Case presentation

The onset of severe substernal chest pain awakened a 50-year-old diabetic woman without prior cardiac history from her sleep. The pain waxed and waned all morning until she finally presented to the emergency room 9 hours later. She was found to have an inferior wall ST-segment elevation myocardial infarction and was taken emergently to the cardiac catheterization laboratory. As suspected, based on the electrocardiographic changes, the right coronary artery was completely occluded (Figure 13-1); however, the operator was surprised to find severe and complex disease affecting the left anterior descending (LAD) and diagonal arteries (Figure 13-2 and Video 13-1) and moderate disease in the left circumflex artery (Figure 13-3 and Video 13-2). Lush collaterals filled the distal right coronary artery from the left coronary injections.

FIGURE 13-1 This is the occluded right coronary and the infarct-related artery.

FIGURE 13-2 The left anterior descending artery was severely diseased, with complex disease involving the diagonal and the bifurcation. There is also distal disease present (arrow).

FIGURE 13-3 There is moderate disease of the obtuse marginal artery and collaterals to the right coronary artery (arrow).

With the goal of achieving rapid reperfusion of the infarct-related artery, the operator decided to open the right coronary artery. This was promptly and successfully accomplished with balloon angioplasty followed by deployment of two 4.5 mm diameter bare-metal stents. The operator obtained an excellent luminal result and TIMI-3 flow (Figure 13-4 and Video 13-3).

FIGURE 13-4 Angiogram obtained after stenting the right coronary artery.

She recovered uneventfully from the acute infarction. During this hospitalization, a transthoracic echocardiogram showed an ejection fraction of 35% to 40% from an extensive inferoposterior wall motion abnormality. Uncertain about the optimal management of the incidentally-noted disease in the LAD and diagonal branch, her physician carefully considered several options. Surgical revascularization was thought to be unattractive because of the small caliber of the vessel and the presence of diffuse disease distally at the site of the usual graft anastomosis. Percutaneous revascularization would be complex and technically difficult because of the presence of bifurcation disease in the LAD and the small caliber of the LAD and diagonal vessels. In addition, given the recent sizeable inferior infarction and reduced left ventricular function, a PCI-related complication involving the LAD, such as abrupt vessel closure or loss of the diagonal side branch, might lead to serious morbidity and even death. Based on these considerations, her physician decided to pursue aggressive medical therapy as the initial management strategy. Thus, she was discharged on aspirin, clopidogrel, metoprolol, lisinopril, and atorvastatin.

At follow-up 2 months later, she reported significant shortness of breath associated with substernal chest pain when walking up the stairs at her home. A repeat echocardiogram showed improvement in left ventricular function with ejection fraction of 45% to 50%. Her physician again weighed the risks and benefits of surgery, percutaneous revascularization of the LAD, or continued medical therapy and referred her for stenting of the LAD.

Cardiac catheterization

She returned to the cardiac catheterization laboratory for an elective complex intervention of the LAD and diagonal. After achieving therapeutic anticoagulation, the operator advanced 0.014 inch floppy-tipped guidewires in both the LAD and diagonal and performed balloon angioplasty in the LAD with a 2.0 mm diameter by 20 mm long compliant balloon (Figure 13-5). The first diagonal was then treated with two everolimus-eluting stents; the first one (2.5 mm diameter by 14 mm long) placed in the mid-diagonal (Figures 13-6, 13-7) and a second one (also 2.5 mm diameter by 14 mm long) placed in the diagonal but extended into the proximal part of the LAD (Figures 13-8, 13-9 and Video 13-4). The operator withdrew the LAD wire to the guide catheter because the wire was trapped behind the latter stent. This guidewire was then repositioned in the distal LAD through the stent struts. Balloon angioplasty was performed and a single 2.5 mm diameter by 18 mm long everolimus-eluting stent positioned in the LAD using a “T” configuration just distal to the diagonal bifurcation (Figure 13-10). Following the deployment of this stent, the ostium of the diagonal was postdilated with a 2.5 mm diameter noncompliant balloon (Figure 13-11). The final angiographic result, shown in Figure 13-12 and Video 13-5, appeared satisfactory to the operator.

FIGURE 13-5 First, the LAD was treated with balloon angioplasty after a guidewire was positioned in the diagonal branch.

FIGURE 13-6 Next, the operator stented the diagonal branch.

FIGURE 13-7 Angiographic appearance after the first diagonal stent was placed.

FIGURE 13-8 The proximal end of the diagonal was treated with another stent that extended into the LAD.

FIGURE 13-9 Angiographic appearance after the second diagonal stent was placed.

FIGURE 13-10 After repositioning the LAD wire through the stent struts and performing balloon angioplasty, the LAD stent was placed flush to the origin of the diagonal side branch.

FIGURE 13-11 As a final step, the operator ballooned the origin of the diagonal to ensure proper stent apposition.

FIGURE 13-12 Final angiographic result after stenting the LAD and diagonal.

Postprocedural course

Her post-PCI course was uncomplicated and she was discharged the following morning. She remained event- and symptom-free at follow-up 15 months later.

Discussion

The complex disease and challenging revascularization decisions evident in this case are familiar to practitioners of interventional cardiology. This patient first presented with an ST-segment elevation myocardial infarction. At that point, the physician’s primary focus was to achieve prompt reperfusion of the infarct-related artery; this was successfully accomplished using percutaneous techniques. However, during this procedure, significant obstructive coronary disease was identified in the non-infarct–related arteries. The decision regarding how to best manage this other coexisting disease was not entirely clear to the physician, as each of the various options had limitations, risks, and uncertainty.

First, it was not clear if and when revascularization of this other disease was indicated. Multivessel coronary disease is found in up to 60% of patients undergoing emergent cardiac catheterization for ST-segment elevation myocardial infarction.^1–3 The optimal management of these “bystander” lesions is unclear and controversial. Because of the concern about the risks of intervening upon a non-infarct–related artery when there is acute infarction in another vascular territory, current practice guidelines discourage the performance of an intervention on obstructive lesions in the non-infarct–related artery at the time of acute infarct angioplasty. It is not known if these lesions should be treated during the hospital phase while the patient is still recovering from the infarction, in the weeks to months following the event when the infarction has healed, or deferred indefinitely unless there is objective evidence of ischemia. In this case, the complexity of the disease led to the decision to pursue medical therapy as the initial strategy. During follow-up, her ongoing symptoms despite appropriate medical therapy caused her physicians to recommend revascularization.

Second, once it was determined that the patient needed revascularization, it was not clear how it might best be accomplished. Surgical revascularization might have been the simplest solution, but the small caliber of the patient’s arteries as well at the presence of diffuse disease located at the usual site of a graft anastomosis discouraged her physicians from pursuing this option. Percutaneous revascularization was also problematic and associated with increased risk because of the presence of bifurcation disease and small-caliber arteries.

Finally, once the option of percutaneous revascularization was chosen, the operator was faced with several crucial technical decisions regarding treatment of the complex disease. The small caliber of the involved arteries (<2.5 mm diameter) is associated with an increased risk of procedural complication and an increased risk for restenosis. Bare-metal stents are superior to balloon angioplasty in small arteries but are associated with at least a 25% restenosis rate⁴; this rate approaches 50% in diabetics. Drug-eluting stents reduce the rate of restenosis in small arteries compared to bare-metal stents.^5,6 In the present case, it was not clear to the operator that the involved arteries were large enough to accommodate a drug-eluting stent; fortunately, 2.5 mm diameter drug-eluting stents were successfully placed without creating distal edge dissections or other complications. Management of the bifurcation represented another significant technical challenge. Because of the diffuse disease in the distal LAD, the operator decided to prioritize the large diagonal branch and considered the LAD the “side branch” vessel. Choosing a relatively simple approach to stenting the bifurcation and avoiding overlapping stents at the bifurcation in this diabetic patient with small-caliber vessels likely contributed to the excellent outcome.