The ability of ultrasound to produce highly controlled tissue erosion was investigated. This study is motivated by the need to develop a noninvasive procedure to perforate the neonatal atrial septum as the first step in treatment of hypoplastic left heart syndrome. A total of 232 holes were generated in 40 pieces of excised porcine atrial wall by a 788 kHz single-element transducer. The effects of various parameters [e.g., pulse repetition frequency (PRF), pulse duration (PD), and gas content of liquid] on the erosion rate and energy efficiency were explored. An Isppa of 9000 W/cm2, PDs of 3, 6, 12, and 24 cycles; PRFs between 1.34 kHz and 66.7 kHz; and gas saturation of 40-55% and 79-85% were used. The results show that very short pulses delivered at certain PRFs could maximize the erosion rate and energy efficiency. We show that well-defined perforations can be precisely located in the atrial wall through the controlled ultrasound tissue erosion (CUTE) process. A preliminary in vivo experiment was conducted on a canine subject, and the atrial septum was perforated using CUTE.

The incidence of KD in South Korea increased to 194.7 per 100,000 children younger than 5 years in 2014; meanwhile, the coronary aneurysm rate decreased to 1.7%.

Background: This study aimed to investigate recent epidemiologic features of Kawasaki disease (KD) in South Korea. Methods: The ninth triennial nationwide questionnaire survey collected data on the demographic findings, symptoms and signs, treatment patterns and coronary artery complications of acute-phase KD occurred in 2015–2017 from 98 hospitals with pediatric residency programs and 108 community hospitals without residency programs. Results: We received data from 93 of the 98 hospitals (response rate: 94.9%) with residency programs and 75 of the 108 community-based children’s hospitals (response rate: 69.4%) without residency programs. In the 3-year survey period, a total of 15,378 (5449 in 2015, 5171 in 2016 and 4758 in 2017) cases of KD were reported. The mean age at diagnosis was 33.0 ± 24.8 months (range: 0–205 months), and the male-to-female ratio was 1.41:1. The overall KD incidence was 196.9 (202.2 in 2015, 197.1 in 2016 and 191.0 in 2017) per 100,000 younger than 5 years population. Recurrent cases were 4.85%. KD occurred more frequently during winter (December–January) and late spring (May–June). Intravenous immunoglobulin (IVIG) was administered to 95% of the patients; nonresponder rate for the first IVIG was 14.8%. Coronary artery aneurysms and giant coronary artery aneurysms (internal diameter >8 mm) occurred in 1.7% and 19 patients, respectively. Two patients died due to multiorgan failure and hepatic encephalopathy. Conclusion: Peak incidence of KD in South Korea was 202.2 per 100,000 younger than 5 years population (2015), and the incidence of giant coronary artery aneurysm decreased to 0.09% (2017).