Cath Lab Digest

The nitrogen tank is hooked up to the back side of the console. Once the tank is hooked up, the wheel of the on/off valve is turned on (to the right). The tank should show a pi of 90 to 110, or be in the green. The amount of gas available in the tank should always be checked prior to the procedure; 500 pi is the lowest acceptable range to begin a procedure. If the tank is at or slightly about 500 pi the circulating nurse should pay special attention to make sure the tank does not run out. A pi of 750 or greater should not warrant close monitoring of nitrogen level.

Specific Nursing Considerations

A pressure bag will be needed to infuse a flush solution through the Rotablator device. The pressurized flush allows for rapid lubrication and cooling of the burr, preventing it from overheating during the operation.

Coronary vasospasm as a result of the high-speed burr spinning inside the artery has led to the development of specific flush recipes that are added to the pressure bag. Medications included in such recipes are nitroglycerin, verapamil and heparin. various doses can be used and tend to vary by institution or physician. Our institution most frequently uses the following:

500 cc normal saline
1000 units heparin
2 mg nitroglycerin
5 mg verapamil

It is believed by many physicians that adding these specific medications may aid in the reduction of coronary vasospasm during the procedure. ⁶

A nitroglycerin cup and syringe should always be on the sterile tray when a rotational atherectomy is being performed. Injections of 100 to 200 ug of nitroglycerin are frequently given for coronary vasospasm. Verapamil and adenosine may also be injected, and they should always be readily available.

The monitoring nurse/technician should pay close attention to the ECG monitor and blood pressure during each rota run. Hypotension, bradycardia, and short runs of asystole and ventricular tachycardia are commonly seen during the procedure. We recommend having a dopamine drip on standby drawn up to the following calculation: 5 ug/kg per minute.

A temporary pacer, wire and cable should always be kept in the room anticipation of any rhythm problems. The physician may elect to place a temporary pacer prior to the procedure in high-risk patients, especially those undergoing a procedure involving the right coronary artery.

Cardiac enzymes should be ordered on all patients post-procedure to rule out the possibility of a non Q-wave myocardial infarction. Rotational atherectomies carry a higher risk of procedural-induced non Q-wave myocardial infarctions than do angioplasties. It is believed that the higher risk is due to the debulking of the plaque, producing small embolic particles. ⁵

An emergency cart equipped with a defibrillator, intra-aortic balloon pump kit, and appropriate emergency medications should be readily available in the room. Rotational atherectomy carries a small risk of cardiac arrest, as do all coronary interventions. It is therefore a good idea to be prepared for such an event. Having a balloon pump on standby in the room is also a good idea. Placing the balloon pump leads on the patient prior to the procedure as well as ensuring that the pump works should be standard nursing practice. This will allow for easy access in the event that extra cardiac support is needed during the procedure.

One should also be prepared for the rare complication of cardiac tamponade as a result of coronary perforation. Having a pericardiocentesis tray available in the cardiac catheter laboratory will allow for rapid treatment of this complication.

Indications

Rotational atherectomy is indicated for discrete, complex lesions. It is also appropriate for lesions that are calcified, ostial in origin, or thought to be inappropriate for dilatation via balloon angioplasty, due to their fibrocalcific nature. It is also quite effective in some native vessels in which restenosis has occurred after PTCA. ⁵

Contraindications

Rotational atherectomy is not recommended when a lesion contains thrombus. Thrombotic lesions should be treated with balloons, stents, or thrombolytics and allowed a 2- to 4-week healing period prior to performing rotational atherectomy. It is also contraindicated for lesions within saphenous vein grafts. This is because of the potential risk of distal embolization and decreased or absent flow. Lesions at the anastomoses site, however, have been successfully treated with rotational atherectomy. ⁵

Complications

The most frequently seen complications associated with rotational atherectomy include intimal dissection, distal artery spasm, perforation, acute target vessel closure, and non Q-wave myocardial infarction. ^3,6

If there is a drop in speed of the Rotablator of 5000 rpm or more, the risk of dissection or no-reflow due to distal embolization of large particles increases. The smaller burrs (<=2 mm) safely operate at 180,000 rpm, while burrs larger than 2 mm should have speeds of 160,000 rpm or higher to minimize the threat of dissection or large-particle embolization. A strip recorder can be attached to the Rotablator console to closely monitor for excessive drops in rpm. ^2,6

The first line of treatment for intimal dissection is usually adjunctive balloon angioplasty of the affect artery. This is done in an attempt to tack up the affected artery. The physician may also elect to treat the patient with heparin for several hours after the procedure. In the event that balloon tacking is not achieved, the patient may need bypass surgery.