Prognostic implications of invasive hemodynamics during cardiac resynchronization therapy: Stroke work outperforms dP/dt.

Background: Invasive measurements of left ventricular (LV) hemodynamic performance can evaluate acute response to cardiac resynchronization therapy (CRT).

Objective: The study sought to determine which metric, maximum rate of LV pressure rise (LV dP/dt) or LV stroke work (LVSW), is more strongly associated with long-term prognosis.

Methods: CRT patients were prospectively included from 3 academic centers. Invasive pressure-volume loop measurements during implantation were performed, and LV dP/dt and LVSW were determined at baseline and during biventricular pacing (BVP) as well as their relative increase (%Δ). Hazard ratios (HRs) for the primary outcome of 8-year all-cause mortality were derived using Cox proportional hazards. The secondary endpoint was echocardiographic response, defined as 6-month LV end-systolic volume reduction ≥15%.

Results: Paired data from 82 patients were analyzed (67% male; age 66 ± 9 years; QRS duration 158 ± 22 ms, median survival time 72 months). Survival was better when LVSW during BVP was ≥4400 mL∙mm Hg (HR 0.21, 95% CI 0.08-0.58, < .003) or when ΔLVSW% was ≥10% (HR 0.22, 95% CI 0.08-0.65,  = .006). In multivariate analysis, following direct comparison of continuous measures of acute ΔLV dP/dt% and ΔLVSW%, only ΔLVSW% remained associated with the primary endpoint (HR 0.982 per percentage point, = .028). In contrast to LV dP/dt (all > .05), significant associations with echocardiographic response were found for stroke work during BVP (area under the receiver-operating characteristic curve 0.745, = .001) and ΔLVSW% (area under the receiver-operating characteristic curve 0.803, < .001).

Conclusion: Stroke work, but not LV dP/dt is consistently associated with long-term prognosis and response after CRT. Our results therefore favor the use of stroke work as the hemodynamic parameter to predict long-term outcome after CRT.