Abstract
Objectives:
This study aims to compare intraoperative blood transfusion and perioperative outcomes for patients undergoing left ventricular assist device (LVAD) implantation before and after the implementation of a blood conservation protocol.
Methods:
This retrospective cohort study included patients who underwent LVAD implantation from June 2017 to October 2024 at our Hospital. The primary outcome was total intraoperative transfusion volume, and secondary outcomes included intraoperative transfusion volume and rates of red blood cells (RBC), fresh frozen plasma (FFP), platelets, and reoperation due to bleeding. Exploratory outcomes included mortality and serious complications before hospital discharge.
Results:
In total, 120 patients were included, with 62 receiving traditional care and 58 treated with blood conservation protocol. After protocol implementation, total intraoperative transfusion volume decreased from 3.23 ± 3.24 units to 1.74 ± 1.56 units (P = 0.002). The intraoperative RBC transfusion rate dropped from 30.6% to 8.6% (P = 0.003), and the transfusion volume fell from 1.00 ± 1.71 units to 0.31 ± 1.05 units (P = 0.009). In multivariate analysis, the protocol was significantly associated with reduced total intraoperative transfusion volume, lower RBC transfusion volume and rate, and shorter ICU and hospital stays, while not correlated with perioperative mortality or serious complications.
Conclusions:
The blood conservation protocol significantly reduced intraoperative transfusion in LVAD patients and expedited recovery.
Keywords: Blood conservation, blood transfusion, left ventricular assisted device
INTRODUCTION
The implantation of a left ventricular assisted device (LVAD) is associated with a highly increased bleeding risk and large amounts of blood products are used as a result.[1] 10%–30% of patients underwent early reexploration due to persistent bleeding after LVAD surgery,[2] which is associated with increased mortality and morbidity.[3,4] In a large US database analysis, intraoperative transfusion of any blood products was 5.7 ± 8.3 units per surgical case.[5] Besides all kinds of complications associated with allogenic blood transfusion, it is particularly harmful to LVAD implantation patients awaiting heart transplantation where allo-sensitization could lead to graft failure.[5] It is thus crucial to reduce blood transfusion for patients undergoing LVAD implantation.
Patients receiving LVAD therapy have an increased risk of bleeding and transfusion due to several reasons,[6] including preoperative anemia and coagulation disorders, massive intraoperative blood loss and hemodilution, as well as acquired von Willebrand factor (VWF) defect due to high shear stress forces in continuous-flow devices.[7]
Since bleeding related to LVAD implantation is caused by many factors, a simple improvement in one aspect is unlikely to bring major improvements. Instead, implementing a blood conservation protocol through multidisciplinary collaboration would be a more effective solution. Currently, there are no clinical studies documenting blood conservation protocols for patients undergoing LVAD implantation, prompting us to investigate this area. Our hospital has been conducting LVAD implantation surgeries since 2017. As the volume of LVAD implantation surgeries increases, we have implemented a multidisciplinary blood conservation protocol since 2023. This study aimed to compare the intraoperative blood transfusion and perioperative outcomes of patients before and after the implementation of the blood conservation protocol.
METHODS
Study design and study population
This single-center cohort study based on a prospective cohort encompassing all patients undergoing left ventricular assist device (LVAD) implantation from June 2017 (commencing with the LVAD program initiation) through October 30, 2024.[8] Perioperative outcomes, including postoperative mechanical ventilation duration, intensive care unit (ICU) length of stay, total hospitalization period, mortality, and major complications, were prospectively collected through longitudinal follow-up. By contrast, intraoperative transfusion parameters were retrospectively ascertained through systematic medical record abstraction. Clinical data were collected after obtaining the institutional ethics committee approval of our hospital, and informed consent was obtained for each patient. This study was conducted and reported in accordance with the STROBE guidelines.
The blood conservation protocol for LVAD patients
The blood conservation protocol has long been used in our institution but has only been strictly implemented on LVAD patients since 2023. We also modified our general blood conservation protocol specifically for LVAD patients. In Table 1, a detailed comparison between traditional care and the blood conservation protocol was demonstrated.
Table 1.
Comparison between traditional care and the blood conservation protocol
| Traditional care (2017-2022) | Blood conservation protocol (2023-2024) | |
|---|---|---|
| Preoperative | ||
| Manage anemia | Not standardized | For hemoglobin <12 g/dl: administer erythropoietin/iron therapy/Vitamin B12 |
| Treat malnutrition | Not standardized | Personalized nutrition consultations were provided for each patient, incorporating foods rich in protein and iron into their diets |
| Treat cardiac failure | Used for all patients | Used for all patients |
| Antiplatelet & Anticoagulation therapy | Ticagrelor was withdrawn preoperatively for a minimum of 3 days, clopidogrel for 5 days, aspirin for 5 days. Vitamin K antagonists are withheld for 3 to 5 days preoperatively aiming for an INR <1.5, and low molecular weight heparins were used as bridging therapy. | Direct-acting oral anticoagulants (DOAC) were discontinued two days preoperatively. In patients with renal or hepatic impairment, pre-operative plasma level of DOAC should be <30 ng/ml. |
| Intraoperative | ||
| Cell salvage | Used for all patients | Used for all patients |
| Priming solution | Priming solution around 1600 ml | Priming solution around 1100 ml |
| Antifibrinolytic agent | Not standardized | 50 mg/kg of tranexamic acid was administered to each patient |
| Thrombelastogram | Rarely used | Routinely used after cardiopulmonary bypass for patients with preoperative coagulation disorder, thrombocytopenia, or cardiopulmonary bypass time 3 hours. |
| Standard transfusion protocol for red blood cell (RBC) | Not strictly implemented | Standard protocol strictly implemented During cardiopulmonary bypass, RBC transfusion when hemoglobin <7 g/dL; After cardiopulmonary bypass, RBC transfusion when <8 g/dL Only when combine with SvO2 ≤ 55% or Lac ≥ 2.0 mmol/L |
| Prothrombin complex concentrate | Plasma was used as the main treatment for coagulation disorder. | Prothrombin complex concentrate and fibrinogen concentrate were used as the main treatments for coagulation disorder. |
| Temperature management | After cardiopulmonary bypass, maintain core body temperature ≥36.0°C by adjusting room temperature and using the circulating-water mattresses | After cardiopulmonary bypass, additional measures were adopted to keep core body temperature above 36.0°C, including fluid warming and forced-air warming blanket. |
| Meticulous surgery | No fixed surgical team | A dedicated surgical team consisting of at least attending surgeons was established. Throughout the procedure, at least one experienced senior attending surgeon was present. |
Data collection
Demographic characteristics, etiology of heart failure, Interagency Registry of Mechanically Assisted Circulatory Support (INTERMACS) profile, New York Heart Association (NYHA) classification, echocardiography, right heart catheterization results, and comorbidities were collected for each patient. Preoperative laboratory values such as hemoglobin level, platelet counts, and coagulation parameters were retrieved from the first test after hospital admission. Intraoperative data, including operation type, redo cardiac surgery, and detailed transfusion information, were collected through medical record review. Postoperative outcomes including postoperative mechanical ventilation duration, ICU stay, hospital stay, mortality, and major complications, were prospectively collected through longitudinal follow-up.
Study outcomes
The primary outcome was total intraoperative transfusion volume. The secondary outcomes were red blood cell (RBC), fresh frozen plasma (FFP), platelet (PLT) transfusion volume and transfusion rate, and the rate of reoperation due to bleeding. Exploratory outcomes included postoperative mechanical ventilation time, postoperative ICU length of stay, postoperative hospital length of stay, death, renal failure requiring continuous renal replacement therapy (CRRT), right heart failure, ventricular arrhythmia, ST segment elevated myocardial infarction (STEMI), stroke, respiratory failure, hepatic failure, and LVAD thrombosis before hospital discharge. All complications were reviewed and assessed according to INTERMACS adverse event definitions.
Statistical analysis
Quantitative data were exposed as mean ± standard deviation (SD) if normally distributed or as median and interquartile range (IQR) if not. Categorical data were expressed as absolute numbers and percentages. For normally distributed quantitative data, comparisons between groups were performed using the two independent sample t-tests. For non-normally distributed quantitative data, comparisons between groups were performed using the Mann–Whitney U test. For categorical data, we used χ2 or Fisher exact tests.
Baseline information between the two groups was assessed for heterogeneity. Unbalanced baseline characteristics that were clinically relevant to the outcomes were included in multivariate analysis. Multivariable linear regression was used to determine the association of the blood conservation protocol with transfusion volume, mechanical ventilation time, ICU, and hospital length of stay. Multivariate Logistic regression was used to determine the association of the blood conservation protocol with transfusion rate, reoperation rate, death, and postoperative complications. All tests were two-sided, and a P-value of < 0.05 was considered statistically significant. This study used SPSS V.26.0 software (IBM, New York, USA) for data analysis.
RESULTS
120 patients who underwent LVAD implantation from 6/26/2017 to 10/30/2024 were identified. Three types of LVAD devices were used (CH-VAD, CorHeart 6, and EVAHEART), all of which were continuous flow devices independently developed in China. Among them, 62 received traditional care, and 58 were treated with the blood conservation protocol. Preoperative and intraoperative characteristics of both groups are presented in Table 2. There were significant differences between the two groups in age, INTERMACS profile, preoperative FAC, preoperative hemoglobin and APTT levels, as well as the percentage of patients who underwent concomitant cardiac operations (i.e., coronary artery bypass, valvular plasty) together with LVAD implantation.
Table 2.
Baseline Characteristics of the study population
| Index | Traditional care (n=62) | Blood conservation (n=58) | P |
|---|---|---|---|
| Age, year | 44.95±13.08 | 51.19±15.96 | 0.021 |
| Male | 53 (85.4%) | 54 (93.1%) | 0.180 |
| Height, cm | 173.20±8.41 | 171.26±8.71 | 0.218 |
| Weight, cm | 69.25±13.83 | 68.48±16.57 | 0.718 |
| Etiology of heart failure | 0.698 | ||
| Dilated cardiomyopathy | 39(62.9%) | 37(63.8%) | |
| Ischemic etiology | 13(21.0%) | 14(24.1%) | |
| Valvular disease | 9(14.5%) | 5(8.6%) | |
| Congenital heart disease | 1(1.6%) | 2(3.4%) | |
| NYHA classification | 0.683 | ||
| Class III | 10(16.1%) | 11(19.0%) | |
| Class IV | 52(83.8%) | 47(81.0%) | |
| INTERMACS profile | 0.002 | ||
| Profile 1 | 11(17.7%) | 2(3.4%) | |
| Profile 2 | 32(51.6%) | 22(37.9%) | |
| Profile 3 | 14(22.6%) | 31(53.4%) | |
| Profile 4 | 5(8.1%) | 3(5.2%) | |
| Preoperative mPAP, mmHg | 29.37±9.38 | 27.97±11.54 | 0.647 |
| Preoperative CO, L/min | 3.33±1.20 | 3.66±1.19 | 0.291 |
| Preoperative LVEF, % | 23.45±4.12 | 23.97±5.31 | 0.549 |
| Preoperative LVEDD, mm | 78.66±11.53 | 75.77±10.57 | 0.160 |
| Preoperative FAC, % | 26.09±7.64 | 32.25±9.85 | 0.007 |
| Preoperative TAPSE, mm | 15.09±3.13 | 16.45±4.06 | 0.055 |
| Preoperative Mechanical ventilation | 6 (9.7%) | 4 (6.9%) | 0.582 |
| Preoperative hepatic failure | 11 (17.7%) | 5 (8.6%) | 0.142 |
| Preoperative renal failure | 12 (19.4%) | 11 (17.7%) | 0.957 |
| Preoperative PT, s | 17.28±6.05 | 17.39±6.78 | 0.806 |
| Preoperative APTT, s | 41.85±6.80 | 38.84±7.64 | 0.048 |
| Preoperative HGB, g/dL | 13.54±1.92 | 14.27±1.82 | 0.035 |
| Preoperative PLT, 109/L | 207.44±73.16 | 200.41±61.69 | 0.573 |
| Redo cardiac surgery | 1 (1.6%) | 3 (5.2%) | 0.309 |
| Concomitant cardiac surgeries | 34 (54.8%) | 21 (36.2%) | 0.017 |
NYHA=New York Heart Association, INTERMACS=Interagency Registry for Mechanically Assisted Circulatory Support, mPAP=mean pulmonary artery pressure, CO=cardiac output, LVEF=left ventricular ejection fraction, LVEDD=left Ventricular end diastolic diameter, FAC=fractional area change, TAPSE=tricuspid annular plane systolic excursion, PT=prothrombin time, APTT=activated partial thromboplastin time, HGB=hemoglobin, PLT=platelet
As shown in Table 3 and Figure 1, the total intraoperative transfusion volume significantly decreased from 3.23 ± 3.24 units to 1.74 ± 1.56 units (P = 0.002) following the implementation of the blood conservation program. The intraoperative RBC transfusion rate dropped from 30.6% to 8.6% (P = 0.003), with the transfusion volume reducing from 1.00 ± 1.71 units to 0.31 ± 1.05 units (P = 0.009). In addition, the intraoperative FFP transfusion rate significantly declined from 38.7% to 17.2% (P = 0.009), and the transfusion volume fell from 1.16 ± 1.96 units to 0.41 ± 0.96 units (P = 0.010). There was a trend toward fewer intraoperative platelet transfusions and a lower reoperation rate due to bleeding, although these differences were not statistically significant. The blood conservation group also experienced significantly shorter postoperative mechanical ventilation times, ICU stays, and overall hospital lengths of stay. No differences were observed in mortality or other serious complications before hospital discharge.
Table 3.
Comparison of clinical outcomes between the two groups
| Index | Traditional care (n=62) | Blood conservation (n=58) | P |
|---|---|---|---|
| Primary outcome | |||
| Total intraoperative transfusion volume, unit | 3.23±3.24 | 1.74±1.56 | 0.002 |
| Secondary outcomes | |||
| Intraoperative RBC transfusion rate | 19 (30.6%) | 5 (8.6%) | 0.003 |
| Intraoperative RBC transfusion volume, unit | 1.00±1.71 | 0.31±1.05 | 0.009 |
| Intraoperative FFP transfusion rate | 24 (38.7%) | 10 (17.2%) | 0.009 |
| Intraoperative FFP transfusion volume, unit | 1.16±1.96 | 0.41±0.96 | 0.010 |
| Intraoperative platelet transfusion rate | 62 (100%) | 58 (100%) | 1.000 |
| Intraoperative platelet transfusion volume, unit | 1.06±0.25 | 1.02±0.13 | 0.198 |
| Reoperation due to bleeding | 7 (11.3%) | 5 (8.6%) | 0.843 |
| Exploratory outcomes | |||
| Mechanical ventilation time/h | 115.56±352.86 | 19.97±7.13 | 0.041 |
| ICU length of stay/d | 34.79±42.87 | 18.11±10.95 | 0.006 |
| Hospital length of stay/d | 53.79±62.19 | 33.56±15.08 | 0.022 |
| Death | 3 (4.8%) | 0 (0%) | 0.090 |
| Renal failure requiring CRRT | 5 (8.1%) | 3 (5.2%) | 0.526 |
| Right heart failure | 6 (9.7%) | 6 (10.4%) | 0.903 |
| STEMI | 1 (1.6%) | 0 (0%) | 0.331 |
| Ventricular arrhythmia | 4 (6.5%) | 5 (8.6%) | 0.652 |
| Stroke | 2 (3.2%) | 1 (1.7%) | 0.525 |
| Hepatic failure | 3 (4.8%) | 1 (1.7%) | 0.342 |
| Respiratory failure | 5 (8.1%) | 4 (6.9%) | 0.808 |
| LVAD thrombosis | 1 (1.6%) | 0 (0%) | 0.331 |
RBC=red blood cells, FFP=fresh frozen plasma, ICU=intensive care unit, CRRT=continuous renal replacement therapy, STEMI=ST segment elevated myocardial infarction, LVAD=left ventricular assisted device
Figure 1.
Comparison of blood transfusion between the two groups. (a) The comparison of blood transfusion rate between the two groups, and (b) The comparison of blood transfusion volume between the two group
Table 4 showed the results of multivariate analysis. Multivariable linear regression analysis revealed that the blood conservation protocol was associated with a significant reduction in total intraoperative transfusion volume (P = 0.046). In addition, the multivariate analysis indicated that the protocol correlated with a decreased intraoperative RBC transfusion rate (P = 0.042, OR = 0.02) and lower transfusion volume (P = 0.046). While there was a trend toward reduced intraoperative FFP transfusions, platelet transfusions, and reoperations due to bleeding, these findings were not statistically significant. Regarding exploratory outcomes, the multivariate analysis demonstrated that the blood conservation program was linked to shorter ICU stays (P = 0.031) and hospital lengths of stay (P = 0.049), with a tendency to reduce mechanical ventilation time, although this trend was not significant. Furthermore, the multivariate analysis indicated that the blood conservation program did not correlate with mortality or any serious complications before hospital discharge.
Table 4.
Multivariate analysis of primary outcome, secondary and exploratory outcomes
| Index | Mean difference/Odds Ratio (95% CI) | P |
|---|---|---|
| Primary outcome | ||
| Total intraoperative transfusion volume, unit* | -1.2 (-2.4, -0.02) | 0.046 |
| Secondary outcomes | ||
| RBC transfusion volume* | -0.7 (-1.4, -0.01) | 0.046 |
| FFP transfusion volume* | -104.6 (-244.2, 35.1) | 0.139 |
| PLT transfusion volume* | -0.005 (-0.07, 0.06) | 0.875 |
| RBC transfusion rate† | 0.02 (0, 0.9) | 0.042 |
| FFP transfusion rate† | 0.5 (0.1-2.1) | 0.340 |
| Reoperation due to bleeding† | 0.3 (0.02-2.8) | 0.270 |
| Exploratory outcomes | ||
| Mechanical ventilation time* | -106.1 (-275.7, 63.5) | 0.215 |
| ICU length of stay* | -16.8 (-32.0, -1.6) | 0.031 |
| Hospital length of stay* | -29.8 (-59.5, -0.07) | 0.049 |
*Multivariable linear regression was used. †Multivariate Logistic regression was used. Age, INTERMACS profile, preoperative APTT, preoperative HGB, preoperative FAC, and concomitant cardiac surgeries were included in the multivariate analysis. RBC=red blood cell, FFP=fresh frozen plasma, PLT=platelet, ICU=intensive care unit
DISCUSSION
This study has confirmed for the first time that for LVAD patients, the implementation of a blood protection protocol significantly reduced the patient’s intraoperative blood transfusion and sped up the postoperative recovery process. To reduce blood transfusions associated with cardiac surgery, the Society of Thoracic Surgeons (STS) and Society of Cardiovascular Anesthesiologists established a task force in 2011 to identify patients at high risk for blood transfusions and recommended measures to reduce blood transfusion.[9] Since then, many cardiac surgery centers developed blood conservation protocols according to the STS recommendations, and several studies have shown that these protocols significantly reduced the amount of blood products used in coronary artery bypass surgeries and valve surgeries.[10,11] However, evidence for the implementation of blood conservation protocols in patients undergoing LVAD surgeries is quite sparse. Unlike general cardiac surgery patients, those undergoing LVAD implantation typically present with end-stage heart failure, compromised nutritional status, multi-organ dysfunction including hepatic failure, combined with surgical complexities that substantially elevate their risk of perioperative hemorrhage and transfusion requirements. Consequently, these patients necessitate a more tailored blood conservation protocol, as outlined in the subsequent section.
The total intraoperative blood transfusion during LVAD implantation in our hospital was 1.74 ± 1.56 units after the implementation of the blood conservation program, significantly lower than the level reported in previous literature. A retrospective review of 434 patients with LVAD implantation from 2003 to 2017 in the US reported that the mean intraoperative blood transfusion was over 18 units.[12] From a statewide database in the US, total intraoperative blood transfusion during LVAD implantation was 9.7 ± 10.9 units from 2004 to 2009, and 5.7 ± 8.3 units from 2010 to 2014.[5] The multidisciplinary blood conservation protocol is the key to reducing intraoperative blood transfusions in our hospital.
To reduce RBC transfusion, we took several preoperative and intraoperative measures. Preoperative anemia was actively managed with erythropoietin/iron therapy/Vit B12 following the latest guidelines.[13,14,15] Specifically, for LVAD implantation, we invited a preoperative nutrition consultation for every patient. Poor nutrition, sarcopenia, and cardiac cachexia were not uncommon in these patients with end-stage heart failure,[16,17] and research reported that malnutrition was a predictive factor for perioperative bleeding in cardiac surgeries.[18] For intraoperative management, we reduced the volume of priming solution thus minimizing hemodilution caused by cardiopulmonary bypass.[19] Establishing a standardized transfusion protocol also contributed to lowering intraoperative RBC transfusions. The latest STS guidelines advocate for a restrictive perioperative allogeneic RBC transfusion strategy over a liberal one.[13] According to these guidelines, allogeneic RBC transfusion is unlikely to enhance oxygen transport when hemoglobin levels exceed 10 g/dL, although no specific threshold is defined for intraoperative RBC transfusions.[13] A large, multicenter trial, The Transfusion Requirements in Cardiac Surgery ([TRICS] III), showed that a restrictive RBC transfusion strategy (hemoglobin threshold of <7.5 g/dL) in moderate to high-risk patients undergoing cardiac surgery was noninferior to a liberal transfusion strategy (hemoglobin threshold of <9.5 g/dL in the operating room or ICU and <8.5 g/dL on the non-ICU ward) regarding major morbidity and mortality.[20] The Intraoperative hemoglobin transfusion threshold recommended by the American Association for Thoracic Surgery in 2023 was 6.0 g/dl in general, and they also recommended “adopting a threshold according to local team consensus”.[21] Considering these guidelines and findings from large clinical trials, our hospital has established RBC transfusion standards for LVAD implantation at 7 g/dL during cardiopulmonary bypass and 8 g/dL after, but only when accompanied by SvO2 ≤ 55% or Lac ≥ 2.0 mmol/L. We set these standards because patients undergoing LVAD implantation typically have low cardiac output and may require higher hemoglobin levels to sustain systemic oxygen supply. Ultimately, the hemoglobin threshold for each patient should be determined based on the adequacy of tissue oxygen supply.
To minimize intraoperative FFP transfusions, effective preoperative management of heart failure is crucial. Some patients scheduled for LVAD implantation have liver dysfunction caused by heart failure before surgery.[22] For example, 16.6% of LVAD patients in our hospital had preoperative hepatic failure, which could cause severe coagulopathy that contributed to massive bleeding during LVAD implantation. All patients were treated in the heart failure-transplantation ward before LVAD surgery, where inotropic drugs and diuretics were used to optimize their heart failure condition, thereby enhancing intraoperative coagulation function. Another key factor in reducing intraoperative FFP transfusion was the proactive use of prothrombin complex concentrate (PCC). According to the STS guidelines, “a moderate level of evidence suggests that PCC is more effective than FFP for refractory coagulopathy in cardiac surgery.”[13] Several studies showed that PCC was more effective at reducing transfusion than plasma without an increased thrombotic risk in cardiac surgery patients,[23,24,25] although evidence on the use of PCC in LVAD patients is limited,[26] with the main concern being thrombotic complications. The primary reason for using PCC in LVAD patients at our hospital is to prevent intraoperative volume overload associated with FFP transfusions, thereby mitigating the risk of related right heart failure, as highlighted in the guidelines.[6] We have not observed an increase in thrombotic events among LVAD patients receiving PCC, although this finding requires confirmation through future studies. The platelet transfusion rate during LVAD implantation was 100% in our facility, largely due to our reliance on experience rather than clear indications for transfusion. The application of thromboelastography could significantly reduce intraoperative blood transfusion in cardiac surgery,[27,28] but its application was insufficient in our hospital. In the future, we will work on increasing the use of intraoperative thromboelastography and conduct platelet transfusions under the guidance of test results.
In addition to the aforementioned medical management, advancements in surgical techniques have played a crucial role in reducing intraoperative blood transfusions. Since the surgical team became more stable in 2023, their familiarity with LVAD implantation procedures has increased, gradually reducing operation time and enhancing hemostasis skills. During the procedure, we mandated the presence of at least one experienced senior attending surgeon, as evidence suggested that their expertise significantly reduced the reoperation rate after cardiac surgeries.[29] This underscores the significance of multidisciplinary collaboration within the blood conservation protocol for LVAD patients.
In this study, patients who were treated with the blood conservation protocol had significantly shorter postoperative length of ICU stay and hospital stay, and mechanical ventilation time also tended to shorten. Paone et al.[30] reported that for patients who underwent on-pump CABG, transfusion of as little as 1 or 2 units of RBCs was significantly associated with a longer postoperative recovery process. However, such an association has not been studied in LVAD patients. Previous studies showed that perioperative blood transfusions among patients undergoing LVAD implantation were associated with a higher risk for all-cause mortality, acute right heart failure, renal failure, and neurological events.[31,32] In our study, we observed no significant differences between the two groups regarding mortality and other complications before discharge. This lack of difference may be attributed to the small sample size and the low incidence of death and complications within this study.
This study was a single-center, retrospective, non–case-matched cohort analysis with several limitations. First, significant baseline differences were observed between the two study groups, which could potentially influence the outcomes. Second, as a single-center study, the blood conservation protocol and its findings may not be applicable to other institutions. Third, some data were retrospectively collected which may introduce biases or inaccuracies. Fourth, the statistical power to detect clinically meaningful differences in critical endpoints (e.g., 30-day mortality, major complications) may be constrained by the limited cohort size (n = 120). Finally, the implementation of the blood conservation protocol was not a discrete event; rather, it represented a gradual cultural shift, which made it difficult to isolate the effects of the blood conservation protocol from other concurrent changes in practice. We classified patients who underwent LVAD implantation after 2023 into the blood conservation group, as the protocol was officially introduced in our department at the beginning of that year.
In conclusion, the multidisciplinary blood conservation protocol significantly reduced intraoperative blood transfusions in patients undergoing LVAD implantation and facilitated faster postoperative recovery. While the results are promising, their validity requires confirmation through multicenter prospective randomized trials addressing current methodological limitations.
Author contributions
Study concept and design: Su Yuan, Jingfei Guo, Wenying Kang; Data collection: Xingtong Zhou, Xianqiang Wang, Fujian Duan; Analysis and interpretation of results: Jia Shi, Bingyang Ji, Haibo Chen; Daft manuscript preparation: Jingfei Guo, Wenying Kang; Manuscript review and revision: Su Yuan
Abbreviations
LVAD = left ventricular assisted device, INTERMACS = Interagency Registry of Mechanically Assisted Circulatory Support, CPB = cardiopulmonary bypass, LVEDD = left ventricular end-diastolic diameter, LVEDP = left ventricular end-diastolic pressure, VWF = von Willebrand factor, NYHA = New York Heart Association, ICU = intensive care unit, RBC = red blood cell, FFP = fresh frozen plasma, PLT = platelet, CRRT = continuous renal replacement therapy, STEMI = ST segment elevated myocardial infarction, IQR = interquartile range, SD = standard deviation, FAC = fractional area change, TAPSE = tricuspid annular plane systolic excursion, PT = prothrombin time, APTT = activated partial thromboplastin time, PCC = prothrombin complex concentrate, STS = the Society of Thoracic Surgeons, mPAP = mean pulmonary artery pressure, CO = cardiac output, DOAC = Direct-acting oral anticoagulants.
Conflicts of interest
There are no conflicts of interest.
Acknowledgment
The authors wish to acknowledge Lijuan Tian for helping with figure processing.
Funding Statement
Nil.
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