Prognostic value of SARS-CoV-2 on patients undergoing cardiac surgery.

OBJECTIVE: To analyze Italian Cardiac Surgery experience during the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) identifying risk factors for overall mortality according to coronavirus disease 2019 (COVID-19) status. METHODS: From February 20 to May 31, 2020, 1354 consecutive adult patients underwent cardiac surgery at 22 Italian Centers; 589 (43.5%), patients came from the red zone. Based on COVID-19 status, 1306 (96.5%) were negative to SARS-CoV-2 (COVID-N), and 48 (3.5%) were positive to SARS-CoV-2 (COVID-P); among the COVID-P 11 (22.9%) and 37 (77.1%) become positive, before and after surgery, respectively. Surgical procedures were as follows: 396 (29.2%) isolated coronary artery bypass grafting (CABG), 714 (52.7%) isolated non-CABG procedures, 207 (15.3%) two associate procedures, and three or more procedures in 37 (2.7%). Heart failure was significantly predominant in group COVID-N (10.4% vs. 2.5%, p = .01). RESULTS: Overall in-hospital mortality was 1.6% (22 cases), being significantly higher in COVID-P group (10 cases, 20.8% vs. 12, 0.9%, p < .001). Multivariable analysis identified COVID-P condition as a predictor of in-hospital mortality together with emergency status. In the COVID-P subgroup, the multivariable analysis identified increasing age and low oxygen saturation at admission as risk factors for in-hospital mortality. CONCLUSION: As expected, SARS-CoV-2 infection, either before or soon after cardiac surgery significantly increases in-hospital mortality. Moreover, among COVID-19-positive patients, older age and poor oxygenation upon admission seem to be associated with worse outcomes.

Midterm outcomes of transaortic and transapical TAVI in patients with unsuitable vascular anatomy for femoral access: A propensity score inverse probability weight study.

AIMS: Transaortic (TAo) and transapical (TA) implantation can be used in transcatheter aortic valve implantation (TAVI) when the transfemoral (TF) approach is precluded. We compare the safety and efficacy of these alternative techniques. METHODS: From October 2007 to February 2016, TAo and TA patients' data were collected. Propensity score inverse probability of treatment weight (IPTW) method was employed to minimize the impact of no-randomization bias. RESULTS: From our single-center non-TF-TAVI registry, 282 patients were included: 235 (83.3%) underwent TAo and 47 (16.7%) TA. Differences in baseline characteristics were statistically significant in age, sex, risk profile according to logistic-EuroSCORE, and previous cardiac surgery. No difference in hospital morbidity and mortality, but lower stroke-rate in TAo (1.27% vs. 8.5% p < .01) was observed. This was confirmed at logistic regression after IPTW adjustment (odds ratio [OR]: 0.16, 95% CI 0.03-0.71, p = .01), together with reduced risk of the paravalvular leak (PVL) (OR: 0.14, 95% confidence interval [CI]: 0.02-0.81, p = .02). Kaplan-Meier estimates did not demonstrate differences in long-term mortality among access routes (logrank test p = .13). At the IPTW-Cox regression model, long-term mortality was related to New York Heart Association III-IV (hazard ratio [HR]: 2.92, 95% CI: 1.15-7.40, p = .026), chronic renal failure (HR: 3.25; 95% CI: 1.02-10.32 p = .046), previous transient ischemic attack/stroke (HR: 2.29, 95% CI: 1.25-4.20 p = .007). Sapien-3 device resulted to be a protective factor, reducing long-term mortality (HR: 0.18, 95% CI 0.04- 0.90 p = .03). CONCLUSIONS: TAo is safe and feasible in case of contraindication to femoral approach demonstrating comparable midterm outcomes to TA, thus representing a central access alternative, to increase the overall safety of high-risk TAVI procedures.

The best approach for functional tricuspid regurgitation: A network meta-analysis.

OBJECTIVE: For many years, functional tricuspid regurgitation (FTR) was considered negligible after treatment of left-sided heart valve surgery. The aim of the present network meta-analysis is to summarize the results of four approaches to establish the possible gold standard. METHODS: A systematic search was performed to identify all publications reporting the outcomes of four approaches for FTR, not tricuspid annuloplasty (no TA), suture annuloplasty (SA), flexible (FRA), rigid rings (RRA). All studies reporting at least one the four endpoints (early and late mortality, early and late moderate or more TFR) were included in a Bayesian network meta-analysis. RESULTS: There were 31 included studies with 9663 patients. Aggregate early mortality was 5.3% no TA, 7.2% SA, 6.6% FRA, and 6.4% RRA; early TR moderate-or-more was 9.6%, 4.8%, 4.6%, and 3.8%; late mortality was 22.5%, 18.2%, 11.9%, and 11.9%; late TR moderate-or-more was 27.9%, 18.3%, 14.3%, and 6.4%. Rigid or semirigid ring annuloplasty was the most effective approach for decreasing the risk of late moderate or more FTR (-85% vs. no TA; -64% vs. SA; -32% vs. FRA). Concerning late mortality, no significant differences were found among different surgical approaches; however, flexible or rigid rings reduced significantly the risk of late mortality (78% and 47%, respectively) compared with not performing TA mortality. No differences were found for early outcomes. CONCLUSIONS: Ring annuloplasty seems to offer better late outcomes compare to either suture annuloplasty or not performing TA. In particular rigid or semirigid rings provide more stable FTR across time.

Clinical Course of COVID-19 Infection in Patients Urgently Operated of Cardiac Surgical Procedures.

OBJECTIVE: The aim of this study was to describe the clinical course of a consecutive series of patients operated of urgent cardiac surgery during COVID-19 outbreak. BACKGROUND: In Italy, COVID outbreak has mostly occurred in the metropolitan area of Milan, and in the surrounding region of Lombardy, and previously "conventional" hospitals were converted into COVID spokes to increase ICU beds availability, and to allow only urgent CS procedures. METHODS: Among urgent CS patients (left main stenosis with unstable angina, acute endocarditis, valvular regurgitation with impending heart failure), 10 patients (mean age = 57 ± 9 years), despite a negative admission triage, developed COVID-pneumonia postoperatively, at a median of 7 days after CS. RESULTS: Patients showed typical lymphopenia, higher prothrombotic profile, and higher markers of inflammation (ferritin and interleukin-6 values). At the zenith of pulmonary distress, patients presented with severe hypoxia (median PaO2/FIO2 ratio = 116), requiring advanced noninvasive ventilation (Venturi mask and continuous positive airway pressure) in the majority of cases. All patients were treated with hydroxychloroquine, azithromycin, and low-molecular-weight heparin at anticoagulant dose. Overall in-hospital mortality was 10% (1/10), peaking 25% in patients who developed COVID pneumonia immediately after CS. The remaining patients, with late infection, were all discharged home without oxygen support, at a median of 25 days after symptom onset. CONCLUSIONS: As postoperative mortality in case of COVID pneumonia is not negligible, meticulous rules (precise triage, safe hospital path, high level of protection for health-care teams, prompt diagnosis of suspicious symptoms) should be strictly followed in patients undergoing CS during COVID pandemic. The role of therapies alternative to CS should be further assessed.

Infective endocarditis and neurologic events: indications and timing for surgical interventions.

A therapeutic dilemma arises when infective endocarditis (IE) is complicated by a neurologic event. Postponement of surgery up to 4 weeks is recommended by the guidelines, however, this negatively impacts outcomes in many patients with an urgent indication for surgery due to uncontrolled infection, disease progression, or haemodynamic deterioration. The current literature is ambiguous regarding the safety of cardiopulmonary bypass in patients with recent neurologic injury. Nevertheless, most publications demonstrate a lower risk for secondary haemorrhagic conversion of uncomplicated ischaemic lesions than the risk for recurrent embolism under antibiotic treatment. Here, we discuss the current literature regarding neurologic stroke complicating IE with an indication for surgery.

Right ventricular assessment can improve prognostic value of Euroscore II.

BACKGROUND: The aim of this multicenter prospective study was to evaluate the prognostic weight of preoperative right ventricular assessment on early mortality in cardiac surgery. METHODS: This is a multicenter prospective observational study performed by the Italian Group of Research for Outcome in Cardiac Surgery (GIROC) including 11 centers. From October 2017 to March 2019, out of 923 patients undergoing cardiac surgery, 28 patients with some missing data were excluded and 895 patients were enrolled in the study right ventricular dilatation was defined as a basal end-diastolic diameter >42 mm. The right ventricle (RV) function was assessed using the combination of three parameters: fractional area changing (FAC), tricuspid annular plane systolic excursion (TAPSE), and S'-wave using tissue Doppler imaging (TDI-S'); RV dysfunction was defined as the presence of at least two of the following cutoffs: FAC <35%, TAPSE <17 mm, and TDI S' <9.5 mm RESULTS: Among the entire cohort, 624 (70%) showed normal RV, 92 (10%) isolated RV dilatation, 154 (17%) isolated RV dysfunction, and 25 (3%) both RV dilatation and dysfunction. Non-surviving patients showed a significantly higher rate of RV alteration at multivariable analysis, RV status was found to be an independent predictor for higher in-hospital mortality beside Euroscore II. CONCLUSIONS: This prospective multicenter observation study shows the importance to assess RV preoperatively and to include both RV function and dimension in a risk score model such as Euroscore II to implement its predictivity, since PH cannot always mirror the status of the right ventricle.

BDNFVal66met polymorphism: a potential bridge between depression and thrombosis.

AIMS: Epidemiological studies strongly suggest a link between stress, depression, and cardiovascular diseases (CVDs); the mechanistic correlation, however, is poorly understood. A single-nucleotide polymorphism in the BDNF gene (BDNFVal66Met), associated with depression and anxiety, has been proposed as a genetic risk factor for CVD. Using a knock-in mouse carrying the BDNFVal66Met human polymorphism, which phenocopies psychiatric-related symptoms found in humans, we investigated the impact of this SNP on thrombosis. METHODS AND RESULTS: BDNFMet/Met mice displayed a depressive-like phenotype concomitantly with hypercoagulable state and platelet hyperreactivity. Proteomic analysis of aorta secretome from BDNFMet/Met and wild-type (WT) mice showed differential expression of proteins involved in the coagulation and inflammatory cascades. The BDNF Met allele predisposed to carotid artery thrombosis FeCl3-induced and to death after collagen/epinephrine injection. Interestingly, transfection with BDNFMet construct induced a prothrombotic/proinflammatory phenotype in WT cells. SIRT1 activation, using resveratrol and/or CAY10591, prevented thrombus formation and restored the physiological levels of coagulation and of platelet markers in BDNFMet/Met mice and/or cells transfected with the Met allele. Conversely, inhibition of SIRT1 by sirtinol and/or by specific siRNA induced the prothrombotic/proinflammatory phenotype in WT mice and cells. Finally, we found that BDNF Met homozygosity is associated with increased risk of acute myocardial infarction (AMI) in humans. CONCLUSION: Activation of platelets, alteration in coagulation pathways, and changes in vessel wall protein expression in BDNFMet/Met mice recapitulate well the features occurring in the anxiety/depression condition. Furthermore, our data suggest that the BDNFVal66Met polymorphism contribute to the individual propensity for arterial thrombosis related to AMI.

ANMCO/SIC/SICI-GISE/SICCH Executive Summary of Consensus Document on Risk Stratification in elderly patients with aortic stenosis before surgery or transcatheter aortic valve replacement.

Aortic stenosis is one of the most frequent valvular diseases in developed countries, and its impact on public health resources and assistance is increasing. A substantial proportion of elderly people with severe aortic stenosis is not eligible to surgery because of the advanced age, frailty, and multiple co-morbidities. Transcatheter aortic valve implantation (TAVI) enables the treatment of very elderly patients at high or prohibitive surgical risk considered ineligible for surgery and with an acceptable life expectancy. However, a significant percentage of patients die or show no improvement in quality of life (QOL) in the follow-up. In the decision-making process, it is important to determine: (i) whether and how much frailty of the patient influences the risk of procedures; (ii) how the QOL and the individual patient's survival are influenced by aortic valve disease or from other associated conditions; and (iii) whether a geriatric specialist intervention to evaluate and correct frailty or other diseases with their potential or already manifest disabilities can improve the outcome of surgery or TAVI. Consequently, in addition to risk stratification with conventional tools, a number of factors including multi-morbidity, disability, frailty, and cognitive function should be considered, in order to assess the expected benefit of both surgery and TAVI. The pre-operative optimization through a multidisciplinary approach with a Heart Team can counteract the multiple damage (cardiac, neurological, muscular, respiratory, and kidney) that can potentially aggravate the reduced physiological reserves characteristic of frailty. The systematic application in clinical practice of multidimensional assessment instruments of frailty and cognitive function in the screening and the adoption of specific care pathways should facilitate this task.

Mitral valve endothelial cells secrete osteoprotegerin during endothelial mesenchymal transition.

AIMS: Mitral valve prolapse (MVP) has a prevalence of 3% in the general population, affecting >176 million people worldwide. Despite this, little is known about the molecular and cellular mechanisms involved in the progression of MVP and surgical intervention is the only available option. In this study we investigated the role of osteoprotegerin (OPG) during endothelial to mesenchymal transition (EndMT) in MVP. METHODS AND RESULTS: VECs and VICs were isolated from posterior mitral valve leaflets of patients undergoing mitral valve repair (n=25). Plasma was collected from 57 subjects (29 controls and 28 MVP patients). Overexpression of OPG during EndMT followed by autocrine effects characterised by reactive oxygen species increment and accelerated migration was documented. In addition, OPG increased VIC proliferation. Finally, OPG plasma levels were significantly higher in MVP patients compared to control subjects and the area under the ROC curve was 0.92. CONCLUSION: EndMT has been recognised as a possible pathological mechanism for MVP. For the first time, we report the involvement of OPG in cellular and molecular changes in MVP isolated cells. In addition, we detected elevated circulating OPG levels in MVP patients when compared to controls, which supports the hypothesis that OPG is involved in MVP development and progression.

Normal human mitral valve proteome: A preliminary investigation by gel-based and gel-free proteomic approaches.

The mitral valve is a highly complex structure which regulates blood flow from the left atrium to the left ventricle (LV) avoiding a significant forward gradient during diastole or regurgitation during systole. The integrity of the mitral valve is also essential for the maintenance of normal LV size, geometry, and function. Significant advances in the comprehension of the biological, functional, and mechanical behavior of the mitral valve have recently been made. However, current knowledge of protein components in the normal human mitral valve is still limited and complicated by the low cellularity of this tissue and the presence of high abundant proteins from the extracellular matrix. We employed here an integrated proteomic approach to analyse the protein composition of the normal human mitral valve and reported confident identification of 422 proteins, some of which have not been previously described in this tissue. In particular, we described the ability of pre-MS separation technique based on liquid-phase IEF and SDS-PAGE to identify the largest number of proteins. We also demonstrated that some of these proteins, e.g. αB-Crystallin, septin-11, four-and-a-half LIM domains protein 1, and dermatopontin, are synthesised by interstitial cells isolated from human mitral valves. These initial results provide a valuable basis for future studies aimed at analysing in depth the mitral valve protein composition and at investigating potential pathogenetic molecular mechanisms. Data are available via ProteomeXchange with identifier PXD004397.

Does EuroSCORE II perform better than its original versions? A multicentre validation study.

AIMS: The European system for cardiac operation risk evaluation (EuroSCORE) is widely used for predicting in-hospital mortality after cardiac surgery. A new score (EuroSCORE II) has been recently developed to update the previously released versions. This study was undertaken to validate EuroSCORE II, to compare its performance with the original EuroSCOREs and to evaluate the effects of the removal of those factors that were included in the score even if they were statistically non-significant. METHODS AND RESULTS: Data on 12,325 consecutive patients who underwent major cardiac surgery in a 6-year period were retrieved from three prospective institutional databases. Discriminatory power was assessed using the c-index and comparison among the scores' performances was performed with Delong, bootstrap, and Venkatraman methods. Calibration was evaluated with calibration curves and associated statistics. The in-hospital mortality rate was 2.2%. The discriminatory power was high and similar in all algorithms (area under the curve 0.82, 95% CI: 0.79-0.84 for additive EuroSCORE; 0.82, 95% CI: 0.79-0.84 for logistic EuroSCORE; 0.82, 95% CI: 0.80-0.85 for EuroSCORE II). The EuroSCORE II had a fair calibration till 30%-predicted values and over-predicted beyond. The removal of non-significant factors from EuroSCORE II did not affect performance, being both the calibration and discrimination comparable. CONCLUSION: This validation study demonstrated that EuroSCORE II is a good predictor of perioperative mortality. It showed an optimal calibration until 30%-predicted mortality. Nonetheless, it does not seem to significantly improve the performance of older versions in the higher tertiles of risk. Moreover, it could be simplified, as the removal from the algorithm of non-significant factors does not alter its performance.

[Total artificial heart: past, present, and future]. / Cuore artificiale totale: passato, presente e futuro.

Every year, approximately 5 out of 1000 patients receive a diagnosis of advanced heart failure, with a prevalence of 1-2% in the adult population. This figure is likely underestimated, considering undiagnosed cases. Despite significant progress in medical therapy for heart failure, mortality rates persist around 20% within the first year, reaching 50-60% at 5 years from the initial diagnosis. For patients with severe end-stage heart failure, the 1-year mortality rate can reach up to 70%. Heart transplantation remains the preferred treatment for terminal stages of the disease; however, the significant challenge lies in the mismatch between available donors and recipients. Given this dilemma, both short-term solutions including extracorporeal membrane oxygenation and long-term options such as left ventricular assist devices have gained prominence. These mechanical circulatory support systems become crucial for patients in critical conditions, temporarily ineligible for heart transplantation, such as those with severe irreversible pulmonary hypertension or acute organ failure. Despite these advancements, a growing number of patients on the waiting list develops severe biventricular dysfunction, precluding the use of a left ventricular assist device as a bridge to transplant. In such cases, a total artificial heart emerges as a viable therapeutic option.

[Choosing a tailored prosthetic valve in cardiac surgery: what is the current role of mechanical prostheses?] / Il ruolo delle protesi valvolari meccaniche oggi. Dalla letteratura alla situazione italiana.

The choice of the mechanical/biological heart valve prosthesis is a topic currently debated in the light of the transcatheter prosthetic models and the results obtained/expected with the new biological valve models. Consequently, it seems that increasingly younger patients would be indicated for an implantation of a biological prosthesis. This is also in order to improve the quality of life of patients who want to avoid oral anticoagulant therapy. On the other hand, the guidelines for the treatment of heart valve disease assign a central role to the use of mechanical valve prostheses, particularly for certain patient subsets and age groups. This means that mechanical prostheses are still widely used worldwide, especially in non-European or North American regions. The cardiac surgery community therefore seems to be very interested in biological prostheses and transcatheter implants and scarcely interested in mechanical prostheses, including possible strategies for self-management of anticoagulant therapy. Recently, the Italian Society of Cardiac Surgery promoted a survey among its members to stimulate interest in the cardiac surgery community. This review article aims to summarize the most current results recorded with the use of mechanical prostheses and possible strategies, especially for the management of oral anticoagulant therapy, which can improve the patient's quality of life.

Mechanical heart valves and oral anticoagulation: a survey of the Italian Society of Cardiac Surgery.

In the latest European guidelines for the management of valvular heart disease, mechanical valve prostheses maintain a strategic role, particularly for certain patient subsets and age groups. Despite the high number of devices implanted in clinical practice, particularly in non-European and North American regions, current scientific literature and debate seem to suggest a limited use of mechanical heart valves. The cardiac surgery community seems to be highly interested in biological and transcatheter valve prostheses but less interested in mechanical heart valves, including possible strategies for self-management of anticoagulation therapy. In this respect, the Italian Society of Cardiac Surgery (SICCH), in particular the Italian Group of Research for Outcome in Cardiac Surgery (GIROC), has promoted a survey among its members to stimulate the interest in this topic and express their opinion on this issue that, due to the prevalence of the affected population and the new treatment options for improving patients' quality of life, should be more appraised and debated in the cardiac surgery community. The recorded results, obtained on the answers to 111 questionnaires, seem to divide the specialists into 'pros' and 'contras' on a useful tool for the entire cardiac surgery community. For this reason, SICCH proposes in conclusion to declare its unified and institutional opinion on this topic.

Comparison of 4 mortality scores for surgical repair of type A aortic dissection: a multicentre external validation.

OBJECTIVES: In the last decades, 4 different scores for the prediction of mortality following surgery for type A acute aortic dissection (TAAD) were proposed. We aimed to validate these scores in a large external multicentre cohort. METHODS: We retrospectively analysed patients who underwent surgery for TAAD between 2000 and 2020. Patients were enrolled from 10 centres from 2 European countries. Outcomes were the early (30-day and/or in-hospital) and 1-year mortality. Discrimination, calibration and observed/expected (O/E) ratio were evaluated. RESULTS: A total of 1895 patients (31.7% females, mean age 63.72 ± 12.8 years) were included in the study. Thirty-day mortality and in-hospital mortality were 21.7% (n = 412) and 22.5% (n = 427) respectively. The German Registry of Acute Aortic Dissection Type A (GERAADA) score shows to have the best discrimination [area under the curve (AUC) 0.671 and 0.672] in predicting as well the early and the 1-year mortality, followed by the International Registry of Acute Aortic Dissection (IRAD) model 1 (AUC 0.658 and 0.672), the Centofanti (AUC 0.645 and 0.66) and the UK aortic score (AUC 0.549 and 0.563). According to Hosmer-Lemeshow and Brier tests, the IRAD model I and GERAADA, respectively, were well calibrated for the early mortality, while the GERAADA and Centofanti for the 1-year mortality. The O/E analysis showed a marked underestimation for patients labelled as low-risk for UK aortic score and IRAD model I for both outcomes. CONCLUSIONS: The GERAADA score showed the best performance in comparison with other scores. However, none of them achieved together a fair discrimination and a good calibration for predicting either the early or the 1-year mortality.

Transcriptional regulation of the human FPR2/ALX gene: evidence of a heritable genetic variant that impairs promoter activity.

Lipoxin (LX) A(4,) a main endogenous stop-signal of inflammation, activates the G-protein-coupled receptor FPR2/ALX, which triggers potent anti-inflammatory signaling in vivo. Thus, the regulation of FPR2/ALX expression may have pathophysiological and therapeutic relevance. Here, we mapped a nucleotide sequence with strong FPR2/ALX promoter activity. Chromatin immunoprecipitation revealed specificity protein 1 (Sp1) binding to the core promoter. Site-directed mutagenesis of the Sp1 cis-acting element and Sp1 overexpression established that this transcription factor is key for maximal promoter activity, which is instead suppressed by DNA methylation. LXA(4) enhanced FPR2/ALX promoter activity (+74%) and mRNA expression (+87.5%) in MDA-MB231 cells. A single nucleotide mutation (A/G) was detected in the core promoter of one subject with history of cardiovascular disease and of his two daughters. This mutation reduced by ∼35-90% the promoter activity in vitro. Moreover, neutrophils from individuals carrying the A/G variant displayed ∼10- and 3-fold reduction in FPR2/ALX mRNA and protein, respectively, compared with cells from their relatives or healthy volunteers expressing the wild-type allele. These results uncover FPR2/ALX transcriptional regulation and provide the first evidence of mutations that affect FPR2/ALX transcription, thus opening new opportunities for the understanding of the LXA(4)-FPR2/ALX axis in human disease.

Direct anticoagulant drugs to overcome limitations of vitamin K antagonists. A critical appraisal of data in atrial fibrillation patients.

INTRODUCTION: The usefulness of anticoagulation in patients with atrial fibrillation (AF) is well known. However, the inherent limitations of vitamin K antagonists (VKAs) have made the development of new oral anticoagulants necessary. Drugs directed against thrombin or the factor Xa are currently available. AREAS COVERED: These molecules, being administered at fixed doses and not requiring laboratory monitoring, overcome one crucial problem associated with the use of VKAs. However, data about the bleeding risk related to the use of these molecules should be further analyzed. EXPERT OPINION: The efficacy of direct anticoagulants (DACs) in AF-related stroke prevention has been considered the primary outcome in all Phase III published trials. On the other hand, the reduction of the bleeding risk is an important goal achieved by the DACs as compared with VKAs. Besides data deriving from randomized trials, when talking about new drugs, the need of evidences from the 'everyday clinical practice' are often requested. The aim of this literature revision is to report and analyze data from specific subgroups about which little is known. In particular, information about the use of DACs in oncologic patients, in patients receiving concomitant antiplatelet drugs and in the perioperative period is currently lacking. The parallel evaluation of all these data may lead to the identification of clinical and demographical criteria to choose when to switch to DACs.

Biology of mitral valve prolapse: from general mechanisms to advanced molecular patterns-a narrative review.

Mitral valve prolapse (MVP) represents the most frequent cause of primary mitral regurgitation. For several years, biological mechanisms underlying this condition attracted the attention of investigators, trying to identify the pathways responsible for such a peculiar condition. In the last ten years, cardiovascular research has moved from general biological mechanisms to altered molecular pathways activation. Overexpression of TGF-ß signaling, for instance, was shown to play a key role in MVP, while angiotensin-II receptor blockade was found to limit MVP progression by acting on the same signaling pathway. Concerning extracellular matrix organization, the increased valvular interstitial cells density and dysregulated production of catalytic enzymes (matrix metalloproteinases above all) altering the homeostasis between collagen, elastin and proteoglycan components, have been shown to possibly provide a mechanistic basis contributing to the myxomatous MVP phenotype. Moreover, it has been observed that high levels of osteoprotegerin may contribute to the pathogenesis of MVP by increasing collagen deposition in degenerated mitral leaflets. Although MVP is believed to represent the result of multiple genetic pathways alterations, it is important to distinguish between syndromic and non-syndromic conditions. In the first case, such as in Marfan syndrome, the role of specific genes has been clearly identified, while in the latter a progressively increasing number of genetic loci have been thoroughly investigated. Moreover, genomics is gaining more interest as potential disease-causing genes and loci possibly associated with MVP progression and severity have been identified. Animal models could be of help in better understanding the molecular basis of MVP, possibly providing sufficient information to tackle specific mechanisms aimed at slowing down MVP progression, therefore developing non-surgical therapies impacting on the natural history of this condition. Although continuous progress has been made in this field, further translational studies are advocated to improve our knowledge of biological mechanisms underlying MVP development and progression.