Introduction
Pulmonary hypertension (PH) is a pathophysiological condition characterized by elevated pressure in the pulmonary arteries, when the mean pulmonary artery pressure (mPAP) exceeds 20 mmHg and associated with right ventricular heart failure [1]. PH management particularly challenging during pregnancy. The physiological changes that occur during pregnancy can exacerbate PH and complicate treatment strategies [2, 3]. The World Health Organization (WHO) classifies PH based on the underlying causes and clinical manifestations, categorizing many conditions associated with PH as high-risk for pregnant women. These risks can approach 100 %, making pregnancy generally contraindicated [2, 3]. However, some patients may choose to continue their pregnancies, necessitating intensive therapy and anesthetic support during the peripartum period.
PH is classified into five groups according to its causes. The most common form encountered during pregnancy is pulmonary arterial hypertension (Group 1), followed by pulmonary venous hypertension (Group 2), which is associated with left heart chamber pathology. Other groups collectively account for about 8 % of PH cases during pregnancy [5]. Groups 1 and 2 differ essentially in their pathophysiological mechanisms, which determines differences in clinical progression. In arterial PH (PH Group 1), the primary stages of pathogenesis are spasm, obstruction or volumetric overload of the arterial part of the pulmonary circulation, leading to increases in pulmonary artery pressure and right heart chambers.
Venous PH (PH Group 2) results from elevated left atrial pressure, typically due to left heart disease. This leads to retrograde pressure transmission into the pulmonary venous system, ultimately causing increases in pulmonary artery pressure and right heart chambers.
Regardless of the underlying mechanism of pulmonary hypertension (PH), the clinical course during the peripartum period varies from uncomplicated vaginal delivery (VD) to cesarean section (CS) with preoperative management, invasive monitoring,and readiness for extracorporeal circulatory support or simultaneous cardiac surgical interventions [6]. A balanced assessment of the benefit/risk ratio of intraoperative invasive monitoring and hemodynamic pharmacological management, along with readiness for the implementation of circulatory support devices and rational use of hospital resources, necessitates the identification of high-risk patients requiring specialized care during the antenatal period.
Objective
To identify risk factors for adverse outcomes during peripartum period in patients with pulmonary arterial hypertension (PH Group 1) and pulmonary venous hypertension (PH Group 2), requiring the use of special monitoring, anesthetic management, and intensive care.
Research hypothesis
The clinical course of the peripartum period, as well as the rate and structure of complications, differs between patients with coexisting PH Group1 and Group 2.
Materials and methods
Single-center, retrospective, descriptive study of the peripartum period in patients with coexisting pulmonary hypertension (PH) Group 1 and Group 2 was based on the analysis of 242 delivery records from the Perinatal Center (PC) of the Clinic of Maternity and Childhood, Almazov National Medical Research Centre, Ministry of Health of Russia. All deliveries were carried out from January 2011 to February 2024 [5]. The study protocol was approved by the Local Ethics Committee (LEC) of the Almazov National Medical Research Centre (Extract No. 2006-23 from the LEC meeting protocol No. 06-23 dated June 13, 2023).
The following inclusion criteria were identified: systolic pulmonary artery pressure (sPAP) based on echocardiographic examination (ECHO) at any time point prior to delivery ≥ 35 mmHg; confirmed diagnosis of “Pulmonary Hypertension”; an established diagnosis that allows PH to be classified into group 1 or 2 according to the clinical classification of PH [1, 4]; delivery at the Almazov National Medical Research Center at a gestational age of 22 weeks or greater; observation in the adult anesthesiology and intensive care unit (AICU) of the PC during the antenatal and/or postpartum periods.
Exclusion criteria included moderate or severe pulmonary artery stenosis; reconstructive surgery on the pulmonary artery (PA) or pulmonary valve (PV) ; congenital anomalies of the PA or PV complicating ECHO determination of sPAP.
Initially, 295 women were considered for inclusion in the study, who were treated in the AICU of the PC with a prepartum sPAP ≥ 35 mmHg. After applying inclusion and exclusion criteria, 264 patients were selected for analysis. Four patients were corresponding the criteria for Group 3 PH (PH associated with lung pathology and/or hypoxia), 18 patients for Group 4 (PH due to pulmonary artery obstruction), and no patients were identified for Group 5. The majority of women (242) had PH classified as either Group 1 or Group 2. Among these, 142 had PH corresponding to Group 1 criteria, and 100 had PH corresponding to Group 2. The causes of pulmonary arterial hypertension (PH Group 1) and pulmonary venous hypertension (PH Group 2) in pregnant women are presented in table 1 and table 2.
| Pulmonary Arterial Hypertension Group 1 | n | % |
|---|---|---|
| Idiopathic pulmonary arterial hypertension | 14 | 9,9 |
| PAH caused by congenital heart diseases | 122 | 85,9 |
| PAH caused by connective tissue diseases | 5 | 3,5 |
| PAH caused by HIV | 1 | 0,7 |
| Number of patients | 142 | 100 |
| Pulmonary Venous Hypertension Group 2 | n | % |
|---|---|---|
| PH caused by heart failure with reduiced enjection fraction | 31 | 31 |
| Valvular heart disease | 57 | 57 |
| Congenital/acquired cardiovascular conditions leading to post-capillary PH | 12 | 12 |
| Number of patients | 100 | 100 |
Anesthetic management and intensive care provided during the postpartum period were according to the most current international and national guidelines available at the time of the patient’s admission [2, 3, 7, 8].
We identified seven variables as prenatal risk factors for the adverse course of the perinatal period:
- the patient’s age at the time of delivery;
- the functional class (FC) of heart failure (as classified by New York Heart Association (NYHA)) or pulmonary hypertension at the time of delivery;
- the need for intensive care during the antenatal period (before delivery);
- the left ventricular ejection fraction (LVEF) at the time of delivery;
- the systolic pulmonary artery pressure (sPAP), as determined by echocardiography, at its highest point during the prenatal period;
- the contractility of the right ventricle, as measured by the Tricuspid Annular Plane Systolic Excursion (TAPSE) at the time of delivery;
- the arterial blood oxygen saturation measured by pulse oximetry (SpO2) at the time of delivery.
The following five parameters were investigated as criteria for adverse maternal peripartum outcomes: 1) maternal mortality within 30 days postpartum; 2) preterm delivery, defined as delivery at less than 37 weeks of gestation; 3) decompensation of heart failure, manifested as the need for vasopressor and/or inotropic support at 48 hours postpartum; 4) worsening hypoxemia, manifested as the need for oxygen inhalation and/or a decrease in SpO2 at 48 hours postpartum compared to pre-delivery levels; 5) prolonged intensive care (IC), defined as the need for intensive care in the intensive care unit (ICU) during the postpartum period for more than 48 hours.
Statistical analysis was performed using Statistica 7.0 (StatSoft Inc., USA) and MedCalc 22.026 (MedCalc Software Ltd, Belgium). The total sample size met the requirements for logistic regression, adhering to the rule of at least 50 observations + 8 × m, where m represents the number of independent variables [9]. Normality of distribution was checked using the Kolmogorov–Smirnov and Shapiro–Wilk tests. Multivariable logistic regression analysis was performed to determine the odds ratio (OR), 95% confidence interval (CI), and statistical significance (p-value) to identify the influence of independent risk factors (predictors) on the binary outcome, which was the occurrence of adverse events in peripartum period (predictand). To determine the significance and critical value of the influence of these factors, ROC- curve analysis was conducted, calculating the area under the curve (AUC) and statistical significance (p-value). Model quality was classified as excellent when AUC was 0.9–1.0, very good when AUC was 0.8–0.9, good when AUC was 0.7–0.8, and moderate when AUC was 0.6–0.7. The threshold value (TV) of each variable was determined using the Youden’s J statistic (defined as the value that maximizes the sum of sensitivity and specificity); the sensitivity and specificity of the identified threshold value were also calculated.
Qualitative variables were compared using Fisher’s exact test. Quantitative variables were compared using Student’s t-test in the case of a normal distribution and the Mann—Whitney U-test for non-normally distributed data. Data are presented as mean ± standard deviation (M ± SD) for normally distributed data and as median and interquartile range (Me (Q1; Q3)) for non-normally distributed data. A critical significance level of p = 0.05 was used.
Results
Initially we analyzed the baseline characteristics (recorded prior to delivery) of the patients included in the study (table 3). This initial analysis confirmed a marked difference between patients with pulmonary hypertension (PH) in Groups 1 and 2.
| Parameter | PH Group 1 | PH Group 2 | р |
|---|---|---|---|
| Number of patients, n ( %) | 142 (58,7 %) | 100 (41,3 %) | |
| Age, years | 29 ± 6.3 | 32 ± 6.4 | 0.002 |
| Functional class | 2 (1; 2) | 2 (2; 2.5) | 0.03 |
| Antenatal intensive care in the ICU, n ( %) | 38 (26,8) | 36 (36) | 0.08 |
| LVEF, % | 61 (59; 65) | 57 (39; 64) | < 0.001 |
| sPAP, mmHg | 55.5 (45; 93) | 50 (45; 55) | 0.009 |
| TAPSE, cm | 1.7 (1.7; 2.1) | 1.7 (1.7; 2.3) | 0.5 |
| SрO2, % | 97 (95; 98) | 97 (97; 98) | 0.002 |
| Gestational age at delivery, weeks | 37 (34;39) | 37 (34;38) | 0.06 |
Characteristics of the clinical course of the peripartum period in patients with coexisting Pulmonary Arterial Hypertension (PH, Group 1)
In the second stage of our study, we conducted a detailed analysis cases involved peripartum management of patients with coexisting pulmonary arterial hypertension. Logistic regression analysis of the total sample of 242 patients with high PAP revealed that the presence of PAH (Group 1) is an independent risk factor for three out of five selected indicators of adverse peripartum outcomes (table 4).
| Characteristics of unfavorable peripartum period | OR | 95% CI | р |
|---|---|---|---|
| Maternal mortality | 5.91 | 0.73–48.03 | 0.042 |
| Preterm delivery | — | — | 0.477 |
| Heart Failure Decompensation | 3.48 | 1.27–9.54 | 0.008 |
| Postpartum Hypoxemia Deterioration | 10.12 | 3.86–26.53 | < 0.001 |
| Prolonged ICU managment | — | — | 0.839 |
To identify predictors of adverse outcomes during the peripartum period in patients with coexisting PAH Group 1, we conducted a logistic multivariate regression analysis within this group consisted of 142 patients (table 5).
Of the seven pre-delivery indicators assessed, five were found to be predictive of at least one adverse peripartum outcome. In patients with PAH Group 1, age and pre-delivery left ventricular ejection fraction (LVEF) were not associated with adverse outcomes.
| Indicators of the unfavorable perinatal period | Logistic regression parameters | |||
|---|---|---|---|---|
| Risk factors | OR | 95% CI | р | |
| Maternal mortality | SрO2 | 0.8187 | 0.7248–0.9247 | 0.0013 |
| Preterm delivery | sPAP | 1.0415 | 1.0212–1.0623 | 0.0001 |
| SрO2 | 0.6970 | 0.5264–0.9230 | 0.0118 | |
| Heart Failure Decompensation | sPAP | 1,0285 | 1.0092–1.0481 | 0.0036 |
| FC | 3.2127 | 1.3496–7.6476 | 0.0084 | |
| Postpartum Hypoxemia Deterioration | IC pre-delivery | 15.5895 | 1.1035–220.2289 | 0.0421 |
| sPAP | 1.1999 | 1.0838–1.3285 | 0.0004 | |
| TAPSE | 0.0072 | 0.0001–0.5402 | 0.0251 | |
| SрO2 | 0.6976 | 0.5560–0.8753 | 0.0019 | |
| Prolonged ICU managment | IC pre-delivery | 9.0714 | 2.5200–32.6550 | 0.0007 |
| sPAP | 1.0970 | 1.0632–1.1318 | < 0.0001 | |
The ROC — curve analysis validated the potential of 5 out of the 7 selected prenatal indicators as predictors of adverse peripartum outcomes in patients with coexisting pulmonary arterial hypertension Group 1 (table 6).
| Indicators of the unfavorable perinatal period | Risk factors | AUC | Sens, % | Spec, % | Cut -off | р |
|---|---|---|---|---|---|---|
| Maternal mortality | SрO2 | 0.872 | 75 | 97.83 | 80 | 0.0003 |
| Preterm delivery | sPAP | 0.862 | 77.78 | 84.81 | 62 | < 0.0001 |
| SрO2 | 0.823 | 65.08 | 89.87 | 96 | < 0.0001 | |
| Heart Failure Decompensation | sPAP | 0.872 | 100 | 72.5 | 72 | < 0.0001 |
| FC | 0.833 | 63.64 | 87.50 | 2 | < 0.0001 | |
| Postpartum Hypoxemia Deterioration | IC pre-delivery | 0.690 | 51.02 | 86.96 | 0 | 0.0001 |
| sPAP | 0.965 | 89.80 | 92.39 | 73 | < 0.0001 | |
| TAPSE | 0.624 | 34.69 | 90.22 | 1,6 | 0.0153 | |
| SрO2 | 0.856 | 75.51 | 88.04 | 96 | < 0.0001 | |
| Prolonged ICU managment | IC pre-delivery | 0.693 | 47.62 | 91.03 | 0 | < 0.0001 |
| sPAP | 0.910 | 79.37 | 94.87 | 72 | < 0.0001 |
Fig. 1.
The
ROC curve analysis evaluating relationship between the probability of prolonged
intensive care in the postpartum period and systolic pulmonary arterial
pressure during the prenatal period in patients with Group 1 pulmonary
hypertension
sPAP — систолическое давление
в легочной артерии в дородовый период; AUC — площадь под кривой.
Note: cut-off is in the frame.
Fig. 2.
The
ROC curve analysis evaluating relationship between the probability of hypoxemia deterioration in the postpartum period and sPAP during the prenatal period in patients with Group 1 PH
sPAP —systolic pulmonary arterial pressure
during the prenatal period; AUC —area under the ROC curve.
Note: cut-off is in the frame.
Fig. 3.
The
ROC curve analysis evaluating the relationship between the probability of heart
failure decompensation in the postpartum period and sPAP during the prenatal period in patients with Group 1 PH
AUC —area
under the ROC curve; sPAP —systolic pulmonary arterial
pressure during the prenatal period.
Note: cut-off is in the frame.
Characteristics of the clinical course of the peripartum period in patients with coexisting Pulmonary Venous Hypertension (PH Group 2)
In the third stage of our study, we investigated 100 cases of peripartum management of patients with coexisting pulmonary venous hypertension (PH Group 2). Logistic regression analysis of the entire cohort of 242 patients with pulmonary hypertension revealed that, unlike Group 1 PAH, PH Group 2 did not demonstrate predictive properties for adverse peripartum outcomes and was not a risk factor for any of the five indicators of such a complicated course.
It should be noted that the postpartum period did not always proceed safely in patients with concomitant PH Group 2. Thus, 46 women (46 %) required prolonged (more than 48 hours) monitoring and treatment in the AICU. To identify predictors of adverse peripartum outcomes, we performed a multivariable logistic regression analysis in this group of 100 women (table 7). Since there were no deaths among patients with coexisting PH Group 2, the number of indicators of adverse peripartum outcomes decreased from 5 to 4. Unexpectedly, prenatal LVEF demonstrated predictive ability for only one indicator of adverse outcomes – postpartum heart failure decompensation.
| Indicators of the unfavorable perinatal period | Logistic regression parameters | |||
|---|---|---|---|---|
| Risk factors | OR | 95% CI | р | |
| Preterm delivery | Age | 1.1081 | 1.0004–1.2274 | 0.0491 |
| IC pre-delivery | 8.9905 | 2.5902–31.2064 | 0.0005 | |
| sPAP | 1.1181 | 1.0618–1.1772 | < 0.0001 | |
| SрO2 | 0.4958 | 0.2907–0.8455 | 0.0100 | |
| Heart Failure Decompensation | LVEF | 0.8701 | 0.7590–0.9975 | 0.0460 |
| FC | 5.8888 | 1.2401–27.9647 | 0.0257 | |
| Postpartum Hypoxemia Deterioration | FC | 4.7784 | 1.3573–16.8229 | 0.0149 |
| Prolonged ICU managment | IC pre-delivery | 4.6226 | 1.6372–13.0518 | 0.0038 |
| SрO2 | 0.5324 | 0.3272–0.8662 | 0.0111 | |
| FC | 2.7590 | 1.4175–5.3700 | 0.0028 | |
The ROC - curve analysis confirmed the potential use of 5 out of 7 antenatal indicators as predictors of adverse outcomes during the peripartum period in patients with coexisting PHV group 2. Age and TAPSE prior to delivery did not demonstrate predictive significance (table 8).
| Indicators of the unfavorable perinatal period | Risk factor | AUC | Sens, % | Spec, % | Cut-off | р |
|---|---|---|---|---|---|---|
| Preterm delivery | IC pre-delivery | 0.707 | 57.14 | 84.31 | 0 | 0.0001 |
| sPAP | 0.786 | 67.35 | 82.35 | 54 | < 0.0001 | |
| SрO2 | 0.680 | 69.39 | 60.78 | 97 | 0.0008 | |
| Heart Failure Decompensation | LVEF | 0.919 | 100 | 86.32 | 30 | < 0.0001 |
| FC | 0.846 | 80 | 77.89 | 2 | 0.0002 | |
| Postpartum Hypoxemia Deterioration | FC | 0.766 | 40.00 | 97.89 | 3 | 0.0214 |
| Prolonged ICU managment | IC pre-delivery | 0.710 | 58.70 | 83.33 | 0 | 0.0001 |
| SрO2 | 0.664 | 95.65 | 27.78 | 98 | 0.0022 | |
| FC | 0.703 | 39.13 | 87.04 | 2 | 0.0001 |
Fig. 7.
The
ROC curve analysis evaluating the relationship between the probability of heart
failure decompensation in the postpartum period and left ventricular ejection fraction during the prenatal period in patients with Group 2 PH
AUC —
area under the ROC curve; LVEF — left ventricular ejection fraction.
Notes: cut-off is in the frame.
The clinical course of the peripartum period showed notable differences between patients in PH group 1 and PH group 2, particularly during the postpartum phase (see table 9). All cases of maternal mortality were associated with PH group 1. The duration of postpartum intensive care did not differ statistically between the two groups, likely due to the higher incidence of clinically significant cardiac arrhythmias that required intensive therapy and monitoring in patients from PH group 2.
| Indicator | PH Group 1, n = 142 | PH Group 2, n = 100 | р |
|---|---|---|---|
| Maternal mortality | 4 (2.8 %) | 0 | 0.12 |
| Preterm delivery | 63 (44.4 %) | 49 (49 %) | 0.28 |
| Heart Failure Decompensation | 22 (15.5 %) | 5 (5 %) | 0.008 |
| Postpartum Hypoxemia Deterioration | 49 (34.5 %) | 5 (5 %) | < 0.001 |
| Arrhythmias | 7 (4.9 %) | 15 (15 %) | 0.007 |
| Prolonged intensive care in ICU | 63 (44.4 %) | 46 (46 %) | 0.45 |
| Increase in sPAP postpartum | 17 (12 %) | 5 (5 %) | 0.049 |
| Decrease in sPAP postpartum | 40 (28.2 %) | 42 (42 %) | 0.02 |
Advanced Anesthetic Management and Intensive Care Strategies in the Peripartum Period for Women with Pulmonary Arterial and Pulmonary Venous Hypertension
The hallmark of hemodynamic disorders in pulmonary hypertension, the high risk of their occurrence during surgical abdominal delivery and the risk of hypoperfusion for mother and fetus dictate the need to find technologies to enhance safety in such situations. The main specific monitoring techniques, pharmacological methods and mechanical circulatory support strategies adjusted to the hemodynamic conditions of pulmonary hypertension, which we employed in patients with associated pulmonary hypertension, are outlined in table 10.
| Methods of anesthetic management | Group 1 PAH, n = 142 | Group 2 PVH, n = 100 | р |
|---|---|---|---|
| Nitric oxide inhalation | 48 (33.8 %) | 0 | < 0.001 |
| Continuous monitoring of CVP and arterial BP | 88 (62 %) | 93 (93 %) | < 0.001 |
| Continuous monitoring of PAP (Swan-Ganz catheter and pre-pulmonary termodilution) | 11(7.7 %) | 2 (2 %) | 0.079 |
| Transpulmonary thermodilution | 5 (3,5 %) | 2 (2 %) | 0.389 |
| «ECMO stand-by» technology | 15 (10.6 %) | 8 (8 %) | 0.331 |
| CS with preparediness for cardiac by-pass and cardiac surgery | 0 | 5 (5 %) | 0.011 |
Discussion
The analysis of literature data regarding maternal outcomes in patients with PH reveals a significant variability in results. Maternal mortality, for instance, ranges from 0 % to 37.1 % [11–17]. This substantial discrepancy is attributed not only to heterogeneity among study populations (various groups of PH were included in the research, differing initial severity of patients' conditions, levels of functional class, and adherence to therapy both before and during pregnancy), but also to the capabilities and experience of clinical centers in managing such patients. More recent studies generally report lower maternal mortality rates than earlier ones. In this regard, it is difficult to compare our results with the literature data. In a similar study by Y. Liu et al., maternal mortality was reported to be 5.5 % [12], whereas in our research, it stands at 1.7 %. It is important that the highest mortality rate is observed in Group 1 PH, as indicated by both our data and international studies. In the investigation by K. Sliwa et al., mortality among pregnant women with Group 1 PH was 10.3 %, whereas it was only 2.7 % in patients with associated Group 2 PH [13].
A similar trend was noted in the later study by Y. Liu et al., where mortality within one week post-delivery for patients with Group 1 PH was 5.4 %, while no fatal outcomes were reported for women with Group 2 PH [12]. In our 13-year study of 242 patients with associated pulmonary hypertension Groups 1 and 2, we observed 4 cases (1.7 %) of maternal mortality. All deaths were in Group 1 PH in patients with uncorrected heart defects complicated by Eisenmenger syndrome. The mortality rate among patients with associated PH Group 1 was 2.8 % (4 cases out of 142 pregnant women). In three cases, the fatal outcome was associated with heart failure and progressive critical hypoxemia, while in one case, it was due to massive pulmonary embolism in the early postpartum/postoperative period.
Pulmonary arterial hypertension (PAH) represents the most severe category among patients with pulmonary hypertension (PH), not only due to the high maternal mortality rate. In the study by Y. Liu et al., the incidence of heart failure in Group 1 PH was reported at 15.9 %, compared to 13.8 % in Group 2 PH, although this trend did not reach statistical significance. In the research conducted by Ch. Lv et al., heart failure complicated the postpartum period in 66.7 % of patients with idiopathic pulmonary arterial hypertension (a variant of PAH), while only 19 % of women with Group 2 PH experienced similar complications. In our study, decompensation of heart failure was also more frequent among patients with Group 1 PH, occurring in 15.5 % of cases, compared to 5 % in women with Group 2 PH (p = 0.008). The observed differences can be linked to the pathophysiological features of pulmonary arterial hypertension (PAH) during pregnancy. Specifically, there is a significant decline in the production of endogenous vasodilators after placental removal, followed by an increase in pulmonary artery pressure in the postpartum period. These changes result in heightened afterload on the right ventricle and the development of right ventricular heart failure [10]. In contrast, delivery had a beneficial effect on venous PH by gradually reduction in circulating blood volume, decreasing preload on the compromised left chambers and facilitating their function. These mechanisms are supported by statistical data — an increase in pulmonary artery pressure is more characteristic for Group 1 PH during the postpartum period, while a decrease is observed in Group 2 PH. The identification of risk factors for maternal mortality is limited by the low incidence of fatal outcomes and the difficulties associated with statistical analysis. In our study, significant risk factors corresponding to adverse outcomes during the peripartum period varied among different groups. In Group 1 PH, the most significant predictors were sPAP and SpO2, whereas in Group 2 PH, the primary risk factor was the severity of antenatal heart failure. Notably, the risk factors for premature delivery in both groups included increased sPAP and decreased SрO2. In clinical practice this combination indicated an increase in the right ventricular post-load with exacerbating right-to-left shunting for Group 1 PH. Conversely, for Group 2 PH, this combination was more likely presented with a clinical picture of cardiogenic pulmonary edema.
Literature data confirm the influence of elevated sPAP on the development of heart failure, particularly in patients with pulmonary hypertension in pregnancy. According to a meta-analysis by R. Ma et al., maternal outcomes, including mortality and complications related to the cardiovascular system, were statistically significantly more common in the group comprising moderate and severe pulmonary hypertension (sPAP over 50 mmHg) compared to the group with mild pulmonary hypertension (sPAP less than or equal to 50 mmHg), p < 0.00001 [15]. In a study by M. Yang et al., analyzing the postnatal course in 156 patients with PH, high sPAP was identified as a risk factor for heart failure during the peripartum period with an odds ratio (OR) of 1.045 and a 95 % confidence interval (CI) of 1.021 to 1.069 [16]. Similar results were obtained in our research. Elevated sPAP is a risk factor for heart failure decompensation with an OR of 1.03 and a 95 % CI of 1.01 to 1.05. The quality of the model based on ROC analysis is very good, with an area under the curve (AUC) of 0.872, sensitivity of 100 %, specificity of 72.5 %, and a threshold value of 72 mmHg. It is noteworthy that in our study, sPAP demonstrated predictive capability for 4 out of 5 indicators of adverse outcomes during the peripartum period. The threshold value of sPAP for these 4 indicators ranged from 62 to 73 mmHg. This statistically confirmed fact has important methodological implications. The systolic pulmonary artery pressure (sPAP) characterizes PH as “severe’’ during the prenatal period remains undefined. Our findings suggest that this threshold for prenatal sPAP can be considered as 70 mmHg.
The influence of functional class (FC) on adverse outcomes during the peripartum period is also supported by literature data. For instance, in the study by Y. Liu et al., it was noted that in 19 out of 20 cases of maternal mortality, the patients had a high FC [12]. In the study by W. Chen et al., FC III - IV is identified as a risk factor for maternal mortality, preterm delivery, and heart failure [17], which corresponds to the results we obtained.
It is important to note that to date, clinical guidelines for managing pregnant women with coexisting PH provide limited information on the specifics of anesthetic management. The approaches we employed are in line with the methodological recommendations from the Federation of Anesthesiologists and Reanimatologist regarding the perioperative management of patients with chronic heart failure (CHF), as well as those addressing the perioperative care of patients with coexisting heart valve pathology.
The "ECMO on standby" method was proposed by our group to reduce the risk of fatal outcomes in case of severe hemodynamic disorders in patients with pulmonary hypertension [18]. This technology involves preliminary catheterization of the femoral vein and artery with 16 G catheters, allowing for their rapid replacement with ECMO cannulas at the beginning of cardiopulmonary resuscitation. In this method, the ECMO device is in the operating room and ready for operating from the moment the patient begins to prepare for cesarean section. The use of the methods presented in Table 10 was empirical, decisions were made based on experience, taking into account objective assessments of the cardiovascular system's status.
The information obtained in this study on the risks of an adverse course of the peripartum period may help to objectify the use of the methods listed in table 10, some of which are quite invasive and associated with complications. Thus, invasive monitoring of blood pressure and central venous pressure (CVP) in patients with pulmonary hypertension of group 1 can be abandoned if functional class (FC) is less than 2, whether the systolic pulmonary artery pressure (sPAP) does not exceed 60 mmHg, and if oxygen saturation (SpO2) before delivery is above 96 %. In patients with PH of group 2, invasive monitoring of blood pressure and CVP can be avoided if the FC is less than 2. The use of extracorporeal membrane oxygenation (ECMO) standby technology is likely not indicated for women with coexisting PH of group 1 with sPAP less than 70 mmHg. Additional arguments for using this technology include an increase in FC of more than 2 and a decrease in SpO2 in the prenatal period to less than 96 % (factors associated with an unfavorable course during the perioperative period, as demonstrated in this study).
For patients with PH in group 2, the decision to use "ECMO standby" technology can be considered in cases where left ventricular ejection fraction (LVEF) is less than 30 %. The risk factor identified in this study, an FC more than 2, increases the need for the use of this technology.
Certainly, our aforementioned suggestions regarding the criteria for utilizing specific monitoring and treatment methods, derived from the analysis of identified risk factors, require validation through large clinical studies.
Conclusion
Pregnancy with coexisting pulmonary hypertension represents a heterogeneous group, characterized by variations in baseline disease severity, risk factors for adverse outcomes, and the clinical course during the postpartum period. In 91.7 % of cases, associated pulmonary hypertension in pregnant women is represented by Group 1 (pulmonary arterial hypertension, 53.8 %) and Group 2 (pulmonary hypertension related to left heart chamber pathology, or venous hypertension, 37.9 %).
Pregnancy with coexisting pulmonary arterial hypertension (PAH) is associated with more severe peripartum course compared to those with pulmonary venous hypertension (PVH). Initially, these patients demonstrate higher baseline systolic pulmonary artery pressure and lower oxygen saturation (SpO2). Adverse postpartum outcomes, including decompensated heart failure, elevated systolic pulmonary artery pressure, and reduced SpO2, occurred more frequently in PAH patients than in those with PVH. Mortality rates were 2.8 % in the PAH cohort, whereas no fatal outcomes were observed among PVH patients.
For patients with coexisting PAH, a significant risk factor for adverse outcomes during the peripartum period was the level of systolic pulmonary artery pressure prior to delivery. Its predictive capability was confirmed for 4 out of 5 markers of adverse outcomes. The threshold value for systolic pulmonary artery pressure was 70 mmHg. Additionally, the level of SрO2 prior to delivery was identified as a predictor of maternal mortality in cases of pulmonary arterial hypertension, with a threshold value of 80 %.
In women with associated pulmonary venous hypertension, a significant risk factor for adverse outcomes during the peripartum period was the functional class of heart failure prior to delivery. A factor associated with decompensation of heart failure postpartum was the left ventricular ejection fraction, with a threshold value of 30 %.
Disclosure. The authors (Pozhidaeva A.M., Zhuravleva M.S. and Bautin A.E.) are the authors of the Patent for the invention " Method of anaesthesia for caesarean section in pregnant women with Eisenmenger syndrome" RU 2823109 C1 dated July 18, 2024. Other authors declare no competing interests.
Author contribution. All authors according to the ICMJE criteria participated in the development of the concept of the article, obtaining and analyzing factual data, writing and editing the text of the article, checking and approving the text of the article.
Ethics approval. This study was approved by the local Ethical Committee of Almazov National Medical Research Centre (reference number: 06-23-13.06.2023).
Funding source. This study was not supported by any external sources of funding.
Data Availability Statement. The data supporting the conclusions of this study can be obtained from the corresponding author upon reasonable request.
