Correlation of Non-Invasive Transthoracic Doppler Echocardiography with Invasive Doppler Wire-Derived Coronary Flow Reserve and Their Impact on Infarct Size in Patients with ST-Segment Elevation Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention.

Background: Coronary microvascular dysfunction is associated with adverse prognosis after ST-segment elevation myocardial infarction (STEMI). We aimed to compare the invasive, Doppler wire-based coronary flow reserve (CFR) with the non-invasive transthoracic Doppler echocardiography (TTDE)-derived CFR, and their ability to predict infarct size. Methods: We included 36 patients with invasive Doppler wire assessment on days 3-7 after STEMI treated with primary percutaneous coronary intervention (PCI), of which TTDE-derived CFR was measured in 47 vessels (29 patients) within 6 h of the invasive Doppler. Infarct size was assessed by cardiac magnetic resonance at a median of 8 months. Results: The correlation between invasive and non-invasive CFR was modest in the overall cohort (rho 0.400, p = 0.005). It improved when only measurements in the LAD artery were considered (rho 0.554, p = 0.002), with no significant correlation in the RCA artery (rho -0.190, p = 0.435). Both invasive (AUC 0.888) and non-invasive (AUC 0.868) CFR, measured in the recanalized culprit artery, showed a good ability to predict infarct sizes ≥18% of the left ventricular mass, with the optimal cut off values of 1.85 and 1.80, respectively. Conclusions: In patients with STEMI, TTDE- and Doppler wire-derived CFR exhibit significant correlation, when measured in the LAD artery, and both have a similarly strong association with the final infarct size.

Noninvasive evaluation of dynamic microvascular dysfunction in ischemia and no obstructive coronary artery disease patients with suspected vasospasm.

INTRODUCTION: In patients with ischemia and no obstructive coronary artery disease (INOCA), a dynamic coronary microvascular dysfunction (CMD) is frequent but difficult to capture by noninvasive means.The aim of our study was to assess dynamic CMD in INOCA patients with stress echocardiography after vasoconstrictive and vasodilator stimuli. METHODS: In this prospective single-center study, we have enrolled 40 INOCA patients (age 56.3 ±â€Š13 years, 32 women). All participants underwent stress echocardiography with hyperventilation (HYP), followed by supine bicycle exercise (HYP+EXE) and adenosine (ADO). Stress echocardiography included an assessment of regional wall motion abnormality (RWMA) and coronary flow velocity (CFV) in the distal left anterior descending (LAD) coronary artery. RESULTS: HYP induced a 30% increase in rate pressure product (rest = 10 244 ±â€Š2353 vs. HYP = 13 214 ±â€Š3266 mmHg x bpm, P  < 0.001) accompanied by a paradoxical reduction in CFV (HYP< rest) in 21 patients (52%). HYP alone was less effective than HYP+EXE in inducing anginal pain (6/40, 15% vs. 10/40, 25%, P  = 0.046), ST segment changes (6/40, 15% vs. 24/40, 60%, P  < 0.001), and RWMA (6/40, 15% vs. 13/40, 32.5%, P  = 0.008). ADO-induced vasodilation was preserved (≥2.0) in all patients. CONCLUSION: In patients with INOCA, a coronary vasoconstriction after HYP is common, in absence of structural CMD detectable with ADO. HYP+EXE test represents a more powerful ischemia inducer than HYP alone. Stress echocardiography with LAD-CFV may allow the noninvasive assessment of dynamic and structural coronary microcirculation during stress.

Prognostic Value of Mitral Regurgitation in Patients with Primary Hypertrophic Cardiomyopathy.

Background and Objectives: Mitral valve pathology and mitral regurgitation (MR) are very common in patients with hypertrophic cardiomyopathy (HCM), and the evaluation of mitral valve anatomy and degree of MR is important in patients with HCM. The aim of our study was to examine the potential influence of moderate or moderately severe MR on the prognosis, clinical presentation, and structural characteristics of HCM patients. Materials and Methods: A prospective study examined 176 patients diagnosed with primary asymmetric HCM. According to the severity of the MR, the patients were divided into two groups: Group 1 (n = 116) with no/trace or mild MR and Group 2 (n = 60) with moderate or moderately severe MR. All patients had clinical and echocardiographic examinations, as well as a 24 h Holter ECG. Results: Group 2 had significantly more often the presence of the obstructive type of HCM (p < 0.001), syncope (p = 0.030), NYHA II class (p < 0.001), and atrial fibrillation (p = 0.023). Also, Group 2 had an enlarged left atrial dimension (p < 0.001), left atrial volume index (p < 0.001), and indirectly measured systolic pressure in the right ventricle (p < 0.001). Patients with a higher grade of MR had a significantly higher E/e' (p < 0.001) and, as a result, higher values of Nt pro BNP values (p < 0.001) compared to Group 1. Kaplan-Meier analysis demonstrated that the event-free survival rate during a median follow-up of 88 (IQR 40-112) months was significantly higher in Group 1 compared to Group 2 (84% vs. 45% at 8 years; log-rank 20.4, p < 0.001). After adjustment for relevant confounders, the presence of moderate or moderately severe MR remained as an independent predictor of adverse outcomes (HR 2.788; 95% CI 1.221-6.364, p = 0.015). Conclusions: The presence of moderate or moderately severe MR was associated with unfavorable long-term outcomes in HCM patients.

Predictors of diastolic deceleration time of coronary flow velocity of infarct related and reference coronary artery assessed by transthoracic Doppler echocardiography in the chronic phase of successfully reperfused anterior myocardial infarction: relation to infarct size.

Introduction: High-frequency transthoracic Doppler echocardiography (TDE) enables the assessment of flow velocity and velocity pattern in different coronary arteries, including the assessment of diastolic deceleration time (DDT) of coronary flow velocity. Short DDT of infarct related artery (IRA) (<600 msec) in the acute phase of anterior myocardial infarction (MI) is the predictor of adverse left ventricular (LV) remodeling and prognosis. The significance of DDT of coronary flow velocity assessment in the chronic phase of anterior MI is not well established. Our study aimed to establish the predictors of DDT of the coronary flow velocity of infarct related (left anterior descendent-DDT of LAD) and reference coronary artery, evaluated by TDE, and to assess their relation to infarct size in the chronic phase of successfully reperfused first anterior MI. Methods: Our study included 40 consecutive patients (34 men, mean age 52 ± 12 years) one month after the first anterior STEMI and single vessel disease successfully treated with primary PCI. All patients underwent SPECT MPI for the assessment of LV volumes, ejection fraction, and percentage of the myocardium with fixed perfusion abnormalities and echocardiographic examination including the evaluation of DDT of IRA and reference coronary artery TDE. Results: DDT of LAD correlated significantly to the WMSI (r = -0.467, p = 0.002), LV end-systolic volume (r = -0.412, p = 0.008), LV ejection fraction (r = 0.427, p = 0.006), while the strongest correlation was observed between DDT of LAD and the extent of fixed perfusion abnormality (r = -0.627, p < 0.0001), Multivariate analysis revealed percentage of fixed perfusion abnormalities along with DDT of reference coronary artery as the independent predictors of DDT of IRA. DDT of IRA shorter than 886 msec predicts large fixed perfusion abnormalities (>20%) with a sensitivity of 89% and specificity of 62% (AUC 0.842). Conclusion: DDT of LAD assessed by TDE in the chronic phase of successfully reperfused first anterior MI is a usefull variable for the assessment of microcirculatory function that exclusively reflects the extent of microvascular damage and relates to infarct size.

Heart Rate Recovery as a Predictor of Long-Term Adverse Events after Negative Exercise Testing in Patients with Chest Pain and Pre-Test Probability of Coronary Artery Disease from 15% to 65.

BACKGROUND: The prognosis of patients with chest pain after a negative exercise test is good, but some adverse events occur in this low-risk group. The aim of our study was to identify predictors of long-term adverse events after a negative exercise test in patients with chest pain and a lower intermediate (15-65%) pre-test probability of coronary artery disease (CAD) and to assess the prognostic value of exercise electrocardiography and exercise stress echocardiography in this group of patients. METHODS: We identified from our stress test laboratory database 862 patients with chest pain without previously known CAD and with a pre-test probability of CAD ranging from 15 to 65% (mean 41 ± 14%) who underwent exercise testing. Patients were followed for the occurrence of death, non-fatal myocardial infarction (MI) and clinically guided revascularization. RESULTS: During the median follow-up of 94 months, 87 patients (10.1%) had an adverse event (AE). A total of 30 patients died (3.5%), 23 patients suffered non-fatal MI (2.7%) and 34 patients (3.9%) had clinically guided revascularization (20 patients percutaneous and 14 patients surgical revascularizations). Male gender, age, the presence of diabetes and a slow heart rate recovery (HRR) in the first minute after exercise were independently related to the occurrence of AEs. Adverse events occurred in 10.3% of patients who were tested by exercise stress echocardiography and in 10.0% of those who underwent stress electrocardiography (p = 0.888). CONCLUSION: The risk of AEs after negative exercise testing in patients with a pre-test probability of CAD of 15-65% is low. Male patients with a history of diabetes and slow HRR in the first minute after exercise have an increased risk of an adverse outcome.

Role of different echocardiographic modalities in the assessment of microvascular function in women with ischemia and no obstructive coronary arteries.

This review summarizes current knowledge about echocardiographic modalities used to assess microvascular function and left ventricular (LV) systolic function in women with ischemia and no obstructive coronary arteries (INOCA). Although the entire pathophysiological background of this clinical entity still remains elusive, it is primarily linked to microvascular dysfunction which can be assessed by coronary flow velocity reserve. Subtle impairments of LV systolic function in women with INOCA are difficult to assess by interpretation of wall motion abnormalities. LV longitudinal function impairment is considered to be an early marker of subclinical systolic dysfunction and can be assessed by global longitudinal strain quantification.

Specific impact of cardiovascular risk factors on coronary microcirculation in patients with subclinical hypothyroidism.

Background: Although thyroid hormones have significant effect on cardiovascular system, the impact of subtle thyroid dysfunction such as subclinical hypothyroidism (SCH) remains to be determined. We investigated coronary flow reserve (CFR) in patients with subclinical hypothyroidism. Methods: Thirty two subjects with SCH and eighteen control subjects with normal serum thyroid hormones and thyroid-stimulating hormone (TSH) levels were included in the study. TSH, free thyroxine, free triiodothyronine, glucose, insulin, HbA1c, cholesterol, triglyceride and plasma levels of C-reactive protein were measured. Coronary diastolic peak flow velocities in left anterior descending coronary artery were measured at baseline and after adenosine infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocity. Results: CFR values were not significantly different between the two groups (SCH 2.76±0.35 vs controls 2.76±0.42). There was a significant correlation of CFR with waist to hip ratio, hypertension, smoking habits, markers of glucose status (glucose level, HbA1c, insulin level, HOMA IR), cholesterol, LDL-cholesterol and triglyceride levels in SCH group, whereas only cholesterol level showed significant correlation with CFR in controls. There was no correlation between CFR and thyroid hormones. Conclusions: We concluded that there is a different impact of cardiovascular risk factors on CFR in SCH patients compared to healthy control and that these two groups behave differently in the same circumstances under the same risk factors. The basis for this difference could be that the altered thyroid axis "set point" changes the sensitivity of the microvasculature in patients with SCH to known risk factors.

Prognostic Value of Transthoracic Doppler Echocardiography Coronary Flow Velocity Reserve in Patients With Asymmetric Hypertrophic Cardiomyopathy.

Background Microvascular dysfunction might be a major determinant of clinical deterioration and outcome in patients with hypertrophic cardiomyopathy (HCM). However, long-term prognostic value of transthoracic Doppler echocardiography (TDE) coronary flow velocity reserve (CFVR) on clinical outcome is uncertain in HCM patients. Therefore, the aim of our study was to assess long-term prognostic value of CFVR on clinical outcome in HCM population. Methods and Results We prospectively included 150 HCM patients (82 women; mean age 48±15 years). Patients' clinical characteristics, echocardiographic and CFVR findings (both for left anterior descending [LAD] and posterior descending artery [PD]), were assessed in all patients. The primary outcome was a composite of: HCM related death, heart failure requiring hospitalization, sustained ventricular tachycardia and ischemic stroke. Patients were stratified into 2 subgroups depending on CFVR LAD value: Group 1 (CFVR LAD>2, [n=87]) and Group 2 (CFVR LAD≤2, [n=63]). During a median follow-up of 88 months, 41/150 (27.3%) patients had adverse cardiac events. In Group 1, there were 8/87 (9.2%), whereas in Group 2 there were 33/63 (52.4%, P<0.001 vs. Group 1) adverse cardiac events. By Kaplan-Meier analysis, patients with preserved CFVR LAD had significantly higher cumulative event-free survival rate compared to patients with impaired CFVR LAD (96.4% and 90.9% versus 66.9% and 40.0%, at 5 and 8 years, respectively: log-rank 37.2, P<0.001). Multivariable analysis identified only CFVR LAD≤2 as an independent predictor for adverse cardiac outcome (HR 6.54; 95% CI 2.83-16.30, P<0.001), while CFVR PD was not significantly associated with outcome. Conclusions In patients with HCM, impaired CFVR LAD (≤2) is a strong, independent predictor of adverse cardiac outcome. When the aim of testing is HCM risk stratification and CFVR LAD data are available, the evaluation of CFVR PD is redundant.

Focal Myocarditis after Mild COVID-19 Infection in Athletes.

COVID-19 infection in athletes usually has a milder course, but in the case of complications, myocarditis and even sudden cardiac death may occur. We examined an athlete who felt symptoms upon returning to training after asymptomatic COVID-19 infection. Physical, laboratory, and echocardiography findings were normal. The cardiopulmonary exercise test was interrupted at submaximal effort due to severe dyspnea in the presence of reduced functional capacity in comparison to previous tests. Cardiac magnetic resonance (CMR) detected the focal myocarditis. After three months of recovery, CMR still revealed the presence of focal myocarditis and the persistence of decreased functional capacity. This case raises the question of screening athletes even after asymptomatic forms of COVID-19 infection.

Hemodynamic Heterogeneity of Reduced Cardiac Reserve Unmasked by Volumetric Exercise Echocardiography.

BACKGROUND: Two-dimensional volumetric exercise stress echocardiography (ESE) provides an integrated view of left ventricular (LV) preload reserve through end-diastolic volume (EDV) and LV contractile reserve (LVCR) through end-systolic volume (ESV) changes. PURPOSE: To assess the dependence of cardiac reserve upon LVCR, EDV, and heart rate (HR) during ESE. METHODS: We prospectively performed semi-supine bicycle or treadmill ESE in 1344 patients (age 59.8 ± 11.4 years; ejection fraction = 63 ± 8%) referred for known or suspected coronary artery disease. All patients had negative ESE by wall motion criteria. EDV and ESV were measured by biplane Simpson rule with 2-dimensional echocardiography. Cardiac index reserve was identified by peak-rest value. LVCR was the stress-rest ratio of force (systolic blood pressure by cuff sphygmomanometer/ESV, abnormal values ≤2.0). Preload reserve was defined by an increase in EDV. Cardiac index was calculated as stroke volume index * HR (by EKG). HR reserve (stress/rest ratio) <1.85 identified chronotropic incompetence. RESULTS: Of the 1344 patients, 448 were in the lowest tertile of cardiac index reserve with stress. Of them, 303 (67.6%) achieved HR reserve <1.85; 252 (56.3%) had an abnormal LVCR and 341 (76.1%) a reduction of preload reserve, with 446 patients (99.6%) showing ≥1 abnormality. At binary logistic regression analysis, reduced preload reserve (odds ratio [OR]: 5.610; 95% confidence intervals [CI]: 4.025 to 7.821), chronotropic incompetence (OR: 3.923, 95% CI: 2.915 to 5.279), and abnormal LVCR (OR: 1.579; 95% CI: 1.105 to 2.259) were independently associated with lowest tertile of cardiac index reserve at peak stress. CONCLUSIONS: Heart rate assessment and volumetric echocardiography during ESE identify the heterogeneity of hemodynamic phenotypes of impaired chronotropic, preload or LVCR underlying a reduced cardiac reserve.

Functional Assessment of Myocardial Bridging With Conventional and Diastolic Fractional Flow Reserve: Vasodilator Versus Inotropic Provocation.

Background Functional assessment of myocardial bridging (MB) remains clinically challenging because of the dynamic nature of the extravascular coronary compression with a certain degree of intraluminal coronary reduction. The aim of our study was to assess performance and diagnostic value of diastolic-fractional flow reserve (d-FFR) during dobutamine provocation versus conventional-FFR during adenosine provocation with exercise-induced myocardial ischemia as reference. Methods and Results This prospective study includes 60 symptomatic patients (45 men, mean age 57±9 years) with MB on the left anterior descending artery and systolic compression ≥50% diameter stenosis. Patients were evaluated by exercise stress-echocardiography test, and both conventional-FFR and d-FFR in the distal segment of left anterior descending artery during intravenous infusion of adenosine (140 µg/kg per minute) and dobutamine (10-50 µg/kg per minute), separately. Exercise-stress-echocardiography test was positive for myocardial ischemia in 19/60 patients (32%). Conventional-FFR during adenosine and peak dobutamine had similar values (0.84±0.04 versus 0.84±0.06, P=0.852), but d-FFR during peak dobutamine was significantly lower than d-FFR during adenosine (0.76±0.08 versus 0.79±0.08, P=0.018). Diastolic-FFR during peak dobutamine was significantly lower in the exercise-stress-echocardiography test -positive group compared with the exercise- stress-echocardiography test -negative group (0.70±0.07 versus 0.79±0.06, P<0.001), but not during adenosine (0.79±0.07 versus 0.78±0.09, P=0.613). Among physiological indices, d-FFR during peak dobutamine was the only independent predictor of functionally significant MB (odds ratio, 0.870; 95% CI, 0.767-0.986, P=0.03). Receiver-operating characteristics curve analysis identifies the optimal d-FFR during peak dobutamine cut-off ≤0.76 (area under curve, 0.927; 95% CI, 0.833-1.000; P<0.001) with a sensitivity, specificity, and positive and negative predictive value of 95%, 95%, 90%, and 98%, respectively, for identifying MB associated with stress-induced ischemia. Conclusions Diastolic-FFR, but not conventional-FFR, during inotropic stimulation with high-dose dobutamine, in comparison to vasodilatation with adenosine, provides more reliable functional significance of MB in relation to stress-induced myocardial ischemia.

The Coronary ARteriogenesis with combined Heparin and EXercise therapy in chronic refractory Angina (CARHEXA) trial: A double-blind, randomized, placebo-controlled stress echocardiographic study.

BACKGROUND: Coronary collateral circulation exerts protective effects on myocardial ischaemia due to coronary artery disease and can be promoted by exercise with heparin co-administration. Whether this arteriogenetic effect is accompanied by functional improvement of left ventricle during stress and lessening of angina symptoms remains unknown. AIMS: To evaluate the anti-ischaemic efficacy of heparin plus exercise in coronary artery disease. METHODS: In a prospective, single-centre, randomized, double-blind study we recruited 32 'no-option' patients (27 males; mean age 61 ± 8 years) with stable angina, exercise-induced ischaemia and coronary artery disease not suitable for revascularization. All underwent a two-week cycle of exercise (two exercise sessions per day, five days per week) and were randomized (n = 16 per group) to intravenous placebo (0.9% saline) versus unfractionated heparin (5.000 IU intravenously), 10 min prior to exercise. We assessed Canadian Cardiovascular Society angina class, stress electrocardiogram and echo parameters (wall motion score index) and computed tomography angiography for collaterals. RESULTS: After two-week cycle, Canadian Cardiovascular Society class statistically decreased in both groups (heparin plus exercise group: 2.6 ± 0.7 to 1.9 ± 0.7, p < 0.001, exercise group: 2.4 ± 0.7 to 2.1 ± 0.9, p = 0.046). Only the heparin plus exercise group improved time-to-ST segment depression (before 270, 228-327 s vs. after 339, 280-360 s, p = 0.012) and wall motion score index (before 1.38 ± 0.25 vs. after 1.28 ± 0.18, p = 0.005). By multi-slice computed tomography angiography, collaterals improved in 12/15 (80%) in the heparin plus exercise group versus 2/16 (12.5%) in the exercise group (p < 0.001). CONCLUSION: A two-week, 10-test cycle of heparin plus exercise is better than exercise in improving angina class, myocardial ischaemia and collaterals by computed tomography angiography.

Coronary Flow Velocity Reserve Using Dobutamine Test for Noninvasive Functional Assessment of Myocardial Bridging.

BACKGROUND: It has been shown that coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) during dobutamine (DOB) provocation provides a more accurate functional evaluation of myocardial bridging (MB) compared to adenosine. However; the cut-off value of CFVR during DOB for identification of MB associated with myocardial ischemia has not been fully clarified. PURPOSE: This prospective study aimed to determine the cut-off value of TTDE-CFVR during DOB in patients with isolated-MB, as compared with stress-induced wall motion abnormalities (VMA) during exercise stress-echocardiography (SE) as reference. METHODS: Eighty-one symptomatic patients (55 males [68%], mean age 56 ± 10 years; range: 27-74 years) with the existence of isolated-MB on the left anterior descending artery (LAD) and systolic MB-compression ≥50% diameter stenosis (DS) were eligible to participate in the study. Each patient underwent treadmill exercise-SE, invasive coronary angiography, and TTDE-CFVR measurements in the distal segment of LAD during DOB infusion (DOB: 10-40 µg/kg/min). Using quantitative coronary angiography, both minimal luminal diameter (MLD) and percent DS at MB-site at end-systole and end-diastole were determined. RESULTS: Stress-induced myocardial ischemia with the occurrence of WMA was found in 23 patients (28%). CFVR during peak DOB was significantly lower in the SE-positive group compared with the SE-negative group (1.94 ± 0.16 vs. 2.78 ± 0.53; p < 0.001). ROC analyses identified the optimal CFVR cut-off value ≤ 2.1 obtained during high-dose dobutamine (>20 µg/kg/min) for the identification of MB associated with stress-induced WMA, with a sensitivity, specificity, positive and negative predictive value of 96%, 95%, 88%, and 98%, respectively (AUC 0.986; 95% CI: 0.967-1.000; p < 0.001). Multivariate logistic regression analysis revealed that MLD and percent DS, both at end-diastole, were the only independent predictors of ischemic CFVR values ≤2.1 (OR: 0.023; 95% CI: 0.001-0.534; p = 0.019; OR: 1.147; 95% CI: 1.042-1.263; p = 0.005; respectively). CONCLUSIONS: Noninvasive CFVR during dobutamine provocation appears to be an additional and important noninvasive tool to determine the functional severity of isolated-MB. A transthoracic CFVR cut-off ≤2.1 measured at a high-dobutamine dose may be adequate for detecting myocardial ischemia in patients with isolated-MB.

The Value of Stress Echocardiography Imaging and Functional Parameters in Patients with aVR Lead ST-Segment Elevation during an Exercise Stress Test to Detect Significant Left Main Stenosis.

OBJECTIVE: To evaluate the role of functional and imaging parameters during exercise stress echocardiography (SE) in the presence of ST-segment elevation (ST-E) in aVR leads to predict significant left main/left main equivalent/or ostial left anterior descending (LAD) stenosis (LM+). METHODS: The study population included 548 patients with ECG and echo markers of myocardial ischemia, in whom diagnostic coronary angiography was performed. We analyzed the patients' clinical characteristics, ECG changes, wall motion score index (WMSI) by stress echocardiography (SE), as well as functional capacity during exercise (METs) and Duke treadmill score. RESULTS: aVR ST-segment elevation was found in 60/548 (11%) patients, whereas aVR ST-E was found in 23/57 patients with left main LM stenosis (Sn 40%, Sp 92%, PPV 38%, NPV 93%). When aVR ST-E was combined with other functional/imaging parameters, patients with aVR ST-E and LM+ had significantly worse functional capacity in METs (5.0±2.2 vs. 6.7±2.3, P=0.005), lower Duke score (-6.8±6.8 vs. -3.6±4.1, P=0.049), and higher deterioration of WMSI (0.51±0.24 vs. 0.39±0.24, P=0.046). Significant multivariable predictors of the left main (LM) stenosis were aVR ST-E and positive SE in LAD territory in the whole group of patients, and Delta WMSI, Duke score and METs achieved in patients presented with aVR ST-E during exercise. CONCLUSION: The aVR ST-segment alone has intermediate sensitivity in detecting significant LM stenosis in patients referred to SE testing for chest pain. When combined with other functional and imaging parameters, including poor exercise functional capacity in METs, lower Duke score or greater WMA in the territory of LAD, its diagnostic power to detect LM significantly increases.

Prompt and consistent improvement of coronary flow velocity reserve following successful recanalization of the coronary chronic total occlusion in patients with viable myocardium.

BACKGROUND: Coronary chronic total occlusion (CTO) is characterized by the presence of collateral blood vessels which can provide additional blood supply to CTO-artery dependent myocardium. Successful CTO recanalization is followed by significant decrease in collateral donor artery blood flow and collateral derecruitment, but data on coronary hemodynamic changes in relation to myocardial function are limited. We assessed changes in coronary flow velocity reserve (CFVR) by echocardiography in collateral donor and recanalized artery following successful opening of coronary CTO. METHODS: Our study enrolled 31 patients (60 ± 9 years; 22 male) with CTO and viable myocardium by SPECT scheduled for percutaneous coronary intervention (PCI). Non-invasive CFVR was measured in collateral donor artery before PCI, 24 h and 6 months post-PCI, and 24 h and 6 months in recanalized artery following successful PCI of CTO. RESULTS: Collateral donor artery showed significant increase in CFVR 24 h after CTO recanalization compared to pre-PCI values (2.30 ± 0.49 vs. 2.71 ± 0.45, p = 0.005), which remained unchanged after 6-months (2.68 ± 0.24). Baseline blood flow velocity of the collateral donor artery significantly decreased 24 h post-PCI compared to pre-PCI (0.28 ± 0.06 vs. 0.24 ± 0.04 m/s), and remained similar after 6 months, with no significant difference in maximum hyperemic blood flow velocity pre-PCI, 24 h and 6 months post-PCI. CFVR of the recanalized coronary artery 24 h post-PCI was 2.55 ± 0.35, and remained similar 6 months later (2.62 ± 0.26, p = NS). CONCLUSIONS: In patients with viable myocardium, prompt and significant CFVR increase in both recanalized and collateral donor artery, was observed within 24 h after successful recanalization of CTO artery, which maintained constant during the 6 months. TRIAL REGISTRATION: ClinicalTrials.gov (Number NCT04060615 ).

Impairment of coronary flow velocity reserve and global longitudinal strain in women with cardiac syndrome X and slow coronary flow.

BACKGROUND: Microvascular dysfunction (MVD) is associated with adverse prognosis and may account for abnormal stress tests and angina symptoms in women with cardiac syndrome X (CSX). The aim of our study was to assess MVD by coronary flow velocity reserve (CFVR) and left ventricular (LV) contractile function by LV global longitudinal strain (LVGLS) in CSX patients with respect to presence of slow coronary flow (SCF). It was of additional importance to evaluate clinical status of CSX patients using Seattle Angina Questionnaire. METHODS AND RESULTS: Study population included 70 women with CSX (mean age 61 ± 7 years) and 34 age-matched controls. CSX group was stratified into two subgroups depending on SCF presence: CSX-Thrombolysis In Myocardial Infarction (TIMI) 3- normal flow subgroup (n = 38) and CSX-TIMI 2- SCF subgroup (n = 32) as defined by coronary angiography. LVGLS measurements and CFVR of left anterior descending (LAD) and posterior descending (PD) artery were performed. CFVR-LAD and PD were markedly impaired in CSX group compared to controls (2.34 ± 0.25 vs 3.05 ± 0.21, p < 0.001; 2.32 ± 0.24 vs 3.01 ± 0.13, p < 0.001), and furthermore decreased in CSX-TIMI 2 patients. Resting, peak, and ΔLVGLS were all significantly impaired in CSX group compared to controls (for all p < 0.001), and furthermore reduced in CSX-TIMI 2 subgroup. Strongest correlation was found between peak LVGLS and CFVR LAD (r = -0.784, p < 0.001) and PD (r = -0.772, p < 0.001). CSX-TIMI 2 subgroup had more frequent angina symptoms and more impaired quality of life. CONCLUSIONS: MVD in CSX patients is demonstrated by reduction in CFVR and LVGLS values. SCF implies more profound impairment of microvascular and LV systolic function along with worse clinical presentation.

Nature of Cardiac Rehabilitation Around the Globe.

BACKGROUND: Cardiac rehabilitation (CR) is a clinically-effective but complex model of care. The purpose of this study was to characterize the nature of CR programs around the world, in relation to guideline recommendations, and compare this by World Health Organization (WHO) region. METHODS: In this cross-sectional study, a piloted survey was administered online to CR programs globally. Cardiac associations and local champions facilitated program identification. Quality (benchmark of ≥ 75% of programs in a given country meeting each of 20 indicators) was ranked. Results were compared by WHO region using generalized linear mixed models. FINDINGS: 111/203 (54.7%) countries in the world offer CR; data were collected in 93 (83.8%; N = 1082 surveys, 32.1% program response rate). The most commonly-accepted indications were: myocardial infarction (n = 832, 97.4%), percutaneous coronary intervention (n = 820, 96.1%; 0.10), and coronary artery bypass surgery (n = 817, 95.8%). Most programs were led by physicians (n = 680; 69.1%). The most common CR providers (mean = 5.9 ±â€¯2.8/program) were: nurses (n = 816, 88.1%; low in Africa, p < 0.001), dietitians (n = 739, 80.2%), and physiotherapists (n = 733, 79.3%). The most commonly-offered core components (mean = 8.7 ±â€¯1.9 program) were: initial assessment (n = 939, 98.8%; most commonly for hypertension, tobacco, and physical inactivity), risk factor management (n = 928, 98.2%), patient education (n = 895, 96.9%), and exercise (n = 898, 94.3%; lower in Western Pacific, p < 0.01). All regions met ≥ 16/20 quality indicators, but quality was < 75% for tobacco cessation and return-to-work counseling (lower in Americas, p = < 0.05). INTERPRETATION: This first-ever survey of CR around the globe suggests CR quality is high. However, there is significant regional variation, which could impact patient outcomes.

Cardiac Rehabilitation Availability and Density around the Globe.

BACKGROUND: Despite the epidemic of cardiovascular disease and the benefits of cardiac rehabilitation (CR), availability is known to be insufficient, although this is not quantified. This study ascertained CR availability, volumes and its drivers, and density. METHODS: A survey was administered to CR programs globally. Cardiac associations and local champions facilitated program identification. Factors associated with volumes were assessed using generalized linear mixed models, and compared by World Health Organization region. Density (i.e. annual ischemic heart disease [IHD] incidence estimate from Global Burden of Disease study divided by national CR capacity) was computed. FINDINGS: CR was available in 111/203 (54.7%) countries; data were collected in 93 (83.8% country response; N = 1082 surveys, 32.1% program response rate). Availability by region ranged from 80.7% of countries in Europe, to 17.0% in Africa (p < .001). There were 5753 programs globally that could serve 1,655,083 patients/year, despite an estimated 20,279,651 incident IHD cases globally/year. Volume was significantly greater where patients were systematically referred (odds ratio [OR] = 1.36, 95% confidence interval [CI] = 1.35-1.38) and programs offered alternative models (OR = 1.05, 95%CI = 1.04-1.06), and significantly lower with private (OR = .92, 95%CI = .91-.93) or public (OR = .83, 95%CI = .82-84) funding compared to hybrid sources.Median capacity (i.e., number of patients a program could serve annually) was 246/program (Q25-Q75 = 150-390). The absolute density was one CR spot per 11 IHD cases in countries with CR, and 12 globally. INTERPRETATION: CR is available in only half of countries globally. Where offered, capacity is grossly insufficient, such that most patients will not derive the benefits associated with participation.

Cardiac rehabilitation availability and delivery in Europe: How does it differ by region and compare with other high-income countries?: Endorsed by the European Association of Preventive Cardiology.

AIMS: The aims of this study were to establish cardiac rehabilitation availability and density, as well as the nature of programmes, and to compare these by European region (geoscheme) and with other high-income countries. METHODS: A survey was administered to cardiac rehabilitation programmes globally. Cardiac associations were engaged to facilitate programme identification. Density was computed using global burden of disease study ischaemic heart disease incidence estimates. Four high-income countries were selected for comparison (N = 790 programmes) to European data, and multilevel analyses were performed. RESULTS: Cardiac rehabilitation was available in 40/44 (90.9%) European countries. Data were collected in 37 (94.8% country response rate). A total of 455/1538 (29.6% response rate) programme respondents initiated the survey. Programme volumes (median 300) were greatest in western European countries, but overall were higher than in other high-income countries (P < 0.001). Across all Europe, there was on average only 1 CR spot per 7 IHD patients, with an unmet regional need of 3,449,460 spots annually. Most programmes were funded by social security (n = 25, 59.5%; with significant regional variation, P < 0.001), but in 72 (16.0%) patients paid some or all of the programme costs (or ∼18.5% of the ∼€150.0/programme) out of pocket. Guideline-indicated conditions were accepted in 70% or more of programmes (lower for stable coronary disease), with no regional variation. Programmes had a multidisciplinary team of 6.5 ± 3.0 staff (number and type varied regionally; and European programmes had more staff than other high-income countries), offering 8.5 ± 1.5/10 core components (consistent with other high-income countries) over 24.8 ± 26.0 hours (regional differences, P < 0.05). CONCLUSION: European cardiac rehabilitation capacity must be augmented. Where available, services were consistent with guidelines, but varied regionally.

Prognostic Value of Preserved Coronary Flow Velocity Reserve by Noninvasive Transthoracic Doppler Echocardiography in Patients With Angiographically Intermediate Left Main Stenosis.

BACKGROUND: The potential of angiography to evaluate the hemodynamic severity of a left main coronary artery (LM) stenosis is limited. Noninvasive transthoracic Doppler echocardiographic coronary flow velocity reserve (CFVR) evaluation of intermediate coronary stenosis has demonstrated remarkably high negative prognostic value. The aim of this study was to assess clinical outcomes in patients with angiographically intermediate LM stenosis and preserved CFVR (>2.0) as evaluated by transthoracic Doppler echocardiographic CFVR. METHODS: The initial study population included 102 patients with intermediate coronary stenosis of the LM referred for transthoracic Doppler echocardiographic CFVR assessment. Peak diastolic CFVR measurements were performed in the distal segment of the left anterior descending coronary artery after intravenous adenosine (140 µg/kg/min), and CFVR was calculated as the ratio between maximal hyperemic and baseline coronary flow velocity. Nineteen patients had impaired CFVR (≤2.0) and were excluded from further analysis, as well as two patients with poor acoustic windows. The final group consisted of 81 patients (mean age, 60 ± 9 years; 76 men) evaluated for adverse cardiac events including death, myocardial infarction, and revascularization. RESULTS: Mean follow-up duration was 62 ± 26 months. Mean CFVR was 2.4 ± 0.4. Total event-free survival was 75 of 81 (92.6%), as six patients were referred for revascularization (five patients with coronary artery bypass grafting, one patient with percutaneous coronary intervention). There were no documented myocardial infarctions or cardiovascular deaths in the follow-up period. CONCLUSIONS: In patients with angiographically intermediate and equivocal LM stenosis and preserved CFVR values of >2.0, revascularization can be safely deferred.