Weight Gain After Heart Surgery: What Should Patients Know?
Written By: Allison DeMajistre, BSN, RN, CCRN
Medical Expert: Richard Kim, MD, Director of Pediatric and Congenital Cardiac Surgery, Cedars-Sinai, Los Angeles, California
Reviewed By: Adam Pick, Patient Advocate, Author & Website Founder
Published: May 6, 2025
When patients are preparing for heart valve surgery, they anticipate pain, fatigue, and even post-operative complications (e.g. atrial fibrillation) that may be uncomfortable. However, many patients aren’t prepared for the 10 to 20 pounds of post-operative weight gain they may experience.
We received a patient question from David, who asked, “I had heart valve surgery and gained 20 pounds immediately after the operation. Why is there so much weight gain following cardiac surgery?” To answer David’s question, I asked Dr. Richard Kim, the Director of Pediatric and Congenital Cardiac Surgery at Cedars-Sinai in Los Angeles, California.
Facts About Weight Gain After Heart Surgery
Here are several key insights shared by Dr. Kim in our discussion:
- What causes the weight gain after surgery? “This is a great question,” said Dr. Kim. “Surgery involves using the heart-lung machine, which creates a lot of inflammation throughout the body.” Dr. Kim explained that the body responds to inflammation by making the blood vessels in the heart leaky. Up to 20 pounds of fluid leaking from the heart can enter the soft tissue and cause weight gain.
- How is weight gain treated? Kim said patients are given diuretics after surgery to help their bodies get rid of the extra fluid, and over time, their weight will return to normal.
Thanks Dr. Kim and Cedars-Sinai!
On behalf of David and all the patients at HeartValveSurgery.com, we want to thank Dr. Richard Kim and his team at Cedars-Sinai Medical Center for everything they do for heart valve patients in our community and worldwide.
Related links:
- Ask Dr. Richard Kim: Pediatric Heart Valve Surgery
- Surgeon Q&A: Top 5 Complications After Heart Valve Surgery
Keep on tickin!
Adam
P.S. For the deaf and hard-of-hearing members of our patient community, we have provided a written transcript of our interview with Dr. Kim below.
Written by Adam Pick
- Patient & Website Founder
Video Transcript:
Adam Pick: Hi everybody. It’s Adam with HeartValveSurgery. com and we are at Cedars-Sinai Medical Center in Los Angeles, California. I am thrilled to be joined by Dr. Richard Kim, who is the Director of Pediatric and Congenital Cardiac Surgery. Dr. Kim, it is great to see you again and thanks so much for being with me today. Thanks for having me. Yeah, so we’re answering some patient questions here at Cedars.
This just came in from David and he asks, “I had heart valve surgery and gained 20 pounds immediately. After the operation, why is there so much weight gain following cardiac surgery?”
Dr. Richard Kim: This is a great question. So, surgery involves the use of the heart lung machine. And the heart lung machine creates a lot of inflammation throughout the body.
The body responds to inflammation the very same way. Actually, only one way. And that’s by making the blood vessels in the heart very leaky. And a lot of the fluid in your body goes out into your soft tissue and it can be up to 20 pounds.
And that’s why on the few days after surgery we give diuretics for you to lose the water weight.
Adam Pick: And I’m guessing the diuretics over time take that weight gain back to normal?
Dr. Richard Kim: Yes. Back to normal.
Adam Pick: Great. Well, David, I hope that helped you. I know it helped me and Dr.
Kim on behalf of David and all the patients at HeartValveSurgery. com. Thanks for everything you and your team are doing here at Cedars-Sinai Medical Center in Los Angeles.
Dr. Richard Kim: Thank you very much.
