CASE PRESENTATION
In August 2018, a 59-year-old woman with a history of severe
rheumatismal mitral stenosis and balloon mitral valvulotomy in 2010 and
2012, respectively, was admitted to our center (Tehran Heart Center)
with a complaint of dyspnea on exertion (functional Class III). The
patient had atrial fibrillation rhythm with an appropriate ventricular
response. Transthoracic and subsequently transesophageal
echocardiographic examinations showed a normal-sized LV with preserved
systolic function (left ventricular ejection fraction [LVEF]
=50–55%), a severely enlarged left atrium, a mildly enlarged right
atrium, and a normal-sized right ventricle with preserved systolic
function. Also visualized were severe rheumatismal mitral stenosis (mean
gradient = 13.6 mm Hg, mitral valve area = 1.3 cm2,
and Wilkins score = 8–10), mild-to-moderate tricuspid regurgitation,
mild mitral regurgitation, mild pulmonary insufficiency with a pulmonary
arterial pressure of 32 mm Hg, and a left atrial appendage thrombus
(8×10 mm). The patient was scheduled for an elective MVR, and she
underwent a routine preoperative coronary angiography (CA) (Fig. 1).
Three days after admission, the patient underwent MVR through
mid-sternotomy. The left atrium was opened with an incision parallel to
the interatrial groove, the aorta was cross-clamped, and cardioplegia
was infused for the replacement of the mitral valve. Next, the anterior
leaflet of the atrium was resected and the valve was replaced. A Regent
St Jude mechanical valve (# 29) was used. About 6 hours after surgery
and before extubation, she developed a sustained monomorphic ventricular
tachycardia, which was instantly cardioverted with direct-current shock
(200 joules biphasic). Thereafter, intravenous amiodarone was started
with a bolus dose of 150 mg and 1 mg/min infusion. She remained in a
stable condition for 10 hours before extubation. About an hour after
extubation, a sustained monomorphic ventricular tachycardia reoccurred,
which was successfully cardioverted to atrial fibrillation rhythm with
direct-current shock (200 joules biphasic). Electrocardiography (ECG)
revealed ST-elevation in the inferior leads during the second episode of
ventricular tachycardia which disappeared after cardioversion. Urgent
transthoracic echocardiography showed a diminished LVEF of 45% with
significant hypokinesia in the LCX territory. The troponin level
exhibited a rise to 1386 ng/L. On suspicion of iatrogenic occlusion in
the coronary arteries, the patient underwent emergency angiography,
which revealed occlusion in the LCX at the mid-part, most probably due
to the compressive effect of the prosthetic valve on the artery (Fig.
2).
There were 2 options for the treatment of the patient: either to perform
redo surgery for the removal of the valve, revascularization of the LCX,
and reimplantation of the valve or to perform percutaneous coronary
intervention (PCI). Time constraints precluded the second option;
therefore, PCI was performed to place a stent, which was unsuccessful. A
decision was then made to place her on conservative medication. While
receiving inotrope agents and anti-ischemic therapy, she was maintained
on the balloon pump for 3 days because of LV hypokinesia and a low LVEF.
The patient was discharged from the hospital 3 days after the removal of
the balloon pump in a stable condition and with improved cardiac
function. Needless to say, generally, the occurrence of such
complications renders the removal of the balloon pump extremely
difficult. Our patient remained stable, with her follow-up
echocardiography on April 27, 2019, demonstrating LVEF of 50%; mild
mitral regurgitation; mild aortic stenosis; a normal functioning
prosthetic mitral valve with good bileaflet motion, acceptable gradient
(mean gradient = 2.5 mm Hg), and minimal paravalvular leak from the
anterior side of the swing ring; and a pulmonary arterial pressure of 27
mm Hg. The study conforms to the ethical guidelines of the 2013
Declaration of Helsinki as reflected in a prior approval by ethics
committee of the Tehran Heart Center.