Left ventricular function before and following aortic valve replacement

Incremental Value of Global Longitudinal Strain for Confirming Heart Failure-Related Symptoms in Severe Aortic Stenosis

The indications or timing of aortic valve replacement for symptomatic aortic stenosis (AS) are based on a patient's life expectancy and symptoms. However, clinical decision-making may be difficult because symptoms are subjective and cannot be quantitatively assessed and confirmed. This study aimed to evaluate the association between heart failure (HF)-related symptoms and cardiac hemodynamic left ventricular deformations in patients with severe AS using transthoracic echocardiographic assessments of left ventricular global longitudinal strain (LV-GLS). The medical records of patients hospitalized for AS between February 2017 and September 2019 were retrospectively screened. Independent cardiologists analyzed the transthoracic echocardiographic images of a digital echocardiography database. The cohort comprised 177 hospitalized patients with severe AS and no history of HF. The subgroup with HF-related symptoms included 87 patients, whereas that without HF-related symptoms included 90 patients. In 145 patients without atrial fibrillation, the left atrial volume index (LAVI) and LV-GLS were significantly associated with HF-related symptoms (odds ratio 1.033, 95% confidence interval 1.008 to 1.059, p = 0.011 and odds ratio 1.224, 95% confidence interval 1.118 to 1.340, p <0.0001, respectively). Moreover, the combination of brain natriuretic peptide level, LAVI, and LV-GLS showed better diagnostic accuracy than the combination of brain natriuretic peptide level and LAVI (p = 0.005). However, there were no such tendencies in 32 patients with atrial fibrillation. The HF-related symptoms in patients with severe AS were strongly linked to LV-GLS. LV-GLS showed incremental value for confirming HF-related symptoms.

Clinical and Echocardiographic Results of Aortic Valve Replacement in the Failing Ventricle: Do Aortic Stenosis and Aortic Regurgitation Differ?

BACKGROUND

We hypothesized that long-term clinical and echocardiographic recovery of the impaired ventricle from pressure (aortic stenosis [AS]) and volume (aortic regurgitation [AR]) overload would be different after aortic valve replacement (AVR).

METHODS

We compared the results of AVR in patients with a preoperative ejection fraction (EF) of 0.35 or less due to AS, AR, or mixed disease. We constructed a mixed-effects model of EF and left ventricular (LV) end-diastolic diameter (LVEDD) to understand ventricular recovery over the short- (in-hospital), intermediate- (3-6 months), and longer- (>24 months) terms. We sought to identify factors associated with clinical and echocardiographic recovery using multivariable analysis.

RESULTS

Between July 2011 and 2017, 136 patients with a preoperative EF of 0.35 or less and severe AS (n = 83), severe AR (n = 18), or mixed AS and AR (n = 35) underwent AVR. There were 2 (1.5%) early deaths in the AS group. Survival at 1, 2, and 5 years did not differ between groups. Baseline EF did not differ between the groups but improved with markedly different trajectory and time course in the AS, AR, and mixed groups over time. LVEDD regressed in all patient cohorts, following a different pattern for AS and AR. Baseline EF and LVEDD predicted the long-term fate of the LV but did not determine survival. We identify factors associated with long-term survival.

CONCLUSIONS

The pattern of LV recovery appears to be early in AS and delayed in AR. Baseline clinical factors, rather than echocardiographic status of the LV, appear to determine late survival.

Adverse remodeling in atrial fibrillation following isolated aortic valve replacement surgery

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia with adverse clinical outcomes. Aortic valve replacement (AVR) is one of the most frequently performed cardiac surgeries, although there is scarce evidence on arrhythmic outcomes. We aimed to evaluate AF during the first year post- isolated aortic valve replacement surgery and its clinical, analytical, and echocardiographic predictors.

METHODS

Severe aortic stenosis patients with no prior atrial fibrillation submitted to isolated aortic valve replacement surgery were included in our study, of which 316 remained in sinus rhythm and 24 developed AF. We performed logistic regression searching for AF predictors and a longitudinal comparison between pre and post-operative echocardiographic data.

RESULTS

Postoperative AF (POAF), diabetes, and follow-up indexed Left Atrium Diameter (iLAD) were significantly higher in the group of patients developing AF. POAF and iLAD were independent AF predictors at follow-up. No differences between groups were found regarding baseline and follow-up echocardiographic data except for indexed Left Ventricle End-diastolic Diameter (LVED), which failed to decrease after surgery in the AF group.

CONCLUSIONS

POAF and iLAD independently predicted AF at 1 year following isolated AVR surgery in aortic stenosis patients with no AF history. iLVED did not decrease significantly at follow-up in AF patients, possibly reflecting adverse ventricular remodeling.

Pathophysiological coronary and microcirculatory flow alterations in aortic stenosis

Regulation of coronary blood flow is maintained through a delicate balance of ventriculoarterial and neurohumoral mechanisms. The aortic valve is integral to the functions of these systems, and disease states that compromise aortic valve integrity have the potential to seriously disrupt coronary blood flow. Aortic stenosis (AS) is the most common cause of valvular heart disease requiring medical intervention, and the prevalence and associated socio-economic burden of AS are set to increase with population ageing. Valvular stenosis precipitates a cascade of structural, microcirculatory, and neurohumoral changes, which all lead to impairment of coronary flow reserve and myocardial ischaemia even in the absence of notable coronary stenosis. Coronary physiology can potentially be normalized through interventions that relieve severe AS, but normality is often not immediately achievable and probably requires continued adaptation. Finally, the physiological assessment of coronary artery disease in patients with AS represents an ongoing challenge, as the invasive physiological measures used in current cardiology practice are yet to be validated in this population. This Review discusses the key concepts of coronary pathophysiology in patients with AS through presentation of contemporary basic science and data from animal and human studies.

Management of Patients With Aortic Valve Stenosis

With increased life expectancy and aging of the population, aortic stenosis is now one of the most common valvular heart diseases. Early recognition and management of aortic stenosis are of paramount importance because untreated symptomatic severe disease is universally fatal. The advent of transcather aortic valve replacement technologies provides exciting avenues of care to patients with this disease in whom traditional surgical procedures could not be performed or were associated with high risk. This review for clinicians offers an overview of aortic stenosis and updated information on the current status of various treatment strategies. An electronic literature search of PubMed, MEDLINE, EMBASE, and Scopus was performed from conception July 1, 2016, through November 30, 2017, using the terms aortic stenosis, aortic valve replacement, transcatheter aortic valve replacement (TAVR), transcatheter aortic valve insertion (TAVI), surgical aortic valve replacement, aortic stenosis flow-gradient patterns, low-flow aortic valve stenosis, natural history, stress testing, pathophysiology, bicuspid aortic valve, and congenital aortic valve disease.

Prosthesis-patient mismatch - what cardiac anesthesiologists need to know?

Prosthesis-patient Mismatch (PPM) is not uncommon with an incidence reported up to 70% after aortic valve (AV) replacement. Severe forms of PPM are less common (up to 20%); PPM can lead to increased short- and long-term morbidity and mortality. It is important to discriminate PPM from other forms of prosthetic valve dysfunction. Sometimes, prosthetic valve degenerative disease may coexist with PPM. Echocardiography plays an important role in the prevention and diagnosis of PPM. Preemptive strategies to prevent PPM include insertion of newer generation prosthetic valves with better hemodynamic characteristics, stentless prosthesis, aortic root enlargement to insert a larger prosthesis, aortic homograft, and transcutaneous AV implantation. We present an illustrative case and review the literature on PPM pertinent to anesthesiologists.

Drug Therapy for Heart Valve Diseases

Valvular heart diseases (VHDs) are progressive. When not caused by acute comorbidities they are generally characterized by long asymptomatic phases during which hemodynamic severity may progress leading to morbidity and mortality. Treatment depends on VHD type and severity but when severe and symptomatic, usually involves mechanical intervention. Asymptomatic patients, and those who lack objective descriptors associated with high risk, are closely observed clinically with optimization of associated cardiovascular risk factors until surgical indications develop. Though often prescribed based on theory, no rigorous evidence supports pharmacological therapy in most chronic situations though drugs may be appropriate in acute valvular diseases, or as a bridge to surgery in severely decompensated patients. Herein, we examine evidence supporting drug use for chronic VHDs.

Regression of left ventricular mass after implantation of the sutureless 3f Enable aortic bioprosthesis

Left ventricular hypertrophy in aortic stenosis is considered a compensatory response for the maintenance of systolic function but a risk factor for cardiac morbidity and death. We investigated the degree of left ventricular mass regression after implantation of the sutureless Medtronic 3f Enable Aortic Bioprosthesis. We studied 19 patients who, from May 2010 through July 2011, underwent isolated aortic valve replacement with the 3f Enable bioprosthetic valve, with clinical and echocardiographic follow-up at 6 months. The mean age was 77.1 ± 5.1 years (range, 68-86 yr); 14 patients were women (73.7%); and the mean logistic EuroSCORE was 15.4% ± 11.8%. Echocardiography was performed preoperatively, at discharge, and at 6 months' follow-up. The left ventricular mass was calculated by means of the Devereux formula and indexed to body surface area. The left ventricular mass index decreased from 146.1 ± 47.6 g/m(2) at baseline to 118.1 ± 39.8 g/m(2) at follow-up (P=0.003). The left ventricular ejection fraction did not change significantly. The mean transaortic gradient decreased from 57.3 ± 14.2 mmHg at baseline to 12.3 ± 4.6 mmHg at discharge and 12.2 ± 5.3 mmHg at follow-up (P <0.001), and these decreases were accompanied by substantial clinical improvement. No moderate or severe paravalvular leakage was present at discharge or at follow-up. In isolated aortic stenosis, aortic valve replacement with the 3f Enable bioprosthesis results in significant regression of left ventricular mass at 6 months' follow-up. However, this regression needs to be verified by long-term echocardiographic follow-up.

Left ventricular mass regression after two alternative sutureless aortic bioprostheses

OBJECTIVE

Left ventricular (LV) hypertrophy in aortic stenosis (AS) constitutes a risk factor for cardiac morbidity and mortality. The aim of this study was to investigate the degree of LV mass regression after aortic valve replacement (AVR) with two alternative sutureless self-expanding strategies: Perceval S (Sorin Group, Saluggia, Italy) (P) and 3f Enable (Medtronic, ATS Medical, Minneapolis, MN USA) (E) aortic bioprostheses.

METHODS

Between March 2010 and December 2011, 129 patients with symptomatic AS underwent AVR with the Perceval S or 3f Enable bioprostheses in two cardiac surgery departments (Massa, Italy; Nuremberg, Germany). We analyzed 45 patients in group P and 19 in group E undergoing isolated AVR with a 6-month follow-up. The LV mass was calculated using the Devereux formula and was indexed to body surface area.

RESULTS

Baseline patient characteristics showed no significant differences between the two groups. There were no in-hospital deaths. Two patients in group P died at follow-up versus zero in group E (P = 0.49). Mean LV mass index decreased from 146.6 (78) g/m at baseline to 123.3 (63) g/m at follow-up (P < 0.001) in group P and from 146.1 (47.6) g/m to 118.1 (39.8) g/m (P = 0.003) in group E, with no significant difference between the two groups (P = 0.315). This effect was accompanied by significant clinical improvement.

CONCLUSIONS

In isolated AS, AVR with sutureless bioprostheses is associated with a significant regression in LV mass at 6-month follow-up. No significant differences were present between the two alternative sutureless strategies. However, regression needs an evaluation with long-term echocardiographic examinations.

[Asymptomatic severe aortic stenosis: a reopened debate]

Aortic stenosis is a complex disease. About 2-7% of the population over 65 years of age is affected by its degenerative form. In patients with severe aortic stenosis presenting with symptoms or left ventricle ejection fraction (LVEF)<.50, aortic valve replacement is indicated. Management and timing of surgery in asymptomatic patients with preserved LVEF is still a matter of debate. Recent published data show that about one third of these patients present with low left ventricle stroke volume, which may affect survival. For this reason, and considering that aortic valve replacement is in most cases a low risk procedure, early surgery in this subgroup is a strategy that deserves to be taken into account. In this review we report on these recent findings, which allow understanding why patients with asymptomatic severe aortic stenosis should not be considered and treated as a homogenous population.

Left ventricular mass regression after sutureless implantation of the Perceval S aortic valve bioprosthesis: preliminary results

OBJECTIVES

Left ventricular (LV) hypertrophy in aortic stenosis (AS) is considered a compensatory response helping maintain systolic function, but constitutes a risk factor for cardiac morbidity and mortality. The aim of this study was to assess the degree of LV mass regression after sutureless implantation of the Perceval S aortic valve bioprosthesis (Sorin Group, Saluggia, Italy).

METHODS

Between March 2010 and July 2012, 78 patients with symptomatic AS underwent isolated aortic valve replacement (AVR) with the Perceval bioprosthesis. Mean age was 77.1 ± 5.3 years, 46 patients were female (59%) and mean logistic EuroSCORE was 11 ± 7.5%. Echocardiography was performed preoperatively, at discharge, and at follow-up (mean 13.5 ± 7.3 months). LV mass was calculated using the Devereux formula and indexed to body surface area.

RESULTS

There was 1 in-hospital non-cardiac death and 3 late deaths. LV mass index decreased from 148.4 ± 46 g/m(2) at baseline to 119.7 ± 38.5 g/m(2) at follow-up (P = 0.002). No significant changes were observed in LV hypertrophy and/or relative wall thickness >0.42 as well as in LV ejection fraction. Mean aortic gradient decreased from 49.5 ± 15.8 mmHg at baseline to 11.6 ± 5.1 mmHg at discharge and 8.3 ± 4.4 mmHg at follow-up (P < 0.001), resulting in significant clinical improvement. No moderate or severe paravalvular leakage was observed at discharge and at follow-up.

CONCLUSIONS

In AS patients, isolated AVR with the Perceval sutureless bioprosthesis is associated with significant LV mass regression at 1-year follow-up. However, longer-term follow-up is necessary to confirm these findings.

Calcific Aortic Stenosis: Pathology and Role of Balloon Aortic Valvuloplasty

Calcific aortic stenosis (AS) is a common expression of aortic valve disease and increases in prevalence with advancing age. Recent studies have shown that calcific deposition in aortic valve leaflets is an actively regulated process with many pathophysiologic similarities to atherosclerosis. Surgical valve replacement is the definitive treatment of calcific AS, but many patients do not undergo surgery because of prohibitive comorbidities or other high-risk features. Balloon aortic valvuloplasty remains an option for temporary palliation and symptomatic relief, and continues to serve as a bridge to aortic valve replacement in certain patients with AS requiring temporary hemodynamic stabilization.

Long-term predictors of mortality and functional recovery after aortic valve replacement for severe aortic stenosis with left ventricular dysfunction

INTRODUCTION AND OBJECTIVES

At present, surgery is the only recommended effective treatment for severe aortic stenosis. However, the surgical risk is increased when left ventricular dysfunction is present. The aim of this study was to identify predictors of postoperative and long-term mortality and functional improvement after valve replacement in patients with severe aortic stenosis and left ventricular dysfunction.

METHODS

Between 1996 and 2008, 635 consecutive patients with severe aortic stenosis underwent surgery. Early postoperative mortality in the 82 with an ejection fraction <40% was 19.5%. The following independent predictors of early postoperative mortality were identified: female sex (odds ratio [OR]=2.60; 95% confidence interval [CI], 2.20-89.0; P=.004), mild mitral regurgitation (OR=2.38; 95% CI, 1.40-80.0; P=.020) and coronary artery disease (OR=2.09; 95% CI, 1.26-51.0; P=.027).

RESULTS

During the mean follow-up period of 42.59+/-40.83 months, overall mortality was 18.8% and cardiovascular mortality was 11.3%. The only factor associated with increased mortality during follow-up was a low postoperative cardiac output (OR=4.40; 95% CI, 1.20-15.5; P=.02). In total, 70.5% showed early improvement in ventricular function, the predictors of which were: no improvement following a previous myocardial infarction (P=.04), no revascularized coronary lesions (P=.04), and a low aortic valve pressure gradient (P=.02). Functional class improved significantly during follow-up in 93.4% of patients.

CONCLUSIONS

Despite considerable early postoperative mortality in patients with aortic stenosis and left ventricular dysfunction, over the long term there was evidence of better survival coupled to improved ventricular function and functional class.

Impact of Coronary Disease after Aortic Valve Replacement

Left ventricular dimensions tend to reduce after aortic valve replacement in patients with aortic stenosis. Whether concomitant coronary artery disease has an influence on postoperative ventricular dimensions has not been evaluated. Between 1998 and 2002, 112 patients underwent aortic valve replacement for aortic stenosis; 68 had isolated aortic valve replacement, and 44 had combined coronary artery bypass grafting. Left ventricular dimensions were assessed by echocardiography preoperatively and at 3 and 12 months postoperatively. Transvalvular mean gradient, left ventricular end-diastolic diameter, and left ventricular mass index decreased significantly postoperatively, while left ventricular ejection fraction improved. Preoperative left ventricular dimensions in patients with isolated aortic stenosis were worse than in those with aortic stenosis and coronary artery disease. After aortic valve replacement with coronary artery bypass, left ventricular mass index regression was less than that after valve replacement alone, and there was no improvement in ejection fraction. This suggests that coronary artery disease has a negative impact on postoperative myocardial recovery.

Left ventricular response to isometric exercise in aortic valve diseases and its value in the optimal timing of aortic valve replacement

In order to evaluate the left ventricular response to isometric exercise in different types of aortic valve disease, isometric exercise tests were performed during cardiac catheterization in 14 patients with pure aortic stenosis, 20 with combined aortic stenosis and regurgitation, and 18 with pure aortic regurgitation. Patients with angina pectoris in whom coronary angiography had not been performed were excluded. Thirty-seven patients were recatheterized 12 months after aortic valve replacement, and the ventricular response to exercise was re-evaluated. Preoperatively, the ejection fraction did not change significantly during exercise in patients with aortic stenosis, tended to decrease in patients with combined valve lesion, and decreased significantly in patients with aortic regurgitation (p less than 0.001). In the three patients whose ejection fraction during preoperative exercise decreased to below 0.40, it remained below 0.50 after successful aortic valve replacement. It appears possible to reveal left ventricular dysfunction in many patients with aortic regurgitation and in some with combined aortic valve disease by means of isometric exercise. The severely depressed ventricular dysfunction during exercise does not appear to correct totally after surgery.

Severe aortic insufficiency and normal systolic function: determining regional left ventricular wall stress by finite-element analysis

BACKGROUND

Because severe aortic insufficiency in the setting of preserved left ventricular function is often associated with a long asymptomatic period and unpredictable course on medical therapy, sensitive indices of left ventricular systolic performance are necessary for the optimal direction of therapeutic intervention. Because myocardial wall stress is closely related to both pathologic cardiac remodeling and ultimately to left ventricular decompensation, an accurate description of regional wall stress distribution may improve our ability to clinically manage these patients appropriately. The objectives of this study were (1) to define sensitive, noninvasive indices of left ventricular systolic performance to assist the clinician in the serial evaluation and early detection of increased left ventricular wall stress and, therefore, inadequate left ventricular remodeling and subsequent myocardial decompensation of patients with aortic insufficiency, and (2) to quantify differences in instantaneous global and regional end-systolic wall stress between normal subjects and patients.

METHODS

Magnetic resonance imaging was performed on 23 normal volunteers and 19 patients with aortic insufficiency and normal systolic function (ejection fraction, 57% +/- 6%). Finite-element analysis was used to estimate global and regional end-systolic stress.

RESULTS

End-systolic stress was significantly higher in the patient group globally (154,700 +/- 31,711 versus 96,781 +/- 23,185 dyne/cm(2); p < 0.001) and regionally (p < 0.001 in all segments) despite normal systolic function and similar end-systolic pressures.

CONCLUSIONS

End-systolic stress as determined by magnetic resonance imaging and finite-element analysis may have considerable potential as a noninvasive, clinically applicable index of regional left ventricular function that may help in the serial evaluation, optimal management, and early identification of left ventricular decompensation in patients with aortic insufficiency.

Survival after aortic valve replacement for severe aortic stenosis with low transvalvular gradients and severe left ventricular dysfunction

OBJECTIVE

We sought to assess whether aortic valve replacement (AVR) among patients with severe aortic stenosis (AS), severe left ventricular (LV) dysfunction and a low transvalvular gradient (TVG) is associated with improved survival.

BACKGROUND

The optimal management of patients with severe AS with severe LV dysfunction and a low TVG remains controversial.

METHODS

Between 1990 and 1998, we evaluated 68 patients who underwent AVR at our institution (AVR group) and 89 patients who did not undergo AVR (control group), with an aortic valve area < or = 0.75 cm(2), LV ejection fraction < or = 35% and mean gradient < or = 30 mm Hg. Using propensity analysis, survival was compared between a cohort of 39 patients in the AVR group and 56 patients in the control group.

RESULTS

Despite well-matched baseline characteristics among propensity-matched patients, the one- and four-year survival rates were markedly improved in patients in the AVR group (82% and 78%), as compared with patients in the control group (41% and 15%; p < 0.0001). By multivariable analysis, the main predictor of improved survival was AVR (adjusted risk ratio 0.19, 95% confidence interval 0.09 to 0.39; p < 0.0001). The only other predictors of mortality were age and the serum creatinine level.

CONCLUSIONS

Among select patients with severe AS, severe LV dysfunction and a low TVG, AVR was associated with significantly improved survival.

Clinical significance of iodine-123-15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid myocardial scintigraphy in patients with aortic valve disease

The present study sought to determine whether myocardial fatty acid metabolism as assessed with iodine-123-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) scintigraphy is impaired in patients with aortic valve disease (AVD) and whether the degree of the metabolic abnormality reflects the severity of AVD. BMIPP scintigraphy was performed in 12 patients with aortic stenosis (AS), 14 patients with aortic regurgitation (AR), and 9 healthy volunteers, and from that the heart-mediastinum uptake ratio (H/M ratio) corrected by the left ventricular (LV) mass (U/Mass ratio) and the myocardial washout rate (WR) were obtained. The H/M ratio tended to be higher in patients than in healthy volunteers (3.3 +/- 0.7 for AS, 3.5 +/- 0.5 for AR, 3.0 +/- 0.3 for healthy volunteers), and the WR was significantly higher in patients than in healthy volunteers (42.8 +/- 9.1% for AS, 35.7 +/- 6.5% for AR, 19.6 +/- 9.1% for healthy volunteers, p<0.01). In the AS patients, the U/Mass ratio showed significant negative correlations (r=-0.79 to -0.90, all p<0.01) and the WR showed significant positive correlations (r=0.61 to 0.82, all p<0.01) with transaortic pressure gradient, LV wall thickness, and LV mass. Similarly, in AR patients these BMIPP parameters showed proportional changes to the LV volumes and LV mass (r=-0.79 to -0.83, all p<0.01 for U/Mass ratio, r=0.55 to 0.70, p<0.05 to <0.01 for WR). In the 9 patients who underwent aortic valve replacement, the BMIPP parameters tended to normalize with increasing U/Mass ratio (0.90 +/- 0.41 x 10(-2)/g to 1.34 +/- 0.59 x 10(-2)/g, p<0.05) and decreasing WR (41.9 +/- 8.8% to 35.4 +/- 9.2%, p<0.01) after surgery. Myocardial fatty acid metabolism as assessed with BMIPP scintigraphy was impaired in patients with aortic valve disease and the U/Mass ratio and WR reflect the severity. These parameters may be useful for the noninvasive assessment of the myocardial metabolic abnormalities caused by hemodynamic overload.

Time course of left ventricular remodeling after stentless aortic valve replacement

BACKGROUND

Stentless aortic valves are associated with a significant decrease in left ventricular hypertrophy. This study examined the time course and factors affecting left ventricular mass regression (LVMR) after aortic valve replacement (AVR) with Cryolife O'Brien (CLOB) (Cryolife International, Atlanta, Ga) stentless valves.

METHODS

Between 1993 and 2000, 130 consecutive patients underwent AVR with CLOB. Mean age was 71.3 +/- 6.3 years. Sixty-four (49.2%) were male. Mean body surface area (BSA) was 1.7 +/- 0.2 m(2). Mean valve size implanted was 23.6 +/- 2.0 mm. All patients were monitored with serial echocardiograms; the first study was performed preoperatively, and subsequent controls were at 6 months, 1, 2, 3, 4, 5, 6, and 7 years, respectively. Left ventricular mass was calculated by the Devereux formula and indexed by BSA.

RESULTS

Analysis of variance showed a significant reduction in the left ventricular mass index (LVMI) over time (P < .001). Most LVMRs occurred within the first 6 months, and after 1 year LVMI had decreased by 37.5% with further, but not statistically significant, reductions at later examinations. We found that baseline BSA > 1.75 m(2), male sex, arterial blood pressure > or = 150 mm Hg, left ventricular ejection fraction < or = 35%, New York Heart Association functional class > or = III, non-sinus rhythm, and prevalent aortic incompetence to be factors influencing LVMR. LVMR was not related to postoperative effective orifice area < or = 0.85 cm/m(2) and prosthetic size.

CONCLUSIONS

AVR with a CLOB valve is followed by a significant LVMR that occurs soon after surgery. It is influenced by several patient-related factors: most of them can be predicted preoperatively.

Differences in left ventricular response between rheumatic and myxomatous mitral valve disease following mitral valve replacement

OBJECTIVE

We studied whether differences exist between hearts having rheumatic mitral valves and those having myxomatous mitral valves, in functional, geometrical, and mass changes in the left ventricle after mitral valve replacement.

METHODS

Patients who underwent mitral valve replacement without preservation of annular-papillary continuity for pure mitral incompetence were classified into rheumatic and myxomatous based on valvular histopathology. Echographic data measured before surgery was compared to that about 3 weeks after surgery.

RESULTS

In the rheumatic group, ejection fraction decreased from 57.5 +/- 10.8 to 47.7 +/- 12.0, indexed left ventricular internal dimension in systole (mm/m2) from 24.7 +/- 6.8 to 20.7 +/- 6.2 (P = 0.0001), and left ventricular mass index (g/m2) from 205 +/- 55 to 138 +/- 54 (P = 0.0002). In the myxomatous group, ejection fraction decreased from 60.4 +/- 11.6 to 39.7 +/- 14.5 (P = 0.0001), indexed left ventricular internal dimension in systole from 24.2 +/- 5.6 to 23.1 +/- 5.5, and left ventricular mass index from 195 +/- 83 to 111 +/- 72 (P = 0.0004). Mean wall thickness index and relative wall thickness showed significant differences between the two groups postoperatively but no significant difference preoperatively.

CONCLUSION

Hearts dilated due to chronic mitral incompetence respond differently after valvular replacement with total chordal excision depending on whether a rheumatic or myxomatous mitral valve is involved.

Coronary flow reserve improves after aortic valve replacement for aortic stenosis: an adenosine transthoracic echocardiography study

OBJECTIVES

The goal of this study was to assess coronary flow reserve (CFR) before and after aortic valve replacement (AVR).

BACKGROUND

Coronary flow reserve is impaired under conditions of left ventricular (LV) hypertrophy. It is not known whether CFR improves with regression of LV hypertrophy in humans.

METHODS

We investigated 35 patients with pure aortic stenosis, LV hypertrophy and normal coronary arteriograms. Patients underwent adenosine transthoracic echocardiography on two occasions--immediately before AVR and six months postoperatively. Left ventricular mass, distal left anterior descending coronary artery (LAD) diameter, flow and CFR were assessed on each occasion.

RESULTS

Distal LAD diameter was successfully imaged in 30 patients (86%), and blood flow was successfully imaged in 27 (77%). Paired data were subsequently available in 24 patients, of whom 14 were men, mean age 68.1+/-12.5 years, body mass index 24.5+/-2.0 kg/m2, aortic valve gradient 93+/-32 mm Hg. Pre- to post-AVR a significant decrease was seen in LV mass (271+/-38 vs. 236+/-32g, p<0.01) and LV mass index (154+/-21 vs. 134+/-21 g/m2, p< 0.01). Distal LAD diameter fell from 2.27+/-0.37 to 2.23+/-0.35 mm, p = 0.08). Pre- to post-AVR there was no significant change in resting parameters of peak diastolic velocity (0.43+/-0.16 vs. 0.41+/-0.11 m/s), distal LAD flow 23.3+/-10.1 vs. 20.9+/-5.2 ml/min or distal LAD flow scaled for LV mass (8.7+/-3.8 vs. 9.0+/-2.5 ml/min/100 g LV mass), but there was significant increase in hyperemic peak diastolic velocity (0.71+/-0.26 vs. 1.08+/-0.24 m/s; p<0.01), distal LAD flow (37.8+/-11.3 vs. 53.5+/-16.1 ml/min; p<0.01) and distal LAD flow scaled for LV mass (14.3+/-5.0 vs. 23.3+/-8.5 ml/min/100 g LV mass; p<0.01). Coronary flow reserve, therefore, increased from 1.76+/-0.5 to 2.61+/-0.7.

CONCLUSIONS

Coronary flow reserve increases after AVR for aortic stenosis. This increase occurs in tandem with regression of LV hypertrophy.

Pulmonary autograft replacement of the bicuspid aortic valve: a successful surgical option for young adults

A severely dysfunctioning congenitally bicuspid aortic valve may require surgical treatment within the fourth decade of life. Among conventional options, the pulmonary autograft (PA) offers many theoretical advantages particularly for young patients, including potential for growth, hemodynamic performance, no need for anticoagulants and freedom from endocarditis. However the operation is more complex and longer, may interfere with coronary and right ventricular anatomy and function and may expose the patient to the downside of two valves at risk. Aim of this retrospective study was to evaluate the mid-term results achieved with the PA performed in adolescents and young adults with a bicuspid aortic valve. Between July 94 and June 98, 26 patients, 22 males and four females, with a mean age of 24+/-10 years (range, 11 to 38), underwent bicuspid aortic valve replacement with a pulmonary autograft (stenosis 2-8%; insufficiency 13-50%; combined 11-42%). Eight patients (31%) were in NYHA FC I, 17 (65%) in II, and 1 (4%) in III. Mean preoperative ejection fraction was 67+/-7%. Three patients (11.5%) had a past medical history of endocarditis (healed in all) and in two the PA was a re-do procedure. The PA was inserted as a subcoronary implant in one case (4%) and utilized as a root in the remaining 25 (96%). The right ventricular outflow tract was reconstructed with a cryopreserved pulmonary homograft conduit in all cases. Mean cardiopulmonary bypass and aortic crossclamp times were 204+/-50 min (range, 174 to 300) and 157+/-35 min (range, 133 to 193) respectively. No early or late deaths had occurred at a mean follow-up of 22.5 months (range, 5 to 47.5). The first patient in the series (4%) was reexplored for bleeding and needed transfusions. The subsequent routine use medical and surgical strategies resulted in no further need for postoperative reexploration, and successful containment of total postoperative blood loss (<350 ml/m2BSA). 2-D Echo evaluation of neo-aortic valve competence at 6 months, revealed no evidence of aortic valve regurgitation in 17 (65%), trivial regurgitation in seven (27%), mild in one (4%) and mild-to-moderate in one (4%). The latter patient (subcoronary implant PA) required reoperation. At six months, the mean degree of regression of left ventricular mass compared to pre-operative data, was 36% (333+/-94 to 212+/-60 gr, p<0.05). All patients are asymptomatic, in NYHA FC I, and enjoy normal social interaction. In conclusion, PA root implantation can be offered as a low-risk alternative to conventional prosthetic aortic valve replacement to adolescents and young adults with a bicuspid aortic valve. The routine achievement of blood loss containment has minimized the risk of transfusion thus contributing to expand the indication in young patients. Continued patients evaluation particularly with regard to evidence of neo-aortic valve degeneration, root dilatation and homograft dysfunction in the long term is warranted.

Regression of ventricular repolarisation inhomogeneity after aortic bileaflet valve replacement in patients with aortic stenosis

BACKGROUND

Aortic valve replacement relieves mechanical outflow obstruction in patients with aortic stenosis. However, there is limited information on whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity.

OBJECTIVES

To determine whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity in patients with aortic stenosis after bileaflet aortic valve replacement.

METHODS

We studied the changes of electrocardiographic QT or QTc intervals and QT or QTc dispersions of 71 patients with severe aortic stenosis and angiographically insignificant coronary lesions (<50% in diameter) before and after valve replacement (6+/-3 days after operation). Seventy-one healthy control subjects, matched for age and sex, served as control subjects. Twelve-lead electrocardiograms and echocardiographic examinations were measured before and after surgery. The QT interval was corrected for heart rate using the standard Bazett formula. QT dispersion was defined as the difference between maximal and minimal QT interval measurements occurring among any of the 12 leads on a standard electrocardiogram. QTc dispersion was calculated in a manner similar to QT dispersion. No subject had fewer than nine measurable leads.

RESULTS

Left ventricular systolic blood pressure, pressure gradient across aortic valve, left ventricular mass index, and systolic wall stress were significantly reduced after valve replacement compared with before valve replacement. The QT interval significantly decreased from 425+/-38 ms to 398+/-32 ms after replacement (P<0.0001). The QTc dispersion significantly decreased from 62+/-25 ms to 32+/-13 ms after replacement (P<0.0001). The value of QT or QTc dispersion after replacement was similar to that in controls. Univariate analysis revealed that QTc dispersion was significantly only correlated with left ventricular mass index (r=0.236, P=0.05). Multivariate analysis revealed that the best predictor of QTc dispersion was sex and left ventricular mass index (P=0.008 and 0.005, respectively).

CONCLUSIONS

Our study demonstrated a favorable consequence of aortic valve replacement distinct from hemodynamic improvement. Patients with aortic stenosis before valve replacement have abnormal prolonged QT or QTc intervals and increased QT or QTc dispersions. After successful valve replacement left ventricular mass index regressed and QT or QTc intervals and QT or QTc dispersions were normalized. These findings warrant further investigation in a large trial and long-term follow-up for clinical implications.

Aortic stenosis. Clinical evaluation and optimal timing of surgery

Aortic valve disease is common in the elderly with recent data suggesting that aortic sclerosis and stenosis are the end-stage of an active disease process. Aortic atenosis may be diagnosed at symptom onset (angina, heart failure or syncope) but often the diagnosis is suspected in an asymptomatic patient with a systolic murmur. The diagnosis can be confirmed and disease severity evaluated reliably using Doppler echocardiography. Symptomatic severe aortic stenosis is treated with valve replacement, even in the elderly, due to the extremely poor prognosis without relief of outflow obstruction. Management is controversial when there is coexisting moderate aortic stenosis and left ventricular systolic dysfunction.

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.

Two-dimensional echocardiographic assessment of the progression of aortic root size in 127 patients with chronic aortic regurgitation: role of the supraaortic ridge and relation to the progression of the lesion

Although aortic root dilation has etiologic and prognostic significance in patients with chronic aortic regurgitation (AR), no information is available regarding changes over time in aortic root size in patients with the entire spectrum of AR severity or how such changes relate to progression of the AR or to left ventricular (LV) overload. To analyze this, a total of 127 patients with chronic AR who had more than 6 months of follow-up by two-dimensional and Doppler echocardiography were included in the study (69 men and 58 women; mean age 59.3 +/- 21.2 years [range 14 to 94 years]; 67 cases of mild, 45 moderate, 15 severe, and 21 bicuspid aortic valve disease). The aortic anulus, sinuses of Valsalva, supraaortic ridge, and ascending aorta were measured in the parasternal long-axis view, LV volumes were calculated (biplane Simpson's approach), and the severity of AR was quantified based on proximal jet size and graded according to an algorithm that takes into account major color Doppler criteria. At entry to the study, significant differences between patients with mild, moderate, and severe AR were noted only in supraaortic ridge size (1.46 +/- 0.29 cm/m2 vs 1.63 +/- 0.33 cm/m2 [p < 0.006]; vs 1.67 +/- 0.43 cm/m2 [p < 0.03]). A significant increase in aortic root size at all levels was observed during the follow-up period in all three groups of severity of AR. The rate of change of the supraaortic ridge, the upper support structure of the anulus and cusps, was faster in patients with more severe degrees of AR (p = 0.013); this was not the case at the other aortic levels. No differences were observed in aortic root size or rate of progression between patients with bicuspid or tricuspid aortic valves. Patients were considered "progressive" if they lay on the steepest positive segment of the curve representing the rank order in the rate of aortic root progression. Compared with "nonprogressive" patients, patients who were progressive in supraaortic ridge size (rate >0.12 cm/yr; n = 23) had a faster rate of progression in the degree of regurgitation as assessed by the regurgitant jet area/LV outflow tract area ratio measured in the parasternal short-axis view (0.48 +/- 0.45 vs 0.24 +/- 0.5/yr; p < 0.03) and a foster rate of progression of LV end-diastolic volume (30 +/- 22.8 vs 14.4 +/- 15.6 ml/yr; p < 0.0002) and LV mass (70.8 +/- 74.4 vs 16.8 +/- 19.2 gm/yr; p < 0.0004). In conclusion, there is progressive dilation of the aortic root at all levels, even in patients with mild AR. More rapid progression in aortic root size is associated with more rapid progression of the underlying aortic insufficiency, as well as more rapid increases in LV volume and mass.

Hemodynamic performance of the St. Jude Medical Hemodynamic Plus valve

The hemodynamic performance of the St. Jude Medical Hemodynamic Plus valve (HP) for a small aortic annulus was compared to that of the standard St. Jude Medical valve (SJM). Doppler echocardiographic parameters were evaluated in patients undergoing aortic valve replacement with either a 19 mm HP (HP19, n = 7), a 21 mm HP (HP21, n = 8), a 19 mm SJM (SJM19, n = 16), or a 21 mm SJM (SJM21, n = 34). The peak and mean pressure gradients and peak flow velocity were significantly (p < 0.05) lower in both patients with the HP21 and those with the HP19 than patients with the SJM21 and those with the SJM19, respectively. The echocardiographic parameters of the patients with the HP19 corresponded closely to those of patients with the SJM21. The left ventricular mass index regressed markedly in patients with the HP19 during the late postoperative period. The results suggested that the hemodynamic performances of certain sizes of the HP were superior to those of the same size SJMs and were considered to be equivalent to those of the next size larger SJM.

Left ventricular mass regression early after aortic valve replacement

BACKGROUND

Regression of left ventricular hypertrophy is an important and well-recognized salutary effect of aortic valve replacement. The earliest evidence of left ventricular mass regression after aortic valve replacement and the influence of prosthesis type are not well known, and were the focus of this study.

METHODS

Transthoracic echocardiography was used to measure left ventricular mass index preoperatively and before discharge in 57 consecutive patients undergoing isolated aortic valve replacement (with or without coronary artery bypass grafting).

RESULTS

Three patients were excluded from the study because of inability to obtain accurate M-mode echocardiographic images for left ventricular mass measurement preoperatively (1) or postoperatively (2). Of the remaining 54 patients, mechanical bileaflet valves were used in 19, stented tissue bioprostheses were implanted in 15, and a stentless porcine bioprosthesis was chosen for 20. Postoperative echocardiograms were obtained 4.9 +/- 2.3 days after aortic valve replacement (range, 2 to 9 days). A two-way repeated-measures analysis of variance demonstrated a significant reduction of left ventricular mass index before discharge (preoperative 141.4 +/- 45.2 g/m2, postoperative 127.5 +/- 32.8 g/m2; p = 0.0005) but no differences between prostheses.

CONCLUSIONS

Left ventricular mass regression begins early after aortic valve replacement, probably because of reduction of transvalvular gradients and left ventricular wall stress. At least in the very early postoperative period, the type of prosthesis does not influence the extent of mass regression.

Effects of valve substitute on changes in left ventricular function and hypertrophy after aortic valve replacement

BACKGROUND

Residual left ventricular hypertrophy adversely affects long-term outcome after aortic valve replacement. A stentless biological valve in the aortic position has been shown to offer a better hemodynamic profile than a stented one. However, it remains to be defined whether this difference is translated into inter-mediate-term effects on left ventricular structure and function.

METHODS

One hundred thirty-seven patients receiving single aortic valve replacement (52 with concomitant coronary artery bypass graft) were enrolled in this study. Ninety-eight were men, and the mean age was 68 years (range, 55 to 90 years). Of the 137 patients, 39 had an aortic homograft, 72 a Toronto stentless porcine valve, and 26 had a stented porcine or bileaflet mechanical valve, with mean valve size of 25 +/- 2.5 mm (mean +/- standard deviation). Left ventricular muscle mass and function were assessed by M-mode echocardiography performed before and 0.5, 6, 12, 24, and 36 months after operation, and recorded on paper for off-line digitizing. Peak valve prosthesis pressure gradients were quantified by continuous wave Doppler.

RESULTS

A total of 330 echocardiograms obtained during this study were adequate for computer digitizing. Clinical data, preoperative left ventricular function, and hypertrophy were similar between the three groups. Significant improvement in left ventricular function and major regression of left ventricular hypertrophy had occurred in the entire population by 6 months after operation. Multivariate analysis of variance showed that patients with previous aortic regurgitation had a larger left ventricular cavity size (p < 0.001) and greater mass index (p = 0.001) postoperatively than those with previous aortic stenosis. In addition, peak valvular gradient was lower (p < 0.001), mass index less (p < 0.001), and left ventricular function more normal both systolic, by a greater peak velocity of dimension shortening (p = 0.05) and wall thickening (p = 0.002), and diastolic, by a greater peak velocity of dimension lengthening (p = 0.046), with an aortic homograft or stentless porcine valve compared with a mechanical or stented biological valve. There was no significant difference in peak valve gradient, left ventricular mass index, or function between the aortic homograft and the stentless porcine valve. Age, sex, and concomitant coronary artery bypass graft, as well as aortic cross-clamp time, cardioplegia method, and valve size all proved to be insignificant determinants of postoperative left ventricular hypertrophy or function.

CONCLUSIONS

In the first 2 years after implantation, the superior hemodynamic performance of aortic homograft and stentless porcine valve appears to result in more extensive regression of ventricular hypertrophy and greater improvement of left ventricular function than occurs with a mechanical or stented biological valve. These findings encourage the use of a stentless biological valve in older patients requiring aortic valve replacement, and a larger scale long-term randomized study of stentless versus stented biological valve or mechanical valve seems warranted.

Influence of the size of aortic valve prostheses on hemodynamics and change in left ventricular mass: implications for the surgical management of aortic stenosis

Discussion of aortic valve replacement has primarily concerned the choice between tissue and mechanical prostheses. Less emphasis has been placed on prosthesis size. Despite technical advances increasing prosthesis orifice area, small valves implanted in the unenlarged aortic root may not be significantly less obstructive than the stenotic native valves they replace.

METHODS

In this work we studied 52 patients (31 women, 21 men; mean age 59.2 years) in whom valve prostheses sized 19, 21, 23, or 25 mm (30 bioprostheses and 22 tilting disc valves) had been implanted to replace stenotic aortic valves. Most patients with 19 or 21 mm prostheses were women. Doppler and conventional echocardiographic studies were performed in the 10 days preceding the operation and between 10 and 40 months (mean 18 months) after the operation. The patients receiving larger valve sizes had significantly larger body surface areas than those receiving smaller valve sizes (mainly women).

RESULTS

No significant differences were observed between preoperative and postoperative diameters or left ventricular systolic function parameters, but left ventricular mass and mass index decreased in all four groups (albeit nonsignificantly in the 19 mm group, and with less statistical significance in the 21 mm group than in the 23 and 25 mm groups). Postoperative peak and mean transvalvular pressure drops were significantly greater in the 19 mm group than in the other groups, and the 21 mm group had significantly greater transvalvular pressure drops than the 25 mm group. Postoperative effective valve area was significantly smaller in the 19 mm group than in the 21 mm group, and significantly smaller in the 21 mm group than in the 23 and 25 mm groups.

CONCLUSION

We conclude that despite undeniable recent improvements in the design of artificial heart valves, 19 mm aortic prostheses continue to create significant obstruction of the left ventricular outflow tract and, possibly as a consequence of this, fail to bring about significant reduction in left ventricular hypertrophy.

Normalization of left ventricular nonuniformity late after valve replacement for aortic stenosis

The aim of the present study was to evaluate nonuniformity in pressure overload hypertrophy due to aortic stenosis. Twenty patients were included in the present analysis. Ten patients with severe aortic stenosis were studied preoperatively as well as early (21 +/- 8 months) and (89 +/- 21 months) after aortic valve replacement (AVR) using left ventricular biplane angiograms, high-fidelity pressure measurements and endomyocardial biopsies. Ten normal subjects served as controls. LV systolic function was assessed from biplane ejection fraction, and diastolic function from the time constant of relaxation, the peak filling rate and the constant of myocardial stiffness. Nonuniformity was evaluated from the coefficient of variation of the time to end-systole (systolic asynchrony) and peak filling rate (diastolic asynchrony) of 12 regions in right anterior oblique and left anterior oblique projection. Ejection fraction was comparable in patients with aortic stenosis and in controls, whereas preoperatively diastolic dysfunction with prolonged relaxation and increased stiffness was present in patients with aortic stenosis and was normalized late after AVR. LV systolic asynchrony was present (>25D of controls) in 7 and diastolic asynchrony in 10 of 10 patients with aortic stenosis. Early as well as late after AVR systolic asynchrony was normalized in 9 of 10 patients. Diastolic asynchrony was present early AVR in all but one patient, although there was a significant improvement with respect to the preoperative evaluation. Late after AVR there was a normalization of diastolic asynchrony in 9 of 10 patients with aortic stenosis. Thus, it is concluded that systolic asynchrony is normalized early after AVR probably due to its load-sensitivity, whereas diastolic asynchrony persists probably due to residual LV hypertrophy with increased interstitial fibrosis and myocardial stiffness. Late after AVR, diastolic asynchrony is normalized due to structural remodeling with regression of both myocardial hypertrophy and interstitial fibrosis.

Immediate effects of lung transplantation on right ventricular morphology and function in patients with variable degrees of pulmonary hypertension

OBJECTIVES

This study sought to determine the immediate effects of lung transplantation on right ventricular morphology and function in patients with variable degrees of pulmonary hypertension and to evaluate these features as potential markers of immediate outcome.

BACKGROUND

Selected lung transplant recipients with severe preoperative pulmonary hypertension have previously been shown to have a reduction in right ventricular size and improved function at follow-up evaluation.

METHODS

Thirty-two consecutive patients (mean [+/- SD] age 44 +/- 11 years) were prospectively classified into three groups according to their pretransplantation pulmonary artery systolic pressure: severe pulmonary hypertensive group > or = 75 mm Hg, intermediate pulmonary hypertensive group 40 to 74 mm Hg and non-pulmonary hypertensive group < 40 mm Hg. Hemodynamic and transesophageal echocardiographic variables were measured immediately before and after lung transplantation.

RESULTS

Pulmonary artery systolic and mean pressures markedly decreased after transplantation in the severe pulmonary hypertensive group (from 115 +/- 26 to 45 +/- 19 mm Hg and from 76 +/- 14 to 31 +/- 11 mm Hg, respectively, both p < 0.05). Mean pulmonary artery pressure decreased in the intermediate group (from 34 +/- 7 to 26 +/- 7 mm Hg, p < 0.05). Right ventricular end-diastolic area, end-systolic area and eccentricity index decreased in the severe pulmonary hypertensive group after transplantation. End-diastolic area also decreased in the intermediate pulmonary hypertensive group. Right ventricular fractional area change was not significantly different between groups and did not change consistently after transplantation. Three patients with severe pulmonary hypertension who had continued depression of right ventricular function after transplantation died in the immediate postoperative period.

CONCLUSIONS

Lung transplantation is associated with an immediate decrease in pulmonary artery pressures and right ventricular size and normalization of septal geometry but variable changes in right ventricular function. Continued depression of right ventricular fractional area change may be a potential marker of poor outcome.

Left ventricular performance improves late after aortic valve replacement in patients with aortic stenosis and reduced ejection fraction

EF in patients with aortic stenosis and reduced EF who underwent aortic valve replacement did not improve by 1 week postoperatively despite rectification of afterload mismatch. By 6 months, however, EF significantly improved without any further change in ventricular loading conditions. This implies that the benefit from aortic valve replacement (when measured by LV ejection performance) may not be evident until late postoperatively.

Early changes in left ventricular function after aortic valve replacement for isolated aortic stenosis

To assess the immediate effects of aortic valve replacement (AVR) for valvular aortic stenosis (AS) on left ventricular (LV) systolic and diastolic function and global hemodynamics, 17 patients with AS underwent transesophageal echocardiography combined with high-fidelity LV pressure recording and thermodilution cardiac output measurements before cardiopulmonary bypass and 0.5, 6, 12, and 20 hours after AVR. Compared with results before bypass, LV systolic function had already changed 30 minutes after AVR, and remained constant thereafter: peak LV systolic wall stress decreased (from 210 +/- 60 to 130 +/- 40 g.cm-2), peak rate of dimension shortening increased (from 7.3 +/- 2.2 to 9.7 +/- 2.1 cm.s-1), both p < 0.01. Peak segmental external power thus remained constant (16.6 +/- 6.7 vs 17.7 +/- 7.6 mW.cm-3); p = NS. Changes in LV diastolic function and global hemodynamics were delayed. The peak rate of ventricular pressure decrease, normalized to developed end-systolic pressure, increased (from 15 +/- 3.2 to 19 +/- 5.2 s-1) by 6 hours. The minimal ventricular pressure of early diastole decreased (from 8.9 +/- 4.9 to 4.3 +/- 3.7 mm Hg), the peak rate of dimension lengthening of early diastole increased (from 6.0 +/- 3.0 to 8.8 +/- 2.0 cm.s-1), and LV stroke volume index increased (from 24 +/- 7 to 31 +/- 6 ml.m-2) by 12 hours, all p < 0.01. LV incoordination, defined as the dimension changes during isovolumic periods, had also improved significantly at 20 hours. Heart rate and LV enddiastolic dimension did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Recovery of the right ventricle after single-lung transplantation in pulmonary hypertension

Single-lung transplantation has been successfully performed in patients with pulmonary fibrosis and emphysema. In contrast, patients with end-stage pulmonary hypertension (either primary or secondary to Eisenmenger's syndrome) have conventionally been offered heart-lung transplantation. The rationale underlying this approach is that chronic pulmonary hypertension results in irreversible right ventricular dilatation and failure. Recovery of the right ventricle has previously been reported after thromboendarterectomy for chronic large-vessel pulmonary embolism, correction of atrial septal defect or mitral valve replacement. The evolution of right ventricular morphology and function after lung transplantation has not been previously described. This study examines the reversibility of right ventricle dysfunction following normalization of pulmonary artery pressure after single-lung transplantation in 4 patients with pulmonary hypertension. Cardiac function was assessed using electrocardiography, echocardiography and radionuclide angiography. Pulmonary hemodynamic measurements, including pulmonary artery pressure and pulmonary vascular resistance, decreased in all patients after single-lung transplantation. Electrocardiographic changes observed were leftward shift in the QRS axis, and a decrease in P-wave amplitude and in right ventricular force. Echocardiographic examination revealed decreased right atrial, right ventricular and tricuspid valve annular dimensions, normalization of septal motion, and decreased tricuspid regurgitation. Thus, improved pulmonary hemodynamics after single-lung transplantation for pulmonary vascular disease results in reversal of right heart dilatation and dysfunction, and improved myocardial performance. The extent of right ventricular dysfunction beyond which recovery is unlikely to occur has yet to be determined.

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.