Background:
Pulmonary hypertension (PH) due to left heart disease (LHD) is a major category of the disorder. We have recently reported that elevated pulmonary vascular resistance (PVR) in patients with post-capillary PH (pc-PH: defined as mean pulmonary arterial pressure (mPAP)≥25mmHg and pulmonary capillary wedge pressure (PCWP)>15mmHg) is associated with poor prognosis compared with those with no PH or pc-PH without elevated PVR. Although new treatment is required for targeting pulmonary vascular disease (PVD), thereis a concern about raising PCWP. In this study, we thus examined acute hemodynamic effects of inhaled nitric oxide (iNO) in patients with PH due to LHD and whether optimal heart failure (HF) treatment ameliorates pc-PH.
Methods:
We examined 60 consecutive pc-PH patients with chronic heart failure (63±14[SD] years, M/F 38/22, NYHA≥2) who underwent acute vasoreactivity test by iNO (40 ppm for 10 min) under right heart catheterization at our hospital from June 2011 to May 2014. Among them, 25 had valvular heart disease (VHD) and 35 had non-VHD. PVD (defined as PVR> 240dynes/s/cm
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) was noted in 18. We also evaluated right ventricular systolic pressure (RVSP) by echocardiography after optimization of HF treatment such as medications and valvular surgery.
Results:
iNO significantly decreased mPAP (-1.7±0.5 mmHg; P<0.01) and PVR (-66 ±14dyne/s/cm
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, P<0.01) without altering cardiac output. iNO significantly increased PCWP (1.3±0.5 mmHg, P=0.01) only in non-VHD patients, while it significantly increased mean arterial pressure and systemic vascular resistance in VHD patients than in non-VHD patients (both P<0.05). Pc-PH patients with PVD were re-classified as having pc-PH without PVD in 9 and no PH in 1. Eight patients remained pc-PH with PVD. After the optimal medical treatment for 7.6 months, RVSP was significantly decreased in both non-VHD and VHD patient (-8±3mmHg, P=0.04, -19±8mmHg, P=0.01, respectively). However, in non-VHD group, significant reduction in RVSP was noted only in pc-PH patients without PVD (-8±3mmHg, P=0.03).
Conclusions:
These results indicate that elevated PVR in patients with pc-PH and non-VHD could be a novel therapeutic indication for NO-related pulmonary vasodilators in the current practice of HF.
The pathophysiology of pulmonary hypertension in left heart disease