Asymptomatic large coronary artery saphenous vein bypass graft aneurysm: A case report and review of the literature

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Asymptomatic large coronary artery saphenous vein bypass graft aneurysm: A case report and review of the literature

Joseph N. Wight, Jr., MD, Deeb Salem, MD, FACP, FACC, Mani A. Vannan, MBBS, MRCP, MRCPI, Natesa G. Pandian, MD, FACC, Mark Bankoff, MD, Marc I. Rozansky, MD, Joseph P. Semple, MD, Michael C. Dohan, MD, FACC, and Hassan Rastegar , MD, FACS Boston, Mass.

Relat ively few cases of saphenous vein graft (SVG) aneu- rysms have been repor ted since the introduction of saphe- nous vein coronary bypass graft ing in 1968 by Favaloro. 1, 2 The maj ority of reports are descriptions of t rue aneurysms of the body of the SVGs or pseudoaneurysms located at or near the anastomosis sites. 337 We repor t an unusua l case of a large SVG aneurysm tha t presented as an asymptom- atic medias t ina l mass. To our knowledge, this is the larg- est repor ted asymptomat ic t rue aneurysm of a saphenous vein aortocoronary bypass graft.

From the Division of Cardiology, Department of Medicine, Department of Radiology, Department of Pathology, and Department of Cardiothoracic Surgery, New England Medical Center Hospitals, Tufts University School of Medicine. Reprint requests: Deeb Salem, MD, 750 Washington St., Division of Car- diology, New England Medical Center Hospitals, Tufts University School of Medicine, Boston, MA 02111. Am Heart J 1997;133:454-60. Copyright © 1997 by Mosby-Year Book, Inc. 0002-8703/97/$5.00 + 0 4/4/75311

A 63-year-old white man with hypercholesterolemia who had undergone four-vessel coronary a r te ry bypass surgery 15 years ear l ier was found to have a large, anter ior medi- as t inal mass on chest rad iography tha t was obtained as par t of a rout ine preoperat ive evaluat ion before the re- moval of a symptomat ic bone spur on his r ight foot. Dur- ing coronary revascular izat ion in 1980, he had the follow- ing grafts placed: reverse SVG (RSVG) to the left anter ior descending (LAD) coronary artery, sequential RSVG to the second and th i rd obtuse marg ina l coronary arteries, and RSVG to the r ight coronary a r te ry (RCA). At tha t t ime, varicose veins were noted dis ta l ly in the pat ient ' s leg, but no ment ion was made of any abnormal findings or of t r a u m a to the SVGs. The pa t ien t had no his tory of leg t rauma, and surgery was uneventful.

In the immedia te postoperat ive period, he had a tem- pera tu re of 40 ° C and was t rea ted with tobramycin. The pat ient ' s fever aba ted on the fourth postoperat ive day, and he was discharged home 7 days later . Dur ing the 15 years after coronary a r te ry bypass grafting, he had no fur ther cardiac symptoms. The pa t ien t s ta ted tha t he was walking 3 to 4 miles per day without difficulty. On physical exam- ination, he was a hea l thy looking white man in no distress. Blood pressure was 130/70 m m Hg in his r ight a rm and 126/70 m m Hg in the left. Hear t ra te was 60 beats /min with a respi ra tory ra te of 16 breaths/rain. Per t inent findings included a prominent pulmonic valve closure sound and a grade 2 systolic ejection m u r m u r at the left upper s ternal border consistent with a flow murmur . No diastolic mur- mur was heard. The resul ts of the examinat ion were nor- mal. The labora tory data, including a complete blood cell count, serum electrolytes, blood urea nitrogen, creatinine, coagulation studies, and urinalysis , were wi thin normal

Fig. 1. Posterior and anter ior (A) and la te ra l (B) chest radiographs show large anter ior medias t ina l den- si ty adjacent to left ventricle.

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Fig. 2. Two thoracic computed tomography images at level of bifurcat ion of pu lmonary artery. A, Without contrast . B, After in t ravenous contrast .

l imits. The electrocardiogram revealed sinus bradycard ia wi th an incomplete r ight bundle branch block and inferior Q waves consistent wi th a previous inferior infarction. The chest rad iograph demons t ra ted a large anter ior mass ad- j acen t to the left hea r t border (Fig. 1).

F u r t h e r diagnostic evaluat ion included a computed tomographic scan of the chest t ha t revealed a large left an- ter ior medias t ina l mass abu t t ing the left ventricle (supe- rior aspect), r ight ventricle, and pulmonary a r te ry (Fig. 2). The mass was of low a t tenua t ion on noncontras t images wi th per iphera l calcifications. A tubu la r s t ructure ex- tended from the superior aspect of the mass to abut the as-

cending aor ta a t the expected site of the graf t origin. After in t ravenous contrast , the tubu la r s t ructure enhanced to a s imilar degree as the aor ta and pu lmonary ar tery, con- f irming i ts vascular nature . In addition, there was a par- t ia l filling of the mass. Transthoracic echocardiogram (Fig. 3) demonst ra ted a large, an te ro la te ra l cystic mass tha t was par t ia l ly filled wi th thrombus. Al though there was r ight ventr icular outflow t rac t compression, no evidence of hemodynamic obstruction by Doppler examinat ion was found. The left ventr icular ejection fraction was 45%. The remainder of the s tudy resul ts were normal. Once the di- agnosis of an SVG aneurysm was suspected, r ight hea r t

April 1997 456 Wight et al. American Heart Journal

Fig. 3. Two transthoracic parasternal short-axis images. Anterior structure is saphenous vein graft an- eurysm (arrows), which is partially filled with thrombus. Left ventricle is seen posterior to aneurysm. Im- age at left is at level ofmitral valve (MV). Aneurysm is seen at level of left ventricular outflow tract (LVOT) (right).

Fig. 4. Coronary angiography of SVG aneurysm in two projections. At left, anterior posterior (AP) view demonstrates aneurysmal SVG to left anterior descending artery. Only true lumen of graft fills with con- trast. Right anterior oblique (RAO) view is at right.

catheterization, coronary angiography, left and right ven- triculography, and aortography were performed. Pul- monary artery pressure (38/22 mm Hg) and pulmonary capillary wedge pressure (21 mm Hg) were mildly to mod- erately elevated. Angiography revealed total proximal oc- clusion of the LAD, left circumflex, and RCA and an 80% proximal stenosis of a diffusely diseased trifurcation ar- tery. The RSVG to the RCA was occluded proximally. The sequential RSVG to the second and third obtuse marginal arteries was patent. The RSVG to the LAD was patent with a large aneurysmal dilatation. However, the patent lumen represented a small portion of the total aneurysm (Fig. 4). Left ventriculography revealed mild inferobasilar hypo- kinesis. Right ventriculography demonstrated normal ven- tricnlar function without evidence of an atrial, ventricnlar, or pulmonary artery fistula. Aortography showed no aor- tic root dilatation.

Because the risk of vein graft rupture was significant and is associated with a high mortality rate and excessive morbidity,* the patient was referred for surgical excision of the SVG aneurysm and revascularization. An intraop- erative transesophageal echocardiogram was performed. From the transgastric view, the left ventricular cavity was visualized in short and long axis (Fig. 5). The SVG aneu- rysm was seen adjacent to the anterior wall of the left ven- tricle. The lumen was largely replaced by thrombus. The long-axis view defined the origin of the graft as it emerged from the ascending aorta. The left ventricular ejection fraction was 45% with inferobasilar hypokinesis. The remainder of the study findings were normal.

At surgery, a large 10 x 10 × 6 cm true aneurysm of the SVG to the LAD was removed (Fig. 6). It contained friable,

*References 5,7,8,10,20,21,24,27.

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Fig. 5. Transgastric views of intraoperative transesophageal echocardiogram. At left, short-axis view of left ventricle (LV) and right ventricle (RV) with large SVG abutting anterior wall (arrow). At right, long- axis view of left ventricle and left ventricular outflow tract (LVOT). SVG aneurysm is seen originating from ascending aorta (arrow).

Fig. 6. SVG aneurysm being retracted by surgeon's hand. Aneurysm measured 10 × 10 × 6 cm.

gelatinous, tan-gray layered fibrin and thrombus that ap- peared to have accumulated over a period of years (Fig. 7). The lumen of the graft was patent (Fig. 8). Microscopically, focal calcification and fresh thrombus were also seen. The distal segment of the aneurysm demonstrated intimal proliferation and a complex atherosclerotic plaque. The patient tolerated the surgery well and was discharged af- ter 6 days. He continues to do well 6 months after surgery.

DISCUSSION

Although a minor degree of aneurysmal dilatation of SVG has been found to be as high as 14% 6 to 12 years af-

ter coronary artery bypass surgery, 28 significant aneurys- mal dilatation of a saphenous vein after coronary artery bypass surgery is an unusual event. Our review of the lit- erature found 14 pseudoaneurysms* and 21 true aneu- rysms.t The cause and location can differ between pseudo- aneurysms and true aneurysms, although the clinical pre- sentation and size do not.

SVG pseudoaneurysms usually occur at the proxi-

*References 5,7,8,10-13,15,19,21,26,27,32.

tReferences 3,4,6,9,16-18,20,22-24,32,33,35-37.

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458 Wight et al. American Heart Journal

Fig, 7, Ge•atinous•fr iab•e•gray-tan•brinandthr•mbusafterincisi•nwasmadeint•veingraftaneurysm.

Fig. 8. Probe is passed through pa ten t lumen of vein graft aneurysm after excision.

mal or dis tal anastomotic site, 13 al though at least in one case the pseudoaneurysm occurred in the body of the graf t in a pa t ien t with aneurysms of the nat ive coronary arteries. 24 Pseudoaneurysms are thought to be caused by tension on the graft anastomosis , leading to suture rup- ture, or from erroneous p lacement of a suture. 15 Infection has also been associated with the development of these aneurysms. 5,2931 Fur thermore , pseudoaneurysms are more l ikely to be seen wi thin the first few months after surgery, but they have been repor ted up to 17 years af ter

coronary a r t e ry bypass grafting,* and they may be as large as 10 cm. 7,12,19, 27

In contrast , t r u e aneurysms of SVGs have been associ- a ted with atherosclerosis and hyperl ipidemia, is, 2s, 32, 33 Weakness in the graft wall near valve si tes has also been implicated as a cause. 34, 85 Here, the muscle layer of the vein changes from circular to longitudinal , which may predispose to aneurysmal di latat ion. 34,35 Undetected

*References 5,7,8,10-13,15,19,21,24,26,27,32.

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venous varicosit ies with impai red elastic t issue in tegr i ty have also been suggested as a possible mechanism. 36 True aneurysms most often present after several years, al- though two cases have been repor ted at 6 months. 35, 37 These aneurysms have also been described as being as large as 8 cm. 25

Occasionally, SVG aneurysms are incidental ly detected as an anter ior medias t ina l mass on chest radiography, but they are more often found as a resul t of a clinical even t . 327

Most commonly, the first manifes ta t ion of a large vein graft aneurysm is uns table angina or myocardia l infarc- tion.6,11-13,16, 25-27, 32 Complete thrombosis of the graft lu- men or coronary a r t e ry emboli or iginat ing in the graft ac- count for this presentat ion. 6, 25 Sometimes graft rup tu re can be the ini t ia l presenta t ion and lead to hemothorax, hemomedias t inum, or sudden death. 1°, 20, 21, 24 Rupture of a pseudoaneurysm leading to superior vena caval syn- drome and cardiogenic shock has also occurred. 8 Other presenta t ions have included SVG aneurysm fistula to the r ight a t r ium causing a left-to-right shunt and dyspnea, and SVG aneurysm fis tula formation to the r ight ventricle leading to coronary steal and myocardial infarction. 19, 22 Before this report, only five cases have been seen as an asymptomat ic anter ior chest mass, wi th the larges t re- ported aneurysm being 6 x 5 x 4 cm. 3' 4, 14, 15, 37

The diagnosis of a large vein graft aneurysm can be made by several modalit ies. The ini t ial evaluat ion of these pat ients usual ly includes a chest radiograph, which often demons t ra tes an anter ior mass near the hi lum or abut t ing the hea r t border. This f inding should point to a possible vein graft aneurysm in the pa t ien t who has undergone coronary bypass, a l though es tabl ishing the diagnosis on the basis of this alone would be unlikely. Fu r the r investi- gat ion by computed tomography, magnet ic resonance im- aging, or echocardiography ( transthoracic and t ransesoph- ageal) have successfully made or ass is ted in the diagnosis of SVG aneurysms and have also been able to dis t inguish t rue aneurysms from pseudoaneurysms. 3, 5-7, 9-12,14,17, 19 One repor t used in t ravascu la r u l t rasound with three- dimensional reconstruct ion of a t rue aneurysm to ass is t an

36 angioplasty of a more proximal stenosis. Despite the fact t ha t the diagnosis of an SVG aneurysm can be made by one of several noninvasive tests , coronary angiography mus t stil l be pursued before surgery to determine vein graft pa- tency and nat ive coronary anatomy. Coronary angiogra- phy is also useful to confirm the diagnosis. On two occasions computed tomography has mis in te rpre ted SVG aneurysms as solid masses. 4, 26

Because the ra te of rup ture of vein graft aneurysms aP- pears to be high and associated with extensive morbidi ty and mortal i ty , we and others recommend surgical excision of large, pa ten t SVG aneurysms.* Recent reports have shown tha t revascular izat ion has been successful in t rea t - ing these aneurysms . t Alternat ively, embolization of leak- ing grafts has been successfully performed in three Cases

*References 6,14,15,22,23,26,30,32.

tReferences 8,14,15,19,23,26,30,32.

in which the pa t ien t was not considered an operat ive can- d idate or wi th complete thrombosis of the graf t lumen with l i t t le or no viable myocardium supplied by the graft.5, 7, 27 Coil embolization is best performed by skil led operators to prevent misplacement or dis lodgment of the coil to an un- desired location.

This case demonst ra tes an unusua l presenta t ion of a large SVG aneurysm. Most pat ients wi th SVG aneurysms of this size are seen with symptoms. This pat ient , however, was asymptomatic , and the large SVG aneurysm was first detected by rout ine chest radiography. Clinical suspicion of a SVG aneurysm was subsequent ly confirmed by echocar- diography, computed tomography, and cardiac catheter- ization. Surgical excision of the SVG aneurysm and re- vascular izat ion led to a successful outcome. Although we cannot be certain, varicosit ies of the saphenous vein t ha t were used for the graft seemed to be the most l ikely cause of the large SVG aneurysm in this pat ient .

In conclusion, SVG aneurysms need to be considered in the differential diagnosis of a pa t ien t who has undergone bypass surgery and is seen with a medias t ina l mass. An organized approach, including noninvasive evaluat ion and coronary angiography, should lead to the diagnosis and an appropr ia te t r ea tmen t plan.

We thank Bob Sheehan for photography.

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4. Lopez-Velarde P, Hallman GL, Treistman B. Aneurysm of an aortocor- onary saphenous vein bypass graft presenting as an anterior medias- tinal mass. Ann Thorac Surg 1988;46:349-50.

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15. de Haan HPJ, Huysmans HA, Weeda HWH, Bosker HA, Buis B. Anas- tomotic pseudoaneurysm after aorte-coronary bypass grafting. Thorac Cardiovasc Surg 1985;33:55-6.

16. Wester DJ, Martinez HO, Camp A. Aneurysm of a saphenous vein graft manifested as a mediastinal mass on chest radiographs. AJR 1993; 161:951-2.

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Stenting within a stent: Treatment for repeat in-stent restenosis in a venous graft

Nadia Debbas, MD, PhD, Jean-Christophe Stauffer, MD, Eric Eeckhout, MD, PhD, Pierre Vogt, MD, Lukas Kappenberger, MD, and Jean-Jacques Goy, MD Lausanne, Switzerland

Restenosis after conventional balloon angioplasty remains one of the main drawbacks, particularly in venous grafts.i Hence, stenting has been advocated as primary and secondary prevention of restenosis in g r a f t s . 2 We report a patient in whom, over time, repeat stenting of the same le- sion has been necessary and successful.

In May 1992, a male patient aged 70 years was seen with New York Heart Association class II angina pectoris. He had a history of coronary heart disease since July 1991, when he underwent coronary artery bypass surgery for two-vessel disease, the right coronary (RCA) and the left circumflex (LCX) arteries. Clinical investigation of his an- gina included a positive exercise stress test result followed by a coronary angiogram. The angiogram showed no left main stem or left anterior descending (LAD) lesions. The native LCX was occluded at its origin. The RCA was sub- occluded with retrograde perfusion from the LAD. The venous graft to the RCA was occluded. There was a tight stenosis on the LCX graft (Table I, Fig. 1, A). Conventional balloon angioplasty of the lesion was successfully per- formed with good angiographic results as measured by quantitative coronary angiography (Fig. 1, B). (In our in- stitution, all angioplasty procedures are performed after administration of an intraarterial bolus injection of hepa- rin 15,000 IU and an oral dose of aspirin 500 mg.) He was discharged receiving aspirin 250 mg daily with atenolo150 mg daily and captopril 12.5 mg twice daily for hyperten- sion. He did well for 5 months, when he started experienc- ing crescendo angina and finally unstable angina. In De- cember 1992, restenosis in the LCX graft was documented and treated with renewed angioplasty followed by implan- tation of a Wiktor stent (Medtronic, Minneapolis, Minn.) with very good clinical and angiographic results (Fig. 2). Treatment included aspirin 250 mg and, for 6 months, dipyridamole 150 mg twice daily and oral anticoagulation with warfarin to reach an international normalized ratio between 2.0 and 3.0. The patient was asymptomatic until July 1994, 19 months after stent placement, when he started experiencing shortness of breath on slight exertion and complained of occasional palpitations. Control exer- cise stress test results were positive for ischemia. A further

From the Division of Cardiology, Centre Hospitalier Universitaite Vaudois.

Reprint requests: J. J. Goy, MD, Division of Cardiology, Centre Hospitalier Universitaite Vaudois, 1011 Lausanne, Switzerland.

Am Heart J 1997;133:460-3.

Copyright © 1997 by Mosby-Year Book, Inc. 0002-8703/97/$5.00 + 0 4/4/76253