Temporary Stenting as a Bridge to Surgery

Temporary Stenting as a Bridge to Surgery NICOLAS CHRONOS, B.Sc., Hons MRCP, RODNEY STABLES, M.A., MRCP, SIMON GIBBS, MRCP, JAN ERIK NORDREHAUG, M.D., ULRICH SIGWART, M.D., and NIGEL BULLER, B.Sc., Hons MRCP From the Royal Brompion Hospital, London, England

Abrupt occlusion of the coronary artery during PTCA is a relatively common complication. The majority of the acute occlusions occur when there is a significant dissection at the site of the balloon expansion. The use of a temporary stent, which can be expanded and collapsed intraluminally, allowing repositioning and finally removal of the device, is reported in this urticle. (J Interven Cardiol 1994;7:327-330)

Introduction The use of the bail-out devices to assist with the management of complications of percutaneous transluminal coronary angioplasty (PTCA) is becoming more frequent. Acute coronary occlusion, secondary to coronary dissection following PTCA occurs in 4.4%-7.3% of all procedures, and this can have disastrous hemodynamic effects.’ Long inflations are used to overcome the dissection and, by bringing the wall layers back into apposition, “tack back” the dissection flap. This, however, causes additional ischemia while the balloon is inflated. The rapid return of antegrade flow following the placement of an intraluminal device can salvage significant amounts of myocardium and, therefore, modify the course of the complication, allowing emergency surgery to be performed in a stable patient. Limitations with the autoperfusion balloons used to date has been that they cause complete occlusion of side branches while inflated, and in addition, only Address for reprints: Dr. Rodney Stables. Department of Interventional Cardiology, Royal Brompton National Heart & Lung Hospital, Sydney Street, London SW3 6NP. Fax: 44 71 351 8614. Submitted for publication November 17, 1993; revised for publication January 19, 1994; accepted for publication January 21, 1994.

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modest flow rates to the distal vessel can be obtained. Both of these problems are solved with the device reported below.

Case Report A 41-year-old construction worker with a 6 day history of frequent episodes of chest pain at rest was admitted to his local hospital. Further pain was accompanied by electrocardiographic ST segment depression and a diagnosis of unstable angina was made. He was treated with aspirin, atenolol, IV Nitrate, and heparin and transferred to our hospital for evaluation. He smoked 20 cigarettes per day and had a positive family history for coronary heart disease. On physical examination his blood pressure was 130/80 and his heart rate was 50 at rest. However, he was in pain and became sweaty, looked unwell, developed a marked tachycardia, and became hypotensive. His electrocardiogram when pain free showed sinus rhythm with normal axis and T-wave inversion in V2 and V3, and T-wave flattening in the lateral chest leads. Angiography was performed and revealed normal left ventricular function and a proximal, complex lesion in the left anterior descending coronary artery at the origin of a large

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CHRONOS, ET A L

Figure 1. Angiograrn showing complex lesion in LAD involving diagonal branch. Note the poststenosis aneurysm (arrowed 1.

diagonal branch. The other coronary arteries were normal (Fig. I ) . A decision was made in consultation with the surgical team to perform PTCA to this lesion. A Judkins left 4 guiding catheter was used with an 0.014-In Hi-torque floppy wire and 2.5 mm Shadow balloon. During balloon inflation (6 inflations to a maximum of 8 bar) the patient developed marked ST elevated in the anterior chest leads and became hypotensive (90/70mmHg); following deflation, these changes resolved after 1 minute. Angiography showed a marked proximal dissection at the site of the stenosis propagating into the distal left anterior descending coronary artery including the origin of the diagonal branch. Despite prolonged inflations at 8 bar for 3 minutes, there was still poor antegrade flow (TIMI 1) to the diagonal coronary artery and the left anterior descending was occluded after the diagonal branch (Fig. 2 ) . With this occlusion the patient complained of chest pain and became hypotensive (85170 rnrnHg). cool peripherally and had marked ST segment elevation in the anterior chest leads. It was decided to perform coronary artery bypass grafting, and to implant a bail-out device as a bridge to surgery. In view of the large diagonal branch of the left anterior descending coronary artery being involved. a traditional autoperfusion

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Figure 2. Angiogram showing extensive dissection (arrowed) and closure of diagonal with poor LAD flow after balloon angioplasty.

balloon was considered to be undesirable as this would cause occlusion of the diagonal branch. An RX”’ Flow Support catheter (Advanced Cardiovascular Systems, Inc., Santa Clara, CA, USA) was positioned in the left anterior descending at the bifurcation with the diagonal. When expanded, the wire mesh temporary stent allows perfusion to be maintained not only to the distal vessel, but also to side branches. This temporary stent has an integrated shaft with an expandable radio-opaque braided wire cage near the distal tip (Fig. 3). The wire cage is coated in MicroglideR coating to facilitate easy placement through the guide catheter. Radioopaque markers are located at the proximal and distal ends of the cage to allow accurate positioning within the artery. The device has a rail design shaft for rapid deployment over a 0.014-in guide-

Figure 3. Temporary expandable and collapsible braided wire slent.

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TEMPORARY STENT I N ABRUPT CLOSURE

Figure 4. Ratchet mechanism allowing expansion and collapsing of temporary stent.

wire and also includes a small flush lumen for heparinised saline. An advantage of this device is the ratchet mechanism that expands the cage to the appropriate vessel diameter. The unexpanded stent is available in 3 and 4-cm cage lengths and expands to a maximum diameter of 4 mm. As the cage width is expanded, using the ratchet device at the proximal end of the catheter (Fig. 4), the length decreases in near linear proportion. For the 3cm size, the length falls from 17 mm at 2.5 mm

diameter to 8 mm at 4-mm diameter. For the 4cm length the corresponding values are 27 mm and 15 mm respectively. This temporary stent was deployed under fluoroscopy. On expansion good angiographic flow down both the left anterior descending and the diagonal branch was achieved (Fig. 5 Arrows identify radio opaque markers at the ends of the stent). The chest pain resolved, electrocardiographic changes normalized and the blood pressure rose to preangioplasty levels. The patient was asymptomatic and was referred for emergency coronary artery bypass surgery. Since the patient was stable with the temporary stent in situ, prolonged expansion in order to treat the dissection was tried, but was unsuccessful. There was a delay of 3 hours 29 minutes experienced between the initial expansion of the temporary stent and commencing cardiopulmonary bypass. The patient was stable, able to converse with his wife and staff prior to surgery and underwent uneventful coronary artery bypass surgery. The left internal mammary artery was anastomsed to the left anterior descending coronary artery and a reverse saphenous vein graft attached to the diagonal coronary artery. The temporary stent was then collapsed and removed from the coronary circulation with the patient on cardiopulmonary bypass. The patient made an uncomplicated recovery

Figure 5. Angiograms showing flow down LAD and diagonal with temporary stent in place. Arrows demonstrate the distal end markers (radio-opaque) with the guided wire down the LAD.

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and there was no rise in the cardiac enzymes (CKMB). His electrocardiogram was similar to the preangioplasty electrocardiogram with only minor changes in the anterior chest leads. The patient was discharged home on the ninth postoperative day. At 3 months follow-up, the patient was asymptomatic, there was no evidence of any ECG changes, an echordiogram performed showed normal ventricular dimensions with reversed septa1 motion. A MUGA scan was performed, which showed normal left ventricular function with an ejection fraction of 75%. The patient was continued on aspirin and no other medication.

Discussion Acute abrupt vessel closure occurs in 4.4%-7.3% of coronary angioplasty procedures,' and may cause significant hemodynamic impairment with consequent myocardial infarction if emergency surgical revascularization is not peformed. Of relevance to this case the procedural death rate is closely associated with the presence of a large amount of myocardium at risk during the procedure.' The essence of the management of the abrupt closure is the limitation of the extent and duration of ischemia. Attempts to redilate the lesion with an oversized balloon have proved successful in 3S%-51% of cases.3 Emergency surgery carries a high risk of death ( 2 7 ~ 2 5 % and ) Q wave myocardial infarction (2 1%-70G/c).3Evidence has shown that acute implantation of coronary stent can prove effective in establishing distal coronary flow.' However, in this patient the length of the

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dissection was longer than any available implantable stent and also involved the origin of the diagonal branch of the left anterior descending coronary artery. It was, therefore felt that the patient would be best served by coronary artery bypass surgery. The implantation of this novel temporary stent allowed distal perfusion of both the left anterior descending and an important diagonal branch and enabled t h e patient to be referred in a stable condition for emergency coronary artery bypass surgery. Temporary expansion of this stent alone could, by approximating the elements of the arterial wall, prove therapeutic in a number of patients. In view of the stability of the patient, the surgeon was able to use the left internal mammary artery as a conduit, an advantage not available in all emergency procedures. The patient suffered no myocardial infarction and 3 months after PTCA. had normal left ventricular function. This device, which is currently under invesitigation, enables the patient to undergo surgical revascularization in a stable condition. It also offers an alternative to balloon autoperfusion and permanent stenting as a bridge to surgery.

References Ellis S. Roubin GS, King SB I l l , et al. Angiographic and clinical predictors of acute closure after native vessel coronary angioplasty. Circulation 1988;77:372-379. 2 . Park DD. Laramee L A , Teirstein P, et al. Major complications during PTCA: An analysis of 5,413 cases (abstract). JACC 1988;11:237. 3 . Sinclair J N . McGabe C H , Sipperly ME, et al. Predictors therapeutic options and long term outcome of abrupt reclosure. Am J Cardiol 1988;61:6lg-66g. 4. Sigwart U , Puel J, Mirkovitch V, et al. Intravascular stents to prevent occlusion and restenosis after percutaneous transluminal angioplasty. N Engl J Med 1987;316: 701 -706.

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