超音波検査技術

We report a case of a 70-year-old male with leaflet thrombosis in a bioprosthetic aortic valve. The patient had a fever, symptoms and signs of heart failure, and was hospitalized for treatment. We suspected infective endocarditis (IE) and performed transthoracic echocardiography (TTE), but no evidence of IE was found. However, the right coronary cusp of the bioprosthetic valve showed dysfunction because it did not move flexibly with thrombosis. The aortic valve mean gradient (mPG) was 15 mmHg, the 6-month postoperative variation in mPG (ΔmPG) showed an increase of 6 mmHg, and the peak velocity (Vmax) was 2.7 m/s by TTE. A blood culture result was negative. We started anticoagulation therapy with warfarin, and subsequent TTE did not show any signs of dysfunction of the bioprosthetic valve (mPG: 9 mmHg, ΔmPG: 0 mmHg, Vmax: 2.2 m/s). In general, computed tomography is useful for evaluation of thrombotic valves, but this case illustrated the value of TTE for diagnosis and follow-up. Previous reports have also observed that inflammation can activate the coagulation process. It is possible that a crack or scratch on a bioprosthetic valve in patients with high C-reactive protein levels could cause thrombotic valve dysfunction. When there is a positive inflammatory reaction in a patient with a bioprosthetic valve, we should generally suspect IE, but it is essential to carefully observe the changes in the leaflets if thrombus adhesion is suspected.