Effect of enhanced external counterpulsation on coronary slow flow and its relation with endothelial function and inflammation: a mid-term follow-up study

The effects of enhanced external counter-pulsation on post-acute sequelae of COVID-19: A narrative review

Some of the millions of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have developed new sequelae after recovering from the initial disease, termed post-acute sequelae of coronavirus disease 2019 (PASC). One symptom is anxiety, which is likely due to three etiologies: brain structural changes, neuroendocrine disruption, and neurotransmitter alterations. This review provides an overview of the current literature on the pathophysiological pathways linking coronavirus disease 2019 to anxiety, as well as the possible mechanisms of action in which an increasingly scrutinized treatment method, enhanced external counter-pulsation (EECP), is able to alleviate anxiety. SARS-CoV-2 triggers increased inflammatory cytokine production, as well as oxidative stress; these processes contribute to the aforementioned three etiologies. The potential treatment approach of EECP, involving sequenced inflation and deflation of specifically-placed airbags, has become of increasing interest, as it has been found to alleviate PASC-associated anxiety by improving patient cardiovascular function. These functional improvements were achieved by EECP stimulating anti-inflammatory and pro-angiogenic processes, as well as improving endothelial cell function and coronary blood flow, partially via counteracting against the negative effects of SARS-CoV-2 infection on the renin-angiotensin-aldosterone system. Therefore, EECP could promote both psychosomatic and cardiac rehabilitation. Further research, though, is still needed to fully determine its benefits and mechanism of action.

Enhanced External Counterpulsation for the Treatment of Angina With Nonobstructive Coronary Artery Disease

Angina and nonobstructive coronary artery disease (ANOCA) is associated with poor outcomes and limited treatment options. Enhanced external counterpulsation (EECP) is a noninvasive treatment that involves applying external inflatable cuffs to the lower extremities to increase blood flow during diastole, followed by deflation during systole. Although EECP is approved for treatment in patients with refractory angina due to obstructive coronary artery disease, its effectiveness in treating patients with ANOCA with refractory angina is limited to small studies. We assessed the efficacy of EECP treatment in patients with ANOCA (defined as ≤50% stenosis in any major epicardial vessels) with refractory anginaby measuring changes in Canadian Cardiovascular Society (CCS) angina class, 6-minute walk test, Duke Activity Status Index (DASI), Seattle Angina Questionnaire 7 (SAQ7), and weekly anginal episodes pre-EECP and post-EECP treatment. A total of 101 patients with ANOCA with CCS class III/IV angina completed a full course of EECP treatment at 2 large EECP centers. In 101 patients with ANOCA the mean age (SD) of 60.6 (11.3) years and 62.4% of the cohort were women. We found significant improvements post-EECP treatment in CCS angina class (mean (SD) 3.4 (0.5) to 2.4 (2.9), p <0.001), 6-minute walk test (median 1200 (IQR 972 to 1411) to 1358 (1170 to 1600), p <0.001), DASI (mean (SD) 15.2 (11.6) to 31.5 (16.3), p <0.001), SAQ7 (mean (DS) 36.2 (24.7) to 31.5 (16.3), p <0.001), and weekly anginal episodes (mean (SD) 5.3 (3.5) to 2.4 (2.9), p <0.001). After EECP treatment, 71 patients (70.3%) had an improvement of ≥1 CCS angina class, including 33 (32.7%) patients improving by ≥2 CCS classes. In conclusion, in patients with ANOCA, EECP therapy reduces CCS angina class and improves exercise tolerance and capacity; and should be considered a part of optimal medical therapy.

Ischemia and no obstructive coronary arteries in patients with stable ischemic heart disease

A large proportion of patients with suspected obstructive coronary artery disease (CAD) is found to have ischemia with no obstructive coronary artery disease (INOCA). Based on current evidence, these patients are at increased risk of adverse cardiovascular events, even though they have no obstructive CAD. Importantly, INOCA is associated with recurrent clinical presentations with chest pain, impaired functional capacity, reduced health-related quality of life, and high healthcare costs. Underlying coronary microvascular dysfunction (CMD), through endothelium-dependent and independent mechanisms contribute to these adverse outcomes in INOCA. While non-invasive and invasive diagnostic testing has typically focused on identification of obstructive CAD in symptomatic patients, functional testing to detect coronary epicardial and microvascular dysfunction should be considered in those with INOCA who have persistent angina. Current diagnostic methods to clarify functional abnormalities and treatment strategies for epicardial and/or microvascular dysfunction in INOCA are reviewed.

Management of ischaemia with non-obstructive coronary arteries (INOCA)

Up to half of patients undergoing elective coronary angiography for the investigation of chest pain do not present with evidence of obstructive coronary artery disease. These patients are often discharged with a diagnosis of non-cardiac chest pain, yet many could have an ischaemic basis for their symptoms. This type of ischaemic chest pain in the absence of obstructive coronary artery disease is referred to as INOCA (ischaemia with non-obstructive coronary arteries). This comprehensive review of INOCA management looks at why these patients require treatment, who requires treatment based on diagnostic evaluation, what clinical treatment targets should be considered, how to treat patients using a personalised medicine approach, when to initiate treatment, and where future research is progressing.

Medium-term Effects of Enhanced External Counterpulsation in the Structural and Functional Parameters of Blood Vessels in Patients with Coronary Artery Disease

Aim. To study the mid-term effects of enhanced external counterpulsation (EECP) in the structural and functional parameters of blood vessels, exercise tolerance and quality of life indicators in patients with verified coronary artery disease (CAD).

Material and methods. Patients (n=70) with verified stable CAD (angina pectoris class II-III) complicated by chronic heart faillure class II-III (NYHA) were included in the study. Data from 65 patients (48 to 74 years old; 45 men and 20 women) are included in the final analysis. All patients had a course of EECP (35 hours procedures with a compression pressure of 220-280 mm Hg). All patients at baseline, 3 and 6 months later had a 6 walk minute test (6WMT), an assessment of the clinical status, quality of life of patients (Minnesota Living with Heart Failure Questionnaire, SF-36). Computer nailfold video capillaroscopy, photoplethysmography with pulse wave recording and contour analysis, applanation tonometry to assess central aortic systolic pressure and radial augmentation index were performed to assess the structural and functional state of large and microcirculatory vessels.

Results. Significant improvement in exercise tolerance both after 3 and after 6 months (increase in distance in 6WMT by 44.6% after 3 months and 34.3% after 6 months, p <0.05), improved quality of life (increased overall score on the SF-36 questionnaire from 50.3±8.1 to 59.8±8.8, p<0.05), an increase in the left ventricular ejection fraction were found. Significant improvement in indicators showing the function of the endothelium of both large vessels (phase shift: from 5.6 [2.45; 7.3] to 6.8 [3.1; 8.1] m / s) and microcirculatory vessels (occlusion index: from 1.51 [1.21; 1.7] to 1.66 [1.2; 1.9]), as well as a decrease in functional disorders of the capillary bed of the skin (% of perfused capillaries, density of the capillary network in the test with reactive hyperemia) were found after 3 months. However, after 6 months, there were no significant changes in these parameters compared to the baseline value. No significant change in indicators showing structural remodeling of both large vessels and microcirculatory vessels was found.

Conclusion. The positive effect of the EECP course on the functional status (exercise tolerance) and quality of life in patients with stable coronary artery disease complicated by chronic heart faillure was found both after 3 and 6 months. Positive dynamics of the functional state of large vessels and microvasculature was found only after 3 months.

The Use of Enhanced External Counterpulsation in the Treatment of Patients with Coronary Artery Disease

Enhanced external counterpulsation (EECP) is one of the most effective and safe non-invasive methods of treatment for patients with coronary artery disease (CAD), including complicated chronic heart failure (CHF). This method of therapeutic neoangiogenesis, used in conjunction with traditional drug therapy and myocardial revascularization, can significantly improve the quality of management of these patients.

Aim. To study the effect of the EECP course on exercise tolerance, quality of life, structural and functional parameters of blood vessels in patients with verified stable CAD complicated by CHF.

Material and methods. Patients (n=70) with verified stable CAD (angina pectoris class II-III) complicated by CHF class II-III (NYHA) were included in non-randomized uncontrolled study. Data from 67 patients (48 to 74 years old; 47 men and 20 women) were included in the final analysis. All patients had a course of EECP (35 one-hour procedures with a compression pressure of 220-280 mm Hg). All patients initially and 1.5 months after the EECP course had a 6-minute walk test (6MWT), an assessment of the clinical status, quality of life of patients (MLHFQ; Minnesota Living with Heart Failure Questionnaire). Computer nailfold video capillaroscopy, photoplethysmography with pulse wave recording and contour analysis, applanation tonometry to assess central aortic systolic pressure and radial augmentation index (RAI) were performed to assess the structural and functional state of large and microcirculatory vessels.

Results. A statistically significant improvement in exercise tolerance (increase in distance in 6MWT from 212 [189; 273] to 308 [251; 336] m), improvement in the clinical status of patients (decrease in points on the rating scale of clinical state from 6.5±1.8 to 4.4±1,2), improvement in the quality of life according to the MLHFQ questionnaire (from 51.9±6.2 to 38.6±7.1), increase in the left ventricle ejection fraction (from 41.6 [36.6;47.1] to 44.8 [39.5;50.7]%) were found. A statistically significant improvement in endothelial function indices of both large vessels (phase shift: from 5.6 [2.4;7.2] to 6.8 [3.3;8] m/s) and microcirculatory vessels (occlusion index: from 1.5 [1.2;1.7] to 1.66 [1.3;1.9]), as well as a decrease in functional disorders of nailfold capillaries (percent of perfused capillaries, capillary network density in the reactive hyperemia test) also were found. But no statistically significant changes in the structural remodeling indices of both large and microcirculatory vessels were found.

Conclusion. A positive effect of the EECP course both on the functional status with an increase in exercise tolerance and improvement in the quality of life, and on the functional state of large vessels and microvasculature was found in patients with stable CAD complicated by CHF.

Non-pharmacological Treatment of Refractory Angina and Microvascular Angina

Refractory angina (RA) is defined as debilitating anginal symptoms despite the optimal guideline-directed combination of medical, percutaneous, and surgical therapies. Often referred to as “no option”, these patients represent a significant unmet clinical need for healthcare institutions. Due to the ageing of the population, and increased survival from coronary artery disease, the number of patients with RA is expected to rise exponentially. Despite the developments of novel technologies for the treatment of RA, none of them found wide clinical application (to date). Microvascular dysfunction, alone or in combination with epicardial coronary disease, is thought to contribute significantly to refractory angina. However, most of the techniques developed to improve RA symptoms have not been tested specifically on patients with microvascular dysfunction. This review discusses the recent developments in the treatment of RA, and gives some perspectives on the future of these techniques.

Evaluation of enhanced external counterpulsation therapy for nonarteritic anterior ischemic optic neuropathy

Background

To explore the effects of enhanced external counterpulsation (EECP) and its underlying influencing factors in nonarteritic anterior ischemic optic neuropathy (NAION) patients.

Methods

Patients at Zhongshan Ophthalmic Center with recent-onset (< 8 weeks) NAION were retrospectively recruited. The patients had decided whether or not they would undergo EECP treatment, and the patients who declined were included in the control group. The effectiveness of EECP was evaluated by comparing the visual function and fellow eye involvement in patients with and without EECP treatment.

Results

In total, 61 patients (76 eyes) were included. Twenty-nine patients (37 eyes) underwent EECP treatment, while 32 patients (39 eyes) were included in the control group. Mean time from NAION onset to EECP initiation was 27.59 ± 16.70 days. In the EECP group, the mean EECP duration was 31.57 ± 18.45 days. EECP was well tolerated by all patients. However, there was no significant difference in visual function between the EECP and control groups. Furthermore, there was no evidence of the effectiveness of EECP in the subgroup analysis of patients with different systemic health conditions. Among the 42 patients with monocular NAION, the sequential attack rate was comparable between the EECP (27.78%) and control (25.00%) groups.

Conclusion

This study is the first nonrandomized controlled study to evaluate the effectiveness of EECP in NAION patients. Unfortunately, we failed to demonstrate the effectiveness of EECP in NAION at the 6-month follow-up. Any further application of EECP in NAION patients should be cautious.

Expert consensus on the clinical application of enhanced external counterpulsation in elderly people (2019)

Enhanced external counterpulsation (EECP) is a non-invasive assisted circulation technique and a rich pool of evidence has accumulated for its clinical application in the prevention and management of multiple comorbidities in the elderly population, including angina, heart failure, ischemic cerebrovascular diseases, neurodegenerative diseases, sleep disorder, diabetes and its complications, ischemic eye diseases, sudden hearing loss and erectile dysfunction, as well as various psychological and psychiatric conditions. When applying EECP to elderly patients, emphasis should be placed on issues such as safety assessment, risk management and protocol individualization, as well as the monitoring of efficacy during and after treatment.

[The implementation of the method of enhanced external counter pulsation for the treatment of cardiovascular diseases]

The cardiovascular diseases occupy a leading place in the structure of overall morbidity affecting the population not only of Russia but also of the majority of the developed countries throughout the world; they thus impose the heavy social and economic burden on both the public healthcare services and the modern society in general. At the same time, systemic atherosclerosis is considered to be one of the most common, severe, and life-threatening condition. Despite the presence of a large number of pharmaceutical and surgical methods for the treatment of this pathology, they are not infrequently lacking the desired effectiveness. The use of the shunting operations and endovascular methods failed to radically resolve the problem of managing systemic atherosclerosis and atherosclerosis of the lower limbs. A relatively novel approach which currently begins to find the ever increasing application for the treatment of patients presenting with cardiovascular pathology is based on the enhanced external counter-pulsation method although both the clinical and theoretical prerequisites of its application were developed rather long ago. This non-invasive therapeutic method allows to increase the perfusion pressure in the coronary arteries in diastole and to reduce the resistance to the cardiac ejection in the systole. The objective of this review article was to perform the analysis of the available literature publications on the use of the enhanced external counter-pulsation technique for the treatment of the patients presenting with the diseases of the cardiovascular system and to evaluate the clinical effectiveness of this approach as well as the availability of the treatment for the patients.

Coronary microvascular dysfunction in diabetes mellitus

The significance, mechanisms and consequences of coronary microvascular dysfunction associated with diabetes mellitus are topics into which we have insufficient insight at this time. It is widely recognized that endothelial dysfunction that is caused by diabetes in various vascular beds contributes to a wide range of complications and exerts unfavorable effects on microcirculatory regulation. The coronary microcirculation is precisely regulated through a number of interconnected physiological processes with the purpose of matching local blood flow to myocardial metabolic demands. Dysregulation of this network might contribute to varying degrees of pathological consequences. This review discusses the most important findings regarding coronary microvascular dysfunction in diabetes from pre-clinical and clinical perspectives.

Vessel heterogeneity of TIMI frame count and its relation to P-wave dispersion in patients with coronary slow flow

BACKGROUND

The vessel heterogeneity of thrombolysis in myocardial infarction (TIMI) frame count (TFC) in patients with coronary slow flow (CSF) remains to be further evaluated, and the correlation between TFC heterogeneity and P-wave dispersion (PWD) has not been elucidated. We aim to investigate the vessel heterogeneity of TFC in coronary arteries, and its relation to PWD in patients with CSF and otherwise normal coronary arteries.

METHODS

We studied 72 patients with angiographically documented CSF and 66 age- and gender-matched control subjects. The coefficient of variation (CV) and mean TFC of the three vessels were calculated. P-wave duration and PWD were measured on the standard electrocardiograms (ECGs).

RESULTS

The mean TFC and CV were both significantly higher in CSF patients than in controls (P<0.001 for both comparisons). The maximum P-wave duration (Pmax) and PWD were found to be significantly higher in CSF patients than in controls (P<0.001 for both comparisons). In patients with CSF, both Pmax and PWD were mildly correlated to mean TFC (r=0.318, P=0.009; and r=0.307, P=0.010), and were more significantly correlated to CV (r=0.506, P<0.001; and r=0.579, P<0.001).

CONCLUSIONS

These data demonstrate that variability of TFC in three coronary arteries is increased in CSF patients, and that the vessel heterogeneity in coronary flow might be intimately associated with PWD.

Coronary microvascular dysfunction, microvascular angina, and treatment strategies

Angina without coronary artery disease (CAD) has substantial morbidity and is present in 10% to 30% of patients undergoing angiography. Coronary microvascular dysfunction (CMD) is present in 50% to 65% of these patients. The optimal treatment of this cohort is undefined. We performed a systematic review to evaluate treatment strategies for objectively-defined CMD in the absence of CAD. We included studies assessing therapy in human subjects with angina and coronary flow reserve or myocardial perfusion reserve <2.5 by positron emission tomography, cardiac magnetic resonance imaging, dilution methods, or intracoronary Doppler in the absence of coronary artery stenosis ≥50% or structural heart disease. Only 8 papers met the strict inclusion criteria. The papers were heterogeneous, using different treatments, endpoints, and definitions of CMD. The small sample sizes severely limit the power of these studies, with an average of 11 patients per analysis. Studies evaluating sildenafil, quinapril, estrogen, and transcutaneous electrical nerve stimulation application demonstrated benefits in their respective endpoints. No benefit was found with L-arginine, doxazosin, pravastatin, and diltiazem. Our systematic review highlights that there is little data to support therapies for CMD. We assess the data meeting rigorous inclusion criteria and review the related but excluded published data. We additionally describe the next steps needed to address this research gap, including a standardized definition of CMD, routine assessment of CMD in studies of chest pain without obstructive CAD, and specific therapy assessment in the population with confirmed CMD.