Lack of definite indication criteria for choosing between transcatheter implantation and surgical replacement of the aortic valve.

AIMS: Age over 75 years and logistic Euroscore over 20% have been jointly proposed by European scientific associations as the criteria for aortic valve stenosis patients to be considered 'high-risk' for surgical aortic valve replacement (AVR) and candidates for transcatheter aortic valve implantation (TAVI). We aimed to verify traditional AVR outcomes in the presence of the above criteria. METHODS: Between January 2001 and January 2011, 180 patients with severe aortic valve stenosis (mean aortic valve area = 0.4±0.1 cm/m), with age range 75-88 years (mean 78.2±3), logistic Euroscore between 4.5 and 40% (mean 12.6±7.4%), underwent surgical AVR. The patient population was divided into group A (118 patients between 75 and 79 years of age), further divided into subgroups A1 (76 patients) and A2 (42 patients) with logistic Euroscore, respectively, less than 20% and at least 20%; and group B (62 patients between 80 and 88 years of age), subdivided into B1 (34 patients) and B2 (28 patients) with logistic Euroscore, respectively, less than 20% and at least 20%. Hospital outcomes were retrospectively evaluated. Univariate and multivariate analyses, including age and logistic Euroscore, were performed to individuate predictors of hospital mortality. RESULTS: Overall observed/expected mortality ratio was 0.4. Hospital mortality was 5.3% in group A1, 4.8% in A2, 5.9% in B1, 3.6% in B2 (P=NS). Mortality with age over 75 and Euroscore at least 20% was 4.3%. As regards postoperative morbidity, atrio-ventricular bock indicating pacemaker implantation occurred in four patients, pneumonia in three, stroke in two, perioperative myocardial infarction in one. Age and Euroscore were not independent predictors of mortality, morbidity or composite endpoint in multivariable analysis. CONCLUSION: Age and logistic Euroscore might be inadequate criteria for the identification of patients with severe aortic stenosis unsuitable for AVR and addressable to TAVI.

Early cell changes and TGFß pathway alterations in the aortopathy associated with bicuspid aortic valve stenosis.

Previous studies on BAV (bicuspid aortic valve)-related aortopathy, whose aetiology is still debated, have focused mainly on severe dilatations. In the present study, we aimed to detect earlier signs of aortopathy. Specimens were collected from the 'concavity' (lesser curvature) and the 'convexity' (greater curvature) of mildly dilated AAs (ascending aortas; diameter ≤4 cm) with stenotic TAV (tricuspid aortic valve) or BAV and from donor normal aortas. Specimens were submitted to morphometry, immunohistochemistry and differential gene-expression analysis, focusing on SMC (smooth muscle cell) phenotype, remodelling, MF (myofibroblast) differentiation and TGFß (transforming growth factor ß) pathway. Smoothelin and myocardin mRNAs decreased in all the samples from patients, with the exception of those from BAV convexity, where a change in orientation of smoothelin-positive SMCs and an increase of α-SMA (α-smooth muscle actin) mRNA occurred. Dilated aortas from BAV and TAV patients showed both shared and distinct alterations concerning the TGFß pathway, including an increased TGFß and TGFßR2 (TGFß receptor 2) expression in both groups and a decreased TGFßR1 expression in BAV samples only. Despite a decrease of the mRNA coding for the ED-A (extra domain-A) isoform of FN (fibronectin) in the BAV convexity, the onset of the expression of the corresponding protein in the media was observed in dilated aortas, whereas the normal media from donors was negative for this isoform. This discrepancy could be related to modifications in the intima, normally expressing ED-A FN and showing an altered structure in mild aortic dilatations in comparison with donor aorta. Our results suggest that changes in SMC phenotype and, likely, MF differentiation, occur early in the aortopathy associated with valve stenosis. The defective expression of TGFßR1 in BAV might be a constitutive feature, while other changes we reported could be influenced by haemodynamics.

Apico-aortic conduit for severe hypertrophic cardiomyopathy: sudden death despite conduit patency 31 years postoperatively.

Although small experiences have been described with the use of apico-aortic valved conduit in the treatment of hypertrophic cardiomyopathy (HCM), the long-term follow-up has never been previously reported. In a young female patient with symptomatic HCM and a prognostically unfavorable phenotype, apico-aortic conduit was chosen instead of conventional myectomy because severe ventricular hypertrophy involved the whole ventricle, making outflow tract cavity virtually absent in systole. Close clinical and imaging follow-up was postoperatively performed. The patient remained asymptomatic, without cardioactive drug therapy for 30 years, also experiencing 2 successful pregnancies. A striking finding was the perfect patency of the conduit at the last follow-up control (31 years), with computed tomography and echocardiography showing no calcification of the porcine Hancock bioprosthesis inside the graft. Nevertheless, the disease slowly evolved towards the dilative phase and the patient experienced sudden death while scheduled for implantation of defibrillator in waiting list for heart transplant.The present case could suggest that, in selected cases of HCM not treatable by myectomy, apico-aortic conduit may be an option. The relief of the obstruction can provide even long-term freedom from symptoms, however, late evolution to end-stage cannot be prevented.

Hemostatic modifications of the Bentall procedure: imbricated proximal suture and fibrin sealant reduce postoperative morbidity and mortality rates.

Bleeding is an important predictor of morbidity and mortality rates after the Bentall operation. This study reports our recent experience with composite aortic root replacement via a slightly modified button-Bentall operation. Fifty-six consecutive patients underwent a Bentall operation on an elective basis from January 2008 through December 2009. In all cases, we used 2 modifications: we imbricated the pledgeted 2-0 polyester interrupted U stitches of the proximal suture line, and at that same suture line we sealed with fibrin glue the possible sources of oozing. The series featured high proportions of associated procedures (25%) and reoperations (23%). The mean cardiopulmonary bypass and aortic cross-clamp times were 166 ± 50 and 113 ± 27 min, respectively. No case of operative or hospital (30-day) death was observed. Postoperative drainage amounted to 705 mL (median) on the first postoperative day and 377 mL (mean) on the second. Surgical re-exploration for bleeding was needed in only 1 patient (1.8%). Postoperative acute kidney injury was observed in 5 patients, neurologic complications in 3, and respiratory insufficiency requiring prolonged mechanical ventilation in another 3. Both respiratory and renal complications were significantly associated with greater consumption of blood products (P=0.03 and P=0.001, respectively). We conclude that the combined use of imbricated proximal suture-line stitches and subsequent fibrin-sealant spraying were associated with no deaths and with low rates of bleeding and other adverse postoperative sequelae in our 2-year experience with the Bentall operation in an elective series of patients characterized by a difficult mixture of prognoses.

The need for a specific risk prediction system in native valve infective endocarditis surgery.

The need for a specific risk score system for infective endocarditis (IE) surgery has been previously claimed. In a single-center pilot study, preliminary to future multicentric development and validation, bivariate and multivariate (logistic regression) analysis of early postoperative mortality predictors in 440 native valve IE patients were performed. Mathematical procedures assigned scores to the independent predictors emerged (AUC of the ROC curve: 0.88). Overall mortality was 9.1%. Six predictors were identified and assigned scores, including age (5-13 points), renal failure (5), NYHA class IV (9), critical preoperative state (11), lack of preoperative attainment of blood culture negativity (5), perivalvular involvement (5). Four risk classes were drawn ranging from "very low risk" (≤5 points, mean predicted mortality 1%), and to "very high risk" (≥20 points, 43% mortality). IE-specific risk stratification models are both needed, as disease-specific factors (e.g., cultures, abscess), beside the generic ones (e.g., age, renal impairment) affect mortality, and feasible.

Mechanical aortic valve replacement in young women planning on pregnancy: maternal and fetal outcomes under low oral anticoagulation, a pilot observational study on a comprehensive pre-operative counseling protocol.

OBJECTIVES: This pilot prospective observational study aimed to evaluate the maternal and fetal outcomes of pregnancies under low-dose oral anticoagulation therapy after aortic mechanical replacement. BACKGROUND: Need for valve replacement is still an issue for young women with native valve disease who are planning on future pregnancy. Choice of replacement device is a challenging clinical task. METHODS: A comprehensive pre-operative counseling protocol to guide choice of replacement device was developed. The pre-operative anticoagulation trial to determine the warfarin daily dosage needed to reach target international normalized ratio (INR) represented the main stem of such protocol. Pregnancies on low-dose anticoagulation therapy (target INR: 1.5 to 2.5) were allowed in a highly selected subset of mechanical aortic valve recipients. RESULTS: Twenty-two patients of 40 originally referred for native valve disease surgery requiring valve replacement, safely underwent the pre-operative anticoagulation challenge. No maternal or fetal complications were detected in 16 pregnancies under low oral anticoagulation. Patterns of warfarin daily dosage and induced INRs were characterized during pregnancy. CONCLUSIONS: In this small sample observational study, a pre-operative anticoagulation therapy trial helped young women scheduled for valve replacement to acquire complete information as to the choice of prosthetic device. In selected third-generation mechanical aortic prosthesis recipients, low-dose anticoagulation therapy seems safe and feasible for both mother and fetus. Further studies are needed to validate this approach.

Coronary artery bypass grafting associated to aortic valve replacement in the elderly: survival and quality of life.

Myocardial ischemia is often associated to aortic valve stenosis in the elderly. Aim of this study was to evaluate the impact on survival and quality of life of CABG associated to aortic valve replacement in the septuagenarians and octogenarians.Between January 1991 and January 2010, 520 patients ageing > 70 years underwent aortic valve replacement with a mechanical prosthesis in two Institutions. They were divided into 2 groups: Group A included 406 patients undergoing isolated aortic valve replacement; Group B 114 patients receiving aortic valve replacement and CABG. A comparative analysis of long-term survival and quality of life (SF-36 test) was performed.Mean age was 74.2 ± 3.6 years (74.3 ± 3.6 in Group A, 74 ± 3.3 in Group B; p = 0.33). Hospital mortality was 9.5% (46 patients). Twenty-nine (7.8%) in Group A and 17 in Group B (15.2%)(p = 0.019). Actuarial survival was 88.5% ± 0.015 at 1 year, 81.9% ± 0.02 at 5 years, 76.6% ± 0.032 at 10 and 57.3 ± 0.1 at 15 years. Ten-year survival was 77% ± 0.034 in Group A and 77.8% ± 0.045 in Group B (p = 0.2). Multivariate analysis did not reveal associated CABG as a predictor of long term mortality. The scores obtained in the SF-36 test were similar in the two groups and significantly higher than those of the general population matched for country, age and sex (p < 0.001 in all domains).Associated CABG determines a significant increase of hospital mortality in the elderly undergoing aortic valve replacement. Survivors did not show differences in long-term outcome and quality of life according to the presence of associated CABG.

Long-term follow-up of reduction ascending aortoplasty with autologous partial wrapping: for which patient is waistcoat aortoplasty best suited?

OBJECTIVES: The aim of this study was to assess the early and long-term outcomes of a previously introduced technique of reduction aortoplasty for asymmetric ascending aortic dilatation. Different indication criteria for reduction ascending aortoplasty have been previously adopted by others, thus another purpose was to identify the patient profile for whom this approach may be best suited. METHODS: Between January 2001 and December 2010, reduction ascending aortoplasty with "waistcoat technique" was performed in 156 patients (mean age 62 ± 12 years, 61% male) with asymmetric dilatation of the ascending aorta (prevailing at the convexity of the supracoronary tract). Eighty-seven patients had a tricuspid aortic valve (TAV), 69 a bicuspid aortic valve (BAV). Aortoplasty was associated to aortic valve replacement in 60% cases. Preoperative, intraoperative, early postoperative and follow-up data were analysed. Comparisons were performed between groups of valve morphology (TAV versus BAV) and subgroups of baseline valve function. In patients with a follow-up time >1 year the annual growth of the ascending tract was calculated and compared between subgroups. The independent predictors of growth velocity were assessed by multivariable linear regression analysis. RESULTS: Mean cross-clamp and cardiopulmonary bypass times were 39 ± 18 and 69 ± 29 min, respectively. Hospital death was 1.9%. In no case, postoperative death or any early complication was causally related to the aortoplasty procedure. The mean postoperative ascending diameter was 3.1 ± 0.3 (versus preoperative 5.2 ± 0.8 cm, P < 0.001). Mean follow-up time was 4 ± 2.5 years (maximum 10 years): 7-year survival was 95 ± 2%; 7-year freedom from aortic events 94 ± 4%. Redilatation (ascending diameter exceeding 4.5 cm) occurred in two patients, acute dissection in one: all three preoperatively had significant aortic regurgitation. The mean ascending aortic diameter at last follow-up was 3.4 ± 0.5 cm; median diameter progression was 0.4 mm/year, with no significant difference between TAV and BAV and no patient reaching 0.5 cm/year. With TAV, the only determinant of aortic growth rate was normal preoperative valve function (P = 0.04); with BAV, the degree of regurgitation at preoperative echocardiography (P = 0.001). CONCLUSIONS: Waistcoat aortoplasty proved a safe and durable treatment for patients with asymmetric non-syndromic non-familial ascending aorta dilatation. The technique showed its best durability in aortic stenosis patients and in patients with normofunctional BAV.

Aortic and left ventricular remodeling in patients with bicuspid aortic valve without significant valvular dysfunction: a prospective study.

BACKGROUND: Bicuspid aortic valve (BAV) represents the most common cardiac congenital malformation in the adult age. It is frequently associated with dilatation, aneurysm and dissection of the ascending aorta. The purpose of the following study was to evaluate in patients with BAV: 1) the elastic properties of the ascending aorta, 2) the mechanical function of the left ventricle and 3) stiffness, elasticity and strain of the epi-aortic vessels wall. METHODS: Forty BAV patients (28M/12F; age 20.9 ± 4.7 years; range 17-26) with no or mild valvular impairment were recruited with 40 control subjects (25M/15F; age 23.4 ± 3.4 years; range 15-31) matched for age, gender and body surface area (BSA). Aortic strain, aortic distensibility (AoDIS) and aortic stiffness index (AoSI) were derived. Left ventricular strain was acquired. Elastic properties of epi-aortic vessels were evaluated. RESULTS: BAVs vs. controls had increased systolic and diastolic aortic diameters (p<0.001). Aortic strain (%) was lower in BAVs than in controls (8.3 ± 3.6 vs. 11.2 ± 2.6; p<0.001) as well as AoDIS (10(-6)cm(2)dyn(-1)) (6.5 ± 2.8 vs. 8.8 ± 2.9; p=0.002), while AoSI was greater in BAVs (6.4 ± 3.5 vs. 3.9 ± 1.2; p<0.001). Both AoDIS and aortic strain were related to aortic size in BAVs and controls. Left ventricular longitudinal (p=0.01), circumferential (p=0.01) and radial (p<0.001) strain (%) were lower in BAVs. No significant differences were found in elastic properties of epi-aortic vessels. CONCLUSIONS: Bicuspid aortic valve is associated with an increased aortic stiffness and with a reduction of the aortic and left ventricular deformation properties. Epi-aortic vessels do not seem to be interested by the disease. The use of an echocardiographic method that can estimate the degree of aortic and left ventricular remodeling can provide great benefits in the selection of patients with BAV to be treated and in determining the time for beginning drug therapy.

Restricted cusp motion in right-left type of bicuspid aortic valves: a new risk marker for aortopathy.

OBJECTIVE: Bicuspid aortic valve disease is heterogeneous with respect to valve morphology and aortopathy risk. This study searched for early imaging predictors of aortopathy in patients with a bicuspid aortic valve with right-left coronary cusp fusion, the most common morphotype. METHODS: Time-resolved magnetic resonance imaging was performed in 36 subjects with nonstenotic, nonregurgitant bicuspid aortic valves and nondilated aortas and in 10 healthy controls with tricuspid aortic valves. Sinus dimensions (diameter, width, and height), ascending tract diameters, and wall strain were measured for each sinus/leaflet unit and corresponding ascending tract area to account for asymmetries. A novel parameter, "cusp opening angle," measured the degree of valve leaflet alignment to outflow axis in systole, quantifying cusp motility. Phase-contrast magnetic resonance imaging and computational fluid dynamic models assessed flow patterns. Aortic growth rate was estimated over a follow-up period ranging from 9 to 84 months. RESULTS: The expected restriction of bicuspid aortic valve opening (conjoint cusp opening angle, 62°±5° vs 76°±3° for nonfused leaflet and 75°±3° for tricuspid aortic valve cusps; P<.001) was confirmed, and the introduced parameter reproducibly quantified this phenomenon. Phase-contrast magnetic resonance imaging demonstrated systolic flow deflection toward the right, affecting the right anterolateral ascending wall. Computational models confirmed that restricted cusp motion alone is sufficient to cause the observed flow pattern. Ascending tract wall strain was not circumferentially homogeneous in bicuspid aortic valves. In multivariable analyses, the conjoint cusp opening angle independently predicted ascending aorta diameters and growth rate (P<.001). CONCLUSIONS: In the bicuspid aortic valve commonly defined as normofunctional by echocardiographic criteria, restricted systolic conjoint cusp motion causes flow deflection. The novel measurement introduced can quantify restricted cusp opening, possibly assuming prognostic importance.

Aortic erosion during negative pressure therapy in a pediatric heart transplant recipient.

A happy-ending "series of unfortunate events" is reported of the successful emergency treatment of an erosion of the ascending aorta during negative pressure sternal wound therapy for a relapse of Berlin Heart driveline infection in a pediatric transplant recipient. Several key issues related to assist device-related infections and negative pressure complications are discussed in this peculiar setting.

Is post-sternotomy mediastinitis still devastating after the advent of negative-pressure wound therapy?

In this study, we reviewed a 15-year experience with the treatment of a severe sequela of cardiac surgery: post-sternotomy mediastinitis. We compared the outcomes of conventional treatment with those of negative-pressure wound therapy, focusing on mortality rate, sternal reinfection, and length of hospital stay.We reviewed data on 157 consecutive patients who were treated at our institution from 1995 through 2010 for post-sternotomy mediastinitis after cardiac surgery. Of these patients, 74 had undergone extensive wound débridement followed by negative-pressure wound therapy, and 83 had undergone conventional treatment, including primary wound reopening, débridement, closed-chest irrigation without rewiring, topical application of granulated sugar for recurrent cases, and final plastic reconstruction with pectoral muscle flap in most cases.The 2 study groups were homogeneous in terms of preoperative data and operative variables (the primary cardiac surgery was predominantly coronary artery bypass grafting). Negative-pressure wound therapy was associated with lower early mortality rates (1.4% vs 3.6%; P = 0.35) and significantly lower reinfection rates (1.4% vs 16.9%; P = 0.001). Significantly shorter hospital stays were also observed with negative pressure in comparison with conventional treatment (mean durations, 27.3 ± 9 vs 30.5 ± 3 d; P = 0.02), consequent to the accelerated process of wound healing with negative-pressure therapy.Lower mortality and reinfection rates and shorter hospital stays can result from using negative pressure rather than conventional treatment. Therefore, negative-pressure wound therapy is advisable as first-choice therapy for deep sternal wound infection after cardiac surgery.

Radical and harmless shave resection of atypical papillary fibroelastomas of the cardiac valves.

BACKGROUND: Papillary fibroelastomas (PFEs) are rare cardiac tumors usually treated by shave resection. Up to 20% of the patients are actually denied such a conservative surgical approach because atypical morphology is thought to preclude radical and effective outcomes. METHODS/RESULTS: Surgical tricks and tips of shave resection are elucidated, and a case series presentation of the morphology of atypical PFEs treated by shave resection is described. CONCLUSION: In experienced hands surgical shave resection is the gold standard for the treatment of PFE even in atypical presentations.

Environmental pollution as a cause of papillary fibroelastoma: hints for a new etiological hypothesis?

BACKGROUND: Environmental pollution has adverse human health effects, mostly on the respiratory tract but also on the cardiovascular system. Papillary fibroelastomas are exceedingly rare primary cardiac tumors; their pathologic origin remains still elusive. CASE REPORT: This is a brief report on 3 patients referred for surgical treatment of papillary fibroelastomas in the last 6 months. All patients were born, lived, and worked in a narrow region in Campania that is under active monitoring because of high rates of environmental pollution. CONCLUSIONS: Known mechanisms of cardiovascular damage generated by environmental pollution are cross linked with described papillary fibroelastomas' etiological cascade. Evidence is suggested for a common origin. These results provide intriguing but inconclusive insights into pathophysiological pathways that may link exposure to environmental pollution and development of papillary fibroelastomas.

Blunt trauma as a cause of rib chondro-osteitis: a case study.

Rib chondro-osteitis is rare and usually caused by tuberculosis. A 63-year-old man presented with fever, painful swelling, and a burning sensation in the parasternal right submammary region. He had a history of cardiac interventions: percutaneous transcatheter angioplasty with stenting 1 year prior and coronary artery bypass graft surgery 16 years before; therefore, he was on dual antiplatelet therapy. He sustained blunt chest trauma 5 months before admission. A chest wall abscess was suspected and fine needle aspiration of the lesion revealed the presence of purulent fluid. Culture results were positive for Staphylococcus aureus and intravenous antibiotic therapy was started. Computed tomography showed a lesion involving the sternal, chondral, and proximal costal portions of the fourth, fifth, and sixth anterior costal arches. The patient was diagnosed with costal chondo-osteitis following blunt trauma. Following aggressive surgical debridement, the wound was managed with topical negative pressure therapy (constant -125 mm Hg setting with daily dressing changes). After 15 days, culture results were negative, the wound bed contained healthy granulation tissue, and the defect was surgically closed using a myocutaneous flap. No recurrence or complications have been observed during the 2-year follow-up. This is the first reported case of pyogenic, posttraumatic, costal chondro-osteitis secondary to a blunt trauma of the chest wall.

Efficacy and Safety of Low-Dose Cyclosporine with Everolimus and Steroids in de novo Heart Transplant Patients: A Multicentre, Randomized Trial.

A six-month, multicenter, randomized, open-label study was undertaken to determine whether renal function is improved using reduced-exposure cyclosporine (CsA) versus standard-exposure CsA in 199 de novo heart transplant patients receiving everolimus and steroids ± induction therapy. Mean C(2) levels were at the low end of the target range in standard-exposure patients (n = 100) and exceeded target range in reduced-exposure patients (n = 99) throughout the study. Mean serum creatinine at Month 6 (the primary endpoint) was 141.0 ± 53.1 µmol/L in standard-exposure patients versus 130.1 ± 53.7 µmol/L in reduced-exposure patients (P = 0.093). The incidence of biopsy-proven acute rejection ≥3A at Month 6 was 21.0% (21/100) in the standard-exposure group and 16.2% (16/99) in the reduced-exposure group (n.s.). Adverse events and infections were similar between treatment groups. Thus, everolimus with reduced-exposure CsA resulted in comparable efficacy compared to standard-exposure CsA. No renal function benefits were demonstrated; that is possibly related to poor adherence to reduced CsA exposure.

Role of vacuum in methicillin-resistant deep sternal wound infection.

Between January 2002 and January 2009, 39 patients with post-cardiotomy staphylococcal deep sternal wound infection were treated primarily by a vacuum-assisted closure method (group A). Results were compared with those of 30 patients with staphylococcal deep sternal wound infection who received closed mediastinal irrigation with antibiotics (group B). The prevalence of methicillin-resistance was similarly high in both groups (64.1% in A, 56.7% in B). One group B patient died during treatment. The median healing time was significantly shorter at 13 days in group A (mean, 13.5 +/- 3.2 days) compared to 18 days (mean, 21.2 +/- 16.4 days) in group B. Deep sternal wound infection did not recur after vacuum treatment, while 7 (24%) patients in group B suffered a recurrence. Hospital stay was significantly shorter in group A (median, 30.5 days; mean, 32.2 +/- 11.3 days vs. median, 45 days; mean, 49.2 +/- 19.3 days). The significantly shorter healing time with vacuum-assisted closure was confirmed in both methicillin-sensitive (12 vs. 17 days) and methicillin-resistant infections (14 vs. 21 days). Hospital stay remained significantly shorter in group A (35 vs. 46 days) when only methicillin-resistant deep sternal wound infection was considered.

LOWERing the INtensity of oral anticoaGulant Therapy in patients with bileaflet mechanical aortic valve replacement: results from the "LOWERING-IT" Trial.

BACKGROUND: Moderate anticoagulation after mechanical heart valve replacement has been proposed to reduce the risk of bleeding related to lifelong anticoagulation. However, the efficacy of such reduced antithrombotic regimens is still unknown. The present prospective open-label, single-center, randomized controlled trial aimed to evaluate the safety and feasibility of reduced oral anticoagulation after isolated mechanical aortic valve replacement. METHODS: Low-risk patients undergoing bileaflet mechanical aortic valve replacement were randomized to a low International normalized ratio (INR) target (1.5-2.5; LOW-INR group) or to the standard currently recommended INR (2.0-3.0; CONVENTIONAL-INR group) through daily coumarine oral therapy. No aspirin was added. Median follow-up was 5.6 years. The primary outcome was assessment of noninferiority of the low over the standard anticoagulation regimen on thromboembolic events. Secondary end point was the superiority of the reduced INR target strategy on bleeding events. RESULTS: We analyzed 396 patients (197 in the LOW-INR group and 199 in the CONVENTIONAL-INR group). The mean of INR was 1.94 +/- 0.21 and 2.61 +/- 0.25 in the LOW-INR and CONVENTIONAL-INR groups, respectively (P < .001). One versus three thromboembolic events occurred in the LOW-INR and CONVENTIONAL-INR, respectively, meeting the noninferiority criterion (P = .62). Total hemorrhagic events occurred in 6 patients in the LOW-INR group and in 16 patients in the CONVENTIONAL-INR group (P = .04). CONCLUSIONS: LOWERING-IT trial established that the proposed LOW-INR target is safe and feasible in low-risk patients after bileaflet aortic mechanical valve replacement. It results in similar thrombotic events and in a significant reduction of bleeding occurrence when compared to the conventional anticoagulation regimen.

Dynamic finite element analysis of the aortic root from MRI-derived parameters.

An understanding of aortic root biomechanics is pivotal for the optimisation of surgical procedures aimed at restoring normal root function in pathological subjects. For this purpose, computational models can provide important information, as long as they realistically capture the main anatomical and functional features of the aortic root. Here we present a novel and realistic finite element (FE) model of the physiological aortic root, which simulates its function during the entire cardiac cycle. Its geometry is based on magnetic resonance imaging (MRI) data obtained from 10 healthy subjects and accounts for the geometrical differences between the leaflet-sinus units. Morphological realism is combined with the modelling of the leaflets' non-linear and anisotropic mechanical response, in conjunction with dynamic boundary conditions. The results show that anatomical differences between leaflet-sinus units cause differences in stress and strain patterns. These are notably higher for the leaflets and smaller for the sinuses. For the maximum transvalvular pressure value, maximum principal stresses on the leaflets are equal to 759, 613 and 603 kPa on the non-coronary, right and left leaflet, respectively. For the maximum aortic pressure, average maximum principal stresses values are equal to 118, 112 and 111 kPa on the right, non-coronary and left sinus, respectively. Although liable of further improvements, the model seems to reliably reproduce the behaviour of the real aortic root: the model's leaflet stretches, leaflet coaptation lengths and commissure motions, as well as the timings of aortic leaflet closures and openings, all matched with the experimental findings reported in the literature.