Diuretics in obstructive sleep apnea with diastolic heart failure.

BACKGROUND: Upper airway edema might contribute to pharyngeal collapsibility and account for the high prevalence of obstructive sleep apnea (OSA) in patients with heart disease. The aim of this study was to evaluate if intensive unloading with diuretics improves sleep-disordered breathing and increases pharyngeal caliber in patients with severe OSA and diastolic heart failure. METHODS: Fifteen patients with severe OSA, hypertension, and diastolic heart failure were hospitalized to receive IV furosemide, 20 mg, and spironolactone, 100 mg, bid for 3 days. Polysomnography was performed for assessment of apnea-hypopnea index (AHI), acoustic pharyngometry was performed for assessment of the oropharyngeal junction (OPJ) area, and forced midinspiratory flow (FIF(50)), forced midexpiratory flow (FEF(50))/FIF(50) percentage, and exhaled nitric oxide (FeNO) were measured before and after diuretic treatment. RESULTS: Diuretic treatment produced a significant decrease in body weight, BP, and AHI (from 74.89 +/- 6.95 to 57.17 +/- 5.40/h, p < 0.001), associated with an improvement in OPJ area (from 1.33 +/- 0.10 to 1.78 +/- 0.16 cm(2), p = 0.007), FIF(50) (from 3.16 +/- 0.4 to 3.94 +/- 0.4 L/s, p = 0.006), and FEF(50)/FIF(50) percentage (from 117.9 +/- 11.8 to 93.15 +/- 10.1%, p = 0.002). Weight loss was significantly related to the decrease of AHI (R = 0.602; p = 0.018), to the increase of FIF(50) (R = 0.68; p = 0.005), and to the decrease of FEF(50)/FIF(50) (R = 0.635; p = 0.011). CONCLUSIONS: These findings suggest that pharyngeal edema contributes to sleep-disordered breathing in obese patients with severe OSA, hypertension, and diastolic heart failure. Upper airway edema may contribute to the frequent occurrence of OSA in patients with heart disease.

Angiotensin-converting enzyme inhibitors and obstructive sleep apnea.

Angiotensin-converting enzyme (ACE) inhibitors may induce cough and rhinopharyngeal inflammation. Obstructive sleep apnea (OSA) is characterized by upper airway inflammation. We describe a patient who, during enalapril treatment, developed cough, upper airway symptoms, and diurnal sleepiness, with an increased number of obstructive apnea-hypopnea episodes (apnea-hypopnea index [AHI], 25) during sleep. Her symptoms and AHI improved 1 month after enalapril was discontinued and diuretic therapy (hydrochlorothiazide-spironolactone) was initiated. Similar findings were observed in 4 other patients with OSA who had ACE inhibitor-induced cough. The mean +/- SD AHI was 33.8+/-21.0 during enalapril treatment and 20.0+/-17.0 after withdrawal of this drug (P = .04). Exhaled nitric oxide, a marker of airway inflammation, was increased during enalapril treatment (15.0 +/- 4.3 parts per billion) and decreased after discontinuation of this drug (9.0 +/- 2.6; P = .03). No significant difference in the AHI and exhaled nitric oxide was observed in 4 patients with OSA who did not experience cough, before or after withdrawal of ACE inhibitor treatment. These findings suggest that ACE inhibitor treatment may contribute to OSA by inducing upper airway inflammation.

Myocardial viability after primary coronary angioplasty: low-dose dobutamine stress echocardiography versus myocardial contrast echocardiography.

BACKGROUND: Successful reperfusion therapy in patients with acute myocardial infarction (AMI) improves survival. Indeed, after AMI myocardial dysfunction may be reversible (hibernating or stunned myocardium). Low-dose dobutamine stress echocardiography (LDDSE) provides us with the possibility of evaluating viable myocardial segments, while myocardial contrast echocardiography (MCE) allows the study of the microcirculation in the same myocardial areas. The aim of our study was to compare LDDSE and MCE, in the prediction of the recovery of segments in patients with AMI who were submitted to primary coronary angioplasty (PTCA). METHODS: We studied 14 patients with AMI. Both LDDSE and MCE with Levovist were performed after primary PTCA. The viability gold standard was a recovery of contractility detected at echocardiography 2 months later. RESULTS: For LDDSE, the sensitivity was 91%, the specificity 71% and the positive and negative predictive values were 93 and 64% respectively. For MCE, the sensitivity was 94%, the specificity 44%, the positive predictive value 89%, and the negative predictive value 59%. Two tests agreed in 81% of the cases. Stress echocardiography and contrast echocardiography agreed in 81% of cases. CONCLUSIONS: LDDSE has a very good positive accuracy, it has an acceptable negative predictive value and is relatively cheap. On the other hand, MCE has a good positive accuracy, but a low negative accuracy and carries a high cost. The integration of these two tests, which are too expensive in clinical practice, could improve our comprehension of the post-PTCA pathophysiology.

Exhaled nitric oxide during exercise and dobutamine stress echocardiography in patients with mitral stenosis.

BACKGROUND: Pulmonary hypertension (PH) is an important limiting factor of exercise tolerance in patients with mitral stenosis (MS). We wished to investigate the relationship between respiratory nitric oxide (NO), a potent vasodilator, and exercise tolerance in patients with moderate MS. In the same patients, we wondered whether acute change in pulmonary hemodynamics could affect respiratory NO. METHODS: Ten patients with moderate MS (valve area 1.4+/-0.2 cm(2)) were studied at rest, during incremental cycle ergometry exercise, and during dobutamine stress echocardiography (DSE). The concentration of NO in exhaled air (FE(NO)) and NO output (V'(NO)) were measured at baseline, at the end of exercise, and at the end of DSE. Eight healthy subjects served as normal controls for NO output during exercise. RESULTS: During exercise, FE(NO) decreased both in patients and in controls, while V'(NO) increased in both. At the end of exercise, both VO(2) max and V'(NO) were significantly higher in controls than in patients. The increase in V'(NO) during exercise was significantly correlated with VO(2) max, both in patients and in controls. During DSE, cardiac output (CO), pulmonary artery pressure (PAP), and mitral valve gradient increased. No changes in mean FE(NO), V'(NO), or ventilation were observed during DSE. There was a significant inverse correlation between FE(NO) and mitral valve gradient at the end of DSE. CONCLUSIONS: In patients with moderate MS, exercise performance is correlated with respiratory NO output. In the same patients, during DSE, the increase in CO, which is not accompanied by an increase in ventilation, is not associated with an increase in respiratory V'(NO).