A quantitative evaluation of aerosol generation during cardiopulmonary resuscitation.

It is unclear if cardiopulmonary resuscitation is an aerosol-generating procedure and whether this poses a risk of airborne disease transmission to healthcare workers and bystanders. Use of airborne transmission precautions during cardiopulmonary resuscitation may confer rescuer protection but risks patient harm due to delays in commencing treatment. To quantify the risk of respiratory aerosol generation during cardiopulmonary resuscitation in humans, we conducted an aerosol monitoring study during out-of-hospital cardiac arrests. Exhaled aerosol was recorded using an optical particle sizer spectrometer connected to the breathing system. Aerosol produced during resuscitation was compared with that produced by control participants under general anaesthesia ventilated with an equivalent respiratory pattern to cardiopulmonary resuscitation. A porcine cardiac arrest model was used to determine the independent contributions of ventilatory breaths, chest compressions and external cardiac defibrillation to aerosol generation. Time-series analysis of participants with cardiac arrest (n = 18) demonstrated a repeating waveform of respiratory aerosol that mapped to specific components of resuscitation. Very high peak aerosol concentrations were generated during ventilation of participants with cardiac arrest with median (IQR [range]) 17,926 (5546-59,209 [1523-242,648]) particles.l-1 , which were 24-fold greater than in control participants under general anaesthesia (744 (309-2106 [23-9099]) particles.l-1 , p < 0.001, n = 16). A substantial rise in aerosol also occurred with cardiac defibrillation and chest compressions. In a complimentary porcine model of cardiac arrest, aerosol recordings showed a strikingly similar profile to the human data. Time-averaged aerosol concentrations during ventilation were approximately 270-fold higher than before cardiac arrest (19,410 (2307-41,017 [104-136,025]) vs. 72 (41-136 [23-268]) particles.l-1 , p = 0.008). The porcine model also confirmed that both defibrillation and chest compressions generate high concentrations of aerosol independent of, but synergistic with, ventilation. In conclusion, multiple components of cardiopulmonary resuscitation generate high concentrations of respiratory aerosol. We recommend that airborne transmission precautions are warranted in the setting of high-risk pathogens, until the airway is secured with an airway device and breathing system with a filter.

Acute regional changes in myocardial strain may predict ventricular remodelling after myocardial infarction in a large animal model.

To identify predictors of left ventricular remodelling (LVR) post-myocardial infarction (MI) and related molecular signatures, a porcine model of closed-chest balloon MI was used along with serial cardiac magnetic resonance imaging (CMRI) up to 5-6 weeks post-MI. Changes in myocardial strain and strain rates were derived from CMRI data. Tissue proteomics was compared between infarcted and non-infarcted territories. Peak values of left ventricular (LV) apical circumferential strain (ACS) changed over time together with peak global circumferential strain (GCS) while peak GLS epicardial strains or strain rates did not change over time. Early LVR post-MI enhanced abundance of 39 proteins in infarcted LV territories, 21 of which correlated with LV equatorial circumferential strain rate. The strongest associations were observed for D-3-phosphoglycerate dehydrogenase (D-3PGDH), cysteine and glycine-rich protein-2, and secreted frizzled-related protein 1 (sFRP1). This study shows that early changes in regional peak ACS persist at 5-6 weeks post-MI, when early LVR is observed along with increased tissue levels of D-3PGDH and sFRP1. More studies are needed to ascertain if the observed increase in tissue levels of D-3PGDH and sFRP1 might be casually involved in the pathogenesis of adverse LV remodelling.

Inflammation, oxidative stress and postoperative atrial fibrillation in cardiac surgery.

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery that occurs in up to 60% of patients. POAF is associated with increased risk of cardiovascular mortality, stroke and other arrhythmias that can impact on early and long term clinical outcomes and health economics. Many factors such as disease-induced cardiac remodelling, operative trauma, changes in atrial pressure and chemical stimulation and reflex sympathetic/parasympathetic activation have been implicated in the development of POAF. There is mounting evidence to support a major role for inflammation and oxidative stress in the pathogenesis of POAF. Both are consequences of using cardiopulmonary bypass and reperfusion following ischaemic cardioplegic arrest. Subsequently, several anti-inflammatory and antioxidant drugs have been tested in an attempt to reduce the incidence of POAF. However, prevention remains suboptimal and thus far none of the tested drugs has provided sufficient efficacy to be widely introduced in clinical practice. A better understanding of the cellular and molecular mechanisms responsible for the onset and persistence of POAF is needed to develop more effective prediction and interventions.

The competent isolated double orifice mitral valve: an incidental finding during excision of a papillary fibroelastoma.

The double orifice mitral valve is associated with a number of congenital abnormalities and comprises two mitral orifices separated by an accessory bridge of fibrous tissue and surrounded by a single fibrous annulus. We present our management of a case of a double orifice mitral valve associated with a papillary fibroelastoma.

Body dissatisfaction, abnormal eating behaviours and eating disorder attitude in homo- and heterosexuals.

OBJECTIVE: The primary aim of this study was to investigate the relationship between sexual orientation and disordered eating attitudes and behaviours in a sample of homosexuals and heterosexuals subject. METHODS: We screened 110 homosexuals (85 males and 25 females) and 121 heterosexuals (85 males and 36 females) by means of: a) an ad hoc socio-demographic schedule; b) the Eating Disorders Inventory 2 (EDI 2); the Eating Disorders Inventory 2 - Symptom Checklist (EDI-SC); the Body Uneasiness Test (BUT). RESULTS: Male homosexuals obtained much higher scores than male heterosexuals on the EDI 2 Drive for thinness, Bulimia, Ineffectiveness, Interoceptive awareness, Impulse regulation scales and on all the BUT subscales. Similarly, with regard to eating behaviours, a significantly higher frequency in the use of strategies to compensate weight increase was observed. On all these scales the sample of homosexual males did not show any significant differences from the group of hetero- and homosexual women. The male homosexuals who claimed they were not in a stable relationship scored higher in all the variables considered. DISCUSSION: Our findings seem to suggest that homosexual orientation is associated with greater body dissatisfaction and abnormal eating behaviours in males, in particular among those who claimed they were not in a sentimental relationship.

The importance of myocardial amino acids during ischemia and reperfusion in dilated left ventricle of patients with degenerative mitral valve disease.

Taurine, glutamine, glutamate, aspartate, and alanine are the most abundant intracellular free amino acids in human heart. The myocardial concentration of these amino acids changes during ischemia and reperfusion due to alterations in metabolic and ionic homeostasis. We hypothesized that dilated left ventricle secondary to mitral valve disease has different levels of amino acids compared to the right ventricle and that such differences determine the extent of amino acids' changes during ischemia and reperfusion. Myocardial concentration of amino acids was measured in biopsies collected from left and right ventricles before cardioplegic arrest (Custodiol HTK) and 10 min after reperfusion in patients undergoing mitral valve surgery. The dilated left ventricle had markedly higher (P < 0.05) concentrations (nmol/mg wet weight) of taurine (17.0 +/- 1.5 vs. 10.9 +/- 1.5), glutamine (20.5 +/- 2.4 vs. 12.1 +/- 1.2), and glutamate (18.3 +/- 2.2 vs. 11.4 +/- 1.5) when compared to right ventricle. There were no differences in the basal levels of alanine or aspartate. Upon reperfusion, a significant (P < 0.05) fall in taurine and glutamine was seen only in the left ventricle. These changes are likely to be due to transport (taurine) and/or metabolism (glutamine). There was a marked increase in the alanine to glutamate ratio in both ventricles indicative of ischemic stress which was confirmed by global release of lactate during reperfusion. This study shows that in contrast to the right ventricle, the dilated left ventricle had remodeled to accumulate amino acids which are used during ischemia and reperfusion. Whether these changes reflect differences in degree of cardioplegic protection between the two ventricles remain to be investigated.

Inadequate blood glucose control is associated with in-hospital mortality and morbidity in diabetic and nondiabetic patients undergoing cardiac surgery.

BACKGROUND: Derangement of glucose metabolism after surgery is not specific to patients with diabetes mellitus. We investigated the effect of different degrees of blood glucose control (BGC) on clinical outcomes after cardiac surgery. METHODS AND RESULTS: We analyzed 8727 adults operated on between April 1996 and March 2004. The highest blood glucose level recorded over the first 60 hours postoperatively was used to classify patients as having good (<200 mg/dL), moderate (200 to 250 mg/dL), or poor (>250 mg/dL) BGC; 7547 patients (85%) had good, 905 (10%) had moderate, and 365 (4%) had poor BGC. Patients with inadequate BGC were more likely to present with advanced New York Heart Association class, congestive heart failure, hypertension, renal dysfunction, and ejection fraction <50% (P0

Mechanical heart valves in septuagenarians.

AIM: To report on the use of a third-generation bileaflet mechanical valve in septuagenarians, selected to receive a mechanical valve, as compared to (a) a younger cohort undergoing same valve implant (study 1) and to (b) a matched group of septuagenarians undergoing biological implant (study 2). METHODS: The study was carried out in a tertiary regional hospital in South-West England. Study 1: Consecutive series of 567 patients undergoing Sorin Bileaflet (SB) mechanical valve implant (437 patients < 70 years; 130 patients >or= 70 years). Study 2: 113 septuagenarians undergoing biological implant matched on age, valve type, concomitant coronary surgery, and operative priority to the SB septuagenarian group. Main outcome measures included in-hospital mortality and morbidity and mid-term valve-related outcome. RESULTS: Study 1: Septuagenarians were more likely to present with coronary disease, and to undergo coronary surgery (p < 0.01). In-hospital mortality was 2.8% and 2.3% (p = 0.79) and neurological complications 1.4% versus 3.8% (p = 0.026) in the younger and older groups, respectively. Valve-related mortality at two years was 1.8% (95%CI, 0.8% to 3.6%) and 4.8% (95% CI, 2.0% to 9.7%); cumulative three- year incidence of thromboembolic or major hemorrhagic event was 8.3% (95% CI, 5.7% to 12.0%) and 4.6% (95% CI, 1.7% to 12.4%) in the younger and older groups, respectively. Study 2: In-hospital mortality was 1.8% and 7.1% in the SB and biological groups, respectively (ratio 0.25; 95% CI, 0.05 to 1.18, p = 0.058). The incidence of acute renal failure was greater in the biological group (risk ratio 0.30; 95% CI, 0.09 to 0.98, p = 0.035). There was no difference in mid-term valve-related mortality between groups (hazard ratio 0.53; 95% CI, 0.18 to 1.52, p = 0.24). CONCLUSION: The performance of SB valve in septuagenarians seems to be effective with no increased risk of in-hospital mortality, bleeding, or thromboembolic events.

Risk factors for and economic implications of prolonged ventilation after cardiac surgery.

OBJECTIVE: The study's objective was to identify predictors of prolonged ventilation and assess clinical and cost implications in patients undergoing cardiac surgery. METHODS: Patients undergoing cardiac surgery were classified as (1) ventilated less than 96 hours or (2) ventilated 96 hours or more. Multivariate modeling was used to identify predictors of prolonged ventilation and to ascertain the impact of prolonged ventilation on in-hospital mortality and bed occupancy costs and 5-year survival. RESULTS: A total of 7553 patients were studied; 197 (2.6%) had prolonged ventilation. Median ventilation times were 8 and 192 hours, and in-hospital mortality was 1.0% and 22.2% in the control and prolonged ventilation groups, respectively (P < .001). In-hospital mortality remained higher in the prolonged ventilation group after adjustment and when comparing propensity-matched patients (odds ratio 8.06; 95% confidence interval [CI] 4.27-15.2; P < .001 for propensity-matched groups). Independent predictors of prolonged ventilation were as follows: older age, New York Heart Association class, ejection fraction less than 50%, creatinine greater than 200 micromol/L, multiple valve replacements, aortic procedures, operative priority, reoperation for bleeding, inotropes, and preoperative intra-aortic balloon pump. Five-year survival was lower in the prolonged ventilation group (56.1% [95% CI 46.6%-64.6%] vs 88.8% [95% CI 87.9%-89.6%]) also after adjustment for imbalances and when comparing propensity-matched patients (hazard ratio 2.39; 95% CI 1.75-3.27; P < .001 for propensity-matched groups). Mean bed occupancy costs were 14,286 dollars (95% CI 12,731 dollars-15,690 dollars) and 2761 dollars (95% CI 2705 dollars-2814 dollars) in the prolonged ventilation and control groups, respectively (P < .001). CONCLUSION: Prolonged ventilation is associated with high in-hospital mortality and costs, and poor 5-year survival. Identified predictors of prolonged ventilation might help to optimize the clinical management of these patients.

Operative factors that contribute to post-operative atrial fibrillation: insights from a prospective randomized trial.

Atrial fibrillation (AF) is the most common complication following cardiac surgery and is associated with significant increases in postoperative morbidity, length of stay and cost of care. In a randomized study we assessed the impact of coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) (off-pump, n = 100), compared to conventional (on-pump, n = 100) CABG, on the frequency of postoperative AF. Arrhythmias were detected using an automated arrhythmia detector for the first 72 hours following surgery and by four hourly clinical observations thereafter. AF was defined as an irregular narrow complex rhythm (in the absence of bundle branch block) with absence of discrete P waves lasting greater then 10 minutes. There was a significant reduction in the incidence of postoperative AF in the off-pump group (11% versus 45%, P < 0.001) in addition to significant reductions in blood usage, postoperative pneumonia, inotrope requirements, and hospital and intensive care unit stay. Univariate analysis identified all these variables as risk factors for AF, however multivariate regression analysis identified CPB and cardioplegic arrest as the only independent predictor of postoperative AF (OR 7.4; 95% CI 3.4 to 17.9). This study therefore suggests that the inflammatory response to bypass, myocardial ischaemia and atrial cannulation are significant contributory factors to the development of AF following cardiac surgery. In the light of more recent trials it is apparent that this benefit may be most marked in patients with multiple perioperative risk factors for postoperative AF.

Socioeconomic deprivation is a predictor of poor postoperative cardiovascular outcomes in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To investigate the effects of socioeconomic deprivation on cardiovascular risk factors and postoperative clinical outcomes of patients undergoing coronary artery bypass grafting (CABG). DESIGN: Retrospective analysis of prospectively collected data. SETTING: Surgical population of the southwest of England, April 1996 and August 2000. STUDY GROUP: Data on 3578 consecutive patients undergoing CABG at the Bristol Royal Infirmary NHS Trust were abstracted. Data were retrieved from the Patient Analysis & Tracking System. Carstairs index was used to measure socioeconomic deprivation of area of residence and was divided into five quintiles, where quintile 1 denotes least deprived and 5 most deprived. OUTCOME MEASURES: End points were postoperative complications and 30 day mortality. RESULTS: Higher deprivation scores were associated with younger age (p < 0.004), greater body mass index, diabetes, smoking at time of surgery, and higher EuroSCOREs (all p < or = 0.001). After adjustment for EuroSCORE, socioeconomic deprivation was independently associated with postoperative myocardial infarction (p = 0.05) and combined postoperative myocardial infarction, stroke, and death (p = 0.016). Hospital length of stay for the patients in the highest quintiles was also significantly longer than for those in the lower quintiles (p = 0.04). CONCLUSION: Patients undergoing CABG living in areas with high deprivation scores are younger, have more clinical risk factors, and experience more postoperative cardiovascular complications than patients living in low deprivation score areas.

Coronary artery bypass grafting in patients over 70 years old: the influence of age and surgical technique on early and mid-term clinical outcomes.

OBJECTIVE: To investigate the influence of age and modern techniques of coronary artery bypass grafting with or without cardiopulmonary bypass on early and mid-term mortality and morbidity in a consecutive series of elderly patients. METHODS: From April 1996 to December 2000, data of 3842 patients undergoing coronary revascularisation were prospectively entered into a database. Data were extracted for 990 patients older than 70 years: (A) 70-74 years, (n=659); (B) 75 or more years, (n=331). RESULTS: A total of 990 elderly patients (> or = 70 years) underwent coronary revascularisation, 219 (22.1%) with off-pump surgery. Elderly patients were more likely to have higher CCS, NYHA and EuroScores, history of previous MI, unstable angina, renal dysfunction, left main stem disease > or = 50%, and to be urgent. However, they were less likely to be overweight. In-hospital mortality, occurrence of re-intubation, renal dysfunction, and hospital stay were significantly higher in this elderly group. Overall, the distribution of mortality was doubled in the female gender although this was not statistically significant. Patients undergoing on-pump surgery had lower EuroScore, were less likely to be >75 years of age, likely to have obesity or hypercholesterolaemia, or to have suffered a previous cerebro-vascular accident. However, they had more extensive coronary disease, were more likely to have unstable angina, and received more grafts than those undergoing off-pump surgery. After adjustment for prognostic variables, off-pump surgery was found to be associated with reduced inotropic use, intra-operative arrhythmias, blood loss and transfusion requirement when compared to on-pump coronary surgery (point estimates of odd ratios, 0.26-0.87) (all P<0.05). Mid-term mortality or cardiac-related events were similar in the two groups. CONCLUSIONS: Early but not mid-term mortality is higher in patients aged 75 or more years when compared with those aged 70-74 years. Off-pump coronary artery bypass surgery is safe and effective in the elderly population.

Detection of postoperative pseudoaneurysms following abdominal aortic aneurysm repair in Behçet's disease by MRA.

We report the development of two anastomotic pseudoaneurysms in a patient with Behçet's disease eighteen months after abdominal aortic aneurysm repair. Major asymptomatic vascular complications should be suspected in patients with Behçet's disease with a history of vascular surgery and treated expediently due to the risk of rupture. Magnetic resonance angiography, contrast-enhanced computed tomography or ultrasound scanning should be performed at least every 6 months after vascular surgery.

Myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using cold or warm blood cardioplegia.

OBJECTIVES: Myocardial protection techniques during cardiac surgery have been largely investigated in the clinical setting of coronary revascularisation. Few studies have been carried out on patients with left ventricular hypertrophy where the choice of delivery, and temperature of cardioplegia remain controversial. This study investigates metabolic changes and myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using antegrade cold or warm blood cardioplegia. METHODS: Thirty-five patients were prospectively randomised to intermittent antegrade cold or warm blood cardioplegia. Left ventricular biopsies were collected at 5min following institution of cardiopulmonary bypass, 30min after cross-clamping the aorta and 20min after cross-clamp removal, and used to determine metabolic changes during surgery. Metabolites (adenine nucleotides, amino acids and lactate) were measured using high pressure liquid chromatography and enzymatic techniques. Postoperative myocardial troponin I release was used as a marker of myocardial injury. RESULTS: Ischaemic arrest was associated with significant increase in lactate and alanine/glutamate ratio only in the warm blood group. During reperfusion, alanine/glutamate ratio was higher than preischaemic levels in both groups, but the extent of the increase was considerably greater in the warm blood group. Troponin I release was markedly (P<0.05, Mean+/-SD) lower at 1, 24 and 48h postoperatively in the cold compared to the warm blood group (0.51+/-0.37, 0.37+/-0.22 and 0.27+/-0.19 vs. 0.75+/-0.42, 0.73+/-0.51 and 0.54+/-0.38ng/ml for cold vs. warm group, respectively). CONCLUSIONS: Cold blood cardioplegia is associated with less ischaemic stress and myocardial injury compared to warm blood cardioplegia in patients with aortic stenosis undergoing valve replacement surgery. Both cardioplegic techniques, however, confer sub-optimal myocardial protection.

One-stage coronary and abdominal aortic operation with or without cardiopulmonary bypass: early and midterm follow-up.

BACKGROUND: The aim of this study was to compare hospital, early, and late clinical outcomes for patients undergoing one-stage, coronary and abdominal aortic surgical intervention with and without cardiopulmonary bypass. METHODS: From March 1990 to September 1999, 42 consecutive patients underwent combined operations at a single institution. Cardiopulmonary bypass and cardioplegic arrest were used during coronary revascularization in the first 20 patients (on-pump group), and the next 22 patients received the one-stage operations on the beating heart (off-pump group). RESULTS: Baseline characteristics were similar between groups. Three cardiac-related hospital deaths occurred in the on-pump group and one such death in the off-pump group (p = 0.25). Cardiac-related events, pulmonary complications, inotropic support, blood loss and transfusion requirements, intensive care unit stay, and hospital stay were significantly reduced in the off-pump group (all, p < 0.05). The actuarial survival rates in the on-pump and off-pump groups were 80% and 95%, respectively, at 1 year (p = 0.13) and 75% and 89%, respectively, at 3 years (p = 0.22). Freedom from cardiac-related events at 1-year follow-up was 91% in the off-pump group and 65% in the on-pump group (p < 0.05). No difference in cardiac-related events between groups was observed at 3 years. CONCLUSIONS: Off-pump coronary surgical procedures decrease postoperative complications in high-risk patients undergoing simultaneous coronary and abdominal aortic operations compared with the conventional one-stage procedure. The early benefits achieved with off-pump surgical intervention are not at the expense of the long-term clinical outcome.

Clinical and angiographic outcome of different surgical strategies of bilateral internal mammary artery grafting.

Long-term survival, relief of angina, and prevention of myocardial infarction after coronary revascularization are related to the preoperative status of the patient, progression of coronary artery atherosclerosis, and the patency of the conduits used. The increased use of the internal mammary artery for coronary grafting depends upon the accumulation of data on superior late patency compared with venous conduits. These data have supported the simultaneous use of both left and right internal mammary arteries with reported improved late survival. However, controversy still surrounds the clinical and angiographic outcomes of some of the surgical strategies of bilateral internal mammary artery grafting. This review examines a range of surgical strategies of bilateral internal mammary artery grafting and their mid- and long-term clinical and angiographic outcomes. From the available data, careful preoperative selection of patients is paramount. Clinical and angiographic outcome of bilateral internal mammary grafting is superior to single internal mammary grafting with supplemental vein grafts when pedicled, sequential, or free aorto-coronary internal mammary artery is used. Further studies are needed to evaluate the midterm and long-term clinical and angiographic outcomes of complex strategies such as Y or T procedures.