The Use of Intraoperative Microvascular Doppler in Vascular Neurosurgery: Rationale and Results-A Systematic Review

Surgical treatment of neurovascular lesions like intracranial aneurysms, arteriovenous malformations and arteriovenous dural fistulas is still associated with high morbidity. Several recent studies are providing increasing insights into reliable tools to improve surgery and reduce complications. Inadvertent vessel compromise and incomplete occlusion of the lesion represent the most possible complications in neurovascular surgery. It is clear that direct visual examination alone does not allow to identify all instances of vessel compromise. Various modalities, including angiography, microvascular Doppler and neurophysiological studies, have been utilized for hemodynamics of flow vessels in proper clipping of the aneurysm or complete obliteration of the lesion. We intended to review the current knowledge about the intraoperative microvascular Doppler (iMDS) employment in the most updated literature, and explore the most recent implications not only in intracranial aneurysms but also in neurovascular lesions like arteriovenous malformations (AVMs) and arteriovenous dural fistulas (AVDFs). According to the PRISMA guidelines, systematic research in the most updated platform was performed in order to provide a complete overview about iMDS employment in neurovascular surgery. Twelve articles were included in the present paper and analyzed according to specific research areas. iMDS employment could represent a crucial tool to improve surgery in neurovascular lesions. The safety and effectiveness of the surgical treatment of neurovascular lesions like intracranial aneurysm and other neurovascular lesions like AVMs and AVDFs requires careful and accurate consideration regarding the assessment of anatomy and blood flow. Prognosis may depend on suboptimal or incomplete exclusion of the lesion.

Nailfold video-capillaroscopy in the study of cardiovascular disease: a systematic review

OBJECTIVES

Nailfold video-capillaroscopy (NVC) is an inexpensive method of assessing microcirculation. We reviewed the literature to assess whether changes to the nailfold capillaries exist in patients with cardiovascular disease (CVD).

METHODS

We searched PubMed, Scopus and Cochrane Library databases for original research articles relating to the use of noninvasive microvascular assessment in patients with CVD. Methodological quality was assessed with the 'Quality Assessment Tool for Observational Cohort and Cross-sectional Studies.' The results obtained from NVC were analysed qualitatively and compared with other forms of microvascular assessment.

RESULTS

In total 2759 articles were screened, of which 22 studies involving 562 patients (~40% women) with CVD were included. Mean age ranged between 3.7-68.4 years (cases) and 4.0-58.0 years (controls). Reduced capillary density and increased capillary dimensions were seen in patients with pulmonary arterial hypertension (PAH). Among patients with systemic sclerosis, advanced scleroderma patterns can be used to identify patients with or at risk of developing PAH. Functional nailfold changes precede structural changes in patients with hypertension. However, the studies were heterogeneous in the diagnosis of disease and the measurement of nailfold parameters. Most studies did not exclude conditions with altered nailfold features, and only one study performed a power calculation. Furthermore, abnormal nailfold findings are present in patients without systemic disease.

CONCLUSIONS

Structural and functional changes to the nailfold are a feature of established CVD and precede the development of PAH. However, heterogeneity in measurement and abnormal findings in healthy participants limit their use in the wider population.

Overview of Biofluids and Flow Sensing Techniques Applied in Clinical Practice

This review summarizes the current knowledge on biofluids and the main flow sensing techniques applied in healthcare today. Since the very beginning of the history of medicine, one of the most important assets for evaluating various human diseases has been the analysis of the conditions of the biofluids within the human body. Hence, extensive research on sensors intended to evaluate the flow of many of these fluids in different tissues and organs has been published and, indeed, continues to be published very frequently. The purpose of this review is to provide researchers interested in venturing into biofluid flow sensing with a concise description of the physiological characteristics of the most important body fluids that are likely to be altered by diverse medical conditions. Similarly, a reported compilation of well-established sensors and techniques currently applied in healthcare regarding flow sensing is aimed at serving as a starting point for understanding the theoretical principles involved in the existing methodologies, allowing researchers to determine the most suitable approach to adopt according to their own objectives in this broad field.

[Ocular microcirculation after revascularization of the internal carotid artery in the early postoperative period]

Carotid artery stenosis is the most common cause of ischemic stroke and transient ischemic attacks in the population of developed countries. Carotid endarterectomy (CEA) and carotid stenting (CAS) are effective treatments for carotid stenosis. In view of the need to improve the diagnosis of this condition and the anatomical relationship of the internal carotid arteries and vessels of the eye, studying retinal microvasculature has become an urgent problem. The theory suggesting that changes in ocular blood flow parameters may reflect disease status in patients with internal carotid artery (ICA) stenosis requires further investigation.

PURPOSE

To study the impact of CEA and CAS interventions on ocular blood flow in patients with clinically significant ICA stenosis in the early postoperative period.

MATERIAL AND METHODS

Thirty-two patients with hemodynamically significant stenosis (≥75%) of the left or right ICA were examined using optical coherence tomography angiography (OCT-A) and flowmetry before and after CEA or CAS in order to assess the changes in ocular blood flow parameters.

RESULTS

There were no significant differences in hemodynamic parameters in the eyes on the side of the stenotic and non-stenotic ICA before revascularization. In the early postoperative period (3-7 days) in the ipsilateral eyes, there was an increase in blood flow density and vascular density at the level of the superficial and deep plexuses in the macular area (p≤0.05), as well as an increase in the ocular blood flow volume, the level of tolerated intraocular pressure (p≤0.05) and a decrease in intraocular pressure (p≤0.05) bilaterally. In the contralateral eyes, after ICA revascularization there was a partial improvement in microcirculation parameters according to OCT-A (p≤0.05). Peripapillary blood flow density and peripapillary vessel density did not change significantly either on the ipsilateral or the contralateral side.

CONCLUSION

In patients with clinically significant ICA stenosis, ICA revascularization by stenting or endarterectomy contributed to an improvement in retinal microcirculation and retrobulbar blood flow in both eyes. OCT-A and flowmetry allow non-invasive assessment of retinal microvessels and retrobulbar blood flow, and the measurements provided by these methods can serve as valuable biomarkers for predicting and monitoring hemodynamic changes in patients who undergo CEA and CAS surgeries.

[Changes in ocular hemodynamics in patients recovered from COVID-19]

PURPOSE

To evaluate the severity of hemodynamic changes in the ocular vessels of patients recovered from COVID-19.

MATERIAL AND METHODS

The study included 44 patients (88 eyes) aged 28-60 years, among them 24 (54.5%) women and 20 (45.4%) men, with SARS-CoV-2 infection confirmed by PCR no more than 2 months prior to enrollment and with no ophthalmological complaints within 2 months before the disease, as well as 20 healthy volunteers (40 eyes). At the time of the study all patients had a negative PCR result for SARS-CoV-2. The patients were divided into 2 groups. The first group comprised 24 patients who did not take any anticoagulants during the treatment. The second group consisted of 20 patients who received anticoagulants (Rivaroxaban (Xarelto)) at a dosage of 10 mg per day for 1-1.5 months. The maximum systolic (Vs), end-diastolic (Vd) blood flow velocity, as well as resistance index (RI) in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were measured in all study patients with the ultrasound imaging system VOLUSON E8 Expert («Kretz», USA). Additionally, the flowmetry method was used to assess the volumetric ocular blood flow (VOBF) on Ocular Blood Flow Analyzer system («Paradigm Medical Industries, Inc.», USA).

RESULTS

In the first group, a decrease in Vs and Vd was noted amid a significant increase of RI in CRA and SPCA, as well as an increase of RI in OA compared with the age-normal values (p<0.05). In the second group, a decrease in Vs and Vd was noted amid a significant increase of RI in CRA, as well as a decrease in Vs in SPCA and an increase of RI in OA relative to the age-normal values (p<0.05). A decrease in VOBF was noted in the first group in comparison to the second group and the age norm (p<0.05).

CONCLUSION

Blood flow velocity parameters in the ocular vessels are reduced in patients recovered from COVID-19 compared to the age-normal values. There was a significant decrease in volumetric ocular blood flow parameters in COVID-19 patients who did not take any anticoagulants compared to the age-normal values. Anticoagulants intake has a positive impact on hemodynamic characteristics in the ocular vessels and volumetric ocular blood flow in patients with COVID-19.

A postresection perfusion deficit in the right colon is an independent predictor of perioperative outcome after major hepatectomy

BACKGROUND

There is a strong interaction between hepatic hemodynamics and perfusion in the splanchnic system. However, little is known about differences in perfusion in different splanchnic compartments and their changes after hepatectomy.

METHODS

Perfusion in various splanchnic compartments (ie, stomach, small intestine, right and left colon, liver) was assessed pre- and post-hepatectomy by intraoperative laser Doppler flowmetry. Differences of splanchnic perfusion between compartments were evaluated by ANOVA, and risk factors of postoperative complications (graded by the comprehensive complication index [CCI]) were analyzed by univariate and multivariate analyses. A prediction model of postoperative complications was developed.

RESULTS

A total of 50 and 29 patients with major and minor hepatectomy were enrolled. Splanchnic perfusion at baseline varied significantly across different splanchnic compartments with highest values in the small bowel and right colon (P < .001). Major hepatectomy induced a significant perfusion decrease in the stomach (P = .006), right colon (P < .001) and small bowel (P = .035). A postresection perfusion deficit in the right colon with values below 254 perfusion units (PU) was identified as an independent predictor of clinically relevant complications after major hepatectomy (concordance index: 0.79, 95% CI 0.66-0.87, P = .002). Bootstrap validation confirmed internal validity and excellent calibration.

CONCLUSIONS

Major hepatectomy causes significant reduction of splanchnic perfusion. An intraoperative posthepatectomy microcirculatory perfusion deficit of the right colon is a strong and independent predictor of clinically relevant postoperative complications after major hepatectomy.

Intraoperative completion studies in carotid endarterectomy: systematic review and meta-analysis of techniques and outcomes

Background

Declining perioperative stroke and death rates over the past 3 decades have been paralleled by an increasing use of intraoperative completion studies (ICS) following carotid endarterectomy (CEA). Techniques applied include angiography, intraoperative duplex ultrasound (IDUS), flowmetry, and angioscopy. This systematic review and meta-analysis is aiming on providing an overview of techniques and corresponding outcomes.

Methods

A PubMed based systematic literature review comprising the years 1980 through 2020 was performed using predefined keywords to identify articles on different ICS techniques. Pooled analyses and meta-analyses estimating risk ratios (RR) and 95% confidence intervals (CI) were performed to compare outcomes of different ICS modes to nonapplication of any ICS. I² values were assessed to quantify study heterogeneities.

Results

Identification of 34 studies including patients undergoing CEA with angiography (n=53,218), IDUS (n=20,030), flowmetry (n=16,812), and angioscopy (n=2,291). Corresponding rates of perioperative stroke were 1.5%, 1.8%, 3.6%, and 1.5%, perioperative stroke or death occurred in 1.7%, 1.9%, 2.2%, and 2.0%. Intraoperative surgical revision rates were 6.2%, 5.9%, and 7.9% after CEA with angiography, IDUS, and angioscopy, respectively. Compared to nonapplication of any ICS, the pooled analysis revealed angiography to be significantly associated with lower rates of stroke (RR 0.47; 95% CI, 0.36–0.62; P<0.0001) and stroke or death (RR 0.76; 95% CI, 0.70–0.83; P<0.0001). IDUS was significantly associated with lower rates of stroke (RR 0.56; 95% CI, 0.43–0.73; P<0.0001) and stroke or death (RR 0.83; 95% CI, 0.74–0.93; P=0.0018), whereas angioscopy showed a significant association with a lower stroke rate (RR 0.48; 95% CI, 0.033–0.68; P=0.0001), but no effect on the combined stroke or death rate. Angioscopy was associated with a higher intraoperative revision rate compared to angiography (RR 1.29; 95% CI, 1.07–1.54; P=0.006). The meta-analyses confirmed lower perioperative stroke or death rates for angiography (RR 0.83; 95% CI, 0.76–0.91) and IDUS (RR 0.86; 95% CI, 0.76–0.98) compared to non-application of any ICS, whereas flowmetry showed no significant association.

Conclusions

This study represents the first systematic literature review and meta-analysis on usage of ICSs in CEA. Data strongly indicate a significant beneficial effect of angiography, IDUS, and angioscopy on perioperative CEA outcomes. Any carotid surgeon should consider implementation of ICSs in his routine armamentarium.

[Peculiariities of diagnostic parameters in patients with acute myocardial lesion after coronary artery bypass grafting]

Annually, up to 850 000 coronary aortic bypass graft operations are performed worldwide. Despite modern technical equipment ensuring a high level of safety of the procedure, currently important remains a problem related to intraoperative myocardial damage in using artificial circulation. Early detection and clinical assessment of myocardial ischaemia often present a difficult task. This article deals with clinical, instrumental and laboratory methods of diagnosis, aimed at verification of an intraoperative cardiac lesion associated with graft dysfunction in coronary artery bypass grafting. Isolated electrocardiographic and echocardiographic signs of myocardial ischaemia between the comparison groups did not differ significantly. Analysing the markers of myocardial lesions, statistically significant differences were obtained only after 48 hours which, from the point of view of saving viable myocardium, is an utterly long-term interval. Studying the findings of intraoperative flowmetry showed statistically significant dependence between velocity characteristics, pulse index of shunts and their patency on angiographic examination. Thus, only combination of diagnostic parameters makes it possible to detect myocardial damage related to shunt dysfunction. This enables early determination of indications for performing bypass angiography and selection of the required therapeutic policy. Timely coronary artery angiography makes it possible to reveal defects of shunts and to timely perform surgical correction, preventing myocardial infarction.

Clinical comparison of sensitivity and specificity between sensibility and vitality tests in determining the pulp vitality of mandibular premolars

This clinical study was designed to compare cold pulp testing (CPT), heat pulp testing (HPT) and electric pulp test (EPT) with pulse oximetry (PO), flowmetry (FM) and thermometry (TM) in terms of sensitivity and specificity. Twenty premolar teeth in need of root canal treatment were included in the study. Pulp sensibility tests (CPT, HPT and EPT) along with vitality tests (PO, FM and TM) were performed. As the gold standard, the teeth were endodontically treated and pulp vitality was determined by direct visual observation. Sensitivity, specificity and accuracy values for each test were as follows: HPT 1, 1, 100%; CPT 1, 0.818, 90%; EPT 1, 0.909, 95%; PO 1, 0.545, 75%; TM 0.111, 0.272, 20%; and FM 0.444, 0.272, 35%, respectively. The most accurate test among all was HPT. PO was the most accurate vitality test.

Results of flowmetric assessment of composite Y-grafts and autovenous coronary artery bypass grafts

AIM

The purpose of the study was to perform intraoperative assessment of blood flow in coronary bypass grafts of the 'first' and 'third' order according to Calafiore A.M. with the help of the TTFM technique and to compare the obtained results.

PATIENTS AND METHODS

This retrospective, single-centre study enrolled a total of 222 patients subjected to coronary artery bypass grafting (CABG) from January to November 2017. Depending on the type of bypass grafting of the posterior interventricular artery (PIVA), the patients were divided into 2 groups. Group One consisted of 108 patients undergoing bypass grafting of the PIVA with the help of combined Y-grafts from the right internal thoracic artery (RTIA). Group Two was composed of 114 patients subjected to autovenous coronary artery bypass grafting of the PIVA. Blood flow was assessed with the help of the VeriQ MediStim® flowmeter after termination of extracorporeal circulation (ECC), at systolic pressure of 100-110 mm Hg. The parameters of blood flow were assessed using the 1.5- and 2-mm probes. In a specially designed protocol we registered the type of the shunt, the bypassed artery, and values of flowmetry parameters. We also evaluated the pattern of the flowmetric curve according to Takemi Handa et al. RESULTS: The obtained findings revealed a statistically significant difference in the values of Qmean (p=0.001), with the PI values in the groups not statistically differing (p=0.14). Thus, in patients with similar parameters influencing the volumetric velocity of blood flow (the degree of proximal stenosis, diameter of the bypassed artery, mean systolic AP and HR) the value of Qmean was higher in the group with coronary artery bypass grafting (CABG), i. e., in the group of the 'first-order' conduits. Therefore, an autovein directly anastomosed to the aorta experiences grater haemodynamic overload, which completely confirms the theory of Calafiore A.M.

CONCLUSION

First-order conduits (CABG) appear to experience greater wall strain because of greater haemodynamic overload as compared with third-order conduits (Y-grafts). A composite Y-graft may be an alternative technique of bypass grafting of the basin of the right coronary artery (RCA). A composite Y-graft has greater resistance to wall shear stress than an autovein anastomosed to the aorta.

[Functionality of mammary-coronary bypass grafts according to the data of intraoperative flowmetry]

Improvement of surgical treatment for ischaemic heart disease is one of the main trends in modern medicine. After the operation of coronary bypass grafting, further functioning of blood flow in the grafts largely depends upon its domination over the native blood flow in the target coronary arteries. Therefore, intraoperative diagnosis of functional competence of coronary bypass grafts by means of flowmetry is currently of special importance. The purpose of this study was flowmetric quantitative assessment of the curves of blood flow through the coronary bypass grafts, depending on the degree of stenosis of the target coronary arteries. A total of 135 patients were examined during our study. We evaluated the curves of blood flow through the bypass grafts from the left internal thoracic artery to the anterior descending artery. The bypass grafts were divided into three groups: the 1st group (n=47) with moderate stenosis of the coronary arteries (from 50 to 75%); the 2nd group (n=42) with a more pronounced lesion of the target vessel (from 75 to 99%), and the 3rd group (n = 46) with occluded coronary arteries (100%). It was revealed that the flow rate (Q, ml/min) in group one was lower (17±3.1) than in group two (33±5.3) and group three (45±3.4). Also, differences were revealed in the resistance index of the grafts: it turned out to be higher in group one (5.2±1.1) and group two (4.5±0.9) as compared with group three (1.8±0.5). However, there was no between-group difference in diastolic filling of the grafts, which amounted to 58±13, 61±10 and 64±9% for groups one, two and three, respectively. By the shape of the curve, we assessed the reverse systolic peak whose presence prevailed in the grafts of group one (15 of 47; 31.9%) and group two (11 of 42; 26.2%) as compared with that in the grafts of group three (5 of 46; 10.8%). The obtained findings confirm higher frequency of the presence of competitive blood flow in the grafts used on non-occluded coronary arteries.

[Flowmetrical features of the postoperative wound process in drug addicted patients with chronic odontogenic osteomyelitis of the jaws when using different surgical approaches]

The aim of the work was to study changes in local microhemodynamic indices in drug addicted patients in the course of the treatment of chronic odontogenic osteomyelitis. Assessment of tissue blood flow in gingival mucosa in patients with chronic osteomyelitis was performed using Laser doppler flowmetry. All patients were divided into two groups, namely treatment (n=21) and control (n=19). Sequestrectomy was performed to the patients from the treatment group with a bone defect closed with a concomitant use of PRP gel and FRP membranes. The same surgery was performed to patients from control group with a bone defect closed with iodoform tampon. During the study it was revealed that sequestrectomy with use of PRP gel and FRP membranes leads to rapid decrease in local postoperative inflammatory reactions, improvement of venous outflow and better functioning of microvessels endothelium and general optimization of the tissue healing process in drug addicted patients with chronic odontogenic osteomyelitis.

Recombinant human erythropoietin does not affect several microvascular parameters in well-trained cyclists

Recombinant human erythropoietin (rHuEPO) has been used as a performance-enhancing agent by athletes in a variety of sports. The resulting increase in hematocrit levels leads to increased blood viscosity and can affect blood flow, potentially increasing the athlete's risk of developing health complications. However, the actual effects of using rHuEPO on microvascular blood flow and post-occlusive reactive hyperemia are currently unknown. We therefore evaluated the effect of rHuEPO on the cutaneous microcirculation in well-trained cyclists using laser speckle contrast imaging (LSCI). This study was part of a randomized, double-blind, placebo-controlled, parallel trial designed to investigate the effects of rHuEPO in 47 well-trained adult cyclists (age 18-50 years). Subjects received a weekly dose of either rHuEPO or placebo for 8 weeks, and LSCI was performed at baseline, after a maximal exercise test in week 6, and before maximal exercise in week 8. Endpoints included basal blood flux, maximum post-occlusion reperfusion, and time to return to baseline. Despite an increase in hematocrit levels in the rHuEPO-treated group, we found no statistically significant difference in microvascular function measured between the rHuEPO-treated group and the placebo group. Our results suggest that the increased hematocrit levels in rHuEPO-treated well-trained cyclists are not associated with changes in microvascular blood flow or post-occlusive reactive hyperemia measured using LSCI.

Processing methods for photoacoustic Doppler flowmetry with a clinical ultrasound scanner

Photoacoustic flowmetry (PAF) based on time-domain cross correlation of photoacoustic signals is a promising technique for deep tissue measurement of blood flow velocity. Signal processing has previously been developed for single element transducers. Here, the processing methods for acoustic resolution PAF using a clinical ultrasound transducer array are developed and validated using a 64-element transducer array with a -6 dB detection band of 11 to 17 MHz. Measurements were performed on a flow phantom consisting of a tube (580  μm inner diameter) perfused with human blood flowing at physiological speeds ranging from 3 to 25  mm  /  s. The processing pipeline comprised: image reconstruction, filtering, displacement detection, and masking. High-pass filtering and background subtraction were found to be key preprocessing steps to enable accurate flow velocity estimates, which were calculated using a cross-correlation based method. In addition, the regions of interest in the calculated velocity maps were defined using a masking approach based on the amplitude of the cross-correlation functions. These developments enabled blood flow measurements using a transducer array, bringing PAF one step closer to clinical applicability.

Laser Doppler Assessment of Vasomotor Axon Reflex Responsiveness to Evaluate Neurovascular Function

The vasomotor axon reflex can be evoked in peripheral epidermal nociceptive C-fibers to induce local vasodilation. This neurogenic flare response is a measure of C-fiber functional integrity and therefore shows impairment in patients with small fiber neuropathy. Laser Doppler flowmetry (LDF) and laser Doppler imaging (LDI) are both techniques to analyze vasomotor small fiber function by quantifying the integrity of the vasomotor-mediated axon reflex. While LDF assesses the flare response following acetylcholine iontophoresis with temporal resolution at a single defined skin point, LDI records flare responses with spatial and temporal resolution, generating a two-dimensional map of superficial blood flow. LDF is characterized by a high intra- and interindividual measurement variability, which is smaller in LDI due to its spatial resolution. Nevertheless, LDI still lacks standardized methods for image analysis. Consequently, use of the technique currently remains on an experimental level. Here, we sought to review the current literature on laser Doppler assessment of vasomotor function and discuss potential future applications of established techniques as well as those that are still experimental.

Current Developments on Optical Feedback Interferometry as an All-Optical Sensor for Biomedical Applications

Optical feedback interferometry (OFI) sensors are experiencing a consistent increase in their applications to biosensing due to their contactless nature, low cost and compactness, features that fit very well with current biophotonics research and market trends. The present paper is a review of the work in progress at UPC-CD6 and LAAS-CNRS related to the application of OFI to different aspects of biosensing, both in vivo and ex vivo. This work is intended to present the variety of opportunities and potential applications related to OFI that are available in the field. The activities presented are divided into two main sensing strategies: The measurement of optical path changes and the monitoring of flows, which correspond to sensing strategies linked to the reconstruction of changes of amplitude from the interferometric signal, and to classical Doppler frequency measurements, respectively. For optical path change measurements, measurements of transient pulses, usual in biosensing, together with the measurement of large displacements applied to designing palliative care instrumentation for Parkinson disease are discussed. Regarding the Doppler-based approach, progress in flow-related signal processing and applications in real-time monitoring of non-steady flows, human blood flow monitoring and OFI pressure myograph sensing will be presented. In all cases, experimental setups are discussed and results presented, showing the versatility of the technique. The described applications show the wide capabilities in biosensing of the OFI sensor, showing it as an enabler of low-cost, all-optical, high accuracy biomedical applications.

Reduced peripheral vascular reactivity in refractory angina pectoris: Effect of enhanced external counterpulsation

AIMS

To examine if the skin microvascular bed is altered and can be modified by enhanced external counterpulsation (EECP) in patients with chronic refractory angina.

METHODS

Twenty patients diagnosed with refractory angina were divided into EECP (n = 10) or no EECP (n = 10) groups. The data were compared to matched healthy subjects (n = 20). The cutaneous forearm microvascular blood flow was measured by Laser-Doppler flowmetry. The vascular responsiveness to iontophoretic administration of acetylcholine (ACh), sodium nitroprusside (SNP) and local skin warming were studied. Measurements of Canadian Cardiovascular Society (CCS)-class, blood pressure and plasma samples were registered.

RESULTS

EECP patients showed reduced CCS-class compared to no EECP (P < 0.05). Both EECP and no EECP (P < 0.05) groups had decreased systolic blood pressure (SBP) as compared to SBP at baseline (P < 0.05). There was no difference in resting blood flow between the two refractory groups at baseline as well as after EECP and seven weeks of follow-up. Responses to heating, the responses to ACh and SNP in the cutaneous microcirculation were lower in both groups of refractory angina patients as compared to healthy subjects (P < 0.05). EECP patients corresponded positively to the treatment shown by reduced plasma level of soluble interleukin-2 receptor and CCS-class.

CONCLUSIONS

Refractory angina patients have reduced responsiveness in their cutaneous microcirculation to ACh, SNP and heat compared to healthy subjects. Although EECP reduced the CCS-class, this effect was not associated with improvements in responsiveness of the cutaneous microcirculation.

Intraobserver reproducibility and interobserver agreement of ultrasonic flowmetry using the velocity profile color doppler method in the common carotid artery

Application of the velocity profile method is recommended for reliable measurement of flow volume in larger vessels, and ultrasonic flowmetry is a useful clinical tool for this purpose. We used the velocity profile in conjunction with a minor modification in the conventional velocity profile method and examined the reproducibility of flowmetry from color Doppler data. Data of three examiners were allowed to analyze intraobserver reproducibility and interobserver agreement in the common carotid artery, and we measured flow volume in the peripheral vessels of healthy individuals. Estimated flow volumes in five healthy examinees were 350 to 550 ml/min and did not vary significantly between examiners. Interobserver correlation was good (r 1=0.63), but intraobserver correlations in two sonographers were excellent (r 1=0.85) in by one who was experienced in this method and poor (r 1=0.32) in the other. Good interobserver agreement and intraobserver reproducibility of experienced examiners suggests that this method is reliable. Values obtained with normal controls averaged 438±78 (mean±SD) ml/min and 449±64 ml/min, respectively, in the right and left carotid arteries (n=12) and 120±31 ml/min and 83±23 ml/min, respectively, in the right and left vertebral arteries (n=10). Normal values were 542±71 ml/min (n=11) in the right renal artery, 1210±211 ml/min in the abdominal artery (n=10), and 799±182 ml/min in the main portal vein (n=17). Arterial blood flow volume can measure reliably by the velocity profile color Doppler method.