American Journal of Respiratory and Critical Care Medicine

A 58-year-old woman was admitted for progressive exertional dyspnea and exhaustion. Right heart catheterization revealed a mild precapillary pulmonary hypertension at rest (mean pulmonary artery pressure, 27 mm Hg; pulmonary arterial wedge pressure, 6 mm Hg; pulmonary vascular resistance, 415 dyn⋅s⋅cm−5, cardiac index, 2.8 L⋅min−1⋅m−2; right atrial pressure, 6 mm Hg) and slightly reduced cardiac index (1). Periodic breathing without snoring had been reported by the husband. Standard laboratory-based respiratory polygraphy showed a central sleep apnea (CSA) with an apnea–hypopnea index of 22 per hour, a desaturation index of 31 per hour, and periodic breathing (Figure 1A). Mean and minimal nighttime oxygen saturation were decreased (92 and 76%). Daytime blood gases revealed hyperventilation and a slightly reduced oxygenation (Po2, 71.2 mm Hg; Pco2, 31.5 mm Hg; oxygen saturation, 95.5%). Cardiopulmonary exercise testing showed undulating breathing under exercise conditions. Left ventricular function was normal. The patient was treated with metoprolol and amlodipine for systemic arterial hypertension. There were no other comorbidities such as congestive left heart failure or central nervous system disorder and no drug intake as risk factors for CSA. Ventilation/perfusion scan and angiography showed chronic thromboembolic pulmonary hypertension (CTEPH) (1) (Figure 1B). Due to higher priority of CTEPH and severe exertional dyspnea, a planned polysomnography was delayed.

Pulmonary thromboendarterectomy (PEA) was performed (1). After the PEA, the patient noted markedly improved exercise tolerance and resolution of exhaustion with mPAP of 18 mm Hg and cardiac index of 3.3 L⋅min−1⋅m−2). Undulating breathing under exercise was resolved. Daytime blood gases, oxygen uptake, and O2 pulse under exercise, breathing efficacy, and minimal nighttime oxygen saturation improved. CSA and periodic breathing resolved completely after the PEA (apnea–hypopnea index, 0/h) (Figure 1C).

There is a high prevalence of Cheyne-Stokes respiration and CSA in patients with differently classified pulmonary hypertension (2). The complete resolution of CSA after PEA might be due to improved pulmonary artery pressure, cardiac index, and oxygenation as a result of improved right heart function. It may be speculated that this case could be a clue to pathophysiology of Cheyne-Stokes respiration/CSA with right heart impairment and failure being the driver of these symptoms. Even in patients with left heart failure, Cheyne-Stokes respiration/CSA might be due to right heart involvement.

When CSA is diagnosed in the absence of congestive left heart failure and central nervous system disorders or drug use, pulmonary hypertension should be considered, with search for CTEPH as a potentially curable disease.

1. Galié N, Hoeper MM, Humbert M, Torbicki A, Vachiery JL, Barbera JA, Beghetti M, Corris P, Gaine S, Gibbs JS, et al.; The Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS) endorsed by the International Society of Heart and Lung Transplantation (ISHLT). Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Heart J 2009;30:24932537.
2. Ulrich S, Fischler M, Speich R, Bloch KE. Sleep-related breathing disorders in patients with pulmonary hypertension. Chest 2008;133:13751380.
3. Held M, Meintz S, Baron S, Roth C, Wikens H, Schäfers HJ, Jany B. Zentrale Schlafapnoe bei Chronisch-thrombembolidcher Pulmonaler Hypertonie–Komplette Rückbildung nach pulmonaler Thrombendarteriektomie [abstract]. Pneumologie 2012;S1:S74.

Author Contributions: M.H., S.M., S.B., C.R., H.W., H.J.S., and B.J.: conception, interpretation of data, and drafting and final approval of the version to be published.

Author disclosures are available with the text of this article at


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