Collateral presence and extent do not predict myocardial viability and ischemia in chronic total occlusions: A stress-CMR study.

BACKGROUND: Well-developed collaterals are assumed as a marker of viability and ischemia in chronic total occlusions (CTO). We aim to correlate viability and ischemia with collateral presence and extent in CTO patients by cardiac magnetic resonance (CMR). METHODS: Multicentre study of 150 CTO patients undergoing stress-CMR, including adenosine if normal systolic function, high-dose-dobutamine for patients with akinetic/>2 hypokinetic segments and EF ≥35%, otherwise low-dose-dobutamine (LDD); all patients underwent late gadolinium enhancement (LGE) imaging. Viability was defined as mean LGE transmurality ≤50% for adenosine, as functional improvement for dobutamine-stress-test, ischemia as ≥1.5 segments with perfusion defects outside the scar zone. RESULTS: Rentrop 3/CC 2 defined well-developed (WD, n = 74) vs poorly-developed collaterals (PD, n = 76). Viability was equally prevalent in WD vs PD: normo-functional myocardium with ≤50% LGE in 52% vs 58% segments, p = 0.76, functional improvement by LDD in 48% vs 52%, p = 0.12. Segments with none, 1-25%,26-50%,51-75% LGE showed viability by LDD in 90%,84%,81%,61% of cases, whilst in 12% if 76-100% LGE (p < 0.01). There was no difference in WD vs PD for ischemia presence (74% vs 75%, p = 0.99) and extent (2.7 vs 2.8 segments, p = 0.77). CONCLUSIONS: In a large cohort of CTO patients, presence and extent of collaterals did not predict viability and ischemia by stress-CMR. Scar extent up to 75% LGE was still associated with viability, whereas ischemia was undetectable in 25% of patients, suggesting that the assessment of CTO patients with CMR would lead to a more comprehensive evaluation of viability and ischemia to guide revascularization.

Phantom study of stereotactic radioablation for ventricular tachycardia (STRA-MI-VT) using Cyberknife Synchrony Respiratory Tracking System with a single fiducial marker.

PURPOSE: Within the STRA-MI-VT phase Ib/II trial (NCT04066517), the aim of this phantom study was to explore the feasibility of Cyberknife treatments on cardiac lesions by tracking as a single marker the lead tip of an implantable cardioverter defibrillator. The residual displacement of the lesion during the tracking was studied, planning margins were found and the dosimetric accuracy of the treatment was checked. MATERIALS AND METHODS: A lead was inserted into a phantom (EasyCube phantom, Sun Nuclear Co, USA) and then placed on the translating ExacTrac Gating System (BrainLAB AG, Germany). The phantom was rotated, a virtual lesion was identified and its displacement during the tracking was studied. Two plans were compared, calculated on the unrotated volume and on the envelope of the unrotated and the rotated volumes. The plans were delivered using the Cyberknife System (Accuray Inc, USA) and their dosimetric accuracy verified by gamma analysis with gafchromic films. RESULTS: The residual margin increases enhancing the distance between the lead and the lesion. It is 4 mm for distance 0 cm and 5 mm for distance 5 cm. The coverage is reduced by 3.8% (interquartile range 2.5%-4.7%) when the dose is prescribed on the unrotated volume. All treatment plans are accurate and 3% 3 mm gamma analysis results are greater than 94%. CONCLUSIONS: Results showed that tracking with a single marker is feasible considering adequate residual planning margins. The volumes could be further reduced by using additional markers, for example by placing them on the patient's skin.

Feasibility study of a mixed reality tool for real 3D visualization and planning of left atrial appendage occlusion.

In left atrial appendage occlusion (LAAO), pre-procedural imaging is pivotal to describe the highly variable LAA anatomy and to guide the operator in device sizing and interventional planning. Multiplanar reconstruction and 3D rendering are used for the interpretation of 3D CT datasets. However, this method of review of such imaging, which is mediated by 2D screens, may be limited due to the lack of true 3D visualization of the structures of interest; Mixed Reality (MxR) may further improve the CT-based pre-procedural planning by allowing for real-3D visualizations with holographic replicas of anatomical models. In this manuscript we present a novel software based on MxR and we evaluated its feasibility on different LAA morphologies. The morphological analysis of the holographic anatomical models was successfully applied for all the patients (n â€‹= â€‹4) independently from the morphology and it was performed in less than 10 minutes. Our findings suggest that with further developments MxR could have the potential to become a pivotal tool in LAA occlusion planning thanks to the real-3D perception, possibly leading to a more accurate and faster planning phase.

Physiological and angiographic outcomes of PCI in calcified lesions after rotational atherectomy or intravascular lithotripsy.

BACKGROUND: Percutaneous coronary interventions (PCI) in calcified coronary artery lesions are associated with impaired stent expansion, higher rate of periprocedural complications and cardiac mortality. Lesion preparation using calcium modifying techniques such as Rotational Atherectomy (RA) or Intravascular Lithotripsy (IVL) has been advocated. Studies comparing these technologies are lacking. We aimed to compare in-stent pressure gradients, evaluated by vessel fractional flow reserve (vFFR), in calcific lesions treated using either RA or IVL. METHODS: Patients undergoing either RA- or IVL-assisted PCI from two European centers were included. Propensity score matching (1:2) was performed to control for potential bias. Primary outcome was post-PCI in-stent pressure gradients calculated by vFFR (vFFRgrad). Secondary outcomes included the proportion of patients with complete functional revascularization defined as distal vFFR post-PCI (vFFRpost) ≥ 0.90. RESULTS: From a cohort of 210 patients, 105 matched patients (70 RA and 35 IVL) were included. Pre-PCI vFFR did not differ between groups (0.65 ± 0.13 RA and 0.67 ± 0.11 IVL). After PCI, in-stent pressure gradients were significantly lower in the IVL group (0.032 ± 0.026 vs 0.043 ± 0.026 in the RA group, p = 0.024). The proportions of vessels with functional complete revascularization was similar between the two groups (32.9% vs. 37.1% in the RA and IVL group, respectively; p = 0.669). CONCLUSIONS: Calcific lesions preparation with IVL is effective and resulted in lower in-stent pressure gradients compared to RA. Approximately one third of the patients undergoing PCI for a severely calcified lesion achieved functional revascularization with no difference between rotational RA and IVL.

STRA-MI-VT (STereotactic RadioAblation by Multimodal Imaging for Ventricular Tachycardia): rationale and design of an Italian experimental prospective study.

BACKGROUND: Ventricular tachycardia (VT) is a life-threatening condition, which usually implies the need of an implantable cardioverter defibrillator in combination with antiarrhythmic drugs and catheter ablation. Stereotactic body radiotherapy (SBRT) represents a common form of therapy in oncology, which has emerged as a well-tolerated and promising alternative option for the treatment of refractory VT in patients with structural heart disease. OBJECTIVE: In the STRA-MI-VT trial, we will investigate as primary endpoints safety and efficacy of SBRT for the treatment of recurrent VT in patients not eligible for catheter ablation. Secondary aim will be to evaluate SBRT effects on global mortality, changes in heart function, and in the quality of life during follow-up. METHODS: This is a spontaneous, prospective, experimental (phase Ib/II), open-label study (NCT04066517); 15 patients with structural heart disease and intractable VT will be enrolled within a 2-year period. Advanced multimodal cardiac imaging preceding chest CT-simulation will serve to elaborate the treatment plan on different linear accelerators with target and organs-at-risk definition. SBRT will consist in a single radioablation session of 25 Gy. Follow-up will last up to 12 months. CONCLUSIONS: We test the hypothesis that SBRT reduces the VT burden in a safe and effective way, leading to an improvement in quality of life and survival. If the results will be favorable, radioablation will turn into a potential alternative option for selected patients with an indication to VT ablation, based on the opportunity to treat ventricular arrhythmogenic substrates in a convenient and less-invasive manner.

Quantification of calcium burden by coronary CT angiography compared to optical coherence tomography.

Coronary artery calcifications (CAC) are frequently observed in patients referred for coronary CT angiography (CTA). Calcification volume (in mm3) can accurately be assessed during catheterization by optical coherence tomography (OCT). The aim of the present study was to investigate the accuracy of CTA-derived assessment of calcification volume as compared with OCT. 66 calcified plaques (32 vessels) from 31 patients undergoing OCT-guided PCI with coronary CT acquired as a standard of care were included. Coronary CT and OCT images were matched using fiduciary points. Calcified plaques were reconstructed in three dimensions to calculate calcium volume. A Passing-Bablok regression analysis and the Bland-Altman method were used to assess the agreement between imaging modalities. Twenty-seven left anterior descending arteries and 5 right coronary arteries were analyzed. Median calcium volume by CTA and OCT were 18.23 mm3 [IQR 8.09, 36.48] and 10.03 mm3 [IQR 3.6, 22.88] respectively; the Passing-Bablok analysis showed a proportional without a systematic difference (Coefficient A 0.08, 95% CI - 1.37 to 1.21, Coefficient B 1.61, 95% CI 1.45 to 1.84) and the mean difference was 9.69 mm3 (LOA - 10.2 to 29.6 mm3). No differences were observed for minimal lumen area (Coefficient A 0.07, 95% CI - 0.46 to 0.15, Coefficient B 0.85, 95% CI 0.64 to 1.2). CTA volumetric calcium evaluation overestimates calcium volume by 60% compared to OCT. This may allow for an appropriate interpretation of calcific burden in the non-invasive setting. Even in presence of calcific plaques, a good agreement in the MLA assessment was found. Coronary CT may emerge as a tool to quantify calcium burden for invasive procedural planning.

Cardiac magnetic resonance for ischaemia and viability detection. Guiding patient selection to revascularization in coronary chronic total occlusions: The CARISMA_CTO study design.

BACKGROUND: It is debated whether percutaneous revascularization (PCI) of total coronary chronic occlusion (CTO) is superior to optimal medical therapy (OMT) in improving symptoms, left ventricular (LV) function and major adverse cardiac/cerebrovascular events (MACCE). Furthermore, CTO-PCI is a challenging technique, with lower success rate than in other settings. A systematic analysis of baseline LV function, infarction extent and ischaemic burden to predict response to revascularization has never been performed. PURPOSES: To establish a CMR protocol to identify patients (pts) who can benefit most from CTO-PCI. Myocardial viability/ischaemia retains high biological plausibility as predictors of response to revascularization. Therefore, baseline viability (necrotic tissue extent, response to inotropic stimulation) and ischaemia (perfusion defect, wall motion abnormality during stress) will be studied as potential predictors of mechanical LV segmental improvement and ischaemic burden reduction in CTO territory (primary endpoint), LV remodelling and global function, Seattle Angina Questionnaire, and MACCE improvement (secondary endpoints) in the follow-up. METHODS: Pts with CTO suitable for PCI undergo stress-CMR for viability/ischaemia assessment. Pts with normal LV function undergo adenosine, those with moderately-reduced ejection fraction (EF) and wall motion abnormalities high-dose dobutamine, pts with EF <35% low-dose dobutamine. All pts undergo late gadolinium enhancement and repeat the same scan at 12 ±â€¯3 months, regardless of PCI success or decision for OMT. CONCLUSIONS: A multi-parameter CMR protocol tailored on pts characteristics to study viability/ischaemia could help in identifying responders in terms of LV function, ischaemic burden and clinical outcome among pts suitable for CTO-PCI, improving selection of best candidates to percutaneous revascularization.

Ultra-low-dose CT for left atrium and pulmonary veins imaging using new model-based iterative reconstruction algorithm.

AIMS: To evaluate the feasibility of ultra-low-dose CT for left atrium and pulmonary veins using new model-based iterative reconstruction (MBIR) algorithm. METHODS AND RESULTS: Two hundred patients scheduled for catheter ablation were randomized into two groups: Group 1 (100 patients, Multidetector row CT (MDCT) with MBIR, no ECG triggering, tube voltage and tube current of 100 kV and 60 mA, respectively) and Group 2 [100 patients, MDCT with adaptive statistical iterative reconstruction algorithm (ASIR), no ECG triggering, and kV and mA tailored on patient BMI]. Image quality, CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of left atrium (LA) and pulmonary veins, and effective dose (ED) were evaluated for each exam and compared between two groups.No significant differences between groups in terms of population characteristics, cardiovascular risk factors, anatomical features, prevalence of persistent atrial fibrillation and image quality score. Statistically significant differences were found between Group 1 and Group 2 in mean attenuation, SNR, and CNR of LA. Significantly, lower values of noise were found in Group 1 versus Group 2. Group 1 showed a significantly lower mean ED in comparison with Group 2 (0.41 ± 0.04 versus 4.17 ± 2.7 mSv). CONCLUSION: The CT for LA and pulmonary veins imaging using MBIR is feasible and allows examinations with very low-radiation exposure without loss of image quality.

Feasibility and diagnostic accuracy of a low radiation exposure protocol for prospective ECG-triggering coronary MDCT angiography.

AIM: To compare the feasibility, accuracy, and effective radiation dose (ED) of multidetector computed tomography (MDCT) in the detection of coronary artery disease using a combined ED-saving strategy including prospective electrocardiogram (ECG) triggering with a short x-ray window and a body mass index (BMI)-adapted imaging protocol using adaptive statistical iterative reconstruction (ASIR; group 1), in comparison with a prospective ECG triggering strategy alone (group 2). MATERIALS AND METHODS: One hundred and seventy patients scheduled for invasive coronary angiography (ICA) were evaluated. Fourteen patients were not eligible for MDCT. The remaining 156 patients were randomized to group 1 (78 patients) and group 2 (78 patients). Eight and 11 patients in groups 1 and 2, respectively, were excluded after randomization because the patients' heart rates were >65 beats/min. MDCT images were assessed for feasibility, signal-to-noise ration (SNR), and contrast-to-noise ratio (CNR), accuracy in detection of coronary stenoses >50% versus ICA and for ED. RESULTS: The feasibility, SNR, CNR, accuracy in a segment-based and patient-based model were similar in both groups (97 versus 95%, 14.5 ± 3.9 versus 14.2 ± 4.1, 16 ± 4.6 versus 16.5 ± 4.4, 95 versus 94% and 97 versus 99%, respectively). The ED in group 1 was 72% lower than in group 2 (2.1 ± 1.2 versus 7.5 ± 1.8 mSv, respectively; p<0.01). CONCLUSIONS: The use of a multi-parametric ED saving protocol results in a significant reduction in ED without a negative impact on accuracy.

Accuracy of multidetector spiral computed tomography in detecting significant coronary stenosis in patient populations with differing pre-test probabilities of disease.

AIM: To investigate the clinical impact of multidetector computed tomography (MDCT) in patients with a low versus a high pre-test likelihood of coronary artery disease (CAD). MATERIALS AND METHODS: A cohort of 120 patients with suspected CAD, scheduled for conventional coronary angiography, underwent MDCT. Using the American Heart Association (AHA)/American College of Cardiology (ACC) guidelines, the population was divided into two groups: patients with a low (group 1) and a high (group 2) likelihood of CAD. RESULTS: Analysis of all segments showed a high feasibility (92%), and a patient based-model showed excellent sensitivity and negative predictive values (NPV; both 100%) and acceptable specificity and positive predictive values (PPV; 86 and 90%, respectively), with an accuracy of 94%. Using MDCT in patients with lower pre-test likelihoods of CAD, according to the ACC/AHA guidelines, the accuracy remained high (93%); conversely, in patient groups with a high prevalence of CAD, a non-significant reduction in accuracy (85%) occurred using MDCT. Particularly, MDCT can be used effectively to exclude a diagnosis of CAD because of its high sensitivity and NPV (100%), but shows a significant reduction in specificity (58%). This reduction was due to an increase in the false-positive:true-negative ratio because of the higher percentage of calcified plaque (a relative but non-significant increase in false positives), and the high prevalence of CAD (significant reduction in true negatives). No differences were found between MDCT and quantitative coronary angiography (QCA) concerning the number of vessels narrowed. CONCLUSION: Because of its excellent sensitivity and specificity in patients with a low pre-test likelihood of CAD, MDCT could be helpful in clinical decision-making in this population.

[Myocardial revascularization with both internal mammary arteries]. / Rivascolarizzazione miocardica con entrambe le arterie mammarie interne.

BACKGROUND: The excellent results obtained with the use of the left internal mammary artery (IMA) for myocardial revascularization have led to the simultaneous use of other arterial conduits, particularly the right IMA. METHODS: The present study includes the first 100 consecutive patients with ischemic heart disease who underwent myocardial revascularization with in situ bilateral IMA grafted to branches of the left coronary artery, performed at our center. Ninety-six (96%) were males and four (4%) were females, with a mean age of 58 +/- 8 years (range, 35-75 years). The main indication for myocardial revascularization was angina in 83 patients (83%) and heart failure in 17 (17%). Seventy patients had three-vessel disease. RESULTS: Hospital mortality was 1%, with one death due to left ventricular failure. Three patients had perioperative myocardial infarction, six experienced ventricular arrhythmia, two had acute renal failure and nine respiratory insufficiency. Dehiscence of the sternal wound occurred in four patients, evolving in mediastinitis in one. All discharged patients were checked after 26 +/- 6 months (range, 12-38 months). There were two deaths, one because of cardiac failure and one sudden death, with a two-year survival rate of 97 +/- 2%. Five patients (5%) required hospitalization because of angina, and the angiographic study showed stenosis/occlusion of one or both IMAs in four cases. Thirty-five (38%) of the remaining patients underwent a coronarographic (25 patients) or transthoracic Doppler study (10 patients) to evaluate patency of the IMAs. The patency index was 100% for the left IMA and 94% for the right IMA. CONCLUSIONS: Myocardial revascularization with bilateral IMA in situ can be performed with low hospital mortality and morbidity. Sternal dehiscence is the worst complication and appears to be more frequent in diabetic and elderly patients. Mid-term results are satisfactory, with a good survival rate and freedom from major cardiac events. However, a longer follow-up is necessary to better appreciate the advantages of myocardial revascualarization with in situ bilateral IMAs.

[Congenital tricuspid insufficiency due to valvular dysplasia]. / L'insufficienza tricuspidale congenita da displasia valvolare.

A case of congenital tricuspid incompetence in a 39 year old woman is reported. The patient, who was in suffering congestive heart failure, had no history of trauma, myocardial infarction, rheumatic fever, infective endocarditis. Right ventriculography and right atrial pressure recording both showed signs of severe tricuspid insufficiency. Echocardiography showed dilatation of the right ventricle and atrium, and the lack of normal systolic coaptation of anterior and septal tricuspid leaflets, while contrast echocardiography gave direct evidence of regurgitation. Valvular replacement with a bioprosthesis was carried out. The diagnosis of congenital tricuspid incompetence was confirmed at operation. The patient is asymptomatic at one year follow up.