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Saudi Journal of Kidney Diseases and Transplantation
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ORIGINAL ARTICLE Table of Contents   
Year : 2007  |  Volume : 18  |  Issue : 3  |  Page : 355-360
Optimizing Hypertension Control in Hemodialysis Patients: A Proposed Management Strategy


Department of Nephrology and Dialysis, Ibn Rochd University Hospital Center, 20100 Casablanca, Morocco

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   Abstract 

Objective: The purpose of the study was to assess the efficiency of a goal-oriented therapeutic strategy in lowering blood pressure and reducing the need for antihypertensive medications in 168 patients undergoing long-term hemodialysis. Methods: Patients were managed initially by achieving optimal dry weight. After reduction of the dry weight, patients with uncontrolled arterial hypertension were dialyzed using a 1.25 mmol/L calcium concentration buffer. Results: The predialysis mean arterial blood pressure (PDBP) was 127.4/74.2 mmHg for the total population. Fifty (29.76%) of the total study population were hypertensive. Of them, 88% (44 patients) were receiving antihypertensive drugs, while the others were not on such medications. Twenty patients (40% of the hypertensives) were receiving one antihypertensive drug, 17 (34%) were receiving two antihypertensive drugs, while 7 patients (14%) were receiving three or more drugs. There was a significant increase in the number of patients with good control of PDBP in the second data collection [45 patients (90%)] compared to the first data collection of 40 patients (80%). Similarly, there was a significant reduction in the number of patients with uncontrolled PDBP in the second data collection (5 patients (10%) compared to the first data collection of 10 patients (20%). The average blood pressure in the first data collection was 137.2/76.3 and 167.4/87.1 mmHg in the controlled and uncontrolled blood pressure groups respectively. In the second data collection, the average blood pressure was 136.4/75.1 and 161.6/86.3 mmHg in the controlled and uncontrolled groups respectively. Conclusion: Therapeutic approach using combination of dry weight reduction and dialysis with low calcium dialysate provides acceptable long-term results in patients with arterial hypertension and reduces the need for antihypertensive medication.

Keywords: End-stage renal disease, Hemodialysis, Hypertension, Therapy

How to cite this article:
Tarrass F, Addou K, Benjelloun M, Zamd M, Medkouri G, Hachim K, Benghanem MG, Ramdani B. Optimizing Hypertension Control in Hemodialysis Patients: A Proposed Management Strategy. Saudi J Kidney Dis Transpl 2007;18:355-60

How to cite this URL:
Tarrass F, Addou K, Benjelloun M, Zamd M, Medkouri G, Hachim K, Benghanem MG, Ramdani B. Optimizing Hypertension Control in Hemodialysis Patients: A Proposed Management Strategy. Saudi J Kidney Dis Transpl [serial online] 2007 [cited 2020 Jul 3];18:355-60. Available from: http://www.sjkdt.org/text.asp?2007/18/3/355/33751

   Introduction Top


Hypertension is an established risk factor for mortality and morbidity in the general population, due to increased rate of ischemic heart disease. [1],[2] Hypertension is present in 70 to 90% [3],[4] of patients on hemodialysis (HD) and constitutes one of the major risk factors contributing to cardiovascular disease in these patients. Several factors, with or without antihypertensive drugs, are used to achieve proper blood pressure control; these include reduction of salt intake, lowering dialysate sodium concentration, and appropriate ultrafiltration. [5],[6] The aim of this study is to assess the efficacy of a goal­oriented strategy based on dry weight reduction and dialysis with low calcium buffer in lowering blood pressure and reducing the need for antihypertensive medications in patients undergoing long-term HD.


   Patients and Methods Top


Patients

Patients with stage-5 renal failure who have been on maintenance HD for at least six months were selected (168 patients-89 males, 79 females; mean age: 44.6 ± 20.8 years). All patients received their dialysis treatment three times per week, four hours per session. Polysulfone dialyzers and bicarbonate bath with dialysate sodium concentration of 140 mmol/L and calcium concentration of 1.75 mmol/L were used for conventional dialysis.

Vascular access was in the form of dualcath (Hemotech, France) catheters in 4 patients (3%), native arteriovenous fistula in 152 (90%), and arteriovenous graft in 12 patients (7%). Blood flow rate was 250-300 ml/min or more, and dialysate flow rate was 500 ml/min. Patients having predialysis blood pressure of more than 140/80 mmHg, with or without edema, and those who required antihypertensive medication to control blood pressure were identified as hypertensives. Optimal predialysis blood pressure was defined as BP less than 140/90 mm Hg, as recommended by the UK Renal Registry, [7] and the goal was to lower blood pressure levels to 130/80 mmHg, as recommended by K/DOQI guidelines. [8] Exclusion criteria included acutely ill patients, vascular access dysfunction, and non-adherence to thrice­weekly dialysis.

Blood pressure measurement

Mercury column sphygmomanometer was used for BP recording, which was done by a trained clinician. All recordings were obtained with the patient in the sitting position using the phase 5 as the diastolic pressure, and a mean of two repeated measurements was taken for documenttation. Patients were well acquainted with the recording procedure, as it is a routine protocol in the unit prior to each dialysis.

Therapeutic protocol

Phase 1: Reduction of the dry weight

The dry weight and the methods for achievement of the same were tailored for each patient. In patients with fluid overload, the end-dialysis target weight was reduced by 1 kg at each treatment until edema disappeared or predialysis blood pressure dropped to <140/80. Cramps and/or dizziness that occurred were treated at the adjustment phase. Patients were educated about the adjustment phase and dry weight. The use of antihypertensive medications to reduce blood pressure was discouraged. Dose reduction or discontinuation of any medication was carried out after consulting the nephro­logist. Advice for daily fluid and salt intake was taken whenever it was necessary. All patients were instructed to reduce their salt intake to less than 2g/day. In patients without fluid overload, reduction of dry weight was gradual and was achieved at a rate of 0.5 to 7.5 kg each treatment to avoid hypertension. Patients and nurses were educated about the importance of gradual reduction of dry weight to avoid intolerable hypotension. In patients who were receiving antihypertensive medications, once blood pressure began to fall, the dose of anti­hypertensive medication was reduced gradually.

Phase 2: Dialysis with a low-calcium concentration bath

After achieving the target dry weight, patients with uncontrolled hypertension were dialyzed using a 1.25 mmol/L calcium concentration buffer, in order to control blood pressure and to reduce the need for antihypertensive medications.


   Results Top


The study population

The demographics, dialysis duration, ranges of blood pressure, and reported causes of ESRD in the total study population, as well as in the hypertensive and normotensive groups, are shown in [Table - 1]. The predialysis mean BP was 127.4/74.2 mmHg for the total population. A total of 50 patients (29.76%) among the total study population were hypertensive. Of them, 44 patients (88%) were receiving antihypertensive drugs, while the remaining patients were not. Twenty patients (40% of the hypertensives) were receiving one antihypertensive drug, 17 (34%) were receiving two antihypertensive drugs, while 7 patients (14%) were receiving three or more drugs.

Blood pressure control

There was a significant increase in the number of patients with PDBP control in the second data collection (45 patients (90%) compared to the first data collection (40 patients (80%). Similarly, there was a significant reduction in the number of patients with uncontrolled PDBP in the second data collection (5 patients (10%) compared to the first data collection (10 patients (20%). The average blood pressure in the first data collection was 137.2/76.3 and 167.4/87 mmHg in the controlled and uncontrolled blood pressure groups respectively. In the second data collection, the average blood pressure was 136.4/75.1 and 161.6/86.3 mmHg in the controlled and uncontrolled groups respectively. In 5 patients (10%), we were unable to control the BP after the two protocol phases. After a detailed evaluation, we found that renovascular hypertension secondary to atherosclerotic renal artery stenosis was the cause of treatment resistance in one case; while in the remaining four cases, the cause of refractory hypertension could not be determined. Data of patients with uncontrolled BP at the end of the study are reported in [Table - 2].


   Discussion Top


The primary focus of management of hypertension in patients on HD should be to optimize intravascular volume status by progressive ultrafiltration until appropriate dry weight is achieved. The crucial role of achieving and maintaining patients at dry weight is illustrated by the Tassin experience. [9] By performing long and slow dialysis and meticulous ultrafiltration, this group has been able to achieve excellent blood pressure control and survival rates in its patients. However, the patient's popu­lation and dialysis techniques used in this center may be different from most other centers; while clearly documenting the importance of blood pressure control, the extrapolation of these data to other centers is limited. In our group, appropriate reduction of dry weight permitted control of hyperten­sion in 80% of the population.

Calcium ions play a pivotal role in the contractile process of both vascular smooth muscle cells and cardiac myocytes. The effect of dialysate calcium concentration on blood pressure seems to be mediated predominantly through changes in myocardial contractility, although several investigators also found a change in vascular reactivity. [11],[12],[13] A recent study reported a significantly larger decline in blood pressure during dialysis with low dialysate calcium concentration, compared with high dialysate calcium concentration, in patients with normal cardiac function. This was attributed to decrease in left ventricular contractility with the use of low calcium dialysate. [14] In another study in cardiac-compromised patients, the effects of low-calcium and high-calcium dialysate on systolic blood pressure course were compared. [15] Systolic blood pressure decreased to a statistically and clinically significant degree during ultrafiltration with the use of low-calcium dialysate. Our study protocol resulted in lowering of the blood pressure in five patients (50% of patients with uncontrolled BP, after the first phase).

In five patients (10%), we were unable to control the BP with the measures adopted. The reasons underlying the poor control of blood pressure in this population are not well defined; excessive interdialytic weight gain, poor compliance to dialysis and medication regimens, and under-prescription of antihypertensive drugs are some possible factors. [10]

In patients with refractory hypertension, initial efforts should focus on limiting inter-dialytic weight gain and optimizing the dialysis regimen so that adequate ultrafiltration is performed and optimal dry weight is achieved. In patients who are poorly compliant, supervised administration of atenolol three times a week may be a safe and effective technique for lowering blood pressure. [16] Patients who remain refractory or have suggestive signs/symptoms should be evaluated for secondary hypertension. [17]

In conclusion, our results suggest that the primary goal in the treatment of hypertension should be to attain appropriate dry weight and maintain volume control through limiting salt and fluid intake and ultrafiltration of excess fluids. If this approach is unsuccessful, dialysis with low­ calcium buffer is available to help control blood pressure and reduce the need for antihypertensive medications in patients with ESRD.

 
   References Top

1.Sytkowski PA, D'Agostino RB, Belanger AI, Kannel WE. Secular trends in long term sustained hypertension, long-term treatment, and cardiovascular mortality: The Framingham 1950-1990. Circulation 1996;93:697-703.  Back to cited text no. 1    
2.Burt VL, Whelton P, Roccella EJ, et al. Prevalence of hypertension in the US adult population: Results from the Third National Health and Nutrition Examination survey, 1988-1991. Hypertension 1995;25:305-13.  Back to cited text no. 2  [PUBMED]  [FULLTEXT]
3.Raine A, Margreiter R, Brunner FP, et al. Report on management of renal failure in Europe, XXII, 1991. Nephrol Dial Transplant 1992;2:S7-35.  Back to cited text no. 3    
4.Salem MM. Hypertension in hemodialysis population: A survey of 649 patients. Am J Kidney Dis 1995; 26: 461-8.  Back to cited text no. 4  [PUBMED]  
5.Ozkahya M, Ok E, Cirit M, et al. Regression of left ventricular hypertrophy in haemodialysis patients by ultrafiltration and reduced salt intake without antihyper­tensive drugs. Nephrol Dial Transplant 1998;13:1489-93.  Back to cited text no. 5  [PUBMED]  [FULLTEXT]
6.Krautzig S, Janssen U, Koch KM, Granolleras C, Shaldon S. Dietary salt restriction and reduction of dialysate sodium to control hypertension in maintenance haemodialysis patients. Nephrol Dial Transplant 1998;13:552­3.  Back to cited text no. 6  [PUBMED]  [FULLTEXT]
7.Feehally J, Goldsmith D, Ansell D, et al. Chapter 11: Factors that may influence cardiovascular disease - Blood pressure and serum cholesterol. In: The UK Renal Registry Report 2003.2003;1-28.  Back to cited text no. 7    
8.National Kidney Foundation. K/DOQI clinical practice guidelines on hypertension and antihypertensive agents in chronic kidney disease. Am J Kidney Dis 2004;43 (S1):11-3.  Back to cited text no. 8    
9.Charra B, Calemard E, Ruffet M, et al. Survival as an index of adequacy dialysis. Kidney Int 1992;41:1286-91.  Back to cited text no. 9  [PUBMED]  
10.Rahman M, Dixit A, Donley V, et al. Factors associated with inadequate blood pressure control in hypertensive hemodialysis patients. Am J Kidney Dis 1999;33: 498-506.  Back to cited text no. 10  [PUBMED]  
11.Fellner SK, Lang RM, Neumann A, Spencer KT, Bushinsky DA, Borow KM. Physiological mechanism for calcium­induced changes in systemic arterial pressure in stable dialysis patients. Hyper­tension 1989;13:213-8.  Back to cited text no. 11    
12.Leunissen KM, van den Berg BW, van Hooff JP. Ionized calcium plays a pivotal role in controlling blood pressure during haemodialysis. Blood Purif 1989;7:233-9  Back to cited text no. 12  [PUBMED]  
13.Henrich WL, Hunt JM, Nixon JV. Increased ionized calcium and left ventricular contractility during haemodialysis. N Engl J Med 1984;310:19-23.  Back to cited text no. 13  [PUBMED]  
14.Van Kuijk WH, Mulder AW, Peels CH, Harff GH, Leunissen KM. Influence of changes in ionized calcium on cardio­vascular reactivity during haemodialysis. Clin Nephrol 1997;47:190-6.  Back to cited text no. 14    
15.Van der Sande FM, Cheriex EC, van Kuijk WH, Leunissen KM. Effect of dialysate calcium concentrations on intra-dialytic blood pressure course in cardiac-compromised patients. Am J Kidney Dis 1998;32:125-31.  Back to cited text no. 15  [PUBMED]  
16.Agrawal R. Supervised atenolol therapy in the management of hemodialysis hypertension. Kidney Int 1999;55:1528-35.  Back to cited text no. 16    
17.Saldanha LF, Weiler EW, Gonick HC. Effect of continous ambulatory peritoneal dialysis on blood pressure control. Am J Kidney Dis 1993;21:184-8.  Back to cited text no. 17  [PUBMED]  

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Correspondence Address:
Faissal Tarrass
Salama 3, Gr 6, "B", N° 21 20450 Casablanca
Morocco
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PMID: 17679745

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    Tables

  [Table - 1], [Table - 2]

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