Extensive aortic surgery in acute aortic dissection type A on outcome - insights from 25 years single center experience.

BACKGROUND: This single center study compares the different surgical techniques used in the treatment of acute aortic dissection type A (AADA) analyzing the influence of the extent of the surgical approach on outcome. METHODS: From 1988 to 2012, 407 patients were operated for AADA. The cohort was divided into subgroups according to the surgical approach. These groups were compared with the supracommissural replacement group (SCR; n = 141). Groups included aortic valve sparing techniques (AVS; n = 29), Composite replacement (COMP; n = 119), COMP with total arch replacement (COMP+TAR; n = 27) and SCR with TAR (n = 75). RESULTS: Compared to SCR alone, operation (p = 0.005), bypass-, cross-clamp and circulatory arrest times were longer in SCR + TAR (all p < 0.001). Moreover, operation, bypass and cross clamp times were longer in COMP+TAR (p = 0.003, p = 0.002 and p < 0.001 respectively). COMP alone and AVS required longer cross-clamp time, too (p < 0,001 and p = 0.002, respectively). Overall 30-day mortality was 21% with the observed lowest rate after AVS (14%, SCR 18%, COMP 25%) but differences in 30-day mortality were not statistically significant. The estimated 10-year survival was 42%, especially AVS demonstrated a good 10-year survival (69%). David technique was superior to Yacoub technique concerning incidence of redo interventions (p = 0.036). Risk factors for early mortality included age, circulatory arrest, general malperfusion, bypass and operation time. Circulatory arrest per se was revealed as risk factor for long-term survival. CONCLUSIONS: Within our single center retrospective study concomitant aortic root repair or aortic arch replacement for AADA demonstrated acceptable early and long-term survival. Circulatory arrest, long bypass and operation times per se might be important risk factors for early mortality. AVS techniques can be performed safely and have good outcomes in acute aortic dissection repair.

Investigation of raphe function in the bicuspid aortic valve and its influence on clinical criteria-A patient-specific finite element study.

The aortic valve is normally composed of 3 cusps. In one common lesion, 2 cusps are fused together. The conjoined area of the fused cusps is termed raphe. Occurring in 1% to 2% of the population, the bicuspid aortic valve (BAV) is the most common congenital cardiac malformation. The majority of BAV patients eventually require surgery. There is a lack in the literature regarding modeling of the raphe (geometry and material properties), its role and its influence on BAV function. The present study aims to propose improvements on these aspects. Three patient-specific finite element models of BAVs were created based on 3D trans-esophageal echocardiography measurements, and assuming age-dependent material properties. The raphe was initially given the same material properties as its underlying cusps. Two levels of validation were performed; one based on the anatomical validation of the pressurized geometry in diastole (involving 7 anatomical measures), as simulated starting from the unpressurized geometry, and the other based on a functional assessment using clinical measurements in both systole and diastole (involving 16 functional measures). The pathology was successfully reproduced in the FE models of all 3 patients. To further investigate the role of the raphe, 2 additional scenarios were considered; (1) the raphe was considered as almost rigid, (2) the raphe was totally removed. The results confirmed the interpretation of the raphe as added stiffness in the fused cusp's rotation with respect to the aortic wall, as well as added support for stress distribution from the fused cusps to the aortic wall.

Surgery for Infective Endocarditis: Outcomes and Predictors of Mortality in 360 Consecutive Patients.

BACKGROUND A retrospective analysis was conducted of the early and long-term outcomes after surgery for infective endocarditis (IE). MATERIAL AND METHODS We included 360 patients with IE operated upon between 1993 and 2012. The primary endpoint was overall cumulative postoperative survival at 30 days. Secondary endpoints were early postoperative outcomes and complication rates. Factors associated with 30-day mortality were analyzed. RESULTS Mean age was 58.7±14.7 years and 26.9% (n=97) were female. The mean follow-up was 4.41±4.53 years. Postoperative survival was 81.7% at 30 days, 69.4% at 1 year, 63.3% at 5 years, and 63.3% at 10 years. Non-survivors were significantly older (p=0.014), with higher NYHA Class (p=0.002), had higher rates of preoperative diabetes mellitus (p=0.005), renal failure (p=0.001), and hepatic disease (p=0.002). Furthermore, non-survivors had higher baseline alanine aminotransferase (ALT, p=0.048), aspartate transaminase (AST, p=0.027), bilirubin (p=0.013), white cell count (WCC, p=0.034), and CRP (p=0.049). Factors associated with 30-day mortality were longer duration of surgery, CPB, and aortic cross-clamping times (p<0.001, p<0.001, and p=0.003, respectively), as well as higher RBC, FFP, and platelet transfusion requirements (p<0.001, p=0.005, and p<0.001, respectively). Multivariate logistic regression analysis revealed liver cirrhosis (OR 4.583, 95-CI: 1.096-19.170, p=0.037) and longer CPB time (OR 1.025, 95-CI 1.008-1.042, p=0.004) as independent predictors of 30-day mortality. CONCLUSIONS Surgical treatment of IE shows satisfactory early, midterm, and long-term results. Multivariate logistic regression analysis revealed cirrhosis and longer CPB time as independent predictors of 30-day mortality.

Ischemic Colitis after Cardiac Surgery: Can We Foresee the Threat?

INTRODUCTION: Ischemic colitis (IC) remains a great threat after cardiac surgery with use of extracorporeal circulation. We aimed to identify predictive risk factors and influence of early catecholamine therapy for this disease. METHODS: We prospectively collected and analyzed data of 224 patients, who underwent laparotomy due to IC after initial cardiac surgery with use of extracorporeal circulation during 2002 and 2014. For further comparability 58 patients were identified, who underwent bypass surgery, aortic valve replacement or combination of both. Age ±5 years, sex, BMI ± 5, left ventricular function, peripheral arterial disease, diabetes and urgency status were used for match-pair analysis (1:1) to compare outcome and detect predictive risk factors. Highest catecholamine doses during 1 POD were compared for possible predictive potential. RESULTS: Patients' baseline characteristics showed no significant differences. In-hospital mortality of the IC group with a mean age of 71 years (14% female) was significantly higher than the control group with a mean age of 70 (14% female) (67% vs. 16%, p<0.001). Despite significantly longer bypass time in the IC group (133 ± 68 vs. 101 ± 42, p = 0.003), cross-clamp time remained comparable (64 ± 33 vs. 56 ± 25 p = 0.150). The majority of the IC group suffered low-output syndrome (71% vs. 14%, p<0.001) leading to significant higher lactate values within first 24h after operation (55 ± 46 mg/dl vs. 31 ± 30 mg/dl, p = 0.002). Logistic regression revealed elevated lactate values to be significant predictor for colectomy during the postoperative course (HR 1.008, CI 95% 1.003-1.014, p = 0.003). However, Receiver Operating Characteristic Curve calculates a cut-off value for lactate of 22.5 mg/dl (sensitivity 73% and specificity 57%). Furthermore, multivariate analysis showed low-output syndrome (HR 4.301, CI 95% 2.108-8.776, p<0.001) and vasopressin therapy (HR 1.108, CI 95% 1.012-1.213, p = 0.027) significantly influencing necessity of laparotomy. CONCLUSION: Patients who undergo laparotomy for IC after initial cardiac surgery have a substantial in-hospital mortality risk. Early postoperative catecholamine levels do not influence the development of an IC except vasopressin. Elevated lactate remains merely a vague predictive risk factor.

Female Gender and Differences in Outcome after Isolated Coronary Artery Bypass Graft Surgery: Does Age Play a Role?

INTRODUCTION: Female gender is a known risk factor for early and late mortality after coronary artery bypass graft surgery (CABG). Higher age of women at operation may influence outcome, since age per se is also an important risk factor. The purpose of our study was to analyze possible gender differences in outcome after isolated CABG in different age groups to delineate the impact of female gender and age. METHODS: All patients over 60 years of age undergoing isolated CABG at our department during 2001 and 2011 were included and categorized by age into sexagenarians (2266, 16.6% women), septuagenarians (2332, 25.4% women) and octogenarians (374, 32% women) and assessed by gender for 30-day and 180-day mortality. RESULTS: Thirty-day mortality was significantly higher in women only amongst septuagenarians (7.1 vs. 4.7%, p = 0.033). Same differences apply for 180-day mortality (12.3 vs. 8.2%, p = 0.033) and estimated one-year survival (81.6 ± 4.2 vs. 86.9 ± 2.2%, p = 0.001). Predictive factors for 30-day mortality of septuagenarian were logistic EuroSCORE (ES) (p = 0.003), perioperative myocardial infarction (MI) (p<0.001), pneumonia (p<0.001), abnormal LV-function (p<0.04) and use of LIMA graft (p<0.001), but not female gender. However, female gender was found to be an independent predictor for 180-day mortality (HR 1.632, p = 0.001) in addition to ES, use of LIMA graft, perioperative MI, pneumonia and abnormal LV function (HR 1.013, p = 0.004; HR 0.523, p<0.001; HR 2.710, p<0.001; HR 3.238, p<0.001; HR 2.013, p<0.001). CONCLUSION: Women have a higher observed probability of early death after CABG in septuagenarians. However, female gender was not found to be an independent risk factor for 30-day, but for 180-day survival. Therefore, reduction of high impact risk factors such as perioperative MI and enhancement of LIMA use should be future goals. In view of our findings, decision for surgical revascularization should not be based on gender.

Patients with systemic lupus erythematosus and antiphospholipid syndrome undergoing cardiac valve surgery.

BACKGROUND AND AIM OF THE STUDY: Systemic lupus erythematosus (SLE) and primary/secondary antiphospholipid syndrome (APLS) may cause early degenerative changes in cardiac valves, such as Libman-Sacks endocarditis, though few reports exist of this condition. Herein are presented the early and late clinical outcomes after cardiac valve surgery in patients diagnosed with SLE and APLS in a single-center experience. METHODS: A prospective analysis was conducted of the perioperative and follow up data acquired from patients with diagnosed SLE, and primary and secondary APLS, who underwent either single or combined valve surgery at the authors' department between 2002 and 2014. RESULTS: Fifteen patients (14 females, one male; mean age 53 ± 16 years; range: 16-77 years) were identified. The mean follow up time was 49 ± 32 months (range: 12.5-119 months). Thirteen patients (11 females, two males) were diagnosed with SLE; one of these patients had tricuspid Libman-Sacks endocarditis, while two female patients had primary APLS and four had secondary APLS. Besides bioprosthetic and mechanical valve replacements, mitral and tricuspid valve reconstruction were performed. The mean cross-clamp time was 112 ± 73 min (range: 55-294 min). Early major cardiovascular events occurred in two patients, and late non-fatal events in four patients, including one thromboembolic event. The 30-day and in-hospital mortalities were both 0%. Currently, 12 patients (80%) are alive at the end of follow up. Actuarial survival was 92 ± 7.4% at one year, 74 ± 18% at four years, and 49 ± 23% at ten years. CONCLUSION: Despite general concerns, the present results confirmed that patients with SLE and APLS can be operated on for cardiac valve disease, with favorable early results and acceptable long-term outcome.

Gender-specific differences in outcome of ascending aortic aneurysm surgery.

OBJECTIVES: Gender specific differences receive increasing attention and are known to affect the outcome of cardiovascular diseases. We investigated possible risk-factors for gender-specific differences in ascending aortic aneurysm surgery. METHODS: 548 consecutive patients (male: n = 390, age: 58.3 ± 14.4 years; female: n = 158, age: 65.3 ± 12.9 years) with aneurysms of the ascending aorta eligible for cardiac surgery were retrospectively analyzed. RESULTS: Women were significantly older when operation was indicated (p < 0.001) and presented with significantly more hypertension (p = 0.04) and chronic obstructive pulmonary disease (COPD; p = 0.017), whereas men had significantly more previous cardiac operations (p = 0.016). Normalized aortic diameters (diameter / body surface area) were significantly larger in women (3.10 ± 0.6 cm) vs. (2.75 ± 0,5 cm, p ≤ 0.001) in men, without differences in absolute values (5.74 ± 1.04 cm vs. 5.86 ± 1.34 cm). The aortic arch was significantly more involved in aneurysm formation in women (p = 0.04). Follow-up was available in 93% of the patients with a mean follow-up time of 3.9 ± 3.9 (0-17.8) years. 30-day mortality was 3.5% in men (n=12) and 7.9% in women (n = 11; p = 0.058). Univariate regression analysis shows gender specific risk factors for 30-day mortality in men to be age: p = 0.028; myocardial infarction: p = 0.0.24 and in women diameter of the ascending aorta: p = 0.014; renal insufficiency: p = 0.007. Long-term survival was significantly reduced in women (log-rank p = 0.0052). CONCLUSIONS: The outcome after surgery for ascending aortic aneurysm is less favourable in women with significantly reduced long-term survival and a trend to increased 30-day mortality in this cohort. Larger normalized aortic diameters, higher incidence of involvement of the aortic arch and differences in comorbidities may contribute to gender differences. Women undergo surgery at higher age and more progressed state of aortic disease. Therefore, gender-specific guidelines for ascending replacement may be useful to improve outcome in women.

Subject-specific finite-element modeling of normal aortic valve biomechanics from 3D+t TEE images.

In the past decades, developments in transesophageal echocardiography (TEE) have opened new horizons in reconstructive surgery of the aortic valve (AV), whereby corrections are made to normalize the geometry and function of the valve, and effectively treat leaks. To the best of our knowledge, we propose the first integrated framework to process subject-specific 3D+t TEE AV data, determine age-matched material properties for the aortic and leaflet tissues, build a finite element model of the unpressurized AV, and simulate the AV function throughout a cardiac cycle. For geometric reconstruction purposes, dedicated software was created to acquire the 3-D coordinates of 21 anatomical landmarks of the AV apparatus in a systematic fashion. Measurements from ten 3D+t TEE datasets of normal AVs were assessed for inter- and intra-observer variability. These tests demonstrated mean measurement errors well within the acceptable range. Simulation of a complete cardiac cycle was successful for all ten valves and validated the novel schemes introduced to evaluate age-matched material properties and iteratively scale the unpressurized dimensions of the valves such that, given the determined material properties, the dimensions measured in vivo closely matched those simulated in late diastole. The leaflet coaptation area, describing the quality of the sealing of the valve, was measured directly from the medical images and was also obtained from the simulations; both approaches correlated well. The mechanical stress values obtained from the simulations may be interpreted in a comparative sense whereby higher values are indicative of higher risk of tearing and/or development of calcification.

Treatment of ascending aortic aneurysms using different surgical techniques: a single-centre experience with 548 patients.

OBJECTIVES: The proper treatment of aneurysms of the ascending aorta is still under debate. Here, we describe the early and late outcomes after composite replacement (CR), supracommissural aortic replacement (SCR) and aortic valve-sparing (AVS) operations. METHODS: Five hundred and fourty-eight patients were operated on for ascending aortic aneurysm from 1994 until 2011. Two hundred and ninety-eight (54%) patients had CR, 154 (28%) underwent SCR, 96 (18%) received AVS using David's technique [83 (15%); after October 2006] and 13 (3%) using Yacoub's technique. The average size of the aneurysms was 5.8 ± 1.3 cm and differed between groups (P < 0.001). Patients in the SCR group were older (P < 0.001), and male gender was less frequent in the Yacoub group (P = 0.004). Marfan's syndrome was present more often in the AVS group (P < 0.001). RESULTS: Times for operation, extracorporeal circulation and aortic cross-clamping differed significantly (P < 0.001). In the SCR group, 40% of patients additionally underwent aortic valve replacement. Rethoracotomy for bleeding was required in 33 patients. Overall, 30-day mortality was 4.8% and did not differ between groups (SCR = 7.2%, CR = 4.8%, David's technique = 0% and Yacoub's technique = 8.3%; P = 0.12). Six patients experienced cerebral accidents. The follow-up was complete for 93%, and mean follow-up time was 3.9 ± 3.9 (0-17.8) years. Kaplan-Meier analysis revealed a significantly reduced long-term survival for women (log-rank P = 0.0052). Reoperation on the aortic root was necessary in only 6 patients from the Yacoub and SCR groups. No aortic dissection occurred. By uni- or multivariate regression analysis, age and preoperative creatinine were risk factors for 30-day mortality, and age, gender, creatinine, New York Heart Association class and chronic obstructive pulmonary disease, for long-term survival. CONCLUSIONS: All four applied techniques result in low mortality and low reoperation rate and prevent aortic dissection. The David procedure yields excellent mid-term results.

Mechanical characterization of human aortas from pressurization testing and a paradigm shift for circumferential residual stress.

Material properties needed for accurate stress analysis of the human aorta are still incompletely known, especially as many reports have ignored the presence of residual stresses in the aortic wall. To contribute new material regarding these issues, we carried out measurements and pressurization testing on ascending, thoracic and abdominal aortic samples from 24 human subjects aged 38-77 years, and evaluated the opening angle describing the circumferential residual stress level present in the aorta. We determined material constants for the aorta by gender, anatomic location and age group, according to a simple phenomenological constitutive model. The unpressurized aortic radius positively correlated with age, and the circumferential and longitudinal stretch ratios under systemic pressure negatively correlated with age, confirming the known enlargement and stiffening of the aorta with aging. The opening angle was measured to range from a minimum of 89° to above 360° for extreme cases. For given aortic dimensions and material properties, analysis of the in vivo circumferential and longitudinal mural stress distributions indicated a profound influence of the opening angle. For instance, in the thoracic aorta of males aged 38-66, opening angles in the range of 0° to 80° (resp. 60°) may equalize the gradient of in vivo circumferential (resp. longitudinal) stress between the inner and outer layers of the aorta, as commonly expected; however, opening angles above 160° (resp. 120°) may cause the gradient of circumferential (resp. longitudinal) stress to reverse and increase compared to the case without residual stress, putting the maximum stresses toward the adventitia instead of the intima. Even though the analysis of the aortic wall excluded possible longitudinal residual stresses as well as material inhomogeneities, such as constitutive differences between the intimal, medial and adventitial layers, the experimental data reported herein are important to aortic modeling at large and the better understanding of aortic pathophysiology in particular.

The groin first approach for transcatheter aortic valve implantation: are we pushing the limits for transapical implantation?

OBJECTIVE: Transcatheter aortic valve implantation (TAVI) is a therapeutic option for old and multimorbid patients with severe aortic stenosis. When applying the groin first approach by transfemoral implantation, patients in the transapical group are highly selected with even higher morbidity. We report outcome of the transapical group. METHODS: Between April 2008 and May 2011, 267 patients underwent TAVI through either a transfemoral (n = 201 CoreValve, n = 33 Edwards Sapien prostheses; mean age 81 ± 6 years, logistic EuroSCORE 19.5 ± 12.6 %; 4-76, STS score 7.2 ± 4 %; 1.5-28.9) or transapical approach (n = 33 Edwards Sapien prostheses; mean age 80 ± 1 years, logistic EuroSCORE 31.6 ± 17.1 %; 9.4-69.1, STS score 12.8 ± 7.1 %; 2.5-28.8). The transapical access was chosen only when transfemoral implantation was not possible. RESULTS: EuroSCORE and STS score were significantly higher in the transapical group (p = 0.001, respectively). A 30-day survival was comparable with 87.9 % in the transapical versus 92 % in the transfemoral group (p = 0.52). In the transapical group, female gender was predominant (n = 23; 70 %). Eight patients underwent previous cardiac surgery. All transapical implantations were successful. No bleeding or neurological complications occurred. Six patients required postoperative pacemaker implantation. Cardiac decompensation with concomitant pneumonia was the underlying cause for early mortality, except for one patient with abdominal malperfusion. Follow-up (0-37 months) was complete in 100 %, nine patients died after 30 days postoperatively (6 cardiac and 3 non-cardiac related). Echocardiography revealed good valve function with not more than mild paravalvular incompetence. CONCLUSIONS: Groin first approach is reasonable due to less invasive implantation technique. However, despite even higher predicted mortality, transapical aortic valve implantation is non-inferior to transfemoral approach.

Effects of FP15, a peroxynitrite decomposition catalyst on cardiac and pulmonary function after cardiopulmonary bypass.

OBJECTIVE: Peroxynitrite, a toxic nitrogen species, has been implicated in the development of ischemia/reperfusion injury. The aim of the present study was to investigate the effects of the potent peroxynitrite decomposition catalyst, FP15, on myocardial, endothelial, and pulmonary function in an experimental model of cardioplegic arrest and extracorporal circulation. METHODS: Twelve anesthetized dogs underwent hypothermic cardiopulmonary bypass. After 60 min of hypothermic cardiac arrest, reperfusion was started and either saline vehicle (control, n = 6) or FP15 (n = 6) was administered. Left-ventricular preload-recruitable stroke work (PRSW) was measured by a combined pressure-volume conductance catheter at baseline and after 60 min of reperfusion. Left anterior descending (LAD) coronary (CBF) and pulmonary blood flow (PBF), endothelium-dependent vasodilatation to acetylcholine (ACh), and alveolo-arterial O2 gradient were determined. RESULTS: The administration of FP15 led to a significantly better recovery of PRSW (given as percent of baseline: 93 ± 9 vs 62 ± 6%, p < 0.05). CBF was also significantly higher in the FP15 group (44 ± 6 vs 25 ± 4 ml min(-1), p < 0.05). Injection of ACh resulted in a significantly higher increase in CBF (70 ± 6 vs 35 ± 5%, p < 0.05) in the FP15-treated animals. The alveolo-arterial O2 gradient was significantly lower after FP15 administration (83 ± 7 vs 49 ± 6 mmHg, p < 0.05). Catalytic peroxynitrite decomposition did not affect baseline cardiovascular and pulmonary functions. CONCLUSIONS: Application of FP15 improves myocardial, endothelial, and pulmonary function after cardiopulmonary bypass with hypothermic cardiac arrest. The observed protective effects imply that catalytic peroxynitrite decomposition could be a novel therapeutic option in the treatment of ischemia/reperfusion injury.

Transcatheter aortic valve implantation after previous mechanical mitral valve replacement: expanding indications?

BACKGROUND: Cardiac operation for severe aortic stenosis after previous mitral valve replacement is a surgical challenge in older patients with multiple morbidities. Transcatheter aortic valve implantation (TAVI) after previous mechanical mitral valve replacement has been considered a high-risk procedure, owing to possible interference with the mitral valve prosthesis. METHODS: Since August 2008, 5 female high-risk patients with severe aortic stenosis and previous mitral valve replacement (mean ± SD age, 80 ± 5.1 years; logistic EuroSCORE, 39.3% ± 20.5%) underwent TAVI with a pericardial xenograft valve that was fixed with a stainless steel, balloon-expandable stent (Edwards Lifesciences SAPIEN). We used a transapical approach in 4 patients and a transfemoral approach in 1 patient. Transesophageal echocardiography and multidetector computed tomography were used for preoperative planning and assessment of operation feasibility. The mean distance between the aortic annulus and the mitral valve prosthesis was 10 ± 1 mm (range, 9-11 mm). RESULTS: TAVI was performed successfully in all 5 patients. There was no direct or functional interference with the mechanical mitral valve prostheses. Echocardiography revealed good valve function with no more than mild paravalvular incompetence early in the postoperative period and during routine follow-up. There were no neurologic events. After an initially uneventful course with good aortic valve function at the most recent echocardiography evaluation, however, 2 of the patients died from fulminant pneumonia on postoperative days 4 and 48. CONCLUSION: TAVI is technically feasible in high-risk patients after previous mechanical mitral valve replacement; however, careful patient selection is mandatory with respect to preoperative clinical status and anatomic dimensions regarding the distance between aortic annulus and mitral valve prosthesis.

Modeling leaflet correction techniques in aortic valve repair: A finite element study.

In aortic valve sparing surgery, cusp prolapse is a common cause of residual aortic insufficiency. To correct cusp pathology, native leaflets of the valve frequently require adjustment which can be performed using a variety of described correction techniques, such as central or commissural plication, or resuspension of the leaflet free margin. The practical question then arises of determining which surgical technique provides the best valve performance with the most physiologic coaptation. To answer this question, we created a new finite element model with the ability to simulate physiologic function in normal valves, and aortic insufficiency due to leaflet prolapse in asymmetric, diseased or sub-optimally repaired valves. The existing leaflet correction techniques were simulated in a controlled situation, and the performance of the repaired valve was quantified in terms of maximum leaflets stress, valve orifice area, valve opening and closing characteristics as well as total coaptation area in diastole. On the one hand, the existing leaflet correction techniques were shown not to adversely affect the dynamic properties of the repaired valves. On the other hand, leaflet resuspension appeared as the best technique compared to central or commissural leaflet plication. It was the only method able to achieve symmetric competence and fix an individual leaflet prolapse while simultaneously restoring normal values for mechanical stress, valve orifice area and coaptation area.

An alternative surgical approach for the combined treatment of pectus excavatum and acute aortic dissection type-A in Marfan syndrome.

Acute aortic dissection type-A (AADA) is a life-threatening condition especially in patients with Marfan syndrome (MFS) simultaneously suffering from severe pectus excavatum (PE). We report on emergency surgery for combined treatment of PE and AADA in a patient with MFS using an alternative approach. It leads to excellent exposure of the dislocated heart and great vessels enabling Bentall procedure followed by funnel chest repair with modified technique of Adkins and Blades. We achieved favorable functional and cosmetic results. Therefore, we conclude the surgical approach presented is feasible for standard treatment of AADA and consecutive repair of PE.

Usefulness and limitations of computational models in aortic disease risk stratification.

OBJECTIVE: In risk stratification of aortic diseases such as aneurysm and aortic dissection, diameter is one parameter whose influence on the average aortic wall stress is directly described by the Laplace law. More advanced mechanical models can be used and may yield additional information, such as transmural stress distributions. The question then arises of how refined models need to be to provide clinicians with practical help. METHODS: Two sets of finite element models were used. The relative roles of diameter, material stiffness, longitudinal stretch, blood pressure, wall thickness, and vessel curvature were explored using simplified aortic models for comparison with the Laplace law. The influences of the material properties nonlinearity and residual stress on the transmural stress distribution were investigated using an advanced aortic model including recent experimental findings in older humans. RESULTS: The Laplace law was confirmed as one effective, basic tool to assess the average wall stress in the aortic wall, both in the circumferential and longitudinal directions. However, the simplified models were sufficient to show that, as already reported in the literature, longitudinal stretch and vessel curvature have potentially equally strong or even stronger contributions to wall stress than the parameters included in the Laplace law. When the advanced model was used, and residual stress induced by large opening angles such as found in older subjects was introduced, the transmural stress gradient was found inverted compared with expectations, with the largest stresses now toward the adventitia. The results suggested that the intima may be increasingly shielded from higher stresses as one gets older, which might be protective against the initiation of dissection tears in the thoracic aorta. CONCLUSION: Biomechanical analysis of the aorta may be refined by using increasingly detailed computational models. Simplified models can readily improve on the Laplace law in the assessment of aortic wall stress, and as such, may already contribute to better risk stratification of aortic disease. Advanced models may also enhance our understanding of the mechanistic aspects in the pathogenesis of aortic disease. However, their applicability in a patient-specific context may be limited by the large number of input data they require, some of which might stay out of the clinicians' reach.

Structural analysis of the natural aortic valve in dynamics: from unpressurized to physiologically loaded.

A novel finite element model of the natural aortic valve was developed implementing anisotropic hyperelastic material properties for the leaflets and aortic tissues, and starting from the unpressurized geometry. Static pressurization of the aortic root, silicone rubber moulds and published data helped to establish the model parameters, while high-speed video recording of the leaflet motion in a left-heart simulator allowed for comparisons with simulations. The model was discretized with brick elements and loaded with time-varying pressure using an explicit commercial solver. The aortic valve model produced a competent valve whose dynamic behavior (geometric orifice area vs. time) closely matched that observed in the experiment. In both cases, the aortic valve took approximately 30 ms to open to an 800 mm(2) orifice and remained completely or more than half open for almost 200 ms, after which it closed within 30-50 ms. The highest values of stress were along the leaflet attachment line and near the commissure during diastole. Von Mises stress in the leaflet belly reached 600-750 kPa from early to mid-diastole. While the model using the unpressurized geometry as initial configuration was specially designed to satisfy the requirements of continuum mechanics for large deformations of hyperelastic materials, it also clearly demonstrated that dry models can be adequate to analyze valve dynamics. Although improvements are still needed, the advanced modeling and validation techniques used herein contribute toward improved and quantified accuracy over earlier simplified models.

Selective phosphodiesterase-5 inhibition reduces neointimal hyperplasia in rat carotid arteries after surgical endarterectomy.

OBJECTIVE: Long-term results of surgical vessel reconstruction are compromised by restenosis caused by neointimal hyperplasia. Recent studies suggest that reduced cyclic guanosine monophosphate signaling is associated with neointima formation. In a rat model of endarterectomy, we investigated the effect of pharmacologic inhibition of cyclic guanosine monophosphate degradation on neointima formation by using the selective phosphodiesterase-5 inhibitor vardenafil. METHODS: Carotid endarterectomy was performed in male Sprague-Dawley rats by means of incision of the right common carotid artery with removal of intima. Four groups were studied: unoperated control rats (n = 4), sham-operated rats (n = 9), control rats with endarterectomy (n = 9), or endarterectomized rats treated with vardenafil (10 mg/kg/day) postoperatively (n = 9). After 3 weeks, vessel compartment areas were measured by means of conventional microscopy with hematoxylin and eosin staining. Immunohistochemical analysis was performed to confirm neointima formation and the local cyclic guanosine monophosphate content. Plasma levels of cyclic guanosine monophosphate were determined by means of enzyme immunoassay. Student's t test was used for statistical evaluation. RESULTS: Immunohistochemical analysis demonstrated intensive staining for transforming growth factor beta1 and alpha-smooth muscle actin in the control neointima. Vardenafil significantly reduced the stenosis grade (24.64% +/- 7.46% vs 54.12% +/- 10.30% in the control group, P < .05) and expression of transforming growth factor beta1, as well as alpha-smooth muscle actin, in the neointima. The immunohistochemical score for cyclic guanosine monophosphate was higher in the treated neointima (4.80 +/- 0.76 vs 2.84 +/- 0.40 in the control group, P < .05), and increased plasma cyclic guanosine monophosphate levels were found by means of enzyme immunoassay as well (84.65 +/- 12.77 pmol/mL vs 43.50 +/- 3.30 pmol/mL in the control group, P < .05). CONCLUSIONS: Treatment with vardenafil can be considered a new possibility to prevent neointimal hyperplasia after endarterectomy.