The role of paradoxical arterial emboli of the extremities

Isquemia arterial aguda de las extremidades: ¿cómo abordarla?

La isquemia arterial aguda de las extremidades se define como la interrupción abrupta del flujo sanguíneo a determinado tejido, lo cual afecta la integridad, la viabilidad de la extremidad, o ambas. Las causas son múltiples y pueden resumirse en dos procesos fisiopatológicos, trombóticos o embólicos, con lo que se puede establecer el pronóstico y el tratamiento según su causa. El cuadro sindrómico es variable, y típicamente, se identifica con las cinco “P” de Pratt (pain, pallor, pulselessness, paralysis and paresthesia); se cuenta con múltiples ayudas diagnósticas, pero la arteriografía sigue siendo el método estándar para el diagnóstico. Con el advenimiento de los avances tecnológicos y los procedimientos vasculares, el salvamento de las extremidades ha venido en aumento y ha disminuido la extensión de las amputaciones, lo cual conlleva una mayor tasa de rehabilitación y de reincorporación a la vida social.

A Case Demonstrating the Ribaroxaban Therapy for Paradoxical Embolism

A paradoxical embolism is defined as a systemic arterial embolus due to passage of a venous thrombus through a right to left shunt. In recent years, vitamin K antagonists and aspirin are used as anticoagulant medications for the secondary prevention of paradoxical embolism. We describe a case of subacute right upper limb ischemia due to paradoxical embolism. We first started treatment with urokinase, intravenous (IV) injection and unfractionated heparin (continuous IV). As her condition and the serum D-dimer level showed improvement, we started catheterization on day 7 after admission; however the right brachial artery thrombus did not disappear. For her outpatient care, based on the viewpoint of providing rapid anticoagulation therapy within the therapeutic range, having longest periods of initial intensive therapy we chose the treatment using ribaroxaban. Recanalization of her right brachial artery was achieved with this therapy. Here, we report the effective results of initial intensive therapy using ribaroxaban for paradoxical embolism.

Clinical, hemodynamic, and intracardiac echocardiographic characteristics of secundum atrial septal defects-related paradoxical embolism in adulthood

BACKGROUND

Paradoxical embolism associated with secundum atrial septal defect (sASD) is a relatively rare but well-known occurrence. The purpose of our study is to report the clinical, hemodynamic, and anatomical features assessed by intracardiac echocardiography (ICE) of sASD as related to paradoxical embolism.

METHODS

Five hundred thirty-seven patients (mean age 48 ± 19.0 years) admitted for transcatheter repair of interatrial shunts were enrolled in a prospective registry over a 10-year period (September 2003-September 2013). All patients underwent transesophageal echocardiography, complete right and left catheterization, prior to the device-based procedure. ICE was performed in all patients in order to investigate the interatrial septum anatomy and to monitor device implantation. These results were compared with the data of patients with patent foramen ovale (PFO) patients and nonemboligenous sASD admitted at the same time period.

RESULTS

Twenty-four patients (6.2%) out of 386 who underwent transcatheter repair for paradoxical embolism had a secundum ASD. The defects were cribrosus in 41.6% (10/24). All single sASD (58.3%) had a peculiar anatomical feature a so-called flat elliptical shape with a major axis of 7.6 ± 2.4 and minimal axis of 2.5 ± 1.6 mm. Patients with sASD-related paradoxical embolism had a higher frequency of deep venous thrombosis compared to PFO patients. In comparison to nonemboligenous sASD, such patients had lower mean pulmonary pressure and smaller defects.

CONCLUSION

sASD related to paradoxical embolism had peculiar clinical, hemodynamic, and anatomical characteristics, which classified such defects in the middle of the spectrum between nonemboligenous secundum ASD and PFO.

Ischemic stroke caused by paradoxical embolism after an unsuccessful transcatheter atrial septal defect closure procedure: a word of caution

Transcatheter device closure of atrial septal defect (ASD) has become a well-accepted alternative to surgical repair. Serious complications of transcatheter ASD closure are rare, but when they occur, devastating consequences may result. Herein, we present the case of a 4-year-old girl who had an ischemic stroke caused by a presumptive paradoxical embolism after an unsuccessful transcatheter ASD procedure and in whom subsequent venous color Doppler showed deep venous thrombosis (DVT) of the right lower extremity. The risk factors that predisposed to paradoxical cerebral embolism and DVT in this patient are discussed, and the literature is reviewed.

The Incidental Finding of a Patent Foramen Ovale During Cardiac Surgery: Should It Always Be Repaired? A Core Review

With the increased use of intraoperative transesophageal echocardiography, patent foramen ovale (PFO) has become a common finding during heart surgery. This finding presents a difficult dilemma for cardiac surgeons, since the impact of intraoperatively diagnosed PFOs on postoperative outcome is unknown. Changes in the surgical plan required for closure of a PFO subject the patient to the possibility of additional risk. On the other hand, a decision to not close a PFO exposes the patient to unclear immediate and long-term consequences. Deciding whether or not to close a PFO currently depends on the clinicians' personal preferences, the probability of intraoperative and postoperative hypoxemia, and any anticipated deviation from the initial surgical plan. Most clinicians agree that an intraoperatively diagnosed PFO must be closed when surgery leads to a high risk of hypoxemia (e.g., left ventricular assist devices placement, heart transplantation); should be closed in most cases when minimal deviation from the initial surgical plan is needed for PFO closure (e.g., mitral valve or tricuspid valve surgeries); and probably, should be closed during heart surgeries performed without atriotomy and bicaval cannulation when the risk of perioperative or remote PFO-related complications is increased. The recent development of percutaneous methods of PFO closure provides a valuable backup for those cases when PFO is not closed and postoperative hypoxemia or other complications may be attributable to the uncorrected PFO.

The simultaneous occurrence of deep vein thrombosis and pulmonary and arterial embolization

INTRODUCTION

A 45-year-old female presented with 8 hours of right lower extremity pain and dyspnea. She was tachycardic and her right lower extremity was dusky, cold, and pulseless.

DISCUSSION

Computerized tomography of the venous and arterial systems revealed massive pulmonary embolism and right lower extremity arterial and left lower extremity venous thromboses. Management included intra-arterial thrombolytics, right lower extremity arterial embolectomy, and anticoagulation. Echocardiogram revealed a patent foramen ovale (PFO) with a right-to-left shunt.

CONCLUSION

We hypothesize that our patient developed deep venous thrombosis that led to major pulmonary embolization and increased right-sided pressures. In the setting of a patent foramen ovale, a later venous embolus transversed the PFO and lodged in the femoral artery. Our case illustrates the importance of a high index of suspicion for a paradoxical embolus in patients with arterial thrombosis.

Paradoxical arterial emboli causing acute limb ischemia in a patient with essential thrombocytosis

Acute arterial occlusion can be the result of acute thrombosis or systemic embolism. Paradoxical embolism of a venous thrombosis through a right-to-left shunt is an important cause of acute limb ischemia. We describe a young patient with acute limb ischemia who was found to have multiple deep venous thromboses causing arterial embolization through a patent foramen ovale. Essential thrombocytosis was found to be the risk factor for venous thromboses in this patient. The patient was managed with embolectomy and anticoagulation along with chemotherapeutic cytoreduction of platelet count. This case illustrates the importance of considering the systemic embolism as a cause of acute arterial occlusion. The presence of a hypercoagulable status such as chronic myeloproliferative disorder does not eliminate the possibility of systemic embolism in the event of acute arterial occlusion. Patients presenting with acute limb ischemia should be evaluated for embolic sources. The presence of deep venous thrombosis in such a patient should prompt the evaluation for a patent foramen ovale.

Etiology of peripheral arterial thromboembolism in young patients

BACKGROUND

No prior studies have explored the etiology of peripheral arterial thromboembolic events (PATE) in younger patients. Therefore, we analyzed the sources of these events in patients <50 years of age over a recent 10-year period. Diagnostic and work-up strategies will be proposed based on the presence of cardiac or atherosclerotic risk factors.

PATIENTS AND METHODS

The sources of emboli were classified as (1) conventional (cardiac or arterioarterial), (2) unconventional, or (3) unknown. A statistical analysis of risk factors that, if absent, would suggest an unconventional cause was performed. Risk factors included those for cardiac and atherosclerotic disease: coronary artery disease (CAD), valvular disease, smoking, arrhythmia, hypertension, or diabetes mellitus.

RESULTS

Overall, 51 patients were identified. Twenty-nine patients (57%) had unconventional causes (8 paradoxical emboli, 4 possible paradoxical emboli, 12 hypercoagulable states, 3 white clot syndromes, and 2 cervical ribs), 17 (33%) had conventional causes, and 5 (10%) were unknown. When the number of cardiac risk factors was < or =1, excluding smoking, the probability of a conventional source was zero, in contrast to 100% if the number of risk factors was >1. When the following risk factors were absent, there were significantly more unconventional than conventional sources of emboli (P < 0.001): smoking (100% versus 0%), CAD (93% versus 7%), arrhythmias (83% versus 17%), hypertension (93% versus 7%), and diabetes mellitus (81% versus 19%). Patients with a conventional source were significantly older (44 versus 38 years).

CONCLUSIONS

The "unconventional" causes of PATE were responsible for a higher percentage of cases in young patients. An analysis of the number of risk factors was useful in predicting which patients suffered embolic events from conventional sources, with the critical number being >1 (excluding smoking). Therefore, when younger patients present with PATE, and are found to have < or =1 identifiable cardiac risk factor, their work-up should be directed toward the unconventional sources first.