Christina Mora Mangano

Adverse Cerebral Outcomes after Coronary Bypass Surgery

Background Acute changes in cerebral function after elective coronary bypass surgery are a difficult clinical problem. We carried out a multicenter study to determine the incidence and predictors of — and the use of resources associated with — perioperative adverse neurologic events, including cerebral injury. Methods In a prospective study, we evaluated 2108 patients from 24 U.S. institutions for two general categories of neurologic outcome: type I (focal injury, or stupor or coma at discharge) and type II (deterioration in intellectual function, memory deficit, or seizures). Results Adverse cerebral outcomes occurred in 129 patients (6.1 percent). A total of 3.1 percent had type I neurologic outcomes (8 died of cerebral injury, 55 had nonfatal strokes, 2 had transient ischemic attacks, and 1 had stupor), and 3.0 percent had type II outcomes (55 had deterioration of intellectual function and 8 had seizures). Patients with adverse cerebral outcomes had higher in-hospital mortality (21 percent of patients ...

Cerebral Injury After Cardiac Surgery Identification of a Group at Extraordinary Risk

BACKGROUND AND PURPOSE Cerebral injury after cardiac surgery is now recognized as a serious and costly healthcare problem mandating immediate attention. To effect solution, those subgroups of patients at greatest risk must be identified, thereby allowing efficient implementation of new clinical strategies. No such subgroup has been identified; however, patients undergoing intracardiac surgery are thought to be at high risk, but comprehensive data regarding specific risk, impact on cost, and discharge disposition are not available. METHODS We prospectively studied 273 patients enrolled from 24 diverse US medical centers, who were undergoing intracardiac and coronary artery surgery. Patient data were collected using standardized methods and included clinical, historical, specialized testing, neurological outcome and autopsy data, and measures of resource utilization. Adverse outcomes were defined a priori and determined after database closure by a blinded independent panel. Stepwise logistic regression models were developed to estimate the relative risks associated with clinical history and intraoperative and postoperative events. RESULTS Adverse cerebral outcomes occurred in 16% of patients (43/273), being nearly equally divided between type I outcomes (8.4%; 5 cerebral deaths, 16 nonfatal strokes, and 2 new TIAs) and type II outcomes (7.3%; 17 new intellectual deterioration persisting at hospital discharge and 3 newly diagnosed seizures). Associated resource utilization was significantly increased--prolonging median intensive care unit stay from 3 days (no adverse cerebral outcome) to 8 days (type I; P<0.001) and from 3 to 6 days (type II; P<0.001), and increasing hospitalization by 50% (type II, P=0.04) to 100% (type I, P<0.001). Furthermore, specialized care after hospital discharge was frequently necessary in those with type I outcomes, in that only 31% returned home compared with 85% of patients without cerebral complications (P<0.001). Significant risk factors for type I outcomes related primarily to embolic phenomena, including proximal aortic atherosclerosis, intracardiac thrombus, and intermittent clamping of the aorta during surgery. For type II outcomes, risk factors again included proximal aortic atherosclerosis, as well as a preoperative history of endocarditis, alcohol abuse, perioperative dysrhythmia or poorly controlled hypertension, and the development of a low-output state after cardiopulmonary bypass. CONCLUSIONS These prospective multicenter findings demonstrate that patients undergoing intracardiac surgery combined with coronary revascularization are at formidable risk, in that 1 in 6 will develop cerebral complications that are frequently costly and devastating. Thus, new strategies for perioperative management--including technical and pharmacological interventions--are now mandated for this subgroup of cardiac surgery patients.

Trends in Acute Kidney Injury, Associated Use of Dialysis, and Mortality After Cardiac Surgery, 1999 to 2008

BACKGROUND The development of acute kidney injury (AKI) after cardiac surgery is associated with significant mortality, morbidity, and cost. The last decade has seen major changes in the complexity of cardiac surgical candidates and in the number and type of cardiac surgical procedures being performed. METHODS Using data from the Nationwide Inpatient Sample, we determined the annual rates of AKI, AKI requiring dialysis (AKI-D), and inpatient mortality after cardiac surgery in the United States in the years 1999 through 2008. RESULTS Inpatient mortality with AKI and AKI-D decreased from 27.9% and 45.9%, respectively, in 1999 to 12.8% and 35.3%, respectively, in 2008. Compared with 1999, the odds of AKI and AKI-D in 2008, adjusted for demographic and clinical factors, were 3.30 (95% confidence interval [CI]: 2.89 to 3.77) and 2.23 (95% CI: 1.78 to 2.80), respectively. Corresponding adjusted odds of death associated with AKI and AKI-D were 0.31 (95% CI: 0.26 to 0.36) and 0.47 (95% CI: 0.34 to 0.65.) Taken together, the attributable risks for death after cardiac surgery associated with AKI and AKI-D increased from 30% and 5%, respectively, in 1999 to 47% and 14%, respectively, in 2008. CONCLUSIONS In sum, despite improvements in individual patient outcomes over the decade 1999 to 2008, the population contribution of AKI and AKI-D to inpatient mortality after surgery increased over the same period.

Multicenter Study of Target-Controlled Infusion of Propofol-Sufentanil or Sufentanil-Midazolam for Coronary Artery Bypass Graft Surgery

Background The use of target-controlled infusions of anesthetics for coronary artery bypass graft surgery has not been studied in detail. The effects of target-controlled infusions of propofol or sufentanil, supplemented by infusions of sufentanil or midazolam, respectively, were evaluated and compared. Methods At 14 clinical sites, 329 patients were given a target-controlled infusion of propofol (n = 165) to produce effect-site concentration (Ce) of greater or equal to 3-micro gram/ml or a target-controlled infusion of sufentanil (n = 164). Sufentanil or midazolam, respectively, also were infused. Systolic hypertension, hypotension, tachycardia, and bradycardia were assessed by measuring heart rate and blood pressure every minute during operation. Myocardial ischemia was assessed perioperatively by monitoring ST segment deviation via continuous three-lead Holter electrocardiography, and it was evaluated during operation by monitoring left ventricular wall motion abnormality via transesophageal echocardiography. Results The measured cardiovascular parameters were satisfactory and usually similar for the patients receiving propofol-sufentanil or sufentanil-midazolam. The primary endpoint of the percentage of patients with intraoperative ST segment deviation (23 plus/minus 6% vs. 24 plus/minus 6%, P = 0.86) did not differ significantly between the two groups. The incidence of left ventricular wall motion abnormality shown on transesophageal echocardiography before (19 plus/minus 4% vs. 26 plus/minus 4%, P = 0.25) and after (23 plus/minus 4% vs. 31 plus/minus 5%, P = 0.32) cardiopulmonary bypass also did not differ significantly for the two groups. Changes in intraoperative target concentration were more frequent with propofol-sufentanil anesthetic than with sufentanil-midazolam (11.7 plus/minus 7.1 vs. 7.3 plus/minus 3.6, P <0.001). The incidence of intraoperative hypotension (77% vs. 55%, P <0.001), the use of inotropic/vasopressor medications (93% vs. 84%, P = 0.01), and the administration of crystalloids (2.8 plus/minus 1.4 L vs. 2.4 plus/minus 1.2 L, P < 0.001) were significantly greater in the propofol-sufentanil group. Conversely, the incidence of intraoperative hypertension (43% vs. 54%, P = 0.05) and the use of antihypertensive/vasodilator medications (70% vs. 90%, P < 0.001) were significantly less in the propofol-sufentanil group. Conclusions Target-controlled infusions of propofol or sufentanil, supplemented by infusions of sufentanil or midazolam, respectively, were suitable to provide anesthesia for coronary artery bypass graft surgery. Continuous monitoring revealed a high prevalence of hemodynamic abnormalities. Despite greater hypotension in the propofol-sufentanil group and greater hypertension in the sufentanil-midazolam group, episodes of myocardial ischemia were similar for both groups and were not temporally related to episodes of hemodynamic abnormalities.

Is it gender, methodology, or something else?

See related articles on pages 929, 936, 950, and 959. Are Outcomes Different? The thesis that women are different from men is not argued in any more important venue than the surgical theatre. The questions of whether and why women have higher probabilities of poor outcomes after coronary artery bypass grafting (CABG) have been repeatedly asked. A common denominator among published investigations is that the preoperative profile of the female patient is vastly different from that of the male patient. Some risk factors traditionally associated with increased morbidity and mortality after CABG are more commonly represented in the preoperative profile of the female patient. The extent to which these factors explain gender differences, however, varies among studies. Some investigations report higher adjusted mortality for women, whereas others, with application of adjustment strategies, report similar in-hospital mortality between women and men, and yet others report similar postoperative mortality for women and men despite differences in baseline characteristics. How can multiple studies examining the role of gender in surgical outcomes lead to such varied conclusions despite similar analyses of observational databases? If one structures the question correctly, collects the necessary data, and performs the appropriate analysis, one should expect a consistent answer. On the subject of gender, is the question structured to be answered, is there some unmeasured or unknown biologic variable or process-of-care decision in the perioperative period that is influencing outcomes, or is it the variable application of statistical methodology?

Case 3--1999. Severe fetal bradycardia in a pregnant woman undergoing hypothermic cardiopulmonary bypass.

The extracorporeal circuit was primed with 1,000 mL of whole blood and 500 mL of lactated Ringers solution. After the initiation of bypass, perfusion pressure was maintained at 70 mmHg, blood flow at 3.8 L/min, and hematocrit at 29%. Systemic hypothermia (mixed-venous blood temperature equal to 28°C) and aortic cross-clamping were associated with an acute decrease in FHR to 50 beats/min. This fetal bradycardia did not improve despite an increase in blood flow to 4.6 L/rain (2.94 L/min/m 2) and perfusion pressure to 75 to 80 mmHg. Finally, the administration of atropine, 0.4 mg, did not cause an increase in FHR. Throughout extracorporeal circulation, maternal perfusion pressure was maintained at 70 mmHg, blood flow at 4.5 L/rain, and maternal systemic temperature at 28°C. Alpha-stat acidbase management showed maternal arterial blood gas values of PaO2, 378 mmHg; PaCO2, 41 mmHg; pH, 7.39; and base excess, -3. FHR during hypothermia stabilized at a rate of 50 beats/rain with the loss of beat-to-beat variability. After 50 minutes of hypothermic cardiopulmonary bypass (CPB), rewarming was initiated. When the mixed-venous temperature increased to 33°C, FHR increased to 120 beats/rain. At 35°C, FHR increased to 130 to 140 beats/rain with a return of normal beat-to-beat variability. After the discontinuation of bypass support, hemodynamics improved (cardiac output, 8.4 L/min) and FHR was 130 beats/rain. During the uncomplicated postoperative period, no uterine contractions were observed and FHR remained within normal range. The patient returned to the hospital at 37 weeks of gestation and delivered a healthy baby boy. DISCUSSIONt

Perioperative Stroke, Encephalopathy, and Central Nervous System Dysfunction

The leading cause of mortality in adult populations throughout the world is atherosclerosis, which results in cardiovascular and cerebrovascular complications and consumes substantive health care resources. The impact of atherosclerosis on patients undergoing surgery is also considerable, given the multiple stresses occurring during, and especially following, the surgical procedures, thereby precipitating vascular morbidity. Perioperative cerebrovascular morbidity and mortality occur in approximately 10% of the 600,000 patients who undergo cardiac surgery annually, consuming approximately

Case 5—1995 marked mixed venous hemoglobin desaturation in a patient during hypothermic cardiopulmonary bypass

13 billion, which is expended on in-hospital, intensive care unit (ICU), and long-term specialized care for these neurological complications of stroke, encephalopathy, and cognitive dysfunction. Furthermore, risk of these outcomes will continue to increase as the surgical population ages. Principal among the etiologies of focal stroke and encephalopathy appear to be perioperative hypotension and precipitation of macroemboli and microemboli. As a result, new detection techniques for these events have been instituted, including (1) continuous hemodynamic monitoring, for detection of hypotensive episodes; (2) transesophageal echocardiography, for detection of aortic atherosclerosis, a potential source for emboli; and (3) transcranial Doppler sonography, for detection of cerebral emboli, as well as determination of cerebral blood flow. Recent large-scale multicenter studies have identified risk factors and indices for perioperative central nervous system (CNS) morbidity. Regarding therapy, a number of pharmacological approaches are currently under consideration; principal among these approaches are agents that can modulate the excitotoxic response, including glutamate receptor antagonists (NMDA, AMPA, metabotrophic), calcium channel blockers, free radical scavengers, and agents that modify the inflammatory white cell response. Although a number of laboratory, animal, and smaller clinical trials have been conducted, only one large-scale multicenter program to date has been conducted to assess the efficacy of adenosine modulation. These data, collected in more than 4,000 patients undergoing cardiac surgery, suggest that in addition to mitigation of myocardial injury, stroke also may be modulated by enhancing adenosine concentration in the area of cerebral ischemia. However, these preliminary findings must be validated in appropriately powered clinical trials. Finally, postoperative stroke and encephalopathy consume substantive resources, resulting in prolonged length-of-stay (17 days in-hospital 10 days for patients suffering Q-wavc infarction, vs 7 days for patients having no adverse outcome) and prolonged length-of-stay in the ICU following surgery (5 vs 3 vs 2 days, respectively). Hospital costs increase by approximately 3- to 4-fold in patients who suffer CNS outcomes following surgery. In conclusion, perioperative CNS morbidity and mortality is a critical problem that affects a substantial portion of the surgical population and consumes considerable health care resources. Over the next several years, attention must be focused on this important problem, and clinical and research resources should be redirected toward the solution of perioperative CNS morbidity.

Quality of Life After Coronary Artery Bypass Surgery: Past Progress and Future Directions

perfusion flow rate and gas flow up to 8.5 L/min each, as well as increasing the FIO2 to 100%, did not improve the SvO2. Subsequent to the decrease of SvO2, generalized shivering was observed, and was suspected as the cause of this complication. A supplementary dose of pancuronium, 0.2 mg/kg, was administered, the shwering dissipated, and the SVO2, PaO2, and PaCO2 returned to the control values (Table 1). The whole-body oxygen consumption (VO2) was computed as the product of arterial-venous oxygen content difference multiplied by the perfusion flow: VO 2 (mL/min) = {[(SAO2% - SVO2%) x Hb x 1 36] + [(PaO2 - PvO2) x 0.003]} x perfusion flow x 10 where SaOz(%) = arterial oxygen saturation, SVO2(%) = mixed venous oxygen saturation, Hb = Hemoglobin concentration (g/dL), 1.36 = Hufner factor (mL/g), PaO2 = arterial oxygen tension (mmHg) measured at 37°C, PvO2 = mixed venous oxygen tension (mmHg) measured at 37°C, and 0.003 = solubility coefficient of oxygen at 37°C (mL/dL/ mmHg).

Renal Dysfunction after Myocardial Revascularization: Risk Factors, Adverse Outcomes, and Hospital Resource Utilization

Historically, morbidity and mortality have been the primary outcome measures in coronary artery bypass research. Limited health care resources have led to greater emphasis on cost as a primary outcome mea sure. These are each important measures, but they fail to directly assess what patients care about, which is their overall quality of life (QOL). When QOL is used as an outcome in medical research, it should encompass at a minimum the following domains: physical status, mental function, social interaction, and disease-specific measure. Fortunately, QOL assessment instruments already exist that are reliable, valid, and sensitive to change. This article describes how QOL is defined, what instruments are available, how they have been devel oped, and how they are selected. Next, QOL in the coronary artery bypass literature is reviewed. This in cludes both the large randomized trials as well as studies focusing solely on QOL. Finally, future directions for QOL as an outcome measure are examined.