Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties: Patient Characteristics

A total of 57 patients, 35 with PAH and 22 with CTEPH, were included in the study. Patient characteristics are presented in Table 1. Patients with CTEPH were on average older than those with PAH, and had lower CI, Sa02, and mixed venous saturation (Sv02). Other parameters did not vary significantly between the two groups. yaz birth control
iNO and iILO significantly decreased MPAP and PVR in both PAH and CTEPH patients, and to a comparable extent. The response to iNO and iILO, as well as the response between patients with PAH and those with CTEPH, were not statistically significant (Table 2, Fig 1).

Pooling all patients, the correlation coefficient between iNO and iILO for the change in MPAP and PVR was 0.37 (p < 0.01) and 0.46 (p < 0.01), respectively. iILO but not iNO increased CI significantly in both the PAH (p = 0.008) and the CTEPH patients (p = 0.001). However, the difference between the two groups was not statistically significant (p = 0.57). Both vasodilators increased Sv02 significantly in both PAH and CTEPH patients (Fig 1). In both groups, the effect of both iNO and iILO on Sa02 was small and of questionable clinical relevance.
Based on the criterion of a MPAP or PVR reduction of > 20%, more patients could be classified as pressure responders (p = 0.006) or resistance responders (p = 0.03) to iILO than to iNO (Table 3). Using the proposed positive response criteria with an absolute MPAP decrease of at least 10 mm Hg and < 40 mm Hg along with stable CI, the incidence of iNO responders remained nearly unchanged (5% vs 7%, respectively), whereas the number of iILO responders decreased from 21 to 12% (p = <0.001), the difference between iNO and iILO responders was still significant (p = 0.003) [Table 3]. In the pooled groups of patients, a positive response to iILO was associated with a concurrent positive response to iNO in 75% of the patients. Conversely, a positive response to iNO was present only in 25% of the patients with a positive response to iILO. The effect of both vasodilators was similar in the patients with PAH and those with CTEPH (Table 3).

Table 1—Baseline Characteristics

Characteristics PAH Patients (n = 35) CTEPH Patients (n = 22) p Value
Age, yr 49 (25) 65 (16) < 0.001
BMI, kg/m2 25.5 (5.4) 25 (4.7) 0.84
NYHA/WHO classt
II 4(11) 1(5)
III 23 (66) 13 (59)
IV 8 (23) 8 (36)
6MWD, m 438(110) 402(185) 0.32
Borg scale dyspnea score 4 (9) 4(3) 0.64
SPAP, mm Hg 76 (31) 73 (19) 0.43
DPAP, mm Hg 36 (15) 30 (14) 0.06
MPAP, mm Hg 48 (23) 43 (16) 0.14
PP, mm Hg 39 (16) 41 (15) 0.76
PPf 0.809 (0.37) 0.94 (0.31) 0.21
PVR, dyne. s. m—5 785 (766) 800 (644) 0.91
CI, L/min/m2 2.1 (1.4) 1.8 (0.7) 0.01
Sao2, % 94.1 (4) 92.8 (4) 0.04
Svo2(%) 63(11) 58 (10) 0.02

Table 2—Changes in Different Hemodynamic Variables Associated With Acute Vasoreactivity Testing

Variables PAH Patients, % (n = 35) CTEPH Patients, % (n = 22) pValuet
MPAP
INO 5)CC

1

3) 0.90
IILO —6.3 (15)! —8.3 (13)! 0.72
p value§ 0.29 0.68
PVR
INO — 16.8 (19)! — 16.3 (17)! 0.67
IILO 4)(4

—16.3 (20)! 0.48
p value§ 0.91 0.97
CI
INO + 1 (19) +6.1 (18) 0.44
IILO +9 (41) + 16.3 (19)! 0.64
p value§ 0.92 0.18
Svo2
INO +2.3 (6) +4.7 (10) 0.29
IILO +1.7 (9) +1.8 (4) 0.50
p value§ 0.78 0.03

Table 3—Responders to Vasoreactivity Testing According to Different Definition Criteria

Positive Response Criteria All Patients (n = 57) PAH Patients (n = 35) CTEPH Patients (n = 22) pValuet
a 20% decrease in MPAP
iNO 4(7) 2(6) 2 (9) 0.63
Iloprost 12! (21) 8! (23) 4 (18) 0.67
a 20% decrease in PVR
iNO 23 (41) 13 (37) 10 (46) 0.53
Iloprost 27 (48) 18 (52) 9(41) 0.44
a 10 mm Hg MPAP decrease to absolute < 40 mm Hg
iNO 3(5) 2 (6) 1 (6) 0.85
Iloprost 7 (12) 6! (17) 1 (5) 0.16

Figure-1

Figure 1. Values are given as medians and interquartile ranges. * = p < 0.05 compared to baseline; t = p < 0.01 compared to baseline.

This entry was posted in Respiratory Symptoms and tagged chronic thromboembolic pulmonary hypertension, pulmonary arterial hypertension, pulmonary hemodynamics, pulmonary vascular compliance, vasoreactivity testing.