This case describes a 36-year-old female patient born in the state of Alagoas, and residing in the municipality of Guarulhos, state of São Paulo, Brazil, married, illiterate, admitted at the Gynecology and Obstetric Service after clinical diagnosis of upper airway infection at the 9^th week of the 1^st pregnancy.

She was followed up at the outpatient clinic specialized in congenital heart defects due to complex congenital heart disease, which included interatrial defect associated with patent ductus arteriosus and interventricular septal defect, as well as a left atrioventricular septal defect. She underwent surgery at the age of eight, consisting of atrioseptoplasty, ventriculoseptoplasty and mitral valve replacement by a mechanical prosthesis. She had paroxysmal atrial fibrillation, with a previous thromboembolic event, left hemisphere ischemic stroke, without neurological sequelae, being asymptomatic from the cardiovascular point of view, in functional class I (NYHA classification) at the last consultation in April 2018. She used only warfarin, undergoing regular follow-up of prothrombin time control/INR, having maintained it between 2-3 in the last controls.

During hospitalization in the Obstetrics Service, warfarin was replaced by enoxaparin 1mg / kg, subcutaneously, every 12 hours, and during the evolution she had atrial fibrillation with high ventricular response accompanied by dyspnea at rest and orthopnea, being subsequently referred to the Emergency Service of the Cardiology Hospital.

The physical examination at admission (May 30, 2018) showed regular overall health status, normal skin color, hydrated, anicteric, conscious, oriented, without alterations at the neurological examination. Cardiovascular examination showed regular heart rhythm, with heart rate at 115 beats per minute, holosystolic murmur, with prosthesis profile, at the superior left sternal border 2 + / 6 +, good peripheral perfusion. The respiratory system showed crackling rales on the left lung base, and mild dyspnea at rest. Gravid abdomen, with no signs of hepatic congestion. Extremities without edema, with no discomfort or pain in the calves.

The laboratory results at admission (May 30, 2018) were: hemoglobin 12.4 g / dL; leukocytes 13,050/mm³ (band cells 1%, segmented 79%, eosinophils 1%); platelets 120,000/mm³; C-reactive protein: 74.6mg / dL; Urinalysis: Leukocytes 16,000/mL, negative nitrite test, bacteria 1+/4+, Urinary culture at the hospital of origin with multisensitive E.coli.

The admission electrocardiogram (May 30, 2018) (Figure 1) showed sinus rhythm, heart rate of 115 bpm, indirect signs of right atrial overload.

Figure 1

The admission chest x-ray (May 30, 2018) (Figure 2) disclosed indirect signs of pulmonary congestion ("cottony" infiltrate, predominantly bibasal), peri-hilar air bronchogram on the right and image compatible with mechanical prosthesis in the mitral position.

Figure 2

The initial diagnosis at hospitalization was bronchopneumonia, pulmonary congestion, atrial fibrillation with high ventricular response, and a single, nine-week non-ectopic pregnancy, and she was prescribed: Ceftriaxone, Clarithromycin, Oseltamivir, Furosemide and Sotalol. The requested exams included blood culture, H1N1 virus screening, transthoracic echocardiography, and Anti-Xa factor.

During the evolution she showed signs and symptoms of pulmonary infectious disease (cough, dyspnea, leukocytosis with left shift, high PCR, with negative H1N1), and it was decided to discontinue Oseltamivir and implement empirical antibiotic therapy with Meropenem.

Compared with the patient’s last transthoracic echocardiogram, the transthoracic echocardiogram carried out on June 4, 2018 disclosed a marked increase in the mitral transvalvular gradient (maximum diastolic gradient of 39mmHg and mean of 25mmHg), in addition to an increase of pressures in the right chambers, with right ventricular systolic pressure of 75 mmHg, with no evidence of thrombi or vegetation (Table 1).

Furosemide and metoprolol were added to the antibiotics aiming at heart rate control, in addition to anticoagulation maintenance with enoxaparin with adequate levels of Anti-Xa factor (between 0.8 and 1U/mL) with improvement of clinical status. A transesophageal echocardiogram was requested for a more adequate assessment of the valve prosthesis (June 14, 2018). This examination showed the reduction in the mobility of the mitral prosthesis components, with a high mean transvalvular gradient (30 mmHg and a hypoechogenic image occupying the central region of the atrial face of the prosthesis, compatible with a thrombus). Its measurements, even underestimated, since it was difficult to determine its full extent using the two-dimensional methodology, reached values of 0.9 x 1.3 cm, resulting in an area of 1.17 cm² (important when > 0.8 cm²) and, thus, the surgical intervention was indicated, since it was available at the service (Table 1). Given the echocardiographic diagnosis of mitral valve prosthesis thrombosis, surgical treatment of the mitral valve was indicated, despite the gestational age, due to the high risk of maternal death. Intravenous unfractionated heparin was then started in an infusion pump while awaiting the surgical procedure.

During this period, the patient developed a new picture of marked dyspnea, with marked congestion (Figure 3), tachycardia, and fever, requiring invasive ventilatory support with orotracheal intubation, and hypotension requiring vasopressor agent (noradrenaline). She went into cardiorespiratory arrest for 6 minutes, with spontaneous circulation and frank shock, requiring high doses of noradrenaline, adrenaline and vasopressin. She remained in shock and, despite the measures, presented with bradycardia and asystole and died (7h22; June 18, 2018). (Dr. Walkíria Samuel Ávila)

Figure 3