What is the clinical evidence from this study?

Study design: Observational. Population: Obstructive Sleep Apnoea Syndrome (n=26). Intervention: Nasal continuous positive airway pressure (nCPAP) vs. Baseline (before treatment) and overweight non-apnoeic normal subjects. Primary outcome: Isovolumic relaxation time (IVRT) (p=<0.05).

January 1, 2000

Left Ventricular Function in Patients with Obstructive Sleep Apnoea Syndrome before and after Treatment with Nasal Continuous Positive Airway Pressure

Q: What are the key findings of this study?

Treatment with nCPAP for 12-14 weeks significantly improved left ventricular diastolic function (IVRT 85.6 vs 94.3 ms, p<0.05) and reduced diastolic blood pressure in patients with OSA.

Key Result

Treatment with nCPAP for 12-14 weeks significantly improved left ventricular diastolic function (IVRT 85.6 vs 94.3 ms, p<0.05) and reduced diastolic blood pressure in patients with OSA.

Study Design

Type

Observational (n=26)

Structured PICO

Does nasal continuous positive airway pressure (nCPAP) improve left ventricular diastolic function and blood pressure in patients with obstructive sleep apnoea syndrome?

Population

15 patients (3 women, 12 men) with obstructive sleep apnoea syndrome (apnoea/hypopnoea index >15) and no history of systemic hypertension, coronary artery disease, myocardial, pericardial or valvular problems, asthma or chronic obstructive pulmonary disease. 11 overweight non-apnoeic normal subjects matched for age were used as the control group.

Intervention

Nasal continuous positive airway pressure (nCPAP) for 12-14 weeks

Comparator

Baseline values before treatment, and 11 overweight non-apnoeic normal subjects

Outcome

Left ventricular function parameters (IVRT, E/A ratio, shortening fraction, IVST, PWT) and blood pressure (systolic and diastolic, daytime and night-time) measured by echocardiography and ambulatory BP monitoringsurrogate

Treatment with nCPAP for 12-14 weeks significantly improves left ventricular diastolic function and reduces diastolic systemic hypertension in patients with obstructive sleep apnoea syndrome.

Main Result

Absolute Event Rate: 85.6% vs 94.3%

p-value: p=<0.05

Abstract

BACKGROUND: Previous studies have yielded disparate results regarding the effect of obstructive sleep apnoea (OSA) syndrome on left ventricular (LV) function. OBJECTIVES: In order to clarify this, we performed a prospective study investigating OSA patients with no history of systemic hypertension, coronary artery disease, myocardial, pericardial or valvular problems, asthma or chronic obstructive pulmonary disease before and after treatment with nasal continuous positive airway pressure (nCPAP). METHODS: Fifteen patients (3 women, 12 men) with an apnoea/hypopnoea index >15 (mean +/- SD = 52 +/- 21) were studied with complete polysomnography, ambulatory blood pressure monitoring, M-mode two-dimensional echocardiography and pulsed Doppler echocardiography in two phases, i.e. before and after 12-14 weeks of nCPAP therapy. We measured systolic and diastolic blood pressure (BP) separately in the daytime and night-time, isovolumic relaxation time (IVRT), the ratio of peak early filling velocity (E) to peak late velocity (A) diastolic transmitral flow (E/A), posterior wall thickness (PWT) and septal thickness (IVST). The shortening fraction (SF) was also calculated. Eleven overweight non-apnoeic normal subjects matched for age were used as the control group. RESULTS: Our results showed that the patient group exhibited, before treatment, LV diastolic, but not systolic, dysfunction compared with the normal group (IVRT = 94.3 +/- 11.6 ms, p < 0.05; E/A = 0.94 +/- 0.26, p < 0.02; SF = 39.9 +/- 4.1%, not significant (NS); IVST = 9.9 +/- 1.2 mm, NS; PWT = 8.3 +/- 1.2 mm, NS). Moreover, the patient group developed diastolic hypertension both in the daytime and night-time (BP/diastolic/daytime = 93.3 +/- 9.2 mm Hg, BP/diastolic/night-time = 90.3 +/- 10.7 mm Hg). After 12-14 weeks of nCPAP treatment (no change in body mass index), significant improvement in LV diastolic function and a drop in blood pressure were noticed (IVRT = 85.6 +/- 8.8 ms, p < 0.05; E/A = 1.07 +/- 0.3, p < 0.05; BP/diastolic/daytime = 86.3 +/- 5.5 mm Hg, p < 0.02; BP/diastolic/night-time = 83.9 +/- 8. 6 mm Hg, p < 0.05) in our patient group. CONCLUSIONS: We conclude that repetitive apnoeas/hypopnoeas are very important factors in the development of both LV diastolic dysfunction and diastolic systemic hypertension in patients with OSA syndrome. Treatment with nCPAP leads to significant improvement in both ventricular function and systemic hypertension.

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