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Angiotensin-Converting Enzyme Gene Polymorphisms and Tissue Oxygenation During Exercise: Results

All values are presented as means ± SD. When multiple comparisons were made between groups, significant intergroup variability was first established with the Kruskal-Wallis test. The Mann-Whitney U test was then used for intergroup comparisons. The significance of correlations was evaluated by determining Spearman’s rank correlation coefficients. The significance level was set at p < 0.05.
The clinical characteristics for all 39 subjects with COPD are summarized in Table 1. The 14 patients with the II genotype, 12 patients with the ID genotype, and 13 patients with the DD genotype constituted well-matched subgroups with respect to age, baseline lung function, arterial blood gas data at rest or exercise, and hemodynamic data at rest. Additionally, the exercise level at which hemodynamics was definitively performed in each subject was comparable (maximal workload for patients with the II genotype, 69.9 ± 18.5 W; ID genotype, 65.8 ± 10.2 W; and DD genotype, 67.2 ± 15.3 W). However, the mean PAP after exercise was significantly higher in patients with the DD genotype (53.2 ± 3.9 mm Hg) than in those with the II genotype (40.6 ± 4.0 mm Hg, p < 0.0001) and the ID genotype (45.7 ± 5.9 mm Hg, p = 0.003). www.mycanadianpharmacy.com

The ratio of the change in oxygen delivery (Do2 ) to the increase in V02 during a constant-load exercise (ADo2/AV02) was significantly lower in patients with the DD genotype (1.5 ± 0.2) than in those with the II genotype (1.9 ± 0.3, p = 0.0006) and the ID genotype (1.7 ± 0.2, p = 0.037) [Fig 2]. Mixed venous oxygen tension (Pvo2) at rest did not differ significantly in all three subgroups. However, Pvo2 after exercise in patients with the DD genotype (23.5 ± 1.5 mm Hg) was significantly lower than in patients with the II genotype (26.7 ± 1.6 mm Hg, p = 0.0002) and the ID genotype (25.0 ± 2.0 mm Hg, p = 0.045). In addition, the change in plasma concentration of lactate during exercise (ALactate) was significantly higher in patients with DD genotype (33.3 ± 4.3 mmol/L) than in those with the II genotype (25.5 ± 3.6 mmol/L, p = 0.0002) and the ID genotype (28.8 ± 4.0 mmol/L, p = 0.029).
Fig2
Figure 2. The ratio of the change in Do2 to the increase in Vo2 (ADo^AVo2), Pvo2 after exercise, and ALactate during exercise in patients with the II, ID, and DD genotypes. Do2 (milliliters per minute) = (Qt) X(oxygen content) = Qt X (arterial oxygen content — mixed venous oxygen content).
Table 1—Clinical Characteristics of Study Patients

ACE Genotypes
III ID DD
Characteristics (n = 14) (n = 12) (n = 13)
Age, yr 60.9 (3.3) 65.6 (5.3) 62.2 (4.7)
Pao2, mm Hg 74.1 (9.3) 71.9(7.8) 72.8 (9.5)
FEVi, L 0.79 (0.22) 0.85 (0.28) 0.83 (0.21)
Mean PAP at rest, mm Hg 27.3 (2.1) 26.8 (3.3) 27.4 (2.7)
Mean PAP after exercise, mm Hg 40.6 (4.0)ft 45.7 (5.9)f 53.2 (3.9)
Pvo2 at rest, mm Hg 32.3(1.6) 32.8 (2.1) 32.6(1.9)