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Registry model may be valid predictor of TAVR in-hospital mortality
A predictive model of in-hospital mortality after transcatheter aortic valve replacement demonstrates favorable discrimination and calibration indices, according to recent findings.
The model was developed using data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (TVT) Registry.
In the study, Fred H. Edwards, MD, of the department of surgery, University of Florida College of Medicine–Jacksonville, and colleagues extracted patient data on consecutive patients undergoing TAVR at 265 participating TVT Registry sites between November 2011 and February 2014 to serve as the development sample.
The researchers selected potential covariates from the TVT Registry data collection form and used logistic regression to estimate the association between discharge mortality and baseline covariates.
Records from the development patient sample were used to identify a final set of nine predictors. The model was tested for discrimination and calibration in a validation sample of consecutive TAVR procedures performed between March 1 and Oct. 8, 2014, at 314 participating registry sites.
The development sample consisted of 13,672 patients (mean age, 82.1 years; 48.9% men). The validation cohort comprised 6,868 patients (mean age, 81 years; 51.7% men).
The researchers found that in-hospital mortality occurred 5.3% of the time. Analysis of discrimination revealed a C-statistic of 0.67 (95% CI, 0.65-0.69) in the development group and 0.66 (95% CI, 0.62-0.69) in the validation group.
The final covariates for the model were age (OR =1.13; 95% CI, 1.06-1.2), glomerular filtration rate per 5-U increments (OR = 0.93; 95% CI, 0.91-0.95), hemodialysis (OR = 3.25; 95% CI, 2.42-4.37), NYHA functional class IV (OR = 1.25; 95% CI, 1.03-1.52), severe chronic lung disease (OR = 1.67; 95% CI, 1.35-2.05), nonfemoral access site (OR = 1.96; 95% CI, 1.65-2.33) and categories 2 (OR = 1.57; 95% CI, 1.2-2.05), 3 (OR = 2.7; 95% CI, 2.05-3.55) and 4 (OR = 3.34; 95% CI, 1.59-7.02) of procedural acuity, also known as operative priority, an assessment of procedure urgency based on a patient’s condition.
Laura Mauri
In the validation sample, no significant differences were seen in the slope and intercept of the model calibration line and an ideal line representing perfect calibration. Good agreement was revealed between predicted vs. observed in-hospital mortality rates.
Small but important step
In a related editorial, Laura Mauri, MD, MSc, and Patrick T. O’Gara, MD, of the cardiovascular division, department of medicine, Brigham and Women’s Hospital and Harvard Medical School, wrote that “the TVT [Registry] offers a rich data set from which to characterize TAVR patients treated in practice, whose attributes may differ from those included in randomized clinical trials.”
Patrick T. O’Gara
They concluded that “a reliable risk score might in the future provide sites a method to compare their patients and outcomes more accurately to provide the local heart care team a tool for continuous quality improvement. While the currently reported risk score can be improved, Edwards and colleagues have marked yet another small yet important step on the pathway to making better decisions with our patients.” – by Jennifer Byrne
Disclosure: Edwards and O’Gara report no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures. Mauri reports receiving institutional research grants from Abbott, Boston Scientific and Medtronic.