Canadian Neighbor Pharmacy: Functional Class and Cardiac Performance in Patients with Chronic Aortic Insufficiency

25 Sep
2015

heart failureThe natural history of chronic aortic insufficiency is a continuum marked by a prolonged initial plateau phase during which the patient is relatively stable, and a later phase of progressive deterioration in left ventricular performance. Once the signs and symptoms of heart failure appear, chronic irreversible changes in left ventricular function may have occurred. Since the likelihood of improvement in left ventricular function after aortic valve replacement is less certain once this point has been reached, current practice is to intervene surgically prior to the onset of substantial deterioration of the left ventricle. However, the stable plateau phase may persist for decades and surgery should not be performed too early since that would subject the patient to premature risk from the operative procedure, as well as from complications of the prosthesis itself.

In deciding how to proceed in the management of patients with chronic aortic insufficiency, the clinician often relies heavily upon his assessment of cardiac symptoms. However, experience with cardiac patients has shown that symptoms do not always reflect underlying cardiac function. In this report we compare the pre-catheterization evaluation of cardiac symptoms with the results of cardiac catheterization and angiography in a large group of patients with isolated chronic aortic insufficiency in order to evaluate the value of cardiac symptoms in predicting left ventricular function.

Methods

The hospital records and catheterization data from a group of 75 consecutive patients with chronic isolated aortic insufficiency who were studied at our institution were reviewed. These patients were referred for cardiac catheterization based on history, physical examination, and the results of noninvasive tests which suggested the presence of clinically important aortic insufficiency. Patients were included in the study only if they met the following criteria: clinically stable at the time of study; age greater than 18 years; aortic insufficiency known to be present at least 18 months. The study included complete right- and left-heart catheterization and left ventriculography and aortic insufficiency was demonstrated to be the only significant valvular lesion at the time of catheterization. Patients with an aortic valve gradient less than 25 mm Hg and those with mitral regurgitation graded trivial or mild by angiography were included in the study. Patients with a history of angina or myocardial infarction, pathologic Q waves on 12-lead electrocardiogram or segmental wall motion abnormalities by angiography were excluded.

The 75 patients (57 men and 18 women) who fulfilled all the above criteria averaged 41 years of age (range 19-74 years). Sixty patients had no aortic valvular gradient, four had 1-10 mm Hg gradients, nine had 11-20 mm Hg gradients, and two had 21-25 mm Hg gradients. Aortic insufficiency was thought to be due to rheumatic disease in 31 patients, bicuspid valve in 13 patients, luetic disease in four patients, Marfans syndrome in four patients, aortic dissection in three patients, rheumatoid arthritis in two patients, and infective endocarditis in one patient. In 17 patients the etiology was unknown. Do you like to read latest news about medicine? You are welcome on the web site of Canadian Neighbor Pharmacy.endocarditis

Symptoms were evaluated prior to catheterization by a full-time staff cardiologist in all cases. Patients were classified according to criteria suggested by the New York Heart Association. By these criteria, 17 patients were felt to be in functional class (FC) 1, 35 were in FC 2,18 in FC 3, and five in FC 4. At the time of study, 19 percent of FC 1,55 percent of FC 2, and 70 percent of FC 3-4 were receiving digoxin. In addition, no FC 1, 6 percent of FC 2, and 25 percent of FC 3-4 patients were being maintained on diuretic agents. None of the 75 patients was receiving vasodilator drugs.

All patients underwent complete right- and left-heart catheterization and left ventriculography. The methods used in our laboratory have been published previously. In all patients, hemodynamic variables were measured at rest. In 40 patients, these measurements were repeated during supine exercise using a bicycle ergometer. Exercise was begun at a load of200 kpm and increased after 4 minutes by 200 kpm until limited by symptoms of fatigue and/or dyspnea. No patient was limited by chest pain. Measurements at each worldoad were taken after 2 minutes of exercise at a time when hemodynamics were stable. Cardiac output was determined using the Fick principle at both rest and exercise. The number of actual determinations for each of the variables evaluated in this study is slightly less in all instances than the number of patients available for study. The reason for this disparity is that in some patients not all hemodynamic and angiographic measurements were obtained. In addition, some measurements were found to be technically inadequate and were not included in the study. All patients who related symptoms of chest pain or who were 40 years or older underwent coronary angiography. Of the 46 patients who had coronary angiograms performed, ten were judged to have significant coronary artery disease based on the presence of a ^50 percent diameter narrowing of at least one of the major coronary vessels.One-way analysis of variance was employed to determine if there was significant (p <.05) difference for any of the variables between the functional class groups. Patients with FC 3 and 4 assignments were considered a single group since there were only five FC 4 patients. If analysis of variance showed a significant difference, the paired f-test was employed to identify the specific differences.

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