Bjarnason, Haraldur

Background Patients with peripheral artery disease are at increased risk for major adverse cardiac events, major adverse limb events, and all‐cause death. Developing tools capable of identifying those patients with peripheral artery disease at greatest risk for major adverse events is the first step for outcome prevention. This study aimed to determine whether computer‐assisted analysis of a resting Doppler waveform using deep neural networks can accurately identify patients with peripheral artery disease at greatest risk for adverse outcome events. Methods and Results Consecutive patients (April 1, 2015, to December 31, 2020) undergoing ankle–brachial index testing were included. Patients were randomly allocated to training, validation, and testing subsets (60%/20%/20%). Deep neural networks were trained on resting posterior tibial arterial Doppler waveforms to predict major adverse cardiac events, major adverse limb events, and all‐cause death at 5 years. Patients were then analyzed in groups based on the quartiles of each prediction score in the training set. Among 11 384 total patients, 10 437 patients met study inclusion criteria (mean age, 65.8±14.8 years; 40.6% women). The test subset included 2084 patients. During 5 years of follow‐up, there were 447 deaths, 585 major adverse cardiac events, and 161 MALE events. After adjusting for age, sex, and Charlson comorbidity index, deep neural network analysis of the posterior tibial artery waveform provided independent prediction of death (hazard ratio [HR], 2.44 [95% CI, 1.78–3.34]), major adverse cardiac events (HR, 1.97 [95% CI, 1.49–2.61]), and major adverse limb events (HR, 11.03 [95% CI, 5.43–22.39]) at 5 years. Conclusions An artificial intelligence–enabled analysis of Doppler arterial waveforms enables identification of major adverse outcomes among patients with peripheral artery disease, which may promote early adoption and adherence of risk factor modification.

Background: Percutaneous image-guided thermal ablation has emerged as a treatment option for vascular malformations (VM). However, prospective data on intermediate to long-term effectiveness with uniform follow-up are lacking. Purpose: To prospectively evaluate the 12-month pain severity and pain interference outcomes following percutaneous MRI-guided laser ablation and cryoablation of focal painful, peripheral soft tissue VM. Materials and Methods: Participants undergoing clinically indicated MRI-guided laser ablation and cryoablation for focal painful (worst pain ≥4 out of 10 on Visual Analog Scale), peripheral soft tissue vascular malformations (VM) were enrolled in an IRB-approved prospective, observational study after giving informed consent. Participants completed the Brief Pain Inventory questionnaire prior to ablation and 1, 3, 6, and 12-month postablation. Differences in pain severity and interference outcomes from baseline on a 0 to 10 scale were compared using a paired t-test. Results: Seventeen participants (15 female; mean age 28.3 ± 9.3 years) underwent 24 MRI-guided and monitored ablation sessions including laser (n = 21), cryoablation (n = 2), or both (n = 1) for treatment of painful slow-flow (n = 16) or high-flow (n = 1) VM. Median maximal VM diameter was 5.7 cm (range 1.1 to 31.0 cm). Mean (±SD) preablation worst pain score was 7.9 ± 1.4. There was a significant decrease in worst pain at 1-month postablation (–3.5 ± 2.9; P = .0007) that was sustained at 3 (–3.4 ± 3.2; P = .0007), 6 (–4.2 ± 3.6; P = .0003), and 12 months (–3.6 ± 3.9; P = .002), with similar results for average, current, and least pain scores. There was a significant improvement in pain interference outcomes at 12-month postablation: general activity (P = .018), walking ability (P = .008), work (P = .003), sleep (P = .007), and enjoyment of life (P = .033). Conclusions: These data suggest that MRI-guided and monitored thermal ablation is safe and provides early and sustained significant improvements in pain severity and pain interference outcomes during the first year of follow-up in participants with focal painful peripheral soft tissue VM.

Background: Patients with peripheral artery disease (PAD) are at increased risk for major adverse limb and cardiac events including mortality. Developing screening tools capable of accurate PAD identification is a necessary first step for strategies of adverse outcome prevention. This study aimed to determine whether machine analysis of a resting Doppler waveform using deep neural networks can accurately identify patients with PAD. Methods: Consecutive patients (4/8/2015 – 12/31/2020) undergoing rest and postexercise ankle–brachial index (ABI) testing were included. Patients were randomly allocated to training, validation, and testing subsets (70%/15%/15%). Deep neural networks were trained on resting posterior tibial arterial Doppler waveforms to predict normal (> 0.9) or PAD (⩽ 0.9) using rest and postexercise ABI. A separate dataset of 151 patients who underwent testing during a period after the model had been created and validated (1/1/2021 – 3/31/2021) was used for secondary validation. Area under the receiver operating characteristic curves (AUC) were constructed to evaluate test performance. Results: Among 11,748 total patients, 3432 patients met study criteria: 1941 with PAD (mean age 69 ± 12 years) and 1491 without PAD (64 ± 14 years). The predictive model with highest performance identified PAD with an AUC 0.94 (CI = 0.92–0.96), sensitivity 0.83, specificity 0.88, accuracy 0.85, and positive predictive value (PPV) 0.90. Results were similar for the validation dataset: AUC 0.94 (CI = 0.91–0.98), sensitivity 0.91, specificity 0.85, accuracy 0.89, and PPV 0.89 (postexercise ABI comparison). Conclusion: An artificial intelligence-enabled analysis of a resting Doppler arterial waveform permits identification of PAD at a clinically relevant performance level.

Rationale: The role of cardiac natriuretic peptides (NPs) in peripheral arterial disease (PAD) or thromboangiitis obliterans (TA) is unknown. Recent studies in mice suggested that BNP may be produced outside the heart in the ischemic limbs contributing to peripheral angiogenesis. Objective: Determine if synthesis or consumption/degradation of NPs occur in the ischemic legs of patients with PAD or TA. Methods: 32 patients with critical limb ischemia (CLI) or claudication (PAD n=31; TA n=1; 20 males; mean age 72.9 years) underwent diagnostic angiography or revascularization. We determined differences of concentrations of BNP, NT-proBNP, and CNP in the blood of proximal veins and arteries of both legs. Concentrations differences were then compared between the more ischemic target and the contralateral self-control legs. Results: Values are means ± SD. P values <0.05 were considered significant. In the PAD group, in the target extremity, concentration step-ups of NT-proBNP (11±68; p=0.40) and CNP (0.45±6.22; p=0.71) were not significant from the arterial to venous blood. In the contralateral self-control legs, NT-proBNP and CNP concentrations drops were also not significant (-37±160, p=0.7; -0.89±4.09, p=0.23). Venous BNP concentrations were significantly lower than arterial both in the target (-66±153, p<0.001) and self-control legs (-59±107, p<0.001). BNP concentrations drops were greater in the CLI than claudication cases driving the overall significance. In the patient with TA, whose only identifiable PAD risk factor was smoking, arterial concentrations of NPs were generally low (NT-proBNP 81; BNP 46; CNP 8.2), but higher than venous concentrations (80; 41; 6.7). Conclusion: Significantly lower venous BNP concentrations suggest possible BNP consumption/degradation in the ischemic legs. Concentrations of NT-proBNP, that has a longer half-life than BNP, were more stable suggesting no significant local production or conversion to BNP. CNP concentrations were stable. Recognizing the angiogenic properties of NPs and lack of evidence of peripheral production, studies are warranted in humans with PAD to determine the potential angiogenic properties of exogenous NPs supplementation in what could be considered a local NPs deficiency state.

Background Prophylactic use of inferior vena cava filters to prevent pulmonary embolism in trauma is controversial. The practice varies between hospitals and countries, in part due to conflicting evidence and guidelines. Purpose To compare the effects of pulmonary embolism, deep venous thrombosis and mortality in two hospitals using prophylactic inferior vena cava filter placement or prophylactic anticoagulation alone. Material and Methods Patients presenting with severe trauma were recruited from two level-1 trauma centres between January 2008 and December 2013. Recruited patients from an US hospital having prophylactic inferior vena cava filter inserted were compared to a Scandinavian hospital using prophylactic anticoagulation alone. Inclusion criteria were age >15 years, Injury Severity Score >15 and survival >24 h after hospital admission. Patients with venous thromboembolism diagnosed prior to inferior vena cava filter placement were excluded. A Cox proportional hazard regression model was used with adjustment for immortal time bias and predictor variables. Results In total, 951 patients were reviewed, 282 from an US hospital having inferior vena cava filters placed and 669 from a Scandinavian hospital without inferior vena cava filters. The mean age was 45.9 vs. 47.4 years and the mean Injury Severity Score was 29.8 vs. 25.9, respectively. Inferior vena cava filter placement was not associated with the hazard of pulmonary embolism (Hazard ratio=0.43; 95% confidence interval (CI) 0.12, 1.45; P=0.17) or mortality (Hazard ratio=1.16; 95% CI 0.70, 1.95; P=0.56). However, an increased rate of deep venous thrombosis was observed with inferior vena cava filters in place (Hazard ratio=3.75; 95% CI 1.68, 8.36; P=0.001). Conclusion In severely injured trauma patients, prophylactic inferior vena cava filter placement was not associated with pulmonary embolism or mortality. However, inferior vena cava filters were associated with increased rate of deep venous thrombosis.

Background To review long-term outcomes and saphenous vein (SV) occlusion rate after endovenous ablation (EVA) for symptomatic varicose veins. Methods A review of our EVA database (1998–2018) with at least 3-years of clinical and sonographic follow-up. The primary end point was SV closure rate. Results 542 limbs were evaluated. 358 limbs had radiofrequency and 323 limbs had laser ablations; 542 great saphenous veins (GSV), 106 small saphenous veins (SSV) and 33 anterior accessory saphenous veins (AASV) were treated. Follow-up was 5.6 ± 2.3 years; 508 (74.6%) veins were occluded, 53 (7.8%) partially occluded and 120 (17.6%) were patent. On multivariable Cox regression analysis, male sex (HR 1.6, 95% CI [0.46–018], p = 0.012) and use anticoagulation (HR 2.0, 95% CI [0.69–0.34], p = 0.044) were predictors of long-term failure. On Kaplan-Meier curve, we had an 86.3% occlusion rate. Conclusion Our experience revealed a 5-year closure rate of 86.3%. Ablations have satisfactory occlusion rate.

The American Venous Forum (AVF) and the Society for Vascular Surgery set forth these guidelines for the management of endothermal heat-induced thrombosis (EHIT). The guidelines serve to compile the body of literature on EHIT and to put forth evidence-based recommendations. The guidelines are divided into the following categories: classification of EHIT, risk factors and prevention, and treatment of EHIT. One major feature is to standardize the reporting under one classification system. The Kabnick and Lawrence classification systems are now combined into the AVF EHIT classification system. The novel classification system affords standardization in reporting but also allows continued combined evaluation with the current body of literature. Recommendations codify the use of duplex ultrasound for the diagnosis of EHIT. Risk factor assessments and methods of prevention including mechanical prophylaxis, chemical prophylaxis, and ablation distance are discussed. Treatment guidelines are tailored to the AVF EHIT class (ie, I, II, III, IV). Reference is made to the use of surveillance, antiplatelet therapy, and anticoagulants as deemed indicated, and the recommendations incorporate the use of the novel direct oral anticoagulants. Last, EHIT management as it relates to the great and small saphenous veins is discussed.

Abstract Introduction May–Thurner syndrome (MTS) is a vascular anatomic variant resulting in compression of the left common iliac vein by the right common iliac artery, affecting approximately 22% of the population. In adults, following acute deep vein thrombosis (DVT) of the iliofemoral veins, the incidence of postthrombotic syndrome (PTS) and recurrent DVT are high if treated with anticoagulation alone, warranting adjunctive treatment with thrombolysis and stent placement. However, there is paucity of literature documenting the course of treatment and associated outcomes in pediatric patients with MTS. Methods A retrospective chart review of pediatric patients (≤ 18 years of age) with radiologic confirmation of MTS with or without DVT evaluated and/or treated at our institution from January 1, 2005 through December 31, 2015 was conducted. Results Seventeen patients (4 male; 13 female) were identified. Median age was 15.4 years (range 8.8–17.1 years) with a median follow-up of 1.2 years (range 0.4–7.5 years). Thirteen (76.5%) patients presented with left lower extremity DVT. Management included catheter-directed thrombolysis (n = 5), systemic thrombolysis (n = 1), and mechanical thrombectomy (n = 1). Fifteen patients were treated with anticoagulation including two patients with endovascular stents without DVT. Median duration of anticoagulation was 6.3 months (range 3.2–18.7 months). Ten patients (59%) underwent stent placements.Complete and partial thrombus resolution was noted in six patients each and no resolution in one patient. Four patients had recurrence/progression of thrombus (n = 3 with stents) at a median time of 29 days (range 12–495 days). No bleeding complications were observed. Clinically documented or self-reported PTS was noted in 8 patients (62%). Conclusion There are no clear guidelines for MTS management in children and adolescents. In our cohort, thrombolysis, anticoagulation, or stent placements were not associated with bleeding risks, with recurrence/progression of DVT and signs and symptoms of PTS noted in 30 and 62%, respectively. Further studies are needed to determine a standardized treatment approach of the pediatric patient with MTS with or without thrombosis.