Outcome of mitral valve repair or replacement: a comparison by propensity score analysis

Transcatheter Mitral Valve Repair for Degenerative Mitral Regurgitation

Importance

There are limited data on the outcomes of transcatheter edge-to-edge mitral valve repair for degenerative mitral regurgitation (MR) in a real-world setting.

Objective

To evaluate the outcomes of transcatheter mitral valve repair for degenerative MR.

Design, Setting, and Participants

Cohort study of consecutive patients in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapies Registry who underwent nonemergent transcatheter mitral valve repair for degenerative MR in the US from 2014 through 2022.

Exposure

Transcatheter edge-to-edge mitral valve repair with the MitraClip device (Abbott).

Main Outcomes and Measures

The primary end point was MR success, defined as moderate or less residual MR and a mean mitral gradient of less than 10 mm Hg. Clinical outcomes were evaluated based on the degree of residual MR (mild or less MR or moderate MR) and mitral valve gradients (≤5 mm Hg or >5 to <10 mm Hg).

Results

A total of 19 088 patients with isolated moderate to severe or severe degenerative MR who underwent transcatheter mitral valve repair were analyzed (median age, 82 years; 48% women; median Society of Thoracic Surgeons predicted risk of mortality with surgical mitral valve repair, 4.6%). MR success was achieved in 88.9% of patients. At 30 days, the incidence of death was 2.7%; stroke, 1.2%; and mitral valve reintervention, 0.97%. MR success compared with an unsuccessful procedure was associated with significantly lower mortality (14.0% vs 26.7%; adjusted hazard ratio, 0.49; 95% CI, 0.42-0.56; P < .001) and heart failure readmission (8.4% vs 16.9%; adjusted hazard ratio, 0.47; 95% CI, 0.41-0.54; P < .001) at 1 year. Among patients with MR success, the lowest mortality was observed in patients who had both mild or less residual MR and mean mitral gradients of 5 mm Hg or less compared with those with an unsuccessful procedure (11.4% vs 26.7%; adjusted hazard ratio, 0.40; 95% CI, 0.34-0.47; P < .001).

Conclusions and Relevance

In this registry-based study of patients with degenerative MR undergoing transcatheter mitral valve repair, the procedure was safe and resulted in successful repair in 88.9% of patients. The lowest mortality was observed in patients with mild or less residual MR and low mitral gradients.

Machine Learning-Based Personalized Risk Prediction Model for Mortality of Patients Undergoing Mitral Valve Surgery: The PRIME Score

Background

Mitral valve surgery (MVS) is an effective treatment for mitral valve diseases. There is a lack of reliable personalized risk prediction models for mortality in patients undergoing mitral valve surgery. Our aim was to develop a risk stratification system to predict all-cause mortality in patients after mitral valve surgery.

Methods

Different machine learning models for the prediction of all-cause mortality were trained on a derivation cohort of 1,883 patients undergoing mitral valve surgery [split into a training cohort (70%) and internal validation cohort (30%)] to predict all-cause mortality. Forty-five clinical variables routinely evaluated at discharge were used to train the models. The best performance model (PRIME score) was tested in an externally validated cohort of 220 patients undergoing mitral valve surgery. The model performance was evaluated according to the area under the curve (AUC). Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were compared with existing risk strategies.

Results

After a median follow-up of 2 years, there were 133 (7.063%) deaths in the derivation cohort and 17 (7.727%) deaths in the validation cohort. The PRIME score showed an AUC of 0.902 (95% confidence interval [CI], 0.849–0.956) in the internal validation cohort and 0.873 (95% CI: 0.769–0.977) in the external validation cohort. In the external validation cohort, the performance of the PRIME score was significantly improved compared with that of the existing EuroSCORE II (NRI = 0.550, [95% CI 0.001–1.099], P = 0.049, IDI = 0.485, [95% CI 0.230–0.741], P < 0.001).

Conclusion

Machine learning-based model (the PRIME score) that integrate clinical, demographic, imaging, and laboratory features demonstrated superior performance for the prediction of mortality patients after mitral valve surgery compared with the traditional risk model EuroSCORE II.

Clinical Trial Registration

[http://www.clinicaltrials.gov], identifier [NCT05141292].

Evaluation of an Innovative Device for Mitral Valve Regurgitation: Experimental Acute In Vivo Results

OBJECTIVE

Currently, mitral prosthetic rings are intended only to reshape the annulus. We present in vivo results of an innovative device characterized by an intraventricular segment designed to enable artificial chordae implantation and simplify leaflets and subvalvular apparatus correction. Methods: Eight sheep were employed. The first 4 underwent solely device implantation. In the last 4, primary chordae of the anterior leaflet (A2) were torn to induce severe mitral regurgitation. The severed chordae were replaced by 2 pairs of 5-0 Gore-Tex artificial chordae previously measured and anchored to the device bridge. Ease of device and chordae implantation were evaluated, and postprocedural valve competence was verified by postoperative echocardiogram. Results: The procedure was completed in all 8 sheep. In the 4 sheep with induced severe mitral regurgitation, repair could be achieved by means of artificial chordae implantation. Length of the 2 chordae implanted was 21.6 ± 2 mm and 22 ± 3 mm, respectively. The time required to suture the artificial chordae was 2.5 ± 1.2 min. Postoperative echocardiograms showed normal left ventricular ejection fraction and free motion of the mitral leaflets. Mitral regurgitation was absent in 5 cases and trivial in 3. The transvalvular peak pressure gradient was 9.5 ± 6 mm Hg, and mean gradient was 3.7 ± 4 mm Hg. Postprocedural evaluation of the heart and mitral valve showed no damage to the left ventricle wall, valve leaflets, chordae, and papillary muscles. Conclusions: In vivo tests confirm safety of the device, ease of chordal length estimation prior to implantation, short operative time, and no negative impact of the device on mitral leaflet motion, function, and structure.

A new device to treat mitral valve regurgitation: a proof of concept in bench test study

Mitral valve repair is typically performed by implanting a ring-like device at the valve annulus to reshape the annulus and to improve leaflet coaptation. In most cases, some additional procedures are needed, including leaflet resection and artificial chordae implantation. However, artificial chordae implantation could be technically challenging and postoperative left ventricular remodeling could increase the risk of recurrent mitral regurgitation. We propose an innovative annular device made of chromo-cobalt, finalized not only to reshape the annulus but also to enable anchoring of leaflets to a fixed intraventricular structure. Durability evaluation of the device was tested by applying eight radial force vectors equally spaced along the ring and related fatigue analysis. To evaluate the efficacy of the mitral valvuloplasty using the tested ring, the device was implanted in five adult swine hearts. Functional analysis of the ring was performed by measuring left ventricular pressure and fluid volume loss, following implantation in normal and dysfunctional mitral valve leaflets. Both fatigue and functional analysis showed satisfactory and promising results in terms of durability and efficacy of mitral valve repair. Because of its favorable durability and functional characteristics this device appears promising and provides good results in terms of valve competence, thus avoiding both manipulations of papillary muscles and interference in left ventricular hemodynamics. However, an in vivo test is mandatory to fully understand the impact of the device on subvalvular apparatus.

Transcatheter mitral valve chord repair

The field of mitral valve disease diagnosis and management is rapidly evolving. New understanding of pathophysiology and improvements in the adoption of sophisticated multimodality imaging modalities have led to early diagnosis and to more complex treatment. The most common cause of mitral regurgitation (MR) in the western world is in the primary alteration of the valve, which leads to degenerative leaflet prolapse due to chordal elongation or rupture and annular dilatation. Untreated, significant MR has a negative impact prognosis, leading to reduction of survival. In the setting of degenerative MR, surgical repair currently represents the standard of care. Treatment of asymptomatic patients with severe MR in the Valve Center of Excellence, in which successful repair reaches more than 95% and surgical mortality less than 1%, symbolizes the direction for the next years. Transcatheter mitral valve repair with different devices, more recently the chordal replacement ones, is providing good outcomes and became a therapeutic option in high-risk patients with degenerative MR. In the future, more advances are expected from further development of interventional techniques, careful evaluation and better patient selection. This review will focus on long-term surgical outcomes of mitral valve repair with artificial chordae and on the emerging transcatheter chordal repair devices as therapeutic options for degenerative MR patients.

Mitral Valve Repair Versus Replacement in Elderly With Degenerative Disease: Analysis of the STS Adult Cardiac Surgery Database

BACKGROUND

It has been postulated that mitral valve repair in the elderly does not confer short-term benefits over mitral valve replacement with complete preservation of the chordal apparatus. Our purpose was to test this hypothesis using data from The Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS ACSD).

METHODS

Patients aged 70 years or more undergoing primary isolated elective mitral valve repair or mitral valve replacement for degenerative disease were obtained from the STS ACSD versions 2.73 and 2.81. Patients with a concomitant tricuspid procedure, atrial fibrillation surgery, or atrial septal defect/patent foramen ovale repair were included. The two treatment groups were further stratified by age in years (70 to 74, 75 to 79, and 80 or more). Adjusted 30-day mortality rates were analyzed by mitral procedure and chordal preservation strategy.

RESULTS

The study included 12,043 patients, of whom 71% underwent mitral valve repair. Observed 30-day mortality after repair was lower than after replacement (2.2% versus 4.8%, respectively; p < 0.0001). Using repair as reference, adjusted operative mortality was higher for replacement in the overall cohort (odds ratio 1.83, 95% confidence interval: 1.45 to 2.31). There was no significant difference in mortality between complete versus partial chordal preservation in repair (odds ratio 1.24, 95% confidence interval: 0.80 to 1.93). Mitral valve replacement with chordal preservation remained inferior to repair (odds ratio 1.66, 95% confidence interval: 1.28 to 2.14). The failed repair rate was 7.9%, with a 30-day mortality of 6%.

CONCLUSIONS

In patients aged 70 years or more, degenerative mitral repair was associated with lower operative mortality compared with replacement, irrespective of chordal preservation strategy. Failed repairs reduced this short-term benefit compared with chordal-sparing replacement as evidenced by the similar operative mortality on an intention to treat analysis.

Antithrombotic therapy after mitral valve repair: VKA or aspirin?

The optimal antithrombotic therapy following mitral valve repair (MVr) is still a matter of debate. Therefore, we evaluated the rate of thromboembolic and bleeding complications of two antithrombotic prevention strategies: vitamin K antagonists (VKA) versus aspirin. Consecutive patients who underwent MVr between 2004 and 2016 at three Dutch hospitals were evaluated for thromboembolic and bleeding complications during three postoperative months. The primary endpoint was the combined incidence of thromboembolic and bleeding complications to determine the net clinical benefit of VKA strategy as compared with aspirin. Secondary objectives were to evaluate both thromboembolic and bleeding rates separately and to identify predictors for both complications. A total of 469 patients were analyzed, of whom 325 patients (69%) in the VKA group and 144 patients (31%) in the aspirin group. Three months postoperatively, the cumulative incidence of the combined end point of the study was 9.2% (95%CI 6.1-12) in the VKA group and 11% (95%CI 6.0-17) in the aspirin group [adjusted hazard ratio (HR) 1.6, 95%CI 0.83-3.1]. Moreover, no significant differences were observed in thromboembolic rates (adjusted HR 0.82, 95%CI 0.16-4.2) as well as in major bleeding rates (adjusted HR 1.89, 95%CI 0.90-3.9). VKA and aspirin therapy showed a similar event rate of 10% during 3 months after MVr in patients without prior history of AF. In both treatment groups thromboembolic event rate was low and major bleeding rates were comparable. Future prospective, randomized trials are warranted to corroborate our findings.

Dynamic Patient-Specific Three-Dimensional Simulation of Mitral Repair

Objective

Planned mitral repair strategies are generally established from preoperative echocardiography; however, specific details of the repair are often determined intraoperatively. We propose that three-dimensional printed, patient-specific, dynamic mitral valve models may help surgeons plan and trial all the details of a specific patient's mitral repair preoperatively.

Methods

Using preoperative echocardiography, segmentation, modeling software, and three-dimensional printing, we created dynamic, high-fidelity, patient-specific mitral valve models including the subvalvular apparatus. We assessed the accuracy of 10 patient mitral valve models anatomically and functionally in a heart phantom simulator, both objectively by blinded echocardiographic assessment, and subjectively by two mitral repair experts. After this, we attempted model mitral repair and compared the outcomes with postoperative echocardiography.

Results

Model measurements were accurate when compared with patients on anterior-posterior diameter, circumference, and anterior leaflet length; however, less accurate on posterior leaflet length. On subjective assessment, Likert scores were high at 3.8 ± 0.4 and 3.4 ± 0.7, suggesting good fidelity of the dynamic model echocardiogram and functional model in the phantom to the preoperative three-dimensional echocardiogram, respectively. Mitral repair was successful in all 10 models with significant reduction in mitral insufficiency. In two models, mitral repair was performed twice, using two different surgical techniques to assess which provided a better outcome. When compared with the actual patient mitral repair outcome, the repaired models compared favorably.

Conclusions

Complex mitral valve modeling seems to predict an individual patient's mitral anatomy well, before surgery. Further investigation is required to determine whether deliberate preoperative practice can improve mitral repair outcomes.

Outcomes after mitral valve surgery for rheumatic heart disease

Objective

To further the understanding of the factors influencing outcome following rheumatic heart disease (RHD) related mitral valve surgery, which globally remains an important cause of heart disease and a particular problem in Indigenous Australians.

Methods

The Australian Cardiac Surgery Database was utilised to assess outcomes following mitral valve repair and replacement for RHD and non-RHD valve disease. The association with aetiology, demographics, comorbidities, preoperative status and operative procedure was evaluated.

Results

Mitral valve repairs and replacements undertaken in Australia were analysed from 119 and 1078 RHD surgical procedures and 3279 and 2400 non-RHD procedures, respectively. RHD mitral valve repair, compared with replacement, resulted in a slightly shorter hospital stay and more reoperation for valve dysfunction, but no difference in 30-day survival. In unadjusted survival analysis to 5 years, RHD mitral valve repair and replacement were no different (HR 0.86, 95% CI 0.4 to 1.7), non-RHD repair was superior to replacement (HR 1.7, 95% CI 1.4 to 2.0), RHD and non-RHD repair were no different (HR 0.9, 95% CI 0.5 to 1.7), and RHD replacement was superior to non-RHD (HR 1.5, 95% CI 1.2 to 1.9). None of these differences persisted in adjusted analyses and there was no difference in long-term survival for Indigenous Australians.

Conclusion

In this large prospective cohort study we have demonstrated that adjusted long-term survival following RHD mitral valve repair surgery in Australia is no different to replacement and no different to non-RHD. Interpretation of valve surgery outcome requires careful consideration of patient factors that may also influence survival.

Primary mitral valve regurgitation: Update and review

Mitral regurgitation is the second most common valvular disorder requiring surgical intervention worldwide. This review summarizes the current understanding of primary, degenerative mitral regurgitation with respect to etiology, comprehensive assessment, natural history and management. The new concept of staging of the valvular disorders, newer predictors of adverse and controversy of “watchful waiting” versus “early surgical intervention” for severe, asymptomatic, primary mitral regurgitation are addressed.

Surgery for rheumatic mitral valve disease in sub-saharan African countries: why valve repair is still the best surgical option

Rheumatic valve disease, a consequence of acute rheumatic fever, remains endemic in developing countries in the sub-Saharan region where it is the leading cause of heart failure and cardiovascular death, involving predominantly a young population. The involvement of the mitral valve is pathognomonic and mitral surgery has become the lone therapeutic option for the majority of these patients. However, controversies exist on the choice between valve repair or prosthetic valve replacement. Although the advantages of mitral valve repair over prosthetic valve replacement in degenerative mitral disease are well established, this has not been the case for rheumatic lesions, where the use of prosthetic valves, specifically mechanical devices, even in poorly compliant populations remains very common. These patients deserve more accurate evaluation in the choice of the surgical strategy which strongly impacts the post-operative outcomes. This report discusses the factors supporting mitral repair surgery in rheumatic disease, according to the patients' characteristics and the effectiveness of the current repair techniques compared to prosthetic valve replacement in developing countries.

Neochord placement versus triangular resection in mitral valve repair: A finite element model

BACKGROUND

Recurrent mitral regurgitation after mitral valve repair is common, occurring in nearly 50% of patients within 10 years of surgery. Durability of repair is partly related to stress distribution over the mitral leaflets. We hypothesized that repair with neochords (NCs) results in lower stress than leaflet resection (LR).

MATERIALS AND METHODS

Magnetic resonance imaging and 3D echocardiography were performed before surgical repair of P2 prolapse in a single patient. A finite element model of the left ventricle and mitral valve was created previously, and the modeling program LS-DYNA was used to calculate leaflet stress for the following repairs: Triangular LR; LR with ring annuloplasty (LR + RA); One NC; Two NCs; and 2NC + RA.

RESULTS

(1) NC placement resulted in stable posterior leaflet stress: Baseline versus 2 NC at end diastole (ED), 12.1 versus 12.0 kPa, at end systole (ES) 20.3 versus 21.7 kPa. (2) In contrast, LR increased posterior leaflet stress: Baseline versus LR at ED 12.1 versus 40.8 kPa, at ES 20.3 versus 46.1 kPa. (3) All repair types reduced anterior leaflet stress: Baseline versus 2 NC versus LR 34.2 versus 25.8 versus 20.6 kPa at ED and 80.8 versus 76.8 versus 67.8 kPa at ES. (4) The addition of RA reduced leaflet stress relative to repair without RA.

CONCLUSIONS

Neochord repair restored normal leaflet coaptation without creating excessive leaflet stress, whereas leaflet resection more than doubled stress across the posterior leaflet. The excess stress created by leaflet resection was partially, but not completely, mitigated by ring annuloplasty.

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.

Agreement of treatment effects for mortality from routinely collected data and subsequent randomized trials: meta-epidemiological survey

OBJECTIVE

To assess differences in estimated treatment effects for mortality between observational studies with routinely collected health data (RCD; that are published before trials are available) and subsequent evidence from randomized controlled trials on the same clinical question.

DESIGN

Meta-epidemiological survey.

DATA SOURCES

PubMed searched up to November 2014.

METHODS

Eligible RCD studies were published up to 2010 that used propensity scores to address confounding bias and reported comparative effects of interventions for mortality. The analysis included only RCD studies conducted before any trial was published on the same topic. The direction of treatment effects, confidence intervals, and effect sizes (odds ratios) were compared between RCD studies and randomized controlled trials. The relative odds ratio (that is, the summary odds ratio of trial(s) divided by the RCD study estimate) and the summary relative odds ratio were calculated across all pairs of RCD studies and trials. A summary relative odds ratio greater than one indicates that RCD studies gave more favorable mortality results.

RESULTS

The evaluation included 16 eligible RCD studies, and 36 subsequent published randomized controlled trials investigating the same clinical questions (with 17,275 patients and 835 deaths). Trials were published a median of three years after the corresponding RCD study. For five (31%) of the 16 clinical questions, the direction of treatment effects differed between RCD studies and trials. Confidence intervals in nine (56%) RCD studies did not include the RCT effect estimate. Overall, RCD studies showed significantly more favorable mortality estimates by 31% than subsequent trials (summary relative odds ratio 1.31 (95% confidence interval 1.03 to 1.65; I(2)=0%)).

CONCLUSIONS

Studies of routinely collected health data could give different answers from subsequent randomized controlled trials on the same clinical questions, and may substantially overestimate treatment effects. Caution is needed to prevent misguided clinical decision making.

Repair or replace for severe ischemic mitral regurgitation: prospective randomized multicenter data

Ischemic mitral regurgitation (IMR) is a subset of functional mitral regurgitation (MR) that has the potential to impact an increasing number of patients in the future. This is in the context of a worldwide population, which continues to live longer with improved survival after myocardial infarction. Substantial data have accumulated over the past few decades demonstrating the negative effects of IMR. Further, significant research has been done to define the optimal surgical approach and several studies have compared mitral repair versus replacement for patients with severe mitral regurgitation (SMR). Studies supporting performance of mitral repair cite superior operative morbidity and mortality rates, while proponents of mitral replacement cite improved long-term durability and correction of MR. Lack of clinically robust Level I randomized controlled trial data have curtailed attempts to better define appropriate surgical treatment allocation over the past few decades. Recently, however, the Cardiothoracic Surgical Trials Network (CTSN) conducted the first randomized controlled trial, funded by the National Heart, Lung, and Blood Institute, the National Institute for Neurological Diseases and Stroke and the Canadian Institute for Health Research, to compare the performance of mitral repair versus replacement for SMR. Herein, the present review describes the design, results and implications of the CTSN SMR trial and its efforts to identify the most efficacious surgical approach to SMR. This review also describes CTSN investigation to predict the recurrence of MR after mitral repair.

A mitral annulus tracking approach for navigation of off-pump beating heart mitral valve repair

PURPOSE

To develop and validate a real-time mitral valve annulus (MVA) tracking approach based on biplane transesophageal echocardiogram (TEE) data and magnetic tracking systems (MTS) to be used in minimally invasive off-pump beating heart mitral valve repair (MVR).

METHODS

The authors' guidance system consists of three major components: TEE, magnetic tracking system, and an image guidance software platform. TEE provides real-time intraoperative images to show the cardiac motion and intracardiac surgical tools. The magnetic tracking system tracks the TEE probe and the surgical tools. The software platform integrates the TEE image planes and the virtual model of the tools and the MVA model on the screen. The authors' MVA tracking approach, which aims to update the MVA model in near real-time, comprises of three steps: image based gating, predictive reinitialization, and registration based MVA tracking. The image based gating step uses a small patch centered at each MVA point in the TEE images to identify images at optimal cardiac phases for updating the position of the MVA. The predictive reinitialization step uses the position and orientation of the TEE probe provided by the magnetic tracking system to predict the position of the MVA points in the TEE images and uses them for the initialization of the registration component. The registration based MVA tracking step aims to locate the MVA points in the images selected by the image based gating component by performing image based registration.

RESULTS

The validation of the MVA tracking approach was performed in a phantom study and a retrospective study on porcine data. In the phantom study, controlled translations were applied to the phantom and the tracked MVA was compared to its "true" position estimated based on a magnetic sensor attached to the phantom. The MVA tracking accuracy was 1.29 ± 0.58 mm when the translation distance is about 1 cm, and increased to 2.85 ± 1.19 mm when the translation distance is about 3 cm. In the study on porcine data, the authors compared the tracked MVA to a manually segmented MVA. The overall accuracy is 2.37 ± 1.67 mm for single plane images and 2.35 ± 1.55 mm for biplane images. The interoperator variation in manual segmentation was 2.32 ± 1.24 mm for single plane images and 1.73 ± 1.18 mm for biplane images. The computational efficiency of the algorithm on a desktop computer with an Intel(®) Xeon(®) CPU @3.47 GHz and an NVIDIA GeForce 690 graphic card is such that the time required for registering four MVA points was about 60 ms.

CONCLUSIONS

The authors developed a rapid MVA tracking algorithm for use in the guidance of off-pump beating heart transapical mitral valve repair. This approach uses 2D biplane TEE images and was tested on a dynamic heart phantom and interventional porcine image data. Results regarding the accuracy and efficiency of the authors' MVA tracking algorithm are promising, and fulfill the requirements for surgical navigation.

Review of mitral valve insufficiency: repair or replacement

Mitral valve (MV) dysfunction is the second-most common clinically significant form of valvular defect in adults. MV regurgitation occurs with the increasing frequency of degenerative changes of the aging process. Moreover, other causes of clinically significant MV regurgitation include cardiac ischemia, infective endocarditis and rhematic disease more frequently in less developed countries. Recent evidence suggests that the best outcomes after repair of severe degenerative mitral regurgitation (MR) are achieved in asymptomatic or minimally symptomatic patients, who are selected for surgery soon after diagnosis on the basis of echocardiography. This review will focus on the surgical management of mitral insufficiency according to its aetiology today and will give insight to some of the perspectives that lay in the future.

Using a shape prior for robust modeling of the mitral annulus on 4D ultrasound data

PURPOSE

Over 40,000 annuloplasty rings are implanted each year in the USA to treat mitral regurgitation. However, the used measuring techniques to select a suitable annuloplasty ring are imprecise and highly depending on the expert's experience. This can cause a re-occurrence of the mitral regurgitation or an annuloplasty ring dehiscence, and thus the necessity of a re-operation. We propose a method to create a 4D model of the mitral annulus from ultrasound data to enable precise measurement and patient-specific implant planning.

METHODS

An initial mitral annulus model is placed interactively in the 4D image data by defining commissure points and the annulus plane for one time step in diastole and systole. The model is automatically optimized using distinct image features. A shape and pose prior of the mitral annulus is used to compensate for artifacts and to enforce a plausible anatomical morphology, while a temporal alignment ensures a natural motion of the 4D model.

RESULTS

Ground truth data were created for 4D images of 42 patients with varying image quality. A parameter and shape prior training was performed on a third of the ground truth data, while the rest was used to validate the method. The average error of the resulting mitral annulus models was computed as 2.25 ( +/-0.38 ) mm. The average expert standard deviation was determined as 1.86 (+/-0.32 ) mm.

CONCLUSION

The proposed method enables the 4D modeling of mitral annuli based on ultrasound data in less than 2 min. The resulting models are comparable to manually delineated models and can be used for measurements of annular geometries and patient-specific annuloplasty treatment planning.

Intraoperative evaluation of transmitral pressure gradients after edge-to-edge mitral valve repair

Objective

Edge-to-edge repair of the mitral valve (MV) has been described as a viable option used for the surgical management of mitral regurgitation (MR). Based on the significant changes in MV geometry associated with this technique, we hypothesized that edge-to-edge MV repairs are associated with higher intraoperative transmitral pressure gradients (TMPG) compared to conventional methods.

Methods

Patient records and intraoperative transesophageal echocardiography (TEE) examinations of 552 consecutive patients undergoing MV repair at a single institution over a three year period were assessed. After separation from cardiopulmonary bypass (CPB), peak and mean TMPG were recorded for each patient and subsequently analyzed.

Results

84 patients (15%) underwent edge-to-edge MV repair. Peak and mean TMPG were significantly higher compared to gradients in patients undergoing conventional repairs: 10.7±0.5 mmHg vs 7.1±0.2 mmHg; P<0.0001 and 4.3±0.2 mmHg vs 2.8±0.1 mmHg; P<0.0001. Only patients with mean TMPG ≥7 mmHg (n = 9) required prompt reoperation for iatrogenic mitral stenosis (MS). No differences in peak and mean TMPG were observed among edge-to-edge repairs performed in isolation, compared to those performed in combination with annuloplasty: 11.0±0.7 mmHg vs 10.3±0.6 mmHg and 4.4±0.3 mmHg vs 4.3±0.3 mmHg. There were no differences in TMPG between various types of annuloplasty techniques used in combination with the edge-to-edge repairs.

Conclusions

Edge-to-edge MV repairs are associated with higher intraoperative peak and mean TMPG after separation from CPB compared to conventional repair techniques. Unless gradients are severely elevated, these findings are not necessarily suggestive of iatrogenic MS. Thus, in the immediate postoperative period mildly elevated TMPG can be expected and tolerated after edge-to-edge mitral repairs.

Outcome of mitral valve plasty or replacement: atrial fibrillation an effect modifier

BACKGROUND

Advances in the understanding of mitral valve pathology have laid to mitral valve plasty (MPL) as the procedure of choice of all the mitral intervention as compared to mitral valve replacement (MVR).

MATERIAL AND METHODS

A cohort of 355 patients with mitral valve disease operated between January 1993 to January 2007 with closing date first of mars 2011. There were 214 MPL and 141 MVR at the Hospital discharge. This retrospective cohort had the design of exposed (MPL) versus non-exposed (MVR) with outcome total mortality and reoperation during follow up. Also echocardiography follow-up was undertaken to estimate the true long-term failure rate of repair.

RESULTS

The mean follow up was 5.3 years SE (3.82) maximum follow up was 14.1 years. Considering the patient time model the association between repair/replacement and total mortality RR = 0.43 95% (0.28-074) p = 0.002 controlling for the confounding effect of 3-vessels disease. Those results were confirmed by propensity score analysis.

CONCLUSION

In a cohort of patient with mitral valve disease undergoing MPL/MVR was examined. MPL was associated with better survival, and lower reoperation rate for patients without AF but same rate for patients with AF. We advocate more attention in controlling risk factors of AF in the clinical management of mitral disease. Long-term failure rate of MPL was low during follow up time. A replication of our results by a randomized clinical trial is mandatory.

Fast Simulation of Mitral Annuloplasty for Surgical Planning

Mitral valve repair is a complex procedure that requires the ability to predict closed valve shape through the examination of an unpressurized, accid valve. These procedures typically include the remodeling of the mitral annulus through the insertion of an annuloplasty ring. While simulations could facilitate the planning of the procedure, traditional finite-element models of mitral annuloplasty are too slow to be clinically feasible and have never been validated in tissue. This work presents a fast method for simulating valve closure post-annuloplasty using a mass-spring tissue model and subject-specific valve geometry. Closed valve shape is predicted in less than one second. The results are validated by implanting an annuloplasty ring in an excised porcine heart and comparing simulated to imaged results. Results indicate that not only can mitral annuloplasty be simulated quickly, but also with submillimeter accuracy.

Changes in left ventricular morphology and function after mitral valve surgery

Degenerative mitral valve disease is the leading cause of mitral regurgitation in North America. Surgical intervention has hinged on the symptoms and ventricular changes that develop as compensatory ventricular remodeling occurs. In the present study, we sought to characterize the temporal response of left ventricular (LV) morphology and function to mitral valve surgery for degenerative disease and to identify the preoperative factors that influence reverse remodeling. From 1986 to 2007, 2,778 patients with isolated degenerative mitral valve disease underwent valve repair (n = 2,607 [94%]) or replacement (n = 171 [6%]) and had ≥1 postoperative transthoracic echocardiogram; 5,336 transthoracic echocardiograms were available for analysis. Multivariate longitudinal repeated-measures analysis was performed to identify the factors associated with reverse remodeling. The LV dimensions decreased in the first year after surgery (end-diastolic from 5.7 ± 0.80 to 4.9 ± 1.4 cm; end-systolic from 3.4 ± 0.71 to 3.1 ± 1.4 cm). The LV mass index decreased from 139 ± 44 to 112 ± 73 g/m(2). The reduction in LV hypertrophy was less pronounced in patients with greater preoperative left heart enlargement (p <0.0001) and a greater preoperative LV mass (p <0.0001). The postoperative LV ejection fraction initially decreased from 58 ± 7.0% to 53 ± 20%, increased slightly during the first postoperative year, and was negatively influenced by preoperative heart failure symptoms (p <0.0001) and a lower preoperative LV ejection fraction (p <0.0001). The risk-adjusted response of LV morphology and function to valve repair and replacement was similar (p >0.2). In conclusion, a positive response toward normalization of LV morphology and function after mitral valve surgery is greatest in the first year. The best response occurs when surgery is performed before left heart dilation, LV hypertrophy, or LV dysfunction develop.

Predictors of outcome of non-ischemic mitral valve surgery

BACKGROUND

Data on the risk stratification of patients undergoing mitral valve (MV) surgery for non-ischemic mitral disease are sparse. The present study seeks to define them in a contemporary cohort.

METHODS

193 consecutive patients referred to non-ischemic MV surgery were prospectively studied. Baseline characteristics and the type of surgery were analyzed with regard to operative and late mortality as well as functional outcome.

RESULTS

129 patients underwent MV replacement and 64 MV repair. MV replacement patients presented with more symptoms (p = 0.010), higher EuroSCORE (6.1 versus 5.6; p=0.009), more frequently underwent additional valve surgery (7.8 versus 0%; p = 0.003) and were more frequently female (p=0.048). Operative mortality was 3.1%, two thirds of operative deaths had additional surgery of the tricuspid valve (p = 0.019). Patients were followed for 5.2 ± 2.7 years. 1-, 3-, 5- and 7-year survival rates were 93-, 91-, 82-, and 79% in MV replacement patients versus 100-, 98-, 96-, and 89% in patients with MV repair (p = 0.015). However, by multivariate logistic regression, overall mortality was determined by additional surgery of the tricuspid valve (p = 0.0103), multivessel coronary disease (p = 0.026), and age (p<0.0001), but not by the type of surgery (p=0.066). Furthermore, the type of surgery did not influence functional outcome (p = 0.515).

CONCLUSIONS

Apart from age and coronary artery disease the need for additional tricuspid valve surgery significantly determines the outcome of non-ischemic MV surgery. The type of operation appears less important when the need for additional valve surgery and co-morbidities like coronary artery disease are taken into consideration.

Postoperative Functional Outcome After Off-Pump Versus On-Pump Coronary Artery Bypass Grafting Using Gated Myocardial SPECT: A Comparison by Propensity Score Analysis

PURPOSE

We evaluated the short-term and mid-term differences in perfusion and function after off-pump and on-pump coronary artery bypass grafting (CABG) using gated myocardial single photon emission computed tomography.

MATERIALS AND METHODS

A total of 70 patients with coronary artery disease who underwent CABG were included based on the propensity score matching results from 165 patients. Thirty-five patients underwent off-pump and 35 patients on-pump CABG. Rest (201)Tl/dipyridamole stress (99 m)Tc-methoxyisobutylisonitrile gated single photon emission computed tomographies were performed preoperatively and postoperatively at short-term (103 ± 23 days after surgery) and mid-term follow-up (502 ± 111 days after surgery). Changes in left ventricular ejection fraction, end systolic volume, stress and rest segmental perfusion, and segmental wall thickening were compared between the two groups. The segments with preoperative rest (201)Tl uptake under 60% of maximum uptake were included in the segmental analysis.

RESULTS

Left ventricular ejection fraction (P = 0.001) and end systolic volume (P = 0.008) showed significant improvement in both groups. There were no significant short-term and mid-term differences between the two groups in terms of left ventricular ejection fraction (P = 0.309) and end systolic volume (P = 0.938). Likewise, segmental rest (P = 0.178) and stress perfusion (P = 0.071), and systolic wall thickening (P = 0.241) showed significant improvement in both groups with similar time courses.

CONCLUSION

Off-pump CABG resulted in significant improvements in left ventricular ejection fraction, end systolic volume, and regional myocardial perfusion and function that are comparable to on-pump CABG at short-term and mid-term. Gated myocardial SPECT successfully revealed that off-pump CABG is as good as on-pump CABG from the viewpoint of myocardial perfusion and function.

Scale-up of a decentralized HIV treatment programme in rural KwaZulu-Natal, South Africa: does rapid expansion affect patient outcomes?

OBJECTIVE

To describe the scale-up of a decentralized HIV treatment programme delivered through the primary health care system in rural KwaZulu-Natal, South Africa, and to assess trends in baseline characteristics and outcomes in the study population.

METHODS

The programme started delivery of antiretroviral therapy (ART) in October 2004. Information on all patients initiated on ART was captured in the programme database and follow-up status was updated monthly. All adult patients (> or = 16 years) who initiated ART between October 2004 and September 2008 were included and stratified into 6-month groups. Clinical and sociodemographic characteristics were compared between the groups. Retention in care, mortality, loss to follow-up and virological outcomes were assessed at 12 months post-ART initiation.

FINDINGS

A total of 5719 adults initiated on ART were included (67.9% female). Median baseline CD4+ lymphocyte count was 116 cells/microl (interquartile range, IQR: 53-173). There was an increase in the proportion of women who initiated ART while pregnant but no change in other baseline characteristics over time. Overall retention in care at 12 months was 84.0% (95% confidence interval, CI: 82.6-85.3); 10.9% died (95% CI: 9.8-12.0); 3.7% were lost to follow-up (95% CI: 3.0-4.4). Mortality was highest in the first 3 months after ART initiation: 30.1 deaths per 100 person-years (95% CI: 26.3-34.5). At 12 months 23.0% had a detectable viral load (> 25 copies/ml) (95% CI: 19.5-25.5).

CONCLUSION

Outcomes were not affected by rapid expansion of this decentralized HIV treatment programme. The relatively high rates of detectable viral load highlight the need for further efforts to improve the quality of services.

Current surgical management of mitral regurgitation

From Walton Lillehei, who performed the first successful open mitral valve surgery in 1956, until the advent of robotic surgery in the 21st Century, only 50 years have passed. The introduction of the first heart valve prosthesis, in 1960, was the next major step forward. However, correction of mitral disease by valvuloplasty results in better survival and ventricular performance than mitral valve replacement. However, the European Heart Survey demonstrated that only 40% of the valves are repaired. The standard procedures (Carpentier's techniques and Alfieri's edge-to-edge suture) are the surgical basis for the new technical approaches. Minimally invasive surgery led to the development of video-assisted and robotic surgery and interventional cardiology is already making the first steps on endovascular procedures, using the classical concepts in highly differentiated approaches. Correction of mitral regurgitation is a complex field that is still growing, whereas classic surgery is still under debate as the new era arises.

A review of the application of propensity score methods yielded increasing use, advantages in specific settings, but not substantially different estimates compared with conventional multivariable methods

OBJECTIVE

Propensity score (PS) analyses attempt to control for confounding in nonexperimental studies by adjusting for the likelihood that a given patient is exposed. Such analyses have been proposed to address confounding by indication, but there is little empirical evidence that they achieve better control than conventional multivariate outcome modeling.

STUDY DESIGN AND METHODS

Using PubMed and Science Citation Index, we assessed the use of propensity scores over time and critically evaluated studies published through 2003.

RESULTS

Use of propensity scores increased from a total of 8 reports before 1998 to 71 in 2003. Most of the 177 published studies abstracted assessed medications (N=60) or surgical interventions (N=51), mainly in cardiology and cardiac surgery (N=90). Whether PS methods or conventional outcome models were used to control for confounding had little effect on results in those studies in which such comparison was possible. Only 9 of 69 studies (13%) had an effect estimate that differed by more than 20% from that obtained with a conventional outcome model in all PS analyses presented.

CONCLUSIONS

Publication of results based on propensity score methods has increased dramatically, but there is little evidence that these methods yield substantially different estimates compared with conventional multivariable methods.

Medical and surgical treatment of chronic mitral regurgitation

Chronic severe mitral regurgitation is a progressive disease that can lead to left ventricular dysfunction. New information on the natural history of the disease, along with advances in surgical techniques, has changed the roles of medical and surgical therapies. There is no well-defined role for medical therapy in chronic mitral regurgitation. The goal of the treating physician is therefore to identify the optimal timing for surgical intervention. The timing of surgical intervention depends primarily on two factors: (i) clinical symptoms and (ii) the left ventricular response to volume overload. However, the aetiology of mitral regurgitation, the likelihood of surgical repair, the occurrence of atrial fibrillation and the presence of pulmonary hypertension, together with the haemodynamic response to exercise, are important factors in the optimal surgical timing. New concepts in the understanding of the natural history of the disease coupled with success of mitral repair have recently resulted in a widespread evolution towards earlier surgery.

Percutaneous valve repair and replacement techniques

Valvular heart disease is a significant cause of morbidity and mortality. Rates increase with age and the prevalence will increase as the population ages. Several factors have led to an interest in expanding percutaneous valve repair and replacement techniques to more lesions in more patients. This review explores current percutaneous valve repair and replacement techniques in mitral stenosis, mitral regurgitation, aortic stenosis and aortic regurgitation in adults, outlines the future directions, and discusses some technique-related issues.

Mitral regurgitation: overview of current surgical techniques and future developments

Mitral regurgitation is a complex disease with many different etiologies, underlying dysfunctions and histologic alterations. Surgical correction of this condition dramatically improves the life expectancy and life quality of affected patients. The structure of the mitral valve lends itself to many surgical techniques. The purpose of this review is to offer readers an overview on this subject.

Does hospitalization impact survival after lower respiratory infection in nursing home residents?

BACKGROUND

Lower respiratory infection (LRI) is the leading cause of hospitalization for nursing home residents, but hospitalization is costly and may cause complications.

OBJECTIVE

We sought to compare mortality and cost between episodes of LRI initially treated in the hospital versus the nursing home after controlling for illness severity and the probability of hospitalization.

DESIGN

This was a prospective cohort study of nursing home residents with LRIs.

SUBJECTS

We identified 1406 episodes of LRI in 36 nursing homes in central Missouri and the St. Louis area between August 15, 1995, and September 30, 1998. Economic analysis was restricted to 1033 episodes identified after March 31, 1997.

MEASURES

We adjusted for the higher probability of initial hospitalization in sicker residents using measures of illness severity and a hospitalization propensity score. The propensity score was derived from a logistic regression model that included patient, physician, and facility variables. Estimated costs were attributed to initial treatment setting.

RESULTS

After controlling for the probability of hospitalization and illness severity, hospitalization was not a significant mortality predictor (odds ratio 0.89, 95% confidence interval 0.52-1.52). Mean daily cost was $138.24 for initial nursing home treatment and $419.75 for the hospital.

CONCLUSIONS

After controlling for illness severity and propensity for hospitalization, hospital treatment is not associated with either increased or decreased risk for mortality for nursing home residents with LRIs. For residents with low and medium mortality risk, nursing home treatment is likely to be safe and less costly.

Effects of Paracommissural Septal-Lateral Annular Cinching on Acute Ischemic Mitral Regurgitation

BACKGROUND

Previous experimental studies demonstrated that central septal-lateral (SL) annular cinching (SLAC) abolishes acute ischemic mitral regurgitation (IMR), but whether localized cinching near the anterior (ACOM) or posterior (PCOM) commissure is equally effective is unknown.

METHODS

Six adult sheep underwent implantation of 9 radiopaque markers on the left ventricle, 8 around the mitral annulus (MA) and 1 on each papillary muscle (PM) tip. Transannular SL sutures were placed at the valve center (CENT) and near ACOM and PCOM and externalized. Acute IMR was induced by proximal circumflex coronary snare occlusion. Biplane videofluoroscopy and transesophageal echocardiography were performed before and continuously during 3 episodes of myocardial ischemia including 20 seconds of SLAC at each different location. End-systolic MA SL dimension at each suture location and distances between the anterior and posterior PM tips and mid-septal annulus ("saddle horn") were calculated from the 3-dimensional (3D) marker coordinates.

RESULTS

SLAC interventions in all 3 locations reduced the degree of IMR, but cinching at the center, SLAC(CENT), had a significantly greater effect on reducing the magnitude of IMR than SLAC(PCOM) or SLAC(ACOM) (mean grade of IMR reduction=1.0+/-0.5, 1.8+/-0.5, and 0.9+/-0.2 for SLAC(ACOM), SLAC(CENT), and SLAC(PCOM), respectively; P=0.044). Although ACOM and PCOM cinching reduced SL(CENT) somewhat, only SLAC(CENT) simultaneously reduced both SL(ACOM) and SL(PCOM) and also repositioned both PM tips closer to the annular saddle horn.

CONCLUSIONS

SLAC in all 3 positions reduced acute IMR, but central SLAC cinching was most effective, reduced all mitral annular SL dimensions, and relocated both PM tips closer to the mid-septal annulus. Central SLAC is most capable of correcting the annular and subvalvular perturbations accompanying acute left ventricular ischemia that lead to IMR.