Preoperative autologous plateletpheresis in patients undergoing open heart surgery

Blood conservation is an important aspect of care provided to the patients undergoing cardiac operations with cardiopulmonary bypass (CPB). It is even more important in patients with anticipated prolonged CPB, redo cardiac surgery, patients having negative blood group and in patients undergoing emergency cardiac surgery. In prolonged CPB the blood is subjected to more destruction of important coagulation factors, in redo surgery the separation of adhesions leads to increased bleeding and difficulty in achieving the haemostasis and in patients with negative blood group and emergency operations, the availability of sufficient blood can be a problem. Harvesting the autologous platelet rich plasma (PRP) can be a useful method of blood conservation in these patients. The above four categories of patients were prospectively studied, using either autologous whole blood donation or autologous platelet rich plasma (PRP) harvest in the immediate pre-bypass period. Forty two patients were included in the study and randomly divided into two equal groups of 21 each, control group (Group I) in which one unit of whole blood was withdrawn, and PRP group (Group II) where autologous plateletpheresis was utilised. After reversal of heparin, autologous whole blood was transfused in the control group and autologous PRP was transfused in the PRP group. The chest tube drainage and the requirement of homologous blood and blood products were recorded. Average PRP harvest was 643.33 +/- 133.51 mL in PRP group and the mean whole blood donation was 333.75 +/- 79.58 mL in the control group. Demographic, preoperative and intra operative data showed no statistically significant differences between the two groups. The PRP group patients drained 26.44% less (p<0.001) and required 38.5% less homologous blood and blood products (p<0.05), in the postoperative period. Haemoglobin levels on day zero (day of operation) and day three were statistically not different between the two groups. We conclude that autologous plateletpheresis is a better method of blood conservation in terms of better haemostasis, and less requirement of blood and blood products in the postoperative period as compared with the autologous whole blood donation. This technique can be especially useful in the above-mentioned categories of patients.     

Evaluation of leukocyte-depleted platelet concentrates obtained by in-line filtration

BACKGROUND AND OBJECTIVES: The use of leukocyte-depleted platelet concentrates (PCs) is justified, yet questions remain regarding their properties. We have assessed the in vitro quality of WBC-reduced PCs obtained by using a new in-line filter. MATERIALS AND METHODS: Twenty blood units were randomized for standard component preparation, or for processing including in-line leukodepletion of platelet-rich plasma using an ATS(TM) PL Pall filter. The resultant PCs were compared during storage for several in vitro platelet quality parameters, content of cytokines and anaphylatoxins, and coagulation markers. RESULTS: In-line filtration of platelet-rich plasma through ATS PL was highly efficient rendering PCs with 99.93% less white blood cells (WBCs) than standard PCs. During storage for up to 9 days, leukocyte-depleted units displayed platelet content, biochemical parameters, and platelet surface expression of glycoproteins Ibalpha, IIb/IIa, CD62 and CD63, similar to those of standard units. However, in-line leukocyte-reduced PCs displayed no significant accumulation of IL-6 and IL-8 during storage in contrast to standard units. Moreover, while storage promoted complement activation with C3a and C4a liberation in both WBC-reduced PCs and standard units, the concentration of these anaphylatoxins after the 9-day storage period was higher in the former group. Finally, all units, standard and leukocyte-reduced, displayed a similar storage-promoted rise in TGF-beta(1), and a mild prolongation of activated partial thromboplastin and prothrombin times. CONCLUSION: In-line filtration during component preparation appears as an easy and effective procedure for obtaining prestorage leukocyte-depleted PCs. During subsequent blood bank storage, these WBC-reduced PCs display, in comparison with standard PCs, normal in vitro platelet properties, decreased accumulation of cytokines IL-6 and IL-8, and increased complement activation.     

The 'cherry buffy-coat syndrome', a cause of decreased platelet yield in platelet concentrates obtained from buffy-coats

BACKGROUND AND OBJECTIVES: A large number of European blood centres, including our own, use the buffy-coat method for platelet production. In this article we describe a previously unnoticed phenomenon shown by a proportion of buffy-coats, which display an unusually bright cherry colour and low platelet counts. MATERIALS AND METHODS: We performed bacterial cultures, platelet counts, pO2, pCO2 and pH, and evaluated platelet activation by flow cytometry in cherry versus normal-colour (control) buffy-coats. In addition, we compared donor characteristics in the two groups and platelet counts in the packed red blood cells (RBC) obtained from the original donations. Finally, we monitored the frequency of cherry buffy-coats in the bags of three manufacturers, and determined the concordance rate of two trained technicians in detecting cherry buffy-coats. RESULTS: Bacterial cultures were negative. Cherry buffy-coats contained significantly fewer platelets, more O2, less CO2 and had a significantly higher pH than normal buffy coats. Platelet activation was slightly higher in cherry buffy-coats. RBC from donations yielding cherry buffy-coats contained a significantly higher number of platelets than controls. Donor characteristics were not significantly different. Cherry buffy-coats were significantly more frequent with bags from one manufacturer (24%) than from others (9% and 11.6%). The concordance study showed excellent agreement. CONCLUSIONS: Our hypothesis is that the cherry colour is caused by O2 accumulation in buffy-coats with low platelet counts. The latter may be caused by platelet activation and aggregation during blood processing. Further work is needed to determine the cause of this phenomenon, its frequency in different laboratories and means to prevent it.     

The impact of autologous platelet concentrates on endodontic healing: a systematic review

The current literature was reviewed to determine the impact of autologous platelet concentrates (APCs) on endodontic healing. All types of clinical study designs concerning any kind of endodontic treatment involving the application of APCs were included. Two independent reviewers searched three databases (PubMed, Embase, and Cochrane Library) for studies, complemented by hand search, until 16/1/2016. From the 423 identified records, 48 articles met the inclusion criteria. Selected randomized controlled clinical trials (RCTs) underwent Cochrane Collaboration’s risk-of-bias assessment and data extraction. Only two RCTs showed low risk of bias. There was considerable heterogeneity between the RCTs with regard to the type of therapy, type of APCs, assessment method, and study quality, and therefore the data could not be analyzed quantitatively. The included case reports/series and non-randomized comparative studies underwent qualitative analysis with the revised Methodological Index for Non-Randomized Studies (MINORS) and data extraction. The two comparative non-randomized studies scored qualitatively high, though the MINORS-scores of the case series and reports were dispersed. APCs were involved in five endodontic treatment modalities, namely apexification, regenerative endodontic procedures, pulpotomy, apical surgery, and treatment of endo-perio/perio-endo lesions. APCs seem to accelerate postoperative bone healing, augment the patients’ postoperative quality of life, aid further root development, and support maintenance/regaining of pulp vitality. No adverse events were reported. APCs in endodontic treatments seem to contribute to the healing of soft and hard tissues, though there is a lack of long-term high quality clinical trials and standardized treatment protocols.     

浅中低温体外循环不阻断心肌血流心内直视手术的临床对比研究

目的评价浅低温心脏不停跳及中低温不阻断心肌血流室颤性停搏下心内直视手术的临床对比效果。方法将263例患者分为中低温室颤性停搏组(94例)及浅低温心脏不停跳组(169例),常规插管建立体外循环,转机后阻断上、下腔静脉并降温,不阻断升主动脉(如手术位于主动脉根部的成人患者,则阻断升主动脉并经冠状静脉窦持续逆行灌注),不使用心脏停搏液;鼻咽温度分别于浅低温心脏不停跳(32±1)℃、中低温室颤性停搏(26℃～27℃)下行心内直视手术。结果浅低温组手术死亡4例,中低温组死亡3例。两组术中转机时间、术后呼吸机辅助时间、强心药物的使用及心律失常的发生情况等差异无统计学意义。无一例发生空气栓塞。结论浅低温心脏不停跳及中低温室颤性停搏下心内直视手术都具有较好的心肌保护效果,但在中低温下手术更有利于心内的操作,对血液的保护效果更优,可推荐成为一种安全、可行的心肌保护方法。     

Treatment with diltiazem preoperatively in open heart surgery for myocardial protection: experimental studies in dogs with chronic healed myocardial infarction

Calcium antagonists have become important in open heart surgery because of their effects on myocardial protection and cardioplegia. We evaluated the effect of pretreatment with the calcium antagonist diltiazem for myocardial protection in dogs with experimentally induced, chronic, healed myocardial infarction in a double-blind randomized study. One group consisted of 5 dogs treated with diltiazem (10 mg/kg bodyweight) for 7 days preoperatively, while a second group of 4 dogs were treated with placebo. All animals then underwent hypothermic, ischemic cardiac arrest (90 min) with extracorporeal circulation (ECC), followed by 30 min of reperfusion. Hemodynamic parameters were measured before and after ECC. An EKG was recorded during the entire procedure. The myocardium was studied by light microscopy for fresh necroses. The old, experimentally induced infarction scars were quantified by a new method that was developed for planimetry of the histological specimens. The diltiazem group compared with the placebo group showed myocardial cell necroses to a smaller extent. The hemodynamic studies supported the contention that diltiazem given preoperatively has a myocardial protective effect. These results encourage further studies on the use of diltiazem preoperatively for myocardial protection.     

The platelet count accuracy of platelet concentrates obtained by using automated analysis is influenced by instrument bias and activated platelet components

BACKGROUND AND OBJECTIVES: The blood platelet content (in numbers) of platelet concentrates is required for production quality control and to predict clinical responses. MATERIALS AND METHODS: This study compared the performance of automated counting from impedance and optical instruments to data from immunoplatelet reference analysis. RESULTS: All methods showed good linearity with evidence of significant instrument-specific deviations from the line of agreement. Relational formulae largely corrected bias, but did not resolve platelet count variability. A second confounding factor, related to the proportion of small (activated) platelets, was also shown to contribute to intermethod discrepancies. CONCLUSIONS: Blood processing centres should establish correction factors for each instrument compared to reference methods, such as the immunoplatelet count.     

Sternal tuberculosis after open heart surgery

We present a 68-y-old female who had undergone aortocoronary bypass and developed Staphylococcus aureus sternal osteomyelitis. Despite prolonged therapy with different antibiotics and several local debridements and drainage, the wound remained open and suppurative. Only after sternectomy and wide excision of infected costal cartilage was the diagnosis of sternal tuberculosis made, 24 months later. This case illustrates the necessity of a high degree of suspicion to diagnose this very rare entity which coexists with more common causes of sternal osteomyelitis.