Relative importance of aneurysm diameter and body size for predicting abdominal aortic aneurysm rupture in men and women

OBJECTIVE

Women have been shown to have up to a fourfold higher risk of abdominal aortic aneurysm (AAA) rupture at any given aneurysm diameter compared with men, leading to recommendations to offer repair to women at lower diameter thresholds. Although this higher risk of rupture may simply reflect greater relative aortic dilatation in women who have smaller aortas to begin with, this has never been quantified. Our objective was therefore to quantify the relationship between rupture and aneurysm diameter relative to body size and determine whether a differential association between aneurysm diameter, body size, and rupture risk exists for men and women.

METHODS

We performed a retrospective review of all patients in the Vascular Study Group of New England (VSGNE) database who underwent endovascular or open AAA repair. Height and weight were used to calculate each patient's body mass index and body surface area (BSA). Next, indices of each measure of body size (height, weight, body mass index, BSA) relative to aneurysm diameter were calculated for each patient. To generate these indices, we divided aneurysm diameter (in cm) by the measure of body size; for example, aortic size index (ASI) = aneurysm diameter (cm)/BSA (m(2)). Along with other relevant clinical variables, we used these indices to construct different age-adjusted and multivariable-adjusted logistic regression models to determine predictors of ruptured repair vs elective repair. Models for men and women were developed separately, and different models were compared using the area under the curve.

RESULTS

We identified 4045 patients (78% male) who underwent AAA repair (53% endovascular aortic aneurysm repairs). Women had significantly smaller diameter aneurysms, lower BSA, and higher BSA indices than men. For men, the variable that increased the odds of rupture the most was aneurysm diameter (area under the curve = 0.82). Men exhibited an increased rupture risk with increasing aneurysm diameter (<5.5 cm: odds ratio [OR], 1.0; 5.5-6.4 cm: OR, 0.9; 95% confidence interval [CI], 0.5-1.7; P = .771; 6.5-7.4 cm: OR, 3.9; 95% CI, 1.9-1.0; P < .001; ≥ 7.5 cm: OR, 11.3; 95% CI, 4.9-25.8; P < .001). In contrast, the variable most predictive of rupture in women was ASI (area under the curve = 0.81), with higher odds of rupture at a higher ASI (ASI >3.5-3.9: OR, 6.4; 95% CI, 1.7-24.1; P = .006; ASI ≥ 4.0: OR, 9.5; 95% CI, 2.3-39.4; P = .002). For women, aneurysm diameter was not a significant predictor of rupture after adjusting for ASI.

CONCLUSIONS

Aneurysm diameter indexed to body size is the most important determinant of rupture for women, whereas aneurysm diameter alone is most predictive of rupture for men. Women with the largest diameter aneurysms and the smallest body sizes are at the greatest risk of rupture.

Handheld Point-of-Care Ultrasound Probes: The New Generation of POCUS

Recent advances in ultrasound technology have made ultrasound equipment more versatile, portable, and accessible than ever. Modern handheld, ultra-portable ultrasound devices have been developed by multiple companies and are contributing to make bedside ultrasound evaluation a practice available to all physicians. The significance of making point-of-care ultrasound (POCUS) a common practice that all physicians eventually can use in the evaluation of their patients is changing the way medicine is practiced, allowing physicians to quickly obtain valuable information to complement the traditional physical examination. Despite the proven benefits of using bedside ultrasound imaging as a part of the patient evaluation and for procedure guidance, adoption of this technology still is not widespread among anesthesiology clinicians nor is there uniform teaching of ultrasound skills to anesthesia residents and faculty. Among obstacles that have been identified as precluding achievement of the goal of widespread utilization of POCUS among anesthesia professionals and trainees, are the availability of equipment for all physicians when it is needed and lack of instructor supervision for trainees who desire to use ultrasound but do not always have an instructor knowledgeable in POCUS with them when an ultrasound examination is warranted. Herein, the characteristics, advantages, and limitations of available ultra-portable, handheld ultrasound devices are analyzed, with a focus on the Butterfly iQ (Butterfly Network, Inc, Guilford, CT) pocket probe, which is available at the authors’ institution, and how some of its features, such as the capacity to emulate multiple transducers and its cloud-sharing and teleguidance technology, may contribute to increase the availability and use of POCUS by anesthesia clinicians.

Presentation, treatment, and outcome differences between men and women undergoing revascularization or amputation for lower extremity peripheral arterial disease

OBJECTIVE

Prior studies have suggested treatment and outcome disparities between men and women for lower extremity peripheral arterial disease after surgical bypass. Given the recent shift toward endovascular therapy, which has increasingly been used to treat claudication, we sought to analyze sex disparities in presentation, revascularization, amputation, and inpatient mortality.

METHODS

We identified individuals with intermittent claudication and critical limb ischemia (CLI) using International Classification of Diseases, Ninth Revision codes in the Nationwide Inpatient Sample from 1998 to 2009. We compared presentation at time of intervention (intermittent claudication vs CLI), procedure (open surgery vs percutaneous transluminal angioplasty or stenting vs major amputation), and in-hospital mortality for men and women. Regional and ambulatory trends were evaluated by performing a separate analysis of the State Inpatient and Ambulatory Surgery Databases from four geographically diverse states: California, Florida, Maryland, and New Jersey.

RESULTS

From the Nationwide Inpatient Sample, we identified 1,797,885 patients (56% male) with intermittent claudication (26%) and CLI (74%), who underwent 1,865,999 procedures (41% open surgery, 20% percutaneous transluminal angioplasty or stenting, and 24% amputation). Women were older at the time of intervention by 3.5 years on average and more likely to present with CLI (75.9% vs 72.3%; odds ratio [OR], 1.21; 95% confidence interval [CI], 1.21-1.23; P < .01). Women were more likely to undergo endovascular procedures for both intermittent claudication (47% vs 41%; OR, 1.27; 95% CI, 1.25-1.28; P < .01) and CLI (21% vs 19%; OR, 1.14; 95% CI, 1.13-1.15; P < .01). From 1998 to 2009, major amputations declined from 18 to 11 per 100,000 in men and 16 to 7 per 100,000 in women, predating an increase in total CLI revascularization procedures that was seen starting in 2005 for both men and women. In-hospital mortality was higher in women regardless of disease severity or procedure performed even after adjusting for age and baseline comorbidities (.5% vs .2% after percutaneous transluminal angioplasty or stenting for intermittent claudication; 1.0% vs .7% after open surgery for intermittent claudication; 2.3% vs 1.6% after percutaneous transluminal angioplasty or stenting for CLI; 2.7% vs 2.2% after open surgery for CLI; P < .01 for all comparisons).

CONCLUSIONS

There appears to be a preference to perform endovascular over surgical revascularization among women, who are older and have more advanced disease at presentation. Percutaneous transluminal angioplasty or stenting continues to be popular and is increasingly being performed in the outpatient setting. Amputation and in-hospital mortality rates have been declining, and women now have lower amputation but higher mortality rates than men. Recent improvements in outcomes are likely the result of a combination of improved medical management and risk factor reduction.

Stretch-induced IL-8 depends on c-Jun NH2-terminal and nuclear factor-kappaB-inducing kinases

Positive pressure ventilation with large tidal volumes has been shown to cause release of cytokines, including interleukin (IL)-8. The mechanisms regulating lung stretch-induced cytokine production are unclear. We hypothesized that stretch-induced IL-8 production is dependent on the activation of the mitogen-activated protein kinases, c-Jun NH2-terminal kinases (JNK), p38, and/or extracellular signal-regulated kinase (ERK) 1/2. We exposed A549 cells, a type II-like alveolar epithelial cell line, to cyclic stretch at 20 cycles/min for 5 min-2 h. Cyclic stretch induced IL-8 protein production, IL-8 mRNA expression, and JNK activation, but only transient activation of p38 and ERK1/2. Inhibition of stretch-induced JNK activation by adenovirus-mediated gene transfer of stress-activated protein kinase (SEK-1), a dominant-negative mutant of SEK-1, the immediate upstream activator of the JNKs, and pharmacological JNK inhibitor II SP-600125 blocked IL-8 mRNA expression and attenuated IL-8 production. Inhibition of p38 and ERK1/2 did not affect stretch-induced IL-8 production. Stretch-induced activation NF-kappaB and activator protein (AP)-1 was blocked by NF-kappaB inhibitor and JNK inhibitor, respectively. An NF-IL-6 site was not essential for cyclic stretch-induced IL-8 promoter activity. Stretch also induced NF-kappaB-inducing kinase (NIK) activation, and inhibition of NF-kappaB attenuated IL-8 mRNA expression and IL-8 production. We conclude that stretch-induced transcriptional regulation of IL-8 mRNA and IL-8 production was via activation of AP-1 and NF-kappaB and was dependent on JNK and NIK activation, respectively.

Transesophageal echocardiography and noncardiac surgery

The use of transesophageal echocardiography (TEE) for monitoring during cardiac and noncardiac surgery has increased exponentially over the past few decades. TEE has evolved from a diagnostic tool to a monitoring device and a procedural adjunct. The close proximity of the TEE transducer to the heart generates high-quality images of the intracardiac structures and their spatial orientation. The use of TEE in noncardiac and critical care settings is not well studied, and the evidence of the benefits of its use in these settings is lacking. Despite the widespread availability of TEE equipment in US hospitals, less than 30% of anesthesiologists are formally trained in the use of perioperative TEE. In this review, the safety and indications of TEE are reviewed and detailed analysis of the best available evidence in this regard is presented. Landmark trials evaluating the use of TEE and its therapeutic impact in noncardiac surgical setting are critically reviewed. This article details recommendations to familiarize anesthesiologists with TEE technology to exploit it to its fullest potential to achieve better patient monitoring standards and eventually improve outcome. Training of greater numbers of anesthesiologists in TEE is needed to increase awareness of the indications and contraindications. Until relatively inexpensive TEE equipment is available, the initial cost of equipment acquisition remains a significant prohibitive factor limiting its widespread use.

Tricuspid annular geometry: a three-dimensional transesophageal echocardiographic study

OBJECTIVE

To demonstrate the clinical feasibility of accurately measuring tricuspid annular area by 3-dimensional (3D) transesophageal echocardiography (TEE) and to assess the geometric differences based on the presence of tricuspid regurgitation (TR). Also, the shape of the tricuspid annulus was compared with previous descriptions in the literature.

DESIGN

Prospective.

SETTING

Tertiary care university hospital.

INTERVENTIONS

Three-dimensional TEE.

PARTICIPANTS

Patients undergoing cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Volumetric data sets from 20 patients were acquired by 3D TEE and prospectively analyzed. Comparisons in annular geometry were made between groups based on the presence of TR. The QLab (Philips Medical Systems, Andover, MA) software package was used to calculate tricuspid annular area by both linear elliptical dimensions and planimetry. Further analyses were performed in the 4D Cardio-View (TomTec Corporation GmBH, Munich, Germany) and MATLAB (Natick, MA) software environments to accurately assess annular shape. It was found that patients with greater TR had an eccentrically dilated annulus with a larger annular area. Also, the area as measured by the linear ellipse method was overestimated as compared to the planimetry method. Furthermore, the irregular saddle-shaped geometry of the tricuspid annulus was confirmed through the mathematic model developed by the authors.

CONCLUSIONS

Three-dimensional TEE can be used to measure the tricuspid annular area in a clinically feasible fashion, with an eccentric dilation seen in patients with TR. The tricuspid annulus shape is complex, with annular high and low points, and annular area calculation based on linear measurements significantly overestimates 3D planimetered area.

Perioperative assessment of diastolic dysfunction

Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.

Dynamic 3-dimensional echocardiographic assessment of mitral annular geometry in patients with functional mitral regurgitation

BACKGROUND

Mitral valve (MV) annular dynamics have been well described in animal models of functional mitral regurgitation (FMR). Despite this, little if any data exist regarding the dynamic MV annular geometry in humans with FMR. In the current study we hypothesized that 3-dimensional (3D) echocardiography, in conjunction with commercially available software, could be used to quantify the dynamic changes in MV annular geometry associated with FMR.

METHODS

Intraoperative 3D transesophageal echocardiographic data obtained from 34 patients with FMR and 15 controls undergoing cardiac operations were dynamically analyzed for differences in mitral annular geometry with TomTec 4D MV Assessment 2.0 software (TomTec Imaging Systems GmbH, Munich, Germany).

RESULTS

In patients with FMR, the mean mitral annular area (14.6 cm(2) versus 9.6 cm(2)), circumference (14.1 cm versus 11.4 cm), anteroposterior (4.0 cm versus 3.0 cm) and anterolateral-posteromedial (4.3 cm versus 3.6 cm) diameters, tenting volume (6.2 mm(3) versus 3.5 mm(3)) and nonplanarity angle (NPA) (154 degrees ± 15 versus 136 degrees ± 11) were greater at all points during systole compared with controls (p < 0.01). Vertical mitral annular displacement (5.8 mm versus 8.3 mm) was reduced in FMR compared with controls (p < 0.01).

CONCLUSIONS

There are significant differences in dynamic mitral annular geometry between patients with FMR and those without. We were able to analyze these changes in a clinically feasible fashion. Ready availability of this information has the potential to aid comprehensive quantification of mitral annular function and possibly assist in both clinical decision making and annuloplasty ring selection.

Echocardiography derived three-dimensional printing of normal and abnormal mitral annuli

AIMS AND OBJECTIVES

The objective of this study was to assess the clinical feasibility of using echocardiographic data to generate three-dimensional models of normal and pathologic mitral valve annuli before and after repair procedures.

MATERIALS AND METHODS

High-resolution transesophageal echocardiographic data from five patients was analyzed to delineate and track the mitral annulus (MA) using Tom Tec Image-Arena software. Coordinates representing the annulus were imported into Solidworks software for constructing solid models. These solid models were converted to stereolithographic (STL) file format and three-dimensionally printed by a commercially available Maker Bot Replicator 2 three-dimensional printer. Total time from image acquisition to printing was approximately 30 min.

RESULTS

Models created were highly reflective of known geometry, shape and size of normal and pathologic mitral annuli. Post-repair models also closely resembled shapes of the rings they were implanted with. Compared to echocardiographic images of annuli seen on a computer screen, physical models were able to convey clinical information more comprehensively, making them helpful in appreciating pathology, as well as post-repair changes.

CONCLUSIONS

Three-dimensional printing of the MA is possible and clinically feasible using routinely obtained echocardiographic images. Given the short turn-around time and the lack of need for additional imaging, a technique we describe here has the potential for rapid integration into clinical practice to assist with surgical education, planning and decision-making.

Non-invasive transdermal two-dimensional mapping of cutaneous oxygenation with a rapid-drying liquid bandage

Oxygen plays an important role in wound healing, as it is essential to biological functions such as cell proliferation, immune responses and collagen synthesis. Poor oxygenation is directly associated with the development of chronic ischemic wounds, which affect more than 6 million people each year in the United States alone at an estimated cost of $25 billion. Knowledge of oxygenation status is also important in the management of burns and skin grafts, as well as in a wide range of skin conditions. Despite the importance of the clinical determination of tissue oxygenation, there is a lack of rapid, user-friendly and quantitative diagnostic tools that allow for non-disruptive, continuous monitoring of oxygen content across large areas of skin and wounds to guide care and therapeutic decisions. In this work, we describe a sensitive, colorimetric, oxygen-sensing paint-on bandage for two-dimensional mapping of tissue oxygenation in skin, burns, and skin grafts. By embedding both an oxygen-sensing porphyrin-dendrimer phosphor and a reference dye in a liquid bandage matrix, we have created a liquid bandage that can be painted onto the skin surface and dries into a thin film that adheres tightly to the skin or wound topology. When captured by a camera-based imaging device, the oxygen-dependent phosphorescence emission of the bandage can be used to quantify and map both the pO2 and oxygen consumption of the underlying tissue. In this proof-of-principle study, we first demonstrate our system on a rat ischemic limb model to show its capabilities in sensing tissue ischemia. It is then tested on both ex vivo and in vivo porcine burn models to monitor the progression of burn injuries. Lastly, the bandage is applied to an in vivo porcine graft model for monitoring the integration of full- and partial-thickness skin grafts.

Artificial intelligence in mitral valve analysis

Background:

Echocardiographic analysis of mitral valve (MV) has become essential for diagnosis and management of patients with MV disease. Currently, the various software used for MV analysis require manual input and are prone to interobserver variability in the measurements.

Aim:

The aim of this study is to determine the interobserver variability in an automated software that uses artificial intelligence for MV analysis.

Settings and Design:

Retrospective analysis of intraoperative three-dimensional transesophageal echocardiography data acquired from four patients with normal MV undergoing coronary artery bypass graft surgery in a tertiary hospital.

Materials and Methods:

Echocardiographic data were analyzed using the eSie Valve Software (Siemens Healthcare, Mountain View, CA, USA). Three examiners analyzed three end-systolic (ES) frames from each of the four patients. A total of 36 ES frames were analyzed and included in the study.

Statistical Analysis:

A multiple mixed-effects ANOVA model was constructed to determine if the examiner, the patient, and the loop had a significant effect on the average value of each parameter. A Bonferroni correction was used to correct for multiple comparisons, and P = 0.0083 was considered to be significant.

Results:

Examiners did not have an effect on any of the six parameters tested. Patient and loop had an effect on the average parameter value for each of the six parameters as expected (P < 0.0083 for both).

Conclusion:

We were able to conclude that using automated analysis, it is possible to obtain results with good reproducibility, which only requires minimal user intervention.

Effects of neuropeptide Y on collateral development in a swine model of chronic myocardial ischemia

We investigated the role of neuropeptide Y (NPY), abundant in the myocardial sympathetic nervous system and endothelial cells, in angiogenesis during chronic myocardial ischemia. Adult male Yorkshire swine underwent ameroid constrictor placement on the proximal left circumflex coronary artery. After 3 weeks, an osmotic pump was placed to deliver either placebo (control, n=8) or NPY(3-36) (NPY, n=8) to the collateral dependent region. Five weeks after pump placement, after cardiac catheterization and hemodynamic assessment, the heart was harvested for analysis. NPY treated animals demonstrated increased mean arterial pressures and improved left ventricular function (+dP/dt). Cardiac catheterization demonstrated a significant increase in the blush score in the NPY group (p<0.001). Blood flow to the ischemic myocardium was not different between groups at rest or during ventricular pacing. Immunohistochemical double staining for CD-31 and smooth muscle actin demonstrated an increase in capillary and arteriole formation in NPY treated animals (p=0.02 and p<0.001). Immunoblotting showed a significant upregulation of DPPIV (p=0.009) and NPY receptors 1 (p=0.008), 2 (p=0.02) and 5 (p=0.03) in the NPY treated group. Additionally, there was significant upregulation of VEGF (p=0.04), eNOS (p=0.014), phospho-eNOS (ser1177) (p=0.02), and PDGF (p<0.001) in NPY treated group. The anti-angiogenic factors endostatin and angiostatin were significantly decreased in NPY treated animals (endostatin, p=0.03; angiostatin, p=0.04). Exogenous NPY(3-36) resulted in improved myocardial function and increased angiogenesis and arteriogenesis by stimulating growth factor, pro-angiogenic receptor upregulation, and decreasing anti-angiogenic expression, but did not increase blood flow to the ischemic myocardium. NPY may act as a good adjunct to primary agents of therapeutic angiogenesis.

Mitochondrial Dysfunction in Atrial Tissue of Patients Developing Postoperative Atrial Fibrillation

BACKGROUND

Mitochondria are the major site of cellular oxidation. Metabolism and oxidative stress have been implicated as possible mechanisms for postoperative atrial fibrillation (POAF) after cardiac operations. Establishing the precise nature of mitochondrial dysfunction as an etiologic factor for oxidative stress-related cell death and apoptosis could further the understanding of POAF. To establish this relationship, mitochondrial function was studied in patients undergoing cardiac operations that developed POAF and compared it with patients without POAF.

METHODS

Right atrial tissue and serum samples were collected from 85 patients before and after cardiopulmonary bypass. Microarray analysis (36 patients) and RNA sequencing (5 patients) were performed on serum and atrial tissues, respectively, for identifying significantly altered genes in patients who developed POAF. On the basis of these results, Western blot was performed in 52 patients for the genes that were most altered, and functional pathways were established.

RESULTS

POAF developed in 30.6% (n = 26) of patients. Serum microarray showed significant fold changes in the expression of 49 genes involved in inflammatory response, oxidative stress, apoptosis, and amyloidosis (p < 0.05) in the POAF group. Similarly, RNA sequencing demonstrated an increased expression of genes associated with inflammatory response, fatty acid metabolism, and apoptosis in the POAF group (false discovery rate > 0.05). Immunoblotting showed a significant increase in TNFAIP6 (tumor necrosis factor, α-induced protein 6; p = 0.02) and transforming growth factor-β (p = 0.04) after cardiopulmonary bypass in the POAF group. There was a significant decrease in PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α; p = 0.002) and CPT1 (carnitine palmitoyltransferase I; p < 0.0005) in the POAF group after cardiopulmonary bypass.

CONCLUSIONS

Compared with patients without POAF, those with POAF demonstrated mitochondrial dysfunction at various levels that are suitable for potential pharmacotherapy.

Neuropeptide Y is an angiogenic factor in cardiovascular regeneration

In diabetic cardiomyopathy, there is altered angiogenic signaling and increased oxidative stress. As a result, anti-angiogenic and pro-inflammatory pathways are activated. These disrupt cellular metabolism and cause fibrosis and apoptosis, leading to pathological remodeling. The autonomic nervous system and neurotransmitters play an important role in angiogenesis. Therapies that promote angiogenesis may be able to relieve the pathology in these disease states. Neuropeptide Y (NPY) is the most abundantly produced and expressed neuropeptide in the central and peripheral nervous systems in mammals and plays an important role in promoting angiogenesis and cardiomyocyte remodeling. It produces effects through G-protein-coupled Y receptors that are widely distributed and also present on the myocardium. Some of these receptors are also involved in diseased states of the heart. NPY has been implicated as a potent growth factor, causing cell proliferation in multiple systems while the NPY3-36 fragment is selective in stimulating angiogenesis and cardiomyocyte remodeling. Current research is focusing on developing a drug delivery mechanism for NPY to prolong therapy without having significant systemic consequences. This could be a promising innovation in the treatment of diabetic cardiomyopathy and ischemic heart disease.

Tricuspid annulus: a three-dimensional deconstruction and reconstruction

BACKGROUND

Before clinical manifestation of regurgitation, the tricuspid annulus dilates and flattens when right ventricular dysfunction is potentially reversible. That makes the case for a prophylactic tricuspid annuloplasty even in the absence of significant tricuspid regurgitation. Owing to the appreciation of the favorable prognostic value of tricuspid annuloplasty, the geometry of the normal tricuspid annulus merits critical analysis.

METHODS

Three-dimensional transesophageal echocardiographic data from 26 patients were analyzed using Image Arena (TomTec, Munich, Germany) software. Cartesian coordinate data from tricuspid annuli were exported to MATLAB (Mathworks, Natick, MA) for further processing. Annular metrics related to size, shape, and motion were computed.

RESULTS

The tricuspid annulus demonstrated significant changes in area (p<0.01) and perimeter (p<0.03) during the cardiac cycle, with maximum values attained at end diastole. There was significant correlation between two- and three-dimensional area changes, indicating true expansion in the annulus. The anterolateral region of the annulus demonstrated the greatest dynamism (p<0.01), and the anteroseptal region showed the least. The anteroseptal region also displayed the most nonplanarity in the annulus. In addition, vertical translational motion was observed, with a mean distance of 11.3±3.7 mm between end systolic and end diastolic annular centroids.

CONCLUSIONS

The tricuspid annulus is a dynamic, multiplanar structure with heterogeneous regional behavior. These characteristics should be taken into account for optimal annuloplasty device design and efficacy.