Radial arterial versus left ventricular dP/dt for assessment of contractility in patients undergoing transcatheter aortic valve replacement: a retrospective observational study.

backgroundLeft ventricular (LV) contractility is a core characterization of cardiac function that provides therapeutic guidance in both chronic and acute patient care. Measurement of the change in pressure over time in the left ventricle (LV dP/dt) is a clinical gold standard for evaluating cardiac contractility but is invasive and has associated risks. Measurement of dP/dt from a radial arterial pressure catheter offers a less invasive and safer alternative. Studies comparing these two measurements are limited and have conflicting conclusions. The objective of this study was to evaluate the correlations between LV and radial arterial dP/dt and clarify the clinical utility of radial dP/dt.

methodsThis was a retrospective observational study carried out at a large tertiary academic medical center. Data was collected from the electronic medical records of patients who underwent transcatheter aortic valve replacement (TAVR) with an Edwards Acumen IQ transducer attached to the radial arterial catheter to measure dP/dt. Concurrent measurements of dP/dt were recorded from LV and radial arterial catheters before and after TAVR. Comparisons included Bland-Altman analysis, concordance changes following TAVR, Spearman correlations and linear regression analysis.

resultsBland-Altman analysis before TAVR demonstrated a bias between LV and radial measurements of 621 ± 396 mmHg/s with 95% limits of agreement from - 155 to 1397 mmHg/s. After TAVR, the bias decreased to 54 ± 412 mmHg/s, with 95% limits of agreement from - 754 to 862 mmHg/s. Concordance analysis of the changes following TAVR demonstrated an inverse relationship with a decrease in LV dP/dt and an increase in radial dP/dt observed in 73% of the patients. Correlation analysis before TAVR revealed Spearman r = 0.16 (95% CI: -0.06,0.37). After TAVR there was no significant change in the correlation coefficient, Spearman r = 0.09 (95% CI: -0.14, 0.31), but the slope of the best-fit regression line increased from 0.48 (95% CI: 0.44, 0.53) to 0.88 (95%CI: 0.80, 0.97).

conclusionSevere aortic stenosis impacts the relationship between LV and radial measurements of dP/dt. Following TAVR the correlation remains poor, but linear regression analysis suggests radial measurement of dP/dt may have the clinical utility to characterize directional changes of contractility within an individual patient.

trial registrationClinical trial Number: not applicable. The study protocol was reviewed by the institutional human subjects research committee, which waived the need for written, informed consent. As a quality improvement project designed to evaluate the clinical utility of radial arterial dP/dt measurement it was not registered on the ClinicalTrials.gov website.