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.

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.

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.

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.

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.

The peroxynitrite decomposition catalyst FP15 improves ageing-associated cardiac and vascular dysfunction.

Overproduction of oxidants and free radicals in ageing tissues induces nitro-oxidative stress, which has recently been implicated in the pathogenesis of cardiovascular dysfunction associated with ageing. Peroxynitrite, a strong cytotoxic oxidant damages proteins and DNA and activates several pathways causing tissue injury, including the peroxynitrite-poly(ADP-ribose) polymerase (PARP) pathway. In this study, we investigated the effectiveness of the peroxynitrite decomposition catalyst FP15 on ageing-associated cardiac and vascular dysfunction. Young and ageing rats were treated with vehicle or FP15 intraperitoneally. Using a microtip Millar pressure catheter we performed left ventricular blood pressure analysis to assess systolic and diastolic function. Endothelium-dependent and -independent vasorelaxation of isolated aortic rings were investigated by using acetylcholine and sodium nitroprusside. Ageing animals showed a marked reduction of systolic and diastolic cardiac function and loss of endothelium-dependent relaxant responsiveness of aortic rings. FP15-treatment significantly improved cardiac performance and endothelial function. Immunohistochemical staining confirmed that FP15 effectively reduced nitrosative stress and prevented the activation of PARP in the aortic wall of ageing rats. Our results demonstrate the importance of endogenous peroxynitrite-overproduction in the pathogenesis of ageing-associated cardiovascular dysfunction. Pharmacological decomposition of peroxynitrite by FP15 may represent a novel therapeutic utility to improve cardiac and vascular dysfunction associated with ageing.

Aortic valve leaflet sizer: a new device for aortic valve sparing.

In aortic valve-sparing surgery, the native valve of the patient is left in place but may need correction of its dimensions in order to regain full competence. A sizer was designed that can simultaneously measure the leaflet height and free edge length. A prototype was built and successfully used in porcine hearts of various sizes. The sizer is easy to use and provides dependable measurement of the aortic leaflet dimensions. Moreover, it represents a new resource on which surgeons may draw on to perform aortic valve-sparing surgery, with a better outcome for the patients.

Poly(ADP-ribose) polymerase inhibition reverses vascular dysfunction after gamma-irradiation.

PURPOSE: The generation of reactive oxygen species during gamma-irradiation may induce DNA damage, leading to activation of the nuclear enzyme poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) culminating in endothelial dysfunction. In the present study, we assessed the effect of PARP inhibition on changes in vascular function after acute and short-term irradiation. METHODS AND MATERIALS: In the acute experiments, aortic rings were exposed to 20 Gy of gamma-irradiation. The aortae were harvested after 1 or 7 days. Two additional groups received the ultrapotent PARP inhibitor, INO-1001, for 1 or 7 days after irradiation. The aortic rings were precontracted by phenylephrine and relaxation to acetylcholine and sodium nitroprusside were studied. RESULTS: The vasoconstrictor response to phenylephrine was significantly lower both acutely and 1 and 7 days after irradiation. Vasorelaxation to acetylcholine and sodium nitroprusside was not impaired acutely after irradiation. One and seven days after irradiation, vasorelaxation to acetylcholine and sodium nitroprusside was significantly enhanced. Treatment with INO-1001 reversed vascular dysfunction after irradiation. CONCLUSION: Vascular dysfunction was observed 1 and 7 days after irradiation, as evidenced by reduced vasoconstriction, coupled with endothelium-dependent and -independent hyperrelaxation. PARP inhibition restored vascular function and may, therefore, be suitable to reverse vascular dysfunction after irradiation.

Poly(ADP-ribose) polymerase inhibition combined with irradiation: a dual treatment concept to prevent neointimal hyperplasia after endarterectomy.

PURPOSE: In a rat model of endarterectomy we investigated the potential role of the peroxynitrite-poly(ADP-ribose) polymerase (PARP) pathway in neointima formation and the effects of irradiation, pharmacologic inhibition of PARP, or combined pharmacologic inhibition of PARP and irradiation on vascular remodeling. METHODS AND MATERIALS: Carotid endarterectomy was performed by incision of the left carotid artery with removal of intima in Sprague-Dawley rats. Six groups were studied: sham-operated rats (n = 10), control endarterectomized rats (n = 10), or endarterectomized rats irradiated with 15 Gy (n = 10), or treated with PARP inhibitor, INO-1001 (5 mg/kg/day) (n = 10), or with combined treatment with INO-1001 and irradiation with 5 Gy (n = 10) or with 15 Gy (n = 10). After 21 days, neointima formation and vascular remodeling were assessed. RESULTS: Neointima formation after endarterectomy was inhibited by postoperative irradiation with 15 Gy and was attenuated by PARP inhibition. However, in parallel to inhibition of neointimal hyperplasia, activation of the peroxynitrite-PARP pathway in the outer vessel wall layers was triggered by postoperative irradiation. Combined pharmacologic PARP inhibition and irradiation with 15 Gy significantly reduced both neointimal hyperplasia and activation of the peroxynitrite-PARP pathway in the outer vessel wall layers. Combination of PARP inhibition and irradiation with 5 Gy was less effective than both PARP inhibition or irradiation with 15 Gy alone. CONCLUSIONS: We conclude, that combined PARP inhibition and irradiation with 15 Gy may be a new dual strategy for prevention of restenosis after surgical vessel reconstruction: combining the strong antiproliferative effect of irradiation and ameliorating irradiation-induced side effects caused by excessive PARP activation.

Geometric modeling of functional trileaflet aortic valves: development and clinical applications.

The dimensions of the aortic valve components condition its ability to prevent blood from flowing back into the heart. While the theoretical parameters for best trileaflet valve performance have already been established, an effective approach to describe other less optimal, but functional models has been lacking. Our goal was to establish a method to determine by how much the dimensions of the aortic valve components can vary while still maintaining proper function. Measurements were made on silicone rubber casts of human aortic valves to document the range of dimensional variability encountered in normal adult valves. Analytical equations were written to describe a fully three-dimensional geometric model of a trileaflet valve in both the open and closed positions. A complete set of analytical, numerical and graphical tools was developed to explore a range of component dimensions within functional aortic valves. A list of geometric guidelines was established to ensure safe operation of the valve during the cardiac cycle, with practical safety margins. The geometry-based model presented here allows determining quickly if a certain set of valve component dimensions results in a functional valve. This is of great interest to designers of new prosthetic heart valve models, as well as to surgeons involved in valve-sparing surgery.

Adjunct brachytherapy: a new concept to prevent intimal hyperplasia after surgical endarterectomy?

OBJECTIVE: Endarterectomy represents a therapeutical option for patients with advanced coronary artery disease. The mid-term results are compromised by restenosis due to neointima formation. The aim of this study was to evaluate a new treatment concept - endarterectomy with consecutive gamma-irradiation - in a rat model. METHODS: Male Sprague-Dawley rats underwent left carotid endarterectomy with removal of intima: control (n=10) or were irradiated with 15 Gray (Gy) (n=13) or 20 Gy (n=10) postoperatively and compared with sham-operated rats (n=10). After 3 weeks, carotid arteries were perfusion-fixed and vessel compartment areas were measured. Transmission electron microscopy and immunohistochemical staining were used to confirm neointima formation. RESULTS: Three weeks after endarterectomy, neointimal hyperplasia was found in the control group (0.07+/-0.04 mm(2)). After irradiation, a dose-dependent reduction of neointima was observed (0.003 mm(2) at 15 Gy and 0.0007 mm(2) at 20 Gy, P<0.0001). However, immunohistochemical staining revealed that thin re-endothelialization after irradiation was not inhibited. CONCLUSIONS: Gamma-irradiation significantly suppressed neointimal hyperplasia in a rat model of surgical endarterectomy. Despite inhibition of intimal hyperplasia, re-endothelialization after adjuvant brachytherapy was present. Adjuvant brachytherapy may be therefore a new concept to prevent restenosis after endarterectomy in patients.

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.

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.

Role of aortic root motion in the pathogenesis of aortic dissection.

BACKGROUND: The downward movement of the aortic root during the cardiac cycle may be responsible for producing the circumferential tear observed in aortic dissections. METHODS AND RESULTS: Contrast injections were investigated in 40 cardiac patients, and a finite element model of the aortic root, arch, and branches of the arch was built to assess the influence of aortic root displacement and pressure on the aortic wall stress. The axial displacement of the aortic root ranged from 0 to 14 mm. It was increased in patients with aortic insufficiency (22+/-13% of the sino-tubular junction diameter versus 12+/-9%) and reduced in patients with hypokinesis of the left ventricle (10+/-9% of sino-tubular junction versus 17+/-12%). The largest stress increase due to aortic root displacement was found approximately 2 cm above the sino-tubular junction, where the longitudinal stress increased by 50% to 0.32 Nmm(-2) when 8.9-mm axial displacement was applied in addition to 120-mm Hg luminal pressure. A similar result was observed when the pressure load was increased to 180 mm Hg without axial displacement. CONCLUSIONS: Both aortic root displacement and hypertension significantly increase the longitudinal stress in the ascending aorta. For patients with hypertension who are at risk of dissection, aortic root movement may be monitored as an important risk factor.

Are there surgical implications to aortic root motion?

BACKGROUND AND AIM OF THE STUDY: By increasing the longitudinal stress in the ascending aorta, downward movement of the aortic root might promote the proximal transverse tears seen in aortic dissections. The study aim was to evaluate the influence of five common cardiac conditions on the magnitude of aortic root displacement in cardiac patients. METHODS: Aortic root contrast injections were analyzed in 90 patients (mean age 68 years) to measure downward motion of the root perpendicular to the plane of the sinotubular junction (STJ). RESULTS: Displacement of the aortic root ranged from 0 to 14 mm (mean 4.8 mm). Patients with aortic insufficiency (AI) showed increased aortic root movement (7.3 versus 4.3 mm, p = 0.003), whereas those with left ventricular hypokinesis (3.7 versus 5.5 mm, p = 0.014) or with myocardial hypertrophy (3.8 versus 5.1 mm, p = 0.073) exhibited reduced downward movement. These variables were independent, and correlated with the magnitude of aortic root motion. A stress analysis of the aortic root, arch and branches of the arch determined that the longitudinal stress approximately 2 cm above the STJ, in the outer curve of the aorta, was increased by 32% in patients with AI compared to patients without AI. CONCLUSION: Patients with cardiac conditions associated with increased aortic root motion such as AI may be at greater risk of aortic dissection because of increased longitudinal stress in the ascending aorta. Therefore, AI should be used as an indicator and aortic root displacement monitored to prevent the risk of aortic dissection.

Increased aortic wall stress in aortic insufficiency: clinical data and computer model.

OBJECTIVE: The study was aimed at determining which cardiac pathologies are associated with increased longitudinal stress in the aorta and therefore may be responsible for the intimal transverse tears seen in aortic dissections. METHODS: Aortic root contrast injections were analyzed in 90 cardiac patients to measure the downward motion of the annulus during a cardiac cycle. A finite element model of the pressurized aortic root, arch and supra-aortic vessels was created to assess the influence of the aortic root motion on the aortic wall stress. RESULTS: The axial displacement of the aortic root ranged from 0 to 14 mm. A multivariate analysis showed that aortic insufficiency (AI) grade, hypokinesis of the left ventricle (HKI), and myocardial hypertrophy (HTR) were 3 independent variables which correlated with the axial displacement of the aortic root (DISP), such that ARM (mm)=5.379 (P<0.0001) +1.186 x AI grade (P=0.0016) - 1.611 x HKI (P=0.0078) - 1.399 x HTR (P=0.0355) with R2=0.23. The major finding of the stress analysis was that in the ascending aorta, at approximately 2 cm above the sino-tubular junction, the longitudinal stress due to aortic root motion was 32% higher in patients with AI than in patients without AI, thereby increasing the risk of transverse intimal rupture. CONCLUSIONS: Cardiac patients with AI are likely to experience enhanced longitudinal stress in the ascending aorta due to increased aortic root motion. Thus, these patients should be targeted and their aortic root movement monitored because it may be an important risk factor for aortic dissection.

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.

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.

Preoperative high leukocyte count: a novel risk factor for stroke after cardiac surgery.

BACKGROUND: Stroke after cardiac surgery is a devastating complication. The relationship between white blood cell count (WBC) and perioperative cerebrovascular accident (CVA) has not been investigated. An effort was made to identify how preoperative WBC may relate to CVA development during or after cardiac surgery. METHODS: Prospective data were collected from 7,483 patients who underwent coronary artery bypass grafting or valvular surgery or both. WBC was determined preoperatively and postoperatively. Differentiation of WBC was examined only preoperatively. RESULTS: There were a total of 125 CVAs (10 transient ischemic attacks [TIAs], 115 strokes). WBC was significantly higher preoperatively and directly postoperatively in patients with stroke. Qualitative changes in preoperative WBC were also found in these patients (chi2; p < 0.001). The predictive power of the stepwise logistic regression model for CVA was greater when preoperative WBC was included. The risk for perioperative CVA increased starting at preoperative WBC of 9 x 10(9)/L (p = 0.044) and progressed in higher WBC ranges. WBC had a significant impact on CVA outcome (analysis of variance, p = 0.001). CONCLUSIONS: Our studies have established the correlation between high preoperative WBC and stroke during or after cardiac surgery. Furthermore, elevated preoperative WBC was related to the clinical outcome of CVA. Preoperative measures aimed at preventing or treating conditions such as infections that may cause elevated WBC may be beneficial in the prevention of stroke during or after cardiac surgery.