David -
Don't know if you've seen this diagram; I've posted it elsewhere in the VR.com forums. Note that another key measurement is cardiac ejection fraction (discussed in the excerpt below.)
It seems like you're progressing pretty quickly. I would say vigilance is in order. Please do not skip or delay scheduled follow-up appts! There is no "standard" timeline for progression of AVR. Everyone is different.
I've posted links to pubs that you may find useful.
My personal opinion is that you want the best heart surgeon available to you (one that specializes in valve repair, not just a CT surgeon that dabbles in them.) I traveled for my surgery. The prospect of travel was initially very daunting, but a little planning can overcome the challenges. I ignored the local surgeon recommendations of my cardio. After the op, he was impressed with my 1 year follow up echo: "wow, they didn't **** up your heart at all," and acknowledged that the extent to which a surgical team manhandles your heart (or doesn't) is an important determinant of post-op complications like a-fib and contraction abnormalities.
Best of luck.
http://www.acc.org/clinical/guidelines/valvular/3205p149.pdf
http://www.acc.org/clinical/guidelines/valvular/PValvulr.pdf
h. Indications for Aortic Valve Replacement. In patients with pure, chronic AR, AVR should be considered only if AR is severe. Patients with only mild AR are not candidates for valve replacement, and if such patients have symptoms or LV dysfunction, other etiologies should be considered, such as CAD, hypertension, or cardiomyopathic processes. If the severity of AR is uncertain after a review of clinical and echocardiographic data, additional information may be needed, such as invasive hemodynamic and angiographic data. The following discussion applies only to those patients with pure, severe AR.
(1) SYMPTOMATIC PATIENTS WITH NORMAL LV SYSTOLIC FUNCTION. AVR is indicated in patients with normal systolic function (defined as ejection fraction >0.50 at rest) who have NYHA functional Class III or IV symptoms. Patients with Canadian Heart Association functional Class II to IV angina pectoris should also be considered for surgery. In many patients with NYHA functional Class II dyspnea, the etiology of symptoms is often unclear, and clinical judgment is required. Patients with well-compensated AR often have chronic mild dyspnea or fatigue, and it may be difficult to differentiate the effects of deconditioning or aging from true cardiac symptoms. In such patients, exercise testing may be valuable. If the etiology of these mild symptoms is uncertain and they are not severe enough to interfere with the patient's lifestyle, a period of observation may be reasonable. However, new onset of mild dyspnea has different implications in severe AR, especially in patients with increasing LV chamber size or evidence of declining LV systolic function into the low normal range. Thus, even if patients have not achieved the threshold values of LV size and function recommended for surgery in asymptomatic patients, development of mild symptoms is an indication for operation in a patient who is nearing these values.
(2) SYMPTOMATIC PATIENTS WITH LV DYSFUNCTION. Patients with NYHA functional Class II, III, or IV symptoms and with mild to moderate LV systolic dysfunction (ejection fraction 0.25 to 0.49) should undergo AVR. Patients with functional Class IV symptoms have worse postoperative survival rates and lower likelihood of recovery of systolic function compared with patients with less severe symptoms (170,176,177,179), but AVR will improve ventricular loading conditions and expedite subsequent management of LV dysfunction (163).
Symptomatic patients with advanced LV dysfunction (ejection fraction <0.25 and/or end-systolic dimension >60 mm) present difficult management issues. Some patients will manifest meaningful recovery of LV function after operation, but many will have developed irreversible myocardial changes. The mortality associated with valve replacement approaches 10%, and postoperative mortality over the subsequent few years is high. Valve replacement should be considered more strongly in patients with NYHA functional Class II and III symptoms, especially if (1) symptoms and evidence of LV dysfunction are of recent onset and (2) intensive short-term therapy with vasodilators, diuretics, and/or intravenous positive inotropic agents results in substantial improvement in hemodynamics or systolic function. However, even in patients with NYHA functional Class IV symptoms and ejection fraction <0.25, the high risks associated with AVR and subsequent medical management of LV dysfunction are usually a better alternative than the higher risks of long-term medical management alone (241).
(3) ASYMPTOMATIC PATIENTS. AVR in asymptomatic patients remains a controversial topic, but it is generally agreed (158,242-246) that valve replacement is indicated in patients with LV systolic dysfunction. As noted previously, for the purposes of these guidelines, LV systolic dysfunction is defined as an ejection fraction below normal at rest. The lower limit of normal will be assumed to be 0.50, realizing that this lower limit is technique dependent and may vary among institutions. The committee also realizes that there may be variability in any given measured LV dimension or ejection fraction. Therefore, the committee recommends that 2 consecutive measurements be obtained before proceeding with a decision to recommend surgery in the asymptomatic patient. These consecutive measurements could be obtained with the same test repeated in a short time period (for example, a second echocardiogram after an initial echocardiogram) or with a separate independent test (for example, a radionuclide ventriculogram or a contrast left ventriculogram after an initial echocardiogram).
Valve replacement is also recommended in patients with severe LV dilatation (end-diastolic dimension >75 mm or end-systolic dimension >55 mm), even if ejection fraction is normal. The majority of patients with this degree of dilatation will have already developed systolic dysfunction because of afterload mismatch and will thus be candidates for valve replacement on the basis of the depressed ejection fraction. The elevated end-systolic dimension in this regard is often a surrogate for systolic dysfunction. The relatively small number of asymptomatic patients with preserved systolic function despite severe increases in end-systolic and end-diastolic chamber size should be considered for surgery, as they appear to represent a high risk group with an increased incidence of sudden death (193,247), and the results of valve replacement in such patients have thus far been excellent (189). In contrast, postoperative mortality is considerable once patients with severe LV dilatation develop symptoms and/or LV systolic dysfunction (189). The data regarding the risk of sudden death and postoperative outcome with severe LV dilatation have been developed with an LV end-diastolic dimension >80 mm, but the committee recommends surgery before the left ventricle achieves this degree of dilatation and recommends AVR for patients with LV end-diastolic dimension >75 mm.
Patients with severe AR in whom the degree of dilatation has not reached but is approaching these threshold values (for example, LV end-diastolic dimension of 70 to 75 mm or end-systolic dimension of 50 to 55 mm) should be followed carefully with frequent echocardiograms every 4 to 6 months, as noted previously (Figure 2). In addition, it is reasonable to recommend AVR in such patients if there is evidence of declining exercise tolerance or abnormal hemodynamic responses to exercise, for example, an increase in pulmonary artery wedge pressure >25 mm Hg with exercise.
Several patient subgroups develop LV systolic dysfunction with less marked LV dilatation than observed in the majority of patients with uncomplicated AR. These include patients with long-standing hypertension in whom the pressure-overloaded ventricle has reduced compliance and a limited potential to increase its chamber size; patients with concomitant CAD, in whom myocardial ischemia may develop with increasing myocardial wall stress, resulting in ventricular dysfunction; and patients with concomitant MS, in whom the left ventricle will not dilate to the same extent as in patients with pure AR (248). In such patients, it is particularly important that systolic function and not merely systolic dimension be monitored. Women also tend to develop symptoms and/or LV dysfunction with less LV dilatation than men (249); this appears to be related to body size as these differences are not apparent when LV dimensions are corrected for body surface area. Hence, LV dimensions alone may be misleading in small patients of either gender, and the threshold values of end-diastolic and end-systolic dimension recommended above for AVR in asymptomatic patients (75 mm and 55 mm, respectively) may need to be reduced in such patients. There are no data with which to derive guidelines for LV dimensions corrected for body size, and clinical judgment is required.
A decrease in ejection fraction during exercise should not be used as an indication for AVR in asymptomatic patients with normal systolic function at rest, because the exercise ejection fraction response is multifactorial and the strength of evidence is limited. The ejection fraction response to exercise has not proved to have independent prognostic value in patients undergoing surgery (179). The change in ejection fraction with exercise is a relatively nonspecific response related to both severity of volume load (193,200-202) and exercise-induced changes in preload and peripheral resistance (203) that develop early in the natural history of AR. Valve replacement should also not be recommended in asymptomatic patients with normal systolic function merely because of evidence of LV dilatation as long as the dilatation is not severe (end-diastolic dimension <75 mm or end-systolic dimension <55 mm).
Patients who demonstrate progression of LV dilatation or progressive decline in ejection fraction on serial studies represent a higher-risk group who require careful monitoring (193), but such patients often reach a new steady state and may do well for extended periods of time. Hence, valve replacement is not recommended until the threshold values noted above are reached or symptoms or LV systolic dysfunction develop.
