Publications by authors named "Tabbara M"

Background: Kidney transplantation is the gold standard treatment for end-stage kidney disease in children. Rare genetic systemic diseases associated with cystic kidney disease such as COL4A1-related disorder and oral facial digital syndrome type 1 could contribute to end-stage kidney disease in the pediatric population but there is scarce evidence in the literature regarding kidney transplant outcomes in these cases.

Case Presentation: We report a case of a 5-year-old male with COL4A1-related disorder who received a living-related donor kidney transplant from his mother.

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Modern competing risks analysis has 2 primary goals in clinical epidemiology as follows: (i) to maximize the clinician's knowledge of etiologic associations existing between potential predictor variables and various cause-specific outcomes via cause-specific hazard models, and (ii) to maximize the clinician's knowledge of noteworthy differences existing in cause-specific patient risk via cause-specific subdistribution hazard models (cumulative incidence functions [CIFs]). A perfect application exists in analyzing the following 4 distinct outcomes after listing for a deceased donor kidney transplant (DDKT): (i) receiving a DDKT, (ii) receiving a living donor kidney transplant (LDKT), (iii) waitlist removal due to patient mortality or a deteriorating medical condition, and (iv) waitlist removal due to other reasons. It is important to realize that obtaining a complete understanding of subdistribution hazard ratios (HRs) is simply not possible without first having knowledge of the multivariable relationships existing between the potential predictor variables and the cause-specific hazards (perspective #1), because the cause-specific hazards form the "building blocks" of CIFs.

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Arteries and veins develop different types of occlusive diseases and respond differently to injury. The biological reasons for this discrepancy are not well understood, which is a limiting factor for the development of vein-targeted therapies. This study contrasts human peripheral arteries and veins at the single-cell level, with a focus on cell populations with remodeling potential.

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Background: A limiting factor in expanding the kidney donor pool is donor kidneys with renal tumors or cysts. Partial nephrectomy (PN) to remove these lesions prior to transplantation may help optimize organ usage without recurrence of malignancy or increased risk of complications.

Methods: We retrospectively analyzed all recipients of a living or deceased donor graft between February 2009 and October 2022 in which a PN was performed prior to transplant due to the presence of one or more concerning growths.

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Background: At our center, surgical modifications to the conventional kidney transplant technique were developed with two goals in mind: to minimize the risk of developing post-transplant urologic/vascular/other surgical complications, and to simultaneously eliminate the need for initial ureteral stent placement and surgical drainage.

Methods: Here, the authors describe these modifications along with (what we believe are) their advantages over the conventional technique: creating an abdominal flap for easier abdominal closure (reflecting the parietal peritoneum from the abdominal wall), mobilizing the bladder before transplant (creating more space for bladder dissection, allowing it to move upward during abdominal wall closure), minimizing the dissection of iliac vessels to only anterior lymphatic tissue (attempting to minimize the incidence of fluid collections), using plastic arterial vascular bulldog clamps (causing less trauma to the iliac artery), performing vascular anastomosis of the renal artery first (making it easier for the surgeon to perform the anastomoses), creating longer ureteral spatulation, and inclusion of bladder mucosa along with some detrusor muscle layer in performing the ureteral anastomosis (attempting to minimize the incidence of urologic complications). Of note, no initial ureteral stent placement or surgical drainage was used.

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Background: The gold standard treatment for renal cell carcinoma (RCC) with tumor thrombus (TT) is complete surgical excision. The surgery is complex and challenging to the surgeon, especially with large tumor thrombus extending into the inferior vena cava (IVC) and right atrium. Traditionally, these difficult cases required the use of cardiopulmonary bypass (CPB) with or without deep hypothermic cardiac arrest, but in recent years, different surgical techniques derived from the field of liver transplantation have been used in efforts to avoid CPB.

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Leiomyosarcomas (LMS) of the inferior vena cava (IVC) are a rare form of retroperitoneal malignancy, and their venous extension to the right atrium is an even rarer event. These tumors pose a unique surgical challenge and often require a multidisciplinary team-based approach for their surgical treatment. We present a case of a 68-year-old man with primary LMS of the IVC with a tumor thrombus extending into the right atrium that was initially deemed inoperable.

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The venous system has been historically understudied despite its critical roles in blood distribution, heart function, and systemic immunity. This study dissects the microanatomy of upper arm veins at the single cell level, and how it relates to wall structure, remodeling processes, and inflammatory responses to injury. We applied single-cell RNA sequencing to 4 non-diseased human veins (3 basilic, 1 cephalic) obtained from organ donors, followed by bioinformatic and histological analyses.

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Background: Right versus left kidney donor nephrectomy remains a controversial topic in renal transplantation given the increased incidence of right kidney vascular anomalies and associated venous thrombosis. We present the case of a 3-year-old pediatric recipient with urethral atresia and end-stage kidney disease who received a robotically procured living donor right pelvic kidney with two short same-size renal veins and a short ureter.

Methods: We utilized a completely deceased iliac vein system (common iliac vein with both external and internal veins) to extend the two renal veins.

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More favorable clinical outcomes with medium-term follow-up have been reported among kidney transplant recipients receiving maintenance therapy consisting of "reduced-tacrolimus (TAC) dosing," mycophenolate mofetil (MMF), and low-dose corticosteroids. However, it is not clear whether long-term maintenance therapy with reduced-calcineurin inhibitor (CNI) dosing still leads to reduced renal function. A prospectively followed cohort of 150 kidney transplant recipients randomized to receive TAC/sirolimus (SRL) versus TAC/MMF versus cyclosporine microemulsion (CSA)/SRL, plus low-dose maintenance corticosteroids, now has 20 years of post-transplant follow-up.

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In intestinal transplantation, while other centers have shown that liver-including allografts have significantly more favorable graft survival and graft loss-due-to chronic rejection (CHR) rates, our center has consistently shown that modified multivisceral (MMV) and full multivisceral (MV) allografts have significantly more favorable acute cellular rejection (ACR) and severe ACR rates compared with isolated intestine (I) and liver-intestine (LI) allografts. In the attempt to resolve this apparent discrepancy, we performed stepwise Cox multivariable analyses of the hazard rates of developing graft loss-due-to acute rejection (AR) vs. CHR among 350 consecutive intestinal transplants at our center with long-term follow-up (median: 13.

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Most patients with end-stage renal disease (ESRD) and advanced chronic kidney disease (CKD) choose hemodialysis as their treatment of choice. Thus, upper-extremity veins provide a functioning arteriovenous access to reduce dependence on central venous catheters. However, it is unknown whether CKD reprograms the transcriptome of veins and primes them for arteriovenous fistula (AVF) failure.

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Background And Objective: Renal cell carcinoma (RCC) accounts for 2-3% of all malignant disease in adults. RCC propagates into the renal vein and inferior vena cava (IVC) in up to 25% of patients with RCC. Despite advances in medical management such as immunotherapy, surgical resection remains the gold standard treatment of RCC with venous tumor thrombus (TT) extension.

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Introduction: The molecular transformation of the human preaccess vein after arteriovenous fistula (AVF) creation is poorly understood. This limits our ability to design efficacious therapies to improve maturation outcomes.

Methods: Bulk RNA sequencing (RNA-seq) followed by paired bioinformatic analyses and validation assays were performed in 76 longitudinal vascular biopsies (veins and AVFs) from 38 patients with stage 5 chronic kidney disease or end-stage kidney disease undergoing surgeries for 2-stage AVF creation (19 matured, 19 failed).

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In testing the prognostic value of the occurrence of an intervening event (clinical event that occurs posttransplant), 3 proper statistical methodologies for testing its prognostic value exist (time-dependent covariate, landmark, and semi-Markov modeling methods). However, time-dependent bias has appeared in many clinical reports, whereby the intervening event is statistically treated as a baseline variable (as if it occurred at transplant). Using a single-center cohort of 445 intestinal transplant cases to test the prognostic value of first acute cellular rejection (ACR) and severe (grade of) ACR on the hazard rate of developing graft loss, we demonstrate how the inclusion of such time-dependent bias can lead to severe underestimation of the true hazard ratio (HR).

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Background: This study compares the presentation, management, and outcomes of patients undergoing endovascular abdominal aortic aneurysm repair (EVAR), based on their weight status as defined by their body mass index (BMI).

Methods: Patients with primary EVAR for ruptured and intact abdominal aortic aneurysm (AAA) were identified in the National Surgical Quality Improvement Program database (2016-2019). Patients were categorized by weight status (underweight: BMI < 18.

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Purpose: The surgical treatment for adrenocortical carcinoma with venous tumor invasion remains a challenge for surgeons. A critical factor in determining the surgical approach is utilizing a classification system that accurately defines the tumor thrombus level.

Methods: Olivero and colleagues report their experience regarding the feasibility of mini-invasive surgery for adrenocortical carcinoma with venous tumor invasion.

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Renal cell carcinoma (RCC) accounts for 2-3% of all malignant disease in adults and has a propensity to infiltrate the surrounding adjacent structures with a biologic predisposition for vascular invasion. This tropism for the venous system facilitates propagation into the renal vein and inferior vena cava (IVC) in up to 25% of patients with RCC. Surgical resection remains the mainstay treatment for RCC with venous tumor thrombus (TT) extension and the only hope for a potential cure.

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Background: Surgical groin wounds are at risk of delayed healing and infection, leading to costly and prolonged postoperative recoveries. This study assesses the use of closed suction drains (CSDs) as a wound care adjunct in groin incisions to prevent surgical site infections (SSI).

Methods: A single-center retrospective review was performed on 210 consecutive patients after vascular surgery with common femoral artery exposure from 2016 to 2021.

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Renal cell carcinoma (RCC) accounts for 2-3% of all malignant disease in adults, with 30% of RCC diagnosed at locally advanced or metastatic stages of disease. A form of locally advanced disease is the tumor thrombus (TT), which commonly grows from the intrarenal veins, through the main renal vein, and up the inferior vena cava (IVC), and rarely, into the right cardiac chambers. Advances in all areas of medicine have allowed increased understanding of the underlying biology of these tumors and improved preoperative staging.

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Background: Kidney allografts with multiple renal arteries (MRA) are not infrequent and have been historically associated with a higher risk of developing vascular and urologic complications. Reports of kidney transplantation using MRA allografts in the pediatric population remain scarce. The aim of this study was to evaluate if transplantation of allografts with MRA with a surgical intent of creating a single arterial inflow using vascular reconstruction techniques when required, and without the routine use of surgical drains or ureteral stents, is associated with an increased risk of complications when compared to single renal artery (SRA) grafts.

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