Transesophageal echocardiography detection of air embolism during endoscopic surgery and validity of hyperbaric oxygen therapy: Case report.

INTRODUCTION: Air embolism has the potential to be serious and fatal. In this paper, we report 3 cases of air embolism associated with endoscopic medical procedures in which the patients were treated with hyperbaric oxygen immediately after diagnosis by transesophageal echocardiography. In addition, we systematically review the risk factors for air embolism, clinical presentation, treatment, and the importance of early hyperbaric oxygen therapy efficacy after recognition of air embolism. PATIENT CONCERNS: We present 3 patients with varying degrees of air embolism during endoscopic procedures, one of which was fatal, with large amounts of gas visible in the right and left heart chambers and pulmonary artery, 1 showing right heart enlargement with increased pulmonary artery pressure and tricuspid regurgitation, and 1 showing only a small amount of gas images in the heart chambers. DIAGNOSES: Based on ETCO2 and transesophageal echocardiography (TEE), diagnoses of air embolism were made. INTERVENTIONS: The patients received symptomatic supportive therapy including CPR, 100% O2 ventilation, cerebral protection, hyperbaric oxygen therapy and rehabilitation. OUTCOMES: Air embolism can causes respiratory, circulatory and neurological dysfunction. After aggressive treatment, one of the 3 patients died, 1 had permanent visual impairment, and 1 recovered completely without comorbidities. CONCLUSIONS: While it is common for small amounts of air/air bubbles to enter the circulatory system during endoscopic procedures, life-threatening air embolism is rare. Air embolism can lead to serious consequences, including respiratory, circulatory, and neurological impairment. Therefore, early recognition of severe air embolism and prompt hyperbaric oxygen therapy are essential to avoid its serious complications.

A multiscale model of vascular function in chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by recurrent or unresolved pulmonary thromboemboli, leading to perfusion defects and increased arterial wave reflections. CTEPH treatment aims to reduce pulmonary arterial pressure and reestablish adequate lung perfusion, yet patients with distal lesions are inoperable by standard surgical intervention. Instead, these patients undergo balloon pulmonary angioplasty (BPA), a multisession, minimally invasive surgery that disrupts the thromboembolic material within the vessel lumen using a catheter balloon. However, there still lacks an integrative, holistic tool for identifying optimal target lesions for treatment. To address this insufficiency, we simulate CTEPH hemodynamics and BPA therapy using a multiscale fluid dynamics model. The large pulmonary arterial geometry is derived from a computed tomography (CT) image, whereas a fractal tree represents the small vessels. We model ring- and web-like lesions, common in CTEPH, and simulate normotensive conditions and four CTEPH disease scenarios; the latter includes both large artery lesions and vascular remodeling. BPA therapy is simulated by simultaneously reducing lesion severity in three locations. Our predictions mimic severe CTEPH, manifested by an increase in mean proximal pulmonary arterial pressure above 20 mmHg and prominent wave reflections. Both flow and pressure decrease in vessels distal to the lesions and increase in unobstructed vascular regions. We use the main pulmonary artery (MPA) pressure, a wave reflection index, and a measure of flow heterogeneity to select optimal target lesions for BPA. In summary, this study provides a multiscale, image-to-hemodynamics pipeline for BPA therapy planning for patients with inoperable CTEPH. NEW & NOTEWORTHY This article presents novel computational framework for predicting pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension. The mathematical model is used to identify the optimal target lesions for balloon pulmonary angioplasty, combining simulated pulmonary artery pressure, wave intensity analysis, and a new quantitative metric of flow heterogeneity.

Chimney reconstruction provides a wider subaortic space and reduces the risk of pulmonary artery compression in the Norwood-type aortic arch reconstruction without patch supplementation.

OBJECTIVES: Pulmonary artery (PA) compression by the neoaorta is a serious complication after the Norwood-type palliation (NP) for hypoplastic left heart syndrome. Either excess patch tailoring or limited use of autologous tissue may cause narrowing of the subaortic space. The chimney technique could theoretically provide a wide subaortic space. METHODS: Twenty-nine patients with both pre- and post-NP computed tomography data available of the 37 consecutive patients who underwent NP in our institution were reviewed. Arch height, arch width, sinus of Valsalva diameter, area under the neoaortic arch and arch angle were measured. These patients were divided according to the neo-arch reconstruction technique, chimney reconstruction technique (CR) or conventional direct reconstruction technique (DR). RESULTS: Median age and weight at NP were 2.1 months and 3.5 kg, respectively. Twenty-two patients underwent previous bilateral PA banding. During NP, 17 CR and 12 DR were performed. Four patients in the DR group developed PA compression. No neoaortic arch dilatation was found in either group. Post-NP arch width, area under the neo-arch and the arch angle were significantly larger in the CR group. Pre-NP arch height was significantly smaller in DR patients with PA compression than in those without. CONCLUSIONS: The chimney technique decreased the risk of PA compression and provided a wider subaortic space and a less acute arch angle. This technique had no short-term effect on the neoaortic root. Small preoperative arch height is a potential risk factor for PA compression in DR, and the chimney technique could be an effective solution.

The role of balloon pulmonary angioplasty and pulmonary endarterectomy: Is chronic thromboembolic pulmonary hypertension still a life-threatening disease?

BACKGROUND: The management of non-operable chronic thromboembolic pulmonary hypertension (CTEPH) has evolved with the availability of balloon pulmonary angioplasty (BPA) and pulmonary vasodilators. We launched the BPA program in 2011. The aim was to analyze the survival and treatment efficacy of our CTEPH treatment program in the modern management era. METHODS AND RESULTS: We retrospectively reviewed data from 143 consecutive CTEPH patients diagnosed from January 2011 (i.e. after the availability of BPA) to December 2019. Of forty-one patients who underwent pulmonary endarterectomy (PEA), 25 underwent additional BPA (Combination group) and the others were treated with only PEA (PEA group). Ninety patients underwent BPA (BPA group). The remaining 12 patients did not undergo any interventional treatments. The 1- and 5-year survival rates of operated patients (n = 41) were 97.4% and 90.0%, compared to 96.9% and 86.9% in not-operated patients (n = 102), respectively (p = 0.579). There was no mortality in the Combination group. Mean pulmonary artery pressure after treatments in the PEA only, Combination, and BPA only groups was 20.5 ± 6.7, 17.9 ± 4.9, and 20.7 ± 4.6 mmHg, respectively (p = 0.067, one-way ANOVA). Percent decrease of pulmonary vascular resistance in each treatment groups was -73.7 ± 11.3%, -74.3 ± 11.8%, and - 54.9 ± 22.5%, respectively (p < 0.01, one-way ANOVA). CONCLUSION: There was no significant difference in long-term survival between operated and not-operated CTEPH. Moreover, the Combination approach might have the potential to introduce notable improvements in the prognosis of CTEPH. BPA and PEA appear to be mutually complementary therapies in the modern management era.

Precision diagnosis and therapy of a case of brain abscesses associated with asymptomatic pulmonary arteriovenous fistulas.

BACKGROUND: Brain abscesses, a severe infectious disease of the CNS, are usually caused by a variety of different pathogens, which include Streptococcus intermedius (S. intermedius). Pulmonary arteriovenous fistulas (PAVFs), characterized by abnormal direct communication between pulmonary artery and vein, are a rare underlying cause of brain abscesses. CASE PRESENTATION: The patient was a previous healthy 55-year-old man who presented with 5 days of headache and fever. Cerebral magnetic resonance imaging (MRI) suggested a brain abscess. Thoracic CT scan and angiography demonstrated PAVFs. Aiding by metagenomic next-generation sequencing (mNGS) of the cerebrospinal fluid (CSF) sample which identified S. intermedius as the causative pathogen, the patient was switched to the single therapy of large dose of penicillin G and was cured precisely and economically. CONCLUSIONS: It is an alternative way to perform mNGS to identify causative pathogens in patients with brain abscesses especially when the results of traditional bacterial culture were negative. Further thoracic CT or pulmonary angiography should also be undertaken to rule out PAVFs as the potential cause of brain abscess if the patient without any known premorbid history.

Mapping and Ablation of Arrhythmias from Uncommon Sites (Aortic Cusp, Pulmonary Artery, and Left Ventricular Summit).

Despite advances in our understanding of the relevant anatomy and mapping and catheter ablation techniques of idiopathic outflow tract ventricular arrhythmias, challenging sites for catheter ablation remain the aortic cusps, pulmonary artery, and notably the left ventricular summit. A systematic approach should be used to direct mapping efforts efficiently between endocardial, coronary venous, and epicardial sites. Foci at the left ventricular summit, particularly intraseptal and at the inaccessible epicardial region, remain difficult to reach and when percutaneous techniques fail, surgical ablation remains an option but with risk of late coronary artery stenosis.

Successful Conservative Treatment of Mycotic Pulmonary Artery Aneurysms Caused by MRSA Bacteremia.

Mycotic pulmonary artery aneurysms (MPAAs) are rare and life-threatening with currently no recommended treatment strategies. In this report, we describe a successfully treated case of ventricular septal defect in an 11-month-old girl who developed bacteremia, infective endocarditis, and MPAA caused by methicillin-resistant Staphylococcus aureus (MRSA). We first started vancomycin, gentamycin, and panipenem-betamipron for infective endocarditis but switched to teicoplanin and arbekacin on day 3 after initiating treatment because bacteremia persisted, and vancomycin minimum inhibitory concentration was relatively high at 2 mg/L. Although we added clindamycin on day 5 and fosfomycin on day 7, MRSA bacteremia persisted, and we finally added daptomycin at 10 mg/kg per day on day 8, whereupon the bacteremia subsided within a day. Although the bacteremia subsided, the patient developed septic pulmonary embolisms and septic arthritis on her left knee. We continued daptomycin but switched the concomitant drug to linezolid, trimethoprim-sulfamethoxazole, and rifampicin on day 11. After several repeats of puncture and lavage of her knee joint, she became afebrile on day 16. Computed tomography scans taken on day 32 revealed right pulmonary artery MPAAs. She was treated with long-term multidrug therapy, and MPAAs were absent on subsequent computed tomography scans on day 184. Multidrug therapy mainly based on daptomycin could be a possible salvage therapy for refractory MRSA bacteremia with high vancomycin minimum inhibitory concentration. Conservative treatment should be selectively considered as a treatment option for clinically stable MPAA instead of surgical and endovascular treatment.

State of the art: utility of multi-energy CT in the evaluation of pulmonary vasculature.

Multi-energy computed tomography (MECT) refers to acquisition of CT data at multiple energy levels (typically two levels) using different technologies such as dual-source, dual-layer and rapid tube voltage switching. In addition to conventional/routine diagnostic images, MECT provides additional image sets including iodine maps, virtual non-contrast images, and virtual monoenergetic images. These image sets provide tissue/material characterization beyond what is possible with conventional CT. MECT provides invaluable additional information in the evaluation of pulmonary vasculature, primarily by the assessment of pulmonary perfusion. This functional information provided by the MECT is complementary to the morphological information from a conventional CT angiography. In this article, we review the technique and applications of MECT in the evaluation of pulmonary vasculature.

A Rare Case of Cerebral Air Embolism Caused by Pulmonary Arteriovenous Malformation After Removal of a Central Venous Catheter.

Cerebral air embolism following central venous catheter (CVC) removal is extremely rare. We report a case of cerebral air embolism with loss of consciousness after removal of CVC caused by pulmonary arteriovenous malformation (PAVM). Computed tomography revealed air bubbles in the internal carotid arteries along the sulci in the cerebral hemispheres, as well as a PAVM. The cerebral air embolism was treated with hyperbaric oxygen and intravenous thrombolytic therapy, and transcatheter embolization of the PAVM was performed. When inserting/removing CVC in a patient with a small PAVM, treatment of the PAVM, irrespective of its size, could prevent the type of complication that occurred in our present case.

Elimination of CT-detected gas bubbles derived from decompression illness with abdominal symptoms after a short hyperbaric oxygen treatment in a monoplace chamber: a case report.

We report the case of a 54-year-old male compressed-air worker with gas bubbles detected by computed tomography (CT). He had complained of strong abdominal pain 30 minutes after decompression after working at a pressure equivalent to 17 meters of sea water for three hours. The initial CT images revealed gas bubbles in the intrahepatic portal vein, pulmonary artery and bilateral femoral vein. After the first hyperbaric oxygen treatment (HBO2 at 2.5 atmospheres absolute/ATA for 150 minutes), no bubbles were detected on repeat CT examination. The patient still exhibited abdominal distension, mild hypesthesia and slight muscle weakness in the upper extremities. Two sessions of U.S. Navy Treatment Table 6 (TT6) were performed on Days 6 and 7 after onset. The patient recovered completely on Day 7. This report describes the important role of CT imaging in evaluating intravascular gas bubbles as well as eliminating the diagnosis of other conditions when divers or compressed-air workers experience uncommon symptoms of decompression illness. In addition, a short treatment table of HBO2 using non-TT6 HBO2 treatment may be useful to reduce gas bubbles and the severity of decompression illness in emergent cases.

Mapping and ablation of anteroseptal atrial tachycardia in patients with congenitally corrected transposition of the great arteries: implication of pulmonary sinus cusps.

AIMS: We sought to investigate focal atrial tachycardias (ATs) in patients with congenitally corrected transposition of the great arteries (ccTGA). METHODS AND RESULTS: We identified three cases of focal ATs with ccTGA from 2007 to 2015. The clinical findings, electrocardiography, electrophysiological features, and ablation were reported. All three cases had {S,L,L}-type ccTGA. The AT P waves shared the following features: narrow in width, positive in leads I and aVL, and negative/positive in lead V1. All ATs had focal activation pattern with early activation at the anteroseptal area, and further mapping demonstrated earliest atrial activation (EAA) inside the pulmonary sinus cusps (PSCs), especially the right PSC. In Cases 1 and 2, double potentials were recorded at the EAA sites. Conduction delay between the two potentials during atrial extrastimulus was observed. After successful ablation, the second potential during sinus rhythm was further delayed in Case 1 and was eliminated in Case 2. However, only one potential was recorded in Case 3. All three cases were successfully managed by ablating the sites with EAA, which preceded the P-wave onset by 60, 80, and 42 ms, respectively. During ablation, no junctional rhythm was observed. Incomplete left bundle branch block was induced during mapping in Case 1, but no other complications occurred. All patients were free from tachycardia during follow-up periods of 36, 7, and 5 months, respectively. CONCLUSION: Anteroseptal AT in patients with ccTGA could be eliminated by ablation inside the PSC.

A randomized pilot study on the effect of niacin on pulmonary arterial pressure.

BACKGROUND: Niacin induces the release of vasodilating prostaglandins, for which receptors are present within the pulmonary arterial circulation. We hypothesized that immediate-release niacin would reduce right ventricular systolic pressure in patients with pulmonary hypertension in a randomized, double-blinded, single-dose provocation study. METHODS: We recruited inpatient subjects with a Doppler echocardiogram showing a peak tricuspid regurgitation (TR) jet velocity of 2.7 m/s or greater, and who were free of known pulmonary vascular disease. Subjects were randomized in a 1:2:2 ratio to receive a single dose of either placebo, niacin 100 mg or niacin 500 mg, respectively. TR jet velocities were measured immediately before, and 1 hour post dose, corresponding to peak niacin absorption and prostaglandin release. The primary endpoint was the change in mean TR jet velocity measured over ten successive cardiac cycles. RESULTS: The baseline mean estimated right ventricular systolic pressure (RVSP) for all 49 subjects (25 male) was 51.9 ± 12.1 mm Hg. The primary endpoint of mean change in TR jet velocity was 0.016 ± 0.065 m/s in the placebo group, compared to -0.017 ± 0.065 m/s with niacin 100 mg, and -0.063 ± 0.038 m/s with niacin 500 mg (P = 0.63). The change in maximum estimated RVSP across the three drug groups was 0.2 ± 1.6 mm Hg, -1.3 ± 1.8 mm Hg and -2.2 ± 1.2 mm Hg (P = 0.62). In exploratory pairwise analysis in the high-dose niacin group (500 mg), the reduction in mean RVSP was from 50.9 ± 9.4 mm Hg to 48.7 ± 10.0 mm Hg (P = 0.09). CONCLUSIONS: A single dose of immediate-release niacin (100 mg or 500 mg) had no significant effect on RVSP 1 hour post administration. A nonsignificant dose-dependent trend for a modest reduction in RVSP, most notable in the 500 mg group, was noted. (ISRCTN number 12353191, registered April 23, 2015).

Ubiquitous myocardial extensions into the pulmonary artery demonstrated by integrated intracardiac echocardiography and electroanatomic mapping: changing the paradigm of idiopathic right ventricular outflow tract arrhythmias.

BACKGROUND: Idiopathic ventricular arrhythmias of left bundle branch block inferior axis morphology are usually localized to the right ventricular outflow tract (RVOT), presumably below the pulmonic valve (PV). However, the PV location is usually not confirmed by direct visualization. METHODS AND RESULTS: Intracardiac echocardiography was used to visualize and tag the PV annulus, which was then integrated with 3-dimensional voltage maps of the RVOT. Distances were measured from the furthest extent of myocardial signal (bipolar voltage ≥1.5 mV) to the PV annulus. This was performed in 24 control patients and 24 prospective patients with RVOT arrhythmias. Myocardial signal beyond the PV was found in 92% of controls and 88% of RVOT arrhythmia patients (P=1.000). Average myocardial extension was further on the septal side than on the free wall side for control patients (5.6 mm; interquartile range [IQR], 3.6-7.7, versus 1.7 mm; IQR (-)0.1 to (+)4.0; P=0.002) and RVOT arrhythmia patients (5.7 mm; IQR, 2.7-7.7, versus 1.4 mm; IQR, (-)0.8 to (+)4.8; P=0.004). Eleven (46%) RVOT arrhythmia foci were localized beyond the valve in the pulmonary artery (median 8.2 mm above PV; IQR, 6.6-10.3 mm); these locations were confirmed as supravalvular by direct intracardiac echocardiography visualization. CONCLUSIONS: Myocardial voltage extension into the pulmonary artery in humans is ubiquitous and can be demonstrated in vivo using 3-dimensional integrated intracardiac echocardiography to localize the PV. These extensions frequently serve as origins of presumed RVOT arrhythmias; intracardiac echocardiography localization of the PV allows reclassification of these as pulmonary arterial arrhythmias.

Observation of increased venous gas emboli after wet dives compared to dry dives.

INTRODUCTION: Testing of decompression procedures has been performed both in the dry and during immersion, assuming that the results can be directly compared. To test this, the aim of the present paper was to compare the number of venous gas bubbles observed following a short, deep and a shallow, long air dive performed dry in a hyperbaric chamber and following actual dives in open water. METHODS: Fourteen experienced male divers participated in the study; seven performed dry and wet dives to 24 metres' sea water (msw) for 70 minutes; seven divers performed dry and wet dives to 54 msw for 20 minutes. Decompression followed a Bühlmann decompression procedure. Immediately following the dive, pulmonary artery bubble formation was monitored for two hours. The results were graded according to the method of Eftedal and Brubakk. RESULTS: All divers completed the dive protocol, none of them showed any signs of decompression sickness. During the observation period, following the shallow dives, the bubbles increased from 0.1 bubbles per cm ² after the dry dive to 1.4 bubbles per cm ² after the wet dive. Following the deep dives, the bubbles increased from 0.1 bubbles per cm ² in the dry dive to 2.4 bubbles per cm ² in the wet dive. Both results are highly significant (P = 0.0001 or less). CONCLUSIONS: The study has shown that diving in water produces significantly more gas bubble formation than dry diving. The number of venous gas bubbles observed after decompression in water according to a rather conservative procedure, indicates that accepted standard decompression procedures nevertheless induce considerable decompression stress. We suggest that decompression procedures should aim at keeping venous bubble formation as low as possible.

Effect of L-arginine or L-citrulline oral supplementation on blood pressure and right ventricular function in heart failure patients with preserved ejection fraction.

BACKGROUND: The effect of L-arginine and L-citrulline on blood pressure and right ventricular function in heart failure patients with preserved ejection fraction (HFpEF) is unknown. We have therefore evaluated, in a randomized clinical trial, the effect of these aminoacids in chronic outstanding and stable patients with HFpEF. METHODS AND RESULTS: All patients underwent an echocardiogram and radioisotopic ventriculography rest/exercise, and were randomized in a consecutive manner to the L-arginine group (n = 15; 8 g/day); and the citrulline malate group (n = 15; 3 g/day). The duration of follow-up was two months. The principal echocardiographic finding was a statistically significant decrease in pulmonary artery pressure in the L-arginine (56.3 ± 10 vs 44 ± 16.5 mm Hg, p < 0.05) and the citrulline (56.67 ± 7.96 vs 47.67 ± 8.59 mm Hg, p < 0.05) groups. Duration on treadmill and right ventricular ejection fraction post exercise increased, while diastolic and systolic artery pressure decreased significantly in both groups. There were no other statistically significant differences between the groups. CONCLUSIONS: Administration of L-arginine and citrulline to patients with HFpEF improved right ventricular function by increasing right ventricular ejection fraction, and probably decreasing systolic pulmonary artery pressure.

Ventilation/Perfusion SPECT for diagnostics of pulmonary embolism in clinical practice.

AIM: The aim of this retrospective study is to illustrate clinical utility and impact of pulmonary embolism (PE) diagnostics of up to date Ventilation/Perfusion SPECT (V/P (SPECT)) applying holistic interpretation criteria. MATERIAL AND METHODS: During a 2-year period 2328 consecutive patients referred to V/P(SPECT) for clinically suspected PE were examined. Final diagnosis was established by physicians clinically responsible for patient care. To establish the performance of V/P(SPECT) negative for PE, patients were followed up by medical records for 6 months. RESULTS: Ventilation/Perfusion SPECT was feasible in 99% of the patients. Data for follow-up were available in 1785 patients (77%). PE was reported in 607 patients (34%). Normal pattern was described in 420 patients (25%). Pathology other than PE such as a pneumonia, left heart failure, obstructive lung disease, tumour was described in 724 patients (41%). Report was nondiagnostic in 19 patients (1%). Six cases were classified as falsely negative because PE was diagnosed at follow-up and was fatal in one case. Six cases were classified as falsely positive because the clinician decided not to treat. In 608 patients with final PE diagnosis, 601 patients had positive V/P(SPECT) (99%). In 1177 patients without final PE diagnosis 1153 patients had negative V/P(SPECT) (98%). CONCLUSIONS: Holistic interpretation of V/P(SPECT,) yields high negative and positive predictive values and only 1% of nondiagnostic findings and was feasible in 99% of patients. It is a responsibility and a challenge of nuclear medicine to provide optimal care of patients with suspected PE by making V/P(SPECT) available.