Long-term impact of intravascular ultrasound-guidance for percutaneous coronary intervention on unprotected left main. The IMPACTUS-LM, an observational, multicentric study.

INTRODUCTION: The potential benefit on long term outcomes of Percutaneous Coronary Intervention (PCI) on Unprotected Left Main (ULM) driven by IntraVascular UltraSound (IVUS) remains to be defined. METHODS: IMPACTUS LM-PCI is an observational, multicenter study that enrolled consecutive patients with ULM disease undergoing coronary angioplasty in 13 European high-volume centers from January 2002 to December 2015. Major Adverse Cardiovascular Events (MACEs) a composite of cardiovascular (CV) death, target vessel revascularization (TVR) and myocardial infarction (MI) were the primary endpoints, while its single components along with all cause death the secondary ones. RESULTS: 627 patients with ULM disease were enrolled, 213 patients (34%) underwent IVUS-guided PCI while 414 (66%) angioguided PCI. Patients in the two cohorts had similar prevalence of risk factors except for active smoking and clinical presentation. During a median follow-up of 7.5 years, 47 (22%) patients in the IVUS group and 211 (51%) in the angio-guided group underwent the primary endpoint (HR 0.42; 95% CI [0.31-0.58] p < 0.001). After multivariate adjustment, IVUS was significantly associated with a reduced incidence of the primary endpoint (adj HR 0.39; 95% CI [0.23-0.64], p < 0.001), mainly driven by a reduction of TVR (ad HR 0.30, 95% CI [0.15-0.62], p = 0.001) and of all-cause death (adj HR 0.47, 95% CI [0.28-0.82], p = 0.008). IVUS use, age, diabetes, side branch stenosis, DES and creatinine at admission were independent predictors of MACE. CONCLUSIONS: In patients undergoing ULM PCI, the use of IVUS was associated with a reduced risk at long-term follow-up of MACE, all-cause death and subsequent revascularization.

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.

Saline-induced coronary hyperemia with continuous intracoronary thermodilution is mediated by intravascular hemolysis.

BACKGROUND AND AIMS: Absolute coronary flow can be measured by intracoronary continuous thermodilution of saline through a dedicated infusion catheter (RayFlow®). A saline infusion rate at 15-20 mL/min induces an immediate, steady-state, maximal microvascular vasodilation. The mechanism of this hyperemic response remains unclear. We aimed to test whether local hemolysis is a potential mechanism of saline-induced coronary hyperemia. METHODS: Twelve patients undergoing left and right catheterization were included. The left coronary artery and the coronary sinus were selectively cannulated. Absolute resting and hyperemic coronary flow were measured by continuous intracoronary thermodilution. Arterial and venous samples were collected from the coronary artery and the coronary sinus in five phases: baseline (BL); resting flow measurement (Rest, saline infusion at 10 mL/min); hyperemia (Hyperemia, saline infusion at 20 mL/min); post-hyperemia (Post-Hyperemia, 2 min after the cessation of saline infusion); and control phase (Control, during infusion of saline through the guide catheter at 30 mL/min). RESULTS: Hemolysis was visually detected only in the centrifugated venous blood samples collected during the Hyperemia phase. As compared to Rest, during Hyperemia both LDH (131.50 ± 21.89 U/dL [Rest] and 258.33 ± 57.40 U/dL [Hyperemia], p < 0.001) and plasma free hemoglobin (PFHb, 4.92 ± 3.82 mg/dL [Rest] and 108.42 ± 46.58 mg/dL [Hyperemia], p < 0.001) significantly increased in the coronary sinus. The percentage of hemolysis was significantly higher during the Hyperemia phase (0.04 ± 0.02% [Rest] vs 0.89 ± 0.34% [Hyperemia], p < 0.001). CONCLUSIONS: Saline-induced hyperemia through a dedicated intracoronary infusion catheter is associated with hemolysis. Vasodilatory compounds released locally, like ATP, are likely ultimately responsible for localized microvascular vasodilation.

Microvascular Resistance Reserve for Assessment of Coronary Microvascular Function: JACC Technology Corner.

The need for a quantitative and operator-independent assessment of coronary microvascular function is increasingly recognized. We propose the theoretical framework of microvascular resistance reserve (MRR) as an index specific for the microvasculature, independent of autoregulation and myocardial mass, and based on operator-independent measurements of absolute values of coronary flow and pressure. In its general form, MRR equals coronary flow reserve (CFR) divided by fractional flow reserve (FFR) corrected for driving pressures. In 30 arteries, pressure, temperature, and flow velocity measurements were obtained simultaneously at baseline (BL), during infusion of saline at 10 mL/min (rest) and 20 mL/min (hyperemia). A strong correlation was found between continuous thermodilution-derived MRR and Doppler MRR (r = 0.88; 95% confidence interval: 0.72-0.93; P < 0.001). MRR was independent from the epicardial resistance, the lower the FFR value, the greater the difference between MRR and CFR. Therefore, MRR is proposed as a specific, quantitative, and operator-independent metric to quantify coronary microvascular dysfunction.

Simplified Assessment of the Index of Microvascular Resistance.

BACKGROUND: To validate a simplified invasive method for the calculation of the index of microvascular resistance (IMR). METHODS: This is a prospective, single-center study of patients with chronic coronary syndromes presenting with nonobstructive coronary artery disease. IMR was obtained using both intravenous (IV) adenosine and intracoronary (IC) papaverine. Each IMR measurement was obtained in duplicate. The primary objective was the agreement between IMR acquired using adenosine and papaverine. Secondary objectives include reproducibility of IMR and time required for the IMR measurement. RESULTS: One hundred and sixteen IMR measurements were performed in 29 patients. The mean age was 68.8 ± 7.24 years, and 27.6% was diabetics. IMR values were similar between papaverine and adenosine (17.7 ± 7.26 and 20.1 ± 8.6, p=0.25; Passing-Bablok coefficient A 0.58, 95% CI -2.42 to 3.53; coefficient B 0.90, 95% CI -0.74 to 1.07). The reproducibility of IMR was excellent with both adenosine and papaverine (ICC 0.78, 95% CI 0.63 to 0.88 and ICC 0.93, 95% CI 0.87 to 0.97). The time needed for microvascular assessment was significantly shortened by the use of IC papaverine (3.23 (2.84, 3.78) mins vs. 5.48 (4.94, 7.09) mins, p < 0.0001). CONCLUSION: IMR can be reliably measured using IC papaverine with similar results compared to intravenous infusion of adenosine with increased reproducibility and reduced procedural time. This approach simplifies the invasive assessment of the coronary microcirculation in the catheterization laboratory.

Improving 1-year mortality prediction in ACS patients using machine learning.

BACKGROUND: The Global Registry of Acute Coronary Events (GRACE) score is an established clinical risk stratification tool for patients with acute coronary syndromes (ACS). We developed and internally validated a model for 1-year all-cause mortality prediction in ACS patients. METHODS: Between 2009 and 2012, 2'168 ACS patients were enrolled into the Swiss SPUM-ACS Cohort. Biomarkers were determined in 1'892 patients and follow-up was achieved in 95.8% of patients. 1-year all-cause mortality was 4.3% (n = 80). In our analysis we consider all linear models using combinations of 8 out of 56 variables to predict 1-year all-cause mortality and to derive a variable ranking. RESULTS: 1.3% of 1'420'494'075 models outperformed the GRACE 2.0 Score. The SPUM-ACS Score includes age, plasma glucose, NT-proBNP, left ventricular ejection fraction (LVEF), Killip class, history of peripheral artery disease (PAD), malignancy, and cardio-pulmonary resuscitation. For predicting 1-year mortality after ACS, the SPUM-ACS Score outperformed the GRACE 2.0 Score which achieves a 5-fold cross-validated AUC of 0.81 (95% CI 0.78-0.84). Ranking individual features according to their importance across all multivariate models revealed age, trimethylamine N-oxide, creatinine, history of PAD or malignancy, LVEF, and haemoglobin as the most relevant variables for predicting 1-year mortality. CONCLUSIONS: The variable ranking and the selection for the SPUM-ACS Score highlight the relevance of age, markers of heart failure, and comorbidities for prediction of all-cause death. Before application, this score needs to be externally validated and refined in larger cohorts. CLINICAL TRIAL REGISTRATION: NCT01000701.

MitraClip and Transcatheter Aortic Valve Implantation (TAVI): State of the Art 2015.

The feasibility, safety, and efficacy of transcatheter heart valve (THV) therapies such as MitraClip and transcatheter aortic valve implantation (TAVI) have made them valid therapeutic options in high-risk or inoperable patients with heart failure (HF). Randomized controlled trials (RCTs) demonstrated noninferiority and superiority in terms of efficacy for 12 months of TAVI versus surgical replacement and optimal medical therapy, respectively. With regard to MitraClip, noninferiority was first demonstrated in four subgroups at 12 months and then later at 4-year follow-up. This difference in clinical outcomes between the two therapies is consistent with the discrepancy in the level of recommendation and class of evidence for TAVI and MitraClip according to recent international guidelines (IB vs. IIbC, respectively). Data from ongoing RCTs and national registries will help establish the reciprocal role and hierarchy among THV therapies, surgery, and medical treatment in patients with HF.