Echo Changes in Hypertensive Disorder of Pregnancy.

AIM: Acute preeclampsia is associated with significantly higher prevalence of asymptomatic global left ventricular (LV) abnormal function and myocardial injury than uneventful pregnancy. Hence, this study was undertaken to evaluate the LV changes in preeclamptic women and to compare with normotensive women.
MATERIALS AND METHODS: This study was conducted in the Department of Obstetrics and Gynaecology, M. S. Ramaiah Medical College and Teaching Hospital, Bengaluru. Two-hundred women were in each group: 200 patients with preeclampsia as cases and 200 normotensive patients as controls.
RESULTS: The mean LV end-systolic volume (LV ESV) in preeclamptic women was 33.45 ± 2.8, LV end-diastolic volume (LV EDV) was 106 ± 3.01, and LV systolic mass (LV Ms) was 87.1 ± 1.65 when compared to normotensive women LV ESV - 27 ± 0.74, (P < 0.0001) LV EDV - 106.2 ± 0.43, (P - 0.3528), and LV Ms - 84 ± 0.56 (P < 0.0001).
CONCLUSION: This study emphasizes the importance of identifying this subset of preeclamptic patients with echo changes who are at higher risk of developing cardiovascular complications later in life by undergoing echocardiography.

INTRODUCTION

Preeclampsia is an acute increase in blood pressure during pregnancy, which is short-lived. More than 50% of the women with elevated blood pressure during pregnancy return to normal by 6 weeks. Nearly every one in four mothers with preeclampsia/eclampsia is at risk of persistent hypertension after the puerperium.[1] Acute preeclampsia is associated with significantly higher prevalence of asymptomatic global left ventricular (LV) abnormal function/geometry and myocardial injury than uneventful pregnancy.[2] Cross-sectional studies of women with preeclampsia have revealed diverse hemodynamic findings such as elevated cardiac output (CO), high vascular resistance, and reduced CO and myocardial contractility.[3] Impairment of LV diastolic function as well as systolic function appear very early in the course of heart disease.[4] Detection of any abnormality in the LV diastolic function and its treatment at an asymptomatic phase can help in improving the prognosis. There are not many studies on myocardial function in preeclamptic women. Hence, this study was undertaken to evaluate the LV changes in preeclamptic women and to compare with normotensive women.

MATERIALS AND METHODS

This study was conducted in the Department of Obstetrics and Gynecology, M. S. Ramaiah Medical College, Bengaluru. A case–control type of study was done which included 200 women in each group - 200 patients with preeclampsia as cases and 200 normotensive patients as controls. Preeclampsia is defined as new-onset hypertension of 140/90 mmHg or more and 24 h proteinuria of 0.3 g or more, occurring after 20 weeks of gestation.[56] Blood pressure was checked with a mercury sphygmomanometers using an appropriate size cuff with the woman lying in semi-reclining or sitting position with arm at the level of the heart and phase V Korotkoff sound (sound disappearance) to measure diastolic blood pressure. Echocardiography was performed, and data regarding LV function were recorded with patients in left lateral position.

The criteria for exclusion were gestational age <20 weeks of gestation, preexisting medical disorders such as hypertension, diabetes mellitus, heart disease, and renal disease, and connective tissue disorders. A P < 0.05 was considered statistically significant.

RESULTS

A majority of the patients in both hypertensive and normotensive patients were in the age group 21–30 years. Body mass index was normal in 60 women (30%) of preeclamptic women and in 168 women (84%) of normotensives while 108 women (54%), 32 (16%) of preeclamptic women were overweight and obese, respectively, in comparison to the normotensives in which only 28 women (14%) were overweight and none were obese [Table 1].

Table 1

Distribution of patients according to age, gestational age and BMI

	Preeclampsia	Percentage	Normotensive	Percentage
Age (years)
<20	20	10	16	8
21-30	125	62.5	116	58
31-40	55	27.5	68	34
Gestation age (in weeks)
≤20	32	16.00	28	14
21-30	102	51.00	100	50.00
31-40	66	33.00	72	36.00
BMI
≤18.5	0	0.00	4	2.00
18.5-24.9	60	30.00	168	84.00
25-29.9	108	54.00	28	14.00
≥30	32	16.00	0	0.00

BMI = Body mass index

Out of the 200 women with preeclampsia, the mean systolic pressure was 161.4 mmHg ± 10.4 and mean diastolic blood pressure was 110.3 mmHg ± 7.6 and among the 200 normotensive women the mean systolic pressure was 105 mmHg ± 8.2 and mean diastolic blood pressure was 73.5 mmHg ± 7.1. CO in the preeclamptic group was 64.2 ± 3.4 ml/min as compared to 56.99 ± 0.78 ml/min in normotensive group. This observation was statistically significant at P < 0.0001. The mean LV end-systolic volume (LV ESV) in preeclamptic women was 33.45 ± 2.8, LV end-diastolic volume (LV EDV) was 106 ± 3.01, and LV systolic mass (LV Ms) was 87.1 ± 1.65 when compared to normotensive women LV ESV - 27 ± 0.74, (P < 0.0001) LV EDV - 106.2 ± 0.43, (P - 0.3528), and LV Ms - 84 ± 0.56 (P < 0.0001) [Table 2].

Table 2

Systolic echocardiography

	CO	LV ESV	LV EDV	LV MS	LV MD
Preeclampsia
n	200	200	200	200	200
Mean	64.2	33.45	106	87.1	125
SD	3.4	2.8	3.01	1.65	6.5
Normotensive
n	200	200	200	200	200
Mean	56.99	27	106.2	84	109.2
SD	0.78	0.74	0.43	0.56	4.98
P	<0.0001	<0.0001	0.3528	<0.0001	<0.0001

SD = Standard deviation, LV EDV = Left ventricular end-diastolic volume, LV ESV = Left ventricular end-systolic volume, LV MS = Left ventricular systolic mass, CO = Cardiac output, LV MD = Left ventricular diastolic mass

Table 3 shows comparison of diastolic parameters between normotensive and preeclamptic subjects. Mean isovolumetric relaxation time (IVRT) in preeclamptic women was 98 ± 9.99, E-wave deceleration time mean was 162 ± 18.99, mean peak E-wave velocity as 0.98 ± 0.14, A-wave - 0.70 ± 0.12, ratio of E/A - 1.4 ± 0.24 while that of normotensives IVRT - 84.6 ± 0.59, E-wave deceleration time mean 128.2 ± 5.1, mean peak E-wave velocity as 0.66 ± 0.09, A-wave - 0.56 ± 0.03, ratio of E/A - 1.20 ± 0.24.

Table 3

Diastolic echocardiography

	IVRT	Edec	E	A	E/A
Preeclampsia
n	200	200	200	200	200
Mean	98	162	0.98	0.70	1.4
SD	9.99	18.99	0.14	0.12	0.24
Normotensive
n	200	200	200	200	200
Mean	84.6	128.2	0.66	0.56	1.20
SD	0.59	5.1	0.09	0.03	0.24
P	<0.0001	<0.0001	<0.0001	<0.0001	<0.0001

SD = Standard deviation, Edec = E-wave deceleration time, IVRT = Isovolumetric relaxation time

DISCUSSION

Preeclampsia is a disease unique to pregnancy that contributes substantially to maternal and fetal morbidity and mortality, and the condition has been thought to be one of hypoperfusion in which increased vascular resistance characterizes the associated hypertension.[7] Arterial hypertension produces evident structural changes in the left ventricle usually accompanied by functional alterations and in the great majority of cases, these alterations precede the appearance of clinical manifestations.[8] In this study, we have evaluated the role of echocardiography in preeclampsia and found that there were marked LV changes in these patients. In normal pregnancy, an increased preload and a decreased afterload favor an improved emptying of the left ventricle during systole and a reduction of the end-systolic pressure.[9] In preeclamptic women, the elevated afterload is linked with a reduced emptying of the left ventricle and elevated end-systolic pressure. In our study, we found that the mean LV ESV in normotensive women was 27 ± 0.74 while in preeclamptic women 33.45 ± 2.8 (P < 0.0001).

The prolonged IVRT in hypertensive patients in comparison to normotensives (98 ± 9.99, 84.6 ± 0.59) was significant (P < 0.0001) as LV pressure takes greater time to fall below the atrial pressure compared with normotensive patients as also shown in study by Valensise et al. in which IVRT in normotensives was 71.1 ± 5.0 ms (at 33 ± 1 weeks), P < 0.001.[10] The mean E-wave deceleration time in preeclamptic subjects was 162 ± 18.99 compared to 128.2 ± 5.1 in normotensive women which indicates that passive filling of left ventricle is increased during early diastole. The mean E-wave velocity in preeclamptic subjects was 0.98 ± 0.14 compared to normotensive women in whom it was 0.66 ± 0.09 (P < 0.0001), which indicates that the pressure gradient across the mitral valve during early passive filling was higher. This was comparable to the study by Solanki and Maitra in which the preeclamptic patients had E-wave velocity was 1.023 ± 0.1926 in comparison to the normotensives 0.675 ± 0.137.[3] The mean peak A-wave velocity in preeclamptic patients was 0.70 ± 0.12 in comparison to the normotensives (0.56 ± 0.03, P < 0.0001) which reveals the significance of atrial systole.

CONCLUSION

Preeclampsia still contributes to a majority of maternal mortality and morbidity. This study shows that there are significant cardiovascular dynamics changes in subjects with preeclampsia which can be studied by echo. Hence, this study emphasizes the importance of identifying this subset of preeclamptic patients who are at higher risk of developing cardiovascular complications later in life by undergoing a timely echocardiography.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.