Estimating Right Ventricular Stroke Work and the Pulsatile Work Fraction in Pulmonary Hypertension
| Autor: | Nicolas Creuze, Denis Chemla, Gérald Simonneau, Florence Parent, Susana Hoette, Vincent Castelain, Marc Humbert, Philippe Hervé, Kaixian Zhu, Yves Papelier |
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| Rok vydání: | 2013 |
| Předmět: |
Adult
Male Pulmonary and Respiratory Medicine medicine.medical_specialty Cardiac output Heart Ventricles Hypertension Pulmonary Rest Pulsatile flow Critical Care and Intensive Care Medicine Right ventricular Stroke work Heart Rate medicine.artery Internal medicine Heart rate medicine Humans Cardiac Output Exercise physiology Exercise Retrospective Studies business.industry Models Cardiovascular Stroke Volume Stroke volume Middle Aged medicine.disease Pulmonary hypertension Pulsatile Flow Pulmonary artery Cardiology Female Cardiology and Cardiovascular Medicine business |
| Zdroj: | Chest. 143:1343-1350 |
| ISSN: | 0012-3692 |
| DOI: | 10.1378/chest.12-1880 |
| Popis: | The mean pulmonary artery pressure (mPAP) replaces mean systolic ejection pressure (msePAP) in the classic formula of right ventricular stroke work (RVSW) = (mPAP - RAP) × stroke volume, where RAP is mean right atrial pressure. Only the steady work is thus taken into account, not the pulsatile work, whereas pulmonary circulation is highly pulsatile. Our retrospective, high-fidelity pressure study tested the hypothesis that msePAP was proportional to mPAP, and looked at the implications for RVSW.Eleven patients with severe, precapillary pulmonary hypertension (PH) (six patients with idiopathic pulmonary arterial hypertension and five with chronic thromboembolic PH; mPAP = 57 ± 10 mm Hg) were studied at rest and during mild to moderate exercise. Eight non-PH control subjects were also studied at rest (mPAP = 16 ± 2 mm Hg). The msePAP was averaged from end diastole to dicrotic notch.In the full data set (53 pressure-flow points), mPAP ranged from 14 to 99.5 mm Hg, cardiac output from 2.38 to 11.1 L/min, and heart rate from 53 to 163 beats/min. There was a linear relationship between msePAP and mPAP (r² = 0.99). The msePAP matched 1.25 mPAP (bias, -0.5 ± 2.6 mm Hg). Results were similar in the resting non-PH group and in resting and the exercising PH group. This implies that the classic formula markedly underestimates RVSW and that the pulsatile work may be a variable 20% to 55% fraction of RVSW, depending on RAP and mPAP. At rest, RVSW in patients with PH was twice as high as that of the non-PH group (P.05), but pulsatile work fraction was similar between the two groups (26 ± 4% vs 24 ± 1%) because of the counterbalancing effects of high RAP (11 ± 5 mm Hg vs 4 ± 2 mm Hg), which increases the fraction, and high mPAP, which decreases the fraction.Our study favored the use of an improved formula that takes into account the variable pulsatile work fraction: RVSW = (1.25 mPAP - RAP) × stroke volume. Increased RAP and increased mPAP have opposite effects on the pulsatile work fraction. |
| Databáze: | OpenAIRE |
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