Comparison of short-term mortality risk factors for valve replacement versus coronary artery bypass graft surgery

Targeted temperature management in cardiac surgery: a systematic review and meta-analysis on postoperative cognitive outcomes

BACKGROUND

Postoperative cognitive decline occurs commonly after cardiac surgery. The available literature is inconclusive on the role of intraoperative causal or protective factors.

METHODS

We systematically reviewed studies evaluating delayed neurocognitive recovery (DNR), postoperative neurocognitive disorder (NCD), stroke, and the mortality rates among patients undergoing hypothermic or normothermic cardiopulmonary bypass (CPB). We further performed a subgroup analysis for age, surgery type (coronary artery bypass grafting [CABG], valve surgery, or combined), and the mean arterial blood pressure (MAP) during CPB, and conducted a proportion meta-analysis after calculation of single proportions and confidence intervals (CIs).

RESULTS

We included a total of 58 studies with 9609 patients in our analysis. Among these, 1906 of 4010 patients (47.5%) had DNR, and 2071 of 7160 (28.9%) had postoperative NCD. Ninety of 4625 patients (2.0%) had a stroke, and 174 of 7589 (2.3%) died. There was no statistically significant relationship between the considered variables and DNR, NCD, stroke, and mortality. In the subgroup analysis comparing hypothermic with normothermic CPB, we found higher NCD rates after combined surgery; for normothermic CPB cases only, the rates of DNR and NCD were lower after combined surgery compared with CABG surgery. A MAP >70 mm Hg compared with MAP=50-70 mm Hg during CPB was associated with a lower rate of DNR.

CONCLUSIONS

Temperature, MAP during cardiopulmonary bypass age, and surgery type were not associated with neurocognitive disorders, stroke, and mortality in cardiac surgery. Normothermic cardiopulmonary bypass, particularly when performed with MAP >70 mm Hg, may reduce the risk of postoperative neurocognitive decline after cardiac surgery.

PROSPERO REGISTRATION NUMBER

CRD42019140844.

Cardiovascular Risk Factors in Coronary Artery Bypass Graft Patients: Comparison Between Two Periods

Background

Information showing risk factor trends in patients undergoing coronary artery bypass graft in Saudi Arabia is scarce. Thus, we aimed to compare cardiovascular risk factors among coronary artery bypass graft patients between two periods: 2012 and 2018.

Methods

This was a cross-sectional study based on hospital records at a tertiary center in Saudi Arabia. The medical records of 72 patients in 2012 and 111 patients in 2018 were reviewed. The study included all patients who underwent coronary artery bypass grafting for the first time. The chi-square test and independent t-test were used for statistical analysis; P-values less than 0.05 were considered statistically significant.

Results

The mean (SD) of the patient age was 61.21 (9.74) years in the first period and 58.01 (11.14) years in the second period. The number of patients who smoked was significantly higher in the second period of the study (14.3% in the first period; 27.0% in the second period; P < 0.001). The study also showed an increase in hypertension and diabetes mellitus in the second period compared to the first (70% vs 71.2% and 68.6% vs 72.1%, respectively), and a reduction in the percentage of patients with hypercholesterolemia (18.3% vs 17.1%). However, these findings were non-significant.

Conclusions

The percentage of smokers was significantly higher in the second period of this research as a consequence of cultural variation and because of the popularity of water-pipe smoking in the society. We recommend the need for increased awareness regarding smoking and the implementation of smoking-cessation programs.

Relationship among Mortality of Patients with Acute Kidney Injury after Cardiac Surgery, Fluid Balance and Ultrafiltration of Renal Replacement Therapy: An Observational Study

Background/Aims: The study aimed to investigate the relationship among mortality of patients with cardiac surgery-associated acute kidney injury (CSA-AKI), fluid balance, and ultrafiltration of renal replacement therapy (RRT). Methods: From January 2009 to October 2015, hospitalized patients with CSA-AKI receiving continuous or prolonged intermittent RRT were screened. The effects of fluid balance and ultrafiltration of RRT on clinical outcome were analyzed. Results: The 30-day mortality of all the 63 patients in the study was 58.6%. Compared with the death group, the survival group had a significantly lower fluid balance, larger ultrafiltration volume, and similar ultrafiltration rate during the first 3 days of RRT. Multivariate Cox regression analysis revealed that positive fluid balance during the first day of RRT, cardiac function of grade IV, and higher Sequential Organ Failure Assessment score were independent risk factors of 30-day mortality. Conclusion: Fluid balance was more relevant to short-term prognosis of CSA-AKI-RRT patients than ultrafiltration volume or ultrafiltration rate.

[EuroSCORE underestimate the mortality risk in cardiac valve surgery of Mexican population]

OBJECTIVE

The EuroSCORE (European System for cardiac operative risk evaluation) stratifies cardiac risk surgery in easy and accessible manner; it was validated in North America with good results but in many countries of Latin America is used routinely without prior validation. Our objective was to validate the EuroSCORE in patients with cardiac valve surgery at the Instituto Nacional de Cardiología Ignacio Chávez (INCICh) in México.

METHODS

EuroSCORE additive and logistic models were used to predict mortality in adults undergoing cardiac valve surgery from march 2004 to march 2008. The goodness of fit test of Hosmer-Lemeshow was used to evaluate the calibration. The area under the ROC curve was calculated to determinate discrimination.

RESULTS

We included 1188 patients with ages of 51.3±14.5 years, 52% women. There were significant differences in the prevalence of risk factors among the INCICh and the EuroSCORE populations. Total mortality was 9.68% versus 5% and 5.6% predicted by additive and logistic EuroSCORE. According to additive EuroSCORE the risk was low in 11.3%, intermediate in 52.9% and high in 35.9%; for these groups the mortality was .7%, 6.34% and 17.4% against those predicted of 2%, 3.9% and 7.64%. Hosmer-Lemeshow test had a P<.001 for both models and the area under the ROC curve was .707 and .694 for additive and logistic EuroSCORE.

CONCLUSION

In the INCICh 88.7% of patients with cardiac valve surgery had intermediate to high risk and EuroSCORE underestimated the risk of mortality.

The EuroSCORE: a neglected measure of medium-term survival following cardiac surgery

OBJECTIVES

EuroSCORE is used to predict operative mortality following cardiac surgery. There are limited data to assess the ability of EuroSCORE to predict medium- to long-term survival. We aimed to test the ability of EuroSCORE to predict mid-term survival following cardiac surgery.

METHODS

We analysed prospectively collected data from all patients undergoing cardiac surgery in an urban tertiary cardiac centre over a 6-year period. All-cause mortality following cardiac surgery was determined via Office of National Statistics data. Patients were grouped into all comers, coronary artery bypass graft (CABG), isolated aortic valve replacement (AVR), isolated mitral valve repair and replacement (MVR) and combined AVR/MVR and CABG. Each group was separated into EuroSCORE quartiles. Kaplan-Meier curves were used to calculate 6-year actuarial survival. Log-rank test was used to calculate the P-value. C-statistic discriminated the ability of the EuroSCORE to predict medium-term survival.

RESULTS

A total of 9022 consecutive patients were identified. The mean age was 66.86 years, 73.7% were male. The cases were grouped according to their additive EuroSCORE into 0-5 (n = 5369), 6-10 (n = 3059), 11-15 (n = 506) and >15 (n = 93). Median follow-up was 2.92 years. The 6-year survival was 88.5, 71.8, 52.5 and 39.5%, respectively. The P-value for all operative categories was significant. The C-statistic was 0.68 (all comers), 0.72 for isolated MVR, 0.65 (isolated CABG), 0.62 (isolated AVR) and 0.69 (combined AVR/MVR and CABG).

CONCLUSIONS

Additive EuroSCORE may be used to predict medium-term survival in patients undergoing cardiac surgery; increasing additive EuroSCORE resulting in significant decreases in survival. It is a good predictive tool for patients undergoing isolated MVR and a fair tool for patients undergoing the remaining operative procedures studied.

Operative treatment of combined aortic stenosis and coronary artery disease

Introduction:

The aortic valve replacement is a standard operating procedure in patients with severe aortic stenosis. Structure of patients undergoing surgery ranges from young population with isolated mitral valvular disease to the elderly population, which is in addition to the underlying disease additionally burdened with comorbidity. One of the most commonly present factors that further complicate the surgery is coronary heart disease that occurs in, almost, one third of patients with aortic stenosis. The aim is to compare the results of surgery for aortic valve replacement with or without coronary artery bypass graft (CABG).

Patients and Methods:

From August 2008 to January 2013 in our center operated on 120 patients for aortic stenosis. Of this number, 75 were men and 45 women. The average age was 63.37 years (16-78). Isolated aortic valve replacement was performed in 89 patients and in 31 patients underwent aortic valve replacement and coronary bypass surgery. Implanted 89 biological and 31 mechanical valves.

Results:

Patients with associated aortic stenosis and coronary artery disease were more expressed symptomatic symptoms preoperatively to patients with isolated aortic stenosis who were on average younger age. Intra-hospital morbidity and mortality was more pronounced in the group of patients with concomitant aortic valve replacement and coronary bypass surgery. Morbidity was recorded in 17 patients (14.3%) in both groups, while the mortality rate in both groups was 12 patients (10.1%).

Conclusion:

Evaluation of preoperative risk factors and comorbidity in patients with aortic stenosis and coronary artery disease contributes to a significant reduction in intraoperative and postoperative complications. Also, early diagnosis of associated coronary artery disease and aortic stenosis contributes to timely decision for surgery thus avoiding subsequent ischaemic changes and myocardial damage.

Coronary artery disease and outcomes of aortic valve replacement for severe aortic stenosis

OBJECTIVES

The study sought to contrast risk profiles and compare outcomes of patients with severe aortic stenosis (AS) and coronary artery disease (CAD) who underwent aortic valve replacement (AVR) and coronary artery bypass grafting (AS+CABG) with those of patients with isolated AS who underwent AVR alone.

BACKGROUND

In patients with severe AS, CAD is often an incidental finding with underappreciated survival implications.

METHODS

From October 1991 to July 2010, 2,286 patients underwent AVR+CABG and 1,637 AVR alone. A propensity score was developed and used for matched comparisons of outcomes (1,082 patient pairs). Analyses of long-term mortality were performed for each group, then combined to identify common and unique risk factors.

RESULTS

Patients with AS+CAD versus isolated AS were older, more symptomatic, and more likely to be hypertensive, and had lower ejection fraction and greater arteriosclerotic burden but less severe AS. Hospital morbidity and long-term survival were poorer (43% vs. 59% at 10 years). Both groups shared many mortality risk factors; however, early risk among AS+CAD patients reflected effects of CAD; late risk reflected diastolic left ventricular dysfunction expressed as ventricular hypertrophy and left atrial enlargement. Patients with isolated AS and few comorbidities had the best outcome, those with CAD without myocardial damage had intermediate outcome equivalent to propensity-matched isolated AS patients, and those with CAD, myocardial damage, and advanced comorbidities had the worst outcome.

CONCLUSIONS

Cardiovascular risk factors and comorbidities must be considered in managing patients with severe AS. Patients with severe AS and CAD risk factors should undergo early diagnostics and AVR+CABG before ischemic myocardial damage occurs.

Relation of QRS shortening to cardiac output during temporary resynchronization therapy after cardiac surgery

Cardiac resynchronization therapy (CRT) can improve cardiac function in heart failure without increasing myocardial oxygen consumption. However, CRT optimization based on hemodynamics or echocardiography is difficult. QRS duration (QRSd) is a possible alternative optimization parameter. Accordingly, we assessed QRSd optimization of CRT during cardiac surgery. We hypothesized that QRSd shortening during changes in interventricular pacing delay (VVD) would increase cardiac output (CO). Seven patients undergoing coronary artery bypass, aortic or mitral valve surgery with left ventricular (LV) ejection fraction < or =40%, and QRSd > or =100 msec were studied. CRT was implemented at epicardial pacing sites in the left and right ventricle and right atrium during VVD variation after cardiopulmonary bypass. QRSd was correlated with CO from an electromagnetic aortic flow probe. Both positive and negative correlations were observed. Correlation coefficients ranged from 0.70 to -0.74 during VVD testing. Clear minima in QRSd were observed in four patients and were within 40 msec of maximum CO in two. We conclude that QRSd is not useful for routine optimization of VVD after cardiac surgery but may be useful in selected patients. Decreasing QRSd is associated with decreasing CO in some patients, suggesting that CRT can affect determinants of QRSd and ventricular function independently.

Characteristics of new cardiac surgery programs in the United States: mitigating the learning curve

BACKGROUND

New cardiac surgery programs continue to open across the United States, and it is not known how new programs deal with potentially low volumes during their start-up period. We compared patient, procedure, and physician characteristics and short-term mortality at established cardiac surgery programs, new programs in general hospitals, and new specialty cardiac hospitals.

METHODS

We used Medicare Provider Analysis and Review, part B physician claims, and denominator files to evaluate established and new programs performing coronary artery bypass graft surgery (CABG) from 1994-2003. Short-term mortality was defined as death in-hospital or within 30 days.

RESULTS

From 1994-2003, 257 new programs in general hospitals and 20 new specialty hospitals opened; and 884 established programs were in operation. New programs in general hospitals had much lower CABG volume than established programs and performed fewer concomitant valves and reoperations. New specialty hospitals had high CABG volume from inception, similar valve and reoperation rates to established programs, and conducted more elective procedures. Short-term mortality was significantly lower at new programs in general hospitals.

CONCLUSIONS

Start-up strategies used by new specialty hospitals and new programs in general hospitals differed markedly. By choosing to conduct safer procedures on low-risk patients, new general programs may have offset potential concerns about operating at low volume. Neither type of new program exhibited an increased risk of short-term mortality. The high volume at specialty hospitals may reassure patients and policy makers, although the high proportion of elective procedures and the new program's effect on surrounding hospitals require further consideration.

Relationship between the logistic EuroSCORE and the Society of Thoracic Surgeons Predicted Risk of Mortality score in patients implanted with the CoreValve ReValving system--a Bern-Rotterdam Study

BACKGROUND

Surgical risk scores, such as the logistic EuroSCORE (LES) and Society of Thoracic Surgeons Predicted Risk of Mortality (STS) score, are commonly used to identify high-risk or "inoperable" patients for transcatheter aortic valve implantation (TAVI). In Europe, the LES plays an important role in selecting patients for implantation with the Medtronic CoreValve System. What is less clear, however, is the role of the STS score of these patients and the relationship between the LES and STS.

OBJECTIVE

The purpose of this study is to examine the correlation between LES and STS scores and their performance characteristics in high-risk surgical patients implanted with the Medtronic CoreValve System.

METHODS

All consecutive patients (n = 168) in whom a CoreValve bioprosthesis was implanted between November 2005 and June 2009 at 2 centers (Bern University Hospital, Bern, Switzerland, and Erasmus Medical Center, Rotterdam, The Netherlands) were included for analysis. Patient demographics were recorded in a prospective database. Logistic EuroSCORE and STS scores were calculated on a prospective and retrospective basis, respectively.

RESULTS

Observed mortality was 11.1%. The mean LES was 3 times higher than the mean STS score (LES 20.2% +/- 13.9% vs STS 6.7% +/- 5.8%). Based on the various LES and STS cutoff values used in previous and ongoing TAVI trials, 53% of patients had an LES > or =15%, 16% had an STS > or =10%, and 40% had an LES > or =20% or STS > or =10%. Pearson correlation coefficient revealed a reasonable (moderate) linear relationship between the LES and STS scores, r = 0.58, P < .001. Although the STS score outperformed the LES, both models had suboptimal discriminatory power (c-statistic, 0.49 for LES and 0.69 for STS) and calibration.

CONCLUSIONS

Clinical judgment and the Heart Team concept should play a key role in selecting patients for TAVI, whereas currently available surgical risk score algorithms should be used to guide clinical decision making.

Statin therapy improves outcomes after valvular heart surgery

BACKGROUND

The beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG Co-A) reductase inhibitors (statins) in patients undergoing coronary artery bypass grafting have been recognized. Reduced mortality rates and clinical events have been demonstrated. These outcomes were examined in patients taking statins who underwent cardiac valve operations.

METHODS

This retrospective study included 447 consecutive patients undergoing valve operations between July 2004 and February 2006; 203 patients (45.6%) received statins preoperatively and postoperatively vs 244 who did not. Preoperative risk factors and outcome data for both cohorts were compared. Primary outcomes included 30-day mortality, renal failure, and postoperative stroke.

RESULTS

The statin group had more comorbidities. Although they had increased risk factors, including previous stroke (30 of 203 vs 16 of 244, p = 0.004), diabetes (66 of 203 vs 32 of 244, p < 0.0001), cerebrovascular disease (45 of 203 vs 24 of 244, p = 0.003), and dyslipidemia (191 of 203 vs 63 of 244, p < 0.0001), they had better outcomes. The unadjusted odds ratio (OR) for the composite end point of death/stroke/renal failure was 1.90 (95% confidence interval [CI], 0.95 to 3.76; p = 0.068) favoring the statin group. By univariate analysis, the adjusted OR for the composite end point demonstrated a benefit with statin therapy: diabetes, 2.29 (95% CI, 1.16 to 4.71; p = 0.024); stroke, 2.15 (95% CI, 1.06 to 4.35; p = 0.034); and renal dysfunction, 2.05 (95% CI, 1.02 to 4.13; p = 0.045).

CONCLUSIONS

Statin therapy in this population undergoing cardiac valve procedures was associated with decreased postoperative morbidity and death. The mechanism may be independent of statins' lipid-lowering effects. A prospective, randomized-control trial of statin therapy in this population is warranted.

Predictors of mortality after aortic valve replacement

Aortic valve replacement (AVR) is recommended as a standard surgical procedure for aortic valve disease. Still the evidence for commonly claimed predictors of post-AVR prognosis, in particular mortality, appears scant. This systematic review reports on the evidence for predictors of post-AVR mortality, and may be helpful in pre-surgical risk-stratification. In PubMed, we searched for original reports of post-AVR follow-up studies. We assessed the quality of study design and methods with a standardized checklist. Data of the reported predictors of mortality and outcomes were extracted. Twenty-eight studies met our inclusion criteria. Sixteen studies were considered of high quality. There is strong evidence that the risk of early mortality is increased by emergency surgery, while the risk of late mortality is increased with older age and preoperative atrial fibrillation. There is moderate evidence that the risk of early mortality is increased by older age, aortic insufficiency, coronary artery disease, longer cardiopulmonary bypass time, reduced left ventricular ejection fraction (LV-EF), infective endocarditis, hypertension, mechanical valves, preoperative pacing, dialysis-dependent renal failure and valve size; and that the risk for late mortality is increased by emergency surgery and urgency of the operation. There is little evidence for high New York Heart Association class, concomitant coronary artery bypass graft and many other commonly claimed risk factors for post-AVR mortality. The reported evidence on predictors of post-AVR mortality will help for pre-surgical risk-stratification, i.e. to discern patients at high or low risk for early and late post-AVR mortality. Future prognostic studies should take the evidence from this review into account and should focus on derivation of a predictive model for post-AVR survival.

Long-Term Consequences of Postoperative Heart Failure After Surgery for Aortic Stenosis Compared With Coronary Surgery

BACKGROUND

Although postoperative heart failure is a major determinant of operative mortality in cardiac surgery it has received little attention in the literature, and long-term consequences remain to be addressed. Therefore, the impact of postoperative heart failure on long-term survival in relation to other risk factors was studied.

METHODS

All patients undergoing aortic valve replacement (AVR) for aortic stenosis from 1995 through 2000 in the southeast region of Sweden (n = 398) were compared with a cohort, matched for age and sex, undergoing coronary artery bypass grafting (CABG [n = 398]). Risk factors for 5-year mortality were analyzed.

RESULTS

Forty-five AVR and 47 CABG patients required treatment for postoperative heart failure. Thirty-day, 1-year, and 5-year mortality in patients with and without postoperative heart failure after AVR were 6.7% versus 1.4% (p = 0.05), 8.9% versus 4.0% (p = 0.13), and 42.2% versus 14.2% (p < 0.0001) respectively. Corresponding results in the CABG group were 21.3% versus 1.1% (p < 0.0001), 25.5% versus 3.1% (p < 0.0001), and 36.2% versus 11.1% (p = 0.0015). Postoperative heart failure, preoperative renal dysfunction, procedure-associated stroke, body mass index less than 19 kg/m2, older age, preoperative atrial fibrillation, and preoperative anemia turned out as independent risk factors for 5-year mortality after AVR. In the CABG group, postoperative heart failure, diabetes mellitus, older age, and procedure-associated stroke emerged as independent risk factor for 5-year mortality.

CONCLUSIONS

Postoperative heart failure was associated with high early mortality after CABG whereas the grave consequences of postoperative heart failure after AVR for aortic stenosis became evident only with time.

Risk Index for Predicting In-Hospital Mortality for Cardiac Valve Surgery

BACKGROUND

Numerous studies have developed a "severity score" or "risk index" for short-term mortality associated with coronary artery bypass graft (CABG) surgery, but very few studies have developed risk indices derived from statistical models to predict outcomes for cardiac valve replacement patients.

METHODS

Data from New York's Cardiac Surgery Reporting System in 2001 to 2003 were used to develop statistical models that predict mortality for valve surgery and for valve/CABG surgery. These models were used to develop risk indices based on the type of valve surgery performed and several patient risk factors. The fit of each index was tested by examining the correspondence of expected and observed mortality rates for various risk score ranges using New York data between 1998 and 2000.

RESULTS

There were a total of 11 risk factors for valve patients without CABG surgery and 12 risk factors for patients with both valve and CABG surgery. Risk factors represented measures of demographics, type of valve surgery, previous open heart surgery, ventricular function, hemodynamic state, and various comorbidities. Possible variable scores ranged from 0 to 7 in the isolated valve model and 0 to 5 in the valve/CABG model. The highest overall risk scores possible for the two models were 49 for isolated valve surgery and 35 for valve/CABG surgery, and the highest scores observed for any patient were 32 and 26, respectively.

CONCLUSIONS

These valve surgery risk indices will enable providers to estimate patients' short-term mortality risk and allow for comparisons of valve surgery outcomes with other regions.

Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement

BACKGROUND

After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia-reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery.

STUDY DESIGN AND METHODS

This study was a randomized controlled trial. Forty patients scheduled for elective aortic valve replacement were randomly assigned to a control group (standard care) or an ANH group (target hematocrit level of 28%). All patients were managed with standard myocardial preservation techniques (cold blood cardioplegia, anesthetic preconditioning). The outcome measures included the release of myocardial enzymes, perioperative hemodynamic changes, the need for pharmacologic cardiovascular support, and cardiac complications.

RESULTS

In the ANH group, the postoperative release of troponin I (mean peak plasma concentrations, 1.7 ng/mL; 95% confidence interval, 1.4-2.1 ng/mL) and myocardial fraction of creatine kinase (22 U/L; range, 18-24 U/L) was significantly lower than in the control group (3.6 [range, 3.0-4.2] ng/mL and 45 [range, 39-51] U/L, respectively). In addition, requirement for inotropic support was significantly lower and fewer hemodiluted patients presented adverse cardiac events. After ANH, there was a significant decrease in heart rate (-11 +/- 6%) and rate-pressure product (-16 +/- 8%) until the aortic cross-clamping time and, at the end of surgery, the circulating levels of erythropoietin (EPO) were higher than in control patients (13.6 +/- 4.2 mUI/mL vs. 7.3 +/- 2.4 mUI/mL; p < 0.05).

CONCLUSIONS

Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.

Health‐Related Quality of Life Predicts Mortality in Older but Not Younger Patients Following Cardiac Surgery

The investigators assessed preoperative health-related quality of life as a predictor of 6-month mortality after cardiac surgery in older (65 years of age and older) vs. younger patients. Multivariable regression, stratified by age groups, was used to compare the association between preoperative Physical Component Summary and Mental Component Summary scores from the Short Form-36 health status survey and mortality. In multivariable analyses of older patients, lower preoperative Physical Component Summary (odds ratio, 1.54; 95% confidence interval, 1.19-2.00; p=0.01) and Mental Component Summary (odds ratio, 1.26; 95% confidence interval, 1.06-1.49; p=0.03) scores were independently associated with mortality. In contrast, neither Physical Component Summary (p=0.82) nor Mental Component Summary (p=0.79) scores were associated with mortality in the younger subgroup. This study demonstrated that preoperative health status is an independent predictor of mortality following cardiac surgery in older but not younger patients. Preoperative patient self-report of health status may be particularly useful in refining risk stratification and informing decision-making before and following cardiac surgery in older patients.

Time-varying risk factors for long-term mortality after coronary artery bypass graft surgery

BACKGROUND

There is a substantial literature on short-term mortality risk factors for coronary artery bypass graft (CABG) surgery. However, very few studies have examined risk factors for long-term mortality.

METHODS

We analyzed 56,543 veterans who underwent CABG surgery at one of 43 VA cardiac surgery centers between October 1, 1991, and March 30, 2001. Each patient was followed for a minimum of 3.5 months and a maximum of 9.5 years for mortality assessment. The time-varying effects of 22 mortality preoperative risk factors were evaluated using both standard Cox regression models and Cox B-spline regression models.

RESULTS

Six variables showed significant varying effects over time on mortality after surgery. The effects of previous heart surgery or preoperative intra-aortic balloon pump carried about 5 times and 3 times the risk, respectively, of dying on the first day after surgery, but were not significant during long-term follow-up. Conversely, diabetes had little additional risk immediately after surgery, but the risk increased steadily and doubled at 9.5 years after surgery. Three other risk variables--age, chronic obstructive pulmonary disease, and urgent or emergent status--also had risk changing by 50% to 60% over the next decade. Most of the other 16 risk variables were significantly associated with mortality, but the risk did not vary substantially over time.

CONCLUSIONS

Risk associated with some preoperative variables can change significantly during the decade after surgery, and risk assessments that assume constant risk during the postoperative period may substantially overestimate or underestimate risk at some times. These findings may help clinicians identify appropriate management strategies for patients during the years after CABG surgery, and support an emphasis on noncardiac comorbidities during later postoperative periods.

Validation and refinement of mortality risk models for heart valve surgery

BACKGROUND

The Northern New England Cardiovascular Disease Study Group (NNE) recently published risk models for hospital mortality after heart valve surgery. The Providence Health System Cardiovascular Study Group (PHS) has been collecting similar heart valve data for 8 years, providing an ideal opportunity to both validate the NNE risk models and attempt to produce an improved model, by using some different modeling techniques.

METHODS

From 1997 to 2004, 3,324 patients aged 30 to 95 years underwent aortic valve replacement (AVR), and 1,596 underwent mitral valve replacement or repair (MVRR) at one of nine PHS medical centers. We used area under the receiver operating characteristic curve (c-index) to measure model discrimination, and Hosmer-Lemeshow statistic (H-L) to measure calibration. We modified the NNE models by ungrouping continuous variables, seeking optimal transformations of continuous variables, and imputing missing values by multiple regression.

RESULTS

The prevalence and the lethality of risk factors were similar in PHS and NNE patients. The NNE models fit PHS patients well: c-index (95% confidence interval) = 0.75 (0.70 to 0.80) for AVR and 0.81 (0.76 to 0.86) for MVRR; H-L = 3.95 (p = 0.861) for AVR and 7.10 (p = 0.526) for MVRR. A single PHS model performed slightly better for both positions: c-index = 0.79 (0.75 to 0.83) for AVR and 0.84 (0.80 to 0.88) for MVRR; H-L = 2.75 (p = 0.949) for AVR and 12.21 (p = 0.142) for MVRR.

CONCLUSIONS

The NNE models for aortic and mitral valve surgery were successfully validated using PHS patients. Using some different statistical approaches to modeling, we produced a new, unified model for both positions.

The Association Between Duration of Storage of Transfused Red Blood Cells and Morbidity and Mortality After Reoperative Cardiac Surgery: Retracted

Red blood cells (RBCs) undergo numerous changes during storage; however, the clinical relevance of these storage "lesions" is unclear. We hypothesized that the duration of storage of transfused RBCs is associated with mortality after repeat sternotomy for cardiac surgery, because these patients are at high risk for both RBC transfusion and adverse outcome. We retrospectively analyzed 434 patients who underwent repeat median sternotomy for coronary artery bypass graft or valve surgery and who received allogeneic RBCs. Three-hundred-twenty-one (74%) patients met the criteria for eligibility. After adjusting for the effects of confounders and the total number of RBC transfusions, the duration of storage of the oldest RBC unit transfused was found to be associated with both in-hospital mortality (Cox proportional hazard ratio (HR) = 1.151; P < 0.0001) and out-of-hospital mortality (HR = 1.116; P < 0.0001). The mean duration of storage of transfused RBCs was also an independent predictor of in-hospital mortality (HR = 1.036; P < 0.0001). Independent associations between the duration of storage of transfused RBCs and acute renal dysfunction and intensive care unit and hospital length of stay were also observed. The duration of storage of RBCs is associated with adverse outcome after repeat sternotomy for cardiac surgery. The clinical significance of this finding should be investigated in a large, randomized, blinded clinical trial.

Determinants of operative mortality in valvular heart surgery

OBJECTIVE

In some respects, outcome reporting in valvular surgery has been hampered by focusing on specific populations, reluctance to publish high-risk subgroups, and possibly skewed or inadequate samples. The goal of this study was to evaluate risk factors for operative mortality comprehensively across the entire spectrum of cardiac valvular procedures over the past decade.

METHODS

All 409,904 valve procedures in the Society of Thoracic Surgeons database performed between 1994 and 2003 were assessed, and Society of Thoracic Surgeons preoperative and operative variables were related to operative mortality by using a multivariable logistic regression model. Data were greater than 95% complete, and the relative importance of relevant risk factors was determined by ranking odds ratios. The analysis had a high predictive power, with a C statistic of 0.735.

RESULTS

In the model, 19 variables independently influenced operative mortality (all P < .01). The most significant was nonelective (acute) presentation (odds ratios, 2.11), followed by advanced age (odds ratios, 1.88), reoperation (odds ratios, 1.61), endocarditis (odds ratios, 1.59), and coronary disease (odds ratios, 1.58). Generally, valve replacement was associated with higher mortality than repair (odds ratios, 1.52). Overall, female gender was very important (odds ratios, 1.37), and earlier year of operation increased risk (odds ratios, 1.34), implying improving outcomes over time. Although any single comorbidity, on average, was only moderately contributory (odds ratios, 1.19), specific comorbidities, such as renal failure, or multiple comorbidities in a given patient could be very significant. Aortic root reconstruction carried the highest risk (odds ratios, 2.78), followed by tricuspid valve surgery (odds ratios, 2.26), multiple valve procedures (odds ratios, 2.06), and then isolated mitral (odds ratios, 1.47), pulmonic (odds ratios, 1.29), and aortic (reference procedure) operations. Reduced ejection fraction and severity of valve lesion were relatively less important (odds ratios, 1.34 and 0.83, respectively).

CONCLUSIONS

These data illustrate the significance of acute presentation in determining operative risk, and earlier surgical intervention under elective conditions might be emphasized for all types of significant valve lesions. Because aortic root reconstruction doubles mortality compared with simple aortic valve procedures, root replacement should be reserved for specific root pathology. Finally, issues related to reoperation, endocarditis, valve repair, gender, and the various procedures deserve more detailed examination.

Preoperative statin treatment is associated with reduced postoperative mortality and morbidity in patients undergoing cardiac surgery: An 8-year retrospective cohort study

BACKGROUND

Cardiac surgical procedures can be associated with significant morbidity and mortality. Recently, it has been recognized that statins might induce multiple biologic effects independent of lipid lowering that could potentially ameliorate adverse surgical outcomes. Accordingly, this study tested the central hypothesis that pretreatment with statins before cardiac surgery would reduce adverse postoperative surgical outcomes.

METHODS

Demographic and outcomes data were collected retrospectively for 3829 patients admitted for planned cardiac surgery between February 1994 and December 2002. Statin pretreatment occurred in 1044 patients who were comparable with non-statin-pretreated (n = 2785) patients with regard to sex, race, and age. Primary outcomes examined included postoperative mortality (30-day) and a composite morbidity variable.

RESULTS

The odds of experiencing 30-day mortality and morbidity were significantly less in the statin-pretreated group, with unadjusted odds ratios of 0.43 (95% confidence interval [CI], 0.28-0.66) and 0.72 (95% CI, 0.61-0.86), respectively. Risk-adjusted odds ratios for mortality and morbidity were 0.55 (95% CI, 0.32-0.93) and 0.76 (95% CI, 0.62-0.94), respectively, by using a logistic regression model and 0.51 (95% CI, 0.27-0.94) and 0.71 (95% CI, 0.55-0.92), respectively, in the propensity-matched model, demonstrating significant reductions in 30-day morbidity and mortality. In a subsample of patients undergoing valve-only surgery (n = 716), fewer valve-only patients treated with statins experienced mortality, although these results were not statistically significant (1.96% vs 7.5%).

CONCLUSIONS

These findings indicate that statin pretreatment before cardiac surgery confers a protective effect with respect to postoperative outcomes.

EuroSCORE Predicts Long-Term Mortality After Heart Valve Surgery

BACKGROUND

The European System for Cardiac Operative Risk Evaluation (EuroSCORE) is the most rigorously evaluated scoring system in cardiac surgery. We sought to evaluate the performance of EuroSCORE in the prediction of long-term mortality in patients undergoing heart valve surgery.

METHODS

Medical records of patients with isolated or combined heart valve surgery, who were discharged alive (n = 1035), were retrospectively reviewed. Their operative surgical risks were calculated according to EuroSCORE model (standard and logistic). Long-term survival data (mean follow-up 4.5 +/- 3.1 years) were obtained from the National Death Index. Kaplan-Meier curves of the quartiles of standard and logistic EuroSCORE were plotted.

RESULTS

The estimated 5-year survival rates of the quartiles in the standard and logistic EuroSCORE model were: 90.0% +/- 2.3%, 85.1% +/- 2.3%, 64.8% +/- 3.3%, and 55.1% +/- 3.7% (p < 0.0001, log-rank test with adjustment for trend) and 90.4% +/- 2.2%, 86.4% +/- 2.5%, 66.9% +/- 3.3%, and 56.1% +/- 3.3% (p < 0.0001, log-rank test with adjustment for trend) respectively. The odds of death in the highest-risk quartile were 7.46- and 7.82-fold higher than the odds of death in the lowest-risk quartile for standard and logistic EuroSCORE respectively.

CONCLUSIONS

EuroSCORE can be used to predict not only in-hospital mortality, for which it was originally designed, but also long-term mortality in the whole context of heart valve surgery. This outcome can be predicted using the standard EuroSCORE, which is very simple and easy in its calculation.