Risk factors for morbidity and mortality after colectomy for colon cancer.

PURPOSE: Comorbid conditions affect the risk of adverse outcomes after surgery, but the magnitude of risk has not previously been quantified using multivariate statistical methods and prospectively collected data. Identifying factors that predict results of surgical procedures would be valuable in assessing the quality of surgical care. This study was performed to define risk factors that predict adverse events after colectomy for cancer in Department of Veterans Affairs Medical Centers. METHODS: The National Veterans Affairs Surgical Quality Improvement Program contains prospectively collected and extensively validated data on more than 415,000 surgical operations. All patients undergoing colectomy for colon cancer from 1991 to 1995 who were registered in the National Veterans Affairs Surgical Quality Improvement Program database were selected for study. Independent variables examined included 68 preoperative and 12 intraoperative clinical risk factors; dependent variables were 21 specific adverse outcomes. Stepwise logistic regression analysis was used to construct models predicting the 30-day mortality rate and 30-day morbidity rates for each of the ten most frequent complications. RESULTS: A total of 5,853 patients were identified; 4,711 (80 percent) underwent resection and primary anastomosis. One or more complications were observed in 1,639 of 5,853 (28 percent) patients. Prolonged ileus (439/5,853; 7.5 percent), pneumonia (364/5,853; 6.2 percent), failure to wean from the ventilator (334/5,853; 5.7 percent), and urinary tract infection (292/5,853; 5 percent) were the most frequent complications. The 30-day mortality rate was 5.7 percent (335/5,853). For most complications, 30-day in-hospital mortality rates were significantly higher for patients with a complication than for those without. Thirty-day mortality rates exceeded 50 percent if postoperative coma, cardiac arrest, a pre-existing vascular graft prosthesis that failed after colectomy, renal failure, pulmonary embolism, or progressive renal insufficiency occurred. Preoperative factors that predicted a high risk of 30-day mortality included ascites, serum sodium >145 mg/dl, "do not resuscitate" status before surgery, American Society of Anesthesiologists classes III and IV OR V, and low serum albumin. CONCLUSIONS: Mortality rates after colectomy in Veterans Affairs hospitals are comparable with those reported in other large studies. Ascites, hypernatremia, do not resuscitate status before surgery, and American Society of Anesthesiologists classes III and IV OR V were strongly predictive of perioperative death. Clinical trials to decrease the complication rate after colectomy for colon cancer should focus on these risk factors.

Prognostic models of thirty-day mortality and morbidity after major pulmonary resection.

BACKGROUND: A part of the prospective, multi-institutional National Veterans Affairs Surgical Quality Improvement Program was developed to predict 30-day mortality and morbidity for patients undergoing a major pulmonary resection. METHODS: Perioperative data were acquired from 194,319 noncardiac surgical operations at 123 Veterans Affairs Medical Centers between October 1, 1991, and August 31, 1995. Current Procedural Terminology code-based analysis was undertaken for major pulmonary resections (lobectomy and pneumonectomy). Preoperative, intraoperative, and outcome variables were collected. The 30-day mortality and morbidity models were developed by means of multivariable stepwise logistic regression with the preoperative and intraoperative variables used as independent predictors of outcome. RESULTS: A total of 3516 patients (mean age 64 9 years) underwent either lobectomy (n = 2949) or pneumonectomy (n = 567). Thirty-day mortality was 4.0% for lobectomy (119/2949) and 11.5% for pneumonectomy (65/567). The preoperative predictors of 30-day mortality were albumin, do not resuscitate status, transfusion of more than 4 units, age, disseminated cancer, impaired sensorium, prothrombin time more than 12 seconds, type of operation, and dyspnea. When the intraoperative variables were considered, intraoperative blood loss was added to the preoperative model. In the presence of these intraoperative variables in the model, do not resuscitate status and prothrombin time more than 12 seconds were only marginally significant. Thirty-day morbidity, defined as the presence of 1 or more of the 21 predefined complications, was 23.8% for lobectomy (703/2949) and 25.7% for pneumonectomy (146/567). In multivariable models, independent preoperative predictors (P <.05) of 30-day morbidity were age, weight loss greater than 10% in the 6 months before surgery, history of chronic obstructive pulmonary disease, transfusion of more than 4 units, albumin, hemiplegia, smoking, and dyspnea. When intraoperative variables were added to the preoperative model, the duration of operation time and intraoperative transfusions were included in the model and albumin became marginally significant. CONCLUSIONS: This analysis identifies independent patient risk factors that are associated with 30-day mortality and morbidity for patients undergoing a major pulmonary resection. This series provides an initial risk-adjustment model for major pulmonary resections. Future refinements will allow comparative assessment of surgical outcomes and quality of care at many institutions.

Determinants of survival and left ventricular performance after mitral valve replacement. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease.

To determine how survival and clinical status were related to left ventricular (LV) size and systolic function after mitral valve replacement, 104 patients (48 mitral regurgitation [MR], 33 mitral stenosis [MS], and 23 MS/MR) with isolated mitral valve replacement were evaluated before and after surgery. Preoperative hemodynamic abnormalities by cardiac catheterization were improved 6 months after surgery in all three patient groups. The patients with MR exhibited reductions in LV end-diastolic volume index (EDVI) (117 +/- 51 to 89 +/- 27 ml/m2, p less than 0.001) and ejection fraction (EF) (0.56 +/- 0.15 to 0.45 +/- 0.13, p less than 0.001); however, the ratio of forward stroke volume to end-diastolic volume increased (0.32 +/- 0.21 to 0.45 +/- 0.17, p less than 0.001) because of the elimination of regurgitant volume. Survival analysis revealed that mortality was significantly higher in MS or MS/MR patients with postoperative EDVI more than 101 ml/m2 (p less than 0.001 and p less than 0.042, respectively) and in MR patients with postoperative EF less than or equal to 0.50 (p less than 0.031). Also, the majority of patients with MR or MS/MR and postoperative EDVI more than 101 ml/m2 and EF less than or equal to 0.50 were in New York Heart Association class III or IV. Multivariate logistic regression analysis in the patients with MR revealed that the strongest predictor of postoperative EF was preoperative EF (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)