Left main coronary artery atresia diagnosed by multidetector computed tomography.

Left main coronary artery atresia is an extremely rare disease. Differential diagnosis of left main coronary artery atresia from atherosclerotic occlusion of left main coronary artery is difficult even if performing invasive coronary angiography. We present a case of a 48-year-old male with left main coronary artery atresia. Echocardiography showed left ventricular dysfunction. Invasive coronary angiography showed absence of left main coronary artery. A multidetector computed tomography showed a string-like structure at the site of left main coronary artery. A diagnosis of left main coronary artery atresia was made, and he underwent coronary artery bypass grafting. At the operation, a thin and not-sclerotic left main coronary artery was observed. Echocardiography, performed after the surgery, showed normalization of the left ventricular systolic function. Multidetector computed tomography might be a useful method to diagnose left main coronary artery atresia.

Development of a Pivot Bearing Supported Sealless Centrifugal Pump for Ventricular Assist.

Since 1991, in our laboratory, a pivot bearing-supported, sealless, centrifugal pump has been developed as an implantable ventricular assist device (VAD). For this application, the configuration of the total pump system should be relatively small. The C1E3 pump developed for this purpose was anatomically compatible with the small-sized patient population. To evaluate an-tithrombogenicity, ex vivo 2-week screening studies were conducted instead of studies involving an intracorpore-ally implanted VADs using calves. Five paracorporeal LVAD studies were performed using calves for longer than 2 weeks. The activated clotting time (ACT) was maintained at approximately 250 s using heparin. All of the devices demonstrated trouble-free performances over 2 weeks. Among these 5 studies, 3 implantations were subjected to 1-month system validation studies. There were no device-induced thrombus formations inside the pump housing, and plasma-free hemoglobin levels in calves were within the normal range throughout the experiment (35, 34, and 31 days). There were no incidents of system malfunction. Subsequently, the mass production model was fabricated and yielded a normalized index of hemolysis of 0.0014, which was comparable to that of clinically available pumps. The wear life of the impeller bearings was estimated at longer than 8 years. In the next series of in vivo studies, an implantable model of the C1E3 pump will be fabricated for longer term implantation. The pump-actuator will be implanted inside the body; thus the design calls for substituting plastic for metallic parts.