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

Risk factors and complications associated with intra-operative or post-operative identification of a PFO in cardiac surgery patients: A cohort study

Introduction

It is unknown whether patent foramen ovale (PFO) reopening in the peri-operative setting of cardiac surgery affects the risk for stroke and post-operative outcomes.

Methods

We performed a single-center, retrospective study based on a prospectively collected database in a tertiary cardiac surgery center. Using logistic regression, we assessed risk factors of PFO finding around surgery and subsequent clinical complications.

Results

Between January 2007 and July 2019, 11034 patients who underwent cardiac surgery in our center were included. A total of 233 patients (2.1%) presented a finding of PFO including 138 per-operative disclosures and 95 post-operative finding for hypoxemia. In the whole cohort, the mean age was 68.4 ± 11.5 years including 73.9% of men. Post-operative PFO finding was associated with more ischemic strokes compared with per-operative finding and control group [7(7.4%) vs. 3(2.2%) vs. 236(2.2), respectively; p = 0.003]. Moreover, patients with post-operative PFO reopening experienced a higher rate of pneumonia, reintubation, and longer length of stay in the ICU. Post-operative reopening of PFO, but not per-operative finding, was independently associated with ischemic strokes {adjusted odds-ratio = 3.5, 95% confidence interval (CI) [1.6-7.8]; p = 0.002}. Other variables associated with stroke incidence included age, mitral valve surgery, and ascending aorta surgery. Per- or post-operative PFO closure was associated with reduced adverse respiratory outcomes and a trend of the lower cerebral ischemic event.

Conclusion

Patent foramen ovale finding incidence in peri-operative cardiac surgery care was rare (2%) but post-operative finding of PFO was associated with a increased risk of ischemic strokes, worsened respiratory outcomes, and prolonged hospitalization.

Risk of Perioperative Stroke in Patients with Patent Foramen Ovale: A Systematic Review and Meta-Analysis

BACKGROUND

Patent foramen ovale (PFO) is a common congenital cardiac abnormality. Risk of stroke increases perioperatively; however, the association of PFO with perioperative stroke risk remains unclear. We conducted a systematic review to inform the risk of perioperative stroke in patients with PFO undergoing surgery.

METHODS

EMBASE, MEDLINE, and Cochrane databases were searched from inception to January 2020. We described methods used for establishing PFO and perioperative stroke diagnosis. We conducted meta-analyses to obtain pooled estimates for risk of stroke in patients with and without PFO in different surgical populations.

RESULTS

Ten articles with a total of 20,858,011 patients met the eligibility criteria. Prevalence of PFO ranged from 0.06-1.4% based on ICD code diagnosis and 10.4-40.4% based on echocardiography diagnosis. Perioperative stroke was observed in 0-25% of patients with PFO, and 0-16.7% without PFO. Studies that use echocardiography to diagnose PFO found no association between PFO and perioperative stroke. Studies that used ICD codes, found strong association but were highly heterogenous. PFO was not associated with a risk of perioperative stroke in cardiac and transplant surgeries. While the adjusted odds ratios for stroke were substantial for orthopedic, general, genitourinary, neuro, and thoracic surgeries (with PFO status established based on ICD codes), data heterogeneity and quality of data create significant uncertainty.

CONCLUSION

In conclusion, PFO is likely a risk factor for perioperative stroke in select types of surgeries. However, this is based on a very low-quality evidence. Rigorous, prospective studies are needed to further investigate this relationship.

[Intraoperative vascular air embolism : Evidence for risks, diagnostics and treatment]

The entry of gases into the vascular system is called vascular air embolism (VAE). The blocking of the pulmonary circulation by VAE can lead to fulminant right-sided heart failure and cardiocirculatory arrest. A VAE can occur at any time if there is an open connection between the environment and a venous vessel with subatmospheric pressure. This situation occurs during ear nose throat surgery, hip surgery, surgery of the lesser pelvis or breast surgery, if the surgical field is above the level of the heart; however, a VAE can also occur during routine tasks, such as insertion or removal of a central venous catheter or during endoscopic procedures with the insufflation of gas.Because during these procedures VAE is not the main focus of the anesthesia or surgery personnel, in such situations its sudden unexpected occurrence can have severe consequences. In contrast, in cardiac surgery or neurosurgery the risk of intraoperative VAE is much better known. In procedures with a higher risk of a clinically relevant VAE, a patent foramen ovale should be ruled out by preoperative transesophageal echocardiography (TEE). Intraoperatively TEE is the most sensitive procedure not only to detect a VAE but also to visualize the clinical expression, e.g. acute right heart overload.The avoidance of an initial and repeated air embolism is the primary measure to minimize the incidence and severity of VAE.Intraoperatively the following measures should be undertaken: excellent communication between anesthesia and surgery personnel with predetermined actions, maintenance of normal volume, patient positioning with minimal difference in height between heart and head, state of the art surgical technique with closure of potential air entry sites, sufficient detection of air by TEE, repeated jugular vein compression during neurosurgery, intraoperative Trendelenburg positioning of the patient during persisting or clinically evident VAE, differentiated adjustment of ventilatory settings and catecholamine treatment, aspiration of the blood-air mixture (air lock) at the junction of the superior vena cava and right atrium through a large bore central venous line and keeping check of the coagulation status.

Patent foramen ovale repair at the time of double lung transplantation: Necessary or not?

INTRODUCTION

Patient foramen ovale (PFO) is a common and often incidental intraoperative finding during lung transplantation (LTx). We sought to characterize the potential outcomes related to the decision making of whether the PFO was repaired or left unrepaired.

METHODS

We retrospectively evaluated bilateral LTx recipients between 2005 and 2015 from our prospective database. Incidence of postoperative stoke, 90-day mortality, and overall survival was compared between the PFO-positive and PFO-negative groups, and secondly compared between repaired PFO (rPFO) and non-repaired PFO (nrPFO) groups.

RESULTS

A total of 831 LTx recipients were analyzed: 185 PFO-positive (140 nrPFO, 45 rPFO) and 646 PFO-negative. Study groups were similar with regard to age and comorbidity. The presence of PFO was not associated with a difference in postoperative stroke (P = .89) or 90-day mortality (P = .64). In patients with PFO, intraoperative repair resulted in a lower, but non-significant rate of stroke (0% vs 5%; P = .20) and no difference in mortality (P = .26). As expected, PFO and PFO repair were both associated with a higher incidence of cardiopulmonary bypass utilization, but no difference in pump-related complications.

CONCLUSIONS

The protective effect of PFO repair remains unclear. However, it is not associated with an increased incidence of stroke or postoperative mortality following LTx.

Unusual cause of hypoxemia after automatic implantable cardioverter-defibrillatorleads extraction

The indication of pacemaker/AICD removal are numerous. Serious complication can occur during their removal, severe tricuspid regurgitation is one of the complication. The occurrence of PFO is not uncommon among adult population. Shunting across PFO in most circumstance is negligible, but in some necessitates closure due to hypoxemia. We report a case of 62 year old man, while undergoing AICD removal, had an emergency sternotomy for cardiac tamponade. Postoperatively, he experienced profound hypoxemia refractory to oxygen therapy. Transthoracic Echocardiogram was performed to rule out intracardiac shunts at an early stage, but it was difficult to obtain an good imaging windows poststernotomy. A small pulmonary emboli was noted on CTPA, but was not sufficient to account for the level of hypoxemia and did not resolve with anticoagulation. Transesophageal echocardiogram showed flail septal tricuspid valve with severe TR and bidirectional shunt through large PFO. Patient was posted for surgery, tricuspid valve was replaced and PFO surgically closed. Subsequently, patient recovered well ad was discharged to home. Cause of hypoxemia might be due to respiratory or cardiac dysfunction. But for hypoxemia refractory to oxygen therapy, transoesophageal echocardiogram should be always considered and performed early as an diagnostic tool in post cardiac surgical patients.

Impending paradoxical embolism: have we lost the clot?

Impending paradoxical embolism is a rare diagnosis that requires urgent treatment. We present a case where surgical thromboembolectomy was undertaken. The thrombus vanished from view on transesophageal ultrasound and was presumed to have undergone embolisation while bypass was established. Unexpectedly, it was found tangled in the superior vena cava cannula apertures.

Propensity score models in observational comparative effectiveness studies: cornerstone of design or statistical afterthought?

Propensity score models are increasingly used in observational comparative effectiveness studies to reduce confounding by covariates that are associated with both a study outcome and treatment choice. Any such potentially confounding covariate will bias estimation of the effect of treatment on the outcome, unless the distribution of that covariate is well-balanced between treatment and control groups. Constructing a subsample of treated and control subjects who are matched on estimated propensity scores is a means of achieving such balance for covariates that are included in the propensity score model. If, during study design, investigators assemble a comprehensive inventory of known and suspected potentially confounding covariates, examination of how well this inventory is covered by the chosen dataset yields an assessment of the extent of bias reduction that is possible by matching on estimated propensity scores. These considerations are explored by examining the designs of three recently published comparative effectiveness studies.

Patent foramen ovale: Its significance in anesthesia and intensive care: An illustrated case

Patent foramen ovale (PFO) is defined as a valve-like opening at the level of foramen ovale or between septum primum and secundum without evidence of the anatomical defect. Paradoxical embolism (PDE) is an embolus passing through a defect PFO leading to end-organ dysfunction. PDE in septic shock is not yet reported in the literature. A 49-year male presented to the emergency department with shortness of breath since one day and pain in the left side of the chest. Chest x0 -ray revealed middle-left lobe pneumonia with pleural effusion; he was started on Co-amoxiclav, and admitted to the ward. After 6 h, his chest pain suddenly significantly increased difficulty in breathing and his oxygen saturation dropped. X-ray of the chest showed left pneumothorax, chest drain was inserted and he was intubated. He became hemodynamically unstable with maximum ventilatory support and noradrenalin. On day 4, he was found to have new pansystolic murmur in the tricuspid area. An echocardiogram revealed global hypokinesia, two mobile thrombi in the right atrial cavity, and PFO. It was noticed that his right toe had blackish discoloration. An angiogram showed occlusion of the right superficial femoral artery and immediately an embolectomy. On day 11, he was transferred to the ward. PDE needs a high index of suspicion in septic shock patients with ARDS. PDE requires PEEP adjustment, early anticoagulation, and thromboprophylaxis.

Severe hypoxaemia with a left ventricular assist device in a minipig model with an undiagnosed congenital cardiac disease

We describe the placement of a left ventricular assist device (LVAD) in a pig with spontaneously occurring atrial septal defect (ASD) (incidental finding) that created a right-left cardiac shunt, with subsequent severe hypoxaemia. Early diagnosis was critical in order to prevent end-organ damage due to hypoxaemia. Adequate monitoring alerted us to the deterioration in oxygenation, haemodynamics and cerebral oxygen metabolism. This forced us to change the level of assistance provided by the pump, and thus dramatically correct this impairment. Necropsy revealed an ostium secundum ASD. In conclusion, if hypoxaemia presents after implementation of an LVAD, the presence of a right-left shunt must be ruled out. The first step must be a judicious reduction in assist device flow to minimize intracardiac shunting. Subsequently, atrial septal closure of the defect should be considered. We report an experimental model of severe hypoxaemia after placement of an LVAD as part of a larger research project.

Intraoperative echocardiography in valvular heart disease: an evidence-based appraisal

Intraoperative (IO) transesophageal echocardiography (TEE) is widely used for assessing the results of valvular heart disease (VHD) surgery. Epiaortic ultrasonography (EAU) has been recommended for prevention of perioperative strokes. To what extent does high-quality evidence justify the widespread use of these imaging modalities? In March 2009, we searched MEDLINE (PubMed and OVID interfaces) and EMBASE for studies published in English using database-specific controlled vocabulary describing the concepts of IOTEE, cardiac surgery, VHD, and EAU. We found no randomized trials or studies with control groups assessing the impact of IOTEE in VHD surgery. Pooled analysis of 8 observational studies including 15,540 patients showed an average incidence of 11% for prebypass surgical changes and 4% for second pump runs, suggesting that patients undergoing VHD surgery may benefit significantly from IOTEE, particularly from postcardiopulmonary bypass IOTEE in aortic repair and mitral repair and replacement, but less so in isolated aortic replacement. Further available indirect evidence was satisfactory in the test accuracy and surgical quality control aspects, with low complication rates for IOTEE. The data supporting EAU included 12,687 patients in 2 prospective randomized studies and 4 nonrandomized, controlled studies, producing inconsistent outcome-related results. Despite low-quality scientific evidence supporting IOTEE in VHD surgery, we conclude that indirect evidence supporting its use is satisfactory and suggests that IOTEE may offer considerable benefit in valvular repairs and mitral replacements. The value of IOTEE in isolated aortic valve replacement remains less clear. Evidence supporting EAU is scientifically more robust but conflicting. These findings have important clinical policy and research implications.