A 60-year-old male with a history of essential hypertension and a ten year history of paroxysmal atrial fibrillation (AF) presents with several weeks of progressive dyspnea on exertion and orthopnea. The physical exam was remarkable for an elevated jugular venous pulsation and an irregular rhythm. Electrocardiography and chest x-ray were performed (see Figures 1 and 2). Echocardiography showed a left ventricular ejection fraction of 62% (normal > 60%), with moderate right ventricular enlargement and moderately decreased systolic function. Tricuspid regurgitation velocity was 3.6 meters/second consistent with a calculated pulmonary artery systolic pressure of 81 mmHg (using an estimated right atrial pressure of 15 mmHg).
Two years ago he underwent a pulmonary vein isolation ablation for the treatment of AF and at that time echocardiography showed a moderately enlarged left atrium but no other abnormalities. Treatment was initiated with intravenous diuresis and his symptoms improved. Pulmonary CT angiogram was normal without evidence of pulmonary embolism or pulmonary vein stenosis. Coronary angiography showed no obstructive coronary artery disease. A right-heart catheterization was performed which showed a mean pulmonary artery pressure of 34 mmHg and a pulmonary vascular resistance of 3.3 Wood units.
Three weeks later he returned to clinic with continued symptoms of dyspnea. He remained in atrial fibrillation. Overnight oximetry was performed at his home and suggested severe obstructive sleep apnea (OSA), with 26% of measurements below 90% oxygen saturation. A polysomnogram was performed revealing severe OSA with an apnea-hypopnea index of 26.1/hour.
What is the next most appropriate step in the management of this patient?
The correct answer is: B. Initiaton of nocturnal positive airway pressure therapy and fluoroscopy of the diaphragm.
In this case, the patient presented for heart failure with preserved ejection (HFpEF) and was diagnosed with mild pulmonary arterial hypertension (PAH) and later severe OSA. The patient needs to be initiated on positive airway pressure therapy to prevent worsening of pulmonary hypertension (PH) and right ventricular function. Furthermore, given the elevated right hemidiaphragm in the setting of previous pulmonary vein isolation for AF, fluoroscopy of the diaphragm is indicated. In this patient, fluoroscopy of the diaphragm revealed markedly decreased right hemidiaphragm motion, consistent with paralysis. The patient was initiated on nocturnal bilevel positive airway pressure.
This case illustrates several important points on the diagnosis of both PAH and OSA. The patient presented with heart failure and a preserved ejection fraction (HFpEF), and echocardiography showed an elevated pulmonary artery systolic pressure. PH is commonly identified by echocardiography in patients with HFpEF, affecting 83% of patients in a community-based study of 244 patients.1 In general, PH in these patients has been correlated to "post-capillary" elevation of filling pressures from left ventricular diastolic dysfunction.2 Guidelines from the European Society of Cardiology specify that PH is likely when the echocardiogram shows an elevated tricuspid regurgitation velocity (> 3.5 meters/second) or pulmonary artery systolic pressure > 50 mmHg.3 Abbas and colleagues have shown that a tricuspid regurgitation velocity to right ventricular outflow tract velocity-time integral ratio of greater than 0.175 (0.55 in this case) has a sensitivity of 77% to identify patients with a pulmonary vascular resistance greater than 2 Wood units,4 which may be helpful to identify patients with PAH.
The diagnostic accuracy of overnight oximetry varies by the type of device and the comorbidities of the patient.5 Importantly, the American Academy of Sleep Medicine guidelines recommend that portable monitors be used as an alternative to polysomnography only in patients with a high pretest probability of moderate to severe OSA and no comorbid pulmonary disease or heart failure. Thus, formal polysomnography was indicated in this patient.
The relationship between OSA and PH is complex. The prevalence of PH in patients with OSA is between 17 to 52%.6 The major issue is whether PAH is a result of OSA, or whether they are both due to a shared comorbidity such as pulmonary disease.7 However, positive airway pressure therapy has been shown to improve PAH is a small controlled trial.8
The patient in this case presented with AF, recurrent after a previous pulmonary vein isolation procedure. Recent data indicate that patients with untreated OSA have a higher rate of AF recurrence after an ablation procedure (hazard ratio of 2.4).9 Our patient was also found to have paralysis of the diaphragm. Paralysis of the diaphragm, especially of the right hemidiaphragm, is a known, albeit rare complication of pulmonary vein isolation for AF. The incidence in the literature has been reported as 0.5%.10 The patient was referred for plication of the diaphragm, which has been shown to decreased dyspnea and improve pulmonary function tests.11
Lam CSP, Roger VL, Rodeheffer RJ, Borlaug BA, Enders FT, Redfield MM. Pulmonary hypertension in heart failure with preserved ejection fraction: a community-based study. J Am Coll Cardiol 2009;53:1119–26.
Bouchard JL, Aurigemma GP, Hill JC, Ennis CA, Tighe DA. Usefulness of the pulmonary arterial systolic pressure to predict pulmonary arterial wedge pressure in patients with normal left ventricular systolic function. Am J Cardiol 2008;101:1673–76.
Galiè N, Hoeper MM, Humbert M, et al. Guidelines for the diagnosis and treatment of pulmonary hypertension: 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). Eur Heart J 2009;30:2493–537.
Abbas AE, Fortuin FD, Schiller NB, Appleton CP, Moreno CA, Lester SJ. A simple method for noninvasive estimation of pulmonary vascular resistance. J Am Coll Cardiol 2003;41:1021–27.
Collop NA, Anderson WM, Boehlecke B, et al. Clinical guidelines for the use of unattended portable monitors in the diagnosis of obstructive sleep apnea in adult patients. J Clin Sleep Med 2007;3:737–47.
Golbin JM, Somers VK, Caples SM. Obstructive Sleep Apnea, Cardiovascular Disease, and Pulmonary Hypertension. Proc Am Thorac Soc 2008;5:200–6.
Chaouat A, Weitzenblum E, Krieger J, Oswald M, Kessler R. Pulmonary hemodynamics in the obstructive sleep apnea syndrome. Chest 1996;109:380–86.
Arias MA. Pulmonary hypertension in obstructive sleep apnoea: effects of continuous positive airway pressure: A randomized, controlled cross-over study. Eur Heart J 2005;27:1106–13.
Fein AS, Shvilkin A, Shah D, et al. Treatment of obstructive sleep apnea reduces the risk of atrial fibrillation recurrence after catheter ablation. J Am Coll Cardiol 2013;62:300–5.
Sacher F, Monahan KH, Thomas SP, et al. Phrenic nerve injury after atrial fibrillation catheter ablation. J Am Coll Cardiol 2006;47:2498–2503.
Freeman RK, Van Woerkom J, Vyverberg A, Ascioti AJ. Long-term follow-up of the functional and physiologic results of diaphragm plication in adults with unilateral diaphragm paralysis. Ann Thorac Surg 2009; 88: 1112–7.