Case presentation

While preparing for bed, an active and healthy 66-year-old man developed sudden-onset substernal chest pain radiating to his jaw. This pain reminded him of the angina he had experienced 14 years earlier, prior to coronary bypass surgery consisting of a left internal mammary artery graft to the left anterior descending artery, a right internal mammary artery graft to the right coronary artery, and a saphenous vein graft to a large second obtuse marginal artery. The pain lasted for 15 minutes and resolved with nitroglycerin. Evaluation in the hospital emergency department found no electrocardiographic abnormalities or rise in cardiac biomarkers. Following hospital admission and treatment with aspirin, unfractionated heparin, atenolol, and long-acting nitrates, his cardiologist performed a stress echocardiogram. During this test, he developed recurrent chest pain along with marked ST depression at a low workload with stress-induced lateral wall hypokinesis on echocardiography. Physical examination and routine laboratory studies were normal and he was referred for cardiac catheterization.

Cardiac catheterization

Angiography found wide patency of both internal mammary artery grafts and a severe proximal stenosis and moderately severe, more distal stenosis in the body of the 14-year-old vein graft to the obtuse marginal artery (Figures 22-1, 22-2 and Videos 22-1, 22-2). The operator planned to stent both the proximal and midgraft lesions with distal embolic protection afforded by the PercuSurge Guardwire (Medtronic) temporary balloon occlusion and aspiration system.¹ An 8 French, right Judkins guide catheter was inserted in the vein graft. The operator chose unfractionated heparin and eptifibatide for procedural anticoagulation, and the Guardwire was positioned distally in the vein graft. The occlusion balloon was inflated to allow distal embolic protection. After first dilating with a 3.5 mm diameter balloon, a 4.5 mm diameter by 18 mm long bare-metal stent was deployed in the proximal lesion (Figure 22-3). The operator then positioned and deployed a 4.0 mm diameter by 28 mm long bare-metal stent in the midgraft lesion. Aspiration was performed, the distal occlusion balloon deflated, and angiography performed. To the operator’s horror, free-flowing contrast was observed extravasating from a large defect in the midportion of the vein graft within the stented segment (Video 22-3). The patient developed marked hypotension with arterial pressure falling to 50/30 mmHg. To staunch the hemorrhage, a 3.5 mm perfusion balloon was positioned and inflated in the vein graft at the site of the defect, eptifibatide was discontinued, and 30 mg of protamine was administered intravenously. This greatly decreased the amount of contrast extravasation, and the perfusion balloon allowed distal perfusion; however, there remained evidence of ongoing hemorrhage by angiography (Video 22-4). Fluid resuscitation and dopamine infusion restored blood pressure, but each time the balloon was deflated for even a few seconds, the patient developed marked hypotension. Since the operator did not feel there was sufficient time to safely exchange the perfusion balloon for a PTFE-covered stent nor felt confident that the large defect could be successfully sealed with this device, cardiothoracic surgery agreed to operate on the patient emergently.

FIGURE 22-1 Left anterior oblique projection of the saphenous vein graft to the obtuse marginal artery. A severe stenosis is apparent in the body of the vein graft (arrow).

FIGURE 22-2 Right anterior oblique view of the saphenous vein graft to the obtuse marginal artery. There is a severe stenosis in the body of the vein graft (arrow) followed by a long tubular narrowing more distally (double arrow).

FIGURE 22-3 Inflation of the stent balloon in the more proximal lesion in the saphenous vein graft.

Postprocedural course

To maintain hemodynamic stability and prevent further hemorrhage, the perfusion balloon remained inflated during transport to the operating room. Through a left thoracotomy, the surgeon first evacuated a large amount of blood in the pleural space, then repaired the perforation and placed a saphenous vein graft from the descending thoracic aorta to the circumflex marginal artery, just distal to the previous placed graft, which was subsequently ligated. The patient’s postoperative course was remarkably benign and he was ultimately discharged on postoperative day five. He had no additional angina during follow-up.

Discussion

Distal embolization, no-reflow, and periprocedural myocardial infarction are the operator’s major concerns when performing an intervention on a lesion in an old saphenous vein graft. Although the occurrence of rupture of a saphenous vein graft, as presented in this case, is very rare, the operator may encounter a rigid lesion in a saphenous vein graft. In such cases, full stent expansion may require high-pressure inflations and may result in perforation.

A saphenous vein graft perforation may behave differently than one involving a native coronary artery. A saphenous vein graft may be more prone to perforation since, in a native coronary artery, the presence of a thicker muscular layer, as well as a more robust adventitia and an overlying layer of subepicardial fat, may help contain a deep dissection or smaller perforation that might lead to free bleeding if a similar injury involved a vein graft, which lacks these protective layers. Alternatively, in the event of a definite breach of the vessel during intervention, a perforation of a saphenous vein graft may be less likely to cause tamponade. If the lesion involves the proximal segment of the vein graft, a rupture may cause bleeding into the pleural instead of the pericardial space. Furthermore, the existence of pericardial adhesions or the persistence of a pericardiotomy created at the time of bypass surgery might protect the patient from developing tamponade, should the bleeding enter the pericardial space. Although the case presented here bled into the pleural space and the patient did not develop tamponade, the rupture still led to dramatic hemodynamic collapse from free bleeding into the pleural space. In addition, tamponade may still occur in these cases because the pericardium may reflect high onto the ascending aorta, there may be minimal adhesions, and the pericardial opening made during surgery may close.²

Treatment strategies for native coronary artery perforation have been discussed in other cases in this section involving perforation. These basic principles are also applicable to a saphenous vein graft perforation. Similar to native coronary arteries, the outcome of the perforation will depend on the size of the defect.³ The case presented here is an example of a Type III perforation with freely flowing contrast from an exit hole greater than 1 mm in diameter. Simple measures, such as reversal of anticoagulation and prolonged balloon inflation at the site of the perforation, could not be expected to effectively seal such a large defect. A covered stent might have succeeded; however, the operator chose surgery, primarily based on the large size of the defect and the concern that a covered stent might not necessarily seal the rupture. Furthermore, release of the occluding balloon for even a few seconds led to prompt hemodynamic instability. An attempt at a covered stent would have been technically challenging under these circumstances.

As exemplified in this case, emergency surgery is necessary when there is ongoing bleeding from a coronary perforation despite reversal of anticoagulation and institution of measures to treat the perforation, such as prolonged balloon inflation or use of a covered stent graft. Overall, between 10% and 40% of patients with coronary perforation are treated surgically black^4–6; surgery is less likely to be necessary when the perforation is small and not associated with tamponade or hemodynamic instability. In this case, a perfusion balloon was used to occlude the bleeding site while allowing distal perfusion of the artery, thereby limiting ischemia during the time required for transport to the operating room. Unfortunately, perfusion balloons are no longer commercially available, thereby removing this strategy as an option in the current era.