METHODS: We investigated the effect of 5 weeks of AZA (250 mg bid) versus placebo on maximal load during incremental cycling ramp exercise in patients with PVD studied in a randomized controlled, double-blind, crossover design, separated by > 2 weeks of washout.
RESULTS: Twenty-five patients (12 pulmonary arterial hypertension, 13 CTEPH, 40% women, age 62 ± 15 years) completed the trial according to the protocol. Maximum load was similar after 5 weeks of AZA versus placebo (113 ± 9 vs. 117 ± 9 watts [W]), mean difference -4 W (95% CI: -9 to 1, p = 0.138). With AZA, maximum (max)-exercise partial pressure of O2 (PaO2) was significantly higher by 1.1 kPa (95% CI: 0.5-1.8, p = 0.003), while arterial pH and partial pressure of CO2 were significantly lower. Gas exchange threshold was reached at a higher load with AZA (108 ± 8 W vs. 97 ± 8 W) and was therefore delayed by 11 W (95% CI: 3-19, p = 0.013), while the ventilatory equivalent for O2 and CO2 were significantly higher at both the max-exercise and gas exchange threshold with AZA versus placebo.
CONCLUSIONS: AZA for 5 weeks did not significantly change maximum exercise capacity in patients with PVD despite a significant increase in PaO2. The beneficial effects of increased blood oxygenation may have been diminished by increased ventilation due to AZA-induced metabolic acidosis and increased dyspnea.
方法:我们研究了在随机对照研究中,在PVD患者中,在递增循环斜坡运动期间,AZA(250mgbid)与安慰剂对最大负荷的影响,双盲,交叉设计,分开2周的冲洗。
结果:25例患者(12例肺动脉高压,13CTEPH,40%的女性,年龄62±15岁)根据方案完成试验。AZA与安慰剂治疗5周后的最大负荷相似(113±9vs.117±9瓦[W]),平均差-4W(95%CI:-9至1,p=0.138)。有了AZA,最大(max)-运动氧分压(PaO2)显着升高1.1kPa(95%CI:0.5-1.8,p=0.003),而动脉pH值和CO2分压显著降低。AZA在较高的负载下达到了气体交换阈值(108±8W与97±8W),因此延迟了11W(95%CI:3-19,p=0.013),而与安慰剂相比,AZA在最大运动阈值和气体交换阈值下的O2和CO2通气当量均显着较高。
结论:AZA治疗5周并未显著改变PVD患者的最大运动能力,尽管PaO2显著升高。由于AZA诱导的代谢性酸中毒和增加的呼吸困难,增加的通气可能会减少血液氧合增加的有益作用。