Original article
Cardiovascular
Risk Index for Predicting In-Hospital Mortality for Cardiac Valve Surgery

https://doi.org/10.1016/j.athoracsur.2006.09.051Get rights and content

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.

Section snippets

Data

The data used for the study were taken from New York’s Cardiac Surgery Reporting System, which was created in late 1988 for the purpose of improving the quality of cardiac care in the state as well as to inform hospitals, surgeons and the public of patient outcomes and risk factors. Data in the system include patient demographics (age, sex, race, and so forth), numerous patient risk factors and comorbidities, patient disposition, complications of care, and hospital and surgeon identifiers (see

Results

A total of 10,702 patients in the study underwent isolated valve surgery, with an overall in-hospital mortality rate of 4.41%. Another 8,823 patients underwent concomitant valve and CABG surgery, with an in-hospital mortality rate of 8.89%. Table 1 contains the significant independent risk factors for mortality for the first group along with their logistic regression coefficients, odds ratios with 95% confidence intervals, and p values; and Table 2 presents the same information for the

Comment

This study presents risk indices for two types of cardiac surgery patients: those undergoing isolated valve surgery and those undergoing valve surgery along with CABG surgery. As with our two recent studies of risk indices for isolated CABG surgery and percutaneous coronary interventions [1, 24], the database used in this study is large and population-based, and is audited for completeness and accuracy. Results of the study show that the risk index based on New York 2001 to 2003 valve data

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    Copyright © 2007 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.