Case presentation

A 63-year-old woman with hypertension, tobacco abuse, and dyslipidemia, but no prior coronary events, developed stable angina pectoris. Her physician evaluated these symptoms with an exercise stress test. During the stress test, chest discomfort began at a low workload and the scintigraphic images revealed reversible perfusion defects in multiple zones, including the inferior and anterior walls and the apex. She was referred for an elective cardiac catheterization.

Cardiac catheterization

Diagnostic catheterization found normal left ventricular function and significant stenoses in the proximal segment of the right coronary artery (Figure 19-1 and Video 19-1) and in the left anterior descending artery (Figures 19-2, 19-3 and Video 19-2). The left circumflex artery appeared angiographically normal. Coronary calcification was noted in both the right coronary and left anterior descending arteries. After discussing the options of medical therapy, coronary bypass surgery, and percutaneous coronary intervention, the patient chose a percutaneous revascularization strategy.

FIGURE 19-1 This is a left anterior oblique projection of the right coronary artery demonstrating the severe stenosis in the proximal segment. An Amplatz guide catheter was used to acquire this image (arrow).

FIGURE 19-2 This angiogram of the left coronary artery in a right anterior oblique projection with caudal angulation depicts the severe stenosis of the left anterior descending coronary artery after a first septal perforator (arrow). The circumflex is free of angiographic disease.

FIGURE 19-3 Angiography of the left coronary artery in the right anterior oblique projection with cranial angulation, demonstrating the lesion in the left anterior descending artery (arrow).

After administration of a bolus of 70 U/kg of unfractionated heparin followed by a double bolus and infusion of eptifibatide, the operator first approached the left anterior descending artery. The lesion was first dilated with a balloon and then treated with a sirolimus-eluting stent (Figure 19-4). The operator then turned attention to the right coronary artery. Anticipating the need for extra backup to support the intervention, due to the presence of coronary calcification noted on the diagnostic study, the operator chose a left Amplatz guide catheter (AL-2), as shown in Video 19-1. Although this guide catheter appeared to provide excellent support, pressure damping and retention of contrast in the arterial wall was observed in the proximal segment consistent with a guide-related dissection, leading to the exchange of the Amplatz guide for a right Judkins guide catheter. Upon engagement, the physician noted distal extension of the dissection, with retention of contrast nearly to the bifurcation of the posterior descending and posterolateral branches (Figure 19-5 and Video 19-3). The right coronary artery appeared to have reduced distal flow; ST-segment elevation was apparent on the monitored leads, and the patient reported severe substernal chest pain.

FIGURE 19-4 Angiogram obtained following stenting of the left anterior descending artery.

FIGURE 19-5 Retention of contrast is observed in the midportion of the right coronary artery. The previously placed Amplatz guide catheter created an extensive dissection of the proximal and midportion of this artery, leading to abrupt vessel closure. The extent of coronary calcification can be appreciated on this image.

Fortunately, the 0.014 inch guidewire entered the true lumen distally and the physician was able to position a bare-metal stent, successfully sealing the distal extent of the dissection. Additional stents were placed in the midsection, successfully restoring flow to the distal right coronary artery and eliminating the patient’s chest discomfort and ST-segment changes. A substantial dissection remained in the proximal segment (Video 19-4). While deploying a stent in the proximal segment, the operator noted staining of the aortic cusp, suggesting that the dissection had propagated to the aorta (Figure 19-6). A final stent was placed to cover the ostium. The final angiographic result was excellent, but a large arc of contrast retention was noted in the aortic cusp (Figure 19-7 and Videos 19-5, 19-6). The patient remained asymptomatic except for mild residual chest discomfort, and suffered no hemodynamic consequences. Repeat angiography 15 minutes later showed patency of the artery but persistent contrast staining in the aorta (Figure 19-8).

FIGURE 19-6 A guidewire was successfully positioned in the true lumen, and stenting of the dissection successfully restored patency of the vessel. However, contrast retention now appeared in the aortic cusp, suggesting extension of the dissection into the aorta (arrow).

FIGURE 19-7 Final angiographic result obtained after stenting to the ostium of the right coronary artery. Retention of contrast within the aortic cusp remained present (arrow).

FIGURE 19-8 Persistent retention of contrast within the aorta.

Postprocedural course

The patient was observed overnight in an intensive care unit. She remained free of symptoms and was discharged on the second day postprocedure. One week later, she was admitted with atypical chest pain occurring at rest that was judged by her physicians to be noncardiac in nature. This event was not associated with electrocardiographic changes or biomarker release; however, the uncertainty related to the natural history of her complex intervention the week before led to a repeat coronary angiogram. This showed wide patency of the stents in the left anterior descending and right coronary arteries. Upon injection of the right coronary artery, the previously observed retention of contrast in the aortic cusp was no longer apparent (Videos 19-7, 19-8).

Discussion

Coronary artery dissection is one of the most commonly occurring complications of percutaneous coronary intervention. Most commonly caused by direct barotrauma from the balloon or stent, arterial dissection may also be created by the guidewire or from an injury created by a guide catheter. Most dissections are focal and limited to the site of the injury; rarely, they extend and propagate from the original site of injury, affecting much more of the artery. The term “spiral dissection” is often used to describe a dissection that spreads from the site of the original intimal tear and extends the length of the artery. Usually, dissections propagate in the direction of arterial blood flow. Thus, they typically extend distal to the site of the initial injury; it is very unusual for a dissection to propagate proximally.

In this case, the operator anticipated the need for greater backup and chose an aggressive guide catheter. While these guides help accomplish a difficult intervention, they may engage traumatically and disrupt the intimal lining. Amplatz guides, in particular, have a tendency to engage suddenly with a lunging motion and thus have a greater risk of a dissection. This is particularly true if there is proximal disease, as evidenced by the present case.

The development of an aortic dissection complicating a coronary dissection is very rare. A review of iatrogenic aortic dissection due to catheterization or coronary intervention found 9 cases out of 43,143 catheterizations (which included 20,475 coronary interventions) for an incidence of 0.02%.¹ In this largest series to date, the authors described three types of dissection. Type I involved only the aortic cusp, similar to the example shown in this case. Type II involved the aortic cusp and extended up the aorta less than 40 mm, and Type III extended up the aorta greater than 40 mm. Similar to the case described here, all 9 events reported in this series involved the right coronary artery; the authors also comment that, of the 17 previously reported cases in the literature, 15 involved arose from a dissection in the right coronary artery. Also of note, the authors found that 44% of cases involved the use of an Amplatz catheter. Outcomes were excellent for Type I and II dissections but were poor for Type III dissections. Thus, if the aorta is involved in a limited manner, then optimal management consists of stenting of the dissection at its entry. Extensive involvement of the aorta (greater than 40 mm up the aorta), may require surgical intervention.