Cath Lab Digest - September 2007 - (Page 6)

6 CLINICAL EDITOR’S CORNER SEPTEMBER 2007 exchange for the pigtail catheter. 7) If this technique also fails, then try the multiplicity of different catheters which have had a reported success for difficult aortic valve crossings and 8) if absolutely necessary, perform transseptal catheterization and obtain the valve gradient. Crossing the aortic valve also requires some heparin to prevent small thrombi from forming on the guidewire during the potentially prolonged wire exposure during the manipulations to cross the valve. Should the need for heparin remain if the valve can be crossed within the first 30 seconds of the attempt? No one can know in advance how long wire crossing will take. Obviously this issue is important in any patient with a potential for bleeding and in aortic stenosis patients with gastrointestinal arteriovenous (GI A-V) malformations, this issue can be critical. In summary, it is my view that if the echocardiogram can provide precise, accurate, reproducible and highquality, high-confidence information, then crossing the aortic valve is relatively superfluous. This would also apply for any routine catheterization, since left ventricular function can readily be assessed by echo and the importance of left ventricular end diastolic pressure (LVEDP) has minimal contribution to the decisionmaking for most patients. However, in the patient with aortic stenosis in whom there is a question about the adequacy of the noninvasive testing, certainly retrograde cannulation of the aortic valve is important and for any patient with discordant findings, a true transvalvular gradient is the standard of care. The decision for aortic valve replacement based on echocardiography alone has been questioned by some with an experience where the echocardiogram has registered mitral regurgitation and the finding has been confused with aortic stenosis. Thus, the decision remains patient-specific, echocardiographer-specific and hemodynamic operator-specific as to whether we should cross the valve or not. The bottom line is that a really good echocardiogram will obviate the need to cross the stenotic aortic valve. ■ Class I indications: (Experts agree procedure is indicated) 1. Coronary angiography is recommended before aortic valve replacement in patients with aortic stenosis at risk for coronary artery disease (level of evidence, B). 2. Cardiac catheterization for hemodynamic measurement is recommended for assessment of severity of aortic stenosis in symptomatic patients where noninvasive tests are inconclusive or when there is a discrepancy between the noninvasive test and clinical findings regarding the severity of aortic stenosis (level C). 3. Coronary angiography is recommended before aortic valve replacement in patients with aortic stenosis for whom a pulmonary autograft (Ross procedure) is contemplated and if the origin of coronary arteries was not identified by noninvasive testing (level C). The major issue with regard to the need to cross the aortic valve is, how reliable is your echocardiography data? Does your echo satisfy the guidelines’ conclusion that “non-invasive tests are adequate and concordant with clinical findings”? If this is not the case, then the severity of the aortic stenosis must be obtained by transvalvular gradient measurement with an accurate cardiac output computation for valve area. Thus, it is really the echo that makes the need to cross the valve a problem. Excellent echo, no problem. The question for the crossing of the stenotic aortic valve thus remains one of confidence in the data obtained during echocardiography to obviate the need for left ventricular functional assessment and translesional gradient. Remember that there are several other pieces of information that can be acquired during cardiac catheterization in patients with aortic stenosis. In addition to documenting the severity of aortic obstruction, we could: 1. Single arterial puncture with a pressure pullback. 2. A single arterial puncture with a peripheral arterial sheath, one size bigger than the pigtail catheter commonly employed. 3. Two arterial punctures, with one catheter positioned just above the valve and one across the valve. 4. A venous transseptal approach to the left ventricle with an arterial pressure catheter positioned above the aortic valve. 5. Single arterial puncture with a dual lumen catheter, either fluid-filled or high-fidelity micromanometer. 6. Single lumen catheter with a fluid lumen and pressure guidewire. All of the above, with the exception of the transseptal technique, require retrograde catheterization. In my view, without a personal appreciation of the echocardiogram, I favor crossing the aortic valve with all caution, use of heparin, limiting wire time and selection of favorable Class III indications to the performance of cardiac catheterization: (Experts agree procedure provides no benefit or may be harmful) 1. Cardiac catheterization for hemodynamic measurement is not recommended for the assessment of severity of aortic stenosis before aortic valve replacement when noninvasive tests are adequate and concordant with clinical findings (level C). 2. Cardiac catheterization for hemodynamic measurement is not recommended for the assessment of left ventricular function and severity of aortic stenosis in asymptomatic patients (level C). These recommendations present a change to the standard approach for cardiac catheterization in the aortic stenosis patient. In years past and in most training programs, it was considered a normal component of cardiac catheterization for the complete assessment of aortic stenosis to include right and left heart cath, with retrograde cannulation of the left ventricle for gradient measurement and left ventriculography. There are alternatives to retrograde cannulation, such as transseptal catheterization, should a precise gradient be required. If the echocardiogram can provide precise, accurate, reproducible and highquality, high-confidence information, then crossing the aortic valve is relatively superfluous. • Obtain the status of left ventricular function and the true location of a left ventricular-aortic gradient since, in some patients, subvalvular or intraventricular gradients can be confused with aortic stenosis; • Identify additional associated valve disease such mitral regurgitation, mitral stenosis or aortic insufficiency which was not clarified by echocardiography. Of course, the status of coronary arteries must be established, but may be soon assessed by noninvasive visualization through computerized tomographic coronary arteriography. To review, the techniques to obtain hemodynamic pressure gradients in aortic stenosis include: catheters for quick crossing success. A routine approach would involve 1) a right heart catheterization with cardiac output and oxygen saturations, 2) a brief attempt to cross the valve with a pigtail and 0.038” straight guidewire. If successful, proceed to simultaneous hemodynamic measurements followed by low-volume left ventriculogram (LV gram). 3) If unsuccessful, proceed to left coronary angiography and then, 4) using the left Judkin’s catheter and a 0.038” straight wire, attempt to cross the aortic valve. Then, with a 0.038” long J wire, exchange the Judkin’s catheter for a pigtail catheter. If this fails, 5) perform right coronary angiography and using the right Judkin’s catheter, 6) attempt to cross the valve and then Reference 1. Omran H, Schmidt H, Hackenbroch M, et al. Silent and apparent cerebral embolism after retrograde catheterisation of the aortic valve in valvular stenosis: A prospective, randomised study. Lancet 2003;361:1241–1246.

Table of Contents Feed for the Digital Edition of Cath Lab Digest - September 2007

St. Dominic Hospital The Genous Bio-engineered R Stent Percutaneous Treatment of Peripheral Arterial Chronic Total Occlusions: Device Options and Clinical Outcomes Contents Clinical Editor’s Corner Percutaneous Revascularization of Peripheral Chronic Total Occlusion — Which Patients, Why, and How? Myocardial Infarction and Syncope: A Manifestation of the “Raynaud-Prinzmetal Syndrome”? Essential Technical Components of the Transradial Approach If You Build It, Will They Come? Evidence-Based Medicine with Drug-Eluting Stents Back to School: The Value of Education in Cardiovascular Services The ACVP Standards and Competencies: Are You Using Them Effectively? What Do You Think? My Experience with Fibromuscular Dysplasia and Stroke A Brief Review of Fibromuscular Dysplasia Letter to the Editor A Look at On-the-Job Training: Perceptions, Reality and Our Profession Doing the Wave: Inventory Management with RFID The Ten-Minute Interview with… Paul Pinsker, RCIS CLD’s Annual Salary Survey Harrisburg Area Community College Volunteer Survey CEU Education Center SICP* Section Ask the Clinical Instructor: A Q&A Column for Those New to the Cath Lab Clinical & Industry News

Cath Lab Digest - September 2007

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