Faculty Bibliography

OBJECTIVE:The development of an accurate, non-invasive method for the diagnosis of peripheral artery disease (PAD) from accelerometer contact microphone (ACM) recordings of the cardiac system. METHODS:Mel frequency cepstral coefficients (MFCCs) are initially extracted from ACM recordings. The extracted MFCCs are then used to fine-tune a pre-trained ResNet50 network whose middle layers provide streams of high-level-of-abstraction coefficients (HLACs) which could provide information on blood pressure backflow caused by arterial obstructions in PAD patients. A vision transformer is finally integrated with the feature extraction layer to detect PAD, and stratify the severity level. This architecture is coined multi-stream-powered vision transformer (MSPViT). The performance of MSPViT is evaluated on 74 PAD and 21 healthy subjects. RESULTS:Sensitivity, specificity, F1 score, and area under the curve (AUC) of 99.45%, 98.21%, 99.37%, and 0.99, respectively, are reported for the binary classification which ensures accurate detection of PAD. Furthermore, MSPViT suggests average sensitivity, specificity, F1 score, and AUC of 96.66%, 97.34%, 96.29%, and 0.96, respectively, for the classification of subjects into healthy, mild-PAD, and severe-PAD classes. The silhouette score is calculated to assess the separability of clusters formed for classes in the penultimate layer of MSPViT. An average silhouette score of 0.66 and 0.81 demonstrate excellent cluster separability in PAD detection and severity classification, respectively. CONCLUSION/CONCLUSIONS:The achieved performance suggests that the proximal ACM-driven framework can replace state-of-the-art techniques for PAD detection. SIGNIFICANCE/CONCLUSIONS:This study presents a fundamental step towards prompt and accurate diagnosis of PAD and stratification of its severity level.

PURPOSE/OBJECTIVE:To investigate the clinical implication of additional below-the-ankle (BTA) intervention in patients with chronic limb-threatening ischemia (CLTI) undergoing below-the-knee (BTK) intervention. MATERIALS AND METHODS/METHODS:.gov identifier NCT01855412), a prospective, observational, core-laboratory adjudicated, multicenter study of endovascular intervention in 1204 patients. Patients with CLTI (Rutherford Classification 4-6) who underwent BTK intervention were included in this sub-analysis. Participants were then stratified into 2 treatment groups according to whether at least one lesion intervened on was BTA (n=66) or not (n=273). The decision on whether and where to intervene was made during the procedure. The main outcome measures included major amputation, target vessel revascularization (TVR), major adverse events (MAE), survival, amputation-free survival, major adverse limb events or peri-operative death (MALE-POD), and all-cause death. Other outcome measures included procedural success, procedural complications, and wound healing rate. RESULTS:There were no differences in procedural success or severe angiographic complications between the 2 groups. At 1-year post-procedure, patients in the BTK group had a higher rate of freedom from major amputation (95.0% vs. 86.9%, respectively; HR: 2.87, 95% CI: 1.17-7.03), a higher rate of freedom from TVR (80.1% vs. 66.9%, respectively; HR: 1.94, 95% CI: 1.14-3.32), a higher rate of freedom from MALE-POD (94.6% vs. 86.9%, respectively; HR: 2.65, 95% CI: 1.10-6.41), and a higher rate of freedom from MAE at both 1 (76.0% vs. 60.1%, respectively; HR: 2.00, 95% CI: 1.24-3.22) and 3 years post procedure (67.5% vs. 55.8%, respectively; HR: 1.69, 95% CI: 1.08-2.65). There was a significantly lower rate of survival in the BTK group at 3 years (74.3% vs. 91.1%, respectively; HR: 0.35, 95% CI: 0.14-0.87). After risk adjustment, there was a higher rate of all-cause death in the BTK group at 3 years (19.4% vs. 9.1%, respectively; p=0.023) post-intervention. CONCLUSION/CONCLUSIONS:Patients with disease requiring intervention to BTA lesions have a potential increased amputation rate in the short term, but BTA intervention carries a potential survival benefit in the long term when compared to BTK intervention alone.

BACKGROUND/PURPOSE:The transradial approach has been proposed as an alternative to traditional transfemoral access for diagnostic and therapeutic purposes in several catheterization procedures. Historically, extended length devices for lower limb endovascular interventions have been limited. The aim of this study was to investigate the acute clinical outcomes of orbital atherectomy (OA) via transradial access (TRA) for the treatment of lower extremity peripheral artery disease (PAD). METHODS/MATERIALS:REACH PVI was a multicenter, prospective, observational study (NCT03943160) including subjects with PAD and target lesion morphology appropriate for OA. All patients were followed post-procedure through the first standard of care follow-up visit. RESULTS:A total of 50 patients were enrolled. In most cases the indication for intervention was disabling claudication (74.0%). Overall, 50 target lesions were treated, 92.0% of lesions were femoropopliteal and 8.0% were infrapopliteal. The average lesion length was 98.3 ± 87.5 mm and 78.0% of the lesions were severely calcified. Balloon angioplasty was performed in 98.0% of target lesions, while a stent was deployed in 16.0%. Treatment success was 98.0%; in only one case the result was sub-optimal (>30% stenosis with stent placement) and a significant dissection was reported. No serious distal embolization, serious thrombus formation or serious acute vessel closure were observed intra- or post-procedurally. CONCLUSIONS:Transradial OA followed by percutaneous transluminal angioplasty for lower extremity PAD is feasible and demonstrates a favorable safety profile. Extended length devices such as the Extended Length Orbital Atherectomy System could further facilitate transradial endovascular procedures by increasing its spectrum of application.

Recent research has shown promising results for the detection of aortic stenosis (AS) using cardio-mechanical signals. However, they are limited by two main factors: lacking physical explanations for decision-making on the existence of AS, and the need for auxiliary signals. The main goal of this paper is to address these shortcomings through a wearable inertial measurement unit (IMU), where the physical causes of AS are determined from IMU readings. To this end, we develop a framework based on seismo-cardiogram (SCG) and gyro-cardiogram (GCG) morphologies, where highly-optimized algorithms are designed to extract features deemed potentially relevant to AS. Extracted features are then analyzed through machine learning techniques for AS diagnosis. It is demonstrated that AS could be detected with 95.49-100.00% confidence. Based on the ablation study on the feature space, the GCG time-domain feature space holds higher consistency, i.e., 95.19-100.00%, with the presence of AS than HRV parameters with a low contribution of 66.00-80.00%. Furthermore, the robustness of the proposed method is evaluated by conducting analyses on the classification of the AS severity level. These analyses are resulted in a high confidence of 92.29%, demonstrating the reliability of the proposed framework. Additionally, game theory-based approaches are employed to rank the top features, among which GCG time-domain features are found to be highly consistent with both the occurrence and severity level of AS. The proposed framework contributes to reliable, low-cost wearable cardiac monitoring due to accurate performance and usage of solitary inertial sensors.

This study presents our recent findings on the classification of mean pressure gradient using angular chest movements in aortic stenosis (AS) patients. Currently, the severity of aortic stenosis is measured using ultra-sound echocardiography, which is an expensive technology. The proposed framework motivates the use of low-cost wearable sensors, and is based on feature extraction from gyroscopic readings. The feature space consists of the cardiac timing intervals as well as heart rate variability (HRV) parameters to determine the severity of disease. State-of-the-art machine learning (ML) methods are employed to classify the severity levels into mild, moderate, and severe. The best performance is achieved by the Light Gradient-Boosted Machine (Light GBM) with an F1-score of 94.29% and an accuracy of 94.44%. Additionally, game theory-based analyses are employed to examine the top features along with their average impacts on the severity level. It is demonstrated that the isovolumetric contraction time (IVCT) and isovolumetric relaxation time (IVRT) are the most representative features for AS severity.Clinical Relevance- The proposed framework could be an appropriate low-cost alternative to ultra-sound echocardiography, which is a costly method.

We aimed to investigate the relationship of modified body mass index (mBMI), the product of BMI and serum albumin, with survival after transcatheter (TAVI) and surgical aortic valve implantation (SAVI). Frailty is associated with poor outcomes after TAVI and SAVI for severe aortic stenosis (AS). However, clinical frailty is not routinely measured in clinical practice due to the cumbersome nature of its assessment. Modified BMI is an easily measurable surrogate for clinical frailty that is associated with survival in elderly cohorts with non-valvular heart disease. We utilized individual patient-level data from a pooled database of the Placement of Aortic Transcatheter Valves (PARTNER) trials from the PARNTER1, PARTNER2 and S3 cohorts. We estimated cumulative mortality at 1 year for quartiles of mBMI with the Kaplan-Meier method and compared them with the log-rank test. We performed Cox proportional hazards modeling to assess the association of mBMI strata with 1-year mortality adjusting for baseline clinical characteristics. A total of 6593 patients who underwent TAVI or SAVI (mean age 83±7.3 years, 57% male) were included. mBMI was independently associated with all-cause one-year mortality with the lowest mBMI quartile as most predictive (HR 2.33, 95% CI 1.80-3.02, p < 0.0001). Notably, mBMI performed as well as clinical frailty index to predict 1-year mortality in this cohort. In conclusion, modified BMI predicts 1-year survival after both TAVI and SAVI. Given that it performed similar to the clinical frailty index, it may be used as a clinical tool for assessment of frailty prior to valve implantation.

Coronavirus disease 2019 (COVID-19) may predispose patients to venous thromboembolism (VTE). Limited data are available on the utilization of the Pulmonary Embolism Response Team (PERT) in the setting of the COVID-19 global pandemic. We performed a single-center study to evaluate treatment, mortality, and bleeding outcomes in patients who received PERT consultations in March and April 2020, compared to historical controls from the same period in 2019. Clinical data were abstracted from the electronic medical record. The primary study endpoints were inpatient mortality and GUSTO moderate-to-severe bleeding. The frequency of PERT utilization was nearly threefold higher during March and April 2020 (n = 74) compared to the same period in 2019 (n = 26). During the COVID-19 pandemic, there was significantly less PERT-guided invasive treatment (5.5% vs 23.1%, p = 0.02) with a numerical but not statistically significant trend toward an increase in the use of systemic fibrinolytic therapy (13.5% vs 3.9%, p = 0.3). There were nonsignificant trends toward higher in-hospital mortality or moderate-to-severe bleeding in patients receiving PERT consultations during the COVID-19 period compared to historical controls (mortality 14.9% vs 3.9%, p = 0.18 and moderate-to-severe bleeding 35.1% vs 19.2%, p = 0.13). In conclusion, PERT utilization was nearly threefold higher during the COVID-19 pandemic than during the historical control period. Among patients evaluated by PERT, in-hospital mortality or moderate-to-severe bleeding were not significantly different, despite being numerically higher, while invasive therapy was utilized less frequently during the COVID-19 pandemic.

BACKGROUND:Transpedal access is increasingly utilized for the treatment of peripheral artery disease (PAD). Femoral-popliteal artery chronic total occlusions (CTOs) are some of the most difficult lesion subsets that sometimes require the use of re-entry support devices during percutaneous intervention. Limited data is available on the use of re-entry devices when treating femoral-popliteal CTOs via transpedal access. The aim of this study was to demonstrate the feasibility of using the Outback® Elite re-entry device for the treatment of femoral-popliteal CTOs via the transpedal approach in an outpatient based lab setting. METHODS:Seventeen patients presented with femoral-popliteal CTOs in which treatment required the use of the Outback® Elite re-entry device. All procedures were performed in a single outpatient based lab. Patients were followed at 1 week and 1 month post-procedure, with lower extremity arterial duplex ultrasound assessment during the 1 month follow-up. RESULTS:The average patient age was 78 years-old, with 71% being males. Most patients presented with Rutherford class IV symptoms. Procedural success was achieved in all patients with no requirement to convert to femoral artery access in any of the cases. No immediate post-procedural complications nor at any time during follow-up were observed. Ultrasonography at 1 month follow-up showed patent intervention sites and access site vessels in all patients. CONCLUSION/CONCLUSIONS:The use of the Outback® Elite re-entry device for the treatment of femoral-popliteal CTOs via transpedal access is a feasible option and may have potential benefits by avoiding risks associated with traditional femoral artery access.

BACKGROUND:While slow gait speed is known to be associated with poor outcomes in patients at high surgical risk who undergo transcatheter aortic valve replacement (TAVR), the prognostic significance of slow gait speed in intermediate risk TAVR patients is poorly understood. OBJECTIVES:We assessed the association between baseline 6-min walk test (6MWT) performance and both 2-year mortality and health status in intermediate risk patients undergoing TAVR as a part of the PARTNER II/S3i studies. METHODS:The association of baseline 6MWT with mortality over 2-years after TAVR was examined using Cox regression; both unadjusted and adjusted for age, left ventricular ejection fraction, coronary artery disease, pulmonary disease, renal insufficiency, and STS score. Patients were divided into four groups according to baseline 6MWT: unable to walk and in three equal tertiles of slow, medium, and fast walkers. Among surviving patients, improvement in 6MWT and quality of life were compared. RESULTS:Among 2,037 intermediate risk TAVR patients (mean age 81.7 years, STS score 5.6%), 8.2% were unable to walk. Baseline 6MWT was associated with all-cause mortality over 2 years (Hazard ratio (HR) 0.87 per 50 m, 95% confidence interval [CI] 0.83 to 0.92, p < .0001). Among surviving patients, the adjusted absolute change in 6MWT at 2 years improved for patients unable to walk (+134.1 m, 95% CI 102.1 to 166 m, p < .0001) and slow walkers (+60.5 m, 95% CI 42.8 to 78.2 m, p < .0001), but was unchanged for medium walkers (-7.3 m, 95% CI -24.3 to 9.6 m, p = .4), and declined for fast walkers (-41.3 m, 95% CI -58.7 to -23.9 m, p < .0001). CONCLUSION:Poor functional capacity is predictive of 2-year mortality in elderly intermediate risk patients undergoing TAVR. However, surviving patients with poor baseline functional capacity had significant improvement in 6MWT performance and quality of life at 2-years following TAVR.

BACKGROUND:Oldest-old patients (≥85 years) constitute half the acute myocardial infarction hospitalizations among older adults and more commonly have atypical presentation, under-treatment and functional impairments. Yet this group has not been well characterized. OBJECTIVES/OBJECTIVE:We characterized differences in presentation, functional impairments, treatments, health status, and mortality among middle-old (75-84 years) and oldest-old patients with myocardial infarction. METHODS:We analyzed data from the ComprehenSIVe Evaluation of Risk Factors in Older Patients with AMI (SILVER-AMI) study that enrolled 3041 patients ≥75 years of age from 94 hospitals across the US between 2013-2016. We performed Cox proportional hazards regression to examine the association between the oldest-old (n=831) and middle-old (n=2210) age categories with post-discharge 6-month case fatality rate adjusting for socio-demographic and clinical variables, and mobility impairment. RESULTS:The oldest-old were less likely to present with chest pain (52.7% vs. 57.7%) as their primary symptom or to receive coronary revascularization (58.1% vs. 71.8) (p<0.01 for both). The oldest-old were more likely to have functional impairments and had higher 6-month mortality compared with the middle-old patients (HR 1.78, 95% CI 1.39-2.28). This association was substantially attenuated after adjusting for mobility impairment (HR 1.29, 95% CI 0.99-1.68). CONCLUSIONS:There is considerable heterogeneity in presentation, treatment and outcomes among older patients with myocardial infarction. Mobility impairment, a marker for frailty, modifies the association between advanced age and treatments as well as outcomes.