Impact of Prosthesis-Patient Mismatch on Survival After Mitral Valve Replacement

Intravenous Levosimendan versus Inhalational Milrinone in the Management of Pulmonary Hypertension during Adult Cardiac Surgery: A Randomized Clinical Trial

Introduction: The perioperative management of patients with pulmonary hypertension (PH) undergoing cardiac surgery is challenging, mainly due to the potential risk of right ventricular failure (RVF). Levosimendan is a calcium-sensitizing agent that has primarily been used in the treatment of decompensated heart failure. However, recently levosimendan has been shown to be an effective and safe therapeutic strategy for patients with pulmonary arterial hypertension and PH associated with left heart disease. The aim of this study was to investigate the potential utility of the preemptive administration of levosimendan in cardiac surgical patients with preexisting PH and to compare its effectiveness with milrinone, which represents an already established therapeutic option in the management of PH during cardiac surgery. Materials and Methods: In this study, 40 adult cardiac surgical patients with PH were randomly assigned to receive either levosimendan intravenously or milrinone via inhalation in a double-blind fashion prior to a cardiopulmonary bypass (CPB). Hemodynamic and echocardiographic parameters were recorded and evaluated before and after the administration of the drugs. Results and Conclusions: The results of this study demonstrated that both levosimendan and milrinone administered before CPB in cardiac surgical patients with PH may offer protective benefits, reducing pulmonary artery pressure and preventing the exacerbation of PH and RVF. Pulmonary vasodilation attributed to levosimendan is of longer duration and greater magnitude compared to pulmonary vasodilation afforded by milrinone.

Monitoring of Levosimendan Administration in Patients with Pulmonary Hypertension Undergoing Cardiac Surgery and Effect of Two Different Dosing Schemes on Hemodynamic and Echocardiographic Parameters

INTRODUCTION

The perioperative management of patients with pulmonary hypertension (PH) undergoing cardiac surgery represents one of the most challenging clinical scenarios. This fact mainly depends on the relationship existing between PH and right ventricular failure (RVF). Levosimendan (LS) is an inodilator that might be an effective agent in the treatment of PH and RVF. The aim of this study was to examine the impact of the duration of cardiopulmonary bypass (CPB) on the therapeutic drug monitoring of LS and to evaluate the effect of preemptive administration of LS on perioperative hemodynamic and echocardiographic parameters in cardiac surgical patients with preexisting PH.

MATERIALS AND METHODS

In this study, LS was administered in adult patients undergoing cardiac surgery before CPB in order to prevent exacerbation of preexisting PH and subsequent right ventricular dysfunction. Thirty cardiac surgical patients with preoperatively confirmed PH were randomized to receive either 6 μg/kg or 12 μg/kg of LS after the induction of anesthesia. The plasma concentration of LS was measured after CPB. In this study, a low sample volume was used combined with a simple sample preparation protocol. The plasma sample was extracted by protein precipitation and evaporated; then, the analyte was reconstituted and detected using specific and sensitive bioanalytical liquid chromatography with mass spectrometry (LC-MS/MS) methodology. The clinical, hemodynamic, and echocardiographic parameters were registered and evaluated before and after the administration of the drug.

RESULTS

A fast bioanalytical LC-MS/MS methodology (a run time of 5.5 min) was developed for the simultaneous determination of LS and OR-1896, its main metabolite in human plasma. The LC-MS/MS method was linear over a range of 0.1-50 ng/mL for LS and 1-50 ng/mL for its metabolite OR-1896. Measured plasma concentrations of LS were inversely related to the duration of CPB. LS administration before CPB during cardiac surgery was effective in reducing pulmonary artery pressure and improving hemodynamic parameters after CPB, with a more pronounced and durable effect of the drug at the dose of 12 μg/kg. Additionally, administration of LS at a dose of 12 μg/kg in cardiac surgical patients with PH before CPB improved right ventricular function.

CONCLUSION

LS administration decreases pulmonary artery pressure and may improve right ventricular function in patients with PH undergoing cardiac surgery.

Pulmonary hypertension associated with cardiopulmonary bypass and cardiac surgery

BACKGROUND AND AIM

Pulmonary hypertension (PH) is frequently associated with cardiovascular surgery and is a common complication that has been observed after surgery utilizing cardiopulmonary bypass (CPB). The purpose of this review is to explain the characteristics of PH, the mechanisms of PH induced by cardiac surgery and CPB, treatments for postoperative PH, and future directions in treating PH induced by cardiac surgery and CPB using up-to-date findings.

METHODS

The PubMed database was utilized to find published articles.

RESULTS

There are many mechanisms that contribute to PH after cardiac surgery and CPB which involve pulmonary vasomotor dysfunction, cyclooxygenase, the thromboxane A2 and prostacyclin pathway, the nitric oxide pathway, inflammation, and oxidative stress. Furthermore, there are several effective treatments for postoperative PH within different types of cardiac surgery.

CONCLUSIONS

By possessing a deep understanding of the mechanisms that contribute to PH after cardiac surgery and CPB, researchers can develop treatments for clinicians to use which target the mechanisms of PH and ultimately reduce and/or eliminate postoperative PH. Additionally, learning about the most up-to-date studies regarding treatments can allow clinicians to choose the best treatments for patients who are undergoing cardiac surgery and CPB.

Standardized Definitions for Bioprosthetic Valve Dysfunction Following Aortic or Mitral Valve Replacement: JACC State-of-the-Art Review

Bioprosthetic valve dysfunction (BVD) and bioprosthetic valve failure (BVF) may be caused by structural or nonstructural valve dysfunction. Both surgical and transcatheter bioprosthetic valves have limited durability because of structural valve deterioration. The main objective of this summary of experts participating in a virtual workshop was to propose standardized definitions for nonstructural and structural BVD and BVF following aortic or mitral biological valve replacement with the goal of facilitating research reporting and implementation of these terms in clinical practice. Definitions of structural BVF, based on valve reintervention or death, underestimate the true incidence of BVF. However, definitions solely based on the presence of high transprosthetic gradient at a given echocardiogram during follow-up overestimate the incidence of structural BVD and BVF. Definitions of aortic or mitral structural BVD must therefore include the confirmation by imaging of permanent structural changes to the leaflets alongside evidence of deterioration in valve hemodynamic function at echocardiography follow-up.

Hybrid Surgery for Severe Mitral Valve Calcification: Limitations and Caveats for an Open Transcatheter Approach

Background and Objectives: Mitral stenosis with extensive mitral annular calcification (MAC) remains surgically challenging in respect to clinical outcome. Prolonged surgery time with imminent ventricular rupture and systolic anterior motion can be considered as a complex of causal factors. The aim of our alternative hybrid approach was to reduce the risk of annual rupture and paravalvular leaks and to avoid obstruction of the outflow tract. A review of the current literature was also carried out. Materials and Methods: Six female patients (mean age 76 ± 9 years) with severe mitral valve stenosis and severely calcified annulus underwent an open implantation of an Edwards Sapien 3 prosthesis on cardiopulmonary bypass. Our hybrid approach involved resection of the anterior mitral leaflet, placement of anchor sutures and the deployment of a balloon expanded prosthesis under visual control. Concomitant procedures were carried out in three patients. Results: The mean duration of cross-clamping was 95 ± 31 min and cardiopulmonary bypass was 137 ± 60 min. The perioperative TEE showed in three patients an inconspicuous, heart valve-typical gradient on all implanted prostheses and a clinically irrelevant paravalvular leakage occurred in the anterior annulus. In the left ventricular outflow tract, mild to moderately elevated gradients were recorded. No adverse cerebrovascular events and pacemaker implantations were observed. All but one patient survived to discharge. Survival at one year was 83.3%. Conclusions: This "off label" implantation of the Edwards Sapien 3 prosthesis may be considered as a suitable bail-out approach for patients at high-risk for mitral valve surgery or deemed inoperable due to extensive MAC.

Impact of prosthesis-patient mismatch on late outcomes after bioprosthetic mitral valve replacement for mitral regurgitation

Negative impact of prosthesis-patient mismatch on long-term survival after valve replacement has been reported. However, the effect of prosthesis-patient mismatch after bioprosthetic mitral valve replacement has not yet been well examined. The purpose of this study was to investigate the effect of prosthesis-patient mismatch on late outcomes after bioprosthetic mitral valve replacement for mitral regurgitation. A total of 181 patients underwent bioprosthetic mitral valve replacement between April 2008 and December 2016. After excluding patients with mitral stenosis and those with incomplete data, 128 patients were included in the study. Postoperative transthoracic echocardiography was performed before discharge for all patients and the effective orifice area of bioprosthetic mitral valve was calculated using the formula: 220/pressure half-time, and the effective orifice area index was calculated by the formula: effective orifice area/body surface area. Prosthesis-patient mismatch was defined as a postoperative effective orifice area index ≤ 1.2 cm²/m². The characteristics and outcomes were compared between the groups. There were 34 patients (26.6%) with prosthesis-patient mismatch and 94 patients (73.4%) without prosthesis-patient mismatch. There were no significant differences in the in-hospital mortality and morbidities. Multivariable analysis showed that prosthesis-patient mismatch was an independent predictor of late mortality (hazard ratio 3.38; 95% confidence interval 1.69-6.75; p = 0.001) and death from heart failure (hazard ratio 31.03, 95% confidence interval 4.49-214.40, p < 0.001). Prosthesis-patient mismatch at discharge after mitral valve replacement for mitral regurgitation was associated with long-term mortality and death from heart failure.

Pulmonary Hypertension in Heart Failure

Pulmonary hypertension (PH) is traditionally defined as a mean pulmonary arterial pressure (mPAP) ≥25 mmHg. Although various factors cause PH, the most common etiology is PH due to left heart disease (PH-LHD). The underlying LHD is characterized by heart failure (HF) with reduced ejection fraction (HFrEF), HF with preserved ejection fraction (HFpEF), valvular heart disease, cardiomyopathies, or arrhythmic diseases. Regardless of its underlying cause, elevated left atrial (LA) filling pressure is a manifestation of advanced heart disease. High LA pressure then causes persistent backflow to the pulmonary veins, which increases mPAP. PH-LHD at this stage is named isolated postcapillary PH (IpcPH). Further progression of IpcPH is associated with pulmonary vasculature remodeling and hypertrophy, which consists of adding the precapillary component of PH to the pre-existing postcapillary PH. This form of PH-LHD is called combined precapillary and postcapillary PH (CpcPH). To date, therapeutic strategies for PH-LHD have been investigated in the context of HFrEF or HFpEF. Pulmonary arterial hypertension (PAH)-specific drugs have been tested in HFrEF and HFpEF populations, although encouraging results have not been demonstrated. As PAH-specific drugs target the precapillary component of PH-LHD, future studies utilizing such therapeutics in PH-LHD patients with CpcPH appear to have a more robust pathobiological basis. This article reviews the diagnosis, pathophysiology, treatment, and future direction of PH in HF.

Computational investigation of left ventricular hemodynamics following bioprosthetic aortic and mitral valve replacement

The left ventricle of the heart is a fundamental structure in the human cardiac system that pumps oxygenated blood into the systemic circulation. Several valvular conditions can cause the aortic and mitral valves associated with the left ventricle to become severely diseased and require replacement. However, the clinical outcomes of such operations, specifically the postoperative ventricular hemodynamics of replacing both valves, are not well understood. This work uses computational fluid-structure interaction (FSI) to develop an improved understanding of this effect by modeling a left ventricle with the aortic and mitral valves replaced with bioprostheses. We use a hybrid Arbitrary Lagrangian-Eulerian/immersogeometric framework to accommodate the analysis of cardiac hemodynamics and heart valve structural mechanics in a moving fluid domain. The motion of the endocardium is obtained from a cardiac biomechanics simulation and provided as an input to the proposed numerical framework. The results from the simulations in this work indicate that the replacement of the native mitral valve with a tri-radially symmetric bioprosthesis dramatically changes the ventricular hemodynamics. Most significantly, the vortical motion in the left ventricle is found to reverse direction after mitral valve replacement. This study demonstrates that the proposed computational FSI framework is capable of simulating complex multiphysics problems and can provide an in-depth understanding of the cardiac mechanics.

Persistent Pulmonary Hypertension in Corrected Valvular Heart Disease: Hemodynamic Insights and Long-Term Survival

Background The determinants and consequences of pulmonary hypertension after successfully corrected valvular heart disease remain poorly understood. We aim to clarify the hemodynamic bases and risk factors for mortality in patients with this condition. Methods and Results We analyzed long-term follow-up data of 222 patients with pulmonary hypertension and valvular heart disease successfully corrected at least 1 year before enrollment who had undergone comprehensive hemodynamic and imaging characterization as per the SIOVAC (Sildenafil for Improving Outcomes After Valvular Correction) clinical trial. Median (interquartile range) mean pulmonary pressure was 37 mm Hg (32-44 mm Hg) and pulmonary artery wedge pressure was 23 mm Hg (18-26 mm Hg). Most patients were classified either as having combined precapillary and postcapillary or isolated postcapillary pulmonary hypertension. After a median follow-up of 4.5 years, 91 deaths accounted for 4.21 higher-than-expected mortality in the age-matched population. Risk factors for mortality were male sex, older age, diabetes mellitus, World Health Organization functional class III and higher pulmonary vascular resistance-either measured by catheterization or approximated from ultrasound data. Higher pulmonary vascular resistance was related to diabetes mellitus and smaller residual aortic and mitral valve areas. In turn, the latter correlated with prosthetic nominal size. Six-month changes in the composite clinical score and in the 6-minute walk test distance were related to survival. Conclusions Persistent valvular heart disease-pulmonary hypertension is an ominous disease that is almost universally associated with elevated pulmonary artery wedge pressure. Pulmonary vascular resistance is a major determinant of mortality in this condition and is related to diabetes mellitus and the residual effective area of the corrected valve. These findings have important implications for individualizing valve correction procedures. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00862043.

Prosthesis-patient mismatch after mitral valve replacement: A pooled meta-analysis of Kaplan-Meier-derived individual patient data

Objective

The hemodynamic effect and early and late survival impact of prosthesis–patient mismatch (PPM) after mitral valve replacement remains insufficiently explored.

Methods

Pubmed, Embase, Web of Science, and Cochrane Library databases were searched for English language original publications. The search yielded 791 potentially relevant studies. The final review and analysis included 19 studies compromising 11,675 patients.

Results

Prosthetic effective orifice area was calculated with the continuity equation method in 7 (37%), pressure half‐time method in 2 (10%), and partially or fully obtained from referenced values in 10 (53%) studies. Risk factors for PPM included gender (male), diabetes mellitus, chronic renal disease, and the use of bioprostheses. When pooling unadjusted data, PPM was associated with higher perioperative (odds ratio [OR]: 1.66; 95% confidence interval [CI]: 1.32–2.10; p < .001) and late mortality (hazard ratio [HR]: 1.46; 95% CI: 1.21–1.77; p < .001). Moreover, PPM was associated with higher late mortality when Cox proportional‐hazards regression (HR: 1.97; 95% CI: 1.57–2.47; p < .001) and propensity score (HR: 1.99; 95% CI: 1.34–2.95; p < .001) adjusted data were pooled. Contrarily, moderate (HR: 1.01; 95% CI: 0.84–1.22; p = .88) or severe (HR: 1.19; 95% CI: 0.89–1.58; p = .24) PPM were not related to higher late mortality when adjusted data were pooled individually. PPM was associated with higher systolic pulmonary pressures (mean difference: 7.88 mmHg; 95% CI: 4.72–11.05; p < .001) and less pulmonary hypertension regression (OR: 5.78; 95% CI: 3.33–10.05; p < .001) late after surgery.

Conclusions

Mitral valve PPM is associated with higher postoperative pulmonary artery pressure and might impair perioperative and overall survival. The relation should be further assessed in properly designed studies.

Weight gain potential-a neglected entity during valve replacement

Introduction

During valve replacement, appropriate valve size will be chosen based on many factors, neglecting the potential of the patient for gaining weight. We aimed at evaluating the weight gain potential and its effect on hemodynamics in post mitral valve replacement (MVR) patients.

Material and methods

In 118 post-MVR patients, demographic and echocardiographic data at the time of discharge and follow-up were obtained and analyzed. Primary aim of study is to analyze the hemodynamics of patients based on weight gain/loss. Secondary aim is to evaluate the same in patient-prosthesis mismatch (PPM) subgroup and to evaluate the study population for the potential to gain/loss weight.

Results

Among 118 patients, 87 patients (73.7%) gained weight. In 87 weight gained patients, left atrial (LA) size (p = 0.011) and pulmonary artery systolic (PA) pressure (p = 0.028) at follow-up were significantly elevated than the discharge values. Among 53 PPM patients (incidence, 44.9%), 34 patients gained weight and their PA pressure was found to be elevated at follow-up (p = 0.021) whereas weight lost group does not show any significant difference (p = 0.972). Frequency of weight gain was more among patients who weighed < 50 kg preoperatively (28 out of 30) (p = 0.013) and 20 to 30 years age group patients (p = 0.043). No sex predilection was noted (p = 0.149).

Conclusion

In post-MVR patients, weight gain has definitive influence over hemodynamics. In PPM subgroup, weight gained patients had significantly increased PA systolic pressure at follow-up. Young, < 50 kg weighed, and PPM patients should be advised to maintain their weight post MVR for better hemodynamics.

Impact of prosthesis-patient mismatch on early and late outcomes after mitral valve replacement: a meta-analysis

Background

Prognostic significance of prosthesis-patient mismatch (PPM) after mitral valve replacement (MVR) remains uncertain because of the limited studies reporting inconsistent or even contrary results. This meta-analysis pooled results of all available studies comparing early and late prognoses between patients with significant mitral PPM and those without.

Methods

Studies were identified by searching Pubmed, Excerpta Medica Database, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. Impact of PPM on postoperative hemodynamic results, thirty-day mortality, overall mortality, mortality of thirty-day survivors, and primary morbidity after MVR was evaluated via meta-analysis. Robustness of pooled estimates, source of heterogeneity, and publication bias were assessed via sensitivity analyses, meta-regression as well as subgroup analysis stratified according to methodological or clinical heterogeneity, or sequential omission method, and funnel plot or Begg's and Egger's tests, respectively.

Results

Nineteen cohort studies involving 9302 individuals (PPM group: n = 5109, Control group: n = 4193) were included for meta-analysis. Total PPM and severe PPM prevalence were 3.8%-85.9% and 1%-27%, with a mean value of 54.9% and 14.1%, respectively. As compared with control group, mitral PPM group demonstrated a poorer postoperative hemodynamic status of higher mean and peak residual transprosthetic pressure gradients (TPG), higher postoperative systolic pulmonary artery pressure (SPAP) and less reduction, higher postoperative pulmonary hypertension (PH) prevalence and less PH regression, smaller net atrioventricular compliance, less NYHA class decrease, higher postoperative functional tricuspid regurgitation prevalence and less regression. The PPM group also revealed a higher thirty-day mortality, long-term overall mortality, mortality of thirty-day survivors, and postoperative congestive heart failure prevalence, which were positively correlated with the severity of PPM if it was classified into tri-level subgroups. Left ventricular end-diastolic diameter, postoperative atrial fibrillation (AF) prevalence, and the AF regression were analogous between groups. Most pooled estimates were robust according to sensitivity analyses. Male patients and bioprosthesis implantation proportion were prominent source of between-study heterogeneity on thirty-day mortality. Publication bias was not significant in tests for all the outcomes, except for SPAP and TPG.

Conclusions

Mitral PPM would result in poorer postoperative hemodynamics and worse early and late prognosis. Severe PPM must be avoided since deleterious impact of mitral PPM was severity dependent.

Impact of Prosthesis-Patient Mismatch After Mitral Valve Replacement: A Propensity Score Analysis

The effect of patient-prosthesis mismatch (PPM) on late outcomes after mitral valve replacement (MVR) remains unclear. We evaluated the impact of PPM after MVR on the late survival using propensity score matching analysis. From 2007 to 2018, 660 consecutive MVRs were performed. Effective orifice areas were obtained from a literature review of in vivo echocardiographic data, and mitral PPM was defined as an effective orifice area index of ≤1.2 cm²/m². Propensity score matching yielded a cohort of 126 patients with PPM and 126 patients without PPM. Mitral PPM was found in 37.8% of the patients. In the whole matched patients, there were no differences in late survival (log-rank test, P = 0.629) between 2 groups. Patients aged ≤70 years and those aged >70 years had no differences in late survival (log-rank test, P = 0.073 and 0.572). The Cox proportional hazards model for the overall survival showed that mitral PPM tended to decrease survival in patients aged ≤70 years (P = 0.084, hazard ratio [HR] 2.647, 95% CI: 0.876-7.994). Mitral PPM did not adversely affect long-term survival. There may be a tendency of adverse impact on late survival in patients aged ≤70 years. Implanting a safe size rather than larger size prosthesis in mitral position may be an appropriate option in older patients.

Mitral prosthetic size predictor in minimally invasive mitral valve replacement

Background

Minimally invasive mitral valve replacement has become popular across the world. However, annular rupture and patient – prosthetic mismatch (PPM) are still problematic, particularly in the Asian population. To avoid this, a predictor model could be beneficial. Our study aimed to assess the value of mitral valve diameters measured on TTE and CT scan on predicting the actual mitral prostheses.

Methods

From January 2018 to December 2019, a total number of 96 patients underwent minimally invasive mitral valve replacement. The association between imaging measurements and the outcome was checked by scatter plot and Pearson’s correlation coefficient. Univariable linear regression was used to build the prediction model.

Results

The three strongest correlations for the whole population are the following features: Mean TTE diameter (0.702), mean diameter on CT lowest plane through the mitral annulus (0.679), and area-derived diameter on CT highest plane through the mitral annulus (0.665). The prosthetic size of the tissue valve group was more correlated to the calculated annulus diameters than that of the mechanical valve group. Tissue valve size predictor models based on these calculated diameters were 16.19 + 0.27 × d (r = 0.744), 12.74 + 0.44 × d (r = 0.756) and 12.79 + 0.38 × d (r = 0.730), respectively.

Conclusion

Mitral prosthetic size could be predicted based on the mitral diameters measured on TTE and CT scan. The overall correlation coefficient varied from 0.665 (CT Scan) to 0.702 (TTE). These models performed better when applied to bioprosthesis.

Clinical outcomes and hemodynamic performance of Dafodil™ aortic and mitral pericardial bioprosthesis: 1-year results from Dafodil-1 first-in-human trial

BACKGROUND

Bioprosthesis has been increasingly implanted for the treatment of transvalvular disease across the world. A new Dafodil™ pericardial bioprosthesis (Meril Life Sciences Pvt. Ltd., India) recently approved by Conformité Européenne (CE) is a tri-leaflet, stented, bovine valve. The purpose of Dafodil-1 first-in-human trial was to evaluate clinical safety and performance (including hemodynamic parameters) of the Dafodil pericardial bioprosthesis in patients who underwent aortic or mitral valve replacement.

METHODS

This prospective, multicenter clinical trial enrolled 60 patients (Aortic: 30 patients; Mitral: 30 patients) from seven sites across India. Safety endpoints were early (≤30 days) and late (> 30 days) mortality and valve-related morbidity. The performance endpoints were hemodynamic performance, improvement in NYHA functional class, and change in the quality of life using SF-12v1 health survey.

RESULTS

From July 2017 to July 2018, 60 patients underwent implantation of the Dafodil pericardial bioprosthesis. Post-operatively, NYHA functional class significantly improved in all the patients (Aortic: 90% NYHA class-I and 10% NYHA class-II; Mitral: 96.55% NYHA class-I and 3.45% NYHA class-II; P < 0.001). There was no death in aortic valve replacement patients till 12-month. In mitral valve replacement patients, early mortalities occurred in three patients, and late mortality occurred in one patient; none of these were valve-related. Freedom from all-cause mortality reported was 93.33% at 12-month. Mean aortic pressure gradient decreased from 52.71 ± 24.47 mmHg [with 0.89 ± 0.70 cm² effective orifice area (EOA)] pre-operatively to 14.49 ± 6.58 mmHg (EOA: 1.85 ± 0.27 cm²) at 12-month. Overall, the mitral mean pressure gradient and EOA were 4.41 ± 1.69 mmHg and 2.67 ± 0.48 cm², respectively, at 12-month. Significant improvement (P < 0.05) in the patients' quality of life was reported at all follow-ups.

CONCLUSIONS

The clinical safety and performance of the Dafodil pericardial bioprosthesis were favourable at 12-month. Moreover, a study with a larger patient population and longer follow-up is warranted to further assess the device.

TRIAL REGISTRATION

Dafodil-1 trial has been prospectively registered on 10/07/2017 under Clinical Trial Registry-India (http://www.ctri.nic.in). (Registration number: CTRI/2017/07/009008).

The effect of patient-prosthesis mismatch on survival after aortic and mitral valve replacement: a 10 year, single institution experience

Background

The evidence on the impact of patient-prosthesis Mismatch (PPM) on survival thus far has been conflicting. The aim of this study was to 1) study the effect of PPM on survival after isolated aortic and mitral valve replacement and 2) Assess the interaction between left ventricular function and PPM on survival.

Methods

The study cohort was patients who underwent isolated Aortic valve replacement (AVR) and Mitral valve replacement (MVR) over a 10-year period from 2008 to 2018. PPM was defined using the projected indexed effective orifice area (EOAi). The cohort was divided into different groups based on the degree of PPM. The severity of PPM was classified using threshold values of EOAi used in the literature. The Kaplan- Meier method was used to compare survival by degree of PPM. Multivariate Cox proportional hazards models were used to generate adjusted hazard ratios (HR) with 95% confidence intervals. An interactive term for ejection fraction (EF) was added to test whether EF modifies the effect of the PPM grade on survival. In addition, sub-group analysis based on left ventricular function was performed.

Results

In the AVR cohort, there were a total of 1953 patients. The distribution of patients in the different PPM categories was as follows: no PPM 59.7%; moderate PPM 36.8%; severe PPM 3.5%. There was no significant difference in survival between the different groups. At 10 years, the adjusted HR between patients with severe PPM versus no PPM was 1.1(CI 0.5–2.4, p >  0.05) and the HR between those with moderate PPM versus no PPM was 0.97 (CI 0.74–1.23, p >  0.05). In the MVR cohort, there were a total of 298 patients. The distribution of PPM is as follows: no PPM 59.4%; and with PPM 40.6%. Again, there was no significant difference in survival between the groups. At 5 years, the adjusted HR between patients with PPM versus no PPM was 1.45 (CI 0.67–3.14, p >  0.05). In both groups, there was no significant interaction between left ventricular function (LVF) and degree of PPM on survival.

Conclusions

In our study cohort, the degree of PPM was not an independent predictor of survival after AVR or MVR. There was also no significant interaction between LV function and degree of PPM on survival.

Sildenafil for improving outcomes in patients with corrected valvular heart disease and persistent pulmonary hypertension: a multicenter, double-blind, randomized clinical trial

Aims

We aimed to determine whether treatment with sildenafil improves outcomes of patients with persistent pulmonary hypertension (PH) after correction of valvular heart disease (VHD).

Methods and results

The sildenafil for improving outcomes after valvular correction (SIOVAC) study was a multricentric, randomized, parallel, and placebo-controlled trial that enrolled stable adults with mean pulmonary artery pressure ≥ 30 mmHg who had undergone a successful valve replacement or repair procedure at least 1 year before inclusion. We assigned 200 patients to receive sildenafil (40 mg three times daily, n = 104) or placebo (n = 96) for 6 months. The primary endpoint was the composite clinical score combining death, hospital admission for heart failure (HF), change in functional class, and patient global self-assessment. Only 27 patients receiving sildenafil improved their composite clinical score, as compared with 44 patients receiving placebo; in contrast 33 patients in the sildenafil group worsened their composite score, as compared with 14 in the placebo group [odds ratio 0.39; 95% confidence interval (CI) 0.22–0.67; P < 0.001]. The Kaplan–Meier estimates for survival without admission due to HF were 0.76 and 0.86 in the sildenafil and placebo groups, respectively (hazard ratio 2.0, 95% CI = 1.0–4.0; log-rank P = 0.044). Changes in 6-min walk test distance, natriuretic peptides, and Doppler-derived systolic pulmonary pressure were similar in both groups.

Conclusion

Treatment with sildenafil in patients with persistent PH after successfully corrected VHD is associated to worse clinical outcomes than placebo. Off-label usage of sildenafil for treating this source of left heart disease PH should be avoided.

The trial is registered with ClinicalTrials.gov, number NCT00862043.

Incidence and predictors of mismatch after mechanical mitral valve replacement

Background

Patient-prosthesis mismatch after mitral valve replacement has an unfavorable postoperative hemodynamic outcome, which underlines the importance of identifying and preventing prosthesis- and patient-related risk factors. This study was conducted to determine the incidence and identify possible predictors of patient-prosthesis mismatch.

Methods

A prospective study was conducted on 715 patients with a mean age of 42 ± 11 years who underwent mechanical mitral valve replacement between 2013 and 2017. The effective orifice area of the prostheses was estimated by the continuity equation, and a mismatch was defined as an effective orifice area index ≤1.2 cm2·m−2. The mean clinical and echocardiographic follow-up was 26.74 ± 11.58 months. Multivariate regression analysis was performed to identify predictors of patient-prosthesis mismatch.

Results

Patient-prosthesis mismatch was detected in 382 (53.4%) patients. A small mechanical prosthesis (<27 mm) was inserted in 54.3%. Mortality during follow-up was 9% (65 patients). Patient-prosthesis mismatch was identified in patients with preoperative rheumatic mitral valve pathology, associated tricuspid regurgitation, higher New York Heart Association class, preoperative atrial fibrillation, mitral stenosis, and small preoperative left ventricular dimensions. Multivariate analysis identified mitral stenosis, preoperative atrial fibrillation, and small postoperative left ventricular end-diastolic dimension as risk factors for patient-prosthesis mismatch.

Conclusion

Patient-prosthesis mismatch is a common sequela after mechanical mitral valve replacement. Identification of predictors of patient-prosthesis mismatch can help so that a preoperative strategy can be implemented to avoid its occurrence.

Prosthesis-Patient Mismatch Negatively Affects Outcomes after Mitral Valve Replacement: Meta-Analysis of 10,239 Patients

OBJECTIVE

This study sought to evaluate the impact of prosthesis-patient mismatch on the risk of perioperative and long-term mortality after mitral valve replacement.

METHODS

Databases were researched for studies published until December 2018. Main outcomes of interest were perioperative and 10-year mortality and echocardiographic parameters.

RESULTS

The research yielded 2,985 studies for inclusion. Of these, 16 articles were analyzed, and their data extracted. The total number of patients included was 10,239, who underwent mitral valve replacement. The incidence of prosthesis-patient mismatch after mitral valve replacement was 53.7% (5,499 with prosthesis-patient mismatch and 4,740 without prosthesis-patient mismatch). Perioperative (OR 1.519; 95%CI 1.194-1.931, P<0.001) and 10-year (OR 1.515; 95%CI 1.280-1.795, P<0.001) mortality was increased in patients with prosthesis-patient mismatch. Patients with prosthesis-patient mismatch after mitral valve replacement had higher systolic pulmonary artery pressure and transprosthethic gradient and lower indexed effective orifice area and left ventricle ejection fraction.

CONCLUSION

Prosthesis-patient mismatch increases perioperative and long-term mortality. Prosthesis-patient mismatch is also associated with pulmonary hypertension and depressed left ventricle systolic function. The findings of this study support the implementation of surgical strategies to prevent prosthesis-patient mismatch in order to decrease mortality rates.

Prosthesis-patient mismatch after mitral valve replacement: a single-centered retrospective analysis in East China

Background

Prosthesis–patient mismatch (PPM) may affect the clinical outcomes of patients undergoing mitral valve replacement (MVR) surgery. We aimed to investigate the incidence of PPM of the mitral position in our center and analyze the possible predictors of PPM as well as its effect on short-term outcomes.

Methods

We retrospectively examined all consecutive patients with isolated or concomitant MVR at our center from 2013 to 2015. PPM was defined as an indexed effective orifice area (iEOA) of ≤1.2 cm2/m2. After inclusion and exclusion, a total of 1067 patients were analyzed. The baseline information were collected and compared between the two groups. Multivariate logistic regression analysis was conducted to determine the preoperative predictors of PPM as well as the effect of PPM on early mortality.

Results

A total of 1067 patients were included in the study. PPM was detected in 15.9% of the patients while 12 patients (1.12%) met the criteria for severe PPM. Patients with PPM compared to the non-PPM patients had higher age, larger body surface area and were more likely to be male and obese. Logistic regression analysis showed that higher age, larger BSA, bioprosthesis and smaller left ventricle end-diastolic diameter were predictors of PPM. There were no significant differences between the PPM and non-PPM groups regarding post-operative complications. Logistic regression analysis showed that PPM was not a risk factor of short-term mortality (P = 0.654). Also, there were no significant differences regarding short−/mid-term heart function between the PPM and non PPM groups (P = 0.902).

Conclusions

Our results demonstrated that higher age, bioprosthesis, larger BSA and smaller left ventricle size were associated with mitral PPM. However, PPM was not associated with poorer early outcomes after MVR surgery. In eastern of China, the prevalence of mitral valve stenosis is high; therefore, whether the standard PPM criteria are suitable for patients of this district needs to be further verified.

Effect of prosthesis patient mismatch in mitral position on pulmonary hypertension

OBJECTIVES

Pulmonary arterial hypertension (PAH) is associated with poor outcome after mitral valve replacement (MVR). We proposed to evaluate the effect of valve prosthesis patient mismatch (PPM) on pulmonary arterial (PA) pressure following MVR.

METHODS

Five hundred patients who have undergone MVR were studied retrospectively. Postoperative PA systolic pressure (PASP) measured 6 months postoperatively by Doppler echocardiography was compared with preoperative values. PASP ≥ 40 mmHg was defined as PAH. Mitral valve effective orifice area was calculated by the continuity equation and indexed for body surface area. PPM was defined as indexed effective orifice area ≤ 1.2 cm2/m2. A multivariate model was constructed to ascertain the independent determinants of systolic PA pressure. Also, a propensity score model was constructed to overcome the baseline differences between the PPM and no PPM groups.

RESULTS

The incidence of PPM in this study was 37.2%. The average postoperative PASPs were 30.49 and 42.35 mmHg in the no PPM and PPM groups, respectively; (P < 0.001). Regression of PAH in the PPM and no PPM groups was 76.26% and 20.64%, respectively; (P < 0.001). The indexed effective orifice area correlated well with postoperative PASP (r = 0.71). The overall survival and freedom from cardiac death at 10 years were 79.8% and 85.3%; and at 20 years were 66.5% and 74.3%, respectively. Both, overall survival and the freedom from cardiac death were higher in the no PPM group than in the PPM group; (P < 0.001). Propensity score matching analysis yielded 112 pairs of the PPM and no PPM cohorts, which revealed higher overall survival and freedom from cardiac death in the no PPM group; (P = 0.028 and 0.012, respectively).

CONCLUSIONS

Mitral PPM is an independent predictor of persistent PAH after MVR along with associated morbidity and reduced survival.

Transcatheter Mitral Valve Replacement: Functional Requirements for Device Design, Bench-Top, and Pre-Clinical Evaluation

Transcatheter Mitral Valve Replacement (TMVR) is currently under clinical investigation as a viable treatment option for mitral regurgitation (MR). Therefore, it is important to outline the key functional requirements of a TMVR prosthesis in order to provide an overall approach to assessing mitral valve replacement devices utilizing a combination of in vitro and preclinical methods. This article provides a review of the mitral valve disease as well as general considerations and guidance for developing a TMVR device based on International Industry Standards. Specific details pertaining to the mitral valve apparatus, morphology of mitral valve disease, assessment of specific patient population as well as hazard analysis to evaluate and develop a TMVR device to treat a specific patient population have been included. The details contained within this report are not all inclusive or explicate for every technology being developed but rather thought of as a general guide on how a TMVR technology could be developed in alignment with International Industry Standards. Key learnings from the Transcatheter Aortic Valve Replacement (TAVR) experience has also been considered and taken into account when outlining this general guidance for TMVR. Key learning points from the TAVR development experience included the following: quantification of acceptable levels of paravalvular leak, valve migration potential using various anchoring methods and overall implant frame failure modes when treating the native aortic valve. It should be noted that TAVR is over a decade further along in development and clinical experience compared to TMVR. These key learnings from the early experience with TAVR should be considered with all transcatheter development projects.

Exercise Hemodynamic and Functional Capacity After Mitral Valve Replacement in Patients With Ischemic Mitral Regurgitation

Background

In patients with ischemic mitral regurgitation requiring mitral valve replacement (MVR), the choice of the prosthesis type is crucial. The exercise hemodynamic and functional capacity performance in patients with contemporary prostheses have never been investigated. To compare exercise hemodynamic and functional capacity between biological (MVRb) and mechanical (MVRm) prostheses.

Methods and Results

We analyzed 86 consecutive patients with ischemic mitral regurgitation who underwent MVRb (n=41) or MVRm (n=45) and coronary artery bypass grafting. All patients underwent preoperative resting echocardiography and 6-minute walking test. At follow-up, exercise stress echocardiography was performed, and the 6-minute walking test was repeated. Resting and exercise indexed effective orifice areas of MVRm were larger when compared with MVRb (resting: 1.30±0.2 versus 1.19±0.3 cm 2 /m 2 ; P =0.03; exercise: 1.57±0.2 versus 1.18±0.3 cm 2 /m 2 ; P =0.0001). The MVRm had lower exercise systolic pulmonary arterial pressure at follow-up compared with MVRb (41±5 versus 59±7 mm Hg; P =0.0001). Six-minute walking test distance was improved in the MVRm (pre-operative: 242±43, post-operative: 290±50 m; P =0.001), whereas it remained similar in the MVRb (pre-operative: 250±40, post-operative: 220±44 m; P =0.13). In multivariable analysis, type of prosthesis, exercise indexed effective orifice area, and systolic pulmonary arterial pressure were joint predictors of change in 6-minute walking test (ie, difference between baseline and follow-up).

Conclusions

In patients with ischemic mitral regurgitation, bioprostheses are associated with worse hemodynamic performance and reduced functional capacity, when compared with MVRm. Randomized studies with longer follow-up including quality of life and survival data are required to confirm these results.

Usefulness of Mitral Valve Prosthetic or Bioprosthetic Time Velocity Index Ratio to Detect Prosthetic or Bioprosthetic Mitral Valve Dysfunction

This study aimed to investigate the utility of transthoracic echocardiographic (TTE) Doppler-derived parameters in detection of mitral prosthetic dysfunction and to define optimal cut-off values for identification of such dysfunction by valve type. In total, 971 TTE studies (647 mechanical prostheses; 324 bioprostheses) were compared with transesophageal echocardiography for evaluation of mitral prosthesis function. Among all prostheses, mitral valve prosthesis (MVP) ratio (ratio of time velocity integral of MVP to that of left ventricular outflow tract; odds ratio [OR] 10.34, 95% confidence interval [95% CI] 6.43 to 16.61, p<0.001), E velocity (OR 3.23, 95% CI 1.61 to 6.47, p<0.001), and mean gradient (OR 1.13, 95% CI 1.02 to 1.25, p=0.02) provided good discrimination of clinically normal and clinically abnormal prostheses. Optimal cut-off values by receiver operating characteristic analysis for differentiating clinically normal and abnormal prostheses varied by prosthesis type. Combining MVP ratio and E velocity improved specificity (92%) and positive predictive value (65%) compared with either parameter alone, with minimal decline in negative predictive value (92%). Pressure halftime (OR 0.99, 95% CI 0.98 to 1.00, p=0.04) did not differentiate between clinically normal and clinically abnormal prostheses but was useful in discriminating obstructed from normal and regurgitant prostheses. In conclusion, cut-off values for TTE-derived Doppler parameters of MVP function were specific to prosthesis type and carried high sensitivity and specificity for identifying prosthetic valve dysfunction. MVP ratio was the best predictor of prosthetic dysfunction and, combined with E velocity, provided a useful parameter for determining likelihood of dysfunction and need for further assessment.

Impact of prosthesis-patient mismatch after mitral valve replacement in rheumatic population: Does mitral position prosthesis-patient mismatch really exist?

Background

Prosthesis-patient mismatch (PPM) is characterised by the effects of inadequate prosthesis size relative to body surface area (BSA).The purpose of this study was to determine the impact of PPM on late clinical outcomes after mitral valve replacement (MVR) in rheumatic population.

Methods

From 2000 to 2013, a total of 445 patients (mean age 54.2 ± 11.7 years) underwent isolated MVR (±tricuspid annuloplasty) for rheumatic disease were investigated. Effective orifice area (EOA) was determined by the continuity equation and PPM was defined as indexed EOA (EOA/BSA) ≤ 1.2 cm²/m². Clinical and echocardiographic follow-up (mean follow up 8.7 ± 4.0 years) results were compared.

Results

37% of patients (n = 165) had PPM. There were no significant differences in baseline and operative characteristics between patients with and without PPM except age and IEOA. A significant decrease in mean trans-valvular pressure gradient (MPG) over time following MVR, however the change of MPG showed no differences between groups (No PPM vs. PPM: 8.9 ± 4.7 mmHg → 3.6 ± 1.2 mmHg vs. 8.7 ± 4.5 mmHg → 3.8 ± 1.4 mmHg, p-value = 0.28). In all patients, there was a reduction of left atrium dimension (58.6 ± 12.0 mm → 53.2 ± 12.0 mm vs. 57.9 ± 8.9 mm → 52.2 ± 8.9 mm, p-value = 0.68) and left ventricular end diastolic diameter (49.9 ± 5.7 mm → 48.9 ± 5.7 mm vs. 49.7 ± 6.0 mm → 48.3 ± 5.0 mm, p = 0.24) without statistical significance. Freedom from TR progression rates at 3 and 5 years (99% vs.98%, 99% vs. 98%, p-value = 0.1), and overall survival rates at 3 and 5 years (97% vs. 96%, 94% vs. 94%, p-value = 0.7) were similar.

Conclusion

This study shows that mitral PPM is not associated with atrial /ventricular remodeling and might not influence late clinical outcome including late TR progression, survival in rheumatic population.

Mitral implant of the Inovare transcatheter heart valve in failed surgical bioprostheses: a novel alternative for valve-in-valve procedures

Objectives

Reoperative procedure for the treatment of a failed mitral bioprosthesis is associated with considerable risk. In some cases, mortality is high and might contraindicate the benefit of the procedure. The minimally invasive valve-in-valve (ViV) transcatheter mitral valve implant offers an alternative less-invasive approach, reducing morbidity and mortality. The objective of this paper was to evaluate the mitral ViV approach using the Braile Inovare prosthesis.

Methods

The transcatheter balloon-expandable Braile Inovare prosthesis was used in 12 cases. Procedures were performed in a hybrid operating room, under fluoroscopic and echocardiographic control. Through left minithoracotomy, the prostheses were implanted through the cardiac apex. Serial echocardiographic and clinical examinations were performed. Follow-up varied from 1 to 30 months.

Results

A total of 12 transapical mitral ViV procedures were performed. Patients had a mean age of 61.6 ± 9.9 years and 92% were women. Mean logistic EuroSCORE was 20.1%. Successful valve implantation was possible in all cases. In one case, a right lateral thoracotomy was performed for the removal of an embolized prosthesis. There was no operative mortality. Thirty-day mortality was 8.3%. Ejection fraction was preserved after the implant (66.7%; 64.8%; P  = 0.3). The mitral gradient showed a significant reduction (11 mmHg; 6 mmHg; P  < 0.001). Residual mitral regurgitation was not present. There was no left ventricular outflow tract obstruction.

Conclusions

The mitral ViV implant in a failed bioprosthesis is an effective procedure. This possibility might alter prosthesis selection in the future initial surgical prosthesis selection, favouring bioprostheses. Further large trials should explore its safety.

Postoperative Right Ventricular Failure in Cardiac Surgery

Two cases of patients that developed right ventricular failure (RVF) after cardiac valve surgery are presented with a narrative revision of the literature. RVF involves a great challenge due to the severity of this condition; it has a low incidence among non-congenital cardiac surgery patients, is more likely associated with cardiovascular and pulmonary complications related to cardiopulmonary bypass (CPB), and is a cause of acute graft failure and of a higher early mortality in cardiac transplant. The morphologic and hemodynamic characteristics of the right ventricle and some specific factors that breed pulmonary hypertension after cardiac surgery are in favor of the onset of RVF. Due to the possibility of complications after cardiac valve repair or replacement, measures as appropriate hemodynamic monitoring, to manage oxygenation, ventilation, sedation, acid base equilibrium and perfusion goals are a requirement, as well as a normal circulating volume, and the prevention of a disproportionate rise in the afterload, to preserve the free wall of the right ventricle (RV) and the septum's contribution to the right ventricular global function and geometry. If there is no response to these basic measures, the use of advanced therapy with inotropics, intravenous or inhaled pulmonary vasodilation agents is recommended; the use of mechanical ventricular assistance stands as a last resource.

Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review

Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm(2). Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9-54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier-Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair.

Prosthesis-Patient Mismatch after Mitral Valve Replacement: Comparison of Different Methods of Effective Orifice Area Calculation

PURPOSE

The incidence of prosthesis-patient mismatch (PPM) after mitral valve replacement (MVR) has been reported to vary. The purpose of the current study was to investigate incidence of PPM according to the different methods of calculating effective orifice area (EOA), including the continuity equation (CE), pressure half time (PHT) method and use of reference EOA, and to compare these with various echocardiographic variables.

MATERIALS AND METHODS

We retrospectively reviewed 166 individuals who received isolated MVR due to rheumatic mitral stenosis and had postoperative echocardiography performed between 12 and 60 months after MVR. EOA was determined by CE (EOA(CE)) and PHT using Doppler echocardiography. Reference EOA was determined from the literature or values offered by the manufacturer. Indexed EOA was used to define PPM as present if ≤1.2 cm²/m².

RESULTS

Prevalence of PPM was different depending on the methods used to calculate EOA, ranging from 7% in PHT method to 49% in referred EOA method to 62% in CE methods. The intraclass correlation coefficient was low between the methods. PPM was associated with raised trans-prosthetic pressure, only when calculated by CE (p=0.021). Indexed EOA(CE) was the only predictor of postoperative systolic pulmonary artery (PA) pressure, even after adjusting for age, preoperative systolic PA pressure and postoperative left atrial volume index (p<0.001).

CONCLUSION

Prevalence of mitral PPM varied according to the methods used to calculate EOA in patients with mitral stenosis after MVR. Among the various methods used to define PPM, EOA(CE) was the only predictor of postoperative hemodynamic parameters.

Immediate and mid-term result of restrictive mitral annuloplasty using a small semi-rigid ring

OBJECTIVE

Though annuloplasty using a properly sized ring has been advocated in degenerative mitral regurgitation, restrictive annuloplasty using a down-sized ring is widely used in ischemic mitral regurgitation. We investigated the outcome of restrictive annuloplasty using a small (24- or 26-mm) ring in mitral regurgitation irrespective of the etiology.

METHODS

Nineteen patients underwent a restrictive annuloplasty using a 24-mm (n = 8) or 26-mm (n = 11) semi-rigid ring. The etiology included degenerative in 13 patients, ischemic in 3, endocarditis in 2, and congenital in 1. Body surface area of the patients implanted with the 24-mm ring was 1.40 ± 0.16 and 1.60 ± 0.18 m(2) for the 26-mm ring. Fifteen patients had 3+ or 4+ mitral regurgitation preoperatively.

RESULTS

Two patients were converted to valve replacement for residual mitral regurgitation during the operation. One operative mortality associated with infection was observed. Echocardiogram at 29.4 ± 14.2 months postoperatively demonstrated mitral valve area of 2.0 ± 0.6 cm(2) for 24-mm ring and 2.2 ± 0.5 cm(2) for 26-mm ring with indexed mitral valve area of 1.4 ± 0.4 cm(2)/m(2) for both groups, and no mitral regurgitation more than 2+. Transmitral mean pressure gradient on rest was 4.7 ± 2.1 mmHg at last follow up. New York Heart Association class improved from 2.2 ± 0.7 to 1.2 ± 0.2 after the operation. No late death or reoperation was observed during the follow-up of 31.0 ± 15.0 months.

CONCLUSIONS

Restrictive mitral annuloplasty using a small ring provided acceptable early and midterm results in patients with body surface area around 1.5 cm(2) without Barlow pathology. Restrictive annuloplasty may be another technical aspect to avoid valve replacement.

Predictors of Mortality in Patients Undergoing Mitral Valve Replacement

Objective:

Although mitral valve replacement is frequently performed in patients of all age groups, there are few studies available which determine the causes of operative mortality in mitral valve replacement especially in our region. Therefore, the objective of this study was to identify factors that are significantly associated with operative mortality in mitral valve replacement.

Methods:

From August 2012 to March 2013, 80 consecutive patients undergoing mitral valve replacement in a single tertiary hospital were included. Patients with a history of previous coronary artery bypass graft surgery or congenital heart problems were excluded from the sample. The included patients were observed for a period of 30 days. Pre and post-operative variables were used to identify significant predictors of mortality.

Results:

The overall hospital mortality (30 days) was 15%. High post-perative creatinine (P =0.05), high ASO titre (P=0.03), young age (P=0.011), low cardiac output (P=0.0001), small mitral valve size (P=0.002) and new onset of atrial fibrillation (P=0.007) were the significant independent predictors of operative morality.

Conclusion:

Mitral valve replacement can be performed in third world countries with limited resources with low mortality. However, optimal selection of mitral valve size can help to improve operative mortality.

Mitral valve area during exercise after restrictive mitral valve annuloplasty: importance of diastolic anterior leaflet tethering

BACKGROUND

Restrictive mitral valve annuloplasty (RMA) for secondary mitral regurgitation might cause functional mitral stenosis, yet its clinical impact and underlying pathophysiological mechanisms remain debated.

OBJECTIVES

The purpose of our study was to assess the hemodynamic and clinical impact of effective orifice area (EOA) after RMA and its relationship with diastolic anterior leaflet (AL) tethering at rest and during exercise.

METHODS

Consecutive RMA patients (n = 39) underwent a symptom-limited supine bicycle exercise test with Doppler echocardiography and respiratory gas analysis. EOA, transmitral flow rate, mean transmitral gradient, and systolic pulmonary arterial pressure were assessed at different stages of exercise. AL opening angles were measured at rest and peak exercise. Mortality and heart failure readmission data were collected for at least 20 months after surgery.

RESULTS

EOA and AL opening angle were 1.5 ± 0.4 cm(2) and 68 ± 10°, respectively, at rest (r = 0.4; p = 0.014). EOA increased significantly to 2.0 ± 0.5 cm(2) at peak exercise (p < 0.001), showing an improved correlation with AL opening angle (r = 0.6; p < 0.001). Indexed EOA (EOAi) at peak exercise was an independent predictor of exercise capacity (maximal oxygen uptake, p = 0.004) and was independently associated with freedom from all-cause mortality or hospital admission for heart failure (p = 0.034). Patients with exercise EOAi <0.9 cm(2)/m(2) (n = 14) compared with ≥0.9 cm(2)/m(2) (n = 25) had a significantly worse outcome (p = 0.048). In multivariate analysis, AL opening angle at peak exercise (p = 0.037) was the strongest predictor of exercise EOAi.

CONCLUSIONS

In RMA patients, EOA increases during exercise despite fixed annular size. Diastolic AL tethering plays a key role in this dynamic process, with increasing AL opening during exercise being associated with higher exercise EOA. EOAi at peak exercise is a strong and independent predictor of exercise capacity and is associated with clinical outcome. Our findings stress the importance of maximizing AL opening by targeting the subvalvular apparatus in future repair algorithms for secondary mitral regurgitation.

Echocardiographic Assessment of Heart Valve Prostheses

Patients submitted to valve replacement with mechanical or biological prosthesis, may present symptoms related either to valvular malfunction or ventricular dysfunction from other causes. Because a clinical examination is not sufficient to evaluate a prosthetic valve, several diagnostic methods have been proposed to assess the functional status of a prosthetic valve. This review provides an overview of echocardiographic and Doppler techniques useful in evaluation of prosthetic heart valves. Compared to native valves, echocardiographic evaluation of prosthetic valves is certainly more complex, both for the examination and the interpretation. Echocardiography also allows discriminating between intra- and/or peri-prosthetic regurgitation, present in the majority of mechanical valves. Transthoracic echocardiography (TTE) requires different angles of the probe with unconventional views. Transesophageal echocardiography (TEE) is the method of choice in presence of technical difficulties. Three-dimensional (3D)-TEE seems to be superior to 2D-TEE, especially in the assessment of paravalvular leak regurgitation (PVL) that it provides improved localization and analysis of the PVL size and shape.

Echocardiographic assessment of prosthetic heart valves

Valvular heart disease is a global health problem. It is estimated that more than 280,000 prosthetic heart valves are implanted worldwide each year. As the world's population is aging, the incidence of prosthetic heart valve implantation and the prevalence of prosthetic heart valves continue to increase. Assessing heart valve prosthesis function remains challenging, as prosthesis malfunction is unpredictable but not uncommon. Transthoracic two-dimensional and Doppler echocardiography is the preferred method for assessing prosthetic valve function. Clinically useful Doppler-derived measures for assessing prosthetic valve hemodynamic profiles have been reported for aortic, mitral, and tricuspid valve prostheses, but echocardiographic data regarding pulmonary valve prostheses remain limited. Complete prosthetic valve evaluation by transthoracic echocardiography (TTE) is sometimes challenging due to acoustic shadowing and artifacts. In these cases, further imaging with transesophageal echocardiography, fluoroscopy and/or gated CT may be warranted, particularly if prosthetic valve dysfunction is suspected. Being able to differentiate pathologic versus functional obstruction of an individual prosthesis is extremely important, as this distinction affects management decisions. Transprosthetic and periprosthetic regurgitation may be difficult to visualize on TTE, so careful review of Doppler-derived data combined with a high index of suspicion is warranted, particularly in symptomatic patients. A baseline TTE soon after valve implantation is indicated in order to "fingerprint" the prosthesis hemodynamic profile. It remains unclear how frequently serial imaging should be performed in order to assess prosthetic valve function, as this issue has not been systematically studied.