Case Presentation
A 70-year-old female patient with hypertension, dyslipidaemia, diabetes mellitus, and no allergic history presented to our emergency care centre with nausea and chest pain 15 min after her second dose of the Pfizer-BioNTech COVID-19 vaccine. Physical examination revealed peripheral cyanosis and the following vital signs: heart rate, 57 beats/min; blood pressure, 84/67 mmHg; respiratory rate, 22 breaths/min; oxygen saturation, 97% in room air; and temperature, 35.6℃. Lung and cardiac auscultation findings were normal.
An initial electrocardiogram (Fig. 1) showed ST-segment elevation in II, III, and aVF and a first-degree atrioventricular block. Transthoracic echocardiograms showed inferior wall hypokinesia. Chest radiography revealed clear bilateral lung fields. Her cardiac enzymes including inflammatory markers (white blood cell count and C reactive protein level) were still normal, showing no acceleration of blood coagulation (D-dimer and fibrinogen). An urgent catheter examination (Fig. 2) showed total occlusion in the right coronary artery (RCA) #3 and 90% stenosis in the left anterior descending artery (LAD) #7.
After catheterisation, percutaneous coronary intervention was performed on the RCA lesion. A red thrombus was obtained by thrombectomy, and the occlusion was released. A new distal occlusion was found in the fourth posterolateral branch artery (#4PL) and posterior descending artery (#4PD) of the RCA (Fig. 3) with residual ST-segment elevation in II, III, and aVF. Intravascular ultrasonography (IVUS) did not identify any obvious plaque rupture whereas continuous diffuse plaques and some unstable like lesions were observed (Fig. 3). TIMI III blood flow was obtained, and there were large amount of blood clots and distal embolization. Therefore, we did not place a stent, but instead placed intra-aortic balloon pumping (IABP) and returned to the ward.
The next day, optical coherence tomography (OCT) was performed to evaluate the unstable vessel. On coronary angiography, the #4PD/PL thrombus had disappeared (Fig. 4). Thrombus and vasa vasorum in the plaque layer (Fig. 4) were observed by OCT, indicating an unstable lesion. Therefore, we implanted a drug-eluting stent in the lesion where the vasa vasorum were present. IABP was discontinued after the intervention. During hospitalisation, the LAD lesion was treated using percutaneous coronary intervention. The patient was on medications, including high-dose statins, for the treatment of myocardial infarction and was recovering well; she was discharged on day 13 following the Japanese Circulation Society guideline. The thrombus contained atheroma with cholesterol crystals and foam cells (Fig. 5).