3 months for rupture at the papillary muscle
suture, early in the series. One late endocarditis required reoperati
on at 16 months. Sixteen patients were followed up for a mean of 26 mo
nths. Echocardiography revealed normal function of the valves with a m
ean orifice area of 4.43 +/- 1.24 cm(2) (standard deviation; n = 11) a
nd a mean valve index of 2.6 cm(2)/m(2). There was one late thromboemb
olic complication in a patient with atrial fibrillation who stopped an
ticoagulant treatment. All patients with indications are on limited an
ticoagulation. A mitral stentless pericardial valve with large orifice
and mitral annulus-papillary muscle continuity can function adequatel
y up to a current 70 months after the operation.