An update on predictive biomarkers for major adverse cardiovascular events in patients undergoing vascular surgery

Complex relationship between low albumin level and poor outcome after lower extremity procedures for peripheral artery disease

OBJECTIVE

A low albumin level has been associated with poor outcome, including death, in surgical patients. The mechanistic relationship, however, is more complex than simply nutritional. As studies are scant in the vascular population, we sought to examine the association of low albumin level with outcomes in patients undergoing open and endovascular lower extremity procedures for peripheral artery disease.

METHODS

Patients with peripheral artery disease undergoing lower extremity procedures (2008-2015) were selected from Cerner Health Facts database (Cerner Corporation, Kansas City, Mo) using International Classification of Diseases, Ninth Revision diagnosis and procedure codes. Age, sex, disease severity, and other comorbidities were captured. Outcomes were identified using codes and encounter data. A χ²analysis and multivariable logistic regression were performed.

RESULTS

There were 6170 patients evaluated; 4562 (74%) underwent endovascular procedures and 1608 (26%) underwent open surgery. Low albumin level (<3.5 g/dL) was associated with age ≥80 years (23.1% vs 16.3% normal; P < .0001), black race (21% vs 11.6% normal; P < .0001), tissue loss (38% vs 16.4% normal; P < .0001), and higher Charlson index (mean, 3.1 vs 2.2 in the normal group; P < .0001). Low albumin level was also associated with longer length of stay (4.9 vs 2.2 days normal; P < .0001), higher in-hospital mortality (1.9% vs 0.3% normal; P < .0001), and higher 30-day readmission (15% vs 12.7% normal; P = .02). Multivariable analysis demonstrated that low albumin level was strongly associated with in-hospital death (odds ratio [OR], 5.23; 95% confidence interval [CI], 2.00-13.70), infection (OR, 2.51; 95% CI, 1.96-3.22), renal failure (OR, 2.61; 95% CI, 1.79-3.79), and cardiac complications (OR, 2.59; 95% CI, 1.69-3.96). After multivariable adjustment, there was no association between albumin level and 30-day readmission.

CONCLUSIONS

Low preoperative albumin levels are associated with in-hospital death, prolonged length of stay, and severe morbidity after open and endovascular lower extremity procedures. As the majority of lower extremity procedures are elective, serious consideration should be given to deferring elective procedures until albumin levels have been optimized. Because of the pleiotropic effects of albumin, including antiplatelet and inflammatory function, study of this complex relationship may offer insights into how best to integrate this novel biomarker into vascular surgery decision-making.

Major Cardiac Events in Patients Admitted to Intensive Care After Vascular Noncardiac Surgery: A Retrospective Cohort

Introduction. Patients proposed to vascular noncardiac surgery (VS) have several comorbidities associated with major adverse cardiac events (MACE). We evaluated incidence, predictors, and outcomes, and compared different scores to predict MACE after VS. Methods. We included all patients admitted from 2006 to 2013. Perioperative MACE included cardiac arrhythmias, myocardial infarction (MI), cardiogenic pulmonary edema (CPE), acute heart failure (AHF), and cardiac arrest (CA). Lee Revised Cardiac Risk Index (RCRI), Vascular Quality Initiative (VQI-CRI), Vascular Study Group of New England (VSG-CRI), and South African Vascular Surgical (SAVS-CRI) Cardiac Risk Indexes were calculated and analyzed. We performed multivariate logistic regression to assess independent predictors with calculation of odds ratio (OR) and 95% confidence interval (CI). To reduce overfitting, we used leave-one-out cross-validation approach. The Predictive ability of scores was tested using area under receiver operating characteristic curve (AUROC). Results. A total of 928 patients were included. We observed 81 MACE (28 MI, 22 arrhythmias, 10 CPE, 9 AHF, 12 CA) in 60 patients (6.5%): 3.3% in intermediate-risk surgery and 9.8% in high-risk surgery. Previous history of coronary artery disease (OR = 3.2, CI = 1.8-5.7), atrial fibrillation (OR = 5.1, CI = 2.4-11.0), insulin-treated diabetes mellitus (OR = 3.26, CI = 1.51-7.06), mechanical ventilation (OR = 2.75, CI = 1.41-4.63), and heart rate (OR = 1.02, CI = 1.01-1.03) at admission were considered independent risk factors in multivariate analysis. The AUROC of our model was 0.79, compared with RCRI (0.66), VSG-CRI (0.69), VQI-CRI (0.71), and SAVS-CRI (0.73). Conclusions. Observed MACE were within predicted range (1% to 5% after intermediate-risk surgery and >5% after high-risk surgery). SAVS-CRI and VQI-CRI had slightly better predictive capacity than VSG-CRI or RCRI.