PULSE WAVEFORM CHARACTERISTICS VERSUS CONVENTIONAL BLOOD PRESSURES – POTENTIAL CLINICAL IMPACT: PP.31.247

Abstract

Background: Pulse waveform analysis (PWA) facilitates non-invasive determination of central blood pressures (central systolic blood pressure – CSBP and central pulse pressure – CPP) and waveform characteristics (Augmentation Index – AIx; AIx normalized for heart rate 75 – AIx 75; Pressure Augmentation – AP). Both have been shown to improve risk prediction, but their potential impact on management of hypertension in clinical practice has not been clarified. Methods: We performed PWA in 108 patients (58 men, 50.9 +/- 12.7 years) undergoing routine examinations including ambulatory blood pressure measurement (ABPM) for suspected or treated hypertension. CSBP, CPP, AIx, and AP > mean + 1 SD (based on published cohorts) were categorized as elevated. The relationships between office and ABPM blood pressures and PWA measures were compared, using t-test or CHI square test. Results: Mean office blood pressure was 149 / 92 mm Hg, mean day / night / 24 hour ABPM was 143/91, 129/79, and 140/88 mm Hg, respectively. Based on office blood pressure or ABPM, 81.5 or 86.1 % of patients were hypertensive. With respect to CSBP, CPP, AIX, and AP, 77.8, 50, 23.1, and 33.3 % were categorized as elevated. Patients with hypertension (office BP) had significantly (p < 0.05) higher values for CSBP, CPP, AIx 75, and AP, although overlap of categories was incomplete. E.g., 53.3 / 20 / 16.7 % of patients with office normotension and 87.2 / 61.5 / 39.7 % of patients with office hypertension had elevated CSBP / CPP / AP. Considering ABPM, patients with hypertension had significantly higher values of CSBP and AIx 75, although PWA categories did not differ. CSBP, CPP, AIx, AIx 75, and AP were not different across daytime ABPM categories, but patients with nighttime hypertension had significantly (p < 0.05) higher values of CSBP, CPP, AIx, AIx 75, and AP. ROC curve analysis revealed an AUC for detecting systolic nighttime hypertension with CSBP of 0.79 (p < 0.0001). Dipping pattern was associated with CSBP, CPP, and AP. Conclusion: Taking PWA characteristics into account would alter labelling of patients as normotensive or hypertensive and, thus, change management. The association between nighttime blood pressure and waveform characteristics is remarkable and deserves further study.