TAVR enters a new risk-scoring era

“There has been need for a risk calculator specific to TAVR since the patient population has only some overlap with the patients who underwent SAVR in the past,” said Dr. John D. Carroll, professor and director of interventional cardiology at the University of Colorado at Denver, Aurora, and a member of the TVT Registry panel that developed the calculator. “The STS score does not include variables that are frequently found in TAVR patients, such as liver disease, pulmonary hypertension, very-advance age, and frailty.”

^{University of Colorado Hospital}

Dr. John D. Carroll

A big plus for the new TVT risk calculator is its derivation from thousands of real-world, U.S. patients, Dr. Carroll noted. “It provides a patient-specific risk assessment rather than an assessment based on average patients from TAVR clinical trials.” Dr. Carroll added that since its introduction he has used the TVT risk calculator for some of his own patients being considered for TAVR.

The Saint Luke’s TAVR risk calculator

Although experts foresee an important role for profiling a patient’s predicted gain or loss in quality of life following TAVR as another element in the discussions between heart teams and patients, the risk calculator becoming available in May from Health Outcomes Sciences faces some significant issues, they said.

The Saint Luke’s Mid America team that developed the calculator used as their endpoint for a poor patient outcome 6 months after TAVR the combined rate of either death or two different measures of impaired quality of life: a Kansas City Cardiomyopathy Questionnaire–Overall Summary Scale (KCCQ-OS) score of less than 45 (measured on a scale of 0-100, where higher scores reflect better quality of life and function) or at least a 10-point reduction from baseline in a patient’s KCCQ-OS score.

By predicting a patient’s likelihood of emerging from TAVR with either a low or significantly worsened quality of life and function, this score is a “complement” to the TVT in-hospital mortality score, said Dr. Suzanne V. Arnold, a cardiologist at Saint Luke’s Mid America and one of the lead developers of this risk calculator.

^{Mitchel L. Zoler/Frontline Medical News}

Dr. Suzanne V. Arnold

“In-hospital mortality is an assessment of whether a patient will make it through the TAVR procedure. Our model is more about failure to recover after the procedure,” she explained in an interview. She and others also say that the Saint Luke’s calculator is a measure of probable futility when performing TAVR – that is, the likelihood that a patient will either not live long after the procedure or gain enough benefit from it to make performing the TAVR procedure an attractive option.

Dr. Arnold and her associates derived and validated the risk model using data collected from the “high risk” patients enrolled in the initial PARTNER trial and registry, so for the time being it remains primarily applicable to high-risk patients, who have classically been defined as patients with a STS risk score of 8% or greater (patients who have at least an 8% predicted risk of death during the 30 days following SAVR). She and her associates plan to see if they can validate the Saint Luke’s calculator in intermediate risk patients with aortic stenosis (usually defined as patients with a STS risk score of 4%-8%) with data collected in trials that enrolled these patients, such as PARTNER 2. At the ACC’s annual meeting in April in Chicago, Dr. Arnold presented a report in which she and her associates further validated their model using data collected from the high-risk patients enrolled in the CoreValve TAVR trial. This validation confirmed that the model worked “beautifully,” Dr. Arnold said.

The Saint Luke’s risk calculator uses six data entries: whether or not the patient has diabetes, atrial fibrillation, or requires oxygen support at home; whether the patient has no, mild, or moderate-to-severe dementia; the patient’s mean aortic gradient; and the patient’s score on the Kansas City Cardiomyopathy Questionnaire-12 (an abbreviated version of the 23-question KCCQ-OS scale). The result it produces – the likelihood of death or poor quality of life at 6 months – is “another piece of data to help the physician, surgeon, and patient make a decision” on whether to proceed with TAVR, she explained. “I would probably advise that if the predicted risk is high, the patient consider undergoing balloon aortic valvuloplasty” instead of TAVR “to see whether the patient has some recovery before committing to TAVR, but there are no hard and fast rules,” she acknowledged.

Dr. Arnold gave this recent case she had as an example of how running the Saint Luke’s risk calculator helped decision making: