Time Interval Between Maternal Electrocardiogram and Venous Doppler Waves in Normal Pregnancy and Preeclampsia: A Pilot Study

Zusammenfassung

Ziel: Beurteilung des Zeitintervalls zwischen maternem Elektrokardiogramm (EKG) und venösen Dopplerwellen zu verschiedenen Zeitpunkten bei unkomplizierten Schwangerschaften (UP) und bei Präeklampsie (PE). Material und Methoden: Querschnittsstudie bei 40 unkomplizierten Einlingsschwangerschaften, die in vier 10er-Gruppen entsprechend dem Gestationsalter eingeteilt wurden: 10.–14. Schwangerschaftswoche (SSW; UP 1), 18.–23. SSW (UP2), 28.–33. SSW (UP3) und ≥ 37. SSW (UP4). Zudem wurde ein fünfte Gruppe von zehn Frauen mit PE eingeschlossen. Die Untersuchung der Dopplerflüsse in den renalen interlobären Venen (RIV) und den hepatischen Venen (HV) wurde entsprechend standardisierter Kriterien zusammen mit einem maternalen EKG durchgeführt. Das Zeitintervall zwischen der P-Welle im EKG und der korrespondierenden A-Deflektion der venösen Dopplerwelle wurde bestimmt (PA) und ins Verhältnis zur Dauer des Herzzyklus (RR) gesetzt (PA/RR). Ergebnisse: In hepatischen Venen war PA/RR länger in UP 4 als in UP 1 (0,48 ± 0,15 versus 0,29 ± 0,09, p ≤ 0,001). Der Vergleich aller UP Gruppen zeigte einen graduellen PA/RR Anstieg mit zunehmendem Gestationsalter. Bei PE ist die HV PA/RR kürzer als in UP 3 (0,25 ± 0,09 versus 0,42 ± 0,14, p < 0,01); dieser Unterschied persistierte auch unter antihypertensiver Therapie (0,28 ± 0,06 versus 0,42 ± 0,14, p ≤ 0,01, n = 6). Ähnliche Ergebnisse ergaben sich bei beiden Nieren. In UP 1 aber nicht in UP 3 oder UP 4 war der HV PA/RR kürzer in der Leber als in der linken und rechten Niere (0,29 ± 0,09 versus 0,38 ± 0,12, p < 0,01, und versus 0,36 ± 0,09, p ≤ 0,01). Schlussfolgerung: PA/RR ist organspezifisch und gestationsabhängig und scheint in Bezug zum venösen Gefäßtonus und/oder dem intravaskulären Füllungszustand zu stehen. Erhöhte Werte mit zunehmendem Gestationsalter stimmen mit bekannten Parametern maternaler kardiovaskulärer Adaptation überein. Kürzere Werte bei PE sind vereinbar mit der kardiovaskulären Maladaptation. Unsere Pilotstudie eröffnet neue Forschungsmöglichkeiten hinsichtlich der Wertigkeit des Zeitintervalls zwischen maternalem EKG und venösen Dopplerwellen als neuer Parameter zur Untersuchung der kardiovaskulären (Patho-)Physiologie und des maternalen venösen Kompartiments während der Schwangerschaft mit der Duplexsonografie.

Abstract

Purpose: To evaluate the time interval between maternal electrocardiogram (ECG) and venous Doppler waves at different stages of uncomplicated pregnancy (UP) and in preeclampsia (PE). Materials and Methods: Cross-sectional pilot study in 40 uncomplicated singleton pregnancies, categorized in four groups of ten according to gestational age: 10 – 14 weeks (UP1), 18 – 23 weeks (UP2), 28 – 33 weeks (UP3) and ≥ 37 weeks (UP4) of gestation. A fifth group of ten women with PE was also included. A Doppler flow examination at the level of renal interlobar veins (RIV) and hepatic veins (HV) was performed according to a standard protocol, in association with a maternal ECG. The time interval between the ECG P-wave and the corresponding A-deflection of the venous Doppler waves was measured (PA), and expressed relative to the duration of the cardiac cycle (RR), and labeled PA/RR. Results: In hepatic veins, the PA/RR is longer in UP 4 than in UP 1 (0.48 ± 0.15 versus 0.29 ± 0.09, p ≤ 0.001). When all UP groups were compared, the PA/RR increased gradually with gestational age. In PE, the HV PA/RR is shorter than in UP 3 (0.25 ± 0.09 versus 0.42 ± 0.14, p < 0.01) and this difference persisted under anti-hypertensive treatment (0.28 ± 0.06 versus 0.42 ± 0.14, p ≤ 0.01, n = 6). Similar results were found in both kidneys. In UP 1 but not in UP 3 or UP 4, the HV PA/RR is shorter in the liver than in the left and right kidney (0.29 ± 0.09 versus 0.38 ± 0.12, p < 0.01, and versus 0.36 ± 0.09, p ≤ 0.01). Conclusion: The PA/RR is organ-specific and gestation-dependent, and is considered to relate to venous vascular tone and/or intravascular filling. Increased values at advanced gestational stages are consistent with known features of maternal cardiovascular adaptation. Shorter values in preeclampsia are consistent with maternal cardiovascular maladaptation mechanisms. Our pilot study invites more research of the relevance of the time interval between maternal ECG and venous Doppler waves as a new parameter for studying the gestational cardiovascular (patho)physiology of the maternal venous compartment by duplex sonography.

Key words

veins - electrocardiography (ECG) - ultrasound Doppler - pregnancy

References

• 1 Gyselaers W. Hemodynamics of the maternal venous compartment: a new area to explore in obstetric ultrasound imaging.  Ultrasound Obstet Gynecol. 2008;  32 716-717
• 2 Karabulut N, Baki Y A, Karabulut A. Renal vein Doppler ultrasound of maternal kidneys in normal second and third trimester pregnancy.  Br J Radiol. 2003;  76 444-447
• 3 Gyselaers W, Verswijvel G, Molenberghs G et al. Interlobar venous flow is different between left and right kidney in uncomplicated third trimester pregnancy.  Gynecol Obstet Invest. 2008;  65 6-11
• 4 Gyselaers W, Molenberghs G, Mesens T et al. Maternal hepatic vein Doppler velocimetry during uncomplicated pregnancy and pre-eclampsia.  Ultrasound Med Biol. 2009;  35 1278-1283
• 5 Roobottom C A, Hunter J D, Weston M J et al. Hepatic venous Doppler waveforms: changes in pregnancy.  J Clin Ultrasound. 1995;  23 477-482
• 6 Gyselaers W, Molenberghs G, Van Mieghem W et al. Doppler measurement of renal interlobar vein impedance index in uncomplicated and preeclamptic pregnancies.  Hypertens Pregnancy. 2009;  28 23-33
• 7 Gyselaers W, Mesens T, Tomsin K et al. Maternal renal interlobar vein impedance index is higher in early- than in late-onset preeclampsia.  Ultrasound Obstet Gynecol. 2010;  36 69-75
• 8 Gyselaers W, Mesens T. Renal interlobar vein impedance index: A potential new Doppler parameter in the prediction of preeclampsia?.  J Matern Fetal Neonatal Med. 2009;  22 1219-1221
• 9 Pedersen J F, Dakhil A Z, Jensen D B et al. Abnormal hepatic vein Doppler waveform in patients without liver disease.  Br J Radiol. 2005;  78 242-244
• 10 Appleton C P, Hatle L K, Popp R L. Superior vena cava and hepatic vein Doppler echocardiography in healthy adults.  J Am Coll Cardiol. 1987;  10 1032-1039
• 11 Ommen S R, Nishimura R A, Hurrell D G et al. Assessment of right atrial pressure with 2-dimensional and Doppler echocardiography: a simultaneous catheterization and echocardiographic study.  Mayo Clin Proc. 2000;  75 24-29
• 12 Martin N, Lilly L S. The cardiac cycle: Mechanisms of heart sounds and murmurs. In: Lilly L S, (ed.) Pathophysiology of heart disease.. Philadelphia: Lippincott: Williams & Wilkins; 2007: 29-44
• 13 Ommen S R, Nishimura R A, Appleton C P et al. Clinical utility of Doppler echocardiography and tissue Doppler imaging in the estimation of left ventricular filling pressures: A comparative simultaneous Doppler-catheterization study.  Circulation. 2000;  102 1788-1794
• 14 Lederer J W. Cardiac electrophysiology and the electrocardiogram. In: Boron W F, Boulpaep E L, (eds.) Medical physiology.. Philadelphia: Saunders Elsevier Science; 2003: 483-507
• 15 Haendl T, Strobel D, Steinebrunner N et al. Hepatic transit time in benign liver lesions.  Ultraschall in Med. 2008;  29 184-189
• 16 Davey D A, MacGillivray I. The classification and definition of the hypertensive disorders of pregnancy.  Am J Obstet Gynecol. 1988;  158 892-898
• 17 Duvekot J J, Peeters L L. Maternal cardiovascular hemodynamic adaptation to pregnancy.  Obstet Gynecol Surv. 1994;  49 S1-S14
• 18 Laenen A, Vangeneugden T, Geys H et al. Generalized reliability estimation using repeated measurements.  Br J Math Stat Psychol. 2006;  59 113-131
• 19 Verbeke G, Molenberghs G. Linear mixed models for longitudinal data. Springer; 2001
• 20 Galderisi M, Cattaneo F, Mondillo S. Doppler echocardiography and myocardial dyssynchrony: a practical update of old and new ultrasound technologies.  Cardiovasc Ultrasound. 2007;  5 28
• 21 Allen J, Murray A. Age-related changes in peripheral pulse timing characteristics at the ears, fingers and toes.  J Hum Hypertens. 2002;  16 711-717
• 22 Sharwood-Smith G, Bruce J, Drummond G. Assessment of pulse transit time to indicate cardiovascular changes during obstetric spinal anaesthesia.  Br J Anaesth. 2006;  96 100-105
• 23 Berzigotti A, Castaldini N, Rossi V et al. Age dependency of regional impedance indices regardless of clinical stage in patients with cirrhosis of the liver.  Ultraschall in Med. 2009;  30 277-285
• 24 Sakai K, Imaizumi T, Maeda H et al. Venous distensibility during pregnancy. Comparisons between normal pregnancy and preeclampsia.  Hypertension. 1994;  24 461-466
• 25 Schneider A R, Teuber G, Kriener S et al. Noninvasive assessment of liver steatosis, fibrosis and inflammation in chronic hepatitis C virus infection.  Liver Int. 2005;  25 1150-1155
• 26 Satyapal K S, Rambiritch V, Pillai G. Additional renal veins: incidence and morphometry.  Clin Anat. 1995;  8 51-55
• 27 Satyapal K S. Classification of the drainage patterns of the renal veins.  J Anat. 1995;  186 (Pt 2) 329-333
• 28 Satyapal K S, Rambiritch V, Pillai G. Morphometric analysis of the renal veins.  Anat Rec. 1995;  241 268-272
• 29 Hays P M, Cruikshank D P, Dunn L J. Plasma volume determination in normal and preeclamptic pregnancies.  Am J Obstet Gynecol. 1985;  151 958-966
• 30 Khalil A A, Cooper D J, Harrington K F. Pulse wave analysis: a preliminary study of a novel technique for the prediction of pre-eclampsia.  BJOG. 2009;  116 268-276
• 31 Spaanderman M E, Willekes C, Hoeks A P et al. The effect of pregnancy on the compliance of large arteries and veins in healthy parous control subjects and women with a history of preeclampsia.  Am J Obstet Gynecol. 2000;  183 1278-1286
• 32 Hon E H, Fukushima T. R-pulse wave timing in cardiovascular monitoring: further observations.  Obstet Gynecol. 1992;  79 597-600