Framework for patient-specific simulation of hemodynamics in heart failure with counterpulsation support

Despite being responsible for half of heart failure-related hospitalizations, heart failure with preserved ejection fraction (HFpEF) has limited evidence-based treatment options. Currently, a substantial clinical issue is that the disease etiology is very heterogenous with no patient-specific treatment options. Modeling can provide a framework for evaluating alternative treatment strategies. Counterpulsation strategies have the capacity to improve left ventricular diastolic filling by reducing systolic blood pressure and augmenting the diastolic pressure that drives coronary perfusion. Here, we propose a framework for testing the effectiveness of a soft robotic extra-aortic counterpulsation strategy using a patient-specific closed-loop hemodynamic lumped parameter model of a patient with HFpEF. The soft robotic device prototype was characterized experimentally in a physiologically pressurized (50–150 mmHg) soft silicone vessel and modeled as a combination of a pressure source and a capacitance. The patient-specific model was created using open-source software and validated against hemodynamics obtained by imaging of a patient (male, 87 years, HR = 60 bpm) with HFpEF. The impact of actuation timing on the flows and pressures as well as systolic function was analyzed. Good agreement between the patient-specific model and patient data was achieved with relative errors below 5% in all categories except for the diastolic aortic root pressure and the end systolic volume. The most effective reduction in systolic pressure compared to baseline (147 vs. 141 mmHg) was achieved when actuating 350 ms before systole. In this case, flow splits were preserved, and cardiac output was increased (5.17 vs. 5.34 L/min), resulting in increased blood flow to the coronaries (0.15 vs. 0.16 L/min). Both arterial elastance (0.77 vs. 0.74 mmHg/mL) and stroke work (11.8 vs. 10.6 kJ) were decreased compared to baseline, however left atrial pressure increased (11.2 vs. 11.5 mmHg). A higher actuation pressure is associated with higher systolic pressure reduction and slightly higher coronary flow. The soft robotic device prototype achieves reduced systolic pressure, reduced stroke work, slightly increased coronary perfusion, but increased left atrial pressures in HFpEF patients. In future work, the framework could include additional physiological mechanisms, a larger patient cohort with HFpEF, and testing against clinically used devices.

Modeling of Radiative Properties of Polystyrene Foams Containing IR-Opacifiers

The addition of opacifiers in foams considerably reduces the radiative thermal conductivity and consequently enhances the insulation performance of the foams. In this work two different methods were developed to calculate the spectral specific extinction coefficient of opacified extruded polystyrene (XPS) foam material. Cell morphology and thermal conductivity of two identical XPS-foams, one opacified with 3 wt% carbon black as opacifier and one without opacifier, were thoroughly characterized. The experimental results were in a good agreement with the theoretical results obtained from two different computing techniques. These methods allow a good prediction of the specific extinction coefficient of arbitrary opacified foam material.

A new classification of peri-articular heterotopic ossification of the hip associated with neurological injury: 3D CT scan assessment and intra-operative findings

In this paper we propose a new classification of neurogenic peri-articular heterotopic ossification (HO) of the hip based on three-dimensional (3D) CT, with the aim of improving pre-operative planning for its excision. A total of 55 patients (73 hips) with clinically significant HO after either traumatic brain or spinal cord injury were assessed by 3D-CT scanning, and the results compared with the intra-operative findings. At operation, the gross pathological anatomy of the HO as identified by 3D-CT imaging was confirmed as affecting the peri-articular hip muscles to a greater or lesser extent. We identified seven patterns of involvement: four basic (anterior, medial, posterior and lateral) and three mixed (anteromedial, posterolateral and circumferential). Excellent intra- and inter-observer agreement, with kappa values > 0.8, confirmed the reproducibility of the classification system. We describe the different surgical approaches used to excise the HO which were guided by the 3D-CT findings. Resection was always successful. 3D-CT imaging, complemented in some cases by angiography, allows the surgeon to define the 3D anatomy of the HO accurately and to plan its surgical excision with precision.

Fragility fractures of the pelvis: treatment and preliminary results

BACKGROUND

With increasing life expectancy, fragility fractures of the pelvic ring (FFP) are becoming frequent. In elderly, osteoporosis leads to a decrease of bone strength and resistance to the ligament's traction; this represents the most important difference between FFP and fractures in young patients. Usually, these fractures are underestimated and treatment is often conservative.

AIMS

To evaluate clinical and surgical outcomes of surgically treated patients with FFP.

METHODS

We retrospectively enrolled 14 patients, in our Trauma Center, underwent surgery procedures for FFP between 2012 and 2014. All patients attended clinical and radiological investigation at 1, 3, and 6 months postoperatively and every year after surgery with a mean follow-up of 22 months.

RESULTS

At 6-month follow-up, 11 patients resulted asymptomatic: able to maintain standing position and walk without crunches. Two patients were able to walk with one crunch. The patient with history of previous acetabular fracture walks with two crunches and is still waiting for total hip arthroplasty.

DISCUSSION

The compromised health status and the diminished bone-healing capacity, in elderly, decrease chances for a good clinical outcome. In literature, many authors suggest that mortality rate in patients with FFP is similar to those with hip fracture. Diagnosis of FFP is very important: these fractures are highly disabling in elderly and can lead to displacement and instability. For these reasons, correct diagnosis and well-conduct preoperative plan are necessary to improve stability of fractures and support bone healing. After diagnosis, an anti-osteoporotic treatment is indicated to improve bone quality and bone healing.

CONCLUSIONS

Our study shows encouraging results and demonstrates that minimally or less invasive osteosynthesis technique could lead to good outcome in these patients.

Intra-abdominal versus free-loop portion Doppler analysis of the umbilical artery: the importance of the choice

AIM

The aim of this study was to assess the variations in Doppler indexes along the length of the cord from the intra-abdominal portion (IAP) to the free loop portion (FLP) of the umbilical artery (UA).

METHODS

UA blood flow velocities were measured at the IAP and FLP in 100 low-risk singleton pregnancies. The peak systolic velocity (PSV), end-diastolic velocity, pulsatility index (PI), resistance index (RI), PS/ED ratio and Delta value (Δ) were calculated. at each site of sampling and were compared.

RESULTS

PI and RI of the IAP were greater versus the FLP. UA blood velocities increased with gestational age and the PSV at the IAP showed different development compared to other sites, increasing from 20 to 30-32 weeks and then decreasing until term. The PSV value was greater in the IAP from 20 until 36 weeks. There were not significant differences in EDV values between the two sites. The Δ PI in IAP remained constantly greater than ~0.2 at all gestational ages.

CONCLUSION

UA Doppler parameters vary significantly at different locations, showing the greater value in the IAP. The IAP site is in a fixed anatomical position, therefore potentially reproducible. This potential advantage is very important in cases of severe growth restriction and in monoamniotic twins.

Surgical treatment of unstable pelvic fracture in children: long term results

Paediatric pelvic fractures are rare lesions. In the literature still controversy exists regarding the management of these injuries. The sequelae of these types of lesions has been described. We report the management and long term outcome of 8 patients with paediatric pelvic fractures treated in our institution. Associated injuries to the Risser's growth nuclei are described that has not been previously reported. Anatomical reduction of the displaced fracture should be considered to minimise the risk of long term functional impairment.

[''Prepidil versus Propess'': pharmacological induction of labour with dinoprostone]

AIM

The aim of the study was to evaluate the effectiveness and safety of the two different pharmaceutical preparations of dinoprostone: ''Prepidil vs Propess'', in patients with medical and/or obstetrical indications to pharmaceutical induction of labour.

METHODS

A retrospective analysis was carried out on 144 patients (82 with Propess vs 62 with Prepidil).

INDICATIONS

post-term pregnancy, premature rupture of membranes (PROM), gestational diabetes, gestational-chronic hypertension, intrauterine growth restriction (IUGR),others (fetal macrosomia, oligohydramnios).

RESULTS

The groups were homogenous regarding: age, parity, weeks of amenorrhea, Bishop score and indication to induction. Both pharmaceutical preparations of dinoprostone (Prepidil vs Propess) are effective and safe; there are some differences not statistically significant (P>0.01) regarding the percentage of spontaneous deliveries: 61.5% vs 63%, interval from induction to delivery 24.53 vs 20.45 h, number of inductions 1.35 vs 1.15 and neonatal outcome (Apgar scores at 1 and 5 min). A case of serious hyperstimulation with hysterectomy post-delivery after induction with Prepidi was observed.

CONCLUSION

A greater use of Propess, especially in patients with PROM, is suggested; Propess has determined a higher percentage of spontaneous deliveries, a shorter interval from induction to delivery and less risks for the mother. It is in fact possible to remove the device easily and safely in case of complication.

[Some clinical aspects of celiac disease (author's transl)]

220 jejunal biopsies have been performed in 146 children. Out of these, thirteen have been recognized as suffering from celiac disease. Furthermore, the possibility of celiac disease being associated with other gastrointestinal disorders, either of the stomach or of the sigma and rectum has been considered. Any explanation for this association can only be hypothetical, because the pathogenesis of celiac disease needs further study.