My Canadian Pharmacy and The BRIDGE
My Canadian Pharmacy and The BRIDGE

Amount of Cardioprotective Effects of Acute Normovolemic Hemodilution in Patients Undergoing Coronary Artery Bypass Surgery

26Feb,2016

Fluid BalanceFour patients who consented to take part were excluded because myocardial revascularization was performed without CPB (Fig 1). Data were obtained in 80 patients (39 in the ANH group and 41 in the control group).

Baseline Characteristics and Operative Data

The preoperative characteristics of the two groups were similar with regards to age, gender, body mass index, concomitant morbidity, left ventricular ejection fraction, and use of medications (Table 2). Also, the number of grafted coronary arteries as well as the durations of aortic cross-clamping, CPB, and surgery were comparable (Table 2).

Hemodynamics, Fluid Balance, and Hemoglobin Results

Following blood withdrawal and isovolemic compensation with colloids, hematocrit decreased from 41 ± 2 to 28 ± 1% (p < 0.001) and was accompanied by a significant increase in central venous pressure and a decrease in heart rate and rate-pressure product compared with baseline values (Table 3). No patients exhibited signs of myocardial ischemia as judged by the analysis of automated ST-segment and left ventricular wall motion monitoring. Prevent yourself from ischemia with remedies of My Canadian Pharmacy. Read more – “My Canadian Pharmacy: Researches of Cardioprotective Effects of Acute Normovolemic Hemodilution in Patients Undergoing Coronary Artery Bypass Surgery“.

Before CPB, hematocrit levels, heart rate, and rate-pressure-product remained significantly lower in the ANH group compared with the control group (Table 3). After weaning from CPB and at the end of surgery, hemodynamic data and hematocrit levels did not differ between the two groups.

Intraoperatively, the total volume of colloids was slightly but significantly higher in the ANH group compared with the control group. However, cumulative fluid balance and allogenic blood transfusion requirements were comparable in the two groups over the 24-h perioperative period (Table 4). In the ANH group, the autologous blood was reinfused during CPB in all the patients as the transfusion trigger was reached.

CPB

Primary Outcomes

In the two groups, troponin I concentrations were below the detection limit before CPB and increased significantly after arrival in the ICU. At 18 to 24 h, 40 to 48 h, and 72 h after aortic unclamping, myocardial release of troponin was significantly lower in the ANH group than in the control group (Table 5). Values for creatine kinase and myocardial fraction of creatine kinase were also comparable at the beginning of surgery and increased significantly after arrival in ICU in both groups. Compared with the control group, the release of the myocardial fraction of creatine kinase in the ANH group was significantly lower at arrival in ICU and 18 to 24 h after aortic unclamping (Table 5).

Secondary Outcomes

All patients survived, and one patient in each group met the ECG criteria for perioperative myocardial infarct. The groups were similar with respect to length of stay in the ICU and in the hospital, as well as the occurrence of noncardiac complications (Table 6). However, of 41 patients in the ANH group, 7 patients were administered dobutamine, compared with 15 patients in the control group (odds ratio, 0.35; confidence interval, 0.12 to 0.98; p = 0.04), and the total amount of dobutamine was significantly lower in the ANH group than in the control group. The combined incidence of arrhythmia and conduction disorders requiring transient cardiac pacing was also significantly lower in the ANH group, compared with the control group. Plasma troponin I concentrations (18 to 24 h after the end of CPB) were significantly higher in subgroups of patients receiving dobutamine infusion compared with those not requiring inotropic support (4.5 ± 3.1 ng/mL vs 2.2 ± 1.9 ng/mL in the control group, and 3.1 ± 2.3 ng/mL vs 0.7 ± 0.4 ng/mL in the ANH group, respectively).

Fig-1

Figure 1. Flow of the participants through the trial.

Table 2—Preoperative Characteristics and Operative Data of Patients Undergoing Myocardial Revascularization With CPB

Characteristics ANH (n = 41) Control (n = 39) p Value
Age, yr 67 (63-70) 65 (62-68) 0.7
BSA, m2 27 (26-28) 28 (24-30) 0.6
Male/female gender, No. 33/8 33/6 0.9
Medical history
Diabetes mellitus 12 (29) 9 (23) 0.7
Hypercholesterolemia 31 (76) 32 (82) 0.7
Hypertension 33 (80) 30 (77) 0.9
Prior myocardial infarction 17(41) 15 (38) 0.9
Left ventricular ejection fraction, % 54 (51-57) 55 (51-59) 0.8
Medications
p-Blockers 38 (93) 37 (95) 0.9
Nitrates 18(41) 17 (44) 0.8
Angiotensin-converting enzyme inhibitors/angiotensin II blockers 21 (51) 16(41) 0.9
Calcium blockers 10 (24) 7 (18) 0.7
Diuretics 7(17) 5 (13) 0.8
Statins 22 (54) 20 (51) 0.9
Aspirine taken < 72 h preoperatively 8 (20) 8(21) 0.9
Cross-clamp time, min 78 (63-93) 87 (70-104) 0.44
CPB time, min 114(101-127) 122 (111-133) 0.35
Surgical time, min 269 (251-287) 281 (263-300) 0.41
Grafted coronary arteries, No. (range) 3 (1-5) 3(1-4) 1

Table 3—Intraoperative Time Course of Hemoglobin and Hemodynamic Variables

Variables Baseline 1 After Hemodilution or Baseline 2 Sternotomy 10 min After Starting CPB After Weaning From CPB End of Surgery
Hematocrit, %
Control group 40 (38-42) ANH group 41 (39-43)
39 (37-43) 28 (27-29)t| 39 (37-43)
27 (26-9.3)t|
27 (24-29)| 20 (18—22)tt 25 (23-27)| 24 (22-26)| 27 (25-29)| 27 (24-30)|
Heart rate, beats/min
Control group 67 (64-70) ANH group 65 (61-69)
64 (61-77) 54 (51-57)t| 65(61-69)
55 (52-58)t|
81(77-85)| 78 (74-82)| 81(78-84)| 79 (75-83)|
Mean arterial pressure, mm Hg Control group 80 (76-84) ANH group 77 (74-80) 78 (74-82) 74 (71-77) 87(84-90) 85(81-89) 65 (52-68)| 64 (61-67)| 73(70-76) 74(71-77) 78 (74-82)
79 (75-84)
Rate-pressure product, mm Hg/beats/mii Control group 6,849 (6,102-7,496) ANH group 6,502 (6,140-6,904) 6,304 (5,960-6,640) 5,522 (5,290-5,755)t| 7,373 (6,895-7,851) 6,353 (5,812-6,894)t 8,263 (7,475-9,055) 7,746(7,311-8,181) 8,204 (7,667-8,741) 8,160 (7,427-8,893)
Central venous pressure, mm Hg Control group 11.4 (10.3-12.5) ANH group 11.8 (10.9-12.7) 11.6(10.7-12.5)
13.9(13.1-14.7)^
12.0(11.1-12.9) 13.1 (12.1-14.1) 14.4 (13.4-15.4)| 14.6 (13.4-15.8)| 14.6 (13.6-15.6)| 14.9 (13.7-15.1)|

Table 4—Intraoperative and Postoperative Fluid Balance and Allogenic Blood Transfusion

Variables ANH (n = 41) Control (n = 39) p Value
Intraoperative fluid balance, mL
Cristalloids 3,753 (3,427-4,079) 3,580(3,116-4,044) 0.5
Colloids 1,370 (1,270-1,470) 974 (850-1,098) 0.04
Urine output 942 (735-1,149) 739 (554-924) 0.14
Postoperative fluid balance (first 24 h), mL
Cristalloids plus colloids 2,864 (2,448-3,280) 3,444 (2,991-3,847) 0.07
Urine output 2,074 (1,808-2,340) 1,732 (1,452-2,006) 0.08
Chest tube drainage, mL/24 h 623(515-731) 567 (430-704) 0.5
Patients receiving RBC concentrates (intra- and postoperatively)
No. of patients 17 14 0.8
Mean (SD) of units per patient 0.9 (1.3) 1.0 (1.4) 0.7
Patients receiving fresh frozen plasma (intra- and postoperatively)
No. of patients 3 4 0.9
Mean (SD) of units per patient 0.3 (1.1) 0.3 (1.3) 0.9

Table 5—Perioperative Biological Markers of Cellular Injury

Variables Before Surgery After Weaning From CPB, h
1-3 18-24 40-48 72
Troponin I, ng/mL
Control group 0.04 (0.04-0.06) 1.64 (1.25-2.03)| 3.87 (3.15-4.59)! 3.16 (2.30-4.02)! 2.31 (1.63-2.97)!
ANH group 0.04 (0.03-0.05) 0.63 (0.51-0.75)t! 1.43 (1.02-1.84)т! 1.13 (0.84-1.42)t! 0.81 (0.58-1.02)T!
Creatinine phosphokinase, U/L
Control group 82 (76-88) 740(514-966)! 1,284 (928-1,640)! 1,120 (775-1,465)! 787 (592-982)!
ANH group 85 (77-93) 469(350-588)! 603(497-705)t! 490(449-541)t! 380(272-428)t!
Myocardial fraction of creatinine phosphokinase, U/L
Control group 13 (10-16) 35 (28-42) 71 (53-89)! 62 (40-84)! 38 (25-51)!
ANH group 10 (7-13) 28 (24-32) 29(23-35)t! 21(16-26)t 15 (12-18)
C-reactive protein, ng/dL
Control group 5
<
72(48-96)t 78 (52-94)!
ANH group 5
<
66 (46-86)t 71 (56-86)!

Table 6—Pharmacologic Cardiac Support and Perioperative Complications

Variables ANH (n = 41) Control (n = 39) p Value
Cardiac drugs
Dobutamine
No. of patients 7 15 0.04
Median dose (interquartile range), mg 71 (20-255)* 112(34-425) < >0.01
Norepinephrine
No. of patients 4 4 0.9
Median dose (interquartile range), mg 0.8 (0.4-2.1) 0.7 (0.3-2.1) 0.28
Cardiac complications, No. of patients 12* 26 < 0.01
New Q wave on ECG 1 1 0.9
Conduction block 8 12 0.36
Atrial fibrillation 10 17 0.11
Noncardiac complication, No. of patients
Postoperative ventilation > 24 h 1 2 0.9
Reoperation for bleeding 1 1 0.9
Stroke or transient cerebral ischemia 2 2 0.6
Renal dysfunction (creatinine > 120% of baseline) 3 3 0.7
ICU stay, median d (range) 2(1-5) 2 (1-7) 1.0
Hospital stay, median d (range) 12 (10-15) 13 (10-16) 1.0