Late fenestration closure in the hypoplastic left heart syndrome: comparison of hemodynamic changes

Use of institutional criteria for transcatheter device closure of Fontan fenestration - Midterm outcomes

Background:

There are no established criteria to decide suitability for Fontan fenestration closure. Our institution has the following criteria: an unobstructed Fontan pathway with no significant decompressing venovenous collaterals, baseline Fontan pressure ≤15 mmHg, baseline cardiac index ≥2 L/min/m², and a decrease in cardiac index ≤20% with test occlusion of the fenestration.

Objective:

The objective of the study was to review midterm outcomes following device closure of Fontan fenestration using institutional criteria.

Materials and Methods:

A retrospective review was performed of patients who underwent catheterization with prior fenestrated Fontan procedure between May 2005 and January 2015. Patients were classified as those who underwent successful closure (A), had closure deferred due to failure to meet criteria (B), or were not referred for closure (C).

Results:

There were 42 patients in Group A, 10 in Group B, and 150 in Group C. The mean Fontan pressure increased from 13.1 ± 2.1 to 14.5 ± 2.1mmHg in Group A and 14.6 ± 1.5 to 15.7 ± 2.2 mmHg in Group B (P = not significant). With test occlusion, cardiac index fell by 18.12% ± 15.68% in Group A and 33.75% ± 14.98% in Group B (P = 0.019). At a median of 46 month follow-up, oxygen saturation increased significantly from 85.15% ± 6.29% at baseline to 94.6% ± 4.43% (P < 0.001) in Group A but with no statistically significant difference in the rates of plastic bronchitis, protein-losing enteropathy, stroke, or heart transplantation between the three groups.

Conclusions:

Using institutional criteria, transcatheter device closure of Fontan fenestration was followed by significant increase in oxygen saturations and no statistically significant difference in morbidity or mortality between closure and nonclosure groups.

Anesthetic Implications of the Fontan Procedure for Single Ventricle Physiology

The Fontan procedure is the operation of choice for patients considered to be candidates for definitive palliation of single ventricle physiology. Anesthetic technique for the Fontan procedure is not well described in the literature, and the medical and surgical treatment of these patients is rapidly evolving. With an understanding of the anatomy and phys iology of the Fontan patient, a safe and effective anesthetic can be executed. An understanding of the changes that occur during the perioperative period is critical. This article focuses on a review of single ventricle physiology and Fon tan physiology, preoperative assessment and risk factors for the Fontan procedure, intraoperative management, and management of low cardiac output in the postbypass period.

Determinants and clinical significance of flow via the fenestration in the Fontan pathway: a multimodality study

BACKGROUND

The use of a fenestration in the Fontan pathway remains controversial, partly because its hemodynamic effects and clinical consequences are insufficiently understood. The objective of this study was to quantify the magnitude of fenestration flow and to characterize its hemodynamic consequences after an intermediate interval after surgery.

METHODS

Twenty three patients with a fenestrated extracardiac conduit prospectively underwent investigation by cardiac magnetic resonance (CMR), echocardiography, and invasive manometry under the same general anesthetic 12 ± 4 months after Fontan surgery. Fenestration flow was determined using phase contrast CMR by subtracting flow in the Fontan pathway above the fenestration from Fontan flow below the fenestration.

RESULTS

Fenestration flow constituted a mean of 31 ± 12% (range 8-50%) of ventricular preload. It was associated with a lower Qp/Qs (r = -0.64, p=0.001) and oxygen saturation (r = -0.74, p<0.0001). Fenestration flow volume was correlated with pulmonary vascular resistance (r = 0.45, p = 0.04) and markers of ventricular diastolic function (early diastolic strain rate r = 0.57, p = 0.008 and ventricular untwist rate r = 0.54, p = 0.02). In 14 patients (61%) all of the net inferior vena cava flow and part of the superior vena cava flow were diverted into the systemic atrium and did not reach the lungs.

CONCLUSIONS

Fenestration flow can be measured accurately with CMR. In two-thirds of the patients not only all of the inferior vena cava flow, but also some of the superior vena cava flow is diverted through the fenestration. Fenestration flow is driven by a balance between pulmonary vascular resistance and early diastolic ventricular function.

Fontan fenestration closure and event-free survival

OBJECTIVES

The purpose of the present study was to evaluate the association of open and closed Fontan fenestration status with event-free survival.

METHODS

All patients who underwent a fenestrated Fontan procedure at our institution from January 1994 through June 2007 were reviewed. Patient information was obtained from the medical records. The patients were assigned to 1 of 2 study groups, open or closed, according to their most recent fenestration status. Clinically relevant morbid events were tabulated, and Kaplan-Meier event analysis was used to create event-free probability curves with log-rank comparisons.

RESULTS

A total of 161 patients were classified as open and 51 as closed. The median interval to an event was 1.1 years (interquartile range, 0.1-3.3 years) after the Fontan procedure. The median interval to closure was 1.2 years (interquartile range, 0.7-3.3 years). The median interval to an event was 1.5 years (interquartile range, 0.1-4.6 years) in the closed group and 1.1 years (interquartile range, 0.1-3.3 years) in the open group. Event-free probability analysis revealed no significant difference between the 2 groups (P = .15). The median follow-up arterial oxygen saturation was greater in the closed group (96.0%; interquartile range, 94.0%-97.0%) than in the open group (91.0%; interquartile range, 86.0%-95.0%; P < .0001).

CONCLUSIONS

Fenestration closure was associated with greater arterial oxygen saturation but not greater event-free survival. The interval to an event was slightly less than the interval to fenestration closure, suggesting potential merit in the evaluation of earlier fenestration closure. Adoption of specific fenestration management guidelines might help improve the overall outcomes and enhance the quality of future studies.

Late catheter interventions in hypoplastic left heart syndrome

Interventional cardiology plays a key role in the diagnosis and management of patients with functionally univentricular physiology after the various stages of surgical palliation. The interventions performed are widely variable in type, including angioplasty of stenotic vessels and implantation of stents in stenotic vessels; closure of defects such as collaterals, leaks in baffles, and fenestrations; creation of fenestration; and more. In the setting of venous hypertension associated with stenosis at the Fontan baffle, conduit, or pulmonary arteries, stent implantation is often preferred, as the aim is to eliminate completely the narrowing, given that relatively mild stenosis can have a significant detrimental hemodynamic effect in patients with functionally univentricular circulation. The procedure is highly successful. In patients who fail after Fontan procedure, creation of a fenestration is often performed, with variable technique depending on the underlying anatomic substrate. To increase chances of patency of the fenestration, implantation of a stent is often required, particularly in the setting of an extracardiac conduit. For those patients with cyanosis and favorable Fontan hemodynamics, closure of the fenestration is performed using atrial septal occluder devices with high success rate. Coils compatible with magnetic resonance imaging are used widely to treat collateral vessels, although on occasion other specific embolization tools are required, such as particles or vascular plugs. Postoperative arch obstruction is successfully managed with angioplasty at a younger age, while implantation of a stent in the aorta is reserved for older patients. Specifics of these interventional procedures as applied to the population of patients with functionally univentricular hearts are described in this manuscript.

Obstruction of lateral tunnel fontan by an adjustable occluder device

Innovative ways of adjusting Fontan fenestrations have been developed over the last two decades. Long-term complications have not been described. We successfully treated one such complication of Fontan conduit obstruction due to an adjustable occluder device.

Percutaneous management of a Fontan fenestration: in search for the ideal restriction-occlusion device

OBJECTIVE

Most devices devices available for percutaneous closure of Fontan fenestrations tend to be bulky. The aim of this study was to evaluate a low profile custom made device and assess its efficacy and safety.

PATIENTS AND METHODS

A 15 mm PFO star was used as the basis. The following modifications were made: removal of the left disc to reduce thrombogenicity in the left atrium, increase the length of the LA legs from 2 by 15 mm to 3 by 20 mm to prevent dislodgement and later adding a pivot between the left and right umbrella. A partial occluder was made by removing two opposite quadrants from the proximal disk.

RESULTS

Device deployment was possible in 93% (63 of 68) patients. In five patients, the device could not be deployed and an alternative device was used. In 45 patients complete closure of the fenestration was obtained and saturations increased from 84% +/- 4% to 95% +/- 2% (P < 001). In 18 high risk patients with suboptimal Fontan circulation, a modified device was used to effect partial occlusion: saturations increased from 79% +/- 7% to 90% +/- 4% (P < 0.001); a residual shunt persisted in most patients for several months. No thrombotic events were recorded during follow-up.

CONCLUSIONS

The modified PFO star device can safely be deployed in Fontan patients to occlude or restrict flow through a fenestration. It has a low profile with minimal foreign material, is non-obstructive and minimally thrombogenic.

Use of a fenestration should be routine during the Fontan procedure: PRO

The physiologic effects of a fenestration are to decrease "Fontan pressure" and systemic oxygen saturation, but to improve both cardiac index and systemic oxygen delivery. Several nonrandomized studies have shown that a fenestration improves clinical outcomes by decreasing the duration of postoperative effusions and the length of hospital stay. The single prospective, randomized study has also shown that use of a fenestration improves clinical outcomes. While there are some disadvantages to a fenestration; these are of relatively limited clinical importance. Selective rather than routine use of a fenestration relies on the ability to predict outcome based on preoperative or intraoperative variables. However, none of these variables has been found to have useful predictive value in the individual patient. In conclusion, the Fontan procedure can be done without a fenestration, with good outcomes. However, the positive effects of a fenestration on duration of effusions and length of hospital stay argue that use of a fenestration should be routine during the Fontan procedure.

Current treatment and prognosis in children with functionally univentricular hearts

For more than 30 years Fontan-type procedures have been performed for surgical treatment in patients with functionally univentricular hearts. Advances in proper patient selection, staging of the Fontan palliation, and modifications of the surgical technique resulted in continuous improvement of the surgical results during the past two decades. However, increasing experience with medium term and long term follow-up of the Fontan circulation has drawn attention to a number of sequelae and chronic complications affecting a significant number of patients.

Fenestration improves clinical outcome of the fontan procedure: a prospective, randomized study

BACKGROUND

The Fontan procedure is the definitive operation for palliation of complex congenital heart disease with single-ventricle physiology. Fenestration of the Fontan circuit allows for shunting of deoxygenated blood to the systemic circulation. This procedure improved the clinical outcomes of patients who are at high risk for poor Fontan results. However, it is controversial whether fenestration is beneficial for standard-risk patients.

METHODS AND RESULTS

This prospective, randomized trial evaluated the clinical utility of fenestration in patients with standard preoperative risk profiles for Fontan surgery. Forty-nine consecutive patients were assigned to undergo either a fenestrated (25 patients) or nonfenestrated (24 patients) Fontan procedure. The fenestrated and nonfenestrated groups were comparable with respect to age (P=0.944), body surface area (P=0.250), number of preoperative risk factors for poor outcome (P=0.681), cardiopulmonary bypass time (P=0.302), number of patients who required aortic cross-clamping (P=0.240), preoperative oxygen saturation (P=0.101), and number of patients with dominant left ventricular morphology (P=0.534). Patients in the fenestrated group had 55% less total chest tube drainage (P=0.036), 41% shorter total hospitalization (P=0.018), and 67% fewer additional procedures in the postoperative period (P=0.006) than those in the nonfenestrated group.

CONCLUSIONS

Baffle fenestration performed at the time of Fontan surgery improves short-term outcome in standard-risk patients by decreasing pleural drainage, hospital length of stay, and need for additional postoperative procedures.

Transcatheter closure of fontan fenestrations using the Amplatzer septal occluder: initial experience and follow-up

We have recently used the Amplatzer septal occluder to close Fontan fenestrations. Between June 1998 and December 1999, 13 patients underwent transcatheter occlusion of their Fontan fenestrations. Systemic blood flow decreased significantly without a concomitant decrease in pulmonary blood flow. All residual shunts detectable by oximetry were at sites separate from those into which occlusion devices were implanted. One patient developed severe tricuspid regurgitation following the procedure requiring surgical removal of the device. At the last follow-up, all patients were doing well clinically. There were no shunts detectable through or around the devices by echocardiography. Our experience indicates that the location of the fenestration within the Fontan baffle is critical to avoiding device interference with other intracardiac structures. The Amplatzer septal occluder offers an effective means of transcatheter closure of Fontan baffle fenestrations. Although more experience is needed, our current follow-up data suggest that long-term outcomes will be favorable. Cathet. Cardiovasc. Intervent. 51:301-304, 2000.

Transcatheter closure of fenestrations and excluded hepatic veins after fontan: versatility of the Amplatzer device

BACKGROUND

The aim of this study was to evaluate the Amplatzer septal occluder (ASO) for transcatheter closure of fenestrations and excluded hepatic veins in patients after modified Fontan operations. Residual right-to-left shunts have improved surgical results of the Fontan operation. Shunt closure may eventually be desirable to eliminate hypoxemia and reduce risk of embolic complications.

METHODS AND RESULTS

Ten patients with hypoxemia caused by residual shunts after Fontan procedures were evaluated for closure. After favorable results of test occlusion, all shunts were closed with the use of the ASO. Eight ASOs were used to close fenestrations in 7 patients with 6F transvenous sheaths. Three ASOs were used to close excluded hepatic veins in 3 patients with 6F venous sheaths and transbaffle punctures. Fluoroscopy and transesophageal echocardiography were used to guide device placement. Device placement in all patients was successful. All shunts were closed by angiography after device placement. While breathing room air, systemic oxygen saturation rose from 87.9% +/- 3.0% to 96.3% +/- 0. 9% (P <.001) in the patients. There were no complications of the implant procedures and none noted in outpatient follow-up.

CONCLUSIONS

This experience suggests that the ASO is safe and effective for closing surgical shunts after Fontan procedures. The ASO design allows closure of excluded hepatic veins and has advantages over other devices in closure of fenestrations.