Is it possible that the heart cause edema

The short version: heart failure is one of the most common causes of edema, and the evidence here confirms that link clearly.

When the heart pumps weakly, blood backs up in the veins. That raises pressure in the capillaries, pushing fluid out of the vessels and into the tissues. The legs swell first because gravity pulls the fluid down. The evidence shows this directly: in a study of 12,778 critically ill patients, those with peripheral edema had a 30% higher risk of acute kidney injury [1]. That study also found that every 1 cmH2O rise in central venous pressure (the pressure in the big veins returning blood to the heart) increased kidney injury risk by 2% [1]. Higher venous pressure is the mechanism: the failing heart cannot move blood forward, so pressure builds backward and fluid leaks out.

The evidence also shows that fluid retention predicts heart failure before it is diagnosed. In 30 diabetes patients starting a class of drugs known to cause fluid retention, those who gained more than 2 liters of total body water went on to develop congestive heart failure with edema within four months [2]. The swelling was the warning sign.

Not all edema is from the heart. The evidence also shows that obesity can compress the inferior vena cava (the main vein from the lower body), raising pressure and causing leg swelling even with a normal heart [4]. And certain drug combinations, like the antifungal itraconazole with the blood pressure drug nifedipine, produce a strong signal for both heart failure and peripheral edema in the FDA's adverse event database [3].

My call: yes, heart failure causes edema through backward pressure in the veins. If you have swelling in the legs or face, heart function should be checked. Confidence: high.