Cerebral Circulation During Retrograde Cerebral Perfusion: Evaluation Using Laser Speckle Flowgraphy

Ocular blood flow dynamics following sinus rhythm restoration through catheter ablation: laser speckle flowgraphy in patients with persistent atrial fibrillation

Aims

Laser speckle flowgraphy (LSFG) is a well-established tool renowned for its non-invasive and reproducible assessment of ocular blood flow. While rhythm control therapies, such as catheter ablation (CA), have shown promise in enhancing cognitive function in atrial fibrillation (AF) patients, the acute impact of CA on microcirculatory changes, particularly in ocular blood flow, remains a topic of limited understanding. The present study aims to delve into the potential of LSFG in detecting microcirculatory alterations following the restoration of sinus rhythm (SR) through CA in patients with AF.

Methods and results

We studied 8 paroxysmal AF (Paf) and 20 persistent AF (PeAF) patients (mean age 67 ± 6 years, 26% female) undergoing CA. Ocular blood flow was assessed using LSFG by measuring the mean blur rate (MBR) pre- and post-CA. Post-CA, all PeAF patients achieved SR restoration, resulting in a significant increase in tissue MBR (10.0 ± 2.2 to 10.8 ± 2.9, P = 0.021). In contrast, Paf patients showed no significant difference between pre- and post-MBR (12.0 ± 2.7 vs. 11.8 ± 2.6, P = 0.76).

Conclusion

LSFG analysis effectively identified microcirculatory changes in patients undergoing CA for PeAF, suggesting that therapeutic interventions targeting the heart may have broader implications for ocular and cerebral health, establishing a novel 'cardio-oculo-cerebral relationship'.

Advanced perioperative assessment of neurological function in acute Stanford A aortic dissection

OBJECTIVE

Acute Stanford Type A aortic dissection (AAAD) is a critical condition in vascular surgery, and total aortic arch replacement surgery is the preferred method to save patients' lives. In recent years, as clinical research has advanced, there has been a growing realization of the close association between poor postoperative outcomes in patients and neurological functional deficits. Neurological function monitoring is a medical technique used to evaluate and monitor the functional status of the nervous system.

METHODS

This monitoring involves the assessment of various aspects of the nervous system, including but not limited to nerve conduction velocity, neuromuscular function, electroencephalographic activity, and sensory nerve transmission. Neurological function monitoring has broad clinical applications and can be used to diagnose and monitor many neurological disorders, helping physicians understand patients' neurological functional status and guide treatment plans. During the postoperative recovery process, neurological function monitoring can assist physicians in assessing the potential impact of surgery on the nervous system and monitor the recovery of patients' neurological function.

RESULTS

Studies have shown that neurological function monitoring holds promise in predicting neurological functional prognosis and interventions for patients with aortic dissection.

CONCLUSION

Therefore, the primary objective of this study is to evaluate the effectiveness and reliability of various intraoperative neurological monitoring techniques, neuroimaging examinations, and biomarkers in predicting and assessing postoperative neurological outcomes in patients undergoing AAAD surgery.

Monitoring cardiac and ascending aortic procedures

Although cardiac and aortic operations have been successfully performed for more than 60 years, the risk of neurologic complications remains high. In particular, the rate of stroke with cardiac operations continues to be significant in the 1%-5% range. Similarly, the risk of stroke with aortic operations remains in the range of 7%-10% despite many years of improving techniques. Because of this persistently high risk, the use of intra-operative neurophysiologic monitoring (IONM) has the potential of improving outcomes. This chapter provides an overview of cardiac/aortic arch procedures from the neurophysiologic standpoint and discusses the roles of different monitoring modalities in detecting injury.

Influence of Acupuncture on Microcirculation Perfusion of Pericardium Meridian and Heart in Acute Myocardial Ischemia Model Rats

OBJECTIVE

To observe the influence of acupuncture on microcirculation perfusion of the pericardium meridian and heart in acute myocardial ischemia (AMI) rats and evaluate whether acupuncture can simultaneously affect the meridians and corresponding viscera. Additionally, acupoints at different meridians were compared and whether they exert the same effects was discussed.

METHODS

Totally 32 Sprague-Dawley rats were subjected to left anterior descending (LAD) ligation to develop an AMI model. Rats were divided into 4 groups, including AMI, acupuncture Neiguan (PC 6), Lieque (LU 7) and Qiansanli (LI 10) groups (n=8). Eight rats received only thoracotomy (sham-operated group). The rats in the acupuncture groups received manual acupuncture at PC 6, LU 7 and LI 10 acupoints for 15 min, respectively. The microcirculation perfusion of pericardium meridian and heart was monitored by laser speckle perfusion imager (LSPI) before, during and after acupuncture manipulation for 15 min. Subsequently, the perfusion unit (PU) was calculated and analyzed by PSI System.

RESULTS

After LAD, compared to pre-acupuncture stage, the heart microcirculation perfusion (HMP) in the AMI group decreased continuously at during-acupuncture (P>0.05) and post-acupuncture stages (P<0.05), and the pericardium meridian microcirculation perfusion (PMP) showed no significant differences at 3 stages (P>0.05). Compared to pre-acupuncture stage, the PMP and HMP in PC 6 group significantly increased during acupuncture manipulation (both P<0.05), and PMP decreased obviously after acupuncture (P<0.05). The PMP in the LU 7 and LI 10 groups were slightly elevated (both P>0.05); however, they were significantly reduced after acupuncture manipulation (both P<0.05). Additionally, HMP of LI 10 group was decreased significantly during acupuncture, especially compared to pre-acupuncture stage (P<0.05).

CONCLUSIONS

Acupuncture at PC 6 obviously increased the PMP and HMP in AMI rats, and the effects were superior to at LU 7 and LI 10 acupoints. It was further confirmed that acupuncture promoted qi and blood circulation, indicating that acupoint specificity exists and features a meridian-propagated effect.

Clinical Application of Laser Speckle Flowgraphy to Assess Changes in Blood Flow to the Foot After a Lumbar Sympathetic Ganglion Block: A Case Report

Background

The lumbar sympathetic ganglion block (LSGB) has been used as a diagnostic and therapeutic procedure for treating pain conditions such as neuropathic and ischemia-related pain, affecting the lower extremities. In general, an increase in skin temperature is useful in confirming the effectiveness of the sympathetic nerve block in clinical settings. However, the assessment of skin temperature in patients with peripheral arterial disease (PAD) occasionally provides false negatives.

Case Presentation

A novel technology, laser speckle flowgraphy (LSFG) enables noninvasive quantitative and qualitative blood flow assessments. LSFG is a novel neuro-monitor for quantitative blood flow detection in the optic nerve head during cardiac surgery. Herein, we report on measuring foot blood flow using LSFG before and after LSGB in a PAD patient. This research aimed to determine whether LSFG could detect any improvement in the dynamics of foot blood flow after an LSGB in a situation where changes in skin temperature alone could not determine the procedure's outcome.

Conclusion

LSFG can be used to assess blood flow changes in a foot with PAD, following a LSGB.

Quantitative laser speckle auto-inverse covariance imaging for robust estimation of blood flow

We present a quantitative model to provide robust estimation of the decorrelation time using laser speckle auto-inverse covariance. It has the advantages of independence from the statistical sample size, speckle size, static scattering, and detector noise. We have shown cerebral blood flow imaging through an intact mouse skull using this model. Phantom experiments and two animal models, middle cerebral artery occlusion, and cortical spreading depression were used to evaluate its performance.

Considerations for Reduction of Risk of Perioperative Stroke in Adult Patients Undergoing Cardiac and Thoracic Aortic Operations: A Scientific Statement From the American Heart Association

Perioperative stroke is one of the most severe and feared complications of cardiac surgery. Based on the timing of onset and detection, perioperative stroke can be classified as intraoperative or postoperative. The pathogenesis of perioperative stroke is multifactorial, which makes prediction and prevention challenging. However, information on its incidence, mechanisms, diagnosis, and treatment can be helpful in minimizing the perioperative neurological risk for individual patients. We herein provide suggestions on preoperative, intraoperative, and postoperative strategies aimed at reducing the risk of perioperative stroke and at improving the outcomes of patients who experience a perioperative stroke.

A surgical technique for ascending aorta, aortic arch and descending aorta replacement without cross-clamp, circulatory arrest or hypothermia

Treatment of the aneurysms comprising the aortic arch is challenging. Surgical reconstruction usually requires aortic cross-clamping, cardiac arrest, and even deep hypothermia for a bloodless field. In this report, we present our surgical technique providing normothermic ascending aorta, aortic arch, and proximal descending aorta replacement with selective cannulation and perfusion of the whole body.