Is preeclampsia associated with a higher risk for ischemic stroke or hemorrhagic stroke?

Preeclampsia is Associated with a Higher Risk of Hemorrhagic Stroke Than Ischemic Stroke

Preeclampsia is more strongly associated with hemorrhagic stroke than ischemic stroke, with hemorrhagic stroke showing a higher relative risk in the postpartum period (RR 28) compared to ischemic stroke (RR 8.7). 1

Epidemiology and Risk Association

Stroke during pregnancy is a relatively rare but potentially devastating event, with an overall incidence of 34.2 per 100,000 deliveries. The specific rates are:

• Ischemic stroke: 11 per 100,000 deliveries
• Hemorrhagic stroke: 9 per 100,000 deliveries 1

However, the risk distribution changes dramatically in the postpartum period:

• Postpartum ischemic stroke: 8.7-fold increased risk
• Postpartum hemorrhagic stroke: 28-fold increased risk 1

Preeclampsia/eclampsia is present in approximately 25-45% of pregnancy-associated stroke cases, making it one of the most significant risk factors 1.

Pathophysiological Mechanisms

The relationship between preeclampsia and stroke types can be understood through several key mechanisms:

1. Hemorrhagic Stroke Mechanism: Preeclampsia-associated hemorrhagic stroke is primarily driven by:

   • Severe disturbance in cerebral autoregulation 1
   • Severe systolic hypertension (≥160 mmHg) 2
   • Endothelial dysfunction 1, 3

2. Ischemic Stroke Mechanism: Preeclampsia-associated ischemic stroke is primarily related to:

   • Endotheliopathy 1
   • Thrombophilia 1
   • Poor collateral flow 3

A critical finding from clinical studies is that systolic blood pressure appears to be the dominant factor in stroke risk. In one study of preeclampsia patients who suffered stroke, 95.8% had systolic pressures ≥160 mmHg before the stroke event, while only 12.5% had diastolic pressures ≥110 mmHg 2.

Long-term Cardiovascular Risk

Women with a history of preeclampsia face increased long-term cardiovascular risks:

• 75% increased risk of cardiovascular-related mortality 1
• Increased risk of coronary artery disease (OR 1.24,95% CI 1.08-1.43) 1
• Higher prevalence of coronary atherosclerosis (36.3% vs 28.3% in women without preeclampsia) 1
• Higher odds of non-fatal stroke 1

Clinical Implications and Management

For women with preeclampsia who develop neurological symptoms:

1. Immediate evaluation for any neurological symptoms, particularly severe headache (most common symptom) 4

2. Blood pressure management:

   • Initiate antihypertensive therapy when systolic blood pressure reaches or exceeds 155-160 mmHg 2
   • This represents a paradigm shift from the traditional focus on diastolic pressure 2

3. Thromboprophylaxis should be considered, especially in the postpartum period 4

4. Long-term monitoring for cardiovascular risk factors is essential, as preeclampsia serves as an early warning sign for future cardiovascular disease 5

Risk Stratification

Women at highest risk for stroke in the setting of preeclampsia include those with:

• Severe systolic hypertension (≥160 mmHg) 2
• Eclampsia 1
• HELLP syndrome (though this doesn't significantly alter blood pressures compared to non-HELLP preeclampsia) 2
• Postpartum status (highest risk period) 1

Prevention Strategies

Prevention of stroke in preeclamptic women should focus on:

1. Aggressive blood pressure control, particularly targeting systolic hypertension 2
2. Appropriate magnesium sulfate therapy for seizure prophylaxis, though this hasn't been shown to reduce stroke risk specifically 3
3. Close monitoring during the postpartum period, when risk is highest 1

The evidence clearly demonstrates that while both stroke types are associated with preeclampsia, the risk of hemorrhagic stroke is substantially higher, particularly in the postpartum period, and is primarily driven by severe systolic hypertension and impaired cerebral autoregulation.