T

he hallmark of COVID-19 is respiratory symptoms, but doctors now know that the disease can cause wide-ranging problems throughout the body.

That includes the vascular system, the network of vessels that carries blood to tissues and vital organs. Coronavirus patients who need hospital care have a propensity to develop blood clots that can lead to serious blockages, such as deep vein thrombosis, a pulmonary embolism and stroke.

Researchers are still parsing the biological underpinnings of COVID-19. Dr. Boulos Toursarkissian, a vascular surgeon and endovascular specialist affiliated with Peripheral Vascular Associates in San Antonio, explained several theories on how and why the disease affects the blood vessels.

This interview has been edited for length and clarity.

Can you give an overview of what we know about how COVID-19 affects