Radiation induced coronary artery disease – RICAD

Radiation induced coronary artery disease – RICAD

Radiation induced coronary artery disease (RICAD) is an important long term sequelae of radiotherapy to the chest region. The most common conditions associated with RICAD are breast cancer and Hodgkin’s lymphoma. The risk is higher in Hodgkin’s lymphoma because they receive a higher dose of radiotherapy [1]. It may be noted that radiation is used in the treatment of about 50% of cancers [2]. Hence the importance of RICAD.

Radiation causes vascular endothelial injury. It initiates and accelerates atherosclerosis. Proinflammatory cytokines were increased in the blood of long term survivors of atomic bomb, suggesting a systemic inflammatory state [3].

Even though RICAD is in general more common in older patients, younger patients have also been reported [4]. One 30 year old male with radiation 15 years prior had total occlusion of proximal left anterior descending coronary artery and 90% stenosis of proximal right coronary artery. Emergency angioplasty with stenting was done. Another 31 year old female with radiation 8 years prior had left ventricular dysfunction (ejection fraction 35%) and 99% proximal left main coronary artery stenosis. She underwent successful coronary artery bypass grafting. A third person was a 25 year old male who had radiation for spinal tumour 9 years prior. He had left ventricular dysfunction, moderate aortic regurgitation, severe calcification of aortic and mitral valves and 99% left main coronary artery stenosis. But he did not survive after coronary artery bypass grafting [4].

Latency may be long in RICAD, with patients presenting decades after radiation exposure. Manifestations range from asymptomatic perfusion defects to triple vessel disease and even sudden death. Though involvement of the coronaries may be diffuse a preference for proximal involvement is often noted. Inflammatory plaque with high collagen and fibrin content is seen pathologically. Partial prevention may be achieved by aggressive management of conventional coronary risk factors, best initiated prior to radiation therapy. Special investigations considered are stress echocardiography, myocardial perfusion imaging and computed tomographic (CT) coronary angiography. Higher rates of graft failure, perioperative complications and all-cause mortality are associated with coronary artery bypass grafting in RICAD. Coronary angioplasty with drug eluting stents may be the preferred option in the management of RICAD in most cases [5].

References

1. Brown KN, Richards JR. Radiation Induced Coronary Artery Disease. StatPearls [Internet].
2. Delaney G, Jacob S, Featherstone C, Barton M. The role of radiotherapy in cancer treatment: estimating optimal utilization from a review of evidence-based clinical guidelines. Cancer. 2005 Sep 15;104(6):1129-37.
3. Venkatesulu BP, Mahadevan LS, Aliru ML, Yang X, Bodd MH, Singh PK, Yusuf SW, Abe JI, Krishnan S. Radiation-Induced Endothelial Vascular Injury: A Review of Possible Mechanisms. JACC Basic Transl Sci. 2018 Aug;3(4):563-572.
4. Ruiz CR, Mesa-Pabón M, Soto K, Román JH, López-Candales A. Radiation-Induced Coronary Artery Disease in Young Patients. Heart Views. 2018 Jan-Mar;19(1):23-26.
5. Cuomo JR, Javaheri SP, Sharma GK, Kapoor D, Berman AE, Weintraub NL. How to prevent and manage radiation-induced coronary artery disease. Heart. 2018 Oct;104(20):1647-1653. doi: 10.1136/heartjnl-2017-312123. Epub 2018 May 15. PMID: 29764968; PMCID: PMC6381836.