Abstract Guidelines recommend placement of inferior vena cava filters (IVCFs) in patients with acute proximal lower extremity deep vein thrombosis (DVT) and a contraindication to anticoagulation. IVCF placement during pregnancy or immediately postpartum presents technical challenges and is not extensively described in the existing literature. This study aimed to describe the use of IVCFs in the obstetric population along with outcomes related to filter placement. Retrospective chart review of all patients at Mayo Clinic from 2001 to 2020 with an IVCF at the time of conception or who underwent placement during pregnancy/postpartum. About 24 pregnancies in 23 women (mean age 26.3 years, range 18–41) were included: 5 (21%) with IVCF placement prior to pregnancy, 7 (29%) during pregnancy, and 12 (50%) during postpartum. IVCFs placed during pregnancy were frequently in the suprarenal position, in 5 (71%) cases. Meanwhile, 16 (94%) were deployed in an infrarenal position prior to pregnancy and postpartum. Complications included multiple attempts to remove the IVCF (n = 2), severe angulation (n = 4), embedded struts (n = 3), fracture (n = 1), and one case of cardiac tamponade (n = 1). Complications were more common when placement was performed prior to pregnancy or during pregnancy (2, 40% and 4, 57% respectively) versus postpartum (2, 17%). IVCF placement prior or during pregnancy/postpartum is uncommon and is associated with a high incidence of complications, although most did not fundamentally impact clinical outcomes. While IVCFs remain an option for clinicians treating pregnant and postpartum patients, these should be considered a last resource.
Venous Thromboembolism Outcomes Among Cancer and Non-cancer Patients Managed with Patient-centric Guideline-driven Protocol
Abstract Patients with cancer and venous thromboembolism (VTE) have higher complication rates of anticoagulation. However, studies supporting this data are relatively old reflecting the era of vitamin K inhibitors. To assess VTE recurrence, major bleeding, and clinically relevant non-major bleeding (CRNMB) in patients (March 1, 2013 to April 30, 2023) with cancer-associated VTE and patients without cancer, the prospective Mayo Clinic Thrombophilia Clinic Registry was analyzed. Over the study period, 4,711 patients with acute VTE were enrolled including 2,064 patients with cancer (mean age 62.5 ± 12.4, 46% female) and 2,647 patients without cancer (mean age 59.4 ± 16.0, 45% female). The most common cancers were gastrointestinal (n = 423, 21%), pancreatic (n = 287, 14%), and genitourinary (n = 198, 10%). Direct oral anticoagulants were used in 1,339 (65%) cancer and in 1,952 (74%) non-cancer patients. Among cancer patients, 12-month Kaplan–Meier probability of VTE recurrence was 2.4-fold greater (7.1% vs. 2.9%, p < 0.001) compared with the non-cancer group, including higher recurrent leg deep vein thrombosis (3.0% vs. 1.4%; p = 0.002) and pulmonary embolism (3.5% vs. 1.0%, p < 0.001). Patients with cancer also had 2.1-fold greater risk of major bleeding (6.3% vs. 3.0%; p < 0.001) including bleeding from the gastrointestinal tract (3.0 vs. 1.4, p = 0.01) compared with patients without cancer. Clinically relevant non-major bleeding events were similar between the groups. In this large prospective registry of VTE management, patients with cancer had significantly higher rates of VTE recurrence and major bleeding compared with patients without cancer, yet the rate of complications are substantially smaller relative to historic values of a prior vitamin K antagonist era.
The AI-Mayo PE (AIM PE) Study: Validation of an Artificial Intelligence Algorithm Using Electrocardiograms to Predict Pulmonary Emboli
Background: Risk stratification for suspected pulmonary emboli (PE) remains an area of active research. Current risk stratification algorithms have moderate discriminatory capabilities and are guideline-recommended, but they are poorly utilized in practice, with most clinicians relying predominantly on their clinical training and personal “gestalt.” Our group recently derived an Artificial Intelligence (AI) algorithm using electrocardiograms (ECG) to predict the presence of PE (AUC 0.69) on computed tomography scans of the pulmonary arteries (CTPA) in a cohort of 79K patients. Aim: Validate the AI-ECG algorithm in a contemporary dataset of patients with suspected PE. Methods: Emergency Department (ED) visits between 9/1/2022 and 12/31/2023 across the Mayo Clinic Enterprise were searched using a unified data platform. ED visits in patients over 18 years of age with a discretely documented Wells' PE or PERC Rule, a D-dimer result, or a CTPA were included. Only CTPA imaging and D-dimers performed within 48 hours of ED admission were eligible to be included. Patients were included in the final cohort if an ECG was performed within 6 hours of ED admission, D-dimer testing, or CTPA. Patients were considered negative for PE if CTPA was negative, and when this wasn't performed, a negative D-dimer (high sensitivity) or PERC rule of 0 was considered negative. A previously derived Artificial Neural Network algorithm to analyze the ECG to predict PE was applied to the dataset for validation. Results: A total of 27,028 ED visits in 24,288 unique patients meet inclusion criteria. Among this group, the first ED visit with a CTPA and an ECG within 6 hours was included, leaving 18,936 patients for the final validation cohort. The mean age of the cohort was 54.7 (SD 18.7), and 57% were male. Among the entire cohort, 13,573 underwent D-dimer testing for which 4,895 (36%) were positive at standard thresholds. A total of 10,486 patients underwent CTPA (55% of patients evaluated), of which 455 were positive for PE (4.3%). Using the AI-ECG model from the derivation cohort applied to this validation cohort resulted in an AUC of 0.69, identical to the derivation cohort. Using ECG model estimates alone, low (0.74%, n=2447, NPV 99.3%), elevated (2.27%, n=15404, NPV, 97.72%), and high-risk (8.02%, n=1085, NPV 91.98%) categories for PE can be created. A negative D-dimer in the elevated risk group increased the negative predictive value (NPV) to >99.9% and could be used to reduce imaging in this group further. Using the proposed ECG to D-dimer cascade risk stratification could further reduce the need for PE imaging for an overall NPV of 99.9% and sensitivity of 95.2%. We then used additional clinical parameters to train a new algorithm with additional clinical data and the AI-ECG algorithm estimates. Multiple machine learning algorithms were then evaluated in a dataset divided into training (2/3) and testing (1/3) datasets, after downsampling (to address class imbalance). The best results were obtained with AI-ECG results and D-dimer: Ada Boost (AUC 0.93, F1 score 0.895) compared to standard logistic regression (AUC 0.79, F1 score 0.746). The addition of age, sex, and oxygen saturation did not improve model performance. Conclusion: We have now validated the previously derived AI-ANN ECG algorithm for PE in a contemporary and independent cohort and demonstrate potential for integration into clinical PE assessment algorithms. Unlike prior risk stratification processes, ECGs are invariably performed in patients with cardiopulmonary symptoms and have the potential to prevent missed or delayed PE diagnosis by proactively identifying high-risk patients. Additionally, we demonstrate that the results of this algorithm can be combined with D-dimer values, resulting in a simple, powerful, predictive algorithm (AUC 0.93) that pairs cardiovascular electrophysiology with laboratory biomarkers and could lead to a new paradigm in clinical risk stratification for PE.
Echocardiographic findings in cancer-associated non-bacterial thrombotic endocarditis: clinical series of 111 patients from a single institution
Abstract Aims Echocardiographic assessment of cancer-associated non-bacterial thrombotic endocarditis (Ca-NBTE) is limited to case reports and small clinical series. The study aimed to identify heart valve abnormalities and its relation to embolic complications and cancer types. Methods and results Manual review of echocardiographic images and medical records of Mayo Clinic patients (31 March 2002–30 June 2022) was performed. Ca-NBTE in 111 patients (mean age 63.2 ± 9.7 years, 66.7% female) predominantly affected mitral valves (MV) (69), 56 aortic (AV), 8 tricuspid (TV), and rarely pulmonic (PV) (1). In 18 patients, 2 valves were involved, 3 and 4 valve involvement in only a single patient each. Embolic complications were prevalent (n = 102, 91.9%). Ca-NBTE affected MV more frequently on the upstream (atrial) (90% vs. 49.3%) and TV downstream (ventricular) side (75% vs. 37.5%). NBTE size (cm) varied significantly among valves, with TV hosting the largest masses (0.63–2.40 × 0.39–1.77), compared with MV [(0.11–1.81 × 0.11–1.62), (length P = 0.001; width P = 0.03)] and AV [(0.20–2.70 × 0.11–1.51), (length P = 0.001; width P = 0.056)]; MV masses were borderline longer in systemic compared with cerebral emboli (P = 0.057). Majority of MV (79.6%) and AV (69.6%) had thickened leaflets. NBTE lesions commonly affected closing margins (73.9% MV, 85.7% AV, and 62.5% of TV) but rarely commissures of MV (8.7%), yet fairly frequently of AV (41.1%). Five patients had severe regurgitation of MV and 5 AV. Conclusion Ca-NBTE manifests mainly as thrombotic mobile masses attached to thickened MV and AV, with distinct variations in size based on valve type. Embolic destination but not cancer type is associated with NBTE mass size and location.
Aim. Thromboembolic presentation (stroke, mesenteric or limb ischemia) in non-valvular atrial fibrillation may occur randomly or may identify unique subpopulations of patients with this dysrhythmia. The aim of this study was to determine whether future major adverse cardiovascular event rates (myocardial infarction, stroke, peripheral arterial embolism, death) differ between patients with peripheral embolism (AFPE) compared to those suffering stroke (AFS). Methods. An inception cohort (1995–2005) with AFPE (n=216) were compared to randomly selected AFS patients (n=241). Results. Patients with AFPE were older than AFS patients (79±10 vs 73±13 years; p<0.001) with a greater percentage of women (71% vs 45%; p<0.001). The most common presentation of AFPE patients was limb ischemia (90%). Except for prior stroke, all CHADS-2 variables were more prevalent in AFPE (Table ). During 3.3±3.6 years of follow up, survival was lower in AFPE compared to either AFS (p<0.001) or age/gender matched controls (p<0.001; Figure ). AFPE patients had lower survival free from recurrent embolization compared to AFS (82% vs 100%; p=0.005). Recurrence free survival for MI and stroke were similar. Conclusions. Patients with peripheral embolization represent a unique subset of non-valvular atrial fibrillation with an increased risk of recurrence and high mortality rates compared to those suffering stroke. Comparison of clinical and echocardiographic characteristics
Abstract 5126: Platelet Specific Factor XIII Gene Expression and Embolic Propensity in Atrial Fibrillation
Background and Aim: Cardioembolic stroke from non-valvular atrial fibrillation (NVAF) begins with the development of left atrial appendage thrombus (LAAT). Although nearly 15% of patients with NVAF have LAAT by transesophageal echocardiography, the annual stroke rate is 5% on average. The overall aim of this project is to identify variables associated with embolic propensity of LAAT. Materials and Methods: LAAT specimens were obtained during cardiac surgery (MAZE procedure; n=26). Embolized thrombi (n=51) were obtained during surgical embolectomy from lower (n=36) and upper extremities (n=11) and mesenteric arteries (n=4). Platelet-rich regions within sectioned thrombi were sampled by punch biopsy from which total RNA was extracted and analyzed for expression of 5 platelet specific genes: A1 domain of factor XIII, (F13A1); integrin α 2b β 3 (ITGA2B); glycoprotein IX (GP9), platelet factor 4 (PF4), glycoprotein Ib (GP1BB). Gene expression was quantified using TaqMan MGB-probe based quantitative real-time polymerase chain reaction normalized to β 2 macroglobulin using cDNAs reverse transcribed from total RNA. Results: Factor XIII gene expression (Figure ) was significantly lower in embolic (mean fold change 0.08) compared to left atrial thrombi in situ (mean fold change 0.28; p=0.03). Expression of other genes did not show significant change by embolic status. Conclusions: Variable Factor XIII gene expression in thrombi generated during NVAF may in part explain the propensity to embolization. Whereas Factor XIII stabilizes thrombi by crosslinking fibrin without influencing atrial attachment, this data suggests that embolization occurs through fragmentation.
Cancer‐associated non‐bacterial thrombotic endocarditis—Clinical series from a single institution
Abstract Premortem clinical presentation of cancer‐associated non‐bacterial thrombotic endocarditis (Ca‐NBTE), therapy, and the clinal course is limited to case reports and small clinical series. An electronic search of Mayo Clinic records (03/31/2002–06/30/2022) with a subsequent manual review was performed to identify adult patients with echocardiographically detected NBTE and active malignancy, excluding those with infectious endocarditis or lupus anticoagulant/antiphospholipid antibodies. In this retrospective cohort study, we analyzed 115 Ca‐NBTE patients (mean age 63.2 ± 9.7 years, 66.1% female) involving 71 (61.7%) mitral, 58 (50.4%) aortic, 8 (6.9%) tricuspid, and 1 (0.9%) pulmonary valve. The most common cancer was lung ( n = 45 cases (39.1%), followed by pancreatic ( n = 19, 16.5%), gynecological (17, 14.8%), gastrointestinal ( n = 10, 8.7%), and 10 (8.7%) with hematologic malignancy; 6 patients had two active cancers. Embolic complications at presentation were frequent: 94 (81.7%) brain, 11 splenic, 10 renal, 6 coronary, and 4 to the extremities. Of 104 anticoagulated patients, 60 received low molecular weight heparin, 17 unfractionated heparin, 16 apixaban, 8 warfarin, and 3 rivaroxaban. There were 18 arterial thromboembolisms; the Kaplan–Meier estimates of the incidence at 2 years were consistent with a rate of 15.9% [95% Confidence Interval (CI) 9.9–23.3], including 14 strokes (12.4%, 95%CI, 7.1–19.2), and 8 other arterial emboli (10.5%, 95%CI, 4.7–18.9); there were 10 venous thromboembolisms (8.9%, 95%CI, 4.5–15.0). Fourteen major bleedings occurred (12.8%, 95%CI, 7.3–19.9) and 94 patients died during follow‐up (77.9%, 95%CI, 71.1–85.8). Ca‐NBTE predominantly affected women with lung adenocarcinoma or digestive tract cancers and manifested by stroke with high mortality and frequent embolic and bleeding complications during anticoagulation therapy.
Artificial Intelligence of Arterial Doppler Waveforms to Predict Major Adverse Outcomes Among Patients Evaluated for Peripheral Artery Disease
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.
Abstract 18878: Right Heart Valves Affected by Cancer-Related Non-Bacterial Thrombotic Endocarditis as Potential Cause of Pulmonary Embolism
Background: Ca-NBTE primarily affects the mitral valve (MV) and aortic valve (AV), with rare involvement of the right heart valves. Premortem descriptions of this condition are limited to a few case reports. This study presents an initial clinical series focusing on patients with Ca-NBTE specifically affecting their right heart valves. We describe the underlying cancers, types of valve lesions, and associated embolic complications. Patients and Methods: A electronic search of medical records (March 31, 2002, to June 30, 2022) was followed by a manual review to identify adult patients with echocardiographically detected NBTE, active cancer, and no infectious endocarditis or lupus anticoagulant/antiphospholipid antibodies. Results: Out of 115 identified patients with Ca-NBTE (mean age 63.2±9.7 years, 66.1% female), there were 8 cases (7.0%) affecting right heart valves (mean age 64.5±12.1 years, 3 females) with underlying cancer: pancreatic (n=3), lung (n= 2), genitourinary (n=1), gastric (n=1) and neck sarcomatoid carcinoma (n=1). TV was affected in 8 patients and PV in one case; 4 patients had Ca-NBTE limited only to PV, 2 patients had MV and TV, 1 patient had mitral, aortic and TV, and 1 patient with pancreatic cancer had all four valves affected by NBTE. 5 patients had embolic complications to the brain with one patient in that group also experiencing emboli to the kidney and spleen. Out of 4 patients with NBTE limited to TV, two still had brain emboli, one had only pulmonary embolism, and one patient had no embolic complications. Conclusion: Around 7% of Ca-NBTE cases involve the right heart valves, with half of these cases limited to the TV. The cancer profile in these cases resembles that seen in left heart valve involvement.
Abstract 14536: Pulmonary Vein Thrombosis: Illuminating the Risk Factors and Sequelae of a Rare and Often Incidentally Diagnosed Pathology
Introduction: Pulmonary vein thrombosis (PVT) is often diagnosed incidentally but data on its management and outcomes are sparse. Methods: We queried our institutional health record to identify patients ≥18 years of age diagnosed with PVT. Demographics, medications, risk factors, diagnostics, treatment, and sequelae were collected by manual chart review. Suspected tumor thrombus cases were excluded. Results: Seventy-two patients with PVT were identified (median age 62 years, 50% male). The cohort was mostly white (85%), overweight (BMI 26 kg/m), with frequent comorbidities including hypertension (44%), hyperlipidemia (38%), atrial fibrillation/flutter (29%), and history of venous thromboembolism (21%). The most common PVT risk factors were active malignancy (54%), lobectomy (21%), surgery within 30 days (19%), and extrinsic vein compression (15%). Most PVT were diagnosed by CT (86%) and affected a single vein (86%), mostly commonly the left upper PV (32%). Laboratory studies revealed median platelet count 243 х 10 9 cells/L (n=58) and D-dimer elevated in 6 patients when measured (67%, n=9). About one-third of patients were on therapeutic anticoagulation (37%) at PVT diagnosis. Most patients were started on new anticoagulation (78%, n=56), with unfractionated heparin as the most common initial therapy (68%). Of those anticoagulated, few were treated with a limited duration (20%, n=11, median 54 d, IQR 95) while most received indefinite anticoagulation (80%, n=45), primarily warfarin (45%), apixaban (24%), or enoxaparin (21%). Serial imaging was obtained in 69% (n=50, median 65 d, IQR 116) and demonstrated resolution of PVT in 32 (64%) patients. Common PVT complications noted were as follows: 4 year risk of LA thrombus (26%, 12/16 anticoagulated), mechanical ventilation (13%), pneumonia (9%), and ischemic stroke (9%, 5/6 anticoagulated). Conclusions: PVT is often associated with active malignancy, lobectomy, recent surgery, and extrinsic vein compression. Most PVT resolve on serial imaging. Clinicians should be aware of potential high-risk sequelae including LA thrombus and stroke as well as high anticoagulation failure rates when managing PVT.