CAD after COVID-19 discovered during heart surgery: Case report

The SARS-CoV-2 virus has been identified as a potential trigger of the disease

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Signs of cold agglutinin disease (CAD) — later found to have been triggered by a previous COVID-19 infection — were detected during heart surgery in a man in Turkey, a case study showed. The case adds to several others reporting developing CAD following COVID-19 disease.

Despite being rare, “it seems that we will encounter it more often after the COVID-19 pandemic,” the researchers wrote in the case report, “Incidentally discovered cold hemagglutinins within autologous blood bag and cardioplegia line in a patient with a recent history of COVID-19 undergoing coronary artery surgery,” which was published in the Perfusion.

In CAD, the immune system produces autoantibodies that wrongly target red blood cells. These antibodies — known as cold agglutinins — bind to red blood cells at cold temperatures, causing them to clump together, marking them for destruction.

Red blood cells carry hemoglobin, the protein responsible for transporting oxygen in the blood. These cells’ destruction can lead to weakness and fatigue, along with pain and bruising in the extremities, especially during cold weather or exposure to cold objects.

Since cell counting methods in laboratories can’t count aggregated red blood cells, low counts and a percentage of red blood cells that are incompatible with hemoglobin levels may suggest CAD.

The abnormal immune responses that drive CAD can be triggered by certain infections, such as those caused by the Epstein-Barr virus, which can result in infectious mononucleosis (or mono), and by a pneumonia-causing bacterium called Mycoplasma pneumoniae.

In the past couple years, SARS-CoV-2, the virus that causes COVID-19, has been identified as another potential trigger of CAD in several case reports.

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Developing CAD after SARS-CoV-2 infection

Researchers at the Ankara City Hospital, Turkey, described the case of a 46-year-old man who presented signs of CAD during heart surgery that were later deemed likely related to a previous SARS-CoV-2 infection.

The man had a history of diabetes and high blood pressure. He’d recovered from a SARS-CoV-2 infection a month and a half before going to the hospital’s outpatient clinic for a coronary artery bypass graft (CABG) to treat narrowed or clogged heart arteries.

The procedure involves restoring blood flow and oxygen transport through the heart by creating a new route for blood to flow around the affected artery. The person’s heart is temporarily stopped using chemicals and cold so the surgeon can sew on the grafts, while blood circulation is maintained with a specialized machine.

Before surgery, the electrical activity of the man’s heart and its ability to pump blood were within normal ranges. Blood work showed incompatibilities between hemoglobin levels and the number and proportion of red blood cells. He also had high levels of lactate dehydrogenase, which can be a sign of red blood cell destruction.

The surgery was initiated in the absence of any further warning signs and the man was cooled to a temperature of 32 C (about 89.6 F) and given a cold solution (4 C or 39.2 F) of cardioplegia, a chemical that induces a rapid heart stop, mixed with his blood.

The surgeons noticed red blood cells started clumping together during the infusion, prompting it to be stopped. The blood taken previously from the patient also clumped together and formed air bubbles, becoming unusable. Stopping the man’s heart was achieved through other means and the surgery was completed without any complication.

The physicians later asked the patient about any cold-related symptoms. He reported having aches and bruises on the nose tip, ears, and fingertips when in the cold and that these started after his SARS-CoV-2 infection. The bruising and pain diminished when he got warmer. The researchers said blood work done before his COVID-19 infection was completely normal.

A cold agglutinin test was performed, confirming a CAD diagnosis. The fact that cold-related symptoms and abnormal blood work were reported after COVID-19 suggested the infection was the cause of CAD, the researchers said, noting the man’s case was a “remarkable first case in cardiac surgery that demonstrated the potential of COVID-19 disease causing the development of autoimmune disease.”

They said more detailed examination before surgery is becoming necessary. “Except for deep [low body temperature], the most important problem is seen during cardioplegia administration. Therefore, non-blood cardioplegia can be lifesaving,” they said.