Yinghui Miao

Risk Index for Perioperative Renal Dysfunction/Failure Critical Dependence on Pulse Pressure Hypertension

Background— An acute renal event after coronary bypass graft surgery is associated with high mortality and substantial additive cost. Methods and Results— This prospective and descriptive study of 4801 patients having coronary bypass graft surgery with cardiopulmonary bypass from November 1996 to June 2000 at 70 centers in 16 countries established associations between predictor variables and postoperative renal composite (renal dysfunction and/or renal failure) from a cohort of 2381 patients and developed a risk index assessed in a validation cohort of 2420 patients. Postoperative renal composite occurred in 231 patients (4.8%). Independent and significant risk factors were age >75 years (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.23 to 3.37; P=0.006), preoperative congestive heart failure (OR, 2.38; CI, 1.55 to 3.64; P<0.001), prior myocardial infarction (OR, 1.75; CI, 1.08 to 2.83; P=0.023), preexisting renal disease (OR, 3.71; CI, 2.41 to 5.70; P<0.001), intraoperative multiple inotrope use (OR, 2.75; CI, 1.75 to 4.31; P<0.001), intraoperative intra-aortic balloon pump insertion (OR, 4.41; CI, 2.21 to 8.80; P<0.001), cardiopulmonary bypass >2 hours (OR, 1.78; CI, 1.15 to 2.74; P=0.01), and preoperative pulse pressure such that for every additional 20–mm Hg increment in pulse pressure >40 mm Hg, there was an OR of 1.49 (CI, 1.17 to 1.89; P=0.001). Patients with pulse pressure hypertension >80 mm Hg were 3 times more likely to die a renal-related death compared with those without (3.7% versus 1.1%). Conclusions— Beside established risk factors, pulse pressure is independently and significantly associated with increased renal composite.

Lack of Effectiveness of the Pulmonary Artery Catheter in Cardiac Surgery

BACKGROUND: The pulmonary artery catheter (PAC) continues to be used for monitoring of hemodynamics in patients undergoing coronary artery bypass graft (CABG) surgery despite concerns raised in other settings regarding both effectiveness and safety. Given the relative paucity of data regarding its use in CABG patients, and given entrenched practice patterns, we assessed the impact of PAC use on fatal and nonfatal CABG outcomes as practiced at a diverse set of medical centers. METHODS: Using a formal prospective observational study design, 5065 CABG patients from 70 centers were enrolled between November 1996 and June 2000 using a systemic sampling protocol. Propensity score matched-pair analysis was used to adjust for differences in likelihood of PAC insertion. The predefined composite endpoint was the occurrence of any of the following: death (any cause), cardiac dysfunction (myocardial infarction or congestive heart failure), cerebral dysfunction (stroke or encephalopathy), renal dysfunction (dysfunction or failure), or pulmonary dysfunction (acute respiratory distress syndrome). Secondary variables included treatment indices (inotrope use, fluid administration), duration of postoperative intubation, and intensive care unit length of stay. After categorization based on PAC and transesophageal echocardiography use (both, neither, PAC only, transesophageal echocardiography only), we performed the primary analysis contrasting PAC only and neither (total, 3321 patients), from which propensity paring yielded 1273 matched pairs. RESULTS: The primary endpoint occurred in 271 PAC patients versus 196 without PAC (21.3% vs.15.4%; adjusted odds ratio [AOR], 1.68; 95% confidence interval [CI], 1.24 to 2.26; P < 0.001). The PAC group had an increased risk of all-cause mortality, 3.5% vs 1.7% (AOR, 2.08; 95% CI, 1.11 to 3.88; P = 0.02) and an increased risk of cardiac (AOR, 1.58; 95% CI, 1.14 to 2.20; P = 0.007), cerebral (AOR, 2.02; 95% CI, 1.08 to 3.77; P = 0.03) and renal (AOR, 2.47; 95% CI, 1.68 to 3.62; P < 0.001) morbid outcomes. PAC patients received inotropic drugs more frequently (57.8% vs 50.0%; P < 0.001), had a larger positive IV fluid balance after surgery (3220 mL vs 3022 mL; P = 0.003), and experienced longer time to tracheal extubation (15.40 hours [11.28/20.80] versus 13.18 hours [9.58/19.33], median plus Q1/Q3 interquartile range; P < 0.0001). Use of PAC was also associated with prolonged intensive care unit stay (14.5% vs 10.1%; AOR, 1.55; 95% CI, 1.06 to 2.27; P = 0.02). CONCLUSIONS: Use of a PAC during CABG surgery was associated with increased mortality and a higher risk of severe end-organ complications in this propensity-matched observational study. A randomized controlled trial with defined hemodynamic goals would be ideal to either confirm or refute our findings.

Patterns of Use of Perioperative Angiotensin-Converting Enzyme Inhibitors in Coronary Artery Bypass Graft Surgery With Cardiopulmonary Bypass Effects on In-Hospital Morbidity and Mortality

Background— Despite proven benefit in ambulatory patients with ischemic heart disease, the pattern of use of angiotensin-converting enzyme inhibitors (ACEIs) in coronary artery bypass graft surgery has been erratic and controversial. Methods and Results— This is a prospective observational study of 4224 patients undergoing coronary artery bypass graft surgery. The cohort included 1838 patients receiving ACEI therapy before surgery and 2386 (56.5%) without ACEI exposure. Postoperatively, the pattern of ACEI use yielded 4 groups: continuation, 915 (21.7%); withdrawal, 923 (21.8%); addition, 343 (8.1%); and no ACEI, 2043 (48.4%). Continuous treatment with ACEI versus no ACEI was associated with substantive reductions of risk of nonfatal events (adjusted odds ratio for the composite outcome, 0.69; 95% confidence interval, 0.52–0.91; P=0.009) and a cardiovascular event (odds ratio, 0.64; 95% confidence interval, 0.46–0.88; P=0.006). Addition of ACEI de novo postoperatively compared with no ACEI therapy was also associated with a significant reduction of risk of composite outcome (odds ratio, 0.56; 95% confidence interval, 0.38–0.84; P=0.004) and a cardiovascular event (odds ratio, 0.63; 95% confidence interval, 0.40–0.97; P=0.04). On the other hand, continuous treatment of ACEI versus withdrawal of ACEI was associated with decreased risk of the composite outcome (odds ratio, 0.50; 95% confidence interval, 0.38–0.66; P<0.001), as well as a decrease in cardiac and renal events (P<0.001 and P=0.005, respectively). No differences in in-hospital mortality and cerebral events were noted. Conclusions— Our study suggests that withdrawal of ACEI treatment after coronary artery bypass graft surgery is associated with nonfatal in-hospital ischemic events. Furthermore, continuation of ACEI or de novo ACEI therapy early after cardiac surgery is associated with improved in-hospital outcomes.

Pulse Pressure and Risk of Adverse Outcome in Coronary Bypass Surgery

BACKGROUND: Among ambulatory patients, an increase in pulse pressure (PP) is a well-established determinant of vascular risk. The relationship of PP and acute perioperative vascular outcome among patients having coronary artery bypass graft (CABG) surgery is less well known. METHODS: We conducted a prospective observational study involving 5436 patients having elective CABG surgery requiring cardiopulmonary bypass. Of these, 4801 met final inclusion criteria. Comprehensive data were captured for medical history, intraoperative and postoperative physiologic and laboratory measures, diagnostic testing, and clinical events. The relationship between preoperative hypertension (systolic, diastolic, PP) and ischemic cardiac and cerebral outcomes and death was assessed using multivariable logistic regression; P < 0.05 was considered significant. RESULTS: Nine hundred and seventeen patients (19.1%) had fatal and nonfatal vascular complications, including 146 patients (3.0%) with cerebral and 715 patients (14.9%) with cardiac events. In-hospital mortality occurred in 147 patients (3.1%). Among all blood pressure variables measured preoperatively, PP was most strongly associated with an increased risk of postoperative complications. PP increments of 10 mm Hg (above a threshold of 40 mm Hg) were associated with an increased risk of cerebral events (adjusted odds ratio: 1.12; 95% CI [1.002–1.28]; P = 0.026). The incidence of a cerebral event and/or death from neurologic complications nearly doubled for patients with PP >80 mm Hg versus ≤80 mm Hg (5.5% vs 2.8%; P = 0.004). PP more than 80 mm Hg was also found to be associated with cardiac complications, increasing the incidence of congestive heart failure by 52%, and death from cardiac cause by nearly 100% (P = 0.003 and 0.006, respectively). CONCLUSION: An increase in PP was independently and significantly associated with greater fatal and nonfatal adverse cerebral and cardiac outcomes in patients having CABG surgery. These findings highlight the associated risks of preoperative PP on acute postoperative vascular outcomes.

Patterns of Use of Perioperative ACE Inhibitors in CABG Surgery with Cardiopulmonary Bypass: Effects on In-Hospital Morbidity and Mortality

Background— Despite proven benefit in ambulatory patients with ischemic heart disease, the pattern of use of angiotensin-converting enzyme inhibitors (ACEIs) in coronary artery bypass graft surgery has been erratic and controversial. Methods and Results— This is a prospective observational study of 4224 patients undergoing coronary artery bypass graft surgery. The cohort included 1838 patients receiving ACEI therapy before surgery and 2386 (56.5%) without ACEI exposure. Postoperatively, the pattern of ACEI use yielded 4 groups: continuation, 915 (21.7%); withdrawal, 923 (21.8%); addition, 343 (8.1%); and no ACEI, 2043 (48.4%). Continuous treatment with ACEI versus no ACEI was associated with substantive reductions of risk of nonfatal events (adjusted odds ratio for the composite outcome, 0.69; 95% confidence interval, 0.52–0.91; P=0.009) and a cardiovascular event (odds ratio, 0.64; 95% confidence interval, 0.46–0.88; P=0.006). Addition of ACEI de novo postoperatively compared with no ACEI therapy was also associated with a significant reduction of risk of composite outcome (odds ratio, 0.56; 95% confidence interval, 0.38–0.84; P=0.004) and a cardiovascular event (odds ratio, 0.63; 95% confidence interval, 0.40–0.97; P=0.04). On the other hand, continuous treatment of ACEI versus withdrawal of ACEI was associated with decreased risk of the composite outcome (odds ratio, 0.50; 95% confidence interval, 0.38–0.66; P<0.001), as well as a decrease in cardiac and renal events (P<0.001 and P=0.005, respectively). No differences in in-hospital mortality and cerebral events were noted. Conclusions— Our study suggests that withdrawal of ACEI treatment after coronary artery bypass graft surgery is associated with nonfatal in-hospital ischemic events. Furthermore, continuation of ACEI or de novo ACEI therapy early after cardiac surgery is associated with improved in-hospital outcomes.

A multinational study of the influence of health-related quality of life on in-hospital outcome after coronary artery bypass graft surgery

BACKGROUND The effect of health-related quality of life on in-hospital outcomes after coronary artery bypass grafting surgery has not been investigated in international multicenter studies. We hypothesized that poor preoperative health status is associated with mortality and length of hospital stay. METHODS In the Multicenter Study of Perioperative Ischemia Epidemiology II, preoperative Short-Form 12, Mental Component Summary (MCS), and Physical Component Summary (PCS) scores were obtained prospectively from 4,811 patients (3,834 men, 977 women) undergoing coronary artery bypass grafting surgery at 72 centers in 17 countries. Primary outcome measures were in-hospital mortality and prolonged (>14 days) length of hospital stay. RESULTS One hundred fifty-one patients (3.1%) died. After adjustment for regional differences, a 10-point reduction in MCS score was associated with higher mortality risk (odds ratio [OR] 1.17, 95% CI 1.004-1.37, P = .04) and prolonged hospital stay (OR 1.11, 95% CI 1.01-1.21, P = .03). The preoperative PCS score was not associated with mortality risk but significantly predicted prolonged length of hospital stay (OR 1.20, 95% CI 1.09-1.33, P < .001). There was no significant interaction between gender and either the MCS or the PCS score. DISCUSSION The preoperative PCS predicted prolonged postoperative hospital stay, whereas the preoperative MCS score was an independent predictor of both prolonged length of hospital stay and mortality. Preoperative assessment of health-related quality of life factors with the Short-Form 12 might be a useful tool for risk stratification and planning for hospital discharge and rehabilitation.

Response to Letter Regarding Article, “Risk Index for Perioperative Renal Dysfunction/Failure: Critical Dependence on Pulse Pressure Hypertension”

BACKGROUND An acute renal event after coronary bypass graft surgery is associated with high mortality and substantial additive cost. METHODS AND RESULTS This prospective and descriptive study of 4801 patients having coronary bypass graft surgery with cardiopulmonary bypass from November 1996 to June 2000 at 70 centers in 16 countries established associations between predictor variables and postoperative renal composite (renal dysfunction and/or renal failure) from a cohort of 2381 patients and developed a risk index assessed in a validation cohort of 2420 patients. Postoperative renal composite occurred in 231 patients (4.8%). Independent and significant risk factors were age >75 years (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.23 to 3.37; P=0.006), preoperative congestive heart failure (OR, 2.38; CI, 1.55 to 3.64; P<0.001), prior myocardial infarction (OR, 1.75; CI, 1.08 to 2.83; P=0.023), preexisting renal disease (OR, 3.71; CI, 2.41 to 5.70; P<0.001), intraoperative multiple inotrope use (OR, 2.75; CI, 1.75 to 4.31; P<0.001), intraoperative intra-aortic balloon pump insertion (OR, 4.41; CI, 2.21 to 8.80; P<0.001), cardiopulmonary bypass >2 hours (OR, 1.78; CI, 1.15 to 2.74; P=0.01), and preoperative pulse pressure such that for every additional 20-mm Hg increment in pulse pressure >40 mm Hg, there was an OR of 1.49 (CI, 1.17 to 1.89; P=0.001). Patients with pulse pressure hypertension >80 mm Hg were 3 times more likely to die a renal-related death compared with those without (3.7% versus 1.1%). CONCLUSIONS Beside established risk factors, pulse pressure is independently and significantly associated with increased renal composite.