Effect of cardiac surgery patient characteristics on patient outcomes from 1981 through 1995

Effect of Goal-directed Hemodynamic Therapy in Postcardiac Surgery Patients

Background and aims

Early goal-directed therapy (EGDT) provides preset goals to be achieved by intravenous fluid therapy and inotropic therapy with earliest detection of change in the hemodynamic profile. Improved outcome in cardiac surgery patients has been shown by perioperative volume optimization, while postoperative intensive care unit (ICU) stay can be decreased by improving oxygen delivery. Our aim of this study was to study the outcome of EGDT in patients undergoing elective cardiac surgery.

Materials and methods

This is a prospective single institute study involving a total of 478 patients. Patients were divided into group I, who received standard hospital care, and group II, who received EGDT. Postoperatively, patients were observed in ICU for 72 hours. Hemodynamics, laboratory data, fluid bolus, inotrope score, complication, ventilatory time, and mortality data were collected.

Results

Postoperative ventilatory period (11.12 ± 10.11 vs 9.45 ± 8.87, p = 0.0719) and frequency of change in inotropes (1.900 ± 0.9 vs 1.19 ± 0.61, p = 0.0717) were lower in group II. Frequency of crystalloid boluses (1.33 ± 0.65 vs 1.75 ± 1.09, p = 0.0126), and quantity of packed cell volume (PCV) used (1.63 ± 1.03 vs 2.04 ± 1.42, p = 0.0364) were highly significant in group II. Use of colloids was higher in group II and was statistically significant (1.98 ± 1.99 vs 3.05 ± 2.17, p = 0.0012). The acute kidney injury (AKI) rate was (58 (23.10%) vs 30 (13.21%), p = 0.007) lower and statistically significant (p = 0.007) in group II.

Conclusion

Early goal-directed therapy reduces the postoperative ventilatory period, frequency of changes in inotropes, and incidence of AKI, and decreases ventilation hours, number of times inotropes changed, and AKI.

How to cite this article

Patel H, Parikh N, Shah R, Patel R, Thosani R, Shah P, et al. Effect of Goal-directed Hemodynamic Therapy in Postcardiac Surgery Patients. Indian J Crit Care Med 2020;24(5):321-326.

Fragmented QRS complexes are associated with postoperative atrial fibrillation development after coronary artery bypass grafting surgery

OBJECTIVE

Postoperative atrial fibrillation (PoAF) is one of the most frequent complications and a major risk factor of morbidity and mortality after coronary artery bypass grafting (CABG). Fragmented QRS complex (fQRS) on a 12-lead surface ECG is recently gained increasing attention as a simplified noninvasive ECG marker with diagnostic and prognostic value in various cardiac conditions. The aim of the present study was to evaluate the association between development of PoAF and presence of fQRS on admission ECG in patients undergoing CABG surgery.

METHODS

A total of 242 patients who underwent CABG between February 2016 and June 2018 were included in this study. The patients were divided into two groups as developing and nondeveloping PoAF groups in the postoperative period. fQRS was defined as the presence of various RSR' patterns including an additional R wave, notching of the R or S waves, or the presence of more than one fragmentation in two contiguous leads.

RESULTS

In-hospital mortality was higher in PoAF (+) group compared to PoAF (-) group (20.5 vs. 6.4%, P = 0.004). PoAF rate was higher in fQRS (+) group than fQRS (-) group (25.3 vs. 9.8%, P = 0.001). In multivariate analysis, the presence of fQRS complexes on admission ECG [odds ratio (OR) 2.801, 95% confidence interval (CI) 1.262-6.211, P = 0.011) and hemoglobin (OR 0.794; 95% CI, 0.641-0.985; P = 0.036) were identified as independent predictors of PoAF after CABG surgery.

CONCLUSION

The presence of fQRS on admission ECG was found to be an independent predictor of PoAF in patients undergoing isolated CABG.

Perioperative utility of goal-directed therapy in high-risk cardiac patients undergoing coronary artery bypass grafting: "A clinical outcome and biomarker-based study"

Goal-directed therapy (GDT) encompasses guidance of intravenous (IV) fluid and vasopressor/inotropic therapy by cardiac output or similar parameters to help in early recognition and management of high-risk cardiac surgical patients. With the aim of establishing the utility of perioperative GDT using robust clinical and biochemical outcomes, we conducted the present study. This multicenter randomized controlled study included 130 patients of either sex, with European system for cardiac operative risk evaluation ≥3 undergoing coronary artery bypass grafting on cardiopulmonary bypass. The patients were randomly divided into the control and GDT group. All the participants received standardized care; arterial pressure monitored through radial artery, central venous pressure (CVP) through a triple lumen in the right internal jugular vein, electrocardiogram, oxygen saturation, temperature, urine output per hour, and frequent arterial blood gas (ABG) analysis. In addition, cardiac index (CI) monitoring using FloTrac™ and continuous central venous oxygen saturation (ScVO₂) using PreSep™ were used in patients in the GDT group. Our aim was to maintain the CI at 2.5–4.2 L/min/m², stroke volume index 30–65 ml/beat/m², systemic vascular resistance index 1500–2500 dynes/s/cm⁵/m², oxygen delivery index 450–600 ml/min/m², continuous ScVO₂ >70%, and stroke volume variation <10%; in addition to the control group parameters such as CVP 6–8 mmHg, mean arterial pressure 90–105 mmHg, normal ABG values, oxygen saturation, hematocrit value >30%, and urine output >1 ml/kg/h. The aims were achieved by altering the administration of IV fluids and doses of inotropes or vasodilators. The data of sixty patients in each group were analyzed in view of ten exclusions. The average duration of ventilation (19.89 ± 3.96 vs. 18.05 ± 4.53 h, P = 0.025), hospital stay (7.94 ± 1.64 vs. 7.17 ± 1.93 days, P = 0.025), and Intensive Care Unit (ICU) stay (3.74 ± 0.59 vs. 3.41 ± 0.75 days, P = 0.012) was significantly less in the GDT group, compared to the control group. The extra volume added and the number of inotropic dose adjustments were significantly more in the GDT group. The two groups did not differ in duration of inotropic use, mortality, and other complications. The perioperative continuation of GDT affected the early decline in the lactate levels after 6 h in ICU, whereas the control group demonstrated a settling lactate only after 12 h. Similarly, the GDT group had significantly lower levels of brain natriuretic peptide, neutrophil gelatinase-associated lipocalin levels as compared to the control. The study clearly depicts the advantage of GDT for a favorable postoperative outcome in high-risk cardiac surgical patients.

Continuous monitoring of cardiac function by 3-dimensional accelerometers in a closed-chest pig model

OBJECTIVES

Cardiac wall motions reflect systolic and diastolic function. We have previously demonstrated the ability of a miniaturized three-axis (3D) accelerometer to monitor left ventricular function in experimental models and in patients. The main aim of this study was to investigate the clinical utility of the method for monitoring the left and right ventricular function during changes in global and regional cardiac function in a postoperative closed-chest situation.

METHODS

In 13 closed-chest pigs, miniaturized 3D accelerometers were placed on the left ventricle in the apical and basal regions and in the basal region of the right ventricle. An epicardial 3D motion vector was calculated from the acceleration signals in each heart region. Peak systolic velocity along this 3D vector (3D V(sys)) was compared with the positive time derivative of the left and right ventricular pressure and with cardiac index during changes in global LV function (unloading, fluid loading, esmolol, dobutamine) and with ultrasound during regional left ventricular dysfunction (3-min occlusion of the left anterior descending coronary artery).

RESULTS

Significant and typical changes in accelerometer 3D V(sys) were seen in all heart regions during changes in global cardiac function. 3D V(sys) reflected the left and right ventricular contractility via significant correlations with the positive time derivative of the left and right ventricular pressure, r = 0.86 and r = 0.72, and with cardiac index r = 0.82 and r = 0.73 (all P < 0.001), respectively. The miniaturized accelerometers also detected regional dysfunction, but showed reduced ability to localize ischaemia as the 3D V(sys) in all heart regions showed similar reductions during coronary artery occlusion.

CONCLUSIONS

Miniaturized 3D accelerometers placed on the heart can assess global and regional function in a closed-chest model. The technique may be used for continuous postoperative monitoring after cardiac surgery.

Efficacy of prophylactic intra-aortic balloon pump therapy in chronic heart failure patients undergoing cardiac surgery

This study investigated the efficacy of prophylactic intraoperative intra-aortic balloon pump (IABP) usage in chronic heart failure patients with severely reduced left ventricular function undergoing elective cardiac surgery. Between January 2008 and December 2012, 107 patients with severely reduced left ventricular ejection fraction (LVEF <35%) received prophylactic intraoperative IABP implantation during open-heart surgery. Surgical procedures performed were isolated coronary artery bypass grafting (CABG) in 35 patients (32.7%), aortic valve replacement in 12 (11.2%), mitral valve repair or replacement in 15 (14.0%), combined valve and CABG procedures in 27 (25.2%), and other surgical procedures in 18 (16.8%). Results and outcomes were compared with those in a propensity score-matched cohort of 107 patients who underwent cardiac surgery without intraoperative IABP implantation. Matching criteria were age, gender, LVEF, and surgical procedure. Duration of intensive care unit (ICU) stay, duration of hospital stay, and 30-day mortality were markers of outcome. In the IABP group, mean patient age was 69.1 ± 13.7 years; 66.4% (70) were male. All IABPs were placed intraoperatively. Mean duration of IABP application time was 42.4 ± 8.7 h. IABP-related complications occurred in five patients (4.7%), including one case of inguinal bleeding, one case of mesenteric ischemia, and ischemia of the lower limb in three patients. No stroke or major bleeding occurred during IABP support. Mean durations of ICU and hospital stay were 3.38 ± 2.15 days and 7.69 ± 2.02 days, respectively, in the IABP group, and 4.20 ± 3.14 days and 8.57 ± 3.26 days in the control group, showing statistically significant reductions in duration of ICU and hospital stay in the IABP group (ICU stay, P = 0.036; hospital stay, P = 0.015). Thirty-day survival rates were 92.5 and 94.4% in the IABP and control group, respectively, showing no statistically significant difference (P = 0.75). IABP usage in chronic heart failure patients with severely reduced LVEF undergoing cardiac surgery was safe and resulted in shorter ICU and hospital stay but did not influence 7- and 30-day survival rates.

Left ventricular function can be continuously monitored with an epicardially attached accelerometer sensor

OBJECTIVES

Preservation of left ventricular (LV) function is crucial for a beneficial outcome in high-risk patients undergoing cardiac surgery. The present study evaluated a motion sensor (accelerometer) for continuous monitoring of LV performance during changes in global and regional LV function.

METHODS

In 11 pigs, an accelerometer was sutured to the epicardium on the anterior apical LV region. Global LV function was modulated by esmolol, epinephrine and fluid loading, whereas regional LV dysfunction was induced by a 3-min occlusion of left anterior descending (LAD) coronary artery. Epicardial acceleration in the circumferential direction was obtained by the accelerometer, and from this signal, epicardial velocity was calculated. Peak systolic velocity was measured and used as an index of LV performance. The accelerometer was compared with left ventricular stroke work (LVSW), ejection fraction and myocardial strain by echocardiography.

RESULTS

Accelerometer peak systolic velocity and LVSW changed significantly during all interventions, affecting global LV function. Systolic velocity by the accelerometer increased during epinephrine and fluid loading from 14.1 [10.2; 17.3] to 25.4 [16.7; 28.5] (P < 0.05) and 14.8 [12.5; 18.5] cm/s (P < 0.05), respectively. Esmolol infusion significantly decreased accelerometer peak systolic velocity to 9.4 [7.3; 10.7] cm/s (P < 0.05). Minor changes were seen in the echocardiographic measurements, with significant changes only observed in myocardial strain during the interventions with esmolol and epinephrine. Regional LV dysfunction was clearly detected by the accelerometer during LAD occlusion, and peak systolic velocity was reduced from 14.1 [10.2; 17.3] to 5.7 [5.0; 6.8] cm/s (P < 0.05). The accelerometer demonstrated higher sensitivity and specificity for the detection of myocardial ischaemia than LVSW and ejection fraction. For all interventions, accelerometer peak systolic velocity correlated strongly with LVSW (r = 0.81, P < 0.01) and myocardial strain (r = 0.80; P < 0.01).

CONCLUSIONS

It was possible to obtain accurate information on LV performance by the use of an epicardially attached accelerometer. The method allows continuous monitoring of LV function and may therefore improve perioperative monitoring of cardiac surgery patients.

White-matter hyperintensities predict delirium after cardiac surgery

OBJECTIVES

Postoperative delirium is a common psychiatric disorder among patients who undergo cardiac surgery. Although several studies have investigated risk factors for delirium after cardiac surgery, the association between delirium and cerebral white-matter hyperintensities (WMH) on magnetic resonance (MR) imaging has not been previously studied. The aim of this study was to identify general risk factors for delirium, as well as to examine the specific relationship between WMH and delirium.

DESIGN

Retrospective chart review.

SETTING

University hospital.

PARTICIPANTS

A total of 130 patients who underwent cardiac surgery.

MEASUREMENTS

Variables recorded included patient demographics, comorbidities, mental health, laboratory data, surgical information, and cerebrovascular disease. The presence of WMH was assessed using MR images. Two groups of patients were compared (patients with and without delirium) using both univariate and multiple logistic analyses.

RESULTS

Delirium occurred in 18 patients (13.8%) and patients with delirium were significantly older than patients who did not develop delirium. The prevalence of severe WMH (Fazekas score = 3) was significantly higher in patients with delirium. Three independent predictors of delirium were identified: abnormal creatinine (odds ratio [OR]: 4.5; 95% confidence interval [CI]: 1.4-13.9), severe WMH (OR: 3.9; 95% CI: 1.2-12.5), and duration of surgery (OR: 1.4; 95% CI: 1.0-1.8).

CONCLUSIONS

The results of this study suggest that white-matter abnormality is one of the most important risk factors for development of delirium after cardiac surgery. These factors can be used for prediction and prevention of delirium following cardiac surgery.

Hemoglobin and B-type natriuretic peptide preoperative values but not inflammatory markers, are associated with postoperative morbidity in cardiac surgery: a prospective cohort analytic study

Introduction

Risk stratification in cardiac surgery significantly impacts outcome. This study seeks to define whether there is an independent association between the preoperative serum level of hemoglobin (Hb), leukocyte count (LEUCO), high sensitivity C-reactive protein (hsCRP), or B-type natriuretic peptide (BNP) and postoperative morbidity and mortality in cardiac surgery.

Methods

Prospective, analytic cohort study, with 554 adult patients undergoing cardiac surgery in a tertiary cardiovascular hospital and followed up for 12 months. The cohort was distributed according to preoperative values of Hb, LEUCO, hsCRP, and BNP in independent quintiles for each of these variables.

Results

After adjustment for all covariates, a significant association was found between elevated preoperative BNP and the occurrence of low postoperative cardiac output (OR 3.46, 95% CI 1.53–7.80, p = 0.003) or postoperative atrial fibrillation (OR 3.8, 95% CI 1.45–10.38). For the combined outcome (death/acute coronary syndrome/rehospitalization within 12 months), we observed an OR of 1.93 (95% CI 1.00–3.74). An interaction was found between BNP level and the presence or absence of diabetes mellitus. The OR for non-diabetics was 1.26 (95% CI 0.61–2.60) and for diabetics was 18.82 (95% CI 16.2–20.5). Preoperative Hb was also significantly and independently associated with the occurrence of postoperative low cardiac output (OR 0.33, 95% CI 0.13–0.81, p = 0.016). Both Hb and BNP were significantly associated with the lengths of intensive care unit and hospital stays and the number of transfused red blood cells (p < 0.002). Inflammatory markers, although associated with adverse outcomes, lost statistical significance when adjusted for covariates.

Conclusions

High preoperative BNP or low Hb shows an association of independent risk with postoperative outcomes, and their measurement could help to stratify surgical risk. The ability to predict the onset of atrial fibrillation or postoperative low cardiac output has important clinical implications. Our results open the possibility of designing studies that incorporate BNP measurement as a routine part of preoperative evaluation, and this strategy could improve upon the standard evaluation in terms of reducing adverse postoperative events.

Operating room cost for coronary artery bypass graft procedures: does experience or severity of illness matter?

OBJECTIVE

Very few studies have addressed the magnitude of the effect of the condition of the patients and the surgical volume on possible cost savings in coronary artery bypass grafting (CABG). The objectives of this study were to analyse and compare the costs of the CABG operating room (OR) between two hospitals, and to examine the effect of surgical volume and severity of illness on the OR costs.

METHOD

The charts of patients who were diagnosed with coronary artery disease and who underwent CABG at two acute tertiary care hospitals in 2004 were reviewed retrospectively. Data on patient demographics, length of stay (LOS) and the American Society of Anesthesiologists Physical Status (ASAPS) score were extracted from the patient records. Cost information was obtained from detailed billing charges and from the financial accounting divisions of the hospitals.

RESULTS

The high-volume hospital consumed fewer resources than the low-volume hospital (US$5411 vs. US$6407). The age of the patients, surgical volume, operating hours and LOS were associated with the OR cost. Patient age and ASAPS score, hospital, and surgical volume were associated with LOS. Patient age, the number of diseased vessels, doctor volume and pump used or not were positively associated with the operation time. The LOS and the operation time may be the mediators of the relationship between the ASAPS score and cost, and may moderate the association of volume with cost.

CONCLUSIONS

This study supports the saying that 'practice makes perfect'. The knowledge and experience of the surgeons and the hospital management team are equally important in the supply of health services to patients with varying severity of illness, and are needed to maintain the competitive position of a hospital.

Impact of diabetes mellitus on old patients undergoing coronary artery bypass grafting

Few reports have focused on whether old diabetic patients had worse outcomes compared to old nondiabetics after coronary artery bypass grafting (CABG). This study aimed to evaluate the outcomes of old diabetic patients compared to old nondiabetics following isolated CABG. From January 2004 to December 2008, the relevant pre-, intra-, and postoperative materials of all CABG patients over 65 years of age in our center were investigated and analyzed retrospectively. In this study, diabetes is defined as the need for oral medication or insulin. A total of 140 diabetic patients over 65 years of age were entered in the study, accounting for 31.7% of the total population. Diabetic patients over 65 years of age were less likely to have undergone previous percutaneous coronary intervention (P < 0.0001) and more likely to undergo CPB (P = 0.03) during CABG as compared to nondiabetics over 65 years of age. Univariate analysis and multivariate logistic regression analysis showed diabetic patients over 65 years of age only had a higher rate of deep sternal wound infection (OR = 2.76, 95%CI 1.22-7.83, P = 0.002), while sharing almost similar rates among other morbidities and mortality as compared to nondiabetic patients over 65 years of age. Excellent results following CABG may be expected in old diabetic patients.

Family stress, family adaptation, and psychological well-being of elderly coronary artery bypass grafting patients

As our population ages, more elderly patients will undergo coronary artery bypass grafting. The psychological well-being of a patient is influenced by many factors, including family support. This descriptive, correlational pilot study was conducted to examine the relationship between family characteristics and psychological well-being in elderly coronary artery bypass grafting patients. The results of this study, which consists of 42 participants, are presented, as well as implications for critical care nursing.

Coronary artery bypass surgery in high-risk patients

Background

In high-risk coronary artery bypass patients; off-pump versus on-pump surgical strategies still remain a matter of debate, regarding which method results in a lower incidence of perioperative mortality and morbidity. We describe our experience in the treatment of high-risk coronary artery patients and compare patients assigned to on-pump and off-pump surgery.

Methods

From March 2002 to July 2004, 86 patients with EuroSCOREs > 5 underwent myocardial revascularization with or without cardiopulmonary bypass. Patients were assigned to off-pump surgery (40) or on-pump surgery (46) based on coronary anatomy coupled with the likelihood of achieving complete revascularization.

Results

Those patients undergoing off-pump surgery had significantly poorer left ventricular function than those undergoing on-pump surgery (28.6 ± 5.8% vs. 40.5 ± 7.4%, respectively, p < 0.05) and also had higher Euroscore values (7.26 ± 1.4 vs. 12.1 ± 1.8, respectively, p < 0.05). Differences between the two groups were nonsignificant with regard to number of grafts per patient, mean duration of surgery, anesthesia and operating room time, length of stay intensive care unit (ICU) and rate of postoperative atrial fibrillation

Conclusion

Utilization of off-pump coronary artery bypass graft (CABG) does not confer significant clinical advantages in all high-risk patients. This review suggest that off-pump coronary revascularization may represent an alternative approach for treatment of patients with Euroscore ≥ 10 and left ventricular function ≤ 30%.

Significant value of autopsy for quality management in cardiac surgery

OBJECTIVE

With recent advances in diagnostic imaging, the value of autopsy has been called into question. The aim of our study was to assess the current impact of autopsy for early postoperative quality management in cardiac surgery.

METHODS

Between 2000 and 2003, a total of 14,313 patients underwent cardiac surgery at our center. Of these, 898 patients (6.3%) died, and autopsy was performed in 468 cases (52.1%). Data from clinical and postmortem examination were prospectively analyzed regarding causes of death, postoperative complications, concomitant diseases, and surgery-associated pathologic findings.

RESULTS

Mean age was 68.7 years. Mean survival was 13.9 postoperative days. On autopsy, causes of death were cardiac in 49.8% of cases (n = 233), respiratory in 8.3% (n = 39), cerebral in 6.4% (n = 30), abdominal in 4.7% (n = 22), multiorgan failure or sepsis in 14.9% (n = 70), pulmonary embolism in 6.6% (n = 31), procedure associated in 8.3% (n = 39), and others in 0.9% (n = 4). Discrepancies between clinical and postmortem determinations of cause of death were found in 108 cases (23.1%). These were acute myocardial infarction (n = 38), low cardiac output (n = 9), respiratory (n = 8), cerebral (n = 5), abdominal (n = 7), multiorgan failure or sepsis (n = 12), pulmonary embolism (n = 18), and procedure associated (11). Clinically unrecognized postoperative complications were found in 364 cases (77.8%). Unknown concomitant diseases were found in 464 cases (99.1%), with potential therapeutic relevance in 90 cases (19.2%). In 85 cases (18.2%), autopsy examination revealed 96 premortem unrecognized surgery-associated pathologic findings.

CONCLUSION

A high overall discrepancy rate between premortem and autopsy diagnoses was recognized. Autopsy revealed clinically relevant information in a significant number of cases. Therefore autopsy remains essential for quality assessment in perioperative treatment.

High risk coronary artery bypass patient: incidence, surgical strategies, and results

BACKGROUND

To describe our experience in the treatment of high risk coronary artery bypass patients and compare patients assigned to on-pump or off-pump surgery.

METHODS

During a 42-month period 306 high risk (Euroscore > 5) coronary artery bypass patients were consecutively treated at our institution. On the basis of the coronary anatomy and possibility of achieving a complete revascularization, 197 patients were assigned to off-pump and 109 to on-pump operation. Overall mortality was 6.2% (19 of 306 patients).

RESULTS

Although patients treated off-pump had a better cardiac status, no clinical advantages related to the avoidance of cardiopulmonary bypass were found in the overall population. Off-pump patients had more early and late cardiac complications, whereas patients operated on-pump exhibited an higher incidence of postoperative systemic organ dysfunction. Off-pump surgery improved in-hospital outcome only in the subset of patients at highest risk.

CONCLUSIONS

Avoidance of cardiopulmonary bypass does not confer significant clinical advantages in all high risk coronary patients; instead, there are particular subsets of patients in whom beating heart surgery can be particularly indicated and others for whom on-pump revascularization appears a better solution. Adaptation of the operation to the single patient is probably the way to improve outcome.

Hospital coronary artery bypass graft surgery volume and patient mortality, 1998-2000

OBJECTIVE

To evaluate the association between annual hospital coronary artery bypass graft (CABG) surgery volume and in-hospital mortality.

SUMMARY BACKGROUND DATA

The Leapfrog Group recommends health care purchasers contract for CABG services only with hospitals that perform >or=500 CABGs annually to reduce mortality; it is unclear whether this standard applies to current practice.

METHODS

We conducted a retrospective analysis of the National Inpatient Sample database for patients who underwent CABG in 1998-2000 (n = 228738) at low (12-249 cases/year), medium (250-499 cases/year), and high (>or=500 cases/year) CABG volume hospitals. Crude in-hospital mortality rates were 4.21% in low-volume hospitals, 3.74% in medium-volume hospitals, and 3.54% in high-volume hospitals (trend P < 0.001). Compared with patients at high-volume hospitals (odds ratio 1.00, referent), patients at low-volume hospitals remained at increased risk of mortality after multivariable adjustment (odds ratio 1.26, 95% confidence interval = 1.15-1.39). The mortality risk for patients at medium-volume hospitals was of borderline significance (odds ratio 1.11, 95% confidence interval = 1.01-1.21). However, 207 of 243 (85%) of low-volume and 151 of 169 (89%) of medium-volume hospital-years had risk-standardized mortality rates that were statistically lower or comparable to those expected. In contrast, only 11 of 169 (6%) of high-volume hospital-years had outcomes that were statistically better than expected.

CONCLUSIONS

Patients at high-volume CABG hospitals were, on average, at a lower mortality risk than patients at lower-volume hospitals. However, the small size of the volume-associated mortality difference and the heterogeneity in outcomes within all CABG volume groups suggest individual hospital CABG volume is not a reliable marker of hospital CABG quality.

Predictors of delirium after cardiac surgery delirium: Effect of beating-heart (off-pump) surgery

BACKGROUND

Despite improved outcomes after cardiac operations, postoperative delirium remains a common complication that is associated with increased morbidity and prolonged hospital stay.

METHODS

Univariate and multivariate predictors of postoperative delirium were determined from prospectively gathered data on 16,184 patients undergoing cardiac operations with cardiopulmonary bypass (conventional, n = 14,342) and without cardiopulmonary bypass (beating-heart surgery, n = 1847) between April 1996 and August 2001. Delirium was defined as a transient mental syndrome of acute onset characterized by global impairment of cognitive functions, a reduced level of consciousness, attentional abnormalities, increased or decreased psychomotor activity, and a disordered sleep-wake cycle.

RESULTS

The overall prevalence of postoperative delirium was 8.4%. Of 49 selected patient-related risk factors and treatment variables, 35 were highly associated with postoperative delirium by univariate analysis. Stepwise logistic regression revealed the following variables as independent predictors of delirium: history of cerebrovascular disease, peripheral vascular disease, atrial fibrillation, diabetes mellitus, left ventricular ejection fraction of 30% or less, preoperative cardiogenic shock, urgent operation, intraoperative hemofiltration, operation time of 3 hours or more, and a high perioperative transfusion requirement. Two variables were identified as having a significant protective effect against postoperative delirium: beating-heart surgery and younger patient age.

CONCLUSIONS

Postoperative delirium is a common complication in cardiac operations. The increased use of beating-heart surgery without cardiopulmonary bypass may lead to a lower prevalence of this complication and thus improve patient outcomes.

Decreasing significance of left ventricular dysfunction and reoperative surgery in predicting coronary artery bypass grafting–associated mortality: A twelve-year study

OBJECTIVES

Patients undergoing coronary artery bypass grafting are older and have greater comorbidity than those operated on previously. We evaluated the changes in the predictors of in-hospital mortality among patients undergoing coronary artery bypass grafting during the last 12 years.

METHODS

Data on demographic characteristics, preoperative risk factors, operative variables, and hospital outcomes were collected prospectively for all patients undergoing isolated coronary artery bypass grafting at a single institution from January 1, 1990, to December 31, 2001. To examine the effect of time on patient risk profiles and outcomes, we divided patients into three groups according to year of operation (1990-1993 n = 5171, 1994-1997 n = 5977, 1998-2001 n = 6893).

RESULTS

In-hospital mortality declined from 2.4% (1990-1993) to 1.2% (1998-2001, P <.0001). Left ventricular dysfunction, increasing age, female gender, hypertension, diabetes, cardiogenic shock, congestive heart failure, peripheral vascular disease, reoperative coronary artery bypass grafting, left main disease, and urgent surgery independently predicted in-hospital mortality in the entire cohort of 18,041 patients. Severe left ventricular dysfunction was the most significant predictor of in-hospital mortality in the 12-year cohort, but it had a declining influence with time (1990-1993 odds ratio 7.1, 1994-1997 odds ratio 5.1, 1998-2001 not statistically significant) because of improving outcomes. Reoperative coronary artery bypass grafting similarly decreased in significance as a predictor of mortality. Emergency coronary artery bypass grafting was performed less frequently in recent years, but the requirement for emergency surgery carried an increasing odds ratio for mortality.

CONCLUSIONS

Despite increasing patient age and comorbidity, improvements in perioperative management have reduced the significance of severe left ventricular dysfunction and reoperative coronary artery bypass grafting but not emergency surgery as predictors of in-hospital mortality.

Predictors of prolonged ICU stay after on-pump versus off-pump coronary artery bypass grafting

OBJECTIVE

To define predictors for prolonged ICU stay in order to improve patient outcome and reduce costs.

PATIENTS AND METHODS

Prospective data on 10,759 patients undergoing coronary artery bypass grafting with and without use of cardiopulmonary bypass (coronary artery bypass grafting, CABG; n =8,917; off-pump coronary artery bypass grafting, OPCAB; n =765; minimally invasive direct coronary artery bypass grafting, MIDCAB; n =1,077) between April 1996 and August 2001 were subjected to univariate and, consecutively, to multivariate logistic regression analysis. Prolonged ICU stay was defined as intensive care treatment for three postoperative days and longer.

MEASUREMENTS AND RESULTS

Mean duration of ICU stay was 3.8+/-6.9 days; overall prevalence of prolonged ICU stay was 37.1%. The hospital mortality was 3.5% (ICU > or =3 days: 5.9%; ICU <3 days: 2.0%). Out of 39 selected pre- and intraoperative patient- and treatment-related variables, by univariate analysis, 32 variables having a high association with prolonged ICU stay were identified. Using a stepwise logistic regression model, 20 variables were shown to be independent predictors for prolonged ICU stay. Both OPCAB and MIDCAB surgery were identified as having a significantly lower association with prolonged ICU stay.

CONCLUSION

As prolonged ICU stay is associated with poor patient outcome and increased costs it is of utmost importance to identify patients at a high risk for prolonged ICU stay. More frequent off-pump CABG may optimize patient outcome.

Can EuroSCORE predict direct costs of cardiac surgery?

OBJECTIVE

The aim of this study is to determine if a preoperative risk stratification model can identify different surgical costs.

METHODS

Four hundred and eighty-eight patients undergoing open heart surgery between March 2000 and March 2001 were classified with the EuroSCORE model. Direct variable costs were prospectively collected, surgical team costs excluded. The multivariate analysis was used to find variables independently associated with costs.

RESULTS

Of the 488 patients enrolled 342 (70%) were males, mean age 65+/-10 years, 57 (12%) had myocardial infarction, 20 (4%) had ejection fraction <30%, 56 (11%) were operated in emergency, 26 (5%) had a re-operation. 113 (23.2%) were operated for valvular disease, 30 (6.1%) were operated for thoracic aortic surgery, one (0.2%) was operated for interatrial septal defect, 79 (16.2%) were operated for other intervention in addition to coronary bypass and 265 (54.3%) for isolated coronary bypass. The mean intensive care unit length of stay (ICU-LOS) was 2.3+/-4.1 days and the postoperative LOS was 8.2+/-5.3 days. According to EuroSCORE, 117 patients (24%) were at low, 187 (38%) at medium, and 184 (38%) at high risk. Costs were significantly and directly correlated with preoperative risk model with a correlation coefficient of 0.47 and an increase of costs of 3.5% (95% CI 2.3-4.7, P<0.0001) for each single rise of risk score. The relationship EuroSCORE vs. direct costs is, respectively: EuroSCORE 0-2 ==> 6863+/-861 Euro; 3-4 ==> 8292+/-3714 Euro; 5-6 ==> 8908+/-3480 Euro; 7-8 ==> 10,462+/-6123 Euro; 9-10 ==> 13,711+/-12,634 Euro; >10 ==> 21,353+/-18,507 Euro. Excluding EuroSCORE from the preoperative logistic model, age, preoperative creatinine, critical condition, ejection fraction, re-operation and sex were independently correlated with costs.

CONCLUSIONS

From our data the EuroSCORE model developed to predict (30-day postoperative) hospital mortality could be used to predict direct operative costs and identify patients with different levels of resource consumption.

Long-term clinical outcome of coronary artery stenting in elderly patients

BACKGROUND

The elderly constitute a rapidly expanding segment of our population and cardiovascular disease becomes more prevalent with increasing age. Existing data have shown that percutaneous coronary interventions in the elderly are associated with an increase risk of in-hospital complications compared to younger patients. In the present study we retrospectively assessed the long-term clinical outcome of coronary artery stenting in an elderly population and compared them with the cohort of younger patients.

METHODS

The study population included 402 consecutive patients with coronary artery disease who underwent coronary artery stenting; of these 69 were elderly (age > 70 years, group I) and 333 were younger (age <or= 70 years, group II). Percutaneous coronary intervention combined with stent implantation was performed using standard techniques. Clinical outcomes during follow-up (24 +/- 13 months, range 7-56 months) were obtained in all patients without major in-hospital complications. Survival curves and multivariate Cox proportional hazard models for any late clinical event were reported.

RESULTS

No difference in in-hospital complications or clinical success rate was observed between the two groups of patients. Complete revascularization was obtained more frequently in younger compared to elderly patients (P < 0.05). At 2 years, event-free survival was 62% in the elderly and 76% in younger patients (P < 0.001); this difference was mostly made-up by recurrence of angina in the elderly. Impaired left ventricular systolic function (ejection fraction < 40%) was an independent predictor of late death.

CONCLUSIONS

Coronary artery stenting is an effective therapeutic strategy in elderly with coronary artery disease and is associated with good short- and long-term results. Age per se should not preclude patients from undergoing coronary stenting.

Limited-access surgical coronary artery revascularization

The continued evolution of surgical revascularization has resulted in much less invasive alternatives for patients undergoing coronary artery bypass grafting. In particular, techniques and technologies have been developed to allow for the grafting of coronary arteries through limited access incisions without the circulatory support of cardiopulmonary bypass. The conduits are generally arterial rather than the venous alternatives used originally, and the harvesting of these conduits is performed through limited access incisions described in another article in this review. The result of these efforts is sternal-sparing solutions for the off-pump coronary artery bypass grafting of all the various coronary locations on the heart. This is accomplished through a spectrum of small incisions that can directly expose any specific area of interest for focal bypass grafting. The surgical insult is greatly reduced and the patient's recovery is significantly enhanced. These efforts continue to bring us closer to the ultimate goal of 24-hour hospital stays for coronary artery bypass grafting patients.

Cardiac surgery report cards: comprehensive review and statistical critique

Public report cards and confidential, collaborative peer education represent distinctly different approaches to cardiac surgery quality assessment and improvement. This review discusses the controversies regarding their methodology and relative effectiveness. Report cards have been the more commonly used approach, typically as a result of state legislation. They are based on the presumption that publication of outcomes effectively motivates providers, and that market forces will reward higher quality. Numerous studies have challenged the validity of these hypotheses. Furthermore, although states with report cards have reported significant decreases in risk-adjusted mortality, it is unclear whether this improvement resulted from public disclosure or, rather, from the development of internal quality programs by hospitals. An additional confounding factor is the nationwide decline in heart surgery mortality, including states without quality monitoring. Finally, report cards may engender negative behaviors such as high-risk case avoidance and "gaming" of the reporting system, especially if individual surgeon results are published. The alternative approach, continuous quality improvement, may provide an opportunity to enhance performance and reduce interprovider variability while avoiding the unintended negative consequences of report cards. This collaborative method, which uses exchange visits between programs and determination of best practice, has been highly effective in northern New England and in the Veterans Affairs Administration. However, despite their potential advantages, quality programs based solely on confidential continuous quality improvement do not address the issue of public accountability. For this reason, some states may continue to mandate report cards. In such instances, it is imperative that appropriate statistical techniques and report formats are used, and that professional organizations simultaneously implement continuous quality improvement programs. The statistical methodology underlying current report cards is flawed, and does not justify the degree of accuracy presented to the public. All existing risk-adjustment methods have substantial inherent imprecision, and this is compounded when the results of such patient-level models are aggregated and used inappropriately to assess provider performance. Specific problems include sample size differences, clustering of observations, multiple comparisons, and failure to account for the random component of interprovider variability. We advocate the use of hierarchical or multilevel statistical models to address these concerns, as well as report formats that emphasize the statistical uncertainty of the results.

Relationship of hospital size, case volume, and cost for coronary artery bypass surgery: analysis of 12,774 patients operated on in Massachusetts during fiscal years 1995 and 1996

OBJECTIVE

This study investigates the relationship between the cost of coronary artery bypass graft surgery and both hospital size and case volume.

METHODS

Retrospective administrative and cost data were obtained for all 12,774 patients who underwent isolated coronary bypass surgery at 12 Massachusetts hospitals during 1995 and 1996. Hospitals were stratified by number of operating beds into 3 groups (group I, <250 beds; group II, 250-450 beds; group III, >450 beds). Total (diagnosis-related groups 106 + 107) annual coronary bypass cases per hospital varied from 271 to 913 (mean 532). Univariate and multivariable analyses were used to study the relationship between the direct and total cost and a number of patient (age, sex, acuity class, payer) and hospital (bed capacity, annual case volume per diagnosis-related group, cardiothoracic residency) predictor variables. For each hospital, we also studied the relationship between changes in coronary bypass case volume and the corresponding changes in average cost from 1995 to 1996.

RESULTS

Scatterplots revealed a broad range of mean direct cost of coronary bypass surgery among hospitals with comparable case volumes. When annual cases were analyzed as continuous variables, there was no linear relationship of case volume with direct or total cost of coronary bypass (r = -0.05 to +0.08) for any diagnosis-related group or year. When hospital bed capacity and case volume were grouped into strata and studied by analysis of variance, there was no evidence of an inverse relationship between these variables and cost. In multivariable analysis, patient acuity class and diagnosis-related group were the most important predictors of cost. Beds and case volume met inclusion criteria for most models but added little to the "explanation" of variability R(2), often less than 1%. Finally, substantial interhospital differences were noted in the magnitude and direction (direct vs inverse) of their 1995 to 1996 change in volume versus change in cost.

CONCLUSIONS

Within the range of hospital size and case volume represented in this study, there is no evidence that either variable is related to the cost of performing coronary bypass surgery. Massachusetts hospitals appear to function on different segments of different average cost curves. It is not possible to predict the relative cost of coronary bypass grafting at a given hospital based primarily on volume.

Rapid recovery protocol applied to 5,658 consecutive "on-pump" coronary bypass patients

BACKGROUND

Increasing hospital costs, restricted resources, and new surgical strategies have stimulated effectiveness of all routines in cardiac surgery. Over a 10-year period, 5,658 consecutive patients undergoing coronary artery bypass grafting followed a protocol aiming at short postoperative intubation times and rapid physical rehabilitation.

METHODS

The patients were prepared for rapid recovery, emphasizing (1) preoperative education and respiratory training, (2) low-dose fentanyl anesthesia, (3) limited ischemic times and pump times, (4) mild hypothermia and rewarming to a rectal temperature of 36 degrees C, (5) restricted use of extended monitoring, (6) autologous blood salvage to avoid allogeneic blood transfusions, and (7) active physical training from postoperative day 1. All in-hospital data relevant to these steps were prospectively stored in a database.

RESULTS

The median extubation time after arrival in the intensive care unit was 1.5 hours (0 to 320 hours). More than 99% of the patients were extubated within 5 hours. Sixty-two patients (1.1%) were reintubated and ventilated for a median of 24 hours (1 to 430 hours), mostly due to resternotomy for bleeding or cardiopulmonary decompensation. In total, 5,594 patients (98.9%) were able to sit in a chair the first postoperative day. Within the fourth postoperative day, 82.5% were able to move freely in the hospital area and were in fact physically fit for hospital discharge. Allogeneic blood products were given to 3.9% of the patients. Twenty-three patients (0.41%) died in-hospital.

CONCLUSIONS

With the application of a protocol for rapid physical recovery in patients undergoing "on-pump" coronary artery bypass grafting, extubation within 1 to 2 hours was safe and feasible in most patients. After 5 hours, 99.3% of the patients were extubated, with a reintubation rate of 1.1%. More than 80% of the patients were fully physically mobile within 4 days after the operation.

Ten-year trends in heart valve replacement operations

BACKGROUND

There has been increasing concern in recent years about the quality and cost of heart valvular replacement procedures. The purpose of this study is to examine the profile of patients undergoing valvular operations during the past decade, and to look at trends in outcome and resource utilization over that period.

METHODS

Clinical and procedural data of 2,972 patients undergoing heart valve replacement at Emory University Hospitals between 1988 and 1997 were recorded prospectively on standardized forms by trained medical personnel and entered into a computerized database.

RESULTS

There were 1,802 patients undergoing aortic valve replacement (AVR), 966 undergoing mitral valve replacement (MVR), and 204 undergoing combined aortic and mitral valve procedures (AVR + MVR). No patients were excluded. There was a statistically significant trend for patients undergoing AVR, MVR, or AVR + MVR over time to be older and sicker by multiple criteria. Nonetheless, procedural outcome and inhospital mortality for patients undergoing AVR remained unchanged. Cost and length of stay increased from 1988 to 1992 when a concerted effort to decrease resource utilization began. Between 1992 and 1997 for AVR, length of stay decreased from 13.4 to 8.0 days and cost from $37,047 to $21,856. Similarly, between 1992 and 1997 for MVR, length of stay decreased from 15.6 to 8.1 days and cost from $45,072 to $21,747. The net result over the time period from 1988 to 1997 was an average decline in the cost of operation of $785 a year, adjusted for other factors.

CONCLUSIONS

This study reveals that outcome of valvular replacement during the period from 1988 to 1997 has remained constant despite the patients becoming older and sicker during the same period. This constant outcome has been accomplished, but length of stay has decreased significantly. Hospital costs increased during the first years of the study period, but then decreased to levels in 1997 that were equal to or significantly less than 1988 levels.

[The practical clinical guidelines of the Sociedad Española de Cardiología on coronary surgery]

Surgery in coronary disease, including myocardial revascularization and the surgery of mechanical complications of acute myocardial infarction, has shown to improve the symptoms, quality of life and/or prognosis in certain groups of patients. The expected benefit in each patient depend on many well-known factors among which the appropriateness of the indication for surgery is fundamental. The objective of these guidelines is to review current indications for cardiac surgery in patients with coronary heart disease through an evaluation of the degree of evidence of effectiveness in the light of current knowledge (systematic review of bibliography) and expert opinion gathered from various reports. Indications and the degree of recommendation for conventional coronary artery bypass grafting have been established for each of the most frequent anatomo-clinical situations defined by clinical symptoms (stable angina, unstable angina and acute myocardial infarction) as well as by left ventricular function and extend of coronary disease. Furthermore, the subgroups with the greatest surgical risk and stratification models are described to aid the decision making process. Also we analyse the rational basis and indication for the new surgical techniques such as minimally invasive coronary surgery and total arterial revascularization. Finally, the indication and timing of surgery in patients with mechanical complications of acute myocardial infarction are considered.

Evaluation of the inner-surface morphology of an artificial heart by acoustic microscopy

The total artificial heart (TAH) is being developed for permanent replacement of the natural heart instead of heart transplantation. The need for detecting the material fatigue in the TAH is increasing in order to guarantee long-term use. In this study, the inner surface morphology of the TAH was evaluated by a specially developed scanning acoustic microscope (SAM) system operating in the frequency range of 100-200 MHz. The inner sac of our TAH consisted of polyvinylchloride coated with polyurethane, and the SAM investigations were performed before and after the implantations in goats. The amplitude images of the SAM demonstrated protein adhesion on the inner surface of the TAH after the animal experiment, and the phase images showed distortion of the wall with spatial resolution of 0.2 microm. These results suggest the feasibility of a high-frequency ultrasound for evaluating the material fatigue of TAH.

Improved outcome of APACHE II score-defined escalating systemic inflammatory response syndrome in patients post cardiac surgery in 1996 compared to 1988-1990: the ESSICS-study pilot project

OBJECTIVE

Cardiac surgery using extracorporeal circulation leads to the release of cytokines and subsequently to a systemic inflammatory response syndrome, which is thought to be a negative prognostic factor for patients' outcome. A stratification for the risk of an escalating systemic inflammatory response syndrome had been achieved in a monocenter study carried out in 1988-1990, using APACHE II scoring on the morning of the 1st postoperative day. We now re-evaluated this concept prospectively in three independent centers.

METHODS

The APACHE II based risk stratification was put to test in three independent heart surgery centers in the period from June to December 1996. Nine hundred and forty-five patients after elective cardiac surgery (excluding heart transplantation) with the assistance of the cardiopulmonary bypass were prospectively monitored.

RESULTS

We found an increase in mortality with higher APACHE II score values determined on the 1st postoperative day. The mortality rose to nearly 50% with an APACHE II score of > or = 28. Patients at high risk for the development of a systemic inflammatory response syndrome (APACHE II score > or = 24) significantly differed from patients at lower risk (APACHE II score < 19) in the duration of mechanical ventilation and extracorporeal circulation, age and New York Heart Association (NYHA) classification (P < 0.05).

CONCLUSION

The APACHE II score determined on the morning of the 1st postoperative day helps identifying the subgroup of patients with escalating systemic inflammatory response syndrome. Comparison with the data obtained in the years 1988-1990, suggests a better prognosis in the current trial for patients at high risk with a similar degree of escalating systemic inflammatory response syndrome.

Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients

OBJECTIVE

To assess risk factors for mortality in cardiac surgical adult patients as part of a study to develop a European System for Cardiac Operative Risk Evaluation (EuroSCORE).

METHODS

From September to November 1995, information on risk factors and mortality was collected for 19030 consecutive adult patients undergoing cardiac surgery under cardiopulmonary bypass in 128 surgical centres in eight European states. Data were collected for 68 preoperative and 29 operative risk factors proven or believed to influence hospital mortality. The relationship between risk factors and outcome was assessed by univariate and logistic regression analysis.

RESULTS

Mean age (+/- standard deviation) was 62.5+/-10.7 (range 17-94 years) and 28% were female. Mean body mass index was 26.3+/-3.9. The incidence of common risk factors was as follows: hypertension 43.6%, diabetes 16.7%, extracardiac arteriopathy 2.9%, chronic renal failure 3.5%, chronic pulmonary disease 3.9%, previous cardiac surgery 7.3% and impaired left ventricular function 31.4%. Isolated coronary surgery accounted for 63.6% of all procedures, and 29.8% of patients had valve operations. Overall hospital mortality was 4.8%. Coronary surgery mortality was 3.4% In the absence of any identifiable risk factors, mortality was 0.4% for coronary surgery, 1% for mitral valve surgery, 1.1% for aortic valve surgery and 0% for atrial septal defect repair. The following risk factors were associated with increased mortality: age (P = 0.001), female gender (P = 0.001), serum creatinine (P = 0.001), extracardiac arteriopathy (P = 0.001), chronic airway disease (P = 0.006), severe neurological dysfunction (P = 0.001), previous cardiac surgery (P = 0.001), recent myocardial infarction (P = 0.001), left ventricular ejection fraction (P = 0.001), chronic congestive cardiac failure (P = 0.001), pulmonary hypertension (P = 0.001), active endocarditis (P = 0.001), unstable angina (P = 0.001), procedure urgency (P = 0.001), critical preoperative condition (P = 0.001) ventricular septal rupture (P = 0.002), noncoronary surgery (P = 0.001), thoracic aortic surgery (P = 0.001).

CONCLUSION

A number of risk factors contribute to cardiac surgical mortality in Europe. This information can be used to develop a risk stratification system for the prediction of hospital mortality and the assessment of quality of care.

Improvement in quality of life differs between women and men after coronary artery bypass surgery

OBJECTIVE

To study improvement in quality of life (QoL) after coronary artery bypass grafting (CABG) in relation to gender.

BACKGROUND

Women generally report worse QoL after CABG than men. However, women are older and more symptomatic prior to surgery, which should be considered in comparative analyses.

METHODS

We studied consecutive patients who underwent CABG between 1988 and 1991 [n = 2121] with a QoL questionnaire containing the Physical Activity Score, the Nottingham Health Profile and the Psychological General Well-being Index prior to, 3 months, 1 year and 2 years after surgery.

RESULTS

Females were older than men with more concomitant diseases preoperatively. QoL was improved on all postoperative occasions for both sexes. Improvement in the Physical Activity Score was somewhat, although not significantly, greater in males. Improvement in the Nottingham Health Profile was greater in females. General well-being showed no consistent pattern for improvement.

CONCLUSIONS

QoL is significantly improved after CABG in both sexes throughout follow-up. There is a complex association between improvement in various aspects of QoL and gender.