Case report
A 74 year-old male patient was referred to our department due to
decompensated heart failure. He weighed 83 kg and his height was 178 cm,
with a corresponding body surface area (BSA) of 2,01
m2. Relevant comorbidities included arterial
hypertension, hyperlipidemia, severe pulmonary hypertension, atrial
fibrillation and a previous ischemic stroke. The patient underwent a
biological mitral valve (MV) replacement (Hancock, size 25 mm;
Medtronic, Minneapolis, MN) 4 years prior to presentation for the
treatment of symptomatic severe mixed mitral stenosis with regurgitation
in another cardiac surgery department. At the time, the surgeon noted
severe MAC that prevented insertion of a larger MV prosthesis. The
geometric effective orifice area (EOA) of the Hancock valve prosthesis
size 25mm is 1.46cm2 (1). This led to a severe PPM
(EOA-index 0,72 cm2/m2) immediately
after that initial operation. Two years later, the patient presented
with rapid degeneration and stenosis of the MV prosthesis with severe
symptoms (New York Heart Association (NYHA) class III). A transapical
mitral ViV procedure (Sapien S3, size 23 mm; Edwards Lifesciences,
Irvine, CA) was performed in the same cardiac surgery service, as a
“last stage” measure to relieve symptoms. However, this led to a
higher degree of PPM. Consequently, the patient re-presented to our
department 2 years after transcatheter ViV replacement with severe
dyspnea (NYHA IV) and peripheral edema. Transthoracic echocardiography
revealed recurrent severe mitral stenosis (Pmax / Pmean 37/15 mmHg) and
severe PPM (EOA-Index 0.32 cm2/m2),
as well as markedly decreased right ventricular function and pulmonary
hypertension (systolic PA pressure 45 mmHg). CT-scan revealed extensive
mitral annular calcification (Figure 1 A - C ). Due to the
ineffectiveness of conservative medical therapy and the patient’s
wishes, we decided to perform a high-risk redo surgical MV replacement.
Surgery was performed through median sternotomy and with standard
cannulation for cardiopulmonary bypass (CPB). Intraoperatively, both
highly degenerated MV prostheses could be extracted (Figure 2 A
- C ). Extensive annular decalcification was required to ensure
implantation of an adequately sized MV prosthesis (Figure 2 D ).
In order to prevent atrio-ventricular rupture as a result of the
extensive decalcification, mitral annular reconstruction with a bovine
pericardial patch was performed (Figure 3 ). A mechanical MV
prosthesis (SJM Mitral Modell MJ-501, size 29 mm; Abbott, Chicago, IL)
was thereafter implanted. Weaning from cardiopulmonary bypass (CPB) was
not possible due to severe hypokinesia of the anterior left ventricular
wall as evidenced in the intraoperative transesophageal
echocardiography. It was hypothesized that a piece of calcium had
embolized into the left coronary tree, since the preoperative cardiac
catheterization ruled out significant coronary artery disease.
Therefore, an aortocoronary bypass in beating heart technique (with CPB
support) was performed to the left anterior descendent artery (LAD)
using a saphenous vein graft. Thereafter, CPB could be successfully
weaned. However, the thorax was left open due to a very dilated right
ventricle as well as persistent hemodynamical instability. Cardiac
catheterization was performed immediately after the operation,
confirming calcium embolization with significant main left coronary
occlusion. Proper function of the venous bypass to LAD could be
observed, and the circumflex artery was stented. The patient developed
low cardiac output syndrome thereafter, and an intra-aortic balloon pump
was implanted. The patient developed progressive right heart failure
thereafter with increasing catecholamine doses. Cardiac arrest
subsequently occurred and a percutaneous arterio-venous extracorporeal
life support (ECLS) was emergently implanted under mechanical
cardiopulmonary resuscitation. One day later, the patient developed
fixed and dilated pupils. CT scan revealed generalized cerebral edema
with signs of brain herniation. Supportive measures were withdrawn
shortly thereafter.