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PubMed1992

[On the fenestration of the vertebral and basilar arteries].

The fenestration of the vertebral and basilar arteries was investigated macroscopically in 370 human cases. Altogether 43 fenestrations were found in 32 (8.6%) out of 370 cases. The fenestrations could be divided in three groups according to the position where the fenestration appeared. Group I was the fenestration observed along the vertebral artery (Fig. 1), and 7 such fenestrations were found in 6 (1.6%) out of 370 cases; 3 fenestrations among them were located on the right side, 2 were located on the left side and 1 was found on the bilateral vertebral arteries. In 4 out of 7 fenestrations in this group, the hypoglossal nerve was found passing through the fenestration. Group II was the fenestration observed along the basilar artery (Fig. 2), and 26 fenestrations of this type were found in 20 (5.4%) out of 370 cases: 23 fenestrations (88.5%) were located at the caudal half, 3 (11.5%) were located on the rostral half of the basilar artery (Fig. 5). A close relation was indicated between the side on which the fenestration appeared in the basilar artery and the largeness in caliber of the vertebral artery of either side. Group III was the fenestration observed at the lateral area of the vertebral and basilar arteries (Fig. 3), and 10 fenestrations of this type were found in 9 (2.4%) out of 370 cases; all the fenestrations were located on the right side. In this group, the hypoglossal nerve was observed passing through the fenestratin in 4 out of the 10 fenestrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed2000

Aortic fenestration for acute or chronic aortic dissection: an uncommon but effective procedure.

BACKGROUND: Aortic fenestration is rarely required for patients with acute or chronic aortic dissection. To better define its role and the indications for its use and to evaluate its success at relieving organ or limb malperfusion, we reviewed our experience with direct fenestration of the aorta. METHODS: A retrospective analysis of all consecutive aortic fenestrations performed between January 1, 1979, and December 31, 1999, was performed. Fourteen patients, 12 men and two women (mean age, 59.6 years; range, 43-81), underwent fenestration of the aorta. All patients were hypertensive and had a history of tobacco use. By Stanford classification, there were three type A and 11 type B patients. In the acute dissection group (n = 7), indications for surgery were malperfusion in six patients (leg ischemia, 4; renal ischemia, 5; bowel ischemia, 3) and intra-abdominal bleeding from rupture in two. In the chronic dissection group (n = 7), indications for surgery were abdominal aortic aneurysm in 4 patients (infrarenal, 3; pararenal, 1), thoracoabdominal aneurysm in 1, hypertension from coarctation of the thoracic aorta in 1, and aortic occlusion with disabling claudication in 1. RESULTS: Emergency aortic fenestration was performed in seven patients (surgically for 6 and percutaneously for 1). Fenestration level was infrarenal in four and pararenal in three. Concomitant abdominal aortic graft replacement was performed in four patients, combined with ascending aortic replacement (n = 1) and bilateral aortorenal bypasses (n = 1). In two patients, acute fenestration was performed for organ malperfusion after prior proximal aortic replacement (ascending aorta, 1; descending thoracic aorta, 1). Seven elective aortic fenestrations were performed for chronic dissection (descending thoracic aorta, 2; paravisceral aorta, 2; infrarenal aorta, 2 and pararenal aorta, 1). Concomitant aortic replacement was performed in six patients (abdominal aorta, 5; thoracoabdominal aorta, 1). Fenestration was successful at restoring flow in all 10 patients with malperfusion. Operative mortality for emergency fenestration was 43% (3/7). The three deaths that occurred were of patients with anuria or bowel ischemia, or both. There were no postoperative deaths for elective fenestration. At a mean follow-up of 5.1 years, there were no recurrences of malperfusion and no false aneurysm formations at the fenestration site. CONCLUSION: Fenestration of the aorta can effectively relieve organ or limb ischemia. Bowel ischemia and anuria are indicators of dismal prognosis and emergency fenestration in these patients carries a high mortality. Elective fenestration combined with aortic replacement can be performed safely in chronic dissection. Aortic fenestration is indicated for carefully selected patients with malperfusion and offers durable benefits.

Acute Disease↗

PubMed2001

Effect of fenestration on the sub-diaphragmatic venous hemodynamics in the total-cavopulmonary connection.

OBJECTIVE: To understand differences in the sub-diaphragmatic venous physiology between patients with fenestrated and non-fenestrated total-cavopulmonary connections (TCPC). METHODS: We studied the effects of respiration, retrograde flow, and gravity on the sub-diaphragmatic venous flows in 20 normal healthy volunteers (control), 25 Fontan patients with non-fenestrated TCPC, and 21 with fenestrated TCPC. Subhepatic inferior vena cava (IVC), hepatic vein (HV), and portal vein (PV) flow rates were measured with Doppler ultrasonography during inspiration and expiration in both supine and upright positions. The supine inspiratory-to-expiratory flow rate ratio was calculated to reflect the effect of respiration, the supine-to-upright flow rate ratio was calculated to assess the effect of gravity, and the magnitude of retrograde flow was evaluated with respect to total antegrade flow. Mean IVC, HV, and wedged hepatic venous (WHV) pressures were measured during cardiac catheterization in four TCPC patients before and after fenestration closure. The transhepatic venous pressure gradient (TVPG) was calculated as the difference between the HV and WHV pressure. RESULTS: Compared with control, HV flow in TCPC was heavily dependent on respiration; this inspiratory capacity was greater in fenestrated than non-fenestrated subjects (inspiratory-to-expiratory flow ratio 1.7, 4.4, and 3.0, respectively P<0.001). Normal retrograde HV flow was diminished in TCPC patients, furthermore, fenestrated subjects had less flow reversal than non-fenestrated (retrograde as percent of antegrade flow 43, 19, and 30%, respectively P<0.001). Gravity decreased IVC and HV flows more in TCPC subjects than control, but this effect was not different between the two TCPC groups. Closure of the fenestration resulted in higher IVC and HV pressures (pre-closure versus post-closure pressures [mmHg]: 11.2 +/- 4.0 vs. 12.3 +/- 3.9, and 11.5 +/- 3.8 vs. 12.4 +/- 3.8, respectively P< or =0.001). The normal TVPG was reduced in fenestrated TCPC, and worsened after fenestration closure (0.9 +/- 0.3 and 0.7 +/- 0.4, respectively P < 0.04). CONCLUSIONS: Fenestration of the inferior venous connection has important influences on sub-diaphragmatic venous return in TCPC patients. Although fenestration lowers venous pressures and partially restores TVPG, its beneficial effects on flow in TCPC patients are mediated primarily by an increase in inspiration-derived forward HV flow and reduced flow reversal. These observations suggest fenestration results in a more efficient and less congested splanchnic circulation in TCPC patients, and may have important implications in the early and late management of Fontan patients.

Blood Flow Velocity↗

PubMedDate not supplied

Fenestrations in the internal elastic lamina at bifurcations of human cerebral arteries.

Measurements of fenestrations (or windows) in the internal elastic lamina at the bifurcation of human cerebral arteries, were obtained from photomicrographs (scanning electron microscope). Thirteen of 28 bifurcations revealed regions of enlarged fenestrations among the normal fenestrations in the vicinity of the apex. The mean diameter of the enlarged fenestrations (7.0 +/- 0.34 SEM micrometer) was significantly greater than the mean diameter (2.1 +/- 0.13 SEM micrometer) of the normal fenestrations. The number of fenestrations per sq mm was less (2606 +/- 284 SEM per sq mm) for the enlarged fenestrations than for the normal fenestrations (4518 +/- 397 SEM per sq mm). The proportion of the area of internal elastic lamina comprised of fenestrations increased to 15.0 +/- 1.1 SEM percent for the enlarged fenestrations from a mean of 1.8 +/- 0.16 SEM percent for the normal fenestrations. Fenestrations from bifurcations without enlarged fenestrations, demonstrated characteristics similar to the normal fenestrations. More than 80% of the specimens exhibited a gap in the internal elastic lamina in the apical region of the bifurcation. Based on a comparison of stress concentration factors, we propose that the presence of enlarged fenestrations represents a weakness in the internal elastic lamina at the bifurcation apex which may contribute to the initiation of microaneurysms.

Aged↗

PubMed1999

Is it necessary to routinely fenestrate an extracardiac fontan?

OBJECTIVES: This study was conducted to assess the need for, and use of, fenestration of an extracardiac conduit Fontan. BACKGROUND: Fenestration of a Fontan connection has been proposed as a means of improving outcomes of single ventricle palliation. The benefit of fenestration is likely to be greatest in the early postoperative period when patients may experience increased pulmonary vascular resistance and decreased ventricular function due to the effects of cardiopulmonary bypass, aortic cross-clamping and positive pressure ventilation. However, there are potential drawbacks to fenestration. The utility of fenestration with extracardiac Fontan operation has not been determined. METHODS: Since 1992, 81 patients have undergone a modification of the Fontan procedure in which an extracardiac inferior cavopulmonary conduit is used in combination with a previously staged bidirectional Glenn anastomosis. We conducted a retrospective review of these patients. RESULTS: Fenestration was performed selectively in 32 patients (39%), including only 2 of the last 38 (5%). In seven patients, a fenestration was placed or clipped in the early postoperative period without cardiopulmonary bypass. There were two operative deaths. Prolonged (>2 weeks) pleural drainage occurred in 13 patients, 8 with fenestration and 5 without. In addition to undergoing earlier Fontan in our experience, patients who had a fenestration placed had significantly higher preoperative pulmonary vascular resistance, significantly higher common atrial pressure after Fontan and significantly lower post-Fontan systemic arterial oxygen saturation. Fontan pressure did not differ between nonfenestrated and fenestrated patients. At follow-up ranging to five years, there were two late deaths and no patients developed protein losing enteropathy. CONCLUSIONS: Fenestration is not necessary in most Fontan patients when an extracardiac conduit technique is performed as described in this article, and therefore, should not be performed routinely with the extracardiac conduit Fontan. The need for fenestration should be assessed after cardiopulmonary bypass when hemodynamics can be evaluated accurately. Fenestration can be placed and revised easily without bypass and with minimal intervention in patients with an extracardiac conduit Fontan.

Blood Vessel Prosthesis Implantation↗

PubMed1999

Stability of the whole lumbar spine after multilevel fenestration and discectomy.

STUDY DESIGN: An investigation of the in vitro biomechanical effects of multilevel fenestrations and discectomies on the behavior of whole lumbar spine motion, using a material testing system (Instron 1341, Instron Limited, High Wycombe, England) and Elite three-dimensional motion analysis system (BTS, Milano, Italy). OBJECTIVES: To investigate the effects of multilevel fenestrations and discectomies on the stability of the whole lumbar spine, including segmental stiffness and sagittal (horizontal and vertical) translation. SUMMARY OF BACKGROUND DATA: In the management of lumbar spinal stenosis, wide decompressive laminectomy with partial or total facetectomy has been the standard procedure for multilevel nerve decompression. Main complications with these procedures have been instability and chronic pain syndrome. Multilevel fenestration with undermining enlargement of the spinal canal has been selected for multilevel nerve decompression in recent years. However, the biomechanical effects of multilevel fenestration and discectomy have been controversial and difficult to validate. This study investigated the in vitro biomechanical effects of multilevel fenestrations and discectomies on motion behavior of the whole lumbar spine. METHODS: Seven fresh human specimens from L1 to sacrum were used in this study. The fenestrations and discectomies consisted of L3-L4 bilateral fenestration, L4-L5 bilateral fenestration, L5-S1 bilateral fenestration, L4-L5 discectomy, and L5-S1 discectomy. Flexion, lateral bending, and axial rotation (torsion) loading were applied. Ranges of motion were determined two-dimensionally by the Elite system with an infrared camera. The postoperation results were compared with the intact conditions. RESULTS: After multiple fenestrations, the sagittal ranges of motion at L4-L5 increased by 18% anteroposteriorly and 16% vertically under the flexion loads. At L5-S1, the motions increased by 19% and 45%, respectively. After fenestrations and discectomies, the ranges of motion in the sagittal plane increased by 28% horizontally and 71% vertically at L4-L5, and 14% and 166% at L5-S1. Motion increases were statistically significant (P < 0.05) in vertical translations. However, after the multilevel surgeries, no significant motions were found in each of the lumbar segments during lateral bending and axial rotation. CONCLUSIONS: The results demonstrate that multilevel fenestrations and discectomies affect lumbar spinal stability in flexion, but have no effect on the stability of the lumbar spine in lateral bending or axial rotation.

Adult↗

PubMedDate not supplied

Fenestration of intracranial arteries with special attention to associated aneurysms and other anomalies.

PURPOSE: To determine the association of intracranial arterial fenestration and aneurysms. METHODS: We retrospectively reviewed 5,190 cerebral angiogram reports and identified 37 patients with arterial fenestrations. RESULTS: These 37 patients had 38 fenestrated arteries: 16 basilar, 10 vertebral, nine middle cerebral, and three anterior cerebral arteries. Seven of these patients had a total of 13 aneurysms, although only one aneurysm was at the site of a fenestration. The remaining aneurysm patients had fenestrations as unassociated findings. Other anomalies detected were two azygous anterior cerebral arteries, on dural arteriovenous shunt of the cavernous sinus, one extracranial arteriovenous fistula, and one developmental venous anomaly (venous angioma). None of the fenestrations were in the vessels directly involved with these associated lesions. The incidence of aneurysm at the fenestration was 7% (one in 16) for basilar artery fenestrations. Considering all fenestrations, the incidence of aneurysm at the site of fenestration was 3%. CONCLUSION: Our data show that the association of a fenestration with an aneurysm at the fenestration site is not different from the typical association of circle of Willis bifurcations with saccular aneurysms.

Adolescent↗

PubMedDate not supplied

Fenestrated fontan procedure: evolution of technique and occurrence of paradoxical embolism.

The Fenestrated Fontan procedure (FFP) has improved outcome in high risk patients. The technique is evolving, however, and complications are not fully known. Over a 3-year period 13 patients (mean age 35 +/- 29 months) underwent an FFP in our institution. In the first two patients the fenestration had to be created because of high right atrial pressure and low cardiac output; in 11 patients the FFP was planned. In three patients the sutures for the adjustable fenestration were crossing the defect. In 10 patients, purse-string sutures were placed around but not across the defect. Because large fenestrations were created in 11 patients (8-12 mm) Glenn shunts were performed to improve arterial saturation. The postoperative course was relatively uneventful, with chest tubes being removed 1-8 days (mean 4 +/- 3 days) postoperatively and the hospital stay ranging from 7 to 27 days (mean 14 +/- 6 days). One patient had bleeding and another had a mediastinal abscess. The first patient died (7.6%) because of hemodynamic instability due to prolonged cardiopulmonary bypass from the creation and enlargement of the fenestration. One patient had a paradoxical cerebral embolism from clots that formed on the sutures crossing the fenestration. Because of this problem the remaining patients were placed on salicylates while awaiting closure of their fenestration. All 12 patients had their fenestrations closed, performed under local anesthesia in 9, at mediastinal abscess drainage in 1, and spontaneously in 2. We conclude that creation of large fenestrations in combination with Glenn shunts and the use of adjustable fenestrations are viable modifications of the FFP. The use of purse-string sutures around the fenestration and antiplatelet drugs can probably minimize the occurrence of paradoxical embolism.

Child↗

PubMed2000

Univentricular repair: is routine fenestration justified?

BACKGROUND: A decade after the introduction of baffle fenestration, the outcome of Fontan-type repair for hearts with a functional single ventricle finally looks promising. Our study was designed to assess the impact of fenestration on the outcome of univentricular repairs. METHODS: From January 1988 to December 1997, 348 patients (104 with tricuspid atresia and 244 with other morphological diagnoses) underwent univentricular repair at our institute. Since 1994, routine fenestration of the atrial baffle was performed in all patients (n = 126). RESULTS: The overall Fontan failure rate was 14% (50 of 348) and included 45 early deaths and five Fontan take downs. Absence of fenestration was the only and highly significant predictor of Fontan failure (risk ratio [RR] 3.3, 95% confidence interval [CI] 1.49 to 7.31, p = 0.002). Significant pleural effusion was seen in 27% of patients. Absence of fenestration of the atrial baffle (RR 3.97, 95% CI 2.17 to 7.26, p < 0.001) and aortic cross-clamp time more than 60 minutes (RR 2.15, 95% CI 1.3 to 3.5, p = 0.002) were found to be significant risk factors. The follow-up ranged from 6 to 120 months (mean 46.0 +/- 18.0 months). There were 12 late deaths and 5 patients were lost to follow-up. Actuarial survival (Kaplan Meier) at 90 months was 81% +/- 4%. Two hundred and fifty-eight patients (90%) were in New York Heart Association class I at their last follow-up visit. Oxygen saturation in the fenestrated group ranged from 85% to 94% (mean 89%). Thirty patients (26%) had spontaneous closure of the fenestration over a mean period of 34 months, and there has been no incidence of late systemic thromboembolism. In no instance has there been a need to close the fenestration. CONCLUSIONS: Elective fenestration of the intraatrial baffle is associated with decreased Fontan failure rate and decreased occurrence of significant postoperative pleural effusions. Routine elective fenestration of the atrial baffle may, therefore, be justified in all univentricular repairs.

Actuarial Analysis↗

PubMed2000

Parameters associated with perioperative baffle fenestration closure in the Fontan operation.

OBJECTIVE: To identify clinical parameters indicating perioperative fenestration closure in children who underwent the fenestrated Fontan operation. DESIGN: Retrospective. SETTING: Single children's hospital. PARTICIPANTS: Patients who underwent a fenestrated Fontan operation in 1996 through 1997 (n = 101). INTERVENTION: A fenestrated Fontan operation was performed in children with single-ventricle physiology. MEASUREMENTS AND MAIN RESULTS: Early perioperative closure of the fenestration occurred in 14 patients (group 1), whereas the fenestration remained patent in 87 patients (group 2). The groups were compared by the following parameters: demographics, cardiac catheterization and ultrasound data, and use of aspirin or warfarin preoperatively and intraoperatively by assessing the composition of the cardiopulmonary bypass solution, use of ultrafiltration and antifibrinolytics, protamine dose, last hematocrit on cardiopulmonary bypass, and requirement of blood products. Immediately postoperatively in the intensive care unit (ICU), cardiac filling pressures (central venous and left atrial pressure), coagulation profile, cardiac rhythm, chest tube drainage, length of stay in the ICU, and use of atrial pacing were reviewed. Significant indicators of early fenestration closure in this study as determined by multivariate stepwise logistic regression were a high transpulmonary pressure gradient (p = 0.015) and a higher oxygen saturation (p = 0.001) 1 hour after arrival in the ICU, a low fibrinogen level (p < 0.0001), and the need for temporary atrial pacing (p = 0.029). The fenestration was reopened in 13 patients in group 1. In 101 patients, there was no early mortality, and all patients survived to discharge. CONCLUSION: Factors that correlated with postoperative fenestration closure in the fenestrated Fontan operation in this study were a high transpulmonary pressure gradient and a high oxygen saturation 1 hour after arrival in the ICU, a low fibrinogen level, and the need for temporary atrial pacing.

Child↗

PubMed2005

Fenestrations in the jaws of laparoscopic graspers.

Laparoscopic graspers used for manipulating delicate tissue generally possess jaws with fenestrations (windows). The fenestrations should enhance the grip on the tissue; however, fenestrations reduce the contact area between jaws and tissue, leading to higher local pressures and possibly tissue damage. Experiments were performed to determine the effect of a fenestration on the pinch force needed to prevent slip of tissue and on the pinch force leading to tissue damage. In addition, the size and position of the fenestration were determined. Fenestrated jaws resulted in increased tissue damage, without affecting the pinch force needed to prevent slip. These negative effects increased with increasing fenestration size and when the fenestration was located toward the tip of the jaws. Therefore, fenestrated jaws had a smaller safe working range than the jaws without fenestrations.

Journal Article↗

PubMed1992

Effect of baffle fenestration on outcome of the modified Fontan operation.

BACKGROUND: The "fenestrated Fontan" (surgical baffle fenestration followed by transcatheter test occlusion and permanent closure after postoperative recovery) was adopted in an effort to reduce perioperative mortality and morbidity. This study assesses the effect of baffle fenestration on outcome. METHODS AND RESULTS: Patients having a modified Fontan operation with a cavocaval baffle and cavopulmonary anastomosis were retrospectively selected for study. Those with baffle fenestration (n = 91) were compared with those without baffle fenestration (n = 56) with respect to preoperative risk factors, age, anatomy, surgical date, and presence or absence of a previous bidirectional cavopulmonary anastomosis. Outcome variables were failure (death or take-down) and duration of postoperative pleural effusions and hospitalization. Survival and clinical status after hospital discharge were ascertained. The two groups did not appear to differ with respect to age or anatomic diagnosis. Patients having baffle fenestration were at significantly greater preoperative risk by univariate and multivariate analysis (p < 0.01). Operative failure was low in both groups (11% without and 7% with baffle fenestration, p = NS). Durations of pleural effusions and hospitalization were significantly shorter with baffle fenestration (p < 0.01). Neither date of surgery nor a previous bidirectional cavopulmonary anastomosis appeared to contribute to improved outcome. Patients with baffle fenestration had lower postoperative systemic venous pressure (p < 0.01). There were no late deaths. Functional status in both groups is good (82% in New York Heart Association class I). CONCLUSIONS: Baffle fenestration is associated with low mortality, significantly less pleural effusion, and significantly shorter hospitalization among high-risk patients having a modified Fontan operation.

Cardiac Surgical Procedures↗

PubMed2006

Effect of width of disk fenestration and a ventral slot on biomechanics of the canine C5-C6 vertebral motion unit.

OBJECTIVE: To investigate the effects of disk fenestration and ventral slot formation on vertebral motion unit (VMU) range of motion (ROM) and determine the effects of fenestration and ventral slot width on VMU ROM. SAMPLE POPULATION: C5-C6 VMUs from 10 skeletally mature canine cadavers. PROCEDURES: Specimens were assigned to 2 groups (5 specimens/group). Surgery was performed in which width of a fenestration and a ventral slot was 33% (group 1) or 50% (group 2) the width of the vertebral body. Flexion-extension, lateral bending, and axial torsion ROMs were measured during loading before surgery, after fenestration, and after ventral slot formation. Range of motion was compared within groups to determine effects of surgical procedure on stability and between groups to determine effects of width of fenestration and ventral slot on stability. RESULTS: For both groups, fenestration resulted in a significant increase in ROM during flexion-extension, compared with results for intact specimens. Ventral slot formation resulted in a significant increase in ROM during flexion-extension and lateral bending, compared with results for intact specimens. Ventral slot formation resulted in a significant increase in ROM only during flexion-extension, compared with results for fenestrated specimens. There were no significant differences in ROM of the intact, fenestrated, and ventral slot specimens between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results suggests that fenestration and ventral slot procedures each affect the biomechanics of the C5-C6 VMU. Width of a fenestration or ventral slot up to 50% of the width of C5-C6 may be clinically acceptable.

Analysis of Variance↗

PubMed2006

Transcatheter closure of fenestration with detachable coils after the Fontan operation.

We report our experience in 13 patients who underwent transcatheter closure of Fontan fenestration with the Cook detachable coils. These patients underwent the extracardiac type Fontan operation with a short conduit fenestration (n=7) or lateral tunnel type with a punch-hole fenestration (n=6). Fenestration closure was done at the mean age of 5.1+/-2.4 yr, average of 32 months after the Fontan operation. We used one to three coils depending on the fenestration type, size, and residual shunt. Aortic oxygen saturations increased by an average of 5.4 (2-9)% and mean pressures in the Fontan circuit increased by an average of 2.1 (0-6) mmHg. During follow-up (median of 23 months), five patients (4 in extracardiac, 1 in lateral tunnel) had complete occlusion of the fenestration on echocardiography. There was no immediate or late complication. Transcatheter closure of fenestration in Fontan operation using the Cook detachable coil is a safe and feasible technique. However, the coil was ineffective for closure of a punch-hole fenestration in the lateral tunnel type operation. In the conduit type fenestration, some modification of fenestration method instead of a short conduit for coil closure or use of new device is necessary to increase complete closure rate.

Cardiac Catheterization↗

PubMed2005

[Closure of extrocardiac Fontan fenestration by using the Amplatzer duct occluder].

INTRODUCTION: A direct or tubular communication between the systemic venous system and the systemic atrium, generally called fenestration, is surgically created to improve the postoperative period of patients undergoing total cavopulmonary connection. However, a fenestration prompts a potentially deleterious right to left shunt, and is generally closed after the postoperative period. Direct fenestrations can be closed using coils, or devices designed for atrial septal defect closure. However, no devices have been designed for closure of extracardiac fenestrations. We report our experience concerning the closure of extracardiac Fontan fenestration by the Amplatzer duct occluder (ADO). METHODS: From January 2001 to December 2002, we closed extracardiac Fontan fenestrations using the ADO device in 10 consecutive patients. Indications to fenestration closure were: low velocity shunt through the fenestration, mild desaturation, and absence of effusions. RESULTS: All patients had a successful closure of the fenestration. The procedure was performed through the femoral vein in 7 cases and through the right jugular vein in 3. Mean central venous pressure increased not significantly from 12 to 13-mmHg. Mean oxygen saturation increased significantly from 90 to 97% (p<0.001). Immediate shut abolition was obtained in 9 cases. No complications were observed. At a median follow-up of 12 months (range 6-18 months), all patients are free of symptoms and have a normal oxygen saturation at rest as well as at exertion. CONCLUSION: The ADO device allowed closing the extracardiac Fontan fenestration in all patients with no mortality, no morbidity and a rate of 100% of complete closure at mid-term follow-up.

Adolescent↗

PubMed1997

Neovasculature induced by vascular endothelial growth factor is fenestrated.

We have reported previously that topical administration of vascular endothelial growth factor165 (VEGF) to a microvascular bed supplied with a continuous endothelium can rapidly induce the formation of endothelial fenestrations (W. G. Roberts and G. E. Palade, J. Cell Sci., 108: 2369-2379, 1995). From these results, we hypothesized that tumor vasculature, in general, may also be fenestrated because it has been reported that tumor secretion of VEGF causes the surrounding host vasculature to invade and feed the growing tumor. Using electron microscopy to characterize the endothelial cell morphology in tumor vessels from either the periphery or the core of the tumor and immunoblotting to detect secreted VEGF, we analyzed the vasculature of human and murine neoplastic tumors grown s.c. in male nude mice. To clarify the role of VEGF165 two models were used: (a) Chinese hamster ovary (CHO) cells stably transfected with hu VEGF165 and injected into mice (VEGF:CHO tumors); and (b) slow-release pellets containing purified VEGF or basic fibroblast growth factor implanted on the rat cremaster muscle. All tumors had vessels with fenestrated endothelium, open interendothelial junctions, and clustered fused caveolae. From all of the peripheral tumor vessels observed, fenestrated endothelium was observed in 41% from EMT, 35% from M1S, 37% from U87, and 56% from VEGF:CHO tumors, whereas surrounding skin and muscle, from which tumor vessels were derived, had fenestrated endothelium in 2 and 0% of all vessels, respectively. Additionally, further analysis revealed a substantial decrease in the anionic glycocalyx on the luminal face of the fenestral diaphragms in endothelium from tumors (especially VEGF:CHO) when compared to intestine or pancreas. Because the host tissue microvascular endothelium which supplies the tumor is not fenestrated, tumors can transform nonproliferating, nonfenestrated vessels into proliferating vessels, many of which have fenestrated endothelium. These data provide evidence that chronic VEGF exposure can induce fenestrations in nonfenestrated endothelium similar to the fenestrated endothelium found in tumor vessels.

Animals↗

PubMed2004

Semicircular canal fenestration - improvement of bone- but not air-conducted auditory thresholds.

Auditory stimulation can, under certain circumstances, activate the vestibular end organs and this is facilitated by fenestration of a semicircular canal (SCC). Several fenestrated profoundly deaf patients reported improvements in their bone- (BC) but not air-conducted (AC) thresholds. Bone conduction auditory thresholds have been reported to be better than normal in several patients with thinning or absence of bone over a SCC (dehiscence). This phenomenon was carefully studied in the fat sand rat (Psammomys obesus) by recording auditory brainstem evoked responses to BC and AC auditory stimulation, before and after SCC fenestration. Fenestration would be expected to decrease the pressure difference across the cochlear partition, causing a reduction in the amplitude of the classical base to apex input traveling wave, and should therefore lead to an elevation in AC and BC thresholds. Instead, BC thresholds decreased (i.e. improved) following fenestration (by 7.0+/-4.2 dB; P<0.005), while AC thresholds did not change. Thus the cochlea becomes more sensitive to BC, but not AC, stimulation in the presence of a SCC fenestration. This may be due to the removal by the fenestration of a factor impeding BC cochlear responses, or by the addition of a facilitating factor. The result that the SCC fenestration did not affect AC threshold provides support for the concept that at low intensities the outer hair cells are directly activated by components of the fluid pressures surrounding them, which alternate at audio-frequencies. These cochlear fluid audio-frequency pressures are induced by stapes footplate movement and not by a base to apex input traveling wave. The audio-frequency pressures would not be affected by SCC fenestration. The outer hair cell motility thus induced somehow excites the inner hair cells and the auditory nerve fibers. At low intensities the outer hair cell motility causes localized displacement at the appropriate position on the basilar membrane.

Acoustic Stimulation↗

PubMed1994

Dilation of intra-atrial baffle fenestrations: results in vivo and in vitro.

Spontaneous closure of intra-atrial baffle fenestrations occurred early postoperatively following a Fontan procedure in three patients (ages 0.8-2 yr) and were reopened using transvenous balloon dilation. Following this clinical experience with this complication we studied the effects of high pressure balloons of different sizes on fenestrations created in polytetrafluoroethylene (PTFE) patches. The intra-atrial baffle fenestration was found closed within hours after surgery in two patients and 32 days postoperatively in the other. Increasing edema, chest tube drainage, and renal dysfunction ensued rapidly. At catheterization the balloon dilation in two patients reduced the elevated right atrial pressure, edema, and pleural effusion and allowed an acceptable arterial saturation. In the other patient, with acidosis and a low cardiac output, transient cardiac arrest occurred following passage of the catheter through the fenestration and during later unsuccessful operation the fenestration, although open, was traversed by strands of clot. In the experimental study, a total of 45 fenestrations 4 mm in diameter were dilated with 5, 6, 7, 8, and 9 mm balloons. The fenestration areas remained increased significantly during the 14 days of observation in room air, with the larger balloons producing larger holes. Balloon dilation may be effective for spontaneous fenestration closure occurring in the early postoperative period after a fenestrated Fontan procedure. Our experimental data may be useful in selecting the balloon size in this setting.

Cardiac Surgical Procedures↗