Mid-term outcome and angiographic follow-up of endarterectomy of the left anterior descending artery in patients undergoing coronary artery bypass surgery.

BACKGROUND AND AIM: With the advancement of percutaneous coronary interventions (PCIs), more patients with diffuse coronary artery disease are referred for coronary artery bypass graft (CABG) surgery. The use of coronary endarterectomy may be useful in such cases. We reviewed our experience with left anterior descending artery endarterectomy as an adjunct to conventional CABG. METHODS: Between June 2005 and 2011, 58 consecutive patients underwent left anterior descending artery endarterectomy as an adjunct to CABG. These were matched to 58 cases based on age, gender, and Parsonnet score. All data were collected prospectively in a departmental database. Postoperative complications and in-hospital mortality were analyzed. Survival curves were produced. RESULTS: There was one death in the endarterectomy group (1.7%) from liver failure. There was no significant difference in postoperative complications (especially perioperative myocardial infarction) between the two groups with similar hospital mortality. Computed tomography (CT) angiography was performed in 24 patients with endarterectomy (41%), which showed 100% patency of the left internal mammary artery graft to the left anterior descending artery. Survival and freedom from intervention at a mean follow-up of 4.2 years were similar. CONCLUSIONS: In patients with diffuse disease, the use of endarterectomy is a safe technique with no increase in short-term morbidity or mortality. Mid-term results are similar to nonendarterectomized patients. This technique is useful in patients with diffuse coronary artery disease.

Preoperative hospital length of stay as a modifiable risk factor for mediastinitis after cardiac surgery.

BACKGROUND: As high-risk cardiac patients frequently remain within hospital while waiting for surgery, the aim of the present study was to determine the role of preoperative length of hospital stay on mediastinitis, and also, to assess contemporary risk factors for this complication. METHODS: The source population consisted of 6653 consecutive patients undergoing coronary bypass surgery, valve surgery, or both between September 2000 and September 2009 at a single tertiary care hospital. A retrospective cohort analysis was used to assess the effect of 18 preoperative variables, including length of stay, on mediastinitis. RESULTS: Mediastinitis developed in 108 patients (1.6%) resulting in an in-hospital mortality rate of 13.9%. Independent predictors of mediastinitis included obesity (2.59, CI 1.58-4.23), COPD (2.44, CI 1.55-3.84), diabetes (2.16, CI 1.44-3.24), and impaired estimated glomerular filtration rate. Preoperative hospital stay was also found to be an independent risk factor leading to a 15% increased risk of mediastinitis per week of stay. The primary wound pathogen was coagulase negative staphylococcus (82%) followed by multi-flora isolates (49%), but was unrelated to hospital stay. CONCLUSIONS: In addition to the traditional risk factors, prolonged preoperative hospital stay is also a significant and potentially modifiable predictor for the development of mediastinitis following cardiac surgery. All efforts should be made to minimize the delay in operating on hospitalized patients awaiting heart surgery.

Mitochondrial dysfunction and lipid accumulation in the human diaphragm during mechanical ventilation.

RATIONALE: Mechanical ventilation (MV) is associated with adverse effects on the diaphragm, but the cellular basis for this phenomenon, referred to as ventilator-induced diaphragmatic dysfunction (VIDD), is poorly understood. OBJECTIVES: To determine whether mitochondrial function and cellular energy status are disrupted in human diaphragms after MV, and the role of mitochondria-derived oxidative stress in the development of VIDD. METHODS: Diaphragm and biceps specimens obtained from brain-dead organ donors who underwent MV (15-176 h) and age-matched control subjects were compared regarding mitochondrial enzymatic function, mitochondrial DNA integrity, lipid content, and metabolic gene and protein expression. In addition, diaphragmatic force and oxidative stress after exposure to MV for 6 hours were evaluated in mice under different conditions. MEASUREMENTS AND MAIN RESULTS: In human MV diaphragms, mitochondrial biogenesis and content were down-regulated, with a more specific defect of respiratory chain cytochrome-c oxidase. Laser capture microdissection of cytochrome-c oxidase-deficient fibers revealed mitochondrial DNA deletions, consistent with damage from oxidative stress. Diaphragmatic lipid accumulation and responses of master cellular metabolic sensors (AMP-activated protein kinase and sirtuins) were consistent with energy substrate excess as a possible stimulus for these changes. In mice, induction of hyperlipidemia worsened diaphragmatic oxidative stress during MV, whereas transgenic overexpression of a mitochondria-localized antioxidant (peroxiredoxin-3) was protective against VIDD. CONCLUSIONS: Our data suggest that mitochondrial dysfunction lies at the nexus between oxidative stress and the impaired diaphragmatic contractility that develops during MV. Energy substrate oversupply relative to demand, resulting from diaphragmatic inactivity during MV, could play an important role in this process.

Functional quality of life following open valve surgery in high-risk octogenarians.

AIM: The aim of this study was to determine the midterm functional quality of life in octogenarians after open valvular surgery. METHODS: One hundred and eighty-five consecutive patients above age 80 had valvular surgery with or without coronary artery bypass grafting (CABG). Using the Karnofsky Performance score and Barthel Index, patients were evaluated for functional autonomy, living disposition, and leisure activity by a single telephone interview. Subgroup analysis was performed on the 49 cases of isolated aortic valve replacement (AVR). RESULTS: Mean age of octogenarians undergoing valvular surgery was 82.7 years (range 80 to 92 years). Actuarial survival at one and three years was 71% and 59%, respectively, for the entire group, compared to 84% and 71%, respectively, for isolated AVRs. After a mean follow-up of 38 months there were 110 survivors (59.5%). Among survivors, 66% were autonomous, 26% semiautonomous, and 8% deemed dependent. Seventy-two percent were living at home, 19% in a residence, and 9% in a supervised nursing facility. Over 90% of patients pursued leisure activities in the social, cognitive, and physical domains. CONCLUSIONS: Valvular surgery in high-risk octogenarians, can be performed with acceptable mortality rates, and provide patients with functional autonomy and an excellent quality of life.

Continuous positive airway pressure versus continuous negative pressure around the chest for patients with acute exacerbation of chronic obstructive pulmonary disease in the intensive care unit: a pilot study.

INTRODUCTION: With chronic obstructive pulmonary disease (COPD) exacerbations, continuous positive airway pressure (CPAP) has been used to overcome the threshold load provided by intrinsic positive end expiratory pressure and decrease the inspiratory work of breathing. In this pilot study, we observed whether a continuous negative pressure (CNP) around the thorax and upper abdomen with a shell and wrap would provide a similar level of relief in dyspnoea. METHODS: In eight patients with COPD in the intensive care unit receiving CPAP, CNP was alternated twice with CPAP (30 minutes each time). We measured heart rate, respiratory rate, blood pressure, arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2) pH and dyspnoea score, and asked each patient which system was more comfortable. RESULTS: Comparing CPAP with CNP, we found no significant difference in all measured parameters except PaCO2 which was lower with CNP. Seven out of eight patients found that CNP was more comfortable. CONCLUSIONS: The CNP was similar to CPAP except CNP was more comfortable.

Use of continuous negative pressure around the chest increases exercise performance in chronic obstructive pulmonary disease patients: a pilot study.

BACKGROUND: Patients with severe chronic obstructive pulmonary disease (COPD) often have intrinsic positive end-expiratory pressure. Continuous positive airway pressure has been shown to decrease the inspiratory work of breathing and increases exercise capacity in these patients. OBJECTIVE: To determine whether continuous negative pressure (CNP) around the chest is able to bring the positive end-expiratory pressure closer to atmospheric pressure, thereby reducing the threshold load and increasing exercise capability. METHODS: A pilot study was undertaken with eight COPD patients who had been hospitalized for exacerbation and were close to discharge. For CNP, a shell (around the thorax from under the axillae to the mid abdomen) and wrap were used. Each of the eight patients was assessed with a 6 min walk test in three modes (in randomized order) with 30 min of rest in between: a control walk with no shell or wrap; a sham CNP in which the applied CNP was negligible; and CNP, with pressure chosen by the patient that provided maximal relief of dyspnea at rest. RESULTS: At the end of each of the 6 min walk tests, there was no difference in heart rate, oxygen saturation or level of dyspnea among the three test modes. Respiratory rate was reduced with CNP compared with sham. The patients walked furthest with CNP compared with control (mean ± SD) (313 ± 66.2 m versus 257 ± 65.2 m; P<0.01) and compared with sham. CONCLUSIONS: In the present pilot study, COPD patients improved their exercise performance with CNP.

Mechanical ventilation-induced diaphragm disuse in humans triggers autophagy.

RATIONALE: Controlled mechanical ventilation (CMV) results in atrophy of the human diaphragm. The autophagy-lysosome pathway (ALP) contributes to skeletal muscle proteolysis, but its contribution to diaphragmatic protein degradation in mechanically ventilated patients is unknown. OBJECTIVES: To evaluate the autophagy pathway responses to CMV in the diaphragm and limb muscles of humans and to identify the roles of FOXO transcription factors in these responses. METHODS: Muscle biopsies were obtained from nine control subjects and nine brain-dead organ donors. Subjects were mechanically ventilated for 2 to 4 hours and 15 to 276 hours, respectively. Activation of the ubiquitin-proteasome system was detected by measuring mRNA expressions of Atrogin-1, MURF1, and protein expressions of UBC2, UBC4, and the α subunits of the 20S proteasome (MCP231). Activation of the ALP was detected by electron microscopy and by measuring the expressions of several autophagy-related genes. Total carbonyl content and HNE-protein adduct formation were measured to assess oxidative stress. Total AKT, phosphorylated and total FOXO1, and FOXO3A protein levels were also measured. MEASUREMENTS AND MAIN RESULTS: Prolonged CMV triggered activation of the ALP as measured by the appearance of autophagosomes in the diaphragm and increased expressions of autophagy-related genes, as compared with controls. Induction of autophagy was associated with increased protein oxidation and enhanced expression of the FOXO1 gene, but not the FOXO3A gene. CMV also triggered the inhibition of both AKT expression and FOXO1 phosphorylation. CONCLUSIONS: We propose that prolonged CMV causes diaphragm disuse, which, in turn, leads to activation of the ALP through oxidative stress and the induction of the FOXO1 transcription factor.

Cardiac surgery in octogenarians: long-term survival, functional status, living arrangements, and leisure activities.

BACKGROUND: A prospective study of survival, functional outcome, living arrangements, daily activities and leisure engagements among octogenarians up to 5 years after cardiac surgery was performed. METHODS: The study consisted of a cohort of 300 consecutive octogenarians with three interviews made at 6-month intervals for a total of 593 postoperative interviews. Functional outcomes were measured using the Barthel index and Karnofsky performance scores and divided into autonomous, semiautonomous, or dependent. Living arrangements and leisure activities within the social, physical, cognitive, and creative domains were recorded in an open-ended questionnaire. RESULTS: There were 150 men and 150 women with a mean age 82.6 years. The 30-day survival was 84.3%. Actuarial survival at 1, 3, and 5 years was 76.6%, 66.6%, and 57.8%, respectively. Among the survivors at the first interview, 2.2 years postoperatively, there were 63.9% autonomous, 31.7% semiautonomous, and 4.3% dependent patients versus at the last interview, 3.6 years postoperatively, in which there were 64.9% autonomous, 28.1% semiautonomous, and 9.2% dependent. At the first interview, 76.4% were at home, 19.2 % in a residence, and 4.3% in a supervised setting. At the third interview, 71.8% were at home, 21.2% in a residence, and 6.9% in a supervised setting. Nearly all patients were involved in leisure activities in the social (98.9%), cognitive (98.4%), and physical (93.1%) domains. At the end of the last interview, activities within the social and cognitive domains were maintained with a small decrease in the physical domain. CONCLUSIONS: Surviving octogenarians remain at home, function independently, and engage in regular leisure activities years after cardiac surgery. This information might help physicians and surgeons regarding long-term outcome of open cardiac surgery in octogenarians.

Initial results of posterior leaflet extension for severe type IIIb ischemic mitral regurgitation.

BACKGROUND: Management of severe ischemic mitral regurgitation remains difficult with disappointing early and intermediate-term surgical results of valve repair. METHODS AND RESULTS: Forty-four patients with severe (4+) Carpentier type IIIb ischemic mitral regurgitation underwent mitral valve repair, with or without surgical revascularization, by posterior leaflet extension with a patch of bovine pericardium and a remodeling annuloplasty. Serial echocardiography was performed preoperatively, intraoperatively, and postoperatively to assess mitral valve competence. The postoperative functional status of patients was assessed. The average Parsonnet score was 38+/-13. Thirty-day mortality was 11%, and late mortality was 14%. Mean follow-up was 38 months. The actuarial freedom from moderate or severe recurrent mitral regurgitation was 90% at 2 years, whereas 90% of patients were in New York Heart Association class I at 2 years. CONCLUSIONS: Posterior leaflet extension with annuloplasty of the mitral valve for severe type IIIb ischemic regurgitation is a safe, effective method that provides good early and intermediate-term competence of the mitral valve and therefore good functional status.

The effect of using microplegia on perioperative morbidity and mortality in elderly patients undergoing cardiac surgery.

Old age is a significant risk factor for perioperative morbidity and mortality following cardiac surgery and optimal myocardial protection strategy should be sought in this group of patients. We, therefore, reviewed the data on 295 consecutive patients older than 75 years who underwent any cardiac surgical procedure. Microplegia was used in 144 patients compared to 151 patients who had the standard 4:1 blood cardioplegia. Logistic regression analysis was used for propensity matching to balance the differences between the two groups. The microplegia group included more females and sicker patients as indicated by higher Parsonnet scores. There were differences in the pump time, aortic cross-clamp time, procedure type and surgeons between the two groups. These differences were balanced using the propensity matching. In-hospital mortality, acute renal injury and confusion were higher in the microplegia group (17%, 34%, 35%, respectively) compared to the standard 4:1 cardioplegia group (9%, 23%, 24%, respectively) (P=0.04, 0.04, 0.04, respectively). These differences were not statistically significant after propensity matching. These results demonstrate that the use of microplegia is safe in patients older than 75 years who are undergoing cardiac surgery and results in similar in-hospital morbidity and mortality to the standard 4:1 blood cardioplegia.

Use of negative extrathoracic pressure to improve hemodynamics after cardiac surgery.

BACKGROUND: Little attention is given to the mode of mechanical ventilation after cardiac surgery. Positive pressure ventilation with positive end-expiratory pressure (PEEP) has been shown to reduce cardiac output. We hypothesized that positive pressure ventilation with continual negative pressure applied to the chest through a cuirass would increase cardiac output in coronary artery bypass graft patients immediately after surgery. METHODS: Twenty patients with a normal left ventricular ejection fraction were studied 2 hours after coronary artery bypass graft surgery. The patients were ventilated with synchronized intermittent mandatory ventilation (SIMV) and PEEP. Hemodynamic variables and blood gases were studied using four modes of ventilation after 15 minutes in each mode: A (baseline 1) = SIMV and 5 cmH(2)O of PEEP; B = SIMV without PEEP; C = SIMV without PEEP and with continuous negative pressure applied to the thorax at -20 cmH(2)O; D (baseline 2) = SIMV and 5 cmH(2)O of PEEP. The results of the two baselines were averaged. RESULTS: All patients were hemodynamically stable during the trial. Heart rate, blood pressure, and gas exchange were not affected by the changes in ventilatory modes. With continual negative pressure, the stroke volume index and cardiac index were significantly increased relative to ventilation with SIMV and PEEP by 3.21 mL x min(-1) x m(-2) (9.0%) and 0.45 L x min(-1) x m(-2) (13.8%), respectively. Continual negative pressure also reduced venous and wedge pressure. CONCLUSIONS: Continual negative pressure attenuates the negative effects of positive pressure ventilation on cardiac output. Although the improvement in this cohort with normal ventricular function is modest, this pilot study demonstrates that the mode of ventilation may have potentially important effects on cardiac output.