A new hemodynamic measurement can provide prognostic information that goes beyond just the degree of aortic regurgitation after percutaneous aortic implantation, according to a single-center, retrospective, European study.

The study validates the team’s earlier findings in a slightly larger group of patients. Called aortic regurgitation index (AR index), the parameter is measured by subtracting the left ventricular end-diastolic pressure from the diastolic blood pressure and dividing the result by systolic blood pressure, and then multiplying it by 100.

The measurement can provide additional information beyond echocardiography when it comes to assessing the severity and outcome of periprosthetic aortic regurgitation (periAR), wrote Dr. Mariuca Vasa-Nicotera and colleagues. Even patients with nonexistent or mild periAR after transcatheter aortic valve implantation (TAVI) can be stratified based on their AR index score. It can also help predict 1-year mortality after TAVI.

The findings "are not going to change practice," commented Dr. William Zoghbi, chief of cardiovascular imaging at Methodist DeBakey Heart and Vascular Center in Houston, who was not involved in the study. Rather, the AR index "would help with predicting prognosis for those individuals who have valve implantation."

AR index is also more than just an index of valve regurgitation, said Dr. Zoghbi, who is also the current president of the American College of Cardiology. The measurement shows whether the heart has a significant abnormality in diastolic function and how it is handing the hemodynamic load of valvular regurgitation, he said.

Paravalvular leakage is a common observation following TAVI, and growing evidence has shown an association between the leakage and dramatic increase in morbidity and mortality.

The researchers analyzed data from 122 high-risk or inoperable patients who underwent TAVI during January 2007–March 2011 at Glenfield University Hospital in Leicester, United Kingdom.

The procedure was performed using third^-generation 18-F Medtronic CoreValves or Edwards SAPIEN valves. Afterward, severity of periAR was assessed angiographically, echocardiographically by transesophageal echocardiography, and hemodynamically.

Patients were then divided into two groups on the basis of periAR: 102 had no or mild periAR (26 and 76 patients, respectively), and 20 had moderate or severe periAR (18 and 2 patients).

There were significant differences between the two patient groups.

Patients with moderate to severe periAR after TAVI had a significantly higher EuroSCORE (28.5, compared with 21.2 in those with no to mild periAR) and Society of Thoracic Surgeons mortality score (9.5 and 6.8, respectively). They also had a higher rate of myocardial infarction (40% v. 10%), and a lower left ventricular ejection fraction (45 v. 51).

Thirty-two patients (26%) died during the 1-year follow-up.

Among those remaining, 1-year mortality was 60% in patients with moderate to severe periAR, compared with 20% in patients with no or mild periAR.

The AR index declined in step with periAR severity, from 29.4 in patients with no periAR to 28.0 in those with mild periAR, to19.6 in patients with moderate periAR, and to 7.6 with severe periAR.

One-year mortality by AR index also paralleled that by periAR. That outcome was tripled in patients with an AR index of less than 25, compared with patients who had an AR index of at least 25 (42.3% vs. 14.3%), the authors reported.

AR index was also useful in patients with no or mild periAR, and provided complementary prognostic information, according to the authors.

The patients in that group who had an AR index of at least 25 had a 1-year mortality rate of 14.3%. But that rate was more than doubled those with an AR index of less than 25, at 31.3%. (All patients with moderate to severe periAR after TAVI had an AR index of less than 25.)

Dr. Vasa-Nicotera, who led the study, also published a similar study earlier this year, involving 146 patients with the CoreValve prosthesis.

In that study, the group concluded, "The assessment of the AR index allows a precise judgment of periAR, independently predicts 1-year mortality after TAVI, and provides prognostic information that is complementary to the degree of periAR."

In their current paper, the authors wrote that since "The validity of the AR index could be confirmed in this independent cohort of another high-volume TAVI center," the finding can be generalized.

They added that a prospective multicenter trial might be needed to verify the results. It is also not clear if valves other than Medtronic CoreValve and Edwards SAPIEN will yield the same results.

Dr. Zoghbi added that AR index can also be measure noninvasively with Doppler echocardiography, something that can be considered in the future.

Dr. Vasa-Nicotera had no relevent disclosures. Other investigators disclosed ties to CoreValve/Medtronic and Edwards-Sapien, the makers of the valves used in the study. Dr. Zoghbi had no relevant disclosures.

Aortic Regurgitation Index Can Improve TAVR Prognosis