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| Year : 2021 | Volume
: 32
| Issue : 1 | Page : 170-173 |
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| Central Systolic and Diastolic Blood Pressure Pressures during Hemodialysis |
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Jafar Al-Said1, Corazon Suyao2
1 Department of Nephrology, Internal Medicine, Bahrain Specialist Hospital, Manama, Bahrain
2 Department of Outpatient, Bahrain Specialist Hospital, Manama, Bahrain
Click here for correspondence address and email
| Date of Web Publication | 16-Jun-2021 |
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 Abstract | | |
Maintaining fixed dry weight and controlling cardiovascular risk factors during hemodialysis (HD) requires well-controlled blood pressure (BP) with regular measurements. Keeping the BP stable during HD is challenging in some patients with end-stage renal disease (ESRD). Accurate measurement of BP is the key, as it helps prevent intradialytic hypotension. It is still unclear if there is a difference between using the central or peripheral BP measurements in ESRD. To study if there is a significant difference between the central and peripheral BP, we tested the central and peripheral BP in 14 ESRD patients during their HD session. We compared 326 peripheral BP readings with 326 central BP measurements. There was a significant difference noticed with a lower central systolic and pulse pressure and a higher central diastolic and mean arterial pressure as compared with the peripheral pressure readings. Since BP measurement is the major factor to determine target organ hypoperfusion during HD, measuring the central pressure measurements during HD could help mitigating the risk of inducing unnoticed target organ hypoperfusion during HD.
How to cite this article:
Al-Said J, Suyao C. Central Systolic and Diastolic Blood Pressure Pressures during Hemodialysis. Saudi J Kidney Dis Transpl 2021;32:170-3 |
How to cite this URL:
Al-Said J, Suyao C. Central Systolic and Diastolic Blood Pressure Pressures during Hemodialysis. Saudi J Kidney Dis Transpl [serial online] 2021 [cited 2021 Jul 31];32:170-3. Available from: https://www.sjkdt.org/text.asp?2021/32/1/170/318519 |
| Introduction | |  |
Hypotension is one of the common complications during hemodialysis (HD), specifically among end-stage renal disease (ESRD) who recently started renal replacement therapy or those who are hemodynamic unstable. Maintaining a stable blood pressure (BP) and preventing hypotension is challenging among these patients.[1],[2],[3],[4] Accurate BP measurement is the key factor to avoid and prevent intra-dialytic hypotension, which is defined as a drop in systolic BP of 20 mm Hg.[1] We usually rely on measuring the peripheral BP, via the brachial or tibial arteries, to determine the target BP and define the cut off for hypotension.
Studies have shown that central aortic pressure is more accurate in predicting target organ damage. It was observed that central aortic pressure holds a stronger correlation with other cardiovascular (CV) risk factors.[5],[6] The difference between the central and peripheral BP measurement among ESRD is not studied extensively. We wanted by this study to identify the difference between the central and the peripheral BP measurements during HD.
| Methodology | | |
This study is a prospective, non-interventional study among adult ESRD patients receiving regular HD. The patients selected were those who are on regular HD in our unit, hemodynamically stable, using regular medications and on fixed dialysis orders. Patients who were hemodynamically unstable, having acute kidney injury or had recent medication or dialysis order adjustments, were excluded. The research was approved by the local research committee. Consents were obtained from the patients to measure their BP via a Mobil-O-Graph with a peripheral cuff and computer analyzer software for the data. The demographic factors were recorded via electronic files. Central and peripheral BP were repeatedly measured every 30 min during two to three full HD sessions for each patient. The validity of the automated non-invasive central pressure measurement was proven in multiple studies.[7],[8]
Paired t-test, using the Statistical Package for the Social Sciences version 18.0 software (SPSS Inc., Chicago, IL, USA, was utilized to test the significant difference between the central and the peripheral BP readings for the systolic, diastolic, pulse pressure, and the mean arterial pressures (MAP). P<0.01 was required to reject the null hypothesis.
| Results | | |
The number of patients included was 14 ESRD patients on regular HD. During 33 HD sessions, 326 peripheral and 326 central BP measurements were recorded. The mean age was 62.6 years (SD12.9), males were 40%. All the patients had hypertension. Thirteen patients were diabetic. Five patients had IHD and 22% of the whole readings were obtained from patients who underwent either PTCA, percutaneous coronary angioplasty or coronary artery bypass graft. The mean systolic, diastolic, pulse pressure and MAP are shown in [Table 1]. As noted, there was a significant statistical difference with lower central systolic and pulse pressures, but higher central diastolic and MAP as compared to peripheral measurement. | Table 1: Mean systolic, diastolic, pulse pressure, and mean arterial pressure for the central as well as the peripheral blood pressure readings, with the range of difference and the mean difference between central and peripheral readings.
Click here to view |
| Discussion | | |
In healthy adults, the central BP was proven to be different from the peripheral measurement. With aging and increased atherosclerosis, the stiff vessels will lose their elastic recoil. This will be manifested in a higher central systolic pressure and lower central diastolic pressure as compared with the peripheral pressure measurements.[9] Studies among CKD patients have shown that the elasticity of the large arteries starts to decline during the early stages of renal impairment. As compared to other patients with normal kidney function, CKD patients have more profuse vascular calcifications with ridged vessels.[9]. Due to the loss of the vascular elastic recoil, the pulse wave velocity will increase. The peripheral systolic BP will be higher, but the diastolic BP will be lower as compared to the central measurement.[9] This phenomenon happens normally with aging, but it is more pronounced among ESRD patients.[10],[11],[12],[13]
Our aim of this research was to know whether the central BP measurements are different from the peripheral measurements during the HD with the vascular hemodynamic alterations, and to consider the central measurement in our decision regarding the target BP during HD. When we measure only the peripheral BP and try to challenge the patient’s BP to get to his/her dry weight, we might be causing the unnoticed drop in the central pressure that could lead eventually to target organ damage. There was no earlier study that tested the difference between the central and peripheral BP during HD.
This study proves that there was a significant difference between the central and peripheral BP measurements among ESRD patients during the whole HD session. As elaborated in the result section in [Table 1], the central systolic and pulse pressure were significantly lower than the peripheral readings. On the other hand, the central diastolic and MAP were significantly higher than the peripheral BP. This difference was more pronounced among patients with higher CV risk factors. This raises the possibility that during HD treatment monitoring only the peripheral BP, will not be enough to identify and prevent decreased central systolic pressure and target organ perfusion.
In fact, we have noticed in a couple of patients during their regular HD sessions that they had overt hypotensive symptoms, including; nausea, vomiting, cramps, and abdominal pain but their peripheral BP was around 140/90 mm Hg. All their electrolytes were within normal limits. Upon measuring their central aortic pressures, we found that there was a 30 mm Hg difference between the central and peripheral systolic pressure. When we kept this in mind during successive HD sessions and increased the cutoff limit for ultrafiltration, their symptoms completely resolved. In fact, this observation had triggered the current research work.
It is true to say that until today the kidney is the only organ that can be replaced by a machine in patients with ESRD, and the patient can still have a fare quality of life. However, with all the development and progress, HD still carries very high unacceptable mortality rates. Could the unnoticed lower central pressure be the reason behind the poor outcome in HD? Are we inducing central hypoperfusion injury while trying to achieve what is known as the dry weight? These questions will need further studies. Further studies are required to translate these findings into solid clinical outcomes. Could the high mortality in dialysis be altered by monitoring the central aortic pressure measurements during each HD session? Future research will be required to clarify that aspect.
| Conclusion | | |
When comparing the central and peripheral BP measurements during HD, there was a significantly lower central systolic and pulse with a higher central diastolic and MAP. During HD, measuring only the peripheral BP might not be enough to identify hypotension and prevent target organ damage. Adding noninvasive central pressure measurement could reduce the possibility of the target organ.
| Acknowledgment | | |
The authors would like to thank all dialysis team at Bahrain Specialist Hospital.
Conflict of interest: None declared.
| References | | |
| 1. | Sulowicz W, Radziszewski A. Pathogenesis and treatment of dialysis hypotension. Kidney Int 2006;70:36-9.  |
| 2. | Henrich WL, Flythe JE. Intradialytic Hypotension in an Otherwise Stable Patient. Available from: contents/intradialytic-hypotension-in-an-otherwise-stable-patient. |
| 3. | Sands JJ, Usvyat LA, Sullivan T, et al. Intradialytic hypotension: Frequency, sources of variation and correlation with clinical outcome. Hemodial Int 2014;18:415-22. |
| 4. | Reilly RF. Attending rounds: A patient with intradialytic hypotension. Clin J Am Soc Nephrol 2014;9:798-803. |
| 5. | Grassi G. Central blood pressure – A novel cardiovascular risk marker. E JESS 2009;7:22. |
| 6. | McEniery CM, Cockcroft JR, Roman MJ, Franklin SS, Wilkinson IB. Central blood pressure: Current evidence and clinical importance. Eur Heart J 2014;35:1719-25. |
| 7. | Papaioannou TG, Karageorgopoulou TD, Sergentanis TN, et al. Accuracy of commercial devices and methods for noninvasive estimation of aortic systolic blood pressure a systematic review and meta-analysis of invasive validation studies. J Hypertens 2016; 34:1237-48. |
| 8. | Natarajan K, Cheng HM, Liu J, et al. Central blood pressure monitoring via a standard automatic arm cuff. Sci Rep 2017;7:14441. |
| 9. | Mizobuchi M, Towler D, Slatopolsky E. Vascular calcification: The killer of patients with chronic kidney disease. J Am Soc Nephrol 2009;20:1453-64. |
| 10. | Briet M, Bozec E, Laurent S, et al. Arterial stiffness and enlargement in mild-to-moderate chronic kidney disease. Kidney Int 2006;69:350-7. |
| 11. | Safar ME, Blacher J, Pannier B, et al. Central pulse pressure and mortality in end-stage renal disease. Hypertension 2002;39:735-8. |
| 12. | London GM, Blacher J, Pannier B, Guérin AP, Marchais SJ, Safar ME. Arterial wave reflections and survival in end-stage renal failure. Hypertension 2001;38:434-8. |
| 13. | Briet M, Boutouyrie P, Laurent S, London GM. Arterial stiffness and pulse pressure in CKD and ESRD. Kidney Int 2012;82:388-400. |
Correspondence Address:
Jafar Al-Said
Department of Nephrology and Internal Medicine, Bahrain Specialist Hospital, Manama
Bahrain
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DOI: 10.4103/1319-2442.318519 PMID: 34145127 
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