Rescue computed tomography-guided drainage of a giant mediastinal mature teratoma causing airway obstruction prior to surgical resection: a case report.

BACKGROUND: Giant mediastinal mature teratomas may cause airway obstruction or decreased venous return due to the mass effect. Preoperative stabilization of the respiratory and circulatory systems is important for perioperative management to safely perform surgery, including general anesthesia. However, to the best of our knowledge, there are only a few reports regarding the preoperative computed tomography (CT)-guided drainage of mediastinal tumors. CASE PRESENTATION: A 30-year-old woman was admitted to the emergency room with sudden dyspnea. CT findings revealed a giant cystic mass in the anterior mediastinum compressing the trachea and the right main bronchus. The patient was intubated and CT-guided drainage of the fluid content of the cyst was performed to decompress the airway obstruction. Thereafter, the mediastinal tumor was resected during elective surgery and pathologically diagnosed as a mature teratoma. CONCLUSIONS: Rescue preoperative CT-guided drainage of a giant mediastinal mature teratoma allowed safe general anesthesia and surgery by releasing the airway obstruction.

Carbon monoxide combined with artificial blood cells acts as an antioxidant for tissues thermally-damaged by dye laser irradiation.

Artificial red blood cells [i.e., hemoglobin vesicles (HbVs)] can be used as photosensitizers in pulsed-dye laser (PDL) treatment for port wine stains in animal models. Small HbVs are distributed in the vicinity of the endothelial cells of the blood vessels. In our previous in vivo experiments, both HbVs and red blood cells absorbed photons of the laser and generated heat, contributing to removal of very small blood vessels and large deeper subcutaneous blood vessels with PDL irradiation. Herein, we tested carbon monoxide-bound HbVs (CO-HbVs) that would produce heat energy while releasing CO in vessels after dye laser irradiation in a rabbit auricle model. We conducted this experiment to confirm secondary progression of thermal injury being reduced with the antioxidative property of CO. We histopathologically evaluated the damages to the large vessels and surrounding dermal tissue following PDL irradiation alone or subsequent to the intravenous injection of the qualified HbVs. The soft tissue damages were graded on a five-point scale and compared statistically. Intravenous CO-HbVs significantly reduced damage to the surrounding tissue after subsequent PDL irradiation; however, the degree of damage to the larger vessel wall resulted in a variety of changes, including a slight increase in our histopathological grades. This beneficial effect in dye laser treatment for port wine stains may be the result of the antioxidative property of CO against free radicals in the zone of stasis that may still be theoretically viable in burns. This effect of CO protecting tissues from thermal damage is consistent with previous reports of CO as a reducing agent. If the reducing agent can be delivered directly to the affected area immediately after the burn injury, even in a small amount, the complex inflammatory cascade may be reduced and unnecessary inflammation after laser treatment that lowers the patient's quality of life can be avoided.

Retrograde in situ branched stent grafting for a patient with type V thoracoabdominal aortic aneurysm.

We have presented the case of a 76-year-old patient with a type V thoracoabdominal aortic aneurysm treated by retrograde in situ branched stent grafting to the superior mesenteric artery (SMA). Via a 9-cm, median laparotomy, a percutaneous transhepatic gallbladder drainage needle was inserted from the distal part of the first jejunal artery to the origin of the SMA. After stent graft placement into the aorta, the graft was retrogradely punctured using the percutaneous transhepatic gallbladder drainage needle. The SMA ischemic time was 6 minutes. The puncture site was dilated, and a small, covered stent was deployed. Postoperative computed tomography scanning showed no endoleak with sac regression.

Rapeseed (canola) oil aggravates metabolic syndrome-like conditions in male but not in female stroke-prone spontaneously hypertensive rats (SHRSP).

This study was conducted to investigate whether or not there are sex differences in canola oil (CAN)-induced adverse events in the rat and to understand the involvement and the role of testosterone in those events, including life-shortening. Stroke-prone spontaneously hypertensive rats (SHRSP) of both sexes were fed a diet containing 10 wt/wt% soybean oil (SOY, control) or CAN as the sole dietary fat. The survival of the males fed the CAN diet was significantly shorter than that of those fed the SOY diet. In contrast, the survival of the females was not affected by CAN. The males fed the CAN diet showed elevated blood pressure, thrombopenia and insulin-tolerance, which are major symptoms of metabolic syndrome, whereas such changes by the CAN diet were not found in the females. Plasma testosterone was significantly lower in animals of both sexes fed the CAN diet than in those fed the SOY diet, but interestingly, the lowered testosterone was accompanied by a marked increase in plasma aldosterone only in the males. These results demonstrate significant sex differences in CAN-toxicity and suggest that those sex differences may be attributable to the increased aldosterone level, which triggers aggravation of the genetic diseases specific to SHRSP, that is, metabolic syndrome-like conditions, but only in the males. The present results also suggest that testosterone may negatively regulate aldosterone production in the physiology of the males, and the inhibition of that negative regulation caused by the CAN diet is one of the possible causes of the adverse events.

Directing a dispersion cannula tip toward the aortic root during thoracic aortic arch surgery does not adversely affect cardiac function.

INTRODUCTION: Neurologic complications of open thoracic aortic surgery are devastating problems in patients with severely diseased aortas. This study aimed to clarify whether directing the aortic cannula tip toward the aortic root affects the postoperative cardiac function in patients undergoing open thoracic aortic surgery. METHODS: A total of 16 patients who underwent total or partial arch replacement between January 2014 and April 2019 were enrolled and divided into two groups. Ascending aorta perfusion was performed by placing the cannula tip toward the aortic root (reversed direction group, seven patients) or toward the aortic arch (standard direction group, nine patients). Intraoperative and perioperative data, including mortality, morbidity, and postoperative cardiac function, were compared between the groups. RESULTS: There were no hospital deaths or stroke events in either group. The aortic cross-clamping time was 102.4 ± 20.3 minutes in the reversed direction group and 87.1 ± 9.9 minutes in the standard direction group (p = 0.049). Furthermore, the intubation time was 28.4 ± 12.9 hours in the reversed direction group and 12.4 ± 6.8 hours in the standard direction group (p = 0.022). Both times were significantly longer in the reverse direction group. Postoperative serum creatine kinase-MB levels were significantly lower in the reversed direction group (6.2 ± 3.3 U/L vs 13.3 ± 4.8 U/L, respectively, p = 0.006). The cardiac output and cardiac index did not significantly differ. CONCLUSIONS: Directing the aortic cannula tip toward the aortic root does not adversely affect the postoperative cardiac function after aortic arch surgery.

Left atrial geometry in an ovine ischemic mitral regurgitation model: implications for transcatheter mitral valve replacement devices with a left atrial anchoring mechanism.

BACKGROUND: Transcatheter mitral valve replacement (TMVR) is a challenging, but promising minimally invasive treatment option for patients with mitral valve disease. Depending on the anchoring mechanism, complications such as mitral leaflet or chordal disruption, aortic valve disruption or left ventricular outflow tract obstruction may occur. Supra-annular devices only anchor at the left atrial (LA) level with a low risk of these complications. For development of transcatheter valves based on LA anchoring, animal feasibility studies are required. In this study we sought to describe LA systolic and diastolic geometry in an ovine ischemic mitral regurgitation (IMR) model using magnetic resonance imaging (MRI) and echocardiography in order to facilitate future research focusing on TMVR device development for (I)MR with LA anchoring mechanisms. METHODS: A group of 10 adult male Dorsett sheep underwent a left lateral thoracotomy. Posterolateral myocardial infarction was created by ligation of the left circumflex coronary artery, the obtuse marginal and diagonal branches. MRI and echocardiography were performed at baseline and 8 weeks after myocardial infarction (MI). RESULTS: Six animals survived to 8 weeks follow-up. All animals had grade 2 + or higher IMR 8 weeks post-MI. All LA geometric parameters did not change significantly 8 weeks post-MI compared to baseline. Diastolic and systolic interpapillary muscle distance increased significantly 8 weeks post-MI. CONCLUSIONS: Systolic and diastolic LA geometry do not change significantly in the presence of grade 2 + or higher IMR 8 weeks post-MI. These findings help facilitate future tailored TMVR device development with LA anchoring mechanisms.

Fully hydrogenated canola oil extends lifespan in stroke-prone spontaneously hypertensive rats.

BACKGROUND: Canola oil (Can) and several vegetable oils shorten the lifespan of stroke-prone spontaneously hypertensive rats (SHRSP). Although similar lifespan shortening has been reported for partially hydrogenated Can, the efficacy of fully hydrogenated oils on the lifespan remains unknown. The present study aimed to investigate the lifespan of SHRSP fed diets containing 10 % (w/w) of fully hydrogenated Can (FHCO) or other oils. METHODS: Survival test: Upon weaning, male SHRSP were fed a basal diet for rodents mixed with one of the test oils -i.e., FHCO, Can, lard (Lrd), and palm oil (Plm) throughout the experiment. The animals could freely access the diet and drinking water (water containing 1 % NaCl), and their body weight, food intake, and lifespan were recorded. Biochemical analysis test: Male SHRSP were fed a test diet with either FHCO, Can, or soybean oil (Soy) under the same condition, except to emphasize effects of fat, that no NaCl loading was applied. Soy was used as a fat source in the basal diet and was set the control group. Blood pressures was checked every 2 weeks, and serum fat levels and histological analyses of the brain and kidney were examined after 7 or 12 weeks of feeding. RESULTS: During the survival study period, the food consumption of FHCO-fed rats significantly increased (15-20 % w/w) compared with that of rats fed any other oil. However, the body weight gain in the FHCO group was significantly less (10-12 %) than that in the control group at 9-11 weeks old. The FHCO (> 180 days) intervention had the greatest effect on lifespan, followed by the Lrd (115 ± 6 days), Plm (101 ± 2 days), and Can (94 ± 3 days) diets. FHCO remarkably decreased the serum cholesterol level compared with Can and the systolic blood pressure from 12 to 16 weeks of age. In addition, while some rats in the Can group exhibited brain hemorrhaging and renal dysfunction at 16 weeks old, no symptoms were observed in the FHCO group. CONCLUSION: This current study suggests that complete hydrogenation decreases the toxicity of Can and even prolongs the lifespan in SHRSP.

The results of aortic arch replacement using antegrade cerebral perfusion in haemodialysis patients: analysis of the Japan cardiovascular surgery database.

OBJECTIVES: There have been limited data available regarding aortic arch replacement in dialysis patients. The purpose of this study was to examine real-world data and to determine the impact of preoperative dialysis status and other risks on surgical aortic arch replacement using the Japan Cardiovascular Surgery Database. METHODS: A total of 5044 patients who underwent elective, isolated aortic arch replacement using antegrade cerebral perfusion during 2014-2017 were eligible for the study. Of these, 89 patients received haemodialysis preoperatively. The patients were divided into 6 groups according to their preoperative estimated glomerular filtration rate and dialysis status for comparison. Preoperative and postoperative data were examined using a multivariable regression model. RESULTS: The overall surgical mortality rates of non-Chronic Kidney Disease (CKD) (estimated glomerular filtration rate >60 ml/min/1.73 m2), stage 3A, stage 3B, stage 4, stage 5 CKD and dialysis patients were 2.6%, 3.1%, 6.8%, 11.6%, 16.7% and 13.5%, respectively. After risk adjustment, dialysis was shown to be strongly associated with surgical mortality (odds ratio 4.39 and 95% confidence interval 2.22-8.72) and have a trend to be associated with postoperative stroke (odds ratio 2.02, 95% confidence interval 1.00-4.10, P = 0.051) when compared to the non-CKD group. As predictors of mortality, male sex, peripheral arterial disease, preoperative liver dysfunction and impaired left ventricular function were identified. CONCLUSIONS: The Japanese nationwide database revealed the outcomes of aortic arch replacement in dialysis patients. Appropriate counselling and an alternative strategy should be considered for such patients with multiple risks for mortality.

Artificial red blood cells increase large vessel wall damage and decrease surrounding dermal tissue damage in a rabbit auricle model after subsequent flashlamp-pumped pulsed-dye laser treatment.

Artificial red blood cells (i.e. hemoglobin [Hb] vesicles [Hb-Vs]) function effectively as photosensitizers in flashlamp-pumped pulsed-dye laser (PDL) treatment for port-wine stains in animal models. Hb-Vs deliver more Hb to the vicinity of the endothelial cells. Both Hb-Vs and red blood cells absorb the laser energy and generate heat, supporting the removal of very small blood vessels and deeper subcutaneous blood vessels with PDL irradiation in in vivo experiments. Here, we analyzed the photosensitizing effect of Hb-Vs in PDL irradiation on large blood vessels and surrounding soft tissues. We histopathologically analyzed markers of damage to the large vessels and surrounding dermal tissue in a rabbit auricle model following PDL irradiation alone or subsequent to the addition of intravenous Hb-V injection. Markers were graded on a five-point scale and statistically compared. The changes in laser light absorption and reflection in a human skin model caused by the administration of Hb-Vs were evaluated using Monte Carlo light-scattering programs. Histological markers of damage to blood vessels were significantly greater in Hb-V-injected arteries and veins measuring 1-3 mm in diameter as compared with the controls. However, Hb-V injection significantly reduced PDL-induced necrosis and hemorrhage in the surrounding tissues. During computer simulation, photon absorption increased within the vessel layer and decreased around the layer. Intravenous Hb-Vs increase the extent of damage in larger vessel walls but significantly reduce damage to the surrounding skin after subsequent PDL irradiation. These beneficial effects are the result of improving vessel selectivity by Hb-Vs in vessels. Hb-V administration prior to PDL irradiation therapy could mechanically improve the outcomes and safety profiles of port-wine stain treatment protocols.

Infection-associated decrease of serum creatine kinase levels in Fukuyama congenital muscular dystrophy.

BACKGROUND: Marked decreases in serum creatine kinase levels have been noted in Duchenne and Becker muscular dystrophies as rare complications of autoimmune or autoinflammatory diseases. SUBJECTS AND METHODS: The influence of systemic inflammation on serum creatine kinase levels was reviewed from the charts of three subjects with Fukuyama congenital muscular dystrophy. RESULTS: A total of 30 infectious events were identified. Elevated serum C-reactive protein levels coincided with decreased creatine kinase levels on 19 occasions. In one subject, administration of 2 mg/kg/d prednisolone for bronchial asthma resulted in a decrease in creatine kinase level on six other occasions. CONCLUSION: Apart from an increase in endogenous cortisol secretion, certain inflammation-related molecules could play a role in mitigating muscle cell damage in Fukuyama congenital muscular dystrophy during febrile infectious episodes. Corticosteroids may be a promising agent for the treatment of muscular symptoms in this disorder.

Iron imaging in myocardial infarction reperfusion injury.

Restoration of coronary blood flow after a heart attack can cause reperfusion injury potentially leading to impaired cardiac function, adverse tissue remodeling and heart failure. Iron is an essential biometal that may have a pathologic role in this process. There is a clinical need for a precise noninvasive method to detect iron for risk stratification of patients and therapy evaluation. Here, we report that magnetic susceptibility imaging in a large animal model shows an infarct paramagnetic shift associated with duration of coronary artery occlusion and the presence of iron. Iron validation techniques used include histology, immunohistochemistry, spectrometry and spectroscopy. Further mRNA analysis shows upregulation of ferritin and heme oxygenase. While conventional imaging corroborates the findings of iron deposition, magnetic susceptibility imaging has improved sensitivity to iron and mitigates confounding factors such as edema and fibrosis. Myocardial infarction patients receiving reperfusion therapy show magnetic susceptibility changes associated with hypokinetic myocardial wall motion and microvascular obstruction, demonstrating potential for clinical translation.

Effect of total callosotomy on KCNQ2-related intractable epilepsy.

AIM: To describe beneficial effects of callosotomy on KCNQ2-related intractable epilepsy. CASE REPORT: Our patient was a 10-year-old girl who had developed epilepsy during the neonatal period, accompanied by a suppression-burst pattern on the electroencephalography (EEG). The patient showed profound psychomotor developmental delay since early infancy. Daily seizures of versive posturing and ocular deviation were transiently controlled by carbamazepine and valproate at the age of 1 year; however, the seizures gradually increased to up to 50 times per day. Ictal EEG and positron emission tomography revealed an epileptic focus in the left frontal lobe at age 5 years. Total callosotomy resulted in marked reduction of epileptic seizures thereafter, as well as improved responses to external auditory and visual stimuli. Whole exome sequencing at age 9 identified a de novo missense variant in KCNQ2 (NM_172107.3:c.563A > C:p.(Gln188Pro)). CONCLUSION: This case supports that epilepsy surgery could benefit children with epileptic encephalopathy, even with the etiology of channelopathy.

Infected aortic pseudoaneurysm repair using autologous common femoral artery patch and fascia.

Using autologous common femoral artery and external oblique muscle fascia is a simple and reliable option for repairing infected aortic pseudoaneurysms. Reoperation of infected pseudoaneurysms is challenging and requires secure aortic repair with complete infection eradication. Here, we report two cases of infected pseudoaneurysms in the ascending aorta cannulation site after cardiac surgeries. Common femoral arteries and fascia were harvested in the same lesion as repair materials. The aortic pseudoaneurysms were repaired under deep hypothermic circulatory arrest. Femoral arterial patches were reinforced with circumferential aponeurosis strips. There was no infection recurrence or repair site dilatation in the long-term follow up of both patients.

A Case of Periaortic Lymphoma Mimicking Complicated Type B Acute Aortic Dissection: A Pitfall in the Endovascular Surgery Era.

We report a case of periaortic lymphoma mimicking Stanford type B acute aortic dissection treated for impending rupture by thoracic endovascular aortic repair. Although no endoleak was detected, the aneurysm enlarged continuously. Repeat computed tomography scans showed that an aortic aneurysm-like structure around the stent graft had enlarged irregularly. Histopathological examination revealed diffuse large B-cell malignant lymphoma. Post-chemotherapy, the aneurysm-like structure disappeared without any fistula or rupture. In open surgery, differentiating between aneurysms and malignancy is easy under direct vision; however, in the endovascular surgery era, this is a pitfall because no surgical specimen of the lesion can be obtained.

Optimized mitral annuloplasty ring design reduces loading in the posterior annulus.

OBJECTIVE: The study objective was to develop a novel annuloplasty ring with regional flexibility and assess its suture force dynamics in healthy ovine subjects compared with fully rigid or fully flexible rings. METHODS: Materially heterogeneous rings were created with rigid anterior and posterior, and flexible commissural segments. These rings were created to match the geometry of the Profile 3D ring (Medtronic, Minneapolis, Minn). Each ring was instrumented with 10 force transducers to measure cyclic suture forces (FC) and undersized annuloplasty was performed in 6 healthy ovine subjects. Each FC was recorded and examined for cardiac cycles reaching a maximum left ventricular pressure of 100, 125, and 150 mm Hg. FC was compared with previously reported values from fully rigid Profile 3D and fully flexible prototype rings. RESULTS: Relative to the fully rigid ring, the heterogeneous ring exhibited 48% reduction in FC at its commissural (rigid vs heterogeneous: 1.80 ± 0.94 N vs 0.95 ± 0.52 N; P < .001) and 32% reduction in posterior (1.90 ± 0.92 N vs 1.29 ± 0.91 N; P < .001) regions, but not in its anterior region (2.45 ± 1.21 N vs 2.23 ± 1.22 N; P = .279). Relative to the fully flexible ring, the heterogeneous ring exhibited no significant differences in FC in any region. CONCLUSIONS: The reduced FC of the heterogeneous ring relative to the fully rigid ring suggests a promising approach to reduce suture loading while preserving the annular remodeling capability of fully rigid rings. Future studies in diseased subjects are necessary to explore repair effectiveness of this ring.

Thrombectomy and reconstruction of the left vertebral artery after total arch replacement: never give up on postoperative stroke.

The patient was a 64-year-old man who had aortic regurgitation, ischemic heart disease, a transverse aortic aneurysm, and an abdominal-common iliac aneurysm. Concomitant operations including aortic valve replacement, coronary artery bypass grafting, and total aortic arch replacement with elephant trunk technique were performed successfully. The patient developed postoperative cardiac tamponade on the 5th postoperative day, resulting in bulbar palsy due to occlusion of the dominant left vertebral artery. Thrombectomy of the vertebral artery with reconstruction by a saphenous vein was performed. The patient's neurological symptoms improved after the operation. Revascularization of ischemic stroke may yield neurological improvement even in patients after cardiovascular surgery.

Dietary soybean oil, canola oil and partially-hydrogenated soybean oil affect testicular tissue and steroid hormone levels differently in the miniature pig.

The present study was conducted to examine the influence of dietary canola oil (CAN) and partially-hydrogenated soybean oil (HSO) compared to soybean oil (SOY, control) on the morphology and function of testes using miniature pigs as the test subject. Male miniature pigs were fed a diet containing 10%SOY, 9%CAN+1%SOY, or 9%HSO+1%SOY for 18 months. The scheduled autopsies revealed no abnormalities in histopathological examination of the major organs, except the testes. Atrophy of the seminiferous tubules and hyperplasia in the Leydig cells were found in the SOY and CAN groups. DNA microarray analysis indicated downregulation in the CAN and the HSO groups of genes encoding for gonadotropins in the pituitary gland and of enzymes and proteins involved in steroid hormone metabolism in the testes, compared to the SOY group. Plasma levels of sex hormones in the CAN and HSO groups tended to be higher and testosterone and dihydrotestosteorne in the HSO group were significantly higher than in the SOY group. These results demonstrate that testes are morphologically and functionally affected by the dietary oils, while the plasma steroid hormone levels do not necessarily reflect the gene expression, probably owing to feedback regulation via the gonadal hormones in the hypothalamus-pituitary-gonadal axis.

[Re-operation for Recurrent Constrictive Pericarditis with Multiple Organ Dysfunction].

The patient was a 64-year-old man with recurrent constrictive pericarditis which developed 12 years after the initial pericardiectomy. He had bilateral heart failure with severe left ventricular diastolic dysfunction, massive ascites, renal failure, and coagulopathy. Computed tomography showed a heavily calcified pericardium around the right atrium, the phrenic side of the right ventricle, and the left ventricle. He underwent pericardiectomy via median sternal re-entry. The calcified pericardium was safely decorticated with an ultrasonic surgical knife. The pericardium around the left ventricular side was safely decorticated under cardiopulmonary bypass and use of a heart positioner. Although permanent hemodialysis was necessary after the operation, he has been well for 6 years since the operation.

MACF1 Mutations Encoding Highly Conserved Zinc-Binding Residues of the GAR Domain Cause Defects in Neuronal Migration and Axon Guidance.

To date, mutations in 15 actin- or microtubule-associated genes have been associated with the cortical malformation lissencephaly and variable brainstem hypoplasia. During a multicenter review, we recognized a rare lissencephaly variant with a complex brainstem malformation in three unrelated children. We searched our large brain-malformation databases and found another five children with this malformation (as well as one with a less severe variant), analyzed available whole-exome or -genome sequencing data, and tested ciliogenesis in two affected individuals. The brain malformation comprised posterior predominant lissencephaly and midline crossing defects consisting of absent anterior commissure and a striking W-shaped brainstem malformation caused by small or absent pontine crossing fibers. We discovered heterozygous de novo missense variants or an in-frame deletion involving highly conserved zinc-binding residues within the GAR domain of MACF1 in the first eight subjects. We studied cilium formation and found a higher proportion of mutant cells with short cilia than of control cells with short cilia. A ninth child had similar lissencephaly but only subtle brainstem dysplasia associated with a heterozygous de novo missense variant in the spectrin repeat domain of MACF1. Thus, we report variants of the microtubule-binding GAR domain of MACF1 as the cause of a distinctive and most likely pathognomonic brain malformation. A gain-of-function or dominant-negative mechanism appears likely given that many heterozygous mutations leading to protein truncation are included in the ExAC Browser. However, three de novo variants in MACF1 have been observed in large schizophrenia cohorts.

Effect of inflow cannula side-hole number on drainage flow characteristics: flow dynamic analysis using numerical simulation.

BACKGROUND: Venous drainage in cardiopulmonary bypass is a very important factor for safe cardiac surgery. However, the ideal shape of venous drainage cannula has not been determined. In the present study, we evaluated the effect of side-hole number under fixed total area and venous drainage flow to elucidate the effect of increasing the side-hole numbers. METHOD: Computed simulation of venous drainage was performed. Cannulas were divided into six models: an end-hole model (EH) and models containing four (4SH), six (6SH), eight (8SH), 10 (10SH) or 12 side-holes (12SH). Total orifice area of the side-holes was fixed to 120 mm2 on each side-hole cannula. The end-hole orifice area was 36.3 mm2. The total area of the side-holes was kept constant when the number of side-holes was increased. RESULT: The mean venous drainage flow rate of the EH, 4SH, 6SH, 8SH, 10SH and 12SH was 2.57, 2.52, 2.51, 2.50, 2.49, 2.41 L/min, respectively. The mean flow rate decreased in accordance with the increased number of side-holes. CONCLUSION: We speculate that flow separation at the most proximal site of the side-hole induces stagnation of flow and induces energy loss. This flow separation may hamper the main stream from the end-hole inlet, which is most effective with low shear stress. The EH cannula was associated with the best flow rate and flow profile. However, by increasing side-hole numbers, flow separation occurs on each side-hole, resulting in more energy loss than the EH cannula and flow rate reduction.