Garry Choy, MD1; Brian Ghoshhajra, MD, MBA1; Terrance T. Healey, MD2; Carlos A. Rojas, MD1; Efren Flores, MD1; Axel Scherer, MD3; Sung Han Kim, MD4; Suhny Abbara, MD1

Coronary Aneurysms: What Every Radiologist Needs to Know1Department of raDiology, MASSACHUSETTS GENERAL HOSPITAL • 1,4HARVARD MEDICAL SCHOOL • 4mt. auburn Hospital • 2Department of raDiology, rHoDe islanD Hospital, brown meDical scHool • 3 institute of Diagnostic raDiology, HeinricH-Heine university

REFEREnCES1. Abbara, S, Walker TG. Diagnostic Imaging: Cardiovascular. Amirsys. 2008.2. Baker AL, Newburger JW. Kawasaki disease. Circulation 2008;118: e110-2.3. European Coronary Surgery Study Group. Prospective randomized study of coronary artery bypass surgery in stable angina pectoris. Lancet. 1980; 2:491–495.4. Ghanta RK, Paul S, Couper GD. Successful revascularization of multiple coronary artery aneurysms using a combination of surgical strategies. Ann Thorac Surg. 2007; 84: e10–e11.5. Harandi S, Johnston SB, Wood RE, et al. Operative therapy of coronary arterial aneurysm. Am J Cardiol. 1999; 83:1290–1293.6. Hartnell GG, Parnell BM, Pridie RB. Coronary artery ectasia: its prevalence and clinical significance in 4993 patients. Br Heart J. 1985; 54:392–395.

7. Murthy PA, Mohammed TL, Read K, Gilkeson RC, White CS. MDCT of coronary artery aneurysms. AJR Am J Roentgenol 2005;184:S19-20. 8. Takaki MT, Dubinsky TJ, Warren BH, Mitsumori L, Shuman WP. Nonatherosclerotic cardiovascular findings on MDCT coronary angiography: a selection of abnormalities. AJR Am J Roentgenol 2008;190:934-46. 9. Satran A, Bart BA, Henry CR, Murad MB, Talukdar S, Satran D, Henry TD. Increased prevalence of coronary artery aneurysms among cocaine users. Circulation. 2005 May 17;111(19):2424-9. Epub 2005 May 9.10. ECG-gated Cardiac CT Evaluation of a Saphenous Vein Graft Aneurysm Pre- and Post- Percutaneous Intervention, Rojas CA, MD, El-Sherief A., MD, Choy G., MD, Medina-Zulaga H., MD, Inglessis I., MD, Abbara S., MD and Mamuya W., MD, Cardiovascular Images, Massachusetts General Hospital, 2009 http://www.mgh-cardiovascimages.org/

PURPOSE To review the variety and range of coronary artery and bypass graft aneurysms To discuss the findings and diagnostic criteria To explain the pathological processes

What is a coronary artery aneurysm?

DEfinitiOn Coronary artery diameter >1.5X normal adjacent seg diameter

tyPES •Focalordiffuse •Fusiformorsaccular

CliniCal imPliCatiOnS •Oftenasymptomaticbutpatientscanpresentwith angina, myocardial infarction, or sudden death •Otheradverseeventsincludethrombosis,thromboembolism, AV fistulae, vasospasm, and rupture •Incidentalfindingoncoronaryangiograms

PathOPhySiOlOgy Thought to be similar to that for aneurysms of larger vessels, with destruction of the vessel media resulting in increased wall stress and subsequent dilation

EPiDEmiOlOgy •AtherosclerosismostcommoncauseinUSA •KawasakiDiseasemostcommoncauseglobally •Basedonseveralangiographicstudies, incidence of coronary artery aneurysms ranges from 0.3% to 5.3% of the population •Incidencehasbeenreportedinupto1.8%inan angiographic study [ref: Nichols] •Rightcoronaryarteryismostcommonlyaffected (40–87% of aneurysms), followed by left circumflex or left anterior descending artery, depending on the study [ref: Villines] •Three-vesselorleftmaininvolvementisrare

BESt imaging tOOl •CoronaryCTAorCoronaryangiography •Goalistoestablishdiagnosisandtoprovideadditional information about size, shape, location, and number of existing anomalies •Imagingiscriticalinfollow-uptoensurestabilityofaneurysms

tREatmEntS •Anticoagulants,antiplatelettherapy,bypass,coveredstents •Treatment options consist of surgical, percutaneous, and medical approaches •At mean of 3.2 years follow-up, mortality rates after surgery and medical management were 7.7% and 13% where follow-up was available), respectively •Similar mortality rates at 5 yrs were reported in European Coronary Surgery Study of patients treated surgically or medically •Operative therapy includes CABG, aneurysm ligation, resection, or marsupialization with interposition graft •Percutaneous treatment is a newer option and includes stenting and coiling

morphology of coronary artery aneurysms

Fusiformorsacculardilatation

Can be associated with thrombosis

Atherosclerotic Disease

Findings Fig 1A - B: Atherosclerotic aneurysmal dilatation of the distal left main to 9 mm, with continuation of aneurysm into the proximal LAD

Fig 2A - B: Massive atherosclerotic left main to LAD coronary aneurysminadifferentpatient

Fig 3A, B, C: Saccular aneurysm in setting of Atherosclerotic Disease in proximal LAD

Teaching Points - Atherosclerotic Disease

MostcommoncauseinUSA

Male-predominant

Pathophysiology Atherosclerotic related inflammation-mediated thinning or destruction of media; increased MMP (matrix metalloproteinase) activity resulting in proteolysis of extracellular matrix proteins have been implicated in atherosclerosis

Symptoms and complications related to concurrent degree of CAD or obstructive coronary disease

Teaching Points – Cocaine

Cocaine mediated aneurysms have a similar appearance as aneurysms related to atherosclerotic diseaseCoronary aneurysms and occur between 0.2% to 5.3% of patients referred for angiographyT. Henry, et al found that among cocaine users, up to 30% in a study of 112 patients had coronary artery aneurysmsAverage age was 44 years old and predominantly malePotential pathophysiological mechanism may be tied to chemically-mediated severe local episodic hypertension and vasoconstriction with direct endothelial damage predisposing to aneurysm formationSaccular or fusiform morphology of aneurysms not unlike in appearance with aneurysms found in atherosclerotic disease

EtiOlOgiES Of COROnaRy anEURySmS Atherosclerotic Disease (MostcommoncauseinUSA) Kawasaki Disease (Most common cause worldwide) Connective Tissue Disease (SLE, Marfan, Behcet’s Disease)

Pseudoaneurysms Saphenous Vein Graft Aneurysm Post-Traumatic Pseudoaneurysm Infection Coronary Fistulas Cocaine Use

Connective Tissue Disease - Marfan Syndrome Findings

Fig 16A, B, C, D: Patient with both sinus of Valsalva aneurysm and fusiform aneurysm involving distal left main, proximal LAD, proximal LCX in setting of Marfan Syndrome. Only minimal atherosclerotic disease with tiny focus calcification seen in distal left main

Teaching Points – Connective Tissue Disease

Pathophysiology LinkedtoexcessTGF-betaproduction(proteinthatishomologouswithfamilyofproteinsinmicrofibrilsinelastinfibers)

Examples of connective tissue diseases associated with coronary aneurysms: Marfan Syndrome: Mutation in gene encoding fibrillin; cystic medial degeneration common feature of aneurysms Behcet’s:Formofvasculitisassociatedwithsystemicvascularinflammation;patientsalsopresentwithoralulcers, genital ulcers, skill lesions, uveitis

Kawasaki Disease Findings

Fig 4A, B, C, D:FusiformdilatationoftheproximalRCAinpatientwithminimalatherosclerosisand history of Kawasaki Disease

Fig 5A, B, C: Multiple fusiform aneurysms in proximal RCA and LAD. Calcification possibly related to chronic nature of thrombosis in setting of Kawasaki Disease

Fig 6: Partially thrombosed RCA aneurysm in patient with Kawasaki Disease

Fig 7A - B: Multiple partially calcified fusiform aneurysms in LAD and diagonal branch in patient with Kawasaki Disease.

Teaching Points – Kawasaki Disease

Kawasaki Disease - mucocutaneous lymph node syndrome; self limited systemic vasculitis of childhoodaffectingmultiplesystemsincludingcoronaryarteries

Epidemiology MainlyAsianpopulation,50/100,000childreninJapan(10XhigherincidencethanUS)

Pathophysiology Generalized systemic vasculitis involving large, medium sized arteries associated with aneurysm and thrombosis

Cardiac findings in Kawasaki Disease include myocarditis, coronary aneurysms, or arrhythmias

Kawasaki Disease patients at risk for thrombosis due to increased platelets (thrombosis often found in aneurysms); aneurysms may not be discovered until adulthood

Treatment Antiplatelet or anticoagulation therapy

Post-Traumatic Pseudoaneurysm

Findings Fig 8: This patient underwent balloon angioplasty and stenting of the left main to LAD and circumflex after acuteocclusion.Follow-upcatheterization2weekslaterforrecurrentchestpaindemonstratesapost- traumaticpseudoaneurysmattheangioplastyandstentsite.Follow-upCTA3monthslaterdemonstrates near-complete resolution

Fig 9:Pseudoaneurysmoftheleftmaininadifferentpatientafterballoonangioplasty

Fig 10: Catheter angiogram demonstrates an aneurysmal saphenous vein graft

Fig 11:UnenhancedaxialCTdemonstratesmuralthrombusintheaneurysm

Fig 12A, B, C, D: Enhanced CTA demonstrates the lumen and the true diameter of the aneurysm Note the dilated apical aneurysm and calcified papillary muscle, confirming a remote MI

Figure 13A: Pre-intervention axial multiplanar reformation (MPR) image demonstrating a large SVG aneurysm with associated thrombus within the aneurysmFigure 13B: Pre-intervention coronal maximum intensity projection (MIP) image demonstrating a large SVG-PLV aneurysmFigure 13C: Post-intervention axial MPR image demonstrating successful stenting and exclusion of the SVG-PLV aneurysmFigure 13D: Post-intervention coronal MIP image demonstrating successful exclusion of the SVG-PLV aneurysm, without evidence of an endoleak

Fig 14A, B, C: Extremely large Saphenous Vein Graft Pseudoaneurysm with associated median sternotomy dehiscence

Fig 15A, B, C: Mycotic Pseudoaneurysm – Infection/Traumatic Images demonstrate a patient with inflammatory pericarditis from group B streptococcus infection. 6 weeks prior, pericardiocentesis revealed Group-C-Streptococci. No history of childhood illness nor connective tissue disease. CTA shows focal saccular aneurysm of the RCA. Rim-enhancing pericardial fluid collection along the left lateral border of the heartFig 15D: Double-Oblique Coronal. Arterial-phase gated CTA demonstrates a 2-3 cm collection of contrast in continuity with the distal RCA. Narrow connection to parent vesselFig 15E: Catheter Coronary Angiography. Coronary angiography demonstrates collection of contrast in distal RCA confirming CTA findingFig 15F: Post-Stent CTA (with residual contrast in excluded sac). Because of the tenuous condition of the patient, a covered stent was placed in the RCA. In order to secure a landing zone, the PDA was sacrificed. ThepatientsufferedasmallinferiorwallMI

Teaching Points - Pseudoaneurysm

Most commonly, pseudoaneurysms are post-traumatic in nature related to intervention or surgery such as CABG, cardiac angiography in setting of stent placement or angioplasty or pericardiocentesis

Infection may also result in pseudoaneurysm

Fig 01A Fig 01B

Fig 02A Fig 02B

Fig 03A Fig 03B

Fig 03C

Fig 04A Fig 04B

Fig 04C Fig 04D

Fig 05A

Coronary FistulasFindingsFig 17A - B: Anterior and inferior-posterior volume rendered images demonstrate an enlarged, tortuous RCA, with the PLVbranchconnectingtothecoronarysinus(arrow).Flow therefore shunts from the high-pressure coronary artery to the low-pressure coronary sinus

Fig 18A - B: Coronary fistula of left circumflex artery (LCX) to thecoronarysinus.TheLCX(redarrow)isdiffuselyectatic with a large focal aneurysm (yellow arrow) immediately proximal to anastamosis with coronary sinus (orange arrow)

Teaching Points – Coronary FistulasConsidercoronaryfistulaasadifferentialconsideration when aneurysmal dilatation of coronary artery is seen

Abnormal direct connection between coronary artery and a cardiac chamber

Etiology Usuallycongenitalinnature Latrogenic after biopsy or intervention Trauma

Connects high pressure system to low pressure system

Best imaging findings Tortuous and enhancing epicardial arteries

Markedly enlarged and tortuous coronary arteries; aneurysmal dilatation immediately proximal to drainage site

Fig 05B

Fig 05C Fig 06

Fig 07A

Fig 07B

Fig 08 Fig 09

Fig 10 Fig 11

Fig 12A Fig 12B Fig 12C Fig 12D

Fig 14A Fig 14B Fig 14C

Fig 15A Fig 15B Fig 15C Fig 15D Fig 15E Fig 15F

Fig 16A Fig 16B

Fig 16C Fig 16D

Fig 17A Fig 17B Fig 18A Fig 18B

Fig 13A Fig 13B Fig 13C Fig 13D