Giant coronary aneurysms exceeding 5 cm in size

Abstract

Giant coronary artery aneurysms (gCAAs) with a diameter exceeding 5 cm are extremely rare. The pathomechanisms and therapeutical measures in such cases have been controversial topics of discussion. Twenty-seven patients with gCAAs exceeding 5 cm in size described in the literature were evaluated. A case with multiple gCAAs at our department was included in the analysis. Apart from atherosclerosis of all coronary arteries, a large (1.5 × 2.5 cm) left anterior descending coronary artery aneurysm (CAA) and a gCAA (10.6 × 9.2 cm) originating from the right coronary artery, the latter causing recurrent myocardial ischaemia with the occlusion of the peripheral right coronary artery and compressing the right cardiac cavities, were the pathological findings in our 43-year old male patient. gCAAs predominantly develop at the proximal right coronary artery. The majority of these aneurysms develop secondary to atherosclerotic lesions in young patients. We performed a successful surgical excision of the right gCAA, tightening of the left anterior descending artery aneurysm and concomitant coronary artery bypass grafting. A pathological examination confirmed advanced atherosclerosis. Microbiological examinations could find no signs of infectious causes. CAAs bear a significant risk of severe complications and have a high risk of mortality. A more aggressive surgical approach should be recommended.

INTRODUCTION

Coronary artery aneurysms (CAAs) are rare, with an incidence of 0.02 to 0.04% in the general population [1]. Considering patients undergoing coronary angiography, the incidence ranges from 1.1 to 4.9% [2, 3]. They are most commonly associated with male gender and hyperlipidaemia [2–5]. The proximal right coronary artery seems to be predominantly altered [2, 3]. About one-fourth of these patients have multiple coronary aneurysms [2]. Giant CAAs (gCAAs) exceeding 5 cm in size are an exception. The pathomechanisms are not well defined, and the therapeutical measures in these patients remain controversial topics of discussion.

METHODS

Cases of gCAAs were sought in the Pubmed and Medline databases. Including our patient, 27 patients with gCAAs exceeding 5 cm in diameter could be detected in the literature (Table 1). Source, gender, age, location of the predominant CAA, further coronary artery pathology, further aneurysm location, underlying disease, cardiac symptoms, therapy and outcome of these patients were analysed. Continuous data were presented as mean (±standard deviation); dichotomous data were expressed as numbers and percentages. Univariate comparisons were tested with Fisher's exact test in 2 × 2 tables. A P-value of <0.05 was considered as statistically significant.

Table 1:

Citations of CAAs exceeding 5 cm in diameter

Author	Citation
Chapman et al.	Br Heart J 1978;40:938–9
Channon et al.	Am J Cardiol 1998;82:1307–8
Suzuki et al.	Heart 1999;81:214–7
Nakaike et al.	Angiology 1999;47:311–4
Westaby et al.	Ann Thorac Surg 1999;68:1401–3
Peterson et al.	Circulation 1999;100:e8–11
von-Rotz et al.	Ann Thorac Surg 2000;69:1568–9
Fistenberg et al.	Ann Thorac Surg 2000;70:1397–8
Anfinsen et al.	Eur J Echocardiogr 2004;5:308–12
Banerjee et al.	Heart 2004;90:e50
Li et al.	J Thorac Cardiovasc Surg 2005;130:817–21
Kumar et al.	Am J Cardiol 2006;98:986–8
Augustin et al.	Lancet 2006;368:386
Kwon et al.	Int J Cardiol 2007;119:e46–7
Ghanta et al.	Ann Thorac Surg 2007;84:e10–11
Blank et al.	Ann Thorac Surg 2007;84:1740–2
Liu et al.	Interact CardioVasc Thorac Surg 2011;12:639–41
Shimamura et al.	J Card Surg 2011;26:48–51
Mora et al.	Wien Klin Wochenschr 2011;123:58–60
Marcy et al.	J Am Coll Cardiol 2011;57:e99

Case report

A previously healthy 43-year old male patient was admitted to our hospital with chest pain and subsequent hypotension. Only a medical history of hypercholesterolemia and a family history positive for myocardial infarction were noticeable. Electrocardiogram revealed a mild ST-elevation in leads II, III and aVF. Slightly elevated troponin I levels of 0.4 ng/ml (0.01–0.1 ng/ml) and an elevated low-density lipoprotein cholesterol of 260 mg/dl (0–130 mg/dl) were the only striking laboratory data. On echocardiography, a mediastinal mass compressing the right atrium with consecutive obstruction of the tricuspid valve was observed. Multisliced computed tomography of the thorax revealed two small aneurysms with a diameter of 1.4 and 1.1 cm proximally of a giant, partially thrombosed right CAA, measuring 10.6 × 9.2 cm, compressing the right atrium subtotally. Additionally, a large aneurysm of the proximal left anterior descending (LAD) coronary measuring 1.5 × 2.5 cm was also noted. Apart from the aneurysmatic alterations of the coronary arteries, a significant arteriosclerosis of all coronary arteries was apparent. Additionally, atherosclerotic alterations were revealed in distal parts of the aorta and iliofemorally. A coronary angiogram confirmed these findings with multiple severe stenoses of the LAD and circumflex coronary along with an LAD aneurysm and an occluded right coronary artery with a thrombosed giant aneurysm (Fig. 1). During the angiography, the patient experienced an episode of relevant hypotension. Myocardial revascularization was indicated due to the pathological findings as well as the myocardial ischaemia of the right coronary artery.

Figure 1:

Occluded right coronary artery with giant partially thrombosed aneurysm.

RESULTS

The giant partially thrombosed right CAA of our patient (Fig. 2) was partially resected, the thrombus was removed and the inflow ligated. The aneurysm of the LAD was tightened, and myocardial revascularization of the LAD with a left internal mammary artery bypass and sequential venous coronary artery bypass grafting to the circumflex and right coronary artery was performed. The patient recovered well from the surgical procedure, had an uneventful postoperative course and was discharged from hospital in a healthy condition.

Figure 2:

Intraoperative image of the thrombosed giant aneurysm of the right coronary artery.

Microbiological examinations were negative for infectious causes. Histopathological findings of specimens taken from the LAD aneurysm and the giant coronary aneurysm of the right coronary artery confirmed a severe calcificating atherosclerosis with marked intimal fibrosis and necrotic vessel wall portions as well as mural inflammatory reactions.

In the analysis of patients with aneurysms exceeding 5 cm in size, the average age was 54.7 ± 16.2 years, and 64% were male patients. The right coronary artery was involved in 89% of the cases with a proximal location in more than 85.7%. Concomitant aneurysms at other coronary sites were found in one-fourth of the cases, and fistulas to cardiac cavities were found in six patients (21.4%). Atherosclerosis of the coronary arteries was detected in more than 60% of the described cases; a congenital pathology was assumed in five patients. Seven of the patients with gCAAs were reported to have had no cardiac symptoms. Surgery for CAA was performed in 19 patients (67.8%); one of these patients died during surgical procedure. One patient was successfully treated by percutaneous transfemoral coronary means. A conservative treatment with antiplatelet or anticoagulant medication was described in five patients. Only one of these patients had an uneventful course, two patients died and no statement of the outcome was given for the remaining two patients. All patients who were not treated died. The data are presented in Table 2.

Table 2:

Pertinent data of patients described with CAA exceeding 5 cm in size

Author	Age	Gender	Location CAA >5 cm	Further coronary pathology	Further aneurysms	Underlying disease	Cardial symptoms	Cardiac therapy	Outcome
Daoud (1963)	77	W	Prox RCA		Aortic	Atherosclerosis	No	No	Died
	51	M	Prox RCA		Aortic	Atherosclerosis	Unspecific	No	Died
Chapman (1978)	63	M	Distal RCA	Fistula to right atrium		Atherosclerosis	Yes	Surgery	Uneventful
Channon (1998)	72	M	Prox RCA	Aneurysm LAD		Atherosclerosis	No	Surgery	Uneventful
Suzuki (1999)	46	W	Prox LAD			Takayasu's arterits	Yes	Conservative	Died
Nakaike (1999)	72	W	Prox RCA			Atherosclerosis	Yes	Conservative	Died
Westaby (1999)	70	M	Prox RCA	Aneurysm LAD		Atherosclerosis	Unspecific	Surgery	Uneventful
	71	M	Prox RCA		Aortic	Atherosclerosis	Yes	Surgery	Uneventful
Peterson (1999)	61	M	Prox RCA	Aneurysm CX		Atherosclerosis	Unspecific	PTC	Uneventful
von-Rotz (2000)	43	M	Distal RCA			?	Yes	Surgery	Uneventful
Firstenberg (2000)	73	W	Prox RCA			Atherosclerosis	Yes	Surgery	Uneventful
Anfinsen (2004)	73	M	Prox RCA			Atherosclerosis	Yes	Conservative	Uneventful
	55	M	Prox RCA			Atherosclerosis	Yes	Conservative	Not stated
Banjeree (2004)	69	M	Prox RCA	Multiple aneurysms LAD and CX		Kawasaki disease	yes	Conservative	Not stated
Li (2005)	a	M	Prox RCA	Fistula to left ventricle		Congenital	yes	Surgery	Uneventful
		W	Prox LAD	Fistula to left ventricle		Congenital	Yes	Surgery	Uneventful
		W	Prox RCA	Fistula to left ventricle		Congenital	Yes	Surgery	Uneventful
		M	prox RCA	Fistula to left ventricle		Congenital	yes	surgery	uneventful
Kumar (2006)	73	W	Prox RCA	Aneurysm LAD		Atherosclerosis	Yes	Surgery	Died
Augustin (2006)	31	W	Prox RCA			?	Yes	Surgery	Uneventful
Kwon (2007)	68	W	LAD and RCA	Aneurysm fed by both coronaries		Atherosclerosis	Yes	Surgery	Not stated
Ghanta (2007)	64	M	Prox RCA			Atherosclerosis	Yes	Surgery	Uneventful
Blank (2007)	59	M	Prox RCA		Femoral	Atherosclerosis	Yes	Surgery	Not stated
Liu (2011)	26	M	Distal RCA	Fistula to left ventricle		Congenital	Yes	Surgery	Uneventful
Shimamura (2011)	37	W	Prox RCA			?	Unspecific	Surgery	Uneventful
Mora (2011)	79	M	Prox RCA	Aneurysm CX		Atherosclerosis	Unspecific	Surgery	Uneventful
Macy (2011)	71	M	Prox RCA			Atherosclerosis	Yes	No	Died
Keyser (2012)	43	M	Prox RCA	Aneurysm LAD		Atherosclerosis	Yes	Surgery	Uneventful

CAA: coronary artery aneurysm; Prox: proximal; RCA: right coronary artery; LAD: left anterior descending; CX: circumflex; PTC: percutaneous transfemoral coronary therapy.

^aMean 30–56 years.

DISCUSSION

CAAs most commonly develop secondary to atherosclerotic coronary artery disease [2–4]. Further CAAs are described as congenital [2] and are linked to Kawasaki disease [6]. Other circumstances, in which CAAs may develop, are rather exceptional: trauma and dissection, infectious, luetic, scleroderma, connective tissue disorders such as Marfan syndrome or Ehlers–Danlos syndrome and lupus, neurofibromatosis, periarteritis nodosa [3] and Takayasu's arterits. CAAs are also associated with cocaine abusers [7]. Since the introduction of percutaneous coronary interventions, CAAs have been described as the aftermath of these procedures [8]. Furthermore, giant saphenous vein graft pseudoaneurysms may develop after myocardial revascularization [9].

CAAs are frequently associated with aneurysms of other locations, in particular with aortic aneurysms [2, 4]. Further frequent locations of concomitant aneurysmatic changes are arterial segments iliofemorally [3]. Multislice computed tomography of our patient indicated no other malformation of arteries in the head, corpus, and extremities.

As aneurysms exceeding 5 cm in diameter are extremely uncommon, they might as well be an advanced stage of this disease. Only three of the described giant aneurysms >5 cm were located at the left coronary system: one has been described in accordance with Takayasu's arteritis, one involved both the right and the left coronary arteries, and one has been described as congenital, with a fistula to the left ventricle in the series of Li (Table 2). It seems remarkable that the two described giant saphenous vein graft pseudoaneurysms both developed in the graft supplying the right coronary artery [9].

The pathomechanism of CAAs remains a controversial topic of discussion. An inherent defect of the vessel wall may predispose to aneurysm formation in atherosclerotic vessels. Weakened media with a diminution of its elastic elements in areas of marked atherosclerosis, and intraluminal pressure against the vessel wall with decreased stress tolerance due to the destruction of the media subsequently permit the dilatation of the vessel wall at the area of defective structure [10]. Chronic transmural inflammation with the destruction of the media, including loss of elastic fibres and smooth muscle cells, as seen in atherosclerotic lesions aggravates this process.

Intraluminal thrombi develop. Parietal thrombi found in the lumen of aneurysms decrease the haemodynamic effect on the aneurismal wall. Thus, growth of the aneurysm may slow down. But, thrombi impair the access of nutritious substances into the vessel wall. The thrombus proteases may accelerate degradation of elastin, collagen and other structural proteins of the aneurismal wall, and this may contribute to the increase in the aneurysm [11]. A vicious circle of vessel wall weakening, wall stress, thrombus formation, impaired nutrition and again vessel wall impairment is inaugurated. The role of increased vasa vasorum, a commonly observed phenomenon of atherosclerotic lesions, is poorly defined.

As the vast majority of giant coronary aneurysms involve the right coronary artery and develop proximally, we may suggest adjacent topographic structures as relevant in the process of aneurysm formation. In comparison to other intrapericardial localizations, the low pressure of the right atrium as well as the atrioventricular sulcus may easily give way to an expanding aneurysmatic structure. This is not inconsistent with the three observed giant coronary aneurysms involving the left coronary system: the giant left coronary aneurysm described by Suzuki developed in Takayasu's arterits, Kwon described an aneurysm fed by both coronary arteries and Li described a congenital aneurysm with a fistula to the left ventricle, which certainly would have resisted the pressure of the left ventricle (Table 2). The topographic vicinity again may explain the two giant saphenous graft pseudoaneurysms [9].

The medical history of our patient with hypercholesterolaemia and the family history with multiple relatives who had suffered from myocardial infarction argue for an atherosclerotic aetiology. There is no historical or clinical clue for Kawasaki disease. Due to the dimension of the partially thrombosed right CAA and the calcified portions of its wall, it is highly suspected that this aneurysm must have existed for a considerable period of time before becoming clinically relevant. Yet the significant coronary artery sclerosis of the right coronary artery, the circumflex artery and the LAD with its large aneurysm tends to favour an atherosclerotic aetiology. Histopathological findings of samples of the aneurysms have confirmed an atherosclerotic origin. Therefore, we conclude that the aetiology of the disease of our patient must be atherosclerotic.

Acute thrombosis is found in 75% of the aneurysms [2, 12]. Embolization from these thrombotic aneurysms and consecutive myocardial ischaemia—as was possibly the case in our patient—may occur. Fistula to cardiac cavities are impressively described by Liu [13]. Ruptures of CAA have also been described [2]. Subsequent tamponade and/or sudden death may occur [10, 12]. Therefore, CAAs are an independent predictor of mortality with a 71% overall 5-year survival [5].

Therapeutical measures do not seem well defined. Without doubt, cases with myocardial infarction or rupture as well as aneurysms compromising the superior caval vein, the right atrium or even the right ventricular inflow tract are absolute indications for surgery. Successful surgery has been performed in asymptomatic aneurysms and in patients with unspecific complaints. One patient died during the surgical procedure due to right heart failure. The giant aneurysm had obstructed the right atrium and the right ventricle. The interventional exclusion of an aneurysm was also described as successful [14]. A conservative therapy including antiplatelet or anticoagulation medication has been recommended [15]. The outcome, though, is questionable, as two patients died, and the outcome of two other patients was not stated.

CONCLUSION

Taking into account that CAAs bear a significant risk of severe complications and have a high risk of mortality, a more aggressive surgical approach should be recommended.

Conflict of interest: none declared.