Case presentation

A 57-year-old woman with prior bypass surgery consisting of a left internal mammary graft to the left anterior descending artery and a saphenous vein graft to the right coronary artery presented with the acute onset of prolonged rest chest pain and an elevated troponin I (7.0 ng/mL). In addition to the prior bypass surgery, other important medical history included diabetes, end-stage renal disease treated with hemodialysis, and a prior episode of ventricular tachycardia resulting in implantation of a defibrillator.

Coronary angiography performed at another hospital demonstrated patent bypass grafts but severe disease in the ungrafted ramus intermedius and left circumflex arteries. Initially treated medically, she reported ongoing severe angina and was referred for coronary intervention of the ramus and circumflex arteries.

Cardiac catheterization

Representative angiograms of her left coronary artery are shown in Figures 29-1, 29-2 and Videos 29-1, 29-2. A complex lesion was present in the proximal portion of the ramus intermedius at a bifurcation. The proximal to midsegment of the circumflex was also severely diseased. Importantly, this artery branched from the left main with marked angulation, clearly seen in the left anterior oblique view with caudal angulation (see Figure 29-1).

FIGURE 29-1 This is a left anterior oblique projection of the left coronary artery demonstrating severe disease in both the ramus intemedius and the left circumflex artery. Note the extreme angulation of the circumflex relative to the left main coronary artery.

FIGURE 29-2 This is a right anterior oblique projection with caudal angulation demonstrating the ramus and circumflex lesions.

Procedural anticoagulation was accomplished with an intravenous heparin bolus to achieve an activated clotting time greater than 300 seconds and a supportive guide catheter was chosen (6 French JCL 4.5). The operator began with the ramus intermedius (Figure 29-3). This lesion was successfully treated with balloon angioplasty (2.5 mm diameter by 15 mm long compliant balloon) followed by placement of an everolimus-eluting stent (2.75 mm diameter by 18 mm long) (Figure 29-4 and Video 29-3).

FIGURE 29-3 A balloon angioplasty followed by stenting of the ramus intermedius was performed with protection of a lower branch of the ramus.

FIGURE 29-4 This angiogram depicts the result of intervention on the ramus intermedius branch.

Following the successful procedure on the ramus intermedius, the operator turned attention to the circumflex. Due to excessive angulation, the operator was unable to pass a 0.014 inch floppy-tipped conventional guidewire; a hydrophilic guidewire ultimately proved successful. The operator used a compliant balloon (2.5 mm diameter by 15 mm long) to predilate the lesion (Figures 29-5, 29-6 and Video 29-4) then removed the balloon catheter and attempted to pass an everolimus-eluting stent (3.0 mm diameter by 15 mm long). This was not successful because the stent would not advance around the acute angle. The guidewire was replaced with a stiffer shaft wire (Boston Scientific Mailman) and a shorter bare-metal stent was also attempted (3.0 mm diameter by 9 mm long) but failed to advance as well. During attempts to advance the stent, the guide catheter disengaged and distal wire access was lost. The guide was reengaged. Again, the operator had great difficulty advancing a 0.014 inch polymer-tipped guidewire and created a dissection resulting in vessel closure (Figures 29-7, 29-9 and Videos 29-5, 29-6). Attempts to regain the distal lumen using a variety of other guidewires failed. The patient reported chest pain but remained hemodynamically stable without arrhythmia. At this point, the procedure was stopped and the patient admitted to the coronary care unit.

FIGURE 29-5 With great difficulty, a guidewire was advanced into the circumflex artery and balloon angioplasty performed.

FIGURE 29-6 This is the angiographic appearance of the circumflex after balloon angioplasty. In retrospect, the operator would have settled for this result!

FIGURE 29-7 After losing access to the artery, attempts at recrossing the lesion resulted in extensive dissection of the artery as shown (arrow).

FIGURE 29-9 Final appearance of the artery with closure of the circumflex.

Postprocedural course

After admission to the coronary care unit, she was placed on an intravenous infusion of nitroglycerin. She continued to report chest pain for several hours. An admission electrocardiogram demonstrated lateral ST-segment depression and an initial troponin I was 0.04 ng/mL, peaking 20 hours after the intervention at 19.51 ng/mL. Transthoracic echocardiogram showed mild inferoposterior hypokinesis with preserved ejection fraction. She became free of chest pain, was observed in-hospital for several days, and was ultimately discharged on carvedilol, clopidogrel, aspirin, simvastatin, and lisinopril. She remained free of symptoms at 6-week follow-up.

Discussion

Abrupt vessel closure after angioplasty is a serious complication associated with death, myocardial infarction, or need for emergency bypass surgery.¹ Most cases of abrupt vessel closure are due to extensive dissection of the artery with vessel occlusion caused by intimal flaps, intramural hematoma, or thrombus. During the balloon era, abrupt vessel closure complicated 2% to 8% of

FIGURE 29-8 Contrast retention due to the extensive dissection is shown here (arrow).

coronary interventions and the only definitive therapy consisted of emergency bypass surgery. Coronary stents offered the first effective percutaneous solution and dramatically reduced the need for emergency surgery.

Despite the advances in technology, abrupt closure remains an important risk in the current era. As demonstrated by this case, the inability to deliver a stent to a complex lesion or an extensively dissected segment leaves the operator few options in the event of vessel closure. Proximal vessel tortuosity, extreme angulation, heavy coronary calcification, and noncompliant vessels are all scenarios where a stent might not be deliverable. At this juncture, the operator is faced with the decision of emergency bypass surgery versus conservative medical management of the closed vessel and associated myocardial infarction. Emergency bypass surgery, still necessary in about 0.4% of percutaneous coronary interventions, is a fairly morbid event, associated with an in-hospital mortality of 8%, and is more likely to be justified when the occluded vessel supplies a large amount of myocardium.² In the case presented here, the benefit of revascularizing a small vascular territory was greatly outweighed by the risk of emergent surgery in a patient with significant comorbid conditions.

The difficult anatomy present in this case set the stage for this complication. Extreme angulation of the origin of the circumflex from the left main stem made it difficult to torque and advance guidewires, necessitating the use of a polymer-tipped wire. Although this allowed successful passage and enough support for balloon dilatation, a stent could not be delivered. The fateful event occurred when the operator lost guidewire access. There were probably numerous small intimal tears in the lesion caused by balloon angioplasty. Attempts to recross this complex lesion undoubtedly propagated these tears, leading to the extensive spiral dissection observed in this case. The complex labyrinth of intimal flaps thwarted the operator’s attempts at finding the true distal lumen, especially given the extreme angulation and inability to precisely turn and advance the guidewire.