経皮的冠動脈インターベンション(PCI)後の睡眠呼吸管理の重要性

The Importance of Managing Obstructive Sleep Apnea during Secondary Prevention in Patients after Percutaneous Coronary Intervention

要旨　目的：閉塞性睡眠時無呼吸(OSA)は様々な心血管疾患と関連することが報告されている．今回の研究目的は冠動脈疾患を有する患者のOSA合併率，またOSAの合併が予後に影響を与えるかどうか調査を行うことである．方法：経皮的冠動脈インターベンション(PCI)施行患者464名を対象に，OSAの合併率を調査した．また，OSAを合併しない群，合併する群，OSAに対し持続陽圧呼吸(CPAP)療法を施行した群の3群に分類し，PCI後5年間の心血管イベント発生率を比較した．結果：無呼吸低呼吸指数(AHI)15以上を睡眠呼吸障害と定義した場合，286名(65.3%)にOSAが合併していた．Kaplan-Meier法では，OSA合併群でPCI後の心血管イベント発生率が有意に高率であった．また，CPAP療法施行群は心血管イベント発症が有意に抑制された．結語：冠動脈疾患患者は高率にOSAを合併しており，予後にも悪影響を与えるため，冠動脈疾患二次予防のために十分な睡眠呼吸管理が必要である．

　Background:Several epidemiological and clinical studies have demonstrated that obstructive sleep apnea(OSA)increases cardiovascular morbidity and mortality. The aim of this study was to determine whether OSA might affect long-term outcomes after percutaneous coronary intervention(PCI).

　Methods:464 patients, who had undergone successful PCI for acute coronary syndrome or stable angina, were classified into three groups on the basis of the apnea-hypopnea index(AHI)and the application of continuous positive airway pressure(CPAP)in those with AHI＜15, AHI＞15, and taking CPAP treatment. In the 3 groups, the incidences of major adverse cardiac events(MACE)were measured during the five years after PCI. MACE was defined as cardiac death, non-fatal myocardial infarction, new lesions and restenosis.

　Results:The median follow-up duration was 34 months. Kaplan-Meier analysis demonstrated that patients with AHI＞15(n＝171)had a higher incidence of MACE after PCI than patients with AHI＜15(n＝220). However, CPAP treatment(n＝73)reduced incidences of MACE(Logrank test:P＜0.001). In addition, Cox proportional hazards analysis indicated that AHI was an independent risk factor of MACE after PCI(OR＝1.032, 95%CI＝1.022-1.043, p＜0.001), but age, body mass index, diabetes mellitus, smoking, and medication were not associated. Furthermore, the plasma concentration of C-reactive protein(CRP)had significantly decreased after CPAP.

　Conclusion:A high percentage of patients with coronary artery disease had OSA,and the OSA was an independent predictor of cardiovascular events after PCI. Also,CPAP is considered useful in the prevention of cardiovascular events. Therefore,we should pay attention to sleep apnea in patients with coronary artery disease.