Simulating complex patient populations with hierarchical learning effects to support methods development for post-market surveillance

BACKGROUND

Validating new algorithms, such as methods to disentangle intrinsic treatment risk from risk associated with experiential learning of novel treatments, often requires knowing the ground truth for data characteristics under investigation. Since the ground truth is inaccessible in real world data, simulation studies using synthetic datasets that mimic complex clinical environments are essential. We describe and evaluate a generalizable framework for injecting hierarchical learning effects within a robust data generation process that incorporates the magnitude of intrinsic risk and accounts for known critical elements in clinical data relationships.

METHODS

We present a multi-step data generating process with customizable options and flexible modules to support a variety of simulation requirements. Synthetic patients with nonlinear and correlated features are assigned to provider and institution case series. The probability of treatment and outcome assignment are associated with patient features based on user definitions. Risk due to experiential learning by providers and/or institutions when novel treatments are introduced is injected at various speeds and magnitudes. To further reflect real-world complexity, users can request missing values and omitted variables. We illustrate an implementation of our method in a case study using MIMIC-III data for reference patient feature distributions.

RESULTS

Realized data characteristics in the simulated data reflected specified values. Apparent deviations in treatment effects and feature distributions, though not statistically significant, were most common in small datasets (n < 3000) and attributable to random noise and variability in estimating realized values in small samples. When learning effects were specified, synthetic datasets exhibited changes in the probability of an adverse outcomes as cases accrued for the treatment group impacted by learning and stable probabilities as cases accrued for the treatment group not affected by learning.

CONCLUSIONS

Our framework extends clinical data simulation techniques beyond generation of patient features to incorporate hierarchical learning effects. This enables the complex simulation studies required to develop and rigorously test algorithms developed to disentangle treatment safety signals from the effects of experiential learning. By supporting such efforts, this work can help identify training opportunities, avoid unwarranted restriction of access to medical advances, and hasten treatment improvements.

TrueVue transillumination volume rendering for three-dimensional transoesophageal echocardiography in interventional imaging

AIMS

The aim of the present article is to address the advantages of real-time TrueVue transillumination rendering for three-dimensional transoesophageal echocardiography in the context of echocardiographic procedural guidance for structural interventions for several procedural concerns.

METHODS

Procedures in which transillumination imaging was used during at least one step of the whole intervention were retrospectively collected; the loops were reviewed by an experienced imaging specialist and the most important concerns imaged in the loops were listed. The apparent added value of transillumination for each of these concerns was scored independently by two imager specialists, and their agreement was derived.

RESULTS

Between January and June 2019, 50 procedures were performed in our centre. Transillumination imaging was used in 64% of these cases. Considering all the loops the added value of transillumination compared with the conventional rendering was scored greater than 3 in a Likert scale in 87% of analysed loops by both the operators with a good agreement (κ  = 0.47, P  = 0.001). A different level of perceived advantage and agreement was observed between three image features that improved: substantial agreement (κ  = 0.652, P  = 0.001) for enhancing the contrast between structures and cavities (n  = 24 loops); good agreement for the contrast between different structures (κ  = 0.588, P  = 0.002) (n  = 37 loops); moderate agreement for the perception of interaction between the device and structures (κ  = 0.3, P  = 0.027) (n  = 7 loops).

CONCLUSION

The use of new volume-rendering techniques in interventional imaging may be useful especially for solving the concerns regarding the cavity-structure contrast.

Predictors of scaffold failure and impact of optimized scaffold implantation technique on outcome: Results from the German-Austrian ABSORB RegIstRy

AIMS

We aimed to investigate predictors of scaffold failure and the potential impact of an optimized scaffold implantation technique by means of a learning curve on long-term clinical outcome after bioresorbable scaffold (BRS) implantation and to evaluate predictors of scaffold failure.

METHODS AND RESULTS

A total of 3326 patients were included in this prospective, observational, multi-center study (ClinicalTrials.gov NCT02066623) of consecutive patients undergoing BRS implantation between November 2013 and January 2016. The 3144 patients completed follow-up after 24 months, 3265 patients were eligible for time-to-event-analysis. Clinical endpoints were major adverse cardiac events-a composite endpoint of death, target vessel revascularization and myocardial infarction, and scaffold thrombosis (ScT). Patients were grouped according to treatment before or since 2015. During follow-up MACE rate improved from 2.52% after 30 days, 5.45% after 6 months and 12.67% after 24 months to 1.52%, 3.44%, and 10.52%, respectively. A total of 75 ScT occurred. In multiple regression analysis, treatment of bifurcations, long lesions, and procedures performed earlier than 2014 were identified as predictors for the occurrence of ScT.

CONCLUSION

Treatment of bifurcation lesions is the strongest predictor of ScT following BRS implantation. A significantly lower incidence of ScT and 24-month target lesion revascularization in patients recruited after 2014 into our observational registry suggests the influence of a learning curve.

"Learning curve and procedural volume in mitral valve disease"

The impact of procedural volume on outcome results is a widespread topic in surgery, The importance of referral centers and high-volume hospitals have reached the forefront, particularly in mitral valve surgery, impacting the recommendations of the latest European and American guidelines. In this issue, Wayne et al. presented an interesting analysis of the relationship between surgeon and hospital procedural volume, mitral valve repair rates, and 30-day mortality for degenerative mitral regurgitation (MR) in Australia. Based on the database of the Australian and New Zealand Society of Cardiac and Thoracic Surgeons, they have shown how the surgeon and hospital caseload are significantly associated with repair rates of degenerative MR. This study reaches the same results presented by Chikwe et al. and others and corroborates what guidelines reported about the need for referral centers for mitral valve disease. These results are the reasons why many surgeons, as Adams et al., published papers to highlight the importance of a minimum mitral valve surgery volume threshold to achieve optimum results and discourage at the same time low-volume centers. The concept of minimum thresholds in mitral surgery suggested by Wayne et al. and previously by Vassileva et al. is fundamental to guarantee periprocedural safety, accuracy, and a high rate of reparation. Moreover, not only hospital volume but also surgeon yearly number of mitral valve interventions are crucial in valve repair rate and the threshold of 20 mitral procedures per year, proposed by Wayne et al., seems absolutely consistent with the literature.

Transseptal Puncture Learning Curve for Transcatheter Edge-to-Edge Mitral Valve Repair

OBJECTIVE

This study examined the learning curve for transseptal puncture (TSP) during transcatheter edge-to-edge mitral valve repair (TEER) performed by a dedicated mitral valve structural heart team. Effective TSP is mandatory for TEER but can be time-consuming and associated with complications including pericardial effusion and cardiac tamponade.

METHODS

TSP was performed on 107 consecutive patients (76 ± 1 years, 52% male) undergoing TEER between 2014 and 2019. TSP was performed by each structural heart team member (1 cardiologist, 2 cardiac surgeons) on a rotating case-by-case basis. No team member had prior independent TSP experience. Data collected included total procedure time, TSP time (time elapsed between procedure start and septal crossing), and number of TSP attempts before successful puncture. Cumulative sum (CUSUM) of deviations from the mean across sequential cases were used to examine learning curves.

RESULTS

Median total procedure time was 107 min, and the median TSP time was 14 min. Greater case number was significantly associated with both lower TSP time (r _s = -0.22, P = 0.022) and lower total procedure time (r _s = -0.29, P = 0.003). The majority of patients required only 1 TSP attempt (79%). There was a significant quadratic relationship between case number and the CUSUM for TSP time, with the learning curve peaking at 49 cases.

CONCLUSIONS

TSP for TEER has a substantial learning curve, requiring >50 cases to achieve acceptable efficiency. Even once proficiency is demonstrated, TSP remains a time-consuming component of TEER. Improvements in transseptal access technology may significantly decrease the time needed to master TSP and may improve the safety and precision of the procedure.

Transcatheter edge-to-edge mitral valve repair with the PASCAL system: early results from a real-world series

AIMS

This study sought to characterise the real-world performance and clinical outcomes of the PASCAL system, a leaflet approximation device for transcatheter mitral valve repair.

METHODS AND RESULTS

Fifty patients in NYHA Class II-IV despite optimal medical therapy (median age 78.0 years [IQR 74.5-81.0], 52% female, log EuroSCORE 21.6 [IQR 13.2-30.2]) were treated for severe mitral regurgitation (MR) and followed up for one month. Primary and secondary MR was present in 24% and 68% of patients, respectively, with a mixed aetiology observed in 8%. A 1-device strategy was employed in 26/50 patients (52%), a 2-device strategy in 23/50 (46%) patients, and a 3-device strategy in 1/50 (2%) patients. Technical and procedural success was achieved in 100% and 98% of patients, respectively. MR grade ≤1 was observed in 39/50 (78%) patients at discharge, and in 36/46 (78%) patients at one month, with transvalvular gradients remaining ≤5 mmHg in all patients. One device embolisation and one single leaflet device attachment were observed during follow-up. After one month, 73% of patients reported an improvement in NYHA class, and six-minute walk test distance increased by 73±12 m in patients without relevant tricuspid regurgitation.

CONCLUSIONS

In a real-world population, the PASCAL device effectively reduces MR and leads to functional improvements on short-term follow-up.

Adjunctive use of fluoroscopy during MitraClip implantation reduces procedural complexity: The parallax technique

BACKGROUND

During MitraClip implantation sub-valvular correction of trajectory and/or alignment may increase adverse clip or leaflet events. With systematic adjunctive use of fluoroscopy ("Parallax technique"), we aimed to assess parameters that minimize the need for corrective measures and help increase procedural efficiency.

METHODS

We retrospectively analyzed 30 patients without (Fl-) and 39 patients utilizing adjunctive fluoroscopy (Fl+) during MitraClip implantation. After establishing trajectory and supra-valvular alignment, the Parallax technique was utilized. Trajectory and alignment are maintained during advancement.

RESULTS

All patients had 3 or 4+ MR. There were no differences in baseline demographics. The average number of clips (Fl- vs Fl+) was 1.72 ± 0.8 vs 1.59 ± 0.5, p = .57. For the first clip, the need for sub-valvular alignment (80% vs. 36%, p = .0001), eversion with retraction back to left atrium (23% vs. 10%, p = .001) and the number of grasps (2.3 ± 1.2 vs 1.4 ± 0.9) was reduced. The time from transseptal puncture to first clip deployment (71 ± 21 vs 44 ± 16 min, p = .01) was reduced. Procedural success was achieved in all but one patient in the Fl- group (p = ns). There were no differences noted for in-hospital or 30-day outcomes.

CONCLUSIONS

Systematic use of a simple and easy to implement "Parallax technique" was associated with reduced need for sub-valvular manipulation and was associated with improved procedural times. Further larger scale studies are needed to assess the applicability of the technique.

Cost-effectiveness analysis of percutaneous mitral valve repair with the MitraClip delivery system for patients with mitral regurgitation in Japan

Aims: The objective of the study is to evaluate the cost-effectiveness of percutaneous mitral valve repair (TMVr) with the MitraClip NT system (MitraClip procedure) for patients with symptomatic severe mitral regurgitation (MR) at high surgical risk in line with the methodological guideline for cost-effectiveness evaluation by the Ministry of Health, Labour and Welfare.Material and Methods: The cost-effectiveness of MitraClip procedure was evaluated using a Markov model. Patients are classified into four New York Heart Association classes in each cycle. The model considered MitraClip complication ("major vascular complication", "major bleeding complication", "non-cerebral thromboembolism"), adverse events, re-implantation with MitraClip device, mitral valve surgery, and congestive heart failure hospitalization. For the evidence on additional benefits, a study compared with propensity score-matched medical therapy group was used in the analysis. The analysis was conducted from the perspective of a public healthcare payer with a discount rate of 2% for both cost and effectiveness.Results: In the base-case analysis, total cost and quality-adjusted life year (QALY) gained (Life year (LY) gained) were 7,541,151 JPY and 3.23 QALYs (3.85 LYs) for MitraClip group, and 4,699,692 JPY and 1.79 QALYs (2.43 LYs) for medical therapy group, respectively. The incremental cost-effectiveness ratio (ICER) of MitraClip procedure versus medical therapy was 1.97 million JPY/QALY (US$18,570/QALY, US$1 = 106 JPY), which was evaluated to be cost-effective. The probability of ICER of MitraClip procedure versus medical therapy being 5 million JPY/QALY was 96.7%.Limitations: There are two limitations. Firstly, the parameters for the comparators were based on some assumptions. However, it was a conservative setting against MitraClip group. Secondary, the mortality rate and adverse events of MitraClip group in a lifetime were estimated from data during a year after the procedure.Conclusions: MitraClip procedure improved life-years and quality of life in patients at high surgical risk and it was also a cost-effective treatment option.

Relation of Hospital Volume With In-Hospital and 90-Day Outcomes After Transcatheter Mitral Valve Repair Using MitraClip

MitraClip therapy has shown increasing use since it was commercially adopted among US hospitals in October 2013. However, the relation of institutional MitraClip volume with outcomes is unclear. This study sought to examine the association between hospital volume and outcomes after transcatheter mitral valve repair using the MitraClip device. Using the Nationwide Readmissions Database, we identified all patients who underwent a MitraClip procedure and categorized hospitals into tertiles based on their annual procedure volume: low (≤3 procedures/year), medium (4 to 13/year), and high (≥14/year) volume centers. Multivariable logistic and Cox regression analyses were performed to examine the impact of institutional MitraClip volume on in-hospital and 90-day outcomes, respectively. From 2014 to 2015, a total of 3,420 procedures were performed at 266 hospitals with a median annual procedural volume of 5 per hospital. Low (n = 81), medium (n = 86), and high (n = 99) volume hospitals performed 147 (4.3%), 403 (11.8%), and 2,870 (83.9%) MitraClip procedures, respectively. The low versus high hospital volume was independently associated with increased in-hospital mortality (7.8% vs 3.0%; adjusted odds ratio [aOR] 2.64; p = 0.04), acute myocardial infarction (10.2% vs 2.2%; aOR 2.93; p = 0.02), and acute respiratory failure (19.3% vs 7.7%; aOR 2.24; p = 0.02) during index admission as well as 90-day all-cause readmissions (37.8% vs 26.6%; adjusted hazard ratio 1.54; p = 0.03), and 90-day infective endocarditis (2.4% vs 0.3%; adjusted hazard ratio 10.06; p = 0.003). In conclusion, low hospital MitraClip volume is an independent determinant of worse outcomes including in-hospital mortality and 90-day readmissions.

Short-term and 1-year outcomes after MitraClip therapy in functional versus degenerative mitral regurgitation patients: a systematic review and meta-analysis

Background

Differences in short-term and 1-year outcomes of percutaneous edge-to-edge mitral repair between patients with functional and degenerative mitral regurgitation (MR) remain unclear. We performed a systematic review and meta-analysis to investigate the safety and efficacy of MitraClip (MC) in patients with different MR etiologies.

Methods

This study systematically searched three common databases for studies on MC therapy until November 2017. The studies meeting the standard inclusion criteria were included. The data at baseline, short-term and 1-year clinical and echocardiographic outcomes were obtained and analyzed. All data were checked by another reviewer.

Results

Thirteen studies totalling 2,351 patients investigating the short-term and 1-year outcomes of MC in patients with functional MR (FMR) versus degenerative MR (DMR) were included for further analysis. FMR patients presented a higher risk profile at baseline. There was no difference in short-term outcomes between DMR and FMR for post-procedural MR grade 0-2 (76.8% vs. 77.1%; P=0.428), mean trans-mitral gradient (3.92 vs. 3.50 mmHg; P=0.098), 30-day mortality rate (0.05% vs. 0.03%; P=0.118) and 30-day NYHA I-II (85.3% vs. 78.7%; P=0.211). FMR patients had a higher rate of acute procedural success compared to the DMR patient group (91.2% vs. 95.2%; P=0.016). A greater portion of DMR patients implanted two or more MCs than the FMR patients (41.4% vs. 35.7%; P=0.043). For the 1-year outcomes, no difference was found in the mortality rate (13.0% vs. 15.2%; P=0.268) and proportion of patients with post-procedural MR grades 0-2 (75.0% vs. 80.7%; P=0.106).

Conclusions

Despite a higher risk profile in FMR patients, the short-term and 1-year outcomes were not significantly different. We conclude that MC therapy is similar between FMR and DMR patients until 1-year follow-up. Large randomized trials are warranted to fully and further assess the clinical impact of the procedure in these two MR etiologies over a longer period of time.

Impact of Preprocedural Anemia on Outcomes ofPatients With Mitral Regurgitation Who UnderwentMitraClip Implantation

MitraClip is a novel therapeutic option for mitral regurgitation (MR). Anemia is associated with unfavorable outcomes of patients with cardiovascular diseases. In this study, we aimed to clarify the effect of preprocedural anemia on outcomes of patients who underwent MitraClip implantation. Anemia was defined as a serum hemoglobin level of <13 g/dl in men and <12 g/dl in women according to the World Health Organization criteria. Among the 392 patients receiving MitraClip implantation, anemia was prevalent in 56% (n = 220). Men tended to be more common in patients with anemia (71% vs 62%, p = 0.069). Patients with anemia were older than those without anemia (76 ± 8 vs 74 ± 10years, p = 0.008). Baseline New York Heart Association class IV (35 vs 22%, p = 0.006) and chronic kidney disease (79 vs 67%, p = 0.011) were more common in patients with anemia. Severity of MR was similar at baseline in the two groups, and it equally improved after MitraClip implantation. Despite similar improvement in MR, N-terminal pro b-type natriuretic peptide did not decrease in patients with anemia, and Kaplan-Meier curves showed that patients with anemia had lower survival (log-rank p = 0.013). After adjustment for covariates, preprocedural anemia was still associated with higher mortality after MitraClip implantation (p = 0.027, hazard ratio 1.802). The negative prognostic impact of preprocedural anemia was prominent in patients with higher baseline N-terminal of pro-Brain Natriuretic Peptide. These results suggest that preprocedural anemia was common and negatively affected patient survival. Establishing optimal management of anemia before MitraClip implantation is necessary, particularly for patients with severe heart failure.

Comparison of Transcatheter Mitral Valve Repair Versus Surgical Mitral Valve Repair in Patients With Advanced Kidney Disease (from the National Inpatient Sample)

Transcatheter mitral valve repair (TMVR) is an emerging treatment modality that has been reserved for high-risk patients with multiple co-morbidities. We hypothesize that TMVR is a safe and effective procedure for patients with moderate to severe mitral regurgitation who are not surgical candidates. The National Inpatient Sample (2012 to 2014) using the International Classification of Diseases, 9th Revision, Clinical Modification procedure codes 35.97 for TMVR and 35.12 for surgical mitral valve repair (SMVR) were used. Patients with chronic kidney disease stage IV, Stage V, and end-stage renal disease (ESRD) were considered as patients with advanced kidney disease. A total of 2,123 patients were treated with SMVR and 74 patients were treated with TMVR. There were notably fewer patients treated with TMVR compared with patients treated with SMVR. The mean age was higher with the TMVR group (72.4 vs 61.7 years, p = <0.001). After performing multivariate regression analysis, the primary outcome of in-hospital mortality (13.8% vs 1.3%, adjusted p = 0.003) and all secondary outcomes, excluding dialysis requirement, cardiogenic shock, and cardiac arrest, were significantly lower with the TMVR approach. The average length of stay was lower with TMVR compared with SMVR (22.8 vs 12.6 days, adjusted p = <0.001), with reduced in-hospital costs ($98,165 vs $52,646, adjusted p = <0.001). This large, national study suggests TMVR is associated with significantly lower in-patient morbidity and mortality, with significant cost savings in patients with advanced kidney disease compared with SMVR. Hence, TMVR could be a safe and effective alternative for patients with advanced kidney disease who are not surgical candidates.

Acute and Long-Term Hemodynamic Effects of MitraClip Implantation on a Preexisting Secondary Right Heart Failure

Positive results of MitraClip in terms of improvement in clinical and left ventricular parameters have been described in detail. However, long-term effects on secondary pulmonary hypertension were not investigated in a larger patient cohort to date. 70 patients with severe mitral regurgitation, additional pulmonary hypertension, and right heart failure as a result of left heart disease were treated in the heart centers Hamburg and Göttingen. Immediately after successful MitraClip implantation, a reduction of the RVOT diameter from 3.52 cm to 3.44 cm was observed reaching a statistically significant value of 3.39 cm after 12 months. In contrast, there was a significant reduction in the velocity of the tricuspid regurgitation (TR) from 4.17 m/s to 3.11 m/s, the gradient of the TR from 48.5 mmHg to 39.3 mmHg, and the systolic pulmonary artery pressure (PAPsyst) from 58.6 mmHg to 50.0 mmHg. This decline continued in the following months (V_max TR 3.09 m/s, peak TR 38.6 mmHg, and PAPsyst 47.4 mmHg). The tricuspid annular plane systolic excursion (TAPSE) increased from 16.5 mm to 18.9 mm after 12 months. MitraClip implantation improves pulmonary artery pressure, tricuspid regurgitation, and TAPSE after 12 months. At the same time, there is a decrease in the RVOT diameter without significant changes in other right ventricular and right atrial dimensions.

Left ventricular ejection fraction of < 20%: Too bad for MitraClip© ?

OBJECTIVES

This study sought to investigate whether the percutaneous mitral regurgitation (MR) reduction with the MitraClip® system in end-stage heart failure patients with a left ventricular ejection fraction (LVEF) of <20% also effects beneficial outcome or whether the underlying myogenic problem is leading and therefore of prognostic relevance.

BACKROUND

The interventional treatment of functional mitral regurgitation (FMR) with the MitraClip^® system could improve the clinical and hemodynamic outcome in patients with severely impaired left ventricular function.

MATERIALS AND METHODS

Between 2011 and 2016, a total of 147 patients with FMR were treated with MitraClip^® at our institution. The cohort was divided into two groups: LVEF ≥ 20% (N = 126) and <20% (N = 21). Follow-up assessments included exercise capacity, 6-min walk test, probrain natriuretic peptide-measurement (ProBNP), echocardiography and right heart catheterization. Only three patients with an LVEF ≥ 20% and one patient with an LVEF < 20% were lost for follow-up.

RESULTS

In the vast majority of patients, a reduction from severe to mild MR was demonstrated with no difference between both groups (P = 0.422). At follow-up, both subgroups experienced similar improvements in exercise capacity and hemodynamics. Patients with an LVEF < 20% were on average 5.8 years younger, while mortality rates were comparable in both groups (P = 0.760).

CONCLUSION

By careful selection, even patients in the end stage of advanced LV dysfunction as the result of the underlying myogenic problem and the additional harmful effects of the high volume loading due to the FMR can exhibit significant clinical and hemodynamic improvement after MitraClip^© therapy.

AVJ-514 Trial - Baseline Characteristics and 30-Day Outcomes Following MitraClip® Treatment in a Japanese Cohort

BACKGROUND

The MitraClip^®system is a transcatheter-based therapeutic option for patients with chronic mitral regurgitation (MR) who are at high risk for surgery. A prospective, multicenter, single-arm study was initiated to confirm the transferability of this system to Japan.Methods and Results:Patients with symptomatic chronic moderate-to-severe (3+) or severe (4+) functional or degenerative MR with a Society of Thoracic Surgery (STS) score ≥8%, or the presence of 1 predefined risk factor were enrolled. Patients with left ventricular (LV) ejection fraction (EF) <30% were excluded. MR severity and LV function were assessed by an independent echocardiography core lab. Primary outcome included major adverse events (MAE) at 30 days and acute procedural success (APS). A total of 30 patients (age: 80±7 years; STS score: 10.3%±6.6%) were treated with the MitraClip^®. At baseline, all patients had MR 3+/4+ with 53%/47% patients with degenerative/functional etiology with mean LVEF of 50.2±12.8%, and 37% of patients were NYHA class III/IV. APS was achieved in 86.7% with no occurrence of MAE. At 30 days, 86.7% of patients had MR ≤2+ and 96.7% were NYHA class I/II.

CONCLUSIONS

The MitraClip^®procedure resulted in clinically meaningful improvements in MR severity, function and quality of life measures, and low MAE rates. These early results suggest the transferability of this therapy to appropriately selected Japanese patients. (Trial Registration: clinicaltrials.gov Identifier NCT02520310.).

Immediate and 12-Month Outcomes of Ischemic Versus Nonischemic Functional Mitral Regurgitation in Patients Treated With MitraClip (from the 2011 to 2012 Pilot Sentinel Registry of Percutaneous Edge-To-Edge Mitral Valve Repair of the European Society of Cardiology)

In literature, there are limited data comparing ischemic mitral regurgitation (I-MR) versus nonischemic MR regarding outcomes after percutaneous "edge-to-edge" repair. We aimed to describe the early and 12-month results after MitraClip device implantation regarding the 2 etiologies. From January 2011 to December 2012, the Transcatheter Valve Treatment Sentinel Pilot Registry included 452 patients with MR who underwent MitraClip procedure in 25 centers across Europe. The prevalent etiology was I-MR (235 patients, 52.0%). I-MR group had a significantly higher proportion of men (74.9 vs 59.9%, p <0.001) and surgical risk (logistic EuroSCORE 24.8 ± 18.2 vs 18.8 ± 16.3, p <0.001). Acute procedural success was high (96%) and similar between groups (p = 0.48). Patients with I-MR required a higher, albeit not significant, number of clips to reduce MR (p = 0.08). Inhospital mortality was low (2.0%) without significant differences between etiologies. The estimated 1-year mortality and rehospitalization rates were 15.0% and 25.8%, respectively, without significant differences between groups. Paired echocardiographic data showed a persistent improvement of MR at 1 year in both etiologies. Despite a significant overall reverse atrial remodeling after clip, there were no significant changes in left ventricular volumes. In conclusion, this large independent cohort showed that percutaneous "edge-to-edge" therapy was associated with early- and long-term improvement of MR severity and functional condition both in patients with I-MR and nonischemic MR. There were no significant differences between the 2 etiologies regarding survival and freedom from rehospitalization due to heart failure at the 1-year follow-up.

MitraClip step by step; how to simplify the procedure

The MitraClip system is a device for percutaneous edge-to-edge reconstruction of the mitral valve in patients with severe mitral regurgitation who are deemed at high risk for surgery. Studies have underlined the therapeutic benefit of the MitraClip system for patients at extreme and high risk for mitral valve surgery, suffering from either degenerative or functional mitral regurgitation. The MitraClip procedure shows low peri-procedural complication rates, and a significant reduction in mitral regurgitation, as well as an improvement in functional capacity and most importantly quality of life. It hereby widens the spectrum of mitral valve repair for the Heart Team. The current review underscores the efficacy of the procedure and describes the technique to simplify the procedure.

Impact of residual mitral regurgitation after MitraClip implantation

BACKGROUND

MitraClip (MC) is an alternative treatment for mitral regurgitation (MR). Although residual MR is common after MC, little was known about the impact of residual MR after MC.

METHODS

We examined 255 consecutive patients who underwent MC. The primary endpoint was the composite endpoint including all-cause death, left ventricular (LV) assist device, and mitral valve surgery.

RESULTS

Procedure failure defined as unsuccessful MC implantation (n=6) and residual MR ≥3+ (n=19) was associated with worse outcomes including the primary endpoint and all-cause death than those with acute procedure success (APS) defined as residual MR 2+ (n=125) or 1+ (n=105). Among patient with APS, background characteristics including age, MR etiology, heart failure severity, and LV function were not different. Although MR grade and NT-pro BNP level at 6months after MC were higher in patients with residual MR 2+, there was no significant difference in the incidence of the primary endpoint and all-cause death. Subanalysis showed that the primary endpoint occurred more frequently in patients with MR 2+ in patients with LV ejection fraction ≤40%, chronic kidney disease, and baseline NYHA-class IV.

CONCLUSION

Procedure failure was associated with adverse outcomes after MC. Among patients with APS, residual MR 2+ was not significantly associated with overall worse outcomes than residual MR 1+. However, residual MR 2+ was associated with poorer prognosis in patients with impaired LV function, renal dysfunction, and severe heart failure, suggesting that the optimal endpoint of MC procedure should be individualized according to each patient's baseline characteristic.

Managing mitral regurgitation: focus on the MitraClip device

Based on the principle of surgical edge-to-edge mitral valve repair (MVR), the MitraClip percutaneous MVR technique has emerged as a minimally invasive option for MVR. This catheter-based system has been widely demonstrated to be safe, although inferior to surgical MVR. Studies examining patients with ≥3+ mitral regurgitation (MR) show that, for all patients treated, freedom from death, surgery, or MR ≥3+ is in the 75%–80% range 1 year following MitraClip implantation. Despite its inferiority to surgical therapy, in high-risk surgical patients, data suggest that the MitraClip system can be employed safely and that it can result in symptomatic improvement in the majority of patients, while not precluding future surgical options. MitraClip therapy also appears to reduce heart failure readmissions in the high-risk cohort, which may lead to an economic benefit. Ongoing study is needed to clarify the impact of percutaneous mitral valve clipping on long-term survival in high-risk populations, as well as its role in other patient populations, such as those with functional MR.

Impact of left ventricular systolic dysfunction on the outcomes of percutaneous edge-to-edge mitral valve repair using MitraClip

Left ventricular systolic dysfunction (LVD) is associated with poor outcomes after mitral regurgitation (MR) surgery. MitraClip (MC) is a novel treatment option for MR patients with a high surgical risk. However, outcomes of LVD patients underwent MC remain unclear. In total of 194 patients after MC implantation, 75 patients (39 %) had severe LVD (LV ejection fraction ≤30 %). Patients with severe LVD were primarily male and also younger. Logistic euroSCOREs were comparable between the two groups. Functional MR was more common in patients with severe LVD, while New York Heart Association (NYHA) class was similar between the two groups. N-terminal pro-B-type natriuretic peptide (NT-proBNP) was significantly higher in patients with LVD. In addition to similar improvements in MR severity, NYHA class, and NT-proBNP levels, the survival rates were not different between patients with and without severe LVD. Among patients with severe LVD, the long-term survival rates were significantly lower in patients aged ≥75 years, those with NT-proBNP >5000 pg/mL, and those with atrial fibrillation (AF). In conclusion, severe LVD was not associated with the mortality after MC implantation. MC might be feasible and effective even in the patients with severe MR and low LVEF. However, we need to carefully observe severe LVD patients who are elderly, have a high NT-proBNP level, and have AF, as these might be considered high-risk subjects.

Deep sedation versus general anesthesia in percutaneous edge-to-edge mitral valve reconstruction using the MitraClip system

BACKGROUND

Percutaneous edge-to-edge mitral valve reconstruction (PMVR) has emerged as a treatment option in patients with severe mitral regurgitation not considered suitable candidates for surgery. The majority of PMVR procedures are performed under general anesthesia (GA), although deep sedation (DS) appears to be an attractive alternative. We thus sought to assess the impact on intensive care unit (ICU) length of stay, efficacy, and safety of DS in comparison to GA in patients undergoing PMVR using the MitraClip(®) system.

METHODS

Sixty consecutive patients underwent PMVR procedures at two centers. The first 30 patients were treated by GA followed by 30 patients undergoing DS under different settings. The primary clinical endpoint was ICU length of stay. The primary efficacy endpoint included procedural success and procedural duration. The safety endpoint was defined as a composite of death, stroke, cardiogenic shock, moderate and severe bleeding as well as pneumonia.

RESULTS

The ICU length of stay was significantly shorter in the DS group in comparison to GA patients (p = 0.001). The hospital length of stay did not differ following DS in comparison to GA (p = 0.96). Procedural success was high in both groups (100 versus 96.7 %, p = 0.34) at similar procedural duration time (p = 0.60). No difference between GA and DS was observed with respect to the occurrence of the combined safety endpoint (p = 0.47).

CONCLUSIONS

In comparison to GA, DS reduces the ICU length of stay in PMVR without negative effects on safety and efficacy. Prospective randomized trials are needed to confirm these findings.

Acute and Midterm Outcome After MitraClip Therapy in Patients With Severe Mitral Regurgitation and Left Ventricular Dysfunction

The clinical outcome of patients with severe primary and secondary mitral regurgitation (MR) and heart failure or significantly reduced left ventricular ejection fraction (LVEF) who underwent percutaneous mitral valve repair (pMVR) is yet not well known. This study compares midterm outcome of patients with severe left ventricular dysfunction (EF ≤30%) versus patients with slightly or moderately reduced or normal LVEF (EF >30%) after pMVR. One hundred thirty-six consecutive patients were enrolled: 42 patients displayed severe left ventricular dysfunction, group 1 (logistic EuroSCORE I 27.7 ± 21.8%; secondary MR in 37 patients), and 94 patients displayed slightly or moderately reduced or normal LVEF, group 2 (logistic EuroSCORE I 17 ± 18.2%; secondary MR in 21 patients). The primary efficacy endpoint was death of any cause, repeat mitral valve intervention, and/or New York Heart Association class ≥III, which was reached in 31% of patients in group 1 versus 40% in group 2 (p = 0.719) at a median follow-up of 371 days. MR, graded by transthoracic echocardiography, was reduced in both groups (p <0.001) and New York Heart Association class improved in each group (p <0.001), with no differences between groups (p >0.05). In conclusion, at midterm follow-up, the pMVR provided significant clinical benefits with comparable results achieved both in patients with significantly reduced and in patients with moderately reduced to normal LVEF. Thus, pMVR represents a feasible and effective treatment in high-risk patients who otherwise have limited therapeutic options and no safe option to reduce MR.

Meta-analysis of the usefulness of Mitraclip in patients with functional mitral regurgitation

Midterm outcomes for patients presenting with heart failure and functional mitral regurgitation (MR) treated with Mitraclip remain unclear. Pubmed, Medline, and Google Scholar were systematically searched for studies enrolling patients with severe-moderate MR who underwent Mitraclip implantation. All events after at least 6 months were the primary safety end point (including death, rehospitalization for heart failure, and reinterventions), whereas change in the ejection fraction, left ventricular volumes, arterial pulmonary pressure, and left atrial diameters were considered as secondary end points. Meta-regression analysis was performed to evaluate the effect of baseline clinical and echocardiographic parameters on efficacy outcomes: 875 patients were included in 9 studies; 1.48 clips (1.3 to 1.7) for patients were implanted, and after a median follow-up of 9 months (6 to 12), 409 patients (78% [75% to 83%]) were in class New York Heart Association I/II and 57 (11% [8% to 14%]) still had moderate-to-severe MR. Overall adverse events occurred in 137 (26% [20% to 31%]) of the patients and 78 (15% [1% to 17%]) of them died; 6-minute walk test improved by 100 m (83 to 111), whereas a significant reduction in left ventricular volumes and systolic pulmonary pressure was reported. At meta-regression analysis, an increase in left ventricle systolic volumes positively affected reduction of volumes after Mitraclip, whereas atrial fibrillation reduced the positive effect of the valve implantation on ejection fraction on end-diastolic and -systolic volumes. In conclusion, Mitraclip represents an efficacious strategy for patients with heart failure and severe MR. It offers a significant improvement in functional class and in cardiac remodeling, in patients with severely dilated hearts as well, although its efficacy remains limited in the presence of atrial fibrillation.

Long-term survival after MitraClip(®) therapy in patients with severe mitral regurgitation and severe congestive heart failure: A comparison among survivals predicted by heart failure models

BACKGROUND

The aim of the study was to investigate mortality following transcatheter mitral valve repair with the MitraClip System (MC) (Abbott Vascular, Santa Clara, CA, USA) in patients with mitral regurgitation and moderate-to-severe symptomatic heart failure in comparison to mortality predicted by the Seattle Heart Failure Model (SHFM) and the heart failure calculator of the meta-analysis global group in chronic heart failure (MAGGIC).

METHODS AND RESULTS

This retrospective study included 194 consecutive patients, who received a MC implantation between 2009 and 2013 at our institution. The observed mortality was compared with that predicted by the SHFM and the MAGGIC after 1 year: 24% observed, 18% by SHFM (p=0.185) and 20.9% by MAGGIC (p=0.542). At 2 years: 32% observed vs. 33% by SHFM (p=0.919). The subgroup of patients with end-stage heart failure and N-terminal pro-B-type natriuretic peptide (NTproBNP) >10,000pg/ml (n=41) had significantly worse mortality after 1 year (49%) than predicted by SHFM (24%, p=0.034) and MAGGIC (24.8%, p=0.041).

CONCLUSION

In the overall patient cohort defined by 3+ to 4+ mitral valve regurgitation with New York Heart Association III and IV symptomatic heart failure, mortality following MC is consistent with that predicted by SHFM and MAGGIC for patients that are not at high risk. However, the subset of patients with severe heart failure defined by NTproBNP >10,000pg/ml had worse than predicted mortality and may not benefit from MC therapy, mainly due to a high 30-day mortality.

Comparative effectiveness of Mitraclip plus medical therapy versus medical therapy alone in high-risk surgical patients: a comprehensive review

In recent years, Mitraclip has become available as a treatment option for mitral regurgitation in high-risk surgical patients. Focusing on the incremental effectiveness of Mitraclip versus the current standard of care, this article provides a comparative review of the evidence on Mitraclip and standard medical therapy (MT) in high-risk mitral regurgitation patients. Evidence was retrieved from seven major databases. Results suggest that Mitraclip presents a high safety profile and a good middle-term effectiveness performance. Evidence on long-term effectiveness is limited both for Mitraclip and MT. Few studies allow a comparison with MT and comparative results on different endpoints are mixed. Therefore, the available evidence does not conclusively inform whether or under which circumstances Mitraclip should be preferred over MT in the treatment of high-risk patients. Head-to-head real-world studies would be needed, as they would provide great and timely insights to support policy decisions when medical devices are at stake.

The future of transcatheter mitral valve interventions: competitive or complementary role of repair vs. replacement?

Transcatheter mitral interventions has been developed to address an unmet clinical need and may be an alternative therapeutic option to surgery with the intent to provide symptomatic and prognostic benefit. Beyond MitraClip therapy, alternative repair technologies are being developed to expand the transcatheter intervention armamentarium. Recently, the feasibility of transcatheter mitral valve implantation in native non-calcified valves has been reported in very high-risk patients. Acknowledging the lack of scientific evidence to date, it is difficult to predict what the ultimate future role of transcatheter mitral valve interventions will be. The purpose of the present report is to review the current state-of-the-art of mitral valve intervention, and to identify the potential future scenarios, which might benefit most from the transcatheter repair and replacement devices under development.

Learning curves for cardiothoracic and vascular surgical procedures--a systematic review

OBJECTIVES

The aim of this systematic review is to evaluate the learning curve (LC) literature and identify the LC of cardiothoracic and vascular surgical procedures.

SUMMARY AND BACKGROUND

The LC describes an observation that a learner's performance improves over time during acquisition of new motor skills. Measuring the LC of surgical procedures has important implications for surgical innovation, education, and patient safety. Numerous studies have investigated LCs of isolated operations in cardiothoracic and vascular surgeries, but a lack of uniformity in the methods and variables used to measure LCs has led to a lack of systematic reviews.

METHODS

The MEDLINE®, EMBASE™, and PsycINFO® databases were systematically searched until July 2013. Articles describing LCs for cardiothoracic and vascular procedures were included. The type of procedure, statistical analysis, number of participants, procedure setting, level of participants, outcomes, and LCs were reviewed.

RESULTS

A total of 48 studies investigated LCs in cardiothoracic and vascular surgeries. Based on operating time, the LC for coronary artery bypass surgery ranged between 15 and 100 cases; for endoscopic vessel harvesting and other cardiac vessel surgery between 7 and 35 cases; for valvular surgery, which included repair and replacement, between 20 and 135 cases; for video-assisted thoracoscopic surgery, between 15 and 35 cases; for vascular neurosurgical procedures between 100 and 500 cases, based on complications; for endovascular vessel repairs between 5 and 40 cases; and for ablation procedures between 25 and 60 cases. However there was a distinct lack of standardization in the variables/outcome measures used, case selection, prior experience, and supervision of participating surgeons and a range of statistical analyses to compute LCs was noted.

CONCLUSION

LCs in cardiothoracic and vascular procedures are hugely variable depending on the procedure type, outcome measures, level of prior experience, and methods/statistics used. Uniformity in methods, variables, and statistical analysis is needed to derive meaningful comparisons of LCs. Acknowledgment and application of learning processes other than those reliant on volume-outcomes relationship will benefit LC research and training of surgeons.

Failure of acute procedural success predicts adverse outcome after percutaneous edge-to-edge mitral valve repair with MitraClip

AIMS

MitraClip implantation is evolving as a potential alternative treatment to conventional surgery in high-risk patients with significant mitral regurgitation (MR). However, outcome predictors are under-investigated. The aim of this study was to identify predictors of midterm mortality and heart failure rehospitalisation after percutaneous mitral valve repair with MitraClip.

METHODS AND RESULTS

A total of 150 consecutive patients were followed for a median of 463 days. Survival analyses were performed for baseline characteristics, risk scores and failure of acute procedural success (APS) defined as persisting MR grade 3+ or 4+. Univariate significant risk stratifiers were tested in multivariate analyses using a Cox proportional hazards model. Overall survival was 96% at 30 days, 79.5% at 12 months, and 62% at two years. Multivariate analysis identified APS failure (HR 2.13, p=0.02), NYHA Class IV at baseline (HR 2.11, p=0.01) and STS score ≥12 (HR 2.20, p<0.0001) as significant independent predictors of all-cause mortality, and APS failure (HR 2.31, p=0.01) and NYHA Class IV at baseline (HR 1.89, p=0.03) as significant independent predictors of heart failure rehospitalisation. Furthermore, a post-procedural significant decrease in hospitalisation rate could only be observed after successful interventions (0.89±1.07 per year before vs. 0.54±0.96 after implantation, p=0.01). Patients with severely dilated and overloaded ventricles who did not meet EVEREST II eligibility criteria were at higher risk of APS failure.

CONCLUSIONS

The failure of acute procedural success proved to have the most important impact on outcome after MitraClip implantation.

Percutaneous mitral valve edge-to-edge repair: in-hospital results and 1-year follow-up of 628 patients of the 2011-2012 Pilot European Sentinel Registry

BACKGROUND

The use of transcatheter mitral valve repair (TMVR) has gained widespread acceptance in Europe, but data on immediate success, safety, and long-term echocardiographic follow-up in real-world patients are still limited.

OBJECTIVES

The aim of this multinational registry is to present a real-world overview of TMVR use in Europe.

METHODS

The Transcatheter Valve Treatment Sentinel Pilot Registry is a prospective, independent, consecutive collection of individual patient data.

RESULTS

A total of 628 patients (mean age 74.2 ± 9.7 years, 63.1% men) underwent TMVR between January 2011 and December 2012 in 25 centers in 8 European countries. The prevalent pathogenesis was functional mitral regurgitation (FMR) (n = 452 [72.0%]). The majority of patients (85.5%) were highly symptomatic (New York Heart Association functional class III or higher), with a high logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) (20.4 ± 16.7%). Acute procedural success was high (95.4%) and similar in FMR and degenerative mitral regurgitation (p = 0.662). One clip was implanted in 61.4% of patients. In-hospital mortality was low (2.9%), without significant differences between groups. The estimated 1-year mortality was 15.3%, which was similar for FMR and degenerative mitral regurgitation. The estimated 1-year rate of rehospitalization because of heart failure was 22.8%, significantly higher in the FMR group (25.8% vs. 12.0%, p[log-rank] = 0.009). Paired echocardiographic data from the 1-year follow-up, available for 368 consecutive patients in 15 centers, showed a persistent reduction in the degree of mitral regurgitation at 1 year (6.0% of patients with severe mitral regurgitation).

CONCLUSIONS

This independent, contemporary registry shows that TMVR is associated with high immediate success, low complication rates, and sustained 1-year reduction of the severity of mitral regurgitation and improvement of clinical symptoms.

A Canadian cost-effectiveness analysis of transcatheter mitral valve repair with the MitraClip system in high surgical risk patients with significant mitral regurgitation

OBJECTIVE

In patients with significant mitral regurgitation (MR) at high risk of mortality and morbidity from mitral valve surgery, transcatheter mitral valve repair with the MitraClip System is associated with a reduction in MR and improved quality-of-life and functional status compared with baseline. The objective was to evaluate the cost-effectiveness of MitraClip therapy compared with standard of care in patients with significant MR at high risk for mitral valve surgery from a Canadian payer perspective.

METHODS

A decision analytic model was developed to estimate the lifetime costs, life years, quality-adjusted life years (QALYs), and incremental cost per life year and QALY gained for patients receiving MitraClip therapy compared with standard of care. Treatment-specific overall survival, risk of clinical events, quality-of-life, and resource utilization were obtained from the Endovascular Valve Edge-to-Edge REpair High Risk Study (EVEREST II HRS). Health utility and unit costs (CAD $2013) were taken from the published literature. Sensitivity analyses were conducted to explore the impact of alternative assumptions and parameter uncertainty on results.

RESULTS

The base case incremental cost per QALY gained was $23,433. RESULTS were most sensitive to alternative assumptions regarding overall survival, time horizon, and risk of hospitalization for congestive heart failure (CHF). Probabilistic sensitivity analysis showed MitraClip therapy to have a 92% chance of being cost-effective compared with standard of care at a willingness-to-pay threshold of $50,000 per QALY gained.

STUDY LIMITATIONS

Key limitations include the small number of patients included in the EVEREST II HRS which informed the analysis, the limited data available to inform clinical events and disease progression in the concurrent comparator group, and the lack of a comparator group from a randomized control trial.

CONCLUSION

MitraClip therapy is likely a cost-effective option for the treatment of patients at high risk for mitral valve surgery with significant MR.

Impact of the learning curve on outcome after transcatheter mitral valve repair: results from the German Mitral Valve Registry

AIMS

This analysis from the German Mitral Valve Registry investigates the impact of the learning curve with the MitraClip(®) technique on procedural success and complications.

METHODS AND RESULTS

Consecutive patients treated since 2009 in centers that performed more than 50 transcatheter mitral repairs were included. Results of the first half of the patients were compared to those of the second. Altogether 496 patients from 10 centers were included. Patients treated later had less common severe heart failure symptoms (patients with NYHA IV: 22.1 vs. 14.5 %, p < 0.05). The EuroSCORE I (22.0 vs. 23.0 %, p = ns) and Society of Thoracic Surgeons (STS) score (7.5 vs. 9.5 %, p = ns) did not differ between both groups. Procedural success was 95.6 % (238/249) in the first cases and 94.7 % (232/245, p = ns) subsequently. Also procedural time (104.3 vs. 119 min, p = ns) and complications did not decrease over time.

CONCLUSION

A learning curve using the MitraClip(®) device does not appear to significantly affect acute MR reduction, hospital and 30-day mortality. Most likely, the proctor system leads to already high initial procedure success and relatively short procedure time.