Impact of ischemic postconditioning with lactate-enriched blood on early inflammation after myocardial infarction

Postconditioning with Lactate-Enriched Blood for Reducing Lethal Reperfusion Injury in Humans

Ischemic myocardium cannot survive without reperfusion. However, reperfusion of the ischemic myocardium paradoxically induces myocyte death; this phenomenon is termed lethal reperfusion injury. To date, no effective approach has been demonstrated for ST-segment elevation myocardial infarction (STEMI) in clinical settings. Recently, we demonstrated a novel approach for cardioprotection, termed postconditioning with lactate-enriched blood (PCLeB). PCLeB comprises intermittent reperfusion and timely coronary injections of lactated Ringer's solution, which is implemented at the beginning of reperfusion. This approach is aimed at reducing lethal reperfusion injury via prolonging intracellular acidosis during the early period of reperfusion, compared with the original postconditioning protocol. Patients with STEMI treated using PCLeB have reported positive outcomes. This article represents an effort, with a perspective different from current insights, toward preventing lethal reperfusion injury, in light of the historical background of reperfusion injury research. PCLeB is considered the new approach for cardioprotection.

State-of-the-art methods for the treatment of severe hemorrhagic trauma: selective aortic arch perfusion and emergency preservation and resuscitation-what is next?

Trauma is a primary cause of death globally, with non‐compressible torso hemorrhage constituting an important part of “potentially survivable trauma death.” Resuscitative endovascular balloon occlusion of the aorta has become a popular alternative to aortic cross‐clamping under emergent thoracotomy for non‐compressible torso hemorrhage in recent years, however, it alone does not improve the survival rate of patients with severe shock or traumatic cardiac arrest from non‐compressible torso hemorrhage. Development of novel advanced maneuvers is essential to improve these patients’ survival, and research on promising methods such as selective aortic arch perfusion and emergency preservation and resuscitation is ongoing. This review aimed to provide physicians in charge of severe trauma cases with a broad understanding of these novel therapeutic approaches to manage patients with severe hemorrhagic trauma, which may allow them to develop lifesaving strategies for exsanguinating trauma patients. Although there are still hurdles to overcome before their clinical application, promising research on these novel strategies is in progress, and ongoing development of synthetic red blood cells and techniques that reduce ischemia‐reperfusion injury may further maximize their effects. Both continuous proof‐of‐concept studies and translational clinical evaluations are necessary to clinically apply these hemostasis approaches to trauma patients.

Reduced Plasma NT-proBNP Levels Months after Myocardial Infarction Postconditioned with Lactate-Enriched Blood

Background: We recently reported a new approach, namely postconditioning with lactate-enriched blood (PCLeB), for cardioprotection in patients with ST-segment elevation myocardial infarction (STEMI). Objectives: We examined the effects of PCLeB on plasma NT-proBNP levels months after myocardial infarction (MI). Methods: The study included consecutive patients (n = 31) undergoing percutaneous coronary intervention (PCI) for anterior STEMI within 12 h of symptom onset in our hospital between March 2014 and August 2018. We retrospectively compared plasma NT-proBNP levels several months after MI in these patients with those in historical control patients (n = 32). The control patients included consecutive patients who underwent successful PCI without PCLeB for anterior STEMI within 12 h of symptom onset in our hospital between March 2009 and February 2014. We compared the highest plasma NT-proBNP values 6–10 months after MI in the postconditioned patients with the lowest plasma NT-proBNP values 6–10 months after MI in the control patients. In the PCLeB protocol, the duration of each brief reperfusion was increased stepwise from 10 to 60 s. Lactated Ringer’s solution (30 mL) was injected directly in the culprit coronary artery at the end of each brief reperfusion. Each ischemic episode lasted 60 s. Results: Plasma NT-proBNP levels in the postconditioned patients months after MI (211 ± 207 pg/mL) were significantly lower than those in the control patients (516 ± 598 pg/mL; p < 0.0001). Conclusion: PCLeB was associated with reduced plasma NT-proBNP levels months after MI.

Muscle squeezing immediately after coronary reperfusion therapy using postconditioning with lactate-enriched blood

BACKGROUND

We recently reported a new approach for cardioprotection, postconditioning with lactate-enriched blood (PCLeB), and a patient with ST-segment elevation myocardial infarction (STEMI), in whom muscle squeezing of the culprit coronary artery was observed immediately after reperfusion with PCLeB. In this study, we examined the prevalence of muscle squeezing immediately after reperfusion in patients with anterior STEMI treated using PCLeB.

METHODS AND RESULTS

PCLeB is a modified postconditioning protocol that comprises intermittent reperfusion and timely coronary injections of lactated Ringer's solution. We treated 30 consecutive patients with anterior STEMI using PCLeB. Among the 30 patients, 4 patients exhibited muscle squeezing of the left anterior descending artery (LAD) immediately after reperfusion. We performed follow-up coronary angiography in 23 patients and found another patient who exhibited muscle squeezing of the LAD. Thus, of 30 patients, 5 were confirmed to have myocardial bridging and 4 exhibited muscle squeezing immediately after reperfusion with PCLeB. No patient died or experienced re-hospitalization for heart failure or recurrent ischemic events at 6 months except for one patient with malignancy.

CONCLUSION

Muscle squeezing immediately after reperfusion therapy is not a rare phenomenon in patients with anterior STEMI treated using PCLeB.

Lactated Ringer's solution for preventing myocardial reperfusion injury

Reperfusion of ischemic myocardium is crucial for salvaging myocardial cells from ischemic cell death. However, reperfusion itself induces various deleterious effects on the ischemic myocardium. These effects, known collectively as reperfusion injury, comprise stunned myocardium, reperfusion-induced arrhythmia, microvascular reperfusion injury, and lethal reperfusion injury. No approach has proven successful in preventing any of these injuries in the clinical setting. My colleagues and I recently proposed a new postconditioning protocol, postconditioning with lactate-enriched blood (PCLeB), for the prevention of reperfusion injury. This new approach consists of intermittent reperfusion and timely coronary injections of lactated Ringer's solution, aiming to achieve controlled reperfusion with cellular oxygenation and minimal lactate washout from the cells. This approach appeared to be effective in preventing all types of reperfusion injury in patients with ST-segment elevation myocardial infarction (STEMI), and we have already reported excellent in-hospital outcomes of patients with STEMI treated using PCLeB. In this review article, I discuss a possible mechanism of reperfusion injury, which we believe to be valid and which we targeted using this new approach, and I report how the approach worked in preventing each type of reperfusion injury.

Impact of postconditioning with lactate-enriched blood on in-hospital outcomes of patients with ST-segment elevation myocardial infarction

BACKGROUND

Reperfusion injury offsets the beneficial effects of reperfusion therapy for ST-segment elevation myocardial infarction (STEMI). In our previous reports, postconditioning with lactate-enriched blood (PCLeB) induced excellent microcirculation recovery and less inflammation in STEMI patients. This study aimed to determine the in-hospital outcomes of STEMI patients treated using PCLeB.

METHODS

Fifty-five consecutive STEMI patients were treated using PCLeB (Age 66.6±13.8years, 76.4% men) within 12h of symptom onset. In our modified postconditioning protocol, the duration of each brief reperfusion was prolonged from 10s to 60s in a stepwise manner. Lactated Ringer's solution (20-30mL) was injected directly into the culprit coronary artery at the end of each brief reperfusion and the balloon was quickly inflated at the lesion site, whereby lactate could be trapped inside the ischemic myocardium. Each brief ischemic period lasted 60s. After 7cycles of balloon inflation and deflation, full reperfusion was performed. Thereafter, stenting was performed and percutaneous coronary intervention (PCI) was completed.

RESULTS

The mean corrected thrombolysis in myocardial infarction frame count was 20.1±10.1 after PCI completion. The mean peak serum creatine kinase and creatine kinase-MB levels were 2751±2227IU/L and 276±181IU/L respectively. None of the study patients died during their hospital stay or required continuation of oral diuretic or inotropic therapy for heart failure on discharge.

CONCLUSIONS

PCLeB led to zero in-hospital mortality and no overt heart failure on discharge in 55 consecutive STEMI patients undergoing reperfusion therapy.