Prognostic Value of Microvascular Resistance at Rest in Patients With Takotsubo Syndrome

Culprit-Lesion Drug-Coated-Balloon Percutaneous Coronary Intervention in Patients Presenting with ST-Elevation Myocardial Infarction (STEMI)

Background/Objectives: Drug-eluting stents (DESs) remain the standard of treatment for patients with ST-elevation myocardial infarction (STEMI). However, complications such as stent thrombosis and in-stent restenosis still pose significant risks. Drug-coated balloons (DCBs) have emerged as a promising alternative, but data for this clinical scenario are still scarce. The objective was to evaluate the safety and efficacy of DCB culprit-lesion primary percutaneous coronary intervention (pPCI) in patients presenting with STEMI and to evaluate its impact on the microcirculatory territory. Methods: An observational retrospective study was conducted across six European centers. Results: In total, 118 patients were included. Of these, 82.2% were male, with a median age of 67 years (IQR 36-92); 28% patients presented with stent thrombosis and most of them (94%) underwent paclitaxel-DCB-pPCI. The median follow-up was 23.2 months (IQR 6.7-77.3). Target lesion failure (TLF) rates were low (3.4%), with no differences between patients presenting with native coronary vessel and stent thrombosis (4.7% vs. 0%; p = 0.205). Overall mortality rates at follow-up were 7%, with only 1.8% attributed to cardiac causes. A target lesion revascularization (TLR) rate of 1.8% was observed, with no target vessel myocardial infarction reported. A subgroup of patients (42; 35.6%) underwent an adenosine-free angiographic microvascular resistance (AMR) analysis. The median AMR was 4.7 (3.9-5.5) and was greater in the stent thrombosis group than in the native coronary group (5.1 vs. 4.6; p = 0.038) with no clinical differences between patients based on the AMR. Conclusions: DCB-pPCI has emerged as an alternative potential treatment for patients presenting with STEMI, with few long-term adverse cardiac events. Despite the encouraging outcomes, these findings underscore the need for a large randomized clinical trial powered by a relevant clinical outcome in order to elucidate the role of DCB-PCI in patients presenting with STEMI.

Non-atherosclerotic coronary causes of myocardial infarction in women

Ischemic heart disease is the most common cardiovascular cause of death in women worldwide. Obstructive coronary atherosclerosis is the primary cause of myocardial infarction (MI), however, non-atherosclerotic mechanisms of MI, such as spontaneous coronary artery dissection, vasospasm, microvascular dysfunction, embolization, inflammation, coronary anomalies, infectious and infiltrative causes are increasingly being recognized. Emerging data suggest that women are two to five times more likely to have an MI in the absence of coronary atherosclerosis compared to men, but they continue to remain underdiagnosed and undertreated, partly due to underdiagnosis and limited understanding of these mechanisms. Recent advancements in invasive and noninvasive imaging techniques and physiological testing allow for distinguishing these mechanisms from each other, providing a definitive diagnosis and tailored treatment. This review summarizes the existing literature on the non-atherosclerotic coronary causes of MI with a focus on evidence pertaining to women, offering a basis for future studies.

Association between the Tpeak-Tend interval on admission and coronary microvascular dysfunction in Takotsubo syndrome

AIMS

The Tpeak-Tend interval on electrocardiogram may be a predictor of worse outcomes in Takotsubo syndrome (TTS), but the mechanisms have not been fully determined. This study aimed to investigate the relationships between the corrected Tpeak-Tend (cTp-e) interval and coronary microvascular-dysfunction (CMD) assessed by the angiography-derived index of microvascular resistance (Angio-IMR) and the in-hospital prognosis in patients with TTS.

METHODS AND RESULTS

We retrospectively evaluated 111 consecutive patients admitted for TTS who underwent coronary angiography at Kindai University Hospital from October 2009 to July 2023. The Tpeak-Tend interval was defined as the time interval between the peak and the end of the T wave in electrocardiogram lead V5 on admission. Angio-IMR was assessed from aortic pressure, quantitative flow ratio (QFR), vessel length and hyperemic velocity using the formula described in validation studies. QFR, vessel length and hyperemic velocity was derived from coronary angiography and QAngio XA 3D software package. The degree of CMD was assessed by the maximum Angio-IMR value in each of the three coronary arteries. The primary endpoint was the relationship between the grade of a prolonged cTp-e interval on admission and Angio-IMR. The secondary endpoint was the relationship between the grade of a prolonged cTp-e interval on admission and in-hospital adverse cardiovascular events (composite of acute heart failure, cardiogenic shock, life-threatening arrhythmia, thrombotic events, stroke and all-cause death). The median age was 77.5 [71.0-83.0] years, and most patients were women (82.0%). The median cTp-e interval was 114.5 [91.2-147.0] ms. The patients were categorized according to the tertiles of the cTp-e interval (T1: 52.4-96.9 ms; T2: 100.1-129.1 ms; T3: 131.7-309.8 ms). There was a stepwise increment in the values of maximum Angio-IMR in each of the three coronary arteries in tertiles of the cTp-e interval (T1 vs. T2 vs. T3: 16.1 [14.7-19.3] vs. 21.8 [16.0-31.1] vs. 29.0 [27.2-31.9], P < 0.001). In-hospital adverse cardiovascular events occurred in 53 of 111 patients (47.7%). There was a stepwise increment in the incidence of in-hospital adverse cardiovascular events in tertiles of the cTp-e interval (T1 vs. T2 vs. T3: 27.1% vs. 54.1% vs. 62.2%, P = 0.007). The multivariable analysis showed that prolonged cTp-e interval (OR: 1.30; 95% CI: 1.12-1.56; P < 0.001) was independent predictors of in-hospital adverse cardiovascular events.

CONCLUSIONS

The Tpeak-Tend interval on admission reflected CMD and predicts in-hospital adverse cardiovascular events in patients with TTS.

Myocardial microvascular function assessed by cardiovascular magnetic resonance first-pass perfusion in patients with Takotsubo syndrome

OBJECTIVE

The purpose of this study was to explore microvascular function impairment using first-pass cardiovascular magnetic resonance (CMR) in patients with Takotsubo syndrome (TS). Moreover, we explored myocardial microcirculation in patients with TS and related this to demographic data, cardiovascular risk factors, clinical parameters, cardiac biomarkers, and cardiac function.

METHODS

This retrospective study performed CMR first-pass perfusion scans in 42 consecutive patients with TS (37 females, 70.6 ± 9.4 years). Moreover, we included 44 sex- and age-matched healthy controls (33 females, 66.4 ± 10.5 years). CMR-derived myocardial microcirculation function was analyzed and compared between TS patients and controls.

RESULTS

Compared to age-, sex-, and cardiovascular risk factors-matched control group, TS patients demonstrated a lower perfusion index (PI) (0.140 ± 0.060 vs. 0.182 ± 0.056, p = 0.001). In multivariable analysis with adjustment for demographic data and cardiovascular risk factors, an impairment in PI was independently associated with left ventricle ejection fraction (β coefficient = 3.793, p = 0.001) and T2 mapping (β coefficient = -4.316, p = 0.001).

CONCLUSION

TS patients exhibited myocardial microvascular dysfunction, which was non-invasively assessed using first-pass CMR. This impaired myocardial microvascular function was found to be independently associated with left ventricular ejection fraction and myocardial edema.

KEY POINTS

Question Can cardiovascular magnetic resonance (CMR) cardiac MR first-pass perfusion help to better understand Takotsubo pathophysiology by exploring microvascular impairment? Findings CMR first-pass perfusion revealed significant microvascular dysfunction during the acute phase of Takotsubo syndrome, independently associated with left ventricular ejection fraction and myocardial edema. Clinical relevance Identifying an abnormal microvascular network using non-invasive biomarkers could enhance risk stratification and guide tailored management during the acute phase of Takotsubo syndrome.

Diagnostic performance of multi-branch coronary angiography-based index of microcirculatory resistance: a novel approach

Background

Wire-based index of microcirculatory resistance (IMR) utilizing pressure wires and thermodilution techniques for the assessment of coronary microcirculatory function, presents challenges for clinical routine use due to its complexity, time-consuming, and costly. This study introduces a novel multi-branch and wire-free method for IMR calculation based on coronary angiography. The diagnostic performance of CAG-IMR is validated within a retrospective single-center investigation.

Methods

In a retrospective single-center study, 139 patients with 201 vessels were evaluated using CAG-IMR for coronary microvascular dysfunction (CMD) detection, utilizing wire-based IMR as the reference standard. CMD was determined based on wire-based IMR ≥25U. CAG-IMR was independently calculated from diagnostic coronary angiography in a blinded fashion, employing the same diagnostic threshold of 25U for CMD identification.

Results

CAG-IMR demonstrated significant correlation (r = 0.84, p < 0.001) and good diagnostic performance AUC = 0.97 (95% CI: 0.95-0.99) compared to wire-based IMR. It exhibited the overall diagnostic accuracy at 95.0% (95% CI: 92.0%-98.0%), alongside high sensitivity (92.7%) and specificity (95.6%). The positive predictive value (PPV) stood at 84.4%, and the negative predictive value (NPV) reached 98.1%.

Conclusions

This study introduces CAG-IMR, a novel, multi-branch and wire-free method for IMR calculation. The indicator demonstrates good diagnostic accuracy and correlation with wire-based IMR in a cohort of 139 patients and 201 vessels, with the potential to enhance clinical CMD assessment.

Coronary Microvascular Function in Asymptomatic Middle-Aged Individuals With Cardiometabolic Risk Factors

BACKGROUND

In patients with ischemic heart disease, coronary microvascular dysfunction is associated with cardiovascular risk factors and poor prognosis; however, data from healthy individuals are scarce.

OBJECTIVES

The purpose of this study was to assess the impact of cardiovascular risk factors and subclinical atherosclerosis on coronary microvascular function in middle-aged asymptomatic individuals.

METHODS

Myocardial perfusion was measured at rest and under stress using cardiac magnetic resonance in 453 individuals and used to generate myocardial blood flow (MBF) maps and calculate myocardial perfusion reserve (MPR). Subclinical atherosclerosis was assessed using 3-dimensional vascular ultrasound of the carotid and femoral arteries and coronary artery calcium scoring at baseline and at 3-year follow-up.

RESULTS

Median participant age was 52.6 years (range: 48.9-55.8 years), and 84.5% were male. After adjusting for age and sex, rest MBF was directly associated with the number of the metabolic syndrome components present (elevated waist circumference, systolic and diastolic blood pressure, fasting glucose, and triglycerides and low high-density lipoprotein cholesterol), insulin resistance (homeostatic model assessment for insulin resistance), and presence of diabetes. MPR was reduced in the presence of several metabolic syndrome components, elevated homeostatic model assessment for insulin resistance, and diabetes. Stress MBF was inversely associated with coronary artery calcium presence and with global plaque burden. Higher stress MBF and MPR were associated with less atherosclerosis progression (increase in plaque volume) at 3 years.

CONCLUSIONS

In asymptomatic middle-aged individuals free of known cardiovascular disease, the presence of cardiometabolic risk factors and systemic (poly-vascular) subclinical atherosclerosis are associated with impaired coronary microvascular function. Better coronary microvascular function reduces atherosclerosis progression at follow-up. (Progression of Early Subclinical Atherosclerosis [PESA]; NCT01410318).

Coronary microvascular dysfunction in Takotsubo syndrome: an analysis using angiography-derived index of microcirculatory resistance

BACKGROUND

Coronary microvascular dysfunction (CMD) has been proposed as a crucial factor in the pathophysiology of Takotsubo syndrome (TTS). The angiography-derived index of microcirculatory resistance (caIMR) offers an alternative to conventional hyperemic wire-based IMR to assess CMD. We aimed to evaluate CMD's prevalence, transience, and impact on in-hospital outcomes in TTS.

METHODS

All three coronary arteries of 96 patients with TTS were assessed for their coronary angiography derived Index of microcirculatory Resistance (caIMR) and compared to non-obstructed vessels of matched patients with ST-elevation myocardial infarction. Further, the association between caIMR and the TTS-specific combined in-hospital endpoint of death, cardiac arrest, ventricular arrhythmogenic events and cardiogenic shock was investigated.

RESULTS

Elevated IMR was present in all TTS patients, with significantly elevated caIMR values in all coronary arteries compared to controls. CaIMR did not differ between apical and midventricular TTS types. CaIMR normalized in TTS patients with follow-up angiographies performed at a median of 28 months (median caIMR at event vs follow-up: LAD 34.8 [29.9-41.1] vs 20.3 [16.0-25.3], p < 0.001; LCX: 38.7 [32.9-50.1] vs 23.7 [19.4-30.5], p < 0.001; RCA: 31.7 [25.0-39.1] vs 19.6 [17.1-24.0], p < 0.001). The extent of caIMR elevation significantly correlated with the combined in-hospital endpoint (p = 0.036).

CONCLUSION

TTS patients had evidence of elevated caIMR in at least one coronary artery with a trend towards higher LAD caIMR in apical type TTS and normalization after recovery. Furthermore, extent of caIMR elevation was associated with increased risk of in-hospital MACE of TTS patients.

Coronary microvascular dysfunction beyond the spectrum of chronic coronary syndromes

The prevalence of coronary microvascular dysfunction (CMD) beyond the spectrum of chronic coronary syndromes (CCS) is non-negligible, pertaining to pathophysiological and therapeutical implications. Thanks to the availability of accurate and safe non-invasive technique, CMD can be identified as a key player in heart failure, cardiomyopathies, Takotsubo syndrome, aortic stenosis. While CMD is widely recognized as a cause of myocardial ischemia leading to a worse prognosis even in the absence of obstructive coronary artery disease, the characterization of CMD patterns beyond CCS might provide valuable insights on the underlying disease progression, being potentially a "red flag" of adverse cardiac remodeling and a major determinant of response to therapy and outcomes. In this review, we aimed to provide an overview of the latest evidence on the prevalence, mechanistic and prognostic implications of CMD beyond the spectrum of CCS (i.e. heart failure, cardiomyopathies, Takotsubo syndrome, aortic stenosis).

Stress-induced cardiomyopathy by dobutamine stress echocardiography during recovery stage - A rare presentation

Stress-induced cardiomyopathy is a condition of acute myocardial suppression following an abrupt release of endogenous catecholamines after emotional or physical stress. The exact mechanism is unknown but there are reports of a similar clinical presentation after injection of exogenous catecholamines such as beta agonists. We report a rare type of stress-induced cardiomyopathy following injection of dobutamine during a diagnostic stress echocardiography.

Learning objective

Stress-induced cardiomyopathy by dobutamine stress echocardiography is a rare entity and it should be included as a differential cause of regional wall motion abnormality during stress echocardiography. Physicians must be aware of this since treatment and follow up of these patients may differ from those for other patients and it may cause heart failure.

Impact of the use of plaque modification techniques on coronary microcirculation using an angiography-derived index of microcirculatory resistance

Many lesions in patients undergoing percutaneous coronary intervention (PCI) exhibit significant calcification. Several techniques have been developed to improve outcomes in this setting. However, their impact on coronary microcirculation remains unknown. The aim of this study is to evaluate the influence of plaque modification techniques on coronary microcirculation across patients with severely calcified coronary artery disease. In this multicenter retrospective study, consecutive patients undergoing PCI with either Rotablation (RA) or Shockwave-intravascular-lithotripsy (IVL) were included. Primary endpoint was the impairment of coronary microvascular resistances assessed by Δ angiography-derived index of microvascular resistance (ΔIMRangio) which was defined as the difference in IMRangio value post- and pre-PCI. Secondary endpoints included the development of peri procedural PCI complications (flow-limiting coronary dissection, slow-flow/no reflow during PCI, coronary perforation, branch occlusion, failed PCI, stroke and shock developed during PCI) and 12-month follow-up adverse events. 162 patients were included in the analysis. Almost 80% of patients were male and the left descending anterior artery was the most common treated vessel. Both RA and IVL led to an increase in ΔIMRangio (22.3 and 10.3; p = 0.038, respectively). A significantly higher rate of PCI complications was observed in patients with ΔIMRangio above the median of the cohort (21.0% vs. 6.2%; p = 0.006). PCI with RA was independently associated with higher ΔIMRangio values (OR 2.01, 95% CI: 1.01-4.03; p = 0.048). Plaque modification with IVL and RA during PCI increases microvascular resistance. Evaluating the microcirculatory status in this setting might help to predict clinical and procedural outcomes and to optimize clinical results.

Impact of age on the outcomes of Takotsubo syndrome

BACKGROUND

The impact on age on the short-term and long-term prognosis in patients with Takotsubo syndrome (TTS) is unclear. We aimed to evaluate whether age has prognostic implications during hospital stay and long-term follow-up of TTS patients.

METHODS

688 consecutive patients were admitted for TTS in 7 tertiary centers from January-2008 to June-2021. We divided our cohort into two groups (patients <75 years and ≥75 years). Clinical, analytical, and hemodynamic variables as well as in-hospital management were registered and compared between groups. Mortality rates during hospital stay and follow-up were assessed. Adverse cardiovascular events (ACE) were defined as the composite of cardiovascular death, heart failure event, acute myocardial infarction, stroke and symptomatic arrhythmia.

RESULTS

Median age was 74.7 years and 49.4 % were ≥75 years. 86.9 % were women and 22.3 % were secondary forms of TTS. In-hospital mortality was 3.6 % (1.5 % cardiovascular). Median clinical follow-up was 4.3 years. Mortality during the follow-up period was 23 % (5.0 % cardiovascular) while ACE were 22.5 %, mainly due to heart failure events. Kaplan-Meier curves showed both higher rates of mortality and ACE in ≥75 years group (30.2 % vs 15.8 %; p < 0.001 and 28.3 % vs 16.7 %; p < 0.001). Age was independently associated with higher rates of overall mortality and ACE in patients with TTS. Hypertension, absence of sinus rhythm, Killip class > I and a more impaired coronary microvascular resistance were also associated to ACE in TTS patients.

CONCLUSIONS

Advanced age was associated with higher rate of overall mortality and ACE during long-term follow-up in TTS patients.

Prognostic value of coronary microvascular dysfunction in patients with aortic stenosis and nonobstructed coronary arteries

BACKGROUND

Patients with aortic valve stenosis have been postulated to have coronary microvascular dysfunction (CMD) contributing to the clinical symptoms and adverse outcomes. The coronary angiography (CAG)-derived index of microcirculatory resistance (caIMR) is proposed as a novel, less invasive and pressure-wire-free index to assess CMD. This study aimed to quantify CMD assessed by caIMR and investigate its prognostic impact in patients with aortic valve stenosis.

METHODS

This study included 77 moderate or severe aortic valve stenosis patients with no obstructive coronary disease (defined as having no stenosis more than 50% in diameter) who underwent caIMR measurement. CMD was defined by caIMR at least 25. Major adverse cardiovascular events (MACE) were the clinical outcomes during the median 40 months of follow-up.

RESULTS

The incidence of CMD was 47.7%. Seventeen MACE occurred during the follow-up duration. CMD was associated with an increased risk of MACE (log-rank P < 0.001) and an independent predictor of clinical outcomes [hazard ratio 5.467, 95% confidence interval (CI) 1.393-21.458; P = 0.015]. The receiver-operating characteristic (ROC) curve analysis demonstrated that caIMR could provide a significant predictive value for MACE in aortic valve stenosis patients (AUC 0.785, 95% CI 0.609-0.961, P < 0.001). In addition, the risk of MACE was higher in CMD patients with severe aortic valve stenosis (log-rank P < 0.001) and no aortic valve replacement (log-rank P = 0.003) than in other groups.

CONCLUSION

Aortic valve stenosis patients demonstrated markedly impaired caIMR. CMD assessed by caIMR increases the risk of MACE and is an independent predictor of adverse outcomes in aortic valve stenosis patients. This finding suggests that using caIMR in the clinical assessment may help identify high-risk groups and stimulate earlier intervention.

Comprehensive invasive evaluation of coronary microcirculation in patients with Takotsubo syndrome

BACKGROUND AND AIMS

The etiology and pathophysiology of Takotsubo syndrome (TTS) remain a matter of debate. In murine models of coronary microvascular dysfunction (CMD), abnormalities in myocardial perfusion led to the development of TTS. Importantly, TTS was reversible when normal perfusion was restored. However, in clinical practice, the assessment of coronary microcirculation in patients with TTS has primarily relied on non-invasive or indirect, angiography-derived methods.

METHODS AND RESULTS

For the first time, we performed invasive microcirculatory assessment, by both validated techniques currently available in the catheterization laboratory, namely intracoronary bolus and continuous thermodilution, in patients with TTS, upon hospital admission and at short term follow-up. Our findings demonstrate that CMD was consistently present in all patients upon hospital admission, as assessed by both techniques. At a median follow-up of 3 months, after the recovery of left ventricular ejection fraction, two third of patients no longer exhibited CMD.

CONCLUSIONS

These findings support the hypothesis that an acute and transient worsening in coronary microvascular function plays a pivotal role in the pathophysiology of TTS.

Impact of Isolated Coronary Microvascular Disease Diagnosed Using Various Measurement Modalities on Prognosis: An Updated Systematic Review and Meta-Analysis

INTRODUCTION

The main aim of this study was to investigate the impact of isolated coronary microvascular disease (CMD) as diagnosed via various modalities on prognosis.

METHODS

A systematic literature review of PubMed, Embase, and Cochrane Library databases was conducted to identify relevant studies published up to March 2023. Included studies were required to measure coronary microvascular function and report outcomes in patients without obstructive coronary artery disease (CAD) or any other cardiac pathological characteristics. The primary endpoint was all-cause mortality, and the secondary endpoint was a major adverse cardiac event (MACE). Pooled effects were calculated using random effects models.

RESULTS

A total of 27 studies comprising 18,204 subjects were included in the meta-analysis. Indices of coronary microvascular function measurement included coronary angiography-derived index of microcirculatory resistance (caIMR), hyperemic microcirculatory resistance (HMR), coronary flow reserve (CFR), and so on. Patients with isolated CMD exhibited a significantly higher risk of mortality (OR: 2.97, 95% CI, 1.91-4.60, p < 0.0001; HR: 3.38, 95% CI, 1.77-6.47, p = 0.0002) and MACE (OR: 5.82, 95% CI, 3.65-9.29, p < 0.00001; HR: 4.01, 95% CI, 2.59-6.20, p < 0.00001) compared to those without CMD. Subgroup analysis by measurement modality demonstrated consistent and robust pooled effect estimates in various subgroups.

CONCLUSION

CMD is significantly associated with an elevated risk of mortality and MACE in patients without obstructive CAD or any other identifiable cardiac pathologies. The utilization of various measurement techniques may have potential advantages in the management of isolated CMD.

Prognostic Value of Post-PCI Angiography-Derived Fractional Flow Reserve: A Systematic Review and Meta-Analysis of Cohort Studies

The post-percutaneous coronary intervention (post-PCI) fractional flow reserve (FFR) can detect suboptimal PCI or residual ischemia and potentially lead to fewer adverse clinical outcomes. We sought to investigate the predictive value of the angiography-derived FFR for adverse cardiovascular events in patients after PCI. We conducted a comprehensive search of electronic databases, MEDLINE, EMBASE, and the Cochrane Library, for studies published until March 2023 that investigated the prognostic role of angiography-derived fractional flow reserve values after PCI. We investigated the best predictive ability of the post-PCI angiography-derived FFR and relative risk (RR) estimates with 95% confidence intervals (CIs) between post-PCI angiography-derived FFR values and adverse events. Thirteen cohort studies involving 6961 patients (9719 vascular lesions; mean follow-up: 2.2 years) were included in this meta-analysis. The pooled HR of the studies using specific cut-off points for post-PCI angiography-derived FFR was 4.13 (95% CI, 2.92-5.82) for total cardiovascular events, while the pooled HRs for target vessel revascularization, cardiac death, target vessel myocardial infarction, and target lesion revascularization were 6.87 (95% CI, 4.93-9.56), 6.17 (95% CI, 3.52-10.80), 3.98 (95% CI, 2.37-6.66) and 6.27 (95% CI, 3.08-12.79), respectively. In a sensitivity analysis of three studies with 1789 patients assessing the predictive role of the post-PCI angiography-derived FFR as a continuous variable, we found a 58% risk reduction for future adverse events per 0.1 increase in the post-PCI angiography-derived FFR value. In conclusion, post-PCI angiography-derived FFR is an effective tool for predicting adverse cardiovascular events and could be potentially used in decision making, both during PCI and in the long-term follow-up.

Angiography-derived index of microvascular resistance in takotsubo syndrome

Coronary microvascular dysfunction (CMD) has been proposed as a key driver in the etiopathogenesis of Takotsubo syndrome (TTS), likely related to an "adrenergic storm" upon a susceptible microvascular circulation. The aim of our manuscript was to assess CMD in patients with TTS through the computation of the angiography-derived index of microcirculatory resistance (IMR) and its correlation with clinical presentation. Coronary angiograms of 41 consecutive TTS patients were retrospectively analyzed to derive angiography-based indices of CMD. Three indices (NH-IMRangio, AngioIMR and A-IMR) were calculated based on quantitative flow ratio. CMD was defined as an IMRangio value ≥ 25 units. The correlation between CMD and clinical presentation was then assessed. Median age was 76 years, 85.7% were women and mean left ventricular ejection fraction (LVEF) at first echocardiogram was 41.2%. Angiography-derived IMR was higher in left anterior descending artery (LAD) than circumflex and right coronary artery with either NH-IMRangio (53.9 ± 19.8 vs 35.8 ± 15.4 vs 40.8 ± 18.5, p-value < 0.001), AngioIMR (47.2 ± 17.3 vs 31.8 ± 12.2 vs 37.3 ± 13.7, p-value < 0.001) or A-IMR (52.7 ± 19 vs 36.1 ± 14.1 vs 41.8 ± 16.1, p-value < 0.001). All patients presented CMD with angiography-derived IMR ≥ 25 in at least one territory with each formula. Angiography-derived IMR in LAD territory was significantly higher in patients presenting with LVEF impairment (≤ 40%) than in those with preserved ventricular global function (NH-IMRangio: 59.3 ± 18.1 vs 46.3 ± 16.0 p-value = 0.030; AngioIMR: 52.9 ± 17.8 vs 41.4 ± 14.2, p-value = 0.037; A-IMR: 59.2 ± 18.6 vs 46.3 ± 17.0, p-value = 0.035). CMD assessed with angiography-derived IMR is a common finding in TTS and it is inversely correlated with LV function. The available formulas have a substantial superimposable diagnostic performance in assessing coronary microvascular function.

Incremental prognostic value of global longitudinal strain to the coronary microvascular resistances in Takotsubo patients

BACKGROUND

Global longitudinal strain (GLS) allows an accurate assessment of left ventricular function with prognostic value. We aimed to evaluate whether the assessment of GLS in the acute phase of Takotsubo syndrome (TTS) provides incremental prognostic value to the degree of impaired microvascular resistance (MR) in TTS patients at 1-year follow-up.

METHODS

We recruited patients admitted for TTS who underwent cardiac angiography and echocardiography from January 2017 to June 2020. Left anterior descending coronary artery non-hyperaemic angiography-derived index of microcirculatory resistance (LAD NH-IMRangio) was calculated. NT-proBNP, high-sensitive cardiac troponin T (hs-cTnT), left ventricular ejection fraction (LVEF) and GLS were measured at admission. Major adverse cardiac events (MACE) were defined as the composite of cardiovascular death, repeat hospitalizations for heart failure (HF) and acute myocardial infarctions.

RESULTS

67 patients had both GLS and NH-IMRangio available and were included in the study. Median age was 75.2 years and 88% were women. Rate of MACE at 1-year was 13.4%. Kaplan-Meier curves showed higher rates of MACE at 1-year in patients with both higher LAD NH-IMRangio and GLS values compared with those with higher LAD NH-IMRangio and lower GLS values (33.3% vs. 11.1%; p = 0.049). NT-proBNP levels at admission and the recovery of LVEF were correlated with GLS values while MR and hs-cTnT were not.

CONCLUSION

GLS provides incremental prognostic value to the degree of impaired MR in TTS patients. The combination of a poorer GLS with a higher degree of impaired MR was associated with a higher rate of MACE in these patients.

In Vivo Validation of a Novel Computational Approach to Assess Microcirculatory Resistance Based on a Single Angiographic View

(1) Background: In spite of the undeniable clinical value of the index of microvascular resistance (IMR) in assessing the status of coronary microcirculation, its use globally remains very low. The aim of this study was to validate the novel single-view, pressure-wire- and adenosine-free angiographic microvascular resistance (AMR) index, having the invasive wire-based IMR as a reference standard. (2) Methods: one hundred and sixty-three patients (257 vessels) were investigated with pressure wire-based IMR. Microvascular dysfunction (CMD) was defined by IMR ≥ 25. AMR was independently computed from the diagnostic coronary angiography in a blinded fashion. (3) Results: AMR demonstrated a good correlation (r = 0.83, p < 0.001) and diagnostic performance (AUC 0.94; 95% CI: 0.91 to 0.97) compared with wire-based IMR. The best cutoff value for AMR in determining IMR ≥ 25 was 2.5 mmHg*s/cm. The overall diagnostic accuracy of AMR was 87.2% (95% CI: 83.0% to 91.3%), with a sensitivity of 93.5% (95% CI: 87.0% to 97.3%), a specificity of 82.7% (95% CI: 75.6% to 88.4%), a positive predictive value of 79.4% (95% CI: 71.2% to 86.1%) and a negative predictive value of 94.7% (95% CI: 89.3% to 97.8%). No difference in terms of CMD rate was described among different clinical presentations. (4) Conclusions: AMR derived solely from a single angiographic view is a feasible computational alternative to pressure wire-based IMR, with good diagnostic accuracy in assessing CMD.