Effectiveness of an Interactive mHealth App (EVITE) in Improving Lifestyle After a Coronary Event: Randomized Controlled Trial.

BACKGROUND: Coronary heart disease is one of the leading causes of mortality worldwide. Secondary prevention is essential, as it reduces the risk of further coronary events. Mobile health (mHealth) technology could become a useful tool to improve lifestyles. OBJECTIVE: This study aimed to evaluate the effect of an mHealth intervention on people with coronary heart disease who received percutaneous coronary intervention. Improvements in lifestyle regarding diet, physical activity, and smoking; level of knowledge of a healthy lifestyle and the control of cardiovascular risk factors (CVRFs); and therapeutic adherence and quality of life were analyzed. METHODS: This was a randomized controlled trial with a parallel group design assigned 1:1 to either an intervention involving a smartphone app (mHealth group) or to standard health care (control group). The app was used for setting aims, the self-monitoring of lifestyle and CVRFs using measurements and records, educating people with access to information on their screens about healthy lifestyles and adhering to treatment, and giving motivation through feedback about achievements and aspects to improve. Both groups were assessed after 9 months. The primary outcome variables were adherence to the Mediterranean diet, frequency of food consumed, patient-reported physical activity, smoking, knowledge of healthy lifestyles and the control of CVRFs, adherence to treatment, quality of life, well-being, and satisfaction. RESULTS: The study analyzed 128 patients, 67 in the mHealth group and 61 in the control group; most were male (92/128, 71.9%), with a mean age of 59.49 (SD 8.97) years. Significant improvements were observed in the mHealth group compared with the control group regarding adherence to the Mediterranean diet (mean 11.83, SD 1.74 points vs mean 10.14, SD 2.02 points; P<.001), frequency of food consumption, patient-reported physical activity (mean 619.14, SD 318.21 min/week vs mean 471.70, SD 261.43 min/week; P=.007), giving up smoking (25/67, 75% vs 11/61, 42%; P=.01), level of knowledge of healthy lifestyles and the control of CVRFs (mean 118.70, SD 2.65 points vs mean 111.25, SD 9.05 points; P<.001), and the physical component of the quality of life 12-item Short Form survey (SF-12; mean 45.80, SD 10.79 points vs mean 41.40, SD 10.78 points; P=.02). Overall satisfaction was higher in the mHealth group (mean 48.22, SD 3.89 vs mean 46.00, SD 4.82 points; P=.002) and app satisfaction and usability were high (mean 44.38, SD 6.18 out of 50 points and mean 95.22, SD 7.37 out of 100). CONCLUSIONS: The EVITE app was effective in improving the lifestyle of patients in terms of adherence to the Mediterranean diet, frequency of healthy food consumption, physical activity, giving up smoking, knowledge of healthy lifestyles and controlling CVRFs, quality of life, and overall satisfaction. The app satisfaction and usability were excellent. TRIAL REGISTRATION: Clinicaltrials.gov NCT04118504; https://clinicaltrials.gov/study/NCT04118504.

Impact of mHealth application on adherence to cardiac rehabilitation guidelines after a coronary event: Randomised controlled clinical trial protocol.

Background: Coronary disease is the main cause of death around the world. mHealth technology is considered attractive and promising to promote behavioural changes aimed at healthy lifestyle habits among coronary patients. The purpose of this study is to evaluate the efficacy of an mHealth intervention regarding improved results in secondary prevention in patients after an acute myocardial infarction (AMI) or angina in terms of lifestyle, clinical variables and therapeutic compliance. Methods: Randomised clinical trial with 300 patients who underwent a percutaneous coronary intervention (PCI) with stent implant. They will be assigned to either the mHealth group, subject to a self-monitored educational intervention involving an internet application installed on their mobile phone or tablet, or to a control group receiving standard healthcare (150 patients in each arm). The primary outcome variables will be adherence to the Mediterranean diet, physical activity, smoking, therapeutic compliance, knowledge acquired, user-friendliness and satisfaction with the application. Measurements of blood pressure, heart rate, body weight, waist circumference (WC) and the 6-min walk test will be taken. Furthermore, the blood lipid profile, glucose and HbA1c will be evaluated. Clinical interview will be conducted, and validated questionnaires completed. The primary quantitative results will be compared using an analysis of covariance adjusted for age and sex. A multivariate analysis will be performed to examine the association of the intervention with lifestyle habits, the control of cardiovascular risk factors (CDRFs) and the results after the hospital discharge (major adverse events, treatment compliance and lifestyle). Conclusions: The study will provide evidence about the effectiveness of an mHealth intervention at improving the lifestyle of the participants and could be offered to patients with coronary disease to complement existing services. Trial registration: NCT05247606. [https://ClinicalTrials.gov]. 21/02/2022.

Measuring Absolute Coronary Flow and Microvascular Resistance by Thermodilution: JACC Review Topic of the Week.

Diagnosing coronary microvascular dysfunction remains challenging, primarily due to the lack of direct measurements of absolute coronary blood flow (Q) and microvascular resistance (Rµ). However, there has been recent progress with the development and validation of continuous intracoronary thermodilution, which offers a simplified and validated approach for clinical use. This technique enables direct quantification of Q and Rµ, leading to precise and accurate evaluation of the coronary microcirculation. To ensure consistent and reliable results, it is crucial to follow a standardized protocol when performing continuous intracoronary thermodilution measurements. This document aims to summarize the principles of thermodilution-derived absolute coronary flow measurements and propose a standardized method for conducting these assessments. The proposed standardization serves as a guide to ensure the best practice of the method, enhancing the clinical assessment of the coronary microcirculation.

Coronary Flow Reserve and Myocardial Resistance Reserve Changes After Transcatheter Aortic Valve Implantation in Aortic Stenosis.

Aortic valve stenosis (AS) induces an alteration in hemodynamic conditions that are responsible for coronary microvasculature impairment. Relief of AS by transcatheter aortic valve implantation (TAVI) is expected to improve the coronary artery hemodynamic. We aimed to assess the midterm effects of TAVI in coronary flow reserve (CFR) and myocardial resistance reserve (MRR) by a continuous intracoronary thermodilution technique. At-rest and hyperemic coronary flow was measured by a continuous thermodilution technique in 23 patients with AS and compared with that in 17 matched controls, and repeated 6 ± 3 months after TAVI in 11 of the patients with AS. In patients with AS, absolute coronary flow at rest was significantly greater, and absolute resistance at rest was significantly less, than in controls (p <0.01 for both), causing less CFR and MRR (1.73 ± 0.4 vs 2.85 ± 1.1, p <0.01 and 1.95 ± 0.4 vs 3.22 ± 1.4, p <0.01, respectively). TAVI implantation yielded a significant 35% increase in CFR (p >0.01) and a 39% increase in MRR (p <0.01) driven by absolute coronary flow at rest reduction (p = 0.03). In patients with AS, CFR and MRR determined by continuous thermodilution are significantly impaired. At 6-month follow-up, TAVI improves these indexes and partially relieves the pathophysiologic alterations, leading to a partial restoration of CFR and MRR.

Outcomes Prediction in Complex High-Risk Indicated Percutaneous Coronary Interventions in the Older Patients.

Complex high-risk indicated percutaneous coronary intervention (CHIP-PCI) is a poorly defined concept, which has not been validated in an older population before. This study aimed to evaluate the predictive value of the CHIP-PCI score in a large cohort of elderly patients and to identify potential further risk factors. This is a pooled analysis of 3 registries that included patients aged ≥75 years who underwent percutaneous coronary intervention from 2012 to 2019: the multicenter prospective EPIC05-Sierra 75 study, the multicenter retrospective PACO-PCI (EPIC-15) registry, and the single-center, prospective Elderly-HCD registry. A total of 2,725 patients with a mean age of 81 ± 4 years were included in the study; 269 patients (10%) met the primary end point of 1-year major adverse cardiac and cerebrovascular events (MACCEs), and 51 patients (2%) had in-hospital MACCEs. Of the 12 investigated original CHIP-PCI score variables, 5 were independent predictors: previous myocardial infarction, left ventricular ejection fraction <30%, chronic kidney disease, left main coronary artery percutaneous coronary intervention, and nonradial access. Furthermore, diabetes mellitus, anemia, and severe calcification showed to be significant predictors of MACCEs. The additional variables improved the discriminatory value of the CHIP-PCI score for 1-year MACCEs (modified CHIP-PCI score: area under the curve [AUC] 0.647 vs original CHIP-PCI score: AUC 0.598, p = 0.02) and in-hospital MACCEs (AUC 0.729 vs 0.657, p = 0.003, respectively). In conclusion, the CHIP-PCI score retains its prognostic value in older patients for in-hospital MACCEs; however, it is of limited value at 1-year follow-up. The modified CHIP-PCI score, including the 5 patient-related and 3 procedure-related factors, significantly improved its discriminatory potential.

Treatment of Slow-Flow After Primary Percutaneous Coronary Intervention With Flow-Mediated Hyperemia: The Randomized RAIN-FLOW Study.

Background ST-segment-elevation myocardial infarction complicated with no reflow after primary percutaneous coronary intervention is associated with adverse outcomes. Although several hyperemic drugs have been shown to improve the Thrombolysis in Myocardial Infarction flow, optimal treatment of no reflow remains unsettled. Saline infusion at 20 mL/min via a dedicated microcatheter causes (flow-mediated) hyperemia. The objective is to compare the efficacy of pharmacologic versus flow-mediated hyperemia in patients with ST-segment-elevation myocardial infarction complicated with no reflow. Methods and Results In the RAIN-FLOW (Treatment of Slow-Flow After Primary Percutaneous Coronary Intervention With Flow-Mediated Hyperemia) study, 67 patients with ST-segment-elevation myocardial infarction and no reflow were randomized to receive either pharmacologic-mediated hyperemia with intracoronary adenosine or nitroprusside (n=30) versus flow-mediated hyperemia (n=37). The angiographic corrected Thrombolysis in Myocardial Infarction frame count and the minimal microcirculatory resistance, as assessed with intracoronary pressure-thermistor wire, dedicated microcatheter, and thermodilution techniques, were compared after study interventions. Both Thrombolysis in Myocardial Infarction frame count(40.2±23.1 versus 39.2±20.7; P=0.858) and minimal microcirculatory resistance (753.6±661.5 versus 993.3±740.8 Wood units; P=0.174) were similar between groups. Thrombolysis in Myocardial Infarction 3 flow was observed in 26.7% versus 27.0% (P=0.899). Flow-mediated hyperemia showed 2 different thermodilution patterns during saline infusion indicative of the severity of the no reflow phenomenon. In-hospital death and nonfatal heart failure were observed in 10.4% and 26.9%, respectively. Conclusions Both treatments showed similar (and limited) efficacy restoring coronary flow. Flow-mediated hyperemia with thermodilution pattern assessment allowed the simultaneous characterization of the no reflow degree and response to hyperemia. No reflow was associated with a high rate of adverse outcomes. Further research is warranted to prevent and to treat no reflow in patients with ST-segment-elevation myocardial infarction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04685941.

Spontaneous coronary artery dissection and ST-segment elevation myocardial infarction: Does clinical presentation matter?

BACKGROUND: Some patients with spontaneous coronary artery dissection (SCAD) present as ST-segment-elevation myocardial infarction (STEMI). This study evaluates the characteristics, management and outcomes of SCAD patients presenting as STEMI compared to non-ST-segment elevation myocardial infarction (NSTEMI). METHODS: We analysed data from consecutive patients included in the prospective Spanish Registry on SCAD. All coronary angiograms were centrally reviewed. All adverse events were adjudicated by an independent Clinical Events Committee. RESULTS: Between June 2015 to December 2020, 389 patients were included. Forty-two percent presented with STEMI and 56% with NSTEMI. STEMI patients showed a worse distal flow (TIMI flow 0-1 38% vs 19%, p < 0.001) and more severe (% diameter stenosis 85 ± 18 vs 75 ± 21, p < 0.001) and longer (42 ± 23 mm vs 35 ± 24 mm, p = 0.006) lesions. Patients with STEMI were more frequently treated with percutaneous coronary intervention (PCI) (31% vs 16%, p < 0.001) and developed more frequently left ventricular systolic dysfunction (21% vs 8%, p < 0.001). No differences were found in combined major adverse events during admission (7% vs 5%, p = 0.463), but in-hospital reinfarctions (5% vs 1.4%, p = 0.039) and cardiogenic shock (2.6% vs 0%, p = 0.019) were more frequently seen in the STEMI group. At late follow-up (median 29 months) no differences were found in the incidence of major adverse cardiac and cerebrovascular events (13% vs 13%, p-value = 0.882) between groups. CONCLUSIONS: Patients with SCAD and STEMI had a worse angiographic profile and were more frequently referred to PCI compared to NSTEMI patients. Despite these disparities, both short and long-term prognosis were similar in STEMI and NSTEMI SCAD patients.

Endothelial dysfunction in patients with angina and non-obstructed coronary arteries is associated with an increased risk of mayor cardiovascular events. Results of the Spanish ENDOCOR registry.

BACKGROUND: Coronary endothelial dysfunction and vasospasm are potential causes of ischemia in patients without obstructive coronary stenoses (INOCA). OBJECTIVE: To evaluate the prevalence of endothelial dysfunction and the clinical profile of patients with INOCA in Spain, as well as to identify the predictors and the prognostic impact of endothelial dysfunction in this scenario. METHODS: A total of 438 consecutive patients with INOCA in whom the acetylcholine test was performed were prospectively enrolled. Patients were followed up at 1 and 2 years. RESULTS: Mean age was 62 ± 11 years with 60% female. Clinical presentation comprised 52.6% angina at rest, 61.2% exertional angina, and 31.7% dyspnea. There were no major complications of the acetylcholine test. Endothelial dysfunction was observed in 198 (45%) of patients, with severe vasoconstriction (defined as over 70% constriction), being observed in 101 (23%). Multivariable regression analysis showed that endothelial dysfunction was predicted by the presence of exertional angina (OR 2.2; CI95%1.01-2.55; p = 0.02), prior coronary disease (OR 2.46; CI95% 1.57-3.89; p < 0.01), and coronary intramyocardial bridging (2.35; CI95% 1.02-5.60; p = 0.04). Patients with endothelial dysfunction presented with worsening angina compared to those without endothelial dysfunction (25.6% vs. 12.8%) and also presented with increased levels of minimal effort angina (40% vs. 26,7%, p = 0.03) more frequently during the follow up than those without endothelial dysfunction. Endothelial dysfunction was also an independent predictor of the occurrence of myocardial infarction or unstable angina at one year (OR 2.85, CI 95% 1.01-9.25; p = 0.03). CONCLUSIONS: Endothelial dysfunction is present in almost half of patients with INOCA and is associated with worsening symptoms, as well as with a higher rate of adverse events.

Early recruitable coronary collaterals preserve miocardial viability in late presentation infarctions.

BACKGROUND: Previous studies showed conflicting results regarding the contribution of coronary collateral circulation (CCC) to myocardial perfusion and function in the setting of myocardial infarction (MI). In the primary angioplasty era, the role of CCC in these studies may have been influenced by the effect of early reperfusion. The true impact of CCC could be clarified by studying its effect on nonreperfused patients. The aim of our study was to evaluate the effect of CCC on myocardial viability of late presentation MI. METHODS AND RESULTS: Between 2008 and 2019, we included 167 patients with a late presentation MI who had a complete angiographic occlusion in a major coronary artery in which myocardial viability of the culprit territory was assessed. Patients were divided according to the presence of angiographic early recruited CCC (ERCC) (Rentrop 2-3) or poor CCC (PCC) (Rentrop 0-1). A lower left ventricular ejection function (LVEF) at discharge (54.2 ± 9 vs. 47.9 ± 12; <0.01) and a more severe left ventricular wall motion abnormalities in the culprit territory were observed in PCC patients. The presence of ERCC was the main independent predictor of myocardial viability in late presentation MI (hazard ratio, 4.24; 95% confidence interval, 1.68-10.6; P < 0.001). At follow-up, wall motion score increased significantly (2.05 ± 0.16; P = 0.02) in patients with ERCC but not in PCC patients (0.07 ± 0.16; P = 0.4), and LVEF improvement was significantly higher in ERCC than in PCC patients (9.7 ± 2.6 vs. 3.8 ± 4.2; P = 0.02). CONCLUSION: The presence of ERCC was the main independent predictor of myocardial viability in late presentation MI.

Design and Validation of a Scale of Knowledge of Cardiovascular Risk Factors and Lifestyle after Coronary Event.

BACKGROUND: It is important for health professionals to have tools available to assess patients' knowledge of lifestyle and cardiovascular risk factors after they have suffered a coronary event and determine whether educational interventions are effective. This study aims to design and validate a scale to evaluate this knowledge. METHODS: Four-phase instrument design: (A) Conceptual review. (B) Review by experts. (C) Pilot test-retest. (D) Psychometric validation of the final version of the questionnaire with 24 items. A panel of experts performed the content validity. The reliability of the scale was measured using Cronbach's alpha score and criterion validity was evaluated by comparing the total scores for knowledge obtained by the participants among the three education level groups. The construct and dimensional structure validity were assessed using exploratory factor analysis. RESULTS: A total of 143 people participated, 30 in the pilot study and 113 (68% male, 60.2 ± 9 years) in the psychometric validation of version 3 of the scale. A Cronbach's alpha score of 0.887 was reached for this version. The factor analysis showed that the items were distributed into five factors that explained 57% of the variance. Significant differences were observed in the level of knowledge among the patients of the three levels of education (low, moderate and high) (99.20 ± 11.93, 105.92 ± 7.85, 109.78 ± 8.76 points, p = 0.003), as there was a negative correlation between age and knowledge level (r = -0.213, p = 0.024). CONCLUSIONS: The scale presents psychometric properties that are evidence of its reliability and validity. The relationship demonstrated between the level of knowledge and age, sex and level of education shows the importance of emphasizing educational interventions for elderly people and those with a lower level of education.

Radiation protection for the interventional cardiologist: Practical approach and innovations.

Use of ionizing radiation during cardiac catheterization interventions adversely impacts both the patients and medical staff. In recent years, radiation dose in cardiac catheterization interventions has become a topic of increasing interest in interventional cardiology and there is a strong interest in reducing radiation exposure during the procedures. This review presents the current status of radiation protection in the cardiac catheterization laboratory and summarizes a practical approach for radiation dose management for minimizing radiation exposure. This review also presents recent innovations that have clinical potential for reducing radiation during cardiac interventions.

Instantaneous wave-free ratio for guiding treatment of nonculprit lesions in patients with acute coronary syndrome: A retrospective study.

BACKGROUND: The aim of this study was to analyze the feasibility of a physiological coronary evaluation with the instantaneous wave-free ratio (iFR) of nonculprit lesions in patients with acute coronary syndrome (ACS) successfully revascularized. METHODS: A multicenter registry including patients of four high-volume PCI centers with ACS and underwent successful revascularization of the culprit vessel and had other nonculprit lesions that were physiologically evaluated with the iFR between January 2017 and December 2019. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction, probable or definitive stent thrombosis and new revascularization (MACEs). RESULTS: A total of 356 patients with 472 nonculprit lesions were included. The mean age was 66 ± 11 years. The clinical presentation was ACS without persistent ST-segment elevation (NSTE-ACS) in 235 patients (66%) and ST-segment elevation myocardial infarction (STEMI) in 121 patients (34%). After a median follow-up period of 21 (14-30) months, the primary endpoint occurred in 32 patients (9%). There were no differences in outcomes regarding clinical presentation (NSTEMI vs. NSTE-ACS, 9.1 vs. 8.9%, padj  = 0.570) or iFR induced treatment strategy (patients with all lesions revascularized vs. patients with at least one lesion with an iFR > 0.89 deferred for revascularization, 10.5 vs. 8.4%, padj  = 0.476). CONCLUSIONS: The use of the iFR to guide percutaneous coronary intervention decision making in nonculprit lesions seems to be feasible, with an acceptable percentage of MACEs at the mid-term follow-up. Patients with deferred revascularization of lesions without physiological significance and patients undergoing complete revascularization had a similar risk of MACEs.

Lifestyle and Treatment Adherence Intervention after a Coronary Event Based on an Interactive Web Application (EVITE): Randomized Controlled Clinical Trial Protocol.

Coronary heart disease is one of the main causes of morbimortality around the world. Patients that survive a coronary event suffer a high risk of readmission, relapse and mortality, attributed to the sub-optimal control of cardiovascular risk factors (CVRF), which highlights the need to improve secondary prevention strategies aimed at improving their lifestyle and adherence to treatment. Through a randomized controlled clinical trial, this study aims to evaluate the effect of an intervention involving an online health application supported by a mobile telephone or tablet (mHealth) on lifestyle (diet, physical activity, and tobacco consumption) and treatment adherence among people with coronary heart disease after percutaneous coronary intervention. The sample will comprise 240 subjects (120 in each arm: intervention and usual care). They are assessed immediately and nine months after their hospital discharge about sociodemographic, clinical, CVRF, lifestyle, and treatment adherence characteristics. The educative intervention, involving a follow-up and self-monitoring, will be performed using an online mHealth tool consisting of an application for mobile phones and tablets. The quantitative primary outcomes from the two groups will be compared using an analysis of covariance (ANCOVA) adjusted for age and gender. A multivariate analysis will be performed to examine the association of the intervention with lifestyle habits, the control of CVRFs, and outcomes after discharge in terms of the use of health services, emergency visits, cardiovascular events and readmissions.

The radioprotective effect of the Cathpax® AIR cabin during interventional cardiology procedures.

BACKGROUND: The use of ionizing radiation during cardiac catheterization interventions adversely impacts the medical staff. Traditional radiation protection equipment is only partially effective. The Cathpax® radiation protection cabin (RPC) has proven to significantly reduce radiation exposure in electrophysiological and neuroradiology interventions. Our objective was to analyze whether the Cathpax® RPC reduces radiation dose in coronary and cardiac structural interventions in unselected real-world procedures. METHODS AND RESULTS: In this nonrandomized all-comers prospective study, 119 consecutive cardiac interventional procedures were alternatively divided into two groups: the RPC group (n = 59) and the non-RPC group (n = 60). No significant changes in the characteristics of patients and procedures, average contrast volume, air kerma (AK), dose area-product (DAP) and fluoroscopy time between both groups were apparent. In the RPC group, the first-operator relative radiation exposure was reduced by 78% at the chest and by 70% at the wrist. This effect was consistent during different types of procedures including complex percutaneous interventions and structural procedures. CONCLUSIONS: Our study demonstrates, for the first time, that the Cathpax® cabin significantly and efficiently reduces relative operator radiation exposure during different types of interventional procedures, confirming its feasibility in a real-world setting.

Impact of diabetes in patients waiting for invasive cardiac procedures during COVID-19 pandemic.

BACKGROUND: During COVID-19 pandemic, elective invasive cardiac procedures (ICP) have been frequently cancelled or postponed. Consequences may be more evident in patients with diabetes. OBJECTIVES: The objective was to identify the peculiarities of patients with DM among those in whom ICP were cancelled or postponed due to the COVID-19 pandemic, as well as to identify subgroups in which the influence of DM has higher impact on the clinical outcome. METHODS: We included 2,158 patients in whom an elective ICP was cancelled or postponed during COVID-19 pandemic in 37 hospitals in Spain. Among them, 700 (32.4%) were diabetics. Patients with and without diabetes were compared. RESULTS: Patients with diabetes were older and had a higher prevalence of other cardiovascular risk factors, previous cardiovascular history and co-morbidities. Diabetics had a higher mortality (3.0% vs. 1.0%; p = 0.001) and cardiovascular mortality (1.9% vs. 0.4%; p = 0.001). Differences were especially important in patients with valvular heart disease (mortality 6.9% vs 1.7% [p < 0.001] and cardiovascular mortality 4.9% vs 0.9% [p = 0.002] in patients with and without diabetes, respectively). In the multivariable analysis, diabetes remained as an independent risk factor both for overall and cardiovascular mortality. No significant interaction was found with other clinical variables. CONCLUSION: Among patients in whom an elective invasive cardiac procedure is cancelled or postponed during COVID-19 pandemic, mortality and cardiovascular mortality is higher in patients with diabetes, irrespectively on other clinical conditions. These procedures should not be cancelled in patients with diabetes.

Coronary microvascular dysfunction assessed by continuous intracoronary thermodilution: A comparative study with index of microvascular resistance.

BACKGROUND: This study aimed to assess the correlation between the standard of care, the index of microvascular resistance (IMR) versus the novel microvascular resistance (Rmicro) and to determine the pathologic cut-off value in a selected population with suspected coronary microvascular dysfunction (CMD). METHODS: One-hundred and twenty patients with high clinical suspicion of CMD due to ischemic symptoms in the absence of significant epicardial coronary lesions were prospectively included. Following a standardized systematic protocol, coronary flow reserve, IMR, fractional flow reserve, Q and Rmicro were measured in the left anterior descending coronary artery using a temperature/pressure sensor-tipped guidewire and a dedicated infusion catheter. RESULTS: There was a high prevalence of CMD with 50 (42%) patients showing an IMR ≥ 25. Median IMR was 23 [IQR: 14-34] and median Rmicro was 464 Woods Units (WU) [IQR: 354-636WU]. ROC analyses identified 500 WU as the optimal Rmicro cut-off to identify patients with an IMR ≥ 25, with an area under the ROC curve (C statistic) of 0.83 (95% CI: 0.74 to 0.89, p < 0.0001). CONCLUSIONS: Rmicro derived from continuous intracoronary thermodilution is an accurate index to measure microvascular resistances enabling the invasive diagnostic of CMD.