Assessment of Left Ventricular Reverse Remodeling by Cardiac MRI in Patients Undergoing Repair Surgery for Severe Aortic or Mitral Regurgitation

Aortic Regurgitation: From Valvular to Myocardial Dysfunction

Chronic aortic regurgitation (AR) leads to volume overload in the left ventricle (LV), which is well tolerated for years. In this condition, the LV usually dilates with minimal reduction in the ejection fraction (EF), even in the absence of symptoms. Echocardiography is the primary imaging test used to quantify AR. However, no single assessment of Doppler measures is accurate and precise in individual patients; therefore, the integration of multiple parameters is necessary. Recent guidelines recommend surgical treatment for severe AR in patients who are symptomatic or have an LVEF < 55% and an end-systolic diameter > 50 mm. Nevertheless, advances in imaging technology have improved the quantification of AR and the assessment of LV subclinical dysfunction. It is widely recognized that patients who undergo aortic valve replacement/repair (AVR) due to symptoms or a low LVEF experience worse outcomes than those undergoing AVR for non-Class I indications. In fact, subclinical irreversible myocardial damage may occur in clinically well-compensated and closely monitored patients while awaiting formal surgical indications. This condition could be prevented by the use of multimodal imaging parameters, in particular longitudinal LV strain and magnetic resonance imaging. In addition, better cut-off values for mortality predictors should be established. This review aims to identify simple models that integrate several echocardiographic and cardiac magnetic resonance-derived parameters to predict the optimal timing of surgical treatment in asymptomatic patients with chronic severe AR.

Multiscale Finite Element Modeling of Left Ventricular Growth in Simulations of Valve Disease

Multiscale models of the cardiovascular system are emerging as effective tools for investigating the mechanisms that drive ventricular growth and remodeling. These models can predict how molecular-level mechanisms impact organ-level structure and function and could provide new insights that help improve patient care. MyoFE is a multiscale computer framework that bridges molecular and organ-level mechanisms in a finite element model of the left ventricle that is coupled with the systemic circulation. In this study, we extend MyoFE to include a growth algorithm, based on volumetric growth theory, to simulate concentric growth (wall thickening/thinning) and eccentric growth (chamber dilation/constriction) in response to valvular diseases. Specifically in our model, concentric growth is controlled by time-averaged total stress along the fiber direction over a cardiac cycle while eccentric growth responds to time-averaged intracellular myofiber passive stress over a cardiac cycle. The new framework correctly predicted different forms of growth in response to two types of valvular diseases, namely aortic stenosis and mitral regurgitation. Furthermore, the model predicted that LV size and function are nearly restored (reversal of growth) when the disease-mimicking perturbation was removed in the simulations for each valvular disorder. In conclusion, the simulations suggest that time-averaged total stress along the fiber direction and time-averaged intracellular myofiber passive stress can be used to drive concentric and eccentric growth in simulations of valve disease.

Impact of Recurrent Mitral Regurgitation on Left Ventricular Mass Regression and Cardiac Events following Mitral Valve Repair

BACKGROUND

Mitral valve regurgitation results in volume overload, followed by left ventricular remodeling. Variation of reverse remodeling following mitral repair influences the clinical outcomes. We aimed to evaluate the association between recurrent mitral regurgitation and mass regression following mitral valve repair and the impact on major adverse cardiovascular events.

METHODS

A retrospective cohort study was conducted on 164 consecutive patients with severe mitral regurgitation who underwent elective mitral valve repair. Subgroups were classified based on the presence of recurrent mitral regurgitation exceeding moderate severity. The hemodynamic parameters were evaluated according to geometry, mass, and function with Doppler echocardiography before and after surgery. Cox regression analysis was performed to evaluate the association between hemodynamics and mass regression and clinical outcomes.

RESULTS

The results for MR indicated 110 cases with non-recurrent MR and 54 with recurrent MR, along with 31 major adverse cardiovascular events. The tracked echocardiographic results revealed less reduction in dimension and volume, along with less mass regression in the recurrent MR subgroup. Significant differences were revealed in the relative change of the LV end-diastolic volume index and relative mass regression between subgroups. The relative change in the LVEDVI was proportionally correlated with relative mass regression. Cox regression analysis identified correlations with major adverse cardiovascular events, including suture annuloplasty, recurrent mitral regurgitation, tracked LV mass, relative LV mass regression, and systolic dysfunction.

CONCLUSION

LV mass regression and relative change of the LV end-diastolic volume could be risk predictors of recurrent mitral regurgitation. The extent of LV mass regression is correlated with adverse cardiac events.

Imaging Methods for Evaluation of Chronic Aortic Regurgitation in Adults: JACC State-of-the-Art Review

A global multidisciplinary workshop was convened to discuss the multimodality diagnostic evaluation of aortic regurgitation (AR). Specifically, the focus was on assessment tools for AR severity and analyzing evolving data on the optimal timing of aortic valve intervention. The key concepts from this expert panel are summarized as: 1) echocardiography is the primary imaging modality for assessment of AR severity; however, when data is incongruent or incomplete, cardiac magnetic resonance may be helpful; 2) assessment of left ventricular size and function is crucial in determining the timing of intervention; 3) recent evidence suggests current cutpoints for intervention in asymptomatic severe AR patients requires further scrutiny; 4) left ventricular end-systolic volume index has emerged as an additional parameter that has promise in guiding timing of intervention; and 5) the role of additional factors (including global longitudinal strain, regurgitant fraction, and myocardial extracellular volume) is worthy of future investigation.

Cardiac reverse remodeling in primary mitral regurgitation: mitral valve replacement vs. mitral valve repair

BACKGROUND

When feasible, guidelines recommend mitral valve repair (MVr) over mitral valve replacement (MVR) to treat primary mitral regurgitation (MR), based upon historic outcome studies and transthoracic echocardiography (TTE) reverse remodeling studies. Cardiovascular magnetic resonance (CMR) offers reference standard biventricular assessment with superior MR quantification compared to TTE. Using serial CMR in primary MR patients, we aimed to investigate cardiac reverse remodeling and residual MR post-MVr vs MVR with chordal preservation.

METHODS

83 patients with ≥ moderate-severe MR on TTE were prospectively recruited. 6-min walk tests (6MWT) and CMR imaging including cine imaging, aortic/pulmonary through-plane phase contrast imaging, T1 maps and late-gadolinium-enhanced (LGE) imaging were performed at baseline and 6 months after mitral surgery or watchful waiting (control group).

RESULTS

72 patients completed follow-up (Controls = 20, MVr = 30 and MVR = 22). Surgical groups demonstrated comparable baseline cardiac indices and co-morbidities. At 6-months, MVr and MVR groups demonstrated comparable improvements in 6MWT distances (+ 57 ± 54 m vs + 64 ± 76 m respectively, p = 1), reduced indexed left ventricular end-diastolic volumes (LVEDVi; - 29 ± 21 ml/m2 vs - 37 ± 22 ml/m2 respectively, p = 0.584) and left atrial volumes (- 23 ± 30 ml/m2 and - 39 ± 26 ml/m2 respectively, p = 0.545). At 6-months, compared with controls, right ventricular ejection fraction was poorer post-MVr (47 ± 6.1% vs 53 ± 8.0% respectively, p = 0.01) compared to post-MVR (50 ± 5.7% vs 53 ± 8.0% respectively, p = 0.698). MVR resulted in lower residual MR-regurgitant fraction (RF) than MVr (12 ± 8.0% vs 21 ± 11% respectively, p = 0.022). Baseline and follow-up indices of diffuse and focal myocardial fibrosis (Native T1 relaxation times, extra-cellular volume and quantified LGE respectively) were comparable between groups. Stepwise multiple linear regression of indexed variables in the surgical groups demonstrated baseline indexed mitral regurgitant volume as the sole multivariate predictor of left ventricular (LV) end-diastolic reverse remodelling, baseline LVEDVi as the most significant independent multivariate predictor of follow-up LVEDVi, baseline indexed LV end-systolic volume as the sole multivariate predictor of follow-up LV ejection fraction and undergoing MVR (vs MVr) as the most significant (p < 0.001) baseline multivariate predictor of lower residual MR.

CONCLUSION

In primary MR, MVR with chordal preservation may offer comparable cardiac reverse remodeling and functional benefits at 6-months when compared to MVr. Larger, multicenter CMR studies are required, which if the findings are confirmed could impact future surgical practice.

Predictors and clinical implications of residual mitral regurgitation following left ventricular assist device therapy

BACKGROUND

Correction of mitral regurgitation (MR) at the time of left ventricular assist device (LVAD) implantation remains controversial. There is conflicting evidence regarding the clinical impact of residual MR, and studies have not examined whether MR aetiology or right heart function impacts the likelihood of residual MR.

METHODS

This is a retrospective single-centre study of 155 consecutive patients with LVAD implantation from January 2011 to March 2020. Exclusion criteria were no MR pre-LVAD (n=8), inaccessible echocardiography (n=9), duplicate records (n=10) and concomitant mitral valve repair (n=1). Statistical analysis was performed using STATA V.16 and SPSS V.24.

RESULTS

Carpentier IIIb MR aetiology was associated with more severe MR pre-LVAD (severe 18/27 (67%) vs non-severe 32/91 (35%), p=0.004) and a higher likelihood of residual MR (8/11 (72%) vs 30/74 (41%), p=0.045). Of 95 patients with significant MR pre-LVAD, 15 (16%) had persistent significant MR, which was associated with higher mortality (p=0.006), post-LVAD right ventricle (RV) dilatation (10/15 (67%) vs 28/80 (35%), p=0.022) and RV dysfunction (14/15 (93%) vs 35/80 (44%), p<0.001). Aside from ischaemic aetiology, other pre-LVAD parameters that were associated with significant residual MR included left ventricular end-systolic diameter (LVESD) (6.9 cm (5.7-7.2) vs 5.9 cm (5.5-6.5), p=0.043), left atrial volume index (LAVi) (78 mL/m² (56-88) vs 57 mL/m² (47-77), p=0.021), posterior leaflet displacement (2.5 cm (2.3-2.9) vs 2.3 cm (1.9-2.7), p=0.042) and basal right ventricular end-diastolic diameter (RVEDD) (5.1±0.8 cm vs 4.5±0.8 cm, p=0.010).

CONCLUSION

LVAD therapy improves MR and tricuspid regurgitation severity in the majority, but 14% have persistent significant residual MR, associated with right ventricular dysfunction and higher long-term mortality. This may be predicted pre-LVAD by greater LVESD, RVEDD and LAVi and by ischaemic aetiology.

Proteomic Analysis in Valvular Cardiomyopathy: Aortic Regurgitation vs. Aortic Stenosis

Left ventricular (LV) reverse remodeling after aortic valve (AV) surgery is less predictable in chronic aortic regurgitation (AR) than in aortic stenosis (AS). We aimed to disclose specific LV myocardial protein signatures possibly contributing to differential disease progression. Global protein profiling of LV myocardial samples excised from the subaortic interventricular septum in patients with isolated AR or AS undergoing AV surgery was performed using liquid chromatography–electrospray ionization–tandem mass spectrometry. Based on label-free quantitation protein intensities, a logistic regression model was calculated and adjusted for age, sex and protein concentration. Web-based functional enrichment analyses of phenotype-associated proteins were performed utilizing g:Profiler and STRING. Data are available via ProteomeXchange with identifier PXD039662. Lysates from 38 patients, including 25 AR and 13 AS samples, were analyzed. AR patients presented with significantly larger LV diameters and volumes (end-diastolic diameter: 61 (12) vs. 48 (13) mm, p < 0.001; end-diastolic volume: 180.0 (74.6) vs. 92.3 (78.4), p = 0.001). A total of 171 proteins were associated with patient phenotype: 117 were positively associated with AR and the enrichment of intracellular compartment proteins (i.e., assigned to carbohydrate and nucleotide metabolism, protein biosynthesis and the proteasome) was detected. Additionally, 54 were positively associated with AS and the enrichment of extracellular compartment proteins (i.e., assigned to the immune and hematopoietic system) was observed. In summary, functional enrichment analysis revealed specific AR- and AS-associated signatures of LV myocardial proteins.

Long-term outcomes after aortic valve surgery in patients with aortic regurgitation with preserved ejection fraction and left ventricular dilation

OBJECTIVES

This study aims to assess the long-term outcomes and prognostic predictors of asymptomatic patients with severe aortic regurgitation (AR) accompanied by left ventricular ejection fraction (LVEF) ≥ 55% and left ventricular end-diastolic diameter (LVEDD) > 65 mm undergoing aortic valve replacement (AVR).

METHODS

We retrospectively studied 291 consecutive asymptomatic patients with severe AR accompanied by LVEF ≥ 55% and LVEDD > 65 mm undergoing AVR from January 2000 to December 2013. The long-term outcomes and prognostic predictors were evaluated.

RESULTS

There were 2 (0.7%) in-hospital deaths caused by multiple organ failure. The overall survival rate was 95.2% at 5 years, 89.9% at 10 years, 85.9% at 15 years, and 85.9% at 20 years. The left ventricular end-systolic volume index (LVESVi) was an independent predictor of overall mortality, with 59 ml/m² being the best cut-off value. The left ventricular (LV) dimension decreased within 1 year after surgery and sustained thereafter. There were 15.5% of patients had incomplete LV reverse remodeling. LVESVi was an independent predictor of incomplete LV reverse remodeling, with 56 ml/m² being the best cut-off value.

CONCLUSIONS

AVR can be performed with an acceptable outcome in patients with severe AR accompanied by LVEF ≥ 55% and LVEDD > 65 mm. The LVESVi has the best predictive value for prognosis and the cut-off value is 59 ml/m², and has the best predictive value for incomplete LV reverse remodeling and the cut-off value is 56 ml/m².

Assessment of valve implantation in the descending aorta as an alternative for aortic regurgitation patients not treatable with conventional procedures

BACKGROUND

Aortic Regurgitation (AR) produces the entrance of an abnormal amount of blood in the left ventricle. This disease is responsible for high morbidity and mortality worldwide and may be caused by an aortic valve dysfunction. Surgical and transcatheter aortic valve replacement (TAVR) are the current options for treating AR. They have replaced older procedures such as Hufnagel's one. However, some physicians have reconsidered this procedure as a less aggressive alternative for patients not eligible for surgical or TAVR. Although Hufnagel suggested a 75% regurgitation reduction when a valve is placed in the descending aorta, a quantification of this value has not been reported.

METHODS

In this paper, CFD/FSI numerical simulation is conducted on an idealized geometry. We quantify the effect of placing a bileaflet mechanical heart valve in the descending aorta on a moderate-severe AR case. A three-element Windkessel model is employed to prescribe pressure outlet boundary conditions. We calculate the resulting flow rates and pressures at the aorta and first-generation vessels. Moreover, we evaluate several indices to assess the improvement due to the valve introduction.

RESULTS AND CONCLUSIONS

Regurgitation fraction (RF) is reduced from 37.5% (without valve) to 18.0% (with valve) in a single cardiac cycle. This reduction clearly shows the remarkable efficacy of the rescued technique. It will further ameliorate the left ventricle function in the long-term. Moreover, the calculations show that the implantation in that location introduces fewer incompatibilities' risks than a conventional one. The proposed methodology can be extended to any particular conditions (pressure waveforms/geometry) and is designed to assess usual clinical parameters employed by physicians.

Late plasma exosome microRNA-21-5p depicts magnitude of reverse ventricular remodeling after early surgical repair of primary mitral valve regurgitation

Introduction

Primary mitral valve regurgitation (MR) results from degeneration of mitral valve apparatus. Mechanisms leading to incomplete postoperative left ventricular (LV) reverse remodeling (Rev-Rem) despite timely and successful surgical mitral valve repair (MVR) remain unknown. Plasma exosomes (pEXOs) are smallest nanovesicles exerting early postoperative cardioprotection. We hypothesized that late plasma exosomal microRNAs (miRs) contribute to Rev-Rem during the late postoperative period.

Methods

Primary MR patients (n = 19; age, 45-71 years) underwent cardiac magnetic resonance imaging and blood sampling before (T0) and 6 months after (T1) MVR. The postoperative LV Rev-Rem was assessed in terms of a decrease in LV end-diastolic volume and patients were stratified into high (HiR-REM) and low (LoR-REM) LV Rev-Rem subgroups. Isolated pEXOs were quantified by nanoparticle tracking analysis. Exosomal microRNA (miR)-1, -21-5p, -133a, and -208a levels were measured by RT-qPCR. Anti-hypertrophic effects of pEXOs were tested in HL-1 cardiomyocytes cultured with angiotensin II (AngII, 1 μM for 48 h).

Results

Surgery zeroed out volume regurgitation in all patients. Although preoperative pEXOs were similar in both groups, pEXO levels increased after MVR in HiR-REM patients (+0.75-fold, p = 0.016), who showed lower cardiac mass index (-11%, p = 0.032). Postoperative exosomal miR-21-5p values of HiR-REM patients were higher than other groups (p < 0.05). In vitro, T1-pEXOs isolated from LoR-REM patients boosted the AngII-induced cardiomyocyte hypertrophy, but not postoperative exosomes of HiR-REM. This adaptive effect was counteracted by miR-21-5p inhibition.

Summary/Conclusion

High levels of miR-21-5p-enriched pEXOs during the late postoperative period depict higher LV Rev-Rem after MVR. miR-21-5p-enriched pEXOs may be helpful to predict and to treat incomplete LV Rev-Rem after successful early surgical MVR.

Stage-based approach to predict left ventricular reverse remodeling after mitral repair

Background

Although predictors of reverse left ventricular (LV) remodeling postmitral valve repair are critical for guiding perioperative decision‐making, there remains a paucity of randomized, prospective data to support the criteria that potential predictor variables must meet.

Methods and Results

The CAMRA CardioLink‐2 randomized trial allocated 104 patients to either leaflet resection or preservation strategies for mitral repair. The correlation of indexed left ventricular end‐systolic volume (LVESVI), indexed left ventricular end‐diastolic volume (LVEDVI), and left ventricular ejection fraction (LVEF) were tested with univariate analysis and subsequently with multivariate analysis to determine independent predictors of reverse remodeling at discharge and at 12 months postoperatively. At discharge, both LVESVI and LVEDVI were independently associated with their preoperative values (p < .001 for both) and LVEF by preoperative LVESVI (p < .001). Mitral ring size was favorably associated with the change in LVESVI (p < .05) and LVEF (p < .01) from predischarge to 12 months, while the mean mitral valve gradient after repair was adversely associated with the change in LVESVI (p < .05) and LVEDVI (p < .05). No significant associations were found between reverse remodeling and coaptation height nor mitral repair technique.

Conclusions

Beyond confirming the lack of impact of mitral repair technique on reverse remodeling, this investigation suggests that recommending surgery before significant LV dilatation or dysfunction, as well as higher postoperative mitral valve hemodynamic performance, may enhance remodeling capacity following mitral repair.

Mitral repair with leaflet preservation versus leaflet resection and ventricular reverse remodeling from a randomized trial

OBJECTIVES

In the Canadian Mitral Research Alliance (CAMRA) Trial CardioLink-2 leaflet resection versus preservation techniques for posterior leaflet prolapse was investigated and no difference was shown in their effect on mean mitral gradient at peak exercise at 12 months postoperatively. The purpose of this subanalysis was to evaluate the effect of the 2 strategies on left ventricular (LV) reverse remodeling after repair.

METHODS

A total of 104 patients were randomized to either a leaflet resection or leaflet preservation strategy. Echocardiograms, performed at baseline (preoperative), predischarge, and 12 months postoperatively, were analyzed in a blinded fashion at a core laboratory.

RESULTS

All patients underwent successful mitral repair. At discharge, 3 patients showed moderate mitral regurgitation, whereas the remainder showed mild or less regurgitation. Compared with the baseline echocardiogram, the indexed end diastolic volume was reduced at the discharge echocardiogram (P < .0001) and was further reduced at the 12-month echocardiogram (P = .01). In contrast, the indexed end systolic volume did not significantly change from baseline assessed at the predischarge echocardiogram (P = .32) but improved at 12 months postoperatively (P < .0001), resulting in a corresponding improvement in ejection fraction at 12 months (P < .0001). The type of mitral repair strategy had no significant effect on LV reverse remodeling trends.

CONCLUSIONS

The mitral repair strategies used did not influence postoperative LV reverse remodeling, which occurred in stages. Although LV end diastolic dimensions recovered before discharge, improvements in LV end systolic dimension were evident 12 months after repair.

Mitral Regurgitation in Patients With Coexisting Chronic Aortic Regurgitation: An Evidence-Based Narrative Review

Chronic aortic regurgitation (AR) frequently leads to significant downstream changes to the left ventricle and pulmonary vasculature; these structural and physiologic changes result in lower- than expected patient survival. Progressive, uncorrected AR can lead to left ventricle dilation and subsequent mitral valve leaflet tethering, as well as mitral annular dilation, resulting in secondary mitral regurgitation (MR) in up to 45% of patients. Surgical aortic valve replacement (AVR) improves secondary MR in most patients, but survival is significantly lower in those patients who do not show improvement in MR after AVR. Thus, there is considerable debate on whether the mitral valve should be intervened upon at the time of the AVR. In this review, the authors address the long-term outlook for patients with chronic AR and concurrent MR. The authors also review the available evidence on concomitant mitral valve surgery in patients undergoing AVR for AR. Lastly, this narrative review examines the recent advances in transcatheter mitral valve repair and replacement, and explores the potential role of transcatheter mitral therapies in patients with secondary MR due to AR.

Cardiac Magnetic Resonance in Valvular Heart Disease: Assessment of Severity and Myocardial Remodeling

Cardiac magnetic resonance (CMR) has emerged as the gold standard in assessing ventricular mass, volume, and systolic function. Due to these and other strengths, CMR has increasingly been used to study valvular heart disease (VHD) and resultant cardiac remodeling. By using CMR to assess flow, limitations in echocardiographic assessment of VHD can be overcome, particularly in regurgitant lesions. The following article reviews the current role of CMR imaging in studying disease severity and myocardial remodeling in patients with VHD.

Stimulus-effect relations for left ventricular growth obtained with a simple multi-scale model: the influence of hemodynamic feedback

Cardiac growth is an important mechanism for the human body to respond to changes in blood flow demand. Being able to predict the development of chronic growth is clinically relevant, but so far models to predict growth have not reached consensus on the stimulus–effect relation. In a previously published study, we modeled cardiac and hemodynamic function through a lumped parameter approach. We evaluated cardiac growth in response to valve disease using various stimulus–effect relations and observed an unphysiological decline pump function. Here we extend that model with a model of hemodynamic feedback that maintains mean arterial pressure and cardiac output through adaptation of peripheral resistance and circulatory unstressed volume. With the combined model, we obtain stable growth and restoration of pump function for most growth laws. We conclude that a mixed combination of stress and strain stimuli to drive cardiac growth is most promising since it (1) reproduces clinical observations on cardiac growth well, (2) requires only a small, clinically realistic adaptation of the properties of the circulatory system and (3) is robust in the sense that results were fairly insensitive to the exact choice of the chosen mechanics loading measure. This finding may be used to guide the choice of growth laws in more complex finite element models of cardiac growth, suitable for predicting the response to spatially varying changes in tissue load. Eventually, the current model may form a basis for a tool to predict patient-specific growth in response to spatially homogeneous changes in tissue load, since it is computationally inexpensive.

Clinical Situations Associated with Inappropriately Large Regurgitant Volumes in the Assessment of Mitral Regurgitation Severity Using the Proximal Flow Convergence Method in Patients with Chordae Rupture

BACKGROUND

Regurgitant volume (RVol) calculated using the proximal flow convergence method (proximal isovelocity surface area [PISA]) has been accepted as a key quantitative parameter for the diagnosis of and clinical decision-making with regard to severe mitral regurgitation (MR). However, a recent prospective study showed a significant overestimation of RVol by the echocardiographic PISA method compared with the MR volume measured using magnetic resonance imaging. We aimed to evaluate the frequency of overestimation of RVol by the PISA method and the clinical conditions that require a different quantitative method to correct the overestimation.

METHODS

We retrospectively enrolled 166 consecutive patients with degenerative MR and chordae rupture, in whom RVol was measured using both the PISA and two-dimensional Doppler volumetric methods. The volumetric method was used to measure total stroke volume using the two-dimensional Simpson biplane method, and forward stroke volume was measured using pulsed Doppler tracing at the left ventricular (LV) outflow tract. RVol by the volumetric method was calculated using total stroke volume - forward stroke volume. Severe MR was defined as an RVol >60 mL.

RESULTS

All patients had severe MR based on RVol by the PISA method, but 68 (41.1%) showed RVol by the volumetric method values of <60 mL, resulting in discordant results. The patients with discordant results were characterized by a higher prevalence of female sex, lower body surface area, smaller LV diastolic and systolic dimensions and volumes, smaller left atrial volume, smaller PISA angle, and lower frequency of flail leaflets (39.7% vs 62.2%, P = .004). Multivariate analysis revealed that LV end-diastolic volume (LVEDV) and PISA angle were independent factors, with the best cutoff LVEDV and PISA angle being 173 mL and 103°, respectively. During follow-up (median, 3.4 years; interquartile range, 2.0-4.8 years), mitral valve repair and replacement were performed in 103 and six patients, respectively. The 2-year mitral valve surgery-free survival rate was higher in the discordant group (51.8% ± 0.06% vs 31.2% ± 0.05%, P < .001).

CONCLUSIONS

Even in the patients with documented chordae rupture, the PISA method alone resulted in inappropriate overestimation of MR severity in a significant proportion of patients. Thus, an additive quantitative method is absolutely necessary in patients with a small LVEDV or narrow PISA angle.

Evaluation of stimulus-effect relations in left ventricular growth using a simple multiscale model

Cardiac growth is the natural capability of the heart to change size in response to changes in blood flow demand of the growing body. Cardiac diseases can trigger the same process leading to an abnormal type of growth. Prediction of cardiac growth would be clinically valuable, but so far published models on cardiac growth differ with respect to the stimulus-effect relation and constraints used for maximum growth. In this study, we use a zero-dimensional, multiscale model of the left ventricle to evaluate cardiac growth in response to three valve diseases, aortic and mitral regurgitation along with aortic stenosis. We investigate how different combinations of stress- and strain-based stimuli affect growth in terms of cavity volume and wall volume and hemodynamic performance. All of our simulations are able to reach a converged state without any growth constraint, with the most promising results obtained while considering at least one stress-based stimulus. With this study, we demonstrate how a simple model of left ventricular mechanics can be used to have a first evaluation on a designed growth law.