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.

Effectiveness of radiation protection systems in the cardiac catheterization laboratory: a comparative study.

BACKGROUND: As numbers and complexity of percutaneous coronary interventions are constantly increasing, optimal radiation protection is required to ensure operator safety. Suspended radiation protection systems (SRPS) and protective scatter-radiation absorbing drapes (PAD) are novel methods to mitigate fluoroscopic scattered radiation exposure. The aim of the study was to investigate the effectiveness regarding radiation protection of a SRPS and a PAD in comparison with conventional protection. METHODS: A total of 229 cardiac catheterization procedures with SRPS (N = 73), PAD (N = 82) and standard radiation protection (N = 74) were prospectively included. Real-time dosimeter data were collected from the first operator and the assistant. Endpoints were the cumulative operator exposure relative to the dose area product [standardized operator exposure (SOE)] for the first operator and the assistant. RESULTS: For the first operator, the SRPS and the PAD significantly decreased the overall SOE compared to conventional shielding by 93.9% and 66.4%, respectively (P < 0.001). The protective effect of the SRPS was significantly higher compared to the PAD (P < 0.001). For the assistant, the SRPS and the PAD provided a not statistically significant reduction compared to conventional shielding in the overall SOE by 38.0% and 30.6%, respectively. CONCLUSIONS: The SRPS and the PAD enhance radiation protection significantly compared to conventional protection. In most clinical scenarios, the protective effect of SRPS is significantly higher than the additional protection provided by the PAD. Comparison of the additional radiation protection provided by protective scatter-radiation absorbing drapes (PAD) and the suspended radiation protection system (SRPS) system over standard protection with lead aprons.

[Treatment of Heavily Calcified Coronary Lesions]. / Behandlung schwer verkalkter Koronarläsionen.

Treatment of Heavily Calcified Coronary Lesions Abstract. In Switzerland and other industrialized nations, coronary heart disease (CHD) is the most common cause of death in adulthood. CHD is a chronic disease in which stenoses of the epicardial coronary arteries usually cause a deficit in blood supply to the heart muscle tissue, which can lead to chest pain, myocardial infarction, heart failure or cardiac arrhythmia and ultimately to significant morbidity and mortality. Since the first percutaneous coronary intervention (PCI) on 16th September 1977 at the University Hospital of Zurich by Andreas Grüntzig, the field of interventional cardiology has seen remarkable progress in the treatment of coronary artery disease, especially with the development and evolution of coronary stents. Nonetheless, calcified coronary stenoses pose a challenge in everyday interventional practice because they prevent stent implantation or correct expansion or are associated with a higher rate of complications. Unfortunately, to date, there are no established interventions to prevent calcification of the coronary arteries. However, there are some therapeutic approaches that allow PCI in calcified vessels, and these are the focus of this work.

Longitudinal strain assessed by cardiac magnetic resonance correlates to hemodynamic findings in patients with severe aortic stenosis and predicts positive remodeling after transcatheter aortic valve replacement.

AIMS: To assess left-ventricular strain parameters before and after transcatheter aortic valve replacement (TAVR) by feature tracking cardiac magnetic resonance imaging (FT CMR) and to correlate the findings to hemodynamic state and left-ventricular remodeling. METHODS AND RESULTS: Patients with symptomatic AS underwent FT CMR before and after TAVR. Patients were carefully evaluated by a comprehensive work-up including CMR, echocardiography and left and right heart catheterization. Thirty patients formed the study population. High-flow/high-gradient (HF/HG) aortic stenosis was diagnosed in 11 patients (36.7%), 6 patients (20.0%) exhibited low-flow/low-gradient AS (LF/LG) and 13 patients (43.3%) were classified to have so-called paradoxical low-flow/low-gradient (PLF/LG) AS. The HF/HG patients had a significantly reduced longitudinal strain which recovered after TAVR (-12.67 ± 4.60 to -15.46 ± 5.61%, p = 0.048). In the LF/LG group, an even more pronounced reduction of longitudinal strain and also an impairment of longitudinal velocity could be observed. Both parameters improved after therapy (strain: -5.06 ± 4.25 to -8.02 ± 3.28%, p = 0.045; velocity: 25.33 ± 9.63 to 37.13 ± 11.64 mm/s, p = 0.042). Patients with PLF/LG showed preserved longitudinal strain but a reduction of longitudinal velocity similar to the LF/LG group. These patients did not show a significant improvement of strain parameters after TAVR. Longitudinal velocity exhibited the highest predictive power for the identification of a low-flow state (sensitivity 75%, specificity 80%). CONCLUSION: Improvement of longitudinal strain parameters after TAVR is dependent on the initial hemodynamically defined AS subgroup.

Myocardial strain characteristics and outcomes after transcatheter aortic valve replacement.

BACKGROUND: Objective of this study was to make an assessment of standard functional and defor-mation parameters (strain) in patients after transcatheter aortic valve replacement (TAVR) by cardiac magnetic resonance imaging (CMR) and the evaluation of their prognostic impact. METHODS: Patients undergoing TAVR received CMR on a 1.5 T whole-body scanner at 3 months after the procedure. Deformation parameters (strain, strain rate, velocity, displacement) were assessed in lon-gitudinal, circumferential and radial orientation using a feature tracking approach. Primary outcome measure was defined according to Valve Academic Research Consortium-2 (VARC-2) criteria. RESULTS: Eighty-three patients formed the study population. Deformation parameters were significantly reduced in all three orientations for strain (longitudinal: -12.1 ± 5.4% vs. -15.9 ± 1.96%, p < 0.0001; radial: 34.4 ± 15.3% vs. 47.2 ± 11.4%, p < 0.0001; circumferential: -16.8 ± 4.3% vs. -21.1 ± 2.5%, p < 0.0001) and strain rate (longitudinal: -0.79 ± 0.33%/s vs. -0.91 ± 0.23%/s, p = 0.043; radial: 2.5 ± 1.2%/s vs. 2.9 ± 0.9%, p = 0.067; circumferential: -1.1 ± 0.6%/s vs. -1.3 ± 0.3%/s, p = 0.006) in comparison to a healthy control population. Median follow-up was 614 days. During this period, 13 endpoints occurred (cumulative event rate of 10.7%). Patients with event by trend exhibited poorer strain and strain rate in longitudinal and radial orientation without reaching statistical significance (longitudinal strain: -11.2 ± 5.4% vs. -12.3 ± 5.4%, p = 0.52; longitudinal strain rate: -0.73 ± ± 0.23%/s vs. 0.80 ± 0.35%/s, p = 0.53; radial strain: 29.5 ± 19.6% vs. 35.2 ± 14.5%, p = 0.24; radial strain rate: 2.2 ± 1.6%/s vs. 2.6 ± 1.2%/s, p = 0.31). CONCLUSIONS: Assessment of left ventricular deformation parameters by CMR revealed functional abnormalities in comparison to healthy controls. Prognostic significance remains to be further investi-gated.

Magnetic resonance Adenosine perfusion imaging as Gatekeeper of invasive coronary intervention (MAGnet): study protocol for a randomized controlled trial.

BACKGROUND: Current guidelines for the diagnosis and management of patients with stable coronary artery disease (CAD) recommend functional stress testing for risk stratification prior to revascularization procedures. Cardiac magnetic resonance imaging (CMR) is a modality of choice for stress testing because of its capability to detect myocardial ischemia sensitively and specifically. Nevertheless, evidence from randomized trials evaluating a CMR-based management of stable CAD patients in comparison to a more common angiography-based approach still is limited. METHODS/DESIGN: Patients presenting themselves with symptoms indicating a stable CAD and a class I or IIa indication for diagnostic coronary angiography are prospectively screened and enrolled in the study. All subjects receive a basic cardiological work-up and guideline-directed medical therapy. A 1:1 randomization in two groups is being performed. Patients in group 1 undergo diagnostic coronary angiography and subsequent revascularization according to current guidelines. Subjects in group 2 undergo adenosine stress CMR and in case of myocardial ischemia are sent to coronary angiography. Follow-up is planned for 3 years. During this time, the number of primary endpoints (defined as cardiac death and non-fatal myocardial infarction) and unplanned invasive procedures will be documented. Furthermore, symptom burden and quality of life will be assessed by use of the Seattle Angina Questionnaire. Sample size is calculated to prove non-inferiority of the CMR-based approach. DISCUSSION: In case this study is able to accomplish its aim to prove non-inferiority of the CMR-based management in patients with stable CAD; the importance of this emerging modality may further increase. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02580851 . Registered on 14 October 2015. Unique Protocol ID: 237/11.

Cardiac magnetic resonance imaging derived quantification of myocardial ischemia and scar improves risk stratification and patient management in stable coronary artery disease.

BACKGROUND: Quantification of myocardial ischemia and necrosis might ameliorate prognostic models and lead to improved patient management. However, no standardized consensus on how to assess and quantify these parameters has been established. The aim of this study was to quantify these variables by cardiac magnetic resonance imaging (CMR) and to establish possible incremental implications in cardiovascular risk prediction. METHODS: This study is a retrospective analysis of patients with known or suspected coronary artery disease (CAD) referred for adenosine perfusion CMR was performed. Myocardial ischemia and necrosis were assessed and quantified using an algorithm based on standard first-pass perfusion imaging and late gadolinium enhancement (LGE). The combined primary endpoint was defined as cardiac death, non-fatal myocardial infarction, and stroke. RESULTS: 845 consecutive patients were enrolled into the study. During the median follow-up of 3.64 [1.03; 10.46] years, 61 primary endpoints occurred. Patients with primary endpoint showed larger extent of ischemia (10.7 ± 12.25% vs. 3.73 ± 8.29%, p < 0.0001) and LGE (21.09 ± 15.11% vs. 17.73 ± 10.72%, p < 0.0001). A risk prediction model containing the extent of ischemia and LGE proved to be superior in comparison to all other models (χ² increase: from 39.678 to 56.676, integrated discrimination index: 0.3851, p = 0.0033, net reclassification index: 0.11516, p = 0.0071). The ben-eficial effect of revascularization tended to be higher in patients with greater extents of ischemia, though statistical significance was not reached. CONCLUSIONS: Quantification of myocardial ischemia and LGE was shown to significantly improve existing risk prediction models and might thus lead to an improvement in patient management.