President Donald Trump flew to Walter Reed National Military Medical Center Monday and visited FirstLady Melania Trump hours after she underwent a kidney procedure.

The first lady's office announced the first lady had the procedure Monday. President Trump was at the White House Monday when her surgery occurred.

The president flew via Marine One Monday afternoon to visit the flagship military hospital in Bethesda, Maryland – avoiding a movement that otherwise might have snarled Washington D.C.'s traffic at rush hour.

Melania Trump underwent an embolization procedure, likely to remove a cyst from her kidney. Her office said it was benign, or non-cancerous.

Trump tweeted about the visit while he was en route. 'Heading over to Walter Reed Medical Center to see our great First Lady, Melania. Successful procedure, she is in good spirits. Thank you to all of the well-wishers!'

First Lady Melania Trump underwent surgery at Walter Reed National Military Medical Center in a kidney procedure, her office announced Monday

Past medical procedures by first ladies while in the White House Nancy Reagan: Got a mastectomy in 1987 as treatment for breast cancer Rosalynn Carter: Surgery to remove a lump from her breast in 1977. The tumor was benign. Betty Ford: Had a mastectomy in 1974 Source: CNN Advertisement

The president spent about an hour at the hospital, then traveled back to the White House via motorcade due to a powerful thunderstorm that was making its way through the Washington, D.C. area.

The procedure should have the first lady in the hospital through the week – an extended stay that could speak to the seriousness of the needed time for recovery and monitoring.

The president didn't respond to questions as he approached the presidential helicopter en route to the military hospital in Bethesda, Maryland.

Under such a procedure, doctors block a flood vessel in order to stop blood flow to a specific area and stop a patient from bleeding.

'This morning, First Lady Melania Trump underwent an embolization procedure to treat a benign kidney condition,' according to a statement from her communications director, Stephanie Grisham.

President Donald trump departs from the South Lawn of the White House on May 14, 2018, as he travels to Walter Reed National Military Medical Center in Bethesda, Maryland

Trump tweeted about his visit to see the first lady en route

'The procedure was successful and there were no complications. Mrs. Trump is at Walter Reed National Military Medical Center and will likely remain there for the duration of the week,' her communications director Stephanie Grisham said in the statement.

'The First Lady looks forward to a full recovery so she can continue her work on behalf of children everywhere,' she said, in reference to her recently launched campaign.

The first lady is 48 years old.

The statement was released after the surgery was completed.

A senior administration official told ABC News Trump spoke to his wife before the procedure and talked to her doctor afterward.

Melania Trump unveiled her campaign to try to help children last week

First lady Melania Trump (L) arrives in the East Room to deliver remarks during the White House Opioid Summit March 1, 2018 in Washington, DC

First lady Melania Trump and her son Barron Trump look at the Wisconsin-grown Christmas Tree at the North Portico as it makes its way the Blue Room for display at the White House in Washington, DC on Monday, Nov. 20, 2017

Walter Reed National Military Medical Center is seen after US President Donald Trump arrived for his annual physical in Bethesda, Maryland, January 12, 2018

President Donald Trump arrives on Marine One at Walter Reed National Military Medical Center in Bethesda, Md., Monday, May 14, 2018

President Donald J. Trump arrives aboard Marine One at Walter Reed National Military Medical Center in Bethesda, Maryland, USA, 14 May 2018, to visit US first lady Melania Trump after she had kidney surgery

EXPLAINED: THE KIDNEY EMBOLIZATION SURGERY MELANIA TRUMP UNDERWENT by Natalie Rahhal, health correspondent, and Mia de Graaf, health editor A kidney embolization is a simple procedure done to intentionally block off a blood vessel in the kidney. 'Embolization is a minimally invasive procedure to stop blood flow to parts of an organ (in this case kidney),' Dr Jamin Brahmbhatt, a urologist at Orlando Health, explains. 'It can be used to treat malignant and benign lesions.' WHY IS IT DONE? An embolization is often used as a first-line treatment for any kind of gastrointestinal bleeding, but it can also be preventative. It can be performed on any organ that has a growth or blood vessel clump. There are typically two scenarios for performing a kidney embolization: Preventative: to cut off a tumor's blood supply and shrink, or control a cyst it before it can rupture Emergency: to stem bleeding of a ruptured cyst on the organ There are three things on which kidney embolizations are peformed: To shrink a cancerous tumor by cutting off the blood supply To shrink a benign cyst (i.e. a angiomyolipoma) by cutting the blood supply To fix an arterial vessel malformation (a clump of blood vessels) Angiomyolipomas are benign growths. They disproportionately affect women. Eighty percent of them are spontaneous, while 20 percent of them are genetic Melania Trump's operation was reportedly for a 'benign' kidney condition. Dr Brahmbhatt believes it was like an angiomyolipoma. These growths disproportionately affect women (four times more than men), and 80 percent of them are spontaneous (compared to 20 percent which are genetic). Surgery is only recommended if it grows too big. 'If they're under four centimeters, we just monitor it,' Dr Brahmbhatt explained. 'But if it goes over four centimeters, the risk of it rupturing goes up way high, so that's when we suggest treatment.' HOW IS IT DONE? Typically, a patient is given sedation and the entire procedure is done through an X-ray view. The doctor makes a small incision near the groin, and guides very long, skinny tube, called a catheter, through a blood vessel toward the kidney. There, an 'agent' or chemical that causes the blood to clot is injected, cutting off the flow of blood to through that particular vessel. The entire procedure commonly takes up to three hours and hospital stays afterwards vary. HOW IS THE RECOVERY? 'After embolization patients often have nausea, vomiting, fever, and pain that could last a few days,' Dr Brahmbhatt said. 'These procedures are fairly low risk but still require close follow-up.' Embolizations are minor operations, with relatively low risks of complications or side effects. In very rare cases, patients may have a bad reaction to the dye used in the procedure. More commonly, some have discomfort or minor bleeding after an embolization, and as such they are monitored over night. Some people develop fever, weakness and nausea, a temporary condition called 'post-embolization syndrome,' that usually subsides within a few days. Advertisement

According to CNN, she is the first first lady to have such a serious operation since Nancy Reagan had a mastectomy in 1987 while her husband was in office.

Dr. Sanjay Gupta spoke about the procedure on CNN as the news first broke. He had been on air already to talk about former Senate Majority Leader Harry Reid's treatment for pancreatic cancer at Johns Hopkins University on Monday.

'[It's] unclear exactly what she had done. An embolization procedure is typically done for cancer, although it's very clear in this statement that this was a benign condition,' said Gupta.

'That's how they've framed it. So it doesn't sound like it's any type of cancer,' he added.

'Sometimes thyroids, or cysts, or something like that, can be treated as well [through embolization],' Gupta said.

The statement from Trump's office did not describe what exactly was being treated on her kidney, whether a cyst or some kind of non-cancerous tumor.

First Lady, Nancy and U.S. President Ronald Reagan, look at flowers received from well-wishers on October 19th, 1987 at the Bethesda Naval Hospital

President and Mrs. Ford return to the President's Suite at the Bethesda Naval Hospital, following the First Lady's breast cancer surgery

The statement did not spell out whether she underwent surgery or merely the procedure, which relies on catheters used to try to stem blood flow.

The news comes just a week after the first lady took on a high-profile role by announcing the initiatives she would carry on in her post. She said she wanted to focus on children's health, opioid abuse, and preventing bullying online.

A kidney embolization is a simple procedure done to intentionally block off a blood vessel in the kidney.

The White House offered no updates to the president's schedule even as the first lady's office confirmed he would be visiting soon.

Under an embolization, typically, a patient is given local anesthesia and the entire procedure is done through an X-ray view.

The surgeon makes a small incision near the groin, and guides very long, skinny tube, called a catheter, through a blood vessel toward the kidney.

There, an 'agent' or chemical that causes the blood to clot is injected, cutting off the flow of blood to through that particular vessel.

Kidney embolizations are generally performed when a patient is having kidney bleeding either from trauma, a tumor, or another medical condition.

Melania Trump's operation was reportedly for a 'benign' kidney condition.

The entire procedure takes up to three hours and hospital stays afterwards vary.