Hypertension And PET Flashcards
What is the primary change in the circulation during pregnancy?
Vasodilation
Fall in the systemic vascular resistance
When is the nadir of BP in pregnancy?
22-24/40
What should be taken as the diastolic reading?
Phase V (Disappearance)rather than phase IV (muffling) or Korotkoff sounds
How should BP be taken in pregnancy?
Sitting or lying on side with 30 degree tilt
If taken supine, it will be falsely low due to decreased venous return
If you use a normal size cuff to measure BP on a larger women, what error will occur?
Over-estimate of BP
What is the prevalence of Gest HTN?
10-15%
What is the prevalence of PET?
3-5%
What is the commonest cause of iatrogenic prematurity?
PET
What are secondary causes of hypertension?
How do you investigate for them?
Renal artery stenosis - listening for renal bruits, USS
Underlying renal disease - urinalysis, ? Proteinuria, haematuria, serum Creat
Aortic coarctation - radiofemoral delay, CT
Conn’s - hypokalaemia
Cushing’s
Phaechromocytoma - urinary catecholamines
Hyper parathyroid is - serum Ca
What are women with pre-existing HTN at risk of in pregnancy?
PET (25%)
PTB (28%)
LBW (17%)
How does PET affect the kidney?
Decreased GFR Proteinuria Rise in serum creat Rise in rate Oliguria
What is the cause of hyperuricaemia in PET?
Placental ischaemia
Accelerating trophoblast turnover and production of purines (substrate for xanthine oxidase)
What is the cause of hyponatraemia in PET?
What is the treatment?
Fluid overload
With an element of SIADH?
Rx: fluid restriction
What are crises / complications in pre-eclampsia?
HELLP Pulmonary oedema Renal failure Hepatic rupture DIC Placental abruption Cerebral haemorrhage Cortical blindness (linked to PRES) Transient LV dysfunction
What are the two stages in the pathogenesis of PET?
- Abnormal placentation
- spiral arteries do not undergo normal vascular remodelling, failing to become high capacitance, low resistance vessels
- invading placenta unable to optimise its blood supply
- uteroplacental ischaemia - Maternal response
- metabolic disturbance
- exaggerates inflammatory response
- higher levels of pro-inflammatory cytokines associated with endothelial dysfunction, which leads to platelet activation and vasoconstriction
- cause widespread micro vascular damage and dysfunction
What is the role of VEGF and TCF-beta1 in a normal pregnancy?
Maintain endothelial health
By interacting with endogenous endothelial receptors
What factors are secreted by the placenta in excess in PET?
Soluble Flt1 (sFlt1) and soluble endoglin (sEng)
- anti-angiogenic factors
- antagonise VEGF and TGF-B1 (transforming growth factor) signalling, and PIGF (placental growth factor)
- therefore producing systemic endothelial dysfunction
sFlt1 and sEng and increased and PIGF is decreased in the maternal circulation weeks before the onset of PET
What is notching in the uterine artery at 20-24/40 predictive of?
PET
FGR
Placental abruption
When is there a risk of cerebral auto regulation in PET?
MAP > 150
Mother at risk of cerebral haemorrhage
How do you calculate MAP?
D + 1/3 (S-D)
Women with PET should be encouraged to use what in labour?
Regional analgesia / anaesthesia
How should postpartum oliguria in PET be managed?
Safer to err not he side of volume depletion and mild AKI than to treat immediate postpartum oliguria with aggressive volume replacement and risk pulmonary oedema
What are the risks for future health, in women who have had PET?
Hypertension (3-4x)
IHD (2x)
Cerebrovascular disease
What is the risk of recurrent PET?
15%
Increases with earlier gestation
