My middle-aged patient with a history of mediastinal irradiation for Hodgkin’s lymphoma in his 20s now has moderate aortic regurgitation. Could his valvular disease be related to the radiation he received over 20 years ago?

Absolutely! Mediastinal irradiation is associated with several cardiac complications, including coronary artery disease, pericarditis, systolic or diastolic dysfunction and valvular disease. Valvular disease may occur in 2-37% of patients after mediastinal irradiation, is dose-dependent, and generally does not manifest until 10-20 years after the radiation exposure.1 Since mediastinal irradiation is common in young adults diagnosed with Hodgkin’s lymphoma, these complications may be seen in early middle-age or later.

Valvular retraction is usually the first radiation-induced valvular change, and most commonly leads to mitral and aortic valve regurgitation.2 This retraction tends to occur within 10 years of the radiation therapy, followed by fibrosis and calcification of the valves after 20 years.

Although the pathophysiology of radiation-induced valvular disease is not entirely understood, activation of fibrogenic growth factors (eg, tissue growth factor β1 and myofibroblasts) which promote the synthesis of collagen has been postulated.1 Additionally, irradiation of aortic interstitial cells has been shown to cause transformation to an osteogenic phenotype that produces bone morphogenic protein 2, osteopontin and alkaline phosphatase, all important factors in bone formation and possibly valvular calcification.3

Since radiation-induced heart disease is the most common cause of non-malignant morbidity and mortality in patients who have undergone mediastinal irradiation, some have recommended screening of asymptomatic patients for valvular disease every 5 years by echocardiography beginning 10 years after radiation therapy. 2  If an abnormality is found, the screening frequency should increase to every 2-3  years,  if the valvular abnormality is mild, or annually if the abnormality is moderate. For severe valvular abnormalities, the patients should be considered for valve replacement.

References

    1. Gujral DM, Lloyd G, Bhattacharyya S. Radiation-induced valvular heart disease. Heart 2016;102:269–276. https://heart.bmj.com/content/heartjnl/102/4/269.full.pdf
    2. Cuomo JR, Sharma GK, Conger PD, Weintraub NL. Novel concepts in radiation-induced cardiovascular disease. World J Cardiol. 2016; 8 (9):504-519. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039353/
    3. Nadlonek NA, Weyant MJ, Yu JA, et al. Radiation induces osteogenesis in human aortic valve interstitial cells. J Thorac Cardiovasc Surg 2012;144:1466–70. doi:10.1016/j.jtcvs.2012.08.041 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665422/

Contributed by Rachel Wallwork, MD, Mass General Hospital, Boston, MA

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My middle-aged patient with a history of mediastinal irradiation for Hodgkin’s lymphoma in his 20s now has moderate aortic regurgitation. Could his valvular disease be related to the radiation he received over 20 years ago?

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