Photo by Rhoda Baer
Therapist preparing patient to receive radiation
VIENNA, AUSTRIA—Hodgkin lymphoma (HL) survivors who received chest irradiation should be screened for coronary artery disease (CAD), according to researchers.
The team evaluated HL survivors who underwent mediastinal irradiation 20 years prior to study initiation.
These individuals were more likely to have CAD and to have more severe CAD than matched control subjects.
The researchers presented these findings at ICNC 2017, the International Conference on Nuclear Cardiology and Cardiac CT (abstract P118).
“Patients with Hodgkin lymphoma receive high-dose mediastinal irradiation at a young age as part of their treatment,” said Alexander van Rosendael, MD, of Leiden University Medical Centre in the Netherlands.
“There is an ongoing debate about whether to screen patients who get chest irradiation for coronary artery disease.”
Therefore, Dr van Rosendael and his colleagues assessed the extent, severity, and location of CAD in HL survivors who had received chest irradiation.
The study included 79 patients who had been free of HL for at least 10 years and had received mediastinal irradiation 20 years ago, plus 273 control subjects without HL or irradiation.
CAD was assessed using coronary computed tomography angiography (CTA). To assess differences in CAD between patients and controls, they were matched in a 1:3 fashion by age, gender, diabetes, hypertension, hypercholesterolemia, family history of CAD, and smoking status.
Patients were 45 years old, on average, and the presence of cardiovascular risk factors was low overall.
Forty-two percent of patients had no atherosclerosis on coronary CTA, compared to 64% of controls (P<0.001).
Regarding the extent and severity of CAD, HL patients had significantly more multi-vessel CAD than controls. Ten percent of patients had 2-vessel disease, and 24% had 3-vessel disease, compared to 6% and 9% of controls, respectively (P=0.001).
The segment involvement score (which measures overall coronary plaque distribution) and the segment stenosis score (which measures overall coronary plaque extent and severity) were significantly higher for patients than for controls (P<0.001 and P=0.034, respectively).
Regarding the location of CAD, patients had significantly more coronary plaques in the left main (17% vs 6%, P=0.004), proximal left anterior descending (30% vs 16%, P=0.004), proximal right coronary artery (25% vs 10%, P<0.001), and proximal left circumflex (14% vs 6%, P=0.022), but not in non-proximal coronary segments.
Patients had about a 4-fold higher risk of proximal plaque and about 3-fold higher risk of proximal obstructive stenosis compared to controls (odds ratios, 4.1 and 2.9, respectively; P values, <0.001 and 0.025, respectively).
“Hodgkin patients who have chest irradiation have much more CAD than people of the same age who did not have irradiation,” Dr van Rosendael said.
“The CAD occurred at a young age—patients were 45 years old, on average—and was probably caused by the irradiation. The CTA was done about 20 years after chest irradiation, so there was time for CAD to develop.”
“What was remarkable was that irradiated patients had all the features of high-risk CAD, including high stenosis severity, proximal location, and extensive disease. We know that the proximal location of the disease is much riskier, and this may explain why Hodgkin patients have such poor cardiovascular outcomes when they get older.”
Dr van Rosendael explained that irradiation of the chest can cause inflammation of the coronary arteries, making patients more vulnerable to developing CAD. But it is not known why the CAD in irradiated patients tends to be proximally located.
He said the finding of more, and more severe, CAD in irradiated patients supports the argument for screening.
“When you see CAD in patients who received chest irradiation, it is high-risk CAD,” he said. “Such patients should be screened at regular intervals after irradiation so that CAD can be spotted early and early treatment can be initiated.”
“These patients are around 45 years old, and they are almost all asymptomatic. If you see a severe left main stenosis by screening with CTA (which occurred in 4%), then you can start statin therapy and perform revascularization, which may improve outcome. We know such treatment reduces the risk of events in non-irradiated patients, so it seems likely that it would benefit Hodgkin patients.”
