Strain estimation in aortic roots from 4D echocardiographic images using medial modeling and deformable registration

Even though the central role of mechanics in the cardiovascular system is widely recognized, estimating mechanical deformation and strains in-vivo remains an ongoing practical challenge. Herein, we present a semi-automated framework to estimate strains from four-dimensional (4D) echocardiographic images and apply it to the aortic roots of patients with normal trileaflet aortic valves (TAV) and congenital bicuspid aortic valves (BAV). The method is based on fully nonlinear shell-based kinematics, which divides the strains into in-plane (shear and dilatational) and out-of-plane components. The results indicate that, even for size-matched non-aneurysmal aortic roots, BAV patients experience larger regional shear strains in their aortic roots. This elevated strains might be a contributing factor to the higher risk of aneurysm development in BAV patients. The proposed framework is openly available and applicable to any tubular structures.

Dynamic Volumetric Assessment of the Aortic Root: The Influence of Bicuspid Aortic Valve Competence

BACKGROUND

Aortic root evaluation is conventionally based on 2-dimensional measurements at a single phase of the cardiac cycle. This work presents an image analysis method for assessing dynamic 3-dimensional changes in the aortic root of minimally calcified bicuspid aortic valves (BAVs) with and without moderate to severe aortic regurgitation.

METHODS

The aortic root was segmented over the full cardiac cycle in 3-dimensional transesophageal echocardiographic images acquired from 19 patients with minimally calcified BAVs and from 16 patients with physiologically normal tricuspid aortic valves (TAVs). The size and dynamics of the aortic root were assessed using the following image-derived measurements: absolute mean root volume and mean area at the level of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction, as well as normalized root volume change and normalized area change of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction over the cardiac cycle.

RESULTS

Normalized volume change over the cardiac cycle was significantly greater in BAV roots with moderate to severe regurgitation than in normal TAV roots and in BAV roots with no or mild regurgitation. Aortic root dynamics were most significantly different at the mid-level of the sinuses of Valsalva in BAVs with moderate to severe regurgitation than in competent TAVs and BAVs.

CONCLUSIONS

Echocardiographic reconstruction of the aortic root demonstrates significant differences in dynamics of BAV roots with moderate to severe regurgitation relative to physiologically normal TAVs and competent BAVs. This finding may have implications for risk of future dilatation, dissection, or rupture, which warrant further investigation.

Relationships between resilience and quality of life in parents of children with cancer

CLINICALTRIALS.GOV ID

NCT03631485.

In Vivo Image-Based 4D Modeling of Competent and Regurgitant Mitral Valve Dynamics

BACKGROUND

In vivo characterization of mitral valve dynamics relies on image analysis algorithms that accurately reconstruct valve morphology and motion from clinical images. The goal of such algorithms is to provide patient-specific descriptions of both competent and regurgitant mitral valves, which can be used as input to biomechanical analyses and provide insights into the pathophysiology of diseases like ischemic mitral regurgitation (IMR).

OBJECTIVE

The goal is to generate accurate image-based representations of valve dynamics that visually and quantitatively capture normal and pathological valve function.

METHODS

We present a novel framework for 4D segmentation and geometric modeling of the mitral valve in real-time 3D echocardiography (rt-3DE), an imaging modality used for pre-operative surgical planning of mitral interventions. The framework integrates groupwise multi-atlas label fusion and template-based medial modeling with Kalman filtering to generate quantitatively descriptive and temporally consistent models of valve dynamics.

RESULTS

The algorithm is evaluated on rt-3DE data series from 28 patients: 14 with normal mitral valve morphology and 14 with severe IMR. In these 28 data series that total 613 individual 3DE images, each 3D mitral valve segmentation is validated against manual tracing, and temporal consistency between segmentations is demonstrated.

CONCLUSIONS

Automated 4D image analysis allows for reliable non-invasive modeling of the mitral valve over the cardiac cycle for comparison of annular and leaflet dynamics in pathological and normal mitral valves. Future studies can apply this algorithm to cardiovascular mechanics applications, including patient-specific strain estimation, fluid dynamics simulation, inverse finite element analysis, and risk stratification for surgical treatment.

The Penn Classification Predicts Hospital Mortality in Acute Stanford Type A and Type B Aortic Dissections

OBJECTIVES

Mortality in acute aortic dissection varies depending on anatomic location, extent, and associated complications. The Stanford classification guides surgical versus medical management. The Penn classification stratifies mortality risk in patients with Stanford type A aortic dissections undergoing surgery. The objective of the present study was to determine whether the Penn classification can predict hospital mortality in patients with acute Stanford type A and type B aortic dissections undergoing surgical or medical management.

DESIGN

Retrospective, observational study.

SETTING

Tertiary care, university hospital.

PARTICIPANTS

Patients with acute aortic dissection between January 2008 and December 2017.

INTERVENTIONS

Examination of hospital mortality after surgical or medical management.

MEASUREMENTS AND MAIN RESULTS

Three hundred fifty-two patients had confirmed dissections (186 type A, 166 type B). The overall mortality was 18.8% for type A and 13.3% for type B. Penn class A patients with type A or type B dissections undergoing surgical repair had the lowest mortality (both 3.1%). Penn class B, C, or B+C patients with type A dissections and Penn class B+C patients with type B dissections undergoing medical management had the greatest incidence of mortality (50.0%-57.1%). All others had intermediate mortality (6.7%-39.3%). Logistic regression analysis demonstrated that Penn class B, C, and B+C patients had a greater odds of mortality and predicted mortality than did Penn class A patients.

CONCLUSIONS

The Penn classification predicts hospital mortality in patients with acute Stanford type A or type B aortic dissections undergoing surgical or medical management. Early endovascular repair may confer lower risk of mortality in patients with type B dissections presenting without ischemia.

Relationships among hope, psychological well-being and health-related quality of life in childhood cancer survivors

This cross-sectional study examined the level of hope among Hong Kong childhood cancer survivors and investigated the relationships among hope, depressive symptoms, self-esteem and health-related quality of life. We recruited 176 survivors aged 10-16 years who underwent medical follow-ups at the outpatient clinic. This study revealed that lower levels of hope were associated with an increase in depressive symptoms and reductions in self-esteem and health-related quality of life. Our results contribute to novel findings by demonstrating that hope may be a significant factor associated with health-related quality of life. This understanding could increase healthcare professionals' awareness about the psychological needs of childhood cancer survivors.

The "Ice Age" in Cardiac Surgery: Evolution of the "Siberian" Method of Brain Protection During Deep Hypothermic Perfusionless Circulatory Arrest

Deep hypothermic perfusionless circulatory arrest was the first practical neuroprotective technique used for open-heart surgery. It was refined at the Novosibirsk Medical Research Center in Siberia and was actively used from the mid-1950s until 2001.This review describes the development of this technique and its contribution to our understanding of the dynamic changes in human physiology during induced hypothermia for circulatory arrest without extracorporeal perfusion. Deep hypothermic perfusionless circulatory arrest was an important stepping stone in the development of modern approaches in neuroprotection and monitoring during cardiac surgery.

Relationships among resilience, self-esteem, and depressive symptoms in Chinese adolescents

This study explored the relationships among resilience, self-esteem, and depressive symptoms in Hong Kong Chinese adolescents. We selected a stratified random sample of 1816 Form 1 students from all 18 districts of Hong Kong. This study revealed that about 21 percent adolescents are experiencing some depressive symptoms. Our results contribute novel findings to the literature showing that resilience is a strong indicator of adolescents at a higher risk of depression and increasing adolescents' resilience to psychological distress is crucial to enhance their mental well-being. It is crucial to develop interventions that can enhance resilience and promote positive mental well-being among adolescents.

Assessment of Left Ventricular Dimensions by Transoesophageal Echocardiography in Patients During Coronary Artery Bypass Surgery

OBJECTIVE

Normative values of left ventricular (LV) end-diastolic area and diameter (EDA and EDD) for intraoperative transoesophageal echocardiography (TEE) have not been established. We aimed to define the ranges of LV EDA and EDD for intraoperative TEE examinations in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

A MEDLINE search for studies reporting LV EDA and EDD in CABG patients was performed. Individual-level dataset from 333 anaesthetised and mechanically ventilated patients with preserved LV function (study population) were received from 8 studies. EDA and calculated EDD values in the study population were compared with summary mean EDD values obtained by transthoracic echocardiography (TTE) in 2 studies of 500 awake patients with coronary artery disease (CAD). Further, the influence of prespecified factors on EDD was evaluated through a multivariate regression model.

RESULTS

LV EDA and EDD values measured by TEE in anaesthetised CABG patients were 16.7±4.7 cm2 and 4.6±0.6 cm, respectively. EDD values measured by TEE in anaesthetised patients were 10% to 13% less those measured by TTE in 2 studies of awake patients (p<0.001). Body surface area, age and fractional area change but not sex were factors that affected LV EDD.

CONCLUSION

LV EDD values measured by intraoperative TEE in anaesthetised and mechanically ventilated CABG patients were 10% to 13% less than those measured by TTE in awake CAD patients. This finding indicates that independent normative values specific for intraoperative TEE should be established for guiding intraoperative clinical decisions.

Sodium bicarbonate use and the risk of hypernatremia in thoracic aortic surgical patients with metabolic acidosis following deep hypothermic circulatory arrest

Objective:

Metabolic acidosis after deep hypothermic circulatory arrest (DHCA) for thoracic aortic operations is commonly managed with sodium bicarbonate (NaHCO₃). The purpose of this study was to determine the relationships between total NaHCO₃ dose and the severity of metabolic acidosis, duration of mechanical ventilation, duration of vasoactive infusions, and Intensive Care Unit (ICU) or hospital length of stay (LOS).

Methods:

In a single center, retrospective study, 87 consecutive elective thoracic aortic operations utilizing DHCA, were studied. Linear regression analysis was used to test for the relationships between the total NaHCO₃ dose administered through postoperative day 2, clinical variables, arterial blood gas values, and short-term clinical outcomes.

Results:

Seventy-five patients (86%) received NaHCO₃. Total NaHCO₃ dose averaged 136 ± 112 mEq (range: 0.0–535 mEq) per patient. Total NaHCO₃ dose correlated with minimum pH (r = 0.41, P < 0.0001), minimum serum bicarbonate (r = −0.40, P < 0.001), maximum serum lactate (r = 0.46, P = 0.007), duration of metabolic acidosis (r = 0.33, P = 0.002), and maximum serum sodium concentrations (r = 0.29, P = 0.007). Postoperative hypernatremia was present in 67% of patients and peaked at 12 h following DHCA. Eight percent of patients had a serum sodium ≥ 150 mEq/L. Total NaHCO₃ dose did not correlate with anion gap, serum chloride, not the duration of mechanical ventilator support, vasoactive infusions, ICU or hospital LOS.

Conclusion:

Routine administration of NaHCO₃ was common for the management of metabolic acidosis after DHCA. Total dose of NaHCO₃ was a function of the severity and duration of metabolic acidosis. NaHCO₃ administration contributed to postoperative hypernatremia that was often severe. The total NaHCO₃ dose administered was unrelated to short-term clinical outcomes.

Techniques for Preserving Vertebral Artery Perfusion During Thoracic Aortic Stent Grafting Requiring Aortic Arch Landing

Thoracic endografting offers many advantages over open repair. However, delivery of the device can be difficult and may necessitate adjunctive procedures. We describe our techniques for preserving perfusion to the left subclavian artery despite endograft coverage to obtain a proximal seal zone. We reviewed our experience with the Talent thoracic stent graft (Medtronic, Santa Rosa, CA). From 1999 to 2003, 49 patients received this device (29 men, 20 women). Seventeen patients required adjunctive procedures to facilitate proximal graft placement. We performed left subclavian-to-left common carotid artery transposition (6), left common carotid-to-left subclavian artery bypass with ligation proximal to the vertebral artery (7), and left common carotid-to-left subclavian artery bypass with proximal coil embolization (4). Patients who had anatomy unfavorable to transposition or bypass with proximal ligation (large aneurysms or proximal vertebral artery origin) were treated with coil embolization of the proximal left subclavian artery in order to prevent subsequent type II endoleaks. Technical success rate of the carotid subclavian bypass was 100%. Patient follow-up ranged from 3 to 48 months with a mean of 12 months. Six patients had follow-up <6 months owing to recent graft placement. Primary patency was 100%. No neurologic events occurred during the procedure or upon follow-up. One patient had a transient chyle leak that spontaneously resolved in 24 hours. Another patient had a phrenic nerve paresis that resolved after 3 weeks. We believe that it is important to maintain patency of the vertebral artery specifically when a patent right vertebral system and an intact basilar artery is not demonstrated. Furthermore, we describe a novel technique of coil embolization of the proximal left subclavian artery in conjunction with left common carotid-to-left subclavian artery bypass. This circumvents the need for potentially hazardous mediastinal dissection and ligation of the proximal left subclavian artery in cases of large proximal aneurysms or unfavorable vertebral artery anatomy.

Protocol for prevention of spinal cord ischemia after thoracoabdominal aortic surgery

Objective

This manuscript was written to present a systemic protocol for the prevention, early detection, and treatment of spinal cord ischemia following open and endovascular thoracoabdominal aortic operations.

Methods

This protocol was a collaborative effort between surgeons, anesthesiologists and intensivists. It was implemented at our institution in November 2007. Nurses are trained to prevent, rapidly detect and ultimately aid in the treatment of spinal cord ischemia.

Results

Implementation of this protocol has aided in prevention, detection and treatment of spinal cord ischemia in patients after open and endovascular thoracoabdominal aortic operations.

Conclusion

Standardized care and reliance on trained nursing staff to monitor for symptoms following thoracoabdominal aortic operations are safe and aid in the rapid detection, treatment and reversal of spinal cord ischemia.

The value of preoperative 3-dimensional over 2-dimensional valve analysis in predicting recurrent ischemic mitral regurgitation after mitral annuloplasty

OBJECTIVES

Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.

METHODS

Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation. Two-dimensional echocardiography annular diameter and tethering parameters were measured in the apical 2- and 4-chamber views. A customized protocol was used to assess 3-dimensional annular geometry and regional leaflet tethering. Recurrence (grade ≥2) was assessed with 2-dimensional transthoracic echocardiography at 6 months.

RESULTS

Preoperative 2- and 3-dimensional annular geometry were similar in all patients with ischemic mitral regurgitation. Preoperative 2- and 3-dimensional leaflet tethering were significantly higher in patients with recurrence (n = 13) when compared with patients without recurrence (n = 37). Multivariate logistic regression revealed preoperative 2-dimensional echocardiography posterior tethering angle as an independent predictor of recurrence with an optimal cutoff value of 32.0° (area under the curve, 0.81; 95% confidence interval, 0.68-0.95; P = .002) and preoperative 3-dimensional echocardiography P3 tethering angle as an independent predictor of recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84-1.00; P < .001). The predictive value of the 3-dimensional geometric multivariate model can be augmented by adding basal aneurysm/dyskinesis (area under the curve, 0.94; 95% confidence interval, 0.87-1.00; P < .001).

CONCLUSIONS

Preoperative 3-dimensional echocardiography P3 tethering angle is a stronger predictor of ischemic mitral regurgitation recurrence after annuloplasty than preoperative 2-dimensional echocardiography posterior tethering angle, which is highly influenced by viewing plane. In patients with a preoperative P3 tethering angle of 29.9° or larger (especially when combined with basal aneurysm/dyskinesis), chordal-sparing valve replacement should be strongly considered.

Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty

BACKGROUND

Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if prerepair three-dimensional (3D) echocardiography combined with a novel valve-modeling algorithm would be predictive of IMR recurrence 6 months after repair.

METHODS

Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR and in 21 patients with normal mitral valves. A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair.

RESULTS

Preoperative annular geometry was similar in all IMR patients, and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) than in patients in whom IMR did not recur (n=37) (tethering index: 3.91 ± 1.01 vs 2.90 ± 1.17, p = 0.008; tethering angles of A3: 23.5° ± 8.9° vs 14.4° ± 11.4°, p = 0.012; P2: 44.4° ± 8.8° vs 28.2° ± 17.0°, p = 0.002; and P3: 35.2° ± 6.0° vs. 18.6° ± 12.7°, p < 0.001). Multivariate logistic regression analysis revealed the preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84 to 1.00; p < 0.001).

CONCLUSIONS

3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle of 29.9° or larger, chordal-sparing valve replacement rather than valve repair should be strongly considered.

Medially constrained deformable modeling for segmentation of branching medial structures: Application to aortic valve segmentation and morphometry

Deformable modeling with medial axis representation is a useful means of segmenting and parametrically describing the shape of anatomical structures in medical images. Continuous medial representation (cm-rep) is a "skeleton-first" approach to deformable medial modeling that explicitly parameterizes an object's medial axis and derives the object's boundary algorithmically. Although cm-rep has effectively been used to segment and model a number of anatomical structures with non-branching medial topologies, the framework is challenging to apply to objects with branching medial geometries since branch curves in the medial axis are difficult to parameterize. In this work, we demonstrate the first clinical application of a new "boundary-first" deformable medial modeling paradigm, wherein an object's boundary is explicitly described and constraints are imposed on boundary geometry to preserve the branching configuration of the medial axis during model deformation. This "boundary-first" framework is leveraged to segment and morphologically analyze the aortic valve apparatus in 3D echocardiographic images. Relative to manual tracing, segmentation with deformable medial modeling achieves a mean boundary error of 0.41 ± 0.10 mm (approximately one voxel) in 22 3DE images of normal aortic valves at systole. Deformable medial modeling is additionally demonstrated on pathological cases, including aortic stenosis, Marfan syndrome, and bicuspid aortic valve disease. This study demonstrates a promising approach for quantitative 3DE analysis of aortic valve morphology.

Segmentation of the Aortic Valve Apparatus in 3D Echocardiographic Images: Deformable Modeling of a Branching Medial Structure

3D echocardiographic (3DE) imaging is a useful tool for assessing the complex geometry of the aortic valve apparatus. Segmentation of this structure in 3DE images is a challenging task that benefits from shape-guided deformable modeling methods, which enable inter-subject statistical shape comparison. Prior work demonstrates the efficacy of using continuous medial representation (cm-rep) as a shape descriptor for valve leaflets. However, its application to the entire aortic valve apparatus is limited since the structure has a branching medial geometry that cannot be explicitly parameterized in the original cm-rep framework. In this work, we show that the aortic valve apparatus can be accurately segmented using a new branching medial modeling paradigm. The segmentation method achieves a mean boundary displacement of 0.6 ± 0.1 mm (approximately one voxel) relative to manual segmentation on 11 3DE images of normal open aortic valves. This study demonstrates a promising approach for quantitative 3DE analysis of aortic valve morphology.

Reversible spinal cord ischemia as a complication of acute aortic intramural hematoma

Aortic intramural hematoma is a variant of acute aortic dissection characterized by localized hemorrhage into the aortic media causing a separation of the intimal and adventitial layers of the aorta. Malperfusion represents an unusual presenting sign of acute intramural hematoma. Herein, we describe the case of a patient with an acute Type A IMH who developed reversible ischemic spinal cord syndrome after presenting with paraplegia as a consequence of malperfusion. A decision was made to delay operative repair and, instead, emergently apply medical interventions to increase spinal cord perfusion pressure. Medical treatment was effective for the treatment of spinal cord ischemia and operative repair of the intramural hematoma was accomplished after complete recovery of neurologic function. This is the third case ever reported of an intramural hematoma presenting in the form of spinal cord ischemia.

Feasibility of in vivo human aortic valve modeling using real-time three-dimensional echocardiography

BACKGROUND

Surgical techniques for aortic valve (AV) repair are directed toward restoring normal structural relationships in the aortic root and rely on detailed assessment of root and valve anatomy. Noninvasive three-dimensional (3D) imaging and modeling may assist in patient selection and operative planning.

METHODS

Transesophageal real-time 3D echocardiographic images of 5 patients with normal AVs were acquired. The aortic root and the annulus were manually segmented at end diastole using a 36-point rotational template. The AV leaflets and the coaptation zone were manually segmented in parallel 1-mm cross sections. Quantitative 3D models of the AV and root were generated and used to measure standard anatomic parameters and were compared to conventional two-dimensional echocardiographic measurements. All measurements are given as mean±SD.

RESULTS

Annular, sinus, and sinotubular junction areas were 4.1±0.6 cm2, 7.5±1.2 cm2, and 3.9±1.0 cm2, respectively. Root diameters (measured in three locations) by 3D model inspection and two-dimensional echocardiography measurement correlated (R2=0.75). Noncoapted areas of the left, right, and noncoronary leaflets were 1.9±0.2 cm2, 1.6±0.3 cm2, and 1.6±0.3 cm2, respectively. Mean coaptation areas for the left-right, left-noncoronary, and right-noncoronary coaptation zones were 87.7±36.9 mm2, 69.9±20.7 mm2, and 114.2±23.0 mm2, respectively. The mean ratio of noncoapted leaflet area to annular area was 1.3±0.2.

CONCLUSIONS

High-resolution 3D models of the in vivo normal human aortic root and valve were generated using 3D echocardiography. Quantitative 3D models and analysis may assist in characterization of pathology and decision making for AV repair.

Regional annular geometry in patients with mitral regurgitation: implications for annuloplasty ring selection

BACKGROUND

The saddle shape of the normal mitral annulus has been quantitatively described by several groups. There is strong evidence that this shape is important to valve function. A more complete understanding of regional annular geometry in diseased valves may provide a more educated approach to annuloplasty ring selection and design. We hypothesized that mitral annular shape is markedly distorted in patients with diseased valves.

METHODS

Real-time 3-dimensional echocardiography was performed in 20 patients with normal mitral valves, 10 with ischemic mitral regurgitation, and 20 with myxomatous mitral regurgitation (MMR). Thirty-six annular points were defined to generate a 3-dimensional model of the annulus. Regional annular parameters were measured from these renderings. Left ventricular inner diameter was obtained from 2-dimensional echocardiographic images.

RESULTS

Annular geometry was significantly different among the three groups. The annuli were larger in the MMR and in the ischemic mitral regurgitation groups. The annular enlargement was greater and more pervasive in the MMR group. Both diseases were associated with annular flattening, although though the regional distribution of that flattening was different between groups. Left ventricular inner diameter was increased in both groups. However, relative to the Left ventricular inner diameter, the annulus was disproportionately dilated in the MMR group.

CONCLUSIONS

Patients with MMR and ischemic mitral regurgitation have enlarged and flattened annuli. In the case of MMR, annular distortions may be the driving factor leading to valve incompetence. These data suggest that the goal of annuloplasty should be the restoration of normal annular saddle shape and that the use of flexible, partial, and flat rings may be ill advised.

The effect of surgical and transcatheter aortic valve replacement on mitral annular anatomy

BACKGROUND

The effect of aortic valve replacement on three-dimensional mitral annular geometry has not been well described. Emerging transcatheter approaches for aortic valve replacement employ fundamentally different mechanical techniques for achieving fixation and seal of the prosthetic valve than standard surgical aortic valve replacement. This study compares the immediate impact of transcatheter aortic valve replacement (TAVR) and standard surgical aortic valve replacement (AVR) on mitral annular anatomy.

METHODS

Real-time three-dimensional echocardiography was performed in patients undergoing TAVR using the Edwards Sapien valve (n = 10 [Edwards Lifesciences, Irvine, CA]) or AVR (n = 10) for severe aortic stenosis. Mitral annular geometric indexes were measured using Tomtec EchoView (Tomtec Imaging Systems, Munich, Germany) to assess regional and global annular geometry.

RESULTS

Mixed between-within analysis of variance showed no differences between TAVR and AVR groups in any of the mitral annular geometric indices preoperatively. However, postoperative analysis did demonstrate an effect of AVR on geometry. Patients undergoing open AVR had significant decrease in annular height, septolateral diameter, mitral valve transverse diameter, and mitral annular area after valve replacement (p ≤ 0.006). Similar changes were not noted in the TAVR group.

CONCLUSIONS

Mitral annular geometry is better preserved by TAVR than by AVR. Thus, TAVR may be a more physiologic approach to aortic replacement.

Neurological complications of thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.

Saddle-shape annuloplasty increases mitral leaflet coaptation after repair for flail posterior leaflet

BACKGROUND

The primary goal of surgical mitral repair is the reestablishment of normal leaflet coaptation. Surgical techniques that maintain or restore leaflet geometry promote leaflet coaptation. Recent 3-dimensional (3D) echocardiographic studies have shown that saddle-shaped annuloplasty has a salutary influence on leaflet geometry. Therefore we hypothesized that saddle-shaped annuloplasty would improve leaflet coaptation in cases of repair for flail posterior leaflet segments.

METHODS

Sixteen patients with flail posterior segment and severe mitral regurgitation had valve repair using standard techniques. Eight patients received saddle-shaped annuloplasty and 8 patients received flat annuloplasty. Real-time 3D transesophageal echocardiography was performed before and after repair. Images were analyzed using custom software to calculate mitral annular area (MAA), septolateral dimension (SLD), intercommissural width (CW), total leaflet area (TLA), and leaflet coaptation area (LCA).

RESULTS

Postrepair MAA (flat, 588.6±26.5 mm2; saddle, 628.0±35.3 mm2; p=0.12) and TLA (flat, 2198.5±151.6 mm2; saddle, 2303.9±183.8 mm2; p=0.67) were similar in both groups. Postrepair LCA was significantly greater in the saddle group than in the flat group (226.8±24.0 mm2 and 154.0±13.0 mm2, respectively; p=0.02).

CONCLUSIONS

Real-time 3D echocardiography and novel imaging software provide a powerful tool for analyzing mitral leaflet coaptation. When compared with flat annuloplasty, saddle-shaped annuloplasty improves LCA after mitral valve repair for severe mitral regurgitation secondary to flail posterior leaflet segment. Use of saddle-shaped annuloplasty devices may increase repair durability.

Risk factors, outcomes, and clinical manifestations of spinal cord ischemia following thoracic endovascular aortic repair

OBJECTIVE

The purpose of this study was to assess the incidence, risk factors, and clinical manifestations of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR).

METHODS

A retrospective review of a prospectively collected database was performed for all patients undergoing TEVAR at a single academic institution between July 2002 and June 2010. Preoperative demographics, procedure-related variables, and clinical details related to SCI were examined. Logistic regression analysis was performed to identify risk factors for the development of SCI.

RESULTS

Of the 424 patients who underwent TEVAR during the study period, 12 patients (2.8%) developed SCI. Mean age of this cohort with SCI was 69.6 years (range, 44-84 years), and 7 were women. One-half of these patients had prior open or endovascular aortic repair. Indication for surgery was either degenerative aneurysm (n = 8) or dissection (n = 4). Six TEVARs were performed electively, with the remaining done either urgently or emergently due to contained rupture (n = 2), dissection with malperfusion (n = 2), or severe back pain (n = 2). All 12 patients underwent extent C endovascular coverage. Multivariate regression analysis demonstrated chronic renal insufficiency to be independently associated with SCI (odds ratio [OR], 4.39; 95% confidence interval [CI], 1.2-16.6; P = .029). Onset of SCI occurred at a median of 10.6 hours (range, 0-229 hours) postprocedure and was delayed in 83% (n = 10) of patients. Clinical manifestations of SCI included lower extremity paraparesis in 9 patients and paraplegia in 3 patients. At SCI onset, average mean arterial pressure (MAP) and lumbar cerebrospinal fluid (CSF) pressure was 77 mm Hg and 10 mm Hg, respectively. Therapeutic interventions increased blood pressure to a significantly higher average MAP of 99 mm Hg (P = .001) and decreased lumbar CSF pressure to a mean of 7 mm Hg (P = .30) at the time of neurologic recovery. Thirty-day mortality was 8% (1 of 12 patients). The single patient who expired, never recovered any lower extremity neurologic function. All patients surviving to discharge experienced either complete (n = 9) or incomplete (n = 2) neurologic recovery. At mean follow-up of 49 months, 7 of 9 patients currently alive continued to exhibit complete, sustained neurologic recovery.

CONCLUSION

Spinal cord ischemia after TEVAR is an uncommon, but important complication. Preoperative renal insufficiency was identified as a risk factor for the development of SCI. Early detection and treatment of SCI with blood pressure augmentation alone or in combination with CSF drainage was effective in most patients, with the majority achieving complete, long-term neurologic recovery.

Preoperative total lymphocyte count in peripheral blood as a predictor of poor outcome in adult cardiac surgery

OBJECTIVE

The aim of this study was to investigate the prognostic value of the preoperative total lymphocyte count in peripheral blood as a predictor of postoperative complications and mortality in cardiac surgery.

DESIGN

A retrospective, observational study.

SETTING

The Novosibirsk State Research Institute of Circulation Pathology (single institution).

PARTICIPANTS

All adults undergoing primary cardiopulmonary bypass in 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The cohort size was 1,368 patients operated upon with cardiopulmonary bypass. Patient characteristics, hospital mortality, postoperative complications, ventilation time, intensive care unit, and hospital stay were analyzed. A preoperative total lymphocyte count <1,500 cells/μL was associated with significantly higher mortality by univariate (p < 0.0001) and multivariate (p < 0.044) analyses. A low preoperative total lymphocyte count was associated with more frequent inotropic support (p < 0.001); postoperative heart arrhythmia (p < 0.001); dialysis-dependent acute renal failure (p < 0.001); and a prolonged ventilation time (p = 0.001), intensive care unit stay (p < 0.001), and hospital stay (p = 0.007).

CONCLUSIONS

A low preoperative total lymphocyte count in peripheral blood is a useful prognostic criterion for the evaluation of a complicated postoperative period in cardiac patients operated under cardiopulmonary bypass.

Ischemic mitral regurgitation: a quantitative three-dimensional echocardiographic analysis

BACKGROUND

A comprehensive three-dimensional echocardiography based approach is applied to preoperative mitral valve (MV) analysis in patients with ischemic mitral regurgitation (IMR). This method is used to characterize the heterogeneous nature of the pathologic anatomy associated with IMR.

METHODS

Intraoperative real-time three-dimensional transesophageal echocardiograms of 18 patients with IMR (10 with anterior, 8 with inferior infarcts) and 17 patients with normal MV were analyzed. A customized image analysis protocol was used to assess global and regional determinants of annular size and shape, leaflet tethering and curvature, relative papillary muscle anatomy, and anatomic regurgitant orifice area.

RESULTS

Both mitral annular area and MV tenting volume were increased in the IMR group as compared with patients with normal MV (mitral annular area=1,065±59 mm2 versus 779±44 mm2, p=0.001; and MV tenting volume=3,413±403 mm3 versus 1,696±200 mm3, p=0.001, respectively). Within the IMR group, patients with anterior infarct had larger annuli (1,168±99 mm2) and greater tenting volumes (4,260±779 mm3 versus 2,735±245 mm3, p=0.06) than the inferior infarct subgroup. Papillary-annular distance was increased in the IMR group relative to normal; these distances were largest in patients with anterior infarcts. Whereas patients with normal MV had very consistent anatomic determinants, annular shape and leaflet tenting distribution in the IMR group were exceedingly variable. Mean anatomic regurgitant orifice area was 25.8±3.0 mm2, and the number of discrete regurgitant orifices varied from 1 to 4.

CONCLUSIONS

Application of custom analysis techniques to three-dimensional echocardiography images allows a quantitative and systematic analysis of the MV, and demonstrates the extreme variability in pathologic anatomy that occurs in patients with severe IMR.

Quantitative mitral valve modeling using real-time three-dimensional echocardiography: technique and repeatability

BACKGROUND

Real-time three-dimensional (3D) echocardiography has the ability to construct quantitative models of the mitral valve (MV). Imaging and modeling algorithms rely on operator interpretation of raw images and may be subject to observer-dependent variability. We describe a comprehensive analysis technique to generate high-resolution 3D MV models and examine interoperator and intraoperator repeatability in humans.

METHODS

Patients with normal MVs were imaged using intraoperative transesophageal real-time 3D echocardiography. The annulus and leaflets were manually segmented using a TomTec Echo-View workstation. The resultant annular and leaflet point cloud was used to generate fully quantitative 3D MV models using custom Matlab algorithms. Eight images were subjected to analysis by two independent observers. Two sequential images were acquired for 6 patients and analyzed by the same observer. Each pair of annular tracings was compared with respect to conventional variables and by calculating the mean absolute distance between paired renderings. To compare leaflets, MV models were aligned so as to minimize their sum of squares difference, and their mean absolute difference was measured.

RESULTS

Mean absolute annular and leaflet distance was 2.4±0.8 and 0.6±0.2 mm for the interobserver and 1.5±0.6 and 0.5±0.2 mm for the intraobserver comparisons, respectively. There was less than 10% variation in annular variables between comparisons.

CONCLUSIONS

These techniques generate high-resolution, quantitative 3D models of the MV and can be used consistently to image the human MV with very small interoperator and intraoperator variability. These data lay the framework for reliable and comprehensive noninvasive modeling of the normal and diseased MV.