Adaptive servoventilation for treatment of sleep-disordered breathing in heart failure: a systematic review and meta-analysis

Abstract

Background: Adaptive servoventilation (ASV) has demonstrated efficacy in treating sleep-disordered breathing (SDB) in patients with heart failure (HF), but large randomized trials are lacking. We, therefore, sought to perform a systematic review and meta-analysis of existing data.

Methods: A systematic search of the PubMed database was undertaken in March 2012. Publications were independently assessed by two investigators to identify studies of ≥ 1-week duration that compared ASV to a control condition (ie, subtherapeutic ASV, continuous or bilevel pressure ventilation, oxygen therapy, or no treatment) in adult patients with SDB and HF. Mean, variability,and sample size data were extracted independently for the following outcomes: apneahypopnea index (AHI), left ventricular ejection fraction (LVEF), quality of life (SF-36 Health Survey; Medical Outcomes Trust), 6-min walk distance, peak oxygen consumption ( VO 2 ) % predicted, and ventilatory equivalent ratio for CO 2 ( VE / Vco 2 ) slope measured during exercise. Random effects meta-analysis models were applied.

Results: Fourteen studies were identified (N = 538). Comparing ASV to control conditions, the weighted mean difference in AHI ( -14.64 events/h; 95% CI, -21.03 to - 8.25) and LVEF (0.40;95% CI, 0.08-0.71) both significantly favored ASV. ASV also improved the 6-min walk distance,but not peak O 2 % predicted, VE / VCO 2 slope, or quality of life, compared with control conditions.

Conclusions: In patients with HF and SDB, ASV was more effective than control conditions in reducing the AHI and improving cardiac function and exercise capacity. These data provide a compelling rationale for large-scale randomized controlled trials to assess the clinical impact of ASV on hard outcomes in these patients.

Figure 1.

Literature exclusion flowchart. Each publication was independently assessed and excluded in order by participants, intervention, comparator, outcome(s), and study design, with 14 studies remaining. ASV = adaptive servoventilation; BPAP = bilevel pressure ventilation; HF = heart failure; V_E/V_CO2 = ventilatory equivalent ratio for CO₂; VO₂ = oxygen consumption.

Figure 2.

Forest plot of AHI data in parallel studies. Each publication is represented by a square, the horizontal position of which represents the effect size, and error bars, which represent the 95% CI. All squares lie on the left of the null effect vertical line (mean difference of 0), indicating that all studies found a greater reduction in AHI with ASV compared with the control arm. The size of each square is proportional to the weight of each study in the pooled analysis, also listed as a percentage. The diamond represents the meta-analysis: the apex is the weighted mean difference (−14.64 events/h), and the width is the 95% CI (−21.03-−8.25 events/h). The width of the diamond does not cross the null effect vertical line, so the difference is statistically significant (P = .0001). AHI = apnea-hypopnea index. See Figure 1 legend for expansion of other abbreviation.

Figure 3.

Forest plot of LVEF data in parallel studies. Each publication is represented by a square, the horizontal position of which represents the effect size, and error bars, which represent the 95% CI. Squares lying to the right of the null effect vertical line (mean difference of 0) are those that found a greater increase in LVEF with ASV compared with the control arm. The size of each square is proportional the weight of each study in the pooled analysis, also listed as a percentage. The diamond represents the meta-analysis: the apex is the weighted mean difference (0.40), and the width is the 95% CI (0.08-0.71). The width of the diamond does not cross the null effect vertical line, so the difference is statistically significant (P = .01). LVEF = left ventricular ejection fraction. See Figure 1 legend for expansion of other abbreviation.