Quantifying MR: The Stroke Volume Method

Key Takeaways

• Stroke volume method uses mitral inflow vs LVOT outflow volumes
• No need for PISA geometry; relies on Doppler measurements
• Mitral annular diameter is the missing measurement for complete MR assessment
• Method validates or replaces PISA when color Doppler is suboptimal
• Regurgitant volume = Mitral SV minus LVOT SV; RF and EROA follow

Pulse Analysis

The 2017 ASE guidelines emphasize an integrative approach to mitral regurgitation (MR) quantification, and the stroke volume method fits neatly into that framework. Unlike the proximal isovelocity surface area (PISA) technique, which demands precise aliasing and geometric assumptions, the stroke volume method simply subtracts the LVOT stroke volume—derived from pulsed‑wave Doppler and LVOT diameter—from the mitral inflow stroke volume. Because these Doppler measurements are part of every standard transthoracic echo, clinicians can compute regurgitant volume (RVol), regurgitant fraction (RF) and effective regurgitant orifice area (EROA) without additional imaging time.

Practically, the method shines when color Doppler quality is compromised by eccentric jets, poor acoustic windows, or high heart rates. By providing an independent metric, it helps resolve discrepancies that often arise between PISA‑derived EROA and clinical severity. Moreover, the calculation is straightforward: RVol = Mitral SV − LVOT SV; RF = (RVol ÷ Mitral SV) × 100%; EROA = RVol ÷ MR VTI. Adding the mitral annular diameter—readily measured in the parasternal long‑axis view—completes the dataset, enabling a full quantitative MR profile.

Adopting the stroke volume method can streamline workflow, reduce inter‑observer variability, and align practice with contemporary guideline recommendations. For cardiac imaging labs, it means leveraging existing data to deliver more accurate MR grading, which directly influences therapeutic decisions such as timing of surgical repair or transcatheter intervention. As the field moves toward data‑driven, reproducible assessments, the stroke volume method stands out as a pragmatic, evidence‑based tool for everyday clinical use.