Publications by authors named "Shant Vartanian"

Background: A mature arteriovenous fistula (AVF) is the preferred hemodialysis access owing to its durability and lower risk of complications. Various factors have been implicated as predictors for maturation, including vein diameter and access type. Vein distensibility, which refers to the ability of the vein to dilate in response to changes in blood flow and pressure, has been proposed as a potential predictor for maturation, but its utility remains poorly studied.

View Article and Find Full Text PDF

Objective: Major adverse limb event-free survival (MALE-FS) differed significantly by initial revascularization approach in the BEST-CLI randomized trial. The BEST-CLI trial represented a highly selected subgroup of patients seen in clinical practice; thus, we examined the endpoint of MALE-FS in an all-comers tertiary care practice setting.

Methods: This is a single-center retrospective study of consecutive, unique patients who underwent technically successful infrainguinal revascularization for chronic limb-threatening ischemia (2011-2021).

View Article and Find Full Text PDF
Article Synopsis
  • Reliable large animal models for renal failure are essential for advancing renal replacement therapies (RRT) that can be used in humans.
  • This study introduced a novel embolization-to-implantation protocol that successfully integrated a silicon nanopore membrane hemodialyzer (SNMHD) into a swine model of renal failure.
  • The findings showed promising clearance rates for creatinine and urea using the SNMHD, suggesting potential for future clinical applications with fully implantable devices.*
View Article and Find Full Text PDF

The definitive treatment for end-stage renal disease is kidney transplantation, which remains limited by organ availability and post-transplant complications. Alternatively, an implantable bioartificial kidney could address both problems while enhancing the quality and length of patient life. An implantable bioartificial kidney requires a bioreactor containing renal cells to replicate key native cell functions, such as water and solute reabsorption, and metabolic and endocrinologic functions.

View Article and Find Full Text PDF
Article Synopsis
  • Clinical islet transplantation for type 1 diabetes is hindered by the lack of pancreas donors and the necessity for lifelong immunosuppression.
  • Researchers are exploring a new bioartificial pancreas (iBAP) that utilizes silicon nanopore membranes to potentially replace the need for immunosuppressants while maintaining islet function.
  • Their findings indicate that for effective insulin production, specific perifusion rates must be met, with successful insulin secretion responses observed in both lab and live pig models.
View Article and Find Full Text PDF

Objective: There are currently no specific biomarkers to identify patients with abdominal aortic aneurysms (AAAs). Circulating exosomes contain microRNAs (miRNA) that are potential biomarkers for the presence of disease. This study aimed to characterize the exosomal miRNA expression profile of patients with AAAs in order to identify novel biomarkers of disease.

View Article and Find Full Text PDF

Objective: The SVS Wound, Ischemia, foot Infection (WIfI) limb staging system was established to estimate risk of major amputation in chronic limb-threatening ischemia (CLTI) and better stratify outcomes comparisons. There is little data on treatment outcomes beyond 1 year based on presenting WIfI stage.

Methods: This is a single-institution retrospective study of 413 patients who underwent infrainguinal revascularization for CLTI (2011-2021) with data available for WIfI staging.

View Article and Find Full Text PDF

Objective: Pedal medial arterial calcification (pMAC) is associated with major amputation in patients with chronic limb-threatening ischemia (CLTI). We hypothesize that this association would be related to unresolved distal ischemia. We investigated relationships across pMAC score, hemodynamic change, and major amputation after infrainguinal revascularization for CLTI.

View Article and Find Full Text PDF
Article Synopsis
  • In 2019, new guidelines were created to help understand a condition called chronic limb-threatening ischemia (CLTI) and a concept called limb-based patency (LBP), which means keeping blood flow in a targeted artery after treatment.
  • The study looked at patients from 2016 to 2019 who had surgery for CLTI, focusing on whether keeping LBP was connected to serious problems like amputations or surgeries after treatment.
  • Out of 184 limbs studied, many patients had diabetes and severe tissue loss; results showed that losing LBP was a strong predictor of future serious limb problems.
View Article and Find Full Text PDF

Objective: Patients undergoing revascularization for chronic limb-threatening ischemia (CLTI) are at elevated risk for both mortality and limb loss. To facilitate therapeutic decision-making, a mortality prediction model derived from the Vascular Quality Initiative (VQI) database has stratified patients into low, medium, and high risk, defined by 30-day mortality estimates of ≤3%, 3%-5%, or >5% and 2-year mortality estimates of ≤30%, 30%-50%, or ≥50%, respectively. The purpose of this study was to compare expected mortality risk derived from this model with observed outcomes in a tertiary center.

View Article and Find Full Text PDF

Objective: Type A or ascending aortic dissection is an acute life-threatening condition with high morbidity and mortality. Open surgery remains the standard of care. The development of minimally invasive endografts for type A aortic dissection (TAAD) will require a detailed understanding of the dissection and aortic root anatomy to determine patient eligibility and optimal device specifications.

View Article and Find Full Text PDF

Objective: The medial arterial calcification (MAC) score is a simple metric that describes the burden of inframalleolar calcification using a plain foot radiograph. We hypothesized that a higher MAC score would be independently associated with the risk of major amputation in patients with chronic limb-threatening ischemia (CLTI).

Methods: We performed a single-institution, retrospective study of 250 patients who had undergone infrainguinal revascularization for CLTI from January 2011 to July 2019 and had foot radiographs available for MAC score calculation.

View Article and Find Full Text PDF

Objectives: To describe contemporary outcomes from a single center capable of both complex open and endovascular aortic repair for paravisceral aortic aneurysms (PVAAA).

Methods: Data on all patients receiving open or endovascular (endo) treatment for aortic aneurysms with proximal extent at or above the renal arteries and distal to the inferior pulmonary ligament (IPL) were reviewed. Coarsened exact matching (CEM) on age, aneurysm type, gender, coronary artery disease (CAD), previous aortic surgery and symptomatic status created balanced cohorts for outcomes comparisons.

View Article and Find Full Text PDF

Rationale & Objective: Percutaneous arteriovenous fistulas (AVF) are created by establishing a proximal forearm anastomosis and offer a safe and reliable vascular access. This study compares the Ellipsys percutaneous AVF with a proximal forearm Gracz-type surgical AVF, chosen for comparison as it is constructed at the same anatomical site.

Study Design: Retrospective study of prospectively collected clinical data.

View Article and Find Full Text PDF

Objective: The Global Limb Anatomic Staging System (GLASS) has been proposed to facilitate clinical decision-making regarding revascularization for chronic limb threatening ischemia (CLTI). The purpose of the present study was to define its relationship to the treatment outcomes in CLTI.

Methods: Consecutive patients who had undergone peripheral angiography for rest pain or tissue loss from January 2017 to July 2019 at a tertiary referral center with a dedicated limb preservation program were reviewed.

View Article and Find Full Text PDF

A growing, but poorly defined subset of patients with chronic limb-threatening ischemia (CLTI) have "no option" for revascularization. One notable subgroup includes patients with severe ischemia and advanced pedal artery occlusive disease, termed "desert foot," who are at high risk for major amputation due to a lack of conventional revascularization options. Although new therapies are being developed for no-option patients with desert foot anatomy, this subgroup and the broader group of no-option patients are not well defined, limiting the ability to evaluate outcomes.

View Article and Find Full Text PDF

With the aggressive resource conservation necessary to face the coronavirus disease 2019 pandemic, vascular surgeons have faced unique challenges in managing the health of their high-risk patients. An early analysis of patient outcomes after pandemic-related practice changes suggested that patients with chronic limb threatening ischemia have been presenting with more severe foot infections and are more likely to require major limb amputation compared with 6 months previously. As our society and health care system adapt to the new changes required in the post-coronavirus disease 2019 era, it is critical that we pay special attention to the most vulnerable subsets of patients with vascular disease, particularly those with chronic limb threatening ischemia and limited access to care.

View Article and Find Full Text PDF

Objective: Acute iliofemoral artery thrombosis (IFAT) can occur in critically ill neonates and infants who require indwelling arterial cannulas for monitoring or as a consequence of cardiac catheterization. Guidelines suggest treatment with anticoagulation, but evidence supporting the optimal duration of therapy and the role of surveillance ultrasound is limited. The objectives of this study were to characterize the kinetics of thrombus resolution and to define an appropriate duration of anticoagulation and interval for surveillance ultrasound.

View Article and Find Full Text PDF

Objective: Antegrade femoral artery access is often used for ipsilateral infrainguinal peripheral vascular intervention. However, the use of closure devices (CD) for antegrade access (AA) is still considered outside the instructions for use for most devices. We hypothesized that CD use for antegrade femoral access would not be associated with an increased odds of access site complications.

View Article and Find Full Text PDF

Objective: Regional anesthesia (RA)-induced vasodilation increases the proportion of patients with vein anatomy suitable for arteriovenous fistula (AVF) creation. The functional outcomes of AVFs created with veins initially small for size on preoperative duplex ultrasound mapping (≤2.4 mm) that are recruited under RA have not been clearly defined.

View Article and Find Full Text PDF

Visceral artery aneurysms are rare in infants and children. The majority of cases are caused by genetic syndromes, trauma, or infection. Although the majority of aneurysms are asymptomatic, visceral artery aneurysms can present with abdominal pain, nausea/vomiting, or rupture.

View Article and Find Full Text PDF

Objectives: HIV and hepatitis C virus (HCV) have been associated with cardiovascular disease (CVD), but it is unclear whether HIV and HCV are also associated with peripheral artery disease (PAD). We examined the association of HIV, HCV, and traditional CVD risk factors with PAD in the Women's Interagency HIV Study, a multicenter US cohort.

Methods: In this cross-sectional study, ankle-brachial index was estimated using Doppler ultrasound and manual sphygmomanometer in 1899 participants aged more than 40 years with HIV/HCV coinfection, HCV or HIV monoinfection, or neither infection.

View Article and Find Full Text PDF

Current paradigms of CD8 T cell-mediated protection in HIV infection center almost exclusively on studies of peripheral blood, which is thought to provide a window into immune activity at the predominant sites of viral replication in lymphoid tissues (LTs). Through extensive comparison of blood, thoracic duct lymph (TDL), and LTs in different species, we show that many LT memory CD8 T cells bear phenotypic, transcriptional, and epigenetic signatures of resident memory T cells (T). Unlike their circulating counterparts in blood or TDL, most of the total and follicular HIV-specific CD8 T cells in LTs also resemble T Moreover, high frequencies of HIV-specific CD8 T with skewed clonotypic profiles relative to matched blood samples are present in LTs of individuals who spontaneously control HIV replication in the absence of antiretroviral therapy (elite controllers).

View Article and Find Full Text PDF