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.