Coronary artery ectasia (CAE) is a dilation of the coronary artery lumen. The term ‘ectasia’ refers to diffuse dilation of a coronary artery while focal coronary dilation is called a ‘coronary aneurysm. The definition of coronary artery ectasia is a dilatation exceeding more than one-third of the coronary artery length with the diameter of the dilated segment measuring more than 1.5 times the diameter of a normal adjacent segment. Coronary artery ectasia is well recognized, but uncommon findings encountered during diagnostic coronary angiography. The classification of coronary artery ectasia subdivides into four groups:
The etiology of coronary artery ectasia can be enigmatic. Atherosclerosis lays claim to the principal etiologic cause responsible for greater than 50% of cases in adults, while Kawasaki disease is the most common cause in children and young adults. The histology of atherosclerosis and ectasia are comparable.
Rarely coronary artery ectasia could be genetic; among acquired etiologies; atherosclerosis, Kawasaki disease, mycotic or septic emboli, Marfan syndrome, arteritis from polyarteritis nodosa, Takayasu's disease or systemic lupus erythematosus are prominent. Coronary artery ectasia secondary to iatrogenic causes includes secondary to PTCA, stents, directional coronary atherectomy.
Some of the risk factors for coronary ectasia include the following:
The incidence varies between 0.3 and 4.9%. The CASS registry found coronary artery ectasia in 4.9% of coronary angiograms. Coronary artery ectasia classifies as small (vessel size under 5 mm), medium (vessels size 5 to 8 mm) and giant (vessel size over 8 mm). Based on location most common location is in the right coronary artery (68%), proximal left anterior descending (60%) and left circumflex (50%).
Based on shape, coronary artery ectasia can be divided into "saccular," when the transverse diameter is larger than the longitudinal diameter or "fusiform" when the longitudinal diameter is larger than the transverse diameter.
The exact pathophysiology of coronary artery ectasia is unknown. CAE is an anatomical variant or a clinical constellation of coronary artery disease because it may present with myocardial ischemia or coronary syndrome. The mechanism of luminal dilation in some atherosclerotic vessels is ambiguous; atherosclerosis typically causes narrowing of the vessel lumen. Due to the arterial remodeling, there is an expansion of the medial and external elastic membrane of the blood vessel. This proposed methodology of arterial remodeling may be operative in the case of coronary artery ectasia. Intravascular ultrasound reveals that arterial remodeling can be bidirectional depending upon expansion or contraction of the external elastic membrane. Coronary artery ectasia is believed to be exaggerated expansive remodeling of the external elastic membrane resulting in luminal expansion.
Enzymatic degradation of the extracellular matrix by matrix metalloproteinases (MMP) and other lytic enzymes and thinning of the tunica media associated with severe chronic inflammation is considered the principal pathogenesis of the expansive remodeling. CAE is also related to apical hypertrophic cardiomyopathy with high wall tension. In addition to that, iatrogenic mechanisms, e.g., percutaneous coronary interventions including balloon angioplasty, stent placement, and atherectomy can lead to the formation of aneurysms or ectasias. The mechanism is felt to be the injury of the media of the blood vessel.
Histology usually shows it thickened fibrotic intima with lipid deposition. The internal elastic laminal layer usually suffers disruption leading to the reduction in medial elastic tissue. This loss of elastic tissue is the primary cause along with chronic vascular inflammation leading to ectasia.
The symptoms of coronary artery ectasia may be associated with concomitant coronary disease, Kawasaki disease, or connective tissue disease. Most patients are asymptomatic. Patients with CAE may present with angina post-stress tests and acute coronary syndrome. Diminished coronary flow speed or stagnancy of blood flow may cause exercise-induced angina without coexistent stenotic coronary artery disease. Formation of intracoronary thrombus or dissipation leading to distal emboli may be the trigger of the acute coronary syndrome, which is hastened by stagnant flow in the ecstatic coronary segment. The hypothesis is that coronary artery ectasia is predisposed to vasospasm, which may elicit angina or acute coronary syndrome. In people less than 50 years old, CAE should raise concern for connective tissue disorders and vasculitides.
Coronary angiography is the gold standard in diagnosing coronary artery ectasia. Intravascular ultrasound (IVUS) is critical to the evaluation of luminal characteristics and pathologies. Distortions in flow and washout are common in CAE and are related to the severity of ectasia. Signs of stagnant flow include delayed antegrade contrast filling, segmental backflow, and stasis in the ectatic coronary segment.
Other investigative techniques include MRA and coronary CTA. For follow up of patients, MRA is the preferred modality.
Management of coronary artery ectasia is fraught with uncertainty because the rarity of CAE prevents large randomized trials comparing different treatment approaches. When CAD coexists intense primary and secondary risk factor modifications are mandatory. Management of isolated coronary artery ectasia in a case with angina or myocardial ischemia includes ASA, statin, and anti-ischemic medications. Acute coronary syndromes associated with CAE may require thrombolysis, heparin administration, and glycoprotein IIb/IIIa receptor inhibitors. Thrombus aspiration may be necessary during primary PCI. Percutaneous and surgical interventions are often necessary for patients with CAE and stenotic lesions where angina persists despite maximal medical therapy. Optimal stent sizing to prevent misplacement, and embolization of stents. Many authors recommend chronic anticoagulation - however; no randomized trial demonstrates its benefit in CAE. The anticipated benefit must counterbalance against the risk of hemorrhage.
Surgery is rarely done but is sometimes a necessity in patients who have recurring complications. The surgery involves ligation of the proximal and distal segment of the ectatic vessel and replacing it with a bypass graft. There should be no attempt to repair the ectatic vessel as the results are poor.
The prognosis for coronary artery ectasia is directly related to the severity of concomitant coronary artery disease. Coronary artery ectasia with underlying coronary artery disease is a dangerous combination with an increased potential for adverse cardiac events. Isolated CAE still carries the risk of myocardial ischemia and infarction. Type 1 and Type CAE carry a higher risk than Type 3 and Type 4 CAE. No reported data shows a relationship between the diameter of an artery and outcome.
In complicated cases involving multiple coronary arteries or left main disease; a multi-disciplinary team approach is preferred that includes interventional cardiologist, cardiac surgeon, cardiac intensivist, cardiac catheterization, and ICU and cardiovascular specialty trained nurses, and radiologist to devise a treatment plan to reduced complications and improve outcomes. [Level V]
The overall management is similar to a patient with coronary artery disease. However, because of a lack of long term studies, the ideal management of this disorder remains unknown.
|||Mavrogeni S, Coronary artery ectasia: from diagnosis to treatment. Hellenic journal of cardiology : HJC = Hellenike kardiologike epitheorese. 2010 Mar-Apr [PubMed PMID: 20378518]|
|||Zeina AR,Sharif D,Blinder J,Rosenschein U,Barmeir E, Noninvasive assessment of coronary artery ectasia using multidetector computed tomography. Coronary artery disease. 2007 May [PubMed PMID: 17429290]|
|||Díaz-Zamudio M,Bacilio-Pérez U,Herrera-Zarza MC,Meave-González A,Alexanderson-Rosas E,Zambrana-Balta GF,Kimura-Hayama ET, Coronary artery aneurysms and ectasia: role of coronary CT angiography. Radiographics : a review publication of the Radiological Society of North America, Inc. 2009 Nov [PubMed PMID: 19926755]|
|||Swaye PS,Fisher LD,Litwin P,Vignola PA,Judkins MP,Kemp HG,Mudd JG,Gosselin AJ, Aneurysmal coronary artery disease. Circulation. 1983 Jan [PubMed PMID: 6847792]|
|||Antoniadis AP,Chatzizisis YS,Giannoglou GD, Pathogenetic mechanisms of coronary ectasia. International journal of cardiology. 2008 Nov 28 [PubMed PMID: 18694609]|
|||Manginas A,Cokkinos DV, Coronary artery ectasias: imaging, functional assessment and clinical implications. European heart journal. 2006 May [PubMed PMID: 16415301]|
|||Sayin T,Döven O,Berkalp B,Akyürek O,Güleç S,Oral D, Exercise-induced myocardial ischemia in patients with coronary artery ectasia without obstructive coronary artery disease. International journal of cardiology. 2001 Apr [PubMed PMID: 11334658]|
|||Zografos TA,Korovesis S,Giazitzoglou E,Kokladi M,Venetsanakos I,Paxinos G,Fragakis N,Katritsis DG, Clinical and angiographic characteristics of patients with coronary artery ectasia. International journal of cardiology. 2013 Aug 20 [PubMed PMID: 22572634]|
|||Turhan H,Yetkin E, What is the plausible strategy for the management of patients with isolated coronary artery ectasia and myocardial ischemia? International journal of cardiology. 2007 Apr 25 [PubMed PMID: 16893580]|
|||Levine GN,Bates ER,Blankenship JC,Bailey SR,Bittl JA,Cercek B,Chambers CE,Ellis SG,Guyton RA,Hollenberg SM,Khot UN,Lange RA,Mauri L,Mehran R,Moussa ID,Mukherjee D,Nallamothu BK,Ting HH, 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. Circulation. 2011 Dec 6 [PubMed PMID: 22064601]|
|||Gulec S,Atmaca Y,Kilickap M,Akyürek O,Aras O,Oral D, Angiographic assessment of myocardial perfusion in patients with isolated coronary artery ectasia. The American journal of cardiology. 2003 Apr 15 [PubMed PMID: 12686347]|