Classifying cardiac changes pre-TAVR may boost risk stratification

A four-stage system that quantifies the extent of cardiac changes associated with aortic stenosis was linked to the odds of death and readmission following transcatheter aortic valve replacement (TAVR), a finding that may aid cardiologists in making prognoses and engaging in shared decision-making with patients.

Lead author Miho Fukui, MD, and colleagues at University of Pittsburgh Medical Center sought to evaluate the utility of the staging classification system in 689 patients with severe aortic stenosis who underwent TAVR at their institution from July 2011 through January 2017.

The staging criteria were first proposed in an analysis of the PARTNER 2 trials published in the European Heart Journal in 2017. In that study, patients experienced a stepwise increase in mortality as the stages progressed, but outcomes were only evaluated out to one year.

Fukui et al. sought to confirm the reproducibility of those findings in a different patient cohort while also testing whether the association remained during a longer follow-up period (median of 20.1 months) and extended beyond mortality to readmission rates.

Using transthoracic echocardiography images taken pre-TAVR, the researchers divided patients into four stages based on their markers of abnormal cardiac function:

  • Stage 1: Increased left ventricular mass index; early mitral inflow to early diastolic mitral annulus velocity (E/e′) greater than 14; and left ventricular ejection fraction below 50 percent. Thirteen percent of patients in the study fell in this category.
  • Stage 2: Left atrial volume index greater than 34 mL/m2; moderate to severe mitral regurgitation; and atrial fibrillation (62 percent of patients in the study).
  • Stage 3: Pulmonary artery systolic pressure of at least 60 mm Hg; and moderate to severe tricuspid regurgitation (21 percent of patients in the study).
  • Stage 4: Moderate to severe right ventricular dysfunction (4 percent of patients in the study).

Compared to stage 1 patients, those in stage 2 were 37 percent more likely to die during follow-up, a difference which wasn’t statistically significant. However, those in stages 3 and 4 were 2.24 times and 2.83 times more likely to die, respectively, while individuals in stage 3 were also 84 percent more likely to hospitalized for a cardiac cause.

“Our findings confirm and support the findings by Généreux et al. (from the PARTNER trial) demonstrating that the extent of cardiac changes in the proposed aortic stenosis staging system has a graded association with all-cause mortality during a long-term, 2-year, post-TAVR follow-up of patients,” Fukui and co-authors wrote in JAMA Cardiology. “In addition, to our knowledge, we report for the first time that the proposed staging classification system is also associated with post-TAVR readmissions for both cardiac and noncardiac causes, particularly for patients with advanced pulmonary hypertension and moderate to severe tricuspid regurgitation.”

The authors noted this increase in readmissions was statistically significant even after adjustment for risk factors and comorbidities included in the Society of Thoracic Surgeons’ Predicted Risk of Mortality score, “making a compelling case for the inclusion of this staging system in future TAVR risk stratification models and shared decision making.”

The authors said some patients in the early part of their study received first-generation TAVR devices as opposed to newer products, which may have impacted outcomes. They acknowledged the study was further limited by its single-center, retrospective design, and said additional studies are needed before this process is more broadly adopted.

“Whether this proposed staging classification system, bearing its simplifications and limitations, could serve as a framework for monitoring disease progression and making early referral to interventions for patients who start to demonstrate extravalvular cardiac dysfunction will require further study and a larger prospective evaluation,” they wrote.