Migratory Buckling of a Tortuous Right Coronary Artery after Stent Deployment
An Irreversible Accordion Effect
Case Report
A 79 year old Caucasian woman, with a past medical history of heavy tobacco use and small bowel resection secondary to ischemia 7 months prior, presented to emergency room with acute onset of substernal chest pressure. ECG showed normal sinus rhythm, first degree AV block. Echocardiogram showed preserved left ventricular function. Subsequent cardiac enzymes were elevated consistent with non-ST elevation myocardial infraction. Patient was treated medically with resolution of symptoms. Patient then underwent coronary angiography.
There was an 80% segmental stenosis at the proximal right coronary artery which had significant tortuosity along the proximal segment. Patient received intravenous heparin and integrilin at the beginning of the intervention. A 6F JR4 guiding catheter was used to engage the right coronary ostium. A universal guide wire was used to cross the proximal stenotic lesion without difficulty and was advanced to the distal posterolateral branch. The stenotic lesion was treated with primary deployment of a 3.5/18 mm Penta stent to a maximum pressure of 8 atmosphere.
Repeat right coronary artery angiography with the guide wire withdrawn revealed a new 70% stenotic lesion just distal to the newly deployed stent. 200 mcg of intracoronary nitroglycerin was administered. Repeat right coronary artery angiography revealed no changes. This lesion was treated with a second primary deployment of a 3.5/8 mm Penta stent to a maximum pressure of 8 atmosphere. Repeat right coronary artery angiography with a deep seated JR4 guiding catheter revealed no residual stenosis.
As the guiding catheter was withdrawn to the ostium, right coronary artery angiography with the guide wire withdrawn again showed a new 70% stenotic lesion proximal to the first stent placed.
After obtaining proper guiding catheter support, the new proximal stenotic lesion was treated with a third primary deployment of a 3.5/8 mm Penta stent to a maximum pressure of 8 atmosphere. As before, the guiding catheter was withdrawn to the ostium, right coronary artery angiography with the guide wire withdrawn again showed another new 70% stenotic lesion proximal to the third stent placed. A non-selective right coronary angiography confirmed the presence of the new proximal stenosis independent of the guiding catheter placement.
The lesion was finally treated with a fourth primary deployment of a 3.5/13 mm Penta stent to a maximum pressure of 8 atmosphere. The fourth stent covered the remaining section of the proximal right coronary artery extending to the ostium. Final right coronary artery angiography after withdrawing the guide wire showed no residual stenosis but there was significant straightening of the vessel. Patient had no chest pressure or electrographic changes during the procedure. Patient was discharged without any further complications.
Discussion
The accordion effect caused by angioplasty guidewire at the right coronary artery had previously been described (1,2). It is usually caused by mechanical alteration of the geometry and the curvature of the vessel resulting in invagination and shortening of the vessel wall. This is also referred as pseudo-narrowing (5). This phenomenon can resemble atherosclerotic stenosis of the coronary artery. Such stenosis could be flow limiting resulting in symptoms and electrocardiographic changes in a patient (3). The accordion effect could simply be relieved by the removal of the mechanical device altering the geometry of the vessel for example, a stiff angioplasty wire, a guiding catheter or an angioplasty balloon. Therefore, the proper lumen dimension and flow of the artery are restored.
In our case, the lesions discovered after the first stent deployment were the result of the accordion effect secondary to the placement of the intracoronary stent. The proximal lesions were initially masked by the deep seating of the guiding catheter which supported the proximal portion of the vessel. As the support was withdrawn, the vessel tissue buckled resulting in shifting and folding of the intimal layer of the vessel wall. Other complications of coronary intervention, for example, coronary spasm, dissection, thrombus formation, must be ruled out. Damage of the intimal layer of the coronary vessel leading to stenosis by means of platelet activation and intimal proliferation had been suggested.
Due to the inability to remove a deployed stent, the accordion effect could not be relieved in our case. Pseudo-narrowing is not responsive to vasodilators. Patient is therefore at risk for ischemia and thrombosis at the buckling site. The only therapeutic option was to deploy stents at these pseudo-narrowings. Retrospectively, we did not intend to deploy multiple intracoronary stents in the right coronary artery. Fracture of an intracoronary stent inside a tortuous artery had been reported due to repetitive bending during the cardiac cycle (7). Treatment strategy can be approached by either using multiple shorter and more flexible stents with small radius of curvature or by using longer and rigid stents to prohibit accordion effect. Straightening of the angulation of the arterial does not predict restenosis at the hinge site. However, implantation of a rigid stent at the hinge point is associated with an increased rate of restenosis (9). Changing the natural curvature of a coronary artery by stent also significantly contributes to the occurrence of major cardiac adverse events (10). Therefore, the usage of stents that minimize the change of geometry of the vessel is preferred (8).
References
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