Model order reduction techniques to identify submarining risk in a simplified human body model

This work investigates linear and non-linear parametric reduced order models (ROM) capable of replacing computationally expensive high-fidelity simulations of human body models (HBM) through a non-intrusive approach. Conventional crash simulation methods pose a computational barrier that restricts profound analyses such as uncertainty quantification, sensitivity analysis, or optimization studies. The non-intrusive framework couples dimensionality reduction techniques with machine learning-based surrogate models that yield a fast responding data-driven black-box model. A comparative study is made between linear and non-linear dimensionality reduction techniques. Both techniques report speed-ups of a few orders of magnitude with an accurate generalization of the design space. These accelerations make ROMs a valuable tool for engineers.

Role of β-blockers in the cardiovascular disease continuum: a collaborative Delphi survey-based consensus from Asia-Pacific

OBJECTIVE

This Delphi method of consensus was designed to develop scientific statements for β-blockers in the continuum of cardiovascular diseases with a special focus on the role of bisoprolol.

METHODS

Eleven experienced cardiologists from across the Asia-Pacific countries participated in two rounds of the survey. In the first round, experts were asked to rate agreement/disagreement with 35 statements across seven domains regarding the use of β-blockers for treating hypertension, heart failure, coronary artery diseases, co-morbidities, as well as their safety profile, usage pattern, and pharmacokinetic variability. A consensus for a statement could be reached with >70% agreement.

RESULTS

Except for seven statements, all attained consensus in the first round. In the second round that was conducted virtually, the experts re-appraised their ratings for the seven statements along with a critical appraisal of two additional statements that were suggested by experts in the preceding round. At the end of the second round, the final version included 36 statements (34 original statements, two statements suggested by experts, and the omission of one statement that did not attain consensus). The final version of statements in the second round was disseminated among experts for their approval followed by manuscript development.

CONCLUSION

Attainment of consensus for almost all statements reconfirms the clinical benefits of β-blockers, particularly β1-selective blockers for the entire spectrum of cardiovascular diseases.

P1445 DORv and window: a case of an uncorrected double outlet right ventricle with d-transposition of great arteries with concomitant aortopulmonary window in a 31-year-old female

Funding Acknowledgements

none

Double outlet right ventricle (DORV) is a rare type of ventriculo-arterial connection occurring in about 1-3% of congenital heart defects. Moreover, transposition of the great arteries, wherein the aorta is anterior and to the right of the pulmonary artery (D-TGA), accounts for only 26% of cases of DORV. An aortopulmonary window, on the other hand, represents approximately only 0.2% of all congenital cardiac lesions. A case of DORV with D-TGA and pulmonary stenosis with a concomitant aortopulmonary window has never been reported, particularly in an adult in the third decade of life and without any history of surgical repair.

We present the case of a 31-year-old female who had sought consult for left-sided weakness. On physical examination, a grade IV/VI systolic murmur was heard at the left anterior chest and cyanosis of the digits of the upper and lower extremities were noted. Transthoracic echocardiogram revealed a non-restrictive ventricular septal defect (VSD) and segmental approach showed atrial and visceral situs solitus, levocardia, and atrioventricular concordance. However, there was ventriculoarterial discordance with fusiform aneurysmal dilatation of the aorta, which was noted to be at the right of and anterior to the pulmonary artery. Both great vessels arose from the right ventricle. Other echocardiographic findings included dilated right atrium, dilated and hypertrophied right ventricle with volume and pressure overload, global left ventricular hypokinesia with mild systolic dysfunction, and moderate to severe aortic regurgitation. The above complex congenital anomalies were confirmed via transesophageal echocardiogram and cardiac magnetic resonance imaging (MRI). Furthermore, pulmonary valve stenosis and aortopulmonary window, that was 3.5 centimeters in length located at the level of the proximal ascending aorta and main pulmonary artery, were seen on the MRI.

Various cardiac imaging modalities aided in cinching the diagnosis for this very rare complex congenital case in an adult reaching the third decade of life. Palliative care was deemed best for this patient due to the severity of her cardiac condition.

Abstract P1445 Figure 1.

Idiopathic chronic constipation is associated with decreased colonic vasoactive intestinal peptide

To investigate the reported association between idiopathic chronic constipation and morphologic abnormalities of enteric nerves, we measured the concentrations of six neuropeptides, vasoactive intestinal peptide, peptide histidine-methionine, substance P, methionine5-enkephalin, neuropeptide Y, and the bombesinlike intestinal peptides, in descending colon from 4 patients with idiopathic chronic constipation. Decreased concentrations of vasoactive intestinal peptide (707 +/- 112 ng/g wet tissue) and peptide histidine-methionine (543 +/- 58 ng/g) were found in the muscularis externa obtained from constipated patients compared with normal concentrations (40 patients) of vasoactive intestinal peptide (1199 +/- 47 ng/g) and peptide histidine-methionine (815 +/- 45 ng/g). Vasoactive intestinal peptide was identified by immunocytochemistry in nerve fibers within the circular smooth muscle layer of descending colon obtained from 6 control patients, but not in nerve fibers within the circular smooth muscle of descending colon obtained from 3 patients with idiopathic chronic constipation. By contrast, the distribution of immunoreactive met5-enkephalin was similar in normal descending colon and in descending colon obtained from patients with idiopathic chronic constipation. Decreased colonic concentrations of vasoactive intestinal peptide (a candidate nonadrenergic, noncholinergic inhibitory neurotransmitter) may be associated with diminution of inhibitory innervation of colonic circular smooth muscle in some patients with idiopathic chronic constipation.