Explantation of infected aortic aneurysm and endograft with ascending aorta to mesenteric bypass for mesenteric ischemia.

A 65-year-old man presented with an infected perivisceral aortic aneurysm after previous treatment of an abdominal aortic aneurysm with an endograft. On presentation, he was septic and had occlusion of the celiac, superior mesenteric, inferior mesenteric, and bilateral renal arteries. He underwent a three-stage procedure: first, axillobifemoral bypass; then resection of the thoracoabdominal aorta; and finally bypass from the ascending aorta to the celiac and superior mesenteric arteries with a rifampin-soaked Gelsoft graft (Vascutek, Renfrewshire, Scotland). The abdominal pain resolved, and the patient remains symptom free 10 months postoperatively. This rare surgical revascularization technique offered a nontraditional solution to a difficult surgical issue.

Machine Learning in Cardiac Surgery: Predicting Mortality and Readmission.

Predicting outcomes in open-heart surgery can be challenging. Unexpected readmissions, long hospital stays, and mortality have economic implications. In this study, we investigated machine learning (ML) performance in data visualization and predicting patient outcomes associated with open-heart surgery. We evaluated 8,947 patients who underwent cardiac surgery from April 2006 to January 2018. Data visualization and classification were performed at cohort-level and patient-level using clustering, correlation matrix, and seven different predictive models for predicting three outcomes ("Discharged," "Died," and "Readmitted") at binary level. Cross-validation was used to train and test each dataset with the application of hyperparameter optimization and data imputation techniques. Machine learning showed promising performance for predicting mortality (AUC 0.83 ± 0.03) and readmission (AUC 0.75 ± 0.035). The cohort-level analysis revealed that ML performance is comparable to the Society of Thoracic Surgeons (STS) risk model even with limited number of samples ( e.g. , less than 3,000 samples for ML versus more than 100,000 samples for the STS risk models). With all cases (8,947 samples, referred as patient-level analysis), ML showed comparable performance to what has been reported for the STS models. However, we acknowledge that it remains unknown at this stage as to how the model might perform outside the institution and does not in any way constitute a comparison of the performance of the internal model with the STS model. Our study demonstrates a systematic application of ML in analyzing and predicting outcomes after open-heart surgery. The predictive utility of ML in cardiac surgery and clinical implications of the results are highlighted.

Echocardiography fails to detect an extensive aortic root abscess in a patient with infective endocarditis: a case report.

Background: Echocardiography plays a central role in the diagnosis of infective endocarditis (IE). In recent years, additional imaging techniques have begun to challenge the conventional approach. We present a case where the use of transthoracic/transoesophageal echocardiography (TTE/TOE) in suspected IE failed to identify an extensive periannular abscess, later identified by 18F-flurodeoxyglucose-positron emission tomography (FDG-PET), requiring urgent intervention. Case summary: A 69-year-old man with symptomatic Streptococcus sanguinis bacteraemia and a bicuspid aortic valve was found to have new-onset left bundle branch block that progressed to complete heart block. After starting on IV Penicillin G and having a temporary pacemaker inserted, his clinical condition improved. Transthoracic echocardiography and TOE showed no evidence of abscess. However, persistent first-degree atrioventricular block raised clinical suspicion of a possible extended infection. Subsequent FDG-PET revealed focal activity around the aortic root that extended inferiorly into the interatrial septum, consistent with active infection and possible abscess. Composite aortic root replacement with insertion of a mechanical prosthesis was carried out, revealing extensive IE and multiple periannular abscesses. Discussion: As guidelines grapple with evolving understandings of how best to define the optimal imaging approach for the management of complicated IE, the results of this case clearly show the importance of heightened clinical suspicion and need for prompt operative intervention when faced with patients who present with predisposing conditions and concern for advanced conduction disease. Clinicians and researchers are encouraged to learn from the potential near-miss of an extensive periannular abscess to help guide guideline-development of imaging in complicated IE and prevent adverse outcomes in patients with similar presentations.

Mathematical Blueprint of a Mitral Valve.

Mathematical modeling tries to simplify understanding and proposes a fundamental mechanism that governs the motion and function of a complex biological system such as a mitral valve (MV) motion which represents a dynamic interplay between papillary muscle (PM) position in the context of left ventricular (LV) shape dynamics. Current therapeutic strategies to intervene on the MV may not have exploited these relationships due to lack of understanding of the interactions. We present a MV 3D mathematical model characterized by LV shape dynamics to understand fundamental working principles of ventriculo-papillary-mitral complex. A complex 3D functional unit of MV apparatus was mathematically modeled based on a principle of dynamics. The model comprises of primary components including the annulus, anterior leaflet, posterior leaflet, chordae tendineae, anterior and posterior PM, and LV wall based on normal anatomical reference values from published series. Simulations based on Carpentier's classification of MV disease were created as well as based on LV shape dynamics and presented graphically. Autodesk Inventor (Autodesk Inc., San Rafael, CA) and Matlab (Mathworks, Natick, MA) were used for modeling and analysis. A stepwise analysis and mathematical models of the annulus, leaflets, chords, PMs, and LV were obtained by combining finite element analysis and computerized model creations. The model was then applied to Carpentier's functional classification. PM positions extrapolated based on different LV deformation in normal and mitral regurgitation (MR) model resulted in a different degree of MV leaflet coaptation with regurgitation (presented numerically and graphically). Abnormal MV coaptation was amended by manipulating PM positions independent with LV size or shape deformation, demonstrating that PM positioning maneuver may improve leaflet coaptation. LV dilation combined with increased interpapillary muscle distance turned out to intensify the level of leaflet prolapse, creating even greater regurgitation volume. Our mathematical model may provide a clue to complex interactions in play within a mitral, papillary, and LV complex. The model offers a possibility of manipulating various variables to obtain the desired outcome.

Plasma Levels of MicroRNA-155 Are Upregulated with Long-Term Left Ventricular Assist Device Support.

Left ventricular assist device (LVAD) therapy unloads the failing heart but exposes the human body to unique pathophysiologic demands such as continuous blood flow and complete univentricular support, which are associated with increased risk of adverse clinical outcomes. MicroRNAs (miRNAs) are 22-23 nucleotide RNAs involved in regulation of multiple biologic processes including the pathogenesis of heart failure (HF). Thus, measurement of miRNAs may have potential in both diagnostics as circulating biomarkers and in therapeutics for targeted interventions. We examined 23 distinct miRNAs that have previously been shown to play a role in HF pathogenesis and measured them in 40 individuals both before continuous-flow LVAD implantation and at a median of 96.5 days after implantation. Quantitative real-time polymerase chain reaction was performed for miRNA amplification, and 19 miRs were included in statistical analysis. Wilcoxon signed-rank tests were used to compare within-patient median relative quantification values pre- and post-LVAD placement. The median age of patients was 67 years, and 57.5% were at Interagency Registry for Mechanically Assisted Circulatory Support level 1-2. After LVAD support, only miR-155 was found to be statistically significant (p < 0.002), with an upregulation in plasma expression levels with LVAD support, which persisted regardless of the direction of change in serial HF biomarker levels. MicroRNA-155, which has been shown to play a central role in inflammation and neovascularization, was upregulated with long-term LVAD support. If validated by future studies, miR-155 may help further inform on underlying LVAD physiology and has a role as a therapeutic target in this patient population.

Aortic valve replacement and concomitant mitral valve regurgitation in the elderly: impact on survival and functional outcome.

BACKGROUND: The impact of mitral regurgitation (MR) on elderly patients (> or = 70 years) undergoing isolated aortic valve replacement (AVR) is not clearly defined. This study investigates the long-term effects of preoperative, moderate MR on survival and functional outcome in elderly AVR patients. METHODS AND RESULTS: A retrospective review identified 408 consecutive elderly patients who underwent isolated AVR from January 1983 to February 2004. The pathologic etiology of MR was determined on preoperative echocardiogram, and patients were stratified into no/mild MR (Group I; n = 338) versus moderate MR (Group II; n = 70). Follow-up was 95.1% complete. Functional outcome was evaluated using the Short Form-12 questionnaire. On univariate analysis, Groups I and II differed in incidence of previous myocardial infarction (13.9% versus 28.6%; P = 0.004), hyperlipidemia (18.7% versus 33.3%; P = 0.009), and congestive heart failure (50.0% versus 70.0%; P = 0.002). On multivariate analysis, moderate MR was an independent risk factor impacting long-term survival (P = 0.04). Actuarial survival at 1, 5, and 10 years for Group I was 93.8%, 73.3%, and 40.1% versus 92.3%, 58.2%, and 14.6% for Group II (P = 0.04). Available postoperative echocardiograms for Group II (n = 37) demonstrated improvement in MR in 81.8% of functional MR patients. However, MR persisted or worsened in 65.4% of patients with intrinsic mitral valve disease (myxomatous, calcific, or ischemic MR). Functional outcomes showed 77% of Group I versus 78.6% of Group II rated their health as good to excellent post-AVR. CONCLUSIONS: Moderate MR is an independent risk factor impacting long-term survival in elderly patients undergoing AVR. Therefore, patients with intrinsic mitral valve disease should be considered for concomitant MV surgery.

Impact of donor lung organisms on post-lung transplant pneumonia.

BACKGROUND: Fear of transmission of donor organisms that may result in recipient pneumonia has a negative impact on donor lung utilization. We reviewed our experience with routine donor bronchial aspiration and culture at the time of transplantation to study the impact of donor bronchial organisms on the development of recipient post-lung transplant pneumonia (PTP) and other outcomes. METHODS: We reviewed 80 consecutive single and bilateral lung transplants (SLTs and BLTs) from August 1998 to August 2001. Pediatric recipients and those not surviving >3 days were excluded. All donors met standard criteria for donor acceptance. All recipients received broad-spectrum antibiotics pending the results of final operating room cultures. PTP required clinical evidence (fever, leukocytosis and hypoxia), radiologic evidence (infiltrate), and culture confirmation during initial hospitalization or within 30 days. RESULTS: Sixty-four donors for 71 recipients (39 SLTs, 32 BLTs) comprised the study population. Organisms were grown from 57 (89%) donors and 46 were polymicrobial. A total of 149 organisms were cultured consisting of 21 different species, with Staphylococcus (n = 35) and Streptococcus (n = 33) being the most common. PTP was seen in 31 (41%) recipients, with Pseudomonas species (n = 13) the most prevalent. Of the 71 donor-recipient pairs, 2 had both donor and recipient with no growth and PTP. The donor organisms had a sensitivity of 0.75 with a low specificity of 0.04 and were negatively correlated with development of PTP. PTP was an independent predictor of overall mortality. CONCLUSIONS: The presence of donor organisms does not predict PTP. Therefore, donor acceptance criteria need to be re-examined.

Clinical outcomes of noninfectious sternal dehiscence after median sternotomy.

BACKGROUND: Infectious complications of median sternotomy carry significant morbidity and mortality. However, the outcomes of noninfectious sternal dehiscence have not been addressed. We have identified the preoperative characteristics, postoperative complications, and long-term functional outcomes of patients after reoperation for noninfectious sternal dehiscence and compared these patients with a control group to determine risk factors for dehiscence. METHODS: Retrospective review of the cardiac surgery database identified 48 patients with noninfectious sternal dehiscence in a group of 12,380 median sternotomies between 1994 and 2004. The review included diagnosis, demographics, concomitant medical conditions, and surgical outcomes. Functional outcomes were assessed using the Short Form-12 questionnaire. One hundred fifty-six median sternotomy patients served as controls. Follow-up was 97.9% (47 of 48 patients) complete, for a total of 150.1 patient-years. RESULTS: Mean age of patients at reoperation was 58.8 +/- 12.8 years, with a male to female ratio of 45:3. Multivariate analysis determined that New York Heart Association class IV, obesity, and chronic obstructive pulmonary disease were preoperative risk factors for sternal dehiscence. The incidence of sternal dehiscence was 0.39% at a mean interval between initial operation and reoperation of 5.4 months. At a mean interval of 3.9 months, 14.6% (7 of 48) of patients required additional sternal procedures. Infectious complications after reoperation occurred in 12.5% (6 of 48). Functional outcomes demonstrated that 72.2% (26 of 36) had no or mild limitation of physical activities, with 90.5% (38 of 42) reporting no or mild sternal pain at follow-up. CONCLUSIONS: Although patients undergoing surgical correction of noninfectious sternal dehiscence fare better than those with infectious complications, optimal sternal approximation during the initial procedure and sternal precautions during convalescence should be emphasized to prevent recurrent complications.

Attenuation of DNA damage in canine hearts preserved by continuous hypothermic perfusion.

BACKGROUND: Continuous hypothermic perfusion is a novel cardiac preservation technique. Reactive oxygen species play a role in ischemia reperfusion injury and limit organ preservation. Oxidative stress mediates a DNA mismatch lesion (7, 8-dihydro-8-oxoguanine [8-oxo-G]), which is repaired by the enzymes MutY homologue (MYH), 8-oxo-G glycosylase (OGG1), and MutS homologue 2 (MSH2). We hypothesized that continuous hypothermic perfusion would allow for maintenance of cardiac function while attenuating myocardial DNA damage with respect to the current clinical practice of static preservation at 4 degrees C. METHODS: In our canine orthotopic transplant model, donor hearts were harvested after echocardiograms, and hemodynamic studies were obtained and served as controls. The hearts were transplanted after 24 hours of continuous hypothermic perfusion or 4 hours of static preservation, and were studied for 6 hours. Quantification of 8-oxo-G lesions, MYH, OGG1, and MSH2 concentrations were performed on biopsies using immunohistochemistry. RESULTS: Postimplant echocardiograms, completed in 7 continuously perfused and 8 statically preserved hearts, demonstrated good function and normal wall motion. Positive staining for 8-oxoG was markedly increased in the static preservation group. Staining density for MYH, OGG1, and MSH2 were significantly decreased in statically preserved hearts and equivalent between continuously perfused and control hearts. CONCLUSIONS: The DNA damage assayed by 8-oxoG was significantly increased in statically preserved versus continuously perfused hearts. The DNA repair enzymes MYH, OGG1, and MSH2 were also markedly decreased in the static preservation versus continuous hypothermic perfusion groups. Continuous hypothermic perfusion reduces oxidative damage and extends preservation without compromising function.

Surgical ventricular remodeling for multiterritory myocardial infarction: defining a new patient population.

OBJECTIVE: Because of limited medical and surgical options for patients with end-stage congestive heart failure, we expanded the criteria for surgical ventricular remodeling to include patients with multiterritory myocardial infarction, a group historically considered high-risk candidates. We present our series of patients with multiterritory myocardial infarction who underwent surgical ventricular remodeling and propose a new patient population who may benefit from this procedure. METHODS: Data were analyzed for 51 consecutive patients undergoing surgical ventricular remodeling from January 2002 to June 2004, with 100% follow-up. Three left ventricular vascular territories were defined: anteroapicoseptal (left anterior descending), lateral (circumflex), and inferior (right coronary artery). Infarction was assessed with magnetic resonance imaging and intraoperative findings. RESULTS: Multiterritory myocardial infarction was found in 64.7% of patients (33/51) undergoing surgical ventricular remodeling. Mean age was 61.6 +/- 11.1 years (range 40-81 years). Sixty-one percent (20/33) demonstrated evidence of myocardial infarction in all three territories. Five patients underwent concomitant mitral valve repair or replacement. Operative mortality was 6.1% (2/33) and did not differ from that of patients with single-territory infarction (11.1%, P = .61). Surgical ventricular remodeling significantly improved left ventricular volumes and ejection fraction in patients with multiterritory myocardial infarction. Three patients required assist device implantation, and 2 patients required defibrillator placement. Sixty-nine percent of patients in preoperative New York Heart Association functional class III or IV (22/32) had improvement to class I or II at follow-up (P < .01). Cox regression analysis discriminated a preoperative left ventricular end-systolic volume index greater than 100 mL/m(2) as a significant risk factor for mortality (odds ratio 12.1, 95% confidence interval 1.27-114.51, P = .03). Thirty-month survival of patients with multiterritory myocardial infarction (73.5% +/- 8.3%) did not differ statistically from that of patients with single-territory infarction (n = 18). CONCLUSION: Surgical ventricular remodeling improves cardiac function and New York Heart Association functional status in patients with multiterritory myocardial infarction. Our initial results are promising and should prompt further studies to confirm our results and potentially expand the surgical ventricular remodeling inclusion criteria to include patients with multiterritory myocardial infarction.

Surgical ventricular remodeling for patients with clinically advanced congestive heart failure and severe left ventricular dysfunction.

BACKGROUND: Surgical ventricular remodeling (SVR) is an accepted therapy for post-infarction ventricular remodeling. Current literature on SVR outcomes has focused on heterogeneous populations with regard to left ventricular function and New York Heart Association (NYHA) class. We assessed outcomes after SVR in patients with advanced congestive heart failure (CHF) (NYHA Class III/IV) and a pre-operative ejection fraction (EF) < or =20%. METHODS: Data were analyzed for 51 consecutive SVR patients from January 2002 to June 2004. Cardiac catheterization, echocardiography and magnetic resonance imaging (MRI) identified 62.7% (32 of 51) of patients with an EF < or =20%, with the majority having an EF < or =15% (65.6%; 21 of 32). Cox regression analysis was performed to determine predictors of mortality in patients with an EF < or =20%. Follow-up was 100% (32 of 32) complete. RESULTS: Mean age was 61.9 +/- 10.3 (range 40 to 80) years with a male:female ratio of 27:5. Operative mortality was 6.3% (2 of 32). Twenty-two percent (7 of 32) had concomitant mitral valve procedures. Follow-up demonstrated a statistically significant improvement in left ventricular volumes and EF in survivors. Cox regression analysis identified the following to be significant predictors of mortality: pre-operative left ventricular end-systolic volume index >130 ml/m2; pre-operative diabetes; and intra-aortic balloon pump usage. Pre-operatively, all patients (32 of 32) were categorized as NYHA Class III/IV, with 69% (22 of 32) improving to NYHA Class I/II at follow-up (p < 0.01). Survival did not differ statistically between patients with an EF < or =20% and an EF >20% (n = 19). CONCLUSIONS: Our results indicate that SVR improves left ventricular function and functional status for patients with advanced CHF and a pre-operative EF < or =20%. Therefore, SVR is a viable surgical alternative for patients with severe left ventricular dysfunction.