Hemodynamic-based virtual surgery design of double-patch repair for pulmonary arterioplasty in tetralogy of Fallot.

BACKGROUND AND OBJECTIVE: Surgical correction of pulmonary artery stenosis (PAS) is essential to the prognosis of patients with tetralogy of Fallot (TOF). The double-patch method of pulmonary arterioplasty is usually applied in case of multiple stenosis in TOF patients' pulmonary artery (PA) and when PAS cannot be relieved by the single-patch method. The surgical planning for the double-patch design remains challenging. The purpose of this study is to investigate the double-patch design with different angulations between the left pulmonary artery (LPA) and the right pulmonary artery (RPA), and to understand postoperative hemodynamic alterations by the application of computer-aided design (CAD) and computational fluid dynamics (CFD) techniques. METHODS: The three-dimensional model of the PA was reconstructed based on preoperative computed tomography imaging data obtained from the patient with TOF. Three postoperative models with different designs of double-patch were created by "virtual surgery" using the CAD technique. Double-Patch 120 Model was created with double patches implanted in the main pulmonary artery (MPA) and the PA bifurcation and without changing the spatial position of PA. The angulation between the LPA and the RPA was defined as θ, which equaled to 120° in Pre-Operative Model and Double-Patch 120 Model. Based on Double-Patch 120 Model, Double-Patch 110 Model and Double-Patch 130 Model were generated with θ equaled to 110° and 130°, respectively. Combined with CFD, the differences of velocity streamlines, wall shear stress (WSS), flow distribution ratio (FDR), and energy loss (EL) were compared to analyze postoperative pulmonary flow characteristics. RESULTS: The values of velocity and WSS decreased significantly after virtual surgery. Obvious vortices and swirling flows were observed downstream of the stenosis of RPA and LPA in Pre-Operative Model, while fewer vortices developed along the anterior wall of the expanded lumens of RPA, especially in Double-Patch 110 Model. With the relief of PAS, two relatively higher WSS regions were observed at the posterior walls of RPA and LPA. The maximum WSS values in these regions of Double-Patch 110 Model were lower than those in Double-Patch 120 Model and Double-Patch 130 Model. Furthermore, the FDRs were elevated and the ELs were greatly reduced. It was found that Double-Patch 110 Model with the angulation between the LPA and the RPA equaled to 110° showed relatively better properties of hemodynamics than other models. CONCLUSIONS: The angulation between the LPA and the RPA is an important factor that should be integrated in the double-patch design for TOF repair. Virtual surgery based on patient-specific vascular model and computational hemodynamics can be used to provide assistance for individualized surgical planning of double-patch arterioplasty.

Effects of Patent Ductus Arteriosus on the Hemodynamics of Modified Blalock-Taussig Shunt Based on Patient-Specific Simulation.

The question of preserving the patent ductus arteriosus (PDA) during the modified Blalock-Taussig shunt (MBTS) procedure remains controversial. The goal of this study was to investigate the effects of the PDA on the flow features of the MBTS to help with preoperative surgery design and postoperative prediction. In this study, a patient with pulmonary atresia and PDA was included. A patient-specific three-dimensional model was reconstructed, and virtual surgeries of shunt insertion and ductus ligation were performed using computer-aided design. Computational fluid dynamics was utilized to analyze the hemodynamic parameters of varied models based on the patient-specific anatomy and physiological data. The preservation of the PDA competitively reduced the shunt flow but increased total pulmonary perfusion. The shunt flow and ductal flow collided, causing significant and complicated turbulence in the pulmonary artery where low wall shear stress, high oscillatory shear index, and high relative residence time were distributed. The highest energy loss was found when the PDA was preserved. The preservation of PDA is not recommended during MBTS procedures because it negatively influences hemodynamics. This may lead to pulmonary overperfusion, inadequate systemic perfusion, and a heavier cardiac burden, thus increasing the risk of heart failure. Also, it seems to bring no benefit in terms of reducing the risk for thrombosis.

Medical Image-Based Hemodynamic Analyses in a Study of the Pulmonary Artery in Children With Pulmonary Hypertension Related to Congenital Heart Disease.

Objective: Pulmonary hypertension related to congenital heart disease (PH-CHD) is a devastating disease caused by hemodynamic disorders. Previous hemodynamic research in PH-CHD mainly focused on wall shear stress (WSS). However, energy loss (EL) is a vital parameter in evaluation of hemodynamic status. We investigated if EL of the pulmonary artery (PA) is a potential biomechanical marker for comprehensive assessment of PH-CHD. Materials and Methods: Ten PH-CHD patients and 10 age-matched controls were enrolled. Subject-specific 3-D PA models were reconstructed based on computed tomography. Transient flow, WSS, and EL in the PA were calculated using non-invasive computational fluid dynamics. The relationship between body surface area (BSA)-normalized EL ( E . ) and PA morphology and PA flow were analyzed. Results: Morphologic analysis indicated that the BSA-normalized main PA (MPA) diameter (DMPAnorm), MPA/aorta diameter ratio (DMPA/DAO), and MPA/(left PA + right PA) [DMPA/D(LPA+RPA)] diameter ratio were significantly larger in PH-CHD patients. Hemodynamic results showed that the velocity of the PA branches was higher in PH-CHD patients, in whom PA flow rate usually increased. WSS in the MPA was lower and E . was higher in PH-CHD patients. E . was positively correlated with DMPAnorm, DMPA/DAO, and DMPA/D(LPA+RPA) ratios and the flow rate in the PA. E . was a sensitive index for the diagnosis of PH-CHD. Conclusion: E . is a potential biomechanical marker for PH-CHD assessment. This hemodynamic parameter may lead to new directions for revealing the potential pathophysiologic mechanism of PH-CHD.

[Differences of bone augmentation in patients with different bone defects by extraction site preservation].

PURPOSE: To explore the difference of bone augmentation in patients with different bone defects by extraction site preservation. METHODS: From January 2017 to June 2019, 85 patients with dental implants treated in Hefei Second People's Hospital were enrolled and divided into the experimental group (43 cases) and the control group (42 cases) according to random number table method. Patients in the experimental group received extraction site preservation, while patients in the control group underwent routine tooth extraction. The two groups were further divided into one-wall group (remaining one wall of the alveolar socket after surgery), two-wall group (remaining two walls), three-wall group (remaining three wall), and four-wall group (remaining four walls). Postoperative pain, wound healing, and infection were recorded. Cone-beam CT (CBCT) was performed immediately and 6 months after surgery to detect alveolar bone height, bone width, bone width recovery rate, etc. SPSS 22.0 software package was used for statistical analysis. RESULTS: There was no significant difference in pain between the two groups after 24 hours (P>0.05). All implants healed well after 7 days, and no wound infection or bone infection occurred 6 months after operation. There was no significant difference in buccal bone volume of alveolar ridge (BV) and lingual volume (LV) before surgery between the two groups (P>0.05). BV and LV in the experimental group increased after treatment, and the increase in one- and two-wall subgroups was significantly higher than that in three- and four-wall subgroups. BV and LV in the control group decreased, the differences between the subgroups were statistically significant (P<0.05). BV and LV increased in both groups after operation, but significantly higher in the experimental group than in the control group. The increase in bone height in one- and two-wall subgroups was significantly higher than that in three- and four-wall groups (P<0.05). Bone width of all subgroups in the experimental group increased, but decreased in the control group. The increase of bone width in the experimental group was significantly different from the control group(P<0.05). In the experimental group, the increase in bone width in one- and two-wall groups was significantly higher than that in three-wall group, and the decrease in bone width in one- and two-wall group in the control group was significantly less than that in three- and four-wall group(P<0.05). The average recovery rate of bone width in the experimental group was significantly higher than that in the control group. The average recovery rate of bone width in one- and two-wall group in the experimental group was significantly higher than that in the control group(P<0.05), while there was no significant difference in the recovery rate from the control group(P>0.05). The change of bone width at 70% of root length in the same group was significantly smaller than that at 50% and 30% of root length (P<0.05). CONCLUSIONS: Extraction site preservation after tooth extraction can relieve alveolar bone resorption and maintain bone mass in contrast to conventional tooth extraction. The smaller the bone defect, the better the bone mass recovery effect.

Reliability of information about the use of antiepileptic drugs during pregnancy from three major web search engines in China.

OBJECTIVES: The objective of this study was to assess the reliability of online information, as provided by three major search engines in China, about the usage of antiepileptic drugs (AEDs) during pregnancy. METHOD: Over eight weeks, six physicians conducted a literature search on six computers and six smartphones at a frequency of once per week. During each web search on each computer and smartphone, three major search engines in China were used, namely, Baidu, Sogou and 360. The search terms used were a combination of words, including one AED name (valproate/oxcarbazepine/levetiracetam/lamotrigine) and one Chinese word ("huaiyun" or "renshen", which means pregnancy in Chinese). The top ten websites retrieved from each search were recorded. After the content of each website was evaluated, the sites were categorized into 9 types. Meanwhile, commercial advertisements on each web page were also registered. RESULTS: A total of 16,411 search results were assessed. After excluding the redundant web pages, 4840 search results were included in the data analysis. Only 12.05% of the search results were reliable, 47.75% were partly reliable, and 40.21% were unreliable. A total of 4139 (85.52%) webpages contained commercial advertisements. The results from a multivariate analysis suggested that websites with no advertisements and professional websites have an independent positive impact on reliability. CONCLUSION: Overall, little information on AED usage during pregnancy provided by major search engines in China was reliable. PRACTICE IMPLICATIONS: Accurate and professional online information for female patients with epilepsy should be provided through major efforts by the government, search engine companies, professional websites and epilepsy physicians.