Management of Aortic Stenosis: Is Cardiac Catheterization Necessary? Pravin M. Shah,

MD,

and Bruce M. Graham,

he clinical decision-making for surgical treatment of aortic stenosisin adults rests largely on ( 1) severity of stenosis and (2) presence of symptoms. In general, a truly asymptomatic patient is rarely subjected to aortic valve replacement, since the risk and morbidity of surgery appear to be greater than the risk of sudden death. On the other hand, development of even mild symptoms in a patient with critical aortic stenosis (aortic valve area 10.75 cm2) calls for an early, if not urgent, valve replacement. Those with an aortic valve area >l .O cm2 (i.e., mild or moderate severity) do not require valve surgery, whereas those with severebut not critical (valve area from 0.76 to 1.0 cm2) stenosesare evaluated individually for other medical and psychosocialfactors. Thus, a patient in the latter group with associated significant coronary artery diseaseor other valvular diseasemay benefit from aortic valve replacement at the time of surgery for his other condition. The advent of continuous-wave Doppler methods in the early 1980spermitted accurate noninvasive quantitation of transvalvular pressure gradients. In 1985, the senior author (PMS), as part of a presentation at the Controversies in Cardiology segment of the Annual Scientific Sessionof the American College of Cardiology, predicted that cardiac catheterization for hemodynamic assessmentof aortic stenosiswould eventually be unnecessaryin >90% of patients. Subsequentdevelopment of newer approaches(e.g., use of the continuity equation) has permitted accurate quantitation of aortic valve area. It is thus practical to obtain accurate determination of peak and mean gradients and of aortic valve area as well as of associatedvalvular lesions and of left ventricular function from Doppler echocardiography.‘s2 Thus, in a symptomatic patient, with all this information, one should be able to make a clinical management decision relative to a need for valve replacement. The results of a report by Galan et aL3 which appears in this issueof The American Journal of Cardiologv, support these expectations on the basis of 510

T

From the Loma Linda University Medical Center, Loma Linda, California and the University of Missouri Hospitals and Clinics, Columbia, Missouri. Manuscript received December 3 1,1990, and accepted January 3,199l.

MD

consecutivepatients referred to their echocardiography laboratory for evaluation of suspected aortic stenosis over a 4-year period. The echo-Doppler examinations were considered adequate for diagnosis in 98% of patients. Their observationssuggestthat a peak velocity of 24.5 m/s (equivalent to a maximal peak gradient of > 8 1 mm Hg) is always associatedwith critical aortic stenosis.Likewise, a peak velocity of 52.5 m/s (equivalent to a peak gradient of 125 mm Hg) is always associatedwith noncritical stenosis.When Doppler data were correlated with treatment outcome (i.e., clinical management), aortic valve replacement or balloon valvuloplasty was performed in 109 of 160 patients diagnosedas having critical stenosis.Medical treatment was recommendedin 51 patients; reasonswhy were asymptomatic state, medical contraindications, patient refusal and advancedage. Thirty-five patients with noncritical stenosis(aortic valve area >0.75 cm2) underwent valve replacement, 15 for severe stenosis (valve area by Doppler between0.76 and 0.80 cm2), and 20 for associated lesionsrequiring surgery. Importantly, it should be emphasizedthat of the 238 patients with both Doppler and catheterization data available, the overall agreement between the 2 tests in distinguishing critical from noncritical stenosiswas 96%. Kegel et al4 reviewed our experiencesat Loma Linda University Medical Center with 93 patients who had adequateecho-Doppler studies and who had undergone cardiac catheterization to determine the adequacy of noninvasive methods for accurate decision-making about valve replacement. The echo-Doppler studies were reviewed by an experienced echocardiographer, who made a recommendation for or against valve replacement without knowledge of the actual outcome. Theserecommendationswere comparedwith those rendered by the attending cardiologist after cardiac catheterization. The 2 decisionswere concordant in 95% of cases.As in the current study, the best single parameter that separated patients requiring surgery from those who did not was peak jet velocity. All patients with a peak velocity >4.0 m/s required valve replacement and, likewise, none among those with a peak velocity 0.50 are probably not candidates for valve surgery. If these patients have symptomsof severeaortic stenosis, they also should undergo hemodynamic

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THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 67

studies (cardiac catheterization) for additional conlirmation. (8) Those with a peak jet velocity between 3.0 and 3.5 m/s and with a left ventricular ejection fraction 40 years old with calcific aortic stenosiswho have sufficient cusp mobility to show cusp separationby M-mode echo tracing of > 1.3 cm nearly always have a noncritically mild to moderately severestenosis. It is clear from these recommendationsthat cardiac catheterization is required for making a decision regarding a need for surgical intervention in only a small subset of patients. Most, if not all, adult patients >40 years old will require selective coronary arteriography before surgery. However, the cost and morbidity of a detailed hemodynamic evaluation by cardiac catheterization may safely be avoided. The economic impact of such a practice would be substantial and without a negative impact on patient care. REFERENCES 1. Zoghbi WA, Farmer KL, Soto JG, Nelson JG, Quinones MA. Accurate noninvasivequantification of stenoticaortic valve area by Doppler echocardiography. Circulation 1986;13:452-459. 2. Curie PJ, Seward JP, Reeder GS, Vlietstra RE, BresnahanDR. Bresnahan JF, Smith HC, Hagler DJ, Tajik JA. Continuouswave Doppler echocardiographic assessment of severity of calcitic aortic stenosis:a simultaneousDoppler catheter correlative study in 100 adult patients. Circulation 1985;71:1162-1169. 3. Galan A, Zoghbi WA, Quifiones MA. Determination of severity of valvular aortic stenosisby Doppler echocardiographyand relation of findings to clinical outcomeand agreementwith hemodynamicmeasurementsdeterminedat cardiac catheterization. Am J Cardiol 1991;67:1007-1012. 4. Kegal J, Graham B, Bansal R, Shah P. The role of echo/Doppler in clinical decisions regarding valve replacement in aortic stenosis (abstr). Clin Res 1989;37:27OA.