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Although acute cardiac tamponade is one of the major problems in clinical practice, a suitable animal model is still lacking. We tried to create acute cardiac tamponade in macaques by echo-guided catheter manipulation. A 13-year-old male macaque was anesthetized, and a long sheath was inserted into the left ventricle via the left carotid artery under the guidance of transthoracic echocardiography. The sheath was then inserted into the orifice of the left coronary artery to perforate the proximal site of the left anterior descending branch. A cardiac tamponade was successfully created. Injection of diluted contrast agent into the pericardial space via a catheter made it possible to clearly distinguish between the hemopericardium and the surrounding tissues on postmortem computed tomography. This procedure did not need an X-ray imaging system during catheterization. Our present model would help us examine the intrathoracic organs in the presence of acute cardiac tamponade.

type:Journal Article, Background: Paradoxical low-flow, low-gradient (PLF-LG) aortic stenosis (AS) is associated with poor prognosis in patients undergoing transcatheter aortic valve implantation (TAVI). This study aimed to verify the conventional criteria of PLF-LG AS (left ventricular ejection fraction [LVEF] > 50%, mean aortic valve pressure gradient [AVPG] < 40 mm Hg and stroke volume index [SVI] < 35 ml/m2 by measuring Doppler method) compatible for predicting prognosis in patients undergoing TAVI., Materials and methods: A total of 128 consecutive patients who underwent TAVI for AS with LVEF > 50% were enrolled. The primary endpoint was the hospital readmission due to heart failure (HRHF) and the secondary endpoint was all-cause mortality after hospital discharge. The patients were classified by both the conventional criteria of PLF-LG AS and the proposal criteria of PLF-LG AS if mean aortic valve pressure gradient (AVPG) < 40 mmHg and SVI by measuring Simpson's method < cut off value based on the ROC curve for predicting HRHF., Results: According to the conventional criteria, only 6 patients were diagnosed with PLF-LG AS. However, according to the proposal criteria, 16 patients were diagnosed with PLF-LG AS. Fourteen patients developed HRHF during the follow-up period after TAVI. Based on the ROC curves, SVI by measuring Simpson's method (cut off value = 25 ml/m2) had higher sensitivity and specificity for predicting HRHF (AUC = 0.74, p = 0.0013) than SVI by measuring Doppler method (AUC = 0.63, p = 0.045). The multivariate analysis revealed that PLF-LG AS defined by the proposal criteria (HR: 5.25; 95% CI: 1.60–17.16; p = 0.0073) but not by the conventional criteria was independently associated with HRHF. PLF-LG AS defined by the conventional criteria and the proposal criteria were not associated with all-cause mortality in the univariate analysis., Conclusions: Our results demonstrated that new criteria of PLF-LG AS defined as SVI < 25 ml/m2 measured by Simpson's method could predict HRHF in patients with severe AS who underwent TAVI.