Can High Hematocrit Cause Hypertension?

[MikeDaly1970]

Hi guys,

I know that I have high hematocrit, and I'm booked in for donation next Tuesday.

My question is, can high hematocrit cause hypertension, as my doc says I've now high blood pressure, he says my high hematocrit does not cause high blood pressure, but my research says different.

What do you guys think?

Thanks

 

[Blackhawk]

My personal experience, yes at 52-54% my systolic BP increases

 

[MikeDaly1970]

Thank you very much Blackhawk

Has anyone any good links to this so I can show my doctor, he denies Haemotcrit can raise diastolic blood pressure

 

[Nelson Vergel]

Yes, high hematocrit can cause hypertension. Hematocrit refers to the proportion of blood volume that is occupied by red blood cells. An elevated hematocrit level increases blood viscosity, which in turn can elevate blood pressure through several mechanisms.

Mechanisms Linking High Hematocrit to Hypertension

1. **Increased Blood Viscosity**:
- High hematocrit levels increase the viscosity of blood, which raises the resistance to blood flow. This increased resistance can lead to higher blood pressure as the heart must work harder to pump the thicker blood through the circulatory system[1][2][4][5][9].

2. **Peripheral Vascular Resistance**:
- Elevated hematocrit levels are associated with increased peripheral vascular resistance. This is partly due to the increased viscosity but also due to the reduced ability of blood vessels to dilate properly, which further contributes to higher blood pressure[1][3][5].

3. **Endothelial Function**:
- High hematocrit levels can impair endothelial function, reducing the production of nitric oxide, a vasodilator. This impairment can lead to vasoconstriction and increased blood pressure[10][13][15].

Evidence from Studies

- **General Population Studies**:
- Studies have shown a significant association between high hematocrit levels and the prevalence of hypertension. For instance, a study reported that a 10-unit increase in hematocrit (e.g., from 35% to 45%) is associated with an increase of 4-6 mm Hg in arterial pressure and a twofold increased risk of hypertension[1].

- **Polycythemia and Hypertension**:
- Polycythemia, a condition characterized by an increased number of red blood cells, is strongly associated with hypertension. Patients with polycythemia have a higher prevalence of hypertension compared to controls, even after adjusting for other risk factors[2][6][7][8][12][14].

- **Longitudinal Studies**:
- Longitudinal studies have demonstrated that men with higher hematocrit levels have an increased risk of developing hypertension over time. For example, a study found that men whose hematocrit increased over time had a 25% increased risk of developing hypertension compared to those whose hematocrit decreased[4][19].

Clinical Implications

- **Management of Hematocrit Levels**:
- Managing hematocrit levels can be crucial in controlling blood pressure, especially in conditions like polycythemia vera. Treatments such as phlebotomy, which reduces hematocrit levels, can help manage hypertension in these patients[12][14].

- **Risk Prediction**:
- Hematocrit levels can serve as a prognostic marker for hypertension, aiding in the early detection and management of high blood pressure in at-risk individuals[5].

In summary, high hematocrit levels are causally associated with hypertension through mechanisms involving increased blood viscosity, peripheral vascular resistance, and impaired endothelial function. This relationship is supported by various studies across different populations and conditions.

Citations:
[1] https://www.ahajournals.org/doi/pdf/10.1161/01.HYP.20.3.319
[2] Gaisböck syndrome (polycythemia and hypertension) revisited: results from the national inpatient sample database - PubMed
[3] Blood Pressure and Hematocrit in Diabetes and the Role of Endothelial Responses in the Variability of Blood Viscosity
[4] High blood hematocrit increases the risk of the incidence of hypertension in men
[5] Association of hematocrit with blood pressure and hypertension
[6] Gaisböck syndrome (polycythemia and hypertension)... : Journal of Hypertension
[7] Blood pressure profile, sympathetic nervous system activity, and subclinical target organ damage in patients with polycythemia vera - Polish Archives of Internal Medicine
[8] Polycythemia vera as a rare cause of hypertension in a young man
[9] Effect of hematocrit on blood pressure via hyperviscosity
[10] Managing High Blood Pressure: The Cardiologist’s Perspective | ASH Clinical News | American Society of Hematology
[11] Polycythaemia and hypertension caused by renal artery stenosis | Archives of Disease in Childhood
[12] Polycythemia Vera: What It Is, Symptoms & Treatment
[13] Hemoglobin and hematocrit levels are positively associated with blood pressure in children and adolescents 10 to 18 years old - Scientific Reports
[14] https://www.hopkinsmedicine.org/health/conditions-and-diseases/polycythemia-vera
[15] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2214674/
[16] https://www.cedars-sinai.org/health-library/diseases-and-conditions/p/polycythemia-vera.html
[17] https://journals.physiology.org/doi/10.1152/ajpheart.00496.2010
[18] https://www.ajconline.org/article/0002-9149(66)90430-9/abstract
[19] https://journals.lww.com/jhypertens...od_hematocrit_predicts_hypertension_in.9.aspx

 

[MikeDaly1970]

Wow thank you very much Nelson

Can I ask.a final question to ease my mind.

next week I'm having blood donation will.this bring my blood pressure back to so called normal, it's only gotten higher since haemotcrit got higher

 

[Nelson Vergel]

next week I'm having blood donation will.this bring my blood pressure back to so called normal, it's only gotten higher since haemotcrit got higher

How much is your hematocrit now and your blood pressure?