Right-to-Left Shunt Through Iatrogenic Atrial Septal Defect After MitraClip Procedure

ObjectivesThe aim of this study was to investigate the incidence, characteristics, hemodynamic conditions, and clinical significance of right-to-left (R-L) shunt through an iatrogenic atrial septal defect (iASD) after the MitraClip procedure.BackgroundR-L shunt through an iASD after the MitraClip procedure has not been well investigated.MethodsFrom 2014 to 2017, 385 consecutive patients with mitral regurgitation underwent the MitraClip procedure. iASD was assessed using intraprocedural transesophageal echocardiography. Right and left heart catheterization was used to assess the hemodynamic status of patients. All patients provided written informed consent for the procedure. All data for this study were collected from an established interventional cardiology laboratory database approved by the Cedars-Sinai Medical Center Institutional Review Board.ResultsR-L shunt was observed in 20 patients (5%). In 7 of these patients (35%), R-L shunt was accompanied by acute deoxygenation. Prevalence of severe tricuspid regurgitation (55% vs. 20%; p = 0.001), serum B-type natriuretic peptide (664 pg/ml [434 to 1,169 pg/ml] vs. 400 pg/ml [195 to 699 pg/ml]; p = 0.006), mean pulmonary artery pressure (38 mm Hg [34 to 45 mm Hg] vs. 29 mm Hg [22 to 37 mm Hg]; p < 0.001), and right atrial pressure (19 mm Hg [13 to 20 mm Hg] vs. 10 mm Hg [7 to 14 mm Hg]; p < 0.001) were significantly higher in patients with R-L shunt than in those with left-to-right shunt. Patients with R-L shunt also showed a more prominent reduction in the left atrial V-wave and mean pressure from baseline to post-procedure compared with those with left-to-right shunt (−22.8 ± 2.6 mm Hg vs. −11.8 ± 0.9 mm Hg [p = 0.002] and −7.9 ± 0.8 mm Hg vs. −4.0 ± 0.4 mm Hg [p = 0.003], respectively).ConclusionsR-L shunt through an iASD was observed in 5% of patients who underwent the MitraClip procedure and in one-third of patients with R-L shunt presented acute deoxygenation. Elevated right atrial pressure concomitant with pulmonary hypertension and significant reduction in left atrial pressure after MitraClip deployment were associated with R-L shunt.     

Right to left interatrial communications after the modified Fontan procedure: identification and management with transcatheter occlusion.

OBJECTIVE--To describe unusual venous communications from the right to the left atrium resulting in cyanosis after the modified Fontan procedure, and their management with transcatheter occlusion. METHODS--Between September 1992 and November 1994, eight patients were assessed for persistent cyanosis after a modified Fontan procedure. Desaturation was found to be caused by unusual venous shunts originating at atrial level, and transcatheter occlusion with either a double umbrella or coil was attempted. RESULTS--Three types of venous channels were identified. The first type of communication consisted of thin long tortuous channels originating from the right atrial wall, and draining into the left atrium through a capillary network. The second type of communication was in the superior anterior portion of the atrial baffle, incorporating the pectinate muscles of the right atrium, draining into the neoleft atrium. These channels were shorter and often fanned out into small vessels toward the right atrial appendage. In each instance, the shunts were in the superior suture line of a lateral tunnel modification of the Fontan procedure. The third type of communication originated from the inferior vena cava, connecting inferior phrenic veins to pericardial veins and subsequently to the left atrium, at or close to the ostium of the left pulmonary veins. Before device occlusion, the room air aortic oxygen saturation was 88(SD 4)% (range 84% to 94%), and increased to 95(3)% (range 91% to 100%) following occlusion (PL << 0.001). The mean right atrial pressure was 14(4)mm Hg and remained unchanged after occlusion. In six patients there was complete shunt obliteration, while in two both occluded with umbrella devices, a small residual leak persisted. No complication occurred during or immediately after catheterisation. CONCLUSIONS--Unusual venous communications can evolve after the Fontan procedure, resulting in the development or persistence of cyanosis. Some of these communications may be present preoperatively as normal veins draining into the right atrium, enlarging with the increased atrial pressure after surgery. These observations affect long term function after the Fontan procedure. Transcatheter occlusion of these communications is technically feasible and effective, although recurrence may occur.     

Large Right Atrial Myxoma Containing Gastric Heterotopia Presenting with Dyspnea and Bilateral Leg Edema due to Pulmonary Emboli and Cardiovascular Obstruction: The First Known Report of Gastric Heterotopia in the Cardiovascular System

A 52-year-old male presented with progressive dyspnea, bilateral leg edema, and elevated central venous pressure due to a large right atrial myxoma that caused vascular obstruction and pulmonary emboli. The myxoma contained gastric heterotopia. Other unusual features of this atrial myxoma included its large size, right atrial location, and attachment to the right atrial wall. Although gastric heterotopia has been reported throughout the gastrointestinal tract, and occasionally in other organs, this is the first report of gastric heterotopia in the cardiovascular system. This report confirms and extends previous reports of glandular elements or enteric glands within atrial, or cardiac, myxomas. The clinical presentation of the currently reported patient is explained as follows: the elevated central venous pressure resulted from cardiovascular obstruction and the dyspnea from multiple pulmonary emboli due to the large atrial myxoma. In this case, the clinical presentation was not attributable to the gastric heterotopia. The association of gastric heterotopia with atrial myxoma may, however, be clinically important because of the propensity of gastric heterotopia in the gastrointestinal tract to produce complications. The reported association may provide clues to the histogenesis of these two entities.     

Right coronary air embolism secondary to bowel infarction: a case report

An 81-year-old man with broad cerebral infarction presented with coronary air embolism secondary to bowel infarction and developed cardiogenic shock. Electrocardiography revealed ST elevation in the inferior leads and complete atrioventricular block with atrial fibrillation. Emergent angiography showed total occlusion of the right coronary artery without apparent thrombi. A multifunctional probe catheter was inserted into the right coronary artery for selective angiography. A moderate amount of air was aspirated from the catheter. The diagnosis was coronary air embolism. Coronary flow was restored after aspiration and normal saline flushing. Computed tomography showed massive portal venous gas. Emergent laparotomy disclosed broad bowel necrosis. The coronary air emboli may have originated from the portal vein and passed through the intrahepatic (portal to hepatic) shunt and patent foramen ovale(paradoxical embolization).     

A broken heart: right-to-left shunt in the setting of normal cardiac pressures

A patent foramen ovale (PFO) is a common structural cardiac variant occurring in approximately 30% of the general population. Patients are usually asymptomatic because the defect is flap-like and does not permit significant left-to-right shunting. However, pathological conditions that result in cardiac rotation or higher than normal right atrial pressures can reverse the normal left atrial to right atrial pressure gradient and cause a right-to-left shunt through a PFO. If the right-to-left shunt is persistent, systemic hypoxemia or paradoxical emboli may result. The present report describes a case of refractory hypoxemia in a critically ill patient with a PFO who had a right-to-left shunt with normal right-sided cardiac pressures.     

Mural thrombi of the right atrium and acute bacterial endocarditis complicating a LeVeen shunt

A cirrhotic woman with a LeVeen shunt developed right atrial thrombi, acute bacterial endocarditis, and a major pulmonary embolus. The right atrial mural thrombi and resultant pulmonary emboli arose as a result of the placement of the venous end of the LeVeen shunt within the right atrium. This untoward event must be added to the growing list of complications associated with the placement of such catheters.     

Left to right atrial shunting in tricuspid atresia.

In tricuspid atresia, an obligatory right to left shunt occurs at the atrial level. We have observed several patients with left to right interatrial shunts. Data from cardiac catheterisation in 40 consecutive patients were reviewed to determine the frequency and mechanism of left to right shunting in tricuspid atresia. An increase of 6% or more in oxygen saturation between the superior vena cava and the right atrium in two or more sets of saturations, representing a left to right shunt, was present in 29 out of 50 (58%) catheterisations in which the data were adequate. In most, the shunt was also seen cineangiographically in the laevophase. In only two catheterisations was an anatomical cause (ostium primum atrial septal defect in one and anomalous pulmonary venous return in the other) found. In the remaining 27 catheterisations, no anatomical cause was found. Age, Qp:Qs, and mean atrial pressure difference were similar between the shunt and non-shunt groups. In the shunt group right atrial "a" waves were equal to or higher than left atrial "a" waves and left atrial "v" waves were equal to or higher than right atrial "v" waves. Simultaneous pressure recordings (in one patient with left to right atrial shunt) from the left atrium and right atrium with isosensitised miniature pressure transducers mounted 5 cm apart showed (1) a higher pressure in the right atrium than in the left atrium during atrial systole and (2) a higher pressure in the left atrium than in the right atrium during atrial disatole. It is concluded that (a) left to right shunt across the atrial septum occurs frequently in tricuspid atresia and (b) the left to right shunt is the result of instantaneous pressure differences between the atria.     

A case of surgical treatment of multiple bilateral pulmonary arteriovenous fistulas in a senile patient

A 65-year-old woman was admitted with exertional dyspnea. She had a history of syncopal attack and cerebral infarction. On admission, her chest radiography ++ revealed two mass shadows in the right upper and lower fields. Pulmonary angiography and right heart catheterization were performed. Six arteriovenous fistulas in the right lung and five in the left were observed. The percent of R-L shunt was 51.5%. Because of exertional dyspnea, large shunt and history of cerebrovascular disorders, excision resection of two fistulas in right upper and middle lobes and right lower lobectomy were performed. Her symptoms improved and the percent of the R-L shunt markedly decreased after the operation. There is no sign of enlargement in size of the remaining arteriovenous fistulas.     

Blood flow pattern of the interatrial communication in patients with complete transposition of the great arteries: a pulsed Doppler echocardiographic study

We analyzed blood flow pattern in the interatrial communication in 24 patients with complete transposition of the great arteries (TGA). Eight had TGA with atrial shunt (group 1), nine had TGA with patent ductus arteriosus or ventricular septal defect (group 2), and seven had pulmonary arterial banding and Blalock-Taussig shunt (group 3). The flow pattern was determined at the site of atrial septal defect by Doppler echo beam directed as perpendicular to the septum as possible. The flow pattern was composed of a left-to-right (L-R) flow and right-to-left (R-L) flow. The turning point (T1) from the R-L to L-R flow occurred immediately after the initiation of the QRS on the electrocardiogram and was common in all groups. The other turning point (T2) from L-R to R-L occurred after the second heart sound (S2). The S2-T2 interval decreased on inspiration, indicating prolongation of the period of R-L flow. The minimum S2-T2 interval ranged from 20 to 70 (mean +/- SD 50 +/- 18) msec in group 1, from 70 to 130 (114 +/- 25) msec in group 2, and from 50 to 138 (75 +/- 29) msec in group 3. The maximum S2-T2 interval ranged from 48 to 110 (88 +/- 21) msec in group 1, from 140 to 235 (175 +/- 36) msec in group 2, and from 80 to 170 (111 +/- 30) msec in group 3.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bidirectional shunt in uncomplicated atrial septal defect.

The presence of right to left shunts at atrial level in 40 patients with an uncomplicated atrial septal defect was determined by measuring the pulmonary vein to systemic artery oxygen stepdown . In six patients (group 1) a sizeable right to left shunt was found: left atrial oxygen stepdown was greater than or equal to 0.7 vol%, mean right to left shunt 0.67 1/min/m2 (range 0.36-1.0), and arterial oxygen saturation between 84% and 90.5%. The patients in group 1 did not show any differences from those with left to right shunts alone (group 2) as regards sex, cardiac rhythm, heart rate, "a" wave and mean right atrial pressure, end diastolic right ventricular pressure, morphology of diastolic right ventricular pressure curves, pulmonary to systemic vascular resistance ratio, size of the defect, and coexistence of anomalous pulmonary venous drainage. Patients with coexisting right to left shunts were, however, significantly older and had smaller left to right shunts. Thus an appreciable number of patients with uncomplicated atrial septal defects have major right to left shunts which are unrelated to pulmonary hypertension or right heart failure. These shunts may be detected by the usual oximetric techniques and apparently develop with age, which suggests that they result from changes associated with chronic right volume overload.     

Bidirectional shunt in uncomplicated atrial septal defect

The presence of right to left shunts at atrial level in 40 patients with an uncomplicated atrial septal defect was determined by measuring the pulmonary vein to systemic artery oxygen stepdown . In six patients (group 1) a sizeable right to left shunt was found: left atrial oxygen stepdown was greater than or equal to 0.7 vol%, mean right to left shunt 0.67 1/min/m2 (range 0.36-1.0), and arterial oxygen saturation between 84% and 90.5%. The patients in group 1 did not show any differences from those with left to right shunts alone (group 2) as regards sex, cardiac rhythm, heart rate, "a" wave and mean right atrial pressure, end diastolic right ventricular pressure, morphology of diastolic right ventricular pressure curves, pulmonary to systemic vascular resistance ratio, size of the defect, and coexistence of anomalous pulmonary venous drainage. Patients with coexisting right to left shunts were, however, significantly older and had smaller left to right shunts. Thus an appreciable number of patients with uncomplicated atrial septal defects have major right to left shunts which are unrelated to pulmonary hypertension or right heart failure. These shunts may be detected by the usual oximetric techniques and apparently develop with age, which suggests that they result from changes associated with chronic right volume overload.     

Cerebral Embolism as a Cause of Stroke and Transient Ischemic Attack

The most frequent cause of stroke and transient ischemic attacks is cerebral embolism. Cardiogenic cerebral embolization is common among patients with any cause of atrial fibrillation (AF) but particularly in AF resulting from rheumatic and arteriosclerotic heart disease. Rare causes of cerebral embolism include fat entering the bloodstream after trauma, tumor cells arising from atrial myxomata, and gas embolism. Cerebral embolic infarctions and their sources of origin can now be confirmed during life by many invasive (I) and noninvasive (NI) procedures including computerized tomography (CT) scanning (NI), magnetic resonance imaging (MR) (NI), contrast angiography (I), digital subtraction angiography (I), magnetic resonance angiography (NI), carotid Doppler and transcranial Doppler (NI), and echocardiography (NI) without and with contrast. These tests visualize the following: embolic occlusions of small and large cerebral arteries, resultant cerebral infarctions in appropriate vascular territories, plaques within the aorta, subclavian, vertebral, and carotid arteries, and mural thrombi located within the heart and aortocephalic arteries. Transcranial Doppler monitoring of the middle cerebral artery detects both small (asymptomatic) and large (symptomatic) cerebral emboli, as well as transseptal cardiac shunting, which is a cause of paradoxical embolization. Holter monitoring detects episodic cardiac dysrhythmias not apparent during routine ECG. CT or MRI identify cerebral infarctions resulting from virtually all large cerebral emboli. Early recognition and identification of types of cerebral embolism are important because of the availability of effective prophylactic therapies.     

Cerebrovascular accidents after endoscopic obturation of esophageal varices with isobutyl-2-cyanoacrylate in 2 patients

We report 2 cases of cerebral stroke in cirrhotic patients following endoscopic obturation of esophageal varices with Isobutyl-2-Cyanoacrylate. In both cases, hemiplegia appeared several hours after the procedure. A brain CT scan showed radiodense material in the cerebral arteries due to dissemination of Isobutyl-2-Cyanoacrylate. One patient died, the other improved slowly. Different hypotheses may be raised: defectuous injection into the arterial circulation, systemic emboli via portopulmonary venous shunts, delayed polymerization of Isobutyl-2-Cyanoacrylate. Systemic emboli have been reported previously following percutaneous transhepatic obliteration of esophageal varices, suggesting portopulmonary venous shunts. In spite of these 2 complications, this procedure remains useful in stopping acute variceal bleeding and in preventing recurrent bleeding.     

Embolies coronaires secondaires à un thrombus adhérent de l’oreillette droite par un foramen ovale perméable

This observation relates to the discovery of native coronary paradoxical embolism secondary to thrombus adherent to the right atrium through a patent foramen ovale (PFO). A patient of 64 years, with a history of mitral regurgitation not followed, was hospitalized for acute respiratory distress due to a mitral insufficiency (MI) with a ruptured chordae and pulmonary embolism. Coronary angiography was performed and revealed two typical images of coronary embolism associated to a non-atheromatous coronary tree. The patient underwent a mitral valve replacement. After the establishment of cardiopulmonary bypass, adherent fibrin and cruoric thrombus of the right atrium and a PFO were found. The analysis of the valves did not reveal any arguments for infective endocarditis. A CT scan, performed as the patient remained unconscious after surgery, showed several cerebral infarcts. Paradoxical embolism coronary was diagnosed in front of the combination of adherent thrombus in the right atrium, pulmonary embolism and systemic coronary and cerebral embolism with a PFO. Coronary embolism rarely happens. It is mainly due to three causes: iatrogenic origin in most cases, direct causes due to micro emboli, particularly from infectious endocarditis and paradoxical embolic origin. There are two types of right atrial thrombus; the most common is the mobile thrombus from the peripheral venous system. The other one, which is more rare, is the adherent thrombus, which occurs in situ. Coronary embolism of paradoxical origin represents a small proportion of the causes of coronary embolism. However, this diagnosis must be considered.     

Recurrent Cerebral Abscess Secondary to a Persistent Left Superior Vena Cava

Cerebral abscess is a serious neurological condition that is often of unclear etiology. Management is usually medical therapy with or without direct drainage, and when patients have recurrent episodes a structural abnormality should be considered. Persistent left superior vena cava is an uncommon condition in the absence of other forms of congenital heart disease. This venous connection most often enters the right‐sided atrium through the coronary sinus but occasionally can connect directly to the left atrium near the wall between the orifice of the left pulmonary veins and left atrial appendage. This later congenital connection results in systemic venous return entering the left atrium directly. Thus allowing unfiltered, lower saturation blood entering the systemic system. This then places the patient at risk for systemic hypoxemia, paradoxical embolic events, and cerebral abscess. In our case report with recurrent cerebral abscess and a persistent left superior vena cava, we demonstrate when to consider this diagnosis, how to make the diagnosis, and a nonsurgical approach to repair the veno‐atrial shunt.     

Pulmonary hypertension complicating hepatocellular carcinoma

A case of primary liver cell carcinoma is presented in which tumor emboli to the pulmonary microvasculature resulted in pulmonary hypertension, documented by clinical, radiologic, electrocardiographic, and cardiac catheter studies. Emboli arose from tumor invading the portal vein and passed via a patent splenorenal shunt to the systemic venous and pulmonary arterial microvasculature. Despite a prolonged clinical course (20 mo) there was no radiologic evidence of pulmonary metastases and, histologically, tumor emboli were seen to undergo organization and recanalization.     

Venous thrombosis causing arterial embolization to the same limb through a patent foramen ovale

We describe a patient who presented with acute ischemia affecting the left lower limb. Because a transthoracic echocardiogram was abnormal, a transesophageal study was arranged. This demonstrated an atrial septal aneurysm and right-to-left shunting of contrast, raising the possibility of paradoxical embolism. The diagnosis was confirmed by contrast venography, which showed extensive thrombosis in the deep veins of the left thigh, and a ventilation-perfusion scan which was consistent with multiple pulmonary emboli. Among the lessons from this case was the finding that in patients with arterial embolism the likely origin of the embolus should be considered and, in the absence of common risk factors (atrial fibrillation, rheumatic heart disease, left ventricular dilatation, widespread atheroma), occult venous thrombosis and a right-to-left shunt should be sought. In this select group of patients, transesophageal echocardiography is significantly more sensitive than transthoracic study and should be the investigation of choice. Second, in the patient described in this report the clinical signs of deep venous thrombosis (DVT) were masked by the more prominent features of acute arterial ischemia. Without the incidental echocardiographic abnormality, it is likely that the important diagnoses of DVT, pulmonary embolism, and paradoxical embolism would not have been made.     

Embolies artérielles des membres

Arterial embolism of extremities results from the obstruction of the artery by a blood clot originating in the heart and travelling through the bloodstream. Rheumatismal causes have been progressively discarded drawing attention to atheromatosis. Apart from cardiac embolism, experience has shown the existence of emboli developing in other arteries and veins called paradoxical emboli. The aetiology of emboli has been supplemented by modern techniques, including the Holter electrocardiogram (ECG), transoesophageal echocardiography (TEE), computed tomography angiography (CTA) and magnetic resonance angiography (MRA). The role of arteriography is to be considered based on the degree of emergency and the condition of artery before blockage. Technology advances have also improved the treatment of emboli, together with the Forgarty's catheter which is still widely used aspiration thrombectomy can be achieved percutaneously. Catheter directed thrombolysis is another useful technique in the treatment of distal ischemia. However, in pathologic arteries, embolism often requires transluminal dilatation or by pass grafting. Nonetheless, the prognosis tends to remain severe due to a high risk of amputation and death related to the aetiology, terrain and other embolic localizations.     

Right atrial myxoma with right to left shunt and polycythemia presenting as congenital heart disease

A case of right atrial myxoma with right to left shunt is reported. A 56 year old woman had severe cyanosis, clubbing and polycythemia, and 2 episodes of transient cerebrovascular insufficiency, thus raising the possibility of paradoxical tumor emboli through an interatrial defect. Whereas routine chest fluoroscopy could only suggest the correct diagnosis, fluoroscopy with image intensification, phonocardiography and ultrasound cardiography were of great value in corroborating the hemodynamic and angiographic findings of tumor with shunt through a patent foramen ovale.     

Embolic stroke due to a left atrial thrombus two years after placement of an atrial septal defect closure device

A 29-year-old woman who had undergone closure of a secundum-type atrial septal defect using the Amplatzer device 2 years previously developed acute and progressive altered mentation. Initial clinical and imaging data confirmed the diagnosis of multiple cerebral, cerebellar and brain stem emboli, and infarcts. She was treated urgently with an intra-arterial thrombolytic agent with only minimal improvement. Transesophageal echocardiography revealed a large thrombus attached to the left atrial disc of the atrial septal defect occluder, which was the source of the emboli. In conclusion, this is the first reported case, to our knowledge, of disseminated cerebral emboli and infarctions as a late complication of transcatheter closure of a secundum-type atrial septal defect.