Impossibility Results on Stability of Phylogenetic Consensus Methods.

We answer two questions raised by Bryant, Francis, and Steel in their work on consensus methods in phylogenetics. Consensus methods apply to every practical instance where it is desired to aggregate a set of given phylogenetic trees (say, gene evolution trees) into a resulting, "consensus" tree (say, a species tree). Various stability criteria have been explored in this context, seeking to model desirable consistency properties of consensus methods as the experimental data are updated (e.g., more taxa, or more trees, are mapped). However, such stability conditions can be incompatible with some basic regularity properties that are widely accepted to be essential in any meaningful consensus method. Here, we prove that such an incompatibility does arise in the case of extension stability on binary trees and in the case of associative stability. Our methods combine general theoretical considerations with the use of computer programs tailored to the given stability requirements. [Associative stability; consensus; extension stability; phylogeny.].

Incidence of perioperative stroke in clampless aortic anastomosis during off-pump coronary artery bypass grafting.

This study aimed to assess if clampless off-pump coronary artery bypass grafting (OPCAB) decreases the incidence of perioperative stroke (POS) rate and in-hospital mortality. The secondary aim was to evaluate 12-year rates of overall mortality. Between January 2003 to December 2015, data of 645 consecutive patients undergoing isolated CABG were retrospectively collected. 363 underwent aortic no-touch OPCAB (No-touch group) and 282 underwent OPCAB with the Heartstring device (HS group). In-hospital mortality and perioperative stroke rate as primary endpoint, as well as long-term follow-up outcome were analysed. In-hospital mortality was lower into No-touch group compared with HS group but without significant statistical difference (1.7 vs. 3.2%, p = 0.19, respectively); the rate of postoperative stroke was higher in No-touch group compared with HS group, although this difference did not reach statistically significance. Delirium was reported with higher presentation rate in HS group (3.9 vs. 0.8%, p = 0.01). Blood transfusions rate was higher in HS subjects (23.4 vs. 16.1%, p = 0.01). Intubation time, ICU, and hospital length of stay were increased in the HS group (p = 0.008, p = 0.001 and p = 0.003, respectively). Over a 12-year follow-up period, survival probabilities at 1, 5, and 10 years were 93.6 ± 1.3 vs. 93.2 ± 1.5, 80.4 ± 2.6 vs. 80.3 ± 2.2, and 57.9 ± 5 vs. 58.4 ± 3.8% in the No-touch and HS group, respectively (p = 0.97). In this retrospective study, clampless off-pump CABG lowers perioperative stroke rate whose incidence is, however, not inferior compared with No-touch technique, and no statistically significance was detected. Delirium has a higher presentation rate in clampless off-pump CABG.

Implantation of the Jarvik 2000® left ventricular assist device using the miniaturized extracorporeal circulation system - a case report.

Myocardial failure is generally considered to be a progressive, irreversible medical condition with characteristic ventricular enlargement, spatial alteration of the heart chambers, diminished cardiac inotropy and resultant dysfunctional, mechanically inefficient heart.The Jarvik 2000®, similar to the mechanical pump, is an electrically powered, axial-flow left ventricular assist device (LVAD) designed to enhance the function of the chronically failing heart and, consequently, normalize the cardiac output for a long period of time.We report the case of 70-year-old man with congestive dilated cardiomyopathy and bioprosthetic mitral valve who underwent surgical implantation of the Jarvik 2000® LVAD, using the miniaturized extracorporeal circulation (MECC) system.The LVAD was implanted through a left thoracotomy and the MECC system was used to avoid intraoperative spontaneous hemodynamic instability and/or malignant ventricular arrhythmia. The circulatory support with the MECC system was optimal and no complication in terms of hemodynamic instability and perioperative bleeding was recorded. The MECC system obliterated the adverse effects associated with conventional extracorporeal circulation, which are often fatal in critically-ill patients.

A rare case of ALCAPA and rheumatic mitral valve regurgitation in an adult patient.

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital coronary artery defect leading to sudden cardiac death. Diagnosis is made after the onset of symptoms, mainly in the pediatric population. We describe an uncommon presentation of ALCAPA and rheumatic mitral valve regurgitation, diagnosed by a coronary 64-CT scan performed before a planned mitral valve repair operation.

Type 2 diabetes mellitus is associated with faster degeneration of bioprosthetic valve: results from a propensity score-matched Italian multicenter study.

BACKGROUND: The present study was aimed at determining the impact of type 2 diabetes mellitus (DM) on postoperative bioprosthetic structural valve degeneration. METHODS AND RESULTS: Twelve Italian centers participated in the study. Patient data refer to bioprosthetic implantations performed from November 1988 to December 2009, which resulted in 6184 patients (mean age 71.3±5.4 years, 60.1% male) being enrolled. Of these patients, 1731 (27.9%) had type 2 DM. The propensity score-matching algorithm successfully matched 1113 patients with type 2 DM with the same number of no-DM patients. The postmatching standard differences were less than 0.1 for each of the covariates, and 64.2% of DM patients were matched. The early (30 days) mortality rate was 7.8% (n=87) versus 2.9% (n=33) in patients with or without type 2 DM (P<0.001), respectively. Seven-year freedom from valve deterioration was significantly lower in patients with DM (73.2% [95% confidence interval, 61.6-85.5] versus 95.4% [95% confidence interval, 83.9-100], P<0.001). In Cox regression models with robust SEs that accounted for the clustering of matched pairs, DM was the strongest predictor of structural valve degeneration (hazard ratio 2.39 [95% confidence interval 2.28-3.52]). When we allowed for interaction between type 2 DM and other key risk factors, DM remained a significant predictor beyond any potentially associated variable. CONCLUSIONS: Patients with type 2 DM undergoing bioprosthetic valve implantation are at high risk of early and long-term mortality, as well as of structural valve degeneration.

Simultaneous management of renal carcinoma with caval vein thrombosis and double coronary artery disease.

INTRODUCTION: Recent advances in surgical and anesthesiology techniques allow simultaneous thoracic and abdominal operations to be performed for severe heart disease and benignant or malignant abdominal diseases. CASE REPORT: The simultaneous surgical management in a 75-year-old patient suffering from severe double coronary artery disease and a renal cell carcinoma with extended intravascular growth into the inferior vena cava is reported. CONCLUSION: The postoperative course was uneventful. Simultaneous surgery proved to be beneficial and safe, showing optimal results in our patient.

Inflammatory activation during coronary artery surgery and its dose-dependent modulation by statin/ACE-inhibitor combination.

BACKGROUND: On-pump coronary artery bypass graft (CABG) surgery triggers an inflammatory response (IR) which may impair revascularization. The study aimed at (1) characterizing the temporal profile of the IR by assaying appropriate markers in both systemic and coronary blood, and (2) determining whether (and which doses of) cardiovascular drugs known to have antiinflammatory properties, namely statins and ACE-inhibitors (ACEI), inhibit the response. METHODS AND RESULTS: Patients scheduled for CABG (n=22) were randomized to statin/ACEI combination treatment at standard doses (STD, ramipril 2.5/simvastatin 20 mg, or atorvastatin 10 mg), or at high doses (HiDo, ramipril 10 mg, or enalapril 20 mg/simvastatin 80 mg, or atorvastatin 40 mg). Plasma levels of interleukin 6, tumor necrosis factor alpha, E-selectin, von Willebrand factor (vWF), and sVCAM-1 were serially assayed (ELISA) before, during, and after CABG. Blood was drawn from an artery, a systemic vein, and the coronary sinus. Myocardial perfusion scans were obtained before and 2 months after surgery in 19 out of 22 subjects. In the STD group both IL-6 and TNF displayed striking increases which were similar at all sites and peaked 10 to 60 minutes after aortic declamping. Such increases were drastically attenuated in the HiDo group. Instead, only modest increases in venous E-selectin, vWF, and sVCAM-1 were observed. Scintigraphic ischemia scores were entirely normalized after versus before CABG in the HiDo but not in the STD treatment group. CONCLUSIONS: On-pump CABG surgery is associated with an intense systemic inflammatory response, which can be almost completely prevented by early treatment with high (but not standard) doses of ACE-inhibitors and statins.

Postinfarction left ventricular free wall rupture: a 17-year single-centre experience.

OBJECTIVES: Left ventricular free wall rupture (LVFWR) is a catastrophic complication following acute myocardial infarction with an estimated incidence of 0.2-7.6% and mortality can be as high as 60%. This study aimed to identify the risk factors for morbidity and mortality in patients affected by LVFWR. METHODS: This is a retrospective study of 35 patients who underwent surgery for LVFWR between January 2000 and December 2016 at our institution. RESULTS: The mean age of patients was 68.3 years. The in-hospital survival was 65.7% (n = 23), and 13% of survived patients presented with cardiac arrest. The following characteristics were associated with in-hospital mortality at univariable analysis: pre-existing hypertension (P = 0.02), need for inotropes (P = 0.02) and cardiac arrest (P < 0.0001) at presentation, cardiopulmonary resuscitation (P = 0.004), preoperative extracorporeal membrane oxygenation (P = 0.004), technique of LVFWR repair (P = 0.013), operation on extracorporeal membrane oxygenation (P = 0.005) and postoperative extracorporeal membrane oxygenation (P = 0.001). In the multivariable analysis, cardiac arrest at presentation was an independent predictor of in-hospital mortality (odds ratio 11.7, 95% confidence interval 2.352-59.063; P = 0.003). The overall mean postoperative follow-up was 8.3 ± 1.3 years. Overall survival rates at 5 and 10 years were 53.2 ± 8.6% and 49.1 ± 8.9%, respectively. Among the survivors, only 6 (26.1%) patients died during follow-up with a 5-year and 10-year overall survival rate of 80.9 ± 8.7% and 74.7 ± 10%, respectively. CONCLUSIONS: These data suggest a trend towards long-term benefit in patients surviving high-risk surgery for LVFWR repair. Considering the high lethality of LVFWR, the urgency and complexity of the primary surgical intervention early diagnosis and prompt surgery play a key role in the management of this complication.

Unusually large left atrial myxoma causing mitral valve occlusion and hiding a severe mitral regurgitation: a case report.

We report a case of a 68-year-old woman with a large left atrial myxoma occluding the mitral valve. The tumor was diagnosed by preoperative echocardiogram. During the operation and after the myxoma resection, a severe mitral valve regurgitation, which was not observed during the preoperative echocardiogram, was noticed. Mitral valve defect was corrected by an annuloplasty ring, and the patient had an uneventful recovery. Careful evaluation of the mitral valve during a myxoma resection operation is recommended.

Post-valvular surgery multi-vessel coronary artery spasm - A literature review.

Coronary artery spasm (CAS) refers to the spontaneous or stimuli-induced transient, often localized and intense subtotal or total constriction/occlusion of the epicardial coronary artery, usually concomitant with angina pectoris with associated elevation of the ST segment on electrocardiogram (ECG). In this article, we present a literature review on post-valvular surgery CAS and report the clinical case of a 77 year-old man who experienced severe early post-aortic surgery chest pain and hemodynamic instability. Emergent coronary angiography revealed severe occlusion of multiple branches of both coronary arteries. The CAS was alleviated with intracoronary infusion of nitroglycerin.

Early vascular complications after percutaneous cannulation for extracorporeal membrane oxygenation for cardiac assist.

BACKGROUND: Extracorporeal membrane oxygenation (VA ECMO) demonstrated an advantage in survival and neurological outcome in patients with cardiogenic shock and, in selected population, in victims of refractory cardiac arrest. The incidence of vascular complications ranges in recent series from 10 to 70% including both early and late complications. The aim of the present study was to determine the incidence of early vascular complications and the effectiveness of the prevention of limb ischemia by the insertion of a catheter for distal perfusion. METHODS: Data from our registry of 100 patients treated with VA ECMO implanted via percutaneous femoral approach for cardiogenic shock or refractory cardiac arrest were analyzed. If the leg perfusion was inadequate, an additional 7-9 Fr percutaneous catheter distal to the ECMO arterial cannula was placed into the femoral artery to prevent limb ischemia. RESULTS: Thirty-five patients had early vascular complications. Thirty patients with early ischemia were cannulated with a small reperfusion cannula to obtain antegrade perfusion of the limb. Twenty-six had an effective reperfusion. Seven patients developed a compartment syndrome of the leg requiring urgent fasciotomy that led to clinical improvement and recovery in five, while the other two patients progressed to irreversible ischemia requiring amputation of the limb. CONCLUSION: The majority of ischemic episodes were resolved with the insertion of a distal perfusion catheter. We did not observe any mortal vascular complication, nor any of the observed complications was related to increased mortality.

Dual left anterior descending coronary artery from right aortic sinus: report of a case of recurrent unstable angina after CABG.

Anomalies of the left coronary artery are very rare, with an incidence range between .3% and 1.64%. The diagnosis is generally incidental during coronary angiogram, coronary artery bypass operation, or autopsy. However, sometimes this anomaly is not recognized during CABG operation and can be responsible for the recurrence of angina after CABG operation and even compromise the outcome. We presented a case in which the dual left anterior coronary artery from the right aortic sinus occasionally was shown in a coronary angiogram after CABG operation; the angiogram was performed because of the recurrence of angina.

Quadricuspid aortic valve as a cause of severe aortic regurgitation.

Quadricuspid aortic valves (QAVs) constitute a rare congenital malformation, with an incidence ranging from 0.008 to 0.048%. We report a case of severe aortic regurgitation associated with a QAV, which was diagnosed intraoperatively using transesophageal echocardiography. Since the first case described in 1862, 186 QAVs have been reported. In most cases, QAVs are associated with valve regurgitation, with a concurrent stenosis in some patients, while only a small number of QAVs are functionally normal. Once the diagnosis has been made, echocardiographic follow-up is recommended, as progression to severe valve regurgitation is common. Antibiotic prophylaxis is advisable for dental, and "dirty" surgical procedures, to minimize the risk of infective endocarditis.

The early outcome in patients undergoing off-pump coronary artery bypass grafting: our experience.

BACKGROUND: Many studies confirm that beating heart surgery is an alternative to on-pump myocardial revascularization. However, the clinical conditions of patients are currently considered as a major landmark in the indication for beating heart surgery. This retrospective non-randomized study was carried out to evaluate the efficacy and the advantages of this surgical technique when anatomical criteria are used to choose the surgical strategy. METHODS: From February to December 2003, 222 consecutive patients underwent isolated myocardial revascularization: 76 (34%) with an off-pump coronary artery bypass (OPCAB) and 146 (66%) with an on-pump coronary artery bypass (ONCAB) procedure. Selection for surgical treatment was based on coronary anatomy. All patients were stratified for mortality risk class according to the EuroSCORE system. Operative and postoperative data were analyzed. RESULTS: Morbidity and mortality did not differ significantly between the two groups but the release of creatine kinase-MB fraction was significantly higher in the ONCAB group (48.7 +/- 55.3 vs 20.8 +/- 16.6 U/ml, p < 0.001). Patients at high surgical risk were dealt with a more complicated clinical outcome; logistic regression analysis showed that this class was an independent risk factor for postoperative complications in both groups. CONCLUSIONS: We did not find any statistical difference in hospital mortality and morbidity either using ONCAB or OPCAB; however a lower release of creatine kinase-MB in beating heart revascularization group suggests that OPCAB reduces myocardial injury and preserves cardiac function when anatomical criteria are considered for patient selection.

L-arginine effects on myocardial stress in cardiac surgery: preliminary results.

BACKGROUND: L-arginine in addition to cardioplegia stimulates the release of nitric oxide and increases coronary blood flow, decreasing platelet activation and leukocyte adhesion. The aim of our study was to determine the feasibility and the efficacy of the addition of L-arginine to antegrade and retrograde blood cardioplegia in reducing myocardial damage and stress. METHODS: Twenty-eight consecutive patients who underwent coronary artery bypass grafting were randomized to receive 7.5 g of L-arginine in 500 ml of cardioplegic solution. To assess safety of use of L-arginine, hemodynamic evaluation was performed before sternum opening, at sternum closure, and 1 hour after arrival in the intensive care unit to measure cardiac index, systemic and pulmonary vascular resistances, and pulmonary capillary wedge pressure. Moreover, transesophageal echocardiography was performed to assess myocardial contractility. To determine the effects on myocardial stress, blood samples were taken from the retrograde coronary sinus catheter for lactate, interleukin (IL)-2 receptor, IL-6 and tumor necrosis factor (TNF)-alpha levels. Serum samples (preoperatively, 2, 18 and 42 hours after aortic cross-clamping removal) were also analyzed to measure creatine phosphokinase, creatine kinase-MB mass, cardiac troponin T, platelets, and leukocytes. RESULTS: We found statistical differences for IL-2 receptor, IL-6, TNF-alpha, platelets and leukocytes, in favor of the treated group, and decreasing trends in creatine kinase-MB mass and troponin T levels. CONCLUSIONS: The present study shows the positive effects of the addition of L-arginine to cardioplegia. Reduced IL-2 receptor, IL-6 and TNF-alpha indicate a decrease in myocardial stress. Safety of Larginine is related to lower values of systemic vascular resistances and pulmonary capillary wedge pressure observed in group A postoperatively that could improve the patient's outcome in terms of a reduced need for inotropic support. Moreover, the decrease in platelet and leukocyte count in the treated group might express a reduced no-reflow phenomenon and a better reperfusion, limiting endothelial injury from oxygen radical production.

St. Jude Medical Trifecta aortic valve: results from a prospective regional multicentre registry.

BACKGROUND: The Trifecta aortic bioprosthesis (St. Jude Medical, Inc., St. Paul, MN, USA) is a stented pericardial heart valve with excellent preliminary results. Aim of the study was to evaluate its early clinical and hemodynamic performances in a multicenter regional registry. METHODS: Between January 2011 and June 2012, 178 consecutive patients undergoing aortic valve replacement with the Trifecta bioprosthesis were prospectively enrolled at 9 Italian centers. Clinical and echocardiographic data were collectedat discharge, 6-months and at 1-year postoperatively. RESULTS: The average age was 75.4 ± 7.7 years,and 95 (53 %) were men. Indication for valve replacement included stenosis in 123 patients (69 %), mixed lesions in 25 (14 %), and regurgitation in 30 (17 %). Ninety-three (52 %) patients were in NYHA functional class III/ IV. Hospital mortality accounted for 5 (2.8 %) patients. No valve-related perioperative complications were encountered. Median follow-up was 20.5 months (range: 1-34). Early (≤6 months) complications included one thromboembolic event, one major bleeding, and 3 endocarditis (2 explants). Two late (>6 months) thromboembolic events and two endocarditis (1 explant) were registered. No valve thrombosis or structural deterioration were observed after discharge. At 30-months, freedom from all-cause mortality was 87 %, freedom from valve-related mortality 99.4 %, freedom from endocarditis 97.5 %, and freedom from valve explants 98 %. At 1-year, mean gradients ranged from 8 to 16 mmHg, and effective orifice area indexes from 1.0 to 1.2 cm(2)/m(2) for valve sizes from 19 to 27 mm, respectively. No patients had severe prosthesis-patient mismatch. CONCLUSIONS: Trifecta bioprosthesis provided favourable clinical and hemodynamic results over time.

Long-term follow-up of total arterial myocardial revascularization using exclusively pedicle bilateral internal thoracic artery and right gastroepiploic artery.

OBJECTIVE: In order to reduce remote cardiac events associated with graft occlusions, arterial conduits are being increasingly utilized in coronary artery bypass grafting (CABG). While the internal thoracic artery (ITA) is the graft of choice for CABG, it is sometimes difficult or impossible to obtain a complete arterial revascularization only with ITAs in three-vessel diseases. We present our experience with total arterial myocardial revascularization with bilateral internal thoracic artery (BITA) and right gastroepiploic artery (rGEA). METHODS: From April 1994 to January 2004, 174 patients (165 male, mean age 55.9+/-7.4) underwent coronary artery bypass procedure with exclusive use of BITA and rGEA. Left ventricular ejection fraction ranged from 20 to 68% (mean 55.9+/-6.8%). Seven patients (4%) had poor ejection fraction (<0.30), 23 (13, 2%) had acute myocardial infarction, 14 (8%) had left main disease. The mean CPB time was 96.9+/-15.7 min and the mean cross clamping time was 70+/-14.2 min. The mean number of distal anastomoses was 3.3+/-0.5 per patient. RESULTS: Early mortality was 1.7%. The patients were followed for up to 9 years (mean follow-up time 6.3+/-2.6 years). Actuarial freedom from cardiac death (including hospital death) was 97.6%, at 9 years after the operation. Actuarial freedom from angina and cardiac events at 9 years was 79, 5% and 77, 6%, respectively. No perioperative myocardial infarction occurred. None of the patients needed a redo-CABG after leaving the hospital. CONCLUSIONS: This study indicates that the myocardial revascularization in young patients with three-vessel disease using exclusively pedicle BITA and rGEA provides excellent 9-year patient survival and improvement in terms of freedom from return of angina pectoris and freedom from any cardiac-related event. These results encourage the more extensive use of BITA and rGEA in selected patients with three-vessel coronary disease.

Late driveline left ventricular assist device infection treated with frozen-and-thawed allogeneic platelet gel.

In this case report, we report the application of frozen-and-thawed allogeneic platelet gel (PLT-gel) to treat a late driveline exit site infection in a 56-year old patient supported by a Heartware-HVAD left ventricular assist device. The treatment duration was 4 weeks and at the follow-up the skin around the exit site was free from further infection. PLT-gel can be used to treat local infection of the driveline exit site and to prevent further high-risk infections.

Cardiovascular variability is similarly altered in coronary patients with normal left ventricular function and in heart failure patients.

OBJECTIVE: After myocardial infarction (MI), baroreflex function is impaired and heart rate (HR) variability is reduced. An impaired baroreflex has been observed also in coronary patients with no previous MI, leading to hypothesize alterations of HR variability also in these patients. The aim of the present work was, therefore, to study whether and to what extent cardiovascular variability is altered in coronary patients with no previous MI. METHODS: Thirty-two individuals were studied: eleven patients with coronary artery disease but no previous MI [coronary artery disease (CAD)], eleven patients with a reduced left ventricular ejection fraction [congestive heart failure (CHF)] and ten age-matched controls (CNT). RESULTS: Overall HR variability was significantly and similarly reduced in CAD (630 ±â€Š272 ms) and CHF patients (594 ±â€Š395 ms) with respect to CNT (1405 ±â€Š837 ms), this being the case also for the low and high frequency spectral components. Low-frequency oscillations of blood pressure (BP) were also significantly and similarly less pronounced in CAD (0.7 ±â€Š0.7 mmHg) and CHF patients (0.7 ±â€Š0.7 mmHg) compared with CNT (1.8 ±â€Š1.4 mmHg). Moreover, both CAD and CHF patients showed a significantly reduced baroreflex function and an increased pulse-wave velocity with respect to CNT. CONCLUSION: Our study shows that in coronary patients with no MI and no left ventricular dysfunction, there is a profound alteration of both HR and BP variability as in CHF patients, presumably because of a marked impairment of the autonomic modulation of the heart and blood vessels.

Fatal huge left free wall ventricular rupture after acute posterior myocardial infarction.

A 77-year-old man, with a recent history of an acute inferior myocardial infarction, was referred to our hospital with echocardiographic and clinical signs of left ventricular free wall rupture (LVFWR). The intraoperative finding demonstrated a huge double LVFWR. The inferoposterior wall was dramatically destroyed without any possibility to repair.