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Your search keyword '"Sahakyan, Artur A."' showing total 16 results
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16 results on '"Sahakyan, Artur A."'

1. Billroth-I anastomosis in distal subtotal gastrectomy for non-early gastric adenocarcinoma

Author

Shahbazyan Sevak S, Sahakyan Mushegh A, Gabrielyan Artak, Lai Xiaoran, Martirosyan Aram, Petrosyan Hmayak, Yesayan Shushan, and Sahakyan Artur M

Subjects
gastrectomy, anastomosis, billroth-i, billroth-ii, adenocarcinoma, Medical physics. Medical radiology. Nuclear medicine, R895-920
Abstract

Billroth-I (B-I) anastomosis is known as a simple and physiological reconstruction method after distal subtotal gastrectomy for early gastric cancer. Yet its role and oncological validity in non-early gastric adenocarcinoma (NEGA) remain unclear.

Published
2023
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2. Statistical inference for stationary linear models with tapered data

Author

Ginovyan, Mamikon S. and Sahakyan, Artur A.

Subjects
Mathematics - Statistics Theory, 62F10, 62F12, 60G10, 62G05, 62G10, 60G15
Abstract

In this paper, we survey some recent results on statistical inference (parametric and nonparametric statistical estimation, hypotheses testing) about the spectrum of stationary models with tapered data, as well as, a question concerning robustness of inferences, carried out on a linear stationary process contaminated by a small trend. We also discuss some question concerning tapered Toeplitz matrices and operators, central limit theorems for tapered Toeplitz type quadratic functionals, and tapered Fej\'er-type kernels and singular integrals. These are the main tools for obtaining the corresponding results, and also are of interest in themselves. The processes considered will be discrete-time and continuous-time Gaussian, linear or L\'evy-driven linear processes with memory., Comment: arXiv admin note: substantial text overlap with arXiv:2102.00343

Published
2021

5. Standard and multivisceral colectomy in locally advanced colon cancer

Author

Sahakyan Artur M., Aleksanyan Andranik, Batikyan Hovhannes, Petrosyan Hmayak, and Sahakyan Mushegh А.

Subjects
colectomy, colon cancer, locally advanced, multivisceral, morbidity, Medical physics. Medical radiology. Nuclear medicine, R895-920
Abstract

Management of locally advanced colon cancer (LACC) is challenging. Surgery is the mainstay of the treatment, yet its outcomes remain unclear, especially in the setting of multivisceral resections. The aim of the study was to examine the outcomes of standard and multivisceral colectomy in patients with LACC.

Published
2020
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6. The Trace Problem for Toeplitz Matrices and Operators and its Impact in Probability

Author

Ginovyan, Mamikon S., Sahakyan, Artur A., and Taqqu, Murad S.

Subjects
Mathematics - Probability
Abstract

The trace approximation problem for Toeplitz matrices and its applications to stationary processes dates back to the classic book by Grenander and Szeg\"o, "Toeplitz forms and their applications". It has then been extensively studied in the literature. In this paper we provide a survey and unified treatment of the trace approximation problem both for Toeplitz matrices and for operators and describe applications to discrete- and continuous-time stationary processes. The trace approximation problem serves indeed as a tool to study many probabilistic and statistical topics for stationary models. These include central and non-central limit theorems and large deviations of Toeplitz type random quadratic functionals, parametric and nonparametric estimation, prediction of the future value based on the observed past of the process, etc. We review and summarize the known results concerning the trace approximation problem, prove some new results, and provide a number of applications to discrete- and continuous-time stationary time series models with various types of memory structures, such as long memory, anti-persistent and short memory.

Published
2013

8. Recurrence After Colectomy for Locally Advanced Colon Cancer: Experience from a Developing Country.

Author

Sahakyan, Artur M., Aleksanyan, Andranik, Batikyan, Hovhannes, Petrosyan, Hmayak, Yesayan, Shushan, and Sahakyan, Mushegh A.

Abstract

Risk factors for disease recurrence following curative resection for locally advanced colon cancer (LACC) remain unclear as conflicting results have been reported in the literature. The aim of this study was to examine these factors in the setting of developing country's health care system affected by limited accessibility to the multimodal cancer treatment. Patients who had undergone curative colon resection for LACC between 2004 and 2018 were included. Data were obtained from a prospectively maintained database. Factors associated with disease recurrence, types of recurrence and recurrence-free survival were studied. A total of 118 patients with LACC were operated within the study period. Median follow-up was 36 (2-147) months. Adjuvant therapy was used in 41 (34.7%) patients and 62 (52.5%) were diagnosed with recurrence. In the multivariable analysis, disease recurrence was associated with tumor and nodal stages, as well as with the lymph node yield. Local recurrence, distant metastases, and peritoneal carcinomatosis were observed in 8 (6.8%), 30 (25.4%), and 24 (20.3%) patients, respectively. Early recurrence was diagnosed in 27 (22.9%) cases with peritoneal carcinomatosis being its most common type. Preoperative serum CA 19–9 levels, tumor, and nodal stages were linked to recurrence-free survival in the univariable analysis. Only tumor stage remained such in the multivariable model. Our findings suggest that lymph node yield, tumor, and nodal stages are associated with recurrence following curative resection for LACC. [ABSTRACT FROM AUTHOR]

Published
2023
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14. Gastrectomy for Gastric Cancer in Patients with BMI = 30 kg/m2

Author

Sahakyan, Mushegh A., Shahbazyan, Sevak S., Martirosyan, Aram, Gabrielyan, Artak, Petrosyan, Hmayak, and Sahakyan, Artur M.

Abstract

Obesity is a major health issue in the modern world population and a risk factor for surgical procedures. This study examined perioperative and oncologic results of gastrectomy in obese patients diagnosed with gastric cancer. BMI =30 kg/m2was used to designate obesity. Five hundred and one patients were operated throughout the study period (2009–2018). The outcomes in obese patients (n = 205) were compared with those with normal weight (n = 171) and overweight (n = 125). The mean BMI was significantly different between the groups: 21.9 versus26.7 versus33.3 kg/m2(P< 0.01), respectively. Obesity was associated with higher incidence of comorbidities, longer operative time, and increased blood loss. Postoperative and short-term oncologic outcomes were similar. Median follow-up was 24 months with similar recurrence rates in the three groups. Median survival was comparable between the normal weight, overweight, and obese patients—36 (27–45) versus42 (30–53) versus32 (17–47) months, respectively (P= 0.63). Obesity itself does not deteriorate the surgical outcomes of gastrectomy in patients with gastric cancer. Although technically demanding in obese patients, adequate lymph node yield and satisfactory long-term oncologic outcomes can be achieved in this group.

Published
2020
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