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

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.

Angiotensin-converting enzyme inhibitor captopril prevents volume overload cardiomyopathy in experimental chronic aortic valve regurgitation

The efficacy of angiotensin-converting enzyme inhibitors (ACEIs) in the treatment of chronic aortic regurgitation (AR) is not well established and remains controversial. The mechanisms by which ACEIs may protect against left-ventricular (LV) volume overload are not well understood, and clinical trials performed until now have yielded conflicting results. This study was therefore performed to assess the effectiveness of two different doses of the ACEI captopril in a rat model of chronic AR. We compared the effects of a 6-month low-dose (LD) (25 mg/kg) or higher dose (HD) (75 mg/kg) treatment with captopril on LV function and hypertrophy in Wistar rats with severe AR. Untreated animals developed LV eccentric hypertrophy and systolic dysfunction. LD treatment did not prevent hypertrophy and provided modest protection against systolic dysfunction. HD treatment preserved LV systolic function and dimensions and tended to slow hypertrophy. The cardiac index remained high and similar among all AR groups, treated or not. Tissue renin-angiotensin system (RAS) analysis revealed that ACE activity was increased in the LVs of AR animals and that only HD treatment significantly decreased angiotensin II receptor mRNA levels. Fibronectin expression was increased in the LV or AR animals, but HD treatment almost completely reversed this increase. The ACE inhibitor captopril was effective at high doses in this model of severe AR. These effects might be related to the modulation of tissue RAS and the control of fibrosis.

Aortic valve replacement in patients with impaired ventricular function

BACKGROUND

Patients with reduced ventricular function undergoing aortic valve replacement have increased operative risks, but the impact of valvular pathophysiology and other risk factors has not been clearly defined.

METHODS

From June 1992 through June 2002, 1,402 consecutive patients underwent isolated aortic valve surgery with or without coronary artery bypass grafting; of these patients, 416 had an ejection fraction less than 40% and are the subject of this report. These patients (mean age, 68.6) had severe stenosis (62.5%), severe regurgitation (30.3%), or mixed disease (7.2%). Aortic valve replacement plus coronary artery bypass grafting was performed in 48.4% of patients, and 27% had previous cardiac surgery. Follow-up included echocardiography and survival analysis.

RESULTS

Hospital mortality was 10.1% (42 of 416), with no difference between aortic stenosis (9.6%) and regurgitation (11.1%). Multivariate analysis revealed that age (p = 0.002) and renal disease (odds ratio = 4.2; 95% confidence interval, 1.9 to 9.3; p = 0.001) were independently associated predictors of mortality. Valvular pathophysiology had no impact on mortality. Peripheral vascular disease, multivessel coronary disease, and renal disease were associated risks for any postoperative complication. Peripheral vascular disease (odds ratio = 12.3, p = 0.02), history of cerebrovascular disease (odds ratio = 4.8, p = 0.038), and diabetes (odds ratio = 2.7, p = 0.04) were associated risks for stroke. The ejection fraction was more than 40% in 52% of the patients who had postoperative echocardiography (mean follow-up, 6 months). Actuarial survival revealed no difference between pathophysiologic groups.

CONCLUSIONS

Aortic valve surgery in patients with impaired ventricular function carries an acceptable operative risk that can be stratified by age and comorbidities. The type of valvular pathophysiology does not significantly affect mortality.

Left ventricular response to sustained volume overload from chronic aortic valve regurgitation in rats

OBJECTIVES

Aortic regurgitation (AR) induces left ventricular (LV) eccentric hypertrophy in response to chronic volume overload. Patients suffering from this disease often remain asymptomatic for decades before progressive LV dysfunction develops silently. Because of this slow evolution, large clinical trials with long-term follow-up on subjects with chronic AR are hard to perform. To overcome this problem, animal models have been developed in the past but results were very heterogeneous.

METHODS

Helped by echocardiography, we refined a known technique to induce homogeneous degrees of severe AR in Wistar-Kyoto rats. The effects on LV function without treatment and with nifedipine (25 mg/kg daily) (a drug currently recommended in humans with chronic AR) were evaluated by echocardiography.

RESULTS

Over 6 months, nontreated animals developed progressive LV dilatation and eccentric hypertrophy, characteristic of chronic LV volume overload. The animals also developed progressive LV systolic dysfunction, mimicking closely the evolution of the disease in humans. Abnormal filling parameters were also detected in the majority of animals. Systolic and diastolic abnormalities were prevented but only partially in the group treated with nifedipine.

CONCLUSION

This model can be used to study chronic AR and LV dysfunction associated with the disease. Nifedipine seems to protect the LV against chronic volume overload but only partially. Treatment strategies currently used in humans deserve further investigation.

Indications for surgery for aortic regurgitation

Aortic valve replacement for isolated aortic regurgitation (AR) is usually not indicated unless the regurgitation is severe. However, not all patients with severe AR require aortic valve replacement. This review focuses on the causes of AR and the pathophysiology of acute versus chronic AR, and the attendant adaptive mechanisms of the left ventricle that ultimately determine their different natural histories. Aortic valve surgery must be performed in a timely manner to prevent cardiac death, ameliorate symptoms, and limit late postoperative excess mortality.

Stentless aortic valves as an alternative to homografts for valve replacement in active infective endocarditis complicated by ring abscess

BACKGROUND

The valve substitute of choice in active infective aortic valve endocarditis complicated by annulus abscess in our institution is the cryopreserved homograft. To avoid implantation of any prosthetic material, the Shelhigh No-React stentless valves and conduits may be considered an alternative when no suitable homograft is available.

METHODS

Between March 1986 and January 2001, 452 homografts were implanted in the aortic position. From January 2000 to August 2001, 75 Shelhigh No-React prostheses were implanted at our institution. In 25 consecutive patients (study group) with aortic annulus abscess, urgent aortic valve replacement with the Shelhigh SuperStentless and Stentless Aortic Valve Conduit was undertaken. Patients (16 male, 9 female; age, 49 +/- 19 years) were studied with follow-up until March 2002. The control group comprised 68 consecutive historical patients (46 male, 22 female; age, 53 +/- 14.4 years) with similar disease treated between January 1997 and December 1999 in whom an aortic homograft was implanted. This group was also followed up until March 2002. Demographic data and preoperative characteristics of the patients were without significant differences. Patients were studied by echocardiography.

RESULTS

Sixty-day mortality was 16% (11 patients) in the control group compared with 12% (3 patients) in the study group. Recurrent infection occurred in 4% in both groups. The instantaneous and mean Doppler gradients yielded no significant differences (19.4 +/- 10.4 mm Hg and 11.8 +/- 5.7 mm Hg versus 18.2 +/- 8.7 mm Hg and 10.9 +/- 5.3 mm Hg, respectively). The mean effective orifice area calculated from Doppler flow velocity for the stentless valve was 2.3 +/- 0.6 cm2. Preoperative evaluation of left ventricular dimensions and global left ventricular systolic function did not vary significantly between the two groups. However, postoperatively evaluated left ventricular end-diastolic diameter dimensions in the study group were significantly smaller than those in the control group (47.6 +/- 7.9 mm versus 56 +/- 9.5 mm; p = 0.05). Ejection fraction was similar in both groups (56.2% +/- 12.8% for the study [Shelhigh] and 52.6% +/- 16.8% for the control [homograft] group).

CONCLUSIONS

Our experience with both the Shelhigh No-React SuperStentless and Stentless Aortic Valve Conduit in patients with native or prosthetic aortic valve endocarditis appears to demonstrate good results, similar to those of cryopreserved homografts. Ease of implantation and favorable effective orifice area and pressure gradients, as well as the No-React anticalcification treatment, are promising factors.

Enhanced method for predicting left ventricular reverse remodeling after surgical repair of aortic regurgitation: application of ultrasonic tissue characterization

To predict left ventricular (LV) reverse remodeling after surgical repair of aortic regurgitation, we examined 30 patients with aortic regurgitation accompanying LV dilatation by myocardial tissue characterization with integrated backscatter method. Before and after operation, the magnitude of cyclic variation of integrated backscatter (CVIB) was obtained from anterior septum and posterior wall, and averaged value was calculated in each patient. Before operation, LV end-diastolic dimension, fractional shortening, and LV end-diastolic pressure were not significantly different between the patients with (group GR) and without (group PR) decreased LV end-diastolic dimension after operation. Under these conditions, CVIB, which was 9.6 +/- 1.0 dB from healthy volunteers, was significantly greater in group GR, 5.7 +/- 1.4 dB, than that in group PR, 3.8 +/- 0.8 dB (P =.0003). The patients with CVIB >/= 4 before operation were expected to have reverse remodeling after operation with a sensitivity of 79%, a specificity of 82%. These data indicate that preoperative CVIB from the left ventricle provides pivotal information for predicting reverse remodeling after operation for aortic regurgitation in addition to the conventional echocardiographic parameters.

Outcome following mitral valve replacement in patients with mitral stenosis and moderately reduced left ventricular ejection fraction

BACKGROUND

Some patients with mitral stenosis (MS) have moderately reduced left ventricular (LV) ejection fraction (EF), due to either depressed myocardial contractility or alterations in loading conditions. The effect of moderately reduced LV EF on outcome after mitral valve replacement (MVR) is not known.

METHODS

We studied 16 consecutive patients with LV EF < or = 0.50 and MS without significant mitral regurgitation or other valvular or coronary artery disease (Group I). We selected four controls with LV EF >0.50 for each patient, matched for time of surgery (Group II, n=64). Mean EF in Groups I and II was 0.45 and 0.66, respectively. We compared short- and long-term outcome between the two groups.

RESULTS

There were no perioperative deaths. Group I patients had a higher incidence of in-hospital postoperative heart failure (25% vs. 6%, P=0.02). Mean follow-up was 9 years in both groups. Mean New York Heart Association class improved from 2.4 to 1.7 in both groups. Group I patients had a higher incidence of heart failure deaths (13% vs. 2%, P=0.03) and admissions (40% vs. 13%, P=0.01). There were, however, no differences between Groups I and II in overall mortality (27% vs. 21%), rate of cardiac admissions (69% vs. 53%), or mean Specific Activity Scale Score (2.5 vs. 2.5).

CONCLUSIONS

Although patients with MS and moderately reduced LV EF are at higher risk for heart failure after MVR, overall mortality is not different from that of patients with normal EF. Moderate depression of LV EF should not be a contraindication to MVR for MS.

Aortic insufficiency: Indications for surgery in children

The goals of surgery in children with chronic aortic insufficiency are to prevent irreversible left ventricular dysfunction and to provide for long-term survival. In the past, surgical options included placement of a mechanical valve, a porcine bioprosthesis, or an aortic valve homograft. Complications from these options include thromboembolism, prosthetic valve endocarditis, limited durability, and lack of growth potential. The increasing utilization of the Ross procedure to treat chronic aortic insufficiency has led to new interest in the question of when to operate on a regurgitant aortic valve. This review focuses on the pathophysiology of aortic insufficiency and the invasive and noninvasive preoperative indices that may indicate the optimal time for aortic valve surgery in the pediatric population. Copyright 1998 by W.B. Saunders Company

Aortic Regurgitation

Left ventricular (LV) systolic function is an important determinant of long-term prognosis in patients with chronic aortic regurgitation (AR). Impaired LV systolic function identifies a group of patients who are at risk of developing postoperative congestive heart failure and death after aortic valve replacement (AVR). Hence, asymptomatic patients with definite evidence of impaired LV function should undergo operation without waiting for the development of symptoms or more severe LV dysfunction. Among asymptomatic patients with normal LV systolic function (normal ejection fraction), prognosis is excellent, and fewer than 5% per year require surgery because of symptom development or LV dysfunction. Patients likely to require surgery can be identified on the basis of age, severity of LV dilatation, and progressive increase in LV dimensions or decrease in resting ejection fraction during the course of serial follow-up studies. Afterload-reducing therapy in asymptomatic patients with severe AR and normal LV function has beneficial hemodynamic effects; chronic therapy may reduce the likelihood of symptoms or LV systolic dysfunction. Aortic valve replacement should be performed once significant symptoms develop. In the absence of important symptoms, the operation should also be performed in patients with AR who manifest consistent and reproducible evidence of either LV contractile dysfunction at rest or extreme LV dilatation. Noninvasive imaging should play a major role in evaluation. An important clinical decision--such as recommending AVR in the asymptomatic patient--should not be based on a single echocardiographic or radionuclide angiographic measurement. When these data consistently indicate impaired contractile function at rest or extreme LV dilatation on repeat measurement, 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.

Echocardiographic predictors of clinical outcome in patients with left ventricular dysfunction enrolled in the SOLVD registry and trials: significance of left ventricular hypertrophy. Studies of Left Ventricular Dysfunction

OBJECTIVES

To assess the relation of left ventricular (LV) and left atrial (LA) dimensions, ejection fraction (EF) and LV mass to subsequent clinical outcome of patients with LV dysfunction enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) Registry and Trials.

BACKGROUND

Data are lacking on the relation of LV mass to prognosis in patients with LV dysfunction and on the interaction of LV mass with other measurements of LV size and function as they relate to clinical outcome.

METHODS

A cohort of 1,172 patients enrolled in the SOLVD Trials (n = 577) and Registry (n = 595) had baseline echocardiographic measurements and follow-up for 1 year.

RESULTS

After adjusting for age, New York Heart Association (NYHA) functional class, Trial vs. Registry and ischemic etiology, a 1-SD difference in EF was inversely associated with an increased risk of death (risk ratio, 1.62; p = 0.0008) and cardiovascular (CV) hospitalization (risk ratio, 1.59; p = 0.0001). Consequently, the other echo parameters were adjusted for EF in addition to age, NYHA functional class, Trial vs. Registry and ischemic etiology. A 1-SD difference in LV mass was associated with increased risk of death (risk ratio of 1.3, p = 0.012) and CV hospitalization (risk ratio of 1.17, p = 0.018). Similar results were observed with the LA dimension (mortality risk ratio, 1.32; p < 0.02; CV hospitalizations risk ratio, 1.18; p < 0.04). Likewise, LV mass > or =298 g and LA dimension > or =4.17 cm were associated with increased risk of death and CV hospitalization. An end-systolic dimension >5.0 cm was associated with increased mortality only. A protective effect of EF was noted in patients with LV mass > or =298 g (those in the group with EF >35% had lower mortality) but not in the group with LV mass <298 g.

CONCLUSIONS

In patients with LV dysfunction enrolled in the SOLVD Registry and Trials, increasing levels of hypertrophy are associated with adverse events. A protective effect of EF was noted in patients with LV mass > or =298 g (those in the group with EF >35% fared better) but not in the group with LV mass <298 g. These data support the development and use of drugs that can inhibit hypertrophy or alter its characteristics.

[Nuclear cardiology: technical bases and clinical applications]

Although the role of nuclear cardiology is currently well consolidated, the addition of new radiotracers and modern techniques makes it necessary to continuously update the requirements, equipment and clinical applications of these isotopic tests. The characteristics of the radioisotopic drugs and examinations presently used are explained in the first part of this text. In the second, the indications of them in diagnostic and prognostic evaluation of the different coronary diseases are presented.

Mortality and need for reoperation in patients with mild-to-moderate asymptomatic aortic valve disease undergoing coronary artery bypass graft alone

BACKGROUND

Patients presenting for coronary artery bypass graft (CABG) surgery may have concurrent asymptomatic aortic stenosis (AS) or aortic insufficiency (AI). This retrospective study was performed to evaluate outcomes in patients with aortic valve disease undergoing CABG with or without aortic valve replacement (AVR).

METHODS

Study groups included 414 patients undergoing combined AVR and CABG (AVR-CABG group) and 62 patients with asymptomatic mild-to-moderate AS, AI, or both undergoing CABG but not AVR (CABG group). End points included 30-day mortality rate, time to cardiac mortality, time to all-cause mortality, and time to aortic valve reoperation. Reoperation refers to surgery for replacement of the native aortic valve in the CABG group or replacement of the prosthetic aortic valve in the AVR-CABG group. Important patient characteristics affecting outcomes were determined by using Cox proportional-hazard analysis. These variables were then included in multivariable analyses by using logistic regression analysis and Cox proportional-hazard modeling to compare outcomes between each patient group.

RESULTS

No difference was seen in any of the mortality end points between the CABG group and the AVR-CABG group after controlling for significant differences between the groups. However, the need for reoperation for AVR was significantly higher for the CABG group than the AVR-CABG group. For patients followed for up to 6 years, the estimated need for aortic valve reoperation was 24.3% in the CABG group versus 3% in the AVR-CABG group.

CONCLUSION

On the basis of these results, patients with asymptomatic AS or AI should be considered for AVR at the time of CABG.

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.

MRI-radiofrequency tissue tagging in patients with aortic insufficiency before and after operation

BACKGROUND

Magnetic resonance imaging tissue tagging is a relatively recent methodology that describes ventricular systolic function in terms of intramyocardial ventricular deformation. Because the analysis involves the use of many intramyocardial points to describe systolic deformation, it is theoretically more sensitive at describing subtle differences in regional myocardial fiber shortening when compared with conventional measures of ventricular function such as wall thickening. The objectives of this study were (1) to define sensitive indices of ventricular systolic deformation to assist the clinician in the surgical evaluation of patients with aortic insufficiency, and (2) to quantify differences in regional systolic deformation before and after surgery for aortic insufficiency.

METHODS

Magnetic resonance imaging with tissue tagging was performed on 10 normal volunteers and 8 patients with chronic severe aortic insufficiency. Follow-up postoperative studies (5.4+/-1.1 months) were obtained in 6 patients who underwent Ross procedure (1 patient), David procedure (1), and St. Jude aortic valve replacement (4).

RESULTS

There was no significant difference in fractional area change, overall circumferential shortening, or overall radial thickening among the normal group, the preoperative aortic insufficiency group, or the postoperative aortic insufficiency group. However, on a regional basis, there was a decrease in posterior wall circumferential strains in the postoperative aortic insufficiency group (29%+/-13% preoperative aortic insufficiency (n=6) versus 24%+/-12% postoperative aortic insufficiency (n=6), p=0.02).

CONCLUSIONS

On regional analysis, there was a small but significant decrease in posterior wall circumferential shortening after operation. Magnetic resonance imaging tissue tagging is a sensitive and clinically applicable method of quantifying regional ventricular wall function before and after intervention for aortic insufficiency.

Prediction of indications for valve replacement among asymptomatic or minimally symptomatic patients with chronic aortic regurgitation and normal left ventricular performance

BACKGROUND

Optimal criteria for valve replacement are unclear in asymptomatic/minimally symptomatic patients with aortic regurgitation (AR) and normal left ventricular (LV) performance at rest. Moreover, previous studies have not assessed the prognostic capacity of load-adjusted LV performance ("contractility") variables, which may be fundamentally related to clinical state. Therefore, 18 years ago, we set out to test prospectively the hypothesis that objective noninvasive measures of LV size and performance and, specifically, of load-adjusted variables, assessed at rest and during exercise (ex), could predict the development of currently accepted indications for operation for AR.

METHODS AND RESULTS

Clinical variables and measures of LV size, performance, and end-systolic wall stress (ESS) were assessed annually in 104 patients by radionuclide cineangiography at rest and maximal ex and by echocardiography at rest; ESS was derived during ex. During an average 7.3-year follow-up among patients who had not been operated on, 39 of 104 patients either died suddenly (n = 4) or developed operable symptoms only (n = 22) or subnormal LV performance with or without symptoms (n = 13) (progression rate=6.2%/y). By multivariate Cox model analysis, change (delta) in LV ejection fraction (EF) from rest to ex, normalized for deltaESS from rest to ex (deltaLVEF-deltaESS index), was the strongest predictor of progression to any end point or to sudden cardiac death alone. Unadjusted deltaLVEF was almost as efficient. Symptom status modified prediction on the basis of the deltaLVEF-deltaESS index. The population tercile at highest risk by deltaLVEF-deltaESS progressed to end points at a rate of 13.3%/y, and the lowest-risk tercile progressed at 1.8%/y.

CONCLUSIONS

Currently accepted symptom and LV performance indications for valve replacement, as well as sudden cardiac death, can be predicted in asymptomatic/minimally symptomatic patients with AR by load-adjusted deltaLVEF-deltaESS index, which includes data obtained during exercise.

Comparison of post-stress ejection fraction and relative left ventricular volumes by automatic analysis of gated myocardial perfusion single-photon emission computed tomography acquired in the supine and prone positions

BACKGROUND

We have previously described an automatic method for measuring left ventricular ejection fraction (LVEF) for myocardial perfusion single-photon emission computed tomography (SPECT). The repeatability of this method has not been previously described.

METHODS AND RESULTS

This study compares LVEF and relative end-systolic and end-diastolic volumes assessed from myocardial perfusion SPECT by our automatic method in 180 consecutive patients undergoing gated myocardial perfusion SPECT with injection of 99mTc-labeled sestamibi in whom the acquisitions were performed sequentially in supine and prone positions. The algorithm operated completely automatically in the prone and supine positions in 178 of the 180 patients. Very high correlations were observed for LVEF (r = 0.93), relative left ventricular end-systolic volume (r = 0.98), and relative left ventricular end-diastolic volume (r = 0.97). The mean paired absolute difference between LVEFs in the prone and supine position was 3.8+/-3.2, for left ventricular end-systolic volume was 4.9+/-4.8 ml, and for left ventricular end-diastolic volume was 7.4+/-6.7 ml. When patients were classified by the extent and severity of stress perfusion defect, there was no significant difference in repeatability for the measurements in any category.

CONCLUSIONS

Our algorithm for automatic quantification of LVEF and relative end-systolic and end-diastolic volumes from gated 99mTc sestamibi myocardial perfusion SPECT is repeatable. When performed in the prone position, values of ejection fractions and ventricular volumes are essentially identical to those obtained in the supine position.

Late survival after valve operation in patients with left ventricular dysfunction

BACKGROUND

Left ventricular dysfunction is a predictor of hospital mortality after cardiac valve operation. We evaluated late survival in a large cohort of these patients.

METHODS

From 1980 to 1993, 257 patients with a preoperative ejection fraction of 0.40 or less underwent aortic (n = 177), mitral (n = 72), or combined (n = 8) valve operation, with or without concomitant coronary artery bypass grafting.

RESULTS

Hospital mortality was 12.5%. Follow-up was 98% complete. Logistic regression analysis showed that an ejection fraction of less than 0.30, mitral regurgitation, concomitant coronary artery bypass grafting, emergency operation, and reoperation were independent correlates of hospital mortality (all at p < 0.05). Kaplan-Meier survival curves of the 220 hospital survivors showed a 65% 5-year survival. Multivariate analysis revealed preoperative use of diuretics, male sex, reoperation, age exceeding 60 years, and aortic regurgitation to be independent predictors of poor late outcome (all at p < 0.05).

CONCLUSIONS

The liability of left ventricular dysfunction with regard to diminished long-term survival is not completely reversed by valve operation. If operation is not performed before left ventricular dysfunction develops, postoperative medical treatment of these dilated, remodeled ventricles should be considered.

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.

Recipient selection and management before cardiac transplantation

Cardiac transplantation is a proven, effective therapy for selected patients with end-stage congestive heart failure. Recipient selection is performed by a multidisciplinary team consisting of transplant physicians and surgeons. Clinicians responsible for patient assessment must establish the severity of cardiac dysfunction, formulate a prognosis, and stratify patients according to risk for mortality. Patients whose survival and quality of life are most limited without cardiac transplantation are candidates for therapy. The scarcity of organ donors makes careful screening of potential recipients necessary to identify those individuals most likely to obtain a long-term benefit. Recipient selection criteria and management strategies are evolving because of extended waiting times and high mortality caused by the lack of sufficient numbers of donors. Alternative therapies should be applied wherever possible.

Relation of ultra-low frequency heart rate variability to the clinical course of chronic aortic regurgitation

We examined the relation of the standard deviation of the 5-minute mean RR intervals over 24 hours (SDANN), a measure of ultra-low frequency heart rate variability (HRV) (<0.0033 Hz), and other measures of HRV to clinical outcome events in 50 asymptomatic or minimally symptomatic patients with chronic severe aortic regurgitation (AR) who underwent ambulatory electrocardiography as part of a prospective study of the natural history of regurgitant valvular diseases. At entry, all patients were in sinus rhythm and had New York Heart Association functional class I or minimal II congestive heart failure, with left ventricular (LV) ejection fraction > or = 45% and LV end-diastolic dimension > or = 5.5 cm in women and > or = 5.9 cm in men. End points were defined as progression to aortic valve replacement (n = 19) or sudden cardiac death (n = 1) during the mean follow-up period of 8.1 +/- 3.8 years. With the median SDANN of 145 ms as a partition value, the average annual risk of end-point events in patients with low SDANN was significantly greater than the event rate in patients with high SDANN (11%/year vs 2%/year, p <0.0003). In multivariate analysis, reduced SDANN was associated with end-point events independent of LV function, LV end-systolic dimension, and symptom status (p = 0.001). We conclude that reduced ultra-low frequency HRV measured as SDANN is strongly related to progression to valve surgery in asymptomatic and minimally symptomatic patients with chronic AR.

Quantitative Stress Echocardiography in Chronic Aortic and Mitral Regurgitation

It was the purpose of the present study to prove the feasibility and reliability of quantitative stress-echocardiography as an alternative method to radionuclide angiography (RNA) in chronic regurgitant valvular lesions. Echocardiography and RNA are most commonly used to obtain various left ventricular (LV) morphometric and functional parameters that have been postulated to predict long-term prognosis in patients with aortic and mitral valvular regurgitation. Supine bicycle ergometry with a workload ranging from 25-250 Watts was used to evaluate stress dependent LV volumes and ejection fractions (EFs) in patients with pure aortic (n = 18) and mitral regurgitation (n = 14). Most patients (23/32) underwent simultaneous right heart catheterization. Echocardiographic EFs were validated by RNA with good correlations (r = 0.81, P < 0.01). Patients with aortic regurgitation and functional class I/II (9), had a significant increase in EF during exercise (60%-67%, P < 0.001) and a reduction in end-systolic volume (71-52 mL, P < 0.01). In comparison, patients with class III symptoms (9), had a drop in EF (53%-49%, P < 0.01), had larger baseline end-systolic volume (104 mL, P = NS), which did not decrease during stress (104 vs 107 mL, P = NS). In patients with chronic mitral regurgitation baseline and exercise EF did not differ between class I/II (6) and class III (8), however, mildly symptomatic patients increased from 57%-67%, (P < 0.01) versus patients in class III (65% vs 69%, P = NS). Stroke volume index was not different at baseline (44 vs 33 mL/m(2), P = NS); however, there were significant differences during exercise (70 vs 41 mL/m(2), P = 0.05). Quantitative stress-echocardiography is a noninvasive and safe alternative method to RNA, which allows reliable calculation of stress dependent LV volumes and EF. Determination of end-systolic volumes may be of additional prognostic value. The combination of a high baseline EF and low stroke volume index with the inability to improve during exercise might reflect early stages of impaired LV function in patients with severe mitral regurgitation.

M-mode echocardiography in aortic stenosis. Clinical correlates and prognostic significance after valve replacement

To relate preoperative findings at M-mode echocardiography to preoperative clinical and haemodynamic status and to identify possible echocardiographic risk factors for mortality after aortic valve replacement (AVR), 250 patients with AVR for aortic stenosis (AS) were studied. In follow-up averaging 3.2 years there were 22 early (< 30 days) and 23 late deaths. Rising NYHA function class and cardiothoracic index, and left ventricular (LV) failure were related to rising LV end-diastolic and end-systolic diameter index (EDDI, ESDI), and to increasing LV muscle mass index and decreasing fractional shortening (FS). High peak-to-peak systolic aortic valve gradient and LV end-systolic pressure were related to small dimensions of LV with increased FS and posterior wall thickness (PWTh). EDDI < or = 20 mm/m2 and increasing PWTh were independent risk factors for early mortality. Patients with EDDI < or = 20 mm/m2 had normal or supranormal FS. PWTh was the only independent risk factor in long-term survival: 5-year rates being 81 +/- 6%, 94 +/- 3% and 85 +/- 7% for PWTh < or = 13, 14-17 and > or = 18 mm, respectively (p = 0.03). Prevalence of concomitant coronary artery disease (CAD) rose with decreasing PWTh. Angina pectoris in non-CAD patients was related to very high PWTh. Subnormal EDDI was associated with poor surgical outcome, and dilated, poorly contracting LV with congestive heart failure prior to AVR. The degree of LV hypertrophy seemed to be the dominant risk factor, but confounders included myocardial ischaemia due to CAD in low-grade hypertrophy or to hypertrophy per se. A hypothetically confounding factor is the reversibility potential of moderate or severe LV hypertrophy following AVR.

Combined rest and exercise electrocardiographic repolarization findings in relation to structural and functional abnormalities in asymptomatic aortic regurgitation

The relationship of combined rest and exercise electrocardiographic (ECG) repolarization abnormalities to left ventricular geometry and function was examined in 48 patients with asymptomatic chronic pure aortic regurgitation and no recent use of digitalis. Echocardiographic and radionuclide cineangiographic findings were compared in groups defined by the presence or absence of the "strain" pattern of repolarization abnormality on the resting ECG and also by the presence or absence of standard positive repolarization changes during upright treadmill exercise ( > 0.1 mV additional horizontal or downsloping ST depression). These hierarchic groups demonstrated trends toward progressively abnormal left ventricular dimensions, mass, wall stress, and change in ejection fraction with exercise. Although the presence of the strain pattern on the resting ECG alone was most strongly correlated with underlying functional and geometric abnormalities, an abnormal exercise test response was independently associated with abnormal left ventricular systolic dimension. The large group of patients with no symptoms and normal resting repolarization had only 0% to 4% prevalences of markedly increased systolic dimension (> 55 mm), reduced ejection fraction at rest (< 45%), or reduced ejection fraction during exercise (< 40%), whereas the small group of patients with abnormal resting repolarization and a positive exercise test response had 50% to 83% prevalences of these findings. These data suggest a possible role for rest and exercise ECG in the serial evaluation of patients with aortic regurgitation.

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.

Echocardiographic results after repair of incompetent bicuspid aortic valves

INTRODUCTION

Valve-related complications and the necessity of anticoagulation after aortic valve replacement have led to new operative techniques for correction of aortic insufficiency (AI). Fourteen patients with bicuspid aortic valves and significant AI underwent valve repair.

METHODS

Transthoracic echocardiography was performed preoperatively and 1 week postoperatively and in 10 patients who have come to follow-up so far. Operative procedures were triangular resection of one leaflet in all patients. Five patients had pericardial patch plasty in addition.

RESULTS

Mean AI decreased significantly from grade 3.5 +/- 0.1 preoperatively to 0.5 +/- 0.1 postoperatively (p < 0.001). Postoperatively, 10 patients had no or trivial AI (0 to 0.5), and 2 patients had mild AI (1 to 1.5). Within the first week, 2 patients were reoperated on after echocardiography established significant AI. Ventricular dimensions decreased from preoperative to postoperative and were normal after 1 year. At follow-up, 7 patients show no change of AI; in 3 patients AI increased to moderate because of dilatation of the sinus of Valsalva or the sinotubular junction.

CONCLUSIONS

Reconstruction of bicuspid aortic valves is feasible with good early results. Echocardiography shows that asymmetric sinuses may lead to early perioperative failures and postoperative dilatation of the proximal aorta to increasing AI. Operative techniques may have to consider the pathology of the proximal aorta.

Clinical outcome of severe asymptomatic chronic aortic regurgitation: a long-term prospective follow-up study

One hundred one patients with asymptomatic chronic severe aortic regurgitation and normal ejection fraction were monitored for up to 10 years (mean 55.4 +/- 33.5 months). Predefined surgical indications were the development of cardiac symptoms or the documentation of impaired basal left ventricular function. During the follow-up period there were no cardiac deaths; 14 patients needed surgery, 8 because of development of symptoms and 6 because of left ventricular impairment. The risk of surgery was 12% at 5 years and 24% at 10 years. Baseline end-systolic diameter > 50 mm and radionuclide ejection fraction < 60% were independent predictors or either cardiac symptoms or left ventricular dysfunction. In patients needing surgery, a pattern of progressive left ventricular dilatation was demonstrated. There were no deaths during surgery, and echocardiographic and radionuclide parameters normalized in the first year of follow-up. Our data confirm that the prognosis of severe aortic regurgitation in patients with no symptoms is good and that the occurrence of asymptomatic left ventricular dysfunction is an uncommon event. Surgery can be safely postponed until the appearance of cardiac symptoms or the documentation of left ventricular dysfunction at rest.

Use of the left ventricular peak systolic pressure/end-systolic volume ratio to predict symptomatic improvement with valve replacement in patients with aortic regurgitation and enlarged end-systolic volume

OBJECTIVES

This study was designed to assess the left ventricular peak systolic pressure/end-systolic volume (PSP/ESV) ratio in predicting symptomatic improvement with valve replacement in patients with aortic regurgitation and enlarged left ventricular volume.

BACKGROUND

Patients with aortic regurgitation and a left ventricular end-systolic volume < or = 60 ml/m2 show symptomatic improvement with valve replacement, whereas the response of those with an enlarged end-systolic volume > 60 ml/m2 is mixed. Most benefit, but some do not. Valve replacement appears to help those whose end-systolic volume is enlarged because of excessive left ventricular afterload but appears to have little or no effect in those whose end-systolic volume is enlarged because of depressed left ventricular contractility.

METHODS

We studied 27 patients (21 men and 6 women aged 18 to 72 years) with moderate or severe aortic regurgitation, no other cardiovascular abnormalities and left ventricular end-systolic volume > 60 ml/m2. In this group we assessed the ability of preoperative variables routinely measured at cardiac catheterization to predict symptomatic improvement with valve replacement.

RESULTS

Of the 27 subjects, 1 (4%) died 51 days postoperatively. Six months postoperatively, symptoms had lessened in 17 patients (63%), were unchanged in 8 (29%) and had worsened in 1 (4%). By multivariate analysis, the PSP/ESV ratio was the strongest predictor of both functional class 6 months postoperatively (p = 0.026) and change in functional class from before operation to 6 months postoperatively (p = 0.033). By 6 months after valve replacement, all patients with a ratio > or = 1.72 mm Hg/ml per m2 were in functional class I or II; in contrast, of those with a ratio < 1.72 mm Hg/ml per m2, 31% were in functional class III, and 1 (8%) had died.

CONCLUSIONS

The PSP/ESV ratio may help to predict which patients with aortic regurgitation and enlarged left ventricular end-systolic volume will have symptomatic improvement with valve replacement.

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.

Surgical timing in aortic regurgitation: left ventricular function analysis by contractility score

In 32 patients with aortic regurgitation, angiographic evaluation of global left ventricular performance before and after aortic valve replacement was carried out by means of a computer-analyzed contractility scoring system. A strong correlation was detected between the preoperative and postoperative contractility score. Postoperatively, the score decreased in all but 3 patients, becoming normal or near normal in 21 of 27 patients whose preoperative value had been less than 40. However, all 5 patients with a preoperative contractility score of 40 or greater exhibited a persistently elevated score after operation that indicated the presence of irreversible contractile dysfunction. Patients in groups A and B (preoperative score, 0 to 40) experienced a good surgical outcome, and at 5-year follow-up were in New York Heart Association functional class I. Patients in group C (preoperative score, > 40) altogether had a very poor surgical outcome, although they did experience a short to midterm period of symptomatic relief. It is important to offer aortic valve replacement to patients with aortic regurgitation before their chances for a good functional result are lost. The computer-analyzed contractility score may be a useful index for determining the optimal timing of operation in these patients, particularly those who show features consistent with impaired left ventricular function but are asymptomatic and who should undergo aortic valve replacement before symptoms of definitive left ventricular failure develop.

Asymptomatic aortic regurgitation: indications for operation

Left ventricular (LV) systolic function is an important determinant of long-term prognosis in patients with chronic aortic regurgitation. In patients undergoing aortic valve replacement (AVR), those with preoperative LV dysfunction have a greater risk of postoperative congestive heart failure and death than do those in whom preoperative LV systolic function is normal. Patients with preoperative LV dysfunction are not a homogeneous group, however, but may be further stratified according to risk on the basis of the severity of symptoms, exercise intolerance, and temporal duration of LV dysfunction. Hence, asymptomatic patients with reproducible and definite evidence of impaired LV function should undergo operation without waiting for the development of symptoms or more severe LV dysfunction. Among asymptomatic patients with normal LV systolic function (normal ejection fraction and fractional shortening), the prognosis is excellent with only a gradual rate of deterioration during conservative, nonoperative management. The long-term follow-up experience of such patients indicates that the annual mortality rate is less than 0.5% and that less than 4% per year require AVR because symptoms or LV dysfunction at rest develop. Patients likely to require operation over a 10-year period because symptoms or LV dysfunction develop can be identified on the basis of age, severity of LV dilatation by echocardiography, and progressive change in LV dimensions or resting ejection fraction during the course of serial follow-up studies. Patients at risk of sudden death before surgery is performed may be identified by extreme LV dilatation (diastolic dimension > 80 mm, systolic dimension > 55 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of survival and recovery of left ventricular function after aortic valve replacement

To determine factors that influence survival and recovery of ventricular function in patients undergoing aortic valve replacement in the current surgical era, baseline risk factors related to outcome were analyzed in 1,012 consecutive patients undergoing aortic valve replacement between 1983 and 1990. Forty-two percent of patients underwent concomitant coronary bypass. Observed survival probabilities (expressed as 30-day/5-year) were 0.97/0.81 overall, 0.99/0.89 for patients aged less than 70 years, and 0.95/0.74 for patients aged 70 years or greater. Advanced age (p < 0.0001), decreased ejection fraction (p < 0.0001), extent of coronary disease (p < 0.006), smaller prosthetic valve (p < 0.03), and advanced New York Heart Association class (p < 0.04) were incremental risk factors for mortality. In patients with preoperative ventricular dysfunction (ejection fraction < or = 0.45), ejection fraction measured 1.4 years after aortic valve replacement improved in 72% and the mean increment in ejection fraction was 0.175 (95% confidence interval, 0.154 to 0.195). The increment in ejection fraction was greater in female patients than in male patients (p < 0.02) and greater in patients without than with coronary disease (p < 0.02). Female sex (p < 0.02) and lesser extent of coronary disease (p < 0.05) were independent predictors of change in ejection fraction. In all patients, early improvement in ejection fraction conveyed an independent subsequent survival benefit (p < 0.0001). The results of aortic valve replacement in the current era are excellent, and the majority of patients with ventricular dysfunction demonstrate significant improvement. Early improvement in ejection fraction, influenced by coexistent coronary artery disease and sex-associated factors, importantly affects subsequent survival.

Correlates of aortic distensibility in chronic aortic regurgitation and relation to progression to surgery

Aortic distensibility decreases with increasing age. Patients with chronic aortic regurgitation eject a large stroke volume into the proximal aorta. A decrease in distensibility of the aorta may impose a higher afterload on the left ventricule and may contribute to deterioration of left ventricular function over time. Accordingly, aortic distensibility was measured in 33 patients aged 13 to 73 years who had chronic isolated aortic regurgitation with minimal or no symptoms. Ascending aortic diameter was measured 4 cm above the aortic valve by two-dimensional echocardiography and pulse pressure was measured simultaneously by sphygmomanometry. Aortic distensibility was calculated as (Change in aortic diameter between systole and diastole/End-diastolic diameter)/Pulse pressure. Left ventricular systolic wall stress and mass were derived from standard M-mode echocardiographic measurements. Left ventricular volumes and ejection fraction were measured by radionuclide ventriculography. Aortic distensibility decreased logarithmically with increasing age (r = -0.62, p less than 0.001) and also correlated inversely with systolic wall stress, left ventricular mass and end-diastolic volume. Patients who eventually underwent aortic valve replacement for symptoms of left ventricular dysfunction had significantly lower aortic distensibility than did those who did not yet require valve replacement: 0.09 +/- 0.08 vs. 0.22 +/- 0.19 x 1/100 (1/mm Hg) (p less than 0.05). Thus, the reduced aortic distensibility that occurs with increasing age may contribute to the gradual left ventricular dilation and dysfunction seen in patients with chronic aortic regurgitation.

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.

Clinical evaluation of a prospective protocol for the timing of surgery in chronic aortic regurgitation

Out of 160 prospectively followed patients with aortic regurgitation, the clinical courses of 53 patients with pure, severe, and chronic aortic regurgitation and without coronary artery disease who were selected for surgery on the basis of predefined criteria is discussed. Surgical criteria were either unequivocal symptoms or documentation of impaired left ventricular dysfunction (defined as angiographic ejection fraction of less than 50% plus and end-systolic volume index greater than 60 ml/m2). According to preoperative status, patients were divided as follows: 11 asymptomatic patients (group A), 30 patients with moderate (classes II to III) symptoms (group B), and 12 patients with dyspnea at rest and pulmonary edema when first seen (group C). Surgical mortality was one patient (from group C). Late death occurred in four patients (one from group B, three from group C). At the end of follow-up (minimum 1 year, mean 3.6 years) 41 patients were in functional class I, four patients in class II, and one patient in class III. All patients except one in functional classes II and III belonged to group C. Before surgery, patients from groups A and B had similar ventricular dimensions and ejection fractions, whereas patients from group C had larger end-systolic diameters and volumes and lower ejection fractions. End-diastolic and end-systolic diameters decreased significantly at 1 and 2 years after surgery. Patients from group C continued to have dilated hearts as did those patients from groups A and B who had preoperative end-systolic diameters greater than 55 mm.(ABSTRACT TRUNCATED AT 250 WORDS)