Cath Lab Digest - April 2008 - (Page 14)

14 ASK THE CLINICAL INSTRUCTOR APRIL 2008 Continued from page 1 Ask the Clinical Instructor Questions are answered by: Todd Ginapp, EMT-P, RCIS, FSICP Due to limitation in space, we will break our discussion into three parts. We will discuss aortic valve analysis in this month’s Part I column, and reserve the mitral valve analysis for next month. The month following that, we will briefly address a question on how stenotic valves are managed in the cath lab. Regardless of which valve is under examination, there are a couple of “absolutes” that we need to remember during our exercises: 1. To analyze a valve, you must know the pressure on each side of the valve. 2. Tricuspid and mitral valves are closed during systole and open during diastole. 3. Aortic and pulmonary valves are open during systole and closed during diastole. 4. Valves open and close due to pressure differences on either side. 5. Stenosis shows when valves are open. 6. Regurgitation shows when valves are closed. There are a few ways to analyze the patency of the aortic valve. While there are many different ways to get to the end result, following are the more common procedures. As with many methodologies that we have discussed in the past, each physician will have his or her own preferences and opinions on how these procedures are to be completed. Figure 2. With the catheter drawn back from the left ventricle to the aorta, we can see the transition line and that there is not a gradient. Left Ventricle to Femoral Sheath Comparison A pressure is obtained from the ventricle and also from the femoral sheath. It can be done separately or simultaneously, with the use of 2 transducers. However, because of peripheral amplification and delay, this method may bring the least reliable results. If a catheter is already Figure 3. One issue that can occur is when the pigtail catheter is not completely drawn out of the left ventricle (LV), and a couple of the holes at the distal end of the catheter remain in the LV, while the proximal holes are in the aorta. This gives us a ‘mixed’ reading. Withdrawing the catheter back across the valve so nothing remains in the LV is the standard approach. in the ventricle, the next procedure may be more appropriate. Dual Lumen Catheter There are a few companies that make a dual-lumen pigtail catheter. The Langston Dual-Lumen Pigtail catheter (Vascular Solutions, Inc., Minneapolis, MN), for example, is essentially a large catheter (6Fr) with a smaller catheter (4Fr) integrated within. There are ports on the proximal end of the catheter that can run to a transducer, and ports on the distal part of the catheter that are just like a pigtail catheter and can also be attached to a transducer. This process allows for both ventricular and aortic pressures to be analyzed at the same time without delay. Left Ventricle to Aorta Pullback This is the most common method for valve analysis in the cath lab. After a left ventriculogram, the catheter can be pulled back sharply into the aorta. Staff would then look at the peak-to-peak comparisons to see if there is a difference (gradient) between the two. A problem can occur when a valve is potentially bad and the orifice of the valve can be very small, which can make the passage of a wire and catheter very difficult and time-consuming. Figure 1. In this procedure, a catheter is in the left ventricle (LV) and another transducer is simultaneously connected to the sheath that is in the femoral artery. Notice there is approximately a 70-80mmHg gradient between the two. However, we cannot appreciate any peripheral amplification that may be occurring in the distal circulation. This reading, however, would direct us to the need for a more detailed and accurate method of measuring the gradient.

Table of Contents Feed for the Digital Edition of Cath Lab Digest - April 2008

Cath Lab Digest - April 2008 Kaiser San Rafael Medical Center Orbital Atherectomy: A New Treatment for Complex Peripheral Arterial Disease Ask the Clinical Instructor: A Q&A Column for Those New to the Cath Lab Contents Clinical Editor’s Corner CEU Education Center The Missing Link in STEMI Interventions — Thrombus Aspiration during Primary Percutaneous Coronary Intervention Predicting Stent Thrombosis Using A Clinical Risk Score Use of a New Guidewire: The Tigerwire Should I Stay or Should I Go? Weighing Options for New Opportunities Navigating Tortuous Coronary Sinus Anatomy Using a Bipolar Lead The National Society of Radiology Practitioner Assistants (NSRPA) Holds 9th Annual Educational Conference For Medical Imaging Physician Extenders and Mid-Level Healthcare Providers Cath Lab & Beyond: A Meeting Update The Ten-Minute Interview with… Dale Hansen RT, CVT Sometimes, You Just Know Twin Circumflex Arteries: A Rare Coronary Artery Anomaly What Do You Think? Meetings Calendar News from the American College of Cardiology (ACC) Scientific Session and the Society of Cardiovascular Angiography & Interventions (SCAI) Annual Scientific Sessions in Partnership with the ACC i2 Summit Clinical & Industry News Cath Laughs Classifieds Advertisers Index

Cath Lab Digest - April 2008

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