Valve replacement should not be performed in all asymptomatic patients with severe aortic incompetence

Usefulness of preoperative stroke volume as strong predictor of left ventricular remodeling and outcomes after aortic valve replacement in patients with severe pure aortic regurgitation

In most patients with aortic regurgitation (AR), aortic valve replacement (AVR) results in favorable left ventricular (LV) remodeling and normalization of the LV ejection fraction (EF). However, some patients with severe AR will not have favorable remodeling and their LVEF will not normalize. The goal of the present study was to determine whether remodeling and clinical outcomes after AVR could be predicted from simple preoperative echocardiographic analysis. A total of 56 consecutive patients with chronic severe pure AR who underwent AVR had preoperative (5 ± 2 days), early postoperative (5 ± 2 days), and late postoperative (328 ± 88 days) echocardiographic data retrospectively analyzed. The LV diameter, The LVEF and stroke volume (SV) were measured. The reduction in LV end-diastolic dimension decreased by 14% (from 65 ± 6 mm to 56 ± 8 mm, p <0.001) early after AVR, with an additional reduction of only 6% late after AVR. More than 2/3 of the overall reduction in end-diastolic dimension was observed the week after AVR. Forty-six patients (82%) had positive early LV remodeling, defined as a 10% reduction in the LV end-diastolic diameter 1 week after AVR. All patients with early LV remodeling had a preoperative SV of ≥97 ml, which was the best predictor of late postoperative LVEF of ≥45% (sensitivity 98% and specificity 100%). Patients with a preoperative SV of ≥97 ml had a markedly greater event-free survival rate (92% vs 13%, p <0.001) at 3 years. In conclusion, in patients undergoing AVR for chronic severe pure AR, preoperative SV is the best predictor of LV remodeling and outcomes.

Long-term survival and functional results after aortic valve replacement in asymptomatic patients with chronic severe aortic regurgitation and left ventricular dysfunction

OBJECTIVES

We examined the influence of medical treatment on the results of surgery in terms of long-term survival and functional results in patients with chronic, severe aortic regurgitation (AR).

BACKGROUND

Asymptomatic patients with AR and a reduced left ventricular ejection fraction (LVEF) are at high risk because of a higher-than-expected long-term mortality. The influence of preoperative medical therapy on the outcome after aortic valve replacement (AVR) is not well known.

METHODS

Surgery was indicated for the appearance of a reduced LVEF (<50%). At the time of AVR, there were 134 patients treated with nifedipine (group A), and 132 received no medication (group B).

RESULTS

Operative mortality was similar in the two groups (0.75% vs. 0.76%, p = NS). The LVEF normalized in all of group A, whereas it remained abnormal in 36 group B patients (28%). At 10-year follow-up, LVEF persisted higher in group A (62 +/- 5% vs. 48 +/- 4%, p < 0.001). Five-year survival was similar in the two groups (94 +/- 2% vs. 94 +/- 3%, p = NS). Group A showed a 10-year survival not different from expected and significantly higher than that in group B (85 +/- 4% vs. 78 +/- 5%, p < 0.001), which had a worse survival than expected.

CONCLUSIONS

Unloading treatment with nifedipine in AR allows one to indicate AVR at the appearance of a reduced LVEF with a low operative mortality and an optimal long-term outcome. The concept of surgical correction of AR indicated for reduced LVEF may not be applied to all patients. Indeed, in a large amount of untreated patients, a reduced LVEF preoperatively is not reversed by prompt surgery, indicating irreversible myocardial damage, and 10-year survival is worse than expected.

Chronic aortic regurgitation. Role of medical therapy and optimal timing for surgery

Aortic valve replacement should be performed once significant symptoms develop. Lacking important symptoms, operation should also be performed in patients with aortic regurgitation who manifest consistent and reproducible evidence of either LV contractile dysfunction at rest or extreme LV dilation. Noninvasive imaging techniques should play a major role in this evaluation. An important clinical decision, such as recommending aortic valve replacement in the asymptomatic patient, should not be based on a single echocardiographic or radionuclide angiographic measurement alone. When these data consistently indicate impaired contractile function at rest or extreme LV dilation on repeat measurements, however, operation is indicated in the asymptomatic patient. This strategy should reduce the likelihood of irreversible LV dysfunction in these patients and enhance long-term postoperative survival.

Optimizing timing of surgical correction in patients with severe aortic regurgitation: role of symptoms

OBJECTIVES

We sought to determine the independent effect of preoperative symptoms on survival after surgical correction of aortic regurgitation (AR).

BACKGROUND

Aortic valve replacement for severe AR is recommended after New York Heart Association functional class III or IV symptoms develop. However, whether severe preoperative symptoms have a negative influence on postoperative survival remains controversial.

METHODS

Preoperative characteristics and postoperative survival in 161 patients with functional class I or II symptoms (group 1) were compared with those in 128 patients with class III or IV symptoms (group 2) undergoing surgical repair of severe isolated AR between 1980 and 1989.

RESULTS

Compared with group 1, group 2 patients were older (p < 0.0001), were more often female (p = 0.001) and more often had a history of hypertension (p = 0.001), diabetes mellitus (p = 0.029) or myocardial infarction (p = 0.005) and were more likely to require coronary artery bypass graft surgery (p < 0.0001). The operative mortality rate was higher in group 2 (7.8%) than in group 1 (1.2%, p = 0.005), and the 10-year postoperative survival rate was worse (45% +/- 5% [group 2] vs. 78% +/- 4% [group 1], p < 0.0001). Compared with age- and gender-matched control subjects, long-term postoperative survival was similar to that expected in group 1 (p = 0.14) but significantly worse in group 2 (p < 0.0001). On multivariate analysis, functional class III or IV symptoms were significant independent predictors of operative mortality (adjusted odds ratio 5.5, p = 0.036) and worse long-term postoperative survival (adjusted hazard ratio 1.81, p = 0.0091).

CONCLUSIONS

In the setting of severe AR, preoperative functional class III or IV symptoms are independent risk factors for excess immediate and long-term postoperative mortality. The presence of class II symptoms should be a strong incentive to consider immediate surgical correction of severe AR.

Surgery for aortic regurgitation in women. Contrasting indications and outcomes compared with men

BACKGROUND

Indications for surgical correction of aortic regurgitation have been established mostly in men and have not been validated in women. The outcome of this surgical correction in women is unknown.

METHODS AND RESULTS

Baseline characteristics and postoperative outcomes were compared between 51 women and 198 men undergoing surgery for isolated aortic regurgitation between 1980 and 1989. Compared with men, women had surgery rarely for severe left ventricular enlargement (systolic diameter > or = 55 mm in 11% versus 27%, P = .031; diastolic diameter > or = 80 mm in 0% versus 16%, P < .0001) and more often for class III to IV symptoms (59% versus 32%, P < .0001). Operative mortalities were similar in women and men (3.9% and 4.5%, respectively). Among operative survivors, 10-year survival was worse for women than for men (39 +/- 9% versus 72 +/- 4%, P = .0002) and, in contrast with men, was worse than expected for women (P < .0001). Independent predictors of late survival were different for men (age and ejection fraction) and women (age and concomitant coronary bypass grafting). By multivariate analysis, female sex was an independent predictor of worse late survival (adjusted relative risk, 1.80; 95% CI, 1.04 to 3.11).

CONCLUSIONS

The generalization to women of the unadjusted left ventricular diameter surgical criteria established in men results in irrelevant criteria almost never reached in women, who often undergo surgery after developing severe symptoms. After surgery, women exhibit an excess late mortality, suggesting that surgical correction of aortic regurgitation should be considered at an earlier stage in women.

Aortic regurgitation complicated by extreme left ventricular dilation: long-term outcome after surgical correction

OBJECTIVES

This study sought to determine the outcome of aortic valve replacement for aortic regurgitation complicated by extreme left ventricular dilation.

BACKGROUND

Aortic valve replacement has been recommended in aortic regurgitation with extreme left ventricular dilation (diastolic dimension >/= 80 mm), but extreme left ventricular dilation raises concern about irreversible left ventricular dysfunction.

METHODS

Thirty-one patients with a preoperative echocardiographic diastolic dimension >/= 80 mm (group 1) undergoing operation for severe isolated aortic regurgitation between 1980 and 1989 were compared with 188 patients with a diastolic dimension <80 mm operated on during the same period (group 2).

RESULTS

Preoperatively, extreme left ventricular dilation was seen only in male patients and was associated with a reduced ejection fraction (43 +/- 12% vs. 53 +/- 11% [mean +/- SD], p < 0.0001). The postoperative outcome of group 1 was compared with that of male patients in group 2 (group 2M, n = 144). The operative mortality rates for groups 1 and 2M were 0% and 5.6%, respectively (p = 0.35). Late survival in operative survivors was similar in groups 1 and 2M, but compared with expected survival, an excess mortality was observed for group 1 (p = 0.024). Preoperative ejection fraction, but not diastolic dimension, independently predicted late survival and postoperative ejection fraction. Postoperatively, groups 1 and 2M showed a similar improvement in ejection fraction, but persistent left ventricular enlargement was more frequent in group 1.

CONCLUSIONS

Extreme left ventricular dilation due to aortic regurgitation is observed in male patients and is frequently associated preoperatively with a reduced ejection fraction but is not a marker of irreversible left ventricular dysfunction. Operative risk and late postoperative survival are acceptable in these patients, although a late excess mortality, predicted best by preoperative ejection fraction, is observed. Therefore, extreme left ventricular dilation is not a contraindication to operation, which should be performed before left ventricular dysfunction occurs.

Vasodilator therapy in chronic asymptomatic aortic regurgitation: enalapril versus hydralazine therapy

OBJECTIVES

This study attempted to evaluate the long-term efficacy of enalapril versus hydralazine therapy on left ventricular volume, mass and function as well as on the renin-angiotensin system in chronic asymptomatic aortic regurgitation.

BACKGROUND

We tested the hypothesis that early administration of a vasodilator drug might be able to reduce left ventricular dilation and mass expansion. Because the renin-angiotensin system may be activated in chronic aortic regurgitation, early enalapril therapy might be beneficial.

METHODS

Between 1990 and 1993, 76 asymptomatic nonrheumatic patients with mild to severe chronic aortic regurgitation were enrolled in a randomized, double-blind trial comparing enalapril with hydralazine. All patients underwent serial noninvasive studies. Seventy patients completed the 12-month follow-up.

RESULTS

At 1 year, patients receiving enalapril had a significant reduction in left ventricular end-diastolic and end-systolic volume indexes (124 +/- 15 vs. 108 +/- 17 ml/m2, p < 0.01; 50 +/- 12 vs. 40 +/- 14 ml/m2, p < 0.01, respectively) and mass index (131 +/- 16 vs. 113 +/- 19 g/m2, p < 0.01), whereas hydralazine therapy showed no significant changes. Both regimens not only had a significant reduction in left ventricular mean wall stress but also had a mild increase in exercise duration. Only enalapril therapy achieved a significant inhibition of the renin-angiotensin system, in contrast to hydralazine therapy. Moreover, the multiple r2 value from the analysis for end-diastolic volume index using the two variables of age and treatment drugs was 72.1% (p < 0.01).

CONCLUSIONS

Both regimens decrease left ventricular mean wall stress. Enalapril therapy achieves significant left ventricular mass regression, left ventricular end-diastolic and end-systolic volume index reduction and renin-angiotensin system suppression. These findings suggest that early unloading enalapril therapy has the potential to favorably influence the natural history of chronic aortic regurgitation.

Nifedipine in asymptomatic patients with severe aortic regurgitation and normal left ventricular function

BACKGROUND

Vasodilator therapy with nifedipine reduces left ventricular volume and mass and increases the ejection fraction in asymptomatic patients with severe aortic regurgitation.

METHODS

To assess whether vasodilator therapy reduces or delays the need for valve replacement, we randomly assigned 143 asymptomatic patients with isolated, severe aortic regurgitation and normal left ventricular systolic function to receive either nifedipine (20 mg twice daily, 69 patients) or digoxin (0.25 mg daily, 74 patients).

RESULTS

By actuarial analysis, we determined that after six years a mean (+/- SD) of 34 +/- 6 percent of the patients in the digoxin group had undergone valve replacement, as compared with only 15 +/- 3 percent of those in the nifedipine group (P < 0.001). In the digoxin group, valve replacement (in a total of 20 patients) was performed because of left ventricular dysfunction (ejection fraction < 50 percent) in 75 percent, left ventricular dysfunction plus symptoms in 10 percent, and symptoms alone in 15 percent. In the nifedipine group, all six patients who underwent valve replacement did so because of the development of left ventricular dysfunction. In addition, all the patients in both groups who underwent aortic-valve replacement had an increase of 15 percent or more in the left ventricular end-diastolic volume index. After aortic-valve replacement, 12 of the 16 patients (75 percent) in the digoxin group and all six patients in the nifedipine group who had had an abnormal left ventricular ejection fraction before surgery had a normal ejection fraction.

CONCLUSIONS

Long-term vasodilator therapy with nifedipine reduces or delays the need for aortic-valve replacement in asymptomatic patients with severe aortic regurgitation and normal left ventricular systolic function.

A new modification of debridement valvuloplasty for acquired aortic valve disease

A high speed electric rasp was used to remove fibrous thickening from the aortic valve in conjunction with aortic valve commissurotomy in ten patients. All patients had moderate rheumatic aortic valve disease combined with severe mitral valve disease, and were treated by mitral valve replacement and aortic valve repair. All patients survived the operative procedure. There were no deaths or complications during hospitalization related to the valve repair process. The transaortic valve gradient was relieved from an average of 21.0 +/- 8.6 mmHg to 5.6 +/- 4.0 mmHg (catheterization), and from moderate to less-than-mild stenosis (echocardiography). Aortic valve regurgitation was reduced from an average of 2.2+ to 0.7+ on a scale of 0 to 4+ (aortography), and from an average of 2.5+ to 1.1+ on a scale of 0 to 4+ (echocardiography). During the follow-up period, no patients were reoperated on because of aortic valve dysfunction. Follow-up echocardiographic study demonstrated that the transaortic pressure gradient and valvular regurgitation had not progressed, and immediate postoperative conditions were maintained. There were two late deaths not related to the aortic valve. One patient died of prosthetic valve endocarditis in the mitral prosthesis 14 months postoperatively, and the other of a cerebrovascular accident 21 months postoperatively. Based on these data, we believe that aortic valve repair with a high speed electric rasp can effectively relieve aortic stenosis, reduce valvular regurgitation, and provide an excellent hemodynamic result at early and mid-term follow-up.

Combined conventional mechanical and ultrasonic debridement for aortic valvular stenosis

Ultrasound decalcification of aortic valve stenosis was performed in 31 patients. There were 16 men and 15 women with a mean age of 71.03 +/- 9.6 years (range, 51 to 89 years). Each had severe calcific aortic stenosis with an aortic valve gradient greater than 40 mm Hg, aortic valve area (AVA) less than 0.6 cm2, and no serious insufficiency. Feasibility of aortic valve debridement was determined under direct vision. Intraoperative epicardial or transesophageal color Doppler two-dimensional echocardiography was used before and after the aortic valve debridement to evaluate aortic cusp motion and aortic regurgitation. Direct transseptal aortic valve gradient was measured on all patients before and after aortic valve debridement, and the AVA was determined. Aortic valve debridement was performed as the primary procedure in 17 cases and combined with other cardiac procedures in 14 patients. Preoperative aortic valve gradient was reduced from 72.5 +/- 22.5 mm Hg (range, 40 to 130 mm Hg) to 15.5 +/- 11.9 mm Hg (range, 2 to 50 mm Hg), and the average AVA of 0.41 +/- 0.10 cm2 (range, 0.22 to 0.63 cm2) was increased to 1.55 +/- 0.58 cm2 (range, 0.65 to 3.50 cm2) after ultrasound decalcification. There were two early deaths in octogenerian, high-risk patients, and two late deaths (6.45% early and 6.45% late mortality), none of them related to AVD. Postoperative follow-up included clinical evaluation and color Doppler echocardiography every 6 months. The aortic valve gradient was measured using a continuous-wave Doppler probe, and the AVA was calculated by the simplified continuity equation: AVA = aAOA x vLVOT/vAV.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms for left ventricular systolic dysfunction in aortic regurgitation: importance for predicting the functional response to aortic valve replacement

To test the hypothesis that the combined use of the time-varying elastance concept and conventional circumferential stress-shortening relations would elucidate differential mechanisms for left ventricular systolic dysfunction in severe, chronic aortic regurgitation and therefore predict the functional responses to aortic valve replacement, 31 control patients and 37 patients with aortic regurgitation were studied. The studies included micromanometer left ventricular pressure determinations, biplane contrast cineangiograms under control conditions and radionuclide angiograms under control conditions and during methoxamine or nitroprusside infusions with right atrial pacing. The patients with aortic regurgitation were classified into three groups: Group I had normal Emax and stress-shortening relations, Group II had abnormal Emax but normal stress-shortening relations and Group III had abnormal Emax and stress-shortening relations. The left ventricular end-diastolic and end-systolic volumes showed a progressive increase and the ejection fraction showed a progressive decrease from Group I to III; these values differed from those in the control patients (p less than 0.001). In Group I, there was a decrease in left ventricular volumes (p less than 0.05) but no significant change in ejection fraction (61 +/- 7% versus 63 +/- 4%) after aortic valve replacement. In contrast, in Group II, reduction in left ventricular volumes (p less than 0.01) was associated with an increase in ejection fraction from 50 +/- 8% to 64 +/- 11% (p less than 0.01). Finally, in Group III, reduction in left ventricular volumes (p less than 0.05) was associated with a further decrement in ejection fraction from 35 +/- 13% to 30 +/- 13%. Group I patients had compensated adequately for chronic volume overload. However, Group II had left ventricular dysfunction that was associated with an increase in the left ventricular volume/mass ratio compared with that in the control patients and Group I (p less than 0.05 for both), suggesting inadequate hypertrophy and assumption of spherical geometry. Finally, irreversible myocardial dysfunction had supervened in Group III. In conclusion, a combined analysis of left ventricular chamber performance using the time-varying elastance concept and myocardial performance using conventional circumferential stress-shortening relations provides complementary information that elucidates differential mechanisms for left ventricular systolic dysfunction and therefore predicts the functional response to aortic valve replacement.

Long-term nifedipine unloading therapy in asymptomatic patients with chronic severe aortic regurgitation

Vasodilating agents acutely reduce regurgitant volume and improve left ventricular performance in aortic regurgitation, but more information is necessary about their long-term efficacy. To evaluate the effects of 12 months of therapy with nifedipine, a randomized, double-blind, placebo-controlled trial was performed in 72 asymptomatic patients with severe aortic regurgitation. At 12 months, patients receiving nifedipine had a significant reduction in left ventricular end-diastolic volume index (110 +/- 19 versus 136 +/- 22 ml/m2, p less than 0.01) and mass (115 +/- 19 versus 142 +/- 16 g/m2, p less than 0.01) measured by two-dimensional echocardiography. They also had a reduction in left ventricular mean wall stress (360 +/- 27 versus 479 +/- 36 kdyne/cm2, p less than 0.001) and an increase in ejection fraction (72 +/- 8% versus 60 +/- 6%, p less than 0.05). These data show that the long-term unloading action of nifedipine is able to reverse left ventricular dilation and hypertrophy and suggest that such therapy has the potential to delay the need for valve replacement in asymptomatic patients.

Aortic valve repair for aortic stenosis in adults

The stenotic aortic valve was surgically repaired in 48 adults, 21 women and 27 men, aged 38 to 83 years. Five had congenital aortic stenosis (AS), with a mean aortic valve gradient and area of 58 +/- 23 mm Hg (standard deviation) and 0.54 +/- 0.13 cm2, respectively; 32 had senile AS with a mean aortic valve gradient and area of 43 +/- 20 mm Hg and 0.98 +/- 0.41 cm2; and 11 had rheumatic AS with a mean aortic valve gradient and area of 59 +/- 24 mm Hg and 0.47 +/- 0.15 cm2. Only 6 patients underwent isolated aortic valvoplasty, 11 underwent concomitant mitral valve procedure, and 34 underwent concomitant coronary revascularization. Repair consisted of decalcification in 33 patients and decalcification as well as commissurotomy in 15 patients. There were three hospital deaths, none related to the aortic valve. Only 2 patients (both rheumatic) did not improve clinically. During follow-up (mean, 64 +/- 41 months) aortic valve restenosis developed in 24% (10 patients, 3/5 congenital, 4/11 rheumatic, and 3/32 senile) at a mean of 64 +/- 28 months. Postoperative Doppler echocardiographic assessment of 21 patients with senile AS at 1.1 +/- 2.7 and 18.1 +/- 1.4 months showed significantly lower aortic valve gradient and improved area in comparison with preoperative values. At 36 +/- 2.7 months, aortic valve gradient and area were not significantly different than preoperative values, and at 58.5 +/- 2.6 months aortic valve gradient was 1.41 (p = 0.07) times the preoperative value. At 7 years, actuarial freedom from aortic valve-related symptoms of the patients with senile AS was 87%. We conclude that in select patients aortic valve repair results in excellent relief of AS. Late restenosis is expected and more likely to occur in the valves with congenital and rheumatic disease than in those with senile disease.

Effect of digoxin and vasodilators on left ventricular function in aortic regurgitation

In order to assess the relative value of digoxin, nifedipine and hydralazine on left ventricular performance at rest and during exercise, we studied 10 men with moderately severe chronic aortic regurgitation using two-dimensional echocardiography. Digoxin after one month at therapeutic serum levels increased resting ejection fraction as compared to control [0.54 +/- 0.08 (SD) vs 0.47 +/- 0.08, respectively, P less than 0.03]. Ejection fraction decreased during exercise but the difference between digoxin and control was maintained. Stroke volume also was higher on digoxin than control at rest (93 +/- 15 vs 83 +/- 17 ml, P less than 0.02) and the larger stroke volume on digoxin was maintained during exercise. By contrast, stroke volume was reduced by one month of therapy with maximally tolerated nifedipine doses compared to control (74 +/- 8 vs 83 +/- 17 ml, P = 0.03) and this difference was maintained during exercise. Hydralazine in doses up to 225 mg/day for one month produced no significant changes in left ventricular performance compared to control at rest or during exercise. However, compared to digoxin ejection fraction at peak exercise was significantly less on hydralazine (0.39 +/- 0.9 vs 0.52 +/- 10, P less than 0.02). These data suggest that digoxin improved left ventricular performance and may be of benefit in the treatment of patients with chronic aortic regurgitation.

Chronic severe aortic regurgitation: a prospective follow-up of 60 asymptomatic patients

Sixty asymptomatic patients (age 26 +/- 10 years) with chronic severe aortic regurgitation were followed prospectively for 2.4 +/- 1.4 years. Based on previous echocardiographic end-systolic dimension (ESD) and angiographic ejection fraction (EF) correlations, the cohort was divided into group A (21 patients) with ESD greater than or equal to 48 mm and group B (39 patients) with ESD less than 48 mm. Group B had a faster ESD progression (NS) and 19 crossed over to group A. Thirteen patients, all with ESD greater than 48 mm, reached designated end points. One died of cerebral embolism and 12 (age 31.4 +/- 10.6 years) required aortic valve replacement (AVR). Of these, 9 of 12 were asymptomatic and 11 of 12 had significant left ventricular dysfunction (LVD). The preoperative ESD of 51.9 +/- 4.1 mm fell to 38.4 +/- 3.6 mm (p less than 0.001) postoperatively and the EF of 43.7 +/- 4.16 increased to 64.9 +/- 5.9 (p less than 0.001). We found (1) the progression was faster than in other series; (2) ESD greater than 48 mm was associated with significant progression; and (3) patients with EF above 40% showed no residual LVD after AVR.

Value of the treadmill exercise test in asymptomatic and minimally symptomatic patients with chronic severe aortic regurgitation

The value of the graded treadmill exercise test was assessed in 19 asymptomatic and minimally symptomatic (13 NYHA class I and 6 NYHA class II) male patients with chronic severe aortic regurgitation. It was observed that, in 2 patients who showed significant ST segment depression at peak exercise, the total exercise duration was significantly shorter (P less than 0.001) than in the patients not showing such changes. During left ventricular and aortic root angiography (in both patients) and selective left coronary angiography (in one of them), ST segment changes similar to those seen during exercise testing were observed. The mean rise in left ventricular end-diastolic pressure after injection of contrast material was significantly more (P less than 0.001) in these 2 patients compared to the other 17 patients. Both patients had normal resting M-mode echocardiographic parameters. It is concluded that ST segment depression on exercise testing and reduced exercise capacity are indicants of exercise-induced left ventricular dysfunction in asymptomatic and minimally symptomatic patients with chronic severe aortic regurgitation. Furthermore, it is suggested that this simple and cheap test can be used for serial evaluation of such patients in the absence of the facility of radionuclide cineangiography.

Intertest variability of echocardiographic and chest X-ray measurements: implications for decision making in patients with aortic regurgitation

Echocardiograms and chest X-ray examinations are commonly employed for serial measurements of left ventricular size and function in patients with chronic aortic insufficiency and often support or even determine therapeutic decisions. This study was undertaken to assess the intertest variability of these measurements made from M-mode echocardiograms and X-ray films performed 3 months apart without intervening clinical or therapeutic changes in 22 patients with significant but asymptomatic aortic insufficiency. End-diastolic and end-systolic dimensions, fractional shortening and cardiothoracic ratios were measured by the same reader, with the initial and 3 month tests being read both independently and together for comparison. The mean values for the initial and 3 month studies were similar, but the intertest variability was substantial, especially when the two tests were read independently. The 95% prediction limits are approximately 50% smaller when the serial studies are read together for comparison. The coefficient of variation for end-diastolic and end-systolic dimensions was 6.1 and 10.1%, respectively, and that for fractional shortening was 17.1%. These findings translate into 95% level prediction limits exceeding +/- 8 mm for left ventricular dimensions and 0.12 for fractional shortening; changes on serial evaluations would have to exceed these values to be considered with a high degree of certainty to represent more than random variability. Although this variability may reflect a number of biologic and technical factors, it emphasizes the need to be cautious in making decisions based solely on changes between two tests, particularly if they are not evaluated together.

Progression of myocardial dysfunction in asymptomatic patients with severe aortic insufficiency

By serial echocardiographic examinations, we investigated the parameters predictive of left ventricular (LV) deterioration in 38 asymptomatic patients with severe aortic insufficiency (AI). Based on their first echocardiograms, patients were divided into two groups: Group 1 (n = 30) had normal fractional shortening (FS); Group 2 (n = 8) had abnormal FS. Similar values of LV end-diastolic, end-systolic dimension (EDD, ESD), FS, radius/thickness ratio, and mean wall stress characterized stable and unstable patients of Group 1; unstable patients, who developed abnormal values of FS during the follow-up, showed significantly lower values of the contractility index (peak arterial pressure/end-systolic volume ratio, PAP/ESV). The unstable patients, moreover, were distributed near the onset of the downslope and moved along the descending limb of the curvilinear pump performance-myocardial contractility relation. No changes occurred in Group 2 patients during follow-up. Three unstable Group 1 patients and the 8 patients of Group 2 underwent aortic valve replacement (AVR): postoperative EDD was less than 65 mm and the changes from before to after AVR were greater than 11 mm in all cases. We conclude that the pump performance-myocardial contractility relation visualized the unstability of LV function in asymptomatic patients and that AVR can be delayed after the appearance of an abnormal FS for at least 36 months.

Cardiovascular response to dynamic exercise in patients with chronic symptomatic mild-to-moderate and severe aortic regurgitation

Fifteen patients with symptomatic mild-to-moderate and severe chronic aortic regurgitation (AR) performed supine bicycle exercise while measurements of rest and exercise hemodynamics and left ventricular function were obtained. A continuous Doppler method was used to determine the change in distribution of total left ventricular stroke volume between forward stroke volume and regurgitant volume (RgV) with exercise. The pulmonary arterial wedge pressure (PAWP) was lower in the mild-to-moderate AR group than in the severe AR group at rest (8 +/- 1.2 vs 19 +/- 3.6 mm Hg, p = 0.01) and during exercise (15 +/- 3.9 vs 30 +/- 4.3 mm Hg, p = .02). In all patients there were increases in heart rate (78 +/- 4 to 96 +/- 5 beats/min, p less than .001), forward stroke volume (41 +/- 2 to 46 +/- 2 ml/m2), and the cardiac index (3.1 +/- 0.2 to 4.4 +/- 0.3 liters/min-m2, p less than .001), despite a fall in total left ventricular stroke volume index from 84 +/- 5 to 76 +/- 5 ml/m2 (p = .03). The systemic vascular resistance (SVR) decreased with exercise from 1277 +/- 72 to 1031 +/- 64 dynes-sec/cm5 (p less than .001), and the RgV and regurgitant fraction (RgF) both decreased with exercise from 43 +/- 5 ml/m2 to 30 +/- 4 ml/m2 (p = .002) and 0.50 +/- 0.03 to 0.37 +/- 0.03 (p less than .001), respectively. Left ventricular ejection fraction increased on exercise from 0.51 +/- 0.03 to 0.55 +/- 0.03 (p = .02) for the group, but it either decreased or failed to increase by at least 0.05 in seven of 13 patients. The change in ejection fraction on exercise was directly related to the change in SVR (r = .80, p less than .001). We conclude that: in patients with mild-to-moderate AR, the PAWP is generally normal at rest and exercise, in most of those with severe AR, the PAWP is elevated at rest and increases significantly with exercise, which is the likely mechanism for dyspnea on exertion in these patients, the cardiac index in both groups is normal at rest and increases on exercise, the increase in cardiac output results from both an increased heart rate and forward stroke volume, the increase in forward stroke volume results from reductions of RgV and RgF, the RgV and RgF are decreased due to a decreased SVR, and the ejection fraction response to exercise is variable and correlates best with changes in SVR with exercise.

Survival and functional results after valve replacement for aortic regurgitation from 1976 to 1983: impact of preoperative left ventricular function

Recent studies suggest that preoperative left ventricular function may no longer be an important determinant of survival or functional results after operation for aortic regurgitation because of improved operative techniques. To assess the effect of left ventricular function on prognosis in the current surgical era, we performed echocardiographic and radionuclide angiographic studies in 80 consecutive patients undergoing valve replacement from 1976 to 1983. No patient had associated coronary artery disease. For all patients, 5 year survival was 83 +/- 5%, significantly better than the 62 +/- 9% 5 year survival in our patients operated on from 1972 to 1976. Preoperative resting left ventricular ejection fraction (p less than .001), fractional shortening (p less than .001), and end-systolic dimension (p less than .01) were the most significant predictors of survival (univariate life-table analysis). Five year survival was 63 +/- 12% in patients with subnormal ejection fraction (n = 50) compared with 96 +/- 3% in those with normal ejection fraction (n = 30). Patients with subnormal left ventricular ejection fraction and poor exercise tolerance or prolonged duration of left ventricular dysfunction (greater than 18 months) comprised the high-risk subgroup (5 year survival 52 +/- 11%). Patients in this subgroup also had persistent left ventricular dysfunction after operation, with greater left ventricular end-diastolic dimensions and reduced ejection fraction (both p less than .001) compared with patients with normal preoperative left ventricular ejection fraction or a brief duration of left ventricular dysfunction (less than 14 months). Cold hyperkalemic cardioplegia was used for myocardial preservation in 46 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between functional class and cardiac performance in patients with chronic aortic insufficiency

We have evaluated the relationship of New York Heart Association functional class (FC) assessment to rest and exercise hemodynamics and resting left ventricular (LV) functional data in 75 consecutive patients with isolated, chronic aortic insufficiency. Although there was a tendency for hemodynamic and angiographic variables to worsen as FC increased there was considerable overlap between patients assigned to the various groups. Statistically significant differences were seen only for resting left ventricular end-diastolic pressure (LVEDP) and pulmonary artery wedge (PAW) pressure which were higher in FC 3/4 patients than in FC 1 or 2 patients. The results of our study suggest that FC assignment cannot be used to accurately define underlying LV performance or hemodynamics in an individual patient with chronic aortic insufficiency. However, since severe abnormalities are unlikely to be present in asymptomatic patients, routine detailed frequent investigation does not seem warranted in this group. As FC worsens, the likelihood of left ventricular dysfunction increases. Thus, the presence of symptoms is an indication for more extensive evaluation.

Chronic aortic regurgitation: reassessment of the prognostic value of preoperative left ventricular end-systolic dimension and fractional shortening

The prognostic significance of a preoperative echocardiographic left ventricular end-systolic dimension (ESD) greater than 55 mm and/or fractional shortening (FS) of 25% or less was evaluated retrospectively in 84 patients who had undergone aortic valve replacement for isolated chronic aortic regurgitation due to various causes. Postoperative survival, improvement in symptoms, and echocardiographic evidence of regression of left ventricular dilatation and hypertrophy were compared between patients with a preoperative ESD greater than 55 mm (category 1) and those with an ESD of 55 mm or less (category 2) and between patients with FS of 25% or less (category 3) and those with FS greater than 25% (category 4). Patients in categories 1 and 3 had a higher preoperative left ventricular end-diastolic dimension (EDD) and cross-sectional area than those in categories 2 and 4, respectively, but their preoperative functional impairment (NYHA class) was similar. There were 13 deaths, only two of which (one early, one late) could be attributed to left ventricular dysfunction. In both, FS was 25% or less and in one ESD was greater than 55 mm. There was a weak association without useful positive predictive value between the echocardiographic variables and postoperative death due to all causes. Among 42 patients with a preoperative ESD greater than 55 mm and/or FS of 25% or less, 33 (79%) were alive at a mean follow-up of 29.5 months. Symptoms improved in all categories of survivors, with the postoperative NYHA class being similar between categories 1 and 2 and between categories 3 and 4. Among 48 survivors with high-quality echocardiograms both before and after surgery, EDD fell in all groups but fell to a lesser extent in category 3 than in category 4. Postoperative cross-sectional area fell to the same level in all categories. Follow-up intervals were similar in all categories. We conclude that in patients undergoing aortic valve replacement for chronic aortic regurgitation, a preoperative ESD greater than 55 mm or an FS of 25% or less does not reliably predict early or late death, does not correlate with lack of improvement in symptoms, and does not preclude postoperative regression of left ventricular dilatation and hypertrophy. Thus these echocardiographic criteria alone cannot be used for the timing of surgical intervention in these patients.

Afterload mismatch in aortic and mitral valve disease: implications for surgical therapy

In the management of patients with valvular heart disease, an understanding of the effects of altered loading conditions on the left ventricle is important in reaching a proper decision concerning the timing of corrective operation. In acquired valvular aortic stenosis, concentric hypertrophy generally maintains left ventricular chamber size and ejection fraction within normal limits, but in late stage disease function can deteriorate as preload reserve is lost and aortic stenosis progresses. In this setting, even when the ejection fraction is markedly reduced (less than 25%), it can improve to normal after aortic valve replacement, suggesting that afterload mismatch rather than irreversibly depressed myocardial contractility was responsible for left ventricular failure. Therefore, patients with severe aortic stenosis and symptoms should not be denied operation because of impaired cardiac function. In chronic severe aortic and mitral regurgitation, operation is generally recommended when symptoms are present, but whether to recommend operation to prevent irreversible myocardial damage in patients with few or no symptoms has remained controversial. In aortic regurgitation, left ventricular function generally improves postoperatively, even if it is moderately impaired preoperatively, indicating correction of afterload mismatch. Most such patients can be carefully followed by echocardiography. However, in some patients, severe left ventricular dysfunction fails to improve postoperatively. Therefore, when echocardiographic studies in the patient with severe aortic regurgitation show an ejection fraction of less than 40% (fractional shortening less than 25%) plus enlarging left ventricular end-diastolic diameter (approaching 38 mm/m2 body surface area) and end-systolic diameter (approaching 50 mm or 26 mm/m2), confirmation of these findings by cardiac catheterization and consideration of operation are advisable even in patients with minimal symptoms. In chronic mitral regurgitation, maintenance of a normal ejection fraction can mask depressed myocardial contractility. Pre- and postoperative studies in such patients have shown a poor clinical result after mitral valve replacement, associated with a sharp decrease in the ejection fraction after operation. This response appears to reflect unmasking of decreased myocardial contractility by mitral valve replacement, with ejection of the total stroke volume into the high impedance of the aorta (afterload mismatch produced by operation).(ABSTRACT TRUNCATED AT 400 WORDS)

Postoperative regression of left ventricular dimensions in aortic insufficiency: a long-term echocardiographic study

The ability of preoperative M-mode echocardiography to predict the clinical course and the decrease in left ventricular size was assessed in 42 patients after uncomplicated valve replacement for isolated aortic insufficiency. During follow-up study, one patient died of chronic heart failure. The New York Heart Association functional class of the 41 survivors improved from 2.4 to 1.2. All patients had a preoperative M-mode echocardiogram. Serial echocardiographic measurements, available in 33 patients, showed a sustained decrease in left ventricular end-diastolic dimension after the first postoperative year from 73 +/- 8 to 57 +/- 9 mm at 6 to 12 months and to 53 +/- 9 mm at 3 years postoperatively (p less than 0.01). Left ventricular cross-sectional area decreased from 31 +/- 8 to 26 +/- 7 cm2 and then to 23 +/- 5 cm2 at the latest follow-up study (p less than 0.01). At 3 years postoperatively, M-mode echocardiograms were available in 37 patients: 24 had a normal left ventricular dimension (group 1), while 13 still had an enlarged left ventricle (group 2). The clinical course in these two groups was similar. The best preoperative predictor of persistent left ventricular enlargement was the end-diastolic dimension (p less than 0.05), whereas fractional shortening and the end-diastolic radius/thickness ratio were not predictive.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic evaluation of the response to afterload stress test in young asymptomatic patients with chronic severe aortic regurgitation: sensitivity of the left ventricular end-systolic pressure-volume relationship

The detection of myocardial depression is an important goal in the management of patients with chronic severe aortic regurgitation but may be quite difficult at an early stage by the conventional basal measures of contractility. The response to afterload stress determined by angiotensin challenge and the end-systolic pressure-volume relationship was evaluated echocardiographically in 16 asymptomatic or mildly symptomatic patients with chronic severe aortic regurgitation, ages 15 to 56 years (mean 32 +/- 12). Nine normal subjects, ages 25 to 41 years (mean 31 +/- 5), served as a control group. In the group with aortic regurgitation, end-systolic dimensions were greater than 55 mm in five of 16 patients and fractional shortening was 25% or less in two of 16. In the control group angiotensin caused a decrease of stroke volume index in six out of nine patients (15% at the most) and a mild increase in three. In the group with aortic regurgitation stroke volume index decreased by 15% or more of the basal value in nine of 16 patients and increased or decreased by less than 15% in seven of 16. Ejection fraction decreased in both groups, from 61 +/- 6% to 52 +/- 7% in the control group and from 56 +/- 6% to 45 +/- 5% in the group with aortic regurgitation. Ventricular function curves were derived by relating end-diastolic volume index to stroke work index; seven of 16 patients had abnormal responses reflecting an afterload mismatch.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between myocardial contractility, hypertrophy and pump performance in patients with chronic aortic regurgitation: an echocardiographic study

The aim of this study was to establish prognostic indices and to detect irreversible left ventricular dysfunction before aortic valve replacement in patients with chronic aortic regurgitation. Therefore, we determined the left ventricular pump/contractility relation (expressed as a ration between ejection fraction and peak systolic pressure/end-systolic volume), afterload mismatch (the relation between the ejection fraction and mean systolic wall stress) and the left ventricular end-diastolic radius/posterior wall thickness ratio in 52 patients with chronic aortic regurgitation by means of M-mode echocardiography. These indices were also calculated in 14 patients with idiopathic dilated cardiomyopathy and in 20 normal controls. The indices allowed separation of normals and patients with mild to moderate aortic insufficiency from patients with idiopathic dilated cardiomyopathy indicating that these indices could distinguish between patients with a reversible afterload mismatch and those with irreversible impaired muscle function. The 38 patients with severe aortic insufficiency showed a large overlap between normal and abnormal indices. Twelve of these patients had a pump/contractility index and a ratio between ejection fraction and wall stress similar to that found in patients with idiopathic dilated cardiomyopathy. All these patients, however, had a left ventricular end-diastolic radius/thickness ratio greater than 4 indicating "inadequate hypertrophy". Of these, 3 patients died perioperatively and 4 developed congestive heart failure within 12 months postoperatively. We conclude that an end-diastolic radius/thickness ratio greater than 4 is a sensitive but not a specific preoperative indicator of irreversible left ventricular damage in patients with chronic aortic regurgitation. This index is readily obtained preoperatively by M-mode echocardiography.

Reversal of left ventricular dysfunction after aortic valve replacement for chronic aortic regurgitation: influence of duration of preoperative left ventricular dysfunction

Preoperative left ventricular systolic function is an important predictor of postoperative prognosis in patients with aortic regurgitation. Although left ventricular dysfunction is reversible after aortic valve replacement to a greater extent in patients with good preoperative exercise capacity compared with patients with impaired exercise capacity, not all patients with preserved exercise capacity demonstrate improved left ventricular function after aortic valve replacement. To determine the influence of duration of preoperative left ventricular dysfunction on postoperative reversal of left ventricular dysfunction, we studied 37 patients with aortic regurgitation who preoperatively had left ventricular dysfunction, defined as subnormal echocardiographic fractional shortening (less than 29%), and good preoperative exercise capacity, defined as completion of stage I of the NIH treadmill protocol without limiting symptoms. Eight patients were asymptomatic. In 11 patients left ventricular dysfunction was documented 18 to 57 months preoperatively (prolonged); in 10 patients left ventricular dysfunction developed in an interval of 14 months or less preoperatively (brief); in 16 patients duration of left ventricular dysfunction was unknown. Patients with brief vs those with prolonged left ventricular dysfunction did not differ with respect to severity of preoperative symptoms or exercise tolerance, echocardiographically determined left ventricular dimensions or fractional shortening (25 +/- 3% [SD] vs 25 +/- 3%), or radionuclide angiographic ejection fraction (42 +/- 5% vs 42 +/- 5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormal left ventricular response to isometric exercise in pure, isolated aortic regurgitation: beneficial effects of nifedipine

To examine the effects of nifedipine on the left ventricular (LV) functional response to isometric exercise in patients with aortic regurgitation (AR), 20 patients with isolated, moderate to severe AR performed 3 minutes of handgrip exercise at 33% of their maximal voluntary contraction, before and after administration of 20 mg of sublingual nifedipine. Although handgrip exercise produced similar increases in heart rate and systolic blood pressure before and after nifedipine treatment, heart rate was higher and systolic blood pressure lower with handgrip exercise during nifedipine treatment. LV end-diastolic volume index was not different during the control period and nifedipine handgrip exercise, but the increase in end-systolic volume index was smaller and the ejection fraction was higher during nifedipine handgrip exercise. Nifedipine reduces afterload and ameliorates handgrip exercise-induced LV dysfunction in patients with AR.

Aortic and mitral valve incompetence: long-term follow-up (10 to 19 years) of patients treated with the Starr-Edwards prosthesis

The long-term course (mean 15 years) of 336 patients with valvular incompetence who underwent Starr-Edwards ball valve implantation between 1962 and 1971 was reviewed. Eighteen patients (10%) with aortic valve replacement and 24 (16%) with mitral valve replacement died early postoperatively. Mortality remained high (31%) in the first 3 years after aortic valve replacement; it was highest (13%) in the first year after mitral valve replacement and then approached the normal rate. The most common mode of death was sudden death after aortic and cardiac failure after mitral valve replacement. At follow-up, 76% of survivors had improved symptomatically. Three instances of primary valve malfunction occurred. The probability of freedom from thromboembolism at 15 years postoperatively was 56% for aortic valve replacement and 52% for mitral valve replacement. The Starr-Edwards valve prosthesis is durable over prolonged follow-up period, but thromboembolism remains a persistent problem. Survival may be normal for patients surviving the early postoperative years.

Immediate and long-term results in aortic valve replacement

In a 12-year period, 127 patients with isolated aortic valve disease underwent valve replacement surgery. Long-term results are presented in regard to patients with operation between 1967 and 1974 and immediate results in the later cases. The main conclusions from the study are that the type of myocardial protection is important for the perioperative mortality rate. This rate was 18% in patients operated on in normothermia and 6% in those with chemical cardioplegia. No significant correlation was found between preoperative NYHA grouping and mortality or complication rate, and the long-term result was independent of the type of valvular prosthesis.

Surgical repair of annulo-aortic ectasia in children

Results of total repair of annulo-aortic ectasia in three children are presented. The operations were performed on vital indications. All the children survived. In one of them a total AV-block developed and required permanent pacemaker treatment. There were no late complications in the follow-up period of 22 to 41 months.

Valvular heart disease: a perspective

Valve replacement has been one of the most important advances in the management of patients with valvular heart disease. The 10 and 15 year survival rate after isolated aortic and mitral valve replacement with the Starr-Edwards valve is 56 and 44%, respectively. At 5 and 7 years, survival with the Björk-Shiley, porcine bioprosthesis and the Starr-Edwards valve is similar. Patients operated on during the last 5 to 10 years have a much better survival rate than those operated on in the 1960s; therefore, the 10 and 15 year survival of those operated on recently should improve. All patients with a mechanical prosthesis need long-term anticoagulant therapy with drugs of the coumadin type. Porcine bioprostheses have a low failure rate up to 5 years after valve replacement; after this, valve failure occurs at an increasing rate, but the incidence at 10 and 15 years is not known. Valve replacement usually produces a marked improvement in the symptomatic status of the patient because of improved hemodynamics; ventricular function is improved in selected subsets of patients. The role of long-term vasodilator therapy has not been fully determined. Antibiotic prophylaxis for secondary prevention of rheumatic carditis and for prevention of infective endocarditis is important.

Echocardiography in chronic aortic insufficiency. Is valve replacement too late when left ventricular end-systolic dimension reaches 55 mm?

To determine whether a ventricular (LV) end-systolic dimension (ESD) greater than or equal to 55 mm and LV left fractional shortening less than 25% are risk factors for aortic valve replacement (AVR) in patients with aortic insufficiency, we analyzed the clinical course and M-mode echocardiograms in 47 consecutive patients who underwent AVR for isolated symptomatic AI. Group 1 patients (n = 27) had a preoperative ESD less than 55 mm (mean 44 mm, range 30-52 mm) and group 2 patients (n = 20) had a preoperative ESD greater than or equal to 55 mm (mean 62 mm, range 55-85 mm). One patient in group 1 and 10 patients in group 2 had left ventricular fractional shortening less than 25%. There were no perioperative or postoperative deaths during an average follow-up of 41 months (range 6-76 months). Five patients had perioperative myocardial infarctions (MIs), three in group 1 and two in group 2. Since myocardial protection with cold potassium cardioplegia was instituted, no patient has suffered a perioperative MI. The average preoperative New York Heart Association functional classification was 2.3 (group 1) and 2.6 (group 2). Postoperatively, it was 1.2 in group 1 and 1.1 in group 2. Thirty-three patients (20 in group 1 and 13 in group 2) had echocardiograms at least 1 year after AVR. Of these, LV-end diastolic dimension decreased fro 67 +/- 6 to 53 +/- 6 mm (mean +/- SD) in group 1 (p less than 0.001) and from 79 +/- 3 to 55 +/- 6 mm in group 2 (p less than 0.001). The LVESD also decreased, but this is difficult to interpret because of frequent postoperative abnormal interventricular septal motion. The LV cross-sectional area, an index of LV mass, decreased in group 1 from 25 +/- 5 to 20 +/- 5 cm2 (p lss than 0.001) and in group 2 from 32 +/- 9 to 20 +/- 5 cm2 (p less than 0.001). Postoperative end-diastolic dimension and cross-sectional area were not significantly different between the two groups. We concluded that in aortic insufficiency, a preoperative ESD greater than or equal to 55 mm does not preclude successful AVR, as judged by long-term survival, symptomatic relief, and normalization of LV dimensions assessed by echocardiography.

The effect of aortic valve replacement on survival

We retrospectively studied 252 operated and 47 unoperated patients with isolated aortic valve disease. Aortic valve replacement (AVR) was recommended to all patients based on clinical and hemodynamic data. Preoperative hemodynamic and angiographic data were similar in operated and unoperated cohorts. Seventy-one percent of patients received a Björk-Shiley prosthesis. Operative mortality was 7% for the entire surgical series. For patients with predominant aortic stenosis (AS), survival at 3 years was 87% in operated and 21% in unoperated patients (p less than 0.001). For patients with predominant aortic insufficiency (AI), the 5-year survival rate was 86% in operated and 87% in unoperated patients (NS). AVR improved long-term survival in patients with AS who had normal or impaired left ventricular (LV) function. In patients with AI and normal LV function, survival was not improved after AVR, but those with LV dysfunction who were operated on tended to survive longer (NS). Long-term survival of unoperated patients with AI was better than that in unoperated patients with AS. We conclude that AVR improves long-term survival in patients with AS who were normal or abnormal LV function, and that AVR does not change long-term survival in patients with AI, although those with LV dysfunction tended to survive longer.

Timing of operation for chronic aortic regurgitation

Left ventricular systolic function is an important determinant of long-term prognosis in patients with chronic aortic regurgitation. Data from several centers, using invasive and noninvasive assessment of left ventricular function, indicate that long-term postoperative survival is excellent, even in symptomatic patients, if preoperative left ventricular systolic function is normal. The long-term postoperative results are significantly worse in symptomatic patients with preoperative left ventricular systolic dysfunction, many of whom appear to have irreversible left ventricular failure before the onset of symptoms and are at a risk of late postoperative death from congestive heart failure. However, within this high risk subgroup long-term prognosis is excellent for patients, despite left ventricular dysfunction, if preoperative exercise capacity is preserved. In these patients, left ventricular dysfunction is likely to be reversible after operation. Hence, all patients with left ventricular dysfunction at rest should undergo aortic valve replacement, even if severe symptoms and deterioration in exercise tolerance have not developed. Once exercise tolerance becomes limited in such patients, the likelihood of irreversible left ventricular dysfunction is increased, and long-term postoperative survival is threatened.

Noninvasive assessment of myocardial contractility in asymptomatic patients with sever aortic regurgitation and normal left ventricular ejection fraction at rest

In 14 asymptomatic patients with isolated aortic insufficiency the slope k of the end-systolic pressure-volume relation was determined noninvasively with equilibrium radionuclide angiography. The results were compared with changes in left ventricular ejection fraction during maximal physical stress. Nine normal volunteers served as a control group. Patients with aortic insufficiency did not differ significantly from the control group with respect to left ventricular ejection fraction at rest (aortic insufficiency 62 + 8 percent, control 65 +/- 6; probability [p] = not significant [NS]), physical work capacity (aortic insufficiency 113 +/- 32 watts, control 117 +/- 25; p = NS) or age (aortic insufficiency 40 +/- 10 years, control 47 +/- 7; p = NS). The slope (k) of the end-systolic pressure-volume relation was found to be significantly lower in the group with aortic insufficiency (3.1 +/- 1.1) than in the control group (4.1 +/- 0.5; p less than 0.05). Patients with aortic insufficiency could be classified into two subgroups with respect to the slope k. In subgroup A (n = 7) the slope fell within the normal range (4.0 +/- 0.6) as defined by the control group, and the left ventricular exercise reserve was normal (6 percent +/- 1). In subgroup B (n = 7) the slope was significantly lower (2.2 +/- 0.6, p less than 0.01), indicating depressed myocardial contractility, and all patients experienced left ventricular dysfunction during exercise (left ventricular exercise reserve -5 +/- 5 percent). Thus, noninvasive determination of the end-systolic pressure-volume relation identified two subsets of asymptomatic patients with aortic insufficiency, one with impaired myocardial contractility and normal left ventricular exercise reserve and a second group with depressed myocardial contractility and left ventricular dysfunction during exercise. Therefore, an abnormal baseline contractile state in asymptomatic patients with aortic insufficiency may be uncovered by noninvasive determination of the end-systolic pressure-volume relation or by assessing the left ventricular exercise reserve. Serial studies in a larger group of patients undergoing surgical correction of the valve lesion are indicated to determine whether this information will be helpful in evaluating when to operate on asymptomatic patients with aortic insufficiency.

Preoperative criteria predictive of late survival following valve replacement for severe aortic regurgitation

Forty-five patients underwent aortic valve replacement (AVR) for severe isolated aortic regurgitation from 1973 to 1979. There were two (4.4%) hospital deaths, both functional class IV. Six patients with mechanical prosthesis not receiving anticoagulants were excluded from further analysis. These data relate to 39 patients; the two operative deaths, 35 patients with mechanical prosthesis receiving anticoagulants, and two with bioprosthesis. There were three late cardiac deaths with 5-year survival 85%; average annual mortality rate of 3%. The 5-year survival with pre-AVR left ventricular (LV) ejection fraction greater than or equal to 0.45 was 87% vs 54% less than 0.45, (p less than 0.04); cardiac index greater than or equal to 2.5 L/min/m2 92% vs 66% less than 2.5 (p less than 0.04); mean VCF greater than or equal to 0.75 vs less than 0.75 circ/sec (p less than 0.09); end-diastolic pressure less than or equal to 20 vs greater than 20 mm Hg (p less than 0.08). Late survival was not significantly different between pre-AVR functional class I and II vs class III and IV; LV end-diastolic volume index greater than or equal to 210 vs less than 210 ml/m2; LV end-systolic volume index greater than or equal to 110 vs less than 110 ml/m2; and LV mass greater than or equal to 240 vs less than 240 gm/m2. With ejection fraction greater than or equal to 0.50 there was only one operative death (functional class IV) and no late cardiac deaths. Thus late survival following aortic valve replacement for severe isolated aortic regurgitation is better predicted preoperatively by the LV systolic pump function variables of ejection fraction and cardiac index than by LV diastolic parameters and clinical status.