Incidence and outcomes of early percutaneous coronary intervention after isolated valve surgery.

BACKGROUND: Coronary ischemia requiring early percutaneous coronary intervention (PCI) is a rare but serious complication of isolated valve surgery. We sought of assess the incidence, predictors and outcomes of early PCI after isolated valve surgery using the national inpatient sample. METHODS: Patients who underwent isolated aortic valve replacement (AVR), isolated mitral valve repair (MVr) or replacement (MVR) between 2003 and 2014 were identified. Patients who had early postoperative PCI were compared with patients who did not require PCI. Primary end point was in-hospital mortality. Secondary endpoints were complications, length-of-stay and cost. RESULTS: Among the 135,611 included patients, 1,074 (0.8%) underwent PCI prior to discharge. Unadjusted in-hospital mortality was higher in patients requiring early PCI following AVR (11.2 vs. 3.1%), MVR (24.1 vs. 5.5%), and MVr (22.4 vs. 2.5%) (P < 0.001) compared with patients not requiring PCI. Postoperative PCI remained independently associated with higher mortality after adjusting for demographics, comorbidities and hospital characteristics (adjusted OR [aOR] = 3.74, 95%CI 2.70-5.17 for AVR, aOR = 6.10, 95%CI 4.53-8.23 for MVR, and aOR = 9.90, 95%CI 7.22-13.58 for MVr). Patients undergoing PCI had higher incidences of stroke, acute kidney injury, infectious complications, higher hospital charges, and longer hospitalizations. Age, robotic-assisted surgery, and chronic renal failure were independent predictors of needing early postoperative PCI. CONCLUSIONS: Early PCI after isolated aortic or mitral valve surgery is rare but is associated with substantial in-hospital morbidity, mortality, and cost. Further studies are needed to identify preventable causes, and optimal management strategies of this serious complication.

Simultaneous in- and out-of-plane Mitral Valve Annular Force Measurements.

Mitral valve repair with annuloplasty is often favoured over total valve replacement. In order to develop and optimize new annuloplasty ring designs, it is important to study the complex biomechanical behaviour of the valve annulus and the subvalvular apparatus with simultaneous in- and out-of-plane restraining force measurements. A new flat D-shaped mitral valve annular force transducer was developed. The transducer was mounted with strain gauges to measure strain and calibrated to provide simultaneous restraining forces in- and out of the mitral annular plane. The force transducer was implanted and evaluated in an 80 kg porcine experimental model. Accumulation of out-of-plane restraining forces, creating strain in the anterior segment were 0.7 ± 0.0 N (towards apex) and an average force accumulation of 1.5 ± 0.3 N, creating strain in the commissural segments (away from apex). The accumulations of in-plane restraining forces, creating strain on the inner side of the ring were 1.7 ± 0.2 N (away from ring center). A new mitral annular force transducer was successfully developed and evaluated in vivo. The transducer was able to measure forces simultaneously in different planes. Initial indications point towards overall agreement with previous individual force measurements in- and out-of the mitral annular plane. This can provide more detailed insight into the annular force distribution, and could potentially improve the level of evidence based mitral valve repair and support the development of future mitral annuloplasty devices.

Single-Center Experience With Adjustable Annuloplasty Ring in Degenerative Mitral Regurgitation.

OBJECTIVE: Owing to the complex anatomy of the mitral valve, successful surgical repair of degenerative regurgitation remains a challenging procedure in cardiac surgery. METHODS: This paper aimed to report on our single-center experience with 20 patients who received an adjustable annuloplasty ring (Cardinal ring, ValtechCardio Ltd, Or Yehuda, Israel) as part of their mitral valve repair procedure. The device allows for intraoperative echocardiography-guided ring size adjustments under beating-heart conditions. RESULTS: All of the 20 patients left the operating room without any residual mitral regurgitation. There was no risk of systolic anterior movement (SAM) because of image-guided fine tuning of the ring before weaning the patient from bypass. CONCLUSIONS: Further multicenter data are required to prove the concept of adjustable annuloplasty devices.

Assessment of mitral annuloplasty ring by cardiac computed tomography: Correlation with echocardiographic parameters and comparison between two different ring types.

OBJECTIVES: This study investigated computed tomographic (CT) appearance after mitral ring annuloplasty, especially comparing CT findings between patients with normal pressure gradient (PG) and patients with functional mitral stenosis (MS) and between 2 commonly used types of annuloplasty ring. METHODS: A total of 45 cardiac CT scans in patients who underwent mitral ring annuloplasty (Carpentier-Edwards ring, n = 27; Duran ring, n = 18) were retrospectively reviewed. On CT scan, presence of significant pannus around the annuloplasty ring, presence of leaflet thickening, and maximal mitral opening area were analyzed. CT findings were compared between patients with normal PG and patients with functional MS (mean diastolic PG ≥ 5 mm Hg). Incidences of functional MS and CT findings were compared between ring types. RESULTS: Significant pannus was present in 10 cases and leaflet thickening in 31 cases, and maximal opening area was 2.34 ± 0.717 cm(2). Valve opening area on CT was positively correlated with mitral valve area on transthoracic echocardiography and negatively correlated with mean diastolic PG. Mean diastolic PG was significantly elevated with increasing pannus severity. Patients with functional MS had more significant pannus than patients with normal PG. The Duran ring group had higher mean diastolic PG, smaller mitral valve area, and higher incidence of functional MS than the Carpentier-Edwards ring group (P < .05). The proportion of pannus and significant pannus was significantly higher in the Duran ring group (P < .05). CONCLUSIONS: Significant pannus around the annuloplasty ring on CT may cause functional MS after mitral ring annuloplasty. This may occur more frequently with the Duran ring.

[Mitral valve interventions: Where do we stand?]. / Mitralklappeninterventionen : Wo stehen wir?

Mitral valve regurgitation (MR) with resulting heart failure is one of the most prevalent types of valvular heart disease. Currently, various approaches to catheter-based therapy of MR are already available for patients deemed to be at high-risk for surgery. Most experience has been gained with the MitraClip® system. Technological developments in the field of catheter-based treatment of MR is advancing at a rapid pace, with treatment modalities suited for patients with both primary and secondary MR. Annuloplasty is the surgical gold standard, particularly for patients with secondary MR. For catheter-based therapy of secondary MR a distinction is made between indirect and direct annuloplasty, with the latter most closely corresponding to surgical ring implantation. Catheter-based mitral valve replacement is technically feasible at present; however, experience is still limited and only few reports have been published. Technological development is markedly slower than in the field of transcatheter aortic valve replacement, predominantly owing to the far more complex structure of the mitral valve. Positive experience has already been gained with catheter-based implantation of prostheses designed for the aortic valve into degenerated mitral valve bioprostheses and failed surgical mitral annuloplasty rings (valve-in-valve and valve-in-ring implantation). Further approaches to catheter-based treatment of MR in high-risk surgical patients are expected in the future.

A quantitative approach to the intraoperative echocardiographic assessment of the mitral valve for repair.

Intraoperative echocardiography of the mitral valve has evolved from a qualitative assessment of flow-dependent variables to quantitative geometric analyses before and after repair. In addition, 3-dimensional echocardiographic data now allow for a precise assessment of mitral valve apparatus. Complex structures, such as the mitral annulus, can be interrogated comprehensively without geometric assumptions. Quantitative analyses of mitral valve apparatus are particularly valuable for identifying indices of left ventricular and mitral remodeling to establish the chronicity and severity of mitral regurgitation. This can help identify patients who may be unsuitable candidates for repair as the result of irreversible remodeling of the mitral valve apparatus. Principles of geometric analyses also have been extended to the assessment of repaired mitral valves. Changes in mitral annular shape and size determine the stress exerted on the mitral leaflets and, therefore, the durability of repair. Given this context, echocardiographers may be expected to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success and failure of the repair procedure. As a result, anesthesiologists have progressed from being mere service providers to participants in the decision-making process. It is therefore prudent for them to acquaint themselves with the principles of intraoperative quantitative mitral valve analysis to assist in rational and objective decision making.

Is robotic mitral valve surgery more expensive than its conventional counterpart?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Is robotic mitral valve surgery more expensive than its conventional counterpart?' Altogether 19 papers were found using the reported search, of which 5 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. There is a general impression in the surgical community that robotic operations might incur prohibitive additional costs. There is a paucity of data in the literature regarding cost analysis in cardiac robotic surgery. From the five studies, four were single institution experiences and one was a database inquiry study. These four studies showed that operational costs are higher for robotic cases but this was partially (one study) or completely (three studies) offset by lower postoperative costs. Overall hospital costs were similar between the two approaches in three studies and one study showed higher costs in the robotic group. Higher operating theatre (OT) costs were driven mainly by use of robotic instruments (approximately US$1500 per case) and longer OT times. Savings in postoperative care were driven by shorter length of hospital stay (on average 2 days fewer in robotic cases) and lower morbidity. If amortization cost, that is, the value of the initial capital investment on the robotic system divided by all operations performed, is included in this analysis, robotic approach becomes significantly more expensive by approximately US$3400 per case. The fifth study was a large national database inquiry in which robotic approach was found to be more expensive by US$600 per case excluding amortization cost and by US$3700 if amortization is included. We conclude that the total hospital cost of robotic mitral valve surgery is slightly higher than conventional sternotomy surgery. If amortization is taken into consideration, robotic cases are considerably more expensive.

Interventional treatment for structural heart disease: who is deciding, and can we afford it?

During the last years, the numbers of interventions in structural heart disease such as transcatheter aortic valve implantation (TAVI), percutaneous treatment of mitral regurgitation using the MitraClip, closure of atrial septal defects (ASD) and others have constantly increased. While the 20th century was called the century of surgery, it appears that the present century might be the century of minimally invasive percutaneous therapy. The reduced invasiveness of these procedures and the success in elderly patients make these treatments increasingly attractive for younger and healthier patients. Now that these procedures are moving forward, some questions arise, namely, who is deciding on treatment modality, and can we afford it?

Design considerations and quantitative assessment for the development of percutaneous mitral valve stent.

Percutaneous heart valve replacement is gaining popularity, as more positive reports of satisfactory early clinical experiences are published. However this technique is mostly used for the replacement of pulmonary and aortic valves and less often for the repair and replacement of atrioventricular valves mainly due to their anatomical complexity. While the challenges posed by the complexity of the mitral annulus anatomy cannot be mitigated, it is possible to design mitral stents that could offer good anchorage and support to the valve prosthesis. This paper describes four new Nitinol based mitral valve designs with specific features intended to address migration and paravalvular leaks associated with mitral valve designs. The paper also describes maximum possible crimpability assessment of these mitral stent designs using a crimpability index formulation based on the various stent design parameters. The actual crimpability of the designs was further evaluated using finite element analysis (FEA). Furthermore, fatigue modeling and analysis was also done on these designs. One of the models was then coated with polytetrafluoroethylene (PTFE) with leaflets sutured and put to: (i) leaflet functional tests to check for proper coaptation of the leaflet and regurgitation leakages on a phantom model and (ii) anchorage test where the stented valve was deployed in an explanted pig heart. Simulations results showed that all the stents designs could be crimped to 18F without mechanical failure. Leaflet functional test results showed that the valve leaflets in the fabricated stented valve coapted properly and the regurgitation leakage being within acceptable limits. Deployment of the stented valve in the explanted heart showed that it anchors well in the mitral annulus. Based on these promising results of the one design tested, the other stent models proposed here were also considered to be promising for percutaneous replacement of mitral valves for the treatment of mitral regurgitation, by virtue of their key features as well as effective crimping. These models will be fabricated and put to all the aforementioned tests before being taken for animal trials.

Biomechanical assessment of surgical repair of the mitral valve.

Repair of the mitral valve is defined (loosely) as a procedure that alters the valve structure, without replacement, enabling the natural valve itself to continue to perform under the physical conditions to which it is exposed. As the mitral valve is driven by flow and pressure, it should be feasible to analyse and assess its function, failure and repair as a mechanical system. This article reviews the current state of mechanical evaluation of surgical repairs of the failed mitral valve of the heart. This review describes the anatomy and physiology of the mitral valve, followed by the failure of the mitral valve from a mechanical point of view. The surgical methods used to repair failed valves are introduced, while the use of engineering analysis to aid understanding of mitral valve repair is also reviewed. Finally, a section on recommendations for development and future uses of engineering techniques to surgical repair are presented.