In Jai Kim

Solidification microstructure of as-cast Mg–Zn–Y alloys

Composites consisting of icosahedral (i) phase and ductile α-Mg can be fabricated by controlling the alloy composition. With increasing Mg content, the primary solidification phase changed from the i phase to the α-Mg phase and single eutectic structure can be obtained at a composition of Mg72Zn23.5Y3.5. The i phase showed a variation in structural order from the well-ordered icosahedral phase to the 1/1 rhombohedra1 approximant with lattice constants a=27.2 Å and α = 63.43°. The structural change in the i phase can be explained by microdomain formation due to compositional change during solidification. Annealing treatment improves the structural order of the i phase by homogenization. By controlling the alloy composition, a single eutectic structure consisting of a hard i phase and a ductile α-Mg phase could be obtained.

Association of insulin resistance and coronary artery remodeling: an intravascular ultrasound study

BackgroundThere are few studies that investigated the correlation between insulin resistance (IR) and the coronary artery remodeling. The aim of the study is to investigate the association of IR measured by homeostasis model assessment of insulin resistance (HOMA-IR) and coronary artery remodeling evaluated by intravascular ultrasound (IVUS).MethodsA total of 298 consecutive patients who received percutaneous coronary interventions under IVUS guidance were retrospectively enrolled. The value of HOMA-IR more than 2.5 was considered as IR positive. Metabolic syndrome was classified according to NCEP ATP III guidelines. The remodeling index was defined as the ratio of the external elastic membrane (EEM) area at the lesion site to the EEM area at the proximal reference site.ResultsA total of 369 lesions were analyzed (161 lesions in HOMA-IR positive and 208 lesions in HOMA-IR negative). Remodeling index was significantly higher in the HOMA-IR positive group compared with the negative group (HOMA-IR positive vs. negative: 1.074 ± 0.109 vs. 1.042 ± 0.131, p = 0.013). There was a significant positive correlation between remodeling index and HOMA-IR (p = 0.010). Analysis of HOMA-IR according to remodeling groups showed increasing tendency of HOMA-IR, and it was statistically significant (p = 0.045). Multivariate analysis revealed that only HOMA-IR was an independent predictor of remodeling index (r = 0.166, p = 0.018).ConclusionIncreased IR estimated by HOMA-IR was significantly associated with a higher remodeling index and positive coronary artery remodeling.

Traumatic aortic regurgitation combined with descending aortic pseudo-aneurysm secondary to blunt chest trauma : online article - case report

Rupture of the aorta is a relatively rare complication of blunt chest trauma, and traumatic rupture of the aortic valve is even rarer. Even though both result from blunt chest trauma, the causative mechanisms of aortic valve injury differ from those of descending aortic rupture. There are no previous reports in the literature of simultaneous injuries to both the descending aorta and the aortic valve. We report a case of a 70-year-old man who presented with traumatic aortic regurgitation combined with traumatic pseudoaneurysm of the aortic isthmus following blunt chest trauma, and its successful repair with a hybrid surgical strategy.

Delayed embolisation of Amplatzer ASD closure device caused partial obstruction of left ventricular outflow tract : case report

A 54-year-old male presented with symptoms of dyspnoea, and oedema of the lower extremities. Transthoracic echocardiography (TTE) revealed secondum-type atrial septal defect (ASD). He successfully received a 30-mm Amplatzer ASD closure device percutaneously. Echocardiography immediately after the procedure and the next day showed a well-positioned device. He was discharged the next day on 100 mg aspirin daily and warfarinisation due to atrial fibrillation. A month later, he revisited the hospital due to recurrence of dyspnoea and a grade 2 systolic murmur was heard on the left parasternal border. A chest X-ray showed abnormal location of the closure device and TTE revealed re-appearance of the ASD and an embolised Amplatzer device in the left ventricular outflow tract (LVOT) with partial obstruction. He requested surgery to remove the Amplatzer device and received an ASD patch repair, tricuspid valve repair and modified Maze operation concurrently. He is now in routine follow up without any other complications.

Prognostic value of preoperative N-terminal pro-brain natriuretic peptide in non-cardiac surgery of elderly patients with normal left ventricular systolic function

We investigated the prognostic value of preoperative N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) in non‐cardiac surgery in elderly patients who showed normal left ventricular function on preoperative echocardiography.

Fatal delayed coronary artery perforation after coronary stent implantation.

Most type I and II perforations are predominately caused by hydrophilic and stiff wires, often presented in the delayed form, and do not require pericardial drainage or surgical interventions. However, we report a type III delayed coronary artery perforation at the site of stent implantation after intervention without any evidence of immediate perforations. To the best of our knowledge, this is the first case report of angiographic documentation and treatment of delayed coronary perforation at the site of stent, presented as a cardiac arrest.

A case of a resected benign myxoma-like hemorrhagic cyst, which later recurred as undifferentiated pleomorphic sarcoma in the left atrium

Rationale: An intracardiac cystic mass is a rare type of mass found in the left atrium. The differential diagnosis of an intracardiac cystic mass includes hydatid cysts, bronchogenic cysts, intracardiac varices, and hemorrhages in some tumor types, including myxoma. Patient concerns: We present the case of a 68-year-old woman who presented with episodic dyspnea. Diagnoses-Interventions-Outcomes: Transthoracic echocardiography (TTE) revealed the presence of a left atrial mass mimicking myxoma. However, in postoperative findings, it was determined that the mass was actually a hemorrhagic cyst. Eighteen months later, the patient presented with recurrent exertional dyspnea and TTE revealed the recurrence of a left atrial mass. Computed tomography showed that the mass extended into the right atrium, inferior vena cava, and coronary sinus. After re-operation, the final histological diagnosis was determined to be an undifferentiated pleomorphic sarcoma in the left atrium. Lessons: An intracardiac hemorrhagic cyst was suspected during the operation of a benign-looking LA mass. As such, we recommend that other rare etiologies be considered and more biopsies be performed when possible.

PROLONGED INFLAMMATION LED TO AORTIC VALVE SCLEROSIS: LONGITUDINAL PET/CT STUDY

Backgroud: Recent data shows evidence linking local aortic valve (AV) inflammation to subsequent AV calcification by PET/CT studies. We sought to test the hypothesis that prolonged inflammation is risk factors influences to aortic valve calcification. Methods: We identified 371 individuals (age 56

Serial measurements of neutrophil gelatinase-associated lipocalin: prognostic value in patients with ST-segment elevation myocardial infarction treated with a primary percutaneous coronary intervention

Background There are no previous data on serial changes in neutrophil gelatinase-associated lipocalin (NGAL) levels in ST-segment elevation myocardial infarction (STEMI) patients before and after a primary percutaneous coronary intervention (pPCI). The aim of the present study was to evaluate the prognostic value of serial NGAL measurements in patients with STEMI treated by pPCI. Materials and methods We identified 169 STEMI patients who underwent pPCI within 12 h of symptom onset and had plasma NGAL measurements before (pre-NGAL) and 6 h after (post-NGAL) pPCI. The primary endpoint was 30-day all-cause mortality, including cardiac death, whereas the secondary endpoint was the change in NGAL levels from before to after pPCI. Results The mean pre-NGAL and post-NGAL levels were 109.2±76.1 and 93.3±83.8 ng/ml, respectively. Thirty-day mortality occurred in 12 (7.1%) patients. In terms of changes in serial NGAL levels, post-NGAL levels were decreased in 132 (79%) patients. Patients with elevated post-NGAL levels showed increased mortality compared with patients with decreased post-NGAL levels (P=0.005). Multivariate analyses indicated that old age and high post-NGAL levels were independent risk factors for 30-day mortality. Conclusion In a large percentage of STEMI patients, plasma post-pPCI NGAL levels were decreased compared with pre-pPCI NGAL levels, even with the administration of potentially nephrotoxic contrast medium. Post-NGAL levels seemed to be superior to pre-NGAL levels for the prediction of 30-day mortality outcome.