Left ventricular myocardial remodeling and contractile state in chronic aortic regurgitation

Assessing Regurgitation Severity, Adverse Remodeling, and Fibrosis with CMR in Aortic Regurgitation

PURPOSE OF REVIEW

Cardiac magnetic resonance (CMR) is emerging as a valuable imaging modality for the assessment of aortic regurgitation (AR). In this review, we discuss the assessment of AR severity, left ventricular (LV) remodeling, and tissue characterization by CMR while highlighting the latest studies and addressing future research needs.

RECENT FINDINGS

Recent studies have further established CMR-based thresholds of AR severity and LV remodeling that are associated with adverse clinical outcomes, and lower than current guideline criteria. In addition, tissue profiling with late gadolinium enhancement (LGE) and extracellular volume (ECV) quantification can reliably assess adverse myocardial tissue remodeling which is also associated with adverse outcomes. The strengths and reproducibility of CMR in evaluating ventricular volumes, tissue characteristics, and regurgitation severity position it as an excellent modality in evaluating and following AR patients. Advanced CMR techniques for the detection of tissue remodeling have shown significant potential and merit further investigation.

Valvular Cardiomyopathy in Aortic Valve Regurgitation Correlates with Myocardial Fibrosis

Objective: At the tissue level, disruption of the extracellular matrix network leads to irreversible cardiac fibrosis, which contributes to myocardial dysfunction. At the myocyte level, downregulation of beta-adrenoceptors (beta-AR) reduces adaptation to increased workload. The aim of our study was to analyse the correlation between myocardial fibrosis and beta-AR sensitivity in patients with aortic valve (AV) disease. Methods: A total of 92 consecutive patients who underwent elective AV surgery between 2017-2019 were included in our study (51 with aortic regurgitation (AR-group); 41 with aortic stenosis (AS-group) and left ventricular (LV) biopsies were obtained intraoperatively. In vitro force contractility testing was performed by measuring beta-AR sensitivity (-log EC₅₀[ISO]). In parallel, a quantitative analysis of myocardial fibrosis burden was performed. Results: Mean age at the time of AV surgery was not statistically different in both groups (AR: 53.3 ± 15.3 years vs. AS: 58.7 ± 17.0 years; p = 0.116). The LV end-diastolic diameter was significantly enlarged in the AR-group when compared to the AS-group (59.4 ± 15.6 vs. 39.7 ± 21.2; p < 0.001). Analysis of beta-AR sensitivity (AR: -6.769 vs. AS: -6.659; p = 0.316) and myocardial fibrosis (AR: 8.9% vs. AS: 11.3%; p = 0.284) showed no significant differences between patients with AS and AR. There was no correlation between myocardial fibrosis and beta-AR sensitivity in the whole study cohort (R = 0.1987; p = 0.100) or in the AS-subgroup (R = 0.009; p = 0.960). However, significant correlation of fibrosis and beta-AR sensitivity was seen in AR-patients (R = 0.363; p = 0.023). Conclusion: More severe myocardial fibrosis was associated with reduced beta-AR sensitivity in patients presenting with AR but not with AS. Therefore, our results suggest that in patients with AR, cellular myocardial dysfunction is present and correlates with the extent of myocardial fibrosis in the myocardium.

Valvular heart disease: shifting the focus to the myocardium

Adverse cardiac remodelling is the main determinant of patient prognosis in degenerative valvular heart disease (VHD). However, to give an indication for valvular intervention, current guidelines include parameters of cardiac chamber dilatation or function which are subject to variability, do not directly reflect myocardial structural changes, and, more importantly, seem to be not sensitive enough in depicting early signs of myocardial dysfunction before irreversible myocardial damage has occurred. To avoid irreversible myocardial dysfunction, novel biomarkers are advocated to help refining indications for intervention and risk stratification. Advanced echocardiographic modalities, including strain analysis, and magnetic resonance imaging have shown to be promising in providing new tools to depict the important switch from adaptive to maladaptive myocardial changes in response to severe VHD. This review, therefore, summarizes the current available evidence on the role of these new imaging biomarkers in degenerative VHD, aiming at shifting the clinical perspective from a valve-centred to a myocardium-focused approach for patient management and therapeutic decision-making.

The myosin activator omecamtiv mecarbil improves wall stress in a rat model of chronic aortic regurgitation

In patients with chronic aortic regurgitation (AR), excessive preload and afterload increase left ventricle wall stress, leading to left ventricular systolic dysfunction. Thus, the objective of the present study was to evaluate the effects of the myosin activator omecamtiv mecarbil (OM) on left ventricle wall stress in an experimental rat model of severe chronic AR. Forty adult male Wistar rats were randomized into two experimental groups: induction of AR (acute phase) by retrograde puncture (n = 34) or a sham intervention (n = 6). Rats that survived the acute phase (n = 18) were randomized into an OM group (n = 8) or a placebo group (n = 10). Equal volumes of OM (1.2 mg/kg/h) or placebo (0.9% NaCl) were continuously infused into the femoral vein over 30 min. OM significantly decreased end-systolic and end-diastolic and maximum wall stress in this experimental rat model of chronic severe AR (p < 0.001) and increased systolic performance assessed by fractional shortening and left ventricle end-systolic diameter; both p < 0.05). These effects were correlated with decreased indices of global cardiac function (cardiac output and stroke volume; p < 0.05) but were not inferior to baseline pump indices. Infusion with placebo did not affect global cardiac function but decreased end-systolic wall stress (p < 0.05) and increased systolic performance (all p < 0.001). In the sham-operated (control) group, OM decreased diastolic wall stress (p < 0.05). Based on these results, OM had a favorable effect on left ventricle wall stress in an experimental rat model of severe chronic AR.

Regional Replacement and Diffuse Interstitial Fibrosis in Aortic Regurgitation: Prognostic Implications From Cardiac Magnetic Resonance

OBJECTIVES

This study used cardiac magnetic resonance (CMR) to assess left ventricular (LV) remodeling in chronic aortic regurgitation (AR) to identify both forms of myocardial fibrosis and examine its association with clinical outcomes.

BACKGROUND

Chronic AR leads to LV remodeling, which is associated with 2 forms of myocardial fibrosis: regional replacement fibrosis that is directly imaged by late gadolinium enhancement (LGE) CMR; and diffuse interstitial fibrosis, which can be inferred by T1 mapping techniques.

METHODS

Patients with chronic AR who were undergoing contrast CMR with T1 mapping for valve assessment from 2011 to 2018 were enrolled. Patients with a confounding etiology of myocardial fibrosis were excluded. In addition to quantification of AR severity and LV volumetrics, LGE and T1 mapping pre- and post-contrast were performed to measure extracellular volume (ECV) and indexed ECV (iECV). Patients were followed up longitudinally to assess for the composite event of death and the need for aortic valve replacement.

RESULTS

A total of 177 patients with isolated chronic AR were included (66% males, median age 58 years [47.0 years-68.0 years]) with a median follow up of 2.5 years (1.07 years-3.56 years). The iECV significantly increased with AR severity (P < 0.001), whereas ECV and replacement fibrosis did not (P = NS). On multivariate analysis, iECV remained associated with the composite event (P = 0.01). On Kaplan-Meier analysis stratified by AR regurgitant fraction (RF) and iECV, patients with AR RF severity ≥30% and iECV ≥24 mL/m² demonstrated the highest event rate.

CONCLUSIONS

Among CMR biomarkers of fibrosis, iECV was more closely associated than replacement fibrosis or ECV with survival free of aortic valve replacement.

Disparate impact of severe aortic and mitral regurgitation on left ventricular dilation

In asymptomatic severe aortic (AR) and mitral regurgitation (MR), left ventricular (LV) dimension criteria were established to guide timing of valve replacement to prevent irreversible LV dysfunction. Given both lesions are primary LV volume overload ''leaks'', it might be expected that both lesions would induce similar impact on the LV and result in equivalent dimension criteria for intervention. However, the dimension-based intervention criteria for AR versus MR (developed through natural history studies), differ markedly. The pathophysiological foundations for such discordance have neither been fully elucidated nor emphasized. This case-based treatise compares the two regurgitant lesions with respect to: (a) ''total regurgitant circuits''; (b) ''driving pressures'' resulting in LV volume overload from each respective ''leak''; and (c) volume and afterload wall stresses imposed on the LV.Key points The ''total circuits'' of volume overload differ: The AR circuit includes the LV and systemic vasculature, whereas MR includes the LV ejecting into the left atrium/pulmonary veins and systemic circulation. The ''driving pressure'' of regurgitation and afterload are high with AR and low with MR. Differing ''total circuits'' and ''driving pressures'' impose disparate wall stresses upon the LV. Parallel and serial sarcomere replication occurs in AR, while only serial replication occurs in MR. It therefore follows that for regurgitation of similar severities, AR results in greater LV dilation at the point of irreversible myocardial dysfunction compared to MR. These considerations may explain, at least in part, the disparate dimension criteria employed for valve intervention for severe AR vs MR.

Myocardial Scar and Mortality in Chronic Aortic Regurgitation

Background

Chronic aortic regurgitation (AR) can be associated with myocardial scarring. It is unknown if scarring in AR is linked to poor outcomes and whether aortic valve replacement impacts this association. We investigated the relationship of myocardial scarring to mortality in chronic AR using cardiac magnetic resonance.

Methods and Results

We enrolled patients with moderate or greater AR between 2009 and 2019 and performed a blinded assessment of left ventricle remodeling, AR severity, and presence and extent of myocardial scarring by late gadolinium enhancement. The primary outcome was all‐cause mortality. We followed 392 patients (median age 62 [interquartile range, 51–71] years), and 78.1% were men, and 25.8% had bicuspid valves. Median aortic valve regurgitant volume was 39 mL (interquartile range, 30–60). Myocardial scar was present in 131 (33.4%) patients. Aortic valve replacement was performed in 165 (49.1%) patients. During follow‐up, up to 10.8 years (median 32.3 months [interquartile range, 9.8–69.5]), 51 patients (13%) died. Presence of myocardial scar (hazard ratio [HR], 3.62; 95% CI, 2.06–6.36; P<0.001), infarction scar (HR, 4.94; 95% CI, 2.58–9.48; P<0.001), and noninfarction scar (HR, 2.75; 95% CI, 1.39–5.44; P<0.004) were associated with mortality. In multivariable analysis, the presence of scar remained independently associated with death (HR, 2.53; 95% CI, 1.15–5.57; P=0.02). Among patients with myocardial scar, aortic valve replacement was independently associated with a lower risk of mortality (HR, 0.34; 95% CI, 0.12–0.97; P=0.03), even after adjustment for confounders.

Conclusions

In aortic regurgitation, myocardial scar is independently associated with a 2.5‐fold increase risk in mortality. Aortic valve replacement was associated with a reduction in risk of mortality in patients with scarring.

Exploratory assessment of left ventricular strain-volume loops in severe aortic valve diseases

KEY POINTS

Severe aortic valve diseases are common cardiac abnormalities that are associated with poor long-term survival. Before any reduction in left ventricular (LV) function, the left ventricle undergoes structural remodelling under the influence of changing haemodynamic conditions. In this study, we combined temporal changes in LV structure (volume) with alterations in LV functional characteristics (strain, ԑ) into a ԑ-volume loop, in order to provide novel insight into the haemodynamic cardiac consequences of aortic valve diseases in those with preserved LV ejection fraction. We showed that our novel ԑ-volume loop and the specific loop characteristics provide additional insight into the functional and mechanical haemodynamic consequences of severe aortic valve diseases (with preserved LV ejection fraction). Finally, we showed that the ԑ-volume loop characteristics provide discriminative capacity compared with conventional measures of LV function.

ABSTRACT

The purpose of this study was to examine left ventricular (LV) strain (ԑ)-volume loops to provide novel insight into the haemodynamic cardiac consequences of aortic valve stenosis (AS) and aortic valve regurgitation (AR). Twenty-seven participants were retrospectively recruited: AR (n = 7), AS (n = 10) and control subjects (n = 10). Standard transthoracic echocardiography was used to obtain apical four-chamber images to construct ԑ-volume relationships, which were assessed using the following parameters: early systolic ԑ (ԑ_ES); slope of ԑ-volume relationship during systole (Sslope); end-systolic peak ԑ (peak ԑ); and diastolic uncoupling (systolic ԑ-diastolic ԑ at same volume) during early diastole (UNCOUP_ED) and late diastole (UNCOUP_LD). Receiver operating characteristic curves were used to determine the ability to detect impaired LV function. Although LV ejection fraction was comparable between groups, longitudinal peak ԑ was reduced compared with control subjects. In contrast, ԑ_ES and Sslope were lower in both pathologies compared with control subejcts (P < 0.01), but also different between AS and AR (P < 0.05). UNCOUP_ED and UNCOUP_LD were significantly higher in both patient groups compared with control subjects (P < 0.05). Receiver operating characteristic curves revealed that loop characteristics (AUC = 0.99, 1.00 and 1.00; all P < 0.01) were better able then peak ԑ (AUC = 0.75, 0.89 and 0.76; P = 0.06, <0.01 and 0.08, respectively) and LV ejection fraction (AUC = 0.56, 0.69 and 0.69; all P > 0.05) to distinguish AS vs control, AR vs control and AS vs AR groups, respectively. Temporal changes in ԑ-volume characteristics provide novel insight into the haemodynamic cardiac impact of AS and AR. Contrary to traditional measures (i.e. ejection fraction, peak ԑ), these novel measures successfully distinguish between the haemodynamic cardiac impact of AS and AR.

Myocardial Integrated Backscatter in Obese Adolescents: Associations with Measures of Adiposity and Left Ventricular Deformation

Background

Myocardial fibrosis has been proposed to play an important pathogenetic role in left ventricular (LV) dysfunction in obesity. This study tested the hypothesis that calibrated integrated backscatter (cIB) as a marker of myocardial fibrosis is altered in obese adolescents and explored its associations with adiposity, LV myocardial deformation, and metabolic parameters.

Methods/Principal Findings

Fifty-two obese adolescents and 38 non-obese controls were studied with conventional and speckle tracking echocardiography. The average cIB of ventricular septum and LV posterior wall was measured. In obese subjects, insulin resistance as estimated by homeostasis model assessment (HOMA-IR) and glucose tolerance were determined. Compared with controls, obese subjects had significantly greater cIB of ventricular septum (-16.8±7.8 dB vs -23.2±7.8 dB, p<0.001), LV posterior wall (-20.5±5.6 dBvs -25.0±5.1 dB, p<0.001) and their average (-18.7±5.7 dB vs -24.1±5.0 dB, p<0.001). For myocardial deformation, obese subjects had significantly reduced LV longitudinal systolic strain rate (SR) (p = 0.045) and early diastolic SR (p = 0.015), and LV circumferential systolic strain (p = 0.008), but greater LV longitudinal late diastolic SR (p<0.001), and radial early (p = 0.037) and late (p = 0.002) diastolic SR than controls. For the entire cohort, myocardial cIB correlated positively with body mass index (r = 0.45, p<0.001) and waist circumference (r = 0.45, p<0.001), but negatively with LV circumferential systolic strain (r = -0.23, p = 0.03) and systolic SR (r = -0.25, p = 0.016). Among obese subjects, cIB tended to correlate with HOMA-IR (r = 0.26, p = 0.07).

Conclusion

Obese adolescents already exhibit evidence of increased myocardial fibrosis, which is associated with measures of adiposity and impaired LV circumferential myocardial deformation.

Comparison of Left Ventricular Myocardial Structure and Function in Patients with Aortic Stenosis and Those with Pure Aortic Regurgitation

OBJECTIVE

We aimed to support the structural and functional distinction between aortic stenosis (AS) and aortic regurgitation (AR).

METHODS

Biopsy specimens taken from 70 selected patients (35 with AS and 35 with AR) undergoing aortic valve replacement (AVR) were analyzed for their cardiomyocyte dimensions and structure, interstitial fibrosis and contractile function. To determine normal values of contractile function, 10 donor hearts were analyzed.

RESULTS

Cardiomyocyte diameter was higher in AS than in AR (22.7 ± 2.2 vs. 13.2 ± 0.7 µm, p < 0.001). Length was higher in AR (121.2 ± 9.4 vs. 95.6 ± 3.7 µm, p < 0.001). Collagen volume fraction was increased in both AS and AR, but was lower in the AS specimens (7.7 ± 2.3 vs. 8.9 ± 2.3, p = 0.01). Myofibril density was reduced in AR (38 ± 4 vs. 48 ± 5%, p < 0.001). Cardiomyocyte diameter and length were closely linked to the relative left ventricular (LV) wall thickness (R² = 0.85, p < 0.001 and R² = 0.68, p = 0.003). The cardiomyocytes of AS patients had higher F_passive (6.6 ± 0.3 vs. 4.6 ± 0.2 kN/m², p < 0.001), but their total force was comparable. F_passive was also significantly higher in AS patients with restrictive rather than pseudo-normal LV filling (7.3 ± 0.5 vs. 6.7 ± 0.6, p = 0.004). In AS patients, but not in AR patients, F_passive showed a significant association with the cardiomyocyte diameter (R² = 0.88, p < 0.001 vs. R² = 0.31, p = 0.6).

CONCLUSIONS

LV myocardial structure and function differ in AS and AR, allowing for compensative adjustment of the diastolic/systolic properties of the myocardium. © 2015 S. Karger AG, Basel.

Ventricular mechanics in patients with aortic valve disease: longitudinal, radial, and circumferential components

BACKGROUND

Reduced long-axis shortening despite enhanced global function has been reported in aortic stenosis. We sought to improve the understanding of this phenomenon using multi-dimensional strain analysis in conjunction with the evaluation of left ventricular rotation and twist - ventricular torsion - using tissue Doppler techniques.

METHODS

A total of 57 patients with variable severity of aortic stenosis, aortic regurgitation, or mixed aortic valve disease, subdivided into six groups, were studied. Ventricular morphology was assessed using long-axis/short-axis and mass/volume ratios, afterload using end-systolic meridional wall stress, and global performance using ejection fraction. The circumferential and longitudinal strain was measured from two-dimensional images, and left ventricular rotation and twist were estimated as the difference in rotation between the base and apex of the ventricle.

RESULTS

Aortic stenosis was associated with higher mass/volume, ejection fraction, circumferential strain and left ventricular rotation and twist, significantly lower end-systolic wall stress, and a trend towards lower longitudinal strain compared with normal. Myocardial mechanics in aortic regurgitation were normal despite ventricular dilation. Mixed aortic valve disease showed findings similar to aortic stenosis. Left ventricular rotation and twist correlated with midwall circumferential strain (r = 0.62 and p < 0.0001), endocardial circumferential strain (r = 0.61 and p < 0.0001), and end-systolic wall stress (r = 0.48 and p < 0.0001), but not with longitudinal strain (r = 0.18 and p > 0.05).

CONCLUSIONS

Myocardial mechanics are normal in patients with aortic regurgitation, independent of abnormalities in cardiac geometry. Conversely, in aortic stenosis and mixed aortic valve disease, significant alterations in the patterns of fibre shortening are found. The effects of stenosis on cardiac function seem to dominate the effect of ventricular remodelling.

Risk factors for late valve-related mortality after aortic valve replacement in elderly patients

PURPOSE

Few recent studies have examined the long-term outcomes after aortic valve replacement (AVR), and independent predictors for long-term survival and valve-related mortality have not been elucidated.

METHODS

From January 1993 to December 2009, 132 elderly patients (≥70 years old) with aortic stenosis underwent AVR in our hospital. The patients comprised 61 men and71 women with a mean age of 76.1 ± 3.7 years. Patients with acute or old myocardial infarction, mitral valve disease, and re-do surgery were not included in this study. Risk factors for late valve-related mortality were examined.

RESULTS

The 5-year freedom from valve-related mortality rate was 89.6%. The following significant independent risk factors for late valve-related mortality were identified:increase in the preoperative left ventricular mass index (hazard ratio, 1.10 [per 10 g/m(2)];p = 0.040); lack of sinus rhythm (hazard ratio, 7.11; p = 0.005); peak transvalvular pressure gradient of <60 mmHg (hazard ratio, 7.48; p = 0.008).

CONCLUSION

In the elderly, AVR should be performed at an early stage of aortic stenosis, before an increase in the left ventricular mass index has occured, and while the heart rhythm is in sinus rhythm and the peak transvalvular pressure gradient is high.

Transmural compensation of myocardial deformation to preserve left ventricular ejection performance in chronic aortic regurgitation

BACKGROUND

In patients with chronic aortic regurgitation (AR), systolic wall stress and volume overload affects left ventricular (LV) systolic function and remodeling. The aim of this study was to assess transmural rearrangements of myocardial deformation to preserve LV ejection performances using speckle-tracking echocardiography in patients with chronic AR.

METHODS

Ninety patients with AR were enrolled. On LV short-axis images, total, inner, and outer radial strain and circumferential strain at the inner, mid, and outer layers were calculated. On apical four-chamber images, endocardial longitudinal strain was calculated. End-systolic wall stresses were calculated using previous methods.

RESULTS

AR severities were classified as moderate in 31 patients, severe and preserved LV ejection fraction (LVEF) (≥50%) in 42 patients, and severe and reduced LVEF (<50%) in 17 patients. Longitudinal strain was decreased even in the moderate AR group, despite normal end-systolic wall stress. Inner radial strain progressively decreased with increasing end-systolic wall stress, whereas outer radial strain in the moderate and severe AR and preserved LVEF groups was higher than in the control group. Consequently, total radial strain was preserved even in the severe AR and preserved LVEF groups with increased end-systolic wall stress. Similarly, despite reduced inner circumferential strain, outer circumferential strain was higher in the severe AR and preserved LVEF group than in the control group. All strain parameters were lower in the severe AR and reduced LVEF group with dramatically increased end-systolic wall stress than in other groups.

CONCLUSIONS

Transmural strain analysis revealed that subendocardial dysfunction accompanied by increased wall thickening at the subepicardium may be a compensatory mechanism of wall thickening to preserve LVEF in patients with chronic AR.

Evaluation and management of aortic valve and root disease

Aortic valve disease manifests in the form of stenosis, regurgitation, or some combination, yielding either excessive afterload and/or excessive preload on the left ventricle. Aortic root disease may affect valvular function, causing regurgitation; may simply be coexistent with stenotic aortic valvular disease; or may exist despite normal aortic valve function. Indications for intervening on aortic valve or root disease are determined by the presence of symptoms, by the pathology's impact on left ventricular function, or by the inherent risk of aortic catastrophe (dissection, disruption, or sudden death). Aortic valvular and root diseases are primarily treated by surgical replacement of the pathologic structures. Mechanical aortic valve replacement has long-term durability but requires continuous anticoagulation. Bioprostheses do not require anticoagulation but have more limited durability. Valve-sparing aortic root replacement and aortic valve repair offer the potential for indefinite durability without the need for anticoagulation but are technically more difficult to perform and require more stringent selection criteria based on determining the reparability of an aortic valve. Emerging percutaneous valve technologies offer new hope for patients who are not candidates for aortic valve surgery, but the applicability and durability of percutaneous aortic valves are not yet known. Timely and appropriate intervention in aortic valve and root disease can result in the restoration of a normal life span for patients with aortic valvular and/or root disease.

Thallium-201 single-photon emission computed tomography: quantitative assessment of left ventricular perfusion and structural change in patients with chronic aortic regurgitation

BACKGROUND

Previously, perfusion defect in the left ventricle was detected by thallium-201 (201T1) single-photon emission computed tomography (SPECT) in aortic regurgitation (AR). The significance of 201T1 SPECT, however, has not been clarified. Limited information is available regarding the relationship between functional characteristics and scintigraphic findings.

HYPOTHESIS

The purpose of this study was to elucidate the role of exercise 201T1 SPECT in assessing myocardial perfusion or structural change in chronic AR. We examined the correlation between 201T1 scintigraphic findings and left ventricular (LV) function parameters in 11 patients.

METHODS

Defect volume ratio (DVR) in exercise 201T1 SPECT was used as a parameter of the range of abnormal thallium distribution. Left ventricular parameters were obtained by right and retrograde left cardiac catheterizations. The relationship between DVR and the parameters was analyzed.

RESULTS

The DVR ranged from 1.0 to 28.3% (average 12.1 + 8.5 %). There was a significant correlation (r = 0.77, p < 0.05) between DVR and end-diastolic volume index (EDVI), a definite correlation (r = 0.66, p < 0.01) between DVR and end-systolic volume index (ESVI), and a good correlation (r = -0.77, p <0.05) between DVR and end-systolic wall stress (ESS)/ ESVI; however, no such correlation was found between DVR and ejection fraction.

CONCLUSION

All patients showed abnormal defects in 201T1 accumulation scattered across the entire ventricle. A strong correlation between DVR and ESS/ESVI, an index of myocardial contractility, was a major finding of this study, suggesting a significant association between abnormal myocardial perfusion or structural alteration and reduction in myocardial contractility in chronic AR.

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.