Hemodynamic Instability in HD patients: Dialysis Hypotension Prof Ali BAŞÇI MD FERA Ege University Medical School

Transcription

1 Hemodynamic Instability in HD patients: Dialysis Hypotension Prof Ali BAŞÇI MD FERA Ege University Medical School

2 Relationship between blood pressure and mortality in patients treated with volume control policy U-shape Ozkahya M, et al Nephrol Dial Transplant 2006 Patients with SBP between mmhg had lowest mortality rate The patients with hypotension had also high mortality 2

3 Hypertension is always due to hypervolemia in dialysis patients. The dialysis patient with dialysis hypotension (DH) or intradialytic hypotension(idht) doesn t mean that the patient is hypovolemic eventhough they might be hypervolemic most of the case. K/DOQI guidelines: a decrease in systolic blood pressure >=20 mmhg or a decrease in MAP by 10 mmhg associated with clinical events and need for nursing interventions. The reported incidence in cohort studies varies between 6 and 27% (Tisler A 2002). More recently published incident is 25% (KDOQI Working Group 2005) 3

4 Hypertension is always due to hypervolemia in dialysis patients. The dialysis patient with dialysis hypotension (DH) or intradialytic hypotension(idht) doesn t mean that the patient is hypovolemic eventhough they might be hypervolemic most of the case. In a recent analysis of HEMO Study Database frequency DH (defined an absolute intradialytic nadir SBP <90mmHg ) was 11.3 per 100 sessions and associated with an increased adjusted mortality rate over 2 years (OR % Cl ) (Flythe et al. JASN 2015) Most recent study (Ododu A 2016 JASN) found decreases in SBP 20 mmhg or MAP 10 mmhg occurred in 77.7 %, clinical symptoms occurred in 21.4 %, and nursing interventions were performed in 8.5 % of dialysis sessions in 3 month of 3815 HD sessions. 4

5 Consequences of dialysis hypotension Increased risk of cerebral, myocardial, mesenteric ischemic events Vascular access trombosis Acceleration of decline in residuel renal function Interferes with the attempts of dialysis team reaching and maintaining dry weight. It ultimately result in ECV fluid overload due to subobtimal HD sessions 5

6 Pathophysiology of DH o Main two factors Excesive salt intake/intradialytic weight gain Short dialysis duration. o Excesive UF o UF dynamics :refill fenomenon o Dialysis itself Dialyser Hemofitration or dialysis Dialysate o Buffer o Sodium concentration o Sodium modelling or UF modeling 6

7 Seabra VF, Jaber BL

8 Braam B, Dorhout Mess EJ 2011 Interdialytic salt intake is the key issue. The higher salt intake the higher excessive ECV fluid. Higher fluid exccess will make it exremely challenging to remove the aquired ECV expansion in relatively short amount of time 8

9 Koomans et al. KI 1994 The reduction in plasma volume with constant UF rate can differ greatly among the patents due to differenses in refill rate which vary from only 0.7% to as much as 21.9% (Koomans HA, Dorhout Mees EJ et al.hypertension 1982) Refill rate is related overhydration. Patient with little overhydrated patient showed much more decrease in BV as a result of insuffıcient refill. Changes in plasma volume after 2L of UF. The patient with largest decrease have the smallest ECV excess (Koomans et al. KI 1994 ) o The circulatory adaptation occurs in short time. Critical point in pathogenesis of IDH is decrease of plasma volume below a critical threshold resulting from an imbalance between UF and refill rate.

10 Brummelhuis W.I et al ASAIO 2008 Starling forces at the capillary level determine refill process. Oncotic pressure and hydrostatic pressure gradient still driving forces for water distrubution and determine refill rate. Water redistrubution may not be easy from intersitial space since ıt is very large area. For this reason even large amount of decrease in BV may not effect hydrostatic pressure in intersitisium. Refill is start after a while. BV decrease is always overshoot. This overshoot will be proportional to rate of UF which determine fluid excess and UF time. 10

11 Katzarski KS 1997AJKD Changes in BV and IVCD in group of patients with 3h and 6h diaysis. Overshoot in BV is much more prominent in short dialysis 11

12 Dialysis Time and Frequency Dialysis time is also important. Availability of high permeable membranes makes possible to remove waste products. Frequency and duration of HD sessions are important for removing high amount of ECV excessive fluid. o When UF rate exceeds 35 ml/kg/hour. (2L /hour for 60kg person), acute BP drop can not be avoided. The best way to prevent IDH is increasing frequency and/or duration of HD sessions addional to reduce the UF rate by limiting IDWG. 12

13 Dialysis Time and Frequency UF rates above 10 ml/hour/kg are associated with higher risks of intradialytic hypotension (odds ratio 1.30; P=.045) and mortality (RR 1.09; P=.02)(Saran R DOPPS Groups 2006 KI) In the FHN Nocturnal Trial, the frequency of IDH episodes was 65% lower than in conventional HD (95% CI ; P <.001), possibly because of the markedly lower UF rate(kotanko P FHN Study Group 2015 Hemodial Int) The Tassin group, applying strict dietary salt restriction in addition to longer HD, reported a frequency of IDH episodes as low as 5.7%.(Charra B et al 2003 J. Nephrol) We reported that the frequency of IDH episodes decreased from 64 to 20 per 1000-HD sessions after 12 months of 8-hour (vs 4 hour) treatment (P <.001) in a case-controlled prospective study (Ok E. Et al 2011 NDT). 13

14 Post Dialysis BW should decrease gradualy In DRIP Study (Agarwal R et al Hypertension 2009) o RCT in conventional HD patients, post HD body weight reduced by 0.9kg at 4 weeks resulting in a change -6.9 and -33.1mmHg in SDP and DBP respectively, but IDH increased. The other RCT (Curatola et al J. Nephrol 2011) o a decrease of BP /81+9mmHg to /78+11 mmhg with reduction of body weight by intensive UF but they also faced an increase in IDH In contrast, Ege Group showed no increase in IDH during a gradual reduction of post-hd BW; decreased 22% to7% and 18% to 11% in two different studies( Özkahya et al J Nephrol 2011, Am J Kidney Dis 1999) o In these two studies is in conventional HD patient, like Tassin long HD group (Charra B et al J nephrol 2003) we stopped all antihypertensive Rx and reduced IDWG by strict dietary salt restriction. 14

15 Ok E et al NDT

16 Cardiac functions LEFT VENTRICULAR HYPERTROPHY one of the most important factor in tolarance volume changes. Presence of LVH o will make achievement and maintenance of dry weight more difficult o may indirectly contribute to continuing hypertension and further cardiac demage. 16

17 Braam B, Dorhout Mess EJ

18 Cardiac functions AUTONOMIC NERVOUS SYSTEM Many investigators have tried to identify disturbances of baroreseptor reflex function which may effect CV system. Autonomic impairment may explain why some patients are hypotensive prone. o But there is no conclusive evidence. Autonomic functions are diminished diabetic and elderly patients. 18

19 Cardiac functions Bezold-Jarisch Reflex: The role of the heart maintaing in circulation and BP in the face of decreasing BV relatively low. Low venous return result in insufficient filling of ventricule. Sudden collaps decrease in sympatic tonus, bradicardia happens decreases TPR and CO increases. Abolition of bradiacardia by atropin does not effect hypotension. 19

20 Cardiac Functions DIASTOLIC FUNCTIONS : Severe diastolic disfunction is associated with decreased tolarance for the volume changes. This is also related to LVH. Khouri SJ et al 2004 Am.J of Cardiol. E: Peak early diastolic transmitral flow velosity A Peak late diastolic transmitral flow velocity Parabolic curve shows opposite effect of preload and relaxation. In diastolic disfunction, preload is high but relaxation is low. E/A ratio is high in the normal diastolic function (normal value 1.6). 20

21 Changing in diastolic function during the correction of cardiomyopathy. E/A ratio is initially elevated because of high LA pressure, after improvement it dropped to pathological values which reflects decreased compliance of hypertrophied LV. After regretion and remodeling of dilatated ventricule wall, E/A rate rose near normal value. Töz H, Özerkan F. Et al 1998AJKD 21

22 MAP (mmhg) Significant improvement of low Ejection fraction (%) ejection fraction by ultrafiltration First Last First Last Heart failure findings disappeared in all patients Ejection fraction increased in all, from 31 ± 9% to 50 ± 9% BP increased in cases with low BP at baseline Valvular regurgitations disappeared or improved Toz H, Hemodial Int

23 Cardiac functions Ruthman KA et al NDT 1990 Peak velocity of early diastolic filling (PEDFV) is marker of LV compliance. Highest hypotensive episodes is seen in the patients with lowest PEDFV. These patients are also have LVH 23

24 DIALISIS PROCEDURE DIALYSATE COMPOSITION: o ACETATE: Acetate used for a long time to correct acidosis. Acetate can not be metabolized by some patients, and acidosis correction may not be achieved. Most important disadvantage of acetate dialysis is that it increases the tendency to DH by decreasing the peripheral resistance. This causes a decrease BP and causes decreases in BF (preload) to the heart. o SODIUM: Na concentaration most important osmotic factor fluid shifting from or to the cells. Therotically a 1% decrease in Na concentration would cause a decrease in ECV of 0.5 L in normal subject. While low-na dialysate is effective for hypervolemia, high Na dialysate can prevent IDH. But high Na dialysate causes thirst increase ECV and increase IDWG. In the literature there is conficting data for both application. There is no evidence for the benefit of Na ond/or UF profiling. EBPG group advised: High sodium profiling or high sodium dialysate ( 144 mmol/l) should only be used for the prevention of IDH if other methods have failed and as a temporary 24

25 DIALISIS PROCEDURE DIALYSATE COMPOSITION: CALCIUM: Conventional dialysate composition of calcium levels are with net positive calcium balance. o High calcium level of blood has positive inotropic effect on the heart. Low calcium dialysate is widely used to avoid calcium loading and its consequences. Low dialysate calcium may cause IDH. Van der Sande et al 1998 AJKD 25

26 EBPG advised that A dialysate calcium concentration of 1.25 mmol/l should be avoided in patients prone to IDH, (level II) and a dialysate calcium concentration of 1.50 mmol/l should be prescribed. MAGNESIUM: Low magnesium dialysate also causes IDH especially in combination with low calcium dialysate. Low (0.25 mmol/l) magnesium dialysate should be avoided, especially in combination with low calcium dialysate (Kyriazis 2004 KI) GLUCOSE : Glucose free dialysate also associated with increased risk of IDH especially in diabetics (Simic-Ogrizovic 2001 ASAIO). Ok E et al JASN 26

27 DIALISIS PROCEDURE FOOD INTAKE DURING THE HD SESSION: Food intake during dialysis increases the sensitivity for IDH. This is probably because of splancnic pooling of blood. Zocalli C 1989 Clin Nephrol. 27

28 DIALISIS PROCEDURE DIALYSATE TEMPARATURE: Odudu A et al JASN 28

29 DIALISIS PROCEDURE DIALYSATE TEMPERATURE: A randomized control study found reducing dialysate temparature 0.5 C could significantly decrease IDH episodes. (Maggiore et al 1981 Proc. Eu Dial. Transplant. Assoc) o In hypotensive prone patients, cool dialysate temperature dialysis (35-36º C) or blood temperature controlled feedback should be used o With cool temperature dialysis, dialysate temperature should be gradually reduced from 36.5 ºC downwards every week. o Dialysate temperatures below 35ºC should not be used. 29

30 DIALISIS PROCEDURE HEMOFILTRATION: 30

31 Hemodinamic stability with on-line HDF Low-flux HD, hemofiltration and predilution ol-hdf (246 pts in each arm) RCT, 2 year follow-up Locatelli F, J Am Soc Nephrol 2010 Reduction in intradialytic hypotension episodes with pre-dilution ol-hdf 31

32 ESHOL (High volume OL- HDF) Secondary outcomes A relative risk reduction of 22% for hospitalization in the HDF group (HR 0.78, 95%CI , p=0.001) 28% lower risk of intradialytic hypotension in the HDF group (HR 0.72, 95%CI , p<0.001) Maduell F et al. J Am Soc Nephrol 2013; 24:

33 DIALISIS PROCEDURE HEMOFILTRATION: In various studies, the incidence of IDH was found to be less during convective techniques compared to conventional hemodialysis treatment. o However, no difference in IDH or intra-dialytic blood pressure decline was observed when hemodialysis and convective treatments were matched for thermal and other confounding factors. EBPG advised hemo(dia)filtration techniques should not be considered a first-line option for the prevention of IDH 33

34 Patients at risk for DH o A cohort of 958 patients from 11 dialysis centers, 96 patients with frequent episodes of DH. Age, female sex, presence of diabetes mellitus, hyperphosphatemia, presence of coronary artery disease, and renal diagnosis other than glomerulonephritis and the use of nitrates were significantly higher in patients with frequent DH. (Tisler A et al. Kidn.and Blood Presure Research 2002) o %44 >65 age patients, %32 <20 age. (Capuano A et al. NDT 1990) o Cardiac abnormality: Diastolic disfunction (Van der Sande FM et al), Patients with LVH (Ritz E. et al) o Most of the studies (Severi et al, Stojceva et al, Frukawa et al, Lee PT et al, Sato M et al., Heber ME ) showed autonomous dysfunction, some did not (Nies et al., Straver B et al.). o Sometimes seasonal ( Cheung AK et al JASN ) 34

35 Symptoms of DH Typically DH occurs suddenly. Autonomic reflexes Two type can be distinguished o Bradycardic Nausea and vomiting o Tachycardic Dizziness, Drowsiness Headache Muscle cramps 35

36 Chazot C et al KI 1999 Cramps is a important problem during IDH. Gradualy decrease in frequency of IDH and cramps in a group of patients kept their dry weight. Pathophysiology is not known. No doubt about that this phenomenon is trigerred by UF. 36

37 VOLUME INTRADIALYTIC HYPOTENSION CARDIAC DEBIT X PERIPHERAL RESISTANCE Practical Consideration Salt restriction Freqent dialysis Longer dialysis Na remodeling & profiling UF profiling LV systolic disfunction LV diastolic disfunction Venous return Inadequet e refill Removal rate>refill rate Target weight<dry weight Osmotic disequibrium Bezold jarisch reflex Central sympathetic drive Receptor desensitation Thermal imbalance Antihypertensive Rx Practical Consideration Cold dialysis Freqent dialysis Longer dialysis Increased Ca in bath Midrodine 37

38 STRAFIED APPROCH PREVENTING IDH EBPG Working Group 2007 NDT First line approach (consider each) dietary counselling (sodium restriction) refraining from food intake during dialysis, the use of bicarbonate as dialysis buffer use of a dialysate temperature of 36.5ºC reconsider dry weight check antihypertensive agents Second line approach (consider each) gradual reduction of dialysate temperature from 36.5ºC downward (lowest 35ºC) or temperature feedback control Vena cava echography to assess dry weight Prolonging dialysis time Avoid low calcium dialysate, use 1.50 mmol/l Echocardiographic evaluation Individualised blood volume controlled feedback Increase dialysis frequency Third line approach (only if other treatment options have failed) Switch to peritoneal dialysis Convective treatments Sodium profiling or high sodium dialysate L-carnitine supplementation

39 Take Home Messages Strict salt-free diet to limit IDWG Reconsider dry weight assesment occasionally Post HD weight should decrease gradually Withdraw antihypertensive Rx The extensive IDWG, and the shorter dialysis time, the more DH will occur Longer dialysis time is effective for DH, Reducing the dialysate temperature,is a helpful tool for the patients who are prone to hypotension 39

40