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Observed to expected 30-day mortality as a benchmark for transcatheter aortic valve replacement
Matthew C Henn1, Alan Zajarias2, Nishath Quader2
1Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, Mo.
The Journal of Thoracic and Cardiovascular Surgery
|November 21, 2018
Summary
The Society for Thoracic Surgery Predicted Risk of Mortality (STS-PROM) overestimates 30-day mortality after transcatheter aortic valve replacement (TAVR). Achieving an observed-to-expected (O:E) ratio below 0.6 is a realistic goal for TAVR programs.
Area of Science:
- Cardiology
- Interventional Cardiology
- Health Services Research
Background:
- The observed-to-expected (O:E) mortality ratio is a key metric for evaluating transcatheter aortic valve replacement (TAVR) trials.
- Early TAVR trials reported O:E ratios below 0.6 using the Society for Thoracic Surgery Predicted Risk of Mortality (STS-PROM).
- Recent Transcatheter Valve Therapy (TVT) Registry data show O:E ratios around 1.0, creating a discrepancy.
Purpose of the Study:
- To investigate the discordance in O:E ratios for TAVR.
- To evaluate institutional O:E ratios for 30-day mortality after TAVR.
- To compare institutional TAVR outcomes with STS-PROM predictions.
Main Methods:
- Prospective data collection for 546 TAVR patients from 2008-2015, with retrospective review.
- Calculation of observed mortality and STS-PROM to determine O:E ratios.
- Comparison of O:E ratios across various subgroups, including risk strata and procedural approaches.
Main Results:
- The overall 30-day mortality O:E ratio was 0.4, significantly less than 1.
- O:E ratios remained below 0.5 across low, moderate, and high STS-PROM risk groups.
- Transapical TAVR showed a higher O:E ratio (0.8) than transfemoral TAVR (0.2).
- O:E ratios for commercial (0.5) and research (0.3) TAVR patients were similar and significantly less than 1.
Conclusions:
- STS-PROM consistently overestimates 30-day mortality following TAVR.
- An O:E ratio below 0.6 is achievable and may represent a realistic benchmark for TAVR programs.
- Current TVT Registry results may not be representative of optimal commercial TAVR performance; programs exceeding an O:E ratio of 0.6 should reassess their processes.
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