Topical Ice Slush Adversely Affects Sniff Nasal Inspiratory Force After Coronary Bypass Surgery.

BACKGROUND: Topical cooling with ice slush as an adjunct for myocardial protection during cardiac surgery has been shown to cause freezing injury of the phrenic nerves. This can cause diaphragmatic dysfunction and respiratory complications. METHODS: Twenty (n=20) male patients between the ages of 40 and 60 years were equally randomised to undergo elective coronary artery bypass grafting (CABG) with either cold cardioplegic arrest with topical ice slush cooling or cold cardioplegic arrest without the use of ice slush. The sniff nasal inspiratory force (SNIF) was used to compare inspiratory muscle strength. RESULTS: There was no difference in the preoperative SNIF in the two randomised groups. In the immediate postoperative period, the ice slush group had worse SNIF (33.5±9.6cm H2O versus 47.8±12.2cm H2O; p=0.009). The pre-home discharge SNIF was still significantly lower for the ice slush group despite a noted improvement in SNIF recovery in both groups (38.3±10.6cm H2O versus 53.5±13.2cm H2O; p=0.011). Two patients in the ice slush group had left diaphragmatic dysfunction with none in the control group. CONCLUSION: The use of topical ice slush is associated with freezing injury of the phrenic nerves. This will adversely affect the inspiratory muscle force which may lead to respiratory complications after surgery.

Assessment of Image Quality of Repeated Limited Transthoracic Echocardiography After Cardiac Surgery.

OBJECTIVES: The use of limited transthoracic echocardiography (TTE) has been restricted in patients after cardiac surgery due to reported poor image quality. The authors hypothesized that the hemodynamic state could be evaluated in a high proportion of patients at repeated intervals after cardiac surgery. DESIGN: Prospective observational study. SETTING: Tertiary university hospital. PARTICIPANTS: The study comprised 51 patients aged 18 years or older presenting for cardiac surgery. INTERVENTIONS: Patients underwent TTE before surgery and at 3 time points after cardiac surgery. Images were assessed offline using an image quality scoring system by 2 expert observers. Hemodynamic state was assessed using the iHeartScan protocol, and the primary endpoint was the proportion of limited TTE studies in which the hemodynamic state was interpretable at each of the 3 postoperative time points. MEASUREMENTS AND MAIN RESULTS: Hemodynamic state interpretability varied over time and was highest before surgery (90%) and lowest on the first postoperative day (49%) (p<0.01). This variation in interpretability over time was reflected in all 3 transthoracic windows, ranging from 43% to 80% before surgery and from 2% to 35% on the first postoperative day (p<0.01). Image quality scores were highest with the apical window, ranging from 53% to 77% across time points, and lowest with the subcostal window, ranging from 4% to 70% across time points (p< 0.01). CONCLUSIONS: Hemodynamic state can be determined with TTE in a high proportion of cardiac surgery patients after extubation and removal of surgical drains.

Use of the guidelines directed medical therapy after coronary artery bypass graft surgery in Saudi Arabia.

Background: incidence of cardiovascular diseases in Saudi Arabia is growing and more patients are expected to have cardiac revascularization surgery. Optimal pharmacotherapy management with Guideline Directed Medical Therapy (GDMT) post coronary artery bypass grafting (CABG) plays an important role in the prevention of adverse cardiovascular outcomes. The objective of this study was to assess the utilization of GDMT for secondary prevention in CABG patients and determine whether specific patients' characteristics can influence GDMT utilization. Method: A retrospective chart review of patients discharged from the hospital after CABG surgery from April 2015 to April 2016. The primary outcome was the utilization of secondary prevention GDMT after CABG surgery - aspirin, B-blockers, statin and angiotensin-converting enzyme inhibitors (ACEI) (or angiotensin receptor blockers (ARB) in ACEI-intolerant patients). The proportions of eligible and ideal patients who received treatment were calculated, and mixed-effects logistic regression was used to estimate odds ratios (OR) for the association of age, gender or patient nationality with the use of GDMT. Results: A total number of 119 patients included in the analysis. The median age of the cohort was 57.3 ± 11 years, and 83% were male (83.2%). Nearly 69.7% of patients had diabetes, and 82% had a previous diagnosis of hypertension. Nearly 91% received aspirin therapy and the rate was lower for B-blocker and statin. The rate of GDMT utilization did not change with the change in patient's age, gender or nationality. Conclusion: Despite adjustments for contraindications to GDMT, the rate of GDMT utilization was suboptimal.

A Culture of Early Mobilization in Adult Intensive Care Units: Perspective and Competency of Physicians.

BACKGROUND: Early mobility (EM) is vital in the intensive care unit (ICU) to counteract immobility-related effects. A multidisciplinary approach is key, as it requires precise initiation knowledge. However, physicians' understanding of EM in adult ICU settings remains unexplored. This study was conducted to investigate the knowledge and clinical competency of physicians working in adult ICUs toward EM. METHODS: This cross-sectional study enrolled 236 physicians to assess their knowledge of EM. A rigorously designed survey comprising 30 questions across the demographic, theoretical, and clinical domains was employed. The criteria for knowledge and competency were aligned with the minimum passing score (70%) stipulated for physician licensure by the medical regulatory authority in Saudi Arabia. RESULTS: Nearly 40% of the respondents had more than 5 years of experience. One-third of the respondents received theoretical knowledge about EM as part of their residency training, and only 4% of the respondents attended formal courses to enhance their knowledge. Almost all the respondents (95%) stated their awareness of EM benefits and its indications and contraindications and considered it safe to mobilize patients on mechanical ventilators. However, 62.3% of the respondents did not support EM for critically ill patients on mechanical ventilators until weaning. In contrast, 51.7% of respondents advised EM for agitated patients with RASS > 2. Only 113 (47.9%) physicians were competent in determining the suitability of ICU patients for EM. For critically ill patients who should be mobilized, nearly 60% of physicians refused to initiate EM. CONCLUSIONS: This study underscores insufficient practical knowledge of ICU physicians about EM criteria, which leads to suboptimal decisions, particularly in complex ICU cases. These findings emphasize the need for enhanced training and education of physicians working in adult ICU settings to optimize patient care and outcomes in critical care settings.

In vitro modeling of crimped Dacron vascular grafts for aortic root replacement.

OBJECTIVE: To objectively quantify the effect of flattening the crimps in Dacron tube grafts on the radial compliance under pulsatile pressure. We aimed to minimize the dimensional changes in woven Dacron graft tubes by applying axial stretch to the graft. We hypothesize this might reduce the risk of coronary button misalignment in aortic root replacement. METHODS: In an in vitro pulsatile model that delivered systemic circulatory pressures to Dacron tube grafts, we measured oscillatory movements in 26-30 mm Dacron vascular tube grafts before and after flattening the graft crimps. We also describe our surgical methods and clinical experiences in replacing the aortic root. RESULTS: Flattening the crimps in Dacron tubes with axial stretching significantly reduced the mean maximal oscillation distance measured radially during each balloon pulse (3.2 ± 0.8 mm, 95% CI: 2.6, 3.7 mm vs. 1.5 ± 0.5 mm, 95% CI: 1.2, 1.7 mm; P < 0.001). CONCLUSION: The radial compliance of woven Dacron tubes was significantly reduced after flattening the crimps. Applying axial stretch to the Dacron grafts prior to determining the coronary button attachment site can help maintain dimensional stability in the graft, which may reduce the risk of coronary malperfusion in aortic root replacment.

Impact of Psychological Factors on Functional Performance among Patients with Chronic Obstructive Pulmonary Disease.

The role of anxiety and depression in functional performance during walking in patients with chronic obstructive pulmonary disease (COPD) is controversial. In this cross-sectional study, we aimed to assess the effects of anxiety, depression, and health-related quality of life (HRQOL) on the functional performance of this patient population. Seventy COPD patients aged 63 ± 11 years participated in the study. To measure their functional performance, the six-minute walk test (6MWT) was used. Anxiety and depression were assessed using two questionnaires: the Anxiety Inventory for Respiratory Disease (AIR) scale and the Hospital Anxiety and Depression Scale (HADS). The St. George's Respiratory Questionnaire (SGRQ) was used to assess HRQOL. Based on their anxiety levels, the patients were divided into a no anxiety group and a high anxiety group. There were no significant differences between the two groups in terms of pulmonary function profile or smoking status. The mean AIR and HADS (depression) scores were high (12.78 ± 4.07 and 9.90 ± 3.41, respectively). More than one-third of the patients (46%) reported high anxiety levels (above the standard cutoff score of 8). The mean score of the aggregated HADS scale was significantly higher in the high anxiety group (20.87 ± 6.13) than in the no anxiety group (9.26 ± 4.72; p = 0.01). Patients with high anxiety had poorer functional performance (6MWT: 308.75 ± 120.16 m) and HRQOL (SGRQ: 56.54 ± 22.36) than patients with no anxiety (6MWT: 373.76 ± 106.56 m; SGRQ: 42.90 ± 24.76; p < 0.01). The final multivariate model explained 33% of the variance in functional performance after controlling for COPD severity (F = 8.97). The results suggest that anxiety, depression, and poor health status are significantly associated with poor functional performance. This study highlights the need to screen patients with COPD at all stages for anxiety and depression.

The brain-before-heart strategy for coronary artery bypass grafting in the severely atherosclerotic aorta: A single-institution experience.

BACKGROUND: Severe atherosclerosis of the ascending aorta (SAA) in patients undergoing surgical revascularization by coronary artery bypass grafting (CABG) is becoming an increasing problem as more elderly patients are diagnosed with coronary artery disease. Strokes and other neurologic insults are common complications in this group, with devastating impacts on outcomes and prognoses. HYPOTHESIS: Early detection of the atherosclerotic aorta and the application of a stroke prevention protocol will reduce the risk of stroke in patients with SAA. METHODS: In 2012, we adopted a protocol devised to preemptively detect and manage patients suspected of having SAA. From the time of the application of the protocol, we compared the immediate and late outcomes of CABG in SAA in the 8 years preceding the protocol in a "control" group (30 patients) and in the 8 years following the protocol in a "brain" group (69 patients). RESULTS: More patients with SAA were detected after the initiation of the protocol. They had significantly more history of stroke, renal dysfunction, and left main coronary disease. The percutaneous coronary intervention was utilized more after the protocol (26% vs. 7%) and there was far less utilization of replacement of the ascending aorta (12% vs. 37%). Postoperative stroke rates were significantly less after the protocol (2% vs. 18%), with an almost twofold reduction in stroke associated with SAA even after risk adjustment. The composite endpoints of cardiac death, nonfatal myocardial infarction, and stroke were significantly reduced after initiating the protocol at a median of 2.3 years from the time of revascularization. CONCLUSION: Early detection of SAA and individualized therapeutic strategies for revascularization is effective in reducing athero-embolic brain injury and are associated with better prognosis.

Exercise Capacity Is Independent of Respiratory Muscle Strength in Patients with Chronic Heart Failure.

Background: Exercise intolerance in patients with chronic heart failure (CHF) is associated with a number of factors, including breathlessness and respiratory muscle weakness. However, many studies reported controversial results, and as yet there is no study on Arabic patients with CHF. This study aimed to examine the impact of breathlessness and respiratory muscle strength on exercise capacity in Arabic patients with CHF. Methods: This was a cross-sectional study, involving 42 stable adult male patients with CHF with a reduced ejection fraction and 42 controls who were free from cardiorespiratory and neuromuscular diseases. Patients with CHF and the controls underwent respiratory muscle strength tests and a six-minute walk test (6MWT), and the measurements were taken. Dyspnea was recorded using the modified Medical Research Council (mMRC) scale, along with the number of comorbidities. Results: Patients with CHF and controls were similar in age and sex. Patients with CHF had a greater number of comorbidities, a higher dyspnea score, a lower 6MWT score, and lower respiratory muscle strength (p < 0.001). Only 7% of patients with CHF had weak inspiratory muscle strength (<60% of that predicted) and 40% terminated the 6MWT due to dyspnea. The 6MWT was associated with mMRC (rs = −0.548, p < 0.001) but not with respiratory muscle strength (p > 0.05). Conclusions: Exercise intolerance in patients with CHF was associated with dyspnea and was independent of respiratory muscle strength.

Repair of coronary sinus shear stress injury following blunt chest trauma using adenosine-induced asystole.

Blunt chest trauma following a motor vehicle accident is the leading cause of non-penetrating cardiac injuries. Major structural heart injuries are fatal due to acute tamponade. We present the case of a 17-year-old male who was involved in a motor vehicle accident. He had an isolated coronary sinus rupture, which was successfully repaired. We propose a potential mechanism implicated in this rare injury, and we summarize a novel repair technique with adenosine-induced transient asystole.

Psychometric properties of the Arabic version of the anxiety inventory for respiratory disease in patients with COPD.

PURPOSE: The Anxiety Inventory for Respiratory Disease (AIR) is a reliable and valid scale for examining the anxiety in patients with COPD. This study aimed to cross-culturally adapt and translate the original AIR scale into the Arabic language and to examine its reliability and validity in Arab patients with COPD. MATERIAL AND METHODS: This was a validation study conducted on 70 Arabic patients with COPD. The AIR-A and the Hospital Anxiety and Depression Scale (HADS) were completed on the first assessment. After two weeks, 55 patients completed the AIR-A scale again. The reliability was assessed by Cronbach's α and intraclass correlation coefficients (ICC2,1). Exploratory factor analysis (EFA), and the confirmatory factor analysis (CFA) were used to measure the structural validity. The construct validity was also explored. RESULTS: The AIR-A questionnaire had a Cronbach's α of 0.91 and ICC2,1 of 0.86. The EFA revealed that the AIR-A was unidimensional. The CFA showed the single-factor model required minor modifications to reach the best fit. The AIR-A was correlated with the HADS- anxiety (r = 0.89, p < 0.001). CONCLUSION: The Arabic version of AIR scale is reliable, and valid for assessing the anxiety disorder in Arabic speaking patients with COPD worldwide.Implications for PracticeThe Arabic version of AIR will be useful for examining anxiety in Arabic speaking patients with COPD worldwide.The Arabic version of AIR will help clinicians to monitor the effect of interventions in Arabic speaking patients with COPD who suffer from anxiety.The Arabic version of AIR assess only the anxiety.

Evidence-based clinical practice guidelines for the management of perioperative hypothermia: Systematic review, critical appraisal, and quality assessment with the AGREE II instrument.

Inadvertent perioperative hypothermia is considered an emergency life-threatening situation. Clinical practice guidelines (CPGs) on how to manage hypothermia, based on evidence and expert opinions, could save lives. This systematic review assessed and compared the most recently approved international CPGs with the AGREE II instrument. We searched international bibliographic databases to identify relevant guidelines for managing perioperative hypothermia. Four independent reviewers (consultant anesthesiologists) critically appraised the selected guidelines with the AGREE II instrument. We analyzed inter-rater agreement and calculated an intra-class correlation coefficient (Kappa). We identified five CPGs for perioperative hypothermia that were eligible for critical appraisal. These CPGs were issued by the National Institute for Health and Care Excellence (NICE-2016); the American Society of Peri-Anesthesia Nurses/Agency for Health Care Research and Quality (ASPAN/AHRQ-2006); the University of Southern Mississippi (USM/CPG-2017); The University Assistance Complex of Salamanca (UACS/CPG-2018); and the Justus-Liebig University of Giessen (UKGM/CPG-2015). The overall assessments of NICE-2016 and ASPAN/AHRQ-2006 scored >80%. These results were consistent with high scores achieved in the six domains of AGREE II: (1) scope and purpose, (2) stakeholder involvement, (3) rigor of development, (4) clarity of presentation, (5) applicability, and (6) editorial independence domains. The NICE-2016, ASPAN/AHRQ-2006, and USM/CPG-2017) scored, respectively, 94%, 81%, and 70% for domain 3, 91%, 87%, and 66% for domain 5, and 90%, 82%, and 77% for domain 6. Generally, the NICE CPGs received significantly better clinical recommendations. However, all five evidence-based CPGs were of high methodological quality and were recommended for use in practice. Saudi Arabia should formulate its own national CPGs for diagnosis and management of perioperative hypothermia and to be published on NICE.

Surgical revascularization in stable coronary artery disease with ventricular dysfunction: a single-center cohort study.

PURPOSE: Stress-gated myocardial perfusion scintigraphy (MPS) is used for prognosis in stable coronary artery disease (CAD). We sought to assess coronary artery bypass grafting (CABG) outcomes in stable coronary artery disease patients who had myocardial perfusion scintigraphy and left ventricular (LV) dysfunction. METHODS: Stable CAD patients who underwent CABG (2012-2019) and had stress-gated MPS were identified retrospectively. Based on the post-stress LV ejection fraction, a total of 130 patients were divided into a control group (51%) and LV dysfunction group (49%). RESULTS: Patients with left ventricular dysfunction had significantly more mean summed stress score (22.1 ± 9 Vs. 12.5 ± 8; P ≤ 0.001) and summed resting score (14.6 ± 8 Vs. 3.7 ± 4; P ≤ 0.001) compared to the control group respectively. They also had a greater risk for developing low cardiac output syndrome after surgery (OR: 2.9, 95% CI 1.1-6.6, P=0.033). At 4.7 years, freedom from cardiac death was not statistically significant between the left ventricular dysfunction and control groups, respectively (90.2% vs. 95.6%; P=0.157). Cardiac death was not influenced by either ventricular dysfunction at the time of surgery (HR: 2.6, 95% CI 0.64-10.6, P=0.182) nor by having percent ischemic myocardium > 10% (HR: 0.86, 95% CI 0.23-3.24, P=0.826). CONCLUSION: Significant myocardial ischemia and ventricular dysfunction before complete surgical revascularization did not influence the risk of cardiac-related deaths on long-term follow-up. This might be related to the improved survival after CABG in patients with myocardial ischemia and left ventricular dysfunction.

Atrial septal defect closure in a young patient presenting with recurrent cryptogenic stroke: a case report.

BACKGROUND: Having an inter-atrial shunt in the form of a patent foramen ovale or atrial septal defect increases the risk of developing cryptogenic stroke. Prompt action is required in order to prevent stroke recurrence. The source of embolization may not be clear on stroke workup. CASE PRESENTATION: A young female acutely presented with recurrent embolizations to the eye and brain. She was found to have an atrial septal defect. No clear intra-cardiac source of embolization was detected on workup including trans-esophageal echocardiography. Given the options between surgical versus device closure, the attending team opted for the surgical closure which yielded on direct left heart inspection small organized clots adherent to the tips of the mitral valve leaflets. CONCLUSIONS: The case report illustrates the potential advantages of the direct surgical closure in detecting and extracting the embolization source in patients who present with recurrent cryptogenic stroke.

Spiral aortoplasty for dilated ascending aorta: a new technique for high-risk patients with combined procedures.

Concomitant replacement of the ascending aorta with the aortic valve in patients who have left ventricular dysfunction might carry high operative risks. Performing the conservative reduction aortoplasty was shown to have less complications in such patients. When combined with other concomitant cardiac procedures, the newly described "spiral" aortoplasty technique in this series allows for a mulitplanar wall tension reduction in moderately dilated ascending aorta.

Liver enzyme trends in patients taking uninterrupted metformin before and after coronary surgery.

BACKGROUND: Metformin is an oral antidiabetic agent belonging to the biguanide class of antidiabetics. Possible novel applications for metformin in cardiovascular disease might exist. The aim of this study was to verify a possible association between pre-operative metformin administration and protection against ischemia-induced liver injury in diabetic patients undergoing coronary artery bypass grafting (CABG) surgery. METHODS: A retrospective case-control series was conducted at a single center. Two hundred consecutive diabetic patients underwent isolated on-pump CABG during a 12-month span (July 2015 - July 2016). Metformin was uninterrupted in patients who took this drug prior to CABG; 68 patients were metformin users (34%) while 132 patients were taking other antidiabetic agents (66%). Liver enzymes and other organ markers were consecutively recorded daily for 7 days after surgery and expressed as medians with interquartile range (IQR). RESULTS: Both the metformin and non-metformin group of patients had similar pre-operative demographic characteristics. The median (IQR) post-operative cardiac enzyme creatinine kinase (CK) MB fraction was significantly lower in the metformin group [46.4 U/L (35.8-66.5) vs. 66.5 U/L (44-94.5), P=0.005]. Total bilirubin [0.58 (0.48-0.82) mg/dL vs. 0.67 (0.56-0.95) mg/dL, P=0.021], the transaminase aspartate aminotransferase (AST) [32.5 U/L (25.0-42.0) vs. 37.5 U/L (28.5-56), P=0.011], the transaminases alanine aminotransferase (ALT) [48.5 U/L (40.0-64.0) vs. 57.0 U/L (44.0-77.0), P=0.040] and lactate dehydrogenase (LDH) [320.0 U/L (273.5-367.2) vs. 356.5 U/L (289.5-427), P=0.014] were significantly lower in the metformin group. No differences were noted in clinical outcomes. CONCLUSIONS: In this limited retrospective study, the diabetic patients who took metformin before and after undergoing CABG appeared to have a reduced post-operative surge in the total bilirubin and transaminase liver enzymes. Metformin's role in mitigating oxidative stress in liver cells might explain this observation. Further experimental studies are warranted to verify this possible effect.

Transient liver dysfunction increases surgical site infections after coronary surgery.

Background Surgical site infections can have a significant impact on cardiac surgical outcome. The liver plays an important role in infection prevention. This study aimed to retrospectively determine whether transient postoperative liver dysfunction after coronary bypass surgery increased surgical site infections. Methods A modified version of the Schindl scoring scale for liver dysfunction was adapted to objectively quantify transient liver dysfunction in the first 7 days after on-pump coronary artery bypass grafting. A retrospective analysis of clinical outcomes at 30 months postoperatively was performed on data of 575 patients who underwent coronary artery bypass between 2014 and 2016. The patients were categorized into a liver dysfunction group (Schindl score ≥ 4) and a non-liver dysfunction group (Schindl score < 4). Results The liver dysfunction group (47.3%) had significantly more patients who were obese, current smokers, and had diabetes, renal impairment, and peripheral vascular disease. Surgical site infections occurred predominantly in the liver dysfunction group (12.1% vs. 0.3%, p < 0.001). The independent predictors of surgical site infection were liver dysfunction, body mass index > 30 kg m-2, and coronary bypass surgery combined with other cardiac procedures. Conclusions Surgical wound infections can be precipitated by multiple factors before, during, and after coronary bypass surgery. Transient liver dysfunction in the perioperative period is associated with an increased rate of surgical infections even after adjusting for known risk factors. Considering this factor as well as other known risks may help to identify and stratify patients with a potentially higher risk of surgical site infections.

Effectiveness of Low to Moderate Physical Exercise Training on the Level of Low-Density Lipoproteins: A Systematic Review.

BACKGROUND: Regular exercise reduces risk factors associated with cardiovascular disease (CVD). Elevated low-density lipoprotein (LDL) contributes to atherosclerosis formation, which is associated with an increased risk of CVD. The relationship between exercise therapy and lipid levels has been widely studied, but it is established that high-intensity exercise improves lipid profile. However, the effectiveness of low- to moderate-intensity exercise in altering LDL levels is controversial. This review aims to identify the current evidence and existing gaps in literature in this area. METHODS: We searched and reviewed various randomized controlled clinical trials in the electronic databases EMBASE, CINAHL, the Web of Science, Cochrane, Pedro, Medline (PubMed), and Google Scholar using the keywords "low and moderate aerobic training," "exercise", "low-density lipoproteins," "cholesterol," "atherosclerosis," and "coronary artery diseases markers." We included studies that involved low- and/or moderate-intensity exercise training in apparently healthy adults over a period of 8 weeks and its effect on LDL levels. We selected a total of 11 studies from 469; nine were randomized controlled trials and two were systematic reviews. RESULTS: Aerobic exercise of both low and moderate intensity resulted in a significant reduction of total cholesterol. Effects on low-density lipoprotein levels were significant, and most of the studies showed changes in the level without significant relation to the type of exercise. At the same time, exercise improved the health status and physical fitness of all the participants in the included studies. CONCLUSION: This study found that low- and moderate-intensity exercise and low-density lipoprotein levels were not proven to be significantly related, except in a few studies that were limited to dyslipidemia population.

Outbreak of Middle East Respiratory Syndrome-Coronavirus Causes High Fatality After Cardiac Operations.

Middle East respiratory syndrome-coronavirus (MERS-CoV) resembles a severe form of community-acquired pneumonia initially reported in Saudi Arabia in 2012. The MERS-CoV epidemic poses a big challenge because of its high mortality. In January 2015, a patient who was potentially incubating MERS-CoV arrived from the emergency department of another hospital and was admitted with acute coronary syndrome. This resulted in an outbreak in the cardiac surgery ward that caused the deaths of 5 of 6 patients who had undergone cardiac operations.

Metformin is not associated with lactic acidosis in patients with diabetes undergoing coronary artery bypass graft surgery: a case control study.

BACKGROUND: Metformin associated lactic acidosis (MALA) is a rare but lethal complication. There is no consensus regarding when to stop and resume metformin in patients who undergo coronary artery bypass grafting (CABG). This study aimed to determine if uninterrupted metformin administration in patients with diabetes undergoing CABG increases the risk of lactic acidosis. METHODS: Over a span of 12 months (2015-2016), 127 patients with type 2 diabetes underwent isolated CABG. Of those, 41 patients (32%) continued taking metformin and 86 patients (68%) took other antidiabetic agents. Patients taking metformin took the drug until the day of surgery and resumed taking it 3 h after extubation. RESULTS: There were no differences in clinical outcomes or complications between groups. Serial measurement of cardiac, liver, and kidney biomarkers were similar between groups. The mean peak lactic acid level was significantly higher in the non-metformin users (5.4 ± 2.6 vs. 7.4 ± 4.1 mmol/l; P = 0.001). Multivariable logistic regression analysis identified the need for vasopressor administration as an independent predictor of lactic acidosis (odds ratio: 7.3, 95% confidence interval: 2.5-20.6; P < 0.001). CONCLUSION: In the absence of risk factors associated with persistent lactic acidosis, such as shock or acute kidney or liver injury, continued peri-operative metformin administration was not associated with the occurrence of lactic acidosis in patients undergoing CABG. Elevated lactic acid levels seem to be directly related to tissue anoxia caused by escalating vasopressor support after surgery.

The influence of operative techniques on the outcomes of bicuspid aortic valve disease and aortic dilatation.

BACKGROUND: Bicuspid aortic valve is associated with aortic aneurysm formation that may extend beyond the ascending aorta. METHODS: Between 1979 and 1997, 143 bicuspid aortic valve patients had aortic valve operations with replacement of an aneurysmal ascending aorta: 93 (65%) underwent full root replacement and 50 (35%) underwent separate valve and graft replacement. Distal aortic anastomosis was open in 42 patients (29%) and closed in 101 (71%). Late survival and complications were compared by surgical technique. RESULTS: Patients undergoing full root replacement tended to be younger (mean age 46 +/- 16 vs 59 +/- 13, p < 0.001) and presented with more aortic insufficiency (80% vs 35%, p < 0.001). Three (2.1%) hospital deaths occurred. Event-free survival was 82% (95% confidence interval, 75% to 88%) at 10 years and 41% (95% confidence interval, 11% to 71%) at 20 years. At a median follow-up of 11.5 years, the incidence of new aneurysms and late aortic complications were not significantly different among the procedure groups. Age at the time of operation was the only predictor of late survival (hazard ratio, 1.07; p = 0.007). CONCLUSIONS: Aortic root replacement with distal aortic reconstruction can be achieved with very low operative mortality and excellent long-term outcomes in patients with bicuspid aortic valve and dilated ascending aorta. The type of surgical procedure done in the aortic root and in the distal ascending aorta does not influence late survival, subsequent operation, or aortic complications. This is likely influenced by our patient-specific strategy when replacing the aortic root and distal ascending aorta.