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Dr. Mareno is a board-certified colorectal surgeon who was raised in East Cobb, Georgia. He graduated Magna Cum Laude from Berry College in 1999 and Emory University School of Medicine in 2003. He completed his general surgery residency at the University of California San Diego Medical Center. There, he was the recipient of the Halasz Award for Excellence in Surgical Consultation. Dr. Mareno completed his fellowship training in Colon & Rectal Surgery at the Cleveland Clinic in Florida and has been practicing here at ATL Colorectal Surgery since 2009.
Dr. Mareno practices all aspects of colon and rectal surgery including treatment of Crohn’s disease, ulcerative colitis, colorectal and anal cancer, diverticulitis, hemorrhoids, anal fissures, pelvic floor disorders, HPV treatment/monitoring, and fecal incontinence. He has advanced training in minimally invasive surgery, including laparoscopy, and transanal minimally invasive surgery (TAMIS). Dr. Mareno is a Fellow of the American College of Surgeons and a Fellow of the American Society of Colon and Rectal Surgeons. He is the Chair of the Department of Surgery at Piedmont Atlanta Hospital and the Vice Chair for the Surgical Services Governance Council for the Piedmont Healthcare System. He has been named to the Castle Connolly and Atlanta Magazine Top Doctors list every year since 2015.
Dr. Evan Feldman is a board-certified colorectal surgeon who practices all aspects of colon and rectal surgery. He earned his bachelor’s degree from Brown University in Providence, Rhode Island, where he studied public health and graduated with honors. He received his medical degree from Emory University, where he graduated with honors and was a member of the Alpha Omega Alpha Honor Medical Society. He completed his surgical internship and residency at New York Presbyterian Hospital/Weill-Cornell Medical Center and Memorial Sloan-Kettering Cancer Center in New York City. He completed his fellowship in colon and rectal surgery at Barnes-Jewish Hospital/Washington University School of Medicine in St. Louis, Missouri.
Dr. Feldman is the service chair for colorectal surgery at Piedmont Atlanta Hospital, the medical director of the Colorectal Multidisciplinary Tumor Board for the Piedmont Healthcare System, and serves in leadership positions on several other hospital and system-wide committees. In 2017, he received the Piedmont Clinic Chairman’s Service Award recognizing his work reducing colorectal surgery infections across the Piedmont Healthcare system. In 2018, he received the William C. Waters Award for Clinical Excellence, chosen by the Piedmont Medical Staff for superior patient care and leadership. Dr. Feldman is also an adjunct Clinical Assistant Professor at Mercer Health Sciences Center. He is a Fellow of the American College of Surgeons and a Fellow of the American Society of Colon and Rectal Surgeons. He has advanced training in colonoscopy and minimally invasive surgery, including laparoscopy, robotic-assisted surgery, transanal endoscopic microsurgery (TEMS) and transanal minimally invasive surgery (TAMIS).
Dr. Evan Feldman has been named a TOP DOCTOR by Castle Connolly and Atlanta Magazine in 2019, 2020, 2021, 2022, 2023, 2024, and 2025.
Dr. Swetha Ramakrishnan is a board-certified colorectal surgeon who grew up in North Brunswick, New Jersey. She graduated with the highest distinction from a combined 7-year BS/MD program from Pennsylvania State University with a degree in life science and a minor in German language. She received her MD degree from Jefferson Medical College where she was inducted into the Alpha Omega Alpha Honor Medical Society. She then completed her general surgery residency at the Emory University School of Medicine, where she also completed a 2-year post-doctoral research fellowship in transplant immunology. She completed her fellowship in colon and rectal surgery at Barnes-Jewish Hospital/Washington University School of Medicine in St. Louis, Missouri.
Dr. Ramakrishnan is a Fellow of the American College of Surgeons and a Fellow of the American Society of Colon and Rectal Surgeons. She treats all colon and rectal conditions including colon cancer, anal cancer, inflammatory bowel disease, diverticulitis, hemorrhoids, fissures, fistulae, abscesses, and pilonidal disease. She has a particular interest in the diagnosis and treatment of pelvic floor disorders including fecal incontinence, constipation, levator syndrome, and post-partum anorectal disease. In addition to colonoscopy, laparoscopy, and transanal minimally invasive surgery (TAMIS), she performs sacral neuromodulation (SNS) for fecal incontinence, in-office anorectal manometry, and the Cleft Lift procedure for pilonidal disease. Dr. Ramakrishnan also leads the anal cancer prevention program and completed the ASCCP course on HPV-related genital tract disorders and High-Resolution Anoscopy (HRA) in 2017. She performs in-office HRA to detect and treat high-grade anal dysplasia, a known risk for development of squamous cell cancer of the anus and cervix. Dr. Ramakrishnan is currently the chairwoman of the Piedmont Atlanta Hospital Ethics Committee and Secretary/Treasurer of the Piedmont Atlanta Hospital Medical Staff. She also serves as an adjunct clinical faculty member for Mercer University’s College of Health Professions. Dr. Ramakrishnan was named a Top Doctor by Atlanta Magazine in 2022, 2023, and 2024.
Dr. Daniel Sarmiento is our newest physician at ATL Colorectal Surgery and is a board-certified colorectal surgeon who practices all aspects of colon and rectal surgery. He was born in Bogota, Colombia and attended Universidad del Rosario, one of the oldest and most prestigious medical schools in Colombia. He then started a rigorous general surgery residency at the University of Pennsylvania for 2 years and completed his training at Christiana Care Health System in Delaware. Dr. Sarmiento completed his Colon and Rectal Surgery Fellowship with the Lehigh Valley Health Network in Allentown Pennsylvania in 2017. He was then an attending surgeon at Somerset Hospital, Branch of the University of Pittsburgh Medical Center, where he served as the chair of the surgery department for many years.
In 2022, he moved to Georgia and worked with the Northeast Georgia Health System primarily based in Braselton, and served as a core faculty member for the general surgery residency program. He was nominated as a Top Doctor by Georgia Trend Magazine in 2023.
Dr. Sarmiento is a current Fellow of the American College of Surgeons and a Fellow of the American Society of Colon and Rectal Surgeons, where he actively serves on different committees. He has a special interest in minimally invasive surgical approaches, specifically robotic transabdominal surgery and robotic transanal minimally invasive surgery (R-TAMIS), as well as laparoscopy. He practices all aspects of colorectal surgery including treating malignant diseases of the colon, rectum and anus, as well as benign conditions such as inflammatory bowel disease, diverticular disease, constipation, and anorectal diseases including incontinence, hemorrhoids, fissures, and anal fistulae. He is also a firm believer in the importance of preventive medicine and performs colonoscopy and advanced polyp retrieval. Dr. Sarmiento is now accepting new patients at ATL Colorectal, P.C. on the Piedmont Atlanta Campus.
Vivie Lee is a nationally certified Physician Assistant who grew up in Livingston, New Jersey. She moved to Atlanta to obtain her undergraduate degree at Emory University, completing a double major in Biology and Music. She then completed a Masters of Medical Science at Mercer University’s Physician Assistant Program. She is a member of the American Academy of Physician Assistants, the American Association of Surgical Physician Assistants, and the Georgia Association of Physician Assistants.
Dr. Monica Hum is a board-certified colorectal surgeon who started practicing at Piedmont Hospital in 2003 and founded ATL Colorectal Surgery, PC in 2007. She retired from clinical practice in 2021 to join the Piedmont Healthcare System as Chief Medical Officer of Piedmont Rockdale Hospital.
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