Effects of body size on operative, intermediate, and long-term outcomes after coronary artery bypass operation

Predictive role of cardiopulmonary bypass exposure indexed to body surface area on postoperative organ dysfunction: a retrospective cohort study

OBJECTIVES

Long cardiopulmonary bypass times are associated with adverse postoperative outcomes and increased healthcare resource use. It is likely that this effect is pronounced in smaller patients. Previous studies have been criticized for not taking into consideration that prolonged bypass times are often due to higher complexity. The purpose of this study was to investigate the relationship between bypass index (bypass time/body surface area) and adverse postoperative events.

METHODS

Single-centre, retrospective cohort study including 2413 patients undergoing cardiac surgery on cardiopulmonary bypass from June 2018 to April 2020. Length of hospital stay, as surrogate marker of postoperative morbidity, was selected as primary outcome. The strength of association between bypass index and the primary outcome was assessed with linear regression analysis. Secondary outcomes included new onset renal, pulmonary or cardiac rhythm dysfunction. The predictive value of bypass index was assessed with linear regression analysis; univariate and multiple regression were used to assess the strength of association between Bi and the secondary outcomes.

RESULTS

Bypass index was predictive for length of stay at univariate (Relative Risk (RR): 1.004, P < 0.001) and at multivariable (RR: 1.003, P < 0.001) analysis. The association between bypass index and new renal (mean difference: 14.1 min/m2, P < 0.001) and cardiac rhythm dysfunction (mean difference: 12.6 min/m2) was significant. This was not true of postoperative lung dysfunction (mean difference: -1.5 min/m2, P = 0.293).

CONCLUSIONS

Bypass index, calculated as total bypass time/patient body surface area, is predictive of postoperative morbidity and resource utilization after cardiac surgery on pump.

Intraoperative Anemia Mediates Sex Disparity in Operative Mortality After Coronary Artery Bypass Grafting

BACKGROUND

Women undergoing coronary artery bypass grafting (CABG) have higher operative mortality than men.

OBJECTIVES

The purpose of this study was to evaluate the relationship between intraoperative anemia (nadir intraoperative hematocrit), CABG operative mortality, and sex.

METHODS

This was a cohort study of 1,434,225 isolated primary CABG patients (344,357 women) from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (2011-2022). The primary outcome was operative mortality. The attributable risk (AR) (the risk-adjusted strength of the association of female sex with CABG outcomes) for the primary outcome was calculated. Causal mediation analysis derived the total effect of female sex on operative mortality risk and the proportion of that effect mediated by intraoperative anemia.

RESULTS

Women had lower median nadir intraoperative hematocrit (22.0% [Q1-Q3: 20.0%-25.0%] vs 27.0% [Q1-Q3: 24.0%-30.0%], standardized mean difference 97.0%) than men. Women had higher operative mortality than men (2.8% vs 1.7%; P < 0.001; adjusted OR: 1.36; 95% CI: 1.30-1.41). The AR of female sex for operative mortality was 1.21 (95% CI: 1.17-1.24). After adjusting for nadir intraoperative hematocrit, AR was reduced by 43% (1.12; 95% CI: 1.09-1.16). Intraoperative anemia mediated 38.5% of the increased mortality risk associated with female sex (95% CI: 32.3%-44.7%). Spline regression showed a stronger association between operative mortality and nadir intraoperative hematocrit at hematocrit values <22.0% (P < 0.001).

CONCLUSIONS

The association of female sex with increased CABG operative mortality is mediated to a large extent by intraoperative anemia. Avoiding nadir intraoperative hematocrit values below 22.0% may reduce sex differences in CABG operative mortality.

The effects of a structured physiotherapy program on pulmonary function and walking capacity in obese and non-obese adults undergoing cardiac surgery

BACKGROUND: Obesity is thought to be a risk factor for cardiopulmonary diseases due to changed pulmonary mechanics. It also drastically lowers functional capability in both males and females. A routine physiotherapy program has been shown to be effective in the prevention and treatment of cardiopulmonary diseases. It also significantly increases functional capacity following coronary artery bypass grafting. However, the effect of a structured physiotherapy program in obese and non-obese patients has not been well explored. As such, the objective of this study is to determine the effect of a standardized physiotherapy program on pulmonary function and walking capacity in obese and non-obese patients undergoing coronary artery bypass grafting. METHODS: A prospective study was conducted on 50 obese (age 57.2 ± 6.3 Y) and non-obese (age 56.6 ± 5.7 Y) adults who were schedule for coronary artery bypass grafting. Their body mass index was used to separate them into two groups. Both groups followed a structured physiotherapy program from day 1 to day 7 post cardiac surgery. Both groups underwent spirometry test at baseline (preoperatively) and after day 4 and day 7 postoperatively as well as a six-minute walk test at baseline and on day 7 postoperatively. RESULTS: At baseline, obese individuals had significantly lower pulmonary and physical functioning. On postoperative day 4, both groups deteriorated, although the obese group deterioration was worse, in most of the pulmonary parameters. On postoperative day 7, both groups improved, though the non-obese group improved at a faster rate. In contrary, it was observed that the obese group improved more rapidly in terms of functional capacity. CONCLUSIONS: The study indicated that the outcomes of a structured physiotherapy program following coronary artery bypass grafting were different for persons who were obese compared to those who were not. Adipose tissue variations surrounding the rib cage, diaphragm, and visceral cavity may account for the observed rate of change between the two groups. Therefore, it is apparent that a new strategy for managing obese individuals who have undergone CABG is required.

Impact of Obesity on Early In-Hospital Outcomes after Coronary Artery Bypass Grafting Surgery in Acute Coronary Syndrome: A Propensity Score Matching Analysis

Recent advances in perioperative care have considerably improved outcomes after coronary artery bypass graft (CABG) surgery. However, obesity can increase postoperative complication rates and can lead to increased morbidity and mortality. Between June 2011 and October 2019, a total of 1375 patients with acute coronary syndrome (ACS) underwent cardiac surgery and were retrospectively analyzed. Patients were divided into 2 groups: non-obese (body mass index (BMI) < 30 kg/m2, n = 967) and obese (BMI ≥ 30 kg/m2, n = 379). Underweight patients (n = 29) were excluded from the analysis. To compare the unequal patient groups, a propensity score-based matching (PSM) was applied (non-obese group (n = 372) vs. obese group (n = 372)). The mean age of the mentioned groups was 67 ± 10 (non-obese group) vs. 66 ± 10 (obese group) years, p = 0.724. All-cause in-hospital mortality did not significantly differ between the groups before PSM (p = 0.566) and after PSM (p = 0.780). The median length of ICU (p = 0.306 before PSM and p = 0.538 after PSM) and hospital stay (p = 0.795 before PSM and p = 0.131 after PSM) was not significantly higher in the obese group compared with the non-obese group. No significant differences regarding further postoperative parameters were observed between the unadjusted and the adjusted group. Obesity does not predict increased all-cause in-hospital mortality in patients undergoing CABG procedure. Therefore, CABG is a safe procedure for overweight patients.

The association between different body mass index levels and midterm surgical revascularization outcomes

Background

There are conflicting results regarding the relationship between overweight/obesity and the outcomes of coronary artery bypass graft surgery (CABG), termed “the obesity paradox”. This study aimed to evaluate the effects of body mass index (BMI) on the midterm outcomes of CABG.

Methods

This historical cohort study included all patients who underwent isolated CABG at our center between 2007 and 2016. The patients were divided into five categories based on their preoperative BMIs (kg/m²): 18.5≤BMI<25, 25≤BMI<30, 30≤BMI<35, 35≤BMI<40, and BMI≥40. Patients with BMIs below 18.5 kg/m² were excluded. The endpoints of this study were all-cause mortality and major adverse cardio-cerebrovascular events (MACCEs), comprising acute coronary syndromes, cerebrovascular accidents, and all-cause mortality at five years. For the assessment of the linearity of the relationship between continuous BMI and the outcomes, plots for time varying hazard ratio of BMI with outcomes were provided.

Results

Of 17 751 patients (BMI = 27.30 ±4.17 kg/m²) who underwent isolated CABG at our center, 17 602 patients (mean age = 61.16±9.47 y, 75.4% male) were included in this study. Multivariable analysis demonstrated that patients with pre-obesity and normal weight had similar outcomes, whereas patients with preoperative BMIs exceeding 30 kg/m² kg/m² had a significantly higher risk of 5-year all-cause mortality and 5-year MACCEs than those with pre-obesity. Additionally, a positive association existed between obesity degree and all-cause mortality and MACCEs. Further, BMIs of 40 kg/m² or higher showed a trend toward higher MACCE risks (adjusted hazard ratio, 1.32; 95% confidence interval, 0.89 to 1.95), possibly due to the small sample size. A nonlinear, albeit negligible, association was also found between continuous BMI and the study endpoints.

Conclusions

Our findings suggest that preoperative obesity (BMI>30 kg/m²) in patients who survive early after CABG is associated with an increased risk of 5-year all-cause mortality and 5-year MACCEs. These findings indicate that physicians and cardiac surgeons should encourage patients with high BMIs to reduce weight for risk modification.

Impact of gender differences on hemostasis in patients after coronary artery bypass grafts surgeries in the context of tranexamic acid administration

BACKGROUND

Sex differences present in the blood management of patients after coronary artery bypass grafts (CABG) surgeries. Tranexamic acid (TXA) performed well in maintaining hemostasis during and after surgeries. However, the impact of sex differences on blood control after CABG in patients who received TXA was not investigated.

METHODS

Overall, 29,536 patients undergoing CABG with TXA administration from 2009 to 2019 in our hospital were included. Propensity score matching was performed. Finally, 6808 males and 6808 females were matched based on 23 covariates.

RESULTS

Female patients had a 0.36-fold lower incidence of reoperations due to major hemorrhage or cardiac tamponade compared to males (1.3% vs. 2.0%, p = 0.001, OR = 0.64, 95%CI = 0.49-0.84). Females had a median of 100 ml less blood loss in 24 h (median 360 vs. 460 ml, p < 0.0001), 150 ml less in 48 h (median 580 vs. 730 ml, p < 0.0001), and 180 ml less in total (median 760 vs. 940 ml, p < 0.0001) than male patients. The red blood cell (RBC) transfusion rate in female was 1.53-fold higher than that in male (33.0% vs. 21.6%, OR = 1.53, 95% CI = 1.43-1.63, p < 0.0001). Females also had higher morbidities than males after CABGs.

CONCLUSIONS

Females had less blood loss than males after CABG with the TXA treatment. Females still had a higher RBC transfusion rate after surgery. Morbidities in women were also higher than that in men.

Does a Small Body Have a Negative Impact on Minimally Invasive Mitral Valve Surgery?

Backgrounds

Minimally invasive mitral valve surgery (MIMVS) in patients with a small body presents surgeons with a technically difficult surgical maneuver. We hypothesized that physique might negatively influence the safety and technical complexity of MIMVS.

Methods

One hundred and twenty-one patients underwent MIMVS in our institution between May 2014 and April 2020. These patients were categorized into two groups. The first group was the small physique group (n = 20) consisting of patients with a stature &lt;150 cm. The second group was the normal physique group (n = 101) consisting of patients with a stature &gt;150 cm. The primary endpoint was freedom from death and major adverse cardiovascular and cerebrovascular events (MACCE). The secondary endpoint was freedom from moderate or severe mitral regurgitation.

Results

Cardiopulmonary bypass time (130 ± 29 vs. 156 ± 55 min, p = 0.02) and aortic cross-clamp time (75 ± 27 vs. 95 ± 39 min, p = 0.03) were significantly shorter in the small physique group. Both in the early and midterm periods, there was no significant difference in the mortality (early, 5.0 vs. 1.0%, p = 0.30. midterm, 5.0 vs. 1.0%, p = 0.09), MACCE (early, 5.0 vs. 6.9%, p = 0.65. midterm, 5.0 vs. 5.9%, p = 0.93) and the residual MR (early, 0 vs. 1.0%, p = 0.66. midterm, 5.0 vs. 4.9%, p = 0.93) between the two groups.

Conclusions

Small physique is not a hurdle for MIMVS in terms of the safety of the operation.

Impact of Obesity on Atrial Fibrillation Recurrence Following Stand-Alone Cox Maze IV Procedure

OBJECTIVE

Obesity is a strong and independent factor for the development of atrial fibrillation (AF), and adversely impacts the success of catheter ablation procedures for AF. This study evaluated the impact of body mass index (BMI) on the outcomes following surgical ablation of AF.

METHODS

Between 2003 and 2019, 236 patients underwent a stand-alone biatrial Cox maze IV procedure (CMP-IV) for refractory AF. Obesity was defined as BMI ≥30 kg/m². Patients were divided into two groups: BMI <30 kg/m² (n = 100) and BMI ≥30 kg/m² (n = 136). Freedom from atrial tachyarrhythmia (ATA) was determined using electrocardiography, Holter, or pacemaker interrogation at 1 year and annually thereafter. Recurrence was defined as any documented ATA lasting ≥30 s. Predictors of recurrence were determined using multivariable logistic regression. Preoperative and procedural outcomes were compared between groups.

RESULTS

Obese patients had a higher rate of diabetes (16% vs 7%, P = 0.044) and larger left atrial diameter (4.9 ± 1.1 cm vs 4.6 ± 1.0 cm, P = 0.021) when compared to non-obese patients. There was no difference in major complication rate between the groups (4% vs 7%, P = 0.389). There was no operative mortality in either group. During 4.1 ± 2.4 years of follow-up, there was no significant difference in freedom from ATA with or without antiarrhythmic drugs in obese patients when compared to the non-obese group (P > 0.05). Absence of sinus rhythm at discharge predicted AF recurrence up to 7 years postoperatively.

CONCLUSIONS

As opposed to catheter ablation, obesity did not adversely impact the short and long-term outcomes of stand-alone surgical ablation with CMP-IV, and BMI was not a predictor of AF recurrence. Additionally, there was no significant increase in major complications in obese patients.

Sternal closure with single compared with double or figure of 8 wires in obese patients following cardiac surgery: A systematic review and meta-analysis

OBJECTIVES

Sternal instability and wound infections are major causes of morbidity following cardiac surgery, which is further amplified in high risk patients that include diabetics and patients with high body mass index (BMI). We compare the different outcomes of different sternal wire closure techniques following median sternotomy for cardiac surgery in obese patients.

METHODS

A comprehensive electronic literature search was undertaken according to PRISMA guidelines from inception to July 2020 to identify all published data comparing single wire sternal closure to either double wire or figure-of-8 techniques following median sternotomy for cardiac surgery in obese patients, defined as a BMI ≥ 30.

RESULTS

Eight studies met the final inclusion criteria; single wire versus double wire sternal closure (n = 2) and single wire versus figure-of-8 wire closure (n = 6). Higher rate of sternal instability was noted in single wire versus double wire closure (22/150 [14.7%] patients vs. 6/150 [4%] patients, p = 0.003, odd ratio [OR] 0.25 [95% confidence interval [CI] 0.10-0.63]). Similarly, sternal instability was higher in single wire vs figure-of-8 wire closure technique (33/2422 [1.3%] vs. 11/8035 [0.1%], p = 0.04 OR 0.30 [95% CI, 0.09-0.96]), respectively.

CONCLUSION

There is benefit in the use of either double or figure-of-8 sternal wire closure techniques over single wire closure in terms of sternal instability. However, as the studies were limited, larger scale comparative studies are required to provide a solid evidence base for choosing the optimal sternal closure technique in this high risk group of patients.

Adiposity in relation to readmission and all-cause mortality following coronary artery bypass grafting: A systematic review and meta-analysis

This study systemically reviewed evidence linking adiposity to readmission and all-cause mortality in post-coronary artery bypass grafting (CABG) patients. Keyword/reference search was performed in PubMed, Web of Science, CINAHL, and Cochrane Library for articles published before June, 2018. Eligibility criteria included study designs: experimental/observational studies; subjects: adult patients undergoing CABG; and outcomes: hospital/clinic readmissions, and short-term (≤30 days) and mid-to-long-term (>30 days) all-cause mortality. Seventy-two studies were identified. Meta-analysis showed that the odds of post-CABG readmission among patients with overweight was 30% lower than their normal-weight counterparts and the odds of mid-to-long-term post-CABG mortality among patients with overweight were 20% lower than their normal-weight counterparts. In contrast, no difference in post-CABG readmission rate was found between patients with obesity and their nonobese counterparts; no difference in short-term or in-hospital post-CABG mortality rate was found between patients with overweight or obesity and their normal-weight counterparts; and no difference in mid-to-long-term post-CABG mortality rate was found between patients with obesity and their normal-weight counterparts. In conclusion, patients with overweight but not obesity had a lower readmission and mid-to-long-term mortality rate following CABG relative to their normal-weight counterparts. Preoperative weight loss may not be advised to patients with overweight undergoing CABG.

Categorizing body mass index biases assessment of the association with post-coronary artery bypass graft mortality

OBJECTIVES

The high prevalence of obesity makes accurately estimating the impact of anthropometric measures on cardiac surgery outcomes critical. The Society of Thoracic Surgeons coronary artery bypass graft (CABG) surgery risk model includes body surface area (as a continuous variable, using spline functions), but most studies apply various categorizations of body mass index (BMI)-contributing to the contradictory published findings. We assessed the association between BMI (modelled as a continuous variable without assumptions of linearity) and CABG operative mortality and examined the impact of applying previous studies' BMI modelling strategies.

METHODS

We identified 25 studies investigating the BMI-operative mortality association: 22 categorized BMI, 2 as a linear continuous variable,1 used spline functions. Our cohort of 12 715 consecutive patients underwent isolated CABG at 32 cardiac surgery programmes in North Texas from 1 January 2008-31 December 2012. BMI was modelled using restricted cubic spline functions in a propensity-adjusted model (controlling for Society of Thoracic Surgeons risk factors) estimating operative mortality. The analysis was repeated using each categorization identified and modelling BMI as a linear continuous variable.

RESULTS

BMI (modelled with a restricted cubic spline) was significantly associated with operative mortality (P < 0.0001). Risk was lowest for BMI near 30 kg/m2 and highest below 20 kg/m2 and above 40 kg/m2. No categorization, nor the linear continuous model, fully captured this association.

CONCLUSIONS

BMI is strongly associated with CABG operative mortality. Categorizing BMI (or assuming a linear relationship) heavily biases estimates of its association with post-CABG mortality. In general, smoothing techniques should be used for all continuous risk factors to avoid bias.

Effect of Body Mass Index on Postoperative Complications in Beating Coronary Artery Surgery

BACKGROUND

Body Mass Index (BMI) is considered as an important risk factor in cardiovascular surgery. We designed a historical cohort study for the evaluation of perioperative complications related to BMI in patients who underwent off-pump coronary artery bypass grafting (OPCAB).

METHODS

We studied 1120 consecutive patients who underwent OPCAB between January 2008 and December 2011 in Imam Ali Hospital, Kermanshah, Iran. Patients were divided into four groups according to BMI: underweight/low BMI (< 18.5 kg/m²), healthy weight (between 18.5 kg/m² and 24.9 kg/m²), overweight/high BMI (between 25 kg/m² and 30 kg/m²), and obese/very high BMI (> 30 kg/m²).

RESULTS

In multivariable regression analysis, an important correlation between the underweight/low BMI group and mortality was observed (p=0.037). Postoperative stroke, postoperative atrial fibrillation (AF) and intra-aortic balloon pump (IABP) use were not associated with BMI. In linear regression analysis, significant correlations between low BMI, reintubation, ICU stay time and intubation time were found. Re-exploration for bleeding was significantly correlated with having a low or high BMI.

CONCLUSION

Having a low BMI (which is association with malnutrition and respiratory muscles weakness) was significantly associated with reintubation, prolonged intubation time and ICU stay time. The obese group was also associated with postoperative atelectasia and fever.

Aortic valve replacement in small patients

OBJECTIVES

Asians are smaller than Europeans and North Americans, but aortic valve replacement (AVR) in small patients has not been examined. We aimed to compare short- and mid-term outcomes of AVR between small and non-small patients.

METHODS

We retrospectively divided 173 patients who underwent AVR into small (S, n = 95) and non-small (NS, n = 78) groups according to body surface area (≤1.6 in men, ≤1.5 in women) and analyzed differences in baseline characteristics, procedural and post-procedural variables, and survival.

RESULTS

Mean age differed significantly between the S and NS groups (71.9 ± 11.2 vs. 66.2 ± 9.8 years), as did the proportion of women (60.0% vs. 24.4%). Implanted valves (19.6 ± 1.6 mm vs. 20.7 ± 1.7 mm) were significantly smaller and more bioprosthetic valves (57.9% vs. 41.0%) were used in the S group. Effective orifice area index and the rate of moderate and severe patient-prosthesis mismatch were not significantly different. No significant intergroup differences were found in hospitalization duration, 30-day mortality, survival rates, or valve related complications.

CONCLUSIONS

Small patients were older and the proportion of women was higher. The implanted aortic valves were smaller and more were biological prostheses. However, mortality rate did not differ and short- and mid-term outcomes were safe and favorable.

Factors influencing transfusion requirement in patients undergoing first-time, elective coronary artery bypass graft surgery

CONTEXT

Coronary artery bypass graft (CABG) operation is associated with high frequency of allogeneic blood transfusion due to the acquired hemostatic challenges in patients undergoing CABG. However, allogeneic blood transfusion carries risks of infection, adverse reaction, and mortality as well as prolonged hospital stay and increased hospital cost. It is important to identify patients who require blood transfusion to mitigate their risk factors and reduce the chance of exposure to allogeneic blood.

AIMS

This study was conducted to evaluate factors that influence the decision to transfuse red cell in first-time elective CABG patients.

SETTINGS AND DESIGN

This was a cross-sectional study based on a retrospective record review. The study was done in the National Heart Institute.

MATERIALS AND METHODS

All patients who underwent first-time elective CABG were included in this study. Variables analyzed include age, gender, body weight, preoperative hemoglobin (Hb) level, patients' comorbidities, and other clinical parameters.

STATISTICAL ANALYSIS USED

Data were analyzed using SPSS software version 20.

RESULTS

A total of 463 patients underwent first-time elective CABG during the period of the study. Three hundred and eighty-six (83.4%) patients received red cell transfusion. From multiple logistic regression analysis, only age (odds ratio [OR] = 1.040, 95% confidence interval [CI]: 1.003, 1.077, P = 0.032), body weight (OR = 0.951, 95% CI: 0.928, 0.974, P < 0.001), Hb level (OR = 0.500, 95% CI: 0.387, 0.644, P < 0.001), and cardiopulmonary bypass time (OR = 1.013, 95% CI: 1.004, 1.023, P < 0.001) were the significant independent predictors of red cell transfusion.

CONCLUSIONS

By stratifying patients according to their risk factor for red cell transfusion, the high-risk patients could be recognized and should be enrolled into effective patient blood management program to minimize their risk of exposure to allogeneic blood transfusion.

Economies of scale: body mass index and costs of cardiac surgery in Ontario, Canada

An obesity paradox has been described, whereby obese patients have better health outcomes than normal weight patients in certain clinical situations, including cardiac surgery. However, the relationship between body mass index (BMI) and resource utilization and costs in patients undergoing coronary artery bypass graft (CABG) surgery is largely unknown. We examined resource utilization and cost data for 53,224 patients undergoing CABG in Ontario, Canada over a 10-year period between 2002 and 2011. Data for costs during hospital admission and for a 1-year follow-up period were derived from the Institute for Clinical Evaluative Sciences, and analyzed according to pre-defined BMI categories using analysis of variance and multivariate models. BMI independently influenced healthcare costs. Underweight patients had the highest per patient costs ($50,124 ± $36,495), with the next highest costs incurred by morbidly obese ($43,770 ± $31,747) and normal weight patients ($42,564 ± $30,630). Obese and overweight patients had the lowest per patient costs ($40,760 ± $30,664 and $39,960 ± $25,422, respectively). Conversely, at the population level, overweight and obese patients were responsible for the highest total yearly population costs to the healthcare system ($92 million and $50 million, respectively, compared to $4.2 million for underweight patients). This is most likely due to the high proportion of CABG patients falling into the overweight and obese BMI groups. In the future, preoperative risk stratification and preparation based on BMI may assist in reducing surgical costs, and may inform health policy measures aimed at the management of weight extremes in the population.

Early and Mid-term Outcome of the St. Jude Medical Regent 19-mm Aortic Valve Mechanical Prosthesis. Functional and Haemodynamic Evaluation

BACKGROUND AND OBJECTIVES

The aim of the present study is to report the early and mid-term clinical and haemodynamic results of the St Jude Medical Regent 19-mm aortic mechanical prothesis (SJMR-19).

MATERIALS AND METHODS

Between January 2002 and January 2012, 265 patients with aortic valve disease underwent AVR (Aortic Valve Replacement) with a SJMR-19 (St Jude Medical Regent Nr.19). There were 51 males. Mean age was 67.5±12.72years and mean body surface area (BSA) was 1.67±0.14m2. Thirty-six patients required annulus enlargement. The mean follow-up was 34.5±18.8months (range 6-60 months). All patients underwent echocardiographic examination at discharge and within 1 year after surgery.

RESULTS

There were 14 (5.3%) hospital deaths. Six of the hospital deaths were identified in patients undergoing reoperation, significantly higher than patients undergoing first time operation (p=0.0001). Also the postoperative mortality was significantly higher in patients undergoing annulus enlargement versus patients not requiring annulus enlargement (p=0.02). The mean transprosthesis gradient at discharge was 19±9mmHg. At 6 months follow-up the mean NYHA FC class was 1.6±0.5 significantly lower than preoperatively 2.4±0.75 (p <0.0001). The M-TPG was 15.2±6.5mmHg within 1 year after surgery. Left ventricular mass (LVM) and indexed left ventricular mass (LVM_i) were significantly lower than preoperatively The actuarial survival and cumulative freedom from reoperation at 1, 2 and 3 years follow-up were 99.5%, 97.5%, 96.7% and 99.2%, 96.5%, 94.5% respectively. The cumulative actuarial free-events survival at 4 years was 92%. The Cox model identified age (p=0.015), LVEF≤35% (p=0.043), reoperation (p=0.031), combined surgery (p=0.00002), and annulus enlargement (p=0.015) as strong predictors for poor actuarial free-major events survival.

CONCLUSIONS

The SJMR-19 offers excellent postoperative clinical, haemodynamic outcome and LVM_i reduction in patients with small aortic annulus. These data demonstrate that the modern St Jude small mechanical protheses do not influence the intermediate free-reoperation survival.

Does Body Mass Index Affect Mortality in Coronary Surgery?

Introduction:

The Body Mass Index (BMI) quantifies nutritional status and classifies humans as underweight, of normal weight, overweight, mildly obese, moderately obese or morbidly obese. Obesity is the excessive accumulation of fat, defined as BMI higher than 30 kg/m². Obesity is widely accepted to complicate anaesthesia and surgery, being a risk factor for mediastinitis after coronary artery bypass grafting (CABG). We sought the evidence on operative mortality of CABG between standard BMI groups.

Materials and Methodology:

A simple literature review of papers presenting the mortality of CABG by BMI group: Underweight (BMI ≤ 18.49 kg/m²), normal weight (BMI 18.5–24.9 kg/m²), overweight (BMI 25.0–29.9 kg/m²), mild obesity (BMI 30.0–34.9 kg/m²), moderate obesity (BMI 35.0–39.9 kg/m²), or morbid obesity (BMI ≥ 40.0 kg/m²).

Results:

We identified 18 relevant studies with 1,027,711 patients in total. Their variability in size of samples and choice of BMI groups precluded us from attempting inferential statistics. The overall cumulative mortality was 2.7%. Underweight patients had by far the highest mortality (6.6%). Overweight patients had the lowest group mortality (2.1%). The group mortality for morbidly obese patients was 3.44%.

Discussion:

Patients with extreme BMI’s undergoing CABG (underweight ones more than morbidly obese) suffer increased crude mortality. This simple observation indicates that under nutrition and morbid obesity need be further explored as risk factors for coronary surgery.

The Effects of Different BMI on Blood Loss and Transfusions in Chinese Patients Undergoing Coronary Artery Bypass Grafting

OBJECTIVE

Blood loss is a predictor of outcomes after coronary artery bypass grafting (CABG). This study investigated the effects of body mass index (BMI) on blood loss, blood transfusion rate, and the variations in coagulation parameters of Chinese patients undergoing CABG.

METHODS

A total of 1007 Chinese patients who consecutively underwent isolated, primary CABG at Fuwai Hospital from January 1, 2013 to December 31, 2013 were included in this study. They were categorized by BMI into <24 kg/m² (low and normal weight group), 24≤ BMI <28 kg/m² (overweight group), and BMI ≥28 kg/m² (obese group). Following this BMI classification, the quantities of blood lost and recorded transfusions were analyzed.

RESULTS

Blood loss and transfusion rates were significantly higher in the low and normal weight group compared with the obese group (p <0.01). Chest tube drainage over 24 h, duration of intensive care unit (ICU) stay, and postoperative mechanical ventilation were higher as well (p <0.01). Atrial fibrillation was closely related to blood transfusion (p <0.001).

CONCLUSIONS

Obesity is a predictor for protection against blood loss and transfusion in Chinese people. Patients with low and normal BMI lost more blood per kg of their weight and had higher total transfused volume during isolated primary CABG. Atrial fibrillation was associated with high blood transfusion.

Does Gender Influence the Likelihood or Types of Complications Following Cardiac Surgery?

Over 410,000 cardiac surgeries are performed in American women each year. Women having coronary artery bypass graft (CABG) and valve surgery do so at an older age and with more cardiovascular risk factors than men. Women's smaller body size may also increase risk by increasing the technical difficulty of surgical procedures. Female CABG patients appear to have higher perioperative mortality and cardiac morbidity, although studies of neurologic outcomes in female CABG patients have produced equivocal findings. Women undergoing CABG tend to consume more hospital resources than men do in terms of blood transfusion, mechanical ventilation, and length of intensive care unit and overall hospital stay. With regard to valve surgery, women appear to have worse outcomes than men if the surgery is combined with a CABG operation. Women and men undergoing isolated aortic valve surgery have similar mortality, but little is known about gender differences in mitral and tricuspid valve surgery outcomes. Women who require heart transplantation tend to have idiopathic cardiomyopathy rather than the ischemic cardiomyopathy that is more common in male heart transplant candidates. Although female heart transplant recipients seem to have a stronger immunologic response after transplantation, which manifests in more frequent acute rejection episodes, it is not clear whether this increases women's mortality risk. Men appear to have a greater incidence of posttransplant vasculopathy than women. Further research is needed to identify risk factors for perioperative morbidity and mortality in women undergoing cardiac surgery and to develop medical interventions to mitigate these risks.

Obese ICU Patients

This project described prospectively obese, critically ill patients and the resources critical care nurses used to care for these challenging patients. It also examined the relationship between resources used by nurses and patient outcomes, including complications and length of stay. Forty-three participants were enrolled. Patients with a body mass index (BMI) 40 kg/m2 used the majority of equipment and personnel resources and experienced a prolonged length of stay. The most common equipment used was a specialty bed or mattress; the most common complications were related to the pulmonary system. Initial use of multiple resources may indicate a patient at risk for adverse outcomes. Nurses can use findings to anticipate care needs and develop interventions, such as optimal positioning, to avoid adverse outcomes.

Severe Obesity Is Associated With Increased Risk of Early Complications and Extended Length of Stay Following Coronary Artery Bypass Grafting Surgery

Background

Better understanding of the relationship between obesity and postsurgical adverse outcomes is needed to provide quality and efficient care. We examined the relationship of obesity with the incidence of early adverse outcomes and in‐hospital length of stay following coronary artery bypass grafting surgery.

Methods and Results

We analyzed data from 7560 patients who underwent coronary artery bypass grafting. Using body mass index (BMI; in kg/m²) of 18.5 to 24.9 as a reference, the associations of 4 BMI categories (25.0–29.9, 30.0–34.9, 35.0–39.9, and ≥40.0) with rates of operative mortality, overall early complications, subgroups of early complications (ie, infection, renal and pulmonary complications), and length of stay were assessed while adjusting for clinical covariates. There was no difference in operative mortality; however, higher risks of overall complications were observed for patients with BMI 35.0 to 39.9 (adjusted odds ratio 1.35, 95% CI 1.11–1.63) and ≥40.0 (adjusted odds ratio 1.56, 95% CI 1.21–2.01). Subgroup analyses identified obesity as an independent risk factor for infection (BMI 30.0–34.9: adjusted odds ratio 1.60, 95% CI 1.24–2.05; BMI 35.0–39.9: adjusted odds ratio 2.34, 95% CI 1.73–3.17; BMI ≥40.0: adjusted odds ratio 3.29, 95% CI 2.30–4.71). Median length of stay was longer with BMI ≥40.0 than with BMI 18.5 to 24.9 (median 7.0 days [interquartile range 5 to 10] versus 6.0 days [interquartile range 5 to 9], P=0.026).

Conclusions

BMI ≥40.0 was an independent risk factor for longer length of stay, and infection was a potentially modifiable risk factor. Greater perioperative attention and intervention to control the risks associated with infection and length of stay in patients with BMI ≥40.0 may improve patient care quality and efficiency.

Effect of body mass index in acute respiratory distress syndrome

BACKGROUND

Obesity is associated in healthy subjects with a great reduction in functional residual capacity and with a stiffening of lung and chest wall elastance, which promote alveolar collapse and hypoxaemia. Likewise, obese patients with acute respiratory distress syndrome (ARDS) could present greater derangements of respiratory mechanics than patients of normal weight.

METHODS

One hundred and one ARDS patients were enrolled. Partitioned respiratory mechanics and gas exchange were measured at 5 and 15 cm H2O of PEEP with a tidal volume of 6-8 ml kg(-1) of predicted body weight. At 5 and 45 cm H2O of PEEP, two lung computed tomography scans were performed.

RESULTS

Patients were divided as follows according to BMI: normal weight (BMI≤25 kg m(-2)), overweight (BMI between 25 and 30 kg m(-2)), and obese (BMI>30 kg m(-2)). Obese, overweight, and normal-weight groups presented a similar lung elastance (median [interquartile range], respectively: 17.7 [14.2-24.8], 20.9 [16.1-30.2], and 20.5 [15.2-23.6] cm H2O litre(-1) at 5 cm H2O of PEEP and 19.3 [15.5-26.3], 21.1 [17.4-29.2], and 17.1 [13.4-20.4] cm H2O litre(-1) at 15 cm H2O of PEEP) and chest elastance (respectively: 4.9 [3.1-8.8], 5.9 [3.8-8.7], and 7.8 [3.9-9.8] cm H2O litre(-1) at 5 cm H2O of PEEP and 6.5 [4.5-9.6], 6.6 [4.2-9.2], and 4.9 [2.4-7.6] cm H2O litre(-1) at 15 cm H2O of PEEP). Lung recruitability was not affected by the body weight (15.6 [6.3-23.4], 15.7 [9.8-22.2], and 11.3 [6.2-15.6]% for normal-weight, overweight, and obese groups, respectively). Lung gas volume was significantly lower whereas total superimposed pressure was significantly higher in the obese compared with the normal-weight group (1148 [680-1815] vs 827 [686-1213] ml and 17.4 [15.8-19.3] vs 19.3 [18.6-21.7] cm H2O, respectively).

CONCLUSIONS

Obese ARDS patients do not present higher chest wall elastance and lung recruitability.

The impact of hyperglycemia and obesity on hospitalization costs and clinical outcome in general surgery patients

BACKGROUND

The impact of obesity on clinical outcomes and hospitalization costs in general surgery patients with and without diabetes (DM) is unknown.

MATERIALS AND METHODS

We reviewed medical records of 2451 patients who underwent gastrointestinal surgery at two university hospitals. Hyperglycemia was defined as BG ≥140 mg/dl. Overweight was defined by body mass index (BMI) between 25-29.9 kg/m(2) and obesity as a BMI ≥30 kg/m(2). Hospital cost was calculated using cost-charge ratios from Centers for Medicare and Medicaid Services. Hospital complications included a composite of major cardiovascular events, pneumonia, bacteremia, acute kidney injury (AKI), respiratory failure, and death.

RESULTS

Hyperglycemia was present in 1575 patients (74.8%). Compared to patients with normoglycemia, those with DM and non-DM with hyperglycemia had higher number of complications (8.9% vs. 35.8% vs. 30.0%, p<0.0001), longer hospital stay (5 days vs. 9 days vs. 9 days, p<0.0001), more readmissions within 30 days (9.3% vs. 18.8% vs. 17.2%, p<0.0001), and higher hospitalization costs ($20,273 vs. $79,545 vs. $72,675, p<0.0001). In contrast, compared to normal-weight subjects, overweight and obesity were not associated with increased hospitalization costs ($58,313 vs. $58,173 vs. $66,633, p=0.74) or risk of complications, except for AKI (11.9% vs. 14.8% vs. 20.5%, p<0.0001). Multivariate analysis revealed that DM (OR=4.4, 95% CI=2.8,7.0) or perioperative hyperglycemia (OR=4.1, 95% CI=2.7-6.2) were independently associated with increased risk of complications.

CONCLUSION

Hyperglycemia but not increasing BMI, in patients with and without diabetes undergoing gastrointestinal surgery was associated with a higher number of complications and hospitalization costs.

Hemodynamics of 17-mm vs. 19-mm St. Jude Medical Regent and annulus enlargement

OBJECTIVE

We aimed to compare early and midterm clinical and hemodynamic outcomes of 17-mm vs. 19-mm St. Jude Medical Regent valves with concomitant aortic annulus enlargement.

METHODS

Between 1999 and 2012, 20 patients (group 1) underwent first-time aortic valve replacement with a 17-mm St. Jude Medical Regent valve, and 35 patients (group 2) had a 19-mm valve and concomitant aortic annulus enlargement. The mean follow-up was 81 ± 37 months (range 20-110 months).

RESULTS

There was one death in group 1 vs. 4 in group 2 (p > 0.05). The mean postoperative transprosthetic gradient was 17.5 ± 4.5 in group 1 and 17 ± 6.4 mm Hg in group 2 (p = 0.83), and 37 ± 10.7 and 32 ± 13 mm Hg, respectively, under stress (p = 0.17). Left ventricular mass and left ventricular mass index were reduced and similar in both groups. Postoperative effective orifice area index was higher in group 2 (0.85 ± 0.17 cm(2 )m(-2)) than group 1 (0.76 ± 0.2 cm(2 )m(-2); p > 0.05). A multivariate Cox model identified a 19-mm valve with aortic annulus enlargement (p = 0.032), functional class (p = 0.025), reoperation (p = 0.04), ejection fraction < 35% (p = 0.042), and combined surgery (p = 0.04) as strong predictors of poorer overall event-free survival.

CONCLUSIONS

The 17-mm St. Jude Medical Regent valve may be employed with satisfactory postoperative clinical and hemodynamic outcomes in patients with a small aortic annulus, as an alternative to a larger prothesis with aortic annulus enlargement.

The obesity paradox in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Obesity is a major risk factor for cardiovascular morbidity and mortality. A considerable number of studies, however, showed better outcomes for overweight patients undergoing cardiovascular interventions-the so called obesity paradox.

HYPOTHESIS

Increased body mass index (BMI) is independently associated with improved survival following transcatheter aortic valve implantation (TAVI).

METHODS

We analyzed the data of 409 consecutive patients undergoing TAVI in our medical center. Patients were categorized into 4 groups according to BMI: underweight (≤18.4 kg/m(2) ), normal weight (18.5-24.9 kg/m(2) ), overweight (25-29.9 kg/m(2) ), and obese (≥30 kg/m(2) ). Procedure-related complications were recorded, as well as 30-day and 1-year all-cause mortality rates.

RESULTS

Obese patients had a higher prevalence of comorbidities and higher incidence of vascular complications compared with the normal-weight patients (16% vs 7%, P = 0.013). Nevertheless, 30-day mortality was similar among the groups, whereas 1-year mortality was lower among the overweight and obese patients (BMI >25) (P = 0.038). After adjusting for differences in baseline characteristics, increase in BMI was found to be independently associated with improved survival following TAVI (hazard ratio: 0.94, confidence interval: 0.89-0.99, P = 0.043).

CONCLUSIONS

In our single-center study, obesity and overweight were independently associated with better outcome, supporting the obesity paradox in the TAVI population.

Hypovitaminosis D in a sunny country: time trends, predictors, and implications for practice guidelines

The aim of the current study is to investigate the prevalence of hypovitaminosis D in Lebanese subjects, its robust predictors, evaluate the relationship between 25 hydroxy vitamin D [25(OH)D] and parathyroid hormone levels, and derive desirable vitamin D levels, based on a large hospital laboratory database spanning all age groups. Data from a large representative digitized database of 9147 subjects, mostly outpatients, evaluated between 2000-2004 and 2007-2008, in whom information on age, gender, service, and time of the year, was analyzed. The PTH-25(OH)D relationship was studied in a subset of 657 adult subjects, in whom such data were available. At a 25(OH)D cut-off of<20 ng/ml, the prevalence of hypovitaminosis D ranged between 58% and 62% in pediatric subjects, 44% and 60% in adults, and 41% and 62% in elderly, in the 2 study periods. At a cut-off <30 ng/ml, the prevalence was above 78%, in most sub-groups. Regardless of cut-off used, the only significant predictors of high mean 25(OH)D levels were the male gender in the pediatric group, and female gender in adults and elderly, summer/fall seasons, out-patient status, as well as study period. Curve fitting of the PTH-25(OH)D relationship, in adults and elderly, revealed a plateau at 25(OH)D levels of 17-21 ng/ml, depending on sub-study group. Hypovitaminosis D is prevalent in our sunny country, even using a conservative population-derived cut-off of 20 ng/ml, and thus the need for a public health strategy for supplementation.

Is crystalloid cardioplegia a strong predictor of intra-operative hemodilution?

INTRODUCTION

Complications due to hemodilution (hematocrit value less than 22%) after cardiopulmonary bypass inevitably resulted with significantly greater intensive care requirements, long hospital stays, more operative costs, and increased mortality rates. We tried to identify whether crystalloid cardioplegia is the strongest predictor of intraoperative hemodilution or not.

MATERIALS AND METHODS

One hundred patients were included into this randomized prospective study. Patients were divided into the two groups. Crystalloid cardioplegia were given to the odd-numbered patients (Group 1, n=50 patients) and blood cardioplegia were given to the even-numbered patients (Group 2, n=50 patients). St. Thomas-II solution was used in Group-1 and Calafiore cold blood cardioplegia was in Group-2.

RESULTS

Average intraoperative hematocrit value was 18.4% ± 2.3 in crystalloid group 24.2% ± 3.4 in blood cardioplegia group (p<0.001). The lowest hematocrit value was 15% and 20% in two groups respectively (p<0.001). In crystalloid group average intraoperative packed red blood cell (RBC) transfusion was 2.3 ± 0.41 units, 0.7 ± 0.6 units blood cardioplegia group (p=0.001). Average transfused RBC was 2.7 ± 0.8 units in crystalloid group, 0.9 ± 0.4 units blood cardioplegia group (p<0.001). Multivariate analyses confirmed age (p = 0.005, OR = 3.78), female gender (p = 0.003, OR = 2.91), longer cross-clamp time (>60 minutes) (p = 0.001, OD = 0.97), body surface area <1.6 m2 (p = 0.001, OR = 6.01) and crystalloid cardioplegia (p < 0.001, OR = 0.19) as predictor of intraoperative hemodilution.

CONCLUSION

Crystalloid cardioplegia, compared to blood cardioplegia not only causes much more intra-operative hemodilution but also increases the blood transfusion requirement. Hemodilution and increased transfusion increases the intensive care unit and hospital stay, in the early postoperative period.

BMI Is an Independent Preoperative Predictor of Intraoperative Transfusion and Postoperative Chest-Tube Output

Background An increasing obese population in the United States focuses attention on perioperative management of obese and overweight patients. Objective We sought to determine if obesity, determined by body mass index (BMI), was a preoperative indicator of bleeding in coronary artery bypass graft (CABG) surgery as measured by intraoperative packed red blood cell transfusion frequency and 24-hour chest-tube output amount. Methods A retrospective chart review examined 290 consecutive patients undergoing single-surgeon off-pump or on-pump CABG surgery between November 2003 and April 2009. Preoperative variables of age, gender, hematocrit, platelet count, and BMI, chest tube output during the immediate 24-hour postoperative period, and the type of procedure (on-pump vs. off-pump) were analyzed. Logistic regression analysis was used to evaluate the likelihood of intraoperative transfusion. Linear regression analysis was used to evaluate 24-hour chest-tube output. Results Preoperative variables that significantly increased the likelihood of intraoperative transfusions were older age and low hematocrit; a significant decrease in likelihood was found with male gender, overweight BMI, and off-pump procedures. Preoperative variables that significantly increased 24-hour chest-tube output were low hematocrit, high hematocrit, and low platelets while a significant decrease in output was seen with overweight BMI and obese BMI. Conclusion Overweight and obese BMI are significant independent predictors of decreased intraoperative transfusion and decreased postoperative blood loss.

An obesity paradox of Asian body mass index after cardiac surgery: arterial oxygenations in duration of mechanic ventilation

BACKGROUND

Numerous studies have documented an obesity paradox that overweight of Caucasian patients has better prognosis after cardiac surgery. This study is to examine Asian patients' BMI to see whether an obesity paradox exists in DMV after cardiac surgery.

METHODS

A retrospective study consisted of 428 patients after cardiac surgery from January 2006 to December 2010 in the medical center of Taiwan. The Asian BMI was divided into 3 groups: under-normal weight patients (BMI < 24; n = 165), overweight patients (BMI 24 to <27; n = 130), and obese patients (BMI ≥ 27; n = 133). Multivariable analysis and paired t were used to compare all variables.

RESULTS

Overweight patients were significantly associated with the shortest DMV. Under-normal weight patients had significantly better oxygenations of AaDO₂ and P/F ratio in the DMV; however, they correlated with the longest DMV, older age, more female, lower LVSV, higher BUN, more dialysis-dependent, and poorer outcomes, namely, 1-year mortality, HAP, reintubation, tracheotomy, and LOS.

CONCLUSIONS

Asian overweight patients after cardiac surgery have better prognosis. Under-normal weight patients have higher risk factors, longer DMV, and poorer outcomes; even though they have better arterial oxygenations, they seem to need better arterial oxygenations for successful weaning ventilator.

New insights into the true nature of the obesity paradox and the lower cardiovascular risk

Obesity is considered a major risk factor for cardiovascular disease, hypertension, and diabetes by National and International Committees. For this reason, they advocate weight loss and prevention of obesity. However, several studies in patients with established coronary artery disease (CAD), congestive heart failure, and hypertension have shown an inverse relationship between obesity and mortality, the so called "obesity paradox," whereas other studies have not shown such a relationship. In studies showing the obesity paradox (OP), body mass index (BMI) was used, almost exclusively as an index of obesity, although is a poor discriminator of total body fatness. Recent studies using better indices of obesity such as waist circumference (WC) and waist to hip ratio (WHR) have shown that high WC and WHR were directly and positively associated with higher event rate and total mortality in these patients. Because the OP could convey the wrong message in obese patients, the validity and true nature of the OP will be examined in this concise review. A Medline search of the English literature was performed between 2000 and September 2012, and 46 pertinent articles were selected for this review. The majority of these studies do not support an OP and those that do have used almost exclusively BMI as an index of obesity. Therefore, based on recent studies using other indices of body fat distribution, such as WC and WHR, besides BMI, the true existence of OP has been questioned and needs to be confirmed by future studies.

The corpulent phenotype-how the brain maximizes survival in stressful environments

The reactivity of the stress system may change during the life course. In many—but not all—humans the stress reactivity decreases, once the individual is chronically exposed to a stressful and unsafe environment (e.g., poverty, work with high demands, unhappy martial relationship). Such an adaptation is referred to as habituation. Stress habituation allows alleviating the burden of chronic stress, particularly cardiovascular morbidity and mortality. Interestingly, two recent experiments demonstrated low stress reactivity during a mental or psychosocial challenge in subjects with a high body mass. In this focused review we attempt to integrate these experimental findings in a larger context. Are these data compatible with data sets showing a prolonged life expectancy in corpulent people? From the perspective of neuroenergetics, we here raise the question whether “obesity” is unhealthy at all. Is the corpulent phenotype possibly the result of “adaptive phenotypic plasticity” allowing optimized survival in stressful environments?

Body mass index—predictor of outcome after coronary artery bypass grafting

Objective: Increased body mass index has been associated with increased postoperative morbidity. We studied the effect of body mass index in our population, using a modified scale suggested by the World Health Organization.

Methods: From January 2006 to December 2008, 1019 patients undergoing first-time isolated elective coronary artery bypass grafting were selected from our cardiac surgery database. Data were analyzed by univariate and multivariate analyses.

Results: Of the 1019 elective coronary artery bypass patients, 168 (15.8%) had a normal body mass index (18.5–22.9 kg·m−2) and 894 (84.2%) had a high body mass index (≥23.0 kg·m−2). There were 921 (86.7%) patients with 3-vessel disease, and 1012 (95.3%) had internal mammary artery grafts. The 30-day mortality was 0.8%. Multivariate analysis revealed age, hospital stay, perfusion time, and renal failure were significantly associated with hospital complications. High body mass index was not significantly associated with morbidity or mortality. The model had an adequate fit at p = 0.708 by the Hosmer and Lemeshow test.

Conclusion: Increased body mass index alone is not a predictor of increased mortality and morbidity. In fact, these outcomes were associated with advanced age, hospital stay, perfusion time, and renal failure.

Risk Factors of Red Blood Cell Transfusion in Isolate off Pump Coronary Artery Bypass Surgery

BACKGROUND

Perioperative transfusion of red blood cell (RBC) may cause adverse effects. Bloodless-cardiac surgery has been spotlighted to avoid those problems. Off pump coronary artery bypass (OPCAB) surgery can decrease the transfusion. However, the risk factors of transfusions in OPCAB have not been investigated properly.

MATERIALS AND METHODS

One hundred and thirteen patients (male:female=35:78, mean age=66.7±9.9 years) who received isolated OPCAB were retrospectively analyzed from March 2006 to September 2007. The threshold of RBC transfusion was 28.0% of hematocrit. Bilateral internal thoracic arteries graft were used for 99 patients (87.6%). One hundred and three (91.1%) and 35 patients (31.5%) took aspirin and clopidogrel just before surgery.

RESULTS

Sixty-five patients (47.5%) received the RBC transfusion (mean 2.2±3.2 units). Mortality and major complications were not different between transfusion and no-transfusion group. But, ventilator support time, intensive care unit stay and hospitalization period had been reduced in no-transfusion group (p<0.05). In multivariate analysis, patients risk factors for RBC transfusion were preoperative low hematocrit (<37.5%) and clopidogrel medication. Surgical risk factors were longer graft harvesting time (>75 minutes) and total operation time (>5.5 hours, p<0.05).

CONCLUSION

We performed the transfusion according to transfusion guideline; over 40% cases could conduct the OPCAB without transfusion. There were no differences in major clinical results between transfusion and non-transfusion group. In addition, when used together with accurate understanding of transfusion risk factors, it is expected to increase the proportion of patients that do not undergo transfusions.

Prevention of sternal dehiscence with the sternum external fixation (Stern-E-Fix) corset--randomized trial in 750 patients

Background

The main objective of this study will be to determine the effects of a new advanced sternum external fixation (Stern-E-Fix) corset on prevention of sternal instability and mediastinitis in high-risk patients.

Methods

This prospective, randomized study (January 2009 – June 2011) comprised 750 male patients undergoing standard median sternotomy for cardiac procedures (78% CABG). Patients were divided in two randomized groups (A, n = 380: received a Stern-E-Fix corset postoperatively for 6 weeks and B, n = 370: control group received a standard elastic thorax bandage). In both groups, risk factors for sternal dehiscence and preoperative preparations were similar.

Results

Wound infections occurred in n = 13 (3.42%) pts. in group A vs. n = 35 (9.46%) in group B. In group A, only 1 patient presented with sternal dehiscence vs. 22 pts. in group B. In all 22 patients, sternal rewiring followed by antibiotic therapy was needed. Mediastinitis related mortality was none in A versus two in B. Treatment failure in group B was more than five times higher than in A (p = 0.01); the mean length of stay in hospital was 12.5 ± 7.4 days (A) versus 18 ± 15.1 days (B) (p=0.002). Re-operation for sternal infection was 4 times higher in group B. Mean ventilation time was relatively longer in B (2.5 vs. 1.28 days) (p = 0.01). The mean follow-up period was 8 weeks (range 6 – 12 weeks).

Conclusions

We demonstrated that using an external supportive sternal corset (Stern-E-Fix) yields a significantly better and effective prevention against development of sternal dehiscence and secondary sternal infection in high-risk poststernotomy patients.

Figure-of-eight versus prophylactic sternal weave closure of median sternotomy in diabetic obese patients undergoing coronary artery bypass grafting

BACKGROUND

Sternal dehiscence is a serious and potentially devastating complication after median sternotomy, especially in diabetic obese patients. The optimal technique for sternal closure is unclear in these patients.

METHODS

The purpose of this prospective randomized study was to compare the incidence of sternal dehiscence after prophylactic sternal weave and figure-of-eight suturing in diabetic obese patients undergoing coronary artery bypass grafting (CABG). The patients were randomly assigned to group A (figure-of-eight closure; n=75) or group B (sternal weave closure; n=75).

RESULTS

There were 8 cases of sternal dehiscence documented: 7 in group A and 1 in group B. In group A, 5 patients had noninfectious sternal dehiscence and 2 patients underwent reoperation because of sternal dehiscence with mediastinitis. Also, 1 of the noninfected patients had deep-seated pain with a feeling of bony crepitus and needed reoperation. The other 4 patients in group A and 1 patient with noninfectious sternal dehiscence in group B were given chest binder support. Pain and bony crepitus decreased in the follow-up period of 1 year. Sternal dehiscence rates were 9.3% in group A and 1.3% in group B. Sternal dehiscence was significantly lower in group B (p<0.05).

CONCLUSIONS

Prophylactic sternal weave closure of median sternotomy reduces morbidity from sternal dehiscence in diabetic obese patients undergoing CABG.

The impact of obesity on critical care resource use and outcomes

Obese patients in the ICU present unique challenges to the health care team and specific challenges to nurses. This article reviews the science and art of resource use for obese patients in the ICU. Staff nurses and advanced practice nurses can make important contributions in evaluating optimal resource use and improving outcomes in this population of vulnerable patients.

Effects of sex, body mass index, and body size on the outcome of coronary artery bypass surgery: Iranian experience

OBJECTIVE

Sex, body mass index, and body surface area have been proposed as important determinants of outcome after coronary artery bypass graft surgery.

METHODS

In a retrospective study, the archived files of the patients who had undergone isolated coronary artery bypass graft (CABG) in our center from January 2005 to September 2008 were evaluated. The data regarding the patients' body surface area (BSA), body mass index (BMI), and laboratory tests as well as their demographic data and the number of deaths, duration of intensive care unit (ICU) stay, and duration of hospital admissions were collected. Duration of ICU stay >4 days and death were considered for the final outcomes to present the morbidity and mortality, respectively.

RESULTS

In total, the files of 1223 patients were reviewed. BSA was different between men and women, but the differences in mortality and morbidity were not statistically significant. The difference between the mean BMI in men and women was not significant (P = 0.72). In all, 11 patients (9 men, 2 women) died during the hospital stay, but no significant difference was observed between the men and the women (P = 0.59). Among the patients, 6.5% stayed >4 days in the ICU (50 men, 20 women) with no significant difference between the two (P = 0.482). No significant differences were found between the BSA and BMI of the patients who died and those who were discharged from the hospital (P = 0.088 and P = 0.321, respectively). There were no significant correlations between the duration of hospital stay and the BSA or BMI (P = 0.44 and P = 0.26, respectively).

CONCLUSION

Sex, BMI, and BSA do not affect the outcome after CABG.

Preoperative creatinine clearance as a predictor of short-term outcomes after cardiac surgery: a cohort study for the comparison between the Cockroft-Gault and modification of diet in renal disease formulae

BACKGROUND

Preoperative renal function is an important risk factor in cardiac surgery for long-term and short-term outcomes. Renal function is best assessed by measuring or calculating the glomerular filtration rate (GFR). Several algorithms using the endogenous marker serum creatinine have been developed to estimate renal function. These include the Cockcroft and Gault and the modification of diet in renal disease (MDRD) formulae. The aim of this study was to compare the predictive power of the two formulae towards short-term outcomes after cardiac surgery, such as the length of intensive care unit (ICU) stay, the length of mechanical ventilation time, and the length of in-hospital stay.

METHODS

One hundred and fifty patients undergoing cardiac surgery and not affected by renal failure were followed up until hospital discharge. We collected data before, during and after surgery. Before surgery data consisted of date of birth, sex, height, weight, plasma creatinine level; during surgery data consisted of type of intervention (including number of bypasses, if any), cardiopulmonary bypass time and aortic cross-clamp time; after surgery data consisted of length of ICU stay, mechanical ventilation time, length of in-hospital stay after intensive-care discharge (ward stay), incidence of acute renal failure (expressed as the need for dialysis) and mortality. The dataset was analyzed using Cox regression.

RESULTS

The average mechanical ventilation time, ICU stay and ward stay were 11 h, 49 h and 10 days, respectively. After having adjusted for chronic obstructive pulmonary disease, diabetes and postsurgical dialysis, the GFR calculated with the Cockcroft and Gault formula appeared to be a predictor of ICU stay and mechanical ventilation time with very strong evidence (P = 0.002 and <0.001, respectively) and a predictor of ward stay with some evidence (P = 0.062). After an identical case-mix adjustment, the GFR calculated with the MDRD formula appeared to be a predictor of ICU stay with strong evidence (P = 0.007), a predictor of mechanical ventilation time with some evidence (P = 0.075) and it has shown no evidence of predicting ward stay (P = 0.197).

CONCLUSION

There is an indication that the Cockcroft and Gault formula could be more powerful than the MDRD formula for the preoperative prediction of early postoperative clinical outcomes in cardiac surgery, in patients not affected by renal failure. Further research is needed to confirm this result.

The impact of obesity on long-term survival after coronary artery bypass grafting

BACKGROUND

Obesity is a well-known risk factor for coronary artery disease. The objective of our study was to examine the impact of obesity on long-term survival after coronary artery bypass grafting (CABG).

MATERIALS AND METHODS

Using prospectively gathered data, we reviewed records of 1163 consecutive patients who underwent isolated primary CABG between 1997 and 2007. We compared outcomes of obese patients (body mass index [BMI] > or = 30 kg/m(2); n = 472) and non-obese patients (BMI < 30 kg/m(2); n = 691). Long-term survival was assessed by using Kaplan-Meier curves generated by log-rank tests and adjusted for confounding factors with Cox logistic regression analysis.

RESULTS

Obese patients were slightly younger (60 +/- 8 versus 63 +/- 9y; P < 0.0001), were less likely to be current tobacco smokers (30% versus 41%; P < 0.0001), had a higher incidence of diabetes (51% versus 33%; P < 0.0001), and had a lower incidence of cerebral vascular disease (18% versus 24%; P = 0.009) than non-obese patients. The two groups of patients had similar 30-d rates of mortality (1.3% versus 1.5%; P = 0.8) and major adverse cardiac events (2.3% versus 2.5%; P = 0.9). Adjusted Cox regression survival curves were also similar between the two groups of patients (adjusted hazard ratio, 1.2; 95% confidence interval, 0.8-1.8; P = 0.28).

CONCLUSIONS

Obese patients who underwent CABG had 30-d mortality rates and early outcomes similar to those of non-obese patients. Long-term survival was also similar between these two groups of patients after adjustment for confounding variables.

Body mass index (BMI) and risk of noncardiac postoperative medical complications in elderly hip fracture patients: a population-based study

BACKGROUND

Obese patients are thought to be at higher risk of postoperative medical complications. We determined whether body mass index (BMI) is associated with postoperative in-hospital noncardiac complications following urgent hip fracture repair.

METHODS

We conducted a population-based study of Olmsted County, Minnesota, residents operated on for hip fracture in 1988 to 2002. BMI was categorized as underweight (<18.5 kg/m2), normal (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (> or = 30 kg/m2). Postoperative inpatient noncardiac medical complications were assessed. Complication rates were estimated for each BMI category and overall rates were assessed using logistic regression modeling.

RESULTS

There were 184 (15.6%) underweight, 640 (54.2%) normal, 251 (21.3%) overweight, and 105 (8.9%) obese hip fracture repairs (mean age, 84.2 +/- 7.5 years; 80% female). After adjustment, the risk of developing an inpatient noncardiac complication for each BMI category, compared to normal BMI, was: underweight (odds ratio [OR], 1.33; 95% confidence interval [CI], 0.95-1.88; P = 0.10), overweight (OR, 1.01; 95% CI, 0.74-1.38; P = 0.95), and obese (OR, 1.28; 95% CI, 0.82-1.98; P = 0.27). Multivariate analysis demonstrated that an ASA status of III-V vs. I-II (OR, 1.84; 95% CI, 1.25-2.71; P = 0.002), a history of chronic obstructive pulmonary disease (COPD) or asthma (OR, 1.58; 95% CI, 1.18-2.12; P = 0.002), male sex (OR, 1.49; 95% CI, 1.10-2.02; P = 0.01), and older age (OR, 1.05; 95% CI, 1.03-1.06; P < 0.001) contributed to an increased risk of developing a postoperative noncardiac inpatient complication. Underweight patients had higher in-hospital mortality rates than normal BMI patients (9.3 vs. 4.4%; P = 0.01).

CONCLUSIONS

BMI has no significant influence on postoperative noncardiac medical complications in hip-fracture patients. These results attenuate concerns that obese or frail, underweight hip-fracture patients may be at higher risk postoperatively for inpatient complications.