Patent foramen ovale: a cause of hypoxemia in patients on left ventricular support

We describe 2 patients who experienced right-to-left shunting during support with a left ventricular assist device as a result of patent foramen ovale. In the first patient, the patent foramen ovale was not found until autopsy. In the second patient, fluctuations in continuous mixed venous oxygen saturations caused us to suspect a patent foramen ovale, which was confirmed with transesophageal contrast echocardiography. We promptly repaired the defect and this patient survived. When patients on assist devices experience unexplained arterial hypoxemia, a patent foramen ovale should be considered. If a patent foramen ovale is found, surgical correction should be done early.     

Transcatheter closure of patent foramen ovale for hypoxemia during left ventricular assist device support.

A patent foramen ovale with right-to-left shunting was responsible, in part, for profound hypoxemia in a patient who required mechanical support with a left ventricular assist device for cardiogenic shock. The patent foramen ovale was detected with contrast transesophageal echocardiography, and the defect was closed successfully with a transcatheter septal defect closure device.     

Intermittent atrial level right-to-left shunt with temporary hypoxemia in a patient during support with a left ventricular assist device

We report a 56-year-old male patient developing hypoxemia after surgical replacement of infected valves of a left ventricular assist device (LVAD, Novacor) which had supported him during the previous 15 months. Contrast transesophageal echocardiography (TEE) revealed an atrial septal defect with intermittent right-to-left shunt across a patent foramen ovale. We postulate that the shunt detected in this patient occurred as a consequence of reduced pulmonary vascular compliance due to positive end-expiratory pressure (PEEP) and an increase of mean intrathoracic pressure. Furthermore, we hypothesize that synchronized LVAD operation exacerbates any potential right-to-left shunt due to the profound left ventricular unloading which occurs during LVAD support. In this first report of a right-to-left shunt from a previously unrecognized patent foramen ovale in a Novacor patient, the subsequent transient hypoxemia could be managed by avoiding PEEP of more than 3 mmHg, and mean airway pressure of more than 11 mmHg and by careful volume replacement in order to prevent the pump from completely emptying the left ventricle (LV) and the left atrium (LA). Thus, prior to every LVAD implantation a transesophageal contrast echocardiography with Valsalva maneuver should be performed to identify intracardiac right-to-left shunt.     

Transesophageal echocardiography as a guide for patient positioning before neurosurgical procedures in semi-sitting position

With an incidence of a patent foramen ovale in nearly one fourth of the normal population, neurosurgical procedures in the semi-sitting position are associated with the risk of paradoxical air embolism. The present study was undertaken to evaluate an anesthetic concept to detect a patent foramen ovale with the help of transesophageal echocardiography in anesthetized patients before neurosurgical procedures in the semi-sitting position. Transesophageal echocardiography was performed after induction of anesthesia before surgery to avoid additional physical and psychologic stress for the patients. Thirty-five neurosurgical patients scheduled for elective surgery in the semi-sitting position were examined with help of contrast transesophageal echocardiography. The data of the examined patients were analyzed with respect to efficiency, logistic efforts, and adverse events. Contrast transesophageal echocardiography was combined with a ventilation maneuver to increase right atrial pressure. A patent foramen ovale was detected in 3 of 35 patients. These patients were operated on in a supine position. Oral insertion of the echoprobe was possible in all patients without difficulties. A short-lasting hypertension was observed in 5 patients despite adequate analgesia and sedation. The average time of examination was 25 minutes. None of the patients showed paradoxical air embolism as judged by postoperative neurologic assessment. Contrast transesophageal echocardiography combined with a ventilation maneuver is an effective method in detecting a patent foramen ovale. Moreover, transesophageal echocardiography is a clinical guide to patient positioning. The method of anesthetic management presented to examine anesthetized patients immediately before surgery means less physical and psychologic stress for the patients and causes approximately a 30-minute delay of surgery.     

Improved technique to diagnose a patent foramen ovale during left ventricular assist device insertion

Diagnosis of a patent foramen ovale prior to left ventricular assist device placement can be quite difficult, and if missed may result in a significant hypoxemia due to a right to left shunt. We describe a simple and precise way to increase the diagnostic accuracy of patent foramen ovale detection prior to initiating cardiopulmonary bypass for left ventricular assist device placement.     

Opening of a foramen ovale during liver transplantation. The value of transesophageal echocardiography

A case is reported of a foramen ovale becoming patent during orthotopic liver transplantation (OLT). The patient had a hepatoma secondary to post-hepatitis cirrhosis. Monitoring included transesophageal echocardiography (TEE). A veno-venous shunt between the right femoral, portal and left axillary veins was used so as to maintain the venous return during portal and caval clamping. The patient's haemodynamic state remained quite stable throughout this period, and no vasoactive drug was required. Five min after graft reperfusion, pulmonary arterial pressure increased suddenly (mean PAP: 27 mmHg). TEE revealed paradoxical movements of the atrial septum. Colour coded Doppler ultrasound showed blood flowing from the right to the left atrium through a patent foramen ovale. Fifteen min later, mean PAP decreased (18 mmHg) and TEE no longer showed any flow between the two atria. Several studies have reported transient pulmonary hypertension after unclamping when the donor liver is reperfused. This could induce right ventricular failure, with transient inversion of the atrial pressure gradient, which, in turn, could result in a right-to-left shunt through a patent foramen ovale. TEE can monitor regional and overall left ventricular function as well as the atrial septum. This technique might therefore to be useful for cardiac monitoring during OLT.     

The detection of interatrial flow patency in awake and anesthetized patients: a comparative study using transnasal transesophageal echocardiography

The Valsalva maneuver in the awake patient and the ventilation maneuver in the tracheally intubated anesthetized patient are two provocation methods to detect a patent foramen ovale (PFO) by means of contrast transesophageal echocardiography. In 60 patients undergoing posterior fossa surgery, a contrast agent was administered via a peripheral vein during a Valsalva maneuver immediately before anesthesia induction, followed by central venous administration during a ventilation maneuver in the same patients when anesthetized and endotracheally intubated. We evaluated both maneuvers with a 32-element monoplane transnasal transesophageal echocardiography probe to trace the atrial flow of the contrast agent in a 90 degrees bicaval view. A maneuver was rated positive when more than four bubbles appeared in the left atrium during the first three cardiac cycles after intrathoracic pressure release. The right atrial cross-sectional area before pressure release, and the peak septal excursion during atrial contrast opacification, were measured. McNemar's test was used to assess a paired dichotomous response on the two maneuvers for a significant difference. In 56 patients, the ventilation maneuver was significantly (P < 0.037) more often positive for PFO (n = 14) than the Valsalva maneuver (n = 7). Although there was no difference in the methods regarding the peak septal excursion, the mean right atrial area before pressure release was significantly smaller during the ventilation maneuver than during the Valsalva maneuver (11.2 +/- 3.1 cm(2) vs 14.4 +/- 3.3 cm(2), n = 42, P < 0.05). In the patients with a positive ventilation, but a negative Valsalva maneuver, the discrepancy was even larger (10.9 +/- 4.4 cm(2) vs 16.3 +/- 4.2 cm(2), n = 7, P < 0.001). We conclude that the ventilation maneuver is superior to the Valsalva maneuver in detecting PFO. Our data suggest that a peak pressure of 30 cm H(2)O during the ventilation maneuver achieves a more pronounced reduction in right atrial load and allows right atrial pressure to exceed left atrial pressure when intrathoracic pressure is released. IMPLICATIONS: A controlled ventilation maneuver in anesthetized patients immediately before posterior fossa surgery may be superior to the preoperative Valsalva maneuver in detecting a patent foramen ovale by contrast transesophageal echocardiography. This approach identifies patients at high risk for paradoxic embolism, but it is not practical for preoperative identification of patients who might benefit from patent foramen ovale closure before surgery.     

Surgical management of complications after transcatheter closure of an atrial septal defect or patent foramen ovale

OBJECTIVE: During recent years, transcatheter closure has become an alternative to operations for the treatment of atrial septal defects and patent foramen ovale. However, this procedure may be unsuccessful or complicated and requires surgical treatment. METHODS: We retrospectively analyzed the outcomes of patients who needed surgical treatment after failed or complicated transcatheter closure of an atrial septal defect or a patent foramen ovale. RESULTS: Between April 1994 and March 1999, 124 patients were treated with transcatheter closure of an atrial septal defect or a patent foramen ovale at our institution. We report the results of 10 (8%) patients of this series who required operations after transcatheter closure attempts. In 8 of these 10 patients a significant shunt caused by malposition or dislocation of the device persisted, leading to surgical closure of the defect. In 2 patients injury of the femoral artery at the puncture site required surgical repair. In one patient the device had to be removed surgically from the iliac vein after retraction. One patient died of left ventricular perforation after dislocation of the device and several surgical attempts to close the left ventricular rupture. All other patients recovered well. CONCLUSION: An operation was required after transcatheter closure of an atrial septal defect or a patent foramen ovale in 8% of patients. After device complications, the atrial septal defect and the patent foramen ovale can still successfully be closed surgically with good results and low morbidity. However, serious complications like cardiac perforation may have a fatal outcome. Residual shunt, dislocation, or vascular complications are the most frequent problems that require surgical interventions.     

Removal of a left atrial thrombus adherent to a patent foramen ovale occluder

A 62-year-old man presented with bilateral thromboembolic occlusion of the lower leg arteries 8 months after closure of a patent foramen ovale with an Amplatzer patent-foramen-ovale occluder (AGA Medical Corporation, Plymouth, MN). Then he developed an acute myocardial ischemia. A left heart catheter revealed thromboembolic occlusion of the right coronary artery, and echocardiography demonstrated a thrombus attached to the device within the left atrium. Cerebral computer tomography showed a new ischemic lesion. In an emergency procedure, the device and the left atrial thrombus were removed, the septal defect was closed, and a coronary artery bypass grafting was performed. The patient was discharged from the hospital in stable condition.     

Transcatheter closure of patent foramen ovale for hypoxemia during left ventricular assist device support

The diagnosis of a patent foramen ovale (PFO) is a dynamic process and it is based on the detection of blood shunting at the atrial level. Only under abnormal physiologic conditions, such as with a left ventricular assist device (LVAD), when right atrial pressure (RAP) exceeds left atrial pressure (LAP) the PFO may cause hypoxemia due to a right-to-left shunt. We report the closure of a PFO using a transcatheter approach in a patient on LVAD support.     

Pulmonary thromboembolism with floating thrombus trapped in patent foramen ovale

A 39-year-old man was hospitalized with symptoms of acute deep vein thrombosis, and computed tomography showed that he had pulmonary thromboembolism. Transthoracic echocardiography showed a large, right atrial thrombus and transesophageal echocardiography showed migrating thrombus trapped in a patent foramen ovale and extending all the way up to the ascending aorta. He underwent surgical embolectomy under cardiopulmonary bypass. At the conclusion of the operation, repeat transesophageal echocardiography examination revealed fresh but small thrombus in the right atrium. This continued entry of thrombi into the heart was further managed with fluoroscopy-guided insertion of a retrievable inferior vena cava filter through the internal jugular vein in the operating room itself.     

Contrast echocardiography and transcranial Doppler sonography for detection of a patent foramen ovale

We report the case of a patient, in whom a patent foramen ovale was detected. For the detection of a patent foramen ovale simulation of Valsalva's manoeuvre with a positive airway pressure of 20 cm H2O was applied. Change of ventilation manoeuvre by ventilation with positive airway pressure of 35/30/15 cm H2O at a tidal volume of 1200 ml make a distinct increase in passage of contrast medium from the right to the left atrium. These findings were detected by contrast transesophageal echocardiography and indirectly by transcranial Doppler sonography and were reproducible. This may stress the importance of preoperative screening of patent foramen ovale in patients to be operated on in the sitting position. Contrast echocardiography and the ventilatory manoeuvre with high airway pressure and PEEP might increase the detection rate of patent foramen ovale with a right to left shunt during general anaesthesia.     

Acute left atrial thrombus after recombinant factor VIIa administration during left ventricular assist device implantation in a patient with heparin-induced thrombocytopenia

We present a patient with end-stage heart failure and heparin-induced thrombocytopenia Type II, who required cardiopulmonary bypass (CPB) during a repeat implantation of a left ventricular assist device for long-term circulatory support. Bivalirudin was selected for anticoagulation during CPB, with concomitant infusion of aprotinin, in an effort to ameliorate blood loss. Nonetheless, profuse bleeding after CPB required massive transfusion of packed red blood cells, multiple coagulation factors, and platelets. Because of persistent bleeding, a single dose of recombinant factor VIIa (rFVIIa, 7.2 mg) was administered as rescue therapy. Within minutes, a large left atrial thrombus was detected by transesophageal echocardiography. We believe this is the first documentation of acute left atrial thrombus formation immediately after a single dose of recombinant factor VIIa administration during a left ventricular assist device implantation.     

Transesophageal echocardiography in patients with mechanical circulatory assistance.

Transesophageal echocardiography was used to assess myocardial function and to detect complications after mechanical circulatory support for 8 patients with cardiogenic shock. In 3 of 8 patients, serial transesophageal echocardiography documented improvement of systolic ventricular function, and it was possible to wean these 3 patients from the ventricular assist device. In all patients, transesophageal echocardiography added clinically important information including the extent of left and right ventricular dysfunction (6 patients), presence of atrial or ventricular thrombus (5 patients), presence of pericardial effusion or clot (2 patients), and verification of the position of the intravascular device (1 patient). Thus, transesophageal echocardiography may provide clinically useful information regarding both the underlying cardiac disease and potential complications from the mechanical circulatory assistance.     

A suspected case of paradoxical renal embolism through the patent foramen ovale

We experienced a case of cryptogenic renal infarction in a previously healthy 60-year-old man. He had no systemic atherosclerotic changes. Holter monitoring revealed no atrial fibrillation. Transthoracic echocardiography showed no thrombus. Because the onset occurred while he was swinging a golf club (a similar maneuver to holding the breath), further examination was performed with a view to detecting paradoxical embolism through the foramen ovale. A positive bubble test with the Valsalva maneuver during transesophageal echocardiography led to the diagnosis of patent foramen ovale (PFO). This was a suspected case of paradoxical embolism through a PFO leading to renal infarction.     

Intraoperative assessment of cardiac function with transesophageal echocardiography during the Batista operation

We experienced anesthetic management for six cases of the Batista operation and measured cardiac function before and after cardiopulmonary bypass (CPB) with transesophageal echocardiography. In the successful three patients, left ventricle ejection fraction and ejection time were maintained over 25% and 200 msec after CPB, respectively. In the other three resulting in implantation of left ventricular assist device, ejection fraction remained below 20% and ejection time under 200 msec after CPB. Intraoperative transesophageal echocardiography may be useful not only for monitoring of cardiac function but also for the prediction of prognosis.     

A rare case of impending paradoxical embolism with a complex patent foramen ovale

A 68-year-old woman, who presented with pulmonary embolism, was diagnosed as having an impending paradoxical thromboembolism by transthoracic and transesophageal echocardiography, which revealed an entrapped thrombus in the atrial septum. The patient underwent surgery for thromboembolectomy. A patent foramen ovale (PFO) appeared as a tunnel with three openings into the left atrium; one opening located close to the antero-superior left atrial wall and two small atrial septal defects of a septum primum. A thrombus was trapped at two small atrial septal defects. This was a rare case of impending paradoxical embolism with complex morphology of PFO.     

Three-dimensional transesophageal echocardiography in the diagnosis of atrial septal aneurysm with patent foramen ovale in a patient with ventricular septal defect

We present a case of a rare combination of ventricular septal defect and atrial septal aneurysm (ASA) with a patent foramen ovale (PFO) in a 57-year-old female. She was referred to our hospital for the treatment of irregular palpitation and exertional shortness of breath. Two-dimensional transesophageal echocardiography (2D-TEE) with color Doppler imaging demonstrated an ASA with two lines of shunt flows. Three-dimensional transesophageal echocardiography (3D-TEE) could clearly visualize the morphology of the PFO in the surgeon??s view and demonstrated a crescent-shaped opening of the PFO. 3D-TEE appears to be a more accurate modality than 2D-TEE for the assessment of PFO.     

Cerebral microembolism diagnosed by transcranial Doppler during total knee arthroplasty: correlation with transesophageal echocardiography.

BACKGROUND: Tourniquet deflation following total knee arthroplasty (TKA) frequently results in release of emboli into the pulmonary circulation. Small emboli may gain access to the systemic circulation via a transpulmonary route or through a patent foramen ovale. This study examined the incidence of cerebral microembolism after tourniquet release by transcranial Doppler (TCD) ultrasonography and its correlation with echogenic material detected in the left atrium. METHODS: Twenty-two adult patients (9 men, 13 women) undergoing TKA were studied with simultaneous TCD ultrasonography and transesophageal echocardiography. Data were recorded after anesthesia induction and tourniquet inflation and during tourniquet deflation. Emboli counts were performed manually off-line. Echogenic material in the left atrium was qualitatively assessed and correlated with TCD data. Patients were examined postoperatively for focal neurologic deficits. RESULTS: Fifteen patients had unilateral TKA (six left, nine right) and seven had bilateral TKA. Cerebral emboli were detected in 9 of 15 patients (60%) with unilateral TKA and in 4 of 7 patients (57%) with bilateral TKA. Echogenic material was identified in the left atrium in eight patients (two through a patent foramen ovale and six from the pulmonary veins). Emboli counts were significantly higher in patients with bilateral TKA compared with those with unilateral TKA (P<0.05). Duration of tourniquet time in patients with emboli was longer only during bilateral TKA (P<0.05). All patients with echogenic material in the left atrium detected by transesophageal echocardiography had emboli as assessed by TCD ultrasonography. No focal neurologic deficits were identified. CONCLUSIONS: Cerebral microembolism occurs frequently during tourniquet release, even in the absence of a patient foramen ovale. This passage most likely occurs through the pulmonary capillaries or the opening of recruitable pulmonary vessels.     

Acute pulmonary embolism and a patent foramen ovale: analysis of atrial right-to-left shunting by biphasic transcardiopulmonary thermodilution curves

A 69-year-old woman with an acute pulmonary embolism developed an intracardiac right-to-left shunt, which was diagnosed early on and quantified via biphasic transcardiopulmonary thermodilution curves. With transesophageal echocardiography, a patent foramen ovale and an impressive atrial right-to-left shunt were visualized.