Abstract 11257: Physiologic Quantification of the Diastolic Pressure Difference Re-classifies Pulmonary Hypertension in Patients With Advanced Heart Failure

Abstract

Introduction: Assessment of pulmonary hypertension (PH) by right heart catheterization remains important in the evaluation of advanced heart failure (HF) patients being considered for cardiac transplant. Delineating ‘isolated’ post-capillary PH (Ipc-PH) and ‘combined’ pre- and post-capillary PH (Cpc-PH) remains a challenge in hemodynamic assessment, as the usual practice of calculating the diastolic pressure difference (DPD) has limitations pre-disposing it to underestimation. Hypothesis: QRS-gated calculation of the DPD (QRS-DPD), specific to late diastole when the DPD is expected to be small, will reduce the frequency of negative DPD values, and re-classify a subset of patients as Cpc-PH. Methods: Advanced HF patients (n = 136, median age = 56 years) referred for right heart catheterization within the clinical evaluation for cardiac transplant candidacy were studied. Hemodynamics were analyzed offline and measurements were averaged over 8-10 beat intervals. Automated measurements of systolic/diastolic/mean pulmonary artery pressure (sPAP/dPAP/mPAP), and mean pulmonary artery wedge pressure (mPAWP) were generated as per usual practice. Usual practice DPD (UP-DPD) was calculated as [dPAP – mPAWP]. Within the same intervals, pulmonary artery pressure (QRS-PAP) and pulmonary artery wedge pressure (QRS-PAWP) gated to the QRS-onset were manually measured for each beat and averaged. QRS-DPD was calculated as [QRS-PAP – QRS-PAWP]. Results: The mean UP-DPD was 0 ± 5 mmHg, and was <0 mmHg in 61/136 cases (45%). The mean QRS-DPD was 5 ± 4 mmHg, and was <0 mmHg in 10/136 cases (7%) (p < 0.05). Of 136 cases, 67 (49%) demonstrated mPAP ≥25 mmHg and mPAWP >15 mmHg. Using the UP-DPD classified 4/67 as Cpc-PH (DPD ≥7 mmHg), while the QRS-DPD classified 22/67 as Cpc-PH (p < 0.05). Conclusions: QRS-gated measurements increase the calculated DPD, and reduce the frequency of negative values. In advanced HF patients with PH, up to 25% of Ipc-PH cases may be re-classified as Cpc-PH.