Recurrence of Pulmonary Arteriovenous Malformation after Embolization in Patients with Pulmonary Hypertension.

PURPOSE: To evaluate the correlation between pulmonary hypertension (PH) and post-embolization pulmonary arteriovenous malformation (PAVM) recurrence. MATERIALS AND METHODS: With IRB approval the records of 377 patients with PAVMs evaluated at single HHT center of excellence between January 1, 2013, and September 10, 2023, were retrospectively reviewed. PAVMs embolized during this time-period were evaluated for recurrence. Patients and PAVMs not treated during this time-period were excluded. Growth of previously untreated PAVMs was not considered recurrence. Patients without chest CT follow-up were excluded. General demographics, HHT status as defined by genetic testing or Curacao criteria, presence of PH, history of smoking, anemia, and liver AVMs was documented. Odds ratio and stratified analysis was calculated to assay the correlation between PAVM recurrence, PH and possible confounders. RESULTS: A total of 151 patients with PAVMs were treated during the study period, including 438 PAVMs, for which follow-up was available. This included 106 patients with definite, 31 doubtful, and 14 possible HHT. The presence of pulmonary hypertension was significantly associated with both PAVM recurrence by patient (OR: 8.13, 95% CI 3.50 - 19.67) and by lesion (OR: 4.07, 95% CI 2.14 - 7.91). Multivariate analysis demonstrated that this correlation was independent of several variables including HHT status, smoking history, presence of liver AVMs, and anemia. CONCLUSION: There is a high correlation between pulmonary hypertension and PAVM recurrence, likely due to high pulmonary artery pressures causing recanalization. Pulmonary hypertension may suggest the need for shorter surveillance intervals.

Use of Transparent Film Dressing to Facilitate Mask Ventilation in Bearded Patients.

BACKGROUND: Mask ventilation is a critical airway procedure made more difficult in the bearded patient. OBJECTIVE: We sought to objectively investigate whether application of transparent cling film (TegadermTM; 3M Healthcare, Maplewood, MN) over a beard in the operating room improves the quality of mask ventilation. METHODS: This was a randomized crossover trial of bearded adult patients undergoing surgery. Exclusions included emergency procedures, American Society of Anesthesiologists physical status classification > 3, a documented history of difficult mask ventilation, and body mass index (BMI) > 50. Transparent cling film was applied snuggly over the lower face with a 2- to 3-cm slit cut over the mouth after anesthesia induction. Mask ventilation performed by an anesthesiology resident, anesthesiology assistant, or anesthesiology assistant student and standardized to a thenar-eminence grip without use of airway adjuncts in a sniffing position. Standardized pressure-controlled ventilations were delivered via an anesthesia machine. A calibrated external pneumotachograph was used to measure delivered and returned tidal volumes from which raw and percent air leak were calculated. A clinically significant difference was determined a priori to be 15%, necessitating the enrollment of 25 patients. RESULTS: Of 25 subjects, 96% were men with a mean ± SD BMI of 29.3 ± 6. Seventeen (68%) had a full beard and 8 (32%) had a partial beard. The mean ± SD leakage was 48% ± 26% for transparent cling film vs. 46% ± 20% without its application, which was not significantly different (p = 0.67). CONCLUSIONS: The use of transparent cling film to cover the lower half of the bearded face did not have an impact on the ability or efficacy to perform mask ventilation in the operating room setting. CLINICALTRIALS: gov, Number NCT04274686.

Flow-Induced Shear Stress Primes NLRP3 Inflammasome Activation in Macrophages via Piezo1.

The NLRP3 inflammasome is a crucial component of the innate immune system, playing a pivotal role in initiating and regulating the body's inflammatory response to various pathogens and cellular damage. Environmental stimuli, such as temperature, pH level, and nutrient availability, can influence the behavior and functions of innate immune cells, including immune cell activity, proliferation, and cytokine production. However, there is limited understanding regarding how mechanical forces, like shear stress, govern the intrinsic inflammatory reaction, particularly the activation of the NLRP3 inflammasome, and how shear stress impacts NLRP3 inflammasome activation through its capacity to induce alterations in gene expression and cytokine secretion. Here, we investigated how shear stress can act as a priming signal in NLRP3 inflammasome activation by exposing immortalized bone marrow-derived macrophages (iBMDMs) to numerous physiologically relevant magnitudes of shear stress before chemically inducing inflammasome activation. We demonstrated that shear stress of large magnitudes was able to prime iBMDMs more effectively for inflammasome activation compared to lower shear stress magnitudes, as quantified by the percentage of cells where ASC-CFP specks formed and IL-1ß secretion, the hallmarks of inflammasome activation. Testing this in NLRP3 and caspase-1 knockout iBMDMs showed that the NLRP3 inflammasome was primarily primed for activation due to shear stress exposure. Quantitative polymerase chain reaction (qPCR) and a small-molecule inhibitor study mechanistically determined that shear stress regulates the NLRP3 inflammasome by upregulating Piezo1, IKKß, and NLRP3. These findings offer insights into the mechanistic relationship among physiological shear stresses, inflammasome activation, and their impact on the progression of inflammatory diseases and their interconnected pathogenesis.

Pulmonary artery pseudoaneurysms: a single-center experience of endovascular occlusion.

The technique and outcomes of pulmonary artery pseudoaneurysm (PAP) embolization was retrospectively evaluated in 13 patients undergoing 14 PAP embolizations between January 2014 and September 2023. The etiology of the PAP was iatrogenic (4/13), tumor (3/13), chronic lung (2/13), idiopathic (2/13) and mycotic (2/13). Clinical presentation was massive hemorrhage (6/13), incidental (4/13), and non-massive hemoptysis (3/13). The average PAP size was 13.5 mm. Coil embolization of the PAP sac was performed in all but two extenuating cases (11/13). Follow-up of 12 patients over an average 5.3-months showed persistent occlusion in all cases. There were no major adverse events attributed to the embolization. Five out of ten patients with procedures performed at least one year before this study were noted to be deceased after an average seven-month time. PAPs of various etiologies may be safely and effectively treated by occluding the aneurysm inflow, outflow, and sac.

Twenty-Seven-Year Retrospective Review of Hemoptysis from Systemic Collaterals Following Pulmonary Arteriovenous Malformation Embolization.

OBJECTIVE: To determine the prevalence of hemoptysis secondary to post-embolization systemic collaterals and review the recurrence rate and treatment outcomes. METHODS: The records of 930 patients with PAVM (801 with known or possible HHT), from a single HHT center between July 2, 1996 and July 22, 2021, were searched for a single lifetime episode of hemoptysis secondary to post-embolization systemic collaterals. Embolization was performed with permanent particles or gelatin slurry. Clinical features and treatment outcomes of identified patients were reviewed. RESULTS: Twenty-eight embolization procedures have been performed in 9 patients with post-PAVM embolization systemic artery collateral reperfusion. This included 8 patients with known HHT. Permanent particles were used in 5 cases and gelatine slurry was used in 19 cases. Due to the recurrence of hemoptysis, four patients required four embolizations each, two patients required three embolizations and two patients required two embolizations. Chronic unresolving hemoptysis was the presentation in 5 patients and massive hemoptysis requiring ICU admission in 4. The lifetime prevalence and incidence of hemoptysis secondary to systemic artery reperfusion in HHT patients was estimated to be 1.0% and 0.05%, respectively. Bronchial artery origin was most common (8 patients). In the first patient treated at this center, a major adverse event resulting in myocardial infarct and stroke occurred with the use of 300-500-micron permanent particles. This was presumed to be due to left-to-right shunting and subsequent systemic embolization. Subsequent patients were treated with gelatin sponge slurry without adverse events. This patient ultimately expired due to large volume hemoptysis, in the setting of bilateral diffuse PAVMs. A second patient, with history of childhood bronchial artery coil embolization, expired from large volume hemoptysis while awaiting lobectomy. In two cases, patients underwent surgery, including one lobectomy and one pneumonectomy, for recurrent hemoptysis (requiring at least five hospital admissions). The remaining five patients achieved prolonged resolution of hemoptysis with endovascular treatment alone. CONCLUSION: Lifetime prevalence of hemoptysis secondary to PAVM post-embolization systemic collaterals is rare, but recurrence is high. In this limited series, embolization with gelatin sponge slurry appeared safe, although surgical resection may ultimately be required in refractory and multifocal disease.

Cryoablation of Venous Malformations: A Systematic Review.

This study aimed to review systematically the efficacy, safety, and technical aspects of cryoablation in the treatment of venous malformations (VMs) and to provide the groundwork for future studies. A literature search for clinical studies utilizing percutaneous cryoablation of VMs was performed. All clinical studies related to primary or secondary treatment of VMs with percutaneous cryoablation were included in this review. These selected studies were evaluated for patient characteristics, cryoablation technique, technical success, lesion size and pain scores before and after cryoablation, and adverse outcomes. Random effects analysis of postprocedural changes in lesion volume and pain scores was performed. There were 54 patients with 55 cases of cryoablation of VMs. Of these cases, 27 recorded changes in lesion volume and 31 recorded changes in pain scores. The weighted mean postprocedural decrease in lesion size was 92.0% (raw average, 71.7%). The weighted mean reduction in pain score was 77% (raw average, 78.2%). Considering all treated cases (55), complete resolution of symptoms was seen in 35 cases (63.6%) and overall (complete or partial) improvement in 52 cases (94.5%). Common postprocedural symptoms included pain, bruising, swelling and numbness lasting less than 2 weeks. There were two major adverse events (3.7%), with both cases due to persistent dysesthesia. Patients with a history of prior sclerotherapy demonstrated lower preprocedural and postprocedural pain scores (4.7 and 1.3) than patients without prior treatments (5.8 and 2.8). Cryoablation of VMs appears to be potentially safe and effective on limited short-interval follow-up.

Incidence of Spontaneous Pulmonary AVM Rupture in HHT Patients.

The spontaneous rupture of pulmonary AVMs, resulting in pulmonary hemorrhage and hydrothorax, is a life-threatening complication. While this phenomenon has been previously reported, the true incidence is not yet known. This study retrospectively reviewed records of 801 HHT patients with pulmonary AVMs to identify a single lifetime episode of hemothorax or pulmonary hemorrhage secondary to pulmonary AVM rupture. The lifetime prevalence and incidence of pulmonary AVM rupture in HHT patients was 2.7% and 0.16% respectively. In these patients, AVM rupture represented the initial presentation of HHT in nine (40.9%) cases and was life-threatening in nine (40.9%) cases. All cases occurred in virgin lesions, and subsequent embolization was curative. While a feared complication, pulmonary AVM rupture is rare and is likely effectively prevented by existing embolization techniques and indications.